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1
Nakayama, Takuro, Mami Nomura, Yoshihito Takano, Goro Tanifuji, Kogiku Shiba, Kazuo Inaba, Yuji Inagaki e Masakado Kawata. "Single-cell genomics unveiled a cryptic cyanobacterial lineage with a worldwide distribution hidden by a dinoflagellate host". Proceedings of the National Academy of Sciences 116, n. 32 (24 giugno 2019): 15973–78. http://dx.doi.org/10.1073/pnas.1902538116.
Testo completoAbstract (sommario):
Cyanobacteria are one of the most important contributors to oceanic primary production and survive in a wide range of marine habitats. Much effort has been made to understand their ecological features, diversity, and evolution, based mainly on data from free-living cyanobacterial species. In addition, symbiosis has emerged as an important lifestyle of oceanic microbes and increasing knowledge of cyanobacteria in symbiotic relationships with unicellular eukaryotes suggests their significance in understanding the global oceanic ecosystem. However, detailed characteristics of these cyanobacteria remain poorly described. To gain better insight into marine cyanobacteria in symbiosis, we sequenced the genome of cyanobacteria collected from a cell of a pelagic dinoflagellate that is known to host cyanobacterial symbionts within a specialized chamber. Phylogenetic analyses using the genome sequence revealed that the cyanobacterium represents an underdescribed lineage within an extensively studied, ecologically important group of marine cyanobacteria. Metagenomic analyses demonstrated that this cyanobacterial lineage is globally distributed and strictly coexists with its host dinoflagellates, suggesting that the intimate symbiotic association allowed the cyanobacteria to escape from previous metagenomic studies. Furthermore, a comparative analysis of the protein repertoire with related species indicated that the lineage has independently undergone reductive genome evolution to a similar extent as Prochlorococcus, which has the most reduced genomes among free-living cyanobacteria. Discovery of this cyanobacterial lineage, hidden by its symbiotic lifestyle, provides crucial insights into the diversity, ecology, and evolution of marine cyanobacteria and suggests the existence of other undiscovered cryptic cyanobacterial lineages.
2
Hurley, Sarah J., Boswell A. Wing, Claire E. Jasper, Nicholas C. Hill e Jeffrey C. Cameron. "Carbon isotope evidence for the global physiology of Proterozoic cyanobacteria". Science Advances 7, n. 2 (gennaio 2021): eabc8998. http://dx.doi.org/10.1126/sciadv.abc8998.
Testo completoAbstract (sommario):
Ancestral cyanobacteria are assumed to be prominent primary producers after the Great Oxidation Event [≈2.4 to 2.0 billion years (Ga) ago], but carbon isotope fractionation by extant marine cyanobacteria (α-cyanobacteria) is inconsistent with isotopic records of carbon fixation by primary producers in the mid-Proterozoic eon (1.8 to 1.0 Ga ago). To resolve this disagreement, we quantified carbon isotope fractionation by a wild-type planktic β-cyanobacterium (Synechococcus sp. PCC 7002), an engineered Proterozoic analog lacking a CO2-concentrating mechanism, and cyanobacterial mats. At mid-Proterozoic pH and pCO2 values, carbon isotope fractionation by the wild-type β-cyanobacterium is fully consistent with the Proterozoic carbon isotope record, suggesting that cyanobacteria with CO2-concentrating mechanisms were apparently the major primary producers in the pelagic Proterozoic ocean, despite atmospheric CO2 levels up to 100 times modern. The selectively permeable microcompartments central to cyanobacterial CO2-concentrating mechanisms (“carboxysomes”) likely emerged to shield rubisco from O2 during the Great Oxidation Event.
3
Kollmen, Jonas, e Dorina Strieth. "The Beneficial Effects of Cyanobacterial Co-Culture on Plant Growth". Life 12, n. 2 (31 gennaio 2022): 223. http://dx.doi.org/10.3390/life12020223.
Testo completoAbstract (sommario):
Cyanobacteria are ubiquitous phototrophic prokaryotes that find a wide range of applications in industry due to their broad product spectrum. In this context, the application of cyanobacteria as biofertilizers and thus as an alternative to artificial fertilizers has emerged in recent decades. The benefit is mostly based on the ability of cyanobacteria to fix elemental nitrogen and make it available to the plants in a usable form. However, the positive effects of co-cultivating plants with cyanobacteria are not limited to the provision of nitrogen. Cyanobacteria produce numerous secondary metabolites that can be useful for plants, for example, they can have growth-promoting effects or increase resistance to plant diseases. The effects of biotic and abiotic stress can as well be reduced by many secondary metabolites. Furthermore, the biofilms formed by the cyanobacteria can lead to improved soil conditions, such as increased water retention capacity. To exchange the substances mentioned, cyanobacteria form symbioses with plants, whereby the strength of the symbiosis depends on both partners, and not every plant can form symbiosis with every cyanobacterium. Not only the plants in symbiosis benefit from the cyanobacteria, but also vice versa. This review summarizes the beneficial effects of cyanobacterial co-cultivation on plants, highlighting the substances exchanged and the strength of cyanobacterial symbioses with plants. A detailed explanation of the mechanism of nitrogen fixation in cyanobacterial heterocysts is given. Finally, a summary of possible applications of co-cultivation in the (agrar-)industry is given.
4
Rangel, Luciana M., Lúcia H. S. Silva, Elisabeth J. Faassen, Miquel Lürling e Kemal Ali Ger. "Copepod Prey Selection and Grazing Efficiency Mediated by Chemical and Morphological Defensive Traits of Cyanobacteria". Toxins 12, n. 7 (21 luglio 2020): 465. http://dx.doi.org/10.3390/toxins12070465.
Testo completoAbstract (sommario):
Phytoplankton anti-grazer traits control zooplankton grazing and are associated with harmful blooms. Yet, how morphological versus chemical phytoplankton defenses regulate zooplankton grazing is poorly understood. We compared zooplankton grazing and prey selection by contrasting morphological (filament length: short vs. long) and chemical (saxitoxin: STX- vs. STX+) traits of a bloom-forming cyanobacterium (Raphidiopsis) offered at different concentrations in mixed diets with an edible phytoplankton to a copepod grazer. The copepod selectively grazed on the edible prey (avoidance of cyanobacteria) even when the cyanobacterium was dominant. Avoidance of the cyanobacterium was weakest for the “short STX-” filaments and strongest for the other three strains. Hence, filament size had an effect on cyanobacterial avoidance only in the STX- treatments, while toxin production significantly increased cyanobacterial avoidance regardless of filament size. Moreover, cyanobacterial dominance reduced grazing on the edible prey by almost 50%. Results emphasize that the dominance of filamentous cyanobacteria such as Raphidiopsis can interfere with copepod grazing in a trait specific manner. For cyanobacteria, toxin production may be more effective than filament size as an anti-grazer defense against selectively grazing zooplankton such as copepods. Our results highlight how multiple phytoplankton defensive traits interact to regulate the producer-consumer link in plankton ecosystems.
5
Rajabpour, Nooshin, Bahareh Nowruzi e Maryam Ghobeh. "Investigation of the toxicity, antioxidant and antimicrobial activities of some cyanobacterial strains isolated from different habitats". Acta Biologica Slovenica 62, n. 2 (1 dicembre 2019): 4–12. http://dx.doi.org/10.14720/abs.62.2.15753.
Testo completoAbstract (sommario):
Cyanobacteria are known as a source of fine chemicals, renewable fuels, and toxic compounds. The present study aimed at evaluating the toxicity and antioxidant and antimicrobial activities of four cyanobacterial strains isolated from different habitats. Due to the lack of information regarding the relationship between toxicity and biological activity of the cyanobacteria in terrestrial and aquatic ecosystems of Iran, we decided to conduct a preliminary study on the cyanobacterial strains in order to identify the potentially toxic cyanobacteria strains. In this respect, biosynthesis genes related to cyanobacterial toxins, anatoxins (anaC gene), nodularins (ndaF gene) and microcystins (mcyG gene) were amplified. In addition, antioxidant, antimicrobial and biochemical properties of cyanobacterial strains have also been evaluated. The results of the molecular analysis demonstrated that only Fischerella sp. contained the microcystins (mcyG) gene. In fact, this strain encounters numerous predators in its habitat, therefore antibacterial and antioxidant metabolites found in this strain have thought to play an important role in defense mechanisms. This case is the documentation of toxicity and promotion of biological activities of a soil cyanobacterium regarding survival in competitive ecological niches.
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Foster, Rachel A., e Jonathan P. Zehr. "Diversity, Genomics, and Distribution of Phytoplankton-Cyanobacterium Single-Cell Symbiotic Associations". Annual Review of Microbiology 73, n. 1 (8 settembre 2019): 435–56. http://dx.doi.org/10.1146/annurev-micro-090817-062650.
Testo completoAbstract (sommario):
Cyanobacteria are common in symbiotic relationships with diverse multicellular organisms (animals, plants, fungi) in terrestrial environments and with single-celled heterotrophic, mixotrophic, and autotrophic protists in aquatic environments. In the sunlit zones of aquatic environments, diverse cyanobacterial symbioses exist with autotrophic taxa in phytoplankton, including dinoflagellates, diatoms, and haptophytes (prymnesiophytes). Phototrophic unicellular cyanobacteria related to Synechococcus and Prochlorococcus are associated with a number of groups. N2-fixing cyanobacteria are symbiotic with diatoms and haptophytes. Extensive genome reduction is involved in the N2-fixing endosymbionts, most dramatically in the unicellular cyanobacteria associated with haptophytes, which have lost most of the photosynthetic apparatus, the ability to fix C, and the tricarboxylic acid cycle. The mechanisms involved in N2-fixing symbioses may involve more interactions beyond simple exchange of fixed C for N. N2-fixing cyanobacterial symbioses are widespread in the oceans, even more widely distributed than the best-known free-living N2-fixing cyanobacteria, suggesting they may be equally or more important in the global ocean biogeochemical cycle of N.Despite their ubiquitous nature and significance in biogeochemical cycles, cyanobacterium-phytoplankton symbioses remain understudied and poorly understood.
