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Kaarina Sivonen - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic and morphological evaluation of the genera Anabaena, Aphanizomenon, Trichormus and Nostoc (Nostocales, Cyanobacteria).
International journal of systematic and evolutionary microbiology, 2005Co-Authors: Pirjo Rajaniemi, Anne Rantala, Pavel Hrouzek, Klára Kaštovská, Raphaël Willame, Lucien Hoffmann, Jiří Komárek, Kaarina SivonenAbstract:The heterocytous cyanobacteria form a monophyletic group according to 16S rRNA gene sequence data. Within this group, phylogenetic and morphological studies have shown that genera such as Anabaena and Aphanizomenon are intermixed. Moreover, the phylogeny of the genus Trichormus, which was recently separated from Anabaena, has not been investigated. The aim was to study the taxonomy of the genera Anabaena, Aphanizomenon, Nostoc and Trichormus belonging to the family Nostocaceae (subsection IV.I) by morphological and phylogenetic analyses of 16S rRNA gene, rpoB and rbcLX sequences. New strains were isolated to avoid identification problems caused by morphological changes of strains during cultivation. Morphological and phylogenetic data showed that benthic and planktic Anabaena strains were intermixed. In addition, the present study confirmed that Anabaena and Aphanizomenon strains were not monophyletic, as previously demonstrated. The evolutionary distances between the strains indicated that the planktic Anabaena and Aphanizomenon strains as well as five benthic Anabaena strains in cluster 1 could be assigned to a single genus. On the basis of the 16S rRNA, rpoB and rbcLX gene sequences, the Anabaena/Aphanizomenon strains (cluster 1) were divided into nine supported subclusters which could also be separated morphologically, and which therefore might represent different species. Trichormus strains were morphologically and phylogenetically heterogeneous and did not form a monophyletic cluster. These Trichormus strains, which were representatives of three distinct species, might actually belong to three genera according to the evolutionary distances. Nostoc strains were also heterogeneous and seemed to form a monophyletic cluster, which may contain more than one genus. It was found that certain morphological features were stable and could be used to separate different phylogenetic clusters. For example, the width and the length of akinetes were useful features for classification of the Anabaena/Aphanizomenon strains in cluster 1. This morphological and phylogenetic study with fresh isolates showed that the current classification of these anabaenoid genera needs to be revised.
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cellular fatty acids as chemotaxonomic markers of the genera anabaena aphanizomenon microcystis nostoc and planktothrix cyanobacteria
International Journal of Systematic and Evolutionary Microbiology, 2002Co-Authors: Muriel Gugger, Irmgard Suominen, Jeanfrancois Humbert, Christina Lyra, Irina Tsitko, Mirja Salkinojasalonen, Kaarina SivonenAbstract:The cellular fatty acid content of 22 cyanobacterial strains belonging to the genera Anabaena, Aphanizomenon, Calothrix, Cylindrospermum, Nostoc, Microcystis and Planktothrix were analysed. The identities of the major peaks were confirmed by MS. Correspondence analysis of the data revealed three distinct groups formed by the Microcystis strains, the Nostoc/Planktothrix strains and the Anabaena/Aphanizomenon/Cylindrospermum strains. The Calothrix strain did not cluster with the other heterocystous cyanobacteria, supporting its morphological classification separate from the Nostocaceae family. The presence of large amounts of the fatty acids 18:30omega6,9,12c and 18:0 iso distinguished the Microcystis strains from the other cyanobacteria studied. The high content of 16:1omega7c grouped the Nostoc strains with the Planktothrix strains. A free-living strain of Nostoc contained 16:1omegao5c and 16: 1omega7c (about 1: 1), separating it from the symbiotic Nostoc strain and the Planktothrix strains. the strains of Anabaena, Aphanizomenon and Cylindrospermum grouped tightly and were characterized by the presence of 16:1omega9c and 16:0 anteiso fatty acids. Correspondence analysis of Anabaena, Aphanizomenon and Cylindrospermum showed that all hepatotoxic Anabaena strains grouped together, whereas the non-toxic and neurotoxic Anabaena strains grouped with the non-toxic Aphanizomenon strains.
