Tesis: "Cylindrospermopsin"

1

Smith, Maree J. "Biodegradation of the cyanotoxin cylindrospermopsin /". [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18474.pdf.

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2

Bain, Peter A. y n/a. "Gene Expression Profiling of Cylindrospermopsin Toxicity". Griffith University. School of Biomolecular and Physical Sciences, 2007. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20080404.145834.

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Cylindrospermopsin (CYN) is a toxic alkaloid produced by several freshwater cyanobacterial species, the most prevalent in Australian waters being Cylindrospermopsis raciborskii. The occurrence of CYN-producing cyanobacteria in drinking water sources worldwide poses a potential human health risk, with one well-documented case of human poisoning attributed to the toxin. While extensive characterisation of CYN-induced toxicity has been conducted in rodents both in vivo and in primary cell cultures, little is known about mechanisms of toxicity in human cell types. This thesis describes studies undertaken to further define the molecular mechanisms of CYN toxicity in human cells. Concentration-response relationships were determined in various cultured human cell types using standard toxicity assays. As expected, CYN caused dose-dependent decreases in the growth of three cell lines, HepG2, Caco-2 and HeLa, and one primary cell type, human dermal fibroblasts, according to tetrazolium reduction assays. CYN treatment did not disrupt cellular membranes according to the lactate dehydrogenase release assay in HepG2 or Caco-2 cells after 24, 48 or 72 h exposure, but did cause membrane disruption in fibroblasts after 72 h exposure to relatively high concentrations of the toxin. Apoptosis occurred more readily in HeLa cells than HepG2 cells or fibroblasts, with 72 h exposure to 1 &mug/mL required before statistically significant rates of apoptosis occurred in the latter cell types. CYN did not appear to directly affect the structure of actin filaments or microtubules under the conditions used in the present study. The major portion of the work presented in this thesis comprises a large-scale interrogation of changes in gene expression induced by the toxin in cultured cells. To assess the effects of CYN on global gene expression, relative messenger RNA (mRNA) levels in human dermal fibroblasts and HepG2 cells after 6 h and 24 h exposure to 1 &mug/mL CYN were determined using oligonucleotide microarrays representing approximately 19 000 genes. Overall, the number of transcripts significantly altered in abundance was greater in fibroblasts than in HepG2 cells. In both cell types, mRNA levels for genes related to amino acid biosynthesis, carbohydrate metabolism, and protein folding and transport were reduced after CYN treatment, while transcripts representing genes for apoptosis, RNA biosynthesis and RNA processing increased in abundance. More detailed data analyses revealed the modulation of a number of stress response pathways—genes regulated by NF-&kappaB were induced, DNA damage response pathways were up-regulated, and a large number of genes involved in endoplasmic reticulum stress were strongly down-regulated. Genes for the synthesis and processing of mRNA, tRNA and rRNA were strongly up-regulated, indicating that CYN treatment may increase the turnover of all forms of cellular RNA. A small group of genes were differentially expressed in HepG2 cells and fibroblasts, revealing cell-specific responses to the toxin. Selected changes in transcript level were validated using real-time quantitative reverse transcriptase PCR (qRT-PCR). The modulation of stress response pathways by CYN, indicated by microarray analysis, was further investigated using other methods. The role of tumour suppressor protein p53 in CYN-mediated gene expression was confirmed by measuring the expression of known p53-regulated genes following CYN treatment of HepG2 cells and human dermal fibroblasts using qRT-PCR. Western blotting of protein extracts from CYNtreated cells showed that p53 protein accumulation occurred in HepG2 cells, providing additional evidence of the activation of the p53 pathway by CYN in this cell line. The immediate-early genes JUN and FOS were found to be induced by CYN in a concentration-dependent manner, and MYC was induced to a lesser extent. The mitogen-activated protein kinase c-Jun NH2-terminal kinase, implicated in the ribotoxic stress response initiated by damage to ribosomal RNA, appeared to become phosphorylated in HeLa cells after CYN exposure, suggesting that ribotoxic stress may occur in response to CYN in at least some cell types. The expression of a reporter gene under the control of a response element specific for NF-&kappaB was induced at the mRNA level but inhibited at the protein level. This shows that while transcription factors such as p53 and NF-&kappaB are apparently activated in response to the toxin, transactivation of target genes may not necessarily manifest a corresponding increase at the protein level. The current work contributes significantly to the current understanding of cylindrospermopsin toxicity in human-derived cell types, and provides further insight into putative modes of action.

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3

Evans, Daniel Mackenzie. "Synthetic steps towards the cylindrospermopsin alkaloids". Thesis, Bangor University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590643.

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Detailed herein is the tethered Biginelli condensation between irninium ion 201 and beta keto ester 206 leading to a model tricyclic ring system representative of the guanidinium core of cylindrospennopsin alkaloids. This was achieved in a biosynthetically-inspired manner in 12 steps and 8.3% overall yield from simple, commercially available 1,5-pentanediol 172. Also discussed is the adaption of this methodology to allow for the highly efficient stereoselective synthesis of all 3 of the cylindrospermopsin alkaloids and the preparation of the advanced synthetic intermediate nitro-alcohol 223.

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4

Bain, Peter A. "Gene Expression Profiling of Cylindrospermopsin Toxicity". Thesis, Griffith University, 2007. http://hdl.handle.net/10072/367068.

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Cylindrospermopsin (CYN) is a toxic alkaloid produced by several freshwater cyanobacterial species, the most prevalent in Australian waters being Cylindrospermopsis raciborskii. The occurrence of CYN-producing cyanobacteria in drinking water sources worldwide poses a potential human health risk, with one well-documented case of human poisoning attributed to the toxin. While extensive characterisation of CYN-induced toxicity has been conducted in rodents both in vivo and in primary cell cultures, little is known about mechanisms of toxicity in human cell types. This thesis describes studies undertaken to further define the molecular mechanisms of CYN toxicity in human cells. Concentration-response relationships were determined in various cultured human cell types using standard toxicity assays. As expected, CYN caused dose-dependent decreases in the growth of three cell lines, HepG2, Caco-2 and HeLa, and one primary cell type, human dermal fibroblasts, according to tetrazolium reduction assays. CYN treatment did not disrupt cellular membranes according to the lactate dehydrogenase release assay in HepG2 or Caco-2 cells after 24, 48 or 72 h exposure, but did cause membrane disruption in fibroblasts after 72 h exposure to relatively high concentrations of the toxin. Apoptosis occurred more readily in HeLa cells than HepG2 cells or fibroblasts, with 72 h exposure to 1 µg/mL required before statistically significant rates of apoptosis occurred in the latter cell types. CYN did not appear to directly affect the structure of actin filaments or microtubules under the conditions used in the present study. The major portion of the work presented in this thesis comprises a large-scale interrogation of changes in gene expression induced by the toxin in cultured cells. To assess the effects of CYN on global gene expression, relative messenger RNA (mRNA) levels in human dermal fibroblasts and HepG2 cells after 6 h and 24 h exposure to 1 µg/mL CYN were determined using oligonucleotide microarrays representing approximately 19 000 genes. Overall, the number of transcripts significantly altered in abundance was greater in fibroblasts than in HepG2 cells. In both cell types, mRNA levels for genes related to amino acid biosynthesis, carbohydrate metabolism, and protein folding and transport were reduced after CYN treatment, while transcripts representing genes for apoptosis, RNA biosynthesis and RNA processing increased in abundance. More detailed data analyses revealed the modulation of a number of stress response pathways—genes regulated by NF-?B were induced, DNA damage response pathways were up-regulated, and a large number of genes involved in endoplasmic reticulum stress were strongly down-regulated. Genes for the synthesis and processing of mRNA, tRNA and rRNA were strongly up-regulated, indicating that CYN treatment may increase the turnover of all forms of cellular RNA. A small group of genes were differentially expressed in HepG2 cells and fibroblasts, revealing cell-specific responses to the toxin. Selected changes in transcript level were validated using real-time quantitative reverse transcriptase PCR (qRT-PCR). The modulation of stress response pathways by CYN, indicated by microarray analysis, was further investigated using other methods. The role of tumour suppressor protein p53 in CYN-mediated gene expression was confirmed by measuring the expression of known p53-regulated genes following CYN treatment of HepG2 cells and human dermal fibroblasts using qRT-PCR. Western blotting of protein extracts from CYNtreated cells showed that p53 protein accumulation occurred in HepG2 cells, providing additional evidence of the activation of the p53 pathway by CYN in this cell line. The immediate-early genes JUN and FOS were found to be induced by CYN in a concentration-dependent manner, and MYC was induced to a lesser extent. The mitogen-activated protein kinase c-Jun NH2-terminal kinase, implicated in the ribotoxic stress response initiated by damage to ribosomal RNA, appeared to become phosphorylated in HeLa cells after CYN exposure, suggesting that ribotoxic stress may occur in response to CYN in at least some cell types. The expression of a reporter gene under the control of a response element specific for NF-?B was induced at the mRNA level but inhibited at the protein level. This shows that while transcription factors such as p53 and NF-?B are apparently activated in response to the toxin, transactivation of target genes may not necessarily manifest a corresponding increase at the protein level. The current work contributes significantly to the current understanding of cylindrospermopsin toxicity in human-derived cell types, and provides further insight into putative modes of action.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Faculty of Science, Environment, Engineering and Technology
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5

Djung, Jane F. "An approach toward the total synthesis of cylindrospermopsin /". The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486397841223073.

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6

Catlin, Diane M. "DNA Aptamer Confirmation and Utilization for the Cyanotoxin, Cylindrospermopsin". FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2552.

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Cyanotoxins are posing an increasing threat to the health of humans and wildlife. Cylindrospermopsin is a cyanotoxin that occurs in warm climates and is harmful when ingested. The toxic effects of CYN can affect multiple organ systems. The effects, coupled with the evidence of a mass contamination of a water supply in Australia, prove that CYN needs to be investigated further. Aptamers have become a desirable method for detection of CYN as a result of an aptamer’s high specificity and the ability to scale up experiments. Aptamers have been designed to bind with a variety of targets, including cyanotoxins. An aptamer for CYN was identified by Elshafey et al. This study aims to confirm the binding of the aptamer to CYN and the selectivity of the aptamer using fluorescent biosensing and circular dichroism. Aptamer affinity capture was used to investigate the possibility of a real world application of the aptamer.

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7

Littler, Benjamin Joseph. "Synthetic studies directed towards cylindrospermopsin : cyclisations of cyclic sulfates". Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337289.

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8

Blanco, Carlos Andrey González. "A non-targeted proteomics investigation of cylindrospermopsin-induced hepatotoxicity". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/9/9143/tde-19102017-153400/.

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Cyanobacteria is perhaps the phylum that profit the most from the escalating hypereutrophication of continental waters. The resulting cyanobacterial blooms may accumulate a variety of potent toxins. Cylindrospermopsin (CYN) is a cyanotoxin known for inhibiting protein synthesis, and producing oxidative stress as well as DNA damage in eukaryotic cells. Since the toxin\'s molecular mechanisms and targets are still unclear, we purified the cyanotoxin from our lab strains and employed a shotgun proteomics approach to reveal the major changes in HepG2 cells at sublethal doses of CYN (1 µM for 6, 12 and 24h). Metabolically labeled cells were stimulated and lysed after each treatment, their tryptic digests were separated by nano HPLC and analyzed by high-resolution tandem mass spectrometry (HRMS) on data dependent acquisition mode. We scanned an average of 4000 proteins in every sample throughout the three timepoints. Cholesterol biosynthesis and transport was mostly downregulated throughout the timepooints of the experiment. Downregulation of proteins related to ubiquitination (e.g. UBE2L3) and proteolysis pathways (e.g. PSMA2) was observed in the proteomics dataset, and these results were validated by western blot. Transcription, translation and cell cycle processes showed convoluted regulation dynamics involving known cell cycle regulators like PCNA. Downregulation of mitochondrial enzymes, oxidative stress and damage to the mithochondrial inner membrane was early evidenced after a 6 hrs treatment and validated using a JC-1, a mitochondrial membrane potential probe. The resulting dataset gives us a first glimpse of the protein groups affected at the early stage of CYN cell intoxication.
Cianobactéria é o filo que mais se beneficia da crescente hipereutrofização das águas continentais. As florações de cianobactérias resultantes podem acumular potentes toxinas. A Cilindrospermopsina (CYN) é uma cianotoxina conhecida por inibir a síntese protéica e produzir estresse oxidativo, além de danos ao DNA em células eucarióticas. Os mecanismos moleculares e alvos de toxicidade aguda desta toxina ainda não são claros. Por esse motivo adoptamos uma abordagem de proteômica quantitativa baseada em descoberta para revelar as principais alterações nas células HepG2 em doses subletais de CYN (1 µM para 6, 12 e 24h). As proteinas dos hepatócitos foram marcadas metabolicamente, foram estimuladas com a toxina e os digestos trípticos foram analisados por espectrometria de massa em tandem de alta resolução (HRMS) no modo de aquisição dependente de dados. Escaneamos uma média de 4000 proteínas ao longo dos intervalos de tempo. A biosintese e transporte do colesterol foi inibida durante a maior parte do tratamento com a toxina. Proteínas e enzimas relacionadas com o processo de ubiquitinação (ex. UBE2L3) e proteólise (ex. PSMA2) foram inibidas, e alterações nas proteínas envolvidas nesses processos foram validadas por meio de Western Blot. Os processos de transcrição, tradução e ciclo celular mostraram uma dinâmica de regulação complexa, envolvendo reguladores e disruptores do ciclo celular como por exemplo PCNA. Danos à membrana mitocondrial e evidência de estresse oxidativo foram detectados após 6 horas de tratamento, e essas mudanças no proteoma foram validados por meio do corante JC-1 (test que detecta mudanças no potencial da membrana mitocondrial). O banco de dados resultante nos dá um primeiro vislumbre das proteinas afetados no estágio inicial da intoxicação celular pela CYN.

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9

Fituri, Hisham Saleh. "Synthesis of uracil containing precursors and analogues of cylindrospermopsin". Thesis, Bangor University, 2015. https://research.bangor.ac.uk/portal/en/theses/synthesis-of-uracil-containing-precursors-and-analogues-of-cylindrospermopsin(3d8eff07-e38b-4988-b4d6-b7942a797035).html.

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The thesis covers three topics: i) Synthesis of the uracil D-ring precursor of the cylindrospermopsin alkaloids: this study entailed the preparation of compounds I and II which were shown to be a RHS D-ring precursor in the synthesis of the cylindrospermopsin alkaloids. Compound I was prepared in 3 steps and in 24% overall yield from dibenzylurea whilst II was prepared from either diethyl 1,3-acetonedicarboxylate in 5 steps and 9% overall yield or barbituric acid in 5 steps and 16% overall yield. ii) Preparation of analogues of cylindrospermopsin: the synthesis of the cylindrospermopsin analogue III was achieved in 6 steps and 12% overall yield from the literature compound 2,6-dimethoxypyrimidine-4-carboxaldehyde. iii) Preparation and enzymatic studies on 2.4-dinitrobenzamide pro-drugs: the known pro-drugs IV (X = Cl, Br, I), were prepared and found to be good substrates for the enzyme NfsA NTR. These can thus be considered as alternative pro-drugs to the usually employed CB 1954 in combination with NfsA NTR for human chemotherapy.

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10

Thornhill, Andrew John. "Synthetic studies towards marine natural products". Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364987.

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11

Chandu, Vijith Cholakkal Parambil. "Investigation of novel methods to remove the cyanotoxin, Cylindrospermopsin, from drinking water". Thesis, Robert Gordon University, 2013. http://hdl.handle.net/10059/852.

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The widespread distribution of cyanobacteria and their toxic effects on humans has become a major concern for researchers. Cyanobacteria are a group of oxygenic phototrophic bacteria that exhibit an enormous diversity in shapes and arrangements and occupy widespread habitats that include brackish, marine and fresh water. The major concern among these organisms is not so much the cyanobacteria themselves but their toxin production. Under suitable circumstances, cyanobacteria can reach high biomass levels and form toxic algal blooms. These toxins, known as cyanotoxins, are produced as secondary metabolites by several cyanobacterial species. Cyanotoxins affect not only aquatic ecosystems but also impact on human health. The current work focuses on the cyanotoxin cylindrospermopsin that was originally known to be produced by the cyanobacterium species Cylindrospermopsis raciborskii but has since been identified in a number of other cyanobacterial species. Cylindrospermopsin is hepatotoxic and acts as a strong inhibitor of protein synthesis. The increasing occurrence of toxic cyanobacterial blooms is of major concern, particularly within drinking water supply systems. Therefore, the investigation of more effective water treatment technologies is of great importance in order to ensure the removal of these potent toxins. There are many techniques that have been used so far, but the need to use an effective and efficient method to remove the toxicity is paramount. Removal of the toxin by the use of microbial degradation has been evaluated. Experiments with different strains of bacterial isolates showed positive signs in the removal of toxin by Biolog MT2 assay. In addition to that shake flask culture experiments were carried out and did not show any significant removal of the toxin. Studies with natural water sources showed some pronounced effect on the removal of CYN. The use of TiO2 photocatalysis as another potential water treatment strategy was also evaluated. Current study successfully demonstrated the potential degradation of purified cylindrospermopsin using the titanium dioxide (TiO2) photocatalysis treatment method. TiO2 photocatalysis was performed by using a powder form (Degussa P25) catalyst effectively removing the toxin; however, the powder is difficult to remove from the treated water. TiO2 pellets (Hombikat K01/C) were found to be slower in degradation although they allowed for an easier adaption to a continuous treatment system. As an alternative Photospheres™ (buoyant glass beads coated in TiO2) was evaluated and showed the same efficacy as that of Degussa P 25. Studies were extended to investigate the application of UV-LEDs in the photocatalysis reaction to show better efficiency.

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12

Froscio, Suzanne M. "Investigation of the mechanisms involved in cylindrospermopsin toxicity : hepatocyte culture and reticulocyte lysate studies". Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phf938.pdf.