7
Caraco, N. F., e R. Miller. "Effects of CO2 on competition between a cyanobacterium and eukaryotic phytoplankton". Canadian Journal of Fisheries and Aquatic Sciences 55, n. 1 (1 gennaio 1998): 54–62. http://dx.doi.org/10.1139/f97-202.
Testo completoAbstract (sommario):
To distinguish whether there is a causal link between cyanobacterial dominance and low CO2 and (or) the associated high pH, we ran duplicate competition experiments using a factorial design of CO2 by alkalinity. In various treatments, three concentrations of alkalinity (ca. 50, 500, and 5000 µequiv. ·L-1) and CO2 (ca. 1.3, 13, and 130 µM) generated three pH values (ca. 7, 8, and 9). At the end of about a 1-week incubation, Aphanizomenon flos aquae was the only cyanobacterium present, while the chlorophytes Scenedesmus and Selenastrum along with unidentified flagellates comprised the eukaryotic phytoplankton. The treatments had a dramatic effect on cyanobacterial biomass, which varied from >90% to 0% of the total phytoplankton biomass across treatments. Variation in percent cyanobacteria was better related to pH than to CO2. At pH 8 and 9, percent cyanobacteria was relatively high at all CO2 concentrations. Only at pH 7 was percent cyanobacteria negatively related to CO2 concentration. These results demonstrate both direct and indirect effects of CO2 on cyanobacterial dominance but suggest that, for A. flos aquae, the indirect impact of CO2 (pH alteration) is most important. The impact of CO2 on this cyanobacterium, therefore, depends on the alkalinity of the system.
8
Deng, Ming-De, e John R. Coleman. "Ethanol Synthesis by Genetic Engineering in Cyanobacteria". Applied and Environmental Microbiology 65, n. 2 (1 febbraio 1999): 523–28. http://dx.doi.org/10.1128/aem.65.2.523-528.1999.
Testo completoAbstract (sommario):
ABSTRACT Cyanobacteria are autotrophic prokaryotes which carry out oxygenic photosynthesis and accumulate glycogen as the major form of stored carbon. In this research, we introduced new genes into a cyanobacterium in order to create a novel pathway for fixed carbon utilization which results in the synthesis of ethanol. The coding sequences of pyruvate decarboxylase (pdc) and alcohol dehydrogenase II (adh) from the bacterium Zymomonas mobilis were cloned into the shuttle vector pCB4 and then used to transform the cyanobacterium Synechococcus sp. strain PCC 7942. Under control of the promoter from the rbcLS operon encoding the cyanobacterial ribulose-1,5-bisphosphate carboxylase/oxygenase, thepdc and adh genes were expressed at high levels, as demonstrated by Western blotting and enzyme activity analyses. The transformed cyanobacterium synthesized ethanol, which diffused from the cells into the culture medium. As cyanobacteria have simple growth requirements and use light, CO2, and inorganic elements efficiently, production of ethanol by cyanobacteria is a potential system for bioconversion of solar energy and CO2 into a valuable resource.
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Olsson-Francis, Karen, Rosa de la Torre e Charles S. Cockell. "Isolation of Novel Extreme-Tolerant Cyanobacteria from a Rock-Dwelling Microbial Community by Using Exposure to Low Earth Orbit". Applied and Environmental Microbiology 76, n. 7 (12 febbraio 2010): 2115–21. http://dx.doi.org/10.1128/aem.02547-09.
Testo completoAbstract (sommario):
ABSTRACT Many cyanobacteria are known to tolerate environmental extremes. Motivated by an interest in selecting cyanobacteria for applications in space, we launched rocks from a limestone cliff in Beer, Devon, United Kingdom, containing an epilithic and endolithic rock-dwelling community of cyanobacteria into low Earth orbit (LEO) at a height of approximately 300 kilometers. The community was exposed for 10 days to isolate cyanobacteria that can survive exposure to the extreme radiation and desiccating conditions associated with space. Culture-independent (16S rRNA) and culture-dependent methods showed that the cyanobacterial community was composed of Pleurocapsales, Oscillatoriales, and Chroococcales. A single cyanobacterium, a previously uncharacterized extremophile, was isolated after exposure to LEO. We were able to isolate the cyanobacterium from the limestone cliff after exposing the rock-dwelling community to desiccation and vacuum (0.7 � 10−3 kPa) in the laboratory. The ability of the organism to survive the conditions in space may be linked to the formation of dense colonies. These experiments show how extreme environmental conditions, including space, can be used to select for novel microorganisms. Furthermore, it improves our knowledge of environmental tolerances of extremophilic rock-dwelling cyanobacteria.
10
Dash, Sidhartha Kumar, Jitendra Kumar Pandey, Mrutyunjay Jena e Basanti Biswal. "Effect of Heat Stress and the Recovery Potential of Heterocystous Cyanobacterium, Anabaena iyengarii Bharadwaja 1935". Journal of Pure and Applied Microbiology 14, n. 4 (16 dicembre 2020): 2467–76. http://dx.doi.org/10.22207/jpam.14.4.24.
Testo completoAbstract (sommario):
Cyanobacteria, the major photosynthetic organisms, cover a large surface area of this planet. These organisms, being photosynthetic, have the capacity for sequestration of atmospheric carbon dioxide, a significant greenhouse gas that causes global warming. In this work, we have collected, developed pure culture, and identified 25 cyanobacterial species from semi arid agricultural rice fields of western Odisha with the high-temperature environmental setting. The purpose was to screen the cyanobacteria that can survive and grow at high temperatures with high photosynthetic efficiency. Cyanobacteria belong to genera Nostoc, Anabaena, Calothrix, and Hapalosiphon are observed to survive at 45°C. Among the cyanobacterial species, Anabaena iyengarii 17-SKD-2014 was found to exhibit higher growth, protein content, photosynthetic pigments, and photosynthetic O2 evolution at 45°C in comparison to other cyanobacterial isolates. Further, this cyanobacterium was grown at 50°C to analyze the cellular viability, and only up to ninth day incubated culture could recover from high-temperature stress after transferring to 25°C. Even though this indigenous cyanobacterial species failed to survive at 50°C in the laboratory conditions beyond a time limit, but this could be biotechnologically manipulated for effective carbon dioxide sequestration contributing to minimization of global warming.
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Sathyananth, M., e T. Leon Stephan Raj. "An Overview of Cyanobacterial Contributions to Agriculture". Asian Research Journal of Agriculture 17, n. 2 (7 giugno 2024): 363–80. http://dx.doi.org/10.9734/arja/2024/v17i2458.
Testo completoAbstract (sommario):
Purpose: This paper reviews the diverse agricultural applications of cyanobacteria for improving soil health, plant growth, and agricultural sustainability. Research Method: The paper provides a literature review summarizing recent research on cyanobacteria's roles in soil aggregation, biofertilization, abiotic/biotic stress tolerance, yield improvements, carbon sequestration, and bioremediation. Both laboratory studies and field trials evaluating cyanobacteria's effects on soil properties and plant growth are discussed. Findings: Cyanobacteria can enhance soil structure, provide fixed nitrogen, mitigate salinity stress, increase crop yields, and sequester carbon. Their stress adaptations, antimicrobial metabolites, and synergies with plants and microbes underpin many benefits. However, translating laboratory research into effective field inoculants remains challenging. Research Limitation: Variability in effectiveness across cyanobacterial strains, plant species, and environments limits current understanding. More field testing is needed along with assessment of potentially negative impacts. Originality/Value: This review highlights promising areas for cyanobacteria to promote agricultural sustainability while identifying knowledge gaps in genetics, plant-microbe interactions, and soil ecology that require further study. It emphasizes the need for locally-adapted, integrated solutions leveraging cyanobacteria's multifunctional traits.
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Stuart, Rhona K., Eric R. A. Pederson, Philip D. Weyman, Peter K. Weber, Ulla Rassmussen e Christopher L. Dupont. "Bidirectional C and N transfer and a potential role for sulfur in an epiphytic diazotrophic mutualism". ISME Journal 14, n. 12 (19 agosto 2020): 3068–78. http://dx.doi.org/10.1038/s41396-020-00738-4.
Testo completoAbstract (sommario):
Abstract In nitrogen-limited boreal forests, associations between feathermoss and diazotrophic cyanobacteria control nitrogen inputs and thus carbon cycling, but little is known about the molecular regulators required for initiation and maintenance of these associations. Specifically, a benefit to the cyanobacteria is not known, challenging whether the association is a nutritional mutualism. Targeted mutagenesis of the cyanobacterial alkane sulfonate monooxygenase results in an inability to colonize feathermosses by the cyanobacterium Nostoc punctiforme, suggesting a role for organic sulfur in communication or nutrition. Isotope probing paired with high-resolution imaging mass spectrometry (NanoSIMS) demonstrated bidirectional elemental transfer between partners, with carbon and sulfur both being transferred to the cyanobacteria, and nitrogen transferred to the moss. These results support the hypothesis that moss and cyanobacteria enter a mutualistic exosymbiosis with substantial bidirectional material exchange of carbon and nitrogen and potential signaling through sulfur compounds.
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Kirkwood, A. E., C. Nalewajko e R. R. Fulthorpe. "The impacts of cyanobacteria on pulp-and-paper wastewater toxicity and biodegradation of wastewater contaminants". Canadian Journal of Microbiology 51, n. 7 (1 luglio 2005): 531–40. http://dx.doi.org/10.1139/w05-030.
Testo completoAbstract (sommario):
This study investigated the effects of cyanobacteria from pulp-and-paper waste-treatment systems on biological toxicity removal and biodegradation of certain wastewater contaminants. In field and batch studies, using the Microtox®assay, cyanobacterial biomass and final wastewater toxicity were significantly correlated. In softwood-based wastewater, a decrease in toxicity was negatively correlated with cyanobacterial biomass, but the correlation was positive in hardwood-based wastewater. In the softwood-based wastewater, toxicity remained higher in the light than it was in the dark, whereas in hardwood-based wastewater, toxicity was lower in the light than it was in the dark. All of these results were light-dependent, suggesting that the photosynthetic growth of cyanobacteria is required to induce significant effects. When grown in mixed cultures with bacterial degraders, cyanobacteria from pulp-and-paper waste-treatment systems generally impeded the biodegradation of the wastewater contaminants phenol and dichloroacetate (DCA). However, there was one case where the cyanobacterium Phormidium insigne improved the bacterial degradation of DCA. Doubling inorganic nutrient concentrations did not improve phenol or DCA biodegradation in the majority of cases, indicating that nutrient competition is not a major factor. These data suggest that cyanobacteria play an important role during the biological treatment of contaminants, and, hence, toxicity removal in pulp-and-paper waste-treatment systems.Key words: cyanobacteria, heterotrophic bacteria, biodegradation, pulp and paper waste-treatment, wastewater toxicity.