Jeffrey R. Johansen - One of the best experts on this subject based on the ideXlab platform.
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komarekiella atlantica gen et sp nov Nostocaceae cyanobacteria a new subaerial taxon from the atlantic rainforest and kauai hawaii
Fottea, 2017Co-Authors: Guilherme Scotta Hentschke, Jeffrey R. Johansen, Marli Fátima Fiore, Nicole Pietrasiak, Janaina Rigonato, Celia Leite SantannaAbstract:Six strains of Cyanobacteria sampled in the Brazilian Atlantic rainforest and one strain from Kauai, Hawaii, were studied using morphological and molecular approaches, including 16S rRNA gene phylogenies and 16S-23S ITS secondary structures, and are herein described as Komarekilla atlantica gen. et sp. nov.. Morphologically they are similar to Nostoc, Desmonostoc, Halotia, and Mojavia and indistinguishable from Chlorogloeopsis. The parsimony and Bayesian phylogenies of the 16S rDNA show that these strains are close to nostocacean strains, in strongly supported clades and separated from all other genera. The secondary structures of the 16S-23S ITS were very consistent between strains of K. atlantica, but distinctly different from structures in other close taxa. Of special note, the Hawaiian strain of K. atlantica had 16S sequence identities of 99.5-100% to the Brazilian strains, and 16S-23S ITS sequence identities of 99.4-99.8% to the Brazilian strains, and consequently likely represents a very recent introduction of the species to Kauai from South America, the geographic source of many of the non-native plants in the Hawaiian Archipelago.
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roholtiella gen nov nostocales cyanobacteria a tapering and branching cyanobacteria of the family Nostocaceae
Phytotaxa, 2015Co-Authors: Markéta Bohunická, Jeffrey R. Johansen, Nicole Pietrasiak, Esther Berrendero Gomez, Tomas Hauer, Lira A Gaysina, Alena LukešováAbstract:A total of 16 strains phylogenetically placed within the Nostocaceae were found to possess morphological features of the Rivulariaceae and Tolypothrichaceae (tapering trichomes and single false branching, respectively) in addition to their typical Nostocacean features (production of arthrospores in series). These strains formed a strongly supported clade separate from other strains that are phylogenetically and morphologically close. We describe four new species within the genus Roholtiella gen. nov. The four species include three distinguishable morphotypes. Roholtiella mojaviensis and R. edaphica are morphologically distinct from each other and from the other two species, R. fluviatilis and R. bashkiriorum . Roholtiella fluviatilis and R. bashkiriorum are cryptic species with respect to each other. All four species are easily distinguished based on the sequence of the 16S-23S ITS regions, in particular the flanking regions to the conserved Box-B and V3 helices. The species are further established by the elevated p-distance between species that is much reduced among strains within the same species. Calochaete cimrmanii, a recently described tapering species from tropical biomes, is the most likely sister taxon to Roholtiella.
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Morphological and molecular characterization within 26 strains of the genus Cylindrospermum (Nostocaceae, Cyanobacteria), with descriptions of three new species.
Journal of phycology, 2014Co-Authors: Jeffrey R. Johansen, Markéta Bohunická, Alena Lukešová, Kristýna Hrčková, Melissa A. Vaccarino, Nicholas M. ChesarinoAbstract:Twenty-six strains morphologically identified as Cylindrospermum as well as the closely related taxon Cronbergia siamensis were examined microscopically as well as phylogenetically using sequence data for the 16S rRNA gene and the 16S-23S internal transcribed spacer (ITS) region. Phylogenetic analysis of the 16S rRNA revealed three distinct clades. The clade we designate as Cylindrospermum sensu stricto contained all five of the foundational species, C. maius, C. stagnale, C. licheniforme, C. muscicola, and C. catenatum. In addition to these taxa, three species new to science in this clade were described: C. badium, C. moravicum, and C. pellucidum. Our evidence indicated that Cronbergia is a later synonym of Cylindrospermum. The phylogenetic position of Cylindrospermum within the Nostocaceae was not clearly resolved in our analyses. Cylindrospermum is unusual among cyanobacterial genera in that the morphological diversity appears to be more evident than sequence divergence. Taxa were clearly separable using morphology, but had very high percent similarity among ribosomal sequences. Given the high diversity we noted in this study, we conclude that there is likely much more diversity remaining to be described in this genus.
