Academic literature on the topic 'Tychonema'
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Journal articles on the topic "Tychonema"
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Evseev, Peter, Irina Tikhonova, Andrei Krasnopeev, Ekaterina Sorokovikova, Anna Gladkikh, Oleg Timoshkin, Konstantin Miroshnikov, and Olga Belykh. "Tychonema sp. BBK16 Characterisation: Lifestyle, Phylogeny and Related Phages." Viruses 15, no. 2 (February 5, 2023): 442. http://dx.doi.org/10.3390/v15020442.
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Cyanobacterial expansion is harmful to the environment, the ecology of Lake Baikal and the economy of nearby regions and can be dangerous to people and animals. Since 2011, the process of colonisation of the lake with potentially toxic cyanobacteria belonging to the genus Tychonema has continued. An understanding of the mechanism of successful expansion of Tychonema requires scrutiny of biological and genomic features. Tychonema sp. BBK16 was isolated from the coastal zone of Lake Baikal. The morphology of BBK16 biofilm was studied with light, scanning electron and confocal microscopy. The biofilm is based on filaments of cyanobacteria, which are intertwined like felt; there are also dense fascicles of rope-like twisted filaments that impart heterogeneity to the surface of the biofilm. Genome sequencing, intergenomic comparisons and phylogenetic analyses indicated that Tychonema sp. BBK16 represent a new species related to planktic cyanobacterium Tychonema bourrellyi, isolated from Alpine lentic freshwater. Genome investigation revealed the genes possibly responsible for the mixotrophic lifestyle. The presence of CRISPR-Cas and restriction modification defence mechanisms allowed to suggest the existence of phages infecting Tychonema sp. BBK16. Analysis of CRISPR spacers and prophage-derived regions allowed to suggest related cyanophages. Genomic analysis supported the assumption that mobile elements and horizontal transfer participate in shaping the Tychonema sp. BBK16 genome. The findings of the current research suggest that the aptitude of Tychonema sp. BBK16 for biofilm formation and, possibly, its mixotrophic lifestyle provide adaptation advantages that lead to the successful expansion of this cyanobacterium in the Baikal’s conditions of freshwater lake environments.
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Bauer, Franziska, Michael Stix, Bernadett Bartha-Dima, Juergen Geist, and Uta Raeder. "Spatio-Temporal Monitoring of Benthic Anatoxin-a-Producing Tychonema sp. in the River Lech, Germany." Toxins 14, no. 5 (May 20, 2022): 357. http://dx.doi.org/10.3390/toxins14050357.
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Incidents with toxic benthic cyanobacteria blooms have been increasing recently. In 2019, several dogs were poisoned in the river Lech (Germany) by the benthic anatoxin-a-producing genus Tychonema. To characterize spatial and temporal distribution of potentially toxic Tychonema in this river, a systematic monitoring was carried out in 2020, focusing on the occurrence of the genus, its toxin production and habitat requirements. Tychonema and cyanobacterial community composition in benthic mats and pelagic samples were identified using a combined approach of microscopy and DNA sequencing of the 16S rRNA gene. In addition, anatoxin-a concentrations of selected samples were measured using the ELISA method. The habitat was characterized to assess the ecological requirements and growth conditions of Tychonema. Tychonema mats and anatoxin-a were detected at several sampling sites throughout the entire study period. Toxin concentrations increased with the progression of the vegetation period and with flow direction, reaching values between 0 and 220.5 µg/L. Community composition differed among pelagic and benthic samples, with life zone and substrate condition being the most important factors. The results of this study highlight the importance of monitoring and understanding the factors determining occurrence and toxin production of both pelagic and benthic cyanobacteria due to their relevance for the health of humans and aquatic ecosystems.
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Schwarzenberger, Anke, and Dominik Martin-Creuzburg. "Daphnia’s Adaptive Molecular Responses to the Cyanobacterial Neurotoxin Anatoxin-α Are Maternally Transferred." Toxins 13, no. 5 (April 30, 2021): 326. http://dx.doi.org/10.3390/toxins13050326.