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Watanabe, Tomoaki, e Tokumasa Horiike. "The Evolution of Molybdenum Dependent Nitrogenase in Cyanobacteria". Biology 10, n. 4 (14 aprile 2021): 329. http://dx.doi.org/10.3390/biology10040329.
Testo completoAbstract (sommario):
Nitrogen fixation plays a crucial role in the nitrogen cycle by helping to convert nitrogen into a form usable by other organisms. Bacteria capable of fixing nitrogen are found in six phyla including Cyanobacteria. Molybdenum dependent nitrogenase (nif) genes are thought to share a single origin as they have homologs in various phyla. However, diazotrophic bacteria have a mosaic distribution within the cyanobacterial lineage. Therefore, the aim of this study was to determine the cause of this mosaic distribution. We identified nif gene operon structures in the genomes of 85 of the 179 cyanobacterial strains for which whole genome sequences were available. Four nif operons were conserved in each diazotroph Cyanobacterium, although there were some gene translocations and insertions. Phylogenetic inference of these genes did not reveal horizontal gene transfer from outside the phylum Cyanobacteria. These results support the hypothesis that the mosaic distribution of diazotrophic bacteria in the cyanobacterial lineage is the result of the independent loss of nif genes inherited from common cyanobacterial ancestors in each lineage.
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Águila-Carricondo, Pilar, Raúl Román, José Ignacio Marín-Guirao, Yolanda Cantón e Miguel de Cara. "Native Biocrust Cyanobacteria Strains Showing Antagonism against Three Soilborne Pathogenic Fungi". Pathogens 13, n. 7 (11 luglio 2024): 579. http://dx.doi.org/10.3390/pathogens13070579.
Testo completoAbstract (sommario):
The biocontrol potential of three native soil cyanobacteria from biological soil crusts (Nostoc commune, Scytonema hyalinum, and Tolypothrix distorta) was tested by means of in vitro mycelial growth inhibition assays for eighteen cyanobacteria-based products against three phytopathogenic soilborne fungi (Phytophthora capsici, Pythium aphanidermatum, and Fusarium oxysporum f. sp. radicis-cucumerinum). Three cyanobacteria-based production factors were considered: (i) cyanobacterium strain, (ii) cyanobacterial culture growth phase, and (iii) different post-harvest treatments: raw cultures, cyanobacterial filtrates, and cyanobacterial extracts. Results showed that any of the factors considered are key points for successfully inhibiting fungal growth. N. commune showed the highest growth inhibition rates for the three phytopathogens; stationary phase treatments produced higher inhibition percentages than logarithmic ones; and all the post-harvest treatments of N. commune at the stationary phase inhibited the growth of P. capsici, up to 77.7%. Thus, N. commune products were tested in planta against P. capsici, but none of the products showed efficacy in delaying the onset nor reducing the damage due to P. capsici, demonstrating the complexity of the in planta assay’s success and encouraging further research to design an appropriate scaling up methodology.
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Koval, Ekaterina V., e Svetlana Yu Ogorodnikova. "The prospect of using the cyanobacterium Nostoc muscorum to improve vital activity of barley seedlings by various methods of seed treatment". BIO Web of Conferences 36 (2021): 04005. http://dx.doi.org/10.1051/bioconf/20213604005.
Testo completoAbstract (sommario):
The influence of the cyanobacterium Nostoc muscorum on vital activity of barley seedlings of the species Novichok was researched. In the experiments different ways of cyanobacterial treatment were used: introducing microorganisms in the growth medium and pre-sowing inoculation of barley seeds with cyanobacteria. The influence of cyanobacterial treatment on biochemical indices and linear growth of barley plants was assessed. The share of plastid pigments and intensity of the processes of lipid peroxidation were assessed in a spectrophotometric way, standard methods were applied. It was stated that Nostoc muscorum has a phytostimulating effect which consists in inhibiting oxidation processes in barley cells, accumulating substances with antioxidative activity, and activating growth processes. Pre-sowing inoculation of barley seeds with cyanobacteria is the most effective one.
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Douglas, Angela E., e John A. Raven. "Genomes at the interface between bacteria and organelles". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, n. 1429 (29 gennaio 2003): 5–18. http://dx.doi.org/10.1098/rstb.2002.1188.
Testo completoAbstract (sommario):
The topic of the transition of the genome of a free–living bacterial organism to that of an organelle is addressed by considering three cases. Two of these are relatively clear–cut as involving respectively organisms (cyanobacteria) and organelles (plastids). Cyanobacteria are usually free–living but some are involved in symbioses with a range of eukaryotes in which the cyanobacterial partner contributes photosynthesis, nitrogen fixation, or both of these. In several of these symbioses the cyanobacterium is vertically transmitted, and in a few instances, sufficient unsuccessful attempts have been made to culture the cyanobiont independently for the association to be considered obligate for the cyanobacterium. Plastids clearly had a cyanobacterial ancestor but cannot grow independently of the host eukaryote. Plastid genomes have at most 15% of the number of genes encoded by the cyanobacterium with the smallest number of genes; more genes than are retained in the plastid genome have been transferred to the eukaryote nuclear genome, while the rest of the cyanobacterial genes have been lost. Even the most cyanobacteria–like plastids, for example the ‘cyanelles’ of glaucocystophyte algae, are functionally and genetically very similar to other plastids and give little help in indicating intermediates in the evolution of plastids. The third case considered is the vertically transmitted intracellular bacterial symbionts of insects where the symbiosis is usually obligate for both partners. The number of genes encoded by the genomes of these obligate symbionts is intermediate between that of organelles and that of free–living bacteria, and the genomes of the insect symbionts also show rapid rates of sequence evolution and AT (adenine, thymine) bias. Genetically and functionally, these insect symbionts show considerable similarity to organelles.
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Wu, Tianhao, Ran Dai, Zhaosheng Chu e Jing Cao. "Rapid Recovery of Buoyancy in Eutrophic Environments Indicates That Cyanobacterial Blooms Cannot Be Effectively Controlled by Simply Collapsing Gas Vesicles Alone". Water 15, n. 10 (17 maggio 2023): 1898. http://dx.doi.org/10.3390/w15101898.
Testo completoAbstract (sommario):
Many aquatic ecosystems are seriously threatened by cyanobacteria blooms; gas vesicles enable cyanobacteria to form harmful cyanobacterial blooms rapidly. Many lake managers try to control cyanobacterial blooms by collapsing gas vesicle, but it is still unclear whether gas vesicle recovery will cause this method to fail. Through the culture experiments of three cyanobacteria, it was found that all cyanobacteria with collapsed gas vesicles can rapidly regain buoyancy in a few days under nutrient-sufficient environments, and average gas vesicle content was even 9% higher than initially. In contrast, buoyancy recovery of all cyanobacteria under nutrient-limited environments was significantly worse. After culture experiments, the average gas vesicle content of all cyanobacteria in phosphorus-limited environments only reach 49% of the initial value. The gas vesicle content of two non-nitrogen-fixing cyanobacteria in nitrogen-limited environments only reached 38% of initial value. The buoyancy of cyanobacteria in different tropic levels was similar to the gas vesicle content. These results indicate that collapsing gas vesicles can only control cyanobacterial blooms in the short-term. To control cyanobacterial blooms in the long-term, in deep lakes, lake managers should discharge gas vesicles’ collapsed cyanobacteria into deep water. In shallow lakes, the disruption of gas vesicles must be combined with nutrient control measures to effectively control cyanobacteria blooms.
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Novis, Phil M., Jackie Aislabie, Susan Turner e Malcolm McLeod. "Chlorophyta, Xanthophyceae and Cyanobacteria in Wright Valley, Antarctica". Antarctic Science 27, n. 5 (22 aprile 2015): 439–54. http://dx.doi.org/10.1017/s0954102015000164.
Testo completoAbstract (sommario):
AbstractWright Valley, Victoria Land contains numerous aquatic habitats suitable for the growth of algae in summer. Excepting diatoms and lichen phycobionts, algal diversity and distribution in the valley was documented. Using cultures and environmental cloning eight cyanobacterial and 14 eukaryotic species were revealed. The cyanobacterium Microcoleus vaginatus and the chlorophycean Chlorococcum sp. 1 were the most common, both occurring in more than one habitat (ponds, soils or streams). Ponds harboured the most diverse communities. Habitat specialization was rare. Chlamydomonads were not found outside ponds, but species capable of zoospore production were able to colonize ponds and soils. Nostocalean cyanobacteria were not detected. Results suggest dispersal within and between valleys, with little evidence of Antarctic endemism. All but one cyanobacterium with similar internally transcribed spacer (ITS) length to clones from Miers Valley proved to be different species when 16S rRNA gene sequences were also considered; thus, ITS length is unreliable for assessing identity and biogeography of these cyanobacteria. Comparison with a 454 16S rRNA gene soil dataset from Wright Valley indicated the occurrence of only one of the cyanobacterial species, the distribution of which may be limited by salinity.
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Harwood, Thomas V., Esthefani G. Zuniga, HoJun Kweon e Douglas D. Risser. "The cyanobacterial taxis protein HmpF regulates type IV pilus activity in response to light". Proceedings of the National Academy of Sciences 118, n. 12 (15 marzo 2021): e2023988118. http://dx.doi.org/10.1073/pnas.2023988118.