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Aulosira Bohemensis sp. nov.: Further Phylogenetic Uncertainty at The Base of The Nostocales (Cyanobacteria)
Phycologia, 2009Co-Authors: Alena Lukešová, Jeffrey R. Johansen, Michael P. Martin, Dale A. CasamattaAbstract:Abstract A. Lukesova, J.R. Johansen, M.P. Martin and D.A. Casamatta. 2009. Aulosira bohemensis sp. nov.: further phylogenetic uncertainty at the base of the Nostocales (Cyanobacteria). Phycologia 48: 118–129. DOI: 10.2216/08-56.1 Aulosira bohemensis sp. nov. was isolated from a wet meadow soil in South Bohemia, Czech Republic. It shares all the features of the majority of other Aulosira species, including isopolar development with intercalary heterocytes and apoheterocytic akinete development. It differs from all other species through the production of hormogonia perpendicular to the trichome axis following akinete germination. Morphologically the genus Aulosira appears closest to Nodularia, however, phylogenetic placement of A. bohemensis based on 16S rRNA was distant from that taxon. Aulosira falls within the Nostocaceae, with possible sister taxa in Trichormus, Mojavia and Nostoc. Despite the variety of phylogenetic analyses performed, we were unable to obtain bootstrap support for its position in any ...
Alena Lukešová - One of the best experts on this subject based on the ideXlab platform.
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a new microcystin producing nostoc strain discovered in broad toxicological screening of non planktic Nostocaceae cyanobacteria
Toxicon, 2018Co-Authors: Andreja Kust, Alena Lukešová, Pavel Hrouzek, Klara řehakova, Petra Urajova, Kateřina Capkova, Lenka Stenclova, Eliska Kozlikovazapomělova, Olga Lepsovaskacelova, Jan MaresAbstract:Benthic cyanobacteria recognized as producers of natural products, including cyanotoxins, have been neglected for systematic toxicological studies. Thus, we have performed a broad study investigating cyanotoxin potential of 311 non-planktic nostocacean representatives combining molecular and chemical analyses. Out of these, a single strain Nostoc sp. Treb K1/5, was identified as a new microcystin producer. Microcystins [Asp3]MC-YR, [Asp3]MC-FR, [Asp3]MC-HtyR and Ala-Leu/Ile-Asp-Arg-Adda-Glu-Mdha are reported for the first time from the genus Nostoc. All the studied strains were also analyzed for the occurrence of nodularins, cylindrospermopsin and (homo)anatoxin-a, yet no novel producer has been discovered. Our findings indicate rare occurrence of the common cyanotoxins in non-planktic Nostocaceae which is in contrast with frequent reports of cyanotoxin producers among phylogenetically closely related planktic cyanobacteria.
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roholtiella gen nov nostocales cyanobacteria a tapering and branching cyanobacteria of the family Nostocaceae
Phytotaxa, 2015Co-Authors: Markéta Bohunická, Jeffrey R. Johansen, Nicole Pietrasiak, Esther Berrendero Gomez, Tomas Hauer, Lira A Gaysina, Alena LukešováAbstract:A total of 16 strains phylogenetically placed within the Nostocaceae were found to possess morphological features of the Rivulariaceae and Tolypothrichaceae (tapering trichomes and single false branching, respectively) in addition to their typical Nostocacean features (production of arthrospores in series). These strains formed a strongly supported clade separate from other strains that are phylogenetically and morphologically close. We describe four new species within the genus Roholtiella gen. nov. The four species include three distinguishable morphotypes. Roholtiella mojaviensis and R. edaphica are morphologically distinct from each other and from the other two species, R. fluviatilis and R. bashkiriorum . Roholtiella fluviatilis and R. bashkiriorum are cryptic species with respect to each other. All four species are easily distinguished based on the sequence of the 16S-23S ITS regions, in particular the flanking regions to the conserved Box-B and V3 helices. The species are further established by the elevated p-distance between species that is much reduced among strains within the same species. Calochaete cimrmanii, a recently described tapering species from tropical biomes, is the most likely sister taxon to Roholtiella.
