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Sample records for potential microcystin-producing cyanobacteria

  1. UVB radiation as a potential selective factor favoring microcystin producing bloom forming Cyanobacteria.

    PubMed

    Ding, Yi; Song, Lirong; Sedmak, Bojan

    2013-01-01

    Due to the stratospheric ozone depletion, several organisms will become exposed to increased biologically active UVB (280-320 nm) radiation, not only at polar but also at temperate and tropical latitudes. Bloom forming cyanobacteria are exposed to UVB radiation on a mass scale, particularly during the surface bloom and scum formation that can persist for long periods of time. All buoyant species of cyanobacteria are at least periodically exposed to higher irradiation during their vertical migration to the surface that usually occurs several times a day. The aim of this study is to assess the influence on cyanobacteria of UVB radiation at realistic environmental intensities. The effects of two UVB intensities of 0.5 and 0.99 W/m(2) in up to 0.5 cm water depth were studied in vitro on Microcystis aeruginosa strains, two microcystin producing and one non-producing. After UVB exposure their ability to proliferate was estimated by cell counting, while cell fitness and integrity were evaluated using light microscopy, autofluorescence and immunofluorescence. Gene damage was assessed by TUNEL assay and SYBR Green staining of the nucleoide area. We conclude that UVB exposure causes damage to the genetic material, cytoskeletal elements, higher sedimentation rates and consequent cell death. In contrast to microcystin producers (PCC7806 and FACHB905), the microcystin non-producing strain PCC7005 is more susceptible to the deleterious effects of radiation, with weak recovery ability. The ecological relevance of the results is discussed using data from eleven years' continuous UVB radiation measurements within the area of Ljubljana city (Slovenia, Central Europe). Our results suggest that increased solar radiation in temperate latitudes can have its strongest effect during cyanobacterial bloom formation in spring and early summer. UVB radiation in this period may significantly influence strain composition of cyanobacterial blooms in favor of microcystin producers. PMID:24058503

  2. UVB Radiation as a Potential Selective Factor Favoring Microcystin Producing Bloom Forming Cyanobacteria

    PubMed Central

    Ding, Yi; Song, Lirong; Sedmak, Bojan

    2013-01-01

    Due to the stratospheric ozone depletion, several organisms will become exposed to increased biologically active UVB (280–320 nm) radiation, not only at polar but also at temperate and tropical latitudes. Bloom forming cyanobacteria are exposed to UVB radiation on a mass scale, particularly during the surface bloom and scum formation that can persist for long periods of time. All buoyant species of cyanobacteria are at least periodically exposed to higher irradiation during their vertical migration to the surface that usually occurs several times a day. The aim of this study is to assess the influence on cyanobacteria of UVB radiation at realistic environmental intensities. The effects of two UVB intensities of 0.5 and 0.99 W/m2 in up to 0.5 cm water depth were studied in vitro on Microcystis aeruginosa strains, two microcystin producing and one non-producing. After UVB exposure their ability to proliferate was estimated by cell counting, while cell fitness and integrity were evaluated using light microscopy, autofluorescence and immunofluorescence. Gene damage was assessed by TUNEL assay and SYBR Green staining of the nucleoide area. We conclude that UVB exposure causes damage to the genetic material, cytoskeletal elements, higher sedimentation rates and consequent cell death. In contrast to microcystin producers (PCC7806 and FACHB905), the microcystin non-producing strain PCC7005 is more susceptible to the deleterious effects of radiation, with weak recovery ability. The ecological relevance of the results is discussed using data from eleven years’ continuous UVB radiation measurements within the area of Ljubljana city (Slovenia, Central Europe). Our results suggest that increased solar radiation in temperate latitudes can have its strongest effect during cyanobacterial bloom formation in spring and early summer. UVB radiation in this period may significantly influence strain composition of cyanobacterial blooms in favor of microcystin producers. PMID

  3. Molecular characterization of potential microcystin-producing cyanobacteria in Lake Ontario embayments and nearshore waters.

    PubMed

    Hotto, A M; Satchwell, M F; Boyer, G L

    2007-07-01

    The distribution and genotypic variation of potential microcystin (MC) producers along the southern and eastern shores of Lake Ontario in 2001 and 2003 were examined using a suite of PCR primers. Cyanobacterial, Microcystis sp., and Microcystis-specific toxin primer sets identified shoreline distribution of cyanobacterial DNA (in 97% of the stations) and MC synthetase genes (in 50% of the stations). Sequence analysis of a partial mcyA amplicon targeting Microcystis, Anabaena, and Planktothrix species indicated that the Microcystis sp. genotype was the dominant MC genotype present and revealed a novel Microcystis-like sequence containing a 6-bp insert. Analysis of the same samples with genus-specific mcyE primers confirmed that the Microcystis sp. genotype was the dominant potential MC producer. Genotype compositions within embayments were relatively homogenous compared to those for shoreline and tributary samples. MC concentrations along the shoreline exhibited both temporal and spatial differences as evidenced by the protein phosphatase inhibition assay, at times exceeding the World Health Organization guideline value for drinking water of 1.0 microg MC-LReq liter(-1). MC genotypes are widespread along the New York State shoreline of Lake Ontario, appear to originate nearshore, and can be carried through the lake via wind and surface water current patterns.

  4. Occurrence of microcystin-producing cyanobacteria in Ugandan freshwater habitats

    PubMed Central

    Okello, William; Portmann, Cyril; Erhard, Marcel; Gademann, Karl; Kurmayer, Rainer

    2011-01-01

    Microcystins (MCs) are cyclic heptapeptides that are the most abundant toxins produced by cyanobacteria in freshwater. The phytoplankton of many freshwater lakes in Eastern Africa is dominated by cyanobacteria. Less is known, however, on the occurrence of MC producers and the production of MCs. Twelve Ugandan freshwater habitats ranging from mesotrophic to hypertrophic conditions were sampled in May and June of 2004 and April of 2008 and were analyzed for their physico-chemical parameters, phytoplankton composition, and MC concentrations. Among the group of the potential MC-producing cyanobacteria, Anabaena (0 - 107 cells ml−1) and Microcystis (103 - 107 cells ml−1) occurred most frequently and dominated in eutrophic systems. A significant linear relationship (n = 31, r2 = 0.38, p < 0.001) between the Microcystis cell numbers and MC concentration (1.3-93 fg of MC cell−1) was observed. Beside [MeAsp3, Mdha7]-MC-RR two new microcystins, [Asp3]-MC-RY and [MeAsp3]-MC-RY were isolated and their constitution assigned by LC-MS2. In order to identify the MC-producing organism in the water samples (i), the conserved aminotransferase domain part of the mcyE gene that is indicative of MC production was amplified by general primers and cloned and sequenced, and (ii), genus-specific primers were used to amplify the mcyE gene of the genera Microcystis, Anabaena, and Planktothrix. Only mcyE genotypes that are indicative of Microcystis sp. were obtained via the environmental cloning approach (337 bp, 96.1%-96.7% similarity to the Microcystis aeruginosa strain PCC7806). Accordingly, only the mcyE primers, which are specific for Microcystis, revealed PCR products. We concluded that Microcystis is the major MC-producer in Ugandan freshwater. PMID:19609871

  5. Phylogenies of microcystin-producing cyanobacteria in the lower Laurentian Great Lakes suggest extensive genetic connectivity.

    PubMed

    Davis, Timothy W; Watson, Susan B; Rozmarynowycz, Mark J; Ciborowski, Jan J H; McKay, Robert Michael; Bullerjahn, George S

    2014-01-01

    Lake St. Clair is the smallest lake in the Laurentian Great Lakes system. MODIS satellite imagery suggests that high algal biomass events have occurred annually along the southern shore during late summer. In this study, we evaluated these events and tested the hypothesis that summer bloom material derived from Lake St. Clair may enter Lake Erie via the Detroit River and represent an overlooked source of potentially toxic Microcystis biomass to the western basin of Lake Erie. We conducted a seasonally and spatially resolved study carried out in the summer of 2013. Our goals were to: 1) track the development of the 2013 summer south-east shore bloom 2) conduct a spatial survey to characterize the extent of toxicity, taxonomic diversity of the total phytoplankton population and the phylogenetic diversity of potential MC-producing cyanobacteria (Microcystis, Planktothrix and Anabaena) during a high biomass event, and 3) compare the strains of potential MC-producers in Lake St. Clair with strains from Lake Erie and Lake Ontario. Our results demonstrated a clear predominance of cyanobacteria during a late August bloom event, primarily dominated by Microcystis, which we traced along the Lake St. Clair coastline downstream to the Detroit River's outflow at Lake Erie. Microcystin levels exceeded the Province of Ontario Drinking Water Quality Standard (1.5 µg L(-1)) for safe drinking water at most sites, reaching up to five times this level in some areas. Microcystis was the predominant microcystin producer, and all toxic Microcystis strains found in Lake St. Clair were genetically similar to toxic Microcystis strains found in lakes Erie and Ontario. These findings suggest extensive genetic connectivity among the three systems.

  6. Phylogenies of Microcystin-Producing Cyanobacteria in the Lower Laurentian Great Lakes Suggest Extensive Genetic Connectivity

    PubMed Central

    Davis, Timothy W.; Watson, Susan B.; Rozmarynowycz, Mark J.; Ciborowski, Jan J. H.; McKay, Robert Michael; Bullerjahn, George S.

    2014-01-01

    Lake St. Clair is the smallest lake in the Laurentian Great Lakes system. MODIS satellite imagery suggests that high algal biomass events have occurred annually along the southern shore during late summer. In this study, we evaluated these events and tested the hypothesis that summer bloom material derived from Lake St. Clair may enter Lake Erie via the Detroit River and represent an overlooked source of potentially toxic Microcystis biomass to the western basin of Lake Erie. We conducted a seasonally and spatially resolved study carried out in the summer of 2013. Our goals were to: 1) track the development of the 2013 summer south-east shore bloom 2) conduct a spatial survey to characterize the extent of toxicity, taxonomic diversity of the total phytoplankton population and the phylogenetic diversity of potential MC-producing cyanobacteria (Microcystis, Planktothrix and Anabaena) during a high biomass event, and 3) compare the strains of potential MC-producers in Lake St. Clair with strains from Lake Erie and Lake Ontario. Our results demonstrated a clear predominance of cyanobacteria during a late August bloom event, primarily dominated by Microcystis, which we traced along the Lake St. Clair coastline downstream to the Detroit River's outflow at Lake Erie. Microcystin levels exceeded the Province of Ontario Drinking Water Quality Standard (1.5 µg L−1) for safe drinking water at most sites, reaching up to five times this level in some areas. Microcystis was the predominant microcystin producer, and all toxic Microcystis strains found in Lake St. Clair were genetically similar to toxic Microcystis strains found in lakes Erie and Ontario. These findings suggest extensive genetic connectivity among the three systems. PMID:25207941

  7. Microcystin-producing and non-producing cyanobacterial blooms collected from the Central India harbor potentially pathogenic Vibrio cholerae.

    PubMed

    Chaturvedi, Prashant; Kumar Agrawal, Manish; Nath Bagchi, Suvendra

    2015-05-01

    On the basis of relative abundance, frequency and biovolume, the important value index ranks were assigned to individual cyanobacteria in phytoplankton samples collected from fourteen water resources of Central India. The mcyABDE genes were detected in all the blooms with Microcystis (-aeruginosa, -viridis, -panniformis, -botrys) as being the major constituent morphospecies. On the other hand, blooms composed of primarily Oscillatoria (-limosa,-agardhii, -laetevirens) along with Anabaena, Nostoc, Phormidium and Spirulina as sub-dominant forms exhibited quite a patchy distribution of one or the other mcy genes. Fifty percent of Microcystis- but none of the Oscillatoria dominant blooms produced microcystins-RR and desmethyl-RR at 0.03-0.41mgg(-1) bloom dry mass. Traces of dissolved microcystin was detected in lake water, which is well below the WHO guideline. Irrespective of cyanobacterial composition and microcystin production ability, during the study period 43-64% of the cyanobacterial bloom samples exhibited association of viable but nonculturable forms of Vibrio cholerae O1 and O139, as evident from amplification of the antigen genes. We believe that spread of endemic cholera is the major threat associated with harmful algal blooms. PMID:25682583

  8. Microcystin-producing and non-producing cyanobacterial blooms collected from the Central India harbor potentially pathogenic Vibrio cholerae.

    PubMed

    Chaturvedi, Prashant; Kumar Agrawal, Manish; Nath Bagchi, Suvendra

    2015-05-01

    On the basis of relative abundance, frequency and biovolume, the important value index ranks were assigned to individual cyanobacteria in phytoplankton samples collected from fourteen water resources of Central India. The mcyABDE genes were detected in all the blooms with Microcystis (-aeruginosa, -viridis, -panniformis, -botrys) as being the major constituent morphospecies. On the other hand, blooms composed of primarily Oscillatoria (-limosa,-agardhii, -laetevirens) along with Anabaena, Nostoc, Phormidium and Spirulina as sub-dominant forms exhibited quite a patchy distribution of one or the other mcy genes. Fifty percent of Microcystis- but none of the Oscillatoria dominant blooms produced microcystins-RR and desmethyl-RR at 0.03-0.41mgg(-1) bloom dry mass. Traces of dissolved microcystin was detected in lake water, which is well below the WHO guideline. Irrespective of cyanobacterial composition and microcystin production ability, during the study period 43-64% of the cyanobacterial bloom samples exhibited association of viable but nonculturable forms of Vibrio cholerae O1 and O139, as evident from amplification of the antigen genes. We believe that spread of endemic cholera is the major threat associated with harmful algal blooms.

  9. Effects of elevated CO2 on dynamics of microcystin-producing and non-microcystin-producing strains during Microcystis blooms.

    PubMed

    Yu, Li; Kong, Fanxiang; Shi, Xiaoli; Yang, Zhen; Zhang, Min; Yu, Yang

    2015-01-01

    In an attempt to elucidate the effects of different CO2 concentrations (270, 380, and 750 μL/L) on the competition of microcystin-producing (MC-producing) and non-MC-producing Microcystis strains during dense cyanobacteria blooms, an in situ simulation experiment was conducted in the Meiliang Bay of Lake Taihu in the summer of 2012. The abundance of total Microcystis and MC-producing Microcystis genotypes was quantified based on the 16S rDNA and mcyD gene using real-time PCR. The results showed that atmospheric CO2 elevation would significantly decrease the pH value and increase the dissolved inorganic carbon (DIC) concentration. Changes in CO2 concentration did not show significant influence on the abundance of total Microcystis population. However, CO2 concentrations may be an important factor in determining the subpopulation structure of Microcystis. The enhancement of CO2 concentrations could largely increase the competitive ability of non-MC-producing over MC-producing Microcystis, resulting in a higher proportion of non-MC-producing subpopulation in treatments using high CO2 concentrations. Concurrently, MC concentration in water declined when CO2 concentrations were elevated. Therefore, we concluded that the increase of CO2 concentrations might decrease potential health risks of MC for human and animals in the future. PMID:25597684

  10. Cyanobacteria

    MedlinePlus

    ... By Syndrome Life Cycle Impacts Human Health Wildlife Ecosystems Socioeconomic Freshwater Regions Distribution - U.S. Distribution - World Maps ... Paralytic Shellfish Poisoning Cyanobacteria Medical Community ... cyanobacteria blooms are potential ...

  11. The localization of exogenous microcystin LR taken up by a non-microcystin producing cyanobacterium.

    PubMed

    Phelan, Richard R; Downing, Timothy G

    2014-10-01

    The effect of exogenous microcystin on non-microcystin producing cyanobacteria has not yet been extensively studied. Existing evidence for internalization of microcystin by cyanobacteria is based only on the presence of internalized radioisotopic label. Where a function or physiological role for microcystin has been proposed based on the molecule acting as a signalling molecule, the hypothetical function has not been demonstrated at the site of action in receiving cells. We therefore exposed Synechocystis PCC6803 to microcystin LR and showed that the microcystin-LR was both taken up by Synechocystis PCC6803 and localised in the thylakoid membranes, where it caused a decrease in photosystem II activity as has been shown for endogenous microcystin, without any negative effects on the cell's survival. PMID:25064273

  12. Changes in iTRAQ-Based Proteomic Profiling of the Cladoceran Daphnia magna Exposed to Microcystin-Producing and Microcystin-Free Microcystis aeruginosa.

    PubMed

    Lyu, Kai; Meng, Qingguo; Zhu, Xuexia; Dai, Daoxin; Zhang, Lu; Huang, Yuan; Yang, Zhou

    2016-05-01

    Global warming and increased nutrient fluxes cause cyanobacterial blooms in freshwater ecosystems. These phenomena have increased the concern for human health and ecosystem services. The mass occurrences of toxic cyanobacteria strongly affect freshwater zooplankton communities, especially the unselective filter feeder Daphnia. However, the molecular mechanisms of cyanobacterial toxicity remain poorly understood. This study is the first to combine the established body growth rate (BGR), which is an indicator of life-history fitness, with differential peptide labeling (iTRAQ)-based proteomics in Daphnia magna influenced by microcystin-producing (MP) and microcystin-free (MF) Microcystis aeruginosa. A significant decrease in BGR was detected when D. magna was exposed to MP or MF M. aeruginosa. Conducting iTRAQ proteomic analyses, we successfully identified and quantified 211 proteins with significant changes in expression. A cluster of orthologous groups revealed that M. aeruginosa-affected differential proteins were strongly associated with lipid, carbohydrate, amino acid, and energy metabolism. These parameters could potentially explain the reduced fitness based on the cost of the substance metabolism. PMID:27057760

  13. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae.

    PubMed

    Wijffels, René H; Kruse, Olaf; Hellingwerf, Klaas J

    2013-06-01

    Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments. Cyanobacteria are promising host organisms for the production of small molecules that can be secreted such as ethanol, butanol, fatty acids and other organic acids. Eukaryotic microalgae are interesting for products for which cellular storage is important such as proteins, lipids, starch and alkanes. For the development of new and promising lines of production, strains of both cyanobacteria and eukaryotic microalgae have to be improved. Transformation systems have been much better developed in cyanobacteria. However, several products would be preferably produced with eukaryotic microalgae. In the case of cyanobacteria a synthetic-systems biology approach has a great potential to exploit cyanobacteria as cell factories. For eukaryotic microalgae transformation systems need to be further developed. A promising strategy is transformation of heterologous (prokaryotic and eukaryotic) genes in established eukaryotic hosts such as Chlamydomonas reinhardtii. Experimental outdoor pilots under containment for the production of genetically modified cyanobacteria and microalgae are in progress. For full scale production risks of release of genetically modified organisms need to be assessed.

  14. Acute Exposure to Microcystin-Producing Cyanobacterium Microcystis aeruginosa Alters Adult Zebrafish (Danio rerio) Swimming Performance Parameters

    PubMed Central

    Kist, Luiza Wilges; Piato, Angelo Luis; da Rosa, João Gabriel Santos; Koakoski, Gessi; Barcellos, Leonardo José Gil; Yunes, João Sarkis; Bonan, Carla Denise; Bogo, Maurício Reis

    2011-01-01

    Microcystins (MCs) are toxins produced by cyanobacteria (blue-green algae), primarily Microcystis aeruginosa, forming water blooms worldwide. When an organism is exposed to environmental perturbations, alterations in normal behavioral patterns occur. Behavioral repertoire represents the consequence of a diversity of physiological and biochemical alterations. In this study, we assessed behavioral patterns and whole-body cortisol levels of adult zebrafish (Danio rerio) exposed to cell culture of the microcystin-producing cyanobacterium M. aeruginosa (MC-LR, strain RST9501). MC-LR exposure (100 μg/L) decreased by 63% the distance traveled and increased threefold the immobility time when compared to the control group. Interestingly, no significant alterations in the number of line crossings were found at the same MC-LR concentration and time of exposure. When animals were exposed to 50 and 100 μg/L, MC-LR promoted a significant increase (around 93%) in the time spent in the bottom portion of the tank, suggesting an anxiogenic effect. The results also showed that none of the MC-LR concentrations tested promoted significant alterations in absolute turn angle, path efficiency, social behavior, or whole-body cortisol level. These findings indicate that behavior is susceptible to MC-LR exposure and provide evidence for a better understanding of the ecological consequences of toxic algal blooms. PMID:22253623

  15. Acute Exposure to Microcystin-Producing Cyanobacterium Microcystis aeruginosa Alters Adult Zebrafish (Danio rerio) Swimming Performance Parameters.

    PubMed

    Kist, Luiza Wilges; Piato, Angelo Luis; da Rosa, João Gabriel Santos; Koakoski, Gessi; Barcellos, Leonardo José Gil; Yunes, João Sarkis; Bonan, Carla Denise; Bogo, Maurício Reis

    2011-01-01

    Microcystins (MCs) are toxins produced by cyanobacteria (blue-green algae), primarily Microcystis aeruginosa, forming water blooms worldwide. When an organism is exposed to environmental perturbations, alterations in normal behavioral patterns occur. Behavioral repertoire represents the consequence of a diversity of physiological and biochemical alterations. In this study, we assessed behavioral patterns and whole-body cortisol levels of adult zebrafish (Danio rerio) exposed to cell culture of the microcystin-producing cyanobacterium M. aeruginosa (MC-LR, strain RST9501). MC-LR exposure (100 μg/L) decreased by 63% the distance traveled and increased threefold the immobility time when compared to the control group. Interestingly, no significant alterations in the number of line crossings were found at the same MC-LR concentration and time of exposure. When animals were exposed to 50 and 100 μg/L, MC-LR promoted a significant increase (around 93%) in the time spent in the bottom portion of the tank, suggesting an anxiogenic effect. The results also showed that none of the MC-LR concentrations tested promoted significant alterations in absolute turn angle, path efficiency, social behavior, or whole-body cortisol level. These findings indicate that behavior is susceptible to MC-LR exposure and provide evidence for a better understanding of the ecological consequences of toxic algal blooms. PMID:22253623

  16. Identification of hepatotoxin-producing cyanobacteria by DNA-chip.

    PubMed

    Rantala, Anne; Rizzi, Ermanno; Castiglioni, Bianca; de Bellis, Gianluca; Sivonen, Kaarina

    2008-03-01

    We developed a new tool to detect and identify hepatotoxin-producing cyanobacteria of the genera Anabaena, Microcystis, Planktothrix, Nostoc and Nodularia. Genus-specific probe pairs were designed for the detection of the microcystin (mcyE) and nodularin synthetase genes (ndaF) of these five genera to be used with a DNA-chip. The method couples a ligation detection reaction, in which the polymerase chain reaction (PCR)-amplified mcyE/ndaF genes are recognized by the probe pairs, with a hybridization on a universal microarray. All the probe pairs specifically detected the corresponding mcyE/ndaF gene sequences when DNA from the microcystin- or nodularin-producing cyanobacterial strains were used as template in the PCR. Furthermore, the strict specificity of detection enabled identification of the potential hepatotoxin producers. Detection of the genes was very sensitive; only 1-5 fmol of the PCR product were needed to produce signal intensities that exceeded the set background threshold level. The genus-specific probe pairs also reliably detected potential microcystin producers in DNA extracted from six lake and four brackish water samples. In lake samples, the same microcystin producers were identified with quantitative real-time PCR analysis. The specificity, sensitivity and ability of the DNA-chip in simultaneously detecting all the main hepatotoxin producers make this method suitable for high-throughput analysis and monitoring of environmental samples.

  17. Preliminary Assessment of Cyanobacteria Diversity and Toxic Potential in Ten Freshwater Lakes in Selangor, Malaysia.

    PubMed

    Sinang, Som Cit; Poh, Keong Bun; Shamsudin, Syakirah; Sinden, Ann

    2015-10-01

    Toxic cyanobacteria blooms are increasing in magnitude and frequency worldwide. However, this issue has not been adequately addressed in Malaysia. Therefore, this study aims to better understand eutrophication levels, cyanobacteria diversity, and microcystin concentrations in ten Malaysian freshwater lakes. The results revealed that most lakes were eutrophic, with total phosphorus and total chlorophyll-a concentrations ranging from 15 to 4270 µg L(-1) and 1.1 to 903.1 µg L(-1), respectively. Cyanobacteria were detected in all lakes, and identified as Microcystis spp., Planktothrix spp., Phormidium spp., Oscillatoria spp., and Lyngbya spp. Microcystis spp. was the most commonly observed and most abundant cyanobacteria recorded. Semi-quantitative microcystin analysis indicated the presence of microcystin in all lakes. These findings illustrate the potential health risk of cyanobacteria in Malaysia freshwater lakes, thus magnifying the importance of cyanobacteria monitoring and management in Malaysian waterways.

  18. Identification of toxigenic Cyanobacteria of the genus Microcystis in the Curonian Lagoon (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Belykh, O. I.; Dmitrieva, O. A.; Gladkikh, A. S.; Sorokovikova, E. G.

    2013-02-01

    In 2002-2008, seasonal (April-November) monitoring of the phytoplankton in the Russian part of the Curonian Lagoon at five fixed sites was performed. A total of 91 Cyanobacteria, 100 Bacillariophyta, 280 Chlorophyta, 21 Cryptophyta, and 24 Dinophyta species were found. Six potentially toxic species of cyanobacteria: Aphanizomenon flos-aquae, Anabaena sp., Microcystis aeruginosa, M. viridis, M. wesenbergii, and Planktothrix agardhii dominated the phytoplankton biomass and caused water blooms. The seasonal average phytoplankton biomass ranged from 30 to 137 g/m3. The cyanobacteria's biomass varied from 10 to 113 g/m3 forming 30-82% of the total with a mean of 50%. With the aid of genetic markers (microcystin ( mcy) and nodularin synthetases), six variants of the microcystin-producing gene mcyE from the genus Microcystis were identified. Due to the intensive and lengthy blooms of potentially toxic and toxigenic cyanobacteria, the environmental conditions in the Curonian Lagoon appear unfavorable. The water should be monitored for cyanotoxins with analytical methods in order to determine if the area is safe for recreational use.

  19. Detection and identification of potentially toxic cyanobacteria in Polish water bodies.

    PubMed

    Głowacka, Joanna; Szefel-Markowska, Magdalena; Waleron, Małgorzata; Łojkowska, Ewa; Waleron, Krzysztof

    2011-01-01

    The main goal of this study was to determine the distribution of potentially toxic cyanobacteria in 39 selected Polish water bodies. From the water bodies with blooms and also from those in which blooms were not visible 87 samples were investigated. For the first time samples from ponds localized in villages with high agricultural activities were included. Lakes for which microcystin concentrations had been determined before were included as a reference for the research. The detection of cyanobacteria was conducted by microscopic observation as well as by PCR amplification of the rpoC1 gene fragment. Cyanobacteria were present in 75 out of 87 samples. The presence of potentially toxic cyanobacteria was detected by amplification of the mcyB and mcyE genes, which are involved in the biosynthesis of microcystins. Both genes were detected in 7 out of 9 blooms investigated. In the case of samples collected from water bodies in which blooms were not observed, the mcyB and mcyE genes were detected in 20 out of 36. In order to identify the cyanobacteria occurring in selected reservoirs, 16S plus ITS clone libraries were constructed. The method allowed distinguishing 18 different genotypes. After sequence analysis, cyanobacteria belonging to genera Microcystis, Planktothrix, Anabaena, Pseudanabaena, Synechocystis, Synechococcus and Woronichinia were identified. Results confirmed the usefulness of the rpoC1 and mcy genes for monitoring water bodies and detection of potentially toxic cyanobacteria. Application of molecular markers allowed detecting potentially toxic cyanobacteria before the bloom was visible. This is the first comprehensive study concerning cyanobacteria present in different types of Polish water bodies performed using molecular markers.

  20. Effects of trophic status on microcystin production and the dominance of cyanobacteria in the phytoplankton assemblage of Mediterranean reservoirs

    PubMed Central

    Mariani, Maria Antonietta; Padedda, Bachisio Mario; Kaštovský, Jan; Buscarinu, Paola; Sechi, Nicola; Virdis, Tomasa; Lugliè, Antonella

    2015-01-01

    The aim of our study was to evaluate the abundance of cyanobacteria and microcystins in four Sardinian reservoirs (Italy) characterised by different trophic status to define a reference picture for future changes. Increasing levels of eutrophication and the abundance of cyanobacteria are expected to occur due to climate change, especially in the southern Mediterranean. Consequently, an in-depth study of the occurrence of harmful cyanobacteria is important to develop appropriate management strategies for water resources at a local scale. Monthly samples were collected at one station in each reservoir over an 18-month period. The Analysis of similarity indicated that cyanobacterial abundance and species composition differed significantly among the reservoirs. The Redundancy analysis highlighted their relationship to trophic, hydrological and seasonal patterns. Spearman’s analysis indicated that there were significant correlations among the most important species (Planktothrix agardhii–rubescens group, Aphanizomenon flos-aquae and Dolichospermum planctonicum), nutrients and microcystins. We highlighted that the species composition during periods of maximum microcystin concentrations differed from those typically reported for other Mediterranean sites. We found new potential microcystin producers (Aphanizomenon klebahnii, Dolichospermum macrosporum and Dolichospermum viguieri), which emphasised the high diversity of cyanobacteria in the Mediterranean area and the need for detailed research at the local scale. PMID:26648532

  1. Sustainable life support on Mars - the potential roles of cyanobacteria

    NASA Astrophysics Data System (ADS)

    Verseux, Cyprien; Baqué, Mickael; Lehto, Kirsi; de Vera, Jean-Pierre P.; Rothschild, Lynn J.; Billi, Daniela

    2016-01-01

    Even though technological advances could allow humans to reach Mars in the coming decades, launch costs prohibit the establishment of permanent manned outposts for which most consumables would be sent from Earth. This issue can be addressed by in situ resource utilization: producing part or all of these consumables on Mars, from local resources. Biological components are needed, among other reasons because various resources could be efficiently produced only by the use of biological systems. But most plants and microorganisms are unable to exploit Martian resources, and sending substrates from Earth to support their metabolism would strongly limit the cost-effectiveness and sustainability of their cultivation. However, resources needed to grow specific cyanobacteria are available on Mars due to their photosynthetic abilities, nitrogen-fixing activities and lithotrophic lifestyles. They could be used directly for various applications, including the production of food, fuel and oxygen, but also indirectly: products from their culture could support the growth of other organisms, opening the way to a wide range of life-support biological processes based on Martian resources. Here we give insights into how and why cyanobacteria could play a role in the development of self-sustainable manned outposts on Mars.

  2. Role of environmental factors and toxic genotypes in the regulation of microcystins-producing cyanobacterial blooms.

    PubMed

    Gągała, Ilona; Izydorczyk, Katarzyna; Jurczak, Tomasz; Pawełczyk, Jakub; Dziadek, Jarosław; Wojtal-Frankiewicz, Adrianna; Jóźwik, Adam; Jaskulska, Aleksandra; Mankiewicz-Boczek, Joanna

    2014-02-01

    The aim of this study was to understand: (1) how environmental conditions can contribute to formation of Microcystis-dominated blooms in lowland, dam reservoirs in temperate climate-with the use of quantitative molecular monitoring, and (2) what is the role of toxic Microcystis genotypes in the bloom functioning. Monitoring of the Sulejow Reservoir in 2009 and 2010 in two sites Tresta (TR) and Bronislawow BR), which have different morphometry, showed that physicochemical conditions were always favorable for cyanobacterial bloom formation. In 2009, the average biomass of cyanobacteria reached 13 mg L(-1) (TR) and 8 mg L(-1) (BR), and in the second year, it decreased to approximately 1 mg L(-1) (TR and BR). In turns, the mean number of toxic Microcystis genotypes in the total Microcystis reached 1% in 2009, both in TR and BR, and in 2010, the number increased to 70% in TR and 14 % in BR. Despite significant differences in the biomass of cyanobacteria in 2009 and 2010, the mean microcystins (MCs) concentration and toxicity stayed at a similar level of approximately 1 μg L(-1). Statistical analysis indicated that water retention time was a factor that provided a significant difference between the two monitoring seasons and was considered a driver of the changes occurring in the Sulejow Reservoir. Hydrologic differences, which occurred between two studied years due to heavy flooding in Poland in 2010, influenced the decrease in number of Microcystis biomass by causing water disturbances and by lowering water temperature. Statistical analysis showed that Microcystis aeruginosa biomass and 16S rRNA gene copy number representing Microcystis genotypes in both years of monitoring could be predicted on the basis of total and dissolved phosphorus concentrations and water temperature. In present study, the number of mcyA gene copies representing toxic Microcystis genotypes could be predicted based on the biomass of M. aeruginosa. Moreover, MCs toxicity and concentration could

  3. Microcystic cyanobacteria causes mitochondrial membrane potential alteration and reactive oxygen species formation in primary cultured rat hepatocytes.

    PubMed Central

    Ding, W X; Shen, H M; Shen, Y; Zhu, H G; Ong, C N

    1998-01-01

    Cyanobacteria contamination of water has become a growing public health problem worldwide. Microcystis aeruginosa is one of the most common toxic cyanobacteria. It is capable of producing microcystins, a group of cyclic heptapeptide compounds with potent hepatotoxicity and tumor promotion activity. The present study investigated the effect of microcystic cyanobacteria on primary cultured rat hepatocytes by examining mitochondrial membrane potential (MMP) changes and intracellular reactive oxygen species (ROS) formation in cells treated with lyophilized freshwater microcystic cyanobacteria extract (MCE). Rhodamine 123 (Rh-123) was used as a fluorescent probe for changes in mitochondrial fluorescence intensity. The mitochondrial Rh-123 fluorescence intensity in MCE-treated hepatocytes, examined using a laser confocal microscope, responded in a dose- and time-dependent manner. The results thus indicate that the alteration of MMP might be an important event in the hepatotoxicity caused by cyanobacteria. Moreover, the parallel increase of ROS formation detected using another fluorescent probe, 2',7'-dichlorofluorescin diacetate also suggests the involvement of oxidative stress in the hepatotoxicity caused by cyanobacteria. The fact that MMP changes precede other cytotoxic parameters such as nuclear staining by propidium iodide and cell morphological changes suggests that mitochondrial damage is closely associated with MCE-induced cell injury in cultured rat hepatocytes. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:9637798

  4. Influence of zeta potential on the flocculation of cyanobacteria cells using chitosan modified soil.

    PubMed

    Li, Liang; Zhang, Honggang; Pan, Gang

    2015-02-01

    Using chitosan modified soil to flocculate and sediment algal cells has been considered as a promising strategy to combat cyanobacteria blooms in natural waters. However, the flocculation efficiency often varies with algal cells with different zeta potential (ZP) attributed to different growth phases or water conditions. This article investigated the relationship between ZP of Microcystis aeruginosa and its influence to the flocculation efficiency using chitosan modified soil. Results suggested that the optimal removal efficiency was obtained when the ZP was between -20.7 and -6.7 mV with a removal efficiency of more than 80% in 30 min and large floc size of >350 μm. When the algal cells were more negatively charged than -20.7 mV, the effect of chitosan modified soil was depressed (<60%) due to the insufficient charge density of chitosan to neutralize and destabilize the algal suspension. When the algal cells were less negative than -6.7 mV or even positively charged, a small floc size (<120 μm) was formed, which may be difficult to sink under natural water conditions. Therefore, manipulation of ZP provided a viable tool to improve the flocculation efficiency of chitosan modified soil and an important guidance for practical engineering of cyanobacteria bloom control.

  5. Chemical compounds toxic to invertebrates isolated from marine cyanobacteria of potential relevance to the agricultural industry.

    PubMed

    Essack, Magbubah; Alzubaidy, Hanin S; Bajic, Vladimir B; Archer, John A C

    2014-10-29

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review.

  6. Chemical Compounds Toxic to Invertebrates Isolated from Marine Cyanobacteria of Potential Relevance to the Agricultural Industry

    PubMed Central

    Essack, Magbubah; Alzubaidy, Hanin S.; Bajic, Vladimir B.; Archer, John A. C.

    2014-01-01

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review. PMID:25356733

  7. Molecular (PCR-DGGE) versus morphological approach: analysis of taxonomic composition of potentially toxic cyanobacteria in freshwater lakes

    PubMed Central

    2014-01-01

    Background The microscopic Utermöhl method is commonly used for the recognition of the presence and taxonomic composition of potentially toxic cyanobacteria and is especially useful for monitoring reservoirs used as drinking water, recreation and fishery resources. However, this method is time-consuming and does not allow potentially toxic and nontoxic cyanobacterial strains to be distinguished. We have developed a method based on denaturing gradient gel electrophoresis (DGGE) of the marker gene ITS and the mcy-gene cluster, and DNA sequencing. We have attempted to calibrate the DGGE-method with a microscopic procedure, using water samples taken in 2011 from four lakes of the Great Mazurian Lakes system. Results Results showed that the classic microscopic method was much more precise and allowed the classification of the majority of cyanobacterial taxa to the species or genus. Using the molecular approach, most of the sequences could only be assigned to a genus or family. The results of DGGE and microscopic analyses overlapped in the detection of the filamentous cyanobacteria. For coccoid cyanobacteria, we only found two taxa using the molecular method, which represented 17% of the total taxa identified using microscopic observations. The DGGE method allowed the identification of two genera of cyanobacteria (Planktothrix and Microcystis) in the studied samples, which have the potential ability to produce toxins from the microcystins group. Conclusions The results confirmed that the molecular approach is useful for the rapid detection and taxonomic distinction of potentially toxic cyanobacteria in lake-water samples, also in very diverse cyanobacterial communities. Such rapid detection is unattainable by other methods. However, with still limited nucleotide sequences deposited in the public databases, this method is currently not sufficient to evaluate the entire taxonomic composition of cyanobacteria in lakes. PMID:24517495

  8. Identification of Conserved and Potentially Regulatory Small RNAs in Heterocystous Cyanobacteria

    PubMed Central

    Brenes-Álvarez, Manuel; Olmedo-Verd, Elvira; Vioque, Agustín; Muro-Pastor, Alicia M.

    2016-01-01

    Small RNAs (sRNAs) are a growing class of non-protein-coding transcripts that participate in the regulation of virtually every aspect of bacterial physiology. Heterocystous cyanobacteria are a group of photosynthetic organisms that exhibit multicellular behavior and developmental alternatives involving specific transcriptomes exclusive of a given physiological condition or even a cell type. In the context of our ongoing effort to understand developmental decisions in these organisms we have undertaken an approach to the global identification of sRNAs. Using differential RNA-Seq we have previously identified transcriptional start sites for the model heterocystous cyanobacterium Nostoc sp. PCC 7120. Here we combine this dataset with a prediction of Rho-independent transcriptional terminators and an analysis of phylogenetic conservation of potential sRNAs among 89 available cyanobacterial genomes. In contrast to predictive genome-wide approaches, the use of an experimental dataset comprising all active transcriptional start sites (differential RNA-Seq) facilitates the identification of bona fide sRNAs. The output of our approach is a dataset of predicted potential sRNAs in Nostoc sp. PCC 7120, with different degrees of phylogenetic conservation across the 89 cyanobacterial genomes analyzed. Previously described sRNAs appear among the predicted sRNAs, demonstrating the performance of the algorithm. In addition, new predicted sRNAs are now identified that can be involved in regulation of different aspects of cyanobacterial physiology, including adaptation to nitrogen stress, the condition that triggers differentiation of heterocysts (specialized nitrogen-fixing cells). Transcription of several predicted sRNAs that appear exclusively in the genomes of heterocystous cyanobacteria is experimentally verified by Northern blot. Cell-specific transcription of one of these sRNAs, NsiR8 (nitrogen stress-induced RNA 8), in developing heterocysts is also demonstrated. PMID

  9. Identification of Conserved and Potentially Regulatory Small RNAs in Heterocystous Cyanobacteria.

    PubMed

    Brenes-Álvarez, Manuel; Olmedo-Verd, Elvira; Vioque, Agustín; Muro-Pastor, Alicia M

    2016-01-01

    Small RNAs (sRNAs) are a growing class of non-protein-coding transcripts that participate in the regulation of virtually every aspect of bacterial physiology. Heterocystous cyanobacteria are a group of photosynthetic organisms that exhibit multicellular behavior and developmental alternatives involving specific transcriptomes exclusive of a given physiological condition or even a cell type. In the context of our ongoing effort to understand developmental decisions in these organisms we have undertaken an approach to the global identification of sRNAs. Using differential RNA-Seq we have previously identified transcriptional start sites for the model heterocystous cyanobacterium Nostoc sp. PCC 7120. Here we combine this dataset with a prediction of Rho-independent transcriptional terminators and an analysis of phylogenetic conservation of potential sRNAs among 89 available cyanobacterial genomes. In contrast to predictive genome-wide approaches, the use of an experimental dataset comprising all active transcriptional start sites (differential RNA-Seq) facilitates the identification of bona fide sRNAs. The output of our approach is a dataset of predicted potential sRNAs in Nostoc sp. PCC 7120, with different degrees of phylogenetic conservation across the 89 cyanobacterial genomes analyzed. Previously described sRNAs appear among the predicted sRNAs, demonstrating the performance of the algorithm. In addition, new predicted sRNAs are now identified that can be involved in regulation of different aspects of cyanobacterial physiology, including adaptation to nitrogen stress, the condition that triggers differentiation of heterocysts (specialized nitrogen-fixing cells). Transcription of several predicted sRNAs that appear exclusively in the genomes of heterocystous cyanobacteria is experimentally verified by Northern blot. Cell-specific transcription of one of these sRNAs, NsiR8 (nitrogen stress-induced RNA 8), in developing heterocysts is also demonstrated.

  10. Identification of Conserved and Potentially Regulatory Small RNAs in Heterocystous Cyanobacteria.

    PubMed

    Brenes-Álvarez, Manuel; Olmedo-Verd, Elvira; Vioque, Agustín; Muro-Pastor, Alicia M

    2016-01-01

    Small RNAs (sRNAs) are a growing class of non-protein-coding transcripts that participate in the regulation of virtually every aspect of bacterial physiology. Heterocystous cyanobacteria are a group of photosynthetic organisms that exhibit multicellular behavior and developmental alternatives involving specific transcriptomes exclusive of a given physiological condition or even a cell type. In the context of our ongoing effort to understand developmental decisions in these organisms we have undertaken an approach to the global identification of sRNAs. Using differential RNA-Seq we have previously identified transcriptional start sites for the model heterocystous cyanobacterium Nostoc sp. PCC 7120. Here we combine this dataset with a prediction of Rho-independent transcriptional terminators and an analysis of phylogenetic conservation of potential sRNAs among 89 available cyanobacterial genomes. In contrast to predictive genome-wide approaches, the use of an experimental dataset comprising all active transcriptional start sites (differential RNA-Seq) facilitates the identification of bona fide sRNAs. The output of our approach is a dataset of predicted potential sRNAs in Nostoc sp. PCC 7120, with different degrees of phylogenetic conservation across the 89 cyanobacterial genomes analyzed. Previously described sRNAs appear among the predicted sRNAs, demonstrating the performance of the algorithm. In addition, new predicted sRNAs are now identified that can be involved in regulation of different aspects of cyanobacterial physiology, including adaptation to nitrogen stress, the condition that triggers differentiation of heterocysts (specialized nitrogen-fixing cells). Transcription of several predicted sRNAs that appear exclusively in the genomes of heterocystous cyanobacteria is experimentally verified by Northern blot. Cell-specific transcription of one of these sRNAs, NsiR8 (nitrogen stress-induced RNA 8), in developing heterocysts is also demonstrated. PMID

  11. Exploring Bioactive Properties of Marine Cyanobacteria Isolated from the Portuguese Coast: High Potential as a Source of Anticancer Compounds

    PubMed Central

    Costa, Margarida; Garcia, Mónica; Costa-Rodrigues, João; Costa, Maria Sofia; Ribeiro, Maria João; Fernandes, Maria Helena; Barros, Piedade; Barreiro, Aldo; Vasconcelos, Vitor; Martins, Rosário

    2013-01-01

    The oceans remain a major source of natural compounds with potential in pharmacology. In particular, during the last few decades, marine cyanobacteria have been in focus as producers of interesting bioactive compounds, especially for the treatment of cancer. In this study, the anticancer potential of extracts from twenty eight marine cyanobacteria strains, belonging to the underexplored picoplanktonic genera, Cyanobium, Synechocystis and Synechococcus, and the filamentous genera, Nodosilinea, Leptolyngbya, Pseudanabaena and Romeria, were assessed in eight human tumor cell lines. First, a crude extract was obtained by dichloromethane:methanol extraction, and from it, three fractions were separated in a Si column chromatography. The crude extract and fractions were tested in eight human cancer cell lines for cell viability/toxicity, accessed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactic dehydrogenase release (LDH) assays. Eight point nine percent of the strains revealed strong cytotoxicity; 17.8% showed moderate cytotoxicity, and 14.3% assays showed low toxicity. The results obtained revealed that the studied genera of marine cyanobacteria are a promising source of novel compounds with potential anticancer activity and highlight the interest in also exploring the smaller filamentous and picoplanktonic genera of cyanobacteria. PMID:24384871

  12. Recognition of an important water quality issue at zoos: prevalence and potential threat of toxic cyanobacteria.

    PubMed

    Doster, Enrique; Chislock, Michael F; Roberts, John F; Kottwitz, Jack J; Wilson, Alan E

    2014-03-01

    Zoo animals may be particularly vulnerable to water sources contaminated with cyanobacterial toxins given their nonvoluntary close association with this resource. However, the prevalence and potential threat of toxic cyanobacteria in this setting are unknown. Several otherwise unexplained yellow-bellied slider (Trachemys scripta scripta) deaths were documented in a zoo moat with recurring blooms of toxic Microcystis aeruginosa. Furthermore, an extremely high and potentially lethal concentration of the hepatotoxin microcystin (166 ng/g) was found in the liver of a necropsied turtle that died in this moat. A subsequent monthly survey of water quality revealed detectable concentrations of microcystin in all moats (0.0001 to 7.5 microg/L), with moats higher than 1 microg/L being significantly higher than the threshold for safe drinking water recommended by the World Health Organization. These results demonstrate that cyanobacterial blooms are an important water quality issue in zoos, and future research is necessary to identify potential associations among water quality, zoo animal health, and moat management strategies.

  13. Potential use of dissolved cyanobacterial DNA for monitoring toxic Microcystis cyanobacteria in filtered water

    NASA Astrophysics Data System (ADS)

    Mbukwa, Elbert A.; Boussiba, Sammy; Wepener, Victor; Leu, Stefan; Yuval, Kaye; Msagati, Titus A. M.; Mamba, Bhekie B.

    Toxic and non-toxic Microcystis sp. are morphologically indistinguishable cyanobacteria that are increasingly posing health problems in fresh water systems by producing odours and/or toxins. Toxic Microcystis sp. produces toxicologically stable water soluble toxic compounds called microcystins (MCs) that have been associated with cases of aquatic life and wildlife poisoning and kills including some cases of human illnesses/deaths around the world. Thus, the need for rapid detection of toxic Microcystis sp. in surface water is imperatively a necessity for early mitigation purposes. Genomic DNA from potentially toxic Microcystis sp. comprises of ten microcystin synthetase (mcy) genes of which six major ones are directly involved in MCs biosynthesis. In Polymerase Chain Reaction (PCR) methodsmcy genes can be amplified from intracellular/extracellular genomic DNA using PCR primers. However, little is known about the limitations of sourcing genomic DNA templates from extracellular DNA dissolved in water. In this work, filtered water (0.45 μM) from a Microcystis infested Dam (South Africa) was re-filtered on 0.22 μM syringe filters followed by genomic DNA isolation and purification from micro-filtrates (9 mL). Six major mcy genes (mcyABCDEG) from the isolated DNA were amplified using newly designed as well as existing primers identified from literature. PCR products were separated by gel electrophoresis and visualized after staining with ethidium bromide. The limitation of using dissolved DNA for amplification of mcy genes was qualitatively studied by establishing the relationship between input DNA concentrations (10.0-0.001 ng/μL) and the formation of respective PCR products. The amplification of mcyA gene using new primers with as little as 0.001 ng/μL of DNA was possible. Other mcy gene sensitivities reached 0.1 ng/μL DNA dilution limits. These results demonstrated that with appropriately optimized PCR conditions the method can provide accurate cost

  14. Cyanobacteria: State Monitoring Programs, Beach Closures, and Potential Human Health Risks

    EPA Science Inventory

    New England is rich in freshwater lakes and ponds, many of which are subject to cyanobacteria (blue-green algae) blooms that can limit recreational use and cause health problems. This study was conducted to better understand the health risks to human and animal populations that a...

  15. Reconstruction and Comparison of the Metabolic Potential of Cyanobacteria Cyanothece sp. ATCC 51142 and Synechocystis sp. PCC 6803

    PubMed Central

    Saha, Rajib; Verseput, Alex T.; Berla, Bertram M.; Mueller, Thomas J.; Pakrasi, Himadri B.; Maranas, Costas D.

    2012-01-01

    Cyanobacteria are an important group of photoautotrophic organisms that can synthesize valuable bio-products by harnessing solar energy. They are endowed with high photosynthetic efficiencies and diverse metabolic capabilities that confer the ability to convert solar energy into a variety of biofuels and their precursors. However, less well studied are the similarities and differences in metabolism of different species of cyanobacteria as they pertain to their suitability as microbial production chassis. Here we assemble, update and compare genome-scale models (iCyt773 and iSyn731) for two phylogenetically related cyanobacterial species, namely Cyanothece sp. ATCC 51142 and Synechocystis sp. PCC 6803. All reactions are elementally and charge balanced and localized into four different intracellular compartments (i.e., periplasm, cytosol, carboxysome and thylakoid lumen) and biomass descriptions are derived based on experimental measurements. Newly added reactions absent in earlier models (266 and 322, respectively) span most metabolic pathways with an emphasis on lipid biosynthesis. All thermodynamically infeasible loops are identified and eliminated from both models. Comparisons of model predictions against gene essentiality data reveal a specificity of 0.94 (94/100) and a sensitivity of 1 (19/19) for the Synechocystis iSyn731 model. The diurnal rhythm of Cyanothece 51142 metabolism is modeled by constructing separate (light/dark) biomass equations and introducing regulatory restrictions over light and dark phases. Specific metabolic pathway differences between the two cyanobacteria alluding to different bio-production potentials are reflected in both models. PMID:23133581

  16. Detection and estimation of potentially toxic cyanobacteria in raw water at the drinking water treatment plant by in vivo fluorescence method.

    PubMed

    Gregor, Jakub; Marsálek, Blahoslav; Sípková, Helena

    2007-01-01

    In vivo fluorescence methods have been accepted as a quick, simple, and useful tool for quantification of phytoplankton organisms. In this paper, we present a case study in which fluorescence methods were employed for the selective detection of potentially toxic cyanobacteria in raw water at the drinking water treatment plant. The occurrence of cyanobacteria in the drinking water reservoir and in raw water was monitored by phycocyanin fluorescence measurements and by standard methods for phytoplankton quantification (cell counts, chlorophyll a). A special attention was paid to the most critical parts of the season -- spring recruitment of cyanobacteria from sediment to water column and autumn bloom collapse. All methods showed similar patterns within the season. Phycocyanin fluorescence was found to be a simple and sensitive indicator of cyanobacteria in water and can serve as a tool that can provide an early warning about the presence of potentially toxic cyanobacterial metabolites in water.

  17. Calcifying Cyanobacteria - The potential of biomineralization for Carbon Capture and Storage

    SciTech Connect

    Jansson, Christer G; Northen, Trent

    2010-03-26

    Employment of cyanobacteria in biomineralization of carbon dioxide by calcium carbonate precipitation offers novel and self-sustaining strategies for point-source carbon capture and sequestration. Although details of this process remain to be elucidated, a carbon-concentrating mechanism, and chemical reactions in exopolysaccharide or proteinaceous surface layers are assumed to be of crucial importance. Cyanobacteria can utilize solar energy through photosynthesis to convert carbon dioxide to recalcitrant calcium carbonate. Calcium can be derived from sources such as gypsum or industrial brine. A better understanding of the biochemical and genetic mechanisms that carry out and regulate cynaobacterial biomineralization should put us in a position where we can further optimize these steps by exploiting the powerful techniques of genetic engineering, directed evolution, and biomimetics.

  18. N-Terminal Protease Gene Phylogeny Reveals the Potential for Novel Cyanobactin Diversity in Cyanobacteria

    PubMed Central

    Martins, Joana; Leão, Pedro N.; Ramos, Vitor; Vasconcelos, Vitor

    2013-01-01

    Cyanobactins are a recently recognized group of ribosomal cyclic peptides produced by cyanobacteria, which have been studied because of their interesting biological activities. Here, we have used a PCR-based approach to detect the N-terminal protease (A) gene from cyanobactin synthetase gene clusters, in a set of diverse cyanobacteria from our culture collection (Laboratory of Ecotoxicology, Genomics and Evolution (LEGE) CC). Homologues of this gene were found in Microcystis and Rivularia strains, and for the first time in Cuspidothrix, Phormidium and Sphaerospermopsis strains. Phylogenetic relationships inferred from available A-gene sequences, including those obtained in this work, revealed two new groups of phylotypes, harboring Phormidium, Sphaerospermopsis and Rivularia LEGE isolates. Thus, this study shows that, using underexplored cyanobacterial strains, it is still possible to expand the known genetic diversity of genes involved in cyanobactin biosynthesis. PMID:24351973

  19. Calcifying cyanobacteria--the potential of biomineralization for carbon capture and storage.

    PubMed

    Jansson, Christer; Northen, Trent

    2010-06-01

    Employment of cyanobacteria in biomineralization of carbon dioxide by calcium carbonate precipitation offers novel and self-sustaining strategies for point-source carbon capture and sequestration. Although details of this process remain to be elucidated, a carbon-concentrating mechanism, and chemical reactions in exopolysaccharide or proteinaceous surface layers are assumed to be of crucial importance. Cyanobacteria can utilize solar energy through photosynthesis to convert carbon dioxide to recalcitrant calcium carbonate. Calcium can be derived from sources such as gypsum or industrial brine. A better understanding of the biochemical and genetic mechanisms that carry out and regulate cynaobacterial biomineralization should put us in a position where we can further optimize these steps by exploiting the powerful techniques of genetic engineering, directed evolution, and biomimetics.

  20. Spatiotemporal Variations in Microcystin Concentrations and in the Proportions of Microcystin-Producing Cells in Several Microcystis aeruginosa Populations▿

    PubMed Central

    Sabart, M.; Pobel, D.; Briand, E.; Combourieu, B.; Salençon, M. J.; Humbert, J. F.; Latour, D.

    2010-01-01

    With the aim of explaining the variations in microcystin (MC) concentrations during cyanobacterial blooms, we studied several Microcystis aeruginosa populations blooming in different freshwater ecosystems located in the same geographical area. As assessed by real-time PCR, it appeared that the potentially MC-producing cells (mcyB+) were predominant (70 to 100%) in all of these M. aeruginosa populations, with the exception of one population in which non-MC-producing cells always dominated. Apart from the population in the Grangent Reservoir, we found that the proportions of potentially MC-producing and non-MC-producing cells varied little over time, which was consistent with the fact that according to a previous study of the same populations, the intergenic transcribed spacer (ITS) genotype composition did not change (38). In the Grangent Reservoir, the MC-RR variant was the dominant microcystin variant throughout the bloom season, despite changes in the ITS composition and in the proportions of mcyB+ cells. Finally, the variations in total MC concentrations (0.3 to 15 μg liter−1) and in the MC cellular quotas (0.01 to 3.4 pg cell−1) were high both between and within sites, and no correlation was found between the MC concentrations and the proportion of mcyB+ cells. All of these findings demonstrate that very different results can be found for the proportions of potentially MC-producing and non-MC-producing cells and MC concentrations, even in M. aeruginosa populations living in more or less connected ecosystems, demonstrating the importance of the effect of very local environmental conditions on these parameters and also the difficulty of predicting the potential toxicity of Microcystis blooms. PMID:20511422

  1. Cosmopolitan Cyanobacteria

    ERIC Educational Resources Information Center

    Furey, Paula C.

    2003-01-01

    In this article, the author presents a poem on the distribution and adaptation of blue-green algae (Cyanobacteria). The poem describes some of the diverse habitats of cyanobacteria including examples from extreme and unique environments such as hot springs, and polar bear hair. The poem also describes some of the adaptations of cyanobacteria…

  2. Monitoring of potentially toxic cyanobacteria using an online multi-probe in drinking water sources.

    PubMed

    Zamyadi, A; McQuaid, N; Prévost, M; Dorner, S

    2012-02-01

    Toxic cyanobacteria threaten the water quality of drinking water sources across the globe. Two such water bodies in Canada (a reservoir on the Yamaska River and a bay of Lake Champlain in Québec) were monitored using a YSI 6600 V2-4 (YSI, Yellow Springs, Ohio, USA) submersible multi-probe measuring in vivo phycocyanin (PC) and chlorophyll-a (Chl-a) fluorescence, pH, dissolved oxygen, conductivity, temperature, and turbidity in parallel. The linearity of the in vivo fluorescence PC and Chl-a probe measurements were validated in the laboratory with Microcystis aeruginosa (r(2) = 0.96 and r(2) = 0.82 respectively). Under environmental conditions, in vivo PC fluorescence was strongly correlated with extracted PC (r = 0.79) while in vivo Chl-a fluorescence had a weaker relationship with extracted Chl-a (r = 0.23). Multiple regression analysis revealed significant correlations between extracted Chl-a, extracted PC and cyanobacterial biovolume and in vivo fluorescence parameters measured by the sensors (i.e. turbidity and pH). This information will help water authorities select the in vivo parameters that are the most useful indicators for monitoring cyanobacteria. Despite highly toxic cyanobacterial bloom development 10 m from the drinking water treatment plant's (DWTP) intake on several sampling dates, low in vivo PC fluorescence, cyanobacterial biovolume, and microcystin concentrations were detected in the plant's untreated water. The reservoir's hydrodynamics appear to have prevented the transport of toxins and cells into the DWTP which would have deteriorated the water quality. The multi-probe readings and toxin analyses provided critical evidence that the DWTP's untreated water was unaffected by the toxic cyanobacterial blooms present in its source water. PMID:22159157

  3. Monitoring of potentially toxic cyanobacteria using an online multi-probe in drinking water sources.

    PubMed

    Zamyadi, A; McQuaid, N; Prévost, M; Dorner, S

    2012-02-01

    Toxic cyanobacteria threaten the water quality of drinking water sources across the globe. Two such water bodies in Canada (a reservoir on the Yamaska River and a bay of Lake Champlain in Québec) were monitored using a YSI 6600 V2-4 (YSI, Yellow Springs, Ohio, USA) submersible multi-probe measuring in vivo phycocyanin (PC) and chlorophyll-a (Chl-a) fluorescence, pH, dissolved oxygen, conductivity, temperature, and turbidity in parallel. The linearity of the in vivo fluorescence PC and Chl-a probe measurements were validated in the laboratory with Microcystis aeruginosa (r(2) = 0.96 and r(2) = 0.82 respectively). Under environmental conditions, in vivo PC fluorescence was strongly correlated with extracted PC (r = 0.79) while in vivo Chl-a fluorescence had a weaker relationship with extracted Chl-a (r = 0.23). Multiple regression analysis revealed significant correlations between extracted Chl-a, extracted PC and cyanobacterial biovolume and in vivo fluorescence parameters measured by the sensors (i.e. turbidity and pH). This information will help water authorities select the in vivo parameters that are the most useful indicators for monitoring cyanobacteria. Despite highly toxic cyanobacterial bloom development 10 m from the drinking water treatment plant's (DWTP) intake on several sampling dates, low in vivo PC fluorescence, cyanobacterial biovolume, and microcystin concentrations were detected in the plant's untreated water. The reservoir's hydrodynamics appear to have prevented the transport of toxins and cells into the DWTP which would have deteriorated the water quality. The multi-probe readings and toxin analyses provided critical evidence that the DWTP's untreated water was unaffected by the toxic cyanobacterial blooms present in its source water.

  4. Elucidation of taste- and odor-producing bacteria and toxigenic cyanobacteria in a Midwestern drinking water supply reservoir by shotgun metagenomics analysis

    USGS Publications Warehouse

    Otten, Timothy; Graham, Jennifer; Harris, Theodore D.; Dreher, Theo

    2016-01-01

    While commonplace in clinical settings, DNA-based assays for identification or enumeration of drinking water pathogens and other biological contaminants remain widely unadopted by the monitoring community. In this study, shotgun metagenomics was used to identify taste-and-odor producers and toxin-producing cyanobacteria over a 2-year period in a drinking water reservoir. The sequencing data implicated several cyanobacteria, including Anabaena spp.,Microcystis spp., and an unresolved member of the order Oscillatoriales as the likely principal producers of geosmin, microcystin, and 2-methylisoborneol (MIB), respectively. To further demonstrate this, quantitative PCR (qPCR) assays targeting geosmin-producing Anabaena and microcystin-producing Microcystis were utilized, and these data were fitted using generalized linear models and compared with routine monitoring data, including microscopic cell counts, sonde-based physicochemical analyses, and assays of all inorganic and organic nitrogen and phosphorus forms and fractions. The qPCR assays explained the greatest variation in observed geosmin (adjusted R2 = 0.71) and microcystin (adjusted R2 = 0.84) concentrations over the study period, highlighting their potential for routine monitoring applications. The origin of the monoterpene cyclase required for MIB biosynthesis was putatively linked to a periphytic cyanobacterial mat attached to the concrete drinking water inflow structure. We conclude that shotgun metagenomics can be used to identify microbial agents involved in water quality deterioration and to guide PCR assay selection or design for routine monitoring purposes. Finally, we offer estimates of microbial diversity and metagenomic coverage of our data sets for reference to others wishing to apply shotgun metagenomics to other lacustrine systems.

  5. Cyanobacteria toxins in the Salton Sea

    PubMed Central

    Carmichael, Wayne W; Li, RenHui

    2006-01-01

    laboratory strain of Synechococcus was identified by PCR as being closest to known marine forms of this genus. Analyses of affected grebe livers found microcystins at levels that may account for some of the acute mortalities. Conclusion The production of microcystins by a marine Synechococcus indicates that microcystins may be a more common occurrence in marine environments – a finding not recognized before this work. Further research should be done to define the distribution of microcystin producing marine cyanobacteria and to determine exposure/response effects of microcystins and possibly other cyanotoxins in the Salton Sea. Future efforts to reduce avian mortalities and remediate the Salton Sea should evaluate vectors by which microcystins enter avian species and ways to control and mitigate toxic cyanobacteria waterblooms at the Salton Sea. PMID:16623944

  6. MIB-producing cyanobacteria (Planktothrix sp.) in a drinking water reservoir: distribution and odor producing potential.

    PubMed

    Su, Ming; Yu, Jianwei; Zhang, Junzhi; Chen, Hui; An, Wei; Vogt, Rolf D; Andersen, Tom; Jia, Dongmin; Wang, Jingshi; Yang, Min

    2015-01-01

    The production of odorant 2-methylisoborneol (MIB) in water bodies by Planktothrix sp. have not been understood very well. Through a four-year investigation in Miyun Reservoir, a huge mesotrophic drinking water reservoir known to have the MIB episodes, we found that the Planktothrix sp. bloomed during September and October causing the high levels of MIB in the reservoir. The concentration of MIB and the biomass of MIB-producing cyanobacteria Planktothrix were measured (n = 887) at different sites and depths during different seasons. The results indicated that the shallow region of the reservoir is the major habitat for Planktothrix sp. due to that the light is able to penetrate down to the relatively high concentrations of nutrients close to the sediments. Quantile regression analysis between Planktothrix biomass and MIB concentration shows that the risk of MIB exceeding the odor threshold (15 ng L⁻¹) in water was as high as 90% when the Planktothrix density was more than 4.0 × 10⁵ cells L⁻¹, while the risk was reduced to 10% when the Planktothrix density remained below 1.6 × 10⁴ cells L⁻¹. This study will improve the understanding of the environmental behaviors of Planktothrix sp., and can provide useful information for better management of drinking water lakes/reservoirs experiencing the taste and odor (T&O) problems caused by deep living cyanobacterial species.

  7. Nitrogen Fixation by Thermophilic Blue-Green Algae (Cyanobacteria): Temperature Characteristics and Potential Use in Biophotolysis

    PubMed Central

    Miyamoto, Kazuhisa; Hallenbeck, Patrick C.; Benemann, John R.

    1979-01-01

    Thermophilic, nitrogen-fixing, blue-green algae (cyanobacteria) were investigated for use in biophotolysis. Three strains of Mastigocladus laminosus were tested and were found to be equally effective in biophotolysis as judged by nitrogenase activity. The alga, M. laminosus NZ-86-m, which was chosen for further study, grew well in the temperature range from 35 to 50°C, with optimum growth at 45°C, at which temperature acetylene reduction activity was also greatest. The maximum tolerable temperature was 55°C. Acetylene reduction activity was saturated at a light intensity of 1 × 104 ergs cm−2 s−1. Atmospheric oxygen tension was found to be slightly inhibitory to acetylene reduction of both slowly growing and exponentially growing cultures. Nonsterile continuous cultures, which were conducted to test problems of culture maintenance, could be operated for 2 months without any significant decrease in nitrogenase activity or contamination by other algae. Nitrogen-starved cultures of M. laminosus NZ-86-m produced hydrogen at comparable rates to Anabaena cylindrica. The conversion efficiency of light to hydrogen energy at maximum rates of hydrogen production was 2.7%. PMID:16345353

  8. Two strictly polyphosphate-dependent gluco(manno)kinases from diazotrophic Cyanobacteria with potential to phosphorylate hexoses from polyphosphates.

    PubMed

    Albi, Tomás; Serrano, Aurelio

    2015-05-01

    The single-copy genes encoding putative polyphosphate-glucose phosphotransferases (PPGK, EC 2.7.1.63) from two nitrogen-fixing Cyanobacteria, Nostoc sp. PCC7120 and Nostoc punctiforme PCC73102, were cloned and functionally characterized. In contrast to their actinobacterial counterparts, the cyanobacterial PPGKs have shown the ability to phosphorylate glucose using strictly inorganic polyphosphates (polyP) as phosphoryl donors. This has proven to be an economically attractive reagent in contrast to the more costly ATP. Cyanobacterial PPGKs had a higher affinity for medium-long-sized polyP (greater than ten phosphoryl residues). Thus, longer polyP resulted in higher catalytic efficiency. Also in contrast to most their homologs in Actinobacteria, both cyanobacterial PPGKs exhibited a modest but significant polyP-mannokinase activity as well. Specific activities were in the range of 180-230 and 2-3 μmol min(-1) mg(-1) with glucose and mannose as substrates, respectively. No polyP-fructokinase activity was detected. Cyanobacterial PPGKs required a divalent metal cofactor and exhibited alkaline pH optima (approx. 9.0) and a remarkable thermostability (optimum temperature, 45 °C). The preference for Mg(2+) was noted with an affinity constant of 1.3 mM. Both recombinant PPGKs are homodimers with a subunit molecular mass of ca. 27 kDa. Based on database searches and experimental data from Southern blots and activity assays, closely related PPGK homologs appear to be widespread among unicellular and filamentous mostly nitrogen-fixing Cyanobacteria. Overall, these findings indicate that polyP may be metabolized in these photosynthetic prokaryotes to yield glucose (or mannose) 6-phosphate. They also provide evidence for a novel group-specific subfamily of strictly polyP-dependent gluco(manno)kinases with ancestral features and high biotechnological potential, capable of efficiently using polyP as an alternative and cheap source of energy-rich phosphate instead of costly ATP

  9. Two strictly polyphosphate-dependent gluco(manno)kinases from diazotrophic Cyanobacteria with potential to phosphorylate hexoses from polyphosphates.

    PubMed

    Albi, Tomás; Serrano, Aurelio

    2015-05-01

    The single-copy genes encoding putative polyphosphate-glucose phosphotransferases (PPGK, EC 2.7.1.63) from two nitrogen-fixing Cyanobacteria, Nostoc sp. PCC7120 and Nostoc punctiforme PCC73102, were cloned and functionally characterized. In contrast to their actinobacterial counterparts, the cyanobacterial PPGKs have shown the ability to phosphorylate glucose using strictly inorganic polyphosphates (polyP) as phosphoryl donors. This has proven to be an economically attractive reagent in contrast to the more costly ATP. Cyanobacterial PPGKs had a higher affinity for medium-long-sized polyP (greater than ten phosphoryl residues). Thus, longer polyP resulted in higher catalytic efficiency. Also in contrast to most their homologs in Actinobacteria, both cyanobacterial PPGKs exhibited a modest but significant polyP-mannokinase activity as well. Specific activities were in the range of 180-230 and 2-3 μmol min(-1) mg(-1) with glucose and mannose as substrates, respectively. No polyP-fructokinase activity was detected. Cyanobacterial PPGKs required a divalent metal cofactor and exhibited alkaline pH optima (approx. 9.0) and a remarkable thermostability (optimum temperature, 45 °C). The preference for Mg(2+) was noted with an affinity constant of 1.3 mM. Both recombinant PPGKs are homodimers with a subunit molecular mass of ca. 27 kDa. Based on database searches and experimental data from Southern blots and activity assays, closely related PPGK homologs appear to be widespread among unicellular and filamentous mostly nitrogen-fixing Cyanobacteria. Overall, these findings indicate that polyP may be metabolized in these photosynthetic prokaryotes to yield glucose (or mannose) 6-phosphate. They also provide evidence for a novel group-specific subfamily of strictly polyP-dependent gluco(manno)kinases with ancestral features and high biotechnological potential, capable of efficiently using polyP as an alternative and cheap source of energy-rich phosphate instead of costly ATP

  10. Application of a spectrofluorimetric tool (bbe BenthoTorch) for monitoring potentially toxic benthic cyanobacteria in rivers.

    PubMed

    Echenique-Subiabre, Isidora; Dalle, Caroline; Duval, Charlotte; Heath, Mark W; Couté, Alain; Wood, Susanna A; Humbert, Jean-François; Quiblier, Catherine

    2016-09-15

    Over the last decade reports of animal poisoning following accidental consumption of neurotoxin-producing benthic cyanobacteria (mainly Phormidium spp.) have increased. There is a need for rapid and cost-effective tools to survey benthic cyanobacteria. In this study we assessed the performance of the BenthoTorch, a fluorometric probe that provides in situ estimations of cyanobacteria, diatoms and green algae biomass in biofilms. Biofilms (n = 288) were analysed from two rivers in France and eight in New Zealand. Correlations between chlorophyll-a measured using the BenthoTorch and spectrophotometry were higher for thin (<2 mm) compared to thick (>2 mm) biofilms (r(2) = 0.58 and 0.27 respectively; p < 0.001). When cyanobacteria represented less than 50% of the total biomass (based on biovolumes), microscopic and BenthoTorch compositional estimations were significantly correlated (r(2) = 0.53, p < 0.001). Conversely, there was no correlation when cyanobacteria exceeded 50% of the total biomass. Under this scenario diatoms were overestimated. Our results suggest that the observed biases occur because the BenthoTorch only measures the upper biofilm layer and it underestimates the biomass of phycoerythrin-containing cyanobacteria. To improve the performance of this sensor and render it a useful tool for a rapid evaluation of benthic cyanobacterial biomass in rivers, we propose that: (i) the algorithms based on the LEDs responses currently available on this tool need revision, (ii) new excitation wavelengths should be included that allow the fingerprints of phycoerythrin-containing cyanobacteria to be discriminated, and (iii) a sensor that penetrates the biofilms is needed to obtain more accurate estimates of cyanobacterial biomass. PMID:27286469

  11. Presence of Potential Toxin-Producing Cyanobacteria in an Oligo-Mesotrophic Lake in Baltic Lake District, Germany: An Ecological, Genetic and Toxicological Survey

    PubMed Central

    Dadheech, Pawan K.; Selmeczy, Géza B.; Vasas, Gábor; Padisák, Judit; Arp, Wolfgang; Tapolczai, Kálmán; Casper, Peter; Krienitz, Lothar

    2014-01-01

    Massive developments of potentially toxic cyanobacteria in Lake Stechlin, an oligo-mesotrophic lake in the Baltic Lake District of Germany raised concerns about toxic contamination of these important ecosystems. Field samples in the phase of mass developments of cyanobacteria were used for genetic and toxicological analyses. Microcystins and microcystin genes were detected in field samples of the lake for the first time. However, the toxins were not produced by the dominant taxa (Dolichospermum circinale and Aphanizomenon flos-aquae) but by taxa, which were present only in low biomass in the samples (Microcystis cf. aeruginosa and Planktothrix rubescens). The phytoplankton successions during the study period revealed an increase of cyanobacterial populations. The findings contribute to the changes that have been investigated in Lake Stechlin since the mid-1990s. The possible reasons behind these developments may be climate change, special weather conditions and an increased nutrient pool. PMID:25268981

  12. Environmental influence on cyanobacteria abundance and microcystin toxin production in a shallow temperate lake.

    PubMed

    Lee, Tammy A; Rollwagen-Bollens, Gretchen; Bollens, Stephen M; Faber-Hammond, Joshua J

    2015-04-01

    The increasing frequency of harmful cyanobacterial blooms in freshwater systems is a commonly recognized problem due to detrimental effects on water quality. Vancouver Lake, a shallow, tidally influenced lake in the flood plain of the Columbia River within the city of Vancouver, WA, USA, has experienced numerous summertime cyanobacterial blooms, dominated by Aphanizomenon sp. and Anabaena sp. Cyanobacteria abundance and toxin (microcystin) levels have been monitored in this popular urban lake for several years; however, no previous studies have identified which cyanobacteria species produce toxins, nor analyzed how changes in environmental variables contribute to the fluctuations in toxic cyanobacteria populations. We used a suite of molecular techniques to analyze water samples from Vancouver Lake over two summer bloom cycles (2009 and 2010). Both intracellular and extracellular microcystin concentrations were measured using an ELISA kit. Intracellular microcystin concentrations exceeded WHO guidelines for recreational waters several times throughout the sampling period. PCR results demonstrated that Microcystis sp. was the sole microcystin-producing cyanobacteria species present in Vancouver Lake, although Microcystis sp. was rarely detected in microscopical counts. qPCR results indicated that the majority of the Microcystis sp. population contained the toxin-producing gene (mcyE), although Microcystis sp. abundance rarely exceeded 1 percent of overall cyanobacteria abundance. Non-metric multidimensional scaling (NMDS) revealed that PO4-P was the main environmental variable influencing the abundance of toxic and non-toxic cyanobacteria, as well as intracellular microcystin concentrations. Our study underscores the importance of using molecular genetic techniques, in addition to traditional microscopy, to assess the importance of less conspicuous species in the dynamics of harmful algal blooms.