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Bibliography: leaves 121-139. The aim of this study was to determine the extent to which protein synthesis inhibition, lowered glutathione (GSH) levels and toxin metabolism contribute to the toxicity of cyclindrospermopsin. Both hepatocyte cultures and reticulocyte lysates were utilized as in vitro tools of investigation. The findings imply that the inhibition of protein synthesis by direct action of the toxin cannot be considered a primary cause of hepatocyte cell death over an acute time frame. Cytochrome P450-derived metabolites may play a crucial role in cytotoxicity, and the toxicity process does not appear to involve oxidative damage.

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13

Beers, Emily N. "Investigating the Effects of Temperature on the Growth and Toxin Production of Saxitoxin, Anatoxin and Cylindropsermopsin-Producing Cyanobacteria". Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1607677838514276.

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14

Havas, Fabien. "Studies towards a total synthesis of alkaloids manzamine A and cylindrospermopsin and development of a complex example of the Dowd-Beckwith rearrangement". Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1079983153.

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Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xviii, 465 p.; also includes graphics. Includes abstract and vita. Advisor: David J. Hart, Dept. of Chemistry. Includes bibliographical references (p. 253-262).

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15

Zhao, Cen. "Advanced Oxidation Processes of Problematic Toxin and Water Contaminants: Cylindrospermopsin, Iopamidol, 4-methylcyclohexane Methanol and Propylene Glycol Phenyl Ether". FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2235.

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The occurrences of cyanotoxin and organic contaminants threaten drinking water sources and are a serious human health and environmental concern. The control of these problematic contaminants and the remediation of the associated contaminants are critical for ensuring safe drinking water to significant populations. Advanced oxidation processes (AOPs) have received considerable attention as a potential water treatment for various pollutants. In this dissertation, advanced oxidative degradation of four problematic water toxic contaminants (CYN, iopamidol, 4-methylcyclohexane methanol and propylene glycol phenyl ether) were studied to develop the fundamental understanding required to assess AOPs as a potential water treatment process. UV and visible light activated (VLA) TiO2 photocatalysis using nitrogen and fluorine-TiO2 (NF-TiO2), phosphorus and fluorine-TiO2 (PF-TiO2) and sulfur-TiO2 (S-TiO2) were employed for degradation of 6-hydroxymethyl uracil (6-HOMU), a model compound for the potent cyanotoxin cylindrospermopsin (CYN). NF-TiO2 exhibits the most photoactive, followed by marginally active PF-TiO2 and inactive S-TiO2 under visible light irradiation. Our results indicate that O2-• plays an important role in VLA TiO2 photocatalysis. Fe (VI), an environmentally friendly oxidant, was employed for the degradation of CYN and 6-HOMU over a range of pH (7 ~ 9.5). The second order rate constants for the reaction of Fe (VI) with CYN decrease from 38.83 ± 0.07 M-1s-1 at pH 7 to 5.02 ± 0.04 M-1s-1 at pH 9.5. Fe (VI) mediated reactions primarily occur via oxidation of the uracil ring in CYN. ELISA results demonstrate that Fe (VI) oxidation process leads to a significant decrease in the bioactivity of CYN as a function of treatment time. Fe (III)-oxalate/H2O2 process was employed for the remediation of iopamidol, a model for ICM, to determine the formation rates and steady concentrations of •OH and O2-• under UV and visible light irradiation. Reduction by CO2-• and oxidation by •OH contribute to the degradation pathways. Pulse and gamma radiolysis of 4-methylcyclohexane methanol (MCHM) and propylene glycol phenyl ether (PPh) were studied to determine the bimolecular rate constants and reaction pathways. •OH addition to ortho and para positions in PPh are the predominant reaction pathways; H-abstraction are the primary reaction mechanisms for ∙OH mediated oxidation of MCHM

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16

Martínez, Ruiz Erika Berenice [Verfasser], Ulrich [Akademischer Betreuer] Szewzyk, Ulrich [Gutachter] Szewzyk y Sánchez Silvia [Gutachter] Pichardo. "Cylindrospermopsin transformation by manganese-oxidizing bacteria / Erika Berenice Martínez Ruiz ; Gutachter: Ulrich Szewzyk, Silvia Pichardo Sánchez ; Betreuer: Ulrich Szewzyk". Berlin : Technische Universität Berlin, 2021. http://d-nb.info/1231908564/34.

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17

He, Xuexiang. "Kinetic and Mechanistic Studies on the Removal of Cyanotoxins and Antibiotics with Hydroxyl and Sulfate Radical Based Advanced Oxidation Processes". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406881518.

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18

Zhang, Geshan. "The Degradation of Cyanotoxins by using Polymorphic Titanium Dioxide Based Catalysts". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406810827.

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19

Smith, Francine Mary Jorna. "Investigating Cyanotoxin Production by Benthic Freshwater Cyanobacteria in New Zealand". Thesis, University of Canterbury. Chemistry, 2012. http://hdl.handle.net/10092/6932.

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Cyanobacteria can form nuisance proliferations and produce large concentrations of toxins that pose a health hazard. This thesis investigates cyanotoxin production by New Zealand benthic cyanobacteria. Cyanobacteria were sampled from lakes, reservoirs, streams, and rivers. Thirty-five strains were isolated into culture and screened for genes involved in the biosynthesis of common cyanotoxins. Positive results were confirmed and cyanotoxin concentrations quantified using analytical chemistry techniques. Genes involved in anatoxin a/homoanatoxin a biosynthesis were detected in nine out of ten Phormidium cf. uncinatum strains isolated from a single mat. Anatoxin a was confirmed in these strains by LC–MS/MS at concentrations from 0.3 to 6.4 mg kg⁻¹. One strain also produced homoanatoxin-a. Anatoxin-a variation between strains may explain the wide range in anatoxin a concentrations previously observed in New Zealand. The sxtA gene involved in saxitoxin biosynthesis was identified in Scytonema cf. crispum strains. Saxitoxin was confirmed in strains and environmental samples by Jellett PSP Rapid Test and HPLC–FD. Gonyautoxins, neosaxitoxin, and decarbamoyl derivatives were also detected. This study is the first identification of these compounds in Scytonema and in New Zealand cyanobacterial strains. These strains were isolated from recreational and pre-treatment drinking water reservoirs, highlighting the risk benthic cyanobacteria pose to human and animal health. Experiments were undertaken using cultures of Phormidium and Scytonema to determine how growth influences cyanotoxin production. The effects of iron and copper stress on P. autumnale were also investigated. High iron concentrations disrupted attachment mechanisms. Iron and copper had a significant effect on growth, without significantly affecting anatoxin a production. However, the maximum anatoxin a quota was consistently observed during early exponential growth. Scytonema cf. crispum produced higher saxitoxin quota throughout exponential growth than during the stationary phase. Both the Phormidium and Scytonema growth experiments indicate that high toxin quota can be expected early in benthic mat development, making early detection of these proliferations important.

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20

Zajac, Meron Petro. "Investigação da cilidrospermopsina e PSPs em amostras de águas superficiais no Estado de São Paulo (OU) Investigação da presença de cilindrospermopsina e saxitoxinas em amostras de águas superficiais no Estado de São Paulo". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-27102009-120004/.

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O crescimento desordenado das cidades tem trazido à tona problemas de saneamento e degradação dos recursos naturais, entre eles a água. O despejo de efluentes domésticos e industriais têm ocasionado a eutrofização dos mananciais, culminando com a proliferação dos fitoplânctons. Esta proliferação tem chegado ao ponto, em certos momentos, de acarretar episódios de floração de algas. Entre os organismos fitoplanctônicos que se desenvolvem no ambiente, estão as cianobactérias, com vários gêneros capazes de produzir diversas cianotoxinas, tais como as microcistinas, anatoxinas, cilindrospermopsinas (CY), saxitoxinas (PSPs), entre outras. Com o aumento da freqüência dos episódios de floração de algas, a probabilidade da ocorrência destas toxinas também aumenta. Como conseqüência disto e devido às exigências legais, os corpos dágua devem ser monitorados para garantir a qualidade da água para consumo humano. Com vistas ao monitoramento da presença das cianotoxinas CY e PSPs, foram realizadas investigações em alguns corpos dágua do Estado de São Paulo. Das investigações realizadas, a neosaxitoxina foi identificada pela primeira vez no Reservatório Billings e os congêneres, saxitoxina, goniautoxina 2, goniautoxina 3, foram identificados de forma inédita em amostras de água deste reservatório. Com relação à CY, foi desenvolvido um método analítico, parcialmente validado. Entretanto, esta cianotoxina não foi localizada nas amostras de água ou cianobactérias das águas superficiais dos corpos dágua estudados. Este estudo mostra a importância do monitoramento da qualidade das águas dos mananciais quanto à presença de cianotoxinas, especialmente daqueles corpos dágua com a finalidade do consumo humano.
Cities growth usually occur in an unorganized manner. This tendence can generate a variety of sanitary problems, including the degradation of natural resources, such as water bodies. As a consequence, domestic and industrial efluents cause eutrofication of water reservoir, increasing the natural level of phytoplancton, what may form algal bloom. Among the phytoplanktonic organisms that grow in this modified environment it is found the cyanobacteria. Some of them can produce different types of cyanotoxins such as microcystin, anatoxin, cylindrospermopsin (CY) and saxitoxin (PSPs). The probability of production of these cyanotoxins increase according to frequent occurrence of algal blooms episodes. Consequently, water bodies monitoring becomes important to assure water quality. The aim of this project was to develop a specific method to identify the presence of cyanotoxins CY and to investigate PSPs in water bodies in São Paulo State. The results confirmed the presence of neosaxitoxin (NEO), a toxin of PSPs family. It was the first time that Neo was indentified in Billings Reservoir along with other PSPs types: saxitoxin, gonyautoxin 2, gonyautoxin 3. Although the study also included CY monitoring, CY was not identified in the tested samples. The present study confirmed the importance of continuous searching and monitoring of water bodies to grant quality to water used for human consumption.

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21

Norris, Ross L. G. "Toxicology of compounds from the cyanobacterium Cylindrospermopsis raciborskii /". [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16950.pdf.

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Hepp, Keli. "Composição, variação temporal e espacial de cianobactérias, com ênfase na espécie cylindrospermopsis raciborskii (woloszynska) seenayya & subba raju no lago do Parque Professor Theobaldo Dick, Lajeado, Rio Grande do Sul, Brasil". reponame:Repositório Institucional da UNIVATES, 2009. http://hdl.handle.net/10737/88.

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O desenvolvimento de florações de algas e cianobactérias vêm sendo cada vez mais frequente à medida que os ambientes aquáticos sofrem as interferências de ações antrópicas. Florações de cianobactérias são as principais responsáveis por problemas sanitários, devido ao potencial de produção de toxinas de certas espécies, além de conferir odor e coloração às águas. Tais fenômenos constituem sérios riscos à biota aquática e à comunidade associada, assim como à saúde pública. Em virtude da ocorrência de florações de cianobactérias no lago do Parque Professor Theobaldo Dick no município de Lajeado, Rio Grande do Sul, Brasil, possivelmente associada à mortandade de peixes documentada durante a floração, e por este se encontrar em uma área de preservação permanente, realizou-se uma avaliação da composição e da variação temporal e espacial de cianobactérias deste ecossistema. Foram analisadas 23 amostras durante os meses de fevereiro/2008 a janeiro/2009. As amostras de água foram obtidas mensalmente através da passagem de frasco na subsuperfície da água em dois pontos do lago. Foram analisadas as seguintes variáveis ambientais: temperatura do ar e da água (oC), pluviosidade (mm), transparência (m), pH, oxigênio dissolvido (mg.L-1), nitrogênio total (mg.L-1) e fósforo total (mg.L-1). A classe Cyanophyceae, objetivo deste estudo, esteve representada por 11 táxons, sendo Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju a espécie dominante durante o período estudado, com exceção do mês de janeiro/09 quando foi considerada abundante. A densidade (ind.mL-1) de cianobactérias representou 71,32% da densidade total verificada. A incidência destes organismos esteve relacionada às condições físico-químicas da água como consequência do lançamento de águas residuárias domésticas “in natura” no lago. Testes de toxicidade detectaram a presença de neurotoxinas, provavelmente associadas à morte de peixes registradas no lago.

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Guimarães, Hindria Renally Cavalcanti. "Avaliação da remoção de saxitoxina no tratamento de água de abastecimento em sistema convencional seguido de adsorção em carvão ativado granular (CAG)". Universidade Estadual da Paraíba, 2012. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/1916.

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The research aimed to evaluate the saxitoxin removal of the water supply in the conventional system followed by adsorption through granular activated carbon (GAC). The experiment was performed in three steps. In the first, coagulation diagrams were constructed for the aluminum sulfate. In the second stage, tests were conducted with aluminum sulfate and auxiliary coagulant (anionic and cationic polymers). In the third stage was carried conventional treatment (coagulation / flocculation /sedimentation / filtration) followed by adsorption on a column of granular activated carbon (GAC), in bench scale. The system was composed of a polypropylene plastic container for the storage of decanted water derived from the jar tests, with a capacity of 100 liters. The reservoir is connected via two peristaltic pumps with controlled flow for 1L/ h. Each pump is connected to two sand laboratory filters (SLF), which connected themselves to two columns of CAG, CC1 and CC2, with different coal granulometries. The system was monitored for 48 hours. The results of the coagulation tests showed good removal efficiency (>50%) for water of study (WS) at the natural pH of water (7.6), at a dosage of aluminum sulfate 25 mg/L, both in terms of turbidity and remaining true color. When evaluated the representability of the data, it was observed that the removal efficiency was not repeated. In the third stage, there was low saxitoxin removal by conventional treatment (7%), the removal was processed in the adsorption columns. CC1 and CC2 obtained removals ranging from 100 to 70%. However, for the maximum percentage removal CC2 removed greater amount of saxitoxin per unit time compared to CC1, nearly six hours of difference. The Langmuir and Freundlich isotherms showed better settings to the CC2 for the evaluated samples of activated carbon.
A pesquisa teve como objetivo principal avaliar a remoção de saxitoxina de água de abastecimento utilizando tratamento convencional seguido de adsorção por carvão ativado granular (CAG). O experimento foi realizado em três etapas. Na primeira, foram construídos diagramas de coagulação para o sulfato de alumínio. Na segunda etapa, foram realizados ensaios com sulfato de alumino e coagulantes auxiliares (polímeros aniônicos e catiônicos). Na terceira etapa foi realizado o tratamento convencional (coagulação/ floculação/ sedimentação/ filtração) seguido de adsorção em coluna de carvão ativado granular (CAG), em escala de bancada. O sistema esteve formado por um reservatório de plástico de polipropileno para o armazenamento de água decantada proveniente do jar tests, com capacidade para 100 litros. O reservatório foi interligado por intermédio de duas bombas peristálticas com vazão controlada para 1L/h. Cada bomba conectava-se a dois filtros de laboratório de areia (FLA), que se acoplavam a duas colunas de CAG, CC1 e CC2, com carvão de granulometrias distintas. O sistema foi monitorado durante 48h. Os resultados dos ensaios de coagulação mostraram boa eficiência de remoção (> 50 %) para água de estudo (AE) com pH natural da água (7,6), para uma dosagem de sulfato de alumínio de 25mg/L , tanto em termos de turbidez quanto de cor verdadeira remanescentes. Para os ensaios com polímeros sintéticos, o polímero catiônico, em geral, se destacou em relação ao polímero aniônico com percentuais médios de remoção de 57% para remoção de cor verdadeira. Quando avaliada a representabilidade dos dados, observou-se que as eficiências de remoções não se repetiram. Na terceira etapa, houve baixa remoção saxitoxina por parte tratamento convencional (7%), a remoção se processou nas colunas de adsorção. A CC1 e a CC2 obteram remoções entre 100 e 70%, entretanto, para percentuais máximos de remoção a CC2 removeu maior quantidade de saxitoxina por unidade de tempo em relação a CC1, praticamente seis horas de diferença. As isotermas de Freundlich e Langmuir para as amostras de carvão ativado avaliadas aprestaram melhores ajustes para a CC2.

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Dörr, Fabiane. "Efeito do herbicida glifosato sobre o crescimento e produção de metabólitos secundários em Microcystis aeruginosa e Cylindrospermopsis raciborskii". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-10062015-171941/.