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variable phenotypes
2014Co-Authors: Klára Řeháková, Alena Lukešová, Eliška Zapomělová, Jan Mares, Pavel HrouzekAbstract:Nodularia (Cyanobacteria, Nostocaceae): a phylogenetically uniform genus wit
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nodularia cyanobacteria Nostocaceae a phylogenetically uniform genus with variable phenotypes
Phytotaxa, 2014Co-Authors: Klara řehakova, Alena Lukešová, Eliška Zapomělová, Jan Mares, Kateřina Bernardova, Pavel HrouzekAbstract:The taxonomy of cyanobacteria currently faces the challenge of overhauling the traditional system to better reflect the results of phylogenetic analyses. In the present study, we assessed the phylogenetic position, morphological variability, ability to produce the toxin nodularin, and source habitat of 17 benthic and soil isolates of Nodularia . A combined analysis of two loci (partial 16S rRNA gene and rbc LX region) confirmed the genus as a monophyletic unit and the close relationship of its members. However, the taxonomic resolution at the subgeneric level was extremely problematic. The phylogenetic clustering did not show any reasonable congruence with either morphological or ecological features commonly used to separate taxa in heterocytous cyanobacteria. Despite the near phylogenetic similarity of planktonic, benthic and soil Nodularia strains, we did not find any new nodularin-producing strains among the non-planktonic isolates. The relatively low variability in conserved molecular markers within the genus Nodularia exemplifies the limitations of the currently accepted taxonomic workflow and polyphasic approach. Elucidation of mechanisms that drive the phenotypic variability in such groups presents a major challenge in cyanobacterial research.
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Morphological and molecular characterization within 26 strains of the genus Cylindrospermum (Nostocaceae, Cyanobacteria), with descriptions of three new species.
Journal of phycology, 2014Co-Authors: Jeffrey R. Johansen, Markéta Bohunická, Alena Lukešová, Kristýna Hrčková, Melissa A. Vaccarino, Nicholas M. ChesarinoAbstract:Twenty-six strains morphologically identified as Cylindrospermum as well as the closely related taxon Cronbergia siamensis were examined microscopically as well as phylogenetically using sequence data for the 16S rRNA gene and the 16S-23S internal transcribed spacer (ITS) region. Phylogenetic analysis of the 16S rRNA revealed three distinct clades. The clade we designate as Cylindrospermum sensu stricto contained all five of the foundational species, C. maius, C. stagnale, C. licheniforme, C. muscicola, and C. catenatum. In addition to these taxa, three species new to science in this clade were described: C. badium, C. moravicum, and C. pellucidum. Our evidence indicated that Cronbergia is a later synonym of Cylindrospermum. The phylogenetic position of Cylindrospermum within the Nostocaceae was not clearly resolved in our analyses. Cylindrospermum is unusual among cyanobacterial genera in that the morphological diversity appears to be more evident than sequence divergence. Taxa were clearly separable using morphology, but had very high percent similarity among ribosomal sequences. Given the high diversity we noted in this study, we conclude that there is likely much more diversity remaining to be described in this genus.
Luna Viggiano De ,alvarenga - One of the best experts on this subject based on the ideXlab platform.