Testo completoAbstract (sommario):
Motility is ubiquitous in prokaryotic organisms including the photosynthetic cyanobacteria where surface motility powered by type 4 pili (T4P) is common and facilitates phototaxis to seek out favorable light environments. In cyanobacteria, chemotaxis-like systems are known to regulate motility and phototaxis. The characterized phototaxis systems rely on methyl-accepting chemotaxis proteins containing bilin-binding GAF domains capable of directly sensing light, and the mechanism by which they regulate the T4P is largely undefined. In this study we demonstrate that cyanobacteria possess a second, GAF-independent, means of sensing light to regulate motility and provide insight into how a chemotaxis-like system regulates the T4P motors. A combination of genetic, cytological, and protein–protein interaction analyses, along with experiments using the proton ionophore carbonyl cyanide m-chlorophenyl hydrazine, indicate that the Hmp chemotaxis-like system of the model filamentous cyanobacterium Nostoc punctiforme is capable of sensing light indirectly, possibly via alterations in proton motive force, and modulates direct interaction between the cyanobacterial taxis protein HmpF, and Hfq, PilT1, and PilT2 to regulate the T4P motors. Given that the Hmp system is widely conserved in cyanobacteria, and the finding from this study that orthologs of HmpF and T4P proteins from the distantly related model unicellular cyanobacterium Synechocystis sp. strain PCC6803 interact in a similar manner to their N. punctiforme counterparts, it is likely that this represents a ubiquitous means of regulating motility in response to light in cyanobacteria.
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Hewelt-Belka, Weronika, Ágata Kot-Wasik, Paula Tamagnini e Paulo Oliveira. "Untargeted Lipidomics Analysis of the Cyanobacterium Synechocystis sp. PCC 6803: Lipid Composition Variation in Response to Alternative Cultivation Setups and to Gene Deletion". International Journal of Molecular Sciences 21, n. 23 (24 novembre 2020): 8883. http://dx.doi.org/10.3390/ijms21238883.
Testo completoAbstract (sommario):
Cyanobacteria play an important role in several ecological environments, and they are widely accepted to be the ancestors of chloroplasts in modern plants and green algae. Cyanobacteria have become attractive models for metabolic engineering, with the goal of exploring them as microbial cell factories. However, the study of cyanobacterial lipids’ composition and variation, and the assessment of the lipids’ functional and structural roles have been largely overlooked. Here, we aimed at expanding the cyanobacterial lipidomic analytical pipeline by using an untargeted lipidomics approach. Thus, the lipid composition variation of the model cyanobacterium Synechocystis sp. PCC 6803 was investigated in response to both alternative cultivation setups and gene deletion. This approach allowed for detecting differences in total lipid content, alterations in fatty-acid unsaturation level, and adjustments of specific lipid species among the identified lipid classes. The employed method also revealed that the cultivation setup tested in this work induced a deeper alteration of the cyanobacterial cell lipidome than the deletion of a gene that results in a dramatic increase in the release of lipid-rich outer membrane vesicles. This study further highlights how growth conditions must be carefully selected when cyanobacteria are to be engineered and/or scaled-up for lipid or fatty acids production.
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Asih, D. R., T. C. Summerfield e J. J. Eaton-Rye. "Exploration of cyanobacteria as bioremediation candidates to reduce phosphorus contamination". IOP Conference Series: Earth and Environmental Science 1062, n. 1 (1 luglio 2022): 012027. http://dx.doi.org/10.1088/1755-1315/1062/1/012027.
Testo completoAbstract (sommario):
Abstract The aim of this research is to evaluate cyanobacteria as a bioremediation agent for the removal of inorganic phosphate. We have adopted two approaches. The first approach involves the inactivation of the sphU gene in a model cyanobacterium. This gene encodes a negative regulator of the pho-regulon, this regulon includes genes involved in phosphate uptake. Inactivation of sphU results in the constitutive uptake of inorganic phosphate and its accumulation in polyphosphate bodies within cyanobacterial cells. Preliminary data using Synechocystis sp. PCC 6803 has shown that the ΔSphU strain removed 96% of phosphate from the growth medium in 36 h whereas a similar phosphate depletion by wild-type cells took ~72 h. Our second approach involves the screening of native cyanobacteria to identify strains that have optimised their ability to take up phosphate. Our goal is to evaluate suitable cyanobacteria for phosphate uptake. This will be achieved through mesocosm studies designed to assess the ability of the cyanobacteria to selectively remove phosphate with the accompanying generation of biomass with potential to be used as feedstock for various biotechnological applications.
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Toledo, Gerardo, Yoav Bashan e Al Soeldner. "In vitro colonization and increase in nitrogen fixation of seedling roots of black mangrove inoculated by a filamentous cyanobacteria". Canadian Journal of Microbiology 41, n. 11 (1 novembre 1995): 1012–20. http://dx.doi.org/10.1139/m95-140.
Testo completoAbstract (sommario):
An isolate of the filamentous cyanobacterium Microcoleus sp. was obtained from black mangrove aerial root (pneumatophore) and inoculated onto young mangrove seedlings to evaluate N2-fixation and root-colonization capacities of the bacterium under in vitro conditions in closed-system experiments. N2 fixation (acetylene reduction) gradually increased with time and reached its peak 5 days after inoculation. Later, it decreased sharply. The level of N2 fixation in the presence of the plant was significantly higher than the amount of nitrogen fixed by a similar quantity of cyanobacteria on a N-free growth medium. The main feature of this root colonization was the gradual production of a biofilm in which the cyanobacterial filaments were embedded. Visible biofilm production increased with time until it completely covered the entire root system of the plant. The in-and-out movement of cyanobacterial filaments from the biofilm probably allows colonization of uncolonized portions of the root several days after the initial inoculation. This is, to the best of our knowledge, the first report of the artificial inoculation of cyanobacteria on marine mangroves.Key words: Avicennia germinans, beneficial bacteria, biofilm, black mangrove, diazotrophic cyanobacteria, Microcoleus sp., nitrogen fixation, plant growth-promoting bacteria, root colonization.
24
Cairns, Johannes, Sebastián Coloma, Kaarina Sivonen e Teppo Hiltunen. "Evolving interactions between diazotrophic cyanobacterium and phage mediate nitrogen release and host competitive ability". Royal Society Open Science 3, n. 12 (dicembre 2016): 160839. http://dx.doi.org/10.1098/rsos.160839.
Testo completoAbstract (sommario):
Interactions between nitrogen-fixing (i.e. diazotrophic) cyanobacteria and their viruses, cyanophages, can have large-scale ecosystem effects. These effects are mediated by temporal alterations in nutrient availability in aquatic systems owing to the release of nitrogen and carbon sources from cells lysed by phages, as well as by ecologically important changes in the diversity and fitness of cyanobacterial populations that evolve in the presence of phages. However, ecological and evolutionary feedbacks between phages and nitrogen-fixing cyanobacteria are still relative poorly understood. Here, we used an experimental evolution approach to test the effect of interactions between a common filamentous, nitrogen-fixing cyanobacterium ( Nodularia sp.) and its phage on cellular nitrogen release and host properties. Ecological, community-level effects of phage-mediated nitrogen release were tested with a phytoplankton bioassay. We found that cyanobacterial nitrogen release increased significantly as a result of viral lysis, which was associated with enhanced growth of phytoplankton species in cell-free filtrates compared with phage-resistant host controls in which lysis and subsequent nutrient release did not occur after phage exposure. We also observed an ecologically important change among phage-evolved cyanobacteria with phage-resistant phenotypes, a short-filamentous morphotype with reduced buoyancy compared with the ancestral long-filamentous morphotype. Reduced buoyancy might decrease the ability of these morphotypes to compete for light compared with longer, more buoyant filaments. Together, these findings demonstrate the potential of cyanobacteria–phage interactions to affect ecosystem biogeochemical cycles and planktonic community dynamics.
25
Wilk-Woźniak, Elżbieta. "An introduction to the 'micronet' of cyanobacterial harmful algal blooms (CyanoHABs): cyanobacteria, zooplankton and microorganisms: a review". Marine and Freshwater Research 71, n. 5 (2020): 636. http://dx.doi.org/10.1071/mf18378.
Testo completoAbstract (sommario):
Cyanobacterial harmful algal blooms are known all around the world. Climate change (temperature increase) and human activity (eutrophication) are factors that promote the proliferation of cyanobacteria, leading to the development of blooms and the release of toxins. Abiotic and biotic factors are responsible for the development of blooms and how long they last. Although the abiotic factors controlling blooms are well known, knowledge of biotic factors and their interactions is still lacking. This paper reviews five levels of biotic interactions, namely cyanobacteria–zooplankton, cyanobacteria–ciliates, cyanobacteria–bacteria, cyanobacteria–viruses and cyanobacteria–fungi, showing a more complex food web network than was previously thought. New findings published recently, such as the relationships between cyanobacteria and viruses or cyanobacteria and fungi, indicate that cyanobacterial blooms are not the end of the cycle of events taking place in water habitats, but rather the middle of them. As such, a new approach needs to consider mutual connections, genetic response, horizontal gene transfer and non-linear flow of carbon.
26
Andeden, Enver Ersoy, Sahlan Ozturk e Belma Aslim. "Antiproliferative, neurotoxic, genotoxic and mutagenic effects of toxic cyanobacterial extracts". Interdisciplinary Toxicology 11, n. 4 (1 dicembre 2018): 267–74. http://dx.doi.org/10.2478/intox-2018-0026.
Testo completoAbstract (sommario):
Abstract Cyanobacteria are the rich resource of various secondary metabolites including toxins with broad pharmaceutical significance. The aim of this work was to evaluate the antiproliferative, neurotoxic, genotoxic and mutagenic effects of cyanobacterial extracts containing Microcystin-LR (MCLR) in vitro. ELISA analysis results showed that MCLR contents of five cyanobacterial extracts were 2.07 ng/mL, 1.43 ng/mL, 1.41 ng/mL, 1.27 ng/mL, and 1.12 ng/mL for Leptolyngbya sp. SB1, Phormidium sp. SB4, Oscillatoria earlei SB5, Phormidium sp. SB2, Uncultured cyanobacterium, respectively. Phormidium sp. SB4 and Phormidium sp. SB2 extracts had the lowest neurotoxicity (86% and 79% cell viability, respectively) and Oscillatoria earlei SB5 extracts had the highest neurotoxicity (47% cell viability) on PC12 cell at 1000 µg/ml extract concentration. Leptolyngbya sp. SB1 and Phormidium sp. SB2 showed the highest antiproliferative effect (92% and 77% cell death) on HT29 cell. On the other hand, all concentrations of five toxic cyanobacterial extracts induced DNA damage between 3.0% and 1.3% of tail intensity and did not cause any direct mutagenic effect at the 1000 µg/plate cyanobacterial extracts. These results suggest that cyanobacteria-derived MCLR is a promising candidate for development of effective agents against colon cancer.