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Cianobactérias, conhecidas por sua habilidade de sintetizar metabólitos com ação tóxica, podem se tornar dominantes em águas com altas concentrações de nitrogênio e fósforo. Embora a toxicidade do glifosato, o herbicida mais usado no mundo, em alguns organismos aquáticos seja conhecida, poucos estudos abordam o efeito desse composto sobre a produção de metabólitos secundários por cianobactérias. O objetivo deste trabalho foi avaliar a influência de diferentes concentrações de glifosato (produto técnico) sobre o crescimento e produção de cianotoxinas e microgininas pelas cepas brasileiras Microcystis aeruginosa LTPNA 08 e Cylindrospermopsis raciborskii CENA 302. Na presença de 15 mg/L de glifosato, o crescimento e a produção de toxinas pela M. aeruginosa foram reduzidos e de microgininas significativamente aumentada. Já a C. raciborskii, quando exposta à 20 mg/L de glifosato teve seu crescimento e síntese de clorofila-a, carotenoides e saxitoxinas aumentados. Concentrações superiores a 20 e 30 mg/L impediram o crescimento celular das cepas LTPNA 08 e CENA 302, respectivamente. A análise de ácidos graxos mostrou perfis bastante distintos entre as cepas. Na cepa LTPNA 08, enquanto que na presença de 10 mg/L de glifosato ocorreu diminuição do teor do ácido linoleico, o ácido estearidônico foi aumentado. Nenhuma das concentrações testadas promoveu alteração sobre o perfil de ácidos graxos da cepa CENA 302. A toxicidade de 5 produtos formulados a base de glifosato foi comparada ao produto técnico em ambas as linhagens-teste. Observou-se uma resistência distinta entre as cepas e toxicidade também variável entre as formulações comerciais. Sendo assim, diante da elevada resistência das cianobactérias M. aeruginosa e C. raciborskii ao glifosato, e considerando-se a elevada interferência antrópica através das práticas agrícolas, pode-se inferir que o uso excessivo e frequente desse herbicida é capaz de estimular o crescimento e dominância desses organismos, podendo modificar a estrutura e funcionalidade de ecossistemas aquáticos
Cyanobacteria, known for their ability to synthesize toxic metabolites, can become dominant in water bodies with high concentrations of nitrogen and phosphorus. Although the toxicity of glyphosate, the most widely used herbicide in the world, in some aquatic organisms is well known, few studies address the effect of this compound on the production of secondary metabolites by cyanobacteria. The aim of this study was to evaluate the influence of different concentrations the herbicide glyphosate (technical grade) on growth and production of cyanotoxins and microginins by Brazilian strains of Microcystis aeruginosa LTPNA 08 and Cylindrospermopsis raciborskii CENA 302. In the presence of 15 mg/L of glyphosate, growth and toxin production by M. aeruginosa were reduced and microginins cell quota significantly increased. The C. raciborskii strain, when exposed to 20 mg/L of glyphosate, had the growth, and chlorophyll-a, carotenoids and saxitoxins production increased. Concentrations above 20 and 30 mg/L prevented cell growth of LTPNA 08 and CENA 302 strains, respectively. Fatty acid analysis showed distinct profiles among the strains. When exposed to 10 mg/L of glyphosate, a decrease in the linoleic acid and increase in stearidonic acid content were observed in M. aeruginosa LTPNA 08 strain. None of the tested concentrations of glyphosate promoted change on the fatty acid profile of CENA 302 strain. The toxicity of 5 glyphosate formulated products was compared to technical product to both strains. There was a distinct resistance among strains and also a variable toxicity among formulated products. Thus, given the high glyphosate resistance of M. aeruginosa and C. raciborskii cyanobacteria, and considering the high anthropogenic interference through agri cultural practices, it can be inferred that excessive and frequent use of this herbicide is able to stimulate growth and dominance of these organisms, which may modify the structure and function of aquatic ecosystems

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Buch, Bruna [UNESP]. "Ecofisiologia de morfotipos reto e espiralado de Cylindrospermopsis raciborskii (Cyanobacteria) em condições controladas". Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/87891.

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Cylindrospermopsis raciborskii é uma espécie formadora de florações potencialmente tóxicas em sistemas aquáticos eutrofizados, inclusive naqueles utilizados para abastecimento público, podendo trazer riscos à saúde humana. Esta espécie apresenta morfologia do tricoma reto, sigmóide e espiralado, sendo que as razões para esta variação ainda não foram claramente definidas. Estudos comparativos de seqüências genéticas têm demonstrado que a morfologia não está relacionada à filogenia do gênero Cylindrospermopsis e que os diferentes morfotipos representam uma única espécie. Os objetivos deste estudo foram: avaliar os efeitos de duas diferentes intensidades luminosas (30 e 90 μmol.m-2.s-1) e temperaturas (21 e 31°C) no crescimento e na morfologia de tricomas de uma linhagem reta (ITEP28) e outra espiralada (ITEP31) e, testar a hipótese de que ambos os morfotipos respondam negativamente à intensidade luminosa e temperatura altas. As linhagens reta e espiralada apresentaram pequenas diferenças na morfometria celular nas diferentes condições testadas. Além disso, a linhagem espiralada apresentou alterações na morfologia do tricoma, mostrando uma plasticidade fenotípica maior em relação à linhagem reta. Ambas as linhagens se adaptaram às condições testadas, embora a linhagem reta tenha apresentado velocidades máximas (V(x)= 3,21; 3,63; 3,89) de crescimento maiores que a linhagem espiralada (V(x)= 0,97; 1,07; 1,61; 1,80). Na condição de 90 μmol.m-2.s-1 e 21°C, a linhagem reta não atingiu a fase exponencial do crescimento, enquanto a linhagem espiralada demorou para atingir a velocidade máxima de crescimento, e este foi interrompido antes. Nas condições de temperatura baixa (21°C) não houve produção de acinetos. Além disso, esta condição de temperatura baixa aliada a intensidade luminosa alta (90 μmol.m-2.s-1) prejudicou o crescimento de ambas...
Cylindrospermopsis raciborskii is a potentially toxic bloom former species in eutrophic aquatic systems, including water supply reservoirs where it can bring risks to human health. This species shows straight, sigmoid and coiled trichome morphology and the reasons to this variation aren’t clarified yet. Comparative studies of genetic sequences have been indicated that morphology isn’t related with the Cylindrospermopsis genus phylogeny, thus the different morphotypes represents a single species. The aims of this study were: to evaluate the effects of two different light intensities (30 and 90 μmol.m-2.s-1) and temperatures (21 and 31°C) on growth and morphology of straight (ITEP28) and coiled (ITEP31) morphotypes and, to test the hypothesis that both morphotypes respond negatively to the high light intensity and temperature. The straight and coiled morphotypes showed a little difference in the cell width and length measurements in the tested conditions. Moreover, the coiled trichome exhibited morphological changes that indicated greater phenotipical plasticity than the straight one. Both strains were adapted to the tested conditions, although the straight one showed higher growth velocity (V(x)= 3,21; 3,63; 3,89) than the coiled one (V(x)= 0,97; 1,07; 1,61; 1,80). In the condition of 90 μmol.m-2.s-1 and 21°C, the coiled morphotype delays to reach the maximum growth velocity, thus the growth was interrupted before that. In the conditions of low temperature (21°C) there is no akinetes production. Furthermore, this condition of low temperature associated with high light intensity (90 μmol.m-2.s-1) harmed the growth of both morphotypes. Therefore, the results found opposed to the considered hypothesis that both morphotypes are susceptible to the high light intensity and temperature in culture controlled conditions, since both morphotypes reached the highest growth velocity... (Complete abstract click electronic access below)

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Melo, Ana Elisa Silva de. "Avaliação da filtração lenta na remoção de células de Cylindrospermopsis raciborskii e saxitoxinas". reponame:Repositório Institucional da UnB, 2006. http://repositorio.unb.br/handle/10482/6464.

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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2006.
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O presente trabalho apresenta uma avaliação do desempenho da filtração lenta na remoção de células viáveis de Cylindrospermopsis raciborskii e de saxitoxinas na água para consumo humano. Também foi realizada uma investigação preliminar da potencialidade da pré-filtração ascendente em pedregulho como sistema de pré-tratamento para a filtração lenta no tratamento de águas com elevada presença de células de C. raciborskii. O trabalho foi desenvolvido em escala piloto, e divido em duas etapas experimentais. Na 1ª Etapa Experimental, a instalação piloto era constituída por um sistema de filtração lenta, composto por dois filtros lentos operando em paralelo. Já na 2ª Etapa Experimental, foi adicionada à instalação piloto uma unidade de pré-filtração ascendente em pedregulho precedendo os filtros lentos. Os filtros lentos foram operados com taxa de filtração de 3m3/m2.dia e o pré-filtro ascendente em pedregulho com taxa de filtração de 10m3/m2.dia. Durante a 1ª Etapa Experimental, foi avaliado o desempenho dos filtros lentos quando alimentados com água bruta (lago Paranoá) inoculada com diferentes concentrações de células de C. raciborskii (105 a 6x106céls./mL) ou saxitoxinas extracelulares (3μg/L). De acordo com os resultados obtidos, o processo de filtração lenta foi bastante eficiente na remoção de células de C. raciborskii com concentrações da ordem de 105 céls./mL. Entretanto, para as concentrações mais elevadas de C. raciborskii (acima de 1x106 céls./mL), a filtração lenta como única etapa de tratamento não se apresentou como alternativa mais apropriada, pois permite o traspasse de turbidez, clorofila-a, saxitoxinas intra e extracelulares, além de apresentar acelerado desenvolvimento da perda de carga. Nos períodos de traspasse, ocasionados pelo carreamento de células de C. raciborskii previamente retidas no meio filtrante, os filtros lentos produziram efluentes com valores de turbidez, clorofila-a, saxitoxinas intracelulares em torno de 2UT, 10μ/L e 5μg/L, respectivamente. Foi detectada a presença de saxitoxinas extracelulares na água filtrada quando o filtro lento era alimentado com 106 céls./mL de C. raciborskii, confirmando a ocorrência de lise de parte das células retidas no meio filtrante. Foi também observado um impacto negativo da presença de saxitoxinas na água bruta sobre a remoção de coliformes. Os resultados da 2ª Etapa Experimental sugerem que pré-filtração antecedendo a filtração lenta apresenta grande potencial de aplicação no tratamento de águas com elevadas concentrações de células de C. raciborskii (acima de 106 céls./mL). O pré-filtro ascendente em pedregulho conseguiu remover parte das células de C. raciborskii presentes na água bruta produzindo efluentes capazes de evitar o desenvolvimento acelerado da perda de carga nos filtros lentos. Diferentemente do observado com o uso de filtro lento como unidade única de tratamento, a turbidez, o teor de clorofila-a e saxitoxinas totais (intra + extracelulares) dos efluentes dos filtros lentos se mantiveram abaixo de 0,3UT, 2μg/L e 0,2μg/L, respectivamente, mesmo quando a água bruta que alimentava o sistema apresentava concentrações de células de C. raciborskii muito elevadas (7x106 céls./mL). Entretanto, a remoção de turbidez e clorofila-a no pré-filtro ascendente em pedregulho apresentaram valores abaixo dos verificados para essa unidade na literatura. Dessa forma, faz-se necessário a realização de estudos para otimização dos parâmetros de projeto e operação da unidade de pré-filtração. ______________________________________________________________________________ ABSTRACT
This work presents an evaluation of the performance of the slow sand filtration in the removal of viable cells of Cylindrospermopsis raciborskii and extracellular saxitoxin from raw water. Also, it was carmed out a preliminary investigation on the use of the upflow roughing filtration as pretreatment stage for slow sand filtration in treatment of raw water with very high concentration Cylindrospermopsis raciborskii cells. The work was developed in a pilot scale and was carried out in two experimental stages. In the first stage, the pilot plant comprises two slow sand filtration units operated in parallel. In the second stage, an upflow rough filter was installed before the slow sand filters. The slow sand filters were operated at filtration rate of 3m3/m2.day and the upflow rough filter at filtration rate of 10m3/m2.day. During the 1st stage, the slow sand filters were fed with raw water (Paranoá lake water) spiked with different concentrations of a cultived toxic strain C. raciborskii (105 to 6x106cells/mL) or with extracellular saxitoxins (3μg/L). Based on the results, the process of slow sand filtration is very efficient in the removal of cells of C. raciborskii in the range of 105cells/mL. However, for a raw water with higher concentrations of cells of C. raciborskii (>1x106 cells/mL), the slow sand filtration as sole treatment step don’t seems to be the adequate alternative of treatment, once it was observed the occurrence of turbity, chlorophyll-a, intra and extracellular saxitoxins breakthrough. Furthermore a high head-loss development was observed during the filtration process. Breakthrough occurred mainly as a result of detachment of part of the cells previously retained in the filter. During breakthrough periods the slow sand filters produce effluents with concentration of turbity, chlorophyll-a and intracellular saxitoxins higher than 2NTU, 10μg/L and 5μg/L, respectively. When the presence of saxitoxins in the raw water was mostly in the intracellular fraction, raw water with 106cells/mL of C. raciborskii, it was detected presence of extracellular saxitoxins in the filtered water, confirming that cells lyses was occurring in the filter bed. It was confirmed that presence of saxitoxins in the raw water has a negative impact in the removal of coliforms. The results of the 2nd stage suggest that the use of upflow filter before the slow sand filtration shows great potential for the treatment of waters with high concentrations of cells of C. raciborskii (higher than 1x106 cells/mL). The upflow rough filter was able to prevent the high rate of the head-loss development in the slow sand filters that was observed in the 1st stage. The use of the roughing filtration as pretreatment for the slow sand filters allowed these units to produce effluents with turbity, chlorophyll-a and total saxitoxins (intra+extracellular) lower than 0,3NTU, 2μg/L e 0,2μg/L, respectively, even when the concentration of C. raciborskii in the raw water was 7x106cells/mL. However, the removal efficiency of turbity and chlorophyll-a in the upflow rough filter was lower than that reported in the literature. Thus, future studies aiming the optimization of project and operational parameters must be pursued.

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Buch, Bruna. "Ecofisiologia de morfotipos reto e espiralado de Cylindrospermopsis raciborskii (Cyanobacteria) em condições controladas /". Rio Claro : [s.n.], 2009. http://hdl.handle.net/11449/87891.

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Orientador: Maria do Carmo Bittencourt de Oliveira
Banca: Carlos Eduardo de Mattos Bicudo
Banca: João Dias de Toledo Arruda Neto
Resumo: Cylindrospermopsis raciborskii é uma espécie formadora de florações potencialmente tóxicas em sistemas aquáticos eutrofizados, inclusive naqueles utilizados para abastecimento público, podendo trazer riscos à saúde humana. Esta espécie apresenta morfologia do tricoma reto, sigmóide e espiralado, sendo que as razões para esta variação ainda não foram claramente definidas. Estudos comparativos de seqüências genéticas têm demonstrado que a morfologia não está relacionada à filogenia do gênero Cylindrospermopsis e que os diferentes morfotipos representam uma única espécie. Os objetivos deste estudo foram: avaliar os efeitos de duas diferentes intensidades luminosas (30 e 90 μmol.m-2.s-1) e temperaturas (21 e 31°C) no crescimento e na morfologia de tricomas de uma linhagem reta (ITEP28) e outra espiralada (ITEP31) e, testar a hipótese de que ambos os morfotipos respondam negativamente à intensidade luminosa e temperatura altas. As linhagens reta e espiralada apresentaram pequenas diferenças na morfometria celular nas diferentes condições testadas. Além disso, a linhagem espiralada apresentou alterações na morfologia do tricoma, mostrando uma plasticidade fenotípica maior em relação à linhagem reta. Ambas as linhagens se adaptaram às condições testadas, embora a linhagem reta tenha apresentado velocidades máximas (V(x)= 3,21; 3,63; 3,89) de crescimento maiores que a linhagem espiralada (V(x)= 0,97; 1,07; 1,61; 1,80). Na condição de 90 μmol.m-2.s-1 e 21°C, a linhagem reta não atingiu a fase exponencial do crescimento, enquanto a linhagem espiralada demorou para atingir a velocidade máxima de crescimento, e este foi interrompido antes. Nas condições de temperatura baixa (21°C) não houve produção de acinetos. Além disso, esta condição de temperatura baixa aliada a intensidade luminosa alta (90 μmol.m-2.s-1) prejudicou o crescimento de ambas... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Cylindrospermopsis raciborskii is a potentially toxic bloom former species in eutrophic aquatic systems, including water supply reservoirs where it can bring risks to human health. This species shows straight, sigmoid and coiled trichome morphology and the reasons to this variation aren't clarified yet. Comparative studies of genetic sequences have been indicated that morphology isn't related with the Cylindrospermopsis genus phylogeny, thus the different morphotypes represents a single species. The aims of this study were: to evaluate the effects of two different light intensities (30 and 90 μmol.m-2.s-1) and temperatures (21 and 31°C) on growth and morphology of straight (ITEP28) and coiled (ITEP31) morphotypes and, to test the hypothesis that both morphotypes respond negatively to the high light intensity and temperature. The straight and coiled morphotypes showed a little difference in the cell width and length measurements in the tested conditions. Moreover, the coiled trichome exhibited morphological changes that indicated greater phenotipical plasticity than the straight one. Both strains were adapted to the tested conditions, although the straight one showed higher growth velocity (V(x)= 3,21; 3,63; 3,89) than the coiled one (V(x)= 0,97; 1,07; 1,61; 1,80). In the condition of 90 μmol.m-2.s-1 and 21°C, the coiled morphotype delays to reach the maximum growth velocity, thus the growth was interrupted before that. In the conditions of low temperature (21°C) there is no akinetes production. Furthermore, this condition of low temperature associated with high light intensity (90 μmol.m-2.s-1) harmed the growth of both morphotypes. Therefore, the results found opposed to the considered hypothesis that both morphotypes are susceptible to the high light intensity and temperature in culture controlled conditions, since both morphotypes reached the highest growth velocity... (Complete abstract click electronic access below)
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Merel, Sylvain. "Caractérisation des sous-produits de chloration de la microcystine-LR et de la cylindrospermopsine". Phd thesis, Université Rennes 1, 2009. http://tel.archives-ouvertes.fr/tel-00472435.

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La présence de prolifération de cyanobactéries et des toxines associées dans les eaux de surface utilisées pour la production d'eau potable est une problématique de santé publique majeure car plusieurs cas d'intoxication ont été rapportés. Il s'avère donc nécessaire de comprendre le comportement des cyanotoxines au sein des filières de traitement d'eau et en particulier vis-à-vis de la chloration, procédé de désinfection le plus répandu en France. Les travaux réalisés au cours de cette thèse portent sur la chloration de la cyanotoxine la plus commune et d'une cyanotoxine émergente en Europe : la microcystine-LR et la cylindrospermopsine. La réaction du chlore avec les toxines a été caractérisée et divers sous-produits ont été identifiés grâce à la spectrophotométrie ultraviolet et la spectrométrie de masse à haute résolution. Des tests réalisés sur la bactérie Vibrio fischeri et sur des cellules Caco-2 ont ensuite permis de vérifier l'impact de la chloration sur la toxicité du milieu.

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Pengelly, Jasper John Lobl Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "Molecular characterisation of membrane transporters associated with saxitoxin biosynthesis in cyanobacteria". Publisher:University of New South Wales. Biotechnology & Biomolecular Sciences, 2008. http://handle.unsw.edu.au/1959.4/41429.