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extending the ecological distribution of desmonostoc genus proposal of desmonostoc salinum sp nov a novel cyanobacteria from a saline alkaline lake
International Journal of Systematic and Evolutionary Microbiology, 2018Co-Authors: Luna Viggiano De ,alvarenga, Marcelo Gomes Marcal Vieira Vaz, Diego Bonaldo Genuario, Alberto A Estevesferreira, Allan Victor Martins Almeida, Naira Valle De Castro, Claudineia Lizieri, Jose Joao Lelis Leal De SouzaAbstract:Cyanobacteria is an ancient phylum of oxygenic photosynthetic microorganisms found in almost all environments of Earth. In recent years, the taxonomic placement of some cyanobacterial strains, including those belonging to the genus Nostocsensu lato, have been reevaluated by means of a polyphasic approach. Thus, 16S rRNA gene phylogeny and 16S-23S internal transcribed spacer (ITS) secondary structures coupled with morphological, ecological and physiological data are considered powerful tools for a better taxonomic and systematics resolution, leading to the description of novel genera and species. Additionally, underexplored and harsh environments, such as saline-alkaline lakes, have received special attention given they can be a source of novel cyanobacterial taxa. Here, a filamentous heterocytous strain, Nostocaceae CCM-UFV059, isolated from Laguna Amarga, Chile, was characterized applying the polyphasic approach; its fatty acid profile and physiological responses to salt (NaCl) were also determined. Morphologically, this strain was related to morphotypes of the Nostocsensu lato group, being phylogenetically placed into the typical cluster of the genus Desmonostoc. CCM-UFV059 showed identity of the 16S rRNA gene as well as 16S-23S secondary structures that did not match those from known described species of the genus Desmonostoc, as well as distinct ecological and physiological traits. Taken together, these data allowed the description of the first strain of a member of the genus Desmonostoc from a saline-alkaline lake, named Desmonostoc salinum sp. nov., under the provisions of the International Code of Nomenclature for algae, fungi and plants. This finding extends the ecological coverage of the genus Desmonostoc, contributing to a better understanding of cyanobacterial diversity and systematics.
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Physiological responses of cyanobacteria of the Nostocaceae family under salt stress
Universidade Federal de Viçosa, 2015Co-Authors: Luna Viggiano De ,alvarengaAbstract:Cianobactérias são procariotos fotossintetizantes amplamente distribuídos em todo o globo terrestre, apresentando mecanismos de adaptação e diversas vias metabólicas eficazes a condições ambientais limitantes à maioria dos seres vivos. Não obstante, as cianobactérias são organismos vantajosos para aplicações industriais, em função do seu rápido crescimento em comparação as plantas, necessidades nutricionais simples (luz solar, água e CO2 principalmente), e possibilidade de manipulação genética. Devido à sua diversidade natural e capacidade de crescer em diversos habitats, como áreas impróprias à agricultura, há uma crescente tendência na exploração de cianobactérias para a produção de biomassa e biocombustíveis. Ademais, esses organismos mostram-se adequados à análise e entendimento dos mecanismos adaptativos desenvolvidos em resposta às mudanças nas condições ambientais. Este projeto buscou analisar a fisiologia e o metabolismo de uma cianobactéria (UFV059) coletada em ambiente hipersalino (salinidade entre 77-237 gL-1) e comparar com a cepa modelo da família Nostocaceae, PCC7120. Os resultados obtidos indicam uma alta tolerância ao estresse salino pela cepa UFV059, apresentando crescimento em meio suplementado com até 500 mM de NaCl e bem como em DL50 nove vezes superior a observada para cepa modelo PCC7120. De maneira interessante, a cepa UFV059 apresentou aumento na concentração de clorofila a quando exposta a concentrações de 250 e 500 mM de NaCl, o que poderia culminar na manutenção de taxas fotossintéticas e consequentemente maior disponibilidade energética para os processos de aclimatação. Ademais, a cepa UFV059 sobreviveu a concentrações superiores a 1M apresentando extensa diferenciação celular, o que indica uma extensa reprogramação metabólica. A tolerância observada na UFV059 ocorreu muito provavelmente em função da presença de um aparato proteíco adaptado a ambientes salinos, bem como pela maior produção de EPS que restringiria, ao menos parcialmente, a entrada de cátions. Cumpre mencionar que o estresse salino representa um grande desafio na viabilização econômica do uso de cianobactérias em escala industrial, por meio do cultivo em águas salobras ou residuais. Essa caracterização inicial possibilitou a identificação parcial de alguns dos mecanismos de tolerância na cepa UFV059; porém, uma caracterização molecular se faz necessária para compreender melhor esta