27
Singh, Venus, e DV Singh. "Cyanobacteria modulated changes and its impact on bioremediation of saline-alkaline soils". Bangladesh Journal of Botany 44, n. 4 (21 ottobre 2018): 653–58. http://dx.doi.org/10.3329/bjb.v44i4.38646.
Testo completoAbstract (sommario):
Saline-alkaline (Usar) soils have high pH and undesirable salts on their surface. A halotolerant, heterocystous and nitrogen fixing cyanobacterium Nostoc calcicola Breb. BREB grow successfully on salinealkaline soils of Eastern Uttar Pradesh. Soil pot experimentation has been conducted in laboratory condition to study the reclamation of saline-alkaline soils collected from investigated site. Both sterilized and natural soils were taken in earthen pots to observe the changes in soil properties inoculated with cyanobacteria and gypsum. In such treated soils significant decrease in pH, ECe and Na+ have been observed with cyanobacterial application. There also occurs a significant increase in organic carbon. Experimental reclamation of such soils has been found with cyanobacteria with or without gypsum. N. calcicola + gypsum seem to be a suitable combination for reclamation of saline-alkaline soils. This study highlights that a biological amendment with halotolerant cyanobacteria and gypsum in combination shows better option for bioremediation of saline-alkaline (Usar soils).
28
Kapitulčinova, D., C. S. Cockell, K. R. Hallam e K. V. Ragnarsdottir. "Effect of cyanobacterial growth on biotite surfaces under laboratory nutrient-limited conditions". Mineralogical Magazine 72, n. 1 (febbraio 2008): 71–75. http://dx.doi.org/10.1180/minmag.2008.072.1.71.
Testo completoAbstract (sommario):
AbstractLaboratory experiments with two cyanobacterial strains grown on low-nutrient agar media in the presence of biotite flakes were performed in order to reveal possible mechanisms and rates of cyanobacterial bioweathering. Both cyanobacteria colonized the biotite flakes.Leptolyngbyagrew mostly in the biotite interlayers, whereasHassalliacolonized the sides and the topmost surface of the biotite flakes. After a 3-month incubation, rounded features including cyanobacterium-shaped pits were observed on the biotite surface cleared of the organic material. No such features were observed on flakes incubated for 1 month.
29
Apdila, Egi Tritya, Shukumi Inoue, Mie Shimojima e Koichiro Awai. "Complete Replacement of the Galactolipid Biosynthesis Pathway with a Plant-Type Pathway in the Cyanobacterium Synechococcus elongatus PCC 7942". Plant and Cell Physiology 61, n. 9 (9 luglio 2020): 1661–68. http://dx.doi.org/10.1093/pcp/pcaa090.
Testo completoAbstract (sommario):
Abstract Monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the major components of thylakoid membranes and well-conserved from cyanobacteria to chloroplasts. However, cyanobacteria and chloroplasts synthesize these galactolipids using different pathways and enzymes, but they are believed to share a common ancestor. This fact implies that there was a replacement of the cyanobacterial galactolipid biosynthesis pathway during the evolution of a chloroplast. In this study, we first replaced the cyanobacterial MGDG biosynthesis pathway in a model cyanobacterium, Synechococcus elongatus PCC 7942, with the corresponding plant-type pathway. No obvious phenotype was observed under the optimum growth condition, and the content of membrane lipids was not largely altered in the transformants. We next replaced the cyanobacterial DGDG biosynthesis pathway with the corresponding plant-type pathway using the strain described above and isolated the strain harboring the replaced plant-type pathway instead of the whole galactolipid biosynthesis pathway. This transformant, SeGPT, can grow photoautotrophically, indicating that cyanobacterial galactolipid biosynthesis pathways can be functionally complemented by the corresponding plant-type pathways and that the lipid products MGDG and DGDG, and not biosynthesis pathways, are important. While SeGPT does not show strong growth retardation, the strain has low cellular chlorophyll content but it retained a similar oxygen evolution rate per chlorophyll content compared with the wild type. An increase in total membrane lipid content was observed in SeGPT, which was caused by a significant increase in DGDG content. SeGPT accumulated carotenoids from the xanthophyll groups. These results suggest that cyanobacteria have the capacity to accept other pathways to synthesize essential components of thylakoid membranes.
30
Wilson, Kim M., Mark A. Schembri, Peter D. Baker e Christopher P. Saint. "Molecular Characterization of the Toxic Cyanobacterium Cylindrospermopsis raciborskii and Design of a Species-Specific PCR". Applied and Environmental Microbiology 66, n. 1 (1 gennaio 2000): 332–38. http://dx.doi.org/10.1128/aem.66.1.332-338.2000.
Testo completoAbstract (sommario):
ABSTRACT Cylindrospermopsis raciborskii is a toxic-bloom-forming cyanobacterium that is commonly found in tropical to subtropical climatic regions worldwide, but it is also recognized as a common component of cyanobacterial communities in temperate climates. Genetic profiles of C. raciborskii were examined in 19 cultured isolates originating from geographically diverse regions of Australia and represented by two distinct morphotypes. A 609-bp region of rpoC1, a DNA-dependent RNA polymerase gene, was amplified by PCR from these isolates with cyanobacterium-specific primers. Sequence analysis revealed that all isolates belonged to the same species, including morphotypes with straight or coiled trichomes. Additional rpoC1 gene sequences obtained for a range of cyanobacteria highlighted clustering of C. raciborskii with other heterocyst-producing cyanobacteria (orders Nostocales andStigonematales). In contrast, randomly amplified polymorphic DNA and short tandemly repeated repetitive sequence profiles revealed a greater level of genetic heterogeneity amongC. raciborskii isolates than did rpoC1 gene analysis, and unique band profiles were also found among each of the cyanobacterial genera examined. A PCR test targeting a region of therpoC1 gene unique to C. raciborskii was developed for the specific identification of C. raciborskiifrom both purified genomic DNA and environmental samples. The PCR was evaluated with a number of cyanobacterial isolates, but a PCR-positive result was only achieved with C. raciborskii. This method provides an accurate alternative to traditional morphological identification of C. raciborskii.
31
Kelly, Ciarán L., George M. Taylor, Aistė Šatkutė, Linda Dekker e John T. Heap. "Transcriptional Terminators Allow Leak-Free Chromosomal Integration of Genetic Constructs in Cyanobacteria". Microorganisms 7, n. 8 (16 agosto 2019): 263. http://dx.doi.org/10.3390/microorganisms7080263.
Testo completoAbstract (sommario):
Cyanobacteria are promising candidates for sustainable bioproduction of chemicals from sunlight and carbon dioxide. However, the genetics and metabolism of cyanobacteria are less well understood than those of model heterotrophic organisms, and the suite of well-characterised cyanobacterial genetic tools and parts is less mature and complete. Transcriptional terminators use specific RNA structures to halt transcription and are routinely used in both natural and recombinant contexts to achieve independent control of gene expression and to ‘insulate’ genes and operons from one another. Insulating gene expression can be particularly important when heterologous or synthetic genetic constructs are inserted at genomic locations where transcriptional read-through from chromosomal promoters occurs, resulting in poor control of expression of the introduced genes. To date, few terminators have been described and characterised in cyanobacteria. In this work, nineteen heterologous, synthetic or putative native Rho-independent (intrinsic) terminators were tested in the model freshwater cyanobacterium, Synechocystis sp. PCC 6803, from which eleven strong terminators were identified. A subset of these strong terminators was then used to successfully insulate a chromosomally–integrated, rhamnose-inducible rhaBAD expression system from hypothesised ‘read-through’ from a neighbouring chromosomal promoter, resulting in greatly improved inducible control. The addition of validated strong terminators to the cyanobacterial toolkit will allow improved independent control of introduced genes.
32
Álvarez, Consolación, José A. Navarro, Fernando P. Molina-Heredia e Vicente Mariscal. "Endophytic Colonization of Rice (Oryza sativa L.) by the Symbiotic Strain Nostoc punctiforme PCC 73102". Molecular Plant-Microbe Interactions® 33, n. 8 (agosto 2020): 1040–45. http://dx.doi.org/10.1094/mpmi-01-20-0015-sc.
Testo completoAbstract (sommario):
Cyanobacteria are phototrophic microorganisms able to establish nitrogen-fixing symbiotic associations with representatives of all four of the major phylogenetic divisions of terrestrial plants. Despite increasing knowledge on the beneficial effects of cyanobacteria in rice fields, the information about the interaction between these microorganisms and rice at the molecular and structural levels is still limited. We have used the model nitrogen-fixing cyanobacterium Nostoc punctiforme to promote a long-term stable endophytic association with rice. Inoculation with this strain of hydroponic cultures of rice produces a fast adherence of the cyanobacterium to rice roots. At longer times, cyanobacterial growth in the proximity of the roots increased until reaching a plateau. This latter phase coincides with the intracellular colonization of the root epidermis and exodermis. Structural analysis of the roots revealed that the cyanobacterium use an apoplastic route to colonize the plant cells. Moreover, plant roots inoculated with N. punctiforme show both the presence of heterocysts and nitrogenase activity, resulting in the promotion of plant growth under nitrogen deficiency, thus providing benefits for the plant.
33
Duchnik, Kornelia, Jan Bialczyk, Ewelina Chrapusta-Srebrny e Beata Bober. "Inhibition of growth rate and cylindrospermopsin synthesis by Raphidiopsis raciborskii upon exposure to macrophyte Lemna trisulca (L)". Ecotoxicology 30, n. 3 (12 marzo 2021): 470–77. http://dx.doi.org/10.1007/s10646-021-02377-7.