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The release of the neurotoxic alkaloid saxitoxin by cyanobacterial cells was previously thought to occur primarily after cell lysis, yet recent evidence also suggests active toxin export by membrane transporters. Transporter proteins associated with STX biosynthesis in Cylindrospermopsis raciborskii T3 (sxtF and sxtM) and Anabaena circinalis 131C (naDt) were predicted to be involved in the export of STX from cyanobacterial cells. The main aim of this project was to characterise the transporters associated with STX biosynthesis, by investigation of their genetic prevalence, functional substrates and specific regulation. An sxtM homologue was discovered in A. circinalis 131C, as part of an sxt cluster, and found to be uniquely associated with STX-producing strains. Bioinformatic and phylogenetic analysis showed that the translated sxt transporters clustered with the NorM prokaryotic MATE sub-family and membrane topology analysis predicted 12 membrane-spanning regions. To characterise the functional substrates of the putative STX-transporters, they were heterologously expressed in the antibiotic-sensitive E. coli strain KAM32. Expression of the sxt MATES complemented host sensitivity to the cationic fluroquinolone antibiotics, ciprofloxacin and ofloxacin. Disruption of gene homologues of naDt and the sxt MATE genes in Synechocystis sp. PCC6803 yielded mutant strains with increased sensitivity to the toxic organic cations, methyl viologen and acriflavine. Transcription of the putative STX transporters, and the putative STX biosynthesis gene sxtA, was studied in C. raciborskii T3 and A. circinalis 131C under alkali and Na+ stress. Alkali stress (pH 9) decreased total STX levels in A. circinalis 131C and was correlated with a down-regulation of the putative transport and biosynthetic genes. In C. raciborskii T3, alkali stress promoted higher extracellular but lower intracellular STX levels, which also correlated with large increases in transcription of the putative STX transport genes.

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Cavaliere, Rosalia Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "The regulation of Saxitoxin production in Cyanobacteria". Publisher:University of New South Wales. Biotechnology & Biomolecular Sciences, 2008. http://handle.unsw.edu.au/1959.4/44403.

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Aquatic microalgae produce a variety of toxic secondary metabolites, which are a concern for public health and seafood industries, while also presenting a source of pharmacologically valuable compounds. The present study deals with the physiology and molecular genetics of saxitoxin (STX), a cyanobacterial neurotoxic alkaloid. Ecological and chemical parameters have been investigated for their effects on growth and STX production in the cyanobacterium Cylindrospermopsis raciborskii T3, in order to better understand the physiological responses of this cyanobacterium to the anthropogenic eutrophication of water bodies. The results indicated that phosphate, in particular, had an incremental effect on STX production, as well as promoting the up-regulation of transcription of the STX biosynthetic gene cluster (sxt). High temperature was found to negatively affect growth and STX production in this organism. The effects of the plant hormone, jasmonic acid, were also tested, since it has previously been shown to affect plant alkaloid production. The hypothesised similarity between cyanobacterial and plant secondary metabolism in response to this plant hormone was confirmed in the neurotoxic cyanobacterium, C. raciborskii T3, as well as the non-toxic Anabaena sp. PCC7120. Furthermore, investigation of the sxt gene cluster transcriptional map in C. raciborskii T3 was carried out, with identification of three main polycistronic and one monocistronic transcripts. Promoter regions putatively involved in the regulation of STX production in C. raciborskii T3 were also identified. Transcription factor consensus motifs, the pho boxes, were identified in the main promoter region. These conserved motifs are the binding regions for the transcriptional regulator, PhoB, to the pho regulon genes, involved in phosphate uptake during conditions of its depletion in the environment. Moreover, a genomic region adjacent to the sxt gene cluster in C. raciborskii T3 was identified and characterised, putatively encoding a regulatory two-component system. This system appears to be involved in the sensing of environmental signals, in particular depleted phosphate, while activating the transcription of genes involved in its uptake and transport. The results of this study lead to a greater understanding of the complex factors associated with the regulation of STX biosynthesis and bloom-formation, by the cyanobacterium C. raciborskii T3.

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Galvanese, Elena Fukasawa. "Concomitant acclimation of Cylindrospermopsis raciborskii to temperature and phosphate deficiency reveals distinct strain plastic responses". reponame:Repositório Institucional da UFPR, 2017. http://hdl.handle.net/1884/46017.

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Orientador : Prof. Dr. André Andrian Padial
Coorientador : Prof. Dr. Luis Aubriot
Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Ecologia e Conservação. Defesa: Curitiba, 03/03/2017
Inclui referências : f. 29-32
Área de concentração
Resumo: Cylindrospermopsis raciborskii é uma das cianobactérias potencialmente tóxica mais estudada. Efeitos de fatores isolados como aumento da temperatura ou desta combinada com luz têm sido descritos como promotores do crescimento de C. raciborskii. Entretanto, ainda não foi descrita a combinação entre deficiência de nutrientes e temperatura. Neste trabalho, as performances de duas cepas de C. raciborskii (MVCC19, uruguaia e LP1, brasileira) foram avaliadas sob aclimatação à mudanças de temperaturas (25°C-32°C) e duas transições de suficiência a deficiência de fósforo. Quando sujeita à transição de alta suficiência à deficiência, somente as cepas aclimatadas à alta temperatura cresceram. A cepa MVCC19 mostrou maior taxa de crescimento e reduzida fase curva de crescimento em relação a LP1. Diferenças morfológicas também foram encontradas: MVCC19 cresceu em número de filamentos menores, enquanto LP1 aumentou não só o número de filamentos como também o comprimento e número de células por filamento ao final da fase exponencial. Nós hipotetizamos que atributos ecofisiológicos e morfológicos das cepas podem refletir as condições dos lagos de origem. LP1 foi isolada de um lago oligo-mesotrófico, o que provavelmente explica sua otimização sob deficiência de fósforo; já crescimento explosivo e menores filamentos de MVCC19 podem refletir condições eutróficas e de alta turbidez. OO efeito positivo da aclimatação à elevada temperatura pode ser consequência da redução do quota celular mínimo, permitindo aos organismos ajustar e superar a depleção de fosfato nos lagos. Palavras-chave: cianobactéria, resposta funcional, ecótipos, lago, fisiologia de alga, funcionamento de ecossistema.
Abstract: Cylindrospermopsis raciborskii is one of the most studied potentially harmful cyanobacteria. Effects of single factors like increased temperature or combined with light have been described as promoters of C. raciborskii growth. However, until now it was not described for cyanobacteria the combined effects of nutrient deficiency and temperature. Here, the performances of two strains of C. raciborskii (MVCC19, Uruguayan and LP1, Brazilian) were evaluated under acclimation to temperatures shifts (25ºC - 32ºC) and two transitions from phosphorus (P) sufficiency to deficiency. When subjected to the transition from high P sufficiency to deficiency state, only the temperature acclimated strains developed. The MVCC19 strain showed higher growth rate and less prolonged growth phase than LP1. Also morphologically differences were found: MVCC19 strain grew by production of shorter filaments, while LP1 strain increased in length and number of cells per filament at the end of the exponential phase. We hypothesized that ecophysiological and morphological traits of the strains may reflect the originary lake conditions. The LP1 strain was isolated from an oligo to mesotrophic lake, which probably explains its optimization of growth under phosphorus deficiency. The explosive growth and shorter trichomes of MVCC19 may reflect more eutrophic and turbid lake conditions. The positive effect of previous acclimation to elevated temperature may be consequence of the reduction of minimal internal cellular quota, allowing the organisms to adjust and overcome the phosphate depletion in lakes. Key-words: cyanobacteria, functional response, ecotypes, lake, algae physiology, ecosystem functioning.

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Oliveira, Otávio Gomes de. "Desenvolvimento de um equipamento óptico para o estudo do movimento vertical de cianobactérias – Cylindrospermopsis raciborskii". Universidade Federal de Juiz de Fora (UFJF), 2007. https://repositorio.ufjf.br/jspui/handle/ufjf/3948.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A Cylindrospermopsis raciborskii está entre as principais espécies observadas nas florações de cianobactérias no Brasil. Como essa espécie é potencialmente tóxica, podendo produzir hepatotoxinas e neurotoxinas, a formação de florações constitui um sério problema de interesse público, inclusive, no Brasil. A ocorrência de florações torna muito alto o custo de tratamento da água para consumo humano e, além disso, não existem hoje métodos eficientes para remoção das cianotoxinas da água. Por constituir um problema relevante para toda a sociedade, é imprescindível descrever qualitativa e quantitativamente as respostas desses organismos a fatores externos. Não considerando-se apenas uma situação real, mas também isolando fatores e buscando estabelecer em qual medida cada um deles determina o comportamento dessas cianobactérias. Neste trabalho, foi desenvolvido um equipamento automatizado, de bancada, para ser usado em experimentos que tratem das respostas de cianobactérias ao meio ambiente via regulação de flutuabilidade. Esse equipamento descreve o perfil de distribuição de organismos ao longo de um tubo contendo amostra. Ele pode ser configurado para monitorar essa distribuição ao longo do tempo. Com isso, é possível sujeitar os organismos a algum fator de interesse e avaliar as alterações nas concentrações dos organismos em função da profundidade.
Cylindrospermopsis raciborskii is among the most common species observed in cyanobacterial blooms in Brazil. Since this species is potentially toxic (it can produce hepatotoxins and neurotoxins), blooms formation constitute by itself a serious problem, of interest to all the society, including Brazil. The occurrence of cyanobacterial blooms makes the costs of water treatment for human use very expensive. Furthermore, there are no efficient methods nowadays for removing the cyanotoxins from water. Because it is a relevant problem to all the society, it is important to describe quantitatively and qualitatively the responses these organisms have to external factors. Not only considering a real situation, but also trying to isolate factors and establish how important each of them is in determining the behavior of these cyanobacteria. In this work, a fully automatic system is developed to be used in laboratory experiments that focus on the responses of cyanobacteria to the environment via the floating regulation mechanism. This set can describe how the organisms are distributed along the tube which contains the sample. It can be configured to monitor this distribution periodically, so that it is possible to subject the organisms to some external factor of interest and to assess the changes over time in the concentration of organisms as a function of the depth in the water column.

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33

Giraldi, Laís Albuquerque. "Efeitos da concentração de micronutrientes no crescimento e na produção de saxitoxina em Cylindrospermopsis raciborskii". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-19012015-102222/.

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A espécie de cianobactéria Cylindrospermopsis raciborskii vem se destacando na literatura atual devido à sua presença e dominância em lagos e reservatórios em diversas regiões do planeta e a principal preocupação deste cenário é por ela ser potencialmente tóxica. Estudos revelaram que o crescimento e a síntese de toxinas em espécies de microrganismos fitoplanctônicos estão atrelados à limitação ou excesso de micronutrientes, porém, ainda são desconhecidos os efeitos desta variação na produção de saxitoxina (STX) por C. raciborskii. Para contribuir com o esclarecimento desta questão, investigou-se o efeito de diferentes concentrações dos micronutrientes Fe, Zn, Cu, Mn, Co e B no crescimento e na produção de STX de uma linhagem de C. raciborskii. Em salas climatizadas, culturas desta linhagem foram expostas durante 20 dias a 5 concentrações de cada micronutriente, com alteração do meio de cultura ASM-1. As respostas fisiológicas de C. racibosrkii a estas modificações foram verificadas através da velocidade máxima de crescimento (μmáx), rendimento do biovolume, tempo de duplicação (Td), concentração de clorofila a, assimilação de nitrato e ortofosfato e síntese de STX total (intra e extracelular). As maiores concentrações de STX por biovolume (STX/biovolume) foram obtidas nos tratamentos com baixa concentração de Fe (0,4 μM) e elevada concentração de Cu (0,8 μM). Nos micronutrientes Zn, Co e B, houve uma tendência de redução da síntese de STX nas maiores concentrações destes metais. Enquanto as concentrações extremas de Fe e Mn inibiram o crescimento (Fe: 0,4 e 400 μM e Mn: 0,7 e 600 μM), as concentrações centrais favoreceram (Fe: 4 a 60 μM e Mn: 7 a 200 μM). Elevada concentração de Cu (0,8 μM) causou aumento de 2,6 vezes (160%) do volume celular e redução na síntese de clorofila a, sem alterações significativas em μmáx e rendimento. O aumento da concentração dos micronutrientes Fe, Zn, Mn e B no meio de cultura causaram maior assimilação de ortofosfato por biovolume (P/biovolume). Estes principais resultados demonstraram que os micronutrientes afetam a síntese de STX e o crescimento de C. raciborskii, podendo ser associados aos diversos mecanismos de captura e detoxificação de metais que as cianobactérias possuem. Embora as extrapolações dos resultados laboratoriais para o ambiente devam ser realizadas com prudência, estudos relacionados à ecofisiologia de cianobactérias como este, são fundamentais para análise criteriosa de cada variável podendo ser utilizado como ferramenta de diagnóstico e prevenção de florações tóxicas.
Cylindrospermopsis raciborskii has been highlighted in several researches due to the dominance in many lakes and reservoirs around the world, the main concern about it due to the ability to produce toxins. Studies have revealed that growth and toxins production in phytoplankton species are linked to micronutrients limitation or excess. Nevertheless, micronutrient variation effects on saxitoxin (STX) production by C. raciborskii are still unknown. To contribute to clarify this issue, we investigated the effect of different micronutrients concentration, such as Fe, Zn, Cu, Mn, Co and B, on the growth and saxitoxin production of C. raciborskii strain. In climatized growth room, the cultures of C. raciborskii strain were exposed to 5 different concentration of each micronutrient, present in ASM-1 medium, during 20 days. The C. racibosrkii physiological responses was detected through maximum growth rate (μmáx), biovolume yield, doubling time (Td), chlorophyll-a, nitrate and orthophosphate assimilation and the total STX production (intra and extracellular). The higher concentrations of STX per biovolume (STX/biovolume) were observed in treatments with low Fe concentration (0.4 μM) and high Cu concentrations (0.8 μM). Higher concentrations of Zn, Co and B lead to low STX production. While the Fe and Mn extreme concentrations inhibited the growth (Fe: 0.4 and 400 μM and Mn: 0.7 to 600 μM), the central concentrations favored (Fe: 4 to 60 μM, and Mn: 7-200 μM). A high Cu concentration (0,8 μM) leads to 2,6 fold increase (160%) in cellular volume and decrease the chlorophyll-a content, however máx and biovolume yield did not change. Increasing the Fe, Zn, Mn and B concentration in the culture caused higher assimilation of orthophosphate per biovolume (P/biovolume). These results indicated that micronutrients affected C. raciborskii growth and STX production, and may be associated with the diverse cyanobacterial mechanisms of metals capture and detoxification. Cyanobacteria ecophysiology studies, as this research, are fundamental to careful analysis of each variable, which could be used as diagnostic and a tool to prevention of toxic blooms.

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Noyma, Natália Pessoa. "Avaliação da ultraestrutura e morte celular em Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju (Cianobacteria) sob efeito da radiação ultravioleta". Universidade Federal de Juiz de Fora (UFJF), 2009. https://repositorio.ufjf.br/jspui/handle/ufjf/4520.

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A radiação solar é essencial para a vida na Terra, fornecendo energia para a fotossíntese e calor. Do total da radiação que tinge o planeta, 9% é representada pela a radiação ultravioleta (UV). Estudos com grupos de cianobactérias mostram efeitos negativos de radiação UV em processos fisiológicos, como crescimento e sobrevivência e alterações de enzimas relacionadas ao metabolismo de nitrogênio e fixação de CO2. Cylindrospermopsis raciborskii é uma cianobactéria filamentosa fixadora de nitrogênio que vem se tornando uma das espécies de cianobactérias de maior interesse de pesquisadores devido a sua potencial toxicidade e sua elevada adaptabilidade ecofisiológica. Neste trabalho, investigou-se o efeito da radiação UV A, UV-B e UV (A+B) na densidade, viabilidade celular e ocorrência de alterações morfológicas por microscopia eletrônica de transmissão. Foram usadas intensidades naturais sobre a cepa de C. racirborskii no período de 6 horas de tratamento. Os tratamentos UV-A e UV (A+B) apresentaram efeitos negativos significativos na densidade e integridade de membrana (99,3 e 95% de células mortas, respectivamente), enquanto UV-B não apresentou diferença significativa na densidade, mas induziu alteração de integridade da membrana em 57% das células no final do tratamento. Análises ultraestruturais demonstraram modificações morfológicas em todos os tratamentos caracterizadas principalmente por redução da proporção de tilacóides e estruturas de armazenamento de pigmentos acessórios. Nossos resultados demonstram a indução de morte celular significativa em cepa de C. racirborskii pelos tratamentos UV-A e UV (A+B). Entretanto, o tratamento UV-B parece ser menos letal para esta cepa na intensidade usada. O entendimento de processos de morte celular em populações fitoplactônicas induzida por radiação UV (A+B) abre novas perspectivas sobre a influência deste tipo de radiação em ecossistemas aquáticos e suas conseqüências na persistência de espécies, fluxo energético e ciclos biogeoquímicos.
Solar radiation is essential for life on Earth, providing energy for photosynthesis and heat. The total radiation that reaches the Earth surface, 9% is represented by the ultraviolet radiation (UV). Studies with cyanobacterial groups show negative effects of UV radiation on physiological processes such as growth, survival and enzymes of nitrogen metabolism and CO2 fixation. Cylindrospermopsis raciborskii is a filamentous nitrogen fixing cyanobacteria that has become one of the species of cyanobacteria of interest to researchers because of its potential toxicity and its high ecophysiological adaptability. In this work, we investigated the effect of UV-A, UV-B and UV (A + B) on the density, cell viability and occurrence of morphological changes by transmission electron microscopy. Natural intensities were used on strain of C. racirborskii in a period of 6 hours of treatment. The treatments UV-A and UV had significant negative effects on the density and integrity of membrane (99.3 and 95% of dead cells, respectively), while UV-B showed no significant difference in density, but induced alteration of membrane integrity in 57% of the cells at the end of treatment. Ultrastructural analysis showed morphological changes in all treatments characterized mainly by reducing the proportion of thylakoid structures and pigments accessories storage. Our results demonstrate the induction of cell death in strains of C. racirborskii treatments by UV-A and UV. However, the UV-B treatment seems to be less lethal to this strain in the intensity used. The understanding of processes of cell death in phytoplanktoic populations induced by UV radiation opens new perspectives on the influence of such radiation on aquatic ecosystems and its consequences on the persistence of species, energy flow and biogeochemical cycles.