  13. EPS composition and calcification potential of tufa-dominating cyanobacteria investigated by Scanning Transmission X-ray Microscopy (STXM) and Laser Scanning Microscopy (LSM)

    NASA Astrophysics Data System (ADS)

    Zippel, Barbara; Dynes, James J.; Obst, Martin; Lawrence, John R.; Neu, Thomas R.

    2010-05-01

    Tufa deposits in freshwater habitats are the result of calcium carbonate precipitation within interfacial microbial ecosystems. Calcite precipitation is influenced by the saturation index and the occurrence of extracellular polymeric substances (EPS) which are produced by a variety of microorganisms. In theory, the first important step of biologically induced calcification processes is the adsorption of calcium ions by extracellular polymeric substances (EPS) produced by cyanobacteria. In the present study we take advantage of Laser Scanning Microscopy (LSM) and combine it with Synchrotron imaging using Scanning Transmission X-ray Microscopy (STXM). STXM represents a technique that allows simultaneous analysis of inorganic and organic constituents as a scale of 50 nm. By means of STXM it is possible to differentiate between calcium carbonate phases at the Ca L-edge. Furthermore, STXM has also been used at the C K-edge to map the major biomolecules (proteins, lipids, and polysaccharides). The purpose of this study is to find out if there are differences in calcium adsorption depending on specific composition of the EPS produced by filamentous cyanobacteria isolated from a German hard water creek (Westerhöfer Bach, Harz Mountains). The goal was to elucidate the potential of biofilms constituents, including microbial cell surfaces as well as extracellular polymeric substances, in triggering the formation of calcium carbonate in tufa systems. For this purpose three filamentous cyanobacteria (Pseudanabaena sp., Leptolyngbya sp. and Nostoc sp.) were cultivated in creek-adapted as well as standard media (BG11) on polycarbonate slides. In situ EPS composition was detected by means of fluorescence lectin-binding approach (FLBA) using 23 commercially available lectins with different specificities for mono- and disaccharides and amino sugars. For CaCO3 nucleation experiments cyanobacterial biofilms grown on polycarbonate slides were deposited in NaHCO3/CaCl2 solutions

  14. *CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Cyanobacteria, or blue-green algae, are naturally-occurring contaminants of surface waters worldwide. These photosynthesizing prokaryotes thrive in warm, shallow, nutrient-rich waters. Many produce potent toxins as secondary metabolites. Cyanobacteria toxins have been document...

  15. Calcification and silicification: fossilization potential of cyanobacteria from stromatolites of Niuafo'ou's Caldera Lakes (Tonga) and implications for the early fossil record.

    PubMed

    Kremer, Barbara; Kazmierczak, Józef; Lukomska-Kowalczyk, Maja; Kempe, Stephan

    2012-06-01

    Calcification and silicification processes of cyanobacterial mats that form stromatolites in two caldera lakes of Niuafo'ou Island (Vai Lahi and Vai Si'i) were evaluated, and their importance as analogues for interpreting the early fossil record are discussed. It has been shown that the potential for morphological preservation of Niuafo'ou cyanobacteria is highly dependent on the timing and type of mineral phase involved in the fossilization process. Four main modes of mineralization of cyanobacteria organic parts have been recognized: (i) primary early postmortem calcification by aragonite nanograins that transform quickly into larger needle-like crystals and almost totally destroy the cellular structures, (ii) primary early postmortem silicification of almost intact cyanobacterial cells that leave a record of spectacularly well-preserved cellular structures, (iii) replacement by silica of primary aragonite that has already recrystallized and obliterated the cellular structures, (iv) occasional replacement of primary aragonite precipitated in the mucopolysaccharide sheaths and extracellular polymeric substances by Al-Mg-Fe silicates. These observations suggest that the extremely scarce earliest fossil record may, in part, be the result of (a) secondary replacement by silica of primary carbonate minerals (aragonite, calcite, siderite), which, due to recrystallization, had already annihilated the cellular morphology of the mineralized microbiota or (b) relatively late primary silicification of already highly degraded and no longer morphologically identifiable microbial remains.

  16. Calcification and Silicification: Fossilization Potential of Cyanobacteria from Stromatolites of Niuafo‘ou's Caldera Lakes (Tonga) and Implications for the Early Fossil Record

    PubMed Central

    Kazmierczak, Józef; Łukomska-Kowalczyk, Maja; Kempe, Stephan

    2012-01-01

    Abstract Calcification and silicification processes of cyanobacterial mats that form stromatolites in two caldera lakes of Niuafo‘ou Island (Vai Lahi and Vai Si‘i) were evaluated, and their importance as analogues for interpreting the early fossil record are discussed. It has been shown that the potential for morphological preservation of Niuafo‘ou cyanobacteria is highly dependent on the timing and type of mineral phase involved in the fossilization process. Four main modes of mineralization of cyanobacteria organic parts have been recognized: (i) primary early postmortem calcification by aragonite nanograins that transform quickly into larger needle-like crystals and almost totally destroy the cellular structures, (ii) primary early postmortem silicification of almost intact cyanobacterial cells that leave a record of spectacularly well-preserved cellular structures, (iii) replacement by silica of primary aragonite that has already recrystallized and obliterated the cellular structures, (iv) occasional replacement of primary aragonite precipitated in the mucopolysaccharide sheaths and extracellular polymeric substances by Al-Mg-Fe silicates. These observations suggest that the extremely scarce earliest fossil record may, in part, be the result of (a) secondary replacement by silica of primary carbonate minerals (aragonite, calcite, siderite), which, due to recrystallization, had already annihilated the cellular morphology of the mineralized microbiota or (b) relatively late primary silicification of already highly degraded and no longer morphologically identifiable microbial remains. Key Words: Stromatolites—Cyanobacteria—Calcification—Silicification—Niuafo‘ou (Tonga)—Archean. Astrobiology 12, 535–548. PMID:22794297

  17. Engineering cyanobacteria as photosynthetic feedstock factories.

    PubMed

    Hays, Stephanie G; Ducat, Daniel C

    2015-03-01

    Carbohydrate feedstocks are at the root of bioindustrial production and are needed in greater quantities than ever due to increased prioritization of renewable fuels with reduced carbon footprints. Cyanobacteria possess a number of features that make them well suited as an alternative feedstock crop in comparison to traditional terrestrial plant species. Recent advances in genetic engineering, as well as promising preliminary investigations of cyanobacteria in a number of distinct production regimes have illustrated the potential of these aquatic phototrophs as biosynthetic chassis. Further improvements in strain productivities and design, along with enhanced understanding of photosynthetic metabolism in cyanobacteria may pave the way to translate cyanobacterial theoretical potential into realized application.

  18. Evolutionary significance of osmoregulatory mechanisms in cyanobacteria

    NASA Technical Reports Server (NTRS)

    Yopp, J. H.; Pavlicek, J. H.; Sibley, M. H.

    1986-01-01

    Physiological processes of all life forms on this planet are intrinsically related to their intracellular water potential. The overall goal was the elucidation of the mechanism(s) whereby the first oxygenic phtoautotrophs (the cyanobacteria) adjust their water potential to that of a changing external water potential (that is, osmoregulate). Osmoregulation is achieved by intracellular adjustment of inorganic and/or organic solutes (osmolytes) involving specific biochemical mechanisms. Structural and biochemical evolution within the cyanobacteria is believed completed (and fixed in present day forms) by the end of the Precambrain eon. Therefore, research using cyanobacteria of all three structural types (unicellular, filamentous, and branched), each grown in the photoautotrophic (PA), photoheterotrophic (PG), and chemotrophic (CH) modes of nutrition, should provide insight into the origin and evolution of the photosynthetically related osmoregulatory mechanisms of eukaryotic organisms. The chloroplasts of these organisms are phylogenetically related to the cyanobacteria.

  19. CYANOBACTERIA AND THEIR TOXINS.

    EPA Science Inventory

    Science Questions

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

  20. CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Science Questions

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

  1. Engineering cyanobacteria for fuels and chemicals production.

    PubMed

    Zhou, Jie; Li, Yin

    2010-03-01

    The world's energy and global warming crises call for sustainable, renewable, carbon-neutral alternatives to replace fossil fuel resources. Currently, most biofuels are produced from agricultural crops and residues, which lead to concerns about food security and land shortage. Compared to the current biofuel production system, cyanobacteria, as autotrophic prokaryotes, do not require arable land and can grow to high densities by efficiently using solar energy, CO(2), water, and inorganic nutrients. Moreover, powerful genetic techniques of cyanobacteria have been developed. For these reasons, cyanobacteria, which carry out oxygenic photosynthesis, are attractive hosts for production of fuels and chemicals. Recently, several chemicals including ethanol, isobutanol and isoprene have been produced by engineered cyanobacteria directly using solar energy, CO(2), and water. Cyanobacterium is therefore a potential novel cell factory for fuels and chemicals production to address global energy security and climate change issues.

  2. Engineering cyanobacteria for fuels and chemicals production.

    PubMed

    Zhou, Jie; Li, Yin

    2010-03-01

    The world's energy and global warming crises call for sustainable, renewable, carbon-neutral alternatives to replace fossil fuel resources. Currently, most biofuels are produced from agricultural crops and residues, which lead to concerns about food security and land shortage. Compared to the current biofuel production system, cyanobacteria, as autotrophic prokaryotes, do not require arable land and can grow to high densities by efficiently using solar energy, CO(2), water, and inorganic nutrients. Moreover, powerful genetic techniques of cyanobacteria have been developed. For these reasons, cyanobacteria, which carry out oxygenic photosynthesis, are attractive hosts for production of fuels and chemicals. Recently, several chemicals including ethanol, isobutanol and isoprene have been produced by engineered cyanobacteria directly using solar energy, CO(2), and water. Cyanobacterium is therefore a potential novel cell factory for fuels and chemicals production to address global energy security and climate change issues. PMID:21203966

  3. Genetically Engineered Cyanobacteria

    NASA Technical Reports Server (NTRS)

    Zhou, Ruanbao (Inventor); Gibbons, William (Inventor)

    2015-01-01

    The disclosed embodiments provide cyanobacteria spp. that have been genetically engineered to have increased production of carbon-based products of interest. These genetically engineered hosts efficiently convert carbon dioxide and light into carbon-based products of interest such as long chained hydrocarbons. Several constructs containing polynucleotides encoding enzymes active in the metabolic pathways of cyanobacteria are disclosed. In many instances, the cyanobacteria strains have been further genetically modified to optimize production of the carbon-based products of interest. The optimization includes both up-regulation and down-regulation of particular genes.

  4. Monitoring indicators of harmful cyanobacteria in Texas

    USGS Publications Warehouse

    Kiesling, Richard L.; Gary, Robin H.; Gary, Marcus O.

    2008-01-01

    Harmful algal blooms can occur when certain types of microscopic algae grow quickly in water, forming visible patches that might harm the health of the environment, plants, or animals. In freshwater, species of Cyanobacteria (also known as bluegreen algae) are the dominant group of harmful, bloom-forming algae. When Cyanobacteria form a harmful algal bloom, potential impairments include restricted recreational activities because of algal scums or algal mats, potential loss of public water supply because of taste and odor compounds (for example, geosmin), and the production of toxins (for example, microcystin) in amounts capable of threatening human health and wildlife.

  5. Breakthrough of cyanobacteria in bank filtration.

    PubMed

    Pazouki, Pirooz; Prévost, Michèle; McQuaid, Natasha; Barbeau, Benoit; de Boutray, Marie-Laure; Zamyadi, Arash; Dorner, Sarah

    2016-10-01

    The removal of cyanobacteria cells in well water following bank filtration was investigated from a source water consisting of two artificial lakes (A and B). Phycocyanin probes used to monitor cyanobacteria in the source and in filtered well water showed an increase of fluorescence values demonstrating a progressive seasonal growth of cyanobacteria in the source water that were correlated with cyanobacterial biovolumes from taxonomic counts (r = 0.59, p < 0.00001). A strong correlation was observed between the cyanobacterial concentrations in the lake water and in the well water as measured by the phycocyanin probe (p < 0.001, 0.73 ≤ r(2) ≤ 0.94). Log removals from bank filtration estimated from taxonomic counts ranged from 0.96 ± (0.5) and varied according to the species of cyanobacteria. Of cyanobacteria that passed through bank filtration, smaller cells were significantly more frequent in well water samples (p < 0.05) than larger cells. Travel times from the lakes to the wells were estimated as 2 days for Lake B and 10 days for Lake A. Cyanobacterial species in the wells were most closely related to species found in Lake B. Thus, a travel time of less than 1 week permitted the breakthrough of cyanobacteria to wells. Winter samples demonstrated that cyanobacteria accumulate within bank filters, leading to continued passage of cells beyond the bloom season. Although no concentrations of total microcystin-LR were above detection limits in filtered well water, there is concern that cyanobacterial cells that reach the wells have the potential to contain intracellular toxins.

  6. Breakthrough of cyanobacteria in bank filtration.

    PubMed

    Pazouki, Pirooz; Prévost, Michèle; McQuaid, Natasha; Barbeau, Benoit; de Boutray, Marie-Laure; Zamyadi, Arash; Dorner, Sarah

    2016-10-01

    The removal of cyanobacteria cells in well water following bank filtration was investigated from a source water consisting of two artificial lakes (A and B). Phycocyanin probes used to monitor cyanobacteria in the source and in filtered well water showed an increase of fluorescence values demonstrating a progressive seasonal growth of cyanobacteria in the source water that were correlated with cyanobacterial biovolumes from taxonomic counts (r = 0.59, p < 0.00001). A strong correlation was observed between the cyanobacterial concentrations in the lake water and in the well water as measured by the phycocyanin probe (p < 0.001, 0.73 ≤ r(2) ≤ 0.94). Log removals from bank filtration estimated from taxonomic counts ranged from 0.96 ± (0.5) and varied according to the species of cyanobacteria. Of cyanobacteria that passed through bank filtration, smaller cells were significantly more frequent in well water samples (p < 0.05) than larger cells. Travel times from the lakes to the wells were estimated as 2 days for Lake B and 10 days for Lake A. Cyanobacterial species in the wells were most closely related to species found in Lake B. Thus, a travel time of less than 1 week permitted the breakthrough of cyanobacteria to wells. Winter samples demonstrated that cyanobacteria accumulate within bank filters, leading to continued passage of cells beyond the bloom season. Although no concentrations of total microcystin-LR were above detection limits in filtered well water, there is concern that cyanobacterial cells that reach the wells have the potential to contain intracellular toxins. PMID:27343842

  7. Membrane Systems in Cyanobacteria

    SciTech Connect

    Liberton, Michelle L.; Pakrasi, Himadri B.

    2008-01-01

    Cyanobacteria are photosynthetic prokaryotes with highly differentiated membrane systems. In addition to a Gram-negative-type cell envelope with plasma membrane and outer membrane separated by a periplasmic space, cyanobacteria have an internal system of thylakoid membranes where the fully functional electron transfer chains of photosynthesis and respiration reside. The presence of different membrane systems lends these cells a unique complexity among bacteria. Cyanobacteria must be able to reorganize the membranes, synthesize new membrane lipids, and properly target proteins to the correct membrane system. The outer membrane, plasma membrane, and thylakoid membranes each have specialized roles in the cyanobacterial cell. Understanding the organization, functionality, protein composition and dynamics of the membrane systems remains a great challenge in cyanobacterial cell biology.

  8. Photodynamic therapy against cyanobacteria.

    PubMed

    Drábková, M; Marsálek, B; Admiraal, W

    2007-02-01

    This study explores the use of photosensitizers and reactive oxygen species (ROS) to limit growth of cyanobacteria. We chose 12 phthalocyanines, tetraphenol porphyrine, and methylene blue as compounds producing singlet oxygen. Hydrogen peroxide was chosen as another source of ROS. These compounds were tested using algal toxicity tests in microplates on three cultures of green algae (Pseudokirchneriella subcapitata, Scenedesmus quadricauda, and Chlorella kessleri) and on three cultures of cyanobacteria (Synechococcus nidulans, Microcystis incerta, and Anabaena sp.). Results indicate that photosensitizers and singlet oxygen could be highly toxic for some selected phytoplankton species. Green alga Scenedesmus quadricauda was highly sensitive (EC50 = 0.07 mg/L) to compounds producing singlet oxygen, although it was not sensitive to hydrogen peroxide, which was about 10 times more toxic for cyanobacteria. We conclude that the compounds producing hydroxyl radical species seems to be more promising to treat cyanobacterial blooms than the compounds producing the singlet oxygen. PMID:17295267

  9. The toxins of Cyanobacteria.

    PubMed

    Patocka, J

    2001-01-01

    Cyanobacteria, formerly called "blue-green algae", are simple, primitive photosynthetic microorganism wide occurrence in fresh, brackish and salt waters. Forty different genera of Cyanobacteria are known and many of them are producers of potent toxins responsible for a wide array of human illnesses, aquatic mammal and bird morbidity and mortality, and extensive fish kills. These cyanotoxins act as neurotoxins or hepatotoxins and are structurally and functionally diverse, and many are derived from unique biosynthetic pathways. All known cyanotoxins and their chemical and toxicological characteristics are presented in this article.

  10. Differential Responses of Dinitrogen Fixation, Diazotrophic Cyanobacteria and Ammonia Oxidation Reveal a Potential Warming-Induced Imbalance of the N-Cycle in Biological Soil Crusts

    PubMed Central

    Zhou, Xiaobing; Smith, Hilda; Giraldo Silva, Ana; Belnap, Jayne; Garcia-Pichel, Ferran

    2016-01-01

    N2 fixation and ammonia oxidation (AO) are the two most important processes in the nitrogen (N) cycle of biological soil crusts (BSCs). We studied the short-term response of acetylene reduction assay (ARA) rates, an indicator of potential N2 fixation, and AO rates to temperature (T, -5°C to 35°C) in BSC of different successional stages along the BSC ecological succession and geographic origin (hot Chihuahuan and cooler Great Basin deserts). ARA in all BSCs increased with T until saturation occurred between 15 and 20°C, and declined at 30–35°C. Culture studies using cyanobacteria isolated from these crusts indicated that the saturating effect was traceable to their inability to grow well diazotrophically within the high temperature range. Below saturation, temperature response was exponential, with Q10 significantly different in the two areas (~ 5 for Great Basin BSCs; 2–3 for Chihuahuan BSCs), but similar between the two successional stages. However, in contrast to ARA, AO showed a steady increase to 30–35°C in Great Basin, and Chihuhuan BSCs showed no inhibition at any tested temperature. The T response of AO also differed significantly between Great Basin (Q10 of 4.5–4.8) and Chihuahuan (Q10 of 2.4–2.6) BSCs, but not between successional stages. Response of ARA rates to T did not differ from that of AO in either desert. Thus, while both processes scaled to T in unison until 20°C, they separated to an increasing degree at higher temperature. As future warming is likely to occur in the regions where BSCs are often the dominant living cover, this predicted decoupling is expected to result in higher proportion of nitrates in soil relative to ammonium. As nitrate is more easily lost as leachate or to be reduced to gaseous forms, this could mean a depletion of soil N over large landscapes globally. PMID:27776160

  11. Terpenoids and Their Biosynthesis in Cyanobacteria

    PubMed Central

    Pattanaik, Bagmi; Lindberg, Pia

    2015-01-01

    Terpenoids, or isoprenoids, are a family of compounds with great structural diversity which are essential for all living organisms. In cyanobacteria, they are synthesized from the methylerythritol-phosphate (MEP) pathway, using glyceraldehyde 3-phosphate and pyruvate produced by photosynthesis as substrates. The products of the MEP pathway are the isomeric five-carbon compounds isopentenyl diphosphate and dimethylallyl diphosphate, which in turn form the basic building blocks for formation of all terpenoids. Many terpenoid compounds have useful properties and are of interest in the fields of pharmaceuticals and nutrition, and even potentially as future biofuels. The MEP pathway, its function and regulation, and the subsequent formation of terpenoids have not been fully elucidated in cyanobacteria, despite its relevance for biotechnological applications. In this review, we summarize the present knowledge about cyanobacterial terpenoid biosynthesis, both regarding the native metabolism and regarding metabolic engineering of cyanobacteria for heterologous production of non-native terpenoids. PMID:25615610

  12. Identification of toxic Cyanobacteria in Lake Baikal.

    PubMed

    Belykh, O I; Gladkikh, A S; Sorokovikova, E G; Tikhonova, I V; Butina, T V

    2015-01-01

    Cyanobacteria of the genera Anabaena and Microcystis, containing genes for the synthesis of-microcystins (hepatotoxic cyanotoxins) were found for the first time in the coastal zone of Lake Baikal near-the village of Turka, where a tourism and recreational complex were constructed. According to the enzyme-immunoassay, microcystin concentration in water was 0.17 ± 0.01 µg/L. Using 16S rRNA gene pyrosequencing, we found 3936 sequences in the eubacterial community of central basin of Lake Baikal. The summer bacterioplankton in both littoral and pelagic areas of the lake was dominated by the phylum Cyanobacteria, whereas a higher diversity of cyanobacteria was recorded in the plankton of the littoral zone. Moreover, the-potentially toxic Anabaena and Microcystis were detected in this area.

  13. Feeding by coral reef mesograzers: algae or cyanobacteria?

    NASA Astrophysics Data System (ADS)

    Cruz-Rivera, Edwin; Paul, Valerie J.

    2006-11-01

    Marine studies on herbivory have addressed the role of algae as food and shelter for small consumers, but the potential of benthic cyanobacteria to play similar roles is largely unknown. Here, feeding preferences were measured for eight invertebrate consumers from Guam, offered four common macroalgae and two cyanobacteria. The survivorship of another consumer raised on either macroalgae or cyanobacteria was also assessed. From the choices offered, the sacoglossans Elysia rufescens and E. ornata consumed the green macroalga Bryopsis pennata. The crab Menaethius monoceros preferred the red alga Acanthophora spicifera. The amphipods Parhyale hawaiensis and Cymadusa imbroglio consumed macroalgae and cyanobacteria in equivalent amounts, with C. imbroglio showing less selectivity among diets. In contrast to these patterns, in these assays the gastropods Stylocheilus striatus, Haminoea cymbalum, H. ovalis, and Haminoea sp. fed exclusively, or survived only, on cyanobacteria. Preferences for different cyanobacteria varied. Field surveys of cyanobacteria-associated species yielded 34 different invertebrate taxa and suggested different degrees of specificity in these associations. Tropical mesograzers exploit considerably different food resources, with some species adapted to consume cyanobacterial mats. Benthic cyanobacteria may play important roles as food and shelter for marine consumers and may indirectly influence local biodiversity through their associated fauna.

  14. Ultraviolet radiation and cyanobacteria.

    PubMed

    Rastogi, Rajesh Prasad; Sinha, Rajeshwar P; Moh, Sang Hyun; Lee, Taek Kyun; Kottuparambil, Sreejith; Kim, Youn-Jung; Rhee, Jae-Sung; Choi, Eun-Mi; Brown, Murray T; Häder, Donat-Peter; Han, Taejun

    2014-12-01

    Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed.

  15. Ultraviolet radiation and cyanobacteria.

    PubMed

    Rastogi, Rajesh Prasad; Sinha, Rajeshwar P; Moh, Sang Hyun; Lee, Taek Kyun; Kottuparambil, Sreejith; Kim, Youn-Jung; Rhee, Jae-Sung; Choi, Eun-Mi; Brown, Murray T; Häder, Donat-Peter; Han, Taejun

    2014-12-01

    Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed. PMID:25463663

  16. Sensitivity of salad greens (Lactuca sativa L. and Eruca sativa Mill.) exposed to crude extracts of toxic and non-toxic cyanobacteria.

    PubMed

    Bittencourt-Oliveira, M C; Hereman, T C; Macedo-Silva, I; Cordeiro-Araújo, M K; Sasaki, F F C; Dias, C T S

    2015-05-01

    We evaluated the effect of crude extracts of the microcystin-producing (MC+) cyanobacteria Microcystis aeruginosa on seed germination and initial development of lettuce and arugula, at concentrations between 0.5 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent, and compared it to crude extracts of the same species without the toxin (MC-). Crude extracts of the cyanobacteria with MC (+) and without MC (-) caused different effects on seed germination and initial development of the salad green seedlings, lettuce being more sensitive to both extracts when compared to arugula. Crude extracts of M. aeruginosa (MC+) caused more evident effects on seed germination and initial development of both species of salad greens than MC-. Concentrations of 75 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent induced a greater occurrence of abnormal seedlings in lettuce, due to necrosis of the radicle and shortening of this organ in normal seedlings, as well as the reduction in total chlorophyll content and increase in the activity of the antioxidant enzyme peroxidase (POD). The MC- extract caused no harmful effects to seed germination and initial development of seedlings of arugula. However, in lettuce, it caused elevation of POD enzyme activity, decrease in seed germination at concentrations of 75 μg.L(-1) (MC-75) and 100 μg.L(-1) (MC-100), and shortening of the radicle length, suggesting that other compounds present in the cyanobacteria extracts contributed to this result. Crude extracts of M. aeruginosa (MC-) may contain other compounds, besides the cyanotoxins, capable of causing inhibitory or stimulatory effects on seed germination and initial development of salad green seedlings. Arugula was more sensitive to the crude extracts of M. aeruginosa (MC+) and (MC-) and to other possible compounds produced by the cyanobacteria.

  17. Sensitivity of salad greens (Lactuca sativa L. and Eruca sativa Mill.) exposed to crude extracts of toxic and non-toxic cyanobacteria.

    PubMed

    Bittencourt-Oliveira, M C; Hereman, T C; Macedo-Silva, I; Cordeiro-Araújo, M K; Sasaki, F F C; Dias, C T S

    2015-05-01

    We evaluated the effect of crude extracts of the microcystin-producing (MC+) cyanobacteria Microcystis aeruginosa on seed germination and initial development of lettuce and arugula, at concentrations between 0.5 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent, and compared it to crude extracts of the same species without the toxin (MC-). Crude extracts of the cyanobacteria with MC (+) and without MC (-) caused different effects on seed germination and initial development of the salad green seedlings, lettuce being more sensitive to both extracts when compared to arugula. Crude extracts of M. aeruginosa (MC+) caused more evident effects on seed germination and initial development of both species of salad greens than MC-. Concentrations of 75 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent induced a greater occurrence of abnormal seedlings in lettuce, due to necrosis of the radicle and shortening of this organ in normal seedlings, as well as the reduction in total chlorophyll content and increase in the activity of the antioxidant enzyme peroxidase (POD). The MC- extract caused no harmful effects to seed germination and initial development of seedlings of arugula. However, in lettuce, it caused elevation of POD enzyme activity, decrease in seed germination at concentrations of 75 μg.L(-1) (MC-75) and 100 μg.L(-1) (MC-100), and shortening of the radicle length, suggesting that other compounds present in the cyanobacteria extracts contributed to this result. Crude extracts of M. aeruginosa (MC-) may contain other compounds, besides the cyanotoxins, capable of causing inhibitory or stimulatory effects on seed germination and initial development of salad green seedlings. Arugula was more sensitive to the crude extracts of M. aeruginosa (MC+) and (MC-) and to other possible compounds produced by the cyanobacteria. PMID:26132007

  18. An Acute Case of Intoxication with Cyanobacteria and Cyanotoxins in Recreational Water in Salto Grande Dam, Argentina

    PubMed Central

    Giannuzzi, Leda; Sedan, Daniela; Echenique, Ricardo; Andrinolo, Dario

    2011-01-01

    Cyanobacterial blooms and hepatotoxic microcystins (MCs) usually occur in summer, constituting a sanitary and environmental problem in Salto Grande Dam, Argentina. Water sports and recreational activities take place in summer in this lake. We reported an acute case of cyanobacterial poisoning in Salto Grande dam, Argentina, which occurred in January 2007. Accidentally, a young man was immersed in an intense bloom of Microcystis spp. A level of 48.6 μg·L−1 of microcystin-LR was detected in water samples. Four hours after exposure, the patient showed nausea, abdominal pain and fever. Three days later, dyspnea and respiratory distress were reported. The patient was hospitalized in intensive care and diagnosed with an atypical pneumonia. Finally, a week after the exposure, the patient developed a hepatotoxicosis with a significant increase of hepatic damage biomarkers (ALT, AST and γGT). Complete recovery took place within 20 days. This is the first study to show an acute intoxication with microcystin-producing cyanobacteria blooms in recreational water. PMID:22163179

  19. Cyanobacteria as photosynthetic biocatalysts: a systems biology perspective.

    PubMed

    Gudmundsson, Steinn; Nogales, Juan

    2015-01-01

    The increasing need to replace oil-based products and to address global climate change concerns has triggered considerable interest in photosynthetic microorganisms. Cyanobacteria, in particular, have great potential as biocatalysts for fuels and fine-chemicals. During the last few years the biotechnological applications of cyanobacteria have experienced an unprecedented increase and the use of these photosynthetic organisms for chemical production is becoming a tangible reality. However, the field is still immature and many concerns about the economic feasibility of the biotechnological potential of cyanobacteria remain. In this review we describe recent successes in biofuel and fine-chemical production using cyanobacteria. We discuss the role of the photosynthetic metabolism and highlight the need for systems-level metabolic optimization in order to achieve the true potential of cyanobacterial biocatalysts.

  20. Antifungal compounds from cyanobacteria.

    PubMed

    Shishido, Tânia K; Humisto, Anu; Jokela, Jouni; Liu, Liwei; Wahlsten, Matti; Tamrakar, Anisha; Fewer, David P; Permi, Perttu; Andreote, Ana P D; Fiore, Marli F; Sivonen, Kaarina

    2015-04-13

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.

  1. Antifungal Compounds from Cyanobacteria

    PubMed Central

    Shishido, Tânia K.; Humisto, Anu; Jokela, Jouni; Liu, Liwei; Wahlsten, Matti; Tamrakar, Anisha; Fewer, David P.; Permi, Perttu; Andreote, Ana P. D.; Fiore, Marli F.; Sivonen, Kaarina

    2015-01-01

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders. PMID:25871291

  2. Nitrogen Fixation and Hydrogen Metabolism in Cyanobacteria

    PubMed Central

    Bothe, Hermann; Schmitz, Oliver; Yates, M. Geoffrey; Newton, William E.

    2010-01-01

    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. PMID:21119016

  3. Cyanobacteria blooms: effects on aquatic ecosystems.

    PubMed

    Havens, Karl E

    2008-01-01

    Cyanobacteria become increasingly dominant as concentrations of TP and TN increase during eutrophication of lakes, rivers and estuaries. Temporal dynamics of cyanobacteria blooms are variable--in some systems persistent blooms occur in summer to fall, whereas in other systems blooms are more sporadic. Cyanobacteria blooms have a wide range of possible biological impacts including potential toxic effects on other algae, invertebrates and fish, impacts to plants and benthic algae due to shading, and impacts to food web function as large inedible algae produce a bottleneck to C and energy flow in the plankton food web. In lakes with dense blooms of cyanobacteria, accumulation of organic material in lake sediments and increased bacterial activity also may lead to anoxic conditions that alter the structure of benthic macro-invertebrates. Diffusive internal P loading may increase, and hypolimnetic anoxia may lead to a loss of piscivorous fish that require a summer cold water refuge in temperate lakes. Ecosystem changes associated with frequent blooms may result in delayed response of lakes, rivers and estuaries to external nutrient load reduction. Despite numerous case studies and a vast literature on species-specific responses, community level effects of cyanobacterial blooms are not well understood--in particular the realized impacts of toxins and changes in food web structure/function. These areas require additional research given the prevalence of toxic blooms in the nation's lakes, rivers and coastal waters--systems that provide a wide range of valued ecosystem services. PMID:18461790

  4. Cyanobacteria as a Source for Novel Anti-Leukemic Compounds.

    PubMed

    Humisto, Anu; Herfindal, Lars; Jokela, Jouni; Karkman, Antti; Bjørnstad, Ronja; Choudhury, Romi R; Sivonen, Kaarina

    2016-01-01

    Cyanobacteria are an inspiring source of bioactive secondary metabolites. These bioactive agents are a diverse group of compounds which are varying in their bioactive targets, the mechanisms of action, and chemical structures. Cyanobacteria from various environments, especially marine benthic cyanobacteria, are found to be rich sources for the search for novel bioactive compounds. Several compounds with anticancer activities have been discovered from cyanobacteria and some of these have succeeded to enter the clinical trials. Varying anticancer agents are needed to overcome increasing challenges in cancer treatments. Different search methods are used to reveal anticancer compounds from natural products, but cell based methods are the most common. Cyanobacterial bioactive compounds as agents against acute myeloid leukemia are not well studied. Here we examined our new results combined with previous studies of anti-leukemic compounds from cyanobacteria with emphasis to reveal common features in strains producing such activity. We report that cyanobacteria harbor specific anti-leukemic compounds since several studied strains induced apoptosis against AML cells but were inactive against non-malignant cells like hepatocytes. We noted that particularly benthic strains from the Baltic Sea, such as Anabaena sp., were especially potential AML apoptosis inducers. Taken together, this review and re-analysis of data demonstrates the power of maintaining large culture collections for the search for novel bioactivities, and also how anti-AML activity in cyanobacteria can be revealed by relatively simple and low-cost assays.

  5. Geographical patterns in cyanobacteria distribution: climate influence at regional scale.

    PubMed

    Pitois, Frédéric; Thoraval, Isabelle; Baurès, Estelle; Thomas, Olivier

    2014-01-28

    Cyanobacteria are a component of public health hazards in freshwater environments because of their potential as toxin producers. Eutrophication has long been considered the main cause of cyanobacteria outbreak and proliferation, whereas many studies emphasized the effect of abiotic parameters (mainly temperature and light) on cell growth rate or toxin production. In view of the growing concerns of global change consequences on public health parameters, this study attempts to enlighten climate influence on cyanobacteria at regional scale in Brittany (NW France). The results show that homogeneous cyanobacteria groups are associated with climatic domains related to temperature, global radiation and pluviometry, whereas microcystins (MCs) occurrences are only correlated to local cyanobacteria species composition. As the regional climatic gradient amplitude is similar to the projected climate evolution on a 30-year timespan, a comparison between the present NW and SE situations was used to extrapolate the evolution of geographical cyanobacteria distribution in Brittany. Cyanobacteria composition should shift toward species associated with more frequent Microcystins occurrences along a NW/SE axis whereas lakes situated along a SW/NE axis should transition to species (mainly Nostocales) associated with lower MCs detection frequencies.

  6. Upwelling events may cause cyanobacteria blooms in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Wasmund, Norbert; Nausch, Günther; Voss, Maren

    2012-02-01

    Cyanobacteria blooms in the Baltic Sea appear after upwelling events, which transport phosphate-rich intermediate water to the surface. The growth potential of diazotrophic cyanobacteria in upwelled water was studied in a mesocosm (tank) experiment in summer 2007. An Anabaena bloom was only induced in the tanks filled with upwelled surface water but not in those filled with surface water from outside the upwelling cell and with intermediate water. The low initial cyanobacteria biomass in the intermediate water could not grow to bloom concentrations within three weeks. It is concluded that mixing of upwelled water with surrounding surface water forms a precondition for a cyanobacteria bloom. An additional mesocosm experiment conducted in 2009 revealed that mixing of intermediate water with surface water had the same stimulating effect on nitrogen fixation and cyanobacteria growth as artificial phosphate input. Phosphate input stimulates the growth of Nodularia and Anabaena more than that of Aphanizomenon. We suggest that the upwelled phosphate-rich intermediate water has to be mixed with the surface water containing physiologically “young” cyanobacteria biomass of at least 20 mg/m3 as an inoculum in order to initiate a cyanobacteria bloom.

  7. Geographical Patterns in Cyanobacteria Distribution: Climate Influence at Regional Scale

    PubMed Central

    Pitois, Frédéric; Thoraval, Isabelle; Baurès, Estelle; Thomas, Olivier

    2014-01-01

    Cyanobacteria are a component of public health hazards in freshwater environments because of their potential as toxin producers. Eutrophication has long been considered the main cause of cyanobacteria outbreak and proliferation, whereas many studies emphasized the effect of abiotic parameters (mainly temperature and light) on cell growth rate or toxin production. In view of the growing concerns of global change consequences on public health parameters, this study attempts to enlighten climate influence on cyanobacteria at regional scale in Brittany (NW France). The results show that homogeneous cyanobacteria groups are associated with climatic domains related to temperature, global radiation and pluviometry, whereas microcystins (MCs) occurrences are only correlated to local cyanobacteria species composition. As the regional climatic gradient amplitude is similar to the projected climate evolution on a 30-year timespan, a comparison between the present NW and SE situations was used to extrapolate the evolution of geographical cyanobacteria distribution in Brittany. Cyanobacteria composition should shift toward species associated with more frequent Microcystins occurrences along a NW/SE axis whereas lakes situated along a SW/NE axis should transition to species (mainly Nostocales) associated with lower MCs detection frequencies. PMID:24476711

  8. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge

    PubMed Central

    Martins, Joana; Vasconcelos, Vitor

    2015-01-01

    Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential. PMID:26580631

  9. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge.

    PubMed

    Martins, Joana; Vasconcelos, Vitor

    2015-11-13

    Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential.

  10. Fluorescent minerals - A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments

    NASA Astrophysics Data System (ADS)

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark.

  11. Fluorescent minerals--A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments.

    PubMed

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark.

  12. Fluorescent minerals--A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments.

    PubMed

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark. PMID:26256632

  13. MCEARD - CYANOBACTERIA AND THEIR TOXINS

    EPA Science Inventory

    Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Waterborne cyanobacteria and their highly potent toxins are a significant hazard for human health and the ecosystem....

  14. Cyanobacteria-bryophyte symbioses.

    PubMed

    Adams, David G; Duggan, Paula S

    2008-01-01

    Cyanobacteria are a large group of photosynthetic prokaryotes of enormous environmental importance, being responsible for a large proportion of global CO(2) and N(2) fixation. They form symbiotic associations with a wide range of eukaryotic hosts including plants, fungi, sponges, and protists. The cyanobacterial symbionts are often filamentous and fix N(2) in specialized cells known as heterocysts, enabling them to provide the host with fixed nitrogen and, in the case of non-photosynthetic hosts, with fixed carbon. The best studied cyanobacterial symbioses are those with plants, in which the cyanobacteria can infect the roots, stems, leaves, and, in the case of the liverworts and hornworts, the subject of this review, the thallus. The symbionts are usually Nostoc spp. that gain entry to the host by means of specialized motile filaments known as hormogonia. The host plant releases chemical signals that stimulate hormogonia formation and, by chemoattraction, guide the hormogonia to the point of entry into the plant tissue. Inside the symbiotic cavity, host signals inhibit further hormogonia formation and stimulate heterocyst development and dinitrogen fixation. The cyanobionts undergo morphological and physiological changes, including reduced growth rate and CO(2) fixation, and enhanced N(2) fixation, and release to the plant much of the dinitrogen fixed. This short review summarizes knowledge of the cyanobacterial symbioses with liverworts and hornworts, with particular emphasis on the importance of pili and gliding motility for the symbiotic competence of hormogonia.

  15. Origin of marine planktonic cyanobacteria.

    PubMed

    Sánchez-Baracaldo, Patricia

    2015-12-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya).

  16. Origin of marine planktonic cyanobacteria

    PubMed Central

    Sánchez-Baracaldo, Patricia

    2015-01-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600–2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500–542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600–1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000–542 Mya). PMID:26621203

  17. Oleic acid biosynthesis in cyanobacteria

    SciTech Connect

    VanDusen, W.J.; Jaworski, J.G.

    1986-05-01

    The biosynthesis of fatty acids in cyanobacteria is very similar to the well characterized system found in green plants. However, the initial desaturation of stearic acid in cyanobacteria appears to represent a significant departure from plant systems in which stearoyl-ACP is the exclusive substrate for desaturation. In Anabaena variabilis, the substrate appears to be monoglucosyldiacylglycerol, a lipid not found in plants. The authors examined five different cyanobacteria to determine if the pathway in A. variabilis was generally present in other cyanobacteria. The cyanobacteria studied were A. variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis marina, and Anacystis nidulans. Each were grown in liquid culture, harvested, and examined for stearoyl-ACP desaturase activity or incubated with /sup 14/CO/sub 2/. None of the cyanobacteria contained any stearoyl-ACP desaturase activity in whole homogenates or 105,000g supernatants. All were capable of incorporating /sup 14/CO/sub 2/ into monoglucosyldiacylglycerol and results from incubations of 20 min, 1 hr, 1 hr + 10 hr chase were consistent with monoglucosyldiacylglycerol serving as precursor for monogalctosyldiacylglycerol. Thus, initial evidence is consistent with oleic acid biosynthesis occurring by desaturation of stearoyl-monoglucosyldiacylglycerol in all cyanobacteria.

  18. Origin of marine planktonic cyanobacteria.

    PubMed

    Sánchez-Baracaldo, Patricia

    2015-01-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya). PMID:26621203

  19. Genetic engineering of cyanobacteria as biodiesel feedstock.

    SciTech Connect

    Ruffing, Anne.; Trahan, Christine Alexandra; Jones, Howland D. T.

    2013-01-01

    Algal biofuels are a renewable energy source with the potential to replace conventional petroleum-based fuels, while simultaneously reducing greenhouse gas emissions. The economic feasibility of commercial algal fuel production, however, is limited by low productivity of the natural algal strains. The project described in this SAND report addresses this low algal productivity by genetically engineering cyanobacteria (i.e. blue-green algae) to produce free fatty acids as fuel precursors. The engineered strains were characterized using Sandias unique imaging capabilities along with cutting-edge RNA-seq technology. These tools are applied to identify additional genetic targets for improving fuel production in cyanobacteria. This proof-of-concept study demonstrates successful fuel production from engineered cyanobacteria, identifies potential limitations, and investigates several strategies to overcome these limitations. This project was funded from FY10-FY13 through the President Harry S. Truman Fellowship in National Security Science and Engineering, a program sponsored by the LDRD office at Sandia National Laboratories.

  20. Chemodiversity in Freshwater and Terrestrial Cyanobacteria – a Source for Drug Discovery

    PubMed Central

    Chlipala, George E.; Mo, Shunyan; Orjala, Jimmy

    2011-01-01

    Cyanobacteria are considered a promising source for new pharmaceutical lead compounds and a large number of chemically diverse and bioactive metabolites have been obtained from cyanobacteria over the last few decades. This review highlights the structural diversity of natural products from freshwater and terrestrial cyanobacteria. The review is divided into three areas: cytotoxic metabolites, protease inhibitors, and antimicrobial metabolites. The first section discusses the potent cytotoxins cryptophycin and tolytoxin. The second section covers protease inhibitors from freshwater and terrestrial cyanobacteria and is divided in five subsections according to structural class: aeruginosins, cyanopeptolins, microviridins, anabaenopeptins, and microginins. Structure activity relationships are discussed within each protease inhibitor class. The third section, antimicrobial metabolites from freshwater and terrestrial cyanobacteria, is divided by chemical class in three subsections: alkaloids, peptides and terpenoids. These examples emphasize the structural diversity and drug development potential of natural products from freshwater and terrestrial cyanobacteria. PMID:21561419

  1. Hydrogen production by Cyanobacteria

    PubMed Central

    Dutta, Debajyoti; De, Debojyoti; Chaudhuri, Surabhi; Bhattacharya, Sanjoy K

    2005-01-01

    The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical), Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source. PMID:16371161

  2. Cyanobacteria: Photoautotrophic Microbial Factories for the Sustainable Synthesis of Industrial Products.

    PubMed

    Lau, Nyok-Sean; Matsui, Minami; Abdullah, Amirul Al-Ashraf

    2015-01-01

    Cyanobacteria are widely distributed Gram-negative bacteria with a long evolutionary history and the only prokaryotes that perform plant-like oxygenic photosynthesis. Cyanobacteria possess several advantages as hosts for biotechnological applications, including simple growth requirements, ease of genetic manipulation, and attractive platforms for carbon neutral production process. The use of photosynthetic cyanobacteria to directly convert carbon dioxide to biofuels is an emerging area of interest. Equipped with the ability to degrade environmental pollutants and remove heavy metals, cyanobacteria are promising tools for bioremediation and wastewater treatment. Cyanobacteria are characterized by the ability to produce a spectrum of bioactive compounds with antibacterial, antifungal, antiviral, and antialgal properties that are of pharmaceutical and agricultural significance. Several strains of cyanobacteria are also sources of high-value chemicals, for example, pigments, vitamins, and enzymes. Recent advances in biotechnological approaches have facilitated researches directed towards maximizing the production of desired products in cyanobacteria and realizing the potential of these bacteria for various industrial applications. In this review, the potential of cyanobacteria as sources of energy, bioactive compounds, high-value chemicals, and tools for aquatic bioremediation and recent progress in engineering cyanobacteria for these bioindustrial applications are discussed.

  3. Cyanobacteria: Photoautotrophic Microbial Factories for the Sustainable Synthesis of Industrial Products.

    PubMed

    Lau, Nyok-Sean; Matsui, Minami; Abdullah, Amirul Al-Ashraf

    2015-01-01

    Cyanobacteria are widely distributed Gram-negative bacteria with a long evolutionary history and the only prokaryotes that perform plant-like oxygenic photosynthesis. Cyanobacteria possess several advantages as hosts for biotechnological applications, including simple growth requirements, ease of genetic manipulation, and attractive platforms for carbon neutral production process. The use of photosynthetic cyanobacteria to directly convert carbon dioxide to biofuels is an emerging area of interest. Equipped with the ability to degrade environmental pollutants and remove heavy metals, cyanobacteria are promising tools for bioremediation and wastewater treatment. Cyanobacteria are characterized by the ability to produce a spectrum of bioactive compounds with antibacterial, antifungal, antiviral, and antialgal properties that are of pharmaceutical and agricultural significance. Several strains of cyanobacteria are also sources of high-value chemicals, for example, pigments, vitamins, and enzymes. Recent advances in biotechnological approaches have facilitated researches directed towards maximizing the production of desired products in cyanobacteria and realizing the potential of these bacteria for various industrial applications. In this review, the potential of cyanobacteria as sources of energy, bioactive compounds, high-value chemicals, and tools for aquatic bioremediation and recent progress in engineering cyanobacteria for these bioindustrial applications are discussed. PMID:26199945

  4. Cyanobacteria: Photoautotrophic Microbial Factories for the Sustainable Synthesis of Industrial Products

    PubMed Central

    Lau, Nyok-Sean; Matsui, Minami; Abdullah, Amirul Al-Ashraf

    2015-01-01

    Cyanobacteria are widely distributed Gram-negative bacteria with a long evolutionary history and the only prokaryotes that perform plant-like oxygenic photosynthesis. Cyanobacteria possess several advantages as hosts for biotechnological applications, including simple growth requirements, ease of genetic manipulation, and attractive platforms for carbon neutral production process. The use of photosynthetic cyanobacteria to directly convert carbon dioxide to biofuels is an emerging area of interest. Equipped with the ability to degrade environmental pollutants and remove heavy metals, cyanobacteria are promising tools for bioremediation and wastewater treatment. Cyanobacteria are characterized by the ability to produce a spectrum of bioactive compounds with antibacterial, antifungal, antiviral, and antialgal properties that are of pharmaceutical and agricultural significance. Several strains of cyanobacteria are also sources of high-value chemicals, for example, pigments, vitamins, and enzymes. Recent advances in biotechnological approaches have facilitated researches directed towards maximizing the production of desired products in cyanobacteria and realizing the potential of these bacteria for various industrial applications. In this review, the potential of cyanobacteria as sources of energy, bioactive compounds, high-value chemicals, and tools for aquatic bioremediation and recent progress in engineering cyanobacteria for these bioindustrial applications are discussed. PMID:26199945

  5. Ethanol synthesis by genetic engineering in cyanobacteria

    SciTech Connect

    Deng, M.D.; Coleman, J.R.

    1999-02-01

    Cyanobacteria are autotrophic prokaryotes which carry out oxygenic photosynthesis and accumulate glycogen as the major form of stored carbon. In this research, the authors 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, the pdc 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, CO{sub 2}, and inorganic elements efficiently, production of ethanol by cyanobacteria is a potential system for bioconversion of solar energy and CO{sub 2} into a valuable resource.

  6. Regulatory RNAs in photosynthetic cyanobacteria.

    PubMed

    Kopf, Matthias; Hess, Wolfgang R

    2015-05-01

    Regulatory RNAs play versatile roles in bacteria in the coordination of gene expression during various physiological processes, especially during stress adaptation. Photosynthetic bacteria use sunlight as their major energy source. Therefore, they are particularly vulnerable to the damaging effects of excess light or UV irradiation. In addition, like all bacteria, photosynthetic bacteria must adapt to limiting nutrient concentrations and abiotic and biotic stress factors. Transcriptome analyses have identified hundreds of potential regulatory small RNAs (sRNAs) in model cyanobacteria such as Synechocystis sp. PCC 6803 or Anabaena sp. PCC 7120, and in environmentally relevant genera such as Trichodesmium, Synechococcus and Prochlorococcus. Some sRNAs have been shown to actually contain μORFs and encode short proteins. Examples include the 40-amino-acid product of the sml0013 gene, which encodes the NdhP subunit of the NDH1 complex. In contrast, the functional characterization of the non-coding sRNA PsrR1 revealed that the 131 nt long sRNA controls photosynthetic functions by targeting multiple mRNAs, providing a paradigm for sRNA functions in photosynthetic bacteria. We suggest that actuatons comprise a new class of genetic elements in which an sRNA gene is inserted upstream of a coding region to modify or enable transcription of that region.

  7. Circadian Rhythms in Cyanobacteria.

    PubMed

    Cohen, Susan E; Golden, Susan S

    2015-12-01

    Life on earth is subject to daily and predictable fluctuations in light intensity, temperature, and humidity created by rotation of the earth. Circadian rhythms, generated by a circadian clock, control temporal programs of cellular physiology to facilitate adaptation to daily environmental changes. Circadian rhythms are nearly ubiquitous and are found in both prokaryotic and eukaryotic organisms. Here we introduce the molecular mechanism of the circadian clock in the model cyanobacterium Synechococcus elongatus PCC 7942. We review the current understanding of the cyanobacterial clock, emphasizing recent work that has generated a more comprehensive understanding of how the circadian oscillator becomes synchronized with the external environment and how information from the oscillator is transmitted to generate rhythms of biological activity. These results have changed how we think about the clock, shifting away from a linear model to one in which the clock is viewed as an interactive network of multifunctional components that are integrated into the context of the cell in order to pace and reset the oscillator. We conclude with a discussion of how this basic timekeeping mechanism differs in other cyanobacterial species and how information gleaned from work in cyanobacteria can be translated to understanding rhythmic phenomena in other prokaryotic systems. PMID:26335718

  8. Learning from 8 years of regional cyanobacteria observation in Brittany in view of sanitary survey improvement.

    PubMed

    Pitois, Frédéric; Thomas, Olivier; Thoraval, Isabelle; Baurès, Estelle

    2014-01-01

    Cyanobacteria and cyanotoxins have been more and more studied during the last decades with regard to environment and health issues. More recently the consequences of climate change reinforced the need for research in view of a better management of cyanobacteria blooms. In this context the exploitation of the water quality survey of 26 recreational lakes in Brittany (north western France) between 2004 and 2011 is reported in this paper in order to encompass spatial and interannual patterns of cyanobacteria development at a regional scale. Starting from weekly data principally acquired during summertime, the links between cyanobacteria cell densities, toxin occurrences and interannual meteorological factors can give insights on the potential evolution of cyanobacterial crisis in the future. This study is part of a project aiming at a better understanding of potentially toxic cyanobacteria crisis occurrences in recreational waters, in order to improve predictive monitoring routines.

  9. Genome fluctuations in cyanobacteria reflect evolutionary, developmental and adaptive traits

    PubMed Central

    2011-01-01

    Background Cyanobacteria belong to an ancient group of photosynthetic prokaryotes with pronounced variations in their cellular differentiation strategies, physiological capacities and choice of habitat. Sequencing efforts have shown that genomes within this phylum are equally diverse in terms of size and protein-coding capacity. To increase our understanding of genomic changes in the lineage, the genomes of 58 contemporary cyanobacteria were analysed for shared and unique orthologs. Results A total of 404 protein families, present in all cyanobacterial genomes, were identified. Two of these are unique to the phylum, corresponding to an AbrB family transcriptional regulator and a gene that escapes functional annotation although its genomic neighbourhood is conserved among the organisms examined. The evolution of cyanobacterial genome sizes involves a mix of gains and losses in the clade encompassing complex cyanobacteria, while a single event of reduction is evident in a clade dominated by unicellular cyanobacteria. Genome sizes and gene family copy numbers evolve at a higher rate in the former clade, and multi-copy genes were predominant in large genomes. Orthologs unique to cyanobacteria exhibiting specific characteristics, such as filament formation, heterocyst differentiation, diazotrophy and symbiotic competence, were also identified. An ancestral character reconstruction suggests that the most recent common ancestor of cyanobacteria had a genome size of approx. 4.5 Mbp and 1678 to 3291 protein-coding genes, 4%-6% of which are unique to cyanobacteria today. Conclusions The different rates of genome-size evolution and multi-copy gene abundance suggest two routes of genome development in the history of cyanobacteria. The expansion strategy is driven by gene-family enlargment and generates a broad adaptive potential; while the genome streamlining strategy imposes adaptations to highly specific niches, also reflected in their different functional capacities. A few

  10. cyanoScope: Mapping cyanobacteria one slide at a time

    EPA Science Inventory

    cyanoScope is a new initiative for engaging the public, and particularly citizen scientists, to assist with mapping potentially harmful algal blooms throughout New England. Cyanobacteria are important members of the phytoplankton assemblages in lakes. In most situations these p...

  11. Early Earth: Cyanobacteria at work

    NASA Astrophysics Data System (ADS)

    Kaufman, Alan J.

    2014-04-01

    Oxygen-producing photosynthesis must have evolved before the pervasive oxidation of the atmosphere around 2.4 billion years ago, but how long before is unclear. Geochemical analyses of ancient sedimentary rocks now suggest that cyanobacteria generated oxygen at least 3 billion years ago.

  12. The chemical ecology of cyanobacteria

    PubMed Central

    Leão, Pedro N.; Engene, Niclas; Antunes, Agostinho; Gerwick, William H.; Vasconcelos, Vitor

    2014-01-01

    This review covers the literature on the chemically mediated ecology of cyanobacteria, including ultraviolet radiation protection, feeding-deterrence, allelopathy, resource competition, and signalling. To highlight the chemical and biological diversity of this group of organisms, evolutionary and chemotaxonomical studies are presented. Several technologically relevant aspects of cyanobacterial chemical ecology are also discussed. PMID:22237837

  13. IRON-TOLERANT CYANOBACTERIA: IMPLICATIONS FOR ASTROBIOLOGY

    NASA Technical Reports Server (NTRS)

    Brown, Igor I.; Allen, Carlton C.; Mummey, Daniel L.; Sarkisova, Svetlana A.; McKay, David S.

    2006-01-01

    The review is dedicated to the new group of extremophiles - iron tolerant cyanobacteria. The authors have analyzed earlier published articles about the ecology of iron tolerant cyanobacteria and their diversity. It was concluded that contemporary iron depositing hot springs might be considered as relative analogs of Precambrian environment. The authors have concluded that the diversity of iron-tolerant cyanobacteria is understudied. The authors also analyzed published data about the physiological peculiarities of iron tolerant cyanobacteria. They made the conclusion that iron tolerant cyanobacteria may oxidize reduced iron through the photosystem of cyanobacteria. The involvement of both Reaction Centers 1 and 2 is also discussed. The conclusion that iron tolerant protocyanobacteria could be involved in banded iron formations generation is also proposed. The possible mechanism of the transition from an oxygenic photosynthesis to an oxygenic one is also discussed. In the final part of the review the authors consider the possible implications of iron tolerant cyanobacteria for astrobiology.

  14. Evaluation of cyanobacteria cell count detection derived from MERIS imagery across the eastern USA

    EPA Science Inventory

    Inland waters across the United States (US) are at potential risk for increased outbreaks of toxic cyanobacteria (Cyano) harmful algal bloom (HAB) events resulting from elevated water temperatures and extreme hydrologic events attributable to climate change and increased nutrient...

  15. In the Limelight: Photoreceptors in Cyanobacteria

    PubMed Central

    2016-01-01

    ABSTRACT Certain cyanobacteria look green if grown in red light and vice versa. This dramatic color change, called complementary chromatic adaptation (CCA), is caused by alterations of the major colored light-harvesting proteins. A major controller of CCA is the cyanobacteriochrome (CBCR) RcaE, a red-green reversible photoreceptor that triggers a complex signal transduction pathway. Now, a new study demonstrates that CCA is also modulated by DpxA, a CBCR that senses yellow and teal (greenish blue) light. DpxA acts to expand the range of wavelengths that can impact CCA, by fine-tuning the process. This dual control of CCA might positively impact the fitness of cells growing in the shade of competing algae or in a water column where light levels and spectral quality change gradually with depth. This discovery adds to the growing number of light-responsive phenomena controlled by multiple CBCRs. Furthermore, the diverse CBCRs which are exclusively found in cyanobacteria have significant biotechnological potential. PMID:27353763

  16. In the Limelight: Photoreceptors in Cyanobacteria.

    PubMed

    Bhaya, Devaki

    2016-01-01

    Certain cyanobacteria look green if grown in red light and vice versa. This dramatic color change, called complementary chromatic adaptation (CCA), is caused by alterations of the major colored light-harvesting proteins. A major controller of CCA is the cyanobacteriochrome (CBCR) RcaE, a red-green reversible photoreceptor that triggers a complex signal transduction pathway. Now, a new study demonstrates that CCA is also modulated by DpxA, a CBCR that senses yellow and teal (greenish blue) light. DpxA acts to expand the range of wavelengths that can impact CCA, by fine-tuning the process. This dual control of CCA might positively impact the fitness of cells growing in the shade of competing algae or in a water column where light levels and spectral quality change gradually with depth. This discovery adds to the growing number of light-responsive phenomena controlled by multiple CBCRs. Furthermore, the diverse CBCRs which are exclusively found in cyanobacteria have significant biotechnological potential. PMID:27353763

  17. Bioactivity of Benthic and Picoplanktonic Estuarine Cyanobacteria on Growth of Photoautotrophs: Inhibition versus Stimulation

    PubMed Central

    Lopes, Viviana R.; Vasconcelos, Vitor M.

    2011-01-01

    Understanding potential biochemical interactions and effects among cyanobacteria and other organisms is one of the main keys to a better knowledge of microbial population structuring and dynamics. In this study, the effects of cyanobacteria from benthos and plankton of estuaries on other cyanobacteria and green algae growth were evaluated. To understand how the estuarine cyanobacteria might influence the dynamics of phytoplankton, experiments were carried out with the freshwater species Microcystis aeruginosa and Chlorella sp., and the marine Synechocystis salina and Nannochloropsis sp. exposed to aqueous and organic (70% methanol) crude extracts of cyanobacteria for 96 h. The most pronounced effect observed was the growth stimulation. Growth inhibition was also observed for S. salina and M. aeruginosa target-species at the highest and lowest concentrations of cyanobacterial extracts. The methanolic crude extract of Phormidium cf. chalybeum LEGE06078 was effective against S. salina growth in a concentration-dependent manner after 96 h-exposure. All of the cyanobacterial isolates showed some bioactivity on the target-species growth, i.e., inhibitory or stimulating effects. These results indicate that the analyzed cyanobacterial isolates can potentially contribute to blooms’ proliferation of other cyanobacteria and to the abnormal growth of green algae disturbing the dynamic of estuarine phytoplankton communities. Since estuaries are transitional ecosystems, the benthic and picoplanktonic estuarine cyanobacteria can change both freshwater and marine phytoplankton succession, competition and bloom formation. Furthermore, a potential biotechnological application of these isolates as a tool to control cyanobacteria and microalgae proliferation can be feasible. This work is the first on the subject of growth responses of photoautotrophs to cyanobacteria from Atlantic estuarine environments. PMID:21673889

  18. Utilization of the terrestrial cyanobacteria

    NASA Astrophysics Data System (ADS)

    Katoh, Hiroshi; Tomita-Yokotani, Kaori; Furukawa, Jun; Kimura, Shunta; Yokoshima, Mika; Yamaguchi, Yuji; Takenaka, Hiroyuki

    The terrestrial, N _{2}-fixing cyanobacterium, Nostoc commune has expected to utilize for agriculture, food and terraforming cause of its extracellular polysaccharide, desiccation tolerance and nitrogen fixation. Previously, the first author indicated that desiccation related genes were analyzed and the suggested that the genes were related to nitrogen fixation and metabolisms. In this report, we suggest possibility of agriculture, using the cyanobacterium. Further, we also found radioactive compounds accumulated N. commune (cyanobacterium) in Fukushima, Japan after nuclear accident. Thus, it is investigated to decontaminate radioactive compounds from the surface soil by the cyanobacterium and showed to accumulate radioactive compounds using the cyanobacterium. We will discuss utilization of terrestrial cyanobacteria under closed environment. Keyword: Desiccation, terrestrial cyanobacteria, bioremediation, agriculture

  19. Collection, purification, and culture of cyanobacteria

    SciTech Connect

    Court, G J; Kycia, J H; Siegelman, H W

    1980-01-01

    Detailed studies of the structure, physiology, biochemistry, and toxin production of cyanobacteria require a dependable and reproducible supply of selected organisms. Axenic cloned strains of cyanobacteria should be used whenever possible. Several physical and chemical techniques are available to purify cultures to the axenic condition. Cultural techniques are described here which can be used to grow adequate amounts, greater than 100 g fresh weight, of cyanobacteria in about four weeks.

  20. Synthetic biology of cyanobacteria: unique challenges and opportunities.

    PubMed

    Berla, Bertram M; Saha, Rajib; Immethun, Cheryl M; Maranas, Costas D; Moon, Tae Seok; Pakrasi, Himadri B

    2013-01-01

    Photosynthetic organisms, and especially cyanobacteria, hold great promise as sources of renewably-produced fuels, bulk and specialty chemicals, and nutritional products. Synthetic biology tools can help unlock cyanobacteria's potential for these functions, but unfortunately tool development for these organisms has lagged behind that for S. cerevisiae and E. coli. While these organisms may in many cases be more difficult to work with as "chassis" strains for synthetic biology than certain heterotrophs, the unique advantages of autotrophs in biotechnology applications as well as the scientific importance of improved understanding of photosynthesis warrant the development of these systems into something akin to a "green E. coli." In this review, we highlight unique challenges and opportunities for development of synthetic biology approaches in cyanobacteria. We review classical and recently developed methods for constructing targeted mutants in various cyanobacterial strains, and offer perspective on what genetic tools might most greatly expand the ability to engineer new functions in such strains. Similarly, we review what genetic parts are most needed for the development of cyanobacterial synthetic biology. Finally, we highlight recent methods to construct genome-scale models of cyanobacterial metabolism and to use those models to measure properties of autotrophic metabolism. Throughout this paper, we discuss some of the unique challenges of a diurnal, autotrophic lifestyle along with how the development of synthetic biology and biotechnology in cyanobacteria must fit within those constraints.

  1. Formation and diagenesis of modern marine calcified cyanobacteria.

    PubMed

    Planavsky, N; Reid, R P; Lyons, T W; Myshrall, K L; Visscher, P T

    2009-12-01

    Calcified cyanobacterial microfossils are common in carbonate environments through most of the Phanerozoic, but are absent from the marine rock record over the past 65 Myr. There has been long-standing debate on the factors controlling the formation and temporal distribution of these fossils, fostered by the lack of a suitable modern analog. We describe calcified cyanobacteria filaments in a modern marine reef setting at Highborne Cay, Bahamas. Our observations and stable isotope data suggest that initial calcification occurs in living cyanobacteria and is photosynthetically induced. A single variety of cyanobacteria, Dichothrix sp., produces calcified filaments. Adjacent cyanobacterial mats form well-laminated stromatolites, rather than calcified filaments, indicating there can be a strong taxonomic control over the mechanism of microbial calcification. Petrographic analyses indicate that the calcified filaments are degraded during early diagenesis and are not present in well-lithified microbialites. The early diagenetic destruction of calcified filaments at Highborne Cay indicates that the absence of calcified cyanobacteria from periods of the Phanerozoic is likely to be caused by low preservation potential as well as inhibited formation.

  2. Synthetic biology of cyanobacteria: unique challenges and opportunities

    PubMed Central

    Berla, Bertram M.; Saha, Rajib; Immethun, Cheryl M.; Maranas, Costas D.; Moon, Tae Seok; Pakrasi, Himadri B.

    2013-01-01

    Photosynthetic organisms, and especially cyanobacteria, hold great promise as sources of renewably-produced fuels, bulk and specialty chemicals, and nutritional products. Synthetic biology tools can help unlock cyanobacteria's potential for these functions, but unfortunately tool development for these organisms has lagged behind that for S. cerevisiae and E. coli. While these organisms may in many cases be more difficult to work with as “chassis” strains for synthetic biology than certain heterotrophs, the unique advantages of autotrophs in biotechnology applications as well as the scientific importance of improved understanding of photosynthesis warrant the development of these systems into something akin to a “green E. coli.” In this review, we highlight unique challenges and opportunities for development of synthetic biology approaches in cyanobacteria. We review classical and recently developed methods for constructing targeted mutants in various cyanobacterial strains, and offer perspective on what genetic tools might most greatly expand the ability to engineer new functions in such strains. Similarly, we review what genetic parts are most needed for the development of cyanobacterial synthetic biology. Finally, we highlight recent methods to construct genome-scale models of cyanobacterial metabolism and to use those models to measure properties of autotrophic metabolism. Throughout this paper, we discuss some of the unique challenges of a diurnal, autotrophic lifestyle along with how the development of synthetic biology and biotechnology in cyanobacteria must fit within those constraints. PMID:24009604

  3. Manipulating cyanobacteria: Spirulina for potential CELSS diet

    NASA Technical Reports Server (NTRS)

    Tadros, Mahasin G.; Smith, Woodrow; Mbuthia, Peter; Joseph, Beverly

    1989-01-01

    Spirulina sp. as a bioregenerative photosynthetic and an edible alga for spacecraft crew in a CELSS, was characterized for the biomass yield in batch cultures, under various environmental conditions. The partitioning of the assimalitory products (proteins, carbohydrates, lipids) were manipulated by varying the environmental growth conditions. Experiments with Spirulina have shown that under stress conditions (i.e., high light 160 uE/sq m/s, temperature 38 C, nitrogen or phosphate limitation; 0.1 M sodium chloride) carbohydrates increased at the expense of proteins. In other experiments, where the growth media were sufficient in nutrients and incubated under optimum growth conditions, the total of the algal could be manipulated by growth conditions. These results support the feasibility of considering Spirulina as a subsystem in CELSS because of the ease with which its nutrient content can be manipulated.

  4. High-sensitivity Stokes spectropolarimetry on cyanobacteria

    NASA Astrophysics Data System (ADS)

    Martin, W. E.; Hesse, E.; Hough, J. H.; Gledhill, T. M.

    2016-02-01

    We investigate the spectral signatures arising from the optical properties of chlorophyll in linear and circularly polarised scattered light from cyanobacteria. We include Stokes scattering coefficient measurements on two cyanobacteria species, Chroococcidiopsis and Synechococcus to a fractional polarisation of ±0.0001 across visible wavelengths. We find that the largest circularly polarised optical signatures from our cyanobacteria samples can be described by optical scattering from spheroidal objects with internal reflections and absorption and, importantly, light scattering from chiral processes is not identifiable in our narrow band light scattering data. We believe previous light scattering measurements attributing chirality effects to cyanobacteria may have been dominated by internal scattering processes.

  5. Fossilized glycolipids reveal past oceanic N2 fixation by heterocystous cyanobacteria

    PubMed Central

    Bauersachs, Thorsten; Speelman, Eveline N.; Hopmans, Ellen C.; Reichart, Gert-Jan; Schouten, Stefan; Damsté, Jaap S. Sinninghe

    2010-01-01

    N2-fixing cyanobacteria play an essential role in sustaining primary productivity in contemporary oceans and freshwater systems. However, the significance of N2-fixing cyanobacteria in past nitrogen cycling is difficult to establish as their preservation potential is relatively poor and specific biological markers are presently lacking. Heterocystous N2-fixing cyanobacteria synthesize unique long-chain glycolipids in the cell envelope covering the heterocyst cell to protect the oxygen-sensitive nitrogenase enzyme. We found that these heterocyst glycolipids are remarkably well preserved in (ancient) lacustrine and marine sediments, unambiguously indicating the (past) presence of N2-fixing heterocystous cyanobacteria. Analysis of Pleistocene sediments of the eastern Mediterranean Sea showed that heterocystous cyanobacteria, likely as epiphytes in symbiosis with planktonic diatoms, were particularly abundant during deposition of sapropels. Eocene Arctic Ocean sediments deposited at a time of large Azolla blooms contained glycolipids typical for heterocystous cyanobacteria presently living in symbiosis with the freshwater fern Azolla, indicating that this symbiosis already existed in that time. Our study thus suggests that heterocystous cyanobacteria played a major role in adding “new” fixed nitrogen to surface waters in past stratified oceans. PMID:20966349

  6. Genetic Instability in Cyanobacteria – An Elephant in the Room?

    PubMed Central

    Jones, Patrik R.

    2014-01-01

    Many research groups are interested in engineering the metabolism of cyanobacteria with the objective to convert solar energy, CO2, and water (perhaps also N2) into commercially valuable products. Toward this objective, many challenges stand in the way before sustainable production can be realized. One of these challenges, potentially, is genetic instability. Although only a handful of reports of this phenomenon are available in the scientific literature, it does appear to be a real issue that so far has not been studied much in cyanobacteria. With this brief perspective, I wish to raise the awareness of this potential issue and hope to inspire future studies on the topic as I believe it will make an important contribution to enabling sustainable large-scale biotechnology in the future using aquatic photobiological microorganisms. PMID:25152885

  7. Dynamics of microcystin production and quantification of potentially toxigenic Microcystis sp. using real-time PCR.

    PubMed

    Srivastava, Ankita; Choi, Gang-Guk; Ahn, Chi-Yong; Oh, Hee-Mock; Ravi, Alok Kumar; Asthana, Ravi Kumar

    2012-03-01

    Cyanobacterial blooms in eutrophied water body are generally composed of various genotypes with or without microcystin-producing genes (mcy gene cluster). Thus there is a need for quantification of potent toxin producing strains. The present study aimed at identifying microcystin variants and its producer strains in Durgakund pond, Varanasi, India, based on quantification of cpcBA-IGS and mcyA (condensation domain) genes using real-time PCR and LC-MS. Increase in microcystin concentrations was correlated with increase in mcyA copy number and the level of pigments (chlorophyll a, phycocyanin and carotenoids). Also, selected environmental factors (water temperature, light irradiance, rainfall, pH, N and P) and the concentration of microcystin variants (MC-LR, -RR and -YR) were also assessed in samples during May 2010 to April 2011 to establish the possible correlation among these parameters. Nutrients favored cyanobacterial bloom but it could not be correlated with the levels of microcystin variants and seemed to be geographically specific. Microcystis sp. dominant in the pond comprised potentially toxigenic cells. The ratio of potentially toxigenic Microcystis sp. to that of total Microcystis sp. ranged from 0% to 14%. Such studies paved the way to identify and quantify the most potent microcystin producer in the tropical aquatic body. PMID:22169661

  8. Pentapeptide Repeat Proteins and Cyanobacteria

    SciTech Connect

    Buchko, Garry W.

    2009-10-16

    Cyanobacteria are unique in many ways and one unusual feature is the presence of a suite of proteins that contain at least one domain with a minimum of eight tandem repeated five-residues (Rfr) of the general consensus sequence A[N/D]LXX. The function of such pentapeptide repeat proteins (PRPs) are still unknown, however, their prevalence in cyanobacteria suggests that they may play some role in the unique biological activities of cyanobacteria. As part of an inter-disciplinary Membrane Biology Grand Challenge at the Environmental Molecular Sciences Laboratory (Pacific Northwest National Laboratory) and Washington University in St. Louis, the genome of Cyanothece 51142 was sequenced and its molecular biology studied with relation to circadian rhythms. The genome of Cyanothece encodes for 35 proteins that contain at least one PRP domain. These proteins range in size from 105 (Cce_3102) to 930 (Cce_2929) kDa with the PRP domains ranging in predicted size from 12 (Cce_1545) to 62 (cce_3979) tandem pentapeptide repeats. Transcriptomic studies with 29 out of the 35 genes showed that at least three of the PRPs in Cyanothece 51142 (cce_0029, cce_3083, and cce_3272) oscillated with repeated periods of light and dark, further supporting a biological function for PRPs. Using X-ray diffraction crystallography, the structure for two pentapeptide repeat proteins from Cyanothece 51142 were determined, cce_1272 (aka Rfr32) and cce_4529 (aka Rfr23). Analysis of their molecular structures suggests that all PRP may share the same structural motif, a novel type of right-handed quadrilateral β-helix, or Rfr-fold, reminiscent of a square tower with four distinct faces. Each pentapeptide repeat occupies one face of the Rfr-fold with four consecutive pentapeptide repeats completing a coil that, in turn, stack upon each other to form “protein skyscrapers”. Details of the structural features of the Rfr-fold are reviewed here together with a discussion for the possible role of end

  9. Anti-infective Natural Products from Cyanobacteria.

    PubMed

    Niedermeyer, Timo Horst Johannes

    2015-10-01

    Cyanobacteria are a promising yet underexplored source for novel natural products with potent biological activities. While predominantly cytotoxic compounds have been isolated from cyanobacteria in the past, there are also a significant number of compounds known that possess anti-infective activities. As the need for novel anti-infective lead compounds is high, this manuscript aims at giving a concise overview on the current knowledge about anti-infective secondary metabolites isolated from cyanobacteria. Antibacterial, antifungal, antiviral, antiprotozoal, and molluscicidal activities are discussed. Covering up to February 2015.