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Cyanobacterial blooms are an omnipresent and well-known result of eutrophication and climate change in aquatic systems. Cyanobacteria produce a plethora of toxic secondary metabolites that affect humans, animals and ecosystems. Many cyanotoxins primarily affect the grazers of phytoplankton, e.g., Daphnia. The neurotoxin anatoxin-α has been reported world-wide; despite its potency, anatoxin-α and its effects on Daphnia have not been thoroughly investigated. Here, we investigated the effects of the anatoxin-α-producing Tychonema on life-history parameters and gene expression of nicotine-acetylcholine receptors (NAR), the direct targets of anatoxin-α, using several D. magna clones. We used juvenile somatic growth rates as a measure of fitness and analyzed gene expression by qPCR. Exposure to 100% Tychonema reduced the clones’ growth rates and caused an up-regulation of NAR gene expression. When 50% of the food consisted of Tychonema, none of the clones were reduced in growth and only one of them showed an increase in NAR gene expression. We demonstrate that this increased NAR gene expression can be maternally transferred and that offspring from experienced mothers show a higher growth rate when treated with 50% Tychonema compared with control offspring. However, the addition of further (anthropogenic) stressors might impair Daphnia’s adaptive responses to anatoxin-α. Especially the presence of certain pollutants (i.e., neonicotinoids), which also target NARs, might reduce Daphnia’s capability to cope with anatoxin-α.
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Fastner, Jutta, Camilla Beulker, Britta Geiser, Anja Hoffmann, Roswitha Kröger, Kinga Teske, Judith Hoppe, et al. "Fatal Neurotoxicosis in Dogs Associated with Tychoplanktic, Anatoxin-a Producing Tychonema sp. in Mesotrophic Lake Tegel, Berlin." Toxins 10, no. 2 (January 31, 2018): 60. http://dx.doi.org/10.3390/toxins10020060.
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In May 2017, at least 12 dogs showed signs of acute neurotoxicosis after swimming in or drinking from Lake Tegel, a mesotrophic lake in Berlin, Germany, and several of the affected dogs died shortly afterwards despite intensive veterinary treatment. Cyanobacterial blooms were not visible at the water surface or the shorelines. However, detached and floating water moss (Fontinalis antipyretica) with high amounts of Tychonema sp., a potential anatoxin-a (ATX) producing cyanobacterium, was found near the beaches where the dogs had been swimming and playing. Necropsies of two of the dogs revealed no specific lesions beside the anamnestic neurotoxicosis. ATX was detected in concentrations up to 8700 µg L−1 in the stomach contents, while other (neuro)toxic substances were not found. In the aqueous fraction of Fontinalis/Tychonema clumps sampled after the casualties, ATX was found in concentrations up to 1870 µg L−1. This is the first report of a dense population of Tychonema sp. in stands of Fontinalis resulting in high ATX contents. This case emphasizes the need for further investigation of potentially toxic, non-bloom forming cyanobacteria in less eutrophic water bodies and underlines the novel challenge of developing appropriate surveillance schemes for respective bathing sites.
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Morone, Janaína, Graciliana Lopes, Marco Preto, Vítor Vasconcelos, and Rosário Martins. "Exploitation of Filamentous and Picoplanktonic Cyanobacteria for Cosmetic Applications: Potential to Improve Skin Structure and Preserve Dermal Matrix Components." Marine Drugs 18, no. 9 (September 22, 2020): 486. http://dx.doi.org/10.3390/md18090486.
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The use of natural products in skin care formulations gained interest as a concern for modern societies. The undesirable side effects of synthetic compounds, as well as the associated environmental hazards, have driven investigation on photosynthetic organisms as sustainable sources of effective and environmentally friendly ingredients. The use of natural extracts in cosmetics has been highlighted and, along with plants and algae, cyanobacteria have come into focus. Due to their low culture demands, high grow rates and ability to produce a wide variability of bioactive metabolites, cyanobacteria emerged as an economic and sustainable base for the cosmetic industry. In this study, we evaluated the potential of ethanol extracts of picocyanobacteria strains of the genera Cyanobium and Synechocystis and filamentous strains of the genera Nodosilinea, Phormidium and Tychonema for skin applications, with focus in the field of anti-aging. The extracts were analyzed for their pigment profile, phenolic content, antioxidant potential, cytotoxicity against keratinocytes (HaCat), fibroblasts (3T3L1), endothelial cells (hCMEC/D3) and capacity to inhibit hyaluronidase (HAase). The total carotenoid content ranged from 118.69 to 383.89 μg g−1 of dry biomass, and the total phenolic content from 1.07 to 2.45 mg GAE g−1. Identified carotenoids consisted of zeaxanthin, lutein, canthaxanthin, echinenone and β-carotene, with zeaxanthin and lutein being the most representative (49.82 and 79.08 μg g−1, respectively). The highest antioxidant potential was found for Phormidium sp. LEGE 05292 and Tychonema sp. LEGE 07196 for superoxide anion radical (O2•−) scavenging (IC50 of 822.70 and 924 μg mL−1, respectively). Low or no cytotoxicity were registered. Regarding HAase inhibition, Tychonema sp. LEGE 07196 and Cyanobium sp. LEGE 07175 showed the best IC50 (182.74 and 208.36 μg mL−1, respectively). In addition, an increase in fibroblast proliferation was registered with these same strains. From this work, the ethanol extracts of the species Tychonema sp. and Cyanobium sp. are particularly interesting for their potential application in anti-aging formulations, once they stimulated fibroblast proliferation and inhibit hyaluronic acid digestion.