cepa, até então desconhecida e podem, em longo prazo, contribuir para o desenvolvimento de cianobactérias e plantas tolerantes a alta salinidade através da engenharia genética.Cyanobacteria are photosynthetic microorganisms that occupy diverse ecological niches presenting thus enormous diversity in terms of habitat, physiology, morphology, metabolic capacities and molecular properties. Cyanobacteria are also organisms advantageous for industrial applications since they have rapid cell growth, basic nutritional needs (sunlight, water, and CO2), and great potential to be genetically modified. Due to its natural diversity and ability to grow in a variety of habitats, such as unsuitable agricultural areas, there is an increasing interest in the exploration of cyanobacteria for the production of biomass and biofuels. Moreover, cyanobacteria have been proven to be adequate for the analysis and understanding of adaptive mechanisms in response to changing environmental conditions. Thus, the main goals of this research initiative were to analyze both the physiology and metabolism of a cyanobacteria strain (UFV059) collected in a hypersaline environment (with salinity between 77-237 g L-1) and compare it with the model strain of the Nostocaceae family, PCC7120. The results obtained indicates that the strain UFV059 display high tolerance to salt stress, as demonstrated by its ability to sustain grow in medium supplemented with up to 500 mM of NaCl as well as containing LD50 nine times higher than observed for PCC7120. Surprisingly, UFV059 showed increased chlorophyll contents when exposed to 250 and 500 mM NaCl, which might be associated with the maintenance of photosynthetic rates and consequently allowing higher energy availability for acclimatization process. Furthermore, UFV059 survived to concentrations higher than 1M displaying extensive cell differentiation, which indicates an extensive metabolic reprogramming. The higher salt tolerance observed in UFV059 is most likely due to the presence of one previous available protein apparatus adapted to saline environments, as well as to the higher production of EPS that would restrict, at least partially, the cations entry. It is important to mention that salt stress is one major challenge for the economic viability of cyanobacteria usage on an industrial scale through cultivation in brackish or waste water. The results of this initial characterization allowed the partial identification of some tolerance mechanisms in UFV059; however, a molecular characterization is still required to enhance our understanding regarding this strain, that in the long term might contribute to the development of both cyanobacteria and plants displaying high salinity tolerance through genetic engineering
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Physiological responses of cyanobacteria of the Nostocaceae family under salt stress
'Universidade Federal de Vicosa', 2015Co-Authors: Luna Viggiano De ,alvarengaAbstract:Cianobactérias são procariotos fotossintetizantes amplamente distribuídos em todo o globo terrestre, apresentando mecanismos de adaptação e diversas vias metabólicas eficazes a condições ambientais limitantes à maioria dos seres vivos. Não obstante, as cianobactérias são organismos vantajosos para aplicações industriais, em função do seu rápido crescimento em comparação as plantas, necessidades nutricionais simples (luz solar, água e CO2 principalmente), e possibilidade de manipulação genética. Devido à sua diversidade natural e capacidade de crescer em diversos habitats, como áreas impróprias à agricultura, há uma crescente tendência na exploração de cianobactérias para a produção de biomassa e biocombustíveis. Ademais, esses organismos mostram-se adequados à análise e entendimento dos mecanismos adaptativos desenvolvidos em resposta às mudanças nas condições ambientais. Este projeto buscou analisar a fisiologia e o metabolismo de uma cianobactéria (UFV059) coletada em ambiente hipersalino (salinidade entre 77-237 gL-1) e comparar com a cepa modelo da família Nostocaceae, PCC7120. Os resultados obtidos indicam uma alta tolerância ao estresse salino pela cepa UFV059, apresentando crescimento em meio suplementado com até 500 mM de NaCl e bem como em DL50 nove vezes superior a observada para cepa modelo PCC7120. De maneira interessante, a cepa UFV059 apresentou aumento na concentração de clorofila a quando exposta a concentrações de 250 e 500 mM de NaCl, o que poderia culminar na manutenção de taxas fotossintéticas e consequentemente maior disponibilidade energética para os processos de aclimatação. Ademais, a cepa UFV059 sobreviveu a concentrações superiores a 1M apresentando extensa diferenciação celular, o que indica uma extensa reprogramação metabólica. A tolerância observada na UFV059 ocorreu muito provavelmente em função da presença de um aparato proteíco adaptado a ambientes salinos, bem como pela maior produção de EPS que restringiria, ao menos