Testo completoAbstract (sommario):
AbstractImpact of macrophyte Lemna trisulca on the growth rate and synthesis of cylindrospermopsin (CYN) by cyanobacterium Raphidiopsis raciborskii was determined. The presence of L. trisulca inhibited the biomass accumulation of the cyanobacterium by 25% compared to the control during co-cultivation. The simultaneous cultivation of these organisms slightly affected the inhibition of macrophyte growth rate by 5.5% compared to the control. However, no morphological changes of L. trisulca after incubation with cyanobacteria were observed. It was also shown that the long-term (35 days) co-cultivation of R. raciborskii and L. trisulca led to a decrease in CYN concentration in media and cyanobacterial cells by 32 and 38%, respectively, compared to the values obtained for independent cultivation of cyanobacterium. Excessive absorption of phosphate ions by L. trisulca from the medium compared to nitrate ions led to a significant increase in the nitrate:phosphate ratio in the media, which inhibits the development of cyanobacterium. The obtained results indicate that L. trisulca in the natural environment may affect the physiology of cyanobacteria. The presented study is the first assessment of the allelopathic interaction of macrophyte and R. raciborskii.
34
Joshi, Susan M., e Leland J. Jackson. "How Might Changing Climate Limit Cyanobacteria Growth in Shallow Prairie Lakes? An Empirical Space-For-Time Evaluation of the Potential Role of Increasing Sulfate". Advances in Environmental and Engineering Research 3, n. 1 (20 novembre 2021): 1. http://dx.doi.org/10.21926/aeer.2201007.
Testo completoAbstract (sommario):
Cyanobacteria blooms alter aquatic ecosystems and occur frequently in shallow prairie lakes, which are predicted to increase in salinity as the regional climate becomes hotter and drier. However, flat landscapes that experience depression bottom salinity with high concentrations of sulfate in addition to sodium and chloride, may mitigate nutrient increases or even inhibit cyanobacteria growth. Cyanobacteria can dominate shallow lakes with low N:P ratios because many cyanobacteria species fix dissolved N2, whether due to in-lake denitrification or exchange with the atmosphere, a process that requires molybdenum as an enzyme cofactor. Sulfate can compete with molybdate at cellular uptake sites, potentially limiting the competitive advantage of cyanobacteria. We studied 25 lakes located in a relatively limited geographic region of southern Alberta (Canada) and used a space-for-time analysis to model scenarios of increased sulfate concentrations under changing climate. Monthly, we measured nitrogen, phosphorus, sulfate, molybdenum, and cyanobacterial pigments and used mixed effects models to identify empirical relationships. Sulfate drives conductivity in the region and we found that most saline lakes we sampled are turbid lakes with high nutrients and high cyanobacteria biomass. In addition to phosphorus, molybdenum predicted cyanobacterial pigments in the top two models, showing a positive relationship with cyanobacterial biomass. We also found a negative relationship between sulfate concentration and cyanobacteria pigments, which suggests that as lakes get saltier, even with increased nutrients, there may not be an incremental increase in cyanobacteria biomass. Our results therefore suggest that competition between sulfate and molybdate may limit future cyanobacteria growth in shallow lakes and that with a warmer and drier climate it may not be inevitable that shallow lakes will continue to be dominated by cyanobacterial blooms, a hypothesis that could be tested directly via experimentation.
35
Wang, Mengmeng, Huifen Zhang, Menggaoshan Chen, Liuyan Yang e Yichen Yang. "Dark accelerates dissolved inorganic phosphorus release of high-density cyanobacteria". PLOS ONE 15, n. 12 (22 dicembre 2020): e0243582. http://dx.doi.org/10.1371/journal.pone.0243582.
Testo completoAbstract (sommario):
Bloom-forming cyanobacteria dramatically influence nutrient cycling in eutrophic freshwater lakes. The phosphorus (P) assimilation and release of bloom-forming cyanobacteria significantly may also affect the phosphorus source and amounts in water. To understand the phosphorus release process of bloom-forming cyanobacteria below the accumulated surface and sedimentary bloom-forming cyanobacteria, the degradation of bloom-forming cyanobacteria dominated by Microcystis spp. at different cell density in the dark was investigated over a 25-day microcosm experiment. The dissolved inorganic phosphorus (DIP) and dissolved total phosphorus (DTP) contents increased with the increment of cyanobacterial density, and the dark status markedly increased the proportion of DIP in water during the decline period of bloom-forming cyanobacteria. Meanwhile, the process of cyanobacterial apoptosis accompanied by the changes of malondialdehyde (MDA) and phosphatase (AKP) contents, and the increases of superoxide dismutase (SOD) and catalase (CAT) activities of cyanobacteria in the dark, especially in low-density groups (5.23×108 cells L-1), which further affect the physicochemical water parameters. Moreover, the DIP release from high-density cyanobacteria (7.86×107 cells L-1~5.23×108 cells L-1) resulted from the relative abundance of organophosphorus degrading bacteria in the dark. Therefore, the fast decay of cyanobacteria in the dark could accelerate DIP release, the high DIP release amount from accumulated bloom-cyanobacteria provide adequate P quickly for the sustained growth of cyanobacteria.
36
Hao, Fei, Xinyi Li, Jiameng Wang, Ruoyue Li, Liyan Zou, Kai Wang, Fuqing Chen et al. "Separation of Bioproducts through the Integration of Cyanobacterial Metabolism and Membrane Filtration: Facilitating Cyanobacteria’s Industrial Application". Membranes 12, n. 10 (30 settembre 2022): 963. http://dx.doi.org/10.3390/membranes12100963.
Testo completoAbstract (sommario):
In this work, we propose the development of an efficient, economical, automated, and sustainable method for separating bioproducts from culture medium via the integration of a sucrose-secreting cyanobacteria production process and pressure-driven membrane filtration technology. Firstly, we constructed sucrose-secreting cyanobacteria with a sucrose yield of 600__700 mg/L sucrose after 7 days of salt stress, and the produced sucrose could be fully separated from the cyanobacteria cultures through an efficient and automated membrane filtration process. To determine whether this new method is also economical and sustainable, the relationship between membrane species, operating pressure, and the growth status of four cyanobacterial species was systematically investigated. The results revealed that all four cyanobacterial species could continue to grow after UF filtration. The field emission scanning electron microscopy and confocal laser scanning microscopy results indicate that the cyanobacteria did not cause severe destruction to the membrane surface structure. The good cell viability and intact membrane surface observed after filtration indicated that this innovative cyanobacteria–membrane system is economical and sustainable. This work pioneered the use of membrane separation to achieve the in situ separation of cyanobacterial culture and target products, laying the foundation for the industrialization of cyanobacterial bioproducts.
37
Tsyrenova, D. D., S. V. Zaitseva, O. P. Dagurova, V. B. Dambaev e D. D. Barkhutova. "Cyanobacteria in freshwater Lake Dikoye (Pribaikalsky district, Buryatia, Siberia) under intensive eutrophication". IOP Conference Series: Earth and Environmental Science 908, n. 1 (1 novembre 2021): 012009. http://dx.doi.org/10.1088/1755-1315/908/1/012009.
Testo completoAbstract (sommario):
Abstract We studied freshwater Lake Dikoye located in the coastal zone of Lake Baikal. Negative changes associated with cyanobacterial bloom were observed in the lake. Phototrophs were represented by cyanobacteria, green algae, and diatoms. In the microbial community, Cyanobacteria were the dominant phylum and accounted for up to 48% of the total diversity. Cyanobacteria were represented by 7 genera and 9 species. Microcystis aeruginosa, a potentially toxic species, was dominant among cyanobacteria. According to chlorophyll a content, the lake should be assigned to eutrophic ones. The bacterial eutrophication index for the lake studied varied from 1.17 (middle eutrophic) to 28.2 (hypereutrophic) during cyanobacterial bloom.
38
Barney, Rachael E., Guohong Huang, Torrey L. Gallagher, Maeve Tischbein, John DeWitt, Rachel Martindale, Ethan M. P. LaRochelle, Gregory J. Tsongalis e Elijah W. Stommel. "Validation of a Droplet Digital PCR (ddPCR) Assay to Detect Cyanobacterial 16S rDNA in Human Lung Tissue". Toxics 11, n. 6 (14 giugno 2023): 531. http://dx.doi.org/10.3390/toxics11060531.
Testo completoAbstract (sommario):
Cyanobacteria produce a variety of secondary metabolites, including toxins that may contribute to the development of disease. Previous work was able to detect the presence of a cyanobacterial marker in human nasal and broncoalveolar lavage samples; however, it was not able to determine the quantification of the marker. To further research the relationship between cyanobacteria and human health, we validated a droplet digital polymerase chain reaction (ddPCR) assay to simultaneously detect the cyanobacterial 16S marker and a human housekeeping gene in human lung tissue samples. The ability to detect cyanobacteria in human samples will allow further research into the role cyanobacteria plays in human health and disease.
39
Jalili, Farhad, Saber Moradinejad, Arash Zamyadi, Sarah Dorner, Sébastien Sauvé e Michèle Prévost. "Evidence-Based Framework to Manage Cyanobacteria and Cyanotoxins in Water and Sludge from Drinking Water Treatment Plants". Toxins 14, n. 6 (15 giugno 2022): 410. http://dx.doi.org/10.3390/toxins14060410.
Testo completoAbstract (sommario):
Freshwater bodies and, consequently, drinking water treatment plants (DWTPs) sources are increasingly facing toxic cyanobacterial blooms. Even though conventional treatment processes including coagulation, flocculation, sedimentation, and filtration can control cyanobacteria and cell-bound cyanotoxins, these processes may encounter challenges such as inefficient removal of dissolved metabolites and cyanobacterial cell breakthrough. Furthermore, conventional treatment processes may lead to the accumulation of cyanobacteria cells and cyanotoxins in sludge. Pre-oxidation can enhance coagulation efficiency as it provides the first barrier against cyanobacteria and cyanotoxins and it decreases cell accumulation in DWTP sludge. This critical review aims to: (i) evaluate the state of the science of cyanobacteria and cyanotoxin management throughout DWTPs, as well as their associated sludge, and (ii) develop a decision framework to manage cyanobacteria and cyanotoxins in DWTPs and sludge. The review identified that lab-cultured-based pre-oxidation studies may not represent the real bloom pre-oxidation efficacy. Moreover, the application of a common exposure unit CT (residual concentration × contact time) provides a proper understanding of cyanobacteria pre-oxidation efficiency. Recently, reported challenges on cyanobacterial survival and growth in sludge alongside the cell lysis and cyanotoxin release raised health and technical concerns with regards to sludge storage and sludge supernatant recycling to the head of DWTPs. According to the review, oxidation has not been identified as a feasible option to handle cyanobacterial-laden sludge due to low cell and cyanotoxin removal efficacy. Based on the reviewed literature, a decision framework is proposed to manage cyanobacteria and cyanotoxins and their associated sludge in DWTPs.