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Lopes, Ismael Keslley Carloto. "IdentificaÃÃo de cianobactÃrias produtoras de saxitoxinas em reservatÃrio de usos mÃltiplos no semiÃrio cearense". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10883.

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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
No semi-Ãrido brasileiro, devido Ãs caracterÃsticas climÃticas, ao regime irregular de chuvas e Ãs caracterÃsticas do solo, a principal fonte de Ãgua para abastecimento humano tem sido os reservatÃrios artificiais de superfÃcie, aÃudes. A ocupaÃÃo e exploraÃÃo desordenada dos recursos naturais nas bacias hidrogrÃficas, alÃm da alta evaporaÃÃo e da radiaÃÃo solar, interferem negativamente na qualidade da Ãgua armazenada. Como consequÃncia, esses reservatÃrios apresentam um processo de eutrofizaÃÃo acelerado, levando frequentemente a floraÃÃes de fitoplÃnctons, comunidade esta predominantemente dominada por CianobactÃrias. Devido grande parte desses organismos serem produtores de toxinas, podendo causar uma sÃrie de problemas Ã populaÃÃo, decidiu-se monitorar a comunidade fitoplanctÃnica do aÃude SÃtios Novos, reservatÃrio de usos mÃltiplos, localizado no municÃpio de Caucaia-CE, de janeiro de 2010 a junho de 2011 investigando a produÃÃo de toxinas pelos organismos dominantes. Identificou-se 41 tÃxons, 19 de cianobactÃrias e 22 de algas. Apesar da predominÃncia de nÃmero de tÃxons de algas, estas representaram menos de 10% dos organismos quantificados, com exceÃÃo de 1 amostragem. JÃ as cianobactÃrias estiveram presentes em todas as amostragens, dominando quantitativamente o ambiente aquÃtico. Dentre o grupo de cianobactÃrias, destacaram-se Planktothrix agardhii (PA) e Cylindrospermosis raciborskii (CR). A abundÃncia de PA ao longo de todo o perÃodo de amostragem variou de 0 a 5.83x105 cel.mL-1, o que representou 94% da abundÃncia total do fitoplÃncton. A densidade mÃdia da PA foi 7.54.104 cel.mL-1. A abundÃncia CR no mesmo perÃodo variou de 0 a 3.32x104 cell.mL-1, representando 18,9% do total da comunidade fitoplanctÃnica. A abundÃncia mÃdia de CR foi 8.21.103 cel.mL-1. As espÃcies dominantes foram isoladas, e realizando-se bioensaios em camundongos, teste ELISA e mÃtodo de detecÃÃo por HPLC, observou-se a produÃÃo de STX e dc-STX pela CR e dc-GTX pela PA. Essa problemÃtica evidencia a necessidade da implementaÃÃo de aÃÃes integradas dos ÃrgÃos ambiental, de gestÃo dos recursos hÃdricos e companhia de sanamento estadual visando a prevenÃÃo e remediaÃÃo do processo de degradaÃÃo da qualidade da Ãgua, atuando na ampliaÃÃo do saneamento bÃsico, na educaÃÃo ambiental, na fiscalizaÃÃo dos usos e ocupaÃÃes do solo na bacia hidrogrÃfica mas, principalmente, no controle das atividades de piscicultura na bacia hidrÃulica, que ocorrem de maneira superintensiva.
In Brazilian semi-arid Northeast region due to irregular rainfall regime, climatic and soil characteristics, the main source of human water supply has been artificial surface reservoirs. Disorderly occupation and exploitation of natural resources on those hydrographic basins, alongside high evaporation and solar radiation, promote negative impact on stored water quality. As a consequence, the reservoirs present themselves in a process of accelerated eutrophication, often leading to phytoplankton blooms, predominantly dominated by Cyanobacteria. Due to many of these organisms are toxin-producing, which can cause a sort of problems to the population, it was decided to monitor the phytoplankton community of a multipurpose reservoir, located in the municipality of Caucaia-CE, from January 2010 to June 2011, as well as investigate the production of toxins by the dominant organisms. We identified 41 taxa, 19 of cyanobacteria and 22 of algae. Despite the predominance of algae over the identified taxa, they accounted for less than 10% of the quantified organisms, except for one sample. However cyanobacteria were present in all samples, quantitatively dominating the aquatic environment. Among the group of cyanobacteria, excelled Planktothrix agardhii (PA) and Cylindrospermosis raciborskii (CR). PA abundance along all sampling period ranged from 0 to 5.83x105 cells.mL-1 , which accounted for 94% of the total phytoplankton abundance. The average density of PA was 7.54.104 cells.mL-1 . The CR abundance in the same period ranged from 0 to 3.32x104 cells.mL-1 , accounting for 18,9% of total phytoplankton community. The average abundance of CR was 8.21.103 cells.mL-1. The dominant species were isolated and carrying out mice bioassay , ELISA and HPLC analysis, we observed the production of STX and dc-STX by CR and dc-GTX by PA. This issue highlights the need for the implementation of integrated actions from environmental agencies, water resources management and sanitation State companies towards the prevention and remediation of the degradation of water quality, acting in the expansion of sanitation, environmental education, oversighting of the use and occupation of the watershed lands, but mainly in the control of aquaculture activities in the hydraulic basin, which occur in a super intensive way.

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Moore, David. "Studies on the life cycle of the cyanobacterium Cylindrospermopsis raciborskii, focusing on akinete differentiation and germination /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18987.pdf.

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Paiva, Rafael Rodrigues de. "Efeitos da cianobactéria tóxica Cylindrospermopsis raciborskii na alimentação, sobrevivência e reprodução de um copépodo calanóide neotropical". Universidade Federal de Juiz de Fora, 2014. https://repositorio.ufjf.br/jspui/handle/ufjf/709.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Florações de cianobactérias podem causar efeitos negativos na qualidade da água e em comunidades biológicas. Dentre estas comunidades, copépodos calanóides possuem uma grande importância, sendo o grupo planctônico dominante em muitos ambientes de água doce. Apesar da importância destes copépodos para a dinâmica planctônica nestes sistemas, estudos sobre a interação entre estes animais e cianobactérias são ainda escassos. No presente estudo, os efeitos da cianobactéria invasiva e tóxica Cylindrospermopsis raciborskii (Woloszyńska) Seenayya et Subba Raju (1972) no copépodo calanóide tropical Notodiaptomus iheringi (Wright 1935) foram avaliados. Alimentação (taxas de remoção e seleção alimentar), sobrevivência (curvas de Kaplan-Meier, probabilidades de sobrevivência e Hazard ratio) e reprodução (% fêmeas com ovos e produção de ovos) deste copépodo foram estudadas usando dietas monoespecíficas e mistas de C. raciborskii e algas nutritivas (Chlamydomonas chlorastera ou Cryptomonas obovata). O aumento na proporção de C. raciborskii (> 50%) esteve relacionado a baixas taxas de alimentação, embora nenhuma diferença entre as taxas de remoção na cianobactéria e na alga nutritiva dentro de cada tratamento tenha sido encontrada. Efeitos negativos (25 ou 75% de C. raciborskii) ou neutros (50% de C. raciborskiii) na sobrevivência foram detectados nos tratamentos. Por outro lado, a reprodução em N. iheringi foi afetada pela presença de C. raciborskii, independente da proporção desta cianobactéria. Características da espécie C. raciborskii tais como toxicidade (e.g. saxitoxinas) e baixos valores nutricionais (e.g. ausência de PUFA) juntamente com não aclimatação prévia em N. iheringi à C. raciborskii podem explicar os diferentes resultados encontrados. Em geral, copépodos N. iheringi podem se alimentar e sobreviver em dietas com C. raciborskii. Porém, dietas de C. raciborskii não suportam a reprodução destes animais. Este é o primeiro estudo que avalia o efeito de C. raciborskii na sobrevivência e reprodução de copépodos calanóides. Os resultados deste trabalho podem contribuir para o entendimento do comportamento alimentar assim como a dinâmica populacional de copépodos calanóides na presença da cianobactéria C. raciborskii.
Cyanobacterial blooms can cause negative impacts on water quality and biological communities. Among these biological communities, calanoid copepods have a great importance, being the dominant planktonic group in many freshwater systems. Despite the importance of calanoid copepods to plankton dynamics in freshwater systems, studies on the interaction between these animals and cyanobacteria are still scarce. Here the effects of the invasive and toxic cyanobacterium Cylindrospermopsis raciborskii (Woloszyńska) Seenayya et Subba Raju (1972) on the tropical calanoid copepod Notodiaptomus iheringi (Wright 1935) were evaluated. Feeding (clearance rates and selective feeding), survival (Kaplan-Meier curves, survival probabilities and hazard ratios) and reproduction (% females with eggs and egg production) of this copepod were studied using single and mixed diets of C. raciborskii and nutritious algae (Chlamydomonas chlorastera or Cryptomonas obovata). The increase on C. raciborskii proportion (> 50%) was related to lower feeding rates although no differences between the clearance rates on the cyanobacterium and nutritious algae within each treatment were found. Negative (25 or 75% of C. raciborskii) or neutral (50% of C. raciborskiii) effects on survival were detected throughout the treatments. On the other hand, the reproduction in N. iheringi was strongly affected by the presence of C. raciborskii, independently of the proportion of this cyanobacterium. Features of the species C. raciborskii such as toxicity (e.g. saxitoxins) and low nutritional values (e.g. absence of PUFA) along with non-previous acclimation in N. iheringi to C. raciborskii might explain the different outcomes found in the present study. Overall, N. iheringi copepods can feed and survive in diets with C. raciborskii. However, C. raciborskii diets cannot support reproduction of these animals. This is the first study that evaluates the effects of C. raciborskii on survival and reproduction of calanoid copepods. The outcomes found in this work might contribute to the understanding of the feeding interactions as well as the population dynamics of calanoid copepods in the presence of the cyanobacterium C. raciborskii.

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Ferreira, Raphaela Moreira. "Efeitos da limitação de fósforo na eficiência fotossintética, na morfologia e no crescimento de Cylindrospermopsis raciborskii". Universidade Federal de Juiz de Fora (UFJF), 2007. https://repositorio.ufjf.br/jspui/handle/ufjf/4664.

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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
Cylindrospermopsis raciborskii é uma cianobactéria filamentosa fixadora de nitrogênio que tem se tornado alvo de diversos estudos devido a sua toxicidade potencial e sua elevada adaptabilidade ecofisiológica. Seu sucesso adaptativo é atribuído, dentre outras coisas, a sua tolerância à baixa disponibilidade de luz e sua elevada afinidade por fósforo, além da capacidade de estocar esse nutriente. Devido a recente ocorrência de florações de C. raciborskii em todo o mundo, faz-se necessário estudar a ecologia e fisiologia dessa espécie visando o controle das florações. O presente trabalho buscou avaliar os efeitos da limitação de fósforo nas taxas de produtividade e eficiência fotossintética, na morfologia e no crescimento de populações tóxicas e não tóxicas de C. raciborskii. As cepas utilizadas apresentaram baixa eficiência fotossintética, sendo esta ainda menor após período de limitação de fósforo, o que foi atribuído ao baixo conteúdo de clorofila a. No entanto, a produtividade específica foi elevada, mesmo após a limitação por fósforo. Tal fato é certamente essencial para o desencadeamento de florações. A limitação de fósforo imposta as cepas provocou diminuição na relação superfície:volume das células, crescimento lento, aparecimento de heterocitos e acinetos e aparecimento de filamentos com células de diferentes tamanhos evidenciando a importância desse nutriente na determinação da morfologia de C. raciborskii. As alterações morfológicas relacionadas à diminuição do tamanho celular também estão relacionadas à baixa eficiência fotossintética devida a alterações na arquitetura celular. Os resultados encontrados sugerem cautela na identificação exclusivamente morfológica da espécie bem como demonstram que a interrupção do aporte de fósforo em ecossistemas aquáticos sujeitos a florações de C. raciborskii, enquanto medida isolada, não é suficiente para prevenir a ocorrência desses eventos.
Cylindrospermopsis raciborskii is a filamentous cyanobacteria able to fix N2 and has been object of many studies because of its potential toxicity and wide ecophysiologic adaptability. Its success is ascribed to, among other things, its shade adaptability, high affinity for phosphorus besides being able to store this nutrient. Since there has been many recent blooms of C. raciborskii around the world it become indispensable to know the ecology and physiology of these species. These work intent to evaluate the effects of phosphorus limitation on photosynthetic efficiency, morphology and growth of C. raciborskii. The species showed a low photosynthetic efficiency (α) under natural conditions and an even lower α after P limitation, which were attributed to its low chlorophyll a content. However, C. raciborskii had a high photosynthetic capacity (Pmb), before and after P limitation period. These ability is essential for the development of blooms. P limitation also reduced the growth and induced extreme morphological changes, such as: low surface:volume ratio, formation of akinetes, trichomes with different cell sizes proving the relevance of these nutrient on morphology of the species. These morphological changes had also influenced the low α found in these work. Our results suggest prudence on the taxonomic identification of C. raciborskii based on morphological characteristics and they demonstrate that the discontinuity on P load to aquatic ecosystems subject to C. raciborskii blooms does not assure that the blooms will not happen.

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VILAR, Mauro Cesar Palmeira. "Efeito do balanço pH/carbono inorgânico em parâmetros ecofisiológicos de Cylindrospermopsis raciborskii (Cyanobacteria) sob condições experimentais". Universidade Federal Rural de Pernambuco, 2015. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5239.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Cylindrospermopsis raciborskii (Wolozynska) Seenayya & Subba Raju is a cosmopolitan diazotrophic and potentially toxic specie considered as invasive in different latitudes. Its capacity of occupying several niches is a feature which is linked to its physiological traits, which allow it to have wide ecological amplitude to several environmental parameters. However, in laboratory conditions that specie might show some growth limitations related to pH, temperature and nutrients. In this scenario, this work aimed to investigate the effect of pH and source of inorganic carbon in growth-related parameters of C. raciborskii. The strain ITEP-A1 (saxitoxin-producing) was cultured in ASM-1 medium and maintained under controlled conditions. Experiments were worked out in 2L erlenmeyers filled with 1.5 L culture medium in different pH ranges and inorganic carbon availability, with/without CO2 enriched-air bubbling. Cyanobacterial growth, morphological traces, biomass acquisition, temperature, pH, conductivity, alkalinity and total inorganic carbon dissolved were analyzed. Results were compared using repeated-measures ANOVA and ANOVA one way with Tukey’s test post hoc (p<0.05). Graphics and statistical analysis were performed in Statistica 7.0 and R i386 3.1.2, respectively. C. raciborskii ITEP-A1 showed better growth rate and biomass under alkaline pH (> 8.0) (P<0,05) in both aeration conditions. pH, alkalinity and inorganic carbon showed an increasing trend throughout the experiment under pH free. At the pH condition > 8.0 with aeration the bicarbonate ion (HCO3-) was the main source of inorganic carbon available to the photosynthetic process, which favored C. raciborskii growth. These results can be extrapolated to a global scale, and suggested as factors that have favored the distribution and expansion of this cyanobacterium to other latitudes.
Cylindrospermopsis raciborskii (Wolozynska) Seenayya & Subba Raju é uma espécie diazotrófica cosmopolita, potencialmente tóxica e considerada invasora em diferentes latitudes. A capacidade de ocupar diferentes nichos é uma característica que está ligada às suas peculiaridades fisiológicas, as quais permitem que possua uma elevada amplitude ecológica para diferentes variáveis ambientais. No entanto, em condições de cultivo, essa espécie pode apresentar limitações para o crescimento relacionadas ao pH, temperatura e nutrientes. Neste cenário, o presente trabalho objetivou investigar o efeito do pH e fonte de carbono inorgânico em parâmetros relacionados ao crescimento de C. raciborskii. A cepa ITEP-A1 (produtora de saxitoxinas) foi cultivada em meio de cultura ASM-1 e mantida sob condições controladas. O delineamento experimental consistiu do cultivo da linhagem ITEP-A1 em diferentes faixas de pH e disponibilidade de carbono inorgânico, com e sem aeração. Os experimentos foram realizados em erlenmeyers de 2 L com 1,5 L de meio de cultura e foram analisadas curvas e taxas de crescimento, traços morfológicos, aquisição de biomassa, temperatura, pH, condutividade, alcalinidade e carbono inorgânico total dissolvido. Os resultados foram comparados usando ANOVA fatorial com medidas repetidas e ANOVA unifatorial com Teste de Tukey a posteriori, sendo as análises estatísticas e gráficos realizados no programa Statistica 7.0 e R i386 3.1.2, respectivamente. C. raciborskii ITEP-A1 apresentou melhor taxa de crescimento e biomassa sob pH alcalino (>8,0), em ambas condições de aeração. Na condição de pH > 8,0 e com aeração, o íon bicarbonato (HCO3-) foi a principal fonte de carbono inorgânico disponível ao processo fotossintético, o que favoreceu o crescimento de C. raciborskii. Tais resultados podem ser extrapolados para uma escala global, e sugeridos como fatores que têm favorecido a distribuição, bem como expansão dessa cianobactéria para outras latitudes.