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Komárek, Jiří, and Patrizia Albertano. "Cell structure of a planktic cyanoprokaryote, Tychonema bourrellyi." Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 75 (October 27, 1995): 157–66. http://dx.doi.org/10.1127/algol_stud/75/1995/157.
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Shams, S., C. Capelli, L. Cerasino, A. Ballot, D. R. Dietrich, K. Sivonen, and N. Salmaso. "Anatoxin-a producing Tychonema (Cyanobacteria) in European waterbodies." Water Research 69 (February 2015): 68–79. http://dx.doi.org/10.1016/j.watres.2014.11.006.
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Shiels, Browne, Donovan, Murray, and Saha. "Molecular Characterization of Twenty-Five Marine Cyanobacteria Isolated from Coastal Regions of Ireland." Biology 8, no. 3 (August 7, 2019): 59. http://dx.doi.org/10.3390/biology8030059.
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Twenty-five marine cyanobacteria isolated from Irish coasts were characterized based on their morphological characters and 16S rRNA gene sequence analysis. In addition, superoxide dismutase (SOD) and malate dehydrogenase (MDH) isoenzyme banding patterns were used to differentiate two morphologically ambiguous isolates. In this study, six new cyanobacteria-specific primers were designed, and a 16S rRNA gene of twenty-five morphologically diverse cyanobacteria was successfully PCR amplified (1198–1396 bps). Assembled 16S rRNA sequences were used both for a basic local alignment search tool (BLAST) analysis for genus-level identification and to generate a phylogenetic tree, which yielded two major clusters: One with morphologically homogenous cyanobacteria and the other with morphologically very diverse cyanobacteria. Kamptonema okenii and Tychonema decoloratum were isolated from a single field sample of Ballybunion and were originally identified as the same ‘Oscillatoria sp.’ based on preliminary morphological observations. However, an alignment of 16S rRNA gene sequences and SOD and MDH isoenzyme banding pattern analyses helped in differentiating the morphologically-indistinguishable ‘Oscillatoria sp.’. Finally, after a re-evaluation of their morphological characters using modern taxonomic publications, the originally identified ‘Oscillatoria sp.’ were re-identified as Kamptonema okenii and Tychonema decoloratum, thus supporting the polyphasic approach of cyanobacteria characterization.
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Bauer, Franziska, Jutta Fastner, Bernadett Bartha-Dima, Wolfram Breuer, Almuth Falkenau, Christian Mayer, and Uta Raeder. "Mass Occurrence of Anatoxin-a- and Dihydroanatoxin-a-Producing Tychonema sp. in Mesotrophic Reservoir Mandichosee (River Lech, Germany) as a Cause of Neurotoxicosis in Dogs." Toxins 12, no. 11 (November 20, 2020): 726. http://dx.doi.org/10.3390/toxins12110726.
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In August 2019, three dogs died after bathing in or drinking from Mandichosee, a mesotrophic reservoir of the River Lech (Germany). The dogs showed symptoms of neurotoxic poisoning and intoxication with cyanotoxins was considered. Surface blooms were not visible at the time of the incidents. Benthic Tychonema sp., a potential anatoxin-a (ATX)-producing cyanobacterium, was detected in mats growing on the banks, as biofilm on macrophytes and later as aggregations floating on the lake surface. The dogs’ pathological examinations showed lung and liver lesions. ATX and dihydroanatoxin-a (dhATX) were detected by LC-MS/MS in the stomachs of two dogs and reached concentrations of 563 and 1207 µg/L, respectively. Anatoxins (sum of ATX and dhATX, ATXs) concentrations in field samples from Mandichosee ranged from 0.1 µg/L in the open water to 68,000 µg/L in samples containing a large amount of mat material. Other (neuro)toxic substances were not found. A molecular approach was used to detect toxin genes by PCR and to reveal the cyanobacterial community composition by sequencing. Upstream of Mandichosee, random samples were taken from other Lech reservoirs, uncovering Tychonema and ATXs at several sampling sites. Similar recent findings emphasize the importance of focusing on the investigation of benthic toxic cyanobacteria and applying appropriate monitoring strategies in the future.