  10. Pattern Formation without Patterning Proteins in Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Allard, Jun; Rutenberg, Andrew

    2006-03-01

    Filaments of cyanobacteria respond to nitrogen starvation by differentiating one cell in ten into a heterocyst, which is devoted to fixing atmospheric nitrogen. This is an example of self-organized pattern formation. We present a dynamical model explaining the initial selection of heterocysts in mutated cyanobacteria that are effectively without normal patterning proteins. Our simulations of this model produce distributions of heterocyst spacings that are consistent with experimental data, and lead to new qualitative predictions on the mechanisms of pattern formation in filamentous cyanobacteria. We discuss possible experimental tests of our results.

  11. Responses to oxidative and heavy metal stresses in cyanobacteria: recent advances.

    PubMed

    Cassier-Chauvat, Corinne; Chauvat, Franck

    2014-12-31

    Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk.

  12. Responses to oxidative and heavy metal stresses in cyanobacteria: recent advances.

    PubMed

    Cassier-Chauvat, Corinne; Chauvat, Franck

    2015-01-01

    Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk. PMID:25561236

  13. Responses to Oxidative and Heavy Metal Stresses in Cyanobacteria: Recent Advances

    PubMed Central

    Cassier-Chauvat, Corinne; Chauvat, Franck

    2014-01-01

    Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk. PMID:25561236

  14. Liberation of ammonia by cyanobacteria

    SciTech Connect

    Newton, J.W.

    1986-04-01

    Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog /sup 14/C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism.

  15. Peroxiredoxins in Plants and Cyanobacteria

    PubMed Central

    2011-01-01

    Abstract Peroxiredoxins (Prx) are central elements of the antioxidant defense system and the dithiol-disulfide redox regulatory network of the plant and cyanobacterial cell. They employ a thiol-based catalytic mechanism to reduce H2O2, alkylhydroperoxide, and peroxinitrite. In plants and cyanobacteria, there exist 2-CysPrx, 1-CysPrx, PrxQ, and type II Prx. Higher plants typically contain at least one plastid 2-CysPrx, one nucleo-cytoplasmic 1-CysPrx, one chloroplast PrxQ, and one each of cytosolic, mitochondrial, and plastidic type II Prx. Cyanobacteria express variable sets of three or more Prxs. The catalytic cycle consists of three steps: (i) peroxidative reduction, (ii) resolving step, and (iii) regeneration using diverse electron donors such as thioredoxins, glutaredoxins, cyclophilins, glutathione, and ascorbic acid. Prx proteins undergo major conformational changes in dependence of their redox state. Thus, they not only modulate cellular reactive oxygen species- and reactive nitrogen species-dependent signaling, but depending on the Prx type they sense the redox state, transmit redox information to binding partners, and function as chaperone. They serve in context of photosynthesis and respiration, but also in metabolism and development of all tissues, for example, in nodules as well as during seed and fruit development. The article surveys the current literature and attempts a mostly comprehensive coverage of present day knowledge and concepts on Prx mechanism, regulation, and function and thus on the whole Prx systems in plants. Antioxid. Redox Signal. 15, 1129–1159. PMID:21194355

  16. Cyanofuels: biofuels from cyanobacteria. Reality and perspectives.

    PubMed

    Sarsekeyeva, Fariza; Zayadan, Bolatkhan K; Usserbaeva, Aizhan; Bedbenov, Vladimir S; Sinetova, Maria A; Los, Dmitry A

    2015-08-01

    Cyanobacteria are represented by a diverse group of microorganisms that, by virtue of being a part of marine and freshwater phytoplankton, significantly contribute to the fixation of atmospheric carbon via photosynthesis. It is assumed that ancient cyanobacteria participated in the formation of earth's oil deposits. Biomass of modern cyanobacteria may be converted into bio-oil by pyrolysis. Modern cyanobacteria grow fast; they do not compete for agricultural lands and resources; they efficiently convert excessive amounts of CO2 into biomass, thus participating in both carbon fixation and organic chemical production. Many cyanobacterial species are easier to genetically manipulate than eukaryotic algae and other photosynthetic organisms. Thus, the cyanobacterial photosynthesis may be directed to produce carbohydrates, fatty acids, or alcohols as renewable sources of biofuels. Here we review the recent achievements in the developments and production of cyanofuels-biofuels produced from cyanobacterial biomass.

  17. INVESTIGATOIN OF CYANOBACTERIA TOXINS IN WATER

    EPA Science Inventory

    Introduction:

    Approximately 80 alkaloid and cyclic peptide toxins produced by various freshwater and marine cyanobacteria (blue-green algae) have been identified and their structures determined. The U. S. Environmental Protection Agency has identified two neurotoxin alkalo...

  18. Identification of Cyanobacteria Populations Using Characteristic Absorbance Spectra

    NASA Astrophysics Data System (ADS)

    Elliott, K.; Kirkpatrick, G.

    2008-12-01

    Cyanobacterial harmful algal blooms (CHABs) are sudden, massive growths of cyanobacteria in bodies of water. They are a particular nuisance in freshwater where they can cause eutrophocation and release toxins into the water. Currently, there is no method for autonomously detecting and identifying cyanobacteria in situ. The BreveBuster---invented by Gary Kirkpatrick at Mote Marine Laboratory---is able to autonomously identify populations of Karenia brevis in the Gulf of Mexico. The BreveBuster takes in a water sample in situ and then measures the absorption spectrum for that sample. The similarity between the water sample's absorption spectrum and the standard absorption spectrum for K. brevis is calculated. We demonstrate in this paper that the BreveBuster can potentially be used to identify and differentiate cyanobacterial species. The absorption spectra of 56 samples of cyanobacteria (from the genera Anabaena, Cylindrospermopsis, Microcystis, and Oscillatoria) were measured by the BreveBuster. Pairwise similarity indices were calculated between each of the 56 absorption spectra and a similarity matrix was constructed. The average similarity between all 56 samples was 0.59. The average similarity among genus samples was 0.74 for Anabaena, 0.73 for Cylindrospermopsis, 0.84 for Microcystis and 0.74 for Oscillatoria. An analysis of similarity confirmed the statistically significant differences between the genera.

  19. Direct Use of Mineral Carbonate for Autotrophy Among Euendolithic Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Guida, B. S.

    2015-12-01

    Cyanobacteria are oxygenic photoautotrophs, and arguably the most important primary producers on the planet, fixing carbon from dissolved inorganic carbon (DIC) in the aquatic environment, and directly from atmospheric CO2 in terrestrial systems. Euendolithic cyanobacteria occupy a very specific niche, inside rocks, which can potentially preclude them from easily accessing those carbon pools, and yet, natural euendolithic communities can support food webs in habitats where they are prominent, such as in marine carbonate platforms and desert carbonate outcrops. In a recently proposed model describing the mechanism of cyanobacterial carbonate boring, we postulated that as the organism dissolves the mineral, liberated CO32- anions will be quickly converted to HCO3- and assimilated directly, making the cyanobacterium independent of external DIC pools for autotrophy. We used natural abundance and tracer stable carbon (13C) isotope analyses accompanied by nanoSIMS imaging in model laboratory systems of cultivated cyanobacteria and in natural mixed communities of marine euendoliths to study the ultimate source of carbon in their biomass. Our results clearly demonstrate that endolithic biomass of these cyanobacteria is significantly derived from mineral carbonate, as opposed to free-living or epilithic biomass, where the source is mixed or coming from the dissolved pool, this holds for model cultures as well as natural communities. In fact, we can increase the lifestyle preference of cultures for endolithic growth versus planktonic or benthic growth, by simply imposing an external DIC limitation in the presence of a carbonate substrate. Our results predict that benthic communities (extant or fossil) that rely heavily on primary production by euendolithic primary producers may show 13C signatures that mimic those of the surrounding carbonate substrate rather than from those of the local seawater.

  20. Forecasting cyanobacteria dominance in Canadian temperate lakes.

    PubMed

    Persaud, Anurani D; Paterson, Andrew M; Dillon, Peter J; Winter, Jennifer G; Palmer, Michelle; Somers, Keith M

    2015-03-15

    Predictive models based on broad scale, spatial surveys typically identify nutrients and climate as the most important predictors of cyanobacteria abundance; however these models generally have low predictive power because at smaller geographic scales numerous other factors may be equally or more important. At the lake level, for example, the ability to forecast cyanobacteria dominance is of tremendous value to lake managers as they can use such models to communicate exposure risks associated with recreational and drinking water use, and possible exposure to algal toxins, in advance of bloom occurrence. We used detailed algal, limnological and meteorological data from two temperate lakes in south-central Ontario, Canada to determine the factors that are closely linked to cyanobacteria dominance, and to develop easy to use models to forecast cyanobacteria biovolume. For Brandy Lake (BL), the strongest and most parsimonious model for forecasting % cyanobacteria biovolume (% CB) included water column stability, hypolimnetic TP, and % cyanobacteria biovolume two weeks prior. For Three Mile Lake (TML), the best model for forecasting % CB included water column stability, hypolimnetic TP concentration, and 7-d mean wind speed. The models for forecasting % CB in BL and TML are fundamentally different in their lag periods (BL = lag 1 model and TML = lag 2 model) and in some predictor variables despite the close proximity of the study lakes. We speculate that three main factors (nutrient concentrations, water transparency and lake morphometry) may have contributed to differences in the models developed, and may account for variation observed in models derived from large spatial surveys. Our results illustrate that while forecast models can be developed to determine when cyanobacteria will dominate within two temperate lakes, the models require detailed, lake-specific calibration to be effective as risk-management tools.

  1. Bryophyte-cyanobacteria associations during primary succession in recently Deglaciated areas of Tierra del Fuego (Chile).

    PubMed

    Arróniz-Crespo, María; Pérez-Ortega, Sergio; De Los Ríos, Asunción; Green, T G Allan; Ochoa-Hueso, Raúl; Casermeiro, Miguel Ángel; de la Cruz, María Teresa; Pintado, Ana; Palacios, David; Rozzi, Ricardo; Tysklind, Niklas; Sancho, Leopoldo G

    2014-01-01

    Bryophyte establishment represents a positive feedback process that enhances soil development in newly exposed terrain. Further, biological nitrogen (N) fixation by cyanobacteria in association with mosses can be an important supply of N to terrestrial ecosystems, however the role of these associations during post-glacial primary succession is not yet fully understood. Here, we analyzed chronosequences in front of two receding glaciers with contrasting climatic conditions (wetter vs drier) at Cordillera Darwin (Tierra del Fuego) and found that most mosses had the capacity to support an epiphytic flora of cyanobacteria and exhibited high rates of N2 fixation. Pioneer moss-cyanobacteria associations showed the highest N2 fixation rates (4.60 and 4.96 µg N g-1 bryo. d-1) very early after glacier retreat (4 and 7 years) which may help accelerate soil development under wetter conditions. In drier climate, N2 fixation on bryophyte-cyanobacteria associations was also high (0.94 and 1.42 µg N g-1 bryo. d-1) but peaked at intermediate-aged sites (26 and 66 years). N2 fixation capacity on bryophytes was primarily driven by epiphytic cyanobacteria abundance rather than community composition. Most liverworts showed low colonization and N2 fixation rates, and mosses did not exhibit consistent differences across life forms and habitat (saxicolous vs terricolous). We also found a clear relationship between cyanobacteria genera and the stages of ecological succession, but no relationship was found with host species identity. Glacier forelands in Tierra del Fuego show fast rates of soil transformation which imply large quantities of N inputs. Our results highlight the potential contribution of bryophyte-cyanobacteria associations to N accumulation during post-glacial primary succession and further describe the factors that drive N2-fixation rates in post-glacial areas with very low N deposition.

  2. Bryophyte-Cyanobacteria Associations during Primary Succession in Recently Deglaciated Areas of Tierra del Fuego (Chile)

    PubMed Central

    Arróniz-Crespo, María; Pérez-Ortega, Sergio; De los Ríos, Asunción; Green, T. G. Allan; Ochoa-Hueso, Raúl; Casermeiro, Miguel Ángel; de la Cruz, María Teresa; Pintado, Ana; Palacios, David; Rozzi, Ricardo; Tysklind, Niklas; Sancho, Leopoldo G.

    2014-01-01

    Bryophyte establishment represents a positive feedback process that enhances soil development in newly exposed terrain. Further, biological nitrogen (N) fixation by cyanobacteria in association with mosses can be an important supply of N to terrestrial ecosystems, however the role of these associations during post-glacial primary succession is not yet fully understood. Here, we analyzed chronosequences in front of two receding glaciers with contrasting climatic conditions (wetter vs drier) at Cordillera Darwin (Tierra del Fuego) and found that most mosses had the capacity to support an epiphytic flora of cyanobacteria and exhibited high rates of N2 fixation. Pioneer moss-cyanobacteria associations showed the highest N2 fixation rates (4.60 and 4.96 µg N g−1 bryo. d−1) very early after glacier retreat (4 and 7 years) which may help accelerate soil development under wetter conditions. In drier climate, N2 fixation on bryophyte-cyanobacteria associations was also high (0.94 and 1.42 µg N g−1 bryo. d−1) but peaked at intermediate-aged sites (26 and 66 years). N2 fixation capacity on bryophytes was primarily driven by epiphytic cyanobacteria abundance rather than community composition. Most liverworts showed low colonization and N2 fixation rates, and mosses did not exhibit consistent differences across life forms and habitat (saxicolous vs terricolous). We also found a clear relationship between cyanobacteria genera and the stages of ecological succession, but no relationship was found with host species identity. Glacier forelands in Tierra del Fuego show fast rates of soil transformation which imply large quantities of N inputs. Our results highlight the potential contribution of bryophyte-cyanobacteria associations to N accumulation during post-glacial primary succession and further describe the factors that drive N2-fixation rates in post-glacial areas with very low N deposition. PMID:24819926

  3. Toward a systems-level understanding of gene regulatory, protein interaction, and metabolic networks in cyanobacteria

    PubMed Central

    Hernández-Prieto, Miguel A.; Semeniuk, Trudi A.; Futschik, Matthias E.

    2014-01-01

    Cyanobacteria are essential primary producers in marine ecosystems, playing an important role in both carbon and nitrogen cycles. In the last decade, various genome sequencing and metagenomic projects have generated large amounts of genetic data for cyanobacteria. This wealth of data provides researchers with a new basis for the study of molecular adaptation, ecology and evolution of cyanobacteria, as well as for developing biotechnological applications. It also facilitates the use of multiplex techniques, i.e., expression profiling by high-throughput technologies such as microarrays, RNA-seq, and proteomics. However, exploration and analysis of these data is challenging, and often requires advanced computational methods. Also, they need to be integrated into our existing framework of knowledge to use them to draw reliable biological conclusions. Here, systems biology provides important tools. Especially, the construction and analysis of molecular networks has emerged as a powerful systems-level framework, with which to integrate such data, and to better understand biological relevant processes in these organisms. In this review, we provide an overview of the advances and experimental approaches undertaken using multiplex data from genomic, transcriptomic, proteomic, and metabolomic studies in cyanobacteria. Furthermore, we summarize currently available web-based tools dedicated to cyanobacteria, i.e., CyanoBase, CyanoEXpress, ProPortal, Cyanorak, CyanoBIKE, and CINPER. Finally, we present a case study for the freshwater model cyanobacteria, Synechocystis sp. PCC6803, to show the power of meta-analysis, and the potential to extrapolate acquired knowledge to the ecologically important marine cyanobacteria genus, Prochlorococcus. PMID:25071821

  4. Toward a systems-level understanding of gene regulatory, protein interaction, and metabolic networks in cyanobacteria.

    PubMed

    Hernández-Prieto, Miguel A; Semeniuk, Trudi A; Futschik, Matthias E

    2014-01-01

    Cyanobacteria are essential primary producers in marine ecosystems, playing an important role in both carbon and nitrogen cycles. In the last decade, various genome sequencing and metagenomic projects have generated large amounts of genetic data for cyanobacteria. This wealth of data provides researchers with a new basis for the study of molecular adaptation, ecology and evolution of cyanobacteria, as well as for developing biotechnological applications. It also facilitates the use of multiplex techniques, i.e., expression profiling by high-throughput technologies such as microarrays, RNA-seq, and proteomics. However, exploration and analysis of these data is challenging, and often requires advanced computational methods. Also, they need to be integrated into our existing framework of knowledge to use them to draw reliable biological conclusions. Here, systems biology provides important tools. Especially, the construction and analysis of molecular networks has emerged as a powerful systems-level framework, with which to integrate such data, and to better understand biological relevant processes in these organisms. In this review, we provide an overview of the advances and experimental approaches undertaken using multiplex data from genomic, transcriptomic, proteomic, and metabolomic studies in cyanobacteria. Furthermore, we summarize currently available web-based tools dedicated to cyanobacteria, i.e., CyanoBase, CyanoEXpress, ProPortal, Cyanorak, CyanoBIKE, and CINPER. Finally, we present a case study for the freshwater model cyanobacteria, Synechocystis sp. PCC6803, to show the power of meta-analysis, and the potential to extrapolate acquired knowledge to the ecologically important marine cyanobacteria genus, Prochlorococcus.

  5. BASIC: Baltic Sea cyanobacteria. An investigation of the structure and dynamics of water blooms of cyanobacteria in the Baltic Sea—responses to a changing environment

    NASA Astrophysics Data System (ADS)

    Stal, Lucas J.; Albertano, Patrizia; Bergman, Birgitta; Bröckel, Klaus von; Gallon, John R.; Hayes, Paul K.; Sivonen, Kaarina; Walsby, Anthony E.

    2003-11-01

    The blooms of cyanobacteria that develop each summer in the Baltic Sea are composed of two functional groups, namely the small-sized picocyanobacteria ( Synechococcus sp.) and the larger, colony-forming, filamentous N 2-fixing cyanobacteria. The former encompassed both red (phycoerythrin-rich) and blue-green (phycocyanin-rich) species. The majority of the picocyanobacteria measured less than 1 μm and this size fraction comprised as much as 80% of the total cyanobacterial biomass and contributed as much as 50% of the total primary production of a cyanobacterial bloom. The picocyanobacteria are incapable of fixing N 2, do not possess gas vesicles and are not toxic. However, a small filamentous Pseudanabaena sp. that could potentially fix N 2 was isolated from the picocyanobacteria fraction. The larger cyanobacteria may form surface scums because they possess gas vesicles that make them buoyant. Although their biomass was less than the picocyanobacteria, they therefore form the more conspicuous and nuisance-forming part of the bloom. The larger cyanobacteria were composed mainly of three different species: Nodularia spumigena, Aphanizomenon flos-aquae and Anabaena sp. These all belong to the heterocystous, N 2-fixing cyanobacteria. N. spumigena and A. flos-aquae were the dominant species; only N. spumigena was toxic. Although individual Nodularia filaments showed a range of different phenotypes, they all belong to one species as judged from 16S rDNA sequencing. Through determination of the genotypes of many individual Nodularia filaments, it was shown that this population was not clonal and that horizontal exchange of genetic information occurs. N. spumigena and A. flos-aquae were different with respect to their photosynthetic and N 2-fixing potentials. Depending on prevailing environmental conditions, these differences would promote the proliferation of one species over the other and hence would determine overall the toxicity of a bloom. Daily integrals of photon

  6. The origin of multicellularity in cyanobacteria

    PubMed Central

    2011-01-01

    Background Cyanobacteria are one of the oldest and morphologically most diverse prokaryotic phyla on our planet. The early development of an oxygen-containing atmosphere approximately 2.45 - 2.22 billion years ago is attributed to the photosynthetic activity of cyanobacteria. Furthermore, they are one of the few prokaryotic phyla where multicellularity has evolved. Understanding when and how multicellularity evolved in these ancient organisms would provide fundamental information on the early history of life and further our knowledge of complex life forms. Results We conducted and compared phylogenetic analyses of 16S rDNA sequences from a large sample of taxa representing the morphological and genetic diversity of cyanobacteria. We reconstructed ancestral character states on 10,000 phylogenetic trees. The results suggest that the majority of extant cyanobacteria descend from multicellular ancestors. Reversals to unicellularity occurred at least 5 times. Multicellularity was established again at least once within a single-celled clade. Comparison to the fossil record supports an early origin of multicellularity, possibly as early as the "Great Oxygenation Event" that occurred 2.45 - 2.22 billion years ago. Conclusions The results indicate that a multicellular morphotype evolved early in the cyanobacterial lineage and was regained at least once after a previous loss. Most of the morphological diversity exhibited in cyanobacteria today —including the majority of single-celled species— arose from ancient multicellular lineages. Multicellularity could have conferred a considerable advantage for exploring new niches and hence facilitated the diversification of new lineages. PMID:21320320

  7. Cyanobacteria and prawn farming in northern New South Wales, Australia--a case study on cyanobacteria diversity and hepatotoxin bioaccumulation

    SciTech Connect

    Kankaanpaeae, Harri T.; Holliday, Jon; Schroeder, Helge; Goddard, Timothy J.; Fister, Richard von; Carmichael, Wayne W

    2005-03-15

    Harmful cyanobacteria pose a hazard to aquatic ecosystems due to toxins (hepatotoxic microcystins, nodularins, and cylindrospermopsin) they produce. The microcystins and nodularins are potent toxins, which are also tumor promoters. The microcystins and nodularins may accumulate into aquatic organisms and be transferred to higher trophic levels, and eventually affect vector animals and consumers. Prawn farming is a rapidly growing industry in Australia. Because information regarding effects of cyanobacteria at prawn farms was lacking, we examined diversity of cyanobacteria and toxin production plus bioaccumulation into black tiger prawns (Penaeus monodon) under both field (northern New South Wales, Australia, December 2001-April 2002) and laboratory conditions. Samples were analyzed for hepatotoxins using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC). The maximum density of cyanobacteria (1 x 10{sup 6} to 4 x 10{sup 6} cells/l) was reached in April. Cyanobacteria encountered were Oscillatoria sp. (up to 4 x 10{sup 6} cells/l), Pseudanabaena sp. (up to 1.8 x 10{sup 6} cells/l), Microcystis sp. (up to 3.5 x 10{sup 4} cells/l), and Aphanocapsa sp. (up to 2 x 10{sup 4} cells/l). An uncommon cyanobacterium, Romeria sp. (up to 2.2 x 10{sup 6} cells/l), was also observed. Contrasting earlier indications, toxic Nodularia spumigena was absent. Despite that both Oscillatoria sp. and Microcystis sp. are potentially hepatotoxic, hepatotoxin levels in phytoplankton samples remained low (up to 0.5-1.2 mg/kg dw; ELISA) in 2001-2002. ELISA was found suitable not only for phytoplankton but prawn tissues as well. Enzymatic pretreatment improved extractability of hepatotoxin from cyanobacteria (nodularin from N. spumigena as an example), but did not generally increase toxin recovery from prawn hepatopancreas. There were slightly increasing hepatotoxin concentrations in prawn hepatopancreas (from 6-20 to 20-80 {mu}g/kg dw; ELISA) during the

  8. Chytrid parasitism facilitates trophic transfer between bloom-forming cyanobacteria and zooplankton (Daphnia)

    PubMed Central

    Agha, Ramsy; Saebelfeld, Manja; Manthey, Christin; Rohrlack, Thomas; Wolinska, Justyna

    2016-01-01

    Parasites are rarely included in food web studies, although they can strongly alter trophic interactions. In aquatic ecosystems, poorly grazed cyanobacteria often dominate phytoplankton communities, leading to the decoupling of primary and secondary production. Here, we addressed the interface between predator-prey and host-parasite interactions by conducting a life-table experiment, in which four Daphnia galeata genotypes were maintained on quantitatively comparable diets consisting of healthy cyanobacteria or cyanobacteria infected by a fungal (chytrid) parasite. In four out of five fitness parameters, at least one Daphnia genotype performed better on parasitised cyanobacteria than in the absence of infection. Further treatments consisting of purified chytrid zoospores and heterotrophic bacteria suspensions established the causes of improved fitness. First, Daphnia feed on chytrid zoospores which trophically upgrade cyanobacterial carbon. Second, an increase in heterotrophic bacterial biomass, promoted by cyanobacterial decay, provides an additional food source for Daphnia. In addition, chytrid infection induces fragmentation of cyanobacterial filaments, which could render cyanobacteria more edible. Our results demonstrate that chytrid parasitism can sustain zooplankton under cyanobacterial bloom conditions, and exemplify the potential of parasites to alter interactions between trophic levels. PMID:27733762

  9. Chytrid parasitism facilitates trophic transfer between bloom-forming cyanobacteria and zooplankton (Daphnia)

    NASA Astrophysics Data System (ADS)

    Agha, Ramsy; Saebelfeld, Manja; Manthey, Christin; Rohrlack, Thomas; Wolinska, Justyna

    2016-10-01

    Parasites are rarely included in food web studies, although they can strongly alter trophic interactions. In aquatic ecosystems, poorly grazed cyanobacteria often dominate phytoplankton communities, leading to the decoupling of primary and secondary production. Here, we addressed the interface between predator-prey and host-parasite interactions by conducting a life-table experiment, in which four Daphnia galeata genotypes were maintained on quantitatively comparable diets consisting of healthy cyanobacteria or cyanobacteria infected by a fungal (chytrid) parasite. In four out of five fitness parameters, at least one Daphnia genotype performed better on parasitised cyanobacteria than in the absence of infection. Further treatments consisting of purified chytrid zoospores and heterotrophic bacteria suspensions established the causes of improved fitness. First, Daphnia feed on chytrid zoospores which trophically upgrade cyanobacterial carbon. Second, an increase in heterotrophic bacterial biomass, promoted by cyanobacterial decay, provides an additional food source for Daphnia. In addition, chytrid infection induces fragmentation of cyanobacterial filaments, which could render cyanobacteria more edible. Our results demonstrate that chytrid parasitism can sustain zooplankton under cyanobacterial bloom conditions, and exemplify the potential of parasites to alter interactions between trophic levels.

  10. Cyanobacteria: A Precious Bio-resource in Agriculture, Ecosystem, and Environmental Sustainability

    PubMed Central

    Singh, Jay Shankar; Kumar, Arun; Rai, Amar N.; Singh, Devendra P.

    2016-01-01

    Keeping in view, the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, synga, and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet. PMID:27148218

  11. Cyanobacteria: A Precious Bio-resource in Agriculture, Ecosystem, and Environmental Sustainability.

    PubMed

    Singh, Jay Shankar; Kumar, Arun; Rai, Amar N; Singh, Devendra P

    2016-01-01

    Keeping in view, the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, synga, and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet. PMID:27148218

  12. Cyanobacteria: A Precious Bio-resource in Agriculture, Ecosystem, and Environmental Sustainability.

    PubMed

    Singh, Jay Shankar; Kumar, Arun; Rai, Amar N; Singh, Devendra P

    2016-01-01

    Keeping in view, the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, synga, and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet.

  13. Color of cyanobacteria: some methodological aspects

    SciTech Connect

    Prieto, Beatriz; Sanmartin, Patricia; Aira, Noelia; Silva, Benita

    2010-04-10

    Although the color of cyanobacteria is a very informative characteristic, no standardized protocol has, so far, been established for defining the color in an objective way, and, therefore, direct comparison of experimental results obtained by different research groups is not possible. In the present study, we used colorimetric measurements and conventional statistical tools to determine the effects on the measurement of the color of cyanobacteria, of the concentration of the microorganisms and their moisture content, as well as of the size of the target area and the minimum number of measurements. It was concluded that the color measurement is affected by every factor studied, but that this can be controlled for by making at least 10 consecutive measurements/9.62 cm{sup 2} at different randomly selected points on the surface of filters completely covered by films of cyanobacteria in which the moisture contents are higher than 50%.

  14. Oxygen relations of nitrogen fixation in cyanobacteria.

    PubMed Central

    Fay, P

    1992-01-01

    The enigmatic coexistence of O2-sensitive nitrogenase and O2-evolving photosynthesis in diazotrophic cyanobacteria has fascinated researchers for over two decades. Research efforts in the past 10 years have revealed a range of O2 sensitivity of nitrogenase in different strains of cyanobacteria and a variety of adaptations for the protection of nitrogenase from damage by both atmospheric and photosynthetic sources of O2. The most complex and apparently most efficient mechanisms for the protection of nitrogenase are incorporated in the heterocysts, the N2-fixing cells of cyanobacteria. Genetic studies indicate that the controls of heterocyst development and nitrogenase synthesis are closely interrelated and that the expression of N2 fixation (nif) genes is regulated by pO2. Images PMID:1620069

  15. Expression of foreign genes in filamentous cyanobacteria

    SciTech Connect

    Kuritz, T.; Wolk, C.P. )

    1993-06-01

    Several advantages make cyanobacteria attractive hosts for biodegradative genes and possibly for other exogenous genes that have practical uses. The authors have obtained expression in Anabaena sp. strain PCC 7120 and Nostoc ellipsosporum of a dechlorination operon, fcbAB, from Arthrobacter globiformis, and have also developed a simple method for qualitative assessment of dechlorination by microorganisms, such as cyanobacteria, whose metabolism is dependent on the presence of chloride in the medium. Transcription of fcbAB under the control of a variety of promoters was monitored by placing luxAB (encoding luciferase) downstream from fcbAB, and by measuring light emission from luciferase. They believe that the system that they have described has value as a means to screen for factors influencing transcription of foreign genes in cyanobacteria.

  16. [Molecular techniques for cyanobacteria detection at Riogrande II and La Fe water reservoirs, Colombia].

    PubMed

    Hurtado-Alarcón, Julio César; Polanía-Vorenberg, Jaime

    2014-03-01

    In lentic water bodies as reservoirs occur eutrophication processes, originated mainly from human activities (i.e. agriculture, animal exploitation). This influx of nutrients in aquatic ecosystems could promote blooms of potentially toxic cyanobacteria. The purpose of this work is to detect the presence of cyanobacteria strains in water samples, using molecular techniques to help in preventive management of reservoirs dedicated to water purification. We used two molecular techniques to detect genes implied with the synthesis of hepatotoxic microcystins from potentially toxic cyanobacteria strains, and to evaluate the molecular diversity of cyanobacteria in water samples from two high-mountain reservoirs used for purification of drinking water for the metropolitan area of Medellin, Colombia. Between 2010-2011 collections of 12 water samples were taken and DNA extraction together with PCR and DGGE analyses where carried out. We amplified 22 sequences between 250-300bp of the genes mcyA and mcyE, and these sequences were related with several strains and cyanobacteria genera accessions from NCBI-GenBank databases. Moreover, sequence amplifications of the 16S small ribosomal RNA subunit - 16S rRNA- between 400-800bp were also performed in order to use them for the DGGE technique. The amplification products of DGGE were set in polyacrilamide gel with posterior denaturing electrophoresis, and the scanned images of the gel bands were analysed with the software GelCompar II. For Riogrande II and La Fe reservoirs we found 35 and 30 different DGGE bands, respectively, as a measurement of molecular diversity in these artificial ecosystems. Here, we demonstrated the utility of two molecular techniques for the detection of genes associated with toxicity and molecular diversity of cyanobacteria in reservoirs destined for drinking water in urban centers. We recommend strongly following with periodically molecular biology studies in these ecosystems combined with limnological and

  17. Microfossils of Cyanobacteria in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.

    2007-01-01

    During the past decade, Environmental and Field Emission Scanning Electron Microscopes have been used at the NASA/Marshall Space Flight Center to investigate freshly fractured interior surfaces of a large number of different types of meteorites. Large, complex, microfossils with clearly recognizable biological affinities have been found embedded in several carbonaceous meteorites. Similar forms were notably absent in all stony and nickel-iron meteorites investigated. The forms encountered are consistent in size and morphology with morphotypes of known genera of Cyanobacteria and microorganisms that are typically encountered in associated benthic prokaryotic mats. Even though many coccoidal and isodiametric filamentous cyanobacteria have a strong morphological convergence with some other spherical and filamentous bacteria and algae, many genera of heteropolar cyanobacteria have distinctive apical and basal regions and cellular differentiation that makes it possible to unambiguously recognize the forms based entirely upon cellular dimensions, filament size and distinctive morphological characteristics. For almost two centuries, these morphological characteristics have historically provided the basis for the systematics and taxonomy of cyanobacteria. This paper presents ESEM and FESEM images of embedded filaments and thick mats found in-situ in the Murchison CM2 and Orgueil cn carbonaceous meteorites. Comparative images are also provided for known genera and species of cyanobacteria and other microbial extremophiles. Energy Dispersive X-ray Spectroscopy (EDS) studies indicate that the meteorite filaments typically exhibit dramatic chemical differentiation with distinctive difference between the possible microfossil and the meteorite matrix in the immediate proximity. Chemical differentiation is also observed within these microstructures with many of the permineralized filaments enveloped within electron transparent carbonaceous sheaths. Elemental distributions of

  18. Mesoproterozoic Archaeoellipsoides: akinetes of heterocystous cyanobacteria

    NASA Technical Reports Server (NTRS)

    Golubic, S.; Sergeev, V. N.; Knoll, A. H.

    1995-01-01

    The genus Archaeoellipsoides Horodyski & Donaldson comprises large (up to 135 micrometers long) ellipsoidal and rod-shaped microfossils commonly found in silicified peritidal carbonates of Mesoproterozoic age. Based on morphometric and sedimentary comparisons with the akinetes of modern bloom-forming Anabaena species, Archaeoellipsoides is interpreted as the fossilized remains of akinetes produced by planktic heterocystous cyanobacteria. These fossils set a minimum date for the evolution of derived cyanobacteria capable of marked cell differentiation, and they corroborate geochemical evidence indicating that atmospheric oxygen levels were well above 1% of present day levels 1,500 million years ago.

  19. Biogenic C-doped titania templated by cyanobacteria for visible-light photocatalytic degradation of Rhodamine B.

    PubMed

    He, Jiao; Zi, Guoli; Yan, Zhiying; Li, Yongli; Xie, Jiao; Duan, Deliang; Chen, Yongjuan; Wang, Jiaqiang

    2014-05-01

    Cyanobacteria, which occurred in eutrophic water harvest solar light to carry out photosynthesis with high efficiency. In this work, cyanobacteria (Microcystis sp.) were used as biotemplate to synthesize titania structure. The synthesized titania sample had similar morphology to that of the original template in spite of the fragile unicellular structures and extremely high water content of cyanobacterial cells. Incorporation of biogenic C, as well as the morphology inherited from biotemplate improved visible-light absorbance of the titania structure. The sample exhibited higher visible-light photocatalytic activity than commercial titania photocatalyst Degussa P25 for Rhodamine B (RhB) degradation. Compared with those C-doped titania photocatalysts prepared by other methods, cyanobacteria templated titania photocatalyst offer some potential for competitive advantages. The reported strategy opened up a new use for the cyanobacteria. It could also be used for titania in applications such as treatment of polluted water, dye-sensitized solar cells, or other regions.

  20. Cyanobacteria drive community composition and functionality in rock-soil interface communities.

    PubMed

    Valverde, Angel; Makhalanyane, Thulani P; Seely, Mary; Cowan, Don A

    2015-02-01

    Most ecological research on hypoliths, significant primary producers in hyperarid deserts, has focused on the diversity of individual groups of microbes (i.e. bacteria). However, microbial communities are inherently complex, and the interactions between cyanobacteria, heterotrophic bacteria, protista and metazoa are likely to be very important for ecosystem functioning. Cyanobacterial and heterotrophic bacterial communities were analysed by pyrosequencing, while metazoan and protistan communities were assessed by T-RFLP analysis. Microbial functionality was estimated using carbon substrate utilization. Cyanobacterial community composition was significant in shaping community structure and function in hypoliths. Ecological network analysis showed that most significant co-occurrences were positive, representing potential synergistic interactions. There were several highly interconnected associations (modules), and specific cyanobacteria were important in driving the modular structure of hypolithic networks. Together, our results suggest that hypolithic cyanobacteria have strong effects on higher trophic levels and ecosystem functioning.

  1. Description of new filamentous toxic Cyanobacteria (Oscillatoriales) colonizing the sulfidic periphyton mat in marine mangroves.

    PubMed

    Guidi-Rontani, Chantal; Jean, Maïtena R N; Gonzalez-Rizzo, Silvina; Bolte-Kluge, Susanne; Gros, Olivier

    2014-10-01

    In this multidisciplinary study, we combined morphological, physiological, and phylogenetic approaches to identify three dominant water bloom-forming Cyanobacteria in a tropical marine mangrove in Guadeloupe (French West Indies). Phylogenetic analysis based on 16S rRNA gene sequences place these marine Cyanobacteria in the genera Oscillatoria (Oscillatoria sp. clone gwada, strain OG) or Planktothricoides ('Candidatus Planktothricoides niger' strain OB and 'Candidatus Planktothricoides rosea' strain OP; both provisionally novel species within the genus Planktothricoides). Bioassays showed that 'Candidatus Planktothricoides niger' and 'Candidatus Planktothricoides rosea' are toxin-producing organisms. This is the first report of the characterization of Cyanobacteria colonizing periphyton mats of a tropical marine mangrove. We describe two novel benthic marine species and provide new insight into Oscillatoriaceae and their potential role in marine sulfide-rich environments such as mangroves.

  2. Global warming and hepatotoxin production by cyanobacteria: what can we learn from experiments?

    PubMed

    El-Shehawy, Rehab; Gorokhova, Elena; Fernández-Piñas, Francisca; del Campo, Francisca F

    2012-04-01

    Global temperature is expected to rise throughout this century, and blooms of cyanobacteria in lakes and estuaries are predicted to increase with the current level of global warming. The potential environmental, economic and sanitation repercussions of these blooms have attracted considerable attention among the world's scientific communities, water management agencies and general public. Of particular concern is the worldwide occurrence of hepatotoxic cyanobacteria posing a serious threat to global public health. Here, we highlight plausible effects of global warming on physiological and molecular changes in these cyanobacteria and resulting effects on hepatotoxin production. We also emphasize the importance of understanding the natural biological function(s) of hepatotoxins, various mechanisms governing their synthesis, and climate-driven changes in food-web interactions, if we are to predict consequences of the current and projected levels of global warming for production and accumulation of hepatotoxins in aquatic ecosystems.

  3. Natural products from cyanobacteria: Exploiting a new source for drug discovery.

    PubMed

    Sielaff, Heike; Christiansen, Guntram; Schwecke, Torsten

    2006-02-01

    In the 1990s, the pharmaceutical industry shifted its focus to a combinatorial chemistry approach to fill drug-discovery pipelines; however, more recently there has been renewed interest in natural products as sources of lead compounds. Cyanobacteria are prolific producers of natural products displaying enormous chemical diversity, yet, until recently, exploitation of the genera was hampered by a number of issues related to their handling. With most of these problems now resolved, cyanobacteria have the potential to expand the variety of natural products obtained from microorganisms. The relative disregard in the past of cyanobacteria compared with other microbial sources of natural products, as well as the huge chemical diversity and biological activities of their products, recommend them as an attractive source of novel drugs for use in diverse therapeutic areas.

  4. An efficient DNA isolation protocol for filamentous cyanobacteria of the genus Arthrospira.

    PubMed

    Morin, Nicolas; Vallaeys, Tatiana; Hendrickx, Larissa; Natalie, Leys; Wilmotte, Annick

    2010-02-01

    Thanks to their photosynthetic and nutritive properties, cyanobacteria of the Arthrospira genus are of interest as food supplements, as efficient oxygen producing life support system organisms for manned space flight, and for the production of biofuels. Despite these potential valuable applications, full genome sequences and genetic information in general on Arthrospira remain scarce. This is mainly due to the difficulty to extract sufficient high molecular weight nucleic acids from these filamentous cyanobacteria. In this article, an efficient and reproducible DNA extraction procedure for cyanobacteria of the genus Arthrospira was developed. The method is based on the combination of a soft mechanical lysis with enzymatic disruption of the cell wall. The comparison with other extraction protocols clearly indicates that this optimised method allows the recovery of a larger amount of DNA. Furthermore, the extracted DNA presents a high molecular weight, a reduced degradation and an excellent overall quality. It can be directly used for molecular biology purposes such as PCR, and clone library construction.

  5. One health and cyanobacteria in freshwater systems: animal illnesses and deaths are sentinel events for human health risks.

    PubMed

    Hilborn, Elizabeth D; Beasley, Val R

    2015-04-20

    Harmful cyanobacterial blooms have adversely impacted human and animal health for thousands of years. Recently, the health impacts of harmful cyanobacteria blooms are becoming more frequently detected and reported. However, reports of human and animal illnesses or deaths associated with harmful cyanobacteria blooms tend to be investigated and reported separately. Consequently, professionals working in human or in animal health do not always communicate findings related to these events with one another. Using the One Health concept of integration and collaboration among health disciplines, we systematically review the existing literature to discover where harmful cyanobacteria-associated animal illnesses and deaths have served as sentinel events to warn of potential human health risks. We find that illnesses or deaths among livestock, dogs and fish are all potentially useful as sentinel events for the presence of harmful cyanobacteria that may impact human health. We also describe ways to enhance the value of reports of cyanobacteria-associated illnesses and deaths in animals to protect human health. Efficient monitoring of environmental and animal health in a One Health collaborative framework can provide vital warnings of cyanobacteria-associated human health risks.

  6. One Health and Cyanobacteria in Freshwater Systems: Animal Illnesses and Deaths Are Sentinel Events for Human Health Risks

    PubMed Central

    Hilborn, Elizabeth D.; Beasley, Val R.

    2015-01-01

    Harmful cyanobacterial blooms have adversely impacted human and animal health for thousands of years. Recently, the health impacts of harmful cyanobacteria blooms are becoming more frequently detected and reported. However, reports of human and animal illnesses or deaths associated with harmful cyanobacteria blooms tend to be investigated and reported separately. Consequently, professionals working in human or in animal health do not always communicate findings related to these events with one another. Using the One Health concept of integration and collaboration among health disciplines, we systematically review the existing literature to discover where harmful cyanobacteria-associated animal illnesses and deaths have served as sentinel events to warn of potential human health risks. We find that illnesses or deaths among livestock, dogs and fish are all potentially useful as sentinel events for the presence of harmful cyanobacteria that may impact human health. We also describe ways to enhance the value of reports of cyanobacteria-associated illnesses and deaths in animals to protect human health. Efficient monitoring of environmental and animal health in a One Health collaborative framework can provide vital warnings of cyanobacteria-associated human health risks. PMID:25903764

  7. Tiny Microbes with a Big Impact: The Role of Cyanobacteria and Their Metabolites in Shaping Our Future

    PubMed Central

    Mazard, Sophie; Penesyan, Anahit; Ostrowski, Martin; Paulsen, Ian T.; Egan, Suhelen

    2016-01-01

    Cyanobacteria are among the first microorganisms to have inhabited the Earth. Throughout the last few billion years, they have played a major role in shaping the Earth as the planet we live in, and they continue to play a significant role in our everyday lives. Besides being an essential source of atmospheric oxygen, marine cyanobacteria are prolific secondary metabolite producers, often despite the exceptionally small genomes. Secondary metabolites produced by these organisms are diverse and complex; these include compounds, such as pigments and fluorescent dyes, as well as biologically-active compounds with a particular interest for the pharmaceutical industry. Cyanobacteria are currently regarded as an important source of nutrients and biofuels and form an integral part of novel innovative energy-efficient designs. Being autotrophic organisms, cyanobacteria are well suited for large-scale biotechnological applications due to the low requirements for organic nutrients. Recent advances in molecular biology techniques have considerably enhanced the potential for industries to optimize the production of cyanobacteria secondary metabolites with desired functions. This manuscript reviews the environmental role of marine cyanobacteria with a particular focus on their secondary metabolites and discusses current and future developments in both the production of desired cyanobacterial metabolites and their potential uses in future innovative projects. PMID:27196915

  8. Tiny Microbes with a Big Impact: The Role of Cyanobacteria and Their Metabolites in Shaping Our Future.

    PubMed

    Mazard, Sophie; Penesyan, Anahit; Ostrowski, Martin; Paulsen, Ian T; Egan, Suhelen

    2016-05-01

    Cyanobacteria are among the first microorganisms to have inhabited the Earth. Throughout the last few billion years, they have played a major role in shaping the Earth as the planet we live in, and they continue to play a significant role in our everyday lives. Besides being an essential source of atmospheric oxygen, marine cyanobacteria are prolific secondary metabolite producers, often despite the exceptionally small genomes. Secondary metabolites produced by these organisms are diverse and complex; these include compounds, such as pigments and fluorescent dyes, as well as biologically-active compounds with a particular interest for the pharmaceutical industry. Cyanobacteria are currently regarded as an important source of nutrients and biofuels and form an integral part of novel innovative energy-efficient designs. Being autotrophic organisms, cyanobacteria are well suited for large-scale biotechnological applications due to the low requirements for organic nutrients. Recent advances in molecular biology techniques have considerably enhanced the potential for industries to optimize the production of cyanobacteria secondary metabolites with desired functions. This manuscript reviews the environmental role of marine cyanobacteria with a particular focus on their secondary metabolites and discusses current and future developments in both the production of desired cyanobacterial metabolites and their potential uses in future innovative projects. PMID:27196915

  9. Siderophilic Cyanobacteria: Implications for Early Earth.

    NASA Technical Reports Server (NTRS)

    Brown, I. I.; Mummey, D.; Sarkisova, S.; Shen, G.; Bryant, D. A.; Lindsay, J.; Garrison, D.; McKay, D. S.

    2006-01-01

    Of all extant environs, iron-depositing hot springs (IDHS) may exhibit the greatest similarity to late Precambrian shallow warm oceans in regards to temperature, O2 gradients and dissolved iron and H2S concentrations. Despite the insights into the ecology, evolutionary biology, paleogeobiochemistry, and astrobiology examination of IDHS could potentially provide, very few studies dedicated to the physiology and diversity of cyanobacteria (CB) inhabiting IDHS have been conducted. Results. Here we describe the phylogeny, physiology, ultrastructure and biogeochemical activity of several recent CB isolates from two different greater Yellowstone area IDHS, LaDuke and Chocolate Pots. Phylogenetic analysis of 16S rRNA genes indicated that 6 of 12 new isolates examined couldn't be placed within established CB genera. Some of the isolates exhibited pronounced requirements for elevated iron concentrations, with maximum growth rates observed when 0.4-1 mM Fe(3+) was present in the media. In light of "typical" CB iron requirements, our results indicate that elevated iron likely represents a salient factor selecting for "siderophilicM CB species in IDHS. A universal feature of our new isolates is their ability to produce thick EPS layers in which iron accumulates resulting in the generation of well preserved signatures. In parallel, siderophilic CB show enhanced ability to etch the analogs of iron-rich lunar regolith minerals and impact glasses. Despite that iron deposition by CB is not well understood mechanistically, we recently obtained evidence that the PS I:PS II ratio is higher in one of our isolates than for other CB. Although still preliminary, this finding is in direct support of the Y. Cohen hypothesis that PSI can directly oxidize Fe(2+). Conclusion. Our results may have implications for factors driving CB evolutionary relationships and biogeochemical processes on early Earth and probably Mars.

  10. Stable bio-oil production from proteinaceous cyanobacteria: tail gas reactive pyrolysis of spirulina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pyrolysis of Spirulina, a cyanobacteria with high levels of protein (74 wt %) and low levels of lipid (0.8 wt %) content, has the potential to produce fuels and platform chemicals that differ from those produced from lignocellulosic materials. The yields and product distribution from fluidized-bed p...

  11. Optical researches for cyanobacteria bloom monitoring in Curonian Lagoon

    NASA Astrophysics Data System (ADS)

    Shirshin, Evgeny A.; Budylin, Gleb B.; Yakimov, Boris P.; Voloshina, Olga V.; Karabashev, Genrik S.; Evdoshenko, Marina A.; Fadeev, Victor V.

    2016-04-01

    Cyanobacteria bloom is a great ecological problem of Curonian Lagoon and Baltic Sea. The development of novel methods for the on-line control of cyanobacteria concentration and, moreover, for prediction of bloom spreading is of interest for monitoring the state of ecosystem. Here, we report the results of the joint application of hyperspectral measurements and remote sensing of Curonian Lagoon in July 2015 aimed at the assessment of cyanobacteria communities. We show that hyperspectral data allow on-line detection and qualitative estimation of cyanobacteria concentration, while the remote sensing data indicate the possibility of cyanobacteria bloom detection using the spectral features of upwelling irradiation.

  12. Methods to detect cyanobacteria and their toxins in the environment.

    PubMed

    Moreira, Cristiana; Ramos, Vitor; Azevedo, Joana; Vasconcelos, Vitor

    2014-10-01

    Cyanobacteria blooms are since early times a cause for environmental concern because of their negative impact through the release of odors, water discoloration, and more dangerously through the release of toxic compounds (i.e. the cyanotoxins) that can affect both human and animal welfare. Surveillance of the aquatic ecosystems is therefore obligatory, and methods to achieve such require a prompt answer not only regarding the species that are producing the blooms but also the cyanotoxins that are being produced and/or released. Moreover, besides this well-known source of possible intoxication, it has been demonstrated the existence of several other potential routes of exposure, either for humans or other biota such as through food additives and in terrestrial environments (in plants, lichens, biological soil crusts) and the recognition of their harmful impact on less studied ecosystems (e.g. coral reefs). Nowadays, the most frequent approaches to detect toxic cyanobacteria and/or their toxins are the chemical-, biochemical-, and molecular-based methods. Above their particular characteristics and possible applications, they all bring to the environmental monitoring several aspects that are needed to be discussed and scrutinized. The end outcome of this review will be to provide newer insights and recommendations regarding the methods needed to apply in an environmental risk assessment program. Therefore, a current state of the knowledge concerning the three methodological approaches will be presented, while highlighting positive and negative aspects of each of those methods within the purpose of monitoring or studying cyanobacteria and their toxins in the environment.

  13. Agencies collaborate, develop a cyanobacteria assessment network

    USGS Publications Warehouse

    Schaeffer, Blake A.; Loftin, Keith A.; Stumpf, Richard P.; Werdell, P. Jeremy

    2015-01-01

    Satellite remote sensing tools may enable policy makers and environmental managers to assess the sustainability of watershed ecosystems and the services they provide, now and in the future. Satellite technology allows us to develop early-warning indicators of cyanobacteria blooms at the local scale while maintaining continuous national coverage.

  14. Endosymbiotic heterocystous cyanobacteria synthesize different heterocyst glycolipids than free-living heterocystous cyanobacteria.

    PubMed

    Schouten, Stefan; Villareal, Tracy A; Hopmans, Ellen C; Mets, Anchelique; Swanson, Kathleen M; Sinninghe Damsté, Jaap S

    2013-01-01

    The heterocysts of limnetic nitrogen-fixing filamentous cyanobacteria contain unique glycolipids in their cell wall that create the distinctive gas impermeability of the heterocyst cell wall as well as serve as biomarker lipids for these microbes. It has been assumed that marine free-living and endosymbiotic cyanobacteria synthesize the same glycolipids although they have not been investigated in any detail. Here we report the glycolipid composition of several marine free-living heterocystous cyanobacteria as well as the heterocystous endosymbiont Richelia intracellularis found in the biogeochemically important diatoms Hemiaulus hauckii and Hemiaulus membranaceus. In the marine cyanobacteria Nostoc muscorum and Calothrix sp., we detected the same glycolipids as found in freshwater representatives of these genera. However, we did not detect these glycolipids in the Hemiaulus-Richelia association. Instead, we identified glycolipids which comprised a C₅ sugar, ribose, rather than the C₆ sugars normally encountered in glycolipids of free-living cyanobacteria. In addition, the glycolipids had slightly longer chain lengths (C₃₀ and C₃₂ versus C₂₆ and C₂₈) in the aglycone moiety. The different glycolipid composition of the marine endosymbotic heterocystous cyanobacteria compared to their free-living counterparts may be an adaptation to the high intracellular O₂ concentrations within their host. These glycolipids may provide unique tracers for the presence of these microbes in marine environments and permit exploration of the evolutionary origins of these symbioses.

  15. Climate change: links to global expansion of harmful cyanobacteria.

    PubMed

    Paerl, Hans W; Paul, Valerie J

    2012-04-01

    Cyanobacteria are the Earth's oldest (∼3.5 bya) oxygen evolving organisms, and they have had major impacts on shaping our modern-day biosphere. Conversely, biospheric environmental perturbations, including nutrient enrichment and climatic changes (e.g. global warming, hydrologic changes, increased frequencies and intensities of tropical cyclones, more intense and persistent droughts), strongly affect cyanobacterial growth and bloom potentials in freshwater and marine ecosystems. We examined human and climatic controls on harmful (toxic, hypoxia-generating, food web disrupting) bloom-forming cyanobacteria (CyanoHABs) along the freshwater to marine continuum. These changes may act synergistically to promote cyanobacterial dominance and persistence. This synergy is a formidable challenge to water quality, water supply and fisheries managers, because bloom potentials and controls may be altered in response to contemporaneous changes in thermal and hydrologic regimes. In inland waters, hydrologic modifications, including enhanced vertical mixing and, if water supplies permit, increased flushing (reducing residence time) will likely be needed in systems where nutrient input reductions are neither feasible nor possible. Successful control of CyanoHABs by grazers is unlikely except in specific cases. Overall, stricter nutrient management will likely be the most feasible and practical approach to long-term CyanoHAB control in a warmer, stormier and more extreme world.

  16. Iron-Tolerant Cyanobacteria: Ecophysiology and Fingerprinting

    NASA Technical Reports Server (NTRS)

    Brown, I. I.; Mummey, D.; Lindsey, J.; McKay, D. S.

    2006-01-01

    Although the iron-dependent physiology of marine and freshwater cyanobacterial strains has been the focus of extensive study, very few studies dedicated to the physiology and diversity of cyanobacteria inhabiting iron-depositing hot springs have been conducted. One of the few studies that have been conducted [B. Pierson, 1999] found that cyanobacterial members of iron depositing bacterial mat communities might increase the rate of iron oxidation in situ and that ferrous iron concentrations up to 1 mM significantly stimulated light dependent consumption of bicarbonate, suggesting a specific role for elevated iron in photosynthesis of cyanobacteria inhabiting iron-depositing hot springs. Our recent studies pertaining to the diversity and physiology of cyanobacteria populating iron-depositing hot springs in Great Yellowstone area (Western USA) indicated a number of different isolates exhibiting elevated tolerance to Fe(3+) (up to 1 mM). Moreover, stimulation of growth was observed with increased Fe(3+) (0.02-0.4 mM). Molecular fingerprinting of unialgal isolates revealed a new cyanobacterial genus and species Chroogloeocystis siderophila, an unicellular cyanobacterium with significant EPS sheath harboring colloidal Fe(3+) from iron enriched media. Our preliminary data suggest that some filamentous species of iron-tolerant cyanobacteria are capable of exocytosis of iron precipitated in cytoplasm. Prior to 2.4 Ga global oceans were likely significantly enriched in soluble iron [Lindsay et al, 2003], conditions which are not conducive to growth of most contemporary oxygenic cyanobacteria. Thus, iron-tolerant CB may have played important physiological and evolutionary roles in Earths history.

  17. Grazing livestock are exposed to terrestrial cyanobacteria.

    PubMed

    McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A

    2015-02-25

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.

  18. Biofilm formation and indole-3-acetic acid production by two rhizospheric unicellular cyanobacteria.

    PubMed

    Ahmed, Mehboob; Stal, Lucas J; Hasnain, Shahida

    2014-08-01

    Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants.

  19. Biofilm formation and indole-3-acetic acid production by two rhizospheric unicellular cyanobacteria.

    PubMed

    Ahmed, Mehboob; Stal, Lucas J; Hasnain, Shahida

    2014-08-01

    Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants. PMID:24705871

  20. Bioinformatic analysis of the distribution of inorganic carbon transporters and prospective targets for bioengineering to increase Ci uptake by cyanobacteria.

    PubMed

    Gaudana, Sandeep B; Zarzycki, Jan; Moparthi, Vamsi K; Kerfeld, Cheryl A

    2015-10-01

    Cyanobacteria have evolved a carbon-concentrating mechanism (CCM) which has enabled them to inhabit diverse environments encompassing a range of inorganic carbon (Ci: [Formula: see text] and CO2) concentrations. Several uptake systems facilitate inorganic carbon accumulation in the cell, which can in turn be fixed by ribulose 1,5-bisphosphate carboxylase/oxygenase. Here we survey the distribution of genes encoding known Ci uptake systems in cyanobacterial genomes and, using a pfam- and gene context-based approach, identify in the marine (alpha) cyanobacteria a heretofore unrecognized number of putative counterparts to the well-known Ci transporters of beta cyanobacteria. In addition, our analysis shows that there is a huge repertoire of transport systems in cyanobacteria of unknown function, many with homology to characterized Ci transporters. These can be viewed as prospective targets for conversion into ancillary Ci transporters through bioengineering. Increasing intracellular Ci concentration coupled with efforts to increase carbon fixation will be beneficial for the downstream conversion of fixed carbon into value-added products including biofuels. In addition to CCM transporter homologs, we also survey the occurrence of rhodopsin homologs in cyanobacteria, including bacteriorhodopsin, a class of retinal-binding, light-activated proton pumps. Because they are light driven and because of the apparent ease of altering their ion selectivity, we use this as an example of re-purposing an endogenous transporter for the augmentation of Ci uptake by cyanobacteria and potentially chloroplasts.

  1. Detection of the enzymatically-active polyhydroxyalkanoate synthase subunit gene, phaC, in cyanobacteria via colony PCR.

    PubMed

    Lane, Courtney E; Benton, Michael G

    2015-12-01

    A colony PCR-based assay was developed to rapidly determine if a cyanobacterium of interest contains the requisite genetic material, the PHA synthase PhaC subunit, to produce polyhydroxyalkanoates (PHAs). The test is both high throughput and robust, owing to an extensive sequence analysis of cyanobacteria PHA synthases. The assay uses a single detection primer set and a single reaction condition across multiple cyanobacteria strains to produce an easily detectable positive result - amplification via PCR as evidenced by a band in electrophoresis. In order to demonstrate the potential of the presence of phaC as an indicator of a cyanobacteria's PHA accumulation capabilities, the ability to produce PHA was assessed for five cyanobacteria with a traditional in vivo PHA granule staining using an oxazine dye. The confirmed in vivo staining results were then compared to the PCR-based assay results and found to be in agreement. The colony PCR assay was capable of successfully detecting the phaC gene in all six of the diverse cyanobacteria tested which possessed the gene, while exhibiting no undesired product formation across the nine total cyanobacteria strains tested. The colony PCR quick prep provides sufficient usable DNA template such that this assay could be readily expanded to assess multiple genes of interest simultaneously.

  2. Structural Diversity of Bacterial Communities Associated with Bloom-Forming Freshwater Cyanobacteria Differs According to the Cyanobacterial Genus

    PubMed Central

    Louati, Imen; Pascault, Noémie; Debroas, Didier; Bernard, Cécile; Humbert, Jean-François; Leloup, Julie

    2015-01-01

    The factors and processes driving cyanobacterial blooms in eutrophic freshwater ecosystems have been extensively studied in the past decade. A growing number of these studies concern the direct or indirect interactions between cyanobacteria and heterotrophic bacteria. The presence of bacteria that are directly attached or immediately adjacent to cyanobacterial cells suggests that intense nutrient exchanges occur between these microorganisms. In order to determine if there is a specific association between cyanobacteria and bacteria, we compared the bacterial community composition during two cyanobacteria blooms of Anabaena (filamentous and N2-fixing) and Microcystis (colonial and non-N2 fixing) that occurred successively within the same lake. Using high-throughput sequencing, we revealed a clear distinction between associated and free-living communities and between cyanobacterial genera. The interactions between cyanobacteria and bacteria appeared to be based on dissolved organic matter degradation and on N recycling, both for N2-fixing and non N2-fixing cyanobacteria. Thus, the genus and potentially the species of cyanobacteria and its metabolic capacities appeared to select for the bacterial community in the phycosphere. PMID:26579722

  3. Prospective study of acute health effects in relation to exposure to cyanobacteria.

    PubMed

    Lévesque, Benoît; Gervais, Marie-Christine; Chevalier, Pierre; Gauvin, Denis; Anassour-Laouan-Sidi, Elhadji; Gingras, Suzanne; Fortin, Nathalie; Brisson, Geneviève; Greer, Charles; Bird, David

    2014-01-01

    We conducted a study to investigate the relationship between exposure to cyanobacteria and microcystins and the incidence of symptoms in humans living in close proximity to lakes affected by cyanobacteria. The design was a prospective study of residents living around three lakes (Canada), one of which has a water treatment plant supplying potable water to local residents. Participants had to keep a daily journal of symptoms and record contact (full or limited) with the water body. Samples were collected to document cyanobacteria and microcystin concentrations. Symptoms potentially associated with cyanobacteria (gastrointestinal: 2 indices (GI1: diarrhea or abdominal pain or nausea or vomiting; GI2: diarrhea or vomiting or [nausea and fever] or [abdominal cramps and fever]); upper and lower respiratory tract; eye; ear; skin; muscle pain; headaches; mouth ulcers) were examined in relation with exposure to cyanobacteria and microcystin by using Poisson regression. Only gastrointestinal symptoms were associated with recreational contact. Globally, there was a significant increase in adjusted relative risk (RR) with higher cyanobacterial cell counts for GI2 (<20,000 cells/mL: RR=1.52, 95% CI=0.65-3.51; 20,000-100,000 cells/mL: RR=2.71, 95% CI=1.02-7.16; >100,000 cells/mL: RR=3.28, 95% CI=1.69-6.37, p-trend=0.001). In participants who received their drinking water supply from a plant whose source was contaminated by cyanobacteria, an increase in muscle pain (RR=5.16; 95% CI=2.93-9.07) and gastrointestinal (GI1: RR=3.87; 95% CI=1.62-9.21; GI2: RR=2.84; 95% CI=0.82-9.79), skin (RR=2.65; 95% CI=1.09-6.44) and ear symptoms (RR=6.10; 95% CI=2.48-15.03) was observed. The population should be made aware of the risks of gastrointestinal symptoms associated with contact (full or limited) with cyanobacteria. A risk management plan is needed for water treatment plants that draw their water from a source contaminated with cyanobacteria.

  4. Fatty acid production in genetically modified cyanobacteria

    PubMed Central

    Liu, Xinyao; Sheng, Jie; Curtiss III, Roy

    2011-01-01

    To avoid costly biomass recovery in photosynthetic microbial biofuel production, we genetically modified cyanobacteria to produce and secrete fatty acids. Starting with introducing an acyl–acyl carrier protein thioesterase gene, we made six successive generations of genetic modifications of cyanobacterium Synechocystis sp. PCC6803 wild type (SD100). The fatty acid secretion yield was increased to 197 ± 14 mg/L of culture in one improved strain at a cell density of 1.0 × 109 cells/mL by adding codon-optimized thioesterase genes and weakening polar cell wall layers. Although these strains exhibited damaged cell membranes at low cell densities, they grew more rapidly at high cell densities in late exponential and stationary phase and exhibited less cell damage than cells in wild-type cultures. Our results suggest that fatty acid secreting cyanobacteria are a promising technology for renewable biofuel production. PMID:21482809

  5. Analysis of photosystem II biogenesis in cyanobacteria.

    PubMed

    Heinz, Steffen; Liauw, Pasqual; Nickelsen, Jörg; Nowaczyk, Marc

    2016-03-01

    Photosystem II (PSII), a large multisubunit membrane protein complex found in the thylakoid membranes of cyanobacteria, algae and plants, catalyzes light-driven oxygen evolution from water and reduction of plastoquinone. Biogenesis of PSII requires coordinated assembly of at least 20 protein subunits, as well as incorporation of various organic and inorganic cofactors. The stepwise assembly process is facilitated by numerous protein factors that have been identified in recent years. Further analysis of this process requires the development or refinement of specific methods for the identification of novel assembly factors and, in particular, elucidation of the unique role of each. Here we summarize current knowledge of PSII biogenesis in cyanobacteria, focusing primarily on the impact of methodological advances and innovations. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux.

  6. [Morphogenesis in a community of filamentous cyanobacteria].

    PubMed

    Sumina, E L; Sumin, D L

    2013-01-01

    Reversible differentiation was experimentally discovered in a community of modern filamentous cyanobacteria Oscillatoria terebriformis. Splitting of the initially uniform community into differentiated parts (strands, multiradiate aggregates, networks, etc.) occurs only for the duration of a function facilitating the activity of this community as an integral unit. The structures are formed as a result of regrouping of the filaments, without their specialization. A morphologically regulatory system (polygonal network) was found to develop under the impact of extreme factors. The levels of structural organization of filamentous cyanobacteria and multicellular eukaryotes were compared (individual cells in a filament--cell organelles; filaments--individual cells; community--organism), and the similarities and differences in morphogenesis of these groups were analyzed using the data on the embryonic regulation in multicellular eukaryotes. Spatial information in morphogenesis was shown to result not from direct realization of an inherited program but is created by the elements of integral organisms (cells and filaments) in the course of development.

  7. [Cyanobacteria as indicators of organic contamination].

    PubMed

    Peinador, M

    1999-09-01

    In two Costa Rican rivers used as receptors for domestic sewage, treated by primary stabilization ponds, were taken a total of 28 samplings located at the pond exit and at three different sites in each river: 100 m before the ponds discharge, at the discharge and 100 m after the discharge. These sampling were done for a five and a half years including dry and rainy seasons. In each sampling site, samples were collected of five different substrates: stones, submerge and semi submerge vegetation, tree trunks or sticks, water and artificial substrates. For each sample were used two types of artificial cultures, WC and BG110. A total of 55 cyanobacteria species isolations were obtained, belonging to a 26 genera, between these the most common were Phormidium with nine species, Microcystis with five species, Leptolyngbya and Pseudanabaena with four species each and Oscillatoria with three species. More cyanobacteria species were isolated in water substrate and less isolations in tree trunks and submerge vegetation. Konvophoron, Cyanarcus and Pilgeria only were isolate from water samples inoculated in culture media WC and in few opportunities, while three Leptolyngbya species and four Phormidium species were isolated very often. At the stabilization ponds Phormidium sp4 was dominant in 25 of 28 sampling while in the last others were the chlorophycea I. In this study were observed an increase in the frequency of cyanobacteria at the higher contamination places, and a species substitution between different sampling points. There were no biomass studies, therefore is not possible to relate between different cyanobacteria species and some specific types of water quality.

  8. Pathological effects of cyanobacteria on sea fans in southeast Florida.

    PubMed

    Kiryu, Y; Landsberg, J H; Peters, E C; Tichenor, E; Burleson, C; Perry, N

    2015-07-01

    In early August 2008, observations by divers indicated that sea fans, particularly Gorgonia ventalina, Gorgonia flabellum, and Iciligorgia schrammi, were being covered by benthic filamentous cyanobacteria. From August 2008 through January 2009 and again in April 2009, tissue samples from a targeted G. ventalina colony affected by cyanobacteria and from a nearby, apparently healthy (without cyanobacteria) control colony, were collected monthly for histopathological examination. The primary cellular response of the sea fan to overgrowth by cyanobacteria was an increase in the number of acidophilic amoebocytes (with their granular contents dispersed) that were scattered throughout the coenenchyme tissue. Necrosis of scleroblasts and zooxanthellae and infiltration of degranulated amoebocytes were observed in the sea fan surface tissues at sites overgrown with cyanobacteria. Fungal hyphae in the axial skeleton were qualitatively more prominent in cyanobacteria-affected sea fans than in controls. PMID:25958261

  9. Adventures with Cyanobacteria: A Personal Perspective

    PubMed Central

    Govindjee; Shevela, Dmitriy

    2011-01-01

    Cyanobacteria, or the blue-green algae as they used to be called until 1974, are the oldest oxygenic photosynthesizers. We summarize here adventures with them since the early 1960s. This includes studies on light absorption by cyanobacteria, excitation energy transfer at room temperature down to liquid helium temperature, fluorescence (kinetics as well as spectra) and its relationship to photosynthesis, and afterglow (or thermoluminescence) from them. Further, we summarize experiments on their two-light reaction – two-pigment system, as well as the unique role of bicarbonate (hydrogen carbonate) on the electron-acceptor side of their photosystem II, PSII. This review, in addition, includes a discussion on the regulation of changes in phycobilins (mostly in PSII) and chlorophyll a (Chl a; mostly in photosystem I, PSI) under oscillating light, on the relationship of the slow fluorescence increase (the so-called S to M rise, especially in the presence of diuron) in minute time scale with the so-called state-changes, and on the possibility of limited oxygen evolution in mixotrophic PSI (minus) mutants, up to 30 min, in the presence of glucose. We end this review with a brief discussion on the position of cyanobacteria in the evolution of photosynthetic systems. PMID:22645530

  10. Unscrambling Cyanobacteria Community Dynamics Related to Environmental Factors.

    PubMed

    Bertos-Fortis, Mireia; Farnelid, Hanna M; Lindh, Markus V; Casini, Michele; Andersson, Agneta; Pinhassi, Jarone; Legrand, Catherine

    2016-01-01

    Future climate scenarios in the Baltic Sea project an increase of cyanobacterial bloom frequency and duration, attributed to eutrophication and climate change. Some cyanobacteria can be toxic and their impact on ecosystem services is relevant for a sustainable sea. Yet, there is limited understanding of the mechanisms regulating cyanobacterial diversity and biogeography. Here we unravel successional patterns and changes in cyanobacterial community structure using a 2-year monthly time- series during the productive season in a 100 km coastal-offshore transect using microscopy and high-throughput sequencing of 16S rRNA gene fragments. A total of 565 cyanobacterial OTUs were found, of which 231 where filamentous/colonial and 334 picocyanobacterial. Spatial differences in community structure between coastal and offshore waters were minor. An "epidemic population structure" (dominance of asingle cluster) was found for Aphanizomenon/Dolichospermum within the filamentous/colonial cyanobacterial community. In summer, this clusters imultaneously occurred with opportunistic clusters/OTUs, e.g., Nodularia spumigena and Pseudanabaena. Picocyanobacteria, Synechococcus/Cyanobium, formeda consistent but highly diverse group. Overall, the potential drivers structuring summer cyanobacterial communities were temperature and salinity. However, the different responses to environmental factors among and within genera suggest high niche specificity for individual OTUs. The recruitment and occurrence of potentially toxic filamentous/colonial clusters was likely related to disturbance such as mixing events and short-term shifts in salinity, and not solely dependent on increasing temperature and nitrogen-limiting conditions. Nutrients did not explain further the changes in cyanobacterial community composition. Novel occurrence patterns were identified as a strong seasonal succession revealing a tight coupling between the emergence of opportunistic picocynobacteria and the bloom

  11. Unscrambling Cyanobacteria Community Dynamics Related to Environmental Factors

    PubMed Central

    Bertos-Fortis, Mireia; Farnelid, Hanna M.; Lindh, Markus V.; Casini, Michele; Andersson, Agneta; Pinhassi, Jarone; Legrand, Catherine

    2016-01-01

    Future climate scenarios in the Baltic Sea project an increase of cyanobacterial bloom frequency and duration, attributed to eutrophication and climate change. Some cyanobacteria can be toxic and their impact on ecosystem services is relevant for a sustainable sea. Yet, there is limited understanding of the mechanisms regulating cyanobacterial diversity and biogeography. Here we unravel successional patterns and changes in cyanobacterial community structure using a 2-year monthly time- series during the productive season in a 100 km coastal-offshore transect using microscopy and high-throughput sequencing of 16S rRNA gene fragments. A total of 565 cyanobacterial OTUs were found, of which 231 where filamentous/colonial and 334 picocyanobacterial. Spatial differences in community structure between coastal and offshore waters were minor. An “epidemic population structure” (dominance of asingle cluster) was found for Aphanizomenon/Dolichospermum within the filamentous/colonial cyanobacterial community. In summer, this clusters imultaneously occurred with opportunistic clusters/OTUs, e.g., Nodularia spumigena and Pseudanabaena. Picocyanobacteria, Synechococcus/Cyanobium, formeda consistent but highly diverse group. Overall, the potential drivers structuring summer cyanobacterial communities were temperature and salinity. However, the different responses to environmental factors among and within genera suggest high niche specificity for individual OTUs. The recruitment and occurrence of potentially toxic filamentous/colonial clusters was likely related to disturbance such as mixing events and short-term shifts in salinity, and not solely dependent on increasing temperature and nitrogen-limiting conditions. Nutrients did not explain further the changes in cyanobacterial community composition. Novel occurrence patterns were identified as a strong seasonal succession revealing a tight coupling between the emergence of opportunistic picocynobacteria and the bloom

  12. A new photobioreactor concept enabling the production of desiccation induced biotechnological products using terrestrial cyanobacteria.

    PubMed

    Kuhne, S; Strieth, D; Lakatos, M; Muffler, K; Ulber, R

    2014-12-20

    Cyanobacteria offer great potential for the production of biotechnological products for pharmaceutical applications. However, these organisms can only be cultivated efficiently using photobioreactors (PBR). Under submerged conditions though, terrestrial cyanobacteria mostly grow in a suboptimal way, which makes this cultivation-technique uneconomic and thus terrestrial cyanobacteria unattractive. Therefore, a novel emersed photobioreactor (ePBR) has been developed, which can provide the natural conditions for these organisms. Proof of concept as well as first efficiency tests are conducted using the terrestrial cyanobacteria Trichocoleus sociatus as a model organism. The initial maximum growth rate of T. sociatus (0.014±0.001h(-1)) in submerged systems could be increased by 35%. Furthermore, it is now possible to control desiccation-correlated product formation and related metabolic processes. This is shown for the production of extracellular polymeric substances (EPS). In this case the yield of 0.068±0.006g of EPS/g DW could be increased by more than seven times.

  13. Advances in Metabolic Engineering of Cyanobacteria for Photosynthetic Biochemical Production

    PubMed Central

    Lai, Martin C.; Lan, Ethan I.

    2015-01-01

    Engineering cyanobacteria into photosynthetic microbial cell factories for the production of biochemicals and biofuels is a promising approach toward sustainability. Cyanobacteria naturally grow on light and carbon dioxide, bypassing the need of fermentable plant biomass and arable land. By tapping into the central metabolism and rerouting carbon flux towards desirable compound production, cyanobacteria are engineered to directly convert CO2 into various chemicals. This review discusses the diversity of bioproducts synthesized by engineered cyanobacteria, the metabolic pathways used, and the current engineering strategies used for increasing their titers. PMID:26516923

  14. Modes of Fatty Acid Desaturation in Cyanobacteria: An Update

    PubMed Central

    Los, Dmitry A.; Mironov, Kirill S.