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BRITO, Maiara Tábatha da Silva. "Influência do pH e carbono inorgânico na competição entre as cianobactérias Cylindrospermopsis raciborskii e Microcystis aeruginosa". Universidade Federal Rural de Pernambuco, 2017. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/7566.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Cyanobacterial bloom in freshwater are mainly associated with the nutritional enrichment of the water, but currently, high concentration of atmospheric carbon dioxide (CO2) is also favoring its dominance. During bloom, the consumption of free CO2 and nutrients increases the pH of the water. Thus, when it diffuses in water, atmospheric CO2 becomes available as bicarbonate (HCO3-) and carbonate (CO32-), promoting changes in the phytoplankton community due to the competitive advantage that some species present in use of HCO3-. Cylindrospermopsis raciborskii and Microcystis aeruginosa are cyanobacteria widely distributed in freshwater aquatic ecosystems, bloom forming and known to make use of HCO3-. This study was carried out in order to investigate the competitive relationship between these species due to changes in pH and availability of inorganic carbon. Were performed cultures with and without aeration, with and without bicarbonate and in three different pH conditions (free, 6.8 and 8.2) with the strains ITEP-A1 of C. raciborskii and NPLJ4 of M. aeruginosa. Cultures started with the same biovolume and had their exponential growth phase extended from reinoculation into new culture medium (returning to the initial biovolume). For the mixed cultures the species with the lowest growth was considered. The growth rates (μ.day -1) and species yield, pH, alkalinity and inorganic carbon of the cultures were evaluated by repeated measures ANOVA. Isolate M. aeruginosa presented higher growth rates at pH 8.2 and free, and reduced growth at pH 6.8 while C. raciborskii was not influenced by pH. Both species promoted significant changes in pH in the non-buffered cultures (free pH). Aeration and bicarbonate were determinant factors for the response of the species in the competition cultures. In non-buffered cultures, with aeration and without addition of bicarbonate C. raciborskii was better competitor than M. aeruginosa, whereas this was best competitor in the cultures without aeration and with addition of bicarbonate. It was possible to observe changes in the competitive responses of the species to changes in pH and alkalinity and, consequently, to the proportions of dissolved inorganic carbon. Thus, with increased eutrophication of aquatic ecosystems associated with increased alkalinity and pH, changes in the competitive relationships of species are likely to occur, since the relief of inorganic carbon limitation may favor the dominance of potentially toxic cyanobacteria such as those of the genus Microcystis.
Florações de cianobactérias em ambientes límnicos são associadas principalmente ao enriquecimento nutricional dos mananciais porém, atualmente, altas concentração de dióxido de carbono (CO2) atmosférico também vem favorecendo sua dominância. Durante a floração, o consumo de CO2 livre e de nutrientes elevam o pH das águas. Assim, ao se difundir na água o CO2 atmosférico torna-se disponível como bicarbonato (HCO3-) e/ou carbonato (CO32-), promovendo mudanças na comunidade fitoplanctônica devido a vantagem competitiva que algumas espécies apresentam no uso do HCO3-. Cylindrospermopsis raciborskii e Microcystis aeruginosa são cianobactérias amplamente distribuídas nos ecossistemas aquáticos dulciaquícolas, formadoras de florações e conhecidas por fazer uso do HCO3-. Este estudo foi realizado a fim de investigar a relação competitiva entre estas espécies diante de mudanças no pH e disponibilidade de carbono inorgânico. Foram realizados cultivos com e sem aeração, com e sem adição de bicarbonato e em três diferentes condições de pH (livre, 6,8 e 8,2) com as cepas ITEP-A1 de C. raciborskii e NPLJ-4 de M. aeruginosa. Os cultivos iniciaram-se com o mesmo biovolume e tiveram a sua fase de crescimento exponencial estendida a partir de reinoculação em novo meio de cultura (retornando ao biovolume inicial). Para os cultivos mistos considerou-se a espécie com o menor crescimento. As taxas de crescimento (μ.dia -1) e rendimento das espécies, o pH, alcalinidade e carbono inorgânico dos cultivos foram avaliados por ANOVA Fatorial de medidas repetidas. Isoladamente, M. aeruginosa apresentou maiores taxas de crescimento em pH 8,2 e livre, e crescimento reduzido em pH 6,8, enquanto C. raciborskii não foi influenciada pelo pH. Ambas as espécies promoveram mudanças significativas no pH nos cultivos não tamponados (pH livre). A aeração e o bicarbonato foram fatores determinantes para a resposta das espécies nos cultivos em competição. Nos cultivos não tamponados, com aeração e sem adição de bicarbonato C. raciborskii foi melhor competidora que M. aeruginosa, enquanto que esta foi melhor competidora nos cultivos sem aeração e com adição de bicarbonato. Foi possível constatar mudanças nas respostas competitivas das espécies diante de alterações no pH e alcalinidade e, consequentemente, das proporções de carbono inorgânico dissolvido. Assim, com o aumento da eutrofização dos ecossistemas aquáticos associado a um aumento da alcalinidade e pH, mudanças nas relações competitivas das espécies estão propensas a ocorrer, visto que o alivio da limitação por carbono inorgânico pode favorecer a dominância de cianobactérias potencialmente tóxicas como as do gênero Microcystis.

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JÃnior, Francisco Rodrigues PessÃa dos Santos. "Study of community phytoplankton Acarape do Meio reservoir with emphasis on cyanobacteria". Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11675.

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The water quality from a reservoir is subject to all natural and anthropogenic factors acting in its watershed . The state of CearÃ since the late 80s has adopted a policy of construction of water reservation to fulfill the so-called hydric emptiness. It has been observed that the waters of these new lakes, as well as the previously constructed , is experiencing a process of deterioration, mainly caused by eutrophication. The eutrophication causes a series of changes in the water system, the most relevant being the cyanobacteria blooms. Some of these organisms may be capable of producing toxins, termed cianotoxins , which are able of causing diseases and, in extreme cases, humans and animals death. This work was performed at the Acarape do Meio reservoir, located in the municipality of RedenÃÃo - CearÃ. Phytoplankton community data, with emphasis on cyanobacteria, was analyzed during the period of May 2012 to May 2013. 49 taxa distributed into 07 classes , Cyanobacteria representing 40 %, were identified. Despite the elevated number of taxa of algae, total quantity of these organisms ranged from 2.16 % (May/2012 ) to 0.34 % ( June/2012 ) while cyanobacteria were present in all samples, ranging between 97.84 % ( May/12 ) to 99.66% ( junho/12 ), quantitatively dominating the aquatic environment . The dominant species in all samples was the cyanobacterium Cylindrospermosis raciborskii, reaching an average density in April, 2012 of 1.121.328 cel.mL-1. As for the Trophic State Index, it pointed out that the reservoir was eutrophic . When the density of cyanobacteria was correlated with rainy periods and macronutrients , it showed a strong positive correlation with seasonality but a weak correlation with nitrogen and phosphorus, probably caused by the high quantities of these macronutrients present during the study period.
A qualidade da Ãgua de um reservatÃrio estÃ condicionada a todos os fatores naturais e antrÃpicos que agem na sua bacia hidrogrÃfica. O estado do CearÃ desde o final da dÃcada de 80 adotou uma polÃtica de construÃÃo de obras de reservaÃÃo hÃdrica, voltadas a preencher os chamados vazios hÃdricos. O que se tem observado, Ã que as Ãguas destes aÃudes, bem como os anteriormente construÃdos, vem sofrendo um processo de deterioraÃÃo de suas Ãguas, ocasionado principalmente pelo processo de eutrofizaÃÃo, onde as aÃÃes antrÃpicas sÃo as causas principais. A eutrofizaÃÃo ocasiona uma sÃrie de mudanÃas na massa de Ãgua de um sistema hÃdrico, sendo a mais relevante o surgimento de floraÃÃo de cianobactÃrias, podendo alguns destes organismos, serem capazes de produzir toxinas, denominadas de cianotoxinas, as quais sÃo capazes de ocasionar doenÃas e, em casos extremos, o Ãbito de seres humanos e animais. Este trabalho foi realizado no aÃude Acarape do Meio, localizado no municÃpio de RedenÃÃo-CE, com o objetivo de analisar durante o perÃodo de Maio de 2012 a Maio de 2013, a comunidade fitoplanctÃnica do citado reservatÃrio com Ãnfase em cianobactÃrias. Foram identificados 49 tÃxons distribuÃdos em 07 classes, dentre as CianobactÃrias representaram 40 %. Apesar da existÃncia do bom nÃmero de tÃxons de algas, estas variaram entre 2,16% (maio/2012) e 0,34% (junho/2012) dos organismos quantificados no reservatÃrio, enquanto as cianobactÃrias estiveram presentes em todas as amostragens, variando entre 97,84% (maio/12) a 99,66% (junho/12), dominando quantitativamente o ambiente aquÃtico. A espÃcie dominante em todas as amostragens foi a cianobactÃria Cylindrospermosis raciborskii, chegando a atingir uma densidade mÃdia no mÃs de abril de 1.121.328 cÃl. mL-Â. Quanto ao IET, este apontou que o manancial estava hipereutrÃfizado. Quando a densidade de cianobactÃrias foi correlacionada aos perÃodos chuvosos e secos e aos macronutrientes (nitrogÃnio e fÃsforo), havendo uma correlaÃÃo positiva com a sazonalidade, e uma fraca correlaÃÃo com o nitrogÃnio e o fÃsforo, provavelmente, ocasionada pela a alta taxa destes macronutrientes presentes durante o perÃodo de estudo.

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Bressan, Fernanda Affonseca. "Fatores reguladores da dominância de Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba-Raju no Reservatório Tabocas, Caruaru, PE". Universidade Federal do Rio de Janeiro, 2001. http://hdl.handle.net/11422/3500.

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CAPES
Em 1996, a mortalidade maciça de pacientes durante tratamento de hemodiálise com água proveniente do Reservatório Tabocas, Caruaru - PE, foi atribuída à ação de cianotoxinas. Após o evento, um detalhado programa de monitoramento limnológico e ecotoxicológico foi implantado, incluindo estudos ecológicos do fitoplâncton. Considerando que cianofíceas são as algas dominantes no Reservatório Tabocas e a relevância que assumem para a saúde pública, o presente estudo teve como objetivo reconhecer os padrões espaciais e temporais de populações de cianofíceas, especialmente Cylindrospermopsis raciborskii (Woloszynska) Seenayya & SubbaRaju, bem como investigar os fatores que regulam sua dominância. Fitoplâncton e variáveis abióticas da água foram analisados a partir de amostras sub-superficiais, coletadas quinzenalmente em três estações do reservatório, no período de novembro de 1997 a outubro de 1998. Um perfil vertical foi amostrado somente na estação junto à barragem. Com base na composição e biomassa do fitoplâncton, foram reconhecidos três períodos: período I, com biomassas menores e dominância de C. raciborskii; período II, com biomassas semelhantes ao período I, mas co-dominância de C. raciborskii e Cyanodictyon imperfectum Cronberg & Weibull; período III - de biomassas mais elevadas e dominância de C. raciborskii. Biomassa total relacionou-se inversamente ao nível do reservatório e à luz. Nossos dados suportam que dominância de C. raciborskii foi favorecida por altas temperaturas, elevado pH, baixas intensidades luminosas e teores de fósforo relativamente baixos. A constância ambiental definida pela seca do semi-árido de Pernambuco foi fator decisivo para a prolongada dominância de cianofíceas no Reservatório Tabocas. De acordo com a abordagem fitossociológica originalmente desenvolvida para a vegetação terrestre e recentemente aplicada ao fitoplâncton, grupos de espécies podem ser eficientes descritores do meio onde vivem. As associações de algas mais representativas no Reservatório Tabocas foram S e Sn, ambas marcadas por sua habilidade para se desenvolverem em baixos teores de fósforo e em baixas intensidades luminosas.
ln 1996, during haemodialysis procedure using water from Tabocas reservoir in Caruaru, Pernambuco, a massive human intoxication associated with cyanotoxins was registered. After that, a detailed monitoring program was established, including phytoplankton ecology studies. Since cyanophytes were the dominant algal group and considering their potential relevance to public health, the goals of this study were to recognise temporal and spatial patterns of distribution of these populations, mainly Cylindrospermopsis raciborskii (Woloszynska) Seenaya & Subba-Raju , and to understand the main regulating factors of its dominance. Phytoplankton and abiotic variables of water were sampled during November 1997 to October 1998, at subsurface, biweekly in three sampling stations. A vertical profile was analysed only in the station near to the dam. Considering phytoplankton composition and biomass, three periods were recognised: period I, with lower biomass and C. raciborskii dominance; period II, with similar biomass to period 1, but co-dominance of C. raciborskii and Cyanodictyon imperfectum Cronberg & Weibull; period III, with the highest biomass and dominance of C. raciborskii. Total biomass was inversely related to reservoir level and to the light. Our data support that C. raciborskii dominance was favoured by high temperature, high pH, low light and low inorganic dissolved phosphorus concentrations. Environmental constancy, defined by the persistent and strong drought, was a decisive factor to promote the long-standing cyanophytes dominance in Tabocas reservoir. According to the phytossociological approach originally developed to terrestrial vegetation and recently applied to phytoplankton, groups of species can be efficient descriptors of the environment where they live. The most representative algal assemblages in Tabocas Resevoir was S and Sn, both fitted to growth in low phosphorus concentrations and low light.

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43

Risseti, Caroline Hoff. "Moléculas bioativas e filogenia de isolados brasileiros de cianobactérias dos gêneros Dolichospermum, Sphaerospermopsis, Cuspidothrix, Cylindrospermopsis e Microcystis". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-18012013-142454/.

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O número crescente de descobertas de substâncias bioativas produzidas pelo metabolismo secundário de cianobactérias tem despertado o interesse de grupos de pesquisa no mundo todo com o objetivo comum de descrever e explorar estas moléculas e entender a sua biossíntese. No Brasil, as pesquisas sobre moléculas bioativas produzidas por linhagens de cianobactérias nativas são escassas. Neste trabalho, utilizando iniciadores específicos da PCR e sequenciamento, a presença de genes envolvidos na biossíntese da neurotoxina saxitoxina (STX) foi confirmada em representantes dos gêneros Dolichospermum, Sphaerospermopsis, Cuspidothrix e Cylindrospermopsis, enquanto que genes da citotoxina cilindrospermopsina (CYN) foram detectados somente em representantes de Cylindrospermopsis. Genes envolvidos com a produção dos inibidores enzimáticos, microviridina (MDN) e a cianobactina microciclamida (MCA) foram sequenciados em isolados do gênero Microcystis. Os genomas das linhagens de Cylindrospermopsis raciborskii CENA302 e CENA303 foram sequenciados usando a plataforma HiScan SQ (Ilumina) com biblioteca pareada 2 x 100 pb. O genoma da Sphaerospermopsis torques-reginae ITEP-024 foi sequenciado utilizando a plataforma Ion Torrent (Life Technologies) com tamanhos de fragmentos de até 200 pb. As tentativas de montagem ab initio dos genomas foram realizadas e o agrupamento gênico da saxitoxina (28 kb) da linhagem C. raciborskii CENA302 foi identificado e caracterizado. As análises filogenéticas das sequências de aminoácidos envolvidos com a biossíntese das moléculas bioativas avaliadas demonstraram que os isolados brasileiros de cianobactérias formam clados com elevado valor de reamostragem com sequências homólogas de cianobactérias conhecidas como produtoras dessas moléculas. Neste estudo é relatada pela primeira vez a presença de genes cyr em linhagens da América do Sul de C. raciborskii e a presença simultânea de genes cyr e sxt em uma única linhagem de C. raciborskii. Além disso, este é o primeiro estudo que relata a presença de genes envolvidos na biossíntese de MDN e MCA nas espécies de cianobactérias M. protocystis, M. panniformis e M. wesenbergii. Análises por espectrometria de massas acoplada a cromatografia líquida (LC-MS) e imunoensaio enzimático (ELISA) foram utilizadas a fim de detectar e identificar variantes estruturais das moléculas bioativas das cianobactérias que tiveram os genes biossintéticos sequenciados. A análise de LC-MS mostrou a produção das variantes GTX2, GTX3, STX e dc-STX pela linhagem C. raciborskii CENA302, enquanto que a linhagem C. raciborskii CENA305 apresentou as variantes NEO, C1 e dcGTX3. As quatro novas variantes de MCY, [D-Val1]MC-RR, [D-Leu/Ile1]MC-RR, [D-Leu/Ile1]MC-YR e [D-Phe1]MC-LR, foram encontradas nas espécies M. panniformis SPC702 e M. protocystis SPC697. Este é o primeiro relato da produção de MCY por essas duas espécies de Microcystis. Dezesseis linhagens que ainda não possuíam as sequências do gene de RNAr 16S foram sequenciadas. O resultado da análise filogenética das sequências do gene de RNAr 16S foi coerente com as descrições morfológicas, sendo que todas as linhagens foram caracterizadas em nível de espécie. As informações geradas neste estudo contribuem para o aumento do conhecimento da diversidade metabólica dos isolados brasileiros de cianobactérias e trazem nova visão sobre a evolução dessas moléculas produzidas pelo metabolismo secundário
The growing numbers of discoveries of bioactive substances produced by cyanobacterial secondary metabolism has attracted the interest of research groups around the world with the common goal of describing and exploring these molecules and understanding their biosynthesis. In Brazil, researches on bioactive molecules produced by native cyanobacterial strains are scarce. In this work, using specific PCR primers and sequencing, the presence of genes involved in the biosynthesis of the neurotoxin saxitoxin (STX) was confirmed in representatives of the genera Dolichospermum, Sphaerospermopsis, Cuspidothrix and Cylindrospermopsis, while genes of the cytotoxin cylindrospermopsin (CYN) were detected only in representatives of Cylindrospermopsis. Genes involved in the production of protease inhibitors, microviridin (MDN) and the cianobactin microciclamide (MCA), were sequenced in isolates of the genus Microcystis. The genomes of Cylindrospermopsis raciborskii strains CENA302 and CENA303 were sequenced using the high-throughput platform HiScan SQ (Illumina) as paired-ends 2 x 100 bp. The Sphaerospermopsis torques-reginae ITEP-024 genome was sequenced using the high-throughput platform Ion Torrent (Life Technologies) with fragment sizes up to 200 bp. Attempts of ab initio genomes assembly were performed and the 28 kb saxitoxin gene cluster of C. raciborskii strains CENA302 was identified and characterized. Phylogenetic analyses of amino acid sequences involved in the biosynthesis of the bioactive molecules evaluated showed that the Brazilian cyanobacterial isolates formed clades with high bootstrap values with homologous sequences of known cyanobacterial producers of these molecules. In this study is reported for the first time the presence of cyr genes in South America strains of C. raciborskii and the simultaneous presence of cyr and sxt genes in a single C. raciborskii strain. Furthermore, this is the first study reporting the presence of genes involved in the biosynthesis of MDN and MCA in the cyanobacterial species M. protocystis, M. panniformis e M. wesenbergii. Analyses by mass spectrometry coupled to liquid chromatography (LC-MS) and enzyme immunoassay (ELISA) were used to detect and identify structural variants of bioactive molecules of the cyanobacteria that had the biosynthetic genes sequenced. Analysis of LC-MS showed the production of the variants GTX2, GTX3, STX and dc-STX by the C. raciborskii strain CENA302, whereas the strain C. raciborskii CENA305 presented the variants NEO, C1 and dcGTX3. The new four MCY variants [D-Val1]MC-RR, [D-Leu/Ile1]MC-RR, [D-Leu/Ile1]MC-YR and [D-Phe1]MC-LR were found in the species M. panniformis SPC702 and M. protocystis SPC697. This is the first report of the MCY production by these two species of Microcystis. Sixteen strains that still lacked the 16S rRNA gene sequences were sequenced. The result of the phylogenetic analysis of 16S rRNA gene sequences was consistent with the morphological descriptions, and all strains were characterized to species level. The informations generated in this study contribute to the increase of knowledge on metabolic diversity of Brazilian cyanobacterial strains and bring new insight into the evolution of these molecules produced by secondary metabolism

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Santos, Paulo Vagner dos. "Interação entre Cylindrospermopsis raciborskii e Microcystis aeruginosa: implicações no crescimento de culturas e na produção de microcistinas". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-30072009-092010/.