40
Liu, Li, An Xiang, Yue Feng, Da Qiao Wei, Heng Yang e Xue Shan Xia. "Cyanobacteria Diversity in Eutrophic Lake of Yunnan, China". Advanced Materials Research 343-344 (settembre 2011): 914–19. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.914.
Testo completoAbstract (sommario):
Cyanobacteria are widespread in eutrophic freshwater lakes and can produce potent toxins which pose serious risk for human and animal health, aquatic ecosystem sustainability and economic vitality. There are 9 major lakes, which eutrophication and related ecological problem had occurred in most of these lakes in Yunnan, China. In this study, water samples were collected at different sampling time from five freshwater plateau lakes, which located in the middle area of Yunnan province, to assess the cyanobacteria diversity vary with the seasons. The morphological character of cyanobacteria were observed by light microscope (LM), the genetic diversity of cyanobacteria had been demonstrated by constructed phylogenetic trees based on DNA sequence of cyanobacteria 16S-23S rRNA internal space (ITS).The results showed that a variety of cyanobacterial species were distributed in five plateau freshwater lakes. The cyanobacterial population consisted mainly of several Microcystis species as dominants in Dianchi Lake and the dominant species of cyanobacteria found in June to October of 2009 was Microcystis aeruginosa. The diversity of cyanobacteria in Caohai was higher than that of Waihai in Dianchi Lake.
41
Bothe, Hermann, Oliver Schmitz, M. Geoffrey Yates e William E. Newton. "Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria". Microbiology and Molecular Biology Reviews 74, n. 4 (dicembre 2010): 529–51. http://dx.doi.org/10.1128/mmbr.00033-10.
Testo completoAbstract (sommario):
SUMMARY This review summarizes recent aspects of (di)nitrogen fixation and (di)hydrogen metabolism, with emphasis on cyanobacteria. These organisms possess several types of the enzyme complexes catalyzing N2 fixation and/or H2 formation or oxidation, namely, two Mo nitrogenases, a V nitrogenase, and two hydrogenases. The two cyanobacterial Ni hydrogenases are differentiated as either uptake or bidirectional hydrogenases. The different forms of both the nitrogenases and hydrogenases are encoded by different sets of genes, and their organization on the chromosome can vary from one cyanobacterium to another. Factors regulating the expression of these genes are emerging from recent studies. New ideas on the potential physiological and ecological roles of nitrogenases and hydrogenases are presented. There is a renewed interest in exploiting cyanobacteria in solar energy conversion programs to generate H2 as a source of combustible energy. To enhance the rates of H2 production, the emphasis perhaps needs not to be on more efficient hydrogenases and nitrogenases or on the transfer of foreign enzymes into cyanobacteria. A likely better strategy is to exploit the use of radiant solar energy by the photosynthetic electron transport system to enhance the rates of H2 formation and so improve the chances of utilizing cyanobacteria as a source for the generation of clean energy.
42
Sharipova, M. Yu, e I. Е. Dubovik. "Cyanobacteria and Algae in the Karlamanskaya Cave (Bashkortostan Republic, Russia)". Theoretical and Applied Ecology, n. 1 (25 marzo 2024): 184–90. http://dx.doi.org/10.25750/1995-4301-2024-1-184-190.
Testo completoAbstract (sommario):
The article presents data on the composition and structure of cyanobacterial-algal cenoses of various habitats of the Karlamanskaya Cave. The study identified 46 species and intraspecific taxa of cyanobacteria and algae belonging to 5 divisions (Cyanobacteria – 17 species and intraspecific taxa, Bacillariophyta – 12 species and intraspecific taxa, Chlorophyta – 14 species, Charophyta – 1 species, Ochrophyta – 2 species), 7 classes, 16 order, 28 families and 36 genera. Leptolyngbya boryana (Gom.) Anagn. et Kom., Oscillatoria rupicola (Hansgirg) Hansgirg ex Forti, Luticola mutica (Kütz.) Mann, Mychonastes homosphaera (Skuja) Kalina et Punс., Chlorella vulgaris Beijerink present the dominant complex of cyanobacteria and algae in all studied habitats. Cyanobacteria dominate in all biotopes of the cave except aquatic ones where diatoms predominated. The maximum number of species was found in the soil at the cave entrance and in the soil of the illuminated cave zone: 31 and 29 species respectively. The lowest number was found in the soil and on the walls (16 and 11 species respectively). Ecological analysis of cyanobacterium and algae revealed 12 life forms: Сh9B9P5X5CF5hydr4amph2PF1NF1C1M1H1. Most of the life forms were found in the illuminated cave zone: in the soil (10 forms), on the wall (10 forms) and at the cave entrance (11 forms). The ecobiomorphs composition of the dark zone is the poorest (5 forms).
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Swartzendruber, Julie A., Rosalinda Monroy Del Toro, Ryan Incrocci, Nessa Seangmany, Joshua R. Gurr, Alejandro M. S. Mayer, Philip G. Williams e Michelle Swanson-Mungerson. "Lipopolysaccharide from the Cyanobacterium Geitlerinema sp. Induces Neutrophil Infiltration and Lung Inflammation". Toxins 14, n. 4 (9 aprile 2022): 267. http://dx.doi.org/10.3390/toxins14040267.
Testo completoAbstract (sommario):
Glucocorticoid-resistant asthma, which predominates with neutrophils instead of eosinophils, is an increasing health concern. One potential source for the induction of neutrophil-predominant asthma is aerosolized lipopolysaccharide (LPS). Cyanobacteria have recently caused significant tidal blooms, and aerosolized cyanobacterial LPS has been detected near the cyanobacterial overgrowth. We hypothesized that cyanobacterial LPS contributes to lung inflammation by increasing factors that promote lung inflammation and neutrophil recruitment. To test this hypothesis, c57Bl/6 mice were exposed intranasally to LPS from the cyanobacterium member, Geitlerinema sp., in vivo to assess neutrophil infiltration and the production of pro-inflammatory cytokines and chemokines from the bronchoalveolar fluid by ELISA. Additionally, we exposed the airway epithelial cell line, A549, to Geitlerinema sp. LPS in vitro to confirm that airway epithelial cells were stimulated by this LPS to increase cytokine production and the expression of the adhesion molecule, ICAM-1. Our data demonstrate that Geitlerinema sp. LPS induces lung neutrophil infiltration, the production of pro-inflammatory cytokines such as Interleukin (IL)-6, Tumor necrosis factor-alpha, and Interferongamma as well as the chemokines IL-8 and RANTES. Additionally, we demonstrate that Geitlerinema sp. LPS directly activates airway epithelial cells to produce pro-inflammatory cytokines and the adhesion molecule, Intercellular Adhesion Molecule-1 (ICAM-1), in vitro using the airway epithelial cell line, A549. Based on our findings that use Geitlerinema sp. LPS as a model system, the data indicate that cyanobacteria LPS may contribute to the development of glucocorticoid-resistant asthma seen near water sources that contain high levels of cyanobacteria.
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Puyana, Mónica, Julián Alberto Prato, Christian Felipe Nieto, Freddy Alejandro Ramos, Leonardo Castellanos, Paola Pinzón e Juan Camilo Zárate. "Experimental Approaches for the Evaluation of Allelopathic Interactions Between Hermatypic Corals and Marine Benthic Cyanobacteria in the Colombian Caribbean". Acta Biológica Colombiana 24, n. 2 (1 maggio 2019): 243–54. http://dx.doi.org/10.15446/abc.v24n2.72706.
Testo completoAbstract (sommario):
Blooms of marine benthic cyanobacteria are recurrent in several locations at the Colombian Caribbean. In these events, cyanobacteria grow over the substrate and benthic organisms although their effect has not been fully assessed. This study evaluated interactions between cyanobacteria and hermatypic corals, in order to identify any deleterious effects that could be related to allelopathic mechanisms. Organic extracts from cyanobacteria collected in San Andres, Old Providence and Rosario islands were tested against embryos of the reef-building coral Orbicella annularis. The indirect effect of cyanobacterial extracts was also assessed by resuspending the extracts in seawater and monitoring polyp retraction and recovery of the coral Madracis mirabilis (=auretenra). Additionally, the effect of direct contact between cyanobacterial extracts and the coral Porites porites was assessed by incorporating cyanobacterial extracts into PhytagelTM gels and placed in direct contact with the coral. After 24, 48 and 72 h of exposure, chromatographic profiles of associated zooxanthellae was evaluated by HPLC. A deleterious effect on the zooxanthellae was evidenced by an increase in pheophytin, a degradation product from chlorophyll. The competitive abilities of algae and cyanobacteria should be considered as a constraint to reef restoration initiatives. Cyanobacteria have the ability to compete with corals due to their growth rates, defenses against herbivory and potentially allelopathic mechanisms.
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Zhao, C. S., X. Pan, S. T. Yang, X. L. Wang, X. J. Liu, Y. Sun, Y. Yang e T. L. Pan. "Drivers of cyanobacterial blooms in lakes and reservoirs in Jinan City, China". Marine and Freshwater Research 71, n. 5 (2020): 626. http://dx.doi.org/10.1071/mf18376.