    2015-01-01

    Fatty acid composition of individual species of cyanobacteria is conserved and it may be used as a phylogenetic marker. The previously proposed classification system was based solely on biochemical data. Today, new genomic data are available, which support a need to update a previously postulated FA-based classification of cyanobacteria. These changes are necessary in order to adjust and synchronize biochemical, physiological and genomic data, which may help to establish an adequate comprehensive taxonomic system for cyanobacteria in the future. Here, we propose an update to the classification system of cyanobacteria based on their fatty acid composition. PMID:25809965

  15. Advances in Metabolic Engineering of Cyanobacteria for Photosynthetic Biochemical Production.

    PubMed

    Lai, Martin C; Lan, Ethan I

    2015-01-01

    Engineering cyanobacteria into photosynthetic microbial cell factories for the production of biochemicals and biofuels is a promising approach toward sustainability. Cyanobacteria naturally grow on light and carbon dioxide, bypassing the need of fermentable plant biomass and arable land. By tapping into the central metabolism and rerouting carbon flux towards desirable compound production, cyanobacteria are engineered to directly convert CO₂ into various chemicals. This review discusses the diversity of bioproducts synthesized by engineered cyanobacteria, the metabolic pathways used, and the current engineering strategies used for increasing their titers. PMID:26516923

  16. Determination and occurrence of retinoids in a eutrophic lake (Taihu Lake, China): cyanobacteria blooms produce teratogenic retinal.

    PubMed

    Wu, Xiaoqin; Jiang, Jieqiong; Hu, Jianying

    2013-01-15

    Besides retinoic acids (RAs), some retinoids such as retinal (RAL) and retinol (ROH), which are considered as RA precursors in vertebrates, are also reported to be teratogenic agents. In this study we investigated four RA precursors including RAL, ROH, retinyl palmitate, and β-carotene in the eutrophic Taihu Lake, China, by developing a sensitive analytical method. RAL and β-carotene were widely detected in natural cyanobacteria blooms and lake water. Intracellular concentrations of RAL and β-carotene in blooms were 9.4 to 6.9 × 10(3) and 3.4 to 1.8 × 10(5) ng L(-1), respectively, and their concentrations in lake water were up to 1.4 × 10 ng L(-1) (RAL) and 9.8 × 10(2) ng L(-1) (β-carotene). The good correlation between intracellular concentrations of RAL and RAs implied that RAL was involved in the production of RAs by cyanobacteria blooms. Further examination of 39 cyanobacteria and algae species revealed that most species could produce RAL and β-carotene. The greatest amount of RAL was found in Chlamydomonas sp. (FACHB-715; 1.9 × 10(3) ng g(-1) dry weight). As the main cyanobacteria in Taihu Lake, many Microcystis species could produce high amounts of RAL and were thought to greatly contribute to the production of RAL measured in the blooms. Productions of RAL and β-carotene by cyanobacteria were associated with species, origin location, and growth stage. The results in this study present the existence of a potential risk to aquatic animals living in a eutrophic environment from a high concentration of RAL in cyanobacteria blooms and also provide a clue for further investigating the mechanism underlying the biosynthetic pathway of RAs in cyanobacteria and algae. PMID:23256639

  17. Determination and occurrence of retinoids in a eutrophic lake (Taihu Lake, China): cyanobacteria blooms produce teratogenic retinal.

    PubMed

    Wu, Xiaoqin; Jiang, Jieqiong; Hu, Jianying

    2013-01-15

    Besides retinoic acids (RAs), some retinoids such as retinal (RAL) and retinol (ROH), which are considered as RA precursors in vertebrates, are also reported to be teratogenic agents. In this study we investigated four RA precursors including RAL, ROH, retinyl palmitate, and β-carotene in the eutrophic Taihu Lake, China, by developing a sensitive analytical method. RAL and β-carotene were widely detected in natural cyanobacteria blooms and lake water. Intracellular concentrations of RAL and β-carotene in blooms were 9.4 to 6.9 × 10(3) and 3.4 to 1.8 × 10(5) ng L(-1), respectively, and their concentrations in lake water were up to 1.4 × 10 ng L(-1) (RAL) and 9.8 × 10(2) ng L(-1) (β-carotene). The good correlation between intracellular concentrations of RAL and RAs implied that RAL was involved in the production of RAs by cyanobacteria blooms. Further examination of 39 cyanobacteria and algae species revealed that most species could produce RAL and β-carotene. The greatest amount of RAL was found in Chlamydomonas sp. (FACHB-715; 1.9 × 10(3) ng g(-1) dry weight). As the main cyanobacteria in Taihu Lake, many Microcystis species could produce high amounts of RAL and were thought to greatly contribute to the production of RAL measured in the blooms. Productions of RAL and β-carotene by cyanobacteria were associated with species, origin location, and growth stage. The results in this study present the existence of a potential risk to aquatic animals living in a eutrophic environment from a high concentration of RAL in cyanobacteria blooms and also provide a clue for further investigating the mechanism underlying the biosynthetic pathway of RAs in cyanobacteria and algae.

  18. Engineering cyanobacteria to generate high-value products

    SciTech Connect

    Ducat, DC; Way, JC; Silver, PA

    2011-02-01

    Although many microorganisms have been used for the bioindustrial generation of valuable metabolites, the productive potential of cyanobacterial species has remained largely unexplored. Cyanobacteria possess several advantages as organisms for bioindustrial processes, including simple input requirements, tolerance of marginal agricultural environments, rapid genetics, and carbon-neutral applications that could be leveraged to address global climate change concerns. Here, we review recent research involving the engineering of cyanobacterial species for the production of valuable bioindustrial compounds, including natural cyanobacterial products (e.g. sugars and isoprene), biofuels (e.g. alcohols, alkanes and hydrogen), and other commodity chemicals. Biological and economic obstacles to scaled cyanobacterial production are highlighted, and methods for increasing cyanobacterial production efficiencies are discussed.

  19. The state of autotrophic ethanol production in Cyanobacteria.

    PubMed

    Dexter, J; Armshaw, P; Sheahan, C; Pembroke, J T

    2015-07-01

    Ethanol production directly from CO2 , utilizing genetically engineered photosynthetic cyanobacteria as a biocatalyst, offers significant potential as a renewable and sustainable source of biofuel. Despite the current absence of a commercially successful production system, significant resources have been deployed to realize this goal. Utilizing the pyruvate decarboxylase from Zymomonas species, metabolically derived pyruvate can be converted to ethanol. This review of both peer-reviewed and patent literature focuses on the genetic modifications utilized for metabolic engineering and the resultant effect on ethanol yield. Gene dosage, induced expression and cassette optimizat-ion have been analyzed to optimize production, with production rates of 0·1-0·5 g L(-1) day(-1) being achieved. The current 'toolbox' of molecular manipulations and future directions focusing on applicability, addressing the primary challenges facing commercialization of cyanobacterial technologies are discussed.

  20. Interspecific Differences between D. pulex and D. magna in Tolerance to Cyanobacteria with Protease Inhibitors

    PubMed Central

    Kuster, Christian J.; Von Elert, Eric

    2013-01-01

    It is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. In the present study we investigated potential interspecific differences between two major herbivores, Daphnia magna and Daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. Seven clones each of D. magna and of D. pulex were isolated from different habitats in Europe and North America. To test for interspecific differences in the daphnids’ tolerance to cyanobacteria, their somatic and population growth rates were determined for each D. magna and D. pulex clone after exposure to varying concentrations of two Microcystis aeruginosa strains. The M. aeruginosa strains NIVA and PCC− contained either chymotrypsin or trypsin inhibitors, but no microcystins. Mean somatic and population growth rates on a diet with 20% NIVA were significantly more reduced in D. pulex than in D. magna. On a diet with 10% PCC−, the population growth of D. pulex was significantly more reduced than that of D. magna. This indicates that D. magna is more tolerant to cyanobacteria with protease inhibitors than D. pulex. The reduction of growth rates was possibly caused by an interference of cyanobacterial inhibitors with proteases in the gut of Daphnia, as many other conceivable factors, which might have been able to explain the reduced growth, could be excluded as causal factors. Protease assays revealed that the sensitivities of chymotrypsins and trypsins to cyanobacterial protease inhibitors did not differ between D. magna and D. pulex. However, D. magna exhibited a 2.3-fold higher specific chymotrypsin activity than D. pulex, which explains the observed higher tolerance to cyanobacterial protease inhibitors of D. magna. The present study suggests that D. magna may control the development of cyanobacterial blooms more efficiently than D. pulex due to differences in their tolerance to cyanobacteria with protease inhibitors. PMID:23650523

  1. Identification and characterization of UDP-glucose pyrophosphorylase in cyanobacteria Anabaena sp. PCC 7120.

    PubMed

    Kawano, Yusuke; Sekine, Midori; Ihara, Masaki

    2014-05-01

    Exopolysaccharides produced by photosynthetic cyanobacteria have received considerable attention in recent years for their potential applications in the production of renewable biofuels. Particularly, cyanobacterial cellulose is one of the most promising products because it is extracellularly secreted as a non-crystalline form, which can be easily harvested from the media and converted into glucose units. In cyanobacteria, the production of UDP-glucose, the cellulose precursor, is a key step in the cellulose synthesis pathway. UDP-glucose is synthesized from UTP and glucose-1-phosphate (Glc-1P) by UDP-glucose pyrophosphorylase (UGPase), but this pathway in cyanobacteria has not been well characterized. Therefore, to elucidate the overall cellulose biosynthesis pathway in cyanobacteria, we studied the putative UGPase All3274 and seven other putative NDP-sugar pyrophosphorylases (NSPases), All4645, Alr2825, Alr4491, Alr0188, Alr3400, Alr2361, and Alr3921 of Anabaena sp. PCC 7120. Assays using the purified recombinant proteins revealed that All3274 exhibited UGPase activity, All4645, Alr2825, Alr4491, Alr0188, and Alr3921 exhibited pyrophosphorylase activities on ADP-glucose, CDP-glucose, dTDP-glucose, GDP-mannose, and UDP-N-acetylglucosamine, respectively. Further characterization of All3274 revealed that the kcat for UDP-glucose formation was one or two orders lower than those of other known UGPases. The activity and dimerization tendency of All3274 increased at higher enzyme concentrations, implying catalytic activation by dimerization. However, most interestingly, All3274 dimerization was inhibited by UTP and Glc-1P, but not by UDP-glucose. This study presents the first in vitro characterization of a cyanobacterial UGPase, and provides insights into biotechnological attempts to utilize the photosynthetic production of cellulose from cyanobacteria.

  2. CyanoSpace: cyanobacteria form extreme deserts to space

    NASA Astrophysics Data System (ADS)

    Billi, D.; McKay, C. P.

    2011-10-01

    Extreme-tolerant cyanobacteria belonging to the genus Chroococcidiopsis are suitable model organisms for space experiments. New isolates of Chroococcidiopsis were obtained from survivors scored after exposure to simulated space and Martian conditions. These new isolates offer the challenge to investigate the interconnection between desiccation and radiation resistance; at the same time they might represent improved, stress-selected cyanobacteria for space biotechnology.

  3. Genes, Genomes, and Assemblages of Modern Anoxygenic Photosynthetic Cyanobacteria as Proxies for Ancient Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Grim, S. L.; Dick, G.

    2015-12-01

    Oxygenic photosynthetic (OP) cyanobacteria were responsible for the production of O2 during the Proterozoic. However, the extent and degree of oxygenation of the atmosphere and oceans varied for over 2 Ga after OP cyanobacteria first appeared in the geologic record. Cyanobacteria capable of anoxygenic photosynthesis (AP) may have altered the trajectory of oxygenation, yet the scope of their role in the Proterozoic is not well known. Modern cyanobacterial populations from Middle Island Sinkhole (MIS), Michigan and a handful of cultured cyanobacterial strains, are capable of OP and AP. With their metabolic versatility, these microbes may approximate ancient cyanobacterial assemblages that mediated Earth's oxygenation. To better characterize the taxonomic and genetic signatures of these modern AP/OP cyanobacteria, we sequenced 16S rRNA genes and conducted 'omics analyses on cultured strains, lab mesocosms, and MIS cyanobacterial mat samples collected over multiple years from May to September. Diversity in the MIS cyanobacterial mat is low, with one member of Oscillatoriales dominating at all times. However, Planktothrix members are more abundant in the cyanobacterial community in late summer and fall. The shift in cyanobacterial community composition may be linked to seasonally changing light intensity. In lab mesocosms of MIS microbial mat, we observed a shift in dominant cyanobacterial groups as well as the emergence of Chlorobium, bacteria that specialize in AP. These shifts in microbial community composition and metabolism are likely in response to changing environmental parameters such as the availability of light and sulfide. Further research is needed to understand the impacts of the changing photosynthetic community on oxygen production and the entire microbial consortium. Our study connects genes and genomes of AP cyanobacteria to their environment, and improves understanding of cyanobacterial metabolic strategies that may have shaped Earth's redox evolution.

  4. Natural Product Biosynthetic Diversity and Comparative Genomics of the Cyanobacteria.

    PubMed

    Dittmann, Elke; Gugger, Muriel; Sivonen, Kaarina; Fewer, David P

    2015-10-01

    Cyanobacteria are an ancient lineage of slow-growing photosynthetic bacteria and a prolific source of natural products with intricate chemical structures and potent biological activities. The bulk of these natural products are known from just a handful of genera. Recent efforts have elucidated the mechanisms underpinning the biosynthesis of a diverse array of natural products from cyanobacteria. Many of the biosynthetic mechanisms are unique to cyanobacteria or rarely described from other organisms. Advances in genome sequence technology have precipitated a deluge of genome sequences for cyanobacteria. This makes it possible to link known natural products to biosynthetic gene clusters but also accelerates the discovery of new natural products through genome mining. These studies demonstrate that cyanobacteria encode a huge variety of cryptic gene clusters for the production of natural products, and the known chemical diversity is likely to be just a fraction of the true biosynthetic capabilities of this fascinating and ancient group of organisms.

  5. Nonlinear optical transmission of cyanobacteria-derived optical materials

    NASA Astrophysics Data System (ADS)

    Zhao, Edward H.; Watanabe, Fumiya; Zhao, Wei

    2015-08-01

    Cyanobacteria-derived optical materials for optical limiting applications have been studied in this work. Six samples have been prepared from cyanobacteria including cyanobacteria suspension in water, extracts in water, methanol, and N,N-dimethylformamide, and pyrolyzed cyanobacteria (PCYB) dispersed in dsDNA (sodium salt from salmon testes) solution and sodium dodecyl sulfate solution, respectively. The extracts contain phycocyanin, chlorophyll a, and carotenoids as measured by optical absorption spectroscopy, while the PCYB is a nanostructural composite composed of multi-walled carbon nanotubes, carbon nanoringes, and multilayer graphenes, as revealed by transmission electron microscopy. The optical limiting responses of the samples have been measured at 532 and 756 nm. The PCYB in dsDNA solution has the best limiting performance out of all the cyanobacteria-derived samples. It outperforms carbon black suspension standard at 532 nm and is a broadband limiter, which makes it attractive for optical limiting applications.

  6. NREL Creates New Pathways for Producing Biofuels and Acids from Cyanobacteria (Fact Sheet)

    SciTech Connect

    Not Available

    2012-10-01

    Cyanobacteria use photosynthesis to convert carbon dioxide into glycogen, a carbohydrate that is stored in the cells as an energy source. However, researchers at the National Renewable Energy Laboratory (NREL) have discovered that this photosynthesis can be redirected to produce lipids and valuable organic acids. The research could yield a new source of biofuels, because the lipids can potentially be extracted from the bacteria and converted into biodiesel.

  7. Heterogeneity of Alkane Chain Length in Freshwater and Marine Cyanobacteria

    PubMed Central

    Shakeel, Tabinda; Fatma, Zia; Fatma, Tasneem; Yazdani, Syed Shams

    2015-01-01

    The potential utilization of cyanobacteria for the biological production of alkanes represents an exceptional system for the next generation of biofuels. Here, we analyzed a diverse group of freshwater and marine cyanobacterial isolates from Indian culture collections for their ability to produce both alkanes and alkenes. Among the 50 cyanobacterial isolates screened, 32 isolates; 14 freshwater and 18 marine isolates; produced predominantly alkanes. The GC-MS/MS profiles revealed a higher percentage of pentadecane and heptadecane production for marine and freshwater strains, respectively. Oscillatoria species were found to be the highest producers of alkanes. Among the freshwater isolates, Oscillatoria CCC305 produced the maximum alkane level with 0.43 μg/mg dry cell weight, while Oscillatoria formosa BDU30603 was the highest producer among the marine isolates with 0.13 μg/mg dry cell weight. Culturing these strains under different media compositions showed that the alkane chain length was not influenced by the growth medium but was rather an inherent property of the strains. Analysis of the cellular fatty acid content indicated the presence of predominantly C16 chain length fatty acids in marine strains, while the proportion of C18 chain length fatty acids increased in the majority of freshwater strains. These results correlated with alkane chain length specificity of marine and freshwater isolates indicating that alkane chain lengths may be primarily determined by the fatty acid synthesis pathway. Moreover, the phylogenetic analysis showed clustering of pentadecane-producing marine strains that was distinct from heptadecane-producing freshwater strains strongly suggesting a close association between alkane chain length and the cyanobacteria habitat. PMID:25853127

  8. Raman Characterization of the UV-Protective Pigment Gloeocapsin and Its Role in the Survival of Cyanobacteria.

    PubMed

    Storme, Jean-Yves; Golubic, Stjepko; Wilmotte, Annick; Kleinteich, Julia; Velázquez, David; Javaux, Emmanuelle J

    2015-10-01

    Extracellular UV-screening pigments gloeocapsin and scytonemin present in the exopolysaccharide (EPS) envelopes of extremophilic cyanobacteria of freshwater and marine environments were studied by Raman spectroscopy and compared to their intracellular photosynthetic pigments. This Raman spectral analysis of the extracellular pigment gloeocapsin showed that it shared Raman spectral signatures with parietin, a radiation-protective pigment known in lichens. The UV-light spectra also show similarities. Gloeocapsin occurs in some cyanobacterial species, mostly with exclusion of scytonemin, indicating that these pigments have evolved in cyanobacteria as separate protective strategies. Both gloeocapsin and scytonemin are widely and species-specifically distributed in different cyanobacterial genera and families. The widespread occurrence of these pigments may suggest an early origin, while their detection by Raman spectroscopy makes them potential biosignatures for cyanobacteria in the fossil record and demonstrates the usefulness of nondestructive Raman spectroscopy analyses for the search for complex organics, including possible photosynthetic pigments, if preservable in early Earth and extraterrestrial samples.

  9. Visualizing Virus Assembly Intermediates Inside Marine Cyanobacteria

    PubMed Central

    Dai, Wei; Fu, Caroline; Raytcheva, Desislava; Flanagan, John; Khant, Htet A.; Liu, Xiangan; Rochat, Ryan H.; Haase-Pettingell, Cameron; Piret, Jacqueline; Ludtke, Steve J.; Nagayama, Kuniaki; Schmid, Michael F.; King, Jonathan A.; Chiu, Wah

    2013-01-01

    Summary Cyanobacteria are photosynthetic organisms responsible for ~25% of organic carbon fixation on earth. These bacteria began to convert solar energy and carbon dioxide into bioenergy and oxygen billions of years ago. Cyanophages, which infect these bacteria, play an important role in regulating the marine ecosystem by controlling cyanobacteria community organization and mediating lateral gene transfer. Here we visualize the maturation process of cyanophage Syn5 inside its host cell, Synechococcus, using Zernike Phase Contrast (ZPC) electron cryo-tomography (cryoET)1,2. This imaging modality yields significant enhancement of image contrast over conventional cryoET and thus facilitates the direct identification of subcellular components, including thylakoid membranes, carboxysomes and polyribosomes, as well as phages, inside the congested cytosol of the infected cell. By correlating the structural features and relative abundance of viral progeny within cells at different stages of infection, we identified distinct Syn5 assembly intermediates. Our results suggest that the procapsid releases scaffolding proteins and expands its volume at an early stage of genome packaging. Later in assembly, we detected full particles with a tail either with or without an additional horn. The morphogenetic pathway we describe herein is highly conserved and was probably established long before that of double stranded DNA (dsDNA) viruses infecting higher life forms. PMID:24107993

  10. Hydrotaxis of cyanobacteria in desert crusts.

    PubMed

    Pringault, O; Garcia-Pichel, F

    2004-05-01

    We studied the migration of cyanobacteria in desert crusts from Las Bárdenas Reales (Spain). The crusts were almost exclusively colonized by the filamentous cyanobacterium Oscillatoria, which formed a dense layer approximately 600 microm thick located between 1.5 and 2.1 mm deep. Laboratory and field experiments showed that saturation of the crust with liquid water induced a migration of the cyanobacteria leading to a significant greening of the surface within a few minutes. Under light and rapid evaporation, the green color rapidly disappeared and the crust surface was completely devoid of filaments within 60 min. In contrast, 260 min was required to recover the original white color of the crust when slow evaporation was experimentally imposed. The up and down migration following wetting and drying occurred also in the dark. This demonstrates that light was not a required stimulus. Addition of ATP synthesis inhibitors prevented the cyanobacterium from migrating down into the crust, with filaments remaining on the surface. Therefore, the disappearance of the green color observed during desiccation can only be attributed to an active cyanobacterial motility response to the decrease in the water content. The simplest explanation that can account for the evidence gathered is the presence of a mechanism that links, directly or indirectly, these motility responses to gradients in water content, namely a form of hydrotaxis. PMID:14605777

  11. Response of cyanobacteria to low atmosphere pressure

    NASA Astrophysics Data System (ADS)

    Qin, Lifeng; Ai, Weidang; Guo, Shuangsheng; Tang, Yongkang; Yu, Qingni; Shen, Yunze; Ren, Jin

    Maintaining a low pressure environment would reduce the technological complexity and constructed cost of future lunar base. To estimate the effect of hypobaric of controlled ecological life support system in lunar base on terrestrial life, cyanobacteria was used as the model to exam the response of growth, morphology, physiology to it. The decrease of atmosphere pressure from 100 KPa to 50 KPa reducing the growth rates of Microcystis aeruginosa, Merismopedia.sp, Anabaena sp. PCC 7120, Anabaena Hos-aquae, the chlorophyll a content in Microcystis aeruginosa, Merismopedia.sp, Anabaena Hos-aquae, the carotenoid content in Microcystis aeruginosa, Merismopedia.sp and Anabaena sp. PCC 7120, the phycocyanin content in Microcystis aeruginosa. This study explored the biological characteristics of the cyanobacteria under low pressure condition, which aimed at understanding the response of the earth's life to environment for the future moon base, the results enrich the research contents of the lunar biology and may be referred for the research of other terrestrial life, such as human, plant, microbe and animal living in life support system of lunar base.

  12. Hydrogenases and Hydrogen Metabolism of Cyanobacteria

    PubMed Central

    Tamagnini, Paula; Axelsson, Rikard; Lindberg, Pia; Oxelfelt, Fredrik; Wünschiers, Röbbe; Lindblad, Peter

    2002-01-01

    Cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupSL) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxFUYH) which has the capacity to both take up and produce hydrogen. This review summarizes our knowledge about cyanobacterial hydrogenases, focusing on recent progress since the first molecular information was published in 1995. It presents the molecular knowledge about cyanobacterial hupSL and hoxFUYH, their corresponding gene products, and their accessory genes before finishing with an applied aspect—the use of cyanobacteria in a biological, renewable production of the future energy carrier molecular hydrogen. In addition to scientific publications, information from three cyanobacterial genomes, the unicellular Synechocystis strain PCC 6803 and the filamentous heterocystous Anabaena strain PCC 7120 and Nostoc punctiforme (PCC 73102/ATCC 29133) is included. PMID:11875125

  13. Acetylcholinesterase in Biofouling Species: Characterization and Mode of Action of Cyanobacteria-Derived Antifouling Agents.

    PubMed

    Almeida, Joana R; Freitas, Micaela; Cruz, Susana; Leão, Pedro N; Vasconcelos, Vitor; Cunha, Isabel

    2015-07-24

    Effective and ecofriendly antifouling (AF) compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE) activity as an effect and/or mode of action of promising AF compounds, since AChE inhibitors were found to inhibit invertebrate larval settlement. To pursue this objective, in vitro quantification of AChE activity under the effect of several cyanobacterial strain extracts as potential AF agents was performed along with in vivo AF (anti-settlement) screening tests. Pre-characterization of different cholinesterases (ChEs) forms present in selected tissues of important biofouling species was performed to confirm the predominance of AChE, and an in vitro AF test using pure AChE activity was developed. Eighteen cyanobacteria strains were tested as source of potential AF and AChE inhibitor agents. Results showed effectiveness in selecting promising eco-friendly AF agents, allowing the understanding of the AF biochemical mode of action induced by different compounds. This study also highlights the potential of cyanobacteria as source of AF agents towards invertebrate macrofouling species.

  14. Acetylcholinesterase in Biofouling Species: Characterization and Mode of Action of Cyanobacteria-Derived Antifouling Agents.

    PubMed

    Almeida, Joana R; Freitas, Micaela; Cruz, Susana; Leão, Pedro N; Vasconcelos, Vitor; Cunha, Isabel

    2015-08-01

    Effective and ecofriendly antifouling (AF) compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE) activity as an effect and/or mode of action of promising AF compounds, since AChE inhibitors were found to inhibit invertebrate larval settlement. To pursue this objective, in vitro quantification of AChE activity under the effect of several cyanobacterial strain extracts as potential AF agents was performed along with in vivo AF (anti-settlement) screening tests. Pre-characterization of different cholinesterases (ChEs) forms present in selected tissues of important biofouling species was performed to confirm the predominance of AChE, and an in vitro AF test using pure AChE activity was developed. Eighteen cyanobacteria strains were tested as source of potential AF and AChE inhibitor agents. Results showed effectiveness in selecting promising eco-friendly AF agents, allowing the understanding of the AF biochemical mode of action induced by different compounds. This study also highlights the potential of cyanobacteria as source of AF agents towards invertebrate macrofouling species. PMID:26213967

  15. Acetylcholinesterase in Biofouling Species: Characterization and Mode of Action of Cyanobacteria-Derived Antifouling Agents

    PubMed Central

    Almeida, Joana R.; Freitas, Micaela; Cruz, Susana; Leão, Pedro N.; Vasconcelos, Vitor; Cunha, Isabel

    2015-01-01

    Effective and ecofriendly antifouling (AF) compounds have been arising from naturally produced chemicals. The objective of this study is to use cyanobacteria-derived agents to investigate the role of acetylcholinesterase (AChE) activity as an effect and/or mode of action of promising AF compounds, since AChE inhibitors were found to inhibit invertebrate larval settlement. To pursue this objective, in vitro quantification of AChE activity under the effect of several cyanobacterial strain extracts as potential AF agents was performed along with in vivo AF (anti-settlement) screening tests. Pre-characterization of different cholinesterases (ChEs) forms present in selected tissues of important biofouling species was performed to confirm the predominance of AChE, and an in vitro AF test using pure AChE activity was developed. Eighteen cyanobacteria strains were tested as source of potential AF and AChE inhibitor agents. Results showed effectiveness in selecting promising eco-friendly AF agents, allowing the understanding of the AF biochemical mode of action induced by different compounds. This study also highlights the potential of cyanobacteria as source of AF agents towards invertebrate macrofouling species. PMID:26213967

  16. Quantitative PCR Enumeration of Total/Toxic Planktothrix rubescens and Total Cyanobacteria in Preserved DNA Isolated from Lake Sediments▿†

    PubMed Central

    Savichtcheva, Olga; Debroas, Didier; Kurmayer, Rainer; Villar, Clement; Jenny, Jean Philippe; Arnaud, Fabien; Perga, Marie Elodie; Domaizon, Isabelle

    2011-01-01

    The variability of spatial distribution and the determinism of cyanobacterial blooms, as well as their impact at the lake scale, are still not understood, partly due to the lack of long-term climatic and environmental monitoring data. The paucity of these data can be alleviated by the use of proxy data from high-resolution sampling of sediments. Coupling paleolimnological and molecular tools and using biomarkers such as preserved DNA are promising approaches, although they have not been performed often enough so far. In our study, a quantitative PCR (qPCR) technique was applied to enumerate total cyanobacterial and total and toxic Planktothrix communities in preserved DNA derived from sediments of three lakes located in the French Alps (Lake Geneva, Lake Bourget, and Lake Annecy), containing a wide range of cyanobacterial species. Preserved DNA from lake sediments was analyzed to assess its quality, quantity, and integrity, with further application for qPCR. We applied the qPCR assay to enumerate the total cyanobacterial community, and multiplex qPCR assays were applied to quantify total and microcystin-producing Planktothrix populations in a single reaction tube. These methods were optimized, calibrated, and applied to sediment samples, and the specificity and reproducibility of qPCR enumeration were tested. Accurate estimation of potential inhibition within sediment samples was performed to assess the sensitivity of such enumeration by qPCR. Some precautions needed for interpreting qPCR results in the context of paleolimnological approaches are discussed. We concluded that the qPCR assay can be used successfully for the analysis of lake sediments when DNA is well preserved in order to assess the presence and dominance of cyanobacterial and Planktothrix communities. PMID:21984244

  17. Estimating cyanobacteria community dynamics and its relationship with environmental factors.

    PubMed

    Luo, Wenhuai; Chen, Huirong; Lei, Anping; Lu, Jun; Hu, Zhangli

    2014-01-20

    The cyanobacteria community dynamics in two eutrophic freshwater bodies (Tiegang Reservoir and Shiyan Reservoir) was studied with both a traditional microscopic counting method and a PCR-DGGE genotyping method. Results showed that cyanobacterium Phormidium tenue was the predominant species; twenty-six cyanobacteria species were identified in water samples collected from the two reservoirs, among which fourteen were identified with the morphological method and sixteen with the PCR-DGGE method. The cyanobacteria community composition analysis showed a seasonal fluctuation from July to December. The cyanobacteria population peaked in August in both reservoirs, with cell abundances of 3.78 × 10(8) cells L(-1) and 1.92 × 10(8) cells L(-1) in the Tiegang and Shiyan reservoirs, respectively. Canonical Correspondence Analysis (CCA) was applied to further investigate the correlation between cyanobacteria community dynamics and environmental factors. The result indicated that the cyanobacteria community dynamics was mostly correlated with pH, temperature and total nitrogen. This study demonstrated that data obtained from PCR-DGGE combined with a traditional morphological method could reflect cyanobacteria community dynamics and its correlation with environmental factors in eutrophic freshwater bodies.

  18. Estimating Cyanobacteria Community Dynamics and its Relationship with Environmental Factors

    PubMed Central

    Luo, Wenhuai; Chen, Huirong; Lei, Anping; Lu, Jun; Hu, Zhangli

    2014-01-01

    The cyanobacteria community dynamics in two eutrophic freshwater bodies (Tiegang Reservoir and Shiyan Reservoir) was studied with both a traditional microscopic counting method and a PCR-DGGE genotyping method. Results showed that cyanobacterium Phormidium tenue was the predominant species; twenty-six cyanobacteria species were identified in water samples collected from the two reservoirs, among which fourteen were identified with the morphological method and sixteen with the PCR-DGGE method. The cyanobacteria community composition analysis showed a seasonal fluctuation from July to December. The cyanobacteria population peaked in August in both reservoirs, with cell abundances of 3.78 × 108 cells L-1 and 1.92 × 108 cells L-1 in the Tiegang and Shiyan reservoirs, respectively. Canonical Correspondence Analysis (CCA) was applied to further investigate the correlation between cyanobacteria community dynamics and environmental factors. The result indicated that the cyanobacteria community dynamics was mostly correlated with pH, temperature and total nitrogen. This study demonstrated that data obtained from PCR-DGGE combined with a traditional morphological method could reflect cyanobacteria community dynamics and its correlation with environmental factors in eutrophic freshwater bodies. PMID:24448632

  19. Nezha, a novel active miniature inverted-repeat transposable element in cyanobacteria

    SciTech Connect

    Zhou Fengfeng; Tran Thao; Xu Ying

    2008-01-25

    Miniature inverted-repeat transposable elements (MITEs) were first identified in plants and exerted extensive proliferations throughout eukaryotic and archaeal genomes. But very few MITEs have been characterized in bacteria. We identified a novel MITE, called Nezha, in cyanobacteria Anabaena variabilis ATCC 29413 and Nostoc sp. PCC 7120. Nezha, like most previously known MITEs in other organisms, is small in size, non-coding, carrying TIR and DR signals, and of potential to form a stable RNA secondary structure, and it tends to insert into A+T-rich regions. Recent transpositions of Nezha were observed in A. variabilis ATCC 29413 and Nostoc sp. PCC 7120, respectively. Nezha might have proliferated recently with aid from the transposase encoded by ISNpu3-like elements. A possible horizontal transfer event of Nezha from cyanobacteria to Polaromonas JS666 is also observed.

  20. Cyanobacteria cultivation in industrial wastewaters and biodiesel production from their biomass: a review.

    PubMed

    Balasubramanian, Lavanya; Subramanian, Geetha; Nazeer, Thayiba Thanveer; Simpson, Hannah Shalini; Rahuman, Shifina T; Raju, Preetha

    2011-01-01

    As an alternative fuel biodiesel has become increasingly important due to diminishing petroleum reserves and adverse environmental consequences of exhaust gases from petroleum-fueled engines. Recently, research interest has focused on the production of biofuel from microalgae. Cyanobacteria appeared to be suitable candidates for cultivation in wastes and wastewaters because they produce biomass in satisfactory quantity and can be harvested relatively easily due to their size and structure. In addition, their biomass composition can be manipulated by several environmental and operational factors to produce biomass with concrete characteristics. Herein, we review the culture of cyanobacteria in wastewaters and also the potential resources that can be transformed into biodiesel successfully for meeting the ever-increasing demand for biodiesel production. PMID:21838795

  1. Cyanobacteria and Cyanotoxins: From Impacts on Aquatic Ecosystems and Human Health to Anticarcinogenic Effects

    PubMed Central

    Zanchett, Giliane; Oliveira-Filho, Eduardo C.

    2013-01-01

    Cyanobacteria or blue-green algae are among the pioneer organisms of planet Earth. They developed an efficient photosynthetic capacity and played a significant role in the evolution of the early atmosphere. Essential for the development and evolution of species, they proliferate easily in aquatic environments, primarily due to human activities. Eutrophic environments are conducive to the appearance of cyanobacterial blooms that not only affect water quality, but also produce highly toxic metabolites. Poisoning and serious chronic effects in humans, such as cancer, have been described. On the other hand, many cyanobacterial genera have been studied for their toxins with anticancer potential in human cell lines, generating promising results for future research toward controlling human adenocarcinomas. This review presents the knowledge that has evolved on the topic of toxins produced by cyanobacteria, ranging from their negative impacts to their benefits. PMID:24152991

  2. Cyanobacteria and cyanotoxins: from impacts on aquatic ecosystems and human health to anticarcinogenic effects.

    PubMed

    Zanchett, Giliane; Oliveira-Filho, Eduardo C

    2013-10-01

    Cyanobacteria or blue-green algae are among the pioneer organisms of planet Earth. They developed an efficient photosynthetic capacity and played a significant role in the evolution of the early atmosphere. Essential for the development and evolution of species, they proliferate easily in aquatic environments, primarily due to human activities. Eutrophic environments are conducive to the appearance of cyanobacterial blooms that not only affect water quality, but also produce highly toxic metabolites. Poisoning and serious chronic effects in humans, such as cancer, have been described. On the other hand, many cyanobacterial genera have been studied for their toxins with anticancer potential in human cell lines, generating promising results for future research toward controlling human adenocarcinomas. This review presents the knowledge that has evolved on the topic of toxins produced by cyanobacteria, ranging from their negative impacts to their benefits.

  3. Collective evolution of cyanobacteria and cyanophages mediated by horizontal gene transfer

    NASA Astrophysics Data System (ADS)

    Shih, Hong-Yan; Rogers, Tim; Goldenfeld, Nigel

    We describe a model for how antagonistic predator-prey coevolution can lead to mutualistic adaptation to an environment, as a result of horizontal gene transfer. Our model is a simple description of ecosystems such as marine cyanobacteria and their predator cyanophages, which carry photosynthesis genes. These genes evolve more rapidly in the virosphere than the bacterial pan-genome, and thus the bacterial population could potentially benefit from phage predation. By modeling both the barrier to predation and horizontal gene transfer, we study this balance between individual sacrifice and collective benefits. The outcome is an emergent mutualistic coevolution of improved photosynthesis capability, benefiting both bacteria and phage. This form of multi-level selection can contribute to niche stratification in the cyanobacteria-phage ecosystem. This work is supported in part by a cooperative agreement with NASA, Grant NNA13AA91A/A0018.

  4. Cyanobacteria and cyanotoxins: from impacts on aquatic ecosystems and human health to anticarcinogenic effects.

    PubMed

    Zanchett, Giliane; Oliveira-Filho, Eduardo C

    2013-10-01

    Cyanobacteria or blue-green algae are among the pioneer organisms of planet Earth. They developed an efficient photosynthetic capacity and played a significant role in the evolution of the early atmosphere. Essential for the development and evolution of species, they proliferate easily in aquatic environments, primarily due to human activities. Eutrophic environments are conducive to the appearance of cyanobacterial blooms that not only affect water quality, but also produce highly toxic metabolites. Poisoning and serious chronic effects in humans, such as cancer, have been described. On the other hand, many cyanobacterial genera have been studied for their toxins with anticancer potential in human cell lines, generating promising results for future research toward controlling human adenocarcinomas. This review presents the knowledge that has evolved on the topic of toxins produced by cyanobacteria, ranging from their negative impacts to their benefits. PMID:24152991

  5. Comparative Metagenomics of Toxic Freshwater Cyanobacteria Bloom Communities on Two Continents

    SciTech Connect

    Steffen, Morgan M; Li, Zhou; Effler, Chad; Hauser, Loren John; Boyer, Gergory; Wilhelm, Steven W

    2012-01-01

    Toxic cyanobacterial blooms have persisted in freshwater systems around the world for centuries and appear to be globally increasing in frequency and severity. Toxins produced by bloom-associated cyanobacteria can have drastic impacts on the ecosystem and surrounding communities, and bloom biomass can disrupt aquatic food webs and act as a driver for hypoxia. Little is currently known regarding the genomic content of the Microcystis strains that form blooms or the companion heterotrophic community associated with bloom events. To address these issues, we examined the bloomassociated microbial communities in single samples from Lake Erie (North America), Lake Tai (Taihu, China), and Grand Lakes St. Marys (OH, USA) using comparative metagenomics. Together the Cyanobacteria and Proteobacteria comprised .90% of each bloom bacterial community sample, although the dominant phylum varied between systems. Relative to the existing Microcystis aeruginosa NIES 843 genome, sequences from Lake Erie and Taihu revealed a number of metagenomic islands that were absent in the environmental samples. Moreover, despite variation in the phylogenetic assignments of bloomassociated organisms, the functional potential of bloom members remained relatively constant between systems. This pattern was particularly noticeable in the genomic contribution of nitrogen assimilation genes. In Taihu, the genetic elements associated with the assimilation and metabolism of nitrogen were predominantly associated with Proteobacteria, while these functions in the North American lakes were primarily contributed to by the Cyanobacteria. Our observations build on an emerging body of metagenomic surveys describing the functional potential of microbial communities as more highly conserved than that of their phylogenetic makeup within natural systems.

  6. Dataset exploited for the development and validation of automated cyanobacteria quantification algorithm, ACQUA.

    PubMed

    Gandola, Emanuele; Antonioli, Manuela; Traficante, Alessio; Franceschini, Simone; Scardi, Michele; Congestri, Roberta

    2016-09-01

    The estimation and quantification of potentially toxic cyanobacteria in lakes and reservoirs are often used as a proxy of risk for water intended for human consumption and recreational activities. Here, we present data sets collected from three volcanic Italian lakes (Albano, Vico, Nemi) that present filamentous cyanobacteria strains at different environments. Presented data sets were used to estimate abundance and morphometric characteristics of potentially toxic cyanobacteria comparing manual Vs. automated estimation performed by ACQUA ("ACQUA: Automated Cyanobacterial Quantification Algorithm for toxic filamentous genera using spline curves, pattern recognition and machine learning" (Gandola et al., 2016) [1]). This strategy was used to assess the algorithm performance and to set up the denoising algorithm. Abundance and total length estimations were used for software development, to this aim we evaluated the efficiency of statistical tools and mathematical algorithms, here described. The image convolution with the Sobel filter has been chosen to denoise input images from background signals, then spline curves and least square method were used to parameterize detected filaments and to recombine crossing and interrupted sections aimed at performing precise abundances estimations and morphometric measurements. PMID:27500194

  7. Energy status and immune system alterations in Elliptio complanata after ingestion of cyanobacteria Anabaena flos-aquae.

    PubMed

    Gélinas, Malorie; Fortier, Marlène; Lajeunesse, André; Fournier, Michel; Gagnon, Christian; Gagné, François

    2013-04-01

    Cyanobacteria have often been described as nutritionally poor for herbivorous organisms. To gain additional information on the potential impacts of invertebrates feeding on cyanobacteria, we fed Elliptio complanata mussels with two types of algae: Anabaena flos-aquae (cyanobacteria) and Pseudokirchneriella subcapitata (green algae). Physiological parameters were examined at the energy status, immune system and oxidative stress levels. Energy status was examined by following the rate of electron transport activity in mitochondria (a measure of cellular energy expense) and lipid/sugar stores in the visceral mass. The cyanobacteria were not actively producing toxins. Based on the digestive gland index, the mussels fed equally on either regime. However, the energy status in mussels fed A. flos-aquae revealed that the total sugar was lower in the digestive gland, whereas mitochondrial electron transport activity (MET), once corrected against the digestive gland somatic index, showed increased energy expenses. Acetylcholinesterase activity and lipid peroxidation (LPO) were also higher in mussels fed with A. flos-aquae compared with mussels fed with P. subcapitata. LPO was correlated by mitochondrial activity in both the digestive gland and gills, suggesting that oxidative stress resulted from metabolic respiration. Immunocompetence (phagocytic activity, natural killer cell-like activity, haemocyte count and viability) and humoral level of lysozyme were not affected in mussels by the algae or cyanobacteria regime. Moreover, the xenobiotic conjugating enzyme, glutathione S-transferase, hemoprotein oxidase and vitellogenin-like proteins were not affected in mussel organs via ingestion of A. flos-aquae. Our study suggests that ingestion of cyanobacteria leads to increased energy expenses, oxidative stress and increased acetylcholine turnover in mussels. PMID:23354932

  8. Recreational and occupational field exposure to freshwater cyanobacteria – a review of anecdotal and case reports, epidemiological studies and the challenges for epidemiologic assessment

    PubMed Central

    Stewart, Ian; Webb, Penelope M; Schluter, Philip J; Shaw, Glen R

    2006-01-01

    Cyanobacteria are common inhabitants of freshwater lakes and reservoirs throughout the world. Under favourable conditions, certain cyanobacteria can dominate the phytoplankton within a waterbody and form nuisance blooms. Case reports and anecdotal references dating from 1949 describe a range of illnesses associated with recreational exposure to cyanobacteria: hay fever-like symptoms, pruritic skin rashes and gastro-intestinal symptoms are most frequently reported. Some papers give convincing descriptions of allergic reactions while others describe more serious acute illnesses, with symptoms such as severe headache, pneumonia, fever, myalgia, vertigo and blistering in the mouth. A coroner in the United States found that a teenage boy died as a result of accidentally ingesting a neurotoxic cyanotoxin from a golf course pond. This death is the first recorded human fatality attributed to recreational exposure to cyanobacteria, although uncertainties surround the forensic identification of the suspected cyanotoxin in this case. We systematically reviewed the literature on recreational exposure to freshwater cyanobacteria. Epidemiological data are limited, with six studies conducted since 1990. Statistically significant increases in symptoms were reported in individuals exposed to cyanobacteria compared to unexposed counterparts in two Australian cohort studies, though minor morbidity appeared to be the main finding. The four other small studies (three from the UK, one Australian) did not report any significant association. However, the potential for serious injury or death remains, as freshwater cyanobacteria under bloom conditions are capable of producing potent toxins that cause specific and severe dysfunction to hepatic or central nervous systems. The exposure route for these toxins is oral, from ingestion of recreational water, and possibly by inhalation. A range of freshwater microbial agents may cause acute conditions that present with features that resemble

  9. Live-cell imaging of cyanobacteria.

    PubMed

    Yokoo, Rayka; Hood, Rachel D; Savage, David F

    2015-10-01

    Cyanobacteria are a diverse bacterial phylum whose members possess a high degree of ultrastructural organization and unique gene regulatory mechanisms. Unraveling this complexity will require the use of live-cell fluorescence microscopy, but is impeded by the inherent fluorescent background associated with light-harvesting pigments and the need to feed photosynthetic cells light. Here, we outline a roadmap for overcoming these challenges. Specifically, we show that although basic cyanobacterial biology creates challenging experimental constraints, these restrictions can be mitigated by the careful choice of fluorophores and microscope instrumentation. Many of these choices are motivated by recent successful live-cell studies. We therefore also highlight how live-cell imaging has advanced our understanding of bacterial microcompartments, circadian rhythm, and the organization and segregation of the bacterial nucleoid.

  10. Cyanobacteria for Human Habitation beyond Earth

    NASA Technical Reports Server (NTRS)

    Brown, Igor; Jones, Jeff; Bayless, David; Sarkisova, Svetlana; Garrison, Dan; McKay, David S.

    2007-01-01

    In light of the President s Moon/Mars initiative, lunar exploration has once again become a priority for NASA. In order to establish permanent bases on the Moon and proceed with human exploration of Mars, two key problems will be addressed: first, the production of O2 and second, the production of methane (CH4). While O2 is required for life support systems (LSS), both liquid O2 and CH4 are needed as an oxidizer and a propellant, respectively for the Lunar Surface Access Module (LSAM) and the Crew Exploration Vehicle (CEV). Unlike previous propulsion systems, the new CEV will use liquid oxygen (LO2) as an oxidizer and liquid methane (LCH4) as a propellant. Existing technology (e.g. hydrogen reduction) for the production of liquid oxygen from lunar regolith is very energy intensive and requires high temperature reactors. We propose an alternative approach using iron-tolerant cyanobacteria. We have found that iron-tolerant cyanobacteria (IT CB) are capable of etching iron-bearing minerals, which may lead to bonds breaking between Fe and O of common lunar mare basalt Fe-oxides including ilmenite, pseudobrookite, ferropseudobrookite, and armalcolite with the subsequent release of both Fe, Ti and oxygen as byproducts. We also propose to use CB biomass for CH4 production as carbon stock and a propellant. Both processes can be accomplished in an energy and cost effective manner because sunlight will be used as an energy source and allows the reactions at ambient temperatures between 10-60 C. Current evaluations include assessing the thermodynamics of such biogenic reactions using a variety of nutrients and atmospheric parameters, as well as assessing the rates and species variation effects of the driving reactions.

  11. Application of synthetic biology in cyanobacteria and algae

    PubMed Central

    Wang, Bo; Wang, Jiangxin; Zhang, Weiwen; Meldrum, Deirdre R.

    2012-01-01

    Cyanobacteria and algae are becoming increasingly attractive cell factories for producing renewable biofuels and chemicals due to their ability to capture solar energy and CO2 and their relatively simple genetic background for genetic manipulation. Increasing research efforts from the synthetic biology approach have been made in recent years to modify cyanobacteria and algae for various biotechnological applications. In this article, we critically review recent progresses in developing genetic tools for characterizing or manipulating cyanobacteria and algae, the applications of genetically modified strains for synthesizing renewable products such as biofuels and chemicals. In addition, the emergent challenges in the development and application of synthetic biology for cyanobacteria and algae are also discussed. PMID:23049529

  12. Human Health Effects Associated with Exposure to Toxic Cyanobacteria

    EPA Science Inventory

    Reports of toxic cyanobacteria blooms are increasing worldwide. Warming and eutrophic surface water systems support the development of blooms. We examine the evidence for adverse human health effects associated with exposure to toxic blooms in drinking water, recreational water a...

  13. An expanded genomic representation of the phylum cyanobacteria.

    PubMed

    Soo, Rochelle M; Skennerton, Connor T; Sekiguchi, Yuji; Imelfort, Michael; Paech, Samuel J; Dennis, Paul G; Steen, Jason A; Parks, Donovan H; Tyson, Gene W; Hugenholtz, Philip

    2014-05-01

    Molecular surveys of aphotic habitats have indicated the presence of major uncultured lineages phylogenetically classified as members of the Cyanobacteria. One of these lineages has recently been proposed as a nonphotosynthetic sister phylum to the Cyanobacteria, the Melainabacteria, based on recovery of population genomes from human gut and groundwater samples. Here, we expand the phylogenomic representation of the Melainabacteria through sequencing of six diverse population genomes from gut and bioreactor samples supporting the inference that this lineage is nonphotosynthetic, but not the assertion that they are strictly fermentative. We propose that the Melainabacteria is a class within the phylogenetically defined Cyanobacteria based on robust monophyly and shared ancestral traits with photosynthetic representatives. Our findings are consistent with theories that photosynthesis occurred late in the Cyanobacteria and involved extensive lateral gene transfer and extends the recognized functionality of members of this phylum.

  14. Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs.

    PubMed

    Karlson, Agnes M L; Duberg, Jon; Motwani, Nisha H; Hogfors, Hedvig; Klawonn, Isabell; Ploug, Helle; Barthel Svedén, Jennie; Garbaras, Andrius; Sundelin, Brita; Hajdu, Susanna; Larsson, Ulf; Elmgren, Ragnar; Gorokhova, Elena

    2015-06-01

    Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N2 allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.

  15. An Expanded Genomic Representation of the Phylum Cyanobacteria

    PubMed Central

    Soo, Rochelle M.; Skennerton, Connor T.; Sekiguchi, Yuji; Imelfort, Michael; Paech, Samuel J.; Dennis, Paul G.; Steen, Jason A.; Parks, Donovan H.; Tyson, Gene W.; Hugenholtz, Philip

    2014-01-01

    Molecular surveys of aphotic habitats have indicated the presence of major uncultured lineages phylogenetically classified as members of the Cyanobacteria. One of these lineages has recently been proposed as a nonphotosynthetic sister phylum to the Cyanobacteria, the Melainabacteria, based on recovery of population genomes from human gut and groundwater samples. Here, we expand the phylogenomic representation of the Melainabacteria through sequencing of six diverse population genomes from gut and bioreactor samples supporting the inference that this lineage is nonphotosynthetic, but not the assertion that they are strictly fermentative. We propose that the Melainabacteria is a class within the phylogenetically defined Cyanobacteria based on robust monophyly and shared ancestral traits with photosynthetic representatives. Our findings are consistent with theories that photosynthesis occurred late in the Cyanobacteria and involved extensive lateral gene transfer and extends the recognized functionality of members of this phylum. PMID:24709563

  16. 2-Methylhopanoids: Biomarkers for Cyanobacteria and for Oxygenic Photosynthesis

    NASA Technical Reports Server (NTRS)

    Summons, R. E.; Jahnke, L. L.; Hope, J. M.; Logan, G. A.

    1999-01-01

    This paper reports new biomarker and carbon isotopic data for cultured cyanobacteria, cyano-bacterially- dominated ecosystems and ancient sedi-ments and petroleum. We found that cyanobacteria are the predominant source of a distinctive membrane lipid biomarker, namely 2- methylbacteriohopanepolyol (2-Me-BHP). We then sought evidence for a geochemical record of the fossil hydrocarbon analogues of these compounds (2- methylhopanes) and found a trend toward their in-creased relative abundance in marine sediments going back through geological time to 2500 Ma. We conclude that cyanobacteria were the dominant form of phytoplankton and source of molecular oxygen in the Proterozoic ocean. Extending the geological record of cyanobacteria further to Archean times is now a matter of finding a suitably preserved rock record. Additional information is contained in the original extended abstract.

  17. Field and laboratory guide to freshwater cyanobacteria harmful algal blooms for Native American and Alaska Native communities

    USGS Publications Warehouse

    Rosen, Barry H.; Ann St. Amand,

    2015-09-14

    Cyanobacteria can produce toxins and form harmful algal blooms. The Native American and Alaska Native communities that are dependent on subsistence fishing have an increased risk of exposure to these cyanotoxins. It is important to recognize the presence of an algal bloom in a waterbody and to distinguish a potentially toxic harmful algal bloom from a non-toxic bloom. This guide provides field images that show cyanobacteria blooms, some of which can be toxin producers, as well as other non-toxic algae blooms and floating plants that might be confused with algae. After recognition of a potential toxin-producing cyanobacterial bloom in the field, the type(s) of cyanobacteria present needs to be identified. Species identification, which requires microscopic examination, may help distinguish a toxin-producer from a non-toxin producer. This guide also provides microscopic images of the common cyanobacteria that are known to produce toxins, as well as images of algae that form blooms but do not produce toxins.

  18. Field and laboratory guide to freshwater cyanobacteria harmful algal blooms for Native American and Alaska Native communities

    USGS Publications Warehouse

    Rosen, Barry H.; Ann St. Amand

    2015-01-01

    Cyanobacteria can produce toxins and form harmful algal blooms. The Native American and Alaska Native communities that are dependent on subsistence fishing have an increased risk of exposure to these cyanotoxins. It is important to recognize the presence of an algal bloom in a waterbody and to distinguish a potentially toxic harmful algal bloom from a non-toxic bloom. This guide provides field images that show cyanobacteria blooms, some of which can be toxin producers, as well as other non-toxic algae blooms and floating plants that might be confused with algae. After recognition of a potential toxin-producing cyanobacterial bloom in the field, the type(s) of cyanobacteria present needs to be identified. Species identification, which requires microscopic examination, may help distinguish a toxin-producer from a non-toxin producer. This guide also provides microscopic images of the common cyanobacteria that are known to produce toxins, as well as images of algae that form blooms but do not produce toxins.

  19. Harnessing the self-harvesting capability of benthic cyanobacteria for use in benthic photobioreactors

    PubMed Central

    2011-01-01

    Benthic species of algae and cyanobacteria (i.e., those that grow on surfaces), may provide potential advantages over planktonic species for some commercial-scale biotechnological applications. A multitude of different designs of photobioreactor (PBR) are available for growing planktonic species but to date there has been little research on PBR for benthic algae or cyanobacteria. One notable advantage of some benthic cyanobacterial species is that during their growth cycle they become positively buoyant, detach from the growth surface and form floating mats. This 'self-harvesting' capability could be advantageous in commercial PBRs as it would greatly reduce dewatering costs. In this study we compared the growth rates and efficiency of 'self-harvesting' among three species of benthic cyanobacteria; Phormidium autumnale; Phormidium murrayi and Planktothrix sp.. Phormidium autumnale produced the greatest biomass and formed cohesive mats once detached. Using this strain and an optimised MLA media, a variety of geometries of benthic PBRs (bPBRs) were trialed. The geometry and composition of growth surface had a marked effect on cyanobacterial growth. The highest biomass was achieved in a bPBR comprising of a vertical polyethylene bag with loops of silicone tubing to provide additional growth surfaces. The productivity achieved in this bPBR was a similar order of magnitude as planktonic species, with the additional advantage that towards the end of the exponential phase the bulk of the biomass detached forming a dense mat at the surface of the medium. PMID:21906375

  20. Catalog of microscopic organisms of the Everglades, Part 1—The cyanobacteria

    USGS Publications Warehouse

    Rosen, Barry H.; Mareš, Jan

    2016-07-27

    The microscopic organisms of the Everglades include numerous prokaryotic organisms, including the eubacteria, such as the cyanobacteria and non-photosynthetic bacteria, as well as several eukaryotic algae and protozoa that form the base of the food web. This report is part 1 in a series of reports that describe microscopic organisms encountered during the examination of several hundred samples collected in the southern Everglades. Part 1 describes the cyanobacteria and includes a suite of images and the most current taxonomic treatment of each taxon. The majority of the images are of live organisms, allowing their true color to be represented. A number of potential new species are illustrated; however, corroborating evidence from a genetic analysis of the morphological characteristics is needed to confirm these designations as new species. Part 1 also includes images of eubacteria that resemble cyanobacteria. Additional parts of the report on microscopic organisms of the Everglades are currently underway, such as the green algae and diatoms. The report also serves as the basis for a taxonomic image database that will provide a digital record of the Everglades microscopic flora and fauna. It is anticipated that these images will facilitate current and future ecological studies on the Everglades, such as understanding food-web dynamics, sediment formation and accumulation, the effects of nutrients and flow, and climate change.

  1. Catalog of microscopic organisms of the Everglades, Part 1—The cyanobacteria

    USGS Publications Warehouse

    Rosen, Barry H.; Mareš, Jan

    2016-01-01

    The microscopic organisms of the Everglades include numerous prokaryotic organisms, including the eubacteria, such as the cyanobacteria and non-photosynthetic bacteria, as well as several eukaryotic algae and protozoa that form the base of the food web. This report is part 1 in a series of reports that describe microscopic organisms encountered during the examination of several hundred samples collected in the southern Everglades. Part 1 describes the cyanobacteria and includes a suite of images and the most current taxonomic treatment of each taxon. The majority of the images are of live organisms, allowing their true color to be represented. A number of potential new species are illustrated; however, corroborating evidence from a genetic analysis of the morphological characteristics is needed to confirm these designations as new species. Part 1 also includes images of eubacteria that resemble cyanobacteria. Additional parts of the report on microscopic organisms of the Everglades are currently underway, such as the green algae and diatoms. The report also serves as the basis for a taxonomic image database that will provide a digital record of the Everglades microscopic flora and fauna. It is anticipated that these images will facilitate current and future ecological studies on the Everglades, such as understanding food-web dynamics, sediment formation and accumulation, the effects of nutrients and flow, and climate change.

  2. Invasion of Nostocales (cyanobacteria) to Subtropical and Temperate Freshwater Lakes - Physiological, Regional, and Global Driving Forces.

    PubMed

    Sukenik, Assaf; Hadas, Ora; Kaplan, Aaron; Quesada, Antonio

    2012-01-01

    Similar to the increased number of studies on invasive plants and animals in terrestrial and aquatic ecosystems, many reports were recently published on the invasion of Nostocales (cyanobacteria) to freshwater environments worldwide. Invasion and proliferation of Nostocales in new habitats have the potential to significantly alter the structure of the native community and to modify ecosystem functioning. But most importantly, they influence the water quality due to a variety of toxic compounds that some species produce. Therefore a special attention was given to the invasion and persistence of toxic cyanobacteria in many aquatic ecosystems. Here we summarize the currently published records on the invasion of two Nostocales genera, Cylindrospermopsis and Aphanizomenon, to lakes and water reservoirs in subtropical and temperate zones. These invading species possess traits thought to be common to many invasive organisms: high growth rate, high resource utilization efficiency and overall superior competitive abilities over native species when local conditions vary. Assuming that dispersion routes of cyanobacteria have not been changed much in recent decades, their recent establishment and proliferation in new habitats indicate changes in the environment under which they can exploit their physiological advantage over the native phytoplankton population. In many cases, global warming was identified as the major driving force for the invasion of Nostocales. Due to this uncontrollable trend, invasive Nostocales species are expected to maintain their presence in new habitats and further expand to new environments. In other cases, regional changes in nutrient loads and in biotic conditions were attributed to the invasion events.

  3. Is exposure to cyanobacteria an environmental risk factor for amyotrophic lateral sclerosis and other neurodegenerative diseases?

    USGS Publications Warehouse

    Bradley, Walter G.; Borenstein, Amy R.; Nelson, Lorene M.; Codd, Geoffrey A.; Rosen, Barry H.; Stommel, Elijah W.; Cox, Paul Alan

    2013-01-01

    There is a broad scientific consensus that amyotrophic lateral sclerosis (ALS) is caused by gene-environment interactions. Mutations in genes underlying familial ALS (fALS) have been discovered in only 5–10% of the total population of ALS patients. Relatively little attention has been paid to environmental and lifestyle factors that may trigger the cascade of motor neuron death leading to the syndrome of ALS, although exposure to chemicals including lead and pesticides, and to agricultural environments, smoking, certain sports, and trauma have all been identified with an increased risk of ALS. There is a need for research to quantify the relative roles of each of the identified risk factors for ALS. Recent evidence has strengthened the theory that chronic environmental exposure to the neurotoxic amino acid β-N-methylamino-L-alanine (BMAA) produced by cyanobacteria may be an environmental risk factor for ALS. Here we describe methods that may be used to assess exposure to cyanobacteria, and hence potentially to BMAA, namely an epidemiologic questionnaire and direct and indirect methods for estimating the cyanobacterial load in ecosystems. Rigorous epidemiologic studies could determine the risks associated with exposure to cyanobacteria, and if combined with genetic analysis of ALS cases and controls could reveal etiologically important gene-environment interactions in genetically vulnerable individuals.

  4. Cyanobacteria and cyanotoxins are present in drinking water impoundments and groundwater wells in desert environments.

    PubMed

    Chatziefthimiou, Aspassia D; Metcalf, James S; Glover, W Broc; Banack, Sandra A; Dargham, Soha R; Richer, Renee A

    2016-05-01

    Desert environments and drylands experience a drastic scarcity of water resources. To alleviate dependence on freshwater for drinking water needs, countries have invested in infrastructure development of desalination plants. Collectively, the countries of the Arabian Gulf produce 45% of the world's desalinated water, which is stored in dams, mega-reservoirs and secondary house water tanks to secure drinking water beyond daily needs. Improper storage practices of drinking water in impoundments concomitant with increased temperatures and light penetration may promote the growth of cyanobacteria and accumulation of cyanotoxins. To shed light on this previously unexplored research area in desert environments, we examined drinking and irrigation water of urban and rural environments to determine whether cyanobacteria and cyanotoxins are present, and what are the storage and transportation practices as well as the environmental parameters that best predict their presence. Cyanobacteria were present in 80% of the urban and 33% of the rural water impoundments. Neurotoxins BMAA, DAB and anatoxin-a(S) were not detected in any of the water samples, although they have been found to accumulate in the desert soils, which suggests a bioaccumulation potential if they are leached into the aquifer. A toxic BMAA isomer, AEG, was found in 91.7% of rural but none of the urban water samples and correlated with water-truck transportation, light exposure and chloride ions. The hepatotoxic cyanotoxin microcystin-LR was present in the majority of all sampled impoundments, surpassing the WHO provisional guideline of 1 μg/l in 30% of the urban water tanks. Finally, we discuss possible management strategies to improve storage and transportation practices in order to minimize exposure to cyanobacteria and cyanotoxins, and actions to promote sustainable use of limited water resources. PMID:26921462

  5. Cyanobacteria and cyanotoxins are present in drinking water impoundments and groundwater wells in desert environments.

    PubMed

    Chatziefthimiou, Aspassia D; Metcalf, James S; Glover, W Broc; Banack, Sandra A; Dargham, Soha R; Richer, Renee A

    2016-05-01

    Desert environments and drylands experience a drastic scarcity of water resources. To alleviate dependence on freshwater for drinking water needs, countries have invested in infrastructure development of desalination plants. Collectively, the countries of the Arabian Gulf produce 45% of the world's desalinated water, which is stored in dams, mega-reservoirs and secondary house water tanks to secure drinking water beyond daily needs. Improper storage practices of drinking water in impoundments concomitant with increased temperatures and light penetration may promote the growth of cyanobacteria and accumulation of cyanotoxins. To shed light on this previously unexplored research area in desert environments, we examined drinking and irrigation water of urban and rural environments to determine whether cyanobacteria and cyanotoxins are present, and what are the storage and transportation practices as well as the environmental parameters that best predict their presence. Cyanobacteria were present in 80% of the urban and 33% of the rural water impoundments. Neurotoxins BMAA, DAB and anatoxin-a(S) were not detected in any of the water samples, although they have been found to accumulate in the desert soils, which suggests a bioaccumulation potential if they are leached into the aquifer. A toxic BMAA isomer, AEG, was found in 91.7% of rural but none of the urban water samples and correlated with water-truck transportation, light exposure and chloride ions. The hepatotoxic cyanotoxin microcystin-LR was present in the majority of all sampled impoundments, surpassing the WHO provisional guideline of 1 μg/l in 30% of the urban water tanks. Finally, we discuss possible management strategies to improve storage and transportation practices in order to minimize exposure to cyanobacteria and cyanotoxins, and actions to promote sustainable use of limited water resources.

  6. Morphology and Elemental Composition of Recent and Fossil Cyanobacteria

    NASA Technical Reports Server (NTRS)

    SaintAmand, Ann; Hoover, Richard B.; Jerman, Gregory; Rozanov, Alexei Yu.

    2005-01-01

    Cyanobacteria (cyanophyta, cyanoprokaryota, and blue-green algae) are an ancient, diverse and abundant group of photosynthetic oxygenic microorganisms. Together with other bacteria and archaea, the cyanobacteria have been the dominant life forms on Earth for over 3.5 billion years. Cyanobacteria occur in some of our planets most extreme environments - hot springs and geysers, hypersaline and alkaline lakes, hot and cold deserts, and the polar ice caps. They occur in a wide variety of morphologies. Unlike archaea and other bacteria, which are typically classified in pure culture by their physiological, biochemical and phylogenetic properties, the cyanobacteria have historically been classified based upon their size and morphological characteristics. These include the presence or absence of heterocysts, sheath, uniseriate or multiseriate trichomes, true or false branching, arrangement of thylakoids, reproduction by akinetes, binary fission, hormogonia, fragmentation, presence/absence of motility etc. Their antiquity, distribution, structural and chemical differentiation, diversity, morphological complexity and large size compared to most other bacteria, makes the cyanobacteria ideal candidates for morphological biomarkers in returned Astromaterials. We have obtained optical (nomarski and phase contrast)/fluorescent (blue and green excitation) microscopy images using an Olympus BX60 compound microscope and Field Emission Scanning Electron Microscopy images and EDAX elemental compositions of living and fossil cyanobacteria. The S-4000 Hitachi Field Emission Scanning Electron Microscope (FESEM) has been used to investigate microfossils in freshly fractured interior surfaces of terrestrial rocks and the cells, hormogonia, sheaths and trichomes of recent filamentous cyanobacteria. We present Fluorescent and FESEM Secondary and Backscattered Electron images and associated EDAX elemental analyses of recent and fossil cyanobacteria, concentrating on representatives of the

  7. [CO2-Concentrating Mechanism and Its Traits in Haloalkaliphilic Cyanobacteria].

    PubMed

    Kupriyanova, E V; Samylina, O S

    2015-01-01

    Cyanobacteria are a group of oxygenic phototrophs existing for at least 3.5 Ga. Photosynthetic CO2 assimilation by cyanobacteria occurs via the Calvin cycle, with RuBisCO, its key enzyme, having very low affinity to CO2. This is due to the fact that atmospheric CO2 concentration in Archaean, when the photosynthetic apparatus evolved, was several orders higher than now. Later, in the epoch of Precambrian microbial communities, CO2 content in the atmosphere decreased drastically. Thus, present-day phototrophs, including cyanobacteria, require adaptive mechanisms for efficient photosynthesis. In cyanobacterial cells, this function is performed by the CO2-concentrating mechanism (CCM), which creates elevated CO2 concentrations in the vicinity of RuBisCO active centers, thus significantly increasing the rate of CO2 fixation in the Calvin cycle. CCM has been previously studied only for freshwater and marine cyanobacteria. We were the first to investigate CCM in haloalkaliphilic cyanobacteria from soda lakes. Extremophilic haloalkaliphilic cyanobacteria were shown to possess a well-developed CCM with the structure and functional principles similar to those of freshwater and marine strains. Analysis of available data suggests that regulation of the amount of inorganic carbon transported into the cell is probably the general CCM function under these conditions.

  8. Hypoxia sustains cyanobacteria blooms in the Baltic sea.

    PubMed

    Funkey, Carolina P; Conley, Daniel J; Reuss, Nina S; Humborg, Christoph; Jilbert, Tom; Slomp, Caroline P

    2014-01-01

    Nutrient over-enrichment is one of the classic triggering mechanisms for the occurrence of cyanobacteria blooms in aquatic ecosystems. In the Baltic Sea, cyanobacteria regularly occur in the late summer months and form nuisance accumulations in surface waters and their abundance has intensified significantly in the past 50 years attributed to human-induced eutrophication. However, the natural occurrence of cyanobacteria during the Holocene is debated. In this study, we present records of cyanobacteria pigments, water column redox proxies, and nitrogen isotopic signatures for the past ca. 8000 years from Baltic Sea sediment cores. Our results demonstrate that cyanobacteria abundance and nitrogen fixation are correlated with hypoxia occurring during three main intervals: (1) ca. 7000-4000 B.P. during the Littorina transgression, (2) ca. 1400-700 B.P. during the Medieval Climate Anomaly, and (3) from ca. 1950 A.D. to the present. Issues of preservation were investigated, and we show that organic matter and pigment profiles are not simply an artifact of preservation. These results suggest that cyanobacteria abundance is sustained during periods of hypoxia, most likely because of enhanced recycling of phosphorus in low oxygen conditions.

  9. Hypoxia sustains cyanobacteria blooms in the Baltic sea.

    PubMed

    Funkey, Carolina P; Conley, Daniel J; Reuss, Nina S; Humborg, Christoph; Jilbert, Tom; Slomp, Caroline P

    2014-01-01

    Nutrient over-enrichment is one of the classic triggering mechanisms for the occurrence of cyanobacteria blooms in aquatic ecosystems. In the Baltic Sea, cyanobacteria regularly occur in the late summer months and form nuisance accumulations in surface waters and their abundance has intensified significantly in the past 50 years attributed to human-induced eutrophication. However, the natural occurrence of cyanobacteria during the Holocene is debated. In this study, we present records of cyanobacteria pigments, water column redox proxies, and nitrogen isotopic signatures for the past ca. 8000 years from Baltic Sea sediment cores. Our results demonstrate that cyanobacteria abundance and nitrogen fixation are correlated with hypoxia occurring during three main intervals: (1) ca. 7000-4000 B.P. during the Littorina transgression, (2) ca. 1400-700 B.P. during the Medieval Climate Anomaly, and (3) from ca. 1950 A.D. to the present. Issues of preservation were investigated, and we show that organic matter and pigment profiles are not simply an artifact of preservation. These results suggest that cyanobacteria abundance is sustained during periods of hypoxia, most likely because of enhanced recycling of phosphorus in low oxygen conditions. PMID:24512281

  10. Hypoxia Sustains Cyanobacteria Blooms in the Baltic Sea

    PubMed Central

    2014-01-01

    Nutrient over-enrichment is one of the classic triggering mechanisms for the occurrence of cyanobacteria blooms in aquatic ecosystems. In the Baltic Sea, cyanobacteria regularly occur in the late summer months and form nuisance accumulations in surface waters and their abundance has intensified significantly in the past 50 years attributed to human-induced eutrophication. However, the natural occurrence of cyanobacteria during the Holocene is debated. In this study, we present records of cyanobacteria pigments, water column redox proxies, and nitrogen isotopic signatures for the past ca. 8000 years from Baltic Sea sediment cores. Our results demonstrate that cyanobacteria abundance and nitrogen fixation are correlated with hypoxia occurring during three main intervals: (1) ca. 7000–4000 B.P. during the Littorina transgression, (2) ca. 1400–700 B.P. during the Medieval Climate Anomaly, and (3) from ca. 1950 A.D. to the present. Issues of preservation were investigated, and we show that organic matter and pigment profiles are not simply an artifact of preservation. These results suggest that cyanobacteria abundance is sustained during periods of hypoxia, most likely because of enhanced recycling of phosphorus in low oxygen conditions. PMID:24512281

  11. [CO2-Concentrating Mechanism and Its Traits in Haloalkaliphilic Cyanobacteria].

    PubMed

    Kupriyanova, E V; Samylina, O S

    2015-01-01

    Cyanobacteria are a group of oxygenic phototrophs existing for at least 3.5 Ga. Photosynthetic CO2 assimilation by cyanobacteria occurs via the Calvin cycle, with RuBisCO, its key enzyme, having very low affinity to CO2. This is due to the fact that atmospheric CO2 concentration in Archaean, when the photosynthetic apparatus evolved, was several orders higher than now. Later, in the epoch of Precambrian microbial communities, CO2 content in the atmosphere decreased drastically. Thus, present-day phototrophs, including cyanobacteria, require adaptive mechanisms for efficient photosynthesis. In cyanobacterial cells, this function is performed by the CO2-concentrating mechanism (CCM), which creates elevated CO2 concentrations in the vicinity of RuBisCO active centers, thus significantly increasing the rate of CO2 fixation in the Calvin cycle. CCM has been previously studied only for freshwater and marine cyanobacteria. We were the first to investigate CCM in haloalkaliphilic cyanobacteria from soda lakes. Extremophilic haloalkaliphilic cyanobacteria were shown to possess a well-developed CCM with the structure and functional principles similar to those of freshwater and marine strains. Analysis of available data suggests that regulation of the amount of inorganic carbon transported into the cell is probably the general CCM function under these conditions. PMID:26263620

  12. Use of cyanobacteria for in-situ resource use in space applications

    NASA Astrophysics Data System (ADS)

    Olsson-Francis, Karen; Cockell, Charles S.

    2010-08-01

    The regolith of other planetary bodies, such as the Moon and Mars, is rich in inorganic elements that could potentially be exploited for space applications. Lithotrophic microorganisms that are capable of utilising rocks as a growth substrate, and facilitate the extraction of elements, are ideal candidates for in-situ resource use. Of particular interest are the cyanobacteria, which have been suggested for applications, such as oxygen, fuel and biomass production, nutrient acquisition, and feedstock provisions. In this study, Gloeocapsa strain OU_20, isolated from a rock-dwelling community exposed to low Earth orbit; Leptolyngbya strain OU_13 and Phormidium strain OU_10, both isolated from a rock-dwelling community exposed to Mars simulated conditions; Chroococcidiopsis 029; Arthrospira platensis; Synechococcus elongatus; and Anabaena cylindrica, were examined as potential organisms for space in-situ resource use. Volcanic rocks, including basalt (low in SiO 2) analogous to martian and lunar basalt, rhyolite (high in SiO 2), and anorthosite analogous to lunar regolith were used as growth substrates. The growth rate and rock dissolution were significantly lower with rhyolite demonstrating the importance of silica content in defining the potential for in-situ resource use. Biological weathering resulted in the release of bio-essential elements from the rock matrix, highlighting the potential of cyanobacteria for applications such as bio-mining and nutrient acquisition, on other planets. A. cylindrica produced the maximum biomass with the three rock-types and the optimal value was obtained with the basalt. Exposure experiments demonstrated that A. cylindrica, Chroococcidiopsis 029, Gloeocapsa strain OU_20, Phormidium strain OU_10, and Leptolyngbya strain OU_13 were able to survive 28 days of exposure to desiccation and Mars simulated conditions, which is beneficial in case of system malfunction and for storage. The results from this study indicate that cyanobacteria

  13. Diversity and Physiology of Siderophilic Cyanobacteria: Implication for the Bioenergetics

    NASA Technical Reports Server (NTRS)

    Brown, Igor; Sarkisova, Svetlana; Thomas-Kerprta, Kathie; McKay, David S.