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Cianobactérias desempenham importante papel ecológico em diversos ecossistemas terrestres e aquáticos. Contudo, tornam-se problema de saúde pública quando biossintetizam compostos secundários tóxicos, denominados cianotoxinas, as quais podem atuar sobre diversos organismos. Sistemas aquáticos impactados favorecem o desenvolvimento destes microrganismos, que podem tornar-se dominantes em função dos diversos mecanismos que lhes conferem vantagens adaptativas em relação aos demais grupos fitoplanctônicos. Muitas vezes, elas apresentam-se sob forma de florescimento, cuja toxicidade varia de acordo com espécies e cepas que o compõem. Apesar das cianobactérias Cylindrospermopsis raciborskii e Microcystis aeruginosa formarem florações, terem potencial tóxico, serem competitivas e estarem presentes em diversos reservatórios, é desconhecido o efeito da interação entre elas na produção de microcistina. Para esclarecer esta questão, nesta pesquisa, foi estudada a interação entre cepas de C. raciborskii e M. aeruginosa visando: caracterizar o cultivo das espécies em monocultura e cultura mista; verificar se o caráter tóxico das cepas favoreceu a competição; mensurar a microcistina de M. aeruginosa e avaliar o efeito da interação sobre esta variável. Em salas climatizadas de cultivo (22ºC, fotoperíodo 12h, 60 \'mü\'mol photon/\'M POT.2\'.s) experimentos de interação foram realizados em culturas batch compostas por três tratamentos: (1) monocultura de M. aeruginosa, (2) monocultura de C. raciborskii, (3) cultura mista de M. aeruginosa e C. raciborskii. Foram realizadas análises da densidade e biovolume dos organismos, da velocidade específica de crescimento (\'mü\') e tempo de duplicação (Td) e da concentração de microcistinas, clorofila-a e nutrientes. A interação reduziu em até 22% a \'mü\' das linhagens estudadas. Tanto C. raciborskii quanto M. aeruginosa apresentaram vantagem competitiva em pelo menos um dos ensaios e, no caso de linhagem tóxica de M. aeruginosa, verificou-se que o seu caráter tóxico favoreceu a competição da espécie com linhagem atóxica de C. raciborskii. Além disso, M. aeruginosa elevou em até 53% a síntese de microcistina ao interagir com C. raciborskii. Este processo poderia se relacionar a três principais mecanismos: competição por interferência, produção de alelopáticos e comunicação química. Estudos de balanços genéticos dos florescimentos bem como da possível comunicação química existente entre cianobactérias são ferramentas investigativas importantes que poderão ajudar no aprimoramento da prevenção e manejo de florações tóxicas.
Cyanobacteria play important ecological role in many terrestrial and aquatic ecosystems. However, they become a public health problem when synthesize secondary toxic compounds, known as cyanotoxins, which may act on several organisms. Impacted aquatic systems favor their growth and these microorganisms can become dominant due to mechanisms that confer them adaptive advantages in relation to other phytoplanktonic groups. Frequently, cyanobacteria can form water blooms, whose toxicity varies according to their species and strains composition. Although the cyanobacteria Cylindrospermopsis raciborskii and Microcystis aeruginosa can form blooms, have toxic potential, are competitive and present in several reservoirs, it is unknown the interaction effect between them in the production of microcystins. To solve this question, the interaction among strains of C. raciborskii and M. aeruginosa was studied to: characterize the culture of the species in monoculture and mixed culture; check whether the character of toxic strains favored the competition; measure microcystin concentration produced by M. aeruginosa and evaluate interaction effect on this variable. In climatized growth room (22°C, 12h photoperiod, 60 \'mü\'mol photon/\'M POT.2\'.s) four interaction experiments composed by three treatments were performed in batch cultures: (1) monoculture of M. aeruginosa, (2) monoculture of C. raciborskii, (3) mixed culture of M. aeruginosa and C. raciborskii. Density and biovolume, specific growth rate (\'mü\'), doubling time (Td) and concentration of microcystin, chlorophyll-a and nutrients analyses were performed. The interaction reduced up to 22% the of studied strains. Both C. raciborskii and M. aeruginosa presented competitive advantage in at least one of the tests. In the case of toxic strain of M. aeruginosa, it was found that its toxic character favored the competition with non-toxic strain of C. raciborskii. Furthermore, M. aeruginosa increased by 53% the synthesis of microcystin while interacting with C. raciborskii. This process could be related to three main mechanisms: interference competition, communication and production of allelopathic chemicals. Genetical balance studies of blooms as the possible chemical communication existing among cyanobacteria are important investigative tools that might help prevention and management improvement of toxic blooms.

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Schaker, Patricia Dayane Carvalho. "Análise genômica de isolados brasileiros de Cylindrospermopsis raciborskii com enfoque em cilindrospermopsina e fixação biológica de N2". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-26032013-164819/.

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A espécie de cianobactéria Cylindrospermopsis raciborskii pertence a ordem Nostocales e tem a capacidade de realizar a fixação biológica do N2 atmosférico, sintetizar cianotoxinas e também de proliferar em águas doces formando florações de cianobactérias nocivas. A população de C. raciborskii encontrada no Brasil é conhecida por produzir derivados de saxitoxina (STX), enquanto cilindrospermopsinas (CYN), as quais são detectadas em isolados de outros países, não têm sido detectada em isolados brasileiros. Neste estudo, a produção de CYN por dois isolados brasileiros de C. raciborskii, CENA302 e CENA303, submetidos a diferentes condições nutricionais, foi avaliada usando o teste imunológico ELISA específico para detecção de CYN. Em seguida, genes evolvidos na biossíntese de CYN foram buscados no genoma dessas duas linhagens usando amplificações por PCR com iniciadores específicos e posterior sequenciamento Sanger, bem como sequenciamento genômico na plataforma HiScan SQ. Além disso, foram realizadas buscas nos dois genomas obtidos pela plataforma HiScan SQ de genes envolvidos com a síntese de algumas outras moléculas já descritas em cianobactérias, bem como aqueles relacionados com a fixação biológica de N2 e diferenciação do heterócito. Apesar da utilização de diferentes condições nutricionais, não foi detectada a produção de CYN no ensaio de ELISA em ambos os isolados de cianobactérias. No sequenciamento Sanger, dos nove genes sintetases de CYN buscados, quatro foram amplificados e sequenciados na linhagem C. raciborskii CENA302 e três na linhagem CENA303. Estas sequências de nucletídeos foram traduzidas em aminoácidos, e as funções das proteínas e os domínios preditos confirmaram a sua identidade como genes sintetase de CYN. O sequenciamento dos genomas completos das duas linhagens apresentou altos valores de qualidade de bases e elevada cobertura genômica. A busca por genes sintetase de CYN nos dois genomas foi realizada pelo mapeamento por referência das leituras, mostrando que algumas porções do agrupamento estavam contempladas no genoma, representando aproximadamente 10% do agrupamento de CYN. A anotação das regiões entre os genes descritos como flanqueadores do agrupamento CYN mostrou uma inversão gênica indicando a ocorrência de eventos que podem ter levado a perda ou dispersão no genoma deste agrupamento. Os genes anotados relacionados com fixação biológica de N2 e diferenciação do heterócito nas linhagens CENA302 e CENA303 apresentaram altas identidades com genes homólogos descritos em C. raciborskii. A ausência de alguns nucleotídeos no gene hetP envolvido na formação do heterócito possivelmente levou a perda de sua função na C. raciborskii CENA303, impedindo a diferenciação das células vegetativas em heterócitos, uma vez que não foi observado a presença dessa célula diferenciada em nenhuma das condições nutricionais avaliadas. Todos os genes de moléculas bioativas conhecidas de cianobactérias buscados pelo mapeamento por referência das leituras não foram encontrados nos genomas das linhagens C. raciborskii CENA302 e CENA303. Os resultados obtidos neste estudo revelaram a possibilidade de estar ocorrendo eventos evolutivos que estão causando a perda dos genes responsáveis pela síntese de CYN nos isolados brasileiros de C. raciborskii, demonstrando divergência alopátrica.
The cyanobacterial species Cylindrospermopsis raciborskii belongs to the order Nostocales and has the ability to perform biological nitrogen fixation, synthesize cyanotoxins and also to proliferate in freshwaters to form harmful cyanobacterial blooms. The C. raciborskii population from Brazil is known to produces saxitoxin derivatives (STX), while cylindrospermopsin (CYN), which is commonly detected in isolates from other countries, has thus far not been detected in Brazilian strains. In this study, the production of CYN by two Brazilian isolates of C. raciborskii CENA302 and CENA303, under different nutritional conditions, was evaluated using ELISA immunoassay specific for the detection of CYN. Then, genes involved in the biosynthesis of CYN were searched in the genome of these two strains using PCR amplification with specific primers and subsequent Sanger sequencing, as well as genomic sequencing on the platform HiScan SQ. Furthermore, searches were performed in the two genomes obtained by the platform HiScan SQ of genes involved in the synthesis of several other molecules already described in cyanobacteria, as well as those related to the biological N2 fixation and heterocyte differentiation. Despite the use of different nutritional conditions, no CYN production was detected by the ELISA assay for both cyanobacterial isolates. In the Sanger sequencing, of the nine CYN synthetase gene searched, four were amplified and sequenced in the C. raciborskii strain CENA302 and three in the strain CENA303. These nucleotide sequences were translated into amino acids, and the predicted protein functions and domains confirmed their identity as CYN synthetase genes. The complete genome sequencing of the two strains showed high values of bases quality and high genomic coverage. The search for CYN synthetase genes in the two genomes was performed by mapping reads to reference, showing that some portions of the cluster were contemplated in the genome, representing approximately 10% of CYN cluster. The annotation of regions between the genes described as flanking the CYN cluster showed a gene inversion indicating the occurrence of events that may have caused the loss or dispersion in the genome of this cluster. The annotated genes related to biological N2 fixation and heterocyte differentiation in the CENA302 and CENA303 strains showed high identities with homologous genes from other strains of C. raciborskii. The absence of a few nucleotides in the hetP gene involved in the heterocyte formation perhaps led to the loss of its function in the C. raciborskii CENA303, preventing the differentiation of vegetative cells into heterocyte, since it was not observed the presence of this differentiated cell in any of the nutritional conditions evaluated. All genes of known cyanobacterial molecules searched by mapping reads to reference were not found in the genomes of the C. raciborskii strains CENA302 and CENA303. The results of this study revealed the possibility of being occurring evolutionary events that are leading to loss of the genes responsible for the synthesis of CYN in the C. raciborskii Brazilian isolates, demonstrating allopatric divergence.

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Miranda, Marcela Aparecida Campos Neves. "Efeitos de diferentes intensidades luminosas no crescimento e ecofisiologia de duas cianobactérias formadoras de florações". Universidade Federal de Juiz de Fora, 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/2113.

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Alterações no padrão de distribuição de luz em ambientes aquáticos podem afetar as características fisiológicas das cianobactérias, e com isso, influenciar na ocorrência de suas florações. Microcystis e Cylindrospermopsis estão entre os gêneros mais comuns formadores de florações em sistemas brasileiros. Conhecer e entender os requerimentos por luz e seu efeito no crescimento dessas duas cianobactérias é de fundamental importância para a compreensão e manejo de florações em ambientes aquáticos continentais. Este trabalho buscou avaliar o efeito de diferentes intensidades luminosas (25, 50, 300, 600 μmol de fótons m-2 s-1) na ecofisiologia de M.aeruginosa (cepa MIRF-01) e de C. raciborskii (cepa CYRF-01) e a interação entre uma cepa de M. aeruginosa (MIRF-01) com duas cepas de C. raciborskii (CYRF-01 e T3) em duas intensidades luminosas (50 e 500 μmol de fótons m-2 s-1). Para avaliar a ecofisiologia as células das duas espécies foram previamente aclimatadas por três gerações as intensidades luminosas utilizadas e os parâmetros avaliados foram turbidez, densidade do fluxo de fótons, densidade celular, pigmentos totais, atividade fotossintética e a morfologia das duas espécies. A interação entre as espécies foi verificada através da taxa de crescimento. O aumento na densidade celular ao longo do tempo promoveu aumento da turbidez e reduziu a disponibilidade da intensidade luminosa por volta de 50% em todos os tratamentos, devido ao auto-sombreamento. MIRF apresentou taxa de crescimento maior do que CYRF (0,38 ± 0,015 e 0,29 ± 0,019 respectivamente) em todos os tratamentos. Em ambas as cepas houve um aumento na concentração de pigmentos ao longo do tempo e uma diminuição com o aumento da intensidade luminosa. O aumento na relação carotenóide/clorofila, nas culturas de CYRF cultivadas em alta intensidade luminosa (CYRF-300 e CYRF-600), justifica a mudança na coloração de “verde” viii para “verde-amarelada” das culturas de C. raciborskii. As duas espécies apresentaram taxa de transferência de elétrons semelhantes entre os tratamentos, não sendo verificados mecanismos de dissipação de energia. Em relação a morfologia MIRF apresentou agregação celular em baixas intensidade luminosas (25 e 50 μmol de fótons m-2 s-1) e CYRF apresentaram alterações nos tricomas cultivados as altas intensidade luminosas (300 e 600 μmol de fótons m-2 s-1), levemente curvados com diferenciação nas extremidades e filamentos bifurcados. A interação entre M.aeruginosa e C. raciborskii foi evidente para as cepas coexistentes MIRF e CYRF. Em baixa intensidade luminosa (50 μmol de fótons m-2 s-1), CYRF apresentou menor taxa de crescimento quando na presença de MIRF; em alta intensidade luminosa (500 μmol de fótons m-2 s-1) MIRF apresentou maiores taxas de crescimento quando na presença de CYRF do que quando em monocultura. M.aeruginosa e C. raciborskii quando aclimatadas não apresentaram diferenças em relação à ecofisiologia nas diferentes intensidades luminosas utilizadas. E a interação entre cepas coexistentes pode refletir no crescimento das espécies com a alteração da intensidade luminosa.
Changes in the distribution pattern of light in aquatic environments can affect the physiological characteristics of cyanobacteria and, thus, influence on the occurrence of blooms. Cylindrospermopsis and Microcystis are among the most common bloomforming genera in Brazilian systems. Knowing and understanding the requirements for light and its effect on the growth of these two cyanobacteria are important for the understanding and management of algal blooms in freshwater ecosystems. This study evaluated (1) the effect of different light intensities (25, 50, 300, 600, μmol photons m-2 s-1) on growth, physiology and morphology of the species M. aeruginosa (strain MIRF) and C. raciborskii (strain CYRF) and; (2) the interaction between one strain of M.aeruginosa (MIRF-01) with two strains of C. raciborskii (CYRF-01 and T3) at two light intensities (50 and 500 μmol photons m-2 s-1). Both strains were previously acclimated. Cell density, total pigments, turbidity, density of photon flux, photosynthetic activity and morphology of the two species were analized. The interaction between two species was verified by changes in growth rates. The increase in cell density over time promoted increase in turbidity and reduced the availability of light intensity by about 50% in all treatments, due to self-shading. MIRF showed higher growth rate than CYRF (0.38 ± 0.29 ± 0.015 and 0.019 respectively) in all treatments. There was no difference in the growth rates between treatments for MIRF and CYRF in different light intensities. In both strains, there was an increase in pigment concentration over time and decrease with increasing irradiance. The increase in the ratio carotenoid/chlorophyll-a in cultures grown in high irradiance CYRF (CYRF-300 and CYRF-600) explains the change in color from green to green-yellow of cultures of C. raciborskii. The rapid light curves were similar among treatments, and was not verified x down regulation mechanisms. It was also noted that while MIRF showed cell aggregation at low light intensities (25 and 50 mmol photons.m-2.s-1), CYRF showed morphological changes in the trichomes at high light intensities (300 and 600 μmol photons.m-2.s-1), slightly curved filaments and bifurcate at the ends. The interaction between M.aeruginoa and C.raciborskii was evident for coexisting MIRF and CYRF strains. In low light intensity (50 μmol photons.m-2.s-1), CYRF showed a lower growth rate in the presence of MIRF. In high light-intensity (500 μmol photons.m-2.s-1) MIRF growth rates were higher in the presence of CYRF than in monoculture. When M.aeruginosa and C.raciborskii are acclimated there is no ecophysiology difference in different light intensities. The interaction between coexisting strains may reflect the growth of species in different light intensity.