Testo completoAbstract (sommario):
Cyanobacterial blooms are a serious issue and frequently occur in lakes and reservoirs. Understanding how topography and human activities affect cyanobacterial dominance and blooms can greatly enhance the success of restoration projects to reduce blooms. Therefore, in this study the dominant species of cyanobacteria were determined by calculating the break point of the cumulative dominance curve for multiple sites in Jinan, China. In addition, the key drivers affecting the dominant cyanobacteria species were identified by canonical correspondence analysis and correlations between topography, human activities and the key drivers of the dominant cyanobacteria were investigated using random forests analysis. Merismopedia glauca, Merismopedia tenuissima, Microcystis aeruginosa, Oscillatoria tenuis, Phormidium tenus and Raphidiopsis sinensia were determined to be the dominant species. The key drivers of cyanobacterial bloom development were total phosphorus (TP), ammonium nitrogen (NH3-N), water temperature and total hardness. Topography and human activities were highly correlated with the key driving factors. The higher the altitude, the greater the effect of water temperature on the cyanobacteria community. In the area where sewage irrigation was present and a large amount of chemical fertiliser was used, total hardness had a greater effect on the cyanobacteria community. In areas where the population was more concentrated, TP and NH3-N had greater effects on the cyanobacteria community.
46
Ehrenreich, Ian M., John B. Waterbury e Eric A. Webb. "Distribution and Diversity of Natural Product Genes in Marine and Freshwater Cyanobacterial Cultures and Genomes". Applied and Environmental Microbiology 71, n. 11 (novembre 2005): 7401–13. http://dx.doi.org/10.1128/aem.71.11.7401-7413.2005.
Testo completoAbstract (sommario):
ABSTRACT Natural products are a functionally diverse class of biochemically synthesized compounds, which include antibiotics, toxins, and siderophores. In this paper, we describe both the detection of natural product activities and the sequence identification of gene fragments from two molecular systems that have previously been implicated in natural product production, i.e., nonribosomal peptide synthetases (NRPSs) and modular polyketide synthases (PKSs), in diverse marine and freshwater cyanobacterial cultures. Using degenerate PCR and the sequencing of cloned products, we show that NRPSs and PKSs are common among the cyanobacteria tested. Our molecular data, when combined with genomic searches of finished and progressing cyanobacterial genomes, demonstrate that not all cyanobacteria contain NRPS and PKS genes and that the filamentous and heterocystous cyanobacteria are the richest sources of these genes and the most likely sources of novel natural products within the phylum. In addition to validating the use of degenerate primers for the identification of PKS and NRPS genes in cyanobacteria, this study also defines numerous gene fragments that will be useful as probes for future studies of the synthesis of natural products in cyanobacteria. Phylogenetic analyses of the cyanobacterial NRPS and PKS fragments sequenced in this study, as well as those from the cyanobacterial genome projects, demonstrate that there is remarkable diversity and likely novelty of these genes within the cyanobacteria. These results underscore the potential variety of novel products being produced by these ubiquitous organisms.
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Dulić, Tamara, Zorica Svirčev, Tamara Palanački Malešević, Elisabeth J. Faassen, Henna Savela, Qingzhen Hao e Jussi Meriluoto. "Assessment of Common Cyanotoxins in Cyanobacteria of Biological Loess Crusts". Toxins 14, n. 3 (16 marzo 2022): 215. http://dx.doi.org/10.3390/toxins14030215.
Testo completoAbstract (sommario):
Cyanotoxins are a diverse group of bioactive compounds produced by cyanobacteria that have adverse effects on human and animal health. While the phenomenon of cyanotoxin production in aquatic environments is well studied, research on cyanotoxins in terrestrial environments, where cyanobacteria abundantly occur in biocrusts, is still in its infancy. Here, we investigated the potential cyanotoxin production in cyanobacteria-dominated biological loess crusts (BLCs) from three different regions (China, Iran, and Serbia) and in cyanobacterial cultures isolated from the BLCs. The presence of cyanotoxins microcystins, cylindrospermopsin, saxitoxins, and β-N-methylamino-L-alanine was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, while the presence of cyanotoxin-encoding genes (mcyE, cyrJ, sxtA, sxtG, sxtS, and anaC) was investigated by polymerase chain reaction (PCR) method. We could not detect any of the targeted cyanotoxins in the biocrusts or the cyanobacterial cultures, nor could we amplify any cyanotoxin-encoding genes in the cyanobacterial strains. The results are discussed in terms of the biological role of cyanotoxins, the application of cyanobacteria in land restoration programs, and the use of cyanotoxins as biosignatures of cyanobacterial populations in loess research. The article highlights the need to extend the field of research on cyanobacteria and cyanotoxin production to terrestrial environments.
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Rigonato, Janaina, Natalia Gonçalves, Ana Paula Dini Andreote, Marcio Rodrigues Lambais e Marli Fátima Fiore. "Estimating genetic structure and diversity of cyanobacterial communities in Atlantic forest phyllosphere". Canadian Journal of Microbiology 62, n. 11 (novembre 2016): 953–60. http://dx.doi.org/10.1139/cjm-2016-0229.
Testo completoAbstract (sommario):
Cyanobacterial communities on the phyllosphere of 4 plant species inhabiting the endangered Brazilian Atlantic Forest biome were evaluated using cultivation-independent molecular approaches. Total genomic DNA was extracted from cells detached from the surface of leaves of Euterpe edulis, Guapira opposita, Garcinia gardneriana, and Merostachys neesii sampled in 2 Brazilian Atlantic Forest locations along an elevational gradient, i.e., lowland and montane forest. The DNA fingerprinting method PCR–DGGE revealed that the cyanobacterial phyllosphere community structures were mainly influenced by the plant species; geographical location of the plant had little effect. The 16S rRNA gene sequences obtained by clone libraries showed a predominance of nitrogen-fixing cyanobacteria of the order Nostocales, even though the majority of retrieved operational taxonomic units (∼60% of the sequences) showed similarity only to uncultured cyanobacteria phylotypes. The leaf surface of Guapira opposita had the highest richness and diversity of cyanobacteria, whereas the M. neesii (bamboo) had the largest number of copies of cyanobacterial 16S rRNA gene per cm2of leaf. This study investigated cyanobacteria diversity and its distribution pattern in Atlantic forest phyllosphere. The results indicated that plant species is the main driver of cyanobacteria community assemblage in the phyllosphere and that these communities are made up of a high diversity of cyanobacterial taxa that need to be discovered.
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Long, Ben M., G. Dean Price e Murray R. Badger. "Proteomic assessment of an established technique for carboxysome enrichment from Synechococcus PCC7942". Canadian Journal of Botany 83, n. 7 (1 luglio 2005): 746–57. http://dx.doi.org/10.1139/b05-058.
Testo completoAbstract (sommario):
Carboxysomes are protein-bound, polyhedral microbodies within cyanobacteria, containing the key enzyme for photosynthetic CO2 fixation, ribulose-1,5-bisphosphate carboxylaseoxygenase (Rubisco). Sequencing of cyanobacterial genomes has revealed that cyanobacteria possess one or other of two types of carboxysomes. Cyanobacteria containing form 1A Rubisco possess α-carboxysomes, while those with form 1B Rubisco possess β-carboxysomes. Given the central importance of carboxysomes in the CO2-concentrating mechanism of cyanobacteria, understanding the nature and composition of these structures is of considerable importance. In an effort to develop techniques for the characterization of the structure of β-carboxysomes, particularly the outer protein shell, we have undertaken a proteomic assessment of the PercollMg2+ carboxysome enrichment technique using the freshwater cyanobacterium Synechococcus sp. PCC7942. Both matrix-assisted laser desorptionionization time of flight mass spectrometry (MALDI-TOF MS) and multidimensional protein identification technology (MuDPIT) methods were used to determine the protein content of a novel carboxysome-rich fraction. A total of 17 proteins were identified using MALDI-TOF MS from enriched carboxysome preparations, while 122 proteins were identified using MuDPIT analysis on the same material. The carboxysomal protein CcmM was identified by MALDI-TOF MS as two distinct proteins of 38 and 58 kDa. The only other carboxysomal proteins identified were the large and small subunits of Rubisco (RbcL and RbcS). Reasons for the lack of evidence for the expected full complement of carboxysomal proteins and future directions are discussed.Key words: CO2-concentrating mechanism, cyanobacteria, carboxysomes, proteomics.
50
Zou, Xiangbo, Xinyu Jiang, Chuangting Chen, Cao Kuang, Ji Ye, Shiwei Qin, Jiong Cheng, Guangli Liu, Faming Wang e Shiqin Yu. "Phosphorus Rather than Nitrogen Addition Changed Soil Cyanobacterial Community in a Tropical Secondary Forest of South China". Forests 14, n. 11 (9 novembre 2023): 2216. http://dx.doi.org/10.3390/f14112216.
Testo completoAbstract (sommario):
Soil cyanobacteria in tropical forests is understudied despite its important role in soil biochemical process and plant growth. Under a nitrogen (N) deposition background in tropical forests, it is important to learn how soil cyanobacterial communities respond to N deposition and whether phosphorus (P) mediated this response. A fully two-factor (N and P additions) factorial design with four blocks (replicates), each including a 12 × 12 m plot per treatment (Control, +N, +P, and +NP) were established in a tropical secondary forest in 2009. In July of 2022, soil cyanobacteria at 0–10 cm and 10–20 cm depths in the experimental site were collected and analyzed using a metagenomic method. The impact of N and P additions on soil cyanobacteria remained consistent across the different soil depths, even though there was a significant contrast between the two layers. The effect of N addition on soil cyanobacteria did not significantly interact with P addition. N addition increased soil N availability and decreased soil pH but did not significantly affect the soil cyanobacterial community. In contrast, P addition increased soil P availability and soil pH, but decreased soil N availability and substantially changed the soil cyanobacterial community. P addition significantly decreased the abundance of soil cyanobacteria, especially abundant ones. P addition also increased cyanobacterial species richness and Shannon’s diversity, which might be explained by the decline in dominant species and the emergence of new species as nestedness and indicator species analyses suggest. We concluded that (1) soil cyanobacteria in tropical forests exhibits a greater sensitivity to elevated P availability compared to N; (2) an increase in soil P supply may mitigate the advantage held by dominant species, thus facilitating the growth of other species and leading to alterations in the soil cyanobacterial community. This study improves our understanding on how soil cyanobacterial communities in tropical forest responds to N and P addition.