    2008-01-01

    Prior to 2.4 Ga, global oceans were likely significantly enriched in soluble iron (Rouxel, Bekker, Edwards, 2005), a condition that is not conducive to the growth of most contemporary mesophilic cyanobacteria (CB). Recent studies of the mechanisms of iron-deficiency stress in CB suggest that contemporary mesophilic freshwater and marine B underwent long-term adaptation to a permanent decrease in soluble iron in the ocean environment (Boyer, et al., 1987; Braun, Hantke, and Koster, 1998). Of all extant environments, iron-depositing hot springs may constitute the most appropriate natural models for analysis of the transition of ancestral cyanobacteria (CB) or protocyanobacteria (PCB) (Olson, 2001) from anoxygenic photosynthesis to oxygenic one and biogeochemical processes in the late Archean and early Paleoproterozoic eras. In particular, Olson (2001) proposed the definition for PCB and postulated that the common ancestor of PCB and CB might well have used Fe(OH)+ as the principal electron donor for CO2 fixation (Widdel, et al., 1993; Ehrenreich and Widdel, 1994; Pierson and Olson, 1989; Olson, 2006). Olson (2001) proposed that the driving force for the evolution of RC2, in addition to RC1, was the necessity to use Fe(OH)+ effectively for CO2 fixation in the absence of reduced sulfur compounds. The global decrease of dissolved environmental reduced iron could have been the driving force for the transition from anoxygenic to oxygenic photosynthesis (Brown et al., 2007). Despite the insights into the ecology, evolutionary biology, paleogeobiochemistry, and astrobiology the examination of iron depositing hot springs (IDHS) could potentially provide, very few studies dedicated to the diversity and physiology of cyanobacteria inhabiting IDHS have been conducted. Here we describe the phylogeny, physiology and ultrastructure and biogeochemical activity of several recent CB isolates from two different greater Yellowstone area IDHS, e.g. LaDuke and Chocolate Pots

  14. Towards clarifying what distinguishes cyanobacteria able to resurrect after desiccation from those that cannot: The photosynthetic aspect.

    PubMed

    Raanan, Hagai; Oren, Nadav; Treves, Haim; Keren, Nir; Ohad, Itzhak; Berkowicz, Simon M; Hagemann, Martin; Koch, Moriz; Shotland, Yoram; Kaplan, Aaron

    2016-06-01

    Organisms inhabiting biological soil crusts (BSCs) are able to cope with extreme environmental conditions including daily hydration/dehydration cycles, high irradiance and extreme temperatures. The photosynthetic machinery, potentially the main source of damaging reactive oxygen species during cessation of CO(2) fixation in desiccating cells, must be protected to avoid sustained photodamage. We compared certain photosynthetic parameters and the response to excess light of BCS-inhabiting, desiccation-tolerant cyanobacteria Leptolyngbya ohadii and Nostoc reinholdii with those observed in the "model" organisms Nostoc sp. PCC 7120, able to resurrect after mild desiccation, and Synechococcus elongatus PCC 7942 and Synechocystis sp. PCC 6803 that are unable to recover from dehydration. Desiccation-tolerant strains exhibited a transient decline in the photosynthetic rate at light intensities corresponding to the inflection point in the PI curve relating the O(2) evolution rate to light intensity. They also exhibited a faster and larger loss of variable fluorescence and profoundly faster Q(A)(-) re-oxidation rates after exposure to high illumination. Finally, a smaller difference was found in the temperature of maximal thermoluminescence signal in the absence or presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) than observed in "model" cyanobacteria. These parameters indicate specific functional differences of photosystem II (PSII) between desiccation tolerant and sensitive cyanobacteria. We propose that exposure to excess irradiation activates a non-radiative electron recombination route inside PSII that minimizes formation of damaging singlet oxygen in the desiccation-tolerant cyanobacteria and thereby reduces photodamage. PMID:26896589

  15. The effects of three chemical algaecides on cell numbers and toxin content of the cyanobacteria Microcystis aeruginosa and Anabaenopsis sp.

    PubMed

    Greenfield, Dianne I; Duquette, Ashley; Goodson, Abby; Keppler, Charles J; Williams, Sarah H; Brock, Larissa M; Stackley, Krista D; White, David; Wilde, Susan B

    2014-11-01

    Toxic cyanobacteria blooms are a growing concern for public health and safety, due in part to the production of the hepatotoxin microcystin by certain species, including Microcystis aeruginosa. Management strategies for controlling cyanobacteria blooms include algaecide treatments, often with copper sulfate, and more recently oxidizers such as sodium percarbonate that produce hydrogen peroxide. This study assessed the effects of two copper-containing algaecides and one sodium percarbonate-containing algaecide on mitigating cell numbers and toxin content of cultured M. aeruginosa and summer (July) bloom samples of Anabaenopsis sp. in a brackish stormwater detention pond. Monitoring of the bloom revealed that Anabaenopsis sp. was associated with elevated levels of orthophosphate compared to nitrogen (dissolved inorganic nitrogen to phosphorus ratios were 0.19-1.80), and the bloom decline (September-October) was likely due to lower autumn water temperatures combined with potential grazing by the dinoflagellate Protoperidinium quinquecorne. Laboratory-based algaecide experiments included three dose levels, and cyanobacteria cell numbers and microcystin concentrations (particulate and dissolved) were evaluated over 7 d. Following exposure, copper-containing treatments generally had lower cell numbers than either sodium percarbonate-containing or control (no algaecide) treatments. Addition of algaecides did not reduce overall microcystin levels, and a release of toxin from the particulate to dissolved phase was observed in most treatments. These findings indicate that algaecide applications may visibly control cyanobacteria bloom densities, but not necessarily toxin concentrations, and have implications for public health and safety.

  16. Identification of geosmin and 2-methylisoborneol in cyanobacteria and molecular detection methods for the producers of these compounds.

    PubMed

    Suurnäkki, Suvi; Gomez-Saez, Gonzalo V; Rantala-Ylinen, Anne; Jokela, Jouni; Fewer, David P; Sivonen, Kaarina

    2015-01-01

    Geosmin and 2-methylisoborneol (MIB) are muddy/earthy off-flavor metabolites produced by a range of bacteria. Cyanobacteria are the major producers of the volatile metabolites geosmin and MIB which produce taste and odor problems in drinking water and fish worldwide. Here we detected geosmin and MIB by studying 100 cyanobacteria strains using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS). A total of 21 geosmin producers were identified from six cyanobacteria genera. Two of the geosmin producers also produced MIB. A PCR protocol for the detection of geoA and MIB synthase genes involved in the biosynthesis of geosmin and MIB was developed. The geoA and MIB synthase genes were detected in all strains shown to produce geosmin and MIB, respectively. Cyanobacterial geoA and MIB synthase sequences showed homology to terpene synthases genes of actinobacteria and proteobacteria. Additional off-flavor compounds, nor-carotenoids β-ionone and β-cyclocitral, were found from 55 strains among the 100 cyanobacterial strains studied; β-ionone was present in 45 and β-cyclocitral in 10 strains. Six of the cyanobacteria which contain off-flavor compounds also produced toxins, anatoxin-a or microcystins. The molecular method developed is a useful tool in monitoring potential cyanobacterial producers of geosmin and MIB.

  17. Towards clarifying what distinguishes cyanobacteria able to resurrect after desiccation from those that cannot: The photosynthetic aspect.

    PubMed

    Raanan, Hagai; Oren, Nadav; Treves, Haim; Keren, Nir; Ohad, Itzhak; Berkowicz, Simon M; Hagemann, Martin; Koch, Moriz; Shotland, Yoram; Kaplan, Aaron

    2016-06-01

    Organisms inhabiting biological soil crusts (BSCs) are able to cope with extreme environmental conditions including daily hydration/dehydration cycles, high irradiance and extreme temperatures. The photosynthetic machinery, potentially the main source of damaging reactive oxygen species during cessation of CO(2) fixation in desiccating cells, must be protected to avoid sustained photodamage. We compared certain photosynthetic parameters and the response to excess light of BCS-inhabiting, desiccation-tolerant cyanobacteria Leptolyngbya ohadii and Nostoc reinholdii with those observed in the "model" organisms Nostoc sp. PCC 7120, able to resurrect after mild desiccation, and Synechococcus elongatus PCC 7942 and Synechocystis sp. PCC 6803 that are unable to recover from dehydration. Desiccation-tolerant strains exhibited a transient decline in the photosynthetic rate at light intensities corresponding to the inflection point in the PI curve relating the O(2) evolution rate to light intensity. They also exhibited a faster and larger loss of variable fluorescence and profoundly faster Q(A)(-) re-oxidation rates after exposure to high illumination. Finally, a smaller difference was found in the temperature of maximal thermoluminescence signal in the absence or presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) than observed in "model" cyanobacteria. These parameters indicate specific functional differences of photosystem II (PSII) between desiccation tolerant and sensitive cyanobacteria. We propose that exposure to excess irradiation activates a non-radiative electron recombination route inside PSII that minimizes formation of damaging singlet oxygen in the desiccation-tolerant cyanobacteria and thereby reduces photodamage.

  18. The effects of three chemical algaecides on cell numbers and toxin content of the cyanobacteria Microcystis aeruginosa and Anabaenopsis sp.

    PubMed

    Greenfield, Dianne I; Duquette, Ashley; Goodson, Abby; Keppler, Charles J; Williams, Sarah H; Brock, Larissa M; Stackley, Krista D; White, David; Wilde, Susan B

    2014-11-01

    Toxic cyanobacteria blooms are a growing concern for public health and safety, due in part to the production of the hepatotoxin microcystin by certain species, including Microcystis aeruginosa. Management strategies for controlling cyanobacteria blooms include algaecide treatments, often with copper sulfate, and more recently oxidizers such as sodium percarbonate that produce hydrogen peroxide. This study assessed the effects of two copper-containing algaecides and one sodium percarbonate-containing algaecide on mitigating cell numbers and toxin content of cultured M. aeruginosa and summer (July) bloom samples of Anabaenopsis sp. in a brackish stormwater detention pond. Monitoring of the bloom revealed that Anabaenopsis sp. was associated with elevated levels of orthophosphate compared to nitrogen (dissolved inorganic nitrogen to phosphorus ratios were 0.19-1.80), and the bloom decline (September-October) was likely due to lower autumn water temperatures combined with potential grazing by the dinoflagellate Protoperidinium quinquecorne. Laboratory-based algaecide experiments included three dose levels, and cyanobacteria cell numbers and microcystin concentrations (particulate and dissolved) were evaluated over 7 d. Following exposure, copper-containing treatments generally had lower cell numbers than either sodium percarbonate-containing or control (no algaecide) treatments. Addition of algaecides did not reduce overall microcystin levels, and a release of toxin from the particulate to dissolved phase was observed in most treatments. These findings indicate that algaecide applications may visibly control cyanobacteria bloom densities, but not necessarily toxin concentrations, and have implications for public health and safety. PMID:25078538

  19. The Effects of Three Chemical Algaecides on Cell Numbers and Toxin Content of the Cyanobacteria Microcystis aeruginosa and Anabaenopsis sp.

    NASA Astrophysics Data System (ADS)

    Greenfield, Dianne I.; Duquette, Ashley; Goodson, Abby; Keppler, Charles J.; Williams, Sarah H.; Brock, Larissa M.; Stackley, Krista D.; White, David; Wilde, Susan B.

    2014-11-01

    Toxic cyanobacteria blooms are a growing concern for public health and safety, due in part to the production of the hepatotoxin microcystin by certain species, including Microcystis aeruginosa. Management strategies for controlling cyanobacteria blooms include algaecide treatments, often with copper sulfate, and more recently oxidizers such as sodium percarbonate that produce hydrogen peroxide. This study assessed the effects of two copper-containing algaecides and one sodium percarbonate-containing algaecide on mitigating cell numbers and toxin content of cultured M. aeruginosa and summer (July) bloom samples of Anabaenopsis sp. in a brackish stormwater detention pond. Monitoring of the bloom revealed that Anabaenopsis sp. was associated with elevated levels of orthophosphate compared to nitrogen (dissolved inorganic nitrogen to phosphorus ratios were 0.19-1.80), and the bloom decline (September-October) was likely due to lower autumn water temperatures combined with potential grazing by the dinoflagellate Protoperidinium quinquecorne. Laboratory-based algaecide experiments included three dose levels, and cyanobacteria cell numbers and microcystin concentrations (particulate and dissolved) were evaluated over 7 d. Following exposure, copper-containing treatments generally had lower cell numbers than either sodium percarbonate-containing or control (no algaecide) treatments. Addition of algaecides did not reduce overall microcystin levels, and a release of toxin from the particulate to dissolved phase was observed in most treatments. These findings indicate that algaecide applications may visibly control cyanobacteria bloom densities, but not necessarily toxin concentrations, and have implications for public health and safety.

  20. Spatiotemporal distribution pattern of cyanobacteria community and its relationship with the environmental factors in Hongze Lake, China.

    PubMed

    Ren, Ying; Pei, Haiyan; Hu, Wenrong; Tian, Chang; Hao, Daping; Wei, Jielin; Feng, Yawei

    2014-10-01

    Hongze Lake, located in the east route of the South-to-North Water Diversion Project (SNWDP), is a potential drinking water source for the residents along this water diversion project. Based on a monthly sampling at 11 stations in three regions of Hongze Lake, the spatiotemporal distribution pattern of cyanobacteria community was comprehensively investigated from March 2011 to February 2013. A total of 23 cyanobacterial species which belong to 16 genera were identified, and Microcystis was the most predominant cyanobacterial genus mainly composed of Microcystis wesenbergii in Hongze Lake. The cyanobacterial abundance ranged from 0 to 2.6 × 10(7) cells/L, and the average cyanobacteria abundance of Northern region was significantly higher than those of Western region and Eastern region in the 2-year study. The total cyanobacteria abundance and the Microcystis abundance both took on a similar seasonal regularity in the three regions. The results of correlation analysis indicated that Microcystis abundance was correlated with water temperature, chemical oxygen demand (COD)Mn, nitrate (NO₃-N), and total nitrogen (TN)/total phosphorus (TP) mass ratio, among which water temperature had the highest correlation coefficient. In summer, cyanobacteria blooms may take place under suitable environmental conditions at some special areas in Hongze Lake, especially where the concurrence of slow water exchange and steady wind direction exists.

  1. Selective inhibition of toxic cyanobacteria by β-carboline-containing bacterium Bacillus flexus isolated from Saudi freshwaters.

    PubMed

    Alamri, Saad A; Mohamed, Zakaria A

    2013-10-01

    A bacterial strain SSZ01 isolated from a eutrophic lake in Saudi Arabia dominated by cyanobacterial blooms, showed an antialgal activity against cyanobacteria species. Based on the analysis of the 16S rDNA gene sequence, the isolated strain (SSZ01) most likely belonged to the genus Bacillus with a 99% similarity to Bacillus flexus strain EMGA5. The thin layer chromatography (TLC) analysis of the ethyl acetate extract of this bacterium revealed that this strain can produce harmine and norharmane compared to different β-carboline analog standards. Harmine and norharmane were also detected in considerable amounts in bacterial growth medium, indicating a potential excretion of these compounds into the aquatic environment. The crude extract of Bacillus flexus as well as pure materials of harmine and norharmane inhibited the growth of tested species of cyanobacteria. However, the bacterial crude extract has a higher toxicity against tested species of cyanobacteria than harmine and norharmane. In addition, harmine was more toxic to cyanobacteria than norharmane. On the other hand, neither pure compounds of harmine and norharmane nor crude bacterial extract showed any antialgal activity against tested species of green algae. The results of the present study suggest that B. flexus SSZ01 or its crude extract containing harmine and norharmane could be a candidate for the selective control of cyanobacterial blooms without affecting other algal species. PMID:24235872

  2. Protein translocation and thylakoid biogenesis in cyanobacteria.

    PubMed

    Frain, Kelly M; Gangl, Doris; Jones, Alexander; Zedler, Julie A Z; Robinson, Colin

    2016-03-01

    Cyanobacteria exhibit a complex form of membrane differentiation that sets them apart from most bacteria. Many processes take place in the plasma membrane, but photosynthetic light capture, electron transport and ATP synthesis take place in an abundant internal thylakoid membrane. This review considers how this system of subcellular compartmentalisation is maintained, and how proteins are directed towards the various subcompartments--specifically the plasma membrane, periplasm, thylakoid membrane and thylakoid lumen. The involvement of Sec-, Tat- and signal recognition particle- (SRP)-dependent protein targeting pathways is discussed, together with the possible involvement of a so-called 'spontaneous' pathway for the insertion of membrane proteins, previously characterised for chloroplast thylakoid membrane proteins. An intriguing aspect of cyanobacterial cell biology is that most contain only a single set of genes encoding Sec, Tat and SRP components, yet the proteomes of the plasma and thylakoid membranes are very different. The implications for protein sorting mechanisms are considered. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux.

  3. Photobiological production of hydrogen using cyanobacteria

    SciTech Connect

    Borthakur, D.; McKinley, K.R.; Bylina, E.J.

    1995-09-01

    Cyanobacteria are capable of generating hydrogen using sunlight and water. In both Spirulina and Anabaena, there is a soluble reversible hydrogenase that is involved in hydrogen evolution under anaerobic conditions in the dark. In addition, the nitrogen-fixing cyanobacterium Anabaena produces hydrogen as a by-product of nitrogen fixation. Most of this hydrogen is recaptured by a membrane-bound uptake hydrogenase present in Anabaena cells. Experiments have continued to develop a gene transfer system in Spirulina in preparation for improved hydrogen production via genetic manipulation of the reversible hydrogenase. We have identified and characterized four restriction enzymes in Spirulina and cloned the genes for two methylases that protect their own DNA from cleavage by restriction enzymes. We have also cloned and sequenced parts of hupB and hupM genes involved in the synthesis of uptake hydrogenase in Anabaena. Successful cloning of these hup genes represents an important and necessary step in our project because this will enable us to construct Anabaena strains with enhanced hydrogen production ability by disrupting the hup genes involved in hydrogen uptake. We are also setting up a bio-reactor to determine the amount of hydrogen released by different Spirulina and Anabaena strains under different physiological conditions.

  4. A Mechanism of Energy Dissipation in Cyanobacteria

    PubMed Central

    Berera, Rudi; van Stokkum, Ivo H.M.; d'Haene, Sandrine; Kennis, John T.M.; van Grondelle, Rienk; Dekker, Jan P.

    2009-01-01

    When grown under a variety of stress conditions, cyanobacteria express the isiA gene, which encodes the IsiA pigment-protein complex. Overexpression of the isiA gene under iron-depletion stress conditions leads to the formation of large IsiA aggregates, which display remarkably short fluorescence lifetimes and thus a strong capacity to dissipate energy. In this work we investigate the underlying molecular mechanism responsible for chlorophyll fluorescence quenching. Femtosecond transient absorption spectroscopy allowed us to follow the process of energy dissipation in real time. The light energy harvested by chlorophyll pigments migrated within the system and eventually reaches a quenching site where the energy is transferred to a carotenoid-excited state, which dissipates it by decaying to the ground state. We compare these findings with those obtained for the main light-harvesting complex in green plants (light-harvesting complex II) and artificial light-harvesting antennas, and conclude that all of these systems show the same mechanism of energy dissipation, i.e., one or more carotenoids act as energy dissipators by accepting energy via low-lying singlet-excited S1 states and dissipating it as heat. PMID:19289052

  5. Nitrogen fixed by cyanobacteria is utilized by deposit-feeders.

    PubMed

    Karlson, Agnes M L; Gorokhova, Elena; Elmgren, Ragnar

    2014-01-01

    Benthic communities below the photic zone depend for food on allochthonous organic matter derived from seasonal phytoplankton blooms. In the Baltic Sea, the spring diatom bloom is considered the most important input of organic matter, whereas the contribution of the summer bloom dominated by diazotrophic cyanobacteria is less understood. The possible increase in cyanobacteria blooms as a consequence of eutrophication and climate change calls for evaluation of cyanobacteria effects on benthic community functioning and productivity. Here, we examine utilization of cyanobacterial nitrogen by deposit-feeding benthic macrofauna following a cyanobacteria bloom at three stations during two consecutive years and link these changes to isotopic niche and variations in body condition (assayed as C:N ratio) of the animals. Since nitrogen-fixing cyanobacteria have δ(15)N close to -2‰, we expected the δ(15)N in the deposit-feeders to decrease after the bloom if their assimilation of cyanobacteria-derived nitrogen was substantial. We also expected the settled cyanobacteria with their associated microheterotrophic community and relatively high nitrogen content to increase the isotopic niche area, trophic diversity and dietary divergence between individuals (estimated as the nearest neighbour distance) in the benthic fauna after the bloom. The three surface-feeding species (Monoporeia affinis, Macoma balthica and Marenzelleria arctia) showed significantly lower δ(15)N values after the bloom, while the sub-surface feeder Pontoporeia femorata did not. The effect of the bloom on isotopic niche varied greatly between stations; populations which increased niche area after the bloom had better body condition than populations with reduced niche, regardless of species. Thus, cyanobacterial nitrogen is efficiently integrated into the benthic food webs in the Baltic, with likely consequences for their functioning, secondary production, transfer efficiency, trophic interactions, and

  6. Controlling Harmful Cyanobacteria: Taxa-Specific Responses of Cyanobacteria to Grazing by Large-Bodied Daphnia in a Biomanipulation Scenario.

    PubMed

    Urrutia-Cordero, Pablo; Ekvall, Mattias K; Hansson, Lars-Anders

    2016-01-01

    Lake restoration practices based on reducing fish predation and promoting the dominance of large-bodied Daphnia grazers (i.e., biomanipulation) have been the focus of much debate due to inconsistent success in suppressing harmful cyanobacterial blooms. While most studies have explored effects of large-bodied Daphnia on cyanobacterial growth at the community level and/or on few dominant species, predictions of such restoration practices demand further understanding on taxa-specific responses in diverse cyanobacterial communities. In order to address these questions, we conducted three grazing experiments during summer in a eutrophic lake where the natural phytoplankton community was exposed to an increasing gradient in biomass of the large-bodied Daphnia magna. This allowed evaluating taxa-specific responses of cyanobacteria to Daphnia grazing throughout the growing season in a desired biomanipulation scenario with limited fish predation. Total cyanobacterial and phytoplankton biomasses responded negatively to Daphnia grazing both in early and late summer, regardless of different cyanobacterial densities. Large-bodied Daphnia were capable of suppressing the abundance of Aphanizomenon, Dolichospermum, Microcystis and Planktothrix bloom-forming cyanobacteria. However, the growth of the filamentous Dolichospermum crassum was positively affected by grazing during a period when this cyanobacterium dominated the community. The eutrophic lake was subjected to biomanipulation since 2005 and nineteen years of lake monitoring data (1996-2014) revealed that reducing fish predation increased the mean abundance (50%) and body-size (20%) of Daphnia, as well as suppressed the total amount of nutrients and the growth of the dominant cyanobacterial taxa, Microcystis and Planktothrix. Altogether our results suggest that lake restoration practices solely based on grazer control by large-bodied Daphnia can be effective, but may not be sufficient to control the overgrowth of all

  7. Controlling Harmful Cyanobacteria: Taxa-Specific Responses of Cyanobacteria to Grazing by Large-Bodied Daphnia in a Biomanipulation Scenario.

    PubMed

    Urrutia-Cordero, Pablo; Ekvall, Mattias K; Hansson, Lars-Anders

    2016-01-01

    Lake restoration practices based on reducing fish predation and promoting the dominance of large-bodied Daphnia grazers (i.e., biomanipulation) have been the focus of much debate due to inconsistent success in suppressing harmful cyanobacterial blooms. While most studies have explored effects of large-bodied Daphnia on cyanobacterial growth at the community level and/or on few dominant species, predictions of such restoration practices demand further understanding on taxa-specific responses in diverse cyanobacterial communities. In order to address these questions, we conducted three grazing experiments during summer in a eutrophic lake where the natural phytoplankton community was exposed to an increasing gradient in biomass of the large-bodied Daphnia magna. This allowed evaluating taxa-specific responses of cyanobacteria to Daphnia grazing throughout the growing season in a desired biomanipulation scenario with limited fish predation. Total cyanobacterial and phytoplankton biomasses responded negatively to Daphnia grazing both in early and late summer, regardless of different cyanobacterial densities. Large-bodied Daphnia were capable of suppressing the abundance of Aphanizomenon, Dolichospermum, Microcystis and Planktothrix bloom-forming cyanobacteria. However, the growth of the filamentous Dolichospermum crassum was positively affected by grazing during a period when this cyanobacterium dominated the community. The eutrophic lake was subjected to biomanipulation since 2005 and nineteen years of lake monitoring data (1996-2014) revealed that reducing fish predation increased the mean abundance (50%) and body-size (20%) of Daphnia, as well as suppressed the total amount of nutrients and the growth of the dominant cyanobacterial taxa, Microcystis and Planktothrix. Altogether our results suggest that lake restoration practices solely based on grazer control by large-bodied Daphnia can be effective, but may not be sufficient to control the overgrowth of all

  8. Controlling Harmful Cyanobacteria: Taxa-Specific Responses of Cyanobacteria to Grazing by Large-Bodied Daphnia in a Biomanipulation Scenario

    PubMed Central

    Urrutia-Cordero, Pablo; Ekvall, Mattias K.; Hansson, Lars-Anders

    2016-01-01

    Lake restoration practices based on reducing fish predation and promoting the dominance of large-bodied Daphnia grazers (i.e., biomanipulation) have been the focus of much debate due to inconsistent success in suppressing harmful cyanobacterial blooms. While most studies have explored effects of large-bodied Daphnia on cyanobacterial growth at the community level and/or on few dominant species, predictions of such restoration practices demand further understanding on taxa-specific responses in diverse cyanobacterial communities. In order to address these questions, we conducted three grazing experiments during summer in a eutrophic lake where the natural phytoplankton community was exposed to an increasing gradient in biomass of the large-bodied Daphnia magna. This allowed evaluating taxa-specific responses of cyanobacteria to Daphnia grazing throughout the growing season in a desired biomanipulation scenario with limited fish predation. Total cyanobacterial and phytoplankton biomasses responded negatively to Daphnia grazing both in early and late summer, regardless of different cyanobacterial densities. Large-bodied Daphnia were capable of suppressing the abundance of Aphanizomenon, Dolichospermum, Microcystis and Planktothrix bloom-forming cyanobacteria. However, the growth of the filamentous Dolichospermum crassum was positively affected by grazing during a period when this cyanobacterium dominated the community. The eutrophic lake was subjected to biomanipulation since 2005 and nineteen years of lake monitoring data (1996–2014) revealed that reducing fish predation increased the mean abundance (50%) and body-size (20%) of Daphnia, as well as suppressed the total amount of nutrients and the growth of the dominant cyanobacterial taxa, Microcystis and Planktothrix. Altogether our results suggest that lake restoration practices solely based on grazer control by large-bodied Daphnia can be effective, but may not be sufficient to control the overgrowth of all

  9. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

    PubMed Central

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-01-01

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria. PMID:25009182

  10. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

    NASA Astrophysics Data System (ADS)

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-07-01

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria.

  11. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria.

    PubMed

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-07-29

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria.

  12. Weather variability, sunspots, and the blooms of cyanobacteria.

    PubMed

    Hu, Wenbiao; Connell, Des; Mengersen, Kerrie; Tong, Shilu

    2009-03-01

    The roles of weather variability and sunspots in the occurrence of cyanobacteria blooms, were investigated using cyanobacteria cell data collected from the Fred Haigh Dam, Queensland, Australia. Time series generalized linear model and classification and regression tree (CART) model were used in the analysis. Data on notified cell numbers of cyanobacteria and weather variables over the periods 2001 and 2005 were provided by the Australian Department of Natural Resources and Water, and Australian Bureau of Meteorology, respectively. The results indicate that monthly minimum temperature (relative risk [RR]: 1.13, 95% confidence interval [CI]: 1.02-1.25) and rainfall (RR: 1.11; 95% CI: 1.03-1.20) had a positive association, but relative humidity (RR: 0.94; 95% CI: 0.91-0.98) and wind speed (RR: 0.90; 95% CI: 0.82-0.98) were negatively associated with the cyanobacterial numbers, after adjustment for seasonality and auto-correlation. The CART model showed that the cyanobacteria numbers were best described by an interaction between minimum temperature, relative humidity, and sunspot numbers. When minimum temperature exceeded 18 degrees C and relative humidity was under 66%, the number of cyanobacterial cells rose by 2.15-fold. We conclude that weather variability and sunspot activity may affect cyanobacteria blooms in dams.

  13. Optimization of variable fluorescence measurements of phytoplankton communities with cyanobacteria.

    PubMed

    Simis, Stefan G H; Huot, Yannick; Babin, Marcel; Seppälä, Jukka; Metsamaa, Liisa

    2012-04-01

    Excitation-emission fluorescence matrices of phytoplankton communities were simulated from laboratory-grown algae and cyanobacteria cultures, to define the optical configurations of theoretical fluorometers that either minimize or maximize the representation of these phytoplankton groups in community variable fluorescence measurements. Excitation sources that match the photosystem II (PSII) action spectrum of cyanobacteria do not necessarily lead to equal representation of cyanobacteria in community fluorescence. In communities with an equal share of algae and cyanobacteria, inducible PSII fluorescence in algae can be retrieved from community fluorescence under blue excitation (450-470 nm) with high accuracy (R (2) = 1.00). The highest correlation between community and cyanobacterial variable fluorescence is obtained under orange-red excitation in the 590-650 nm range (R (2) = 0.54). Gaussian band decomposition reveals that in the presence of cyanobacteria, the emission detection slit must be narrow (up to 10 nm) and centred on PSII chlorophyll-a emission (~683 nm) to avoid severe dampening of the signal by weakly variable phycobilisomal fluorescence and non-variable photosystem I fluorescence. When these optimizations of the optical configuration of the fluorometer are followed, both cyanobacterial and algal cultures in nutrient replete exponential growth exhibit values of the maximum quantum yield of charge separation in PSII in the range of 0.65-0.7.

  14. Cellular interactions: lessons from the nitrogen-fixing cyanobacteria.

    PubMed

    Thompson, Anne W; Zehr, Jonathan P

    2013-12-01

    Marine nitrogen-fixing cyanobacteria play a central role in the open-ocean microbial community by providing fixed nitrogen (N) to the ocean from atmospheric dinitrogen (N2 ) gas. Once thought to be dominated by one genus of cyanobacteria, Trichodesmium, it is now clear that marine N2 -fixing cyanobacteria in the open ocean are more diverse, include several previously unknown symbionts, and are geographically more widespread than expected. The next challenge is to understand the ecological implications of this genetic and phenotypic diversity for global oceanic N cycling. One intriguing aspect of the cyanobacterial N2 fixers ecology is the range of cellular interactions they engage in, either with cells of their own species or with photosynthetic protists. From organelle-like integration with the host cell to a free-living existence, N2 -fixing cyanobacteria represent the range of types of interactions that occur among microbes in the open ocean. Here, we review what is known about the cellular interactions carried out by marine N2 -fixing cyanobacteria and where future work can help. Discoveries related to the functional roles of these specialized cells in food webs and the microbial community will improve how we interpret their distribution and abundance patterns and contributions to global N and carbon (C) cycles.

  15. Alleviation of high light-induced photoinhibition in cyanobacteria by artificially conferred biosilica shells.

    PubMed

    Xiong, Wei; Yang, Zhou; Zhai, Hailei; Wang, Guangchuan; Xu, Xurong; Ma, Weimin; Tang, Ruikang

    2013-09-01

    Bioinspired by diatoms, biomimetic silicification confers an artificial shell on cyanobacteria to alleviate photoinhibition; thus, the photosynthesis of the resulting cyanobacteria@SiO2 becomes more efficient under high light conditions.

  16. Expanding models of lake trophic state to predict cyanobacteria in lakes

    EPA Science Inventory

    Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chlor...

  17. Expanding Models of Lake Trophic State to Predict Cyanobacteria in Lakes: A Data Mining Approach

    EPA Science Inventory

    Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chloro...

  18. Phylogeny of culturable cyanobacteria from Brazilian mangroves.

    PubMed

    Silva, Caroline Souza Pamplona; Genuário, Diego Bonaldo; Vaz, Marcelo Gomes Marçal Vieira; Fiore, Marli Fátima

    2014-03-01

    The cyanobacterial community from Brazilian mangrove ecosystems was examined using a culture-dependent method. Fifty cyanobacterial strains were isolated from soil, water and periphytic samples collected from Cardoso Island and Bertioga mangroves using specific cyanobacterial culture media. Unicellular, homocytous and heterocytous morphotypes were recovered, representing five orders, seven families and eight genera (Synechococcus, Cyanobium, Cyanobacterium, Chlorogloea, Leptolyngbya, Phormidium, Nostoc and Microchaete). All of these novel mangrove strains had their 16S rRNA gene sequenced and BLAST analysis revealed sequence identities ranging from 92.5 to 99.7% when they were compared with other strains available in GenBank. The results showed a high variability of the 16S rRNA gene sequences among the genotypes that was not associated with the morphologies observed. Phylogenetic analyses showed several branches formed exclusively by some of these novel 16S rRNA gene sequences. BLAST and phylogeny analyses allowed for the identification of Nodosilinea and Oxynema strains, genera already known to exhibit poor morphological diacritic traits. In addition, several Nostoc and Leptolyngbya morphotypes of the mangrove strains may represent new generic entities, as they were distantly affiliated with true genera clades. The presence of non-ribosomal peptide synthetase, polyketide synthase, microcystin and saxitoxin genes were detected in 20.5%, 100%, 37.5% and 33.3%, respectively, of the 44 tested isolates. A total of 134 organic extracts obtained from 44 strains were tested against microorganisms, and 26% of the extracts showed some antimicrobial activity. This is the first polyphasic study of cultured cyanobacteria from Brazilian mangrove ecosystems using morphological, genetic and biological approaches.

  19. Response of cyanobacteria to low atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Qin, Lifeng; Yu, Qingni; Ai, Weidang; Tang, Yongkang; Ren, Jin; Guo, Shuangsheng

    2014-10-01

    Maintaining a low pressure environment in a controlled ecological life support system would reduce the technological complexity and resupply cost in the course of the construction of a future manned lunar base. To estimate the effect of a hypobaric environment in a lunar base on biological components, such as higher plants, microbes, and algae, cyanobacteria was used as the model by determining their response of growth, morphology, and physiology when exposed to half of standard atmospheric pressure for 16 days (brought back to standard atmospheric pressure 30 minutes every two days for sampling). The results indicated that the decrease of atmospheric pressure from 100 kPa to 50 kPa reduced the growth rates of Microcystis aeruginosa, Merismopedia sp., Anabaena sp. PCC 7120, and Anabaena flos-aquae. The ratio of carotenoid to chlorophyll a content in the four tested strains increased under low pressure conditions compared to ambient conditions, resulting from the decrease of chlorophyll a and the increase of carotenoid in the cells. Moreover, low pressure induced the reduction of the phycocyanin content in Microcystis aeruginosa, Anabaena sp. PCC 7120, and Anabaena flos-aquae. The result from the ultrastructure observed using SEM indicated that low pressure promoted the production of more extracellular polymeric substances (EPSs) compared to ambient conditions. The results implied that the low pressure environment of 50 kPa in a future lunar base would induce different effects on biological components in a CELSS, which must be considered during the course of designing a future lunar base. The results will be a reference for exploring the response of other biological components, such as plants, microbes, and animals, living in the life support system of a lunar base.

  20. Phylogeny of culturable cyanobacteria from Brazilian mangroves.

    PubMed

    Silva, Caroline Souza Pamplona; Genuário, Diego Bonaldo; Vaz, Marcelo Gomes Marçal Vieira; Fiore, Marli Fátima

    2014-03-01

    The cyanobacterial community from Brazilian mangrove ecosystems was examined using a culture-dependent method. Fifty cyanobacterial strains were isolated from soil, water and periphytic samples collected from Cardoso Island and Bertioga mangroves using specific cyanobacterial culture media. Unicellular, homocytous and heterocytous morphotypes were recovered, representing five orders, seven families and eight genera (Synechococcus, Cyanobium, Cyanobacterium, Chlorogloea, Leptolyngbya, Phormidium, Nostoc and Microchaete). All of these novel mangrove strains had their 16S rRNA gene sequenced and BLAST analysis revealed sequence identities ranging from 92.5 to 99.7% when they were compared with other strains available in GenBank. The results showed a high variability of the 16S rRNA gene sequences among the genotypes that was not associated with the morphologies observed. Phylogenetic analyses showed several branches formed exclusively by some of these novel 16S rRNA gene sequences. BLAST and phylogeny analyses allowed for the identification of Nodosilinea and Oxynema strains, genera already known to exhibit poor morphological diacritic traits. In addition, several Nostoc and Leptolyngbya morphotypes of the mangrove strains may represent new generic entities, as they were distantly affiliated with true genera clades. The presence of non-ribosomal peptide synthetase, polyketide synthase, microcystin and saxitoxin genes were detected in 20.5%, 100%, 37.5% and 33.3%, respectively, of the 44 tested isolates. A total of 134 organic extracts obtained from 44 strains were tested against microorganisms, and 26% of the extracts showed some antimicrobial activity. This is the first polyphasic study of cultured cyanobacteria from Brazilian mangrove ecosystems using morphological, genetic and biological approaches. PMID:24461713

  1. A Novel, Poly(Ethyl Ethylene Ether) Inhibitor to Trypsin from Marine Cyanobacteria, Lyngbya confervoides.

    PubMed

    Devi, Ambika; Prasanth, Shankar; Murugesh, Easwaran; Haridas, Karickal R; Sabu, Abdulhameed; Haridas, Madhathilkovilakathu

    2016-03-01

    A novel, poly(ethyl ethylene ether) inhibitor to trypsin was purified from marine cyanobacteria, Lyngbya confervoides from the coastal areas of Thalassery, North Kerala. The kinetics and the thermodynamic parameters of its interactions with the enzyme were also studied. It was demonstrated that the substrate binding, catalytic triad of the enzyme could be blocked by the inhibitor, as expressed by molecular simulation studies. The study also showed that the cyanobacterial group could prove to be a potential source of novel enzyme inhibitors for various applications.

  2. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    PubMed Central

    Pade, Nadin; Hagemann, Martin

    2014-01-01

    The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants. PMID:25551682

  3. Exploring Marine Cyanobacteria for Lead Compounds of Pharmaceutical Importance

    PubMed Central

    Uzair, Bushra; Tabassum, Sobia; Rasheed, Madiha; Rehman, Saima Firdous

    2012-01-01

    The Ocean, which is called the “mother of origin of life,” is also the source of structurally unique natural products that are mainly accumulated in living organisms. Cyanobacteria are photosynthetic prokaryotes used as food by humans. They are excellent source of vitamins and proteins vital for life. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immunodeficiency syndrome (AIDS), arthritis, and so forth, while other compounds have been developed as analgesics or to treat inflammation, and so forth. They produce a large variety of bioactive compounds, including substances with anticancer and antiviral activity, UV protectants, specific inhibitors of enzymes, and potent hepatotoxins and neurotoxins. Many cyanobacteria produce compounds with potent biological activities. This paper aims to showcase the structural diversity of marine cyanobacterial secondary metabolites with a comprehensive coverage of alkaloids and other applications of cyanobacteria. PMID:22545008

  4. Cyanobacteria and ultraviolet radiation (UVR) stress: mitigation strategies.

    PubMed

    Singh, Shailendra P; Häder, Donat-P; Sinha, Rajeshwar P

    2010-04-01

    Cyanobacteria are primitive photosynthetic oxygen-evolving prokaryotes that appeared on the Earth when there was no ozone layer to protect them from damaging ultraviolet radiation (UVR). UVR has both direct and indirect effects on the cyanobacteria due to absorption by biomolecules and UVR-induced oxidative stress, respectively. However, these organisms have developed several lines of mitigation strategies/defense mechanisms such as avoidance, scavenging, screening, repair and programmed cell death to counteract the damaging effects of UVR. This review presents an update on the effects of UVR on cyanobacteria and the defense mechanisms employed by these prokaryotes to withstand UVR stress. In addition, recent developments in the field of molecular biology of UV-absorbing compounds such as mycosporine-like amino acids and scytonemin, are also added and the possible role of programmed cell death, signal perception as well their transduction under UVR stress is being discussed.

  5. CyanoClust: comparative genome resources of cyanobacteria and plastids.

    PubMed

    Sasaki, Naobumi V; Sato, Naoki

    2010-01-01

    Cyanobacteria, which perform oxygen-evolving photosynthesis as do chloroplasts of plants and algae, are one of the best-studied prokaryotic phyla and one from which many representative genomes have been sequenced. Lack of a suitable comparative genomic database has been a problem in cyanobacterial genomics because many proteins involved in physiological functions such as photosynthesis and nitrogen fixation are not catalogued in commonly used databases, such as Clusters of Orthologous Proteins (COG). CyanoClust is a database of homolog groups in cyanobacteria and plastids that are produced by the program Gclust. We have developed a web-server system for the protein homology database featuring cyanobacteria and plastids. Database URL: http://cyanoclust.c.u-tokyo.ac.jp/.

  6. Is Monoglucosyldiacylglycerol a Precursor to Monogalactosyldiacylglycerol in All Cyanobacteria?

    PubMed

    Sato, Naoki

    2015-10-01

    Monogalactosyldiacylglycerol (MGDG) is ubiquitous in the photosynthetic membranes of cyanobacteria and chloroplasts. It is synthesized by galactosylation of diacylglycerol (DAG) in the chloroplasts, whereas it is produced by epimerization of monoglucosyldiacylglycerol (GlcDG) in at least several cyanobacteria that have been analyzed such as Synechocystis sp. PCC 6803. A previous study, however, showed that the mgdE gene encoding the epimerase is absent in some cyanobacteria such as Gloeobacter violaceus, Thermosynechococcus elongatus and Acaryochloris marina. In addition, the N-terminal 'fatty acid hydroxylase' domain is lacking in the MgdE protein of Prochlorococcus marinus. These problems may cast doubt upon the general (or exclusive) role of MgdE in the epimerization of GlcDG to MGDG in cyanobacteria. In addition, GlcDG is usually present at a very low level, and the structural determination of endogenous GlcDG has not been accomplished with cyanobacterial samples. In this study, I determined the structure of GlcDG from Anabaena variabilis by (1)H- and (13)C-nuclear magnetic resonance (NMR) spectroscopy. I then showed that G. violaceus, T. elongatus, A. marina and P. marinus contain GlcDG. In all cases, GlcDG consisted of fewer unsaturated molecular species than MGDG, providing further evidence that GlcDG is a precursor to MGDG. The conversion of GlcDG to MGDG was also demonstrated by radiolabeling and chase experiments in G. violaceus and P. marinus. These results demonstrate that all the analyzed cyanobacteria contain GlcDG, which is converted to MGDG, and suggest that an alternative epimerase is required for MGDG synthesis in these cyanobacteria.

  7. Blue color formation of cyanobacteria with beta-cyclocitral.

    PubMed

    Harada, Ken-Ichi; Ozaki, Keiko; Tsuzuki, Sayaka; Kato, Hajime; Hasegawa, Masateru; Kuroda, Emilia K; Arii, Suzue; Tsuji, Kiyomi

    2009-11-01

    Volatile compounds, such as beta-cyclocitral, geosmin, and 2-methylisoborneol, from cyanobacteria showed a lytic activity against cyanobacteria. Particularly, beta-cyclocitral caused an interesting color change in the culture broth from green to blue during the lysis process. In the present study, the lytic behavior of various cyanobacteria with beta-cyclocitral was investigated, and a mechanism for the blue color formation was developed. beta-Cyclocitral lysed both the laboratory strains of any genera and bloom samples including many species of cyanobacteria, and caused the characteristic color change from green to blue. beta-Cyclocitral provided a characteristic behavior, such that the absorption maxima of chlorophyll-a and beta-carotene disappeared, but that of phycocyanin still remained after 12 h, which indicated that beta-cyclocitral decomposed chlorophyll-a and beta-carotene rapidly, so that the inherent colors from the tolerant water-soluble pigments became observable in the cultured broth. This phenomenon was confirmed by another experiment using Phormidium (NIES-611), which showed a pink color derived from phycoerythrin. beta-Cyclocitral was more easily oxidized when compared with similar aldehyde compounds, so that the pH of the solution quickly decreased to 4.5. An oxidation product of beta-cyclocitral in water solution was isolated and identified as 2,6,6-trimethylcyclohexene-1-carboxylic acid. This study provides support that beta-cyclocitral derived from cyanobacteria plays an important role in the lysis of cyanobacteria and participates in the blue color formation under natural conditions.

  8. A phycocyanin probe as a tool for monitoring cyanobacteria in freshwater bodies.

    PubMed

    Brient, Luc; Lengronne, Marion; Bertrand, Emilie; Rolland, Delphine; Sipel, Arnaud; Steinmann, Delphine; Baudin, Isabelle; Legeas, Michèle; Le Rouzic, Bertrand; Bormans, Myriam

    2008-02-01

    In many countries, the presence of cyanobacteria in freshwater bodies used for both drinking water and recreational purposes is under increasing public health attention. Water managers are considering how to implement monitoring that leads to a minimization of the risks incurred by the users of potentially contaminated sites. To address this question, this study involved assessing the performance of a submersible probe for measuring phycocyanin-specific fluorescence as a function of cyanobacterial biomass, with the aim of applying it as a tool for surveillance management. Its advantages and limits compared to more traditional analyses are discussed. The monitoring of cyanobacteria in the water bodies of western France was carried out using a minifluorimeter specific to the fluorescence of phycocyanin, a pigment specific to cyanobacteria. The results are compared with the analyses recommended by the World Health Organisation (chlorophyll a and cell counting). This study based on nearly 800 samples shows a significant correlation between the phycocyanin content and the cyanobacterial biomass, expressed as the number of cells per mL (R2 = 0.73). This submersible probe is simple and rapid to use, making it possible to take into account horizontal and vertical heterogeneities in the proliferation growth. In this way, we are able to detect at an early stage the conditions that could potentially lead to a risk, in order to start sampling. Due to its sensitivity, this tool proves suitable for monitoring aimed at reducing the risks incurred by the users of contaminated sites and launching preventative actions. The use of the phycocyanin probe provides an effective tool to complement traditional analyses of cyanobacterial presence. It is suggested that a surveillance protocol based on phycocyanin concentration can significantly improved the accuracy of the extent of cyanobacterial bloom development in the light of spatial and temporal variabilities associated with these

  9. Comparative metagenomics of toxic freshwater cyanobacteria bloom communities on two continents.

    PubMed

    Steffen, Morgan M; Li, Zhou; Effler, T Chad; Hauser, Loren J; Boyer, Gregory L; Wilhelm, Steven W

    2012-01-01

    Toxic cyanobacterial blooms have persisted in freshwater systems around the world for centuries and appear to be globally increasing in frequency and severity. Toxins produced by bloom-associated cyanobacteria can have drastic impacts on the ecosystem and surrounding communities, and bloom biomass can disrupt aquatic food webs and act as a driver for hypoxia. Little is currently known regarding the genomic content of the Microcystis strains that form blooms or the companion heterotrophic community associated with bloom events. To address these issues, we examined the bloom-associated microbial communities in single samples from Lake Erie (North America), Lake Tai (Taihu, China), and Grand Lakes St. Marys (OH, USA) using comparative metagenomics. Together the Cyanobacteria and Proteobacteria comprised >90% of each bloom bacterial community sample, although the dominant phylum varied between systems. Relative to the existing Microcystis aeruginosa NIES 843 genome, sequences from Lake Erie and Taihu revealed a number of metagenomic islands that were absent in the environmental samples. Moreover, despite variation in the phylogenetic assignments of bloom-associated organisms, the functional potential of bloom members remained relatively constant between systems. This pattern was particularly noticeable in the genomic contribution of nitrogen assimilation genes. In Taihu, the genetic elements associated with the assimilation and metabolism of nitrogen were predominantly associated with Proteobacteria, while these functions in the North American lakes were primarily contributed to by the Cyanobacteria. Our observations build on an emerging body of metagenomic surveys describing the functional potential of microbial communities as more highly conserved than that of their phylogenetic makeup within natural systems.

  10. Comparative metagenomics of toxic freshwater cyanobacteria bloom communities on two continents.

    PubMed

    Steffen, Morgan M; Li, Zhou; Effler, T Chad; Hauser, Loren J; Boyer, Gregory L; Wilhelm, Steven W

    2012-01-01

    Toxic cyanobacterial blooms have persisted in freshwater systems around the world for centuries and appear to be globally increasing in frequency and severity. Toxins produced by bloom-associated cyanobacteria can have drastic impacts on the ecosystem and surrounding communities, and bloom biomass can disrupt aquatic food webs and act as a driver for hypoxia. Little is currently known regarding the genomic content of the Microcystis strains that form blooms or the companion heterotrophic community associated with bloom events. To address these issues, we examined the bloom-associated microbial communities in single samples from Lake Erie (North America), Lake Tai (Taihu, China), and Grand Lakes St. Marys (OH, USA) using comparative metagenomics. Together the Cyanobacteria and Proteobacteria comprised >90% of each bloom bacterial community sample, although the dominant phylum varied between systems. Relative to the existing Microcystis aeruginosa NIES 843 genome, sequences from Lake Erie and Taihu revealed a number of metagenomic islands that were absent in the environmental samples. Moreover, despite variation in the phylogenetic assignments of bloom-associated organisms, the functional potential of bloom members remained relatively constant between systems. This pattern was particularly noticeable in the genomic contribution of nitrogen assimilation genes. In Taihu, the genetic elements associated with the assimilation and metabolism of nitrogen were predominantly associated with Proteobacteria, while these functions in the North American lakes were primarily contributed to by the Cyanobacteria. Our observations build on an emerging body of metagenomic surveys describing the functional potential of microbial communities as more highly conserved than that of their phylogenetic makeup within natural systems. PMID:22952848

  11. Discovery of symbiotic nitrogen-fixing cyanobacteria in corals.

    PubMed

    Lesser, Michael P; Mazel, Charles H; Gorbunov, Maxim Y; Falkowski, Paul G

    2004-08-13

    Colonies of the Caribbean coral Montastraea cavernosa exhibit a solar-stimulated orange-red fluorescence that is spectrally similar to a variety of fluorescent proteins expressed by corals. The source of this fluorescence is phycoerythrin in unicellular, nonheterocystis, symbiotic cyanobacteria within the host cells of the coral. The cyanobacteria coexist with the symbiotic dinoflagellates (zooxanthellae) of the coral and express the nitrogen-fixing enzyme nitrogenase. The presence of this prokaryotic symbiont in a nitrogen-limited zooxanthellate coral suggests that nitrogen fixation may be an important source of this limiting element for the symbiotic association.

  12. Application of cellular biosensors for detection of atypical toxic bioactivity in microcystin-containing cyanobacterial extracts.

    PubMed

    Mankiewicz-Boczek, Joanna; Karwaciak, Iwona; Ratajewski, Marcin; Gągała, Ilona; Jurczak, Tomasz; Zalewski, Maciej; Pułaski, Łukasz

    2015-11-01

    Despite the focus of most ecotoxicological studies on cyanobacteria on a select group of cyanotoxins, especially microcystins, a growing body of evidence points to the involvement of other cyanobacterial metabolites in deleterious health effects. In the present study, original, self-developed reporter gene-based cellular biosensors, detecting activation of the main human xenobiotic stress response pathways, PXR and NFkappaB, were applied to detect novel potentially toxic bioactivities in extracts from freshwater microcystin-producing cyanobacterial blooms. Crude and purified extracts from cyanobacteria containing varying levels of microcystins, and standard microcystin-LR were tested. Two cellular biosensor types applied in this study, called NHRTOX (detecting PXR activation) and OXIBIOS (detecting NFkappaB activation), successfully detected potentially toxic or immunomodulating bioactivities in cyanobacterial extracts. The level of biosensor activation was comparable to control cognate environmental toxins. Despite the fact that extracts were derived from microcystin-producing cyanobacterial blooms and contained active microcystins, biosensor-detected bioactivities were shown to be unrelated to microcystin levels. Experimental results suggest the involvement of environmental toxins (causing a response in NHRTOX) and lipopolysaccharides (LPS) or other cell wall components (causing a response in OXIBIOS) in the potentially harmful bioactivity of investigated extracts. These results demonstrate the need for further identification of cyanobacterial metabolites other than commonly studied cyanotoxins as sources of health risk, show the usefulness of cellular biosensors for this purpose and suggest a novel, more holistic approach to environmental monitoring. PMID:26398929

  13. Cyanobacteria HABs - Causes, Prevention, and Mitigation Workgroup Report.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyanobacteria (blue-green algae) are estimated to have evolved 3.5 billion years ago, at which time they began to add oxygen to the existing anaerobic atmosphere, actually changing the chemistry of the planet and allowing new life forms to evolve. These ubiquitous microbes are capable of tolerating ...

  14. BMAA extraction of cyanobacteria samples: which method to choose?

    PubMed

    Lage, Sandra; Burian, Alfred; Rasmussen, Ulla; Costa, Pedro Reis; Annadotter, Heléne; Godhe, Anna; Rydberg, Sara

    2016-01-01

    β-N-Methylamino-L-alanine (BMAA), a neurotoxin reportedly produced by cyanobacteria, diatoms and dinoflagellates, is proposed to be linked to the development of neurological diseases. BMAA has been found in aquatic and terrestrial ecosystems worldwide, both in its phytoplankton producers and in several invertebrate and vertebrate organisms that bioaccumulate it. LC-MS/MS is the most frequently used analytical technique in BMAA research due to its high selectivity, though consensus is lacking as to the best extraction method to apply. This study accordingly surveys the efficiency of three extraction methods regularly used in BMAA research to extract BMAA from cyanobacteria samples. The results obtained provide insights into possible reasons for the BMAA concentration discrepancies in previous publications. In addition and according to the method validation guidelines for analysing cyanotoxins, the TCA protein precipitation method, followed by AQC derivatization and LC-MS/MS analysis, is now validated for extracting protein-bound (after protein hydrolysis) and free BMAA from cyanobacteria matrix. BMAA biological variability was also tested through the extraction of diatom and cyanobacteria species, revealing a high variance in BMAA levels (0.0080-2.5797 μg g(-1) DW).

  15. Photoinhibition of cyanobacteria and its application in cultural heritage conservation.

    PubMed

    Hsieh, Paul; Pedersen, Jens Z; Bruno, Laura

    2014-01-01

    Light has bilateral effects on phototrophic organisms. As cyanobacteria in Roman hypogea are long acclimatized to dim environment, moderate intensity of illumination can be used to alleviate biodeterioration problems on the stone substrata. Moderate intensity of light inactivates cyanobacteria by causing photoinhibition, photobleaching and photodamage to the cells. The effectiveness of light depends not only on its intensity but also on the composition and pigmentation of the component cyanobacteria in the biofilms. Red light is the most effective for the species rich in phycocyanin and allophycocyanin, such as Leptolyngbya sp. and Scytonema julianum, whereas green light is effective to inhibit the species rich in phycoerythrin, like Oculatella subterranea. White light is effective to control the grayish and the black cyanobacteria, such as Symphyonemopsis sp. and Eucapsis sp. abundant in all of these pigments. Blue light is the least effective. 150 μmol photons m(-2)  s(-1) of blue light cannot cause biofilm damage while the same intensity of red, green or white irradiation for 14 days can severely damage the cyanobacterial cells in the biofilms due to ROS formation. Electron spin resonance spectroscopy detected the formation of radicals in different cyanobacterial cellular extracts exposed to 80 μmol photons m(-2)  s(-1) of light.

  16. Septal Junctions in Filamentous Heterocyst-Forming Cyanobacteria.

    PubMed

    Flores, Enrique; Herrero, Antonia; Forchhammer, Karl; Maldener, Iris

    2016-02-01

    In the filaments of heterocyst-forming cyanobacteria, septal junctions that traverse the septal peptidoglycan join adjacent cells, allowing intercellular communication. Perforations in the septal peptidoglycan have been observed, and proteins involved in the formation of such perforations and putative protein components of the septal junctions have been identified, but their relationships are debated.

  17. Common Freshwater Cyanobacteria Grow in 100% CO2

    NASA Astrophysics Data System (ADS)

    Thomas, David J.; Sullivan, Shannon L.; Price, Amanda L.; Zimmerman, Shawn M.

    2005-02-01

    Cyanobacteria and similar organisms produced most of the oxygen found in Earth's atmosphere, which implies that early photosynthetic organisms would have lived in an atmosphere that was rich in CO2 and poor in O2. We investigated the tolerance of several cyanobacteria to very high (>20 kPa) concentrations of atmospheric CO2. Cultures of Synechococcus PCC7942, Synechocystis PCC7942, Plectonema boryanum, and Anabaena sp. were grown in liquid culture sparged with CO2-enriched air. All four strains grew when transferred from ambient CO2 to 20 kPa partial pressure of CO2 (pCO2), but none of them tolerated direct transfer to 40 kPa pCO2. Synechococcus and Anabaena survived 101 kPa (100%) pCO2 when pressure was gradually increased by 15 kPa per day, and Plectonema actively grew under these conditions. All four strains grew in an anoxic atmosphere of 5 kPa pCO2 in N2. Strains that were sensitive to high CO2 were also sensitive to low initial pH (pH 5-6). However, low pH in itself was not sufficient to prevent growth. Although mechanisms of damage and survival are still under investigation, we have shown that modern cyanobacteria can survive under Earth's primordial conditions and that cyanobacteria-like organisms could have flourished under conditions on early Mars, which probably had an atmosphere similar to early Earth's.

  18. The cyanobacteria toxins, microcystins – emerging risks to human health

    EPA Science Inventory

    Dialysis patients appear to be at increased risk for exposure to cyanobacteria toxins; episodes of microcystin (MCYST) exposure via dialysate during 1996 and 2001 have been previously reported. During 2001, as many as 44 renal insufficiency patients were exposed to contaminated d...

  19. Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs

    USGS Publications Warehouse

    Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.; Bradley, Paul M.

    2013-01-01

    Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products.

  20. Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs

    USGS Publications Warehouse

    Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.

    2013-01-01

    Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability [1-3]. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions [3-6]. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns [7, 8]. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds [4-6, 7-10]. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products.

  1. Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs

    USGS Publications Warehouse

    Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.; Bradley, Paul M.

    2013-01-01

    Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability [1-3]. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions [3-6]. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns [7, 8]. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds [4-6, 7-10]. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products [9].

  2. Septal Junctions in Filamentous Heterocyst-Forming Cyanobacteria.

    PubMed

    Flores, Enrique; Herrero, Antonia; Forchhammer, Karl; Maldener, Iris

    2016-02-01

    In the filaments of heterocyst-forming cyanobacteria, septal junctions that traverse the septal peptidoglycan join adjacent cells, allowing intercellular communication. Perforations in the septal peptidoglycan have been observed, and proteins involved in the formation of such perforations and putative protein components of the septal junctions have been identified, but their relationships are debated. PMID:26748968

  3. Common freshwater cyanobacteria grow in 100% CO2.

    PubMed

    Thomas, David J; Sullivan, Shannon L; Price, Amanda L; Zimmerman, Shawn M

    2005-02-01

    Cyanobacteria and similar organisms produced most of the oxygen found in Earth's atmosphere, which implies that early photosynthetic organisms would have lived in an atmosphere that was rich in CO2 and poor in O2. We investigated the tolerance of several cyanobacteria to very high (>20 kPa) concentrations of atmospheric CO2. Cultures of Synechococcus PCC7942, Synechocystis PCC7942, Plectonema boryanum, and Anabaena sp. were grown in liquid culture sparged with CO2-enriched air. All four strains grew when transferred from ambient CO2 to 20 kPa partial pressure of CO2 (pCO2), but none of them tolerated direct transfer to 40 kPa pCO2. Synechococcus and Anabaena survived 101 kPa (100%) pCO2 when pressure was gradually increased by 15 kPa per day, and Plectonema actively grew under these conditions. All four strains grew in an anoxic atmosphere of 5 kPa pCO2 in N2. Strains that were sensitive to high CO2 were also sensitive to low initial pH (pH 5-6). However, low pH in itself was not sufficient to prevent growth. Although mechanisms of damage and survival are still under investigation, we have shown that modern cyanobacteria can survive under Earth's primordial conditions and that cyanobacteria-like organisms could have flourished under conditions on early Mars, which probably had an atmosphere similar to early Earth's. PMID:15711170

  4. Cyanobacteria and Cyanotoxins Occurrence and Removal from Five High-Risk Conventional Treatment Drinking Water Plants.

    PubMed

    Szlag, David C; Sinclair, James L; Southwell, Benjamin; Westrick, Judy A

    2015-06-12

    An environmental protection agency EPA expert workshop prioritized three cyanotoxins, microcystins, anatoxin-a, and cylindrospermopsin (MAC), as being important in freshwaters of the United States. This study evaluated the prevalence of potentially toxin producing cyanobacteria cell numbers relative to the presence and quantity of the MAC toxins in the context of this framework. Total and potential toxin producing cyanobacteria cell counts were conducted on weekly raw and finished water samples from utilities located in five US states. An Enzyme-Linked Immunosorbant Assay (ELISA) was used to screen the raw and finished water samples for microcystins. High-pressure liquid chromatography with a photodiode array detector (HPLC/PDA) verified microcystin concentrations and quantified anatoxin-a and cylindrospermopsin concentrations. Four of the five utilities experienced cyanobacterial blooms in their raw water. Raw water samples from three utilities showed detectable levels of microcystins and a fourth utility had detectable levels of both microcystin and cylindrospermopsin. No utilities had detectable concentrations of anatoxin-a. These conventional plants effectively removed the cyanobacterial cells and all finished water samples showed MAC levels below the detection limit by ELISA and HPLC/PDA.

  5. Rhythm of carbon and nitrogen fixation in unicellular cyanobacteria under turbulent and highly aerobic conditions.

    PubMed

    Krishnakumar, S; Gaudana, Sandeep B; Viswanathan, Ganesh A; Pakrasi, Himadri B; Wangikar, Pramod P

    2013-09-01

    Nitrogen fixing cyanobacteria are being increasingly explored for nitrogenase-dependent hydrogen production. Commercial success however will depend on the ability to grow these cultures at high cell densities. Photo-limitation at high cell densities leads to hindered photoautotrophic growth while turbulent conditions, which simulate flashing light effect, can lead to oxygen toxicity to the nitrogenase enzyme. Cyanothece sp. strain ATCC 51142, a known hydrogen producer, is reported to grow and fix nitrogen under moderately oxic conditions in shake flasks. In this study, we explore the growth and nitrogen fixing potential of this organism under turbulent conditions with volumetric oxygen mass transfer coefficient (KL a) values that are up to 20-times greater than in shake flasks. In a stirred vessel, the organism grows well in turbulent regime possibly due to a simulated flashing light effect with optimal growth at Reynolds number of approximately 35,000. A respiratory burst lasting for about 4 h creates anoxic conditions intracellularly with near saturating levels of dissolved oxygen in the extracellular medium. This is concomitant with complete exhaustion of intracellular glycogen storage and upregulation of nifH and nifX, the genes encoding proteins of the nitrogenase complex. Further, the rhythmic oscillations in exhaust gas CO2 and O2 profiles synchronize faithfully with those in biochemical parameters and gene expression thereby serving as an effective online monitoring tool. These results will have important implications in potential commercial success of nitrogenase-dependent hydrogen production by cyanobacteria.

  6. Cyanobacteria and Cyanotoxins Occurrence and Removal from Five High-Risk Conventional Treatment Drinking Water Plants

    PubMed Central

    Szlag, David C.; Sinclair, James L.; Southwell, Benjamin; Westrick, Judy A.

    2015-01-01

    An environmental protection agency EPA expert workshop prioritized three cyanotoxins, microcystins, anatoxin-a, and cylindrospermopsin (MAC), as being important in freshwaters of the United States. This study evaluated the prevalence of potentially toxin producing cyanobacteria cell numbers relative to the presence and quantity of the MAC toxins in the context of this framework. Total and potential toxin producing cyanobacteria cell counts were conducted on weekly raw and finished water samples from utilities located in five US states. An Enzyme-Linked Immunosorbant Assay (ELISA) was used to screen the raw and finished water samples for microcystins. High-pressure liquid chromatography with a photodiode array detector (HPLC/PDA) verified microcystin concentrations and quantified anatoxin-a and cylindrospermopsin concentrations. Four of the five utilities experienced cyanobacterial blooms in their raw water. Raw water samples from three utilities showed detectable levels of microcystins and a fourth utility had detectable levels of both microcystin and cylindrospermopsin. No utilities had detectable concentrations of anatoxin-a. These conventional plants effectively removed the cyanobacterial cells and all finished water samples showed MAC levels below the detection limit by ELISA and HPLC/PDA. PMID:26075379

  7. Species-dependence of cyanobacteria removal efficiency by different drinking water treatment processes.

    PubMed

    Zamyadi, Arash; Dorner, Sarah; Sauvé, Sébastien; Ellis, Donald; Bolduc, Anouka; Bastien, Christian; Prévost, Michèle

    2013-05-15

    Accumulation and breakthrough of several potentially toxic cyanobacterial species within drinking water treatment plants (DWTP) have been reported recently. The objectives of this project were to test the efficiency of different treatment barriers in cyanobacterial removal. Upon observation of cyanobacterial blooms, intensive sampling was conducted inside a full scale DWTP at raw water, clarification, filtration and oxidation processes. Samples were taken for microscopic speciation/enumeration and microcystins analysis. Total cyanobacteria cell numbers exceeded World Health Organisation and local alert levels in raw water (6,90,000 cells/mL). Extensive accumulation of cyanobacteria species in sludge beds and filters, and interruption of treatment were observed. Aphanizomenon cells were poorly coagulated and they were not trapped efficiently in the sludge. It was also demonstrated that Aphanizomenon cells passed through and were not retained over the filter. However, Microcystis, Anabaena, and Pseudanabaena cells were adequately removed by clarification and filtration processes. The breakthrough of non toxic cyanobacterial cells into DWTPs could also result in severe treatment disruption leading to plant shutdown. Application of intervention threshold values restricted to raw water does not take into consideration the major long term accumulation of potentially toxic cells in the sludge and the risk of toxins release. Thus, a sampling regime inside the plant adapted to cyanobacterial occurrence and intensity is recommended.

  8. Strategies for monitoring and managing mass populations of toxic cyanobacteria in recreational waters: a multi-interdisciplinary approach

    PubMed Central

    2009-01-01

    Mass populations of toxin-producing cyanobacteria commonly develop in fresh-, brackish- and marine waters and effective strategies for monitoring and managing cyanobacterial health risks are required to safeguard animal and human health. A multi-interdisciplinary study, including two UK freshwaters with a history of toxic cyanobacterial blooms, was undertaken to explore different approaches for the identification, monitoring and management of potentially-toxic cyanobacteria and their associated risks. The results demonstrate that (i) cyanobacterial bloom occurrence can be predicted at a local- and national-scale using process-based and statistical models; (ii) cyanobacterial concentration and distribution in waterbodies can be monitored using remote sensing, but minimum detection limits need to be evaluated; (iii) cyanotoxins may be transferred to spray-irrigated root crops; and (iv) attitudes and perceptions towards risks influence the public's preferences and willingness-to-pay for cyanobacterial health risk reductions in recreational waters. PMID:20102578

  9. Spatial and temporal patterns in the seasonal distribution of toxic cyanobacteria in Western Lake Erie from 2002-2014.

    PubMed

    Wynne, Timothy T; Stumpf, Richard P

    2015-05-12

    Lake Erie, the world's tenth largest freshwater lake by area, has had recurring blooms of toxic cyanobacteria for the past two decades. These blooms pose potential health risks for recreation, and impact the treatment of drinking water. Understanding the timing and distribution of the blooms may aid in planning by local communities and resources managers. Satellite data provides a means of examining spatial patterns of the blooms. Data sets from MERIS (2002-2012) and MODIS (2012-2014) were analyzed to evaluate bloom patterns and frequencies. The blooms were identified using previously published algorithms to detect cyanobacteria (~25,000 cells mL-1), as well as a variation of these algorithms to account for the saturation of the MODIS ocean color bands. Images were binned into 10-day composites to reduce cloud and mixing artifacts. The 13 years of composites were used to determine frequency of presence of both detectable cyanobacteria and high risk (>100,000 cells mL-1) blooms. The bloom season according to the satellite observations falls within June 1 and October 31. Maps show the pattern of development and areas most commonly impacted during all years (with minor and severe blooms). Frequencies during years with just severe blooms (minor bloom years were not included in the analysis) were examined in the same fashion. With the annual forecasts of bloom severity, these frequency maps can provide public water suppliers and health departments with guidance on the timing of potential risk.

  10. Spatial and temporal patterns in the seasonal distribution of toxic cyanobacteria in Western Lake Erie from 2002-2014.

    PubMed

    Wynne, Timothy T; Stumpf, Richard P

    2015-05-01

    Lake Erie, the world's tenth largest freshwater lake by area, has had recurring blooms of toxic cyanobacteria for the past two decades. These blooms pose potential health risks for recreation, and impact the treatment of drinking water. Understanding the timing and distribution of the blooms may aid in planning by local communities and resources managers. Satellite data provides a means of examining spatial patterns of the blooms. Data sets from MERIS (2002-2012) and MODIS (2012-2014) were analyzed to evaluate bloom patterns and frequencies. The blooms were identified using previously published algorithms to detect cyanobacteria (~25,000 cells mL-1), as well as a variation of these algorithms to account for the saturation of the MODIS ocean color bands. Images were binned into 10-day composites to reduce cloud and mixing artifacts. The 13 years of composites were used to determine frequency of presence of both detectable cyanobacteria and high risk (>100,000 cells mL-1) blooms. The bloom season according to the satellite observations falls within June 1 and October 31. Maps show the pattern of development and areas most commonly impacted during all years (with minor and severe blooms). Frequencies during years with just severe blooms (minor bloom years were not included in the analysis) were examined in the same fashion. With the annual forecasts of bloom severity, these frequency maps can provide public water suppliers and health departments with guidance on the timing of potential risk. PMID:25985390

  11. Genetic and genomic analysis of RNases in model cyanobacteria.

    PubMed

    Cameron, Jeffrey C; Gordon, Gina C; Pfleger, Brian F

    2015-10-01

    Cyanobacteria are diverse photosynthetic microbes with the ability to convert CO2 into useful products. However, metabolic engineering of cyanobacteria remains challenging because of the limited resources for modifying the expression of endogenous and exogenous biochemical pathways. Fine-tuned control of protein production will be critical to optimize the biological conversion of CO2 into desirable molecules. Messenger RNAs (mRNAs) are labile intermediates that play critical roles in determining the translation rate and steady-state protein concentrations in the cell. The majority of studies on mRNA turnover have focused on the model heterotrophic bacteria Escherichia coli and Bacillus subtilis. These studies have elucidated many RNA modifying and processing enzymes and have highlighted the differences between these Gram-negative and Gram-positive bacteria, respectively. In contrast, much less is known about mRNA turnover in cyanobacteria. We generated a compendium of the major ribonucleases (RNases) and provide an in-depth analysis of RNase III-like enzymes in commonly studied and diverse cyanobacteria. Furthermore, using targeted gene deletion, we genetically dissected the RNases in Synechococcus sp. PCC 7002, one of the fastest growing and industrially attractive cyanobacterial strains. We found that all three cyanobacterial homologs of RNase III and a member of the RNase II/R family are not essential under standard laboratory conditions, while homologs of RNase E/G, RNase J1/J2, PNPase, and a different member of the RNase II/R family appear to be essential for growth. This work will enhance our understanding of native control of gene expression and will facilitate the development of an RNA-based toolkit for metabolic engineering in cyanobacteria.

  12. Carbon acquisition by Cyanobacteria: Mechanisms, Comparative Genomics and Evolution

    SciTech Connect

    Kaplan, Aaron; Hagemann, Martin; Bauwe, Hermann; Kahlon, Shira; Ogawa, Teruo

    2008-01-01

    In this chapter we mainly focus on the mechanisms of inorganic carbon uptake, photorespiration, and the regulation between the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. We identify the genes involved, their regulation and phylogeny. Living in an environment where the CO₂ concentration is considerably lower than required to saturate their carboxylating enzyme, ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), cyanobacteria acquired the CO₂ concentrating mechanism (CCM) that enables them to accumulate CO₂ at the carboxylation site. All the cyanobacteria examined to date are able to fix CO₂ into carbohydrates. However, in addition to variance in the range of physical growth conditions, cyanobacteria also vary substantially in their ability to consume organic carbon from their surroundings. Many strains are obligate photoautotrophs where the sole carbon source is CO₂, while others are able to perform photomixotrophic or even heterotrophic growth using a wide variety of organic substances (c.f. Rippka et al., 1979; Stal and Moezelaar, 1997b). Cyanobacteria constitute a unique case where the anabolic and catabolic carbohydrate metabolisms function in the same cellular compartment. In addition, the photosynthetic and respiratory electron transport pathways share components in the thylakoid membranes. Despite its importance to our understanding of cyanobacterial metabolism, little is known about the mechanisms involved in the shifts between photoautotrophic, heterotrophic and photomixotrophic modes of growth, and their regulation; between the different pathways of carbohydrate breakdown- glycolysis, fermentation, the oxidative pentose phosphate, the Krebs cycle and the photorespiratory pathways. In this chapter we shall briefly focus on recent advances in our understanding of the CCM and carbon metabolism in cyanobacteria.