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Rudi, Knut, Olav M. Skulberg, and Kjetill S. Jakobsen. "Evolution of Cyanobacteria by Exchange of Genetic Material among Phyletically Related Strains." Journal of Bacteriology 180, no. 13 (July 1, 1998): 3453–61. http://dx.doi.org/10.1128/jb.180.13.3453-3461.1998.
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ABSTRACT The cyanobacterial radiation consists of several lineages of phyletically (morphologically and genetically) related organisms. Several of these organisms show a striking resemblance to fossil counterparts. To investigate the molecular mechanisms responsible for stabilizing or homogenizing cyanobacterial characters, we compared the evolutionary rates and phylogenetic origins of the small-subunit rRNA-encoding DNA (16S rDNA), the conserved gene rbcL(encoding d-ribulose 1,5-bisphosphate carboxylase-oxygenase large subunit), and the less conserved gene rbcX. This survey includes four categories of phyletically related organisms: 16 strains of Microcystis, 6 strains of Tychonema, 10 strains of Planktothrix, and 12 strains ofNostoc. Both rbcL and rbcX can be regarded as neutrally evolving genes, with 95 to 100% and 50 to 80% synonymous nucleotide substitutions, respectively. There is generally low sequence divergence within the Microcystis,Tychonema, and Planktothrix categories both forrbcLX and 16S rDNA. The Nostoc category, on the other hand, consists of three genetically clustered lineages for these loci. The 16S rDNA and rbcLX phylogenies are not congruent for strains within the clustered groups. Furthermore, analysis of the phyletic structure for rbcLX indicates recombinational events between the informative sites within this locus. Thus, our results are best explained by a model involving both intergenic and intragenic recombinations. This evolutionary model explains the DNA sequence clustering for the modern species as a result of sequence homogenization (concerted evolution) caused by exchange of genetic material for neutrally evolving genes. The morphological clustering, on the other hand, is explained by structural and functional stability of these characters. We also suggest that exchange of genetic material for neutrally evolving genes may explain the apparent stability of cyanobacterial morphological characters, perhaps over billions of years.
Dissertations / Theses on the topic "Tychonema"
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Mehner, Christian Michael. "Bioactive peptides from the cyanobacterial strains Tychonema sp. and Nostoc insulare." München Verl. Dr. Hut, 2008. http://d-nb.info/992163552/04.
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Shams, Shiva. "Diversity, impact and fate of cyanobacterial toxins in freshwater ecosytems." Doctoral thesis, country:DE, 2015. http://hdl.handle.net/10449/24890.
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Massive proliferations of cyanobacteria (bloom) are common in aquatic environments worldwide. These blooms are often toxic due to the presence of hepatotoxins or neurotoxins and have become a worldwide environmental problem. Various incidents of animal and human poisonings have been
attributed to these toxins. Therefore, monitoring of potentially toxic cyanobacteria and the associated toxins need to be investigated routinely in each water body. In the first part of present study, LC-MS methods were applied for identifying and quantifying cyanotoxins diversity in Lake Garda. Anatoxin-a (ATX) and microcystins (MC) were always present in this lake with a different seasonal pattern. ATX represented an early summer peak, while MC showed a typical late summer-early autumn peak.The results of toxin analysis also revealed the
presence of 5 variants of MC in this lake, but the variants MC-RRdm was always dominant over the others. In another chapter of this thesis the kinetic aspects of MC transfer from Planktothrix rubescens to Daphnia magna was investigated. Models of MC accumulation obtained from this part of study differed largely as a result of the duration of exposure and initial MC concentrations used. Within the first 24 h of exposure, MC accumulation in D. magna was linear, irrespective of the initial densities
of toxic P. rubescens and MC concentrations. After 48h of exposure, MC accumulation in D. magna showed an exponential pattern. In the last part of this study, the taxonomic identification of new Oscillatoriales was carried out adopting a polyphasic approach and new potential ATX producers were screened through chemical characterization and identification of specific toxins encoding genes. The analyses were made on
several strains isolated from environmental samples collected in Lake Garda. The results allowed identifying a new ATX producer, Tychonema bourrellyi. This is the first
discovery of a planktonic genus belonging to the Oscillatoriales able to produce ATX
Book chapters on the topic "Tychonema"
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"16. In s. Tychonem thaumaturgum Episcopum Amathountis et in s. Pagcharium martyrem." In Codex Lesbiacus Leimonos 11. Berlin, New York: De Gruyter, 2010. http://dx.doi.org/10.1515/9783110221305.242.
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