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47

Mello, Mariana Mendes e. "O papel das interações químicas na ocorrência e dominância de cianobactérias formadoras de florações". Universidade Federal de Juiz de Fora, 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/2153.

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Cianobactérias vêm sendo apontadas como um dos maiores problemas ambientais relacionados à água doce. Esses micro-organismos formadores de florações e potencialmente tóxicos estão relacionados à perda da qualidade da água e até a problemas de saúde em seres humanos. Alta afinidade por nitrogênio, estratégias para estocagem de fósforo e a capacidade de ajustarem sua posição na coluna d’água são algumas vantagens competitivas das cianobactérias sobre outros componentes do fitoplâncton. Mais recentemente, a ocorrência de processos de comunicação química, como alelopatia e quorum sensing, vêm sendo apontados como vantagens competitivas alternativas das cianobactérias. Desta forma, os objetivos do presente trabalho foram: (1) verificar se as espécies Cylindrospermopsis raciborskii e Microcystis aeruginosa interagem quimicamente e se situações de estresse por competição e luz influenciam nessa interação; (2) verificar como a competição entre C. raciborskii e M. aeruginosa pode alterar a morfologia de M. aeruginosa, através da formação de colônias, além de avaliar o papel da co-evolução neste processo. Para tal, experimentos em laboratório foram executados adicionando-se exudatos de culturas de C. raciborskii e M. aeruginosa, sob diferentes condições, em ambas as espécies como alvo. Os resultados apontaram que as cepas de C. raciborskii (CYRF) e M. aeruginosa (MIRF) provenientes do Reservatório do Funil (RJ) apresentaram um maior número de respostas às interações químicas do que cepas provenientes de outros locais. CYRF em estresse por competição produziu possíveis aleloquímicos capazes de inibir o crescimento de MIRF, enquanto MIRF quando cultivada sob estresse por luz (25 μmol fótons m-2s-1) produziu aleloquímicos capazes de inibir o crescimento de CYRF. Ambas as cepas também demonstraram a habilidade de se comunicarem por quorum sensing. Essa comunicação em CYRF induziu a inibição do seu próprio crescimento, enquanto que em MIRF induziu a formação de colônias. Quando a formação de colônia em M. aeruginosa foi testada, foi observado uma possível produção de moléculas para a formação de colônias em MIRF engatilhada pela competição com diferentes cepas de C. raciborskii, e não somente com CYRF. Os resultados apontaram também que, dentre dez cepas de M. aeruginosa testadas, somente MIRF foi capaz de formar colônias quando em contato com o exudato da competição entre CYRF e MIRF. Desta forma, o sinal para formação de colônia foi apontado como cepa-dependente, indicando a importância do papel da co-evolução nas interações químicas entre cianobactérias. Os resultados encontrados sugerem que interações químicas intra e interespecíficas podem desempenhar importante papel, ainda que pouco explorado, na dominância e substituição de espécies de cianobactérias.
Cyanobacteria have been pointed as one of the main problems in freshwater systems. These blooming microorganisms are potentially toxic and their occurrence have been directly related to the lost of water quality and human health problems. High nitrogen affinity, strategies to storage phosphorus and the ability to adjust their position in the water column are some competitive advantages of cyanobacteria over other phytoplankton components. Recently, mechanisms of chemical communication, such as allelopathy and quorum sensing, have been indicated as an alternative advantage of cyanobacteria. The aim of this study was: 1. to evaluate if Cylindrospermopsis raciborskii and Microcystis aeruginosa can interact chemically, and if stressed conditions caused by competition and light can interfere in this relationship; 2. to evaluate how the competition between C. raciborskii and M. aeruginosa can induce morphological variation (colony formation) in M. aeruginosa and how the role of coevaluation. Laboratory experiments were performed and exudates from C. raciborskii and M. aeruginosa, cultivated in different conditions, were added to the same species as target. The results revealed that the strains of C. raciborskii (CYRF) and M. aeruginosa (MIRF), isolated from Funil Reservoir (RJ), showed more responses to chemical interactions than the strains from different places. When CYRF was grown in regular light (100 μmol quanta m-2s-1) and stressed by competition, this strain produced allelochemicals that inhibited the growth of MIRF, while MIRF cultivated in light stress (25 μmol quanta m-2s-1) produced allelochemicals that inhibited the growth of CYRF. It was also observed that both strains have the ability to communicate by quorum sensing. This communication induced growth self-inhibition in CYRF, while it induced colony formation in MIRF. When colony formation was evaluated, the production of inducible molecules to colony formation in MIRF was triggered by the competition with different strains of C. raciborskii, and not only by the competition with CYRF. The results also showed that, among ten strains of M. aeruginosa, only MIRF was able to form colonies when in contact with exudates from competition between CYRF and MIRF. The colony formation signal was pointed as strain-dependent, highlighting the importance of the co-evolution in chemical interactions among cyanobacteria. These results suggest that chemical interactions among species can play an important role, still unexplored, in the dominance and successional pattern of species.

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48

Oliveira, Marina Junqueira Melgaço de. "Efeitos da disponibilidade de luz e limitação de nutrientes sobre a competição entre cepas de Cylindrospermopsis raciborskii e Microcystis aeruginosa". Universidade Federal de Juiz de Fora (UFJF), 2007. https://repositorio.ufjf.br/jspui/handle/ufjf/4001.

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O aumento da ocorrência e dominância de Cylindrospermopsis raciborskii em ecossistemas aquáticos continentais, observado em todo o mundo tem resultado, em muitos casos, na substituição de outras espécies de cianobactérias, como Microcystis aeruginosa. Os fatores relacionados a essa dominância ainda não são bem compreendidos. O objetivo deste trabalho foi avaliar a influência da luz e nutrientes na competição entre C. raciborskii e M. aeruginosa. Foram realizados experimentos em cultivos unialgais visando determinar a dinâmica de absorção de nitrogênio (N) e fósforo (P) por 4 cepas (2 cepas de C. raciborskii, 2 de M. aeruginosa). As habilidades competitivas das duas espécies foram avaliadas em cultivos mistos em 3 condições de intensidade luminosa (alta, média e baixa) e de limitação de N e P. As quatro cepas estudadas apresentaram a mesma dinâmica na assimilação de nutrientes,absorvendo rapidamente N e P (ca. 24hs) e com taxas de crescimento, tempo de duplicação e rendimento máximo da cultura semelhantes. Nos experimentos de competição as cepas de M. aeruginosa foram dominantes na maior intensidade luminosa nas condições P-limitada e controle e na limitação por N apenas no ultimo bloco. Na menor intensidade foi dominante apenas nos dois últimos blocos na condição controle. Na intensidade média foi dominante na condição controle no ultimo bloco, com limitação de fósforo e nitrogênio nos dois últimos blocos. Enquanto que apenas uma cepa C. raciborskii foi dominante na condição controle na menor intensidade luminosa. Na condição N-limitada, C. raciborskii foi dominante apenas na menor intensidade no primeiro bloco e na maior intensidade no segundo bloco de experimentos. Na condição P-limitada, C. raciborskii não foi dominante em nenhum momento. Fica evidente portanto, a influência e interação da disponibilidade de luz e nutrientes na competição entre C. raciborskii e M. aeruginosa, contudo, as respostas são dependentes das cepas, e as generalizações específicas devem ser avaliadas com cuidado.
The increase in occurrence and dominance of the cyanobacteria Cylindrospermopsis raciborskii in freshwater ecosystems, observed worldwide, has resulted, in many cases, in a replacement of other species like Microcystis aeruginosa. The factors related with this dominance are still unknown. The aim of this work was to evaluate the influence of light and nutrients in the competition between C. raciborskii and M. aeruginosa. Experiments with 4 strains (2 strains of C. raciborskii, 2 strains of M. aeruginosa) in unialgal cultures have been accomplished to determine the nitrogen (N) and phosphorus (P) uptake dynamics. Competitive abilities of the two species have been evaluated in mixed cultures under 3 light intensities (high, medium and low) and under N and P limitation. The 4 studied strains presented the same nutrient uptake dynamics, absorbing N and P quickly (ca. 24 hours) and similar growth rates, mean doubling time and maximum yield of the cultures. At competition experiments M. aeruginosa was dominant in P-limited and control conditions under high and medium light intensities. C. raciborskii strains presented different responses: one of them was dominant in all conditions under low light intensity and also N-limited condition under medium light intensity. The other was dominant only in the N-limited and control conditions under low light intensity. It’s then evident the influence of the availability of light and nutrients in the competition between C. raciborskii and M. aeruginosa, however, the responses rely on the strains and specific generalization should be carefully evaluated.

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49

Barros, MÃrio Ubirajara GonÃalves. "ProspecÃÃo de Cylindrospermopsis Raciborskii em ReservatÃrios no CearÃ e Efeitos da DepleÃÃo de Nutrientes na sua ConcentraÃÃo Celular". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9656.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
A qualidade da Ãgua dos reservatÃrios brasileiros vem sendo comprometida devido ao intenso processo de eutrofizaÃÃo. O lanÃamento de esgoto sanitÃrio, a agropecuÃria e a piscicultura intensiva favorecem esse fenÃmeno pela introduÃÃo no meio aquÃtico de altas concentraÃÃes de nutrientes, principalmente o nitrogÃnio e o fÃsforo. A eutrofizaÃÃo da Ãgua prejudica o abastecimento pÃblico pelo fato de favorecer a proliferaÃÃo de cianobactÃrias potencialmente produtora de toxinas. O presente trabalho teve como objetivo realizar um mapeamento das cianobactÃrias potencialmente produtora de toxinas, especificamente a espÃcie Cylindrospermopsis raciborskii, em mananciais utilizados para abastecimento pÃblico no estado do CearÃ. Os dados necessÃrios para a prospecÃÃo do fitoplÃncton nos reservatÃrios do CearÃ foram coletados no laboratÃrio central da Companhia de Ãgua e Esgoto do CearÃ (CAGECE). Avaliou-se tambÃm a influÃncia da depleÃÃo de nutrientes limitantes no desenvolvimento de culturas da C. raciborskii T3. Os experimentos foram realizados utilizando-se como meio de cultivo o ASM-1 e variaÃÃes do mesmo com a retirada de 75 e 50% de fÃsforo e nitrogÃnio da sua composiÃÃo inicial. As culturas foram desenvolvidas em condiÃÃes nÃo axÃnicas, mantidas sob intensidade luminosa constante de 6,75 μ.mol.m-2.s-1 submetidas Ã fotoperÃodo de 12h:12h e temperatura de 24Â2 ÂC. O mapeamento da comunidade fitoplanctÃnica nos reservatÃrios estudados apresentou dominÃncia de cianobactÃrias, frequentemente maiores que 90% do fitoplÃncton total. Com relaÃÃo Ã cianobactÃria C. raciborskii, sua presenÃa foi evidenciada em todos os reservatÃrios estudados, com menor representaÃÃo no aÃude Cedro (30%) e maior no AÃude Carmina (98%). Em todos os aÃudes, exceto o AÃude Cedro, a presenÃa do gÃnero C. raciborskii foi, em mÃdia, maior que 70% durante todo o perÃodo estudado. A dominÃncia dessa espÃcie foi evidenciada em trÃs reservatÃrios: aÃude Acarape do Meio (92%), aÃude Serafim Dias (89%) e aÃude do Coronel (73%) e em dois reservatÃrios, aÃude SÃtios Novos e aÃude Cedro, esta espÃcie nÃo dominou em nenhuma coleta. Os resultados mostraram tambÃm que as culturas com depleÃÃo de nitrogÃnio apresentaram nitidamente menor crescimento com relaÃÃo aos outros experimentos, atingindo a fase estacionÃria mais cedo e com menores concentraÃÃes celulares. JÃ as culturas com depleÃÃo de fÃsforo (75 e 50% P) apresentaram curvas de crescimento mais acentuadas, demonstrando assim que o elemento nitrogÃnio foi limitante para o crescimento da C. raciborskii nas condiÃÃes deste experimento.
The water quality of Brazilian reservoirs has been harmful due to the intense process of eutrophication. Wastewater, agriculture and intensive farming favor this phenomenon by introducing into the aquatic environment high concentrations of nutrients, particularly nitrogen and phosphorus. Eutrophication of water affect the public water supply because induces proliferation of cyanobacteria potentially toxins producer. This study aimed to perform a mapping of cyanobacteria potentially toxins producer, specifically Cylindrospermopsis raciborskii, in reservoirs used for public supply in the state of CearÃ. Data were collected in the central laboratory of Water and Wastewater Company of CearÃ (CAGECE). We also evaluated the effect of depletion of limiting nutrients in the growth of C. raciborskii T3. The experiments were performed using as the culture medium ASM-1 and variations of it with the removal of 75% and 50% of phosphorus and nitrogen from its initial composition. Cultures were grown in axenic conditions and maintained under constant light intensity of 6.75μ.mol.m-2.s-1, subjected to photoperiod of 12h: 12h and 24 Â 2 Â C. The mapping of phytoplankton in reservoirs studied showed dominance of cyanobacteria, often greater than 90% of the total cell concentration. Regarding the cyanobacterium C.raciborskii, its presence was evident in all reservoirs studied, with less representation in Cedro (30%) and higher in Carmina (98%). In all reservoirs except Cedro, the presence of the genus C. raciborskii was on average greater than 70% throughout the study period. The dominance of this species was found in three reservoirs: Acarape do Meio (92%), Serafin Dias (89%) and Coronel (73%) and two reservoirs, Sitios Novos and Cedro, this species did not dominated in any campaign. The results also showed that the nitrogen-depleted cultures showed significantly lower growth relative to other experiments, reaching the stationary phase sooner and at lower cell concentrations. Cultures with depletion of phosphorous (75%P and 50%P) showed more pronounced growth curves, showing that the element nitrogen was limiting the growth of C. raciborskii in this experiment.

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Mazmouz, Rabia. "L' étude de la biosynthèse de trois métabolites secondaires chez Oscillatoria PCC 6506 : cylindrospermopsine, anatoxine-a et cyanobatines". Paris 7, 2012. http://www.theses.fr/2012PA077073.

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Les cyanobactéries, procaryotes photosynthétiques colonisant la plupart des environnements, produisent une large gamme de métabolites secondaires dont des toxines pour l'Homme et les animaux. Il est maintenant reconnu que la présence de cyanotoxines dans l'environnement représente un risque pour la santé. L'équipe s'intéresse particulièrement aux cyanobactéries du genre Oscillatoria dont plusieurs souches sont productrices de cyanotoxines. Grâce au séquençage du génome de la cyanobactérie Oscillatoria PCC 6506, les clusters de gènes de biosynthèse des toxines: cylindrospermopsine et anatoxine-a ont été identifiés. Au cours de mon travail de thèse, je me suis attachée par des approches variées allant de la génomique, la biochimie, la biologie moléculaire à la chimie analytique à la caractérisation moléculaire du cluster cyr de gènes de biosynthèse de la cylindrospermopsine, à la production de cette toxine par le genre Oscillatoria et à l'étude d'une étape de la biosynthèse. Dans un deuxième temps, je me suis attachée à la caractérisation de protéines remarquables appelées polycétides synthases (PKS), impliquées dans la biosynthèse de Panatoxine-a. Afin de caractériser la dernière étape de la biosynthèse, j'ai clone et exprimé le gène anaG chez E. Coli et la cyanobactérie Synechocystis PCC 6803. L'annotation fine du génome montre la présence de plusieurs autres clusters de gènes de biosynthèse de métabolites secondaires dont un codant pour la biosynthèse de peptides ribosomaux appelés cyanobactines. J'ai cloné les gènes ocy présents chez Oscillatoria PCC 6506 et exprimé et purifié les protéines correspondantes afin d'identifier la structure des cyanobactéries produites par l’Oscillatoria PCC 6506
Cyanobacteria, photosynthetic procaryotes colonizing most of the environments, produce a wide range of secondary metabolites among which of toxins for the Man and the animals. It is now recognized that the presence of cyanotoxins in the environment represents a risk for the health. The team is particularly interested in the cyanobacteria of the genus Oscillatoria which are producing of cyanotoxins. Thanks to the sequencing of the genome of Oscillatoria PCC 6506, toxin biosynthesis clusters of genes were identified : cylindrospermopsin and anatoxin-a. During my PhD, I worked by varied approaches going of the genomics, the biochemistry, the molecular biology to the analytical chemistry in the molecular characterization of the cluster of genes cyr of cylindrospermopsin biosynthesis, in the production of this toxin by the genus Oscillatoria and in the study of a step of the biosynthesis. Secondly, 1 worked to the characterization of proteins called polyketides synthases proteins (PKS), involved in anatoxin-a biosynthesis. To characterize the last step of the biosynthesis, I cloned and expressed the anaG gene at E, coli and in the cyanobacteria Synechocystis PCC 6803. The genome annotation showed the presence of several other biosynthesis clusters of genes of secondary metabolites which one coding for the biosynthesis of ribosomal peptides called cyanobactins. I cloned ocy genes present in Oscillatoria PCC 6506 and expressed and purified corresponding proteins to identify the sequences of cyanobactins produced by Oscillatoria PCC 6506

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