  13. Carbon Acquisition by Cyanobacteria: Mechanisms, Comparative Genomics, and Evolution

    SciTech Connect

    Kaplan, Aaron; Hagemann, Martin; Bauwe, Hermann; Kahlon, Shira; Ogawa, Teruo

    2008-01-01

    In this chapter we mainly focus on the mechanisms of inorganic carbon uptake, photorespiration, and the regulation between the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. We identify the genes involved, their regulation and phylogeny. Living in an environment where the CO₂ concentration is considerably lower than required to saturate their carboxylating enzyme, ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), cyanobacteria acquired the CO₂ concentrating mechanism (CCM) that enables them to accumulate CO₂ at the carboxylation site. All the cyanobacteria examined to date are able to fix CO₂ into carbohydrates. However, in addition to variance in the range of physical growth conditions, cyanobacteria also vary substantially in their ability to consume organic carbon from their surroundings. Many strains are obligate photoautotrophs where the sole carbon source is CO₂, while others are able to perform photomixotrophic or even heterotrophic growth using a wide variety of organic substances (c.f. Rippka et al., 1979; Stal and Moezelaar, 1997b). Cyanobacteria constitute a unique case where the anabolic and catabolic carbohydrate metabolisms function in the same cellular compartment. In addition, the photosynthetic and respiratory electron transport pathways share components in the thylakoid membranes. Despite its importance to our understanding of cyanobacterial metabolism, little is known about the mechanisms involved in the shifts between photoautotrophic, heterotrophic and photomixotrophic modes of growth, and their regulation; between the different pathways of carbohydrate breakdown- glycolysis, fermentation, the oxidative pentose phosphate, the Krebs cycle and the photorespiratory pathways. In this chapter we shall briefly focus on recent advances in our understanding of the CCM and carbon metabolism in cyanobacteria.

  14. Desert Cyanobacteria under simulated space and Martian conditions

    NASA Astrophysics Data System (ADS)

    Billi, D.; Ghelardini, P.; Onofri, S.; Cockell, C. S.; Rabbow, E.; Horneck, G.

    2008-09-01

    The environment in space and on planets such as Mars, can be lethal to living organisms and high levels of tolerance to desiccation, cold and radiation are needed for survival: rock-inhabiting cyanobacteria belonging to the genus Chroococcidiopsis can fulfil these requirements [1]. These cyanobacteria constantly appear in the most extreme and dry habitats on Earth, including the McMurdo Dry Valleys (Antarctica) and the Atacama Desert (Chile), which are considered the closest terrestrial analogs of two Mars environmental extremes: cold and aridity. In their natural environment, these cyanobacteria occupy the last refuges for life inside porous rocks or at the stone-soil interfaces, where they survive in a dry, dormant state for prolonged periods. How desert strains of Chroococcidiopsis can dry without dying is only partially understood, even though experimental evidences support the existence of an interplay between mechanisms to avoid (or limit) DNA damage and repair it: i) desert strains of Chroococcidiopsis mend genome fragmentation induced by ionizing radiation [2]; ii) desiccation-survivors protect their genome from complete fragmentation; iii) in the dry state they show a survival to an unattenuated Martian UV flux greater than that of Bacillus subtilis spores [3], and even though they die following atmospheric entry after having orbited the Earth for 16 days [4], they survive to simulated shock pressures up to 10 GPa [5]. Recently additional experiments were carried out at the German Aerospace Center (DLR) of Cologne (Germany) in order to identify suitable biomarkers to investigate the survival of Chroococcidiopsis cells present in lichen-dominated communities, in view of their direct and long term space exposition on the International Space Station (ISS) in the framework of the LIchens and Fungi Experiments (LIFE, EXPOSEEuTEF, ESA). Multilayers of dried cells of strains CCMEE 134 (Beacon Valley, Antarctica), and CCMEE 123 (costal desert, Chile ), shielded by

  15. Quantitatively evaluating detoxification of the hepatotoxic microcystins through the glutathione and cysteine pathway in the cyanobacteria-eating bighead carp.

    PubMed

    He, Jun; Chen, Jun; Xie, Ping; Zhang, Dawen; Li, Guangyu; Wu, Laiyan; Zhang, Wei; Guo, Xiaochun; Li, Shangchun

    2012-07-15

    Glutathione (GSH) and cysteine (Cys) conjugation have long been recognized to be important in the detoxification of microcystins (MCs) in animal organs, however, studies quantitatively estimating this process are rare, especially those simultaneously determining multiple toxins and their metabolites. This paper, for the first time, simultaneously quantified MC-LR (leucine arginine), MC-RR (arginine arginine), MCLR-GSH/Cys and MCRR-GSH/Cys in the liver, kidney, intestine and muscle of the cyanobacteria-eating bighead carp i.p. injected with two doses of MCs using liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). MCLR-Cys and MCRR-Cys content were much higher in kidney than in liver, intestine and muscle, suggesting the organotropism to kidney, while MCLR-GSH and MCRR-GSH were always below the detection limit. Bighead carp effectively metabolized MC-LR and MC-RR into the cysteine conjugates in kidney, as the ratios of MCLR-Cys to MC-LR and MCRR-Cys to MC-RR reached as high as 9.04 and 19.10, respectively. MC-LR and MC-RR were excreted mostly in the form of MCLR/RR-Cys rather than MCLR/RR-GSH, while MCs-GSH might act as mid-metabolites and changed to the more stable MCs-Cys rapidly. Cysteine conjugation of MCs appears to be an important biochemical mechanism for the cyanobacteria-eating fish to resist toxic cyanobacteria. A comparison of such detoxification mechanisms between fish and mammals would be interesting in the future studies. PMID:22466356

  16. Inferring Properties of Ancient Cyanobacteria from Biogeochemical Activity and Genomes of Siderophilic Cyanobacteria

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Brown, I. I.; Tringe, S. G.; Thomas-Keprta, K. E.; Bryant, D. A.; Sarkisova, S. S.; Malley, K.; Sosa, O.; Klatt, C. G.; McKay, D. S.

    2010-01-01

    Interrelationships between life and the planetary system could have simultaneously left landmarks in genomes of microbes and physicochemical signatures in the lithosphere. Verifying the links between genomic features in living organisms and the mineralized signatures generated by these organisms will help to reveal traces of life on Earth and beyond. Among contemporary environments, iron-depositing hot springs (IDHS) may represent one of the most appropriate natural models [1] for insights into ancient life since organisms may have originated on Earth and probably Mars in association with hydrothermal activity [2,3]. IDHS also seem to be appropriate models for studying certain biogeochemical processes that could have taken place in the late Archean and,-or early Paleoproterozoic eras [4, 5]. It has been suggested that inorganic polyphosphate (PPi), in chains of tens to hundreds of phosphate residues linked by high-energy bonds, is environmentally ubiquitous and abundant [6]. Cyanobacteria (CB) react to increased heavy metal concentrations and UV by enhanced generation of PPi bodies (PPB) [7], which are believed to be signatures of life [8]. However, the role of PPi in oxygenic prokaryotes for the suppression of oxidative stress induced by high Fe is poorly studied. Here we present preliminary results of a new mechanism of Fe mineralization in oxygenic prokaryotes, the effect of Fe on the generation of PPi bodies in CB, as well as preliminary analysis of the diversity and phylogeny of proteins involved in the prevention of oxidative stress in phototrophs inhabiting IDHS.

  17. Application of in vivo measurements for the management of cyanobacteria breakthrough into drinking water treatment plants.

    PubMed

    Zamyadi, Arash; Dorner, Sarah; Ndong, Mouhamed; Ellis, Donald; Bolduc, Anouka; Bastien, Christian; Prévost, Michèle

    2014-02-01

    The increasing presence of potentially toxic cyanobacterial blooms in drinking water sources and within drinking water treatment plants (DWTPs) has been reported worldwide. The objectives of this study are to validate the application of in vivo probes for the detection and management of cyanobacteria breakthrough inside DWTPs, and to verify the possibility of treatment adjustment based on intensive real-time monitoring. In vivo phycocyanin YSI probes were used to monitor the fate of cyanobacteria in raw water, clarified water, filtered water, and chlorinated water in a full scale DWTP. Simultaneous samples were also taken for microscopic enumeration. The in vivo probe was successfully used to detect the incoming densities of high cyanobacterial cell number into the clarification process and their breakthrough into the filtered water. In vivo probes were used to trace the increase in floating cells over the clarifier, a robust sign of malfunction of the coagulation-sedimentation process. Pre-emptive treatment adjustments, based on in vivo probe monitoring, resulted in successful removal of cyanobacterial cells. The field results on validation of the probes with cyanobacterial bloom samples showed that the probe responses are highly linear and can be used to trigger alerts to take action.

  18. Are Known Cyanotoxins Involved in the Toxicity of Picoplanktonic and Filamentous North Atlantic Marine Cyanobacteria?

    PubMed Central

    Frazão, Bárbara; Martins, Rosário; Vasconcelos, Vitor

    2010-01-01

    Eight marine cyanobacteria strains of the genera Cyanobium, Leptolyngbya, Oscillatoria, Phormidium, and Synechococcus were isolated from rocky beaches along the Atlantic Portuguese central coast and tested for ecotoxicity. Strains were identified by morphological characteristics and by the amplification and sequentiation of the 16S rDNA. Bioactivity of dichloromethane, methanol and aqueous extracts was assessed by the Artemia salina bioassay. Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. Molecular analysis of the genes involved in the production of known cyanotoxins such as microcystins, nodularins and cylindrospermopsin was also performed. Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones. Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast. PMID:20631874

  19. Bioefficacy of novel cyanobacteria-amended formulations in suppressing damping off disease in tomato seedlings.

    PubMed

    Chaudhary, Vidhi; Prasanna, Radha; Nain, Lata; Dubey, S C; Gupta, Vishal; Singh, Rajendra; Jaggi, Seema; Bhatnagar, Ashok Kumar

    2012-12-01

    Biological control of plant pathogens is receiving increasing relevance, as compared to chemical methods, as they are eco-friendly, economical and indirectly improve plant quality and yield attributes. An investigation was undertaken to evaluate the potential of antagonistic cyanobacteria (Anabaena variabilis RPAN59 and A. oscillarioides RPAN69) fortified formulations for suppressing damping off disease in tomato seedlings challenged by the inoculation of a fungal consortium (Pythium debaryanum, Fusarium oxysporum lycopersici, Fusarium moniliforme and Rhizoctonia solani). Treatment with A. variabilis amended formulations recorded significantly higher plant growth parameters, than other treatments, including biological control (Trichoderma formulation) and chemical control (Thiram-Carbendazim). The A. variabilis amended compost-vermiculite and compost formulations exhibited 10-15 % lower disease severity and 40-50 % higher values than chemical and biological control treatments in terms of fresh weight and height of the plants. In future, in depth analyses regarding the mechanism involved in biocontrol by cyanobacteria and evaluation of these formulations under field conditions are proposed to be undertaken.

  20. Detection of cyanobacteria and methanogens embedded in Mars analogue minerals by the use of Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    de Vera, J.-P. P.; Böttger, U.; Fritz, J.; Weber, I.; Malaszkiewicz, J.; Serrano, P.; Meessen, J.; Ott, S.; Wagner, D.; Hübers, H.-W.

    2012-04-01

    RLS (Raman Laser Spectrometer - one of the Pasteur Payload Instruments onboard ExoMars 2018) will perform Raman measurements on Mars to identify organic compounds and mineral products as an indication of biological activity. The measurements will be performed on crushed powdered samples inside the Rover's ALD (Analytical Laboratory Drawer). Raman analytics with the same specifications as those onboard the future ExoMars mission are conducted to test their potential of identifying biological material on martian analogue material. Appropriate measurement parameters for the detection of biological material as well as for the determination of the mineral composition will be derived. In addition, we report on problems using Raman spectroscopy to discriminate cells of microorganisms from the mineral background. Two organisms are chosen as test candidates for potential life on Mars: cyanobacteria and methane producing archaea. Prokaryotes like archaea and bacteria appeared on early Earth at least 3.8 to 3.5 billion years ago (Gya). At this time on Mars the climate was more temperate and wet compared to the present day as inferred from geological evidence for liquid water on the ancient martian surface. Thus life might have developed under similar conditions as on Earth or might have been transferred from Earth (or vice versa). Methane is known to be present on Mars, although the origin (if geothermal or biological activity) is still unknown. Cyanobacteria and prokaryotes using photosystem I belong to the oldest microbes on Earth. These organisms use pigments such as scytonemin and β-carotene as UV protection. Especially β-carotene emits a strong Raman signal. Raman analytics are used for detection of biofilm forming cyanobacteria Nostoc commune strain on the below described Mars analogue mineral mixtures. N. commune is known to be resistant to desiccation, UV B radiation and low temperatures, and thus suitable as a candidate for a potential life form on Mars

  1. Mineralized Remains of Morphotypes of Filamentous Cyanobacteria in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.

    2005-01-01

    The quest for conclusive evidence of microfossils in meteorites has been elusive. One difficulty arises from the fact than many abiotic or inorganic microstructures, mineral grains, and coating artifacts can mimic the smaller representatives of the microbial world that possess very simple morphologies (unicellular cocci or bacilli). However, there exist a wide variety of large, filamentous trichomic prokaryotic microorganisms (cyanobacteria and sulfur bacteria) with sufficiently well known and complex morphologies that they can be recognized and are known to be of unquestionable biogenic origin. The taphonomic modes of fossilization and their of their life habits and processes frequently result in distinctive chemical biosignatures associated with carbonization, silicification, calcification, phosphatization and metal-binding properties of their cell-walls, trichomes, sheaths and extracellular polymeric substances (EPS). Strong differences of mineral concentrations in closely associated and visibly differentiated cellular microstructures provide strong evidence of biogenicity. This evidence is further enhanced by the detection of recognizable and distinct microstructures (e.g., uniseriate or multiseriate filaments, trichomes, sheaths, cells of proper sizes and size distributions) and growth characteristics (e.g., basal or apical cells, true or false branching of trichomes, tapered or uniform filaments, robust or thin sheaths) and reproductive and nitrogen fixation habits (e.g., baeocytes, hormogonia, akinetes and heterocysts), Microfossils of cyanobacteria and cyanobacterial mats and stromatolites have been recognized a described from many of the most ancient rocks on Earth. The crucial problem lies in developing valid protocols and methodologies for establishing that the putative microfossils are truly indigenous and not merely recent microbial contaminants. During the past several years, we have conducted Field Emission Scanning Electron Microscopy (FESEM

  2. Evolution of saxitoxin synthesis in cyanobacteria and dinoflagellates.

    PubMed

    Hackett, Jeremiah D; Wisecaver, Jennifer H; Brosnahan, Michael L; Kulis, David M; Anderson, Donald M; Bhattacharya, Debashish; Plumley, F Gerald; Erdner, Deana L

    2013-01-01

    Dinoflagellates produce a variety of toxic secondary metabolites that have a significant impact on marine ecosystems and fisheries. Saxitoxin (STX), the cause of paralytic shellfish poisoning, is produced by three marine dinoflagellate genera and is also made by some freshwater cyanobacteria. Genes involved in STX synthesis have been identified in cyanobacteria but are yet to be reported in the massive genomes of dinoflagellates. We have assembled comprehensive transcriptome data sets for several STX-producing dinoflagellates and a related non-toxic species and have identified 265 putative homologs of 13 cyanobacterial STX synthesis genes, including all of the genes directly involved in toxin synthesis. Putative homologs of four proteins group closely in phylogenies with cyanobacteria and are likely the functional homologs of sxtA, sxtG, and sxtB in dinoflagellates. However, the phylogenies do not support the transfer of these genes directly between toxic cyanobacteria and dinoflagellates. SxtA is split into two proteins in the dinoflagellates corresponding to the N-terminal portion containing the methyltransferase and acyl carrier protein domains and a C-terminal portion with the aminotransferase domain. Homologs of sxtB and N-terminal sxtA are present in non-toxic strains, suggesting their functions may not be limited to saxitoxin production. Only homologs of the C-terminus of sxtA and sxtG were found exclusively in toxic strains. A more thorough survey of STX+ dinoflagellates will be needed to determine if these two genes may be specific to SXT production in dinoflagellates. The A. tamarense transcriptome does not contain homologs for the remaining STX genes. Nevertheless, we identified candidate genes with similar predicted biochemical activities that account for the missing functions. These results suggest that the STX synthesis pathway was likely assembled independently in the distantly related cyanobacteria and dinoflagellates, although using some

  3. Development of a universal microarray based on the ligation detection reaction and 16S rrna gene polymorphism to target diversity of cyanobacteria.

    PubMed

    Castiglioni, Bianca; Rizzi, Ermanno; Frosini, Andrea; Sivonen, Kaarina; Rajaniemi, Pirjo; Rantala, Anne; Mugnai, Maria Angela; Ventura, Stefano; Wilmotte, Annick; Boutte, Christophe; Grubisic, Stana; Balthasart, Pierre; Consolandi, Clarissa; Bordoni, Roberta; Mezzelani, Alessandra; Battaglia, Cristina; De Bellis, Gianluca

    2004-12-01

    The cyanobacteria are photosynthetic prokaryotes of significant ecological and biotechnological interest, since they strongly contribute to primary production and are a rich source of bioactive compounds. In eutrophic fresh and brackish waters, their mass occurrences (water blooms) are often toxic and constitute a high potential risk for human health. Therefore, rapid and reliable identification of cyanobacterial species in complex environmental samples is important. Here we describe the development and validation of a microarray for the identification of cyanobacteria in aquatic environments. Our approach is based on the use of a ligation detection reaction coupled to a universal array. Probes were designed for detecting 19 cyanobacterial groups including Anabaena/Aphanizomenon, Calothrix, Cylindrospermopsis, Cylindrospermum, Gloeothece, halotolerants, Leptolyngbya, Palau Lyngbya, Microcystis, Nodularia, Nostoc, Planktothrix, Antarctic Phormidium, Prochlorococcus, Spirulina, Synechococcus, Synechocystis, Trichodesmium, and Woronichinia. These groups were identified based on an alignment of over 300 cyanobacterial 16S rRNA sequences. For validation of the microarrays, 95 samples (24 axenic strains from culture collections, 27 isolated strains, and 44 cloned fragments recovered from environmental samples) were tested. The results demonstrated a high discriminative power and sensitivity to 1 fmol of the PCR-amplified 16S rRNA gene. Accurate identification of target strains was also achieved with unbalanced mixes of PCR amplicons from different cyanobacteria and an environmental sample. Our universal array method shows great potential for rapid and reliable identification of cyanobacteria. It can be easily adapted to future development and could thus be applied both in research and environmental monitoring. PMID:15574913

  4. [Movement characteristics of Cyanobacteria under stress of water-lifting aeration].

    PubMed

    Sun, Xiu-Xiu; Cong, Hai-Bing; Gao, Zheng-Juan; Cui, Chao-Jie; Cao, Qian-Qian

    2014-05-01

    In order to study the impact of algae control mixing technology on the distribution characteristics and movement of Cyanobacteria, the floating and subsiding velocity of Cyanobacteria in Taihu Lake was measured under different conditions such as different illuminance, temperature and pressure. The Cyanobacteria showed strong propensity of floating under the illuminance from 1500 1x to 6000 1x. The Cyanobacteria particle with floating velocity of more than 0.8 cm.min-1 accounted for 58% under the illuminance of 1 500 1x. The floating velocity slowed down when the illuminance was lower than 1 500 1x or higher than 6 000 1x. In the temperature range of 8 to 25 Celsius degree, the Cyanobacteria floated and the floating velocity increased with temperature. The Cyanobacteria floated under the pressure of 0- 0. 1 MPa and the floating velocity slowed down as the pressure increased. Most Cyanobacteria were suspended in the water when the pressure reached 0. 2-0. 3 MPa and only a small part of the Cyanobacteria floated or settled. When the pressure reached 0. 4-0. 6 MPa, the Cyanobacteria notably settled and the subsiding velocity increased with the increase of pressure. The Cyanobacteria particles with subsiding velocity of more than 1.0 cm.min-1 accounted for 52.5% when the pressure was 0. 6 MPa. Gas vesicles bursted when the gas vesicles of the Cyanobacteria could not bear the external pressure. The buoyancy of the Cyanobacteria diminished until the floating force became smaller than its weight, causing the particles of the Cyanobacteria to settle. Under normal atmospheric pressure, the particle diameter was positively correlated to the floating velocity, while negatively correlated to the density. Under high pressure, the particle diameter was positively correlated to the subsiding velocity and the density.

  5. Raman Characterization of the UV-Protective Pigment Gloeocapsin and Its Role in the Survival of Cyanobacteria.

    PubMed

    Storme, Jean-Yves; Golubic, Stjepko; Wilmotte, Annick; Kleinteich, Julia; Velázquez, David; Javaux, Emmanuelle J

    2015-10-01

    Extracellular UV-screening pigments gloeocapsin and scytonemin present in the exopolysaccharide (EPS) envelopes of extremophilic cyanobacteria of freshwater and marine environments were studied by Raman spectroscopy and compared to their intracellular photosynthetic pigments. This Raman spectral analysis of the extracellular pigment gloeocapsin showed that it shared Raman spectral signatures with parietin, a radiation-protective pigment known in lichens. The UV-light spectra also show similarities. Gloeocapsin occurs in some cyanobacterial species, mostly with exclusion of scytonemin, indicating that these pigments have evolved in cyanobacteria as separate protective strategies. Both gloeocapsin and scytonemin are widely and species-specifically distributed in different cyanobacterial genera and families. The widespread occurrence of these pigments may suggest an early origin, while their detection by Raman spectroscopy makes them potential biosignatures for cyanobacteria in the fossil record and demonstrates the usefulness of nondestructive Raman spectroscopy analyses for the search for complex organics, including possible photosynthetic pigments, if preservable in early Earth and extraterrestrial samples. PMID:26406539

  6. Detection of toxin-producing cyanobacteria by use of paramagnetic beads for cell concentration and DNA purification.

    PubMed

    Rudi, K; Larsen, F; Jakobsen, K S

    1998-01-01

    Early detection of water blooms caused by potential toxin-producing cyanobacteria is important in environmental monitoring. We present a new nucleic acid-based method for detection of cyanobacteria in water that utilizes the same paramagnetic solid phase (beads) for both bacterial cell concentration and subsequent DNA purification. In the cell concentration step, the beads were attracted to a magnet after cell adsorption (in an alcohol- and salt-containing solution), and the supernatant was removed. For DNA purification, a buffer containing guanidine thiocyanate and Sarkosyl lysed the concentrated cells. The addition of alcohol precipitated the released DNA onto the same solid phase as was used for the cell concentration. Finally, to remove PCR inhibitors, the DNA was washed twice in alcohol while bound to the beads. All of the bead-DNA complex was used in the subsequent PCR amplification. The detection limit, as measured by 16S rDNA PCR amplification, was 50 cells in a 0.5-ml water sample, which is considerably lower than the limit (500 cells/ml) of toxic cyanobacteria tolerated in drinking water (New South Wales Blue-Green Algae Task Force, 1992). Testing of water from natural habitats showed a detection limit in the same range as that for the defined samples. The detection limits and the simplicity of the method (paramagnetic beads can be handled in automated systems) suggest that our method is suitable for routine environmental monitoring. PMID:9435059

  7. IM30 triggers membrane fusion in cyanobacteria and chloroplasts.

    PubMed

    Hennig, Raoul; Heidrich, Jennifer; Saur, Michael; Schmüser, Lars; Roeters, Steven J; Hellmann, Nadja; Woutersen, Sander; Bonn, Mischa; Weidner, Tobias; Markl, Jürgen; Schneider, Dirk

    2015-01-01

    The thylakoid membrane of chloroplasts and cyanobacteria is a unique internal membrane system harbouring the complexes of the photosynthetic electron transfer chain. Despite their apparent importance, little is known about the biogenesis and maintenance of thylakoid membranes. Although membrane fusion events are essential for the formation of thylakoid membranes, proteins involved in membrane fusion have yet to be identified in photosynthetic cells or organelles. Here we show that IM30, a conserved chloroplast and cyanobacterial protein of approximately 30 kDa binds as an oligomeric ring in a well-defined geometry specifically to membranes containing anionic lipids. Triggered by Mg(2+), membrane binding causes destabilization and eventually results in membrane fusion. We propose that IM30 establishes contacts between internal membrane sites and promotes fusion to enable regulated exchange of proteins and/or lipids in cyanobacteria and chloroplasts. PMID:25952141

  8. Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria.

    PubMed Central

    Garlick, S; Oren, A; Padan, E

    1977-01-01

    Eleven of 21 cyanobacteria strains examined are capable of facultative anoxygenic photosynthesis, as shown by their ability to photoassimilate CO2 in the presence of Na2S, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 703-nm light. These include different cyanobacterial types (filamentous and unicellular) of different growth histories (aerobic, anaerobic, and marine and freshwater). Oscillatoria limnetica, Aphanothece halophytica (7418), and Lyngbya (7104) have different optimal concentrations of Na2S permitting CO2 photoassimilation, above which the rate decreases: 3.5, 0.7, and 0.1 mM, respectively. In A. halophytica, for each CO2 molecule photoassimilated two sulfide molecules are oxidized to elemental sulfur, which is excreted from the cells.The ecological and evolutionary significance of anoxygenic photosynthesis in the cyanobacteria is discussed. PMID:402355

  9. Photosynthetic, respiratory and extracellular electron transport pathways in cyanobacteria.

    PubMed

    Lea-Smith, David J; Bombelli, Paolo; Vasudevan, Ravendran; Howe, Christopher J

    2016-03-01

    Cyanobacteria have evolved elaborate electron transport pathways to carry out photosynthesis and respiration, and to dissipate excess energy in order to limit cellular damage. Our understanding of the complexity of these systems and their role in allowing cyanobacteria to cope with varying environmental conditions is rapidly improving, but many questions remain. We summarize current knowledge of cyanobacterial electron transport pathways, including the possible roles of alternative pathways in photoprotection. We describe extracellular electron transport, which is as yet poorly understood. Biological photovoltaic devices, which measure electron output from cells, and which have been proposed as possible means of renewable energy generation, may be valuable tools in understanding cyanobacterial electron transfer pathways, and enhanced understanding of electron transfer may allow improvements in the efficiency of power output. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux.

  10. Allelopathic activity of the Baltic cyanobacteria against microalgae

    NASA Astrophysics Data System (ADS)

    Żak, Adam; Musiewicz, Krzysztof; Kosakowska, Alicja

    2012-10-01

    The goal of this work was to investigate the influence of Baltic cyanobacteria Anabaena variabilis and Nodularia spumigena cells and cell-free filtrates on the growth of green algae Chlorella vulgaris. We have demonstrated that Anabaena variabilis and Nodularia spumigena caused allelopathic effects against microalgae. The cyanobacterial and microalgal cultures were provided on liquid medium, in 22 °C at continuous light. Cell-free filtrates were obtained by centrifugation and filtering aliquots of cyanobacterial cultures (including cultures in exponential and stationary phase of growth). Growth response of free cells (batch culture technique) and immobilized cultures (in alginate beads) of the unicellular green algae to cyanobacteria allelochemicals were tested and compared. In this experiment Anabaena variabilis supressed the growth of microalgae compared to control samples. Nodularia spumigena stimulated the growth of Chlorella vulgaris in most cases, however both positive and negative effects were observed.

  11. Use of filamentous cyanobacteria for biodegradation of organic pollutants

    SciTech Connect

    Kuritz, T.; Wolk, C.P.

    1995-01-01

    Biodegradation is increasingly being considered as a less expensive alternative to physical and chemical means of decomposing organic pollutants. Pathways of biodegradation have been characterized for a number of heterotrophic microorganisms, mostly soil isolates, some of which have been used for remediation of water. Because cyanobacteria are photoautotrophic and some can fix atmospheric nitrogen, their use for bioremediation of surface waters would circumvent the need to supply biodegradative heterotrophs with organic nutrients. This paper demonstrates that two filamentous cyanobacteria have a natural ability to degrade a highly chlorinated aliphatic pesticide, lindane ({gamma}-hexachlorocyclohexane); presents quantitative evidence that this ability can be enhanced by genetic engineering; and provides qualitative evidence that those two strains can be genetically engineered to degrade another chlorinated pollutant, 4-chlorobenzoate. 42 refs., 3 figs.

  12. Rapid extraction of phycobiliproteins from cultured cyanobacteria samples.

    PubMed

    Viskari, Pertti J; Colyer, Christa L

    2003-08-15

    Cyanobacteria are a valuable and ubiquitous component of marine picophytoplankton that contribute significantly to total carbon biomass and primary productivity of the oceans. They contain water soluble, natively highly fluorescent proteins, phycobiliproteins, that can be considered ideal marker pigments for understanding the distribution and trophic dynamics of picoplankton populations. However, there is no standard protocol for extracting and quantitating these proteins from cyanobacterial cells. Ideally, the cells would be disrupted quickly and efficiently with complete extraction and recovery of the released proteins. For that purpose, we describe a method for extracting phycobiliproteins from a Synechococcus CCMP 833 cyanobacteria culture that utilizes 3% 3-[(3-cholamidopropyl)dimethyammonio]propanesulfonic acid (Chaps) 0.3% asolectin combined with nitrogen cavitation. Extraction efficiencies of greater than 85% were achieved by this method, which requires less than 3h. The analysis of the extracted samples was carried out by capillary electrophoresis with laser-induced fluorescence detection.

  13. Morphological and genetic diversity of symbiotic cyanobacteria from cycads.

    PubMed

    Thajuddin, Nooruddin; Muralitharan, Gangatharan; Sundaramoorthy, Mariappan; Ramamoorthy, Rengasamy; Ramachandran, Srinivasan; Akbarsha, Mohamed Abdulkadar; Gunasekaran, Muthukumaran

    2010-06-01

    The morphological and genetic diversity of cyanobacteria associated with cycads was examined using PCR amplification techniques and 16S rRNA gene sequence analysis. Eighteen symbiotic cyanobacteria were isolated from different cycad species. One of the symbiotic isolates was a species of Calothrix, a genus not previously reported to form symbioses with Cycadaceae family, and the remainder were Nostoc spp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the repetitive sequences. Based on fingerprint patterns and phenograms, it was revealed that cyanobacterial symbionts exhibit important genetic diversity among host plants, both within and between cycad populations. A phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that most of the symbiotic cyanobacterial isolates fell into well-separated clades. PMID:20473963

  14. Morphological and genetic diversity of symbiotic cyanobacteria from cycads.

    PubMed

    Thajuddin, Nooruddin; Muralitharan, Gangatharan; Sundaramoorthy, Mariappan; Ramamoorthy, Rengasamy; Ramachandran, Srinivasan; Akbarsha, Mohamed Abdulkadar; Gunasekaran, Muthukumaran

    2010-06-01

    The morphological and genetic diversity of cyanobacteria associated with cycads was examined using PCR amplification techniques and 16S rRNA gene sequence analysis. Eighteen symbiotic cyanobacteria were isolated from different cycad species. One of the symbiotic isolates was a species of Calothrix, a genus not previously reported to form symbioses with Cycadaceae family, and the remainder were Nostoc spp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the repetitive sequences. Based on fingerprint patterns and phenograms, it was revealed that cyanobacterial symbionts exhibit important genetic diversity among host plants, both within and between cycad populations. A phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that most of the symbiotic cyanobacterial isolates fell into well-separated clades.

  15. Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria.

    PubMed

    Garlick, S; Oren, A; Padan, E

    1977-02-01

    Eleven of 21 cyanobacteria strains examined are capable of facultative anoxygenic photosynthesis, as shown by their ability to photoassimilate CO2 in the presence of Na2S, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 703-nm light. These include different cyanobacterial types (filamentous and unicellular) of different growth histories (aerobic, anaerobic, and marine and freshwater). Oscillatoria limnetica, Aphanothece halophytica (7418), and Lyngbya (7104) have different optimal concentrations of Na2S permitting CO2 photoassimilation, above which the rate decreases: 3.5, 0.7, and 0.1 mM, respectively. In A. halophytica, for each CO2 molecule photoassimilated two sulfide molecules are oxidized to elemental sulfur, which is excreted from the cells. The ecological and evolutionary significance of anoxygenic photosynthesis in the cyanobacteria is discussed. PMID:402355

  16. Photosynthetic, respiratory and extracellular electron transport pathways in cyanobacteria.

    PubMed

    Lea-Smith, David J; Bombelli, Paolo; Vasudevan, Ravendran; Howe, Christopher J

    2016-03-01

    Cyanobacteria have evolved elaborate electron transport pathways to carry out photosynthesis and respiration, and to dissipate excess energy in order to limit cellular damage. Our understanding of the complexity of these systems and their role in allowing cyanobacteria to cope with varying environmental conditions is rapidly improving, but many questions remain. We summarize current knowledge of cyanobacterial electron transport pathways, including the possible roles of alternative pathways in photoprotection. We describe extracellular electron transport, which is as yet poorly understood. Biological photovoltaic devices, which measure electron output from cells, and which have been proposed as possible means of renewable energy generation, may be valuable tools in understanding cyanobacterial electron transfer pathways, and enhanced understanding of electron transfer may allow improvements in the efficiency of power output. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux. PMID:26498190

  17. Siderophilic Cyanobacteria for the Development of Extraterrestrial Photoautotrophic Biotechnologies

    NASA Technical Reports Server (NTRS)

    Brown, I. I.; McKay, D. S.

    2010-01-01

    In-situ production of consumables (mainly oxygen) using local resources (In-Situ Resource Utilization-ISRU) will significantly facilitate current plans for human exploration and settlement of the solar system, starting with the Moon. With few exceptions, nearly all technologies developed to date have employed an approach based on inorganic chemistry. None of these technologies include concepts for integrating the ISRU system with a bioregenerative life support system and a food production system. Therefore, a new concept based on the cultivation of cyanobacteria (CB) in semi-closed biogeoreactor, linking ISRU, a biological life support system, and food production, has been proposed. The key feature of the biogeoreactor is to use lithotrophic CB to extract many needed elements such as Fe directly from the dissolved regolith and direct them to any technological loop at an extraterrestrial outpost. Our studies showed that siderophilic (Fe-loving) CB are capable to corrode lunar regolith stimulants because they secrete chelating agents and can tolerate [Fe] up to 1 mM. However, lunar and Martian environments are very hostile (very high UV and gamma-radiation, extreme temperatures, deficit of water). Thus, the selection of CB species with high potential for extraterrestrial biotechnologies that may be utilized in 15 years must be sponsored by NASA as soon as possible. The study of the genomes of candidate CB species and the metagenomes of the terrestrial environments which they inhabit is critical to make this decision. Here we provide preliminary results about peculiarities of the genomes of siderophilic CB revealed by analyzing the genome of siderophilic cyanobacterium JSC-1 and the metagenome of iron depositing hot spring (IDHS) Chocolate Pots (Yellowstone National Park, Wyoming, USA). It has been found that IDHS are richer with ferrous iron than the majority of hot springs around the world. Fe2+ is known to increase the magnitude of oxidative stress in prokaryotes

  18. Geographical modeling of exposure risk to cyanobacteria for epidemiological purposes.

    PubMed

    Serrano, Tania; Dupas, Rémi; Upegui, Erika; Buscail, Camille; Grimaldi, Catherine; Viel, Jean François

    2015-08-01

    The cyanobacteria-derived neurotoxin β-methylamino-L-alanine (BMAA) represents a plausible environmental trigger for amyotrophic lateral sclerosis (ALS), a debilitating and fatal neuromuscular disease. With the eutrophication of water bodies, cyanobacterial blooms and their toxins are becoming increasingly prevalent in France, especially in the Brittany region. Cyanobacteria are monitored at only a few recreational sites, preventing an estimation of exposure of the human population. By contrast, phosphorus, a limiting nutrient for cyanobacterial growth and thus considered a good proxy for cyanobacteria exposure, is monitored in many but not all surface water bodies. Our goal was to develop a geographic exposure indicator that could be used in epidemiological research. We considered the total phosphorus (TP) concentration (mg/L) of samples collected between October 2007 and September 2012 at 179 monitoring stations distributed throughout the Brittany region. Using readily available spatial data, we computed environmental descriptors at the watershed level with a Geographic Information System. Then, these descriptors were introduced into a backward stepwise linear regression model to predict the median TP concentration in unmonitored surface water bodies. TP concentrations in surface water follow an increasing gradient from West to East and inland to coast. The empirical concentration model included five predictor variables with a fair coefficient of determination (R(2) = 0.51). The specific total runoff and the watershed slope correlated negatively with the TP concentrations (p = 0.01 and p< 10(-9), respectively), whereas positive associations were found for the proportion of built-up area, the upstream presence of sewage treatment plants, and the algae volume as indicated by the Landsat red/green reflectance ratio (p < 0.01, p < 10(-6) and p < 0.01, respectively). Complementing the monitoring networks, this geographical modeling can help estimate TP concentrations

  19. Reassessing the first appearance of eukaryotes and cyanobacteria.

    PubMed

    Rasmussen, Birger; Fletcher, Ian R; Brocks, Jochen J; Kilburn, Matt R

    2008-10-23

    The evolution of oxygenic photosynthesis had a profound impact on the Earth's surface chemistry, leading to a sharp rise in atmospheric oxygen between 2.45 and 2.32 billion years (Gyr) ago and the onset of extreme ice ages. The oldest widely accepted evidence for oxygenic photosynthesis has come from hydrocarbons extracted from approximately 2.7-Gyr-old shales in the Pilbara Craton, Australia, which contain traces of biomarkers (molecular fossils) indicative of eukaryotes and suggestive of oxygen-producing cyanobacteria. The soluble hydrocarbons were interpreted to be indigenous and syngenetic despite metamorphic alteration and extreme enrichment (10-20 per thousand) of (13)C relative to bulk sedimentary organic matter. Here we present micrometre-scale, in situ (13)C/(12)C measurements of pyrobitumen (thermally altered petroleum) and kerogen from these metamorphosed shales, including samples that originally yielded biomarkers. Our results show that both kerogen and pyrobitumen are strongly depleted in (13)C, indicating that indigenous petroleum is 10-20 per thousand lighter than the extracted hydrocarbons. These results are inconsistent with an indigenous origin for the biomarkers. Whatever their origin, the biomarkers must have entered the rock after peak metamorphism approximately 2.2 Gyr ago and thus do not provide evidence for the existence of eukaryotes and cyanobacteria in the Archaean eon. The oldest fossil evidence for eukaryotes and cyanobacteria therefore reverts to 1.78-1.68 Gyr ago and approximately 2.15 Gyr ago, respectively. Our results eliminate the evidence for oxygenic photosynthesis approximately 2.7 Gyr ago and exclude previous biomarker evidence for a long delay (approximately 300 million years) between the appearance of oxygen-producing cyanobacteria and the rise in atmospheric oxygen 2.45-2.32 Gyr ago. PMID:18948954

  20. Reassessing the first appearance of eukaryotes and cyanobacteria.

    PubMed

    Rasmussen, Birger; Fletcher, Ian R; Brocks, Jochen J; Kilburn, Matt R

    2008-10-23

    The evolution of oxygenic photosynthesis had a profound impact on the Earth's surface chemistry, leading to a sharp rise in atmospheric oxygen between 2.45 and 2.32 billion years (Gyr) ago and the onset of extreme ice ages. The oldest widely accepted evidence for oxygenic photosynthesis has come from hydrocarbons extracted from approximately 2.7-Gyr-old shales in the Pilbara Craton, Australia, which contain traces of biomarkers (molecular fossils) indicative of eukaryotes and suggestive of oxygen-producing cyanobacteria. The soluble hydrocarbons were interpreted to be indigenous and syngenetic despite metamorphic alteration and extreme enrichment (10-20 per thousand) of (13)C relative to bulk sedimentary organic matter. Here we present micrometre-scale, in situ (13)C/(12)C measurements of pyrobitumen (thermally altered petroleum) and kerogen from these metamorphosed shales, including samples that originally yielded biomarkers. Our results show that both kerogen and pyrobitumen are strongly depleted in (13)C, indicating that indigenous petroleum is 10-20 per thousand lighter than the extracted hydrocarbons. These results are inconsistent with an indigenous origin for the biomarkers. Whatever their origin, the biomarkers must have entered the rock after peak metamorphism approximately 2.2 Gyr ago and thus do not provide evidence for the existence of eukaryotes and cyanobacteria in the Archaean eon. The oldest fossil evidence for eukaryotes and cyanobacteria therefore reverts to 1.78-1.68 Gyr ago and approximately 2.15 Gyr ago, respectively. Our results eliminate the evidence for oxygenic photosynthesis approximately 2.7 Gyr ago and exclude previous biomarker evidence for a long delay (approximately 300 million years) between the appearance of oxygen-producing cyanobacteria and the rise in atmospheric oxygen 2.45-2.32 Gyr ago.

  1. Blooms of Cyanobacteria on the Potomac River 1

    PubMed Central

    Krogmann, David W.; Butalla, Ruth; Sprinkle, James

    1986-01-01

    Blooms of cyanobacteria have appeared on the Potomac River near Washington, DC in years of drought and low river volume. The location of the bloom may be related to tidal activity. In 1983, the bloom of Microcystis aeruginosa used ammonia as its nitrogen source and contained low levels of toxic peptides. Cells collected from this bloom proved to be homogeneous and were an excellent source material for the isolation of proteins involved in photosynthesis. PMID:16664682

  2. Solar Ultraviolet and the Evolutionary History of Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Garcia-Pichel, F.

    1998-06-01

    On the basis of photobiological, evolutionary, paleontological, paleoenvironmental and physiological arguments, a time course for the role of solar ultraviolet radiation (UVR, wavelengths below 400 nm) in the ecology and evolution of cyanobacteria is proposed in which three main periods can be distinguished. An initial stage, before the advent of oxygenic photosynthesis, when high environmental fluxes of UVC (wavelengths below 280 nm) and UVB (280-320 nm) may have depressed the ability of protocyanobacteria to develop large populations or restricted them to UVR refuges. A second stage lasting between 500 and 1500 Ma (million years), started with the appearance of true oxygen-evolving cyanobacteria and the concomitant formation of oxygenated (micro)environments under an oxygen free-atmosphere. In this second stage, the age of UV, the overall importance of UVR must have increased substantially, since the incident fluxes of UVC and UVB remained virtually unchanged, but additionally the UVA portion of the spectrum (320-400 nm) suddenly became biologically injurious and extremely reactive oxygen species must have formed wherever oxygen and UVR spatially coincided. The last period began with the gradual oxygenation of the atmosphere and the formation of the stratospheric ozone shield. The physiological stress due to UVC all but disappeared and the effects of UVB were reduced to a large extent. Evidence in support of this dynamics is drawn from the phylogenetic distribution of biochemical UV-defense mechanisms among cyanobacteria and other microorganisms. The specific physical characteristics of UVR and oxygen exposure in planktonic, sedimentary and terrestrial habitats are used to explore the plausible impact of UVR in each of the periods on the ecological distribution of cyanobacteria.

  3. Extracellular Proteins: Novel Key Components of Metal Resistance in Cyanobacteria?

    PubMed Central

    Giner-Lamia, Joaquín; Pereira, Sara B.; Bovea-Marco, Miquel; Futschik, Matthias E.; Tamagnini, Paula; Oliveira, Paulo

    2016-01-01

    Metals are essential for all living organisms and required for fundamental biochemical processes. However, when in excess, metals can turn into highly-toxic agents able to disrupt cell membranes, alter enzymatic activities, and damage DNA. Metal concentrations are therefore tightly controlled inside cells, particularly in cyanobacteria. Cyanobacteria are ecologically relevant prokaryotes that perform oxygenic photosynthesis and can be found in many different marine and freshwater ecosystems, including environments contaminated with heavy metals. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been widely studied in cyanobacteria. So far, most studies have focused on how cells are capable of controlling their internal metal pools, with a strong bias toward the analysis of intracellular processes. Ultrastructure, modulation of physiology, dynamic changes in transcription and protein levels have been studied, but what takes place in the extracellular environment when cells are exposed to an unbalanced metal availability remains largely unknown. The interest in studying the subset of proteins present in the extracellular space has only recently begun and the identification and functional analysis of the cyanobacterial exoproteomes are just emerging. Remarkably, metal-related proteins such as the copper-chaperone CopM or the iron-binding protein FutA2 have already been identified outside the cell. With this perspective, we aim to raise the awareness that metal-resistance mechanisms are not yet fully known and hope to motivate future studies assessing the role of extracellular proteins on bacterial metal homeostasis, with a special focus on cyanobacteria. PMID:27375598

  4. TonB-dependent transporters and their occurrence in cyanobacteria

    PubMed Central

    Mirus, Oliver; Strauss, Sascha; Nicolaisen, Kerstin; von Haeseler, Arndt; Schleiff, Enrico

    2009-01-01

    Background Different iron transport systems evolved in Gram-negative bacteria during evolution. Most of the transport systems depend on outer membrane localized TonB-dependent transporters (TBDTs), a periplasma-facing TonB protein and a plasma membrane localized machinery (ExbBD). So far, iron chelators (siderophores), oligosaccharides and polypeptides have been identified as substrates of TBDTs. For iron transport, three uptake systems are defined: the lactoferrin/transferrin binding proteins, the porphyrin-dependent transporters and the siderophore-dependent transporters. However, for cyanobacteria almost nothing is known about possible TonB-dependent uptake systems for iron or other substrates. Results We have screened all publicly available eubacterial genomes for sequences representing (putative) TBDTs. Based on sequence similarity, we identified 195 clusters, where elements of one cluster may possibly recognize similar substrates. For Anabaena sp. PCC 7120 we identified 22 genes as putative TBDTs covering almost all known TBDT subclasses. This is a high number of TBDTs compared to other cyanobacteria. The expression of the 22 putative TBDTs individually depends on the presence of iron, copper or nitrogen. Conclusion We exemplified on TBDTs the power of CLANS-based classification, which demonstrates its importance for future application in systems biology. In addition, the tentative substrate assignment based on characterized proteins will stimulate the research of TBDTs in different species. For cyanobacteria, the atypical dependence of TBDT gene expression on different nutrition points to a yet unknown regulatory mechanism. In addition, we were able to clarify a hypothesis of the absence of TonB in cyanobacteria by the identification of according sequences. PMID:19821963

  5. Decline in water level boosts cyanobacteria dominance in subtropical reservoirs.

    PubMed

    Yang, Jun; Lv, Hong; Yang, Jun; Liu, Lemian; Yu, Xiaoqing; Chen, Huihuang

    2016-07-01

    Globally aquatic ecosystems are likely to become more vulnerable to extreme water fluctuation rates due to the combined effects of climate change and human activity. However, relatively little is known about the importance of water level fluctuations (WLF) as a predictor of phytoplankton community shifts in subtropical reservoirs. In this study, we used one year of data (2010-2011) from four subtropical reservoirs of southeast China to quantify the effects of WLF and other environmental variables on phytoplankton and cyanobacteria dynamics. The reservoirs showed an apparent switch between a turbid state dominated by cyanobacteria and a clear state dominated by other non-cyanobacterial taxa (e.g., diatoms, green algae). Cyanobacterial dominance decreased, or increased, following marked changes in water level. Multiple regression analysis demonstrated that pH, euphotic depth, WLF, and total phosphorus provided the best model and explained 30.8% of the variance in cyanobacteria biomass. Path analysis showed that positive WLF (i.e. an increase in water level) can reduce the cyanobacteria biomass either directly by a dilution effect or indirectly by modifying the limnological conditions of the reservoirs in complex pathways. To control the risk of cyanobacterial dominance or blooms, WLF should be targeted to be above +2m/month; that is an increase in water level of 2m or more. Given that WLF is likely to be of more frequent occurrence under future predicted conditions of climate variability and human activity, water level management can be widely used in small and medium-sized reservoirs to prevent the toxic cyanobacterial blooms and to protect the ecosystem integrity or functions. PMID:27016690

  6. Comparison of cyanobacterial microcystin synthetase (mcy) E gene transcript levels, mcy E gene copies, and biomass as indicators of microcystin risk under laboratory and field conditions

    PubMed Central

    Ngwa, Felexce F; Madramootoo, Chandra A; Jabaji, Suha

    2014-01-01

    Increased incidences of mixed assemblages of microcystin-producing and nonproducing cyanobacterial strains in freshwater bodies necessitate development of reliable proxies for cyanotoxin risk assessment. Detection of microcystin biosynthetic genes in water blooms of cyanobacteria is generally indicative of the presence of potentially toxic cyanobacterial strains. Although much effort has been devoted toward elucidating the microcystin biosynthesis mechanisms in many cyanobacteria genera, little is known about the impacts of co-occurring cyanobacteria on cellular growth, mcy gene expression, or mcy gene copy distribution. The present study utilized conventional microscopy, qPCR assays, and enzyme-linked immunosorbent assay to study how competition between microcystin-producing Microcystis aeruginosa CPCC 299 and Planktothrix agardhii NIVA-CYA 126 impacts mcyE gene expression, mcyE gene copies, and microcystin concentration under controlled laboratory conditions. Furthermore, analyses of environmental water samples from the Missisquoi Bay, Quebec, enabled us to determine how the various potential toxigenic cyanobacterial biomass proxies correlated with cellular microcystin concentrations in a freshwater lake. Results from our laboratory study indicated significant downregulation of mcyE gene expression in mixed cultures of M. aeruginosa plus P. agardhii on most sampling days in agreement with depressed growth recorded in the mixed cultures, suggesting that interaction between the two species probably resulted in suppressed growth and mcyE gene expression in the mixed cultures. Furthermore, although mcyE gene copies and McyE transcripts were detected in all laboratory and field samples with measureable microcystin levels, only mcyE gene copies showed significant positive correlations (R2 > 0.7) with microcystin concentrations, while McyE transcript levels did not. These results suggest that mcyE gene copies are better indicators of potential risks from microcystins

  7. Light-dependent governance of cell shape dimensions in cyanobacteria

    PubMed Central

    Montgomery, Beronda L.

    2015-01-01

    The regulation of cellular dimension is important for the function and survival of cells. Cellular dimensions, such as size and shape, are regulated throughout the life cycle of bacteria and can be adapted in response to environmental changes to fine-tune cellular fitness. Cell size and shape are generally coordinated with cell growth and division. Cytoskeletal regulation of cell shape and cell wall biosynthesis and/or deposition occurs in a range of organisms. Photosynthetic organisms, such as cyanobacteria, particularly exhibit light-dependent regulation of morphogenes and generation of reactive oxygen species and other signals that can impact cellular dimensions. Environmental signals initiate adjustments of cellular dimensions, which may be vitally important for optimizing resource acquisition and utilization or for coupling the cellular dimensions with the regulation of subcellular organization to maintain optimal metabolism. Although the involvement of cytoskeletal components in the regulation of cell shape is widely accepted, the signaling factors that regulate cytoskeletal and other distinct components involved in cell shape control, particularly in response to changes in external light cues, remain to be fully elucidated. In this review, factors impacting the inter-coordination of growth and division, the relationship between the regulation of cellular dimensions and central carbon metabolism, and consideration of the effects of specific environment signals, primarily light, on cell dimensions in cyanobacteria will be discussed. Current knowledge about the molecular bases of the light-dependent regulation of cellular dimensions and cell shape in cyanobacteria will be highlighted. PMID:26074902

  8. Motility in cyanobacteria: polysaccharide tracks and Type IV pilus motors.

    PubMed

    Wilde, Annegret; Mullineaux, Conrad W

    2015-12-01

    Motility in cyanobacteria is useful for purposes that range from seeking out favourable light environments to establishing symbioses with plants and fungi. No known cyanobacterium is equipped with flagella, but a diverse range of species is able to 'glide' or 'twitch' across surfaces. Cyanobacteria with this capacity range from unicellular species to complex filamentous forms, including species such as Nostoc punctiforme, which can generate specialised motile filaments called hormogonia. Recent work on the model unicellular cyanobacterium Synechocystis sp. PCC 6803 has shown that its means of propulsion has much in common with the twitching motility of heterotrophs such as Pseudomonas and Myxococcus. Movement depends on Type IV pili, which are extended, adhere to the substrate and then retract to pull the cell across the surface. Previous work on filamentous cyanobacteria suggested a very different mechanism, with movement powered by the directional extrusion of polysaccharide from pores close to the cell junctions. Now a new report by Khayatan and colleagues in this issue of Molecular Microbiology suggests that the motility of Nostoc hormogonia has much more in common with Synechocystis than was previously thought. In both cases, polysaccharide secretion is important for preparing the surface, but the directional motive force comes from Type IV pili.

  9. Motility in cyanobacteria: polysaccharide tracks and Type IV pilus motors.

    PubMed

    Wilde, Annegret; Mullineaux, Conrad W

    2015-12-01

    Motility in cyanobacteria is useful for purposes that range from seeking out favourable light environments to establishing symbioses with plants and fungi. No known cyanobacterium is equipped with flagella, but a diverse range of species is able to 'glide' or 'twitch' across surfaces. Cyanobacteria with this capacity range from unicellular species to complex filamentous forms, including species such as Nostoc punctiforme, which can generate specialised motile filaments called hormogonia. Recent work on the model unicellular cyanobacterium Synechocystis sp. PCC 6803 has shown that its means of propulsion has much in common with the twitching motility of heterotrophs such as Pseudomonas and Myxococcus. Movement depends on Type IV pili, which are extended, adhere to the substrate and then retract to pull the cell across the surface. Previous work on filamentous cyanobacteria suggested a very different mechanism, with movement powered by the directional extrusion of polysaccharide from pores close to the cell junctions. Now a new report by Khayatan and colleagues in this issue of Molecular Microbiology suggests that the motility of Nostoc hormogonia has much more in common with Synechocystis than was previously thought. In both cases, polysaccharide secretion is important for preparing the surface, but the directional motive force comes from Type IV pili. PMID:26447922

  10. Biochemical changes in cyanobacteria during the synthesis of silver nanoparticles.

    PubMed

    Cepoi, L; Rudi, L; Chiriac, T; Valuta, A; Zinicovscaia, I; Duca, Gh; Kirkesali, E; Frontasyeva, M; Culicov, O; Pavlov, S; Bobrikov, I

    2015-01-01

    The methods of synthesis of silver (Ag) nanoparticles by the cyanobacteria Spirulina platensis and Nostoc linckia were studied. A complex of biochemical, spectral, and analytical methods was used to characterize biomass and to assess changes in the main components of biomass (proteins, lipids, carbohydrates, and phycobilin) during nanoparticle formation. The size and shape of Ag nanoparticles in the biomass of both types of cyanobacteria were determined. Neutron activation analysis was used to study the accumulation dynamics of the Ag quantity. The analytical results suggest that the major reduction of Ag concentration in solutions and the increase in biomass occur within the first 24 h of experiments. While in this time interval minor changes in the N. linckia and S. platensis biomass took place, a significant reduction of the levels of proteins, carbohydrates, and phycobiliproteins in both cultures and of lipids in S. platensis was observed after 48 h. At the same time, the antiradical activity of the biomass decreased. The obtained results show the necessity of determining the optimal conditions of the interaction between the biomass and the solution containing Ag ions that would allow nanoparticle formation without biomass degradation at the time of Ag nanoparticle formation by the studied cyanobacteria. PMID:25444587

  11. A review on possible elicitor molecules of cyanobacteria: their role in improving plant growth and providing tolerance against biotic or abiotic stress.

    PubMed

    Singh, S

    2014-11-01

    Cyanobacteria are prominent inhabitants of many agricultural soils, where they potentially contribute towards biological nitrogen fixation, help in phosphate solubilization and mineral release to improve soil fertility and crop productivity. However, beside naturally fertilizing and balancing mineral nutrition in the soil, many cyanobacteria are known to release various kinds of biologically active substances like proteins, vitamins, carbohydrates, amino acids, polysaccharides and phytohormones that function as elicitor molecules to promote plant growth and help them to fight against biotic and abiotic stress. These metabolites produced by the cyanobacteria affect the gene expression of the host plants and thereby bring about qualitative and quantitative changes in the phytochemical composition of the plants. Experiments carried out with live inoculum or with the extracts of cyanobacterial strains on several plant species, such as rice, wheat, maize, cotton etc., have demonstrated the synthesis of signalling metabolites. Thus, in view of its beneficial effect, this paper reviews the role of cyanobacteria in triggering the growth and development of plants and hence its utilization in agriculture.

  12. A simple recovery process for biodegradable plastics accumulated in cyanobacteria treated with ionic liquids.

    PubMed

    Kobayashi, Daigo; Fujita, Kyoko; Nakamura, Nobuhumi; Ohno, Hiroyuki

    2015-02-01

    Here, we proposed a simple recovery process for poly(3-hydroxybutyrate) (PHB) accumulated in cyanobacteria by using ionic liquids (ILs), which dissolve cyanobacteria but not PHB. First, we investigated the effects of IL polarity on hydrogen-bonding receipt ability (β value) and hydrogen-bonding donating ability (α value) and evaluated the subsequent dissolution of cyanobacteria. We found that ILs having α values higher than approximately 0.4 and β values of approximately 0.9 were suitable for dissolution of cyanobacteria. In particular, 1-ethyl-3-methylimidazolium methylphosphonate ([C2mim][MeO(H)PO2]) was found to dissolve cyanobacteria components, but not PHB. Thus, we verified that PHB produced in cyanobacteria could be separated and recovered by simple filtering after dissolution of cyanobacteria in [C2mim][MeO(H)PO2]. Using this technique, more than 98 % of PHB was obtained on the filter as residues separated from cyanobacteria. Furthermore, [C2mim][MeO(H)PO2] maintained the ability to dissolve cyanobacteria after a simple recycling procedure.

  13. Cyanobacteria associated with Anopheles albimanus (Diptera: Culicidae) larval habitats in southern Mexico.

    PubMed

    Vázquez-Martínez, M Guadalupe; Rodríguez, Mario H; Arredondo-Jiménez, Juan I; Méndez-Sanchez, José D; Bond-Compeán, J Guillermo; Cold-Morgan, Michelle

    2002-11-01

    Cyanobacteria associated with Anopheles albimanus Wiedemann larval habitats from southern Chiapas, Mexico, were isolated and identified from water samples and larval midguts using selective medium BG-11. Larval breeding sites were classified according to their hydrology and dominant vegetation. Cyanobacteria isolated in water samples were recorded and analyzed according to hydrological and vegetation habitat breeding types, and mosquito larval abundance. In total, 19 cyanobacteria species were isolated from water samples. Overall, the most frequently isolated cyanobacterial taxa were Phormidium sp., Oscillatoria sp., Aphanocapsa cf. littoralis, Lyngbya lutea, P. animalis, and Anabaena cf. spiroides. Cyanobacteria were especially abundant in estuaries, irrigation canals, river margins and mangrove lagoons, and more cyanobacteria were isolated from Brachiaria mutica, Ceratophyllum demersum, and Hymenachne amplexicaulis habitats. Cyanobacteria were found in habitats with low to high An. albimanus larval abundance, but Aphanocapsa cf. littoralis was associated with habitats of low larval abundance. No correlation was found between water chemistry parameters and the presence of cyanobacteria, however, water temperature (29.2-29.4 degrees C) and phosphate concentration (79.8-136.5 ppb) were associated with medium and high mosquito larvae abundance. In An. albimanus larval midguts, only six species of cyanobacteria were isolated, the majority being from the most abundant cyanobacteria in water samples.

  14. Understanding Sugar Catabolism in Unicellular Cyanobacteria Toward the Application in Biofuel and Biomaterial Production.

    PubMed

    Osanai, Takashi; Iijima, Hiroko; Hirai, Masami Yokota

    2016-01-01

    Synechocystis sp. PCC 6803 is a model species of the cyanobacteria that undergo oxygenic photosynthesis, and has garnered much attention for its potential biotechnological applications. The regulatory mechanism of sugar metabolism in this cyanobacterium has been intensively studied and recent omics approaches have revealed the changes in transcripts, proteins, and metabolites of sugar catabolism under different light and nutrient conditions. Several transcriptional regulators that control the gene expression of enzymes related to sugar catabolism have been identified in the past 10 years, including a sigma factor, transcription factors, and histidine kinases. The modification of these genes can lead to alterations in the primary metabolism as well as the levels of high-value products such as bioplastics and hydrogen. This review summarizes recent studies on sugar catabolism in Synechocystis sp. PCC 6803, emphasizing the importance of elucidating the molecular mechanisms of cyanobacterial metabolism for biotechnological applications. PMID:27023248

  15. Targeted Natural Products Discovery from Marine Cyanobacteria Using Combined Phylogenetic and Mass Spectrometric Evaluation

    PubMed Central

    Salvador-Reyes, Lilibeth A.; Engene, Niclas; Paul, Valerie J.; Luesch, Hendrik

    2016-01-01

    Combined phylogenetic and HPLC-MS-based natural products dereplication methods aimed at identifying cyanobacterial collections containing the potent cytotoxins largazole, dolastatin 10 and symplostatin 1 were developed. The profiling of the phylogeny, chemical space, and antiproliferative activity of cyanobacterial collections served to streamline the prioritization of samples for the discovery of new secondary metabolites. The dereplication methods highlighted the biosynthetic potential and combinatorial pharmacology employed by marine cyanobacteria. We found that largazole was always coproduced with dolastatin 10 or with symplostatin 1 and consequently tested combinations of these agents against colon cancer cells. Combinatorial regimens of largazole and dolastatin 10 aimed at curbing the growth of HCT116 cancer cells showed cooperative activity. PMID:25635943

  16. Endocrine, teratogenic and neurotoxic effects of cyanobacteria detected by cellular in vitro and zebrafish embryos assays.

    PubMed

    Jonas, Adam; Scholz, Stefan; Fetter, Eva; Sychrova, Eliska; Novakova, Katerina; Ortmann, Julia; Benisek, Martin; Adamovsky, Ondrej; Giesy, John P; Hilscherova, Klara

    2015-02-01

    Cyanobacteria contain various types of bioactive compounds, which could cause adverse effects on organisms. They are released into surface waters during cyanobacterial blooms, but there is little information on their potential relevance for effects in vivo. In this study presence of bioactive compounds was characterized in cyanobacteria Microcystis aeruginosa (Chroococcales), Planktothrix agardhii (Oscillatoriales) and Aphanizomenon gracile (Nostocales) with selected in vitro assays. The in vivo relevance of detected bioactivities was analysed using transgenic zebrafish embryos tg(cyp19a1b-GFP). Teratogenic potency was assessed by analysis of developmental disorders and effects on functions of the neuromuscular system by video tracking of locomotion. Estrogenicity in vitro corresponded to 0.95-54.6 ng estradiol equivalent(g dry weight (dw))(-1). In zebrafish embryos, estrogenic effects could not be detected potentially because they were masked by high toxicity. There was no detectable (anti)androgenic/glucocorticoid activity in any sample. Retinoid-like activity was determined at 1-1.3 μg all-trans-retinoic acid equivalent(g dw)(-1). Corresponding to the retinoid-like activity A. gracile extract also caused teratogenic effects in zebrafish embryos. Furthermore, exposure to biomass extracts at 0.3 gd wL(-1) caused increase of body length in embryos. There were minor effects on locomotion caused by 0.3 gd wL(-1)M. aeruginosa and P. agardhii extracts. The traditionally measured cyanotoxins microcystins did not seem to play significant role in observed effects. This indicates importance of other cyanobacterial compounds at least towards some species or their developmental phases. More attention should be paid to activity of retinoids, estrogens and other bioactive substances in phytoplankton using in vitro and in vivo bioassays. PMID:25170595

  17. Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites

    NASA Astrophysics Data System (ADS)

    Hoover, Richard B.

    2005-09-01

    The quest for conclusive evidence of microfossils in meteorites has been elusive. Abiotic microstructures, mineral grains, and even coating artifacts may mimic unicellular bacteria, archaea and nanobacteria with simple spherical or rod morphologies (i.e., cocci, diplococci, bacilli, etc.). This is not the case for the larger and more complex microorganisms, colonies and microbial consortia and ecosystems. Microfossils of algae, cyanobacteria, and cyanobacterial and microbial mats have been recognized and described from many of the most ancient rocks on Earth. The filamentous cyanobacteria and sulphur-bacteria have very distinctive size ranges, complex and recognizable morphologies and visibly differentiated cellular microstructures. The taphonomic modes of fossilization and the life habits and processes of these microorganisms often result in distinctive chemical biosignatures associated with carbonization, silicification, calcification, phosphatization and metal-binding properties of their cell-walls, trichomes, sheaths and extracellular polymeric substances (EPS). Valid biogenicity is provided by the combination of a suite of known biogenic elements (that differ from the meteorite matrix) found in direct association with recognizable and distinct biological features and microstructures (e.g., uniseriate or multiseriate filaments, trichomes, sheaths and cells of proper size/size range); specialized cells (e.g., basal or apical cells, hormogonia, akinetes, and heterocysts); and evidence of growth characteristics (e.g., spiral filaments, robust or thin sheaths, laminated sheaths, true or false branching of trichomes, tapered or uniform filaments) and evidence of locomotion (e.g. emergent cells and trichomes, coiling hormogonia, and hollow or flattened and twisted sheaths). Since 1997 we have conducted Environmental and Field Emission Scanning Electron Microscopy (ESEM and FESEM) studies of freshly fractured interior surfaces of carbonaceous meteorites, terrestrial

  18. Improved production of fatty alcohols in cyanobacteria by metabolic engineering

    PubMed Central

    2014-01-01

    Background Fatty alcohols are widely used in industrial chemicals. The biosynthetic pathways for fatty alcohols are diverse and widely existing in nature. They display a high capacity to produce fatty alcohols by the metabolic engineering of different microbe hosts. Direct recycling of carbon dioxide to fatty alcohols can be achieved by introducing a fatty alcohol-producing pathway into photosynthetic cyanobacteria. According to our precious reports, a relatively low yield of fatty alcohols was obtained in the genetically engineered cyanobacterium Synechocystis sp. PCC 6803. Results The photosynthetic production of fatty alcohols in Synechocystis sp. PCC 6803 was improved through heterologously expressing fatty acyl-Coenzyme A (acyl-CoA) reductase gene maqu_2220 from the marine bacterium Marinobacter aquaeolei VT8. Maqu_2220 has been proved to catalyze both the four-electron reduction of fatty acyl-CoA or acyl-Acyl Carrier Protein (acyl-ACP) and the two-electron reduction of fatty aldehyde to fatty alcohol. The knockout of the aldehyde-deformylating oxygenase gene (sll0208) efficiently blocked the hydrocarbon accumulation and redirected the carbon flux into the fatty alcohol-producing pathway. By knocking-out both sll0208 and sll0209 (encoding an acyl-ACP reductase), the productivity of fatty alcohols was further increased to 2.87 mg/g dry weight. Conclusions The highest yield of fatty alcohols was achieved in cyanobacteria by expressing the prokaryotic fatty acyl-CoA reductase Maqu_2220 and knocking-out the two key genes (sll0208 and sll0209) that are involved in the alka(e)ne biosynthesis pathway. Maqu_2220 was demonstrated as a robust enzyme for producing fatty alcohols in cyanobacteria. The production of fatty alcohols could be significantly increased by blocking the hydrocarbon biosynthesis pathway. PMID:25024742

  19. The Role of Cyanobacteria Blooms in Cholera Epidemic in Bangladesh

    NASA Astrophysics Data System (ADS)

    Sagir Ahmed, Md.; Raknuzzaman, Md.; Akther, Hafeza; Ahmed, Sumaiya

    A study was conducted on association of Vibrio cholerae with plankton specially emphasis on cyanobacteria in relation to some physico-chemical parameters in the River Buriganga, Dhaka, from January to December 2002. Monthly abundance of phytoplankton and zooplankton varied from 457 to 14166 and from 169 to 1055 individual L-1, respectively. Monthly average of faecal coliform in water, zooplankton and phytoplankton samples were 3.99x109, 4.54x103 and 4.28x102 (CFU L-1), respectively. During epidemics, toxigenic V. cholerae 01 and 0139 were isolated from the patients as well as from the surface water. V. cholerae 01 and 0139 were also isolated from plankton samples. More over, it was observed that ctx (cholera toxic) positive in water and phytoplankton samples of the river. A bloom of Oscillatoria sp. (1.6x104 individual L-1) occurred in the upper reaches of the River Buriganga in May 2002. Methanol-water extract of bloom sample was analyzed by high performance liquid chromatography with UV detection and Mass Spectrum (MS) detected microcystin-RR. Cyanobacteria are abundant in the aquatic environment of Bangladesh and it was established that V. cholerae maintain a symbiotic relationship with these algae particularly mucilaginous cyanobacteria. During epidemics, patients symptoms included diarrhea, vomiting and hemorrhagic enteritis and in severe cases hemorrhagic diarrhea. So, question has arisen that which is responsible, microcystins or cholera for death of cholera/diarrhea patients in Bangladesh. Future research should be directed to isolate microcystins and cholera toxins from the epidemic areas to clarify the fact.

  20. Can we expect habitable niches for cyanobacteria on Mars?

    NASA Astrophysics Data System (ADS)

    de Vera, Jean-Pierre Paul; Lorek, Andreas; Koncz, Alexander; Billi, Daniela; Baqué, Mickael; Leya, Thomas; Brown, Sarah; Cockell, Charles

    2013-04-01

    The most resistant cyanobacteria can be found in tropic deserts and in polar and alpine habitats. The reason for their resistance can be explained by their occurrence in intensely irradiated, very dry and/or cold environments which are supposed to be as close as possible similar to Martian surface conditions. A systematically approach comparing measurements on photosynthetic activity of cyanobacteria in relation to measured environmental parameters obtained in Mars analog field sites with data collected from space exposed samples or during Mars simulation experiments will show differences and common results after analyzing the investigated organisms. Some of the investigated species are foreseen to be exposed during the next ESA-space-exposure experiment BIOMEX either directly to real space conditions on space exposure platforms like EXPOSE-R2 on the International Space Station or to Mars simulation conditions in a Mars simulation chamber. Some of the species were still exposed to both of the extreme environmental conditions and some of the results will be presented and might serve for future investigations as references. We will emphasize that in parallel monitoring of environmental parameters on Mars analog field sites was performed as well as partly in space and in the simulation chambers. This experimental combination might help to get a better impression about the influence of each of the tested parameters on metabolic activity of the tested cyanobacteria in complete different planetary environments comparing characterized habitats on our home planet Earth with those we might expect according to recently observed data on Mars. The outcome of this work could be relevant to classify e.g. Mars as a habitable planet by a new combination of different experimental and biological approaches and to evaluate and discuss the likelihood of terra forming Mars in the far future.

  1. Biotransformation and Volatilization of Arsenic by Three Photosynthetic Cyanobacteria1

    PubMed Central

    Yin, Xi-Xiang; Chen, Jian; Qin, Jie; Sun, Guo-Xin; Rosen, Barry P.; Zhu, Yong-Guan

    2011-01-01

    Arsenic (As) is a pervasive and ubiquitous environmental toxin that has created worldwide human health problems. However, there are few studies about how organisms detoxify As. Cyanobacteria are capable of both photolithotrophic growth in the light and heterotrophic growth in the dark and are ubiquitous in soils, aquatic systems, and wetlands. In this study, we investigated As biotransformation in three cyanobacterial species (Microcystis sp. PCC7806, Nostoc sp. PCC7120, and Synechocystis sp. PCC6803). Each accumulated large amounts of As, up to 0.39 g kg−1 dry weight, 0.45 g kg−1 dry weight, and 0.38 g kg−1 dry weight when treated with 100 μm sodium arsenite for 14 d, respectively. Inorganic arsenate and arsenite were the predominant species, with arsenate making up >80% of total As; methylated arsenicals were detected following exposure to higher As concentrations. When treated with arsenate for 6 weeks, cells of each cyanobacterium produced volatile arsenicals. The genes encoding the As(III) S-adenosylmethionine methyltransferase (ArsM) were cloned from these three cyanobacteria. When expressed in an As-hypersensitive strain of Escherichia coli, each conferred resistance to arsenite. Two of the ArsM homologs (SsArsM from Synechocystis sp. PCC6803 and NsArsM from Nostoc sp. PCC7120) were purified and were shown to methylate arsenite in vitro with trimethylarsine as the end product. Given that ArsM homologs are widespread in cyanobacteria, we propose that they play an important role in As biogeochemistry. PMID:21562336

  2. Spectroradiometric monitoring for open outdoor culturing of algae and cyanobacteria

    SciTech Connect

    Reichardt, Thomas A.; Collins, Aaron M.; McBride, Robert C.; Behnke, Craig A.; Timlin, Jerilyn A.

    2014-08-20

    We assess the measurement of hyperspectral reflectance for the outdoor monitoring of green algae and cyanobacteria cultures with a multi-channel, fiber-coupled spectroradiometer. Reflectance data acquired over a four-week period are interpreted via numerical inversion of a reflectance model, in which the above-water reflectance is expressed as a quadratic function of the single backscattering albedo, dependent on the absorption and backscatter coefficients. The absorption coefficient is treated as the sum of component spectra consisting of the cultured species (green algae or cyanobacteria), dissolved organic matter, and water (including the temperature dependence of the water absorption spectrum). The backscatter coefficient is approximated as the scaled Hilbert transform of the culture absorption spectrum with a wavelength-independent vertical offset. Additional terms in the reflectance model account for the pigment fluorescence features and the water surface reflection of sunlight and skylight. For both the green algae and cyanobacteria, the wavelength-independent vertical offset of the backscatter coefficient is found to scale linearly with daily dry weight measurements, providing the capability for a non-sampling measurement of biomass in outdoor ponds. Other fitting parameters in the reflectance model are compared to auxiliary measurements and physics-based calculations. The magnitudes of the sunlight and skylight water-surface contributions derived from the reflectance model compare favorably with Fresnel reflectance calculations, while the reflectance-derived quantum efficiency of Chl-a fluorescence is found to be in agreement with literature values. To conlclude, the water temperature derived from the reflectance model exhibits excellent agreement with thermocouple measurements during the morning hours and highlights significantly elevated temperatures in the afternoon hours.

  3. Spectroradiometric monitoring for open outdoor culturing of algae and cyanobacteria

    DOE PAGESBeta

    Reichardt, Thomas A.; Collins, Aaron M.; McBride, Robert C.; Behnke, Craig A.; Timlin, Jerilyn A.