parcialmente, a entrada de cátions. Cumpre mencionar que o estresse salino representa um grande desafio na viabilização econômica do uso de cianobactérias em escala industrial, por meio do cultivo em águas salobras ou residuais. Essa caracterização inicial possibilitou a identificação parcial de alguns dos mecanismos de tolerância na cepa UFV059; porém, uma caracterização molecular se faz necessária para compreender melhor esta cepa, até então desconhecida e podem, em longo prazo, contribuir para o desenvolvimento de cianobactérias e plantas tolerantes a alta salinidade através da engenharia genética.Cyanobacteria are photosynthetic microorganisms that occupy diverse ecological niches presenting thus enormous diversity in terms of habitat, physiology, morphology, metabolic capacities and molecular properties. Cyanobacteria are also organisms advantageous for industrial applications since they have rapid cell growth, basic nutritional needs (sunlight, water, and CO2), and great potential to be genetically modified. Due to its natural diversity and ability to grow in a variety of habitats, such as unsuitable agricultural areas, there is an increasing interest in the exploration of cyanobacteria for the production of biomass and biofuels. Moreover, cyanobacteria have been proven to be adequate for the analysis and understanding of adaptive mechanisms in response to changing environmental conditions. Thus, the main goals of this research initiative were to analyze both the physiology and metabolism of a cyanobacteria strain (UFV059) collected in a hypersaline environment (with salinity between 77-237 g L-1) and compare it with the model strain of the Nostocaceae family, PCC7120. The results obtained indicates that the strain UFV059 display high tolerance to salt stress, as demonstrated by its ability to sustain grow in medium supplemented with up to 500 mM of NaCl as well as containing LD50 nine times higher than observed for PCC7120. Surprisingly, UFV059 showed increased chlorophyll contents when exposed to 250 and 500 mM NaCl, which might be associated with the maintenance of photosynthetic rates and consequently allowing higher energy availability for acclimatization process. Furthermore, UFV059 survived to concentrations higher than 1M displaying extensive cell differentiation, which indicates an extensive metabolic reprogramming. The higher salt tolerance observed in UFV059 is most likely due to the presence of one previous available protein apparatus adapted to saline environments, as well as to the higher production of EPS that would restrict, at least partially, the cations entry. It is important to mention that salt stress is one major challenge for the economic viability of cyanobacteria usage on an industrial scale through cultivation in brackish or waste water. The results of this initial characterization allowed the partial identification of some tolerance mechanisms in UFV059; however, a molecular characterization is still required to enhance our understanding regarding this strain, that in the long term might contribute to the development of both cyanobacteria and plants displaying high salinity tolerance through genetic engineering.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio
Nicholas M. Chesarino - One of the best experts on this subject based on the ideXlab platform.
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Morphological and molecular characterization within 26 strains of the genus Cylindrospermum (Nostocaceae, Cyanobacteria), with descriptions of three new species.
Journal of phycology, 2014Co-Authors: Jeffrey R. Johansen, Markéta Bohunická, Alena Lukešová, Kristýna Hrčková, Melissa A. Vaccarino, Nicholas M. ChesarinoAbstract:Twenty-six strains morphologically identified as Cylindrospermum as well as the closely related taxon Cronbergia siamensis were examined microscopically as well as phylogenetically using sequence data for the 16S rRNA gene and the 16S-23S internal transcribed spacer (ITS) region. Phylogenetic analysis of the 16S rRNA revealed three distinct clades. The clade we designate as Cylindrospermum sensu stricto contained all five of the foundational species, C. maius, C. stagnale, C. licheniforme, C. muscicola, and C. catenatum. In addition to these taxa, three species new to science in this clade were described: C. badium, C. moravicum, and C. pellucidum. Our evidence indicated that Cronbergia is a later synonym of Cylindrospermum. The phylogenetic position of Cylindrospermum within the Nostocaceae was not clearly resolved in our analyses. Cylindrospermum is unusual among cyanobacterial genera in that the morphological diversity appears to be more evident than sequence divergence. Taxa were clearly separable using morphology, but had very high percent similarity among ribosomal sequences. Given the high diversity we noted in this study, we conclude that there is likely much more diversity remaining to be described in this genus.