    2014-08-20

    We assess the measurement of hyperspectral reflectance for the outdoor monitoring of green algae and cyanobacteria cultures with a multi-channel, fiber-coupled spectroradiometer. Reflectance data acquired over a four-week period are interpreted via numerical inversion of a reflectance model, in which the above-water reflectance is expressed as a quadratic function of the single backscattering albedo, dependent on the absorption and backscatter coefficients. The absorption coefficient is treated as the sum of component spectra consisting of the cultured species (green algae or cyanobacteria), dissolved organic matter, and water (including the temperature dependence of the water absorption spectrum). The backscatter coefficient is approximatedmore » as the scaled Hilbert transform of the culture absorption spectrum with a wavelength-independent vertical offset. Additional terms in the reflectance model account for the pigment fluorescence features and the water surface reflection of sunlight and skylight. For both the green algae and cyanobacteria, the wavelength-independent vertical offset of the backscatter coefficient is found to scale linearly with daily dry weight measurements, providing the capability for a non-sampling measurement of biomass in outdoor ponds. Other fitting parameters in the reflectance model are compared to auxiliary measurements and physics-based calculations. The magnitudes of the sunlight and skylight water-surface contributions derived from the reflectance model compare favorably with Fresnel reflectance calculations, while the reflectance-derived quantum efficiency of Chl-a fluorescence is found to be in agreement with literature values. To conlclude, the water temperature derived from the reflectance model exhibits excellent agreement with thermocouple measurements during the morning hours and highlights significantly elevated temperatures in the afternoon hours.« less

  4. The Northeast Cyanobacteria Monitoring Program: One Program, Three Opportunities for You To Get Involved!

    EPA Science Inventory

    If you ever have noticed a waterbody with a layer of green scum coating its surface or a slick green film resembling a paint spill, you likely have witnessed a cyanobacteria bloom. Cyanobacteria, sometimes referred to as blue-green algae, are tiny organisms found naturally in aqu...

  5. Cyanobacteria, Toxins and Indicators: Full-Scale Monitoring & Bench-Scale Treatment Studies

    EPA Science Inventory

    Summary of: 1) Lake Erie 2014 bloom season full-scale treatment plant monitoring data for cyanobacteria and cyanobacteria toxins; 2) Follow-up work to examine the impact of pre-oxidation on suspensions of intact toxin-producing cyanobacterial cells.

  6. CYANOBACTERIA AND THEIR TOXINS IN EPA'S DRINKING WATER CONTAMINANT CANDIDATE LIST

    EPA Science Inventory

    Cyanobacteria, and other algae, and their toxins are a group of microbial contaminants included on the CCL and are undergoing further study and evaluation. Although multiple cyanobacteria toxins have been detected in the United States, five categories of toxins are of particular ...

  7. Biogeochemical Activity of Siderophilic Cyanobacteria: Implications for Paleobiogeochemistry

    NASA Technical Reports Server (NTRS)

    Brown, Igor I.; Sarkisova, Svetlana A.; Auyeung, Weng S.; Garrison, Dan; Allen, Carlton C.; McKay, David S.

    2007-01-01

    Understanding the patterns of iron oxidation by cyanobacteria (CB) has tremendous importance for paleobiogeochemistry, since cyanobacteria are presumed to have been involved in the global oxidation of ferrous iron during the Precambrian (Cloud, 1973). B.K. Pierson (1999, 2000) first proposed to study iron deposition in iron-depositing hot springs (ID HS) as a model for Precambrian Fe(2+) oxidation. However, neither the iron-dependent physiology of individual species of CB inhabiting iron-depositing hot springs nor their interactions with minerals enriched with iron have been examined thoroughly. Such study could shed light on ancient iron turnover. Cyanobacterial species isolated from ID HS demonstrate elevated tolerance to colloidal Fe(3+) (= 1 mM), while a concentration of 0.4 mM proved toxic for mesophilic Synechocystis PCC 6803. Isolates from ID HS require 0.4-0.6 mM Fe3+ for maximal growth while the iron requirement for Synechocystis is approximately one order of magnitude lower. We have also demonstrated that thick polysaccharide sheaths around cells of CB isolated from ID HS serve as repositories for precipitated iron. The growth of the mesophilic cyanobacteria Phromidium aa in iron-saturated (0.6 mM) DH medium did not lead to iron precipitation on its filament surfaces. However, a 14.3 fil.2 culture, isolated from an ID HS and incubated under the same conditions, was covered with dense layer of precipitated iron. Our results, taken together with Pierson s data concerning the ability of Fe2+ to stimulate photosynthesis in natural CB mats in ID HS, suggest that CB inhabiting ID HS may constitute a new group of the extremophiles - siderophilic CB. Our recent experiments have revealed for the first time that CB isolates from ID HS are also capable of biodeterioration - the etching of minerals, in particular glasses enriched with Fe, Al, Ti, O, and Si. Thus, Precambrian siderophilic cyanobacteria and their predecessors could have been involved not only in iron

  8. Cyanobacteria enhance methylmercury production: a hypothesis tested in the periphyton of two lakes in the Pantanal floodplain, Brazil.

    PubMed

    Lázaro, Wilkinson L; Guimarães, Jean Remy D; Ignácio, Aurea R A; Da Silva, Carolina J; Díez, Sergi

    2013-07-01

    The toxic potential of mercury (Hg) in aquatic systems is due to the presence and production of methylmercury (MeHg). Recent studies in tropical floodplain environments showed that periphyton associated with the roots of aquatic macrophytes produce MeHg. Periphyton communities are the first link in the food chain and one of the main MeHg sources in aquatic environments. The aim of this work was to test the hypotheses that the algal community structure affects potential methylation, and ecologically distinct communities with different algal and bacterial densities directly affect the formation of MeHg in the roots of macrophytes. To evaluate these, net MeHg production in the roots of Eichhornia crassipes in relation to the taxonomic structure of associated periphytic algae was evaluated. Macrophyte root samples were collected in the dry and flood season from two floodplain lakes in the Pantanal (Brazil). These lakes have different ecological conditions as a function of their lateral hydrological connectivity with the Paraguay River that is different during times of drought. Results indicated that MeHg production was higher in the flood season than in the dry season. MeHg production rates were higher in the disconnected lake in comparison to the connected lake during the dry season. MeHg production exhibited a strong positive co-variation with cyanobacteria abundance (R(2)=0.78; p<0.0001 in dry; R(2)=0.40; p=0.029 in flood) and with total algal biomass (R(2)=0.86; p<0.0001), and a negative co-variation with Zygnemaphyceae (R(2)=0.50; p=0.0018) in the lake community in dry season. This indicates that ecological conditions that favour the establishment and development of cyanobacteria are associated with higher rates of methylation in aquatic systems. This suggests that cyanobacteria could be a proxy for sites of MeHg production in some natural aquatic environments.

  9. Modeling the Role of pH on Baltic Sea Cyanobacteria

    PubMed Central

    Hinners, Jana; Hofmeister, Richard; Hense, Inga

    2015-01-01

    We simulate pH-dependent growth of cyanobacteria with an ecosystem model for the central Baltic Sea. Four model components—a life cycle model of cyanobacteria, a biogeochemical model, a carbonate chemistry model and a water column model—are coupled via the framework for aquatic biogeochemical models. The coupled model is forced by the output of a regional climate model, based on the A1B emission scenario. With this coupled model, we perform simulations for the period 1968–2098. Our simulation experiments suggest that in the future, cyanobacteria growth is hardly affected by the projected pH decrease. However, in the simulation phase prior to 1980, cyanobacteria growth and N2-fixation are limited by the relatively high pH. The observed absence of cyanobacteria before the 1960s may thus be explained not only by lower eutrophication levels, but also by a higher alkalinity. PMID:25830591

  10. Effects of herbivore exclusion and nutrient enrichment on coral reef macroalgae and cyanobacteria

    NASA Astrophysics Data System (ADS)

    Thacker, R.; Ginsburg, D.; Paul, V.

    2001-05-01

    Although phase shifts on coral reefs from coral-dominated to algal-dominated communities have been attributed to the effects of increased nutrient availability due to eutrophication and reduced herbivore abundance due to overfishing and disease, these factors have rarely been manipulated simultaneously. In addition, few studies have considered the effects of these factors on benthic, filamentous cyanobacteria (blue-green algae) as well as macroalgae. We used a combination of herbivore-exclusion cages and nutrient enrichment to manipulate herbivore abundance and nutrient availability, and measured the impacts of these treatments on macroalgal and cyanobacterial community structure. In the absence of cages, surface cover of the cyanobacterium Tolypothrix sp. decreased, while surface cover of the cyanobacteria Oscillatoria spp. increased. Cyanobacterial cover decreased in partial cages, and Tolypothrix sp. cover decreased further in full cages. Lower cyanobacterial cover and biomass were correlated with higher macroalgal cover and biomass. Dictyota bartayresiana dominated the partial cages, while Padina tenuis and Tolypiocladia glomerulata recruited into the full cages. Palatability assays demonstrated that herbivore-exclusion shifted macroalgal species composition from relatively unpalatable to relatively palatable species. Nutrient enrichment interacted with herbivore exclusion to increase the change in cover of D. bartayresiana in the uncaged and fully caged plots, but did not affect the final biomass of D. bartayresiana among treatments. Nutrient enrichment did not significantly affect the cover or biomass of any other taxa. These results stress the critical role of herbivory in determining coral reef community structure and suggest that the relative palatabilities of dominant algae, as well as algal growth responses to nutrient enrichment, will determine the potential for phase shifts to algal-dominated communities.

  11. Production of greenhouse-grown biocrust mosses and associated cyanobacteria to rehabilitate dryland soil function

    USGS Publications Warehouse

    Antoninka, Anita; Bowker, Matthew A.; Reed, Sasha C.; Doherty, Kyle

    2016-01-01

    Mosses are an often-overlooked component of dryland ecosystems, yet they are common members of biological soil crust communities (biocrusts) and provide key ecosystem services, including soil stabilization, water retention, carbon fixation, and housing of N2 fixing cyanobacteria. Mosses are able to survive long dry periods, respond rapidly to precipitation, and reproduce vegetatively. With these qualities, dryland mosses have the potential to be an excellent dryland restoration material. Unfortunately, dryland mosses are often slow growing in nature, and ex situ cultivation methods are needed to enhance their utility. Our goal was to determine how to rapidly produce, vegetatively, Syntrichia caninervis and S. ruralis, common and abundant moss species in drylands of North America and elsewhere, in a greenhouse. We manipulated the length of hydration on a weekly schedule (5, 4, 3, or 2 days continuous hydration per week), crossed with fertilization (once at the beginning, monthly, biweekly, or not at all). Moss biomass increased sixfold for both species in 4 months, an increase that would require years under dryland field conditions. Both moss species preferred short hydration and monthly fertilizer. Remarkably, we also unintentionally cultured a variety of other important biocrust organisms, including cyanobacteria and lichens. In only 6 months, we produced functionally mature biocrusts, as evidenced by high productivity and ecosystem-relevant levels of N2 fixation. Our results suggest that biocrust mosses might be the ideal candidate for biocrust cultivation for restoration purposes. With optimization, these methods are the first step in developing a moss-based biocrust rehabilitation technology.

  12. Biosynthesis of anatoxin-a and analogues (anatoxins) in cyanobacteria.

    PubMed

    Méjean, Annick; Paci, Guillaume; Gautier, Valérie; Ploux, Olivier

    2014-12-01

    Freshwater cyanobacteria produce secondary metabolites that are toxic to humans and animals, the so-called cyanotoxins. Among them, anatoxin-a and homoanatoxin-a are potent neurotoxins that are agonists of the nicotinic acetylcholine receptor. These alkaloids provoke a rapid death if ingested at low doses. Recently, the cluster of genes responsible for the biosynthesis of these toxins, the ana cluster, has been identified in Oscillatoria sp. PCC 6506, and a biosynthetic pathway was proposed. This biosynthesis was reconstituted in vitro using purified enzymes confirming the predicted pathway. One of the enzymes, AnaB a prolyl-acyl carrier protein oxidase, was crystallized and its three dimensional structure solved confirming its reaction mechanism. Three other ana clusters have now been identified and sequenced in other cyanobacteria. These clusters show similarities and some differences suggesting a common evolutionary origin. In particular, the cluster from Cylindrospermum stagnale PCC 7417, possesses an extra gene coding for an F420-dependent oxidoreductase that is likely involved in the biosynthesis of dihydroanatoxin-a. This review summarizes all these new data and discusses them in relation to the production of anatoxins in the environment.

  13. Mining Genomes of Marine Cyanobacteria for Elements of Zinc Homeostasis

    PubMed Central

    Barnett, James P.; Millard, Andrew; Ksibe, Amira Z.; Scanlan, David J.; Schmid, Ralf; Blindauer, Claudia Andrea

    2012-01-01

    Zinc is a recognized essential element for the majority of organisms, and is indispensable for the correct function of hundreds of enzymes and thousands of regulatory proteins. In aquatic photoautotrophs including cyanobacteria, zinc is thought to be required for carbonic anhydrase and alkaline phosphatase, although there is evidence that at least some carbonic anhydrases can be cambialistic, i.e., are able to acquire in vivo and function with different metal cofactors such as Co2+ and Cd2+. Given the global importance of marine phytoplankton, zinc availability in the oceans is likely to have an impact on both carbon and phosphorus cycles. Zinc concentrations in seawater vary over several orders of magnitude, and in the open oceans adopt a nutrient-like profile. Most studies on zinc handling by cyanobacteria have focused on freshwater strains and zinc toxicity; much less information is available on marine strains and zinc limitation. Several systems for zinc homeostasis have been characterized in the freshwater species Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803, but little is known about zinc requirements or zinc handling by marine species. Comparative metallo-genomics has begun to explore not only the putative zinc proteome, but also specific protein families predicted to have an involvement in zinc homeostasis, including sensors for excess and limitation (SmtB and its homologs as well as Zur), uptake systems (ZnuABC), putative intracellular zinc chaperones (COG0523) and metallothioneins (BmtA), and efflux pumps (ZiaA and its homologs). PMID:22514551

  14. Inhibition of coral recruitment by macroalgae and cyanobacteria

    USGS Publications Warehouse

    Kuffner, I.B.; Walters, L.J.; Becerro, M.A.; Paul, V.J.; Ritson-Williams, R.; Beach, K.S.

    2006-01-01

    Coral recruitment is a key process in the maintenance and recovery of coral reef ecosystems. While intense competition between coral and algae is often assumed on reefs that have undergone phase shifts from coral to algal dominance, data examining the competitive interactions involved, particularly during the larval and immediate post-settlement stage, are scarce. Using a series of field and outdoor seawater table experiments, we tested the hypothesis that common species of macroalgae and cyanobacteria inhibit coral recruitment. We examined the effects of Lyngbya spp., Dictyota spp., Lobophora variegata (J. V. Lamouroux) Womersley, and Chondrophycus poiteaui (J. V. Lamouroux) Nam (formerly Laurencia poiteaui) on the recruitment success of Porites astreoides larvae. All species but C. poiteaui caused either recruitment inhibition or avoidance behavior in P. astreoides larvae, while L. confervoides and D. menstrualis significantly increased mortality rates of P. astreoides recruits. We also tested the effect of some of these macrophytes on larvae of the gorgonian octocoral Briareum asbestinum. Exposure to Lyngbya majuscula reduced survival and recruitment in the octocoral larvae. Our results provide evidence that algae and cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. On reefs experiencing phase shifts or temporary algal blooms, the restocking of adult coral populations may be slowed due to recruitment inhibition, thereby perpetuating reduced coral cover and limiting coral community recovery. ?? Inter-Research 2006.

  15. Sensing and responding to UV-A in cyanobacteria.

    PubMed

    Moon, Yoon-Jung; Kim, Seung Il; Chung, Young-Ho

    2012-12-03

    Ultraviolet (UV) radiation can cause stresses or act as a photoregulatory signal depending on its wavelengths and fluence rates. Although the most harmful effects of UV on living cells are generally attributed to UV-B radiation, UV-A radiation can also affect many aspects of cellular processes. In cyanobacteria, most studies have concentrated on the damaging effect of UV and defense mechanisms to withstand UV stress. However, little is known about the activation mechanism of signaling components or their pathways which are implicated in the process following UV irradiation. Motile cyanobacteria use a very precise negative phototaxis signaling system to move away from high levels of solar radiation, which is an effective escape mechanism to avoid the detrimental effects of UV radiation. Recently, two different UV-A-induced signaling systems for regulating cyanobacterial phototaxis were characterized at the photophysiological and molecular levels. Here, we review the current understanding of the UV-A mediated signaling pathways in the context of the UV-A perception mechanism, early signaling components, and negative phototactic responses. In addition, increasing evidences supporting a role of pterins in response to UV radiation are discussed. We outline the effect of UV-induced cell damage, associated signaling molecules, and programmed cell death under UV-mediated oxidative stress.

  16. Sensing and Responding to UV-A in Cyanobacteria

    PubMed Central

    Moon, Yoon-Jung; Kim, Seung Il; Chung, Young-Ho

    2012-01-01

    Ultraviolet (UV) radiation can cause stresses or act as a photoregulatory signal depending on its wavelengths and fluence rates. Although the most harmful effects of UV on living cells are generally attributed to UV-B radiation, UV-A radiation can also affect many aspects of cellular processes. In cyanobacteria, most studies have concentrated on the damaging effect of UV and defense mechanisms to withstand UV stress. However, little is known about the activation mechanism of signaling components or their pathways which are implicated in the process following UV irradiation. Motile cyanobacteria use a very precise negative phototaxis signaling system to move away from high levels of solar radiation, which is an effective escape mechanism to avoid the detrimental effects of UV radiation. Recently, two different UV-A-induced signaling systems for regulating cyanobacterial phototaxis were characterized at the photophysiological and molecular levels. Here, we review the current understanding of the UV-A mediated signaling pathways in the context of the UV-A perception mechanism, early signaling components, and negative phototactic responses. In addition, increasing evidences supporting a role of pterins in response to UV radiation are discussed. We outline the effect of UV-induced cell damage, associated signaling molecules, and programmed cell death under UV-mediated oxidative stress. PMID:23208372

  17. Phylogeny and Biogeography of Cyanobacteria and Their Produced Toxins

    PubMed Central

    Moreira, Cristiana; Vasconcelos, Vitor; Antunes, Agostinho

    2013-01-01

    Phylogeny is an evolutionary reconstruction of the past relationships of DNA or protein sequences and it can further be used as a tool to assess population structuring, genetic diversity and biogeographic patterns. In the microbial world, the concept that everything is everywhere is widely accepted. However, it is much debated whether microbes are easily dispersed globally or whether they, like many macro-organisms, have historical biogeographies. Biogeography can be defined as the science that documents the spatial and temporal distribution of a given taxa in the environment at local, regional and continental scales. Speciation, extinction and dispersal are proposed to explain the generation of biogeographic patterns. Cyanobacteria are a diverse group of microorganisms that inhabit a wide range of ecological niches and are well known for their toxic secondary metabolite production. Knowledge of the evolution and dispersal of these microorganisms is still limited, and further research to understand such topics is imperative. Here, we provide a compilation of the most relevant information regarding these issues to better understand the present state of the art as a platform for future studies, and we highlight examples of both phylogenetic and biogeographic studies in non-symbiotic cyanobacteria and cyanotoxins. PMID:24189276

  18. Localisation and interactions of the Vipp1 protein in cyanobacteria

    PubMed Central

    Bryan, Samantha J; Burroughs, Nigel J; Shevela, Dmitriy; Yu, Jianfeng; Rupprecht, Eva; Liu, Lu-Ning; Mastroianni, Giulia; Xue, Quan; Llorente-Garcia, Isabel; Leake, Mark C; Eichacker, Lutz A; Schneider, Dirk; Nixon, Peter J; Mullineaux, Conrad W

    2014-01-01

    The Vipp1 protein is essential in cyanobacteria and chloroplasts for the maintenance of photosynthetic function and thylakoid membrane architecture. To investigate its mode of action we generated strains of the cyanobacteria Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942 in which Vipp1 was tagged with green fluorescent protein at the C-terminus and expressed from the native chromosomal locus. There was little perturbation of function. Live-cell fluorescence imaging shows dramatic relocalisation of Vipp1 under high light. Under low light, Vipp1 is predominantly dispersed in the cytoplasm with occasional concentrations at the outer periphery of the thylakoid membranes. High light induces Vipp1 coalescence into localised puncta within minutes, with net relocation of Vipp1 to the vicinity of the cytoplasmic membrane and the thylakoid membranes. Pull-downs and mass spectrometry identify an extensive collection of proteins that are directly or indirectly associated with Vipp1 only after high-light exposure. These include not only photosynthetic and stress-related proteins but also RNA-processing, translation and protein assembly factors. This suggests that the Vipp1 puncta could be involved in protein assembly. One possibility is that Vipp1 is involved in the formation of stress-induced localised protein assembly centres, enabling enhanced protein synthesis and delivery to membranes under stress conditions. PMID:25308470

  19. Cyanobacteria and microalgae: a positive prospect for biofuels.

    PubMed

    Parmar, Asha; Singh, Niraj Kumar; Pandey, Ashok; Gnansounou, Edgard; Madamwar, Datta

    2011-11-01

    Biofuel-bioenergy production has generated intensive interest due to increased concern regarding limited petroleum-based fuel supplies and their contribution to atmospheric CO2 levels. Biofuel research is not just a matter of finding the right type of biomass and converting it to fuel, but it must also be economically sustainable on large-scale. Several aspects of cyanobacteria and microalgae such as oxygenic photosynthesis, high per-acre productivity, non-food based feedstock, growth on non-productive and non-arable land, utilization of wide variety of water sources (fresh, brackish, seawater and wastewater) and production of valuable co-products along with biofuels have combined to capture the interest of researchers and entrepreneurs. Currently, worldwide biofuels mainly in focus include biohydrogen, bioethanol, biodiesel and biogas. This review focuses on cultivation and harvesting of cyanobacteria and microalgae, possible biofuels and co-products, challenges for cyanobacterial and microalgal biofuels and the approaches of genetic engineering and modifications to increase biofuel production.

  20. Rapid determination of cytokinins and auxin in cyanobacteria.

    PubMed

    Hussain, Anwar; Krischke, Markus; Roitsch, Thomas; Hasnain, Shahida

    2010-11-01

    Five cyanobacterial strains, Anabaena sp. Ck1, Oscillatoria sp. Ck2, Phormidium sp. Ck3, Chroococcidiopsis sp. Ck4, and Synechosystis sp. Ck5 were selected for their positive cytokinins-like activity using cucumber cotyledon bioassay and GUS assay in Arabidopsis ARR5::GUS. Classical cucumber cotyledon bioassay was modified for direct screening of cyanobacteria avoiding need for extraction and purification. Cytokinins from cyanobacteria were absorbed onto filter paper which was then assayed for cytokinins-like activity. A rapid chromatographic method was developed for the simultaneous determination of cytokinins and indole-3-acetic acid (IAA). Cyanobacterial biomass (50-100 mg) and cell-free culture filtrate were extracted in Bieleski buffer and purified by solid-phase extraction. The extract was used to determine phytohormones by ultra performance liquid chromatography and electrospray ionization-tandem mass spectrometry in positive and negative modes, respectively, with multiple reactions monitoring. Stable isotope-labeled cytokinins and IAA standards were added in the samples to follow recovery of the compounds and method validation. Five cytokinins determined in the selected strains were Zeatin (cis and trans isomers), Zeatin riboside, Dihydrozeatin riboside, and zeatin-o-glucoside. The strains were shown to accumulate as well as release the phytohormones.

  1. Cyanobacteria and microalgae: a positive prospect for biofuels.

    PubMed

    Parmar, Asha; Singh, Niraj Kumar; Pandey, Ashok; Gnansounou, Edgard; Madamwar, Datta

    2011-11-01

    Biofuel-bioenergy production has generated intensive interest due to increased concern regarding limited petroleum-based fuel supplies and their contribution to atmospheric CO2 levels. Biofuel research is not just a matter of finding the right type of biomass and converting it to fuel, but it must also be economically sustainable on large-scale. Several aspects of cyanobacteria and microalgae such as oxygenic photosynthesis, high per-acre productivity, non-food based feedstock, growth on non-productive and non-arable land, utilization of wide variety of water sources (fresh, brackish, seawater and wastewater) and production of valuable co-products along with biofuels have combined to capture the interest of researchers and entrepreneurs. Currently, worldwide biofuels mainly in focus include biohydrogen, bioethanol, biodiesel and biogas. This review focuses on cultivation and harvesting of cyanobacteria and microalgae, possible biofuels and co-products, challenges for cyanobacterial and microalgal biofuels and the approaches of genetic engineering and modifications to increase biofuel production. PMID:21924898

  2. Application of PCR and real-time PCR for monitoring cyanobacteria, Microcystis spp. and Cylindrospermopsis raciborskii in Macau freshwater reservoir

    NASA Astrophysics Data System (ADS)

    Zhang, Weiying; Lou, Inchio; Ung, Wai Kin; Kong, Yijun; Mok, Kai Meng

    2014-06-01

    Freshwater algal blooms have become a growing concern world-wide. They are caused by a high level of cyanobacteria, predominantly Microcystis spp. and Cylindrospermopsis raciborskii, which can produce microcystin and cylindrospermopsin, respectively. Longtime exposure to these cyanotoxins may affect public health, thus reliable detection, quantification, and enumeration of these harmful algae species has become a priority in water quality management. Traditional manual enumeration of algal bloom cells primarily involves microscopic identification which limited by inaccuracy and time-consumption.With the development of molecular techniques and an increasing number of microbial sequences available in the Genbank database, the use of molecular methods can be used for more rapid, reliable, and accurate detection and quantification. In this study, multiplex polymerase chain reaction (PCR) and real-time quantitative PCR (qPCR) techniques were developed and applied for monitoring cyanobacteria Microcystis spp. and C. raciborskii in the Macau Storage Reservoir (MSR). The results showed that the techniques were successful for identifying and quantifying the species in pure cultures and mixed cultures, and proved to be a potential application for water sampling in MSR. When the target species were above 1 million cells/L, similar cell numbers estimated by microscopic enumeration and qPCR were obtained. Further quantification in water samples indicated that the ratio of the estimated number of cell by microscopy and qPCR was 0.4-12.9 for cyanobacteria and 0.2-3.9 for C. raciborskii. However, Microcystis spp. was not observed by manual enumeration, while it was detected at low levels by qPCR, suggesting that qPCR is more sensitive and accurate. Thus the molecular approaches provide an additional reliable monitoring option to traditional microscopic enumeration for the ecosystems monitoring program.

  3. [Microcystin safety study during Cyanobacteria removal by pressure enhanced coagulation process].

    PubMed

    Jiang, Xin-Yue; Luan, Qing; Cong, Hai-Bing; Xu, Si-Tao; Liu, Yu-Jiao; Zhu, Xue-Yuan

    2014-11-01

    Pressure enhanced coagulation and sedimentation technique is an effective way for blue algae treatment. It is not clear whether Cyanobacteria balloon rupture will cause Cyanobacteria cells rupture, resulting in high intracellular concentrations of microcystin LR leak into the water, affecting drinking water safety. Therefore, in this study experimental comparative study of pressure and pre-oxidation of water containing Cyanobacteria was carried out to examine the microcystin LR concentration changes and Cyanobacteria removal efficiency. The results showed that microcystin concentration increase was not significant by the pre-treatment with Cyanobacteria water pressure, while the pre-oxidation process caused a significant increase in the concentration of microcystin. After 0.5-0.8 MPa pressure coagulation and sedimentation, removal of Cyanobacteria basically was over 90%, up to 93.5%, while the removal rate by pre-oxidation was low and unstable. Effluent turbidity is also significantly better in the pre-pressure method than the pre-oxidation. The results indicated that pressure enhanced coagulation is a safe and reliable method for Cyanobacteria removal.

  4. Large-scale bioprospecting of cyanobacteria, micro- and macroalgae from the Aegean Sea.

    PubMed

    Montalvão, Sofia; Demirel, Zeliha; Devi, Prabha; Lombardi, Valter; Hongisto, Vesa; Perälä, Merja; Hattara, Johannes; Imamoglu, Esra; Tilvi, Supriya Shet; Turan, Gamze; Dalay, Meltem Conk; Tammela, Päivi

    2016-05-25

    Marine organisms constitute approximately one-half of the total global biodiversity, being rich reservoirs of structurally diverse biofunctional components. The potential of cyanobacteria, micro- and macroalgae as sources of antimicrobial, antitumoral, anti-inflammatory, and anticoagulant compounds has been reported extensively. Nonetheless, biological activities of marine fauna and flora of the Aegean Sea have remained poorly studied when in comparison to other areas of the Mediterranean Sea. In this study, we screened the antimicrobial, antifouling, anti-inflammatory and anticancer potential of in total 98 specimens collected from the Aegean Sea. Ethanol extract of diatom Amphora cf capitellata showed the most promising antimicrobial results against Candida albicans while the extract of diatom Nitzschia communis showed effective results against Gram-positive bacterium, S. aureus. Extracts from the red alga Laurencia papillosa and from three Cystoseira species exhibited selective antiproliferative activity against cancer cell lines and an extract from the brown alga Dilophus fasciola showed the highest anti-inflammatory activity as measured in primary microglial and astrocyte cell cultures as well as by the reduction of proinflammatory cytokines. In summary, our study demonstrates that the Aegean Sea is a rich source of species that possess interesting potential for developing industrial applications. PMID:26902670

  5. Proteomic analyses of the response of cyanobacteria to different stress conditions.

    PubMed

    Castielli, Ornella; De la Cerda, Berta; Navarro, José A; Hervás, Manuel; De la Rosa, Miguel A

    2009-06-01

    Cyanobacteria are significant contributors to global photosynthetic productivity, thus making it relevant to study how the different environmental stresses can alter their physiological activities. Here, we review the current research work on the response of cyanobacteria to different kinds of stress, mainly focusing on their response to metal stress as studied by using the modern proteomic tools. We also report a proteomic analysis of plastocyanin and cytochrome c(6) deletion mutants of the cyanobacterium Synechocystis sp. PCC 6803 grown under copper or iron deprivation, as compared to wild-type cells, so as to get a further understanding of the metal homeostasis in cyanobacteria and their response to changing environmental conditions.

  6. Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering.

    PubMed

    Quintana, Naira; Van der Kooy, Frank; Van de Rhee, Miranda D; Voshol, Gerben P; Verpoorte, Robert

    2011-08-01

    The need to develop and improve sustainable energy resources is of eminent importance due to the finite nature of our fossil fuels. This review paper deals with a third generation renewable energy resource which does not compete with our food resources, cyanobacteria. We discuss the current state of the art in developing different types of bioenergy (ethanol, biodiesel, hydrogen, etc.) from cyanobacteria. The major important biochemical pathways in cyanobacteria are highlighted, and the possibility to influence these pathways to improve the production of specific types of energy forms the major part of this review.

  7. Diversity of Diazotrophic Unicellular Cyanobacteria in the Tropical North Atlantic Ocean

    PubMed Central

    Falcón, Luisa I.; Cipriano, Frank; Chistoserdov, Andrei Y.; Carpenter, Edward J.

    2002-01-01

    We present data on the genetic diversity and phylogenetic affinities of N2-fixing unicellular cyanobacteria in the plankton of the tropical North Atlantic Ocean. Our dinitrogenase gene (nifH) sequences grouped together with a group of cyanobacteria from the subtropical North Pacific; another subtropical North Pacific group was only distantly related. Most of the 16S ribosomal DNA sequences from our tropical North Atlantic samples were closely allied with sequences from a symbiont of the diatom Climacodium frauenfeldianum. These findings suggest a complex pattern of evolutionary and ecological divergence among unicellular cyanobacteria within and between ocean basins. PMID:12406777

  8. Photo-electrochemical communication between cyanobacteria (Leptolyngbia sp.) and osmium redox polymer modified electrodes.

    PubMed

    Hasan, Kamrul; Bekir Yildiz, Huseyin; Sperling, Eva; Conghaile, Peter Ó; Packer, Michael A; Leech, Dónal; Hägerhäll, Cecilia; Gorton, Lo

    2014-12-01

    Photosynthetic microbial fuel cells (PMFCs) are an emerging technology for renewable solar energy conversion. Major efforts have been made to explore the electrogenic activity of cyanobacteria, mostly using practically unsustainable reagents. Here we report on photocurrent generation (≈8.64 μA cm(-2)) from cyanobacteria immobilized on electrodes modified with an efficient electron mediator, an Os(2+/3+) redox polymer. Upon addition of ferricyanide to the electrolyte, cyanobacteria generate the maximum current density of ≈48.2 μA cm(-2).

  9. Photo-electrochemical communication between cyanobacteria (Leptolyngbia sp.) and osmium redox polymer modified electrodes.

    PubMed

    Hasan, Kamrul; Bekir Yildiz, Huseyin; Sperling, Eva; Conghaile, Peter Ó; Packer, Michael A; Leech, Dónal; Hägerhäll, Cecilia; Gorton, Lo

    2014-12-01

    Photosynthetic microbial fuel cells (PMFCs) are an emerging technology for renewable solar energy conversion. Major efforts have been made to explore the electrogenic activity of cyanobacteria, mostly using practically unsustainable reagents. Here we report on photocurrent generation (≈8.64 μA cm(-2)) from cyanobacteria immobilized on electrodes modified with an efficient electron mediator, an Os(2+/3+) redox polymer. Upon addition of ferricyanide to the electrolyte, cyanobacteria generate the maximum current density of ≈48.2 μA cm(-2). PMID:25325401

  10. Spatial and temporal distribution of cyanobacteria in Batticaloa Lagoon.

    PubMed

    Harris, Jalaldeen Mohamed; Vinobaba, Periyathamby; Kularatne, Ranil Kavindra Asela; Ellawala Kankanamge, Champika

    2016-09-01

    The necessity to understand the relationship between cyanobacterial species abundance and water quality variations in coastal lagoons is crucial to develop strategies to prevent further cyanobacterial proliferation. This paper evaluates the relationship between water quality variations on the distribution of cyanobacteria during a 12-month period in Batticaloa Lagoon (Sri Lanka) using Redundancy analysis and Pearson correlations. Drastic variations in pH, temperature, salinity, dissolved oxygen (DO) and total phosphorus (TP) levels were reported, but not turbidity and NO3(-). This brackish waterbody is hypereutrophic (TP levels>0.1mg/L). The cyanobacterial community contained 13 genera and 22 species. NO3(-), TP and turbidity levels positively influenced cyanobacterial abundance during all seasons indicating that nutrient (largely phosphorus) and sediment entry control is highly crucial along with periodic monitoring of cyanobacterial growth. PMID:27593288

  11. Molluscicidal metabolites from an assemblage of Palmyra Atoll cyanobacteria.

    PubMed

    Pereira, Alban R; Etzbach, Lena; Engene, Niclas; Müller, Rolf; Gerwick, William H

    2011-05-27

    Molluscicides can play an important role in the control of schistosomiasis because snails of the genus Biomphalaria act as intermediate hosts for the parasite. Schistosomiasis is one of 13 neglected tropical diseases with high morbidity and mortality that collectively affect one billion of the world's poorest population, mainly in developing countries. Thiopalmyrone (1) and palmyrrolinone (2), metabolites isolated from extracts of a Palmyra Atoll environmental assemblage of two cyanobacteria, cf. Oscillatoria and Hormoscilla spp., represent new and potent molluscicidal chemotypes against Biomphalaria glabrata (LC50=8.3 and 6.0 μM, respectively). A slight enhancement in molluscicidal effect (LC50=5.0 μM) was observed when these two natural products were utilized as an equimolar binary mixture.

  12. Biodegradation and Utilization of Organophosphorus Pesticide Malathion by Cyanobacteria

    PubMed Central

    Ibrahim, Wael M.; Karam, Mohamed A.; El-Shahat, Reda M.; Adway, Asmaa A.

    2014-01-01

    Three strains of filamentous Cyanobacteria were used to study their growth and utilization of organophosphorus pesticide malathion. A sharp decrease in the growth of the algal strains was observed by increasing the concentration of malathion. Amongst them Nostoc muscorum tolerated different concentrations and was recorded as the highest efficient strain for biodegradation (91%) of this compound. Moreover, carbohydrate and protein content of their cells overtopped the other strains especially at higher concentrations. The algal strains were further subjected to grow under P-limitation in absence and presence of malathion. Although, the algal growth under P-limitation recorded a very poor level, a massive enhanced growth and phosphorous content of cells were obtained when the P-limited medium was amended with malathion. This study clarified that N. muscorum with its capability to utilize malathion as a sole phosphorous source is considered as an inexpensive and efficient biotechnology for remediation of organophosphorus pesticide from contaminated wastewater. PMID:24864237

  13. The phycobilisomes: an early requisite for efficient photosynthesis in cyanobacteria

    PubMed Central

    Singh, Niraj Kumar; Sonani, Ravi Raghav; Rastogi, Rajesh Prasad; Madamwar, Datta

    2015-01-01

    Cyanobacteria trap light energy by arrays of pigment molecules termed “phycobilisomes (PBSs)”, organized proximal to "reaction centers" at which chlorophyll perform the energy transduction steps with highest quantum efficiency. PBSs, composed of sequential assembly of various chromophorylated phycobiliproteins (PBPs), as well as nonchromophoric, basic and hydrophobic polypeptides called linkers. Atomic resolution structure of PBP is a heterodimer of two structurally related polypeptides but distinct specialised polypeptides- a and ß, made up of seven alpha-helices each which played a crucial step in evolution of PBPs. PBPs carry out various light dependent responses such as complementary chromatic adaptation. The aim of this review is to summarize and discuss the recent progress in this field and to highlight the new and the questions that remain unresolved. PMID:26417362

  14. UV-inducible DNA repair in the cyanobacteria Anabaena spp

    SciTech Connect

    Levine, E.; Thiel, T.

    1987-09-01

    Strains of the filamentous cyanobacteria Anabaena spp. were capable of very efficient photoreactivation of UV irradiation-induced damage to DNA. Cells were resistant to several hundred joules of UV irradiation per square meter under conditions that allowed photoreactivation, and they also photoreactivated UV-damaged cyanophage efficiently. Reactivation of UV-irradiated cyanophage (Weigle reactivation) also occurred; UV irradiation of host cells greatly enhanced the plaque-forming ability of irradiated phage under nonphotoreactivating conditions. Postirradiation incubation of the host cells under conditions that allowed photoreactivation abolished the ability of the cells to perform Weigle reactivation of cyanophage N-1. Mitomycin C also induced Weigle reactivation of cyanophage N-1, but nalidixic acid did not. The inducible repair system (defined as the ability to perform Weigle reactivation of cyanophages) was relatively slow and inefficient compared with photoreactivation.

  15. Metabolic engineering of cyanobacteria for the synthesis of commodity products.

    PubMed

    Angermayr, S Andreas; Gorchs Rovira, Aleix; Hellingwerf, Klaas J

    2015-06-01

    Through metabolic engineering cyanobacteria can be employed in biotechnology. Combining the capacity for oxygenic photosynthesis and carbon fixation with an engineered metabolic pathway allows carbon-based product formation from CO(2), light, and water directly. Such cyanobacterial 'cell factories' are constructed to produce biofuels, bioplastics, and commodity chemicals. Efforts of metabolic engineers and synthetic biologists allow the modification of the intermediary metabolism at various branching points, expanding the product range. The new biosynthesis routes 'tap' the metabolism ever more efficiently, particularly through the engineering of driving forces and utilization of cofactors generated during the light reactions of photosynthesis, resulting in higher product titers. High rates of carbon rechanneling ultimately allow an almost-complete allocation of fixed carbon to product above biomass. PMID:25908503

  16. Nuclear magnetic resonance spectroscopy of the circadian clock of cyanobacteria.

    PubMed

    Chang, Yong-Gang; Tseng, Roger; Kuo, Nai-Wei; LiWang, Andy

    2013-07-01

    The most well-understood circadian clock at the level of molecular mechanisms is that of cyanobacteria. This overview is on how solution-state nuclear magnetic resonance (NMR) spectroscopy has contributed to this understanding. By exciting atomic spin-½ nuclei in a strong magnetic field, NMR obtains information on their chemical environments, inter-nuclear distances, orientations, and motions. NMR protein samples are typically aqueous, often at near-physiological pH, ionic strength, and temperature. The level of information obtainable by NMR depends on the quality of the NMR sample, by which we mean the solubility and stability of proteins. Here, we use examples from our laboratory to illustrate the advantages and limitations of the technique. PMID:23667047

  17. Metabolic engineering of cyanobacteria for the synthesis of commodity products.

    PubMed

    Angermayr, S Andreas; Gorchs Rovira, Aleix; Hellingwerf, Klaas J

    2015-06-01

    Through metabolic engineering cyanobacteria can be employed in biotechnology. Combining the capacity for oxygenic photosynthesis and carbon fixation with an engineered metabolic pathway allows carbon-based product formation from CO(2), light, and water directly. Such cyanobacterial 'cell factories' are constructed to produce biofuels, bioplastics, and commodity chemicals. Efforts of metabolic engineers and synthetic biologists allow the modification of the intermediary metabolism at various branching points, expanding the product range. The new biosynthesis routes 'tap' the metabolism ever more efficiently, particularly through the engineering of driving forces and utilization of cofactors generated during the light reactions of photosynthesis, resulting in higher product titers. High rates of carbon rechanneling ultimately allow an almost-complete allocation of fixed carbon to product above biomass.

  18. The phycobilisomes: an early requisite for efficient photosynthesis in cyanobacteria.

    PubMed

    Singh, Niraj Kumar; Sonani, Ravi Raghav; Rastogi, Rajesh Prasad; Madamwar, Datta

    2015-01-01

    Cyanobacteria trap light energy by arrays of pigment molecules termed "phycobilisomes (PBSs)", organized proximal to "reaction centers" at which chlorophyll perform the energy transduction steps with highest quantum efficiency. PBSs, composed of sequential assembly of various chromophorylated phycobiliproteins (PBPs), as well as nonchromophoric, basic and hydrophobic polypeptides called linkers. Atomic resolution structure of PBP is a heterodimer of two structurally related polypeptides but distinct specialised polypeptides- a and ß, made up of seven alpha-helices each which played a crucial step in evolution of PBPs. PBPs carry out various light dependent responses such as complementary chromatic adaptation. The aim of this review is to summarize and discuss the recent progress in this field and to highlight the new and the questions that remain unresolved. PMID:26417362

  19. The Evolution of Sulfide Tolerance in the Cyanobacteria

    NASA Technical Reports Server (NTRS)

    Miller, Scott R.; Bebout, Brad M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Understanding how the function of extant microorganisms has recorded both their evolutionary histories and their past interactions with the environment is a stated goal of astrobiology. We are taking a multidisciplinary approach to investigate the diversification of sulfide tolerance mechanisms in the cyanobacteria, which vary both in their degree of exposure to sulfide and in their capacity to tolerate this inhibitor of photosynthetic electron transport. Since conditions were very reducing during the first part of Earth's history and detrital sulfides have been found in Archean sediments, mechanisms conferring sulfide tolerance may have been important for the evolutionary success of the ancestors of extant cyanobacteria. Two tolerance mechanisms have been identified in this group: (1) resistance of photosystem II, the principal target of sulfide toxicity; and (2) maintenance of the ability to fix carbon despite photosystem II inhibition by utilizing sulfide as an electron donor in photosystem I - dependent, anoxygenic photosynthesis. We are presently collecting comparative data on aspects of sulfide physiology for laboratory clones isolated from a variety of habitats. These data will be analyzed within a phylogenetic framework inferred from molecular sequence data collected for these clones to test how frequently different mechanisms of tolerance have evolved and which tolerance mechanism evolved first. In addition, by analyzing these physiological data together with environmental sulfide data collected from our research sites using microelectrodes, we can also test whether the breadth of an organism's sulfide tolerance can be predicted from the magnitude of variation in environmental sulfide concentration it has experienced in its recent evolutionary past and whether greater average sulfide concentration and/or temporal variability in sulfide favors the evolution of a particular mechanism of sulfide tolerance.

  20. Iron-Tolerant Cyanobacteria for Human Habitation beyond Earth

    NASA Technical Reports Server (NTRS)

    Brown, Igor; Sarkisova, Svetlana; Jones, Jeff; Sternberg, Paul; Bayless, David; Mckay, David S.

    2006-01-01

    In light of the President's Moon/Mars initiative, lunar exploration has once again become a priority for NASA. In order to establish permanent bases on the Moon and proceed with human exploration of Mars, two key problems will be addressed: first, the production of O2 and second, the production of methane (CH4). While O2 is required for life support systems (LSS), both liquid O2 and CH4 are needed as an oxidizer and a propellant, respectively for the Lunar Surface Access Module (LSAM) and the Crew Exploration Vehicle (CEV). Unlike previous propulsion systems, the new CEV will use liquid oxygen (LO2) as an oxidizer and liquid methane (LCH4) as a propellant. Existing technology (e.g. hydrogen reduction) for the production of liquid oxygen from lunar regolith is very energy intensive and requires high temperature reactors. We propose an alternative approach using iron-tolerant cyanobacteria. We have found that iron-tolerant cyanobacteria (IT CB) are capable of etching iron-bearing minerals, which may lead to bonds breaking between Fe and O of common lunar mare basalt Feoxides including ilmenite, pseudobrookite, ferropseudobrookite, and armalcolite with the subsequent release of both Fe, Ti and oxygen as by-products. We also propose to use CB biomass for CH4 production as carbon stock and a propellant. Both processes can be accomplished in an energy and cost effective manner because sunlight will be used as an energy source and allows the reactions at ambient temperatures between 10-60 C. Current evaluations include assessing the thermodynamics of such biogenic reactions using a variety of nutrients and atmospheric parameters, as well as assessing the rates and species variation effects of the driving reactions.

  1. Short-chain dehydrogenases/reductases in cyanobacteria.

    PubMed

    Kramm, Anneke; Kisiela, Michael; Schulz, Rüdiger; Maser, Edmund

    2012-03-01

    The short-chain dehydrogenases/reductases (SDRs) represent a large superfamily of enzymes, most of which are NAD(H)-dependent or NADP(H)-dependent oxidoreductases. They display a wide substrate spectrum, including steroids, alcohols, sugars, aromatic compounds, and xenobiotics. On the basis of characteristic sequence motifs, the SDRs are subdivided into two main (classical and extended) and three smaller (divergent, intermediate, and complex) families. Despite low residue identities in pairwise comparisons, the three-dimensional structure among the SDRs is conserved and shows a typical Rossmann fold. Here, we used a bioinformatics approach to determine whether and which SDRs are present in cyanobacteria, microorganisms that played an important role in our ecosystem as the first oxygen producers. Cyanobacterial SDRs could indeed be identified, and were clustered according to the SDR classification system. Furthermore, because of the early availability of its genome sequence and the easy application of transformation methods, Synechocystis sp. PCC 6803, one of the most important cyanobacterial strains, was chosen as the model organism for this phylum. Synechocystis sp. SDRs were further analysed with bioinformatics tools, such as hidden Markov models (HMMs). It became evident that several cyanobacterial SDRs show remarkable sequence identities with SDRs in other organisms. These so-called 'homologous' proteins exist in plants, model organisms such as Drosophila melanogaster and Caenorhabditis  elegans, and even in humans. As sequence identities of up to 60% were found between Synechocystis and humans, it was concluded that SDRs seemed to have been well conserved during evolution, even after dramatic terrestrial changes such as the conversion of the early reducing atmosphere to an oxidizing one by cyanobacteria. PMID:22251568

  2. Challenges for mapping cyanotoxin patterns from remote sensing of cyanobacteria

    USGS Publications Warehouse

    Stumpf, Rick P; Davis, Timothy W.; Wynne, Timothy T.; Graham, Jennifer; Loftin, Keith A.; Johengen, T.H.; Gossiaux, D.; Palladino, D.; Burtner, A.

    2016-01-01

    Using satellite imagery to quantify the spatial patterns of cyanobacterial toxins has several challenges. These challenges include the need for surrogate pigments – since cyanotoxins cannot be directly detected by remote sensing, the variability in the relationship between the pigments and cyanotoxins – especially microcystins (MC), and the lack of standardization of the various measurement methods. A dual-model strategy can provide an approach to address these challenges. One model uses either chlorophyll-a (Chl-a) or phycocyanin (PC) collected in situ as a surrogate to estimate the MC concentration. The other uses a remote sensing algorithm to estimate the concentration of the surrogate pigment. Where blooms are mixtures of cyanobacteria and eukaryotic algae, PC should be the preferred surrogate to Chl-a. Where cyanobacteria dominate, Chl-a is a better surrogate than PC for remote sensing. Phycocyanin is less sensitive to detection by optical remote sensing, it is less frequently measured, PC laboratory methods are still not standardized, and PC has greater intracellular variability. Either pigment should not be presumed to have a fixed relationship with MC for any water body. The MC-pigment relationship can be valid over weeks, but have considerable intra- and inter-annual variability due to changes in the amount of MC produced relative to cyanobacterial biomass. To detect pigments by satellite, three classes of algorithms (analytic, semi-analytic, and derivative) have been used. Analytical and semi-analytical algorithms are more sensitive but less robust than derivatives because they depend on accurate atmospheric correction; as a result derivatives are more commonly used. Derivatives can estimate Chl-a concentration, and research suggests they can detect and possibly quantify PC. Derivative algorithms, however, need to be standardized in order to evaluate the reproducibility of parameterizations between lakes. A strategy for producing useful estimates

  3. Estimation of cyanobacteria biovolume in water reservoirs by MERIS sensor.

    PubMed

    Medina-Cobo, M; Domínguez, J A; Quesada, A; de Hoyos, C

    2014-10-15

    Planktonic cyanobacteria primarily develop in lentic water bodies, such as lakes and water reservoirs. In certain instances, toxin-producing cyanobacterial populations might dominate the phytoplankton community. Satellite remote sensing is a useful tool for large spatial scale monitoring of cyanobacteria, and the MERIS sensor from the Envisat satellite has taken worldwide images at a high frequency for over 10 years. This short time lapse image collection has provided an extensive record of images for the analysis of variation in the cyanobacterial communities in water reservoirs for management and scientific purposes. The objective of this work is to determine the relationship between measured cyanobacterial biomass as biovolume and the estimations derived from MERIS imagery. This study encompasses two independent studies relying on data from 23 water reservoirs. First, a long-term global limnological research study was conducted that provided a field data collection that included cyanobacterial biovolume, among other variables. Second, a survey was conducted that applied the processed images derived from the Envisat MERIS sensor. The chlorophyll-a (Chl a) content and phycocyanin concentration (PC) were estimated from the MERIS images. The PC estimated by remote sensing and total cyanobacterial biovolume measured from the field samples were found to be significantly correlated (R(2) = 0.6219; p < 0.001). No relevant differences were found among the taxonomical groups, which indicated that this tool provides accurate estimations irrespective of the cyanobacterial group. For validation, the algorithm derived from the entire dataset was applied to the MERIS image dataset of the Rosarito reservoir. An estimated cyanobacterial biovolume time series was performed and compared to the biovolume data collected in an extensive sampling schedule spanning 4 years. The results indicated a strong correlation (R(2) = 0.72; p < 0.001) between the measured and estimated

  4. Using human urine as food for cyanobacteria in LSS

    NASA Astrophysics Data System (ADS)

    Kalacheva, Galina; Gribovskaya, Iliada; Kolmakova, Angela

    In biological LSS: human, higher plants, algae, united by common cycle of matter, native human urine is the most problematic substance for using in inter-link exchange. It contains urea, ammonium compounds and up to 10 g/l of NaCl. Each of the mentioned components is toxic for growing higher plants. As for inferior plants, experiments showed that cyanobacteria of genus Spirulina platensis and similar genus Oscillatoria deflexa can grow at NaCl concentrations up to 20 g/l and NH4Cl concentrations up to 800 mg/l. These cyanobacteria can be used in LSS as a photosynthesizing link. Besides, S. platensis is edible for humans and fish. To use urine as food for algae, it is necessary to remove urea and organics. All previously used methods for urine treatment aimed at urea destruction: heating to 300oC, ultraviolet exposure, freezing, oxidation on reactor with hydrogen peroxide, had no effect. We used the following method of urine treatment: urine evaporation till dry residue, subsequent combustion in muffle furnace at 450-500oC and creation of ash water extract of the same volume as the initial urine. Comparison of standard Zarrouk's solution for S. platensis and O. deflexa with the water extract of urine ash showed that the concentrations of K, Ca, Mg, P, S were similar. Successful experiments were made with O. deflexa that were grown on nutrient solution made of the water extract of urine ash with 10 g/l of NaHCO3 and 2 g/l of NaNO3. The sources of intersystem production of HCO3 and NO3 were shown, and the biochemical composition of the investigated algae species, including mineral composition, protein, carbohydrate, amino acid, lipid and vitamin content were studied.

  5. Phylogenetic analysis and molecular signatures defining a monophyletic clade of heterocystous cyanobacteria and identifying its closest relatives.

    PubMed

    Howard-Azzeh, Mohammad; Shamseer, Larissa; Schellhorn, Herb E; Gupta, Radhey S

    2014-11-01

    Detailed phylogenetic and comparative genomic analyses are reported on 140 genome sequenced cyanobacteria with the main focus on the heterocyst-differentiating cyanobacteria. In a phylogenetic tree for cyanobacteria based upon concatenated sequences for 32 conserved proteins, the available cyanobacteria formed 8-9 strongly supported clades at the highest level, which may correspond to the higher taxonomic clades of this phylum. One of these clades contained all heterocystous cyanobacteria; within this clade, the members exhibiting either true (Nostocales) or false (Stigonematales) branching of filaments were intermixed indicating that the division of the heterocysts-forming cyanobacteria into these two groups is not supported by phylogenetic considerations. However, in both the protein tree as well as in the 16S rRNA gene tree, the akinete-forming heterocystous cyanobacteria formed a distinct clade. Within this clade, the members which differentiate into hormogonia or those which lack this ability were also separated into distinct groups. A novel molecular signature identified in this work that is uniquely shared by the akinete-forming heterocystous cyanobacteria provides further evidence that the members of this group are specifically related and they shared a common ancestor exclusive of the other cyanobacteria. Detailed comparative analyses on protein sequences from the genomes of heterocystous cyanobacteria reported here have also identified eight conserved signature indels (CSIs) in proteins involved in a broad range of functions, and three conserved signature proteins, that are either uniquely or mainly found in all heterocysts-forming cyanobacteria, but generally not found in other cyanobacteria. These molecular markers provide novel means for the identification of heterocystous cyanobacteria, and they provide evidence of their monophyletic origin. Additionally, this work has also identified seven CSIs in other proteins which in addition to the heterocystous

  6. Phylogenetic analysis and molecular signatures defining a monophyletic clade of heterocystous cyanobacteria and identifying its closest relatives.

    PubMed

    Howard-Azzeh, Mohammad; Shamseer, Larissa; Schellhorn, Herb E; Gupta, Radhey S

    2014-11-01

    Detailed phylogenetic and comparative genomic analyses are reported on 140 genome sequenced cyanobacteria with the main focus on the heterocyst-differentiating cyanobacteria. In a phylogenetic tree for cyanobacteria based upon concatenated sequences for 32 conserved proteins, the available cyanobacteria formed 8-9 strongly supported clades at the highest level, which may correspond to the higher taxonomic clades of this phylum. One of these clades contained all heterocystous cyanobacteria; within this clade, the members exhibiting either true (Nostocales) or false (Stigonematales) branching of filaments were intermixed indicating that the division of the heterocysts-forming cyanobacteria into these two groups is not supported by phylogenetic considerations. However, in both the protein tree as well as in the 16S rRNA gene tree, the akinete-forming heterocystous cyanobacteria formed a distinct clade. Within this clade, the members which differentiate into hormogonia or those which lack this ability were also separated into distinct groups. A novel molecular signature identified in this work that is uniquely shared by the akinete-forming heterocystous cyanobacteria provides further evidence that the members of this group are specifically related and they shared a common ancestor exclusive of the other cyanobacteria. Detailed comparative analyses on protein sequences from the genomes of heterocystous cyanobacteria reported here have also identified eight conserved signature indels (CSIs) in proteins involved in a broad range of functions, and three conserved signature proteins, that are either uniquely or mainly found in all heterocysts-forming cyanobacteria, but generally not found in other cyanobacteria. These molecular markers provide novel means for the identification of heterocystous cyanobacteria, and they provide evidence of their monophyletic origin. Additionally, this work has also identified seven CSIs in other proteins which in addition to the heterocystous

  7. Excavating abiotic stress-related gene resources of terrestrial macroscopic cyanobacteria for crop genetic engineering: dawn and challenge

    PubMed Central

    Ye, Shuifeng; Gao, Xiang

    2015-01-01

    Genetically engineered (GE) crops with resistance to environmental stresses are one of the most important solutions for future food security. Numerous genes associated to plant stress resistance have been identified and characterized. However, the current reality is that only a few transgenic crops expressing prokaryotic genes are successfully applied in field conditions. These few prokaryotic genes include Agrobacterium strain CP4 EPSPS gene, Bacillus thuringiensis Cry1Ab gene and a bacterial chaperonin gene. Thus, the excavation of potentially critical genes still remains an arduous task for crop engineering. Terrestrial macroscopic cyanobacteria, Nostoc commune and Nostoc flagelliforme, which exhibit extreme resistance to desiccation stress, may serve as new prokaryotic bioresources for excavating critical genes. Recently, their marker gene wspA was heterologously expressed in Arabidopsis plant and the transgenics exhibited more flourishing root systems than wild-type plants under osmotic stress condition. In addition, some new genes associated with drought response and adaptation in N. flagelliforme are being uncovered by our ongoing RNA-seq analysis. Although the relevant work about the terrestrial macroscopic cyanobacteria is still underway, we believe that the prospect of excavating their critical genes for application in GE crops is quite optimistic. PMID:26418632

  8. Bryophyte-cyanobacteria associations as regulators of the northern latitude carbon balance in response to global change.

    PubMed

    Lindo, Zoë; Nilsson, Marie-Charlotte; Gundale, Michael J

    2013-07-01

    Ecosystems in the far north, including arctic and boreal biomes, are a globally significant pool of carbon (C). Global change is proposed to influence both C uptake and release in these ecosystems, thereby potentially affecting whether they act as C sources or sinks. Bryophytes (i.e., mosses) serve a variety of key functions in these systems, including their association with nitrogen (N2 )-fixing cyanobacteria, as thermal insulators of the soil, and producers of recalcitrant litter, which have implications for both net primary productivity (NPP) and heterotrophic respiration. While ground-cover bryophytes typically make up a small proportion of the total biomass in northern systems, their combined physical structure and N2 -fixing capabilities facilitate a disproportionally large impact on key processes that control ecosystem C and N cycles. As such, the response of bryophyte-cyanobacteria associations to global change may influence whether and how ecosystem C balances are influenced by global change. Here, we review what is known about their occurrence and N2 -fixing activity, and how bryophyte systems will respond to several key global change factors. We explore the implications these responses may have in determining how global change influences C balances in high northern latitudes.

  9. Fresh Water Cyanobacteria Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as an Anticancer Drug Resource

    PubMed Central

    Tiwari, Ratnakar; Srivastava, Vikas

    2015-01-01

    An increasing number of cancer patients worldwide, especially in third world countries, have raised concern to explore natural drug resources, such as the less explored fresh water filamentous cyanobacteria. Six strains of cyanobacteria (Phormidium sp. CCC727, Geitlerinema sp. CCC728, Arthrospira sp. CCC729, Phormidium sp. CCC731, Phormidium sp. CCC730, and Leptolyngbya sp. CCC732) were isolated (paddy fields and ponds in the Banaras Hindu University, campus) and five strains screened for anticancer potential using human colon adenocarcinoma (HT29) and human kidney adenocarcinoma (A498) cancer cell lines. Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 were the most potent as determined by examination of morphological features and by inhibition of growth by graded concentrations of crude extracts and thin-layer chromatography (TLC) eluates. Cell cycle analysis and multiplex assays using cancer biomarkers also confirmed Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as cancer drug resources. Apoptotic studies in the cells of A498 (cancer) and MCF-10A (normal human epithelial) exposed to crude extracts and TLC fractions revealed no significant impact on MCF-10A cells emphasizing its importance in the development of anticancer drug. Identification of biomolecules from these extracts are in progress. PMID:26325186

  10. Excavating abiotic stress-related gene resources of terrestrial macroscopic cyanobacteria for crop genetic engineering: dawn and challenge.

    PubMed

    Ye, Shuifeng; Gao, Xiang

    2015-01-01

    Genetically engineered (GE) crops with resistance to environmental stresses are one of the most important solutions for future food security. Numerous genes associated to plant stress resistance have been identified and characterized. However, the current reality is that only a few transgenic crops expressing prokaryotic genes are successfully applied in field conditions. These few prokaryotic genes include Agrobacterium strain CP4 EPSPS gene, Bacillus thuringiensis Cry1Ab gene and a bacterial chaperonin gene. Thus, the excavation of potentially critical genes still remains an arduous task for crop engineering. Terrestrial macroscopic cyanobacteria, Nostoc commune and Nostoc flagelliforme, which exhibit extreme resistance to desiccation stress, may serve as new prokaryotic bioresources for excavating critical genes. Recently, their marker gene wspA was heterologously expressed in Arabidopsis plant and the transgenics exhibited more flourishing root systems than wild-type plants under osmotic stress condition. In addition, some new genes associated with drought response and adaptation in N. flagelliforme are being uncovered by our ongoing RNA-seq analysis. Although the relevant work about the terrestrial macroscopic cyanobacteria is still underway, we believe that the prospect of excavating their critical genes for application in GE crops is quite optimistic. PMID:26418632

  11. The conifer biomarkers dehydroabietic and abietic acids are widespread in Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Costa, Maria Sofia; Rego, Adriana; Ramos, Vitor; Afonso, Tiago B.; Freitas, Sara; Preto, Marco; Lopes, Viviana; Vasconcelos, Vitor; Magalhães, Catarina; Leão, Pedro N.

    2016-03-01

    Terpenes, a large family of natural products with important applications, are commonly associated with plants and fungi. The diterpenoids dehydroabietic and abietic acids are defense metabolites abundant in resin, and are used as biomarkers for conifer plants. We report here for the first time that the two diterpenoid acids are produced by members of several genera of cyanobacteria. Dehydroabietic acid was isolated from two cyanobacterial strains and its identity was confirmed spectroscopically. One or both of the diterpenoids were detected in the cells of phylogenetically diverse cyanobacteria belonging to four cyanobacterial ‘botanical orders’, from marine, estuarine and inland environments. Dehydroabietic acid was additionally found in culture supernatants. We investigated the natural role of the two resin acids in cyanobacteria using ecologically-relevant bioassays and found that the compounds inhibited the growth of a small coccoid cyanobacterium. The unexpected discovery of dehydroabietic and abietic acids in a wide range of cyanobacteria has implications for their use as plant biomarkers.

  12. A state of the art of metabolic networks of unicellular microalgae and cyanobacteria for biofuel production.

    PubMed

    Baroukh, Caroline; Muñoz-Tamayo, Rafael; Steyer, Jean-Philippe; Bernard, Olivier

    2015-07-01

    The most promising and yet challenging application of microalgae and cyanobacteria is the production of renewable energy: biodiesel from microalgae triacylglycerols and bioethanol from cyanobacteria carbohydrates. A thorough understanding of microalgal and cyanobacterial metabolism is necessary to master and optimize biofuel production yields. To this end, systems biology and metabolic modeling have proven to be very efficient tools if supported by an accurate knowledge of the metabolic network. However, unlike heterotrophic microorganisms that utilize the same substrate for energy and as carbon source, microalgae and cyanobacteria require light for energy and inorganic carbon (CO2 or bicarbonate) as carbon source. This double specificity, together with the complex mechanisms of light capture, makes the representation of metabolic network nonstandard. Here, we review the existing metabolic networks of photoautotrophic microalgae and cyanobacteria. We highlight how these networks have been useful for gaining insight on photoautotrophic metabolism.

  13. Health effects associated with cyanobacteria exposure among beach attendees in Puerto Rico

    EPA Science Inventory

    Cyanobacteria and their toxins are associated with adverse human health effects, although among marine waters, the pyrrhophyta, including dinoflagellates are more recognized as health hazards. We recruited beach attendees during summer 2009, at Boquerón Beach, Puerto Rico...

  14. CURRENT ISSUES IN HTE DETECTION OF HUMAN EXPOSURE TO THE CYANOBACTERIA TOXINS, MICROCYSTINS

    EPA Science Inventory

    Introduction: Toxic cyanobacteria are contaminants of surface waters worldwide. Microcystins are some of the most commonly detected toxins. Biological evidence of human exposure has been difficult to obtain due to technical, temporal, and biological limitations. However, evide...

  15. The conifer biomarkers dehydroabietic and abietic acids are widespread in Cyanobacteria

    PubMed Central

    Costa, Maria Sofia; Rego, Adriana; Ramos, Vitor; Afonso, Tiago B.; Freitas, Sara; Preto, Marco; Lopes, Viviana; Vasconcelos, Vitor; Magalhães, Catarina; Leão, Pedro N.

    2016-01-01

    Terpenes, a large family of natural products with important applications, are commonly associated with plants and fungi. The diterpenoids dehydroabietic and abietic acids are defense metabolites abundant in resin, and are used as biomarkers for conifer plants. We report here for the first time that the two diterpenoid acids are produced by members of several genera of cyanobacteria. Dehydroabietic acid was isolated from two cyanobacterial strains and its identity was confirmed spectroscopically. One or both of the diterpenoids were detected in the cells of phylogenetically diverse cyanobacteria belonging to four cyanobacterial ‘botanical orders’, from marine, estuarine and inland environments. Dehydroabietic acid was additionally found in culture supernatants. We investigated the natural role of the two resin acids in cyanobacteria using ecologically-relevant bioassays and found that the compounds inhibited the growth of a small coccoid cyanobacterium. The unexpected discovery of dehydroabietic and abietic acids in a wide range of cyanobacteria has implications for their use as plant biomarkers. PMID:26996104

  16. Cyanobacteria blooms: Maya peoples between the politics of risk and the threat of disaster.

    PubMed

    Harvey, T S

    2012-01-01

    In October of 2009 an outbreak of cyanobacteria in Lake Atitlán, Guatemala gained international attention and global news coverage with interests coming from environmentalists, microbiologists, and local health agencies. A significantly less well-known aspect of the crisis was the perceptions and predicaments of Maya (indigenous) peoples for whom the lake is the primary source of life and livelihood. This research examines the communication of the public health risk of cyanobacteria to Maya peoples. Using an "ethnography of risk communication" approach, this work traces the circulation of the science of cyanobacteria and the construction of risk from government and public health translations through media transmissions to local Maya interpretations. The findings demonstrate how government and institutional translations (and media transmissions) of the science of cyanobacteria not only unwittingly produced misunderstandings about the health dangers but indirectly associated blame for the outbreak with indigenous peoples, calling into question their way of life.

  17. Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts.

    PubMed

    Canfora, Loredana; Vendramin, Elisa; Vittori Antisari, Livia; Lo Papa, Giuseppe; Dazzi, Carmelo; Benedetti, Anna; Iavazzo, Pietro; Adamo, Paola; Jungblut, Anne D; Pinzari, Flavia

    2016-06-01

    The interface between biological and geochemical components in the surface crust of a saline soil was investigated using X-ray diffraction, and variable pressure scanning electron microscopy in combination with energy dispersive X-ray spectrometry. Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of sulfur bacteria may had a physical control over the distinctive halite and gypsum structures produced. This suggests that cyanobacteria might directly or indirectly promote the formation of a protective envelope made of calcium and sulfur-based compounds. PMID:27090760

  18. The conifer biomarkers dehydroabietic and abietic acids are widespread in Cyanobacteria.

    PubMed

    Costa, Maria Sofia; Rego, Adriana; Ramos, Vitor; Afonso, Tiago B; Freitas, Sara; Preto, Marco; Lopes, Viviana; Vasconcelos, Vitor; Magalhães, Catarina; Leão, Pedro N

    2016-01-01

    Terpenes, a large family of natural products with important applications, are commonly associated with plants and fungi. The diterpenoids dehydroabietic and abietic acids are defense metabolites abundant in resin, and are used as biomarkers for conifer plants. We report here for the first time that the two diterpenoid acids are produced by members of several genera of cyanobacteria. Dehydroabietic acid was isolated from two cyanobacterial strains and its identity was confirmed spectroscopically. One or both of the diterpenoids were detected in the cells of phylogenetically diverse cyanobacteria belonging to four cyanobacterial 'botanical orders', from marine, estuarine and inland environments. Dehydroabietic acid was additionally found in culture supernatants. We investigated the natural role of the two resin acids in cyanobacteria using ecologically-relevant bioassays and found that the compounds inhibited the growth of a small coccoid cyanobacterium. The unexpected discovery of dehydroabietic and abietic acids in a wide range of cyanobacteria has implications for their use as plant biomarkers. PMID:26996104

  19. Cyanobacteria, Toxins and Indicators: Field Monitoring, Treatment Facility Monitoring and Treatment Studies

    EPA Science Inventory

    Cyanobacteria, formerly known as blue green algae, are an evolutionarily ancient and ubiquitous class of micro-organisms. Under a combination of conditions that include nutrient availability, warm temperatures, stagnant water and high solar irradiance, these organisms have the p...

  20. Dryland biological soil crust cyanobacteria show unexpected decreases in abundance under long-term elevated CO2.

    PubMed

    Steven, Blaire; Gallegos-Graves, La Verne; Yeager, Chris M; Belnap, Jayne; Evans, R David; Kuske, Cheryl R

    2012-12-01

    Biological soil crusts (biocrusts) cover soil surfaces in many drylands globally. The impacts of 10 years of elevated atmospheric CO2 on the cyanobacteria in biocrusts of an arid shrubland were examined at a large manipulated experiment in Nevada, USA. Cyanobacteria-specific quantitative PCR surveys of cyanobacteria small-subunit (SSU) rRNA genes suggested a reduction in biocrust cyanobacterial biomass in the elevated CO2 treatment relative to the ambient controls. Additionally, SSU rRNA gene libraries and shotgun metagenomes showed reduced representation of cyanobacteria in the total microbial community. Taxonomic composition of the cyanobacteria was similar under ambient and elevated CO2 conditions, indicating the decline was manifest across multiple cyanobacterial lineages. Recruitment of cyanobacteria sequences from replicate shotgun metagenomes to cyanobacterial genomes representing major biocrust orders also suggested decreased abundance of cyanobacteria sequences across the majority of genomes tested. Functional assignment of cyanobacteria-related shotgun metagenome sequences indicated that four subsystem categories, three related to oxidative stress, were differentially abundant in relation to the elevated CO2 treatment. Taken together, these results suggest that elevated CO2 affected a generalized decrease in cyanobacteria in the biocrusts and may have favoured cyanobacteria with altered gene inventories for coping with oxidative stress.

  1. Dryland biological soil crust cyanobacteria show unexpected decreases in abundance under long-term elevated CO2

    USGS Publications Warehouse

    Steven, Blaire; Gallegos-Graves, La Verne; Yeager, Chris M.; Belnap, Jayne; Evans, R. David; Kuske, Cheryl R.

    2012-01-01

    Biological soil crusts (biocrusts) cover soil surfaces in many drylands globally. The impacts of 10 years of elevated atmospheric CO2 on the cyanobacteria in biocrusts of an arid shrubland were examined at a large manipulated experiment in Nevada, USA. Cyanobacteria-specific quantitative PCR surveys of cyanobacteria small-subunit (SSU) rRNA genes suggested a reduction in biocrust cyanobacterial biomass in the elevated CO2 treatment relative to the ambient controls. Additionally, SSU rRNA gene libraries and shotgun metagenomes showed reduced representation of cyanobacteria in the total microbial community. Taxonomic composition of the cyanobacteria was similar under ambient and elevated CO2 conditions, indicating the decline was manifest across multiple cyanobacterial lineages. Recruitment of cyanobacteria sequences from replicate shotgun metagenomes to cyanobacterial genomes representing major biocrust orders also suggested decreased abundance of cyanobacteria sequences across the majority of genomes tested. Functional assignment of cyanobacteria-related shotgun metagenome sequences indicated that four subsystem categories, three related to oxidative stress, were differentially abundant in relation to the elevated CO2 treatment. Taken together, these results suggest that elevated CO2 affected a generalized decrease in cyanobacteria in the biocrusts and may have favoured cyanobacteria with altered gene inventories for coping with oxidative stress.

  2. Arsenic biotransformation by cyanobacteria from mining areas: evidences from culture experiments.

    PubMed

    Franco, Maione W; Ferreira, Fernanda A G; Vasconcelos, Igor F; Batista, Bruno L; Pujoni, Diego G F; Magalhães, Sérgia M S; Barbosa, Fernando; Barbosa, Francisco A R

    2015-12-01

    Elucidating the role of cyanobacteria in the biotransformation of arsenic (As) oxyanions is crucial to understand the biogeochemical cycle of this element and indicate species with potential for its bioremediation. In this study, we determined the EC50 for As(III) and As(V) and evaluated the biotransformation of As by Synechococcus sp. through high-performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and X-ray absorption fine structure spectroscopy (XAFS). Synechococcus sp. exhibited higher sensitivity to As(III) with an EC(50, 96 h) of 6.64 mg L(-1) that was approximately 400-fold lower than that for As(V). Even though the cells were exposed to concentrations of As(III) (6 mg L(-1)) approximately 67-fold lower than those of As(V) (400 mg L(-1)), similar intracellular concentrations of As (60.0 μg g(-1)) were observed after 30 days. As(V) was the predominant intracellular As species followed by As(III). Furthermore, organic As species such as monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) were observed in higher proportions after exposure to As(III). The differential toxicity among As oxyanions indicates that determining the redox state of As in the environment is fundamental to estimate toxicity risks to aquatic organisms. Synechococcus sp. demonstrated potential for its application in bioremediation due to the high accumulation of As and production of As organic compounds notably after exposure to As(III).

  3. Plasmid Conjugation from Proteobacteria as Evidence for the Origin of Xenologous Genes in Cyanobacteria

    PubMed Central

    Encinas, David; Garcillán-Barcia, M. Pilar; Santos-Merino, María; Delaye, Luis; Moya, Andrés

    2014-01-01

    Comparative genomics have shown that 5% of Synechococcus elongatus PCC 7942 genes are of probable proteobacterial origin. To investigate the role of interphylum conjugation in cyanobacterial gene acquisition, we tested the ability of a set of prototype proteobacterial conjugative plasmids (RP4, pKM101, R388, R64, and F) to transfer DNA from Escherichia coli to S. elongatus. A series of BioBrick-compatible, mobilizable shuttle vectors was developed. These vectors were based on the putative origin of replication of the Synechococcus resident plasmid pANL. Not only broad-host-range plasmids, such as RP4 and R388, but also narrower-host-range plasmids, such as pKM101, all encoding MPFT-type IV secretion systems, were able to transfer plasmid DNA from E. coli to S. elongatus by conjugation. Neither MPFF nor MPFI could be used as interphylum DNA delivery agents. Reciprocally, pANL-derived cointegrates could be introduced in E. coli by electroporation, where they conferred a functional phenotype. These results suggest the existence of potentially ample channels of gene flow between proteobacteria and cyanobacteria and point to MPFT-based interphylum conjugation as a potential mechanism to explain the proteobacterial origin of a majority of S. elongatus xenologous genes. PMID:24509315

  4. Effects of harmful cyanobacteria on the freshwater pathogenic free-living amoeba Acanthamoeba castellanii.

    PubMed

    Urrutia-Cordero, Pablo; Agha, Ramsy; Cirés, Samuel; Lezcano, María Ángeles; Sánchez-Contreras, María; Waara, Karl-Otto; Utkilen, Hans; Quesada, Antonio

    2013-04-15

    Grazing is a major regulating factor in cyanobacterial population dynamics and, subsequently, considerable effort has been spent on investigating the effects of cyanotoxins on major metazoan grazers. However, protozoan grazers such as free-living amoebae can also feed efficiently on cyanobacteria, while simultaneously posing a major threat for public health as parasites of humans and potential reservoirs of opportunistic pathogens. In this study, we conducted several experiments in which the freshwater amoeba Acanthamoeba castellanii was exposed to pure microcystin-LR (MC-LR) and six cyanobacterial strains, three MC-producing strains (MC-LR, MC-RR, MC-YR, MC-WR, [Dha7] MC-RR) and three strains containing other oligopeptides such as anabaenopeptins and cyanopeptolins. Although the exposure to high concentrations of pure MC-LR yielded no effects on amoeba, all MC-producing strains inflicted high mortality rates on amoeba populations, suggesting that toxic effects must be mediated through the ingestion of toxic cells. Interestingly, an anabaenopeptin-producing strain caused the greatest inhibition of amoeba growth, indicating that toxic bioactive compounds other than MCs are of great importance for amoebae grazers. Confocal scanning microscopy revealed different alterations in amoeba cytoskeleton integrity and as such, the observed declines in amoeba densities could have indeed been caused via a cascade of cellular events primarily triggered by oligopeptides with protein-phosphatase inhibition capabilities such as MCs or anabaenopeptins. Moreover, inducible-defense mechanisms such as the egestion of toxic, MC-producing cyanobacterial cells and the increase of resting stages (encystation) in amoebae co-cultivated with all cyanobacterial strains were observed in our experiments. Consequently, cyanobacterial strains showed different susceptibilities to amoeba grazing which were possibly influenced by the potentiality of their toxic secondary metabolites. Hence, this

  5. Prerequisite for highly efficient isoprenoid production by cyanobacteria discovered through the over-expression of 1-deoxy-d-xylulose 5-phosphate synthase and carbon allocation analysis.

    PubMed

    Kudoh, Kai; Kawano, Yusuke; Hotta, Shingo; Sekine, Midori; Watanabe, Takafumi; Ihara, Masaki

    2014-07-01

    Cyanobacteria have recently been receiving considerable attention owing to their potential as photosynthetic producers of biofuels and biomaterials. Here, we focused on the production of isoprenoids by cyanobacteria, and aimed to provide insight into metabolic engineering design. To this end, we examined the over-expression of a key enzyme in 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, 1-deoxy-d-xylulose 5-phosphate synthase (DXS) in the cyanobacterium Synechocystis sp. PCC6803. In the DXS-over-expression strain (Dxs_ox), the mRNA and protein levels of DXS were 4-times and 1.5-times the levels in the wild-type (WT) strain, respectively. The carotenoid content of the Dxs_ox strain (8.4 mg/g dry cell weight [DCW]) was also up to 1.5-times higher than that in the WT strain (5.6 mg/g DCW), whereas the glycogen content dramatically decreased to an undetectable level. These observations suggested that the carotenoid content in the Dxs_ox strain was increased by consuming glycogen, which is a C-storage compound in cyanobacteria. We also quantified the total sugar (145 and 104 mg/g DCW), total fatty acids (31 and 24 mg/g DCW) and total protein (200 and 240 mg/g DCW) content in the WT and Dxs_ox strains, respectively, which were much higher than the carotenoid content. In particular, approximately 54% of the proteins were phycobiliproteins. This study demonstrated the major destinations of carbon flux in cyanobacteria, and provided important insights into metabolic engineering. Target yield can be improved through optimization of gene expression, the DXS protein stabilization, cell propagation depression and restriction of storage compound synthesis.

  6. Accumulation and detoxication responses of the gastropod Lymnaea stagnalis to single and combined exposures to natural (cyanobacteria) and anthropogenic (the herbicide RoundUp(®) Flash) stressors.

    PubMed

    Lance, Emilie; Desprat, Julia; Holbech, Bente Frost; Gérard, Claudia; Bormans, Myriam; Lawton, Linda A; Edwards, Christine; Wiegand, Claudia

    2016-08-01

    Freshwater gastropods are increasingly exposed to multiple stressors in the field such as the herbicide glyphosate in Roundup formulations and cyanobacterial blooms either producing or not producing microcystins (MCs), potentially leading to interacting effects. Here, the responses of Lymnaea stagnalis to a 21-day exposure to non-MC or MC-producing (33μgL(-1)) Planktothrix agardhii alone or in combination with the commercial formulation RoundUp(®) Flash at a concentration of 1μgL(-1) glyphosate, followed by 14days of depuration, were studied via i) accumulation of free and bound MCs in tissues, and ii) activities of anti-oxidant (catalase CAT) and biotransformation (glutathione-S-transferase GST) enzymes. During the intoxication, the cyanobacterial exposure induced an early increase of CAT activity, independently of the MC content, probably related to the production of secondary cyanobacterial metabolites. The GST activity was induced by RoundUp(®) Flash alone or in combination with non MC-producing cyanobacteria, but was inhibited by MC-producing cyanobacteria with or without RoundUp(®) Flash. Moreover, MC accumulation in L. stagnalis was 3.2 times increased when snails were concomitantly exposed to MC-producing cyanobacteria with RoundUp(®), suggesting interacting effects of MCs on biotransformation processes. The potent inhibition of detoxication systems by MCs and RoundUp(®) Flash was reversible during the depuration, during which CAT and GST activities were significantly higher in snails previously exposed to MC-producing cyanobacteria with or without RoundUp(®) Flash than in other conditions, probably related to the oxidative stress caused by accumulated MCs remaining in tissues. PMID:27267390

  7. Accumulation and detoxication responses of the gastropod Lymnaea stagnalis to single and combined exposures to natural (cyanobacteria) and anthropogenic (the herbicide RoundUp(®) Flash) stressors.

    PubMed

    Lance, Emilie; Desprat, Julia; Holbech, Bente Frost; Gérard, Claudia; Bormans, Myriam; Lawton, Linda A; Edwards, Christine; Wiegand, Claudia

    2016-08-01

    Freshwater gastropods are increasingly exposed to multiple stressors in the field such as the herbicide glyphosate in Roundup formulations and cyanobacterial blooms either producing or not producing microcystins (MCs), potentially leading to interacting effects. Here, the responses of Lymnaea stagnalis to a 21-day exposure to non-MC or MC-producing (33μgL(-1)) Planktothrix agardhii alone or in combination with the commercial formulation RoundUp(®) Flash at a concentration of 1μgL(-1) glyphosate, followed by 14days of depuration, were studied via i) accumulation of free and bound MCs in tissues, and ii) activities of anti-oxidant (catalase CAT) and biotransformation (glutathione-S-transferase GST) enzymes. During the intoxication, the cyanobacterial exposure induced an early increase of CAT activity, independently of the MC content, probably related to the production of secondary cyanobacterial metabolites. The GST activity was induced by RoundUp(®) Flash alone or in combination with non MC-producing cyanobacteria, but was inhibited by MC-producing cyanobacteria with or without RoundUp(®) Flash. Moreover, MC accumulation in L. stagnalis was 3.2 times increased when snails were concomitantly exposed to MC-producing cyanobacteria with RoundUp(®), suggesting interacting effects of MCs on biotransformation processes. The potent inhibition of detoxication systems by MCs and RoundUp(®) Flash was reversible during the depuration, during which CAT and GST activities were significantly higher in snails previously exposed to MC-producing cyanobacteria with or without RoundUp(®) Flash than in other conditions, probably related to the oxidative stress caused by accumulated MCs remaining in tissues.

  8. Moss-cyanobacteria associations as biogenic sources of nitrogen in boreal forest ecosystems

    PubMed Central

    Rousk, Kathrin; Jones, Davey L.; DeLuca, Thomas H.

    2013-01-01

    The biological fixation of atmospheric nitrogen (N) is a major pathway for available N entering ecosystems. In N-limited boreal forests, a significant amount of N2 is fixed by cyanobacteria living in association with mosses, contributing up to 50% to the total N input. In this review, we synthesize reports on the drivers of N2 fixation in feather moss-cyanobacteria associations to gain a deeper understanding of their role for ecosystem-N-cycling. Nitrogen fixation in moss-cyanobacteria associations is inhibited by N inputs and therefore, significant fixation occurs only in low N-deposition areas. While it has been shown that artificial N additions in the laboratory as well as in the field inhibit N2 fixation in moss-cyanobacteria associations, the type, as well as the amounts of N that enters the system, affect N2 fixation differently. Another major driver of N2 fixation is the moisture status of the cyanobacteria-hosting moss, wherein moist conditions promote N2 fixation. Mosses experience large fluctuations in their hydrological status, undergoing significant natural drying and rewetting cycles over the course of only a few hours, especially in summer, which likely compromises the N input to the system via N2 fixation. Perhaps the most central question, however, that remains unanswered is the fate of the fixed N2 in mosses. The cyanobacteria are likely to leak N, but whether this N is transferred to the soil and if so, at which rates and timescales, is unknown. Despite our increasing understanding of the drivers of N2 fixation, the role moss-cyanobacteria associations play in ecosystem-N-cycling remains unresolved. Further, the relationship mosses and cyanobacteria share is unknown to date and warrants further investigation. PMID:23785359

  9. The effect of temperature on the sensitivity of Daphnia magna to cyanobacteria is genus dependent.

    PubMed

    Hochmuth, Jennifer D; De Schamphelaere, Karel A C

    2014-10-01

    In the present study, the authors investigated the effects of 6 different genera of cyanobacteria on multiple endpoints of Daphnia magna in a 21-d life table experiment conducted at 3 different temperatures (15 °C, 19 °C, and 23 °C). The specific aims were to test if the effect of temperature on Daphnia's sensitivity to cyanobacteria differed among different cyanobacteria and if the rank order from most to least harmful cyanobacteria to Daphnia reproduction changed or remained the same across the studied temperature range. Overall, the authors observed a decrease in harmful effects on reproduction with increasing temperature for Microcystis, Nodularia, and Aphanizomenon, and an increase in harmful effects with increasing temperature for Anabaena and Oscillatoria. No effect of temperature was observed on Daphnia sensitivity to Cylindrospermopsis. Harmful effects of Microcystis and Nodularia on reproduction appear to be mirrored by a decrease in length. On the other hand, harmful effects of Anabaena, Aphanizomenon, and Oscillatoria on reproduction were correlated with a decrease in intrinsic rate of natural increase, which was matched by a later onset of reproduction in exposures to Oscillatoria. In addition, the results suggest that the cyanobacteria rank order of harmfulness may change with temperature. Higher temperatures may increase the sensitivity of D. magna to the presence of some cyanobacteria (Anabaena and Oscillatoria) in their diet, whereas the harmful effects of others (Microcystis, Nodularia, and Aphanizomenon) may be reduced by higher temperatures.

  10. Antibacterial Activity of Marine and Black Band Disease Cyanobacteria against Coral-Associated Bacteria

    PubMed Central

    Gantar, Miroslav; Kaczmarsky, Longin T.; Stanić, Dina; Miller, Aaron W.; Richardson, Laurie L.

    2011-01-01

    Black band disease (BBD) of corals is a cyanobacteria-dominated polymicrobial disease that contains diverse populations of heterotrophic bacteria. It is one of the most destructive of coral diseases and is found globally on tropical and sub-tropical reefs. We assessed ten strains of BBD cyanobacteria, and ten strains of cyanobacteria isolated from other marine sources, for their antibacterial effect on growth of heterotrophic bacteria isolated from BBD, from the surface mucopolysaccharide layer (SML) of healthy corals, and three known bacterial coral pathogens. Assays were conducted using two methods: co-cultivation of cyanobacterial and bacterial isolates, and exposure of test bacteria to (hydrophilic and lipophilic) cyanobacterial cell extracts. During co-cultivation, 15 of the 20 cyanobacterial strains tested had antibacterial activity against at least one of the test bacterial strains. Inhibition was significantly higher for BBD cyanobacteria when compared to other marine cyanobacteria. Lipophilic extracts were more active than co-cultivation (extracts of 18 of the 20 strains were active) while hydrophilic extracts had very limited activity. In some cases co-cultivation resulted in stimulation of BBD and SML bacterial growth. Our results suggest that BBD cyanobacteria are involved in structuring the complex polymicrobial BBD microbial community by production of antimicrobial compounds. PMID:22073011

  11. Multiple adaptations to polar and alpine environments within cyanobacteria: a phylogenomic and Bayesian approach

    PubMed Central

    Chrismas, Nathan A. M.; Anesio, Alexandre M.; Sánchez-Baracaldo, Patricia

    2015-01-01

    Cyanobacteria are major primary producers in the polar and alpine regions contributing significantly to nitrogen and carbon cycles in the cryosphere. Recent advancements in environmental sequencing techniques have revealed great molecular diversity of microorganisms in cold environments. However, there are no comprehensive phylogenetic analyses including the entire known diversity of cyanobacteria from these extreme environments. We present here a global phylogenetic analysis of cyanobacteria including an extensive dataset comprised of available small subunit (SSU) rRNA gene sequences of cyanobacteria from polar and high altitude environments. Furthermore, we used a large-scale multi-gene (135 proteins and 2 ribosomal RNAs) genome constraint including 57 cyanobacterial genomes. Our analyses produced the first phylogeny of cold cyanobacteria exhibiting robust deep branching relationships implementing a phylogenomic approach. We recovered several clades common to Arctic, Antarctic and alpine sites suggesting that the traits necessary for survival in the cold have been acquired by a range of different mechanisms in all major cyanobacteria lineages. Bayesian ancestral state reconstruction revealed that 20 clades each have common ancestors with high probabilities of being capable of surviving in cold environments. PMID:26528250

  12. Phylogenetic distribution of compatible solute synthesis genes support a freshwater origin for cyanobacteria.

    PubMed

    Blank, Carrine E

    2013-10-01

    Previous work using ancestral state reconstruction of habitat salinity preference proposed that the early cyanobacteria likely lived in a freshwater environment. The aim of this study was to test that hypothesis by performing phylogenetic analyses of the genes underlying salinity preferences in the cyanobacteria. Phylogenetic analysis of compatible solute genes shows that sucrose synthesis genes were likely ancestral in the cyanobacteria, and were also likely inherited during the cyanobacterial endosymbiosis and into the photosynthetic algae and land plants. In addition, the genes for the synthesis of compatible solutes that are necessary for survival in marine and hypersaline environments (such as glucosylglycerol, glucosylglycerate, and glycine betaine) were likely acquired independently high up (i.e., more recently) in the cyanobacterial tree. Because sucrose synthesis is strongly associated with growth in a low salinity environment, this independently supports a freshwater origin for the cyanobacteria. It is also consistent with geologic evidence showing that the early oceans were much warmer and saltier than modern oceans-sucrose synthesis alone would have been insufficient for early cyanobacteria to have colonized early Precambrian oceans that had a higher ionic strength. Indeed, the acquisition of an expanded set of new compatible solute genes may have enabled the historical colonization of marine and hypersaline environments by cyanobacteria, midway through their evolutionary history. PMID:27007313

  13. Evaluation of extracellular products and mutagenicity in cyanobacteria cultures separated from a eutrophic reservoir.

    PubMed

    Huang, Winn-Jung; Lai, Chun-Hsi; Cheng, Yung-Ling

    2007-05-15

    The algal extracellular products (ECPs) in three cultures of cyanobacteria species (Anabaena, Microcystis, and Oscillatoria) dominating the eutrophic reservoir populations and their toxins have been investigated in the present work. Using gas chromatography coupled with high-resolution electron-impact mass spectrometry (GC/EI-MS) and high performance anion-exchange chromatography (HPAEC) techniques, more than 20 compounds were found in the algal culture (including cells and filtrates) extracts. The main identified ECPs were classified to polysaccharides, hydrocarbons, and aldehydes. Odor causing substances such as trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-methylisoborneol (2-MIB)were also found in the algal cultures. The potential mutagenicity of the algal suspensions was also studied with the Ames test. The organic extracts of the algal suspension from the axenic cultures were mutagenicity in TA98 without S9 mix and in TA100 with and without S9 mix. The results indicate that the ECPs of three algae species dominating the eutrophic reservoir were mutagenic clearly in the bacterial test. PMID:17391736

  14. Imaging single cells in a beam of live cyanobacteria with an X-ray laser.

    PubMed

    van der Schot, Gijs; Svenda, Martin; Maia, Filipe R N C; Hantke, Max; DePonte, Daniel P; Seibert, M Marvin; Aquila, Andrew; Schulz, Joachim; Kirian, Richard; Liang, Mengning; Stellato, Francesco; Iwan, Bianca; Andreasson, Jakob; Timneanu, Nicusor; Westphal, Daniel; Almeida, F Nunes; Odic, Dusko; Hasse, Dirk; Carlsson, Gunilla H; Larsson, Daniel S D; Barty, Anton; Martin, Andrew V; Schorb, Sebastian; Bostedt, Christoph; Bozek, John D; Rolles, Daniel; Rudenko, Artem; Epp, Sascha; Foucar, Lutz; Rudek, Benedikt; Hartmann, Robert; Kimmel, Nils; Holl, Peter; Englert, Lars; Duane Loh, Ne-Te; Chapman, Henry N; Andersson, Inger; Hajdu, Janos; Ekeberg, Tomas

    2015-02-11

    There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios. We obtain two-dimensional projection images directly from the diffraction patterns, and present the results as synthetic X-ray Nomarski images calculated from the complex-valued reconstructions. We further demonstrate that it is possible to record diffraction data to nanometer resolution on live cells with X-ray lasers. Extension to sub-nanometer resolution is within reach, although improvements in pulse parameters and X-ray area detectors will be necessary to unlock this potential.

  15. Trophic State and Toxic Cyanobacteria Density in Optimization Modeling of Multi-Reservoir Water Resource Systems

    PubMed Central

    Sulis, Andrea; Buscarinu, Paola; Soru, Oriana; Sechi, Giovanni M.

    2014-01-01

    The definition of a synthetic index for classifying the quality of water bodies is a key aspect in integrated planning and management of water resource systems. In previous works [1,2], a water system optimization modeling approach that requires a single quality index for stored water in reservoirs has been applied to a complex multi-reservoir system. Considering the same modeling field, this paper presents an improved quality index estimated both on the basis of the overall trophic state of the water body and on the basis of the density values of the most potentially toxic Cyanobacteria. The implementation of the index into the optimization model makes it possible to reproduce the conditions limiting water use due to excessive nutrient enrichment in the water body and to the health hazard linked to toxic blooms. The analysis of an extended limnological database (1996–2012) in four reservoirs of the Flumendosa-Campidano system (Sardinia, Italy) provides useful insights into the strengths and limitations of the proposed synthetic index. PMID:24759172

  16. Selective inhibition of cancer cells' proliferation by compounds included in extracts from Baltic Sea cyanobacteria.

    PubMed

    Felczykowska, Agnieszka; Pawlik, Anna; Mazur-Marzec, Hanna; Toruńska-Sitarz, Anna; Narajczyk, Magdalena; Richert, Malwina; Węgrzyn, Grzegorz; Herman-Antosiewicz, Anna

    2015-12-15

    Cyanobacteria are a rich source of biologically active compounds used in pharmacology and biotechnology. Due to their high capacity of adaptation, which is reflected in the production of diverse metabolites, including toxins, these microorganisms are able to inhabit very different environments. In this work, water and ethanol extracts from 11 cyanobacterial strains derived from the Baltic Sea (Microcystis, Synechocystis, Leptolyngbya, Pseudanabaena, Lyngbya, Phormidium, Nodularia and Anabaena genera) were screened for anticancer activity. MCF-7 human breast cancer and HeLa cervical cancer cell lines, as well as HDFa normal human fibroblasts, were used. Three extracts derived from Pseudanabaena sp., Pseudanabaena cf. galeata and Microcystis aeruginosa revealed potent and selective antiproliferative activities against cancer cells. The mechanism of the anticancer activity was explored in MCF-7 cells, and was found to rely on the inhibition of the pro-survival Akt kinase and induction of cell death. The peptide profiles of selected cyanobacterial extracts were determined using LC-MS/MS, and classes of bioactive compounds that might be potentially responsible for the observed anticancer activities are presented.

  17. Functional Genomics of Novel Secondary Metabolites from Diverse Cyanobacteria Using Untargeted Metabolomics

    PubMed Central

    Baran, Richard; Ivanova, Natalia N.; Jose, Nick; Garcia-Pichel, Ferran; Kyrpides, Nikos C.; Gugger, Muriel; Northen, Trent R.

    2013-01-01

    Mass spectrometry-based metabolomics has become a powerful tool for the detection of metabolites in complex biological systems and for the identification of novel metabolites. We previously identified a number of unexpected metabolites in the cyanobacterium Synechococcus sp. PCC 7002, such as histidine betaine, its derivatives and several unusual oligosaccharides. To test for the presence of these compounds and to assess the diversity of small polar metabolites in other cyanobacteria, we profiled cell extracts of nine strains representing much of the morphological and evolutionary diversification of this phylum. Spectral features in raw metabolite profiles obtained by normal phase liquid chromatography coupled to mass spectrometry (MS) were manually curated so that chemical formulae of metabolites could be assigned. For putative identification, retention times and MS/MS spectra were cross-referenced with those of standards or available sprectral library records. Overall, we detected 264 distinct metabolites. These included indeed different betaines, oligosaccharides as well as additional unidentified metabolites with chemical formulae not present in databases of metabolism. Some of these metabolites were detected only in a single strain, but some were present in more than one. Genomic interrogation of the strains revealed that generally, presence of a given metabolite corresponded well with the presence of its biosynthetic genes, if known. Our results show the potential of combining metabolite profiling and genomics for the identification of novel biosynthetic genes. PMID:24084783

  18. Trophic state and toxic cyanobacteria density in optimization modeling of multi-reservoir water resource systems.

    PubMed

    Sulis, Andrea; Buscarinu, Paola; Soru, Oriana; Sechi, Giovanni M

    2014-04-01

    The definition of a synthetic index for classifying the quality of water bodies is a key aspect in integrated planning and management of water resource systems. In previous works [1,2], a water system optimization modeling approach that requires a single quality index for stored water in reservoirs has been applied to a complex multi-reservoir system. Considering the same modeling field, this paper presents an improved quality index estimated both on the basis of the overall trophic state of the water body and on the basis of the density values of the most potentially toxic Cyanobacteria. The implementation of the index into the optimization model makes it possible to reproduce the conditions limiting water use due to excessive nutrient enrichment in the water body and to the health hazard linked to toxic blooms. The analysis of an extended limnological database (1996-2012) in four reservoirs of the Flumendosa-Campidano system (Sardinia, Italy) provides useful insights into the strengths and limitations of the proposed synthetic index. PMID:24759172

  19. The Cyanobacteria Derived Toxin Beta-N-Methylamino-L-Alanine and Amyotrophic Lateral Sclerosis

    PubMed Central

    Banack, Sandra Anne; Caller, Tracie A.; Stommel, Elijah W.

    2010-01-01

    There is mounting evidence to suggest that environmental factors play a major role in the development of neurodegenerative diseases like ALS (Amyotrophic Lateral Sclerosis). The non-protein amino acid beta-N-methylamino-L-alanine (BMAA) was first associated with the high incidence of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) in Guam, and has been implicated as a potential environmental factor in ALS, Alzheimer’s disease, and other neurodegenerative diseases. BMAA has a number of toxic effects on motor neurons including direct agonist action on NMDA and AMPA receptors, induction of oxidative stress, and depletion of glutathione. As a non-protein amino acid, there is also the strong possibility that BMAA could cause intraneuronal protein misfolding, the hallmark of neurodegeneration. While an animal model for BMAA-induced ALS is lacking, there is substantial evidence to support a link between this toxin and ALS. The ramifications of discovering an environmental trigger for ALS are enormous. In this article, we discuss the history, ecology, pharmacology and clinical ramifications of this ubiquitous, cyanobacteria-derived toxin. PMID:22069578

  20. Improved Free Fatty Acid Production in Cyanobacteria with Synechococcus sp. PCC 7002 as Host

    PubMed Central

    Ruffing, Anne M.

    2014-01-01

    Microbial free fatty acids (FFAs) have been proposed as a potential feedstock for renewable energy. The ability to directly convert carbon dioxide into FFAs makes cyanobacteria ideal hosts for renewable FFA production. Previous metabolic engineering efforts using the cyanobacterial hosts Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have demonstrated this direct conversion of carbon dioxide into FFAs; however, FFA yields in these hosts are limited by the negative impact of FFA production on the host cell physiology. This work investigates the use of Synechococcus sp. PCC 7002 as a cyanobacterial host for FFA production. In comparison to S. elongatus PCC 7942, Synechococcus sp. PCC 7002 strains produced and excreted FFAs at similar concentrations but without the detrimental effects on host physiology. The enhanced tolerance to FFA production with Synechococcus sp. PCC 7002 was found to be temperature-dependent, with physiological effects such as reduced photosynthetic yield and decreased photosynthetic pigments observed at higher temperatures. Additional genetic manipulations were targeted for increased FFA production, including thioesterases and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Overexpression of non-native RuBisCO subunits (rbcLS) from a psbAI promoter resulted in more than a threefold increase in FFA production, with excreted FFA concentrations reaching >130 mg/L. This work illustrates the importance of host strain selection for cyanobacterial biofuel production and demonstrates that the FFA tolerance of Synechococcus sp. PCC 7002 can allow for high yields of excreted FFA. PMID:25152890

  1. Imaging single cells in a beam of live cyanobacteria with an X-ray laser.

    PubMed

    van der Schot, Gijs; Svenda, Martin; Maia, Filipe R N C; Hantke, Max; DePonte, Daniel P; Seibert, M Marvin; Aquila, Andrew; Schulz, Joachim; Kirian, Richard; Liang, Mengning; Stellato, Francesco; Iwan, Bianca; Andreasson, Jakob; Timneanu, Nicusor; Westphal, Daniel; Almeida, F Nunes; Odic, Dusko; Hasse, Dirk; Carlsson, Gunilla H; Larsson, Daniel S D; Barty, Anton; Martin, Andrew V; Schorb, Sebastian; Bostedt, Christoph; Bozek, John D; Rolles, Daniel; Rudenko, Artem; Epp, Sascha; Foucar, Lutz; Rudek, Benedikt; Hartmann, Robert; Kimmel, Nils; Holl, Peter; Englert, Lars; Duane Loh, Ne-Te; Chapman, Henry N; Andersson, Inger; Hajdu, Janos; Ekeberg, Tomas

    2015-01-01

    There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios. We obtain two-dimensional projection images directly from the diffraction patterns, and present the results as synthetic X-ray Nomarski images calculated from the complex-valued reconstructions. We further demonstrate that it is possible to record diffraction data to nanometer resolution on live cells with X-ray lasers. Extension to sub-nanometer resolution is within reach, although improvements in pulse parameters and X-ray area detectors will be necessary to unlock this potential. PMID:25669616

  2. Cyanobacteria in CELSS: Growth strategies for nutritional variation and nitrogen cycling

    NASA Technical Reports Server (NTRS)

    Fry, I. V.; Packer, L.

    1990-01-01

    Cyanobacteria (blue-green algae) are versatile organisms which are capable of adjusting their cellular levels of carbohydrate, protein, and lipid in response to changes in the environment. Under stress conditions there is an imbalance between nitrogen metabolism and carbohydrate/lipid synthesis. The lesion in nitrogen assimilation is at the level of transport: the stress condition diverts energy from the active accumulation of nitrate to the extrusion of salt, and probably inhibits a cold-labile ATP'ace in the case of cold shock. Both situations affect the bioenergetic status of the cell such that the nitrogenous precursors for protein synthesis are depleted. Dispite the inhibition of protein synthesis and growth, photosynthetic reductant generation is relatively unaffected. The high O2 reductant would normally lead to photo-oxidative damage of cellular components; however, the organism copes by channeling the 'excess' reductant into carbon storage products. The increase in glycogen (28 to 35 percent dry weight increase) and the elongation of lipid fatty acid side chains (2 to 5 percent dry weight increase) at the expense of protein synthesis (25 to 34 percent dry weight decrease) results in carbohydrate, lipid and protein ratios that are closer to those required in the human diet. In addition, the selection of nitrogen fixing mutants which excrete ammonium ions present an opportunity to tailor these micro-organisms to meet the specific need for a sub-system to reverse potential loss of fixed nitrogen material.

  3. Improved Free Fatty Acid Production in Cyanobacteria with Synechococcus sp. PCC 7002 as Host.

    PubMed

    Ruffing, Anne M

    2014-01-01

    Microbial free fatty acids (FFAs) have been proposed as a potential feedstock for renewable energy. The ability to directly convert carbon dioxide into FFAs makes cyanobacteria ideal hosts for renewable FFA production. Previous metabolic engineering efforts using the cyanobacterial hosts Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have demonstrated this direct conversion of carbon dioxide into FFAs; however, FFA yields in these hosts are limited by the negative impact of FFA production on the host cell physiology. This work investigates the use of Synechococcus sp. PCC 7002 as a cyanobacterial host for FFA production. In comparison to S. elongatus PCC 7942, Synechococcus sp. PCC 7002 strains produced and excreted FFAs at similar concentrations but without the detrimental effects on host physiology. The enhanced tolerance to FFA production with Synechococcus sp. PCC 7002 was found to be temperature-dependent, with physiological effects such as reduced photosynthetic yield and decreased photosynthetic pigments observed at higher temperatures. Additional genetic manipulations were targeted for increased FFA production, including thioesterases and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Overexpression of non-native RuBisCO subunits (rbcLS) from a psbAI promoter resulted in more than a threefold increase in FFA production, with excreted FFA concentrations reaching >130 mg/L. This work illustrates the importance of host strain selection for cyanobacterial biofuel production and demonstrates that the FFA tolerance of Synechococcus sp. PCC 7002 can allow for high yields of excreted FFA. PMID:25152890

  4. Imaging single cells in a beam of live cyanobacteria with an X-ray laser

    NASA Astrophysics Data System (ADS)

    van der Schot, Gijs; Svenda, Martin; Maia, Filipe R. N. C.; Hantke, Max; Deponte, Daniel P.; Seibert, M. Marvin; Aquila, Andrew; Schulz, Joachim; Kirian, Richard; Liang, Mengning; Stellato, Francesco; Iwan, Bianca; Andreasson, Jakob; Timneanu, Nicusor; Westphal, Daniel; Almeida, F. Nunes; Odic, Dusko; Hasse, Dirk; Carlsson, Gunilla H.; Larsson, Daniel S. D.; Barty, Anton; Martin, Andrew V.; Schorb, Sebastian; Bostedt, Christoph; Bozek, John D.; Rolles, Daniel; Rudenko, Artem; Epp, Sascha; Foucar, Lutz; Rudek, Benedikt; Hartmann, Robert; Kimmel, Nils; Holl, Peter; Englert, Lars; Duane Loh, Ne-Te; Chapman, Henry N.; Andersson, Inger; Hajdu, Janos; Ekeberg, Tomas

    2015-02-01

    There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios. We obtain two-dimensional projection images directly from the diffraction patterns, and present the results as synthetic X-ray Nomarski images calculated from the complex-valued reconstructions. We further demonstrate that it is possible to record diffraction data to nanometer resolution on live cells with X-ray lasers. Extension to sub-nanometer resolution is within reach, although improvements in pulse parameters and X-ray area detectors will be necessary to unlock this potential.

  5. Unicellular cyanobacteria fix N2 in the subtropical North Pacific Ocean.

    PubMed

    Zehr, J P; Waterbury, J B; Turner, P J; Montoya, J P; Omoregie, E; Steward, G F; Hansen, A; Karl, D M

    2001-08-01

    Fixed nitrogen (N) often limits the growth of organisms in terrestrial and aquatic biomes, and N availability has been important in controlling the CO2 balance of modern and ancient oceans. The fixation of atmospheric dinitrogen gas (N2) to ammonia is catalysed by nitrogenase and provides a fixed N for N-limited environments. The filamentous cyanobacterium Trichodesmium has been assumed to be the predominant oceanic N2-fixing microorganism since the discovery of N2 fixation in Trichodesmium in 1961 (ref. 6). Attention has recently focused on oceanic N2 fixation because nitrogen availability is generally limiting in many oceans, and attempts to constrain the global atmosphere-ocean fluxes of CO2 are based on basin-scale N balances. Biogeochemical studies and models have suggested that total N2-fixation rates may be substantially greater than previously believed but cannot be reconciled with observed Trichodesmium abundances. It is curious that there are so few known N2-fixing microorganisms in oligotrophic oceans when it is clearly ecologically advantageous. Here we show that there are unicellular cyanobacteria in the open ocean that are expressing nitrogenase, and are abundant enough to potentially have a significant role in N dynamics. PMID:11493920

  6. Study of carotenoids in cyanobacteria by Raman spectroscopy.

    PubMed

    de Oliveira, Vanessa End; Neves Miranda, Marcela A C; Soares, Maria Carolina Silva; Edwards, Howell G M; de Oliveira, Luiz Fernando Cappa

    2015-01-01

    Cyanobacteria have established dominant aquatic populations around the world, generally in aggressive environments and under severe stress conditions, e.g., intense solar radiation. Several marine strains make use of compounds such as the polyenic molecules for their damage protection justifying the range of colours observed for these species. The peridinin/chlorophyll-a/protein complex is an excellent example of essential structures used for self-prevention; their systems allow to them surviving under aggressive environments. In our simulations, few protective dyes are required to the initial specimen defense; this is an important data concern the synthetic priority in order to supply adequate damage protection. Raman measurements obtained with 1064 and 514.5 nm excitations for Cylindrospermopsis raciborskii and Microcystis aeruginosa strains shows bands assignable to the carotenoid peridinin. It was characterized by bands at 1940, 1650, 1515, 1449, 1185, 1155 and 1000 cm(-1) assigned to ν(C=C=C) (allenic vibration), ν(C=C/CO), ν(C=C), δ(C-H, C-18/19), δ(C-H), ν(C-C), and ρ(C-CH3), respectively. Recognition by Raman spectroscopy proved to be an important tool for preliminaries detections and characterization of polyene molecules in several algae, besides initiate an interesting discussion about their synthetic priority.

  7. Molecular mechanism for the operation of nitrogen control in cyanobacteria.

    PubMed Central

    Luque, I; Flores, E; Herrero, A

    1994-01-01

    In cyanobacteria, ammonium exerts a negative regulation of the expression of proteins involved in the assimilation of nitrogen sources alternative to ammonium. In Synechococcus, mRNA levels of genes encoding proteins for nitrate and ammonium assimilation were observed to be negatively regulated by ammonium, and ammonium-regulated transcription start points were identified for those genes. The NtcA protein is a positive regulator of genes subjected to nitrogen control by ammonium. Mutants lacking NtcA exhibited only basal mRNA levels of the regulated genes, even in the absence of ammonium, indicating that NtcA exerts its regulatory action by positively influencing mRNA levels of the nitrogen-regulated genes. NtcA was observed to bind directly to the promoters of nitrogen-regulated genes, and the palindromic DNA sequence GTAN8TAC was identified as a sequence signature for NtcA-target sites. The structure of the nitrogen-, NtcA-regulated promoters of Synechococcus was determined to be constituted by a -10, Pribnow-like box in the form TAN3T, and an NtcA-binding site that substituted for the canonical -35 box. Images PMID:8026471

  8. Halotaxis of cyanobacteria in an intertidal hypersaline microbial mat.

    PubMed

    Kohls, Katharina; Abed, Raeid M M; Polerecky, Lubos; Weber, Miriam; de Beer, Dirk

    2010-03-01

    An intertidal hypersaline cyanobacterial mat from Abu Dhabi (United Arab Emirates) exhibited a reversible change in its surface colour within several hours upon changes in salinity of the overlying water. The mat surface was orange-reddish at salinities above 15% and turned dark green at lower salinities. We investigated this phenomenon using a polyphasic approach that included denaturing gradient gel electrophoresis, microscopy, high-performance liquid chromatography, hyperspectral imaging, absorption spectroscopy, oxygen microsensor measurements and modelling of salinity dynamics. Filaments of Microcoleus chthonoplastes, identified based on 16S rRNA sequencing and morphology, were found to migrate up and down when salinity was decreased below or increased above 15%, respectively, causing the colour change of the mat uppermost layer. Migration occurred in light and in the dark, and could be induced by different salts, not only NaCl. The influence of salinity-dependent and independent physico-chemical parameters, such as water activity, oxygen solubility, H2S, gravity and light, was excluded, indicating that the observed migration was due to a direct response to salt stress. We propose to term this salinity-driven cyanobacterial migration as 'halotaxis', a process that might play a vital role in the survival of cyanobacteria in environments exposed to continuous salinity fluctuations such as intertidal flats.

  9. Optimization of an Atmospheric Carbon Source for Extremophile Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Beaubien, Courtney

    This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a carbon dioxide feeding device was designed, built, and tested. The results indicate how much resin should be used with a given volume of algae medium: approximately 500 grams of resin can feed 1% CO2 at about three liters per minute to a ten liter medium of the Galdieria sulphuraria 5587.1 strain for one hour (equivalent to about 0.1 grams of carbon dioxide per hour per seven grams of algae). Using the resin device, the algae grew within their normal growth range: 0.096 grams of ash-free dry weight per liter over a six hour period. Future applications in which the resin-to-algae process can be utilized are discussed.

  10. Raman imaging of the diverse states of the filamentous cyanobacteria

    NASA Astrophysics Data System (ADS)

    Ishihara, J.; Tachikawa, M.; Mochizuki, A.; Sako, Y.; Iwasaki, H.; Morita, S.

    2013-05-01

    The objective of our research was to predict cell fates of a multicellular system, accompanied by cellular differentiation. To fulfill this objective, we sought to distinguish the differentiated and undifferentiated cells of filamentous cyanobacteria (Anabaena sp. PCC 7120) using Raman imaging. This technique indicated Raman bands of the cellular system, in which several bands were assigned to vibrations of β-carotene and scytonemin. We applied principal component analysis (PCA) to the Raman spectra to determine the PC1 and PC2 loading plots and their scores. The data points obtained for heterocyst tended to converge along the bottom of the scatterplot whereas those for vegetative cells were more widely distributed in the PC plane. This indicates that the chemical compositions of a heterocyst were relatively stable. As vegetative cells are capable of proliferation or differentiation, they may transit and exist in several states including the pseudo-differentiated state. The results suggest that the chemical compositions of a vegetative cell fluctuated according to its cellular condition. In conclusion, the results of Raman imaging indicate that the diverse states of vegetative cells are localized in a specific state through differentiation.

  11. Cyanobacteria use micro-optics to sense light direction

    PubMed Central

    Schuergers, Nils; Lenn, Tchern; Kampmann, Ronald; Meissner, Markus V; Esteves, Tiago; Temerinac-Ott, Maja; Korvink, Jan G; Lowe, Alan R; Mullineaux, Conrad W; Wilde, Annegret

    2016-01-01

    Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. The unicellular cyanobacterium Synechocystis sp. PCC 6803 moves with Type IV pili and measures light intensity and color with a range of photoreceptors. Here, we show that individual Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye. DOI: http://dx.doi.org/10.7554/eLife.12620.001 PMID:26858197

  12. Diversity of chemotactic heterotrophic bacteria associated with arctic cyanobacteria.

    PubMed

    Prasad, Sathish; Pratibha, Mambatta Shankaranarayanan; Manasa, Poorna; Buddhi, Sailaja; Begum, Zareena; Shivaji, Sisinthy

    2013-01-01

    The abundance and diversity of chemotactic heterotrophic bacteria associated with Arctic cyanobacteria was determined. The viable numbers ranged between 10(4) and 10(6) cell g(-1) cyanobacterial biomass. A total of 112 morphotypes, representing 22 phylotypes based on their 16S rRNA sequence similarity were isolated from the samples. All the phylotypes were Gram-negative with affiliation to the proteobacterial and bacteroidetes divisions. Among the 22 phylotypes, 14 were chemotactic to glucose. Majority of the phylotypes were psychrotolerant showing growth up to 30 °C. Representatives of Alphaproteobacteria, the genus Flavobacterium and the gammaproteobacterial Alcanivorax sp, were psychrophilic with growth at or below 18 °C. A significant percentage of phylotypes were pigmented (~68 %), rich in unsaturated membrane fatty acids and tolerated pH values and NaCl concentrations between 5.0-8.0 and 0.15-1.0 M, respectively. The percentages of phylotypes producing extracellular cold-active enzymes at 4 °C were amylase (18.18 %), lipase and urease (45.45 %), caseinase (59.09 %) and gelatinase (31.8 %). PMID:23053490

  13. Regulation of CO2 Concentrating Mechanism in Cyanobacteria

    PubMed Central

    Burnap, Robert L.; Hagemann, Martin; Kaplan, Aaron

    2015-01-01

    In this chapter, we mainly focus on the acclimation of cyanobacteria to the changing ambient CO2 and discuss mechanisms of inorganic carbon (Ci) uptake, photorespiration, and the regulation among the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. The structural components for several of the transport and uptake mechanisms are described and the progress towards elucidating their regulation is discussed in the context of studies, which have documented metabolomic changes in response to changes in Ci availability. Genes for several of the transport and uptake mechanisms are regulated by transcriptional regulators that are in the LysR-transcriptional regulator family and are known to act in concert with small molecule effectors, which appear to be well-known metabolites. Signals that trigger changes in gene expression and enzyme activity correspond to specific “regulatory metabolites” whose concentrations depend on the ambient Ci availability. Finally, emerging evidence for an additional layer of regulatory complexity involving small non-coding RNAs is discussed. PMID:25636131

  14. [Bioinformatics studies on photosynthetic system genes in cyanobacteria and chloroplasts].

    PubMed

    Shi, Ding-Ji; Zhang, Chao; Li, Shi-Ming; Li, Ci-Shan; Zhang, Peng-Peng; Yang, Ming-Li

    2004-06-01

    This study compared homology of base sequences in genes encoding photosynthetic system proteins of cyanobacteria (Synechocystics sp. PCC6803, Nostoc sp. PCC7120) with these of chloroplasts (from Marchantia Polymorpha, Nicotiana tobacum, Oryza sativ, Euglena gracilis, Pinus thunbergii, Zea mays, Odentella sinesis, Cyanophora paradoxa, Porphyra purpurea and Arabidopsis thaliana) by BLAST method. While the gene sequence of Synechocystics sp. PCC6803 was considered as the criterion (100%) the homology of others were compared with it. Among the genes for photosystem I, psaC homology was the highest (90.14%) and the lowest was psaJ (52.24%). The highest ones were psbD (83.71%) for photosystem II, atpB (79.58%) for ATP synthase and petB (81.66%) for cytochrome b6/f complex. The lowest ones were psbN (49.70%) for photosystem II, atpF (26.69%) for ATP synthase and petA (55.27%) for cytochrome b6/f complex. Also, this paper discussed why the homology of gene sequences was the highest or the lowest. No report has been published and this bioinformatics research may provide some evidences for the origin and evolution of chloroplasts.

  15. Production of volatile organic compounds by cyanobacteria Synechococcus sp.

    NASA Astrophysics Data System (ADS)

    Hiraiwa, M.; Abe, M.; Hashimoto, S.

    2014-12-01

    Phytoplankton are known to produce volatile organic compounds (VOCs), which contribute to environmental problems such as global warming and decomposition of stratospheric ozone. For example, picophytoplankton, such as Prochlorococcus and Synechococcus, are distributed in freshwater and oceans worldwide, accounting for a large proportion of biomass and primary production in the open ocean. However, to date, little is known about the production of VOCs by picophytoplankton. In this study, VOCs production by cyanobacteria Synechococcus sp. (NIES-981) was investigated. Synechococcus sp. was obtained from the National Institute for Environmental Studies (NIES), Japan, and cultured at 24°C in autoclaved f/2-Si medium under 54 ± 3 µE m-2 s-1 (1 E = 1 mol of photons) with a 12-h light and 12-h dark cycle. VOCs concentrations were determined using a purge-and-trap gas chromatograph-mass spectrometer (Agilent 5973). The concentrations of chlorophyll a (Chl a) were also determined using a fluorometer (Turner TD-700). Bromomethane (CH3Br) and isoprene were produced by Synechococcus sp. Isoprene production was similar to those of other phytoplankton species reported earlier. Isoprene was produced when Chl a was increasing in the early stage of the incubation period (5-15 days of incubation time, exponential phase), but CH3Br was produced when Chl a was reduced in the late stage of the incubation period (30-40 days of incubation time, death phase).

  16. Monitoring bioavailable phosphorus in lotic systems: a polyphasic approach based on cyanobacteria.

    PubMed

    Muñoz-Martín, M Ángeles; Martínez-Rosell, Aitor; Perona, Elvira; Fernández-Piñas, Francisca; Mateo, Pilar

    2014-03-15

    Conventional assays to measure phosphorus in freshwater systems are sometimes not sufficient to quantify the actual bioavailable P for aquatic biota since some inorganic or organic P species may not be detected by chemical methods, and their bioavailability can be affected by a range of environmental factors. This situation could lead regulatory agencies to be unable to detect imminent ecosystem-degrading phenomena such as cyanobacterial blooms. It could also be an obstacle in studying the ecophysiological requirements of freshwater communities. P bioavailability in five rivers located in central Spain was analysed by a polyphasic approach (combinations of different marker types) based on cyanobacteria. This approach included a parallel study with the use of a self-luminescent P-cyanobacterial bioreporter based on a phosphatase alkaline promoter, determination of in situ alkaline phosphatase activities from cyanobacteria found at sampling sites, and the characterisation of cyanobacterial morphological features related to P bioavailability (hairs, polyphosphate granules and calyptras). An inverse relationship was found between values of bioavailable P, measured by the bioreporter and phosphatase activities. Cyanobacteria from sampling sites with low bioavailable P showed high phosphatase activity and vice versa, although some differences in values of this activity were observed in different cyanobacteria found at the same place, in relation to different growth strategies. Morphological characteristics associated with P limitation or P enrichment also varied between sampling locations. Cyanobacteria collected from sampling sites with reduced P bioavailability, measured by bioreporter and phosphatase activity, had a lower abundance of polyphosphate granules; those cyanobacteria capable of developing hairs or calyptras showed a greater abundance of these structures. Conversely, polyphosphate granules in cyanobacteria increased as P bioavailability increased as measured

  17. Bloom-forming cyanobacteria support copepod reproduction and development in the Baltic Sea.

    PubMed

    Hogfors, Hedvig; Motwani, Nisha H; Hajdu, Susanna; El-Shehawy, Rehab; Holmborn, Towe; Vehmaa, Anu; Engström-Öst, Jonna; Brutemark, Andreas; Gorokhova, Elena

    2014-01-01

    It is commonly accepted that summer cyanobacterial blooms cannot be efficiently utilized by grazers due to low nutritional quality and production of toxins; however the evidence for such effects in situ is often contradictory. Using field and experimental observations on Baltic copepods and bloom-forming diazotrophic filamentous cyanobacteria, we show that cyanobacteria may in fact support zooplankton production during summer. To highlight this side of zooplankton-cyanobacteria interactions, we conducted: (1) a field survey investigating linkages between cyanobacteria, reproduction and growth indices in the copepod Acartia tonsa; (2) an experiment testing relationships between ingestion of the cyanobacterium Nodularia spumigena (measured by molecular diet analysis) and organismal responses (oxidative balance, reproduction and development) in the copepod A. bifilosa; and (3) an analysis of long term (1999-2009) data testing relationships between cyanobacteria and growth indices in nauplii of the copepods, Acartia spp. and Eurytemora affinis, in a coastal area of the northern Baltic proper. In the field survey, N. spumigena had positive effects on copepod egg production and egg viability, effectively increasing their viable egg production. By contrast, Aphanizomenon sp. showed a negative relationship with egg viability yet no significant effect on the viable egg production. In the experiment, ingestion of N. spumigena mixed with green algae Brachiomonas submarina had significant positive effects on copepod oxidative balance, egg viability and development of early nauplial stages, whereas egg production was negatively affected. Finally, the long term data analysis identified cyanobacteria as a significant positive predictor for the nauplial growth in Acartia spp. and E. affinis. Taken together, these results suggest that bloom forming diazotrophic cyanobacteria contribute to feeding and reproduction of zooplankton during summer and create a favorable growth

  18. Microclimate and limits to photosynthesis in a diverse community of hypolithic cyanobacteria in northern Australia

    USGS Publications Warehouse

    Tracy, Christopher R.; Streten-Joyce, Claire; Dalton, Robert; Nussear, Kenneth E.; Gibb, Karen S.; Christian, Keith A.

    2010-01-01

    Hypolithic microbes, primarily cyanobacteria, inhabit the highly specialized microhabitats under translucent rocks in extreme environments. Here we report findings from hypolithic cyanobacteria found under three types of translucent rocks (quartz, prehnite, agate) in a semiarid region of tropical Australia. We investigated the photosynthetic responses of the cyanobacterial communities to light, temperature and moisture in the laboratory, and we measured the microclimatic variables of temperature and soil moisture under rocks in the field over an annual cycle. We also used molecular techniques to explore the diversity of hypolithic cyanobacteria in this community and their phylogenetic relationships within the context of hypolithic cyanobacteria from other continents. Based on the laboratory experiments, photosynthetic activity required a minimum soil moisture of 15% (by mass). Peak photosynthetic activity occurred between approximately 8°C and 42°C, though some photosynthesis occurred between −1°C and 51°C. Maximum photosynthesis rates also occurred at light levels of approximately 150–550 μmol m−2 s−1. We used the field microclimatic data in conjunction with these measurements of photosynthetic efficiency to estimate the amount of time the hypolithic cyanobacteria could be photosynthetically active in the field. Based on these data, we estimated that conditions were appropriate for photosynthetic activity for approximately 942 h (∼75 days) during the year. The hypolithic cyanobacteria community under quartz, prehnite and agate rocks was quite diverse both within and between rock types. We identified 115 operational taxonomic units (OTUs), with each rock hosting 8–24 OTUs. A third of the cyanobacteria OTUs from northern Australia grouped with Chroococcidiopsis, a genus that has been identified from hypolithic and endolithic communities from the Gobi, Mojave, Atacama and Antarctic deserts. Several OTUs identified from northern Australia have

  19. Microclimate and limits to photosynthesis in a diverse community of hypolithic cyanobacteria in northern Australia.

    PubMed

    Tracy, Christopher R; Streten-Joyce, Claire; Dalton, Robert; Nussear, Kenneth E; Gibb, Karen S; Christian, Keith A

    2010-03-01

    Hypolithic microbes, primarily cyanobacteria, inhabit the highly specialized microhabitats under translucent rocks in extreme environments. Here we report findings from hypolithic cyanobacteria found under three types of translucent rocks (quartz, prehnite, agate) in a semiarid region of tropical Australia. We investigated the photosynthetic responses of the cyanobacterial communities to light, temperature and moisture in the laboratory, and we measured the microclimatic variables of temperature and soil moisture under rocks in the field over an annual cycle. We also used molecular techniques to explore the diversity of hypolithic cyanobacteria in this community and their phylogenetic relationships within the context of hypolithic cyanobacteria from other continents. Based on the laboratory experiments, photosynthetic activity required a minimum soil moisture of 15% (by mass). Peak photosynthetic activity occurred between approximately 8 degrees C and 42 degrees C, though some photosynthesis occurred between -1 degrees C and 51 degrees C. Maximum photosynthesis rates also occurred at light levels of approximately 150-550 micromol m(-2) s(-1). We used the field microclimatic data in conjunction with these measurements of photosynthetic efficiency to estimate the amount of time the hypolithic cyanobacteria could be photosynthetically active in the field. Based on these data, we estimated that conditions were appropriate for photosynthetic activity for approximately 942 h (approximately 75 days) during the year. The hypolithic cyanobacteria community under quartz, prehnite and agate rocks was quite diverse both within and between rock types. We identified 115 operational taxonomic units (OTUs), with each rock hosting 8-24 OTUs. A third of the cyanobacteria OTUs from northern Australia grouped with Chroococcidiopsis, a genus that has been identified from hypolithic and endolithic communities from the Gobi, Mojave, Atacama and Antarctic deserts. Several OTUs identified

  20. Biodiversity of cyanobacteria and green algae on monuments in the Mediterranean Basin: an overview.

    PubMed

    Macedo, Maria Filomena; Miller, Ana Zélia; Dionísio, Amélia; Saiz-Jimenez, Cesareo

    2009-11-01

    The presence and deteriorating action of micro-organisms on monuments and stone works of art have received considerable attention in the last few years. Knowledge of the microbial populations living on stone materials is the starting point for successful conservation treatment and control. This paper reviews the literature on cyanobacteria and chlorophyta that cause deterioration of stone cultural heritage (outdoor monuments and stone works of art) in European countries of the Mediterranean Basin. Some 45 case studies from 32 scientific papers published between 1976 and 2009 were analysed. Six lithotypes were considered: marble, limestone, travertine, dolomite, sandstone and granite. A wide range of stone monuments in the Mediterranean Basin support considerable colonization of cyanobacteria and chlorophyta, showing notable biodiversity. About 172 taxa have been described by different authors, including 37 genera of cyanobacteria and 48 genera of chlorophyta. The most widespread and commonly reported taxa on the stone cultural heritage in the Mediterranean Basin are, among cyanobacteria, Gloeocapsa, Phormidium and Chroococcus and, among chlorophyta, Chlorella, Stichococcus and Chlorococcum. The results suggest that cyanobacteria and chlorophyta colonize a wide variety of substrata and that this is related primarily to the physical characteristics of the stone surface, microclimate and environmental conditions and secondarily to the lithotype. PMID:19778965

  1. Phylogenetic inferences reveal a large extent of novel biodiversity in chemically rich tropical marine cyanobacteria.

    PubMed

    Engene, Niclas; Gunasekera, Sarath P; Gerwick, William H; Paul, Valerie J

    2013-03-01

    Benthic marine cyanobacteria are known for their prolific biosynthetic capacities to produce structurally diverse secondary metabolites with biomedical application and their ability to form cyanobacterial harmful algal blooms. In an effort to provide taxonomic clarity to better guide future natural product drug discovery investigations and harmful algal bloom monitoring, this study investigated the taxonomy of tropical and subtropical natural product-producing marine cyanobacteria on the basis of their evolutionary relatedness. Our phylogenetic inferences of marine cyanobacterial strains responsible for over 100 bioactive secondary metabolites revealed an uneven taxonomic distribution, with a few groups being responsible for the vast majority of these molecules. Our data also suggest a high degree of novel biodiversity among natural product-producing strains that was previously overlooked by traditional morphology-based taxonomic approaches. This unrecognized biodiversity is primarily due to a lack of proper classification systems since the taxonomy of tropical and subtropical, benthic marine cyanobacteria has only recently been analyzed by phylogenetic methods. This evolutionary study provides a framework for a more robust classification system to better understand the taxonomy of tropical and subtropical marine cyanobacteria and the distribution of natural products in marine cyanobacteria.

  2. Discovery of a super-strong promoter enables efficient production of heterologous proteins in cyanobacteria.

    PubMed

    Zhou, Jie; Zhang, Haifeng; Meng, Hengkai; Zhu, Yan; Bao, Guanhui; Zhang, Yanping; Li, Yin; Ma, Yanhe

    2014-03-28

    Cyanobacteria are oxygenic photosynthetic prokaryotes that play important roles in the global carbon cycle. Recently, engineered cyanobacteria capable of producing various small molecules from CO2 have been developed. However, cyanobacteria are seldom considered as factories for producing proteins, mainly because of the lack of efficient strong promoters. Here, we report the discovery and verification of a super-strong promoter P(cpc560), which contains two predicted promoters and 14 predicted transcription factor binding sites (TFBSs). Using P(cpc560), functional proteins were produced at a level of up to 15% of total soluble protein in the cyanobacterium Synechocystis sp. 6803, a level comparable to that produced in Escherichia coli. We demonstrated that the presence of multiple TFBSs in P(cpc560) is crucial for its promoter strength. Genetically transformable cyanobacteria neither have endotoxins nor form inclusion bodies; therefore, P(cpc560) opens the possibility to use cyanobacteria as alternative hosts for producing heterogeneous proteins from CO2 and inorganic nutrients.

  3. Iron deficiency increases growth and nitrogen-fixation rates of phosphorus-deficient marine cyanobacteria.

    PubMed

    Garcia, Nathan S; Fu, Feixue; Sedwick, Peter N; Hutchins, David A

    2015-01-01

    Marine dinitrogen (N2)-fixing cyanobacteria have large impacts on global biogeochemistry as they fix carbon dioxide (CO2) and fertilize oligotrophic ocean waters with new nitrogen. Iron (Fe) and phosphorus (P) are the two most important limiting nutrients for marine biological N2 fixation, and their availabilities vary between major ocean basins and regions. A long-standing question concerns the ability of two globally dominant N2-fixing cyanobacteria, unicellular Crocosphaera and filamentous Trichodesmium, to maintain relatively high N2-fixation rates in these regimes where both Fe and P are typically scarce. We show that under P-deficient conditions, cultures of these two cyanobacteria are able to grow and fix N2 faster when Fe deficient than when Fe replete. In addition, growth affinities relative to P increase while minimum concentrations of P that support growth decrease at low Fe concentrations. In Crocosphaera, this effect is accompanied by a reduction in cell sizes and elemental quotas. Relatively high growth rates of these two biogeochemically critical cyanobacteria in low-P, low-Fe environments such as those that characterize much of the oligotrophic ocean challenge the common assumption that low Fe levels can have only negative effects on marine primary producers. The closely interdependent influence of Fe and P on N2-fixing cyanobacteria suggests that even subtle shifts in their supply ratio in the past, present and future oceans could have large consequences for global carbon and nitrogen cycles.

  4. Evolution of multicellularity coincided with increased diversification of cyanobacteria and the Great Oxidation Event.

    PubMed

    Schirrmeister, Bettina E; de Vos, Jurriaan M; Antonelli, Alexandre; Bagheri, Homayoun C

    2013-01-29

    Cyanobacteria are among the most diverse prokaryotic phyla, with morphotypes ranging from unicellular to multicellular filamentous forms, including those able to terminally (i.e., irreversibly) differentiate in form and function. It has been suggested that cyanobacteria raised oxygen levels in the atmosphere around 2.45-2.32 billion y ago during the Great Oxidation Event (GOE), hence dramatically changing life on the planet. However, little is known about the temporal evolution of cyanobacterial lineages, and possible interplay between the origin of multicellularity, diversification of cyanobacteria, and the rise of atmospheric oxygen. We estimated divergence times of extant cyanobacterial lineages under Bayesian relaxed clocks for a dataset of 16S rRNA sequences representing the entire known diversity of this phylum. We tested whether the evolution of multicellularity overlaps with the GOE, and whether multicellularity is associated with significant shifts in diversification rates in cyanobacteria. Our results indicate an origin of cyanobacteria before the rise of atmospheric oxygen. The evolution of multicellular forms coincides with the onset of the GOE and an increase in diversification rates. These results suggest that multicellularity could have played a key role in triggering cyanobacterial evolution around the GOE.

  5. Genome Engineering in Cyanobacteria: Where We Are and Where We Need To Go.

    PubMed

    Ramey, C Josh; Barón-Sola, Ángel; Aucoin, Hanna R; Boyle, Nanette R

    2015-11-20

    Genome engineering of cyanobacteria is a promising area of development in order to produce fuels, feedstocks, and value-added chemicals in a sustainable way. Unfortunately, the current state of genome engineering tools for cyanobacteria lags far behind those of model organisms such as Escherichia coli and Saccharomyces cerevisiae. In this review, we present the current state of synthetic biology tools for genome engineering efforts in the most widely used cyanobacteria strains and areas that need concerted research efforts to improve tool development. Cyanobacteria pose unique challenges to genome engineering efforts because their cellular biology differs significantly from other eubacteria; therefore, tools developed for other genera are not directly transferrable. Standardized parts, such as promoters and ribosome binding sites, which control gene expression, require characterization in cyanobacteria in order to have fully predictable results. The application of these tools to genome engineering efforts is also discussed; the ability to do genome-wide searching and to introduce multiple mutations simultaneously is an area that needs additional research in order to enable fast and efficient strain engineering.

  6. Deciphering the factors associated with the colonization of rice plants by cyanobacteria.

    PubMed

    Bidyarani, Ngangom; Prasanna, Radha; Chawla, Gautam; Babu, Santosh; Singh, Rajendra

    2015-04-01

    Cyanobacteria-rice plant interactions were analyzed using a hydroponics experiment. The activity of plant defense and pathogenesis-related enzymes, scanning electron microscopy, growth, nitrogen fixation (measured as ARA), and DNA fingerprinting assays proved useful in illustrating the nature of associations of cyanobacteria with rice plants. Microscopic analyses revealed the presence of short filaments and coiled masses of filaments of cyanobacteria near the epidermis and cortex of roots and shoot tissues. Among the six cyanobacterial strains employed, Calothrix sp. (RPC1), Anabaena laxa (RPAN8), and Anabaena azollae (C16) were the best performing strains, in terms of colonization in roots and stem. These strains also enhanced nitrogen fixation and stimulated the activity of plant defense/cell wall-degrading enzymes. A significantly high correlation was also recorded between the elicited plant enzymes, growth, and ARA. DNA fingerprinting using highly iterated palindromic sequences (HIP-TG) further helped in proving the establishment of inoculated organisms in the roots/shoots of rice plants. This study illustrated that the colonization of cyanobacteria in the plant tissues is facilitated by increased elicitation of plant enzymes, leading to improved plant growth, nutrient mobilization, and enhanced plant fitness. Such strains can be promising candidates for developing "cyanobacteria colonized-nitrogen-fixing rice plants" in the future.

  7. Adaptive and acclimative responses of cyanobacteria to far-red light.

    PubMed

    Gan, Fei; Bryant, Donald A

    2015-10-01

    Cyanobacteria use three major photosynthetic complexes, photosystem (PS) I, PS II and phycobilisomes, to harvest and convert sunlight into chemical energy. Until recently, it was generally thought that cyanobacteria only used light between 400 nm and 700 nm to perform photosynthesis. However, the discovery of chlorophyll (Chl) d in Acaryochloris marina and Chl f in Halomicronema hongdechloris showed that some cyanobacteria could utilize far-red light. The synthesis of Chl f (and Chl d) is part of an extensive acclimation process, far-red light photoacclimation (FaRLiP), which occurs in many cyanobacteria. Organisms performing FaRLiP contain a conserved set of 17 genes encoding paralogous subunits of the three major photosynthetic complexes. Far-red light photoacclimation leads to substantial remodelling of the photosynthetic apparatus and other changes in cellular metabolism through extensive changes in transcription. Far-red light photoacclimation appears to be controlled by a red/far-red photoreceptor, RfpA, as well as two response regulators (RfpB and RfpC), one of which is a DNA-binding protein. The remodelled photosynthetic complexes, including novel phycobiliproteins, absorb light above 700 nm and enable cells to grow in far-red light. A much simpler acclimation response, low-light photoacclimation (LoLiP), occurs in some cyanobacteria that contain the apcD4-apcB3-isiX cluster, which allows cells to grow under low light conditions.

  8. Biodiversity of cyanobacteria and green algae on monuments in the Mediterranean Basin: an overview.

    PubMed

    Macedo, Maria Filomena; Miller, Ana Zélia; Dionísio, Amélia; Saiz-Jimenez, Cesareo

    2009-11-01

    The presence and deteriorating action of micro-organisms on monuments and stone works of art have received considerable attention in the last few years. Knowledge of the microbial populations living on stone materials is the starting point for successful conservation treatment and control. This paper reviews the literature on cyanobacteria and chlorophyta that cause deterioration of stone cultural heritage (outdoor monuments and stone works of art) in European countries of the Mediterranean Basin. Some 45 case studies from 32 scientific papers published between 1976 and 2009 were analysed. Six lithotypes were considered: marble, limestone, travertine, dolomite, sandstone and granite. A wide range of stone monuments in the Mediterranean Basin support considerable colonization of cyanobacteria and chlorophyta, showing notable biodiversity. About 172 taxa have been described by different authors, including 37 genera of cyanobacteria and 48 genera of chlorophyta. The most widespread and commonly reported taxa on the stone cultural heritage in the Mediterranean Basin are, among cyanobacteria, Gloeocapsa, Phormidium and Chroococcus and, among chlorophyta, Chlorella, Stichococcus and Chlorococcum. The results suggest that cyanobacteria and chlorophyta colonize a wide variety of substrata and that this is related primarily to the physical characteristics of the stone surface, microclimate and environmental conditions and secondarily to the lithotype.

  9. Chlorophylls d and f and Their Role in Primary Photosynthetic Processes of Cyanobacteria.

    PubMed

    Allakhverdiev, S I; Kreslavski, V D; Zharmukhamedov, S K; Voloshin, R A; Korol'kova, D V; Tomo, T; Shen, J-R

    2016-03-01

    The finding of unique Chl d- and Chl f-containing cyanobacteria in the last decade was a discovery in the area of biology of oxygenic photosynthetic organisms. Chl b, Chl c, and Chl f are considered to be accessory pigments found in antennae systems of photosynthetic organisms. They absorb energy and transfer it to the photosynthetic reaction center (RC), but do not participate in electron transport by the photosynthetic electron transport chain. However, Chl d as well as Chl a can operate not only in the light-harvesting complex, but also in the photosynthetic RC. The long-wavelength (Qy) Chl d and Chl f absorption band is shifted to longer wavelength (to 750 nm) compared to Chl a, which suggests the possibility for oxygenic photosynthesis in this spectral range. Such expansion of the photosynthetically active light range is important for the survival of cyanobacteria when the intensity of light not exceeding 700 nm is attenuated due to absorption by Chl a and other pigments. At the same time, energy storage efficiency in photosystem 2 for cyanobacteria containing Chl d and Chl f is not lower than that of cyanobacteria containing Chl a. Despite great interest in these unique chlorophylls, many questions related to functioning of such pigments in primary photosynthetic processes are still not elucidated. This review describes the latest advances in the field of Chl d and Chl f research and their role in primary photosynthetic processes of cyanobacteria.

  10. Modeling Filamentous Cyanobacteria Reveals the Advantages of Long and Fast Trichomes for Optimizing Light Exposure

    PubMed Central

    Tamulonis, Carlos; Postma, Marten; Kaandorp, Jaap

    2011-01-01

    Cyanobacteria form a very large and diverse phylum of prokaryotes that perform oxygenic photosynthesis. Many species of cyanobacteria live colonially in long trichomes of hundreds to thousands of cells. Of the filamentous species, many are also motile, gliding along their long axis, and display photomovement, by which a trichome modulates its gliding according to the incident light. The latter has been found to play an important role in guiding the trichomes to optimal lighting conditions, which can either inhibit the cells if the incident light is too weak, or damage the cells if too strong. We have developed a computational model for gliding filamentous photophobic cyanobacteria that allows us to perform simulations on the scale of a Petri dish using over 105 individual trichomes. Using the model, we quantify the effectiveness of one commonly observed photomovement strategy—photophobic responses—in distributing large populations of trichomes optimally over a light field. The model predicts that the typical observed length and gliding speeds of filamentous cyanobacteria are optimal for the photophobic strategy. Therefore, our results suggest that not just photomovement but also the trichome shape itself improves the ability of the cyanobacteria to optimize their light exposure. PMID:21789215

  11. Modeling filamentous cyanobacteria reveals the advantages of long and fast trichomes for optimizing light exposure.

    PubMed

    Tamulonis, Carlos; Postma, Marten; Kaandorp, Jaap

    2011-01-01

    Cyanobacteria form a very large and diverse phylum of prokaryotes that perform oxygenic photosynthesis. Many species of cyanobacteria live colonially in long trichomes of hundreds to thousands of cells. Of the filamentous species, many are also motile, gliding along their long axis, and display photomovement, by which a trichome modulates its gliding according to the incident light. The latter has been found to play an important role in guiding the trichomes to optimal lighting conditions, which can either inhibit the cells if the incident light is too weak, or damage the cells if too strong. We have developed a computational model for gliding filamentous photophobic cyanobacteria that allows us to perform simulations on the scale of a Petri dish using over 10(5) individual trichomes. Using the model, we quantify the effectiveness of one commonly observed photomovement strategy--photophobic responses--in distributing large populations of trichomes optimally over a light field. The model predicts that the typical observed length and gliding speeds of filamentous cyanobacteria are optimal for the photophobic strategy. Therefore, our results suggest that not just photomovement but also the trichome shape itself improves the ability of the cyanobacteria to optimize their light exposure.

  12. Chlorophylls d and f and Their Role in Primary Photosynthetic Processes of Cyanobacteria.

    PubMed

    Allakhverdiev, S I; Kreslavski, V D; Zharmukhamedov, S K; Voloshin, R A; Korol'kova, D V; Tomo, T; Shen, J-R

    2016-03-01

    The finding of unique Chl d- and Chl f-containing cyanobacteria in the last decade was a discovery in the area of biology of oxygenic photosynthetic organisms. Chl b, Chl c, and Chl f are considered to be accessory pigments found in antennae systems of photosynthetic organisms. They absorb energy and transfer it to the photosynthetic reaction center (RC), but do not participate in electron transport by the photosynthetic electron transport chain. However, Chl d as well as Chl a can operate not only in the light-harvesting complex, but also in the photosynthetic RC. The long-wavelength (Qy) Chl d and Chl f absorption band is shifted to longer wavelength (to 750 nm) compared to Chl a, which suggests the possibility for oxygenic photosynthesis in this spectral range. Such expansion of the photosynthetically active light range is important for the survival of cyanobacteria when the intensity of light not exceeding 700 nm is attenuated due to absorption by Chl a and other pigments. At the same time, energy storage efficiency in photosystem 2 for cyanobacteria containing Chl d and Chl f is not lower than that of cyanobacteria containing Chl a. Despite great interest in these unique chlorophylls, many questions related to functioning of such pigments in primary photosynthetic processes are still not elucidated. This review describes the latest advances in the field of Chl d and Chl f research and their role in primary photosynthetic processes of cyanobacteria. PMID:27262189

  13. Evolution of multicellularity coincided with increased diversification of cyanobacteria and the Great Oxidation Event

    PubMed Central

    Schirrmeister, Bettina E.; de Vos, Jurriaan M.; Antonelli, Alexandre; Bagheri, Homayoun C.

    2013-01-01

    Cyanobacteria are among the most diverse prokaryotic phyla, with morphotypes ranging from unicellular to multicellular filamentous forms, including those able to terminally (i.e., irreversibly) differentiate in form and function. It has been suggested that cyanobacteria raised oxygen levels in the atmosphere around 2.45–2.32 billion y ago during the Great Oxidation Event (GOE), hence dramatically changing life on the planet. However, little is known about the temporal evolution of cyanobacterial lineages, and possible interplay between the origin of multicellularity, diversification of cyanobacteria, and the rise of atmospheric oxygen. We estimated divergence times of extant cyanobacterial lineages under Bayesian relaxed clocks for a dataset of 16S rRNA sequences representing the entire known diversity of this phylum. We tested whether the evolution of multicellularity overlaps with the GOE, and whether multicellularity is associated with significant shifts in diversification rates in cyanobacteria. Our results indicate an origin of cyanobacteria before the rise of atmospheric oxygen. The evolution of multicellular forms coincides with the onset of the GOE and an increase in diversification rates. These results suggest that multicellularity could have played a key role in triggering cyanobacterial evolution around the GOE. PMID:23319632

  14. Adaptive and acclimative responses of cyanobacteria to far-red light.

    PubMed

    Gan, Fei; Bryant, Donald A

    2015-10-01

    Cyanobacteria use three major photosynthetic complexes, photosystem (PS) I, PS II and phycobilisomes, to harvest and convert sunlight into chemical energy. Until recently, it was generally thought that cyanobacteria only used light between 400 nm and 700 nm to perform photosynthesis. However, the discovery of chlorophyll (Chl) d in Acaryochloris marina and Chl f in Halomicronema hongdechloris showed that some cyanobacteria could utilize far-red light. The synthesis of Chl f (and Chl d) is part of an extensive acclimation process, far-red light photoacclimation (FaRLiP), which occurs in many cyanobacteria. Organisms performing FaRLiP contain a conserved set of 17 genes encoding paralogous subunits of the three major photosynthetic complexes. Far-red light photoacclimation leads to substantial remodelling of the photosynthetic apparatus and other changes in cellular metabolism through extensive changes in transcription. Far-red light photoacclimation appears to be controlled by a red/far-red photoreceptor, RfpA, as well as two response regulators (RfpB and RfpC), one of which is a DNA-binding protein. The remodelled photosynthetic complexes, including novel phycobiliproteins, absorb light above 700 nm and enable cells to grow in far-red light. A much simpler acclimation response, low-light photoacclimation (LoLiP), occurs in some cyanobacteria that contain the apcD4-apcB3-isiX cluster, which allows cells to grow under low light conditions. PMID:26234306

  15. Heterocystous Cyanobacteria in Microbialites Play an Important Role in N2 Fixation and Carbonate Mineral Precipitation

    NASA Astrophysics Data System (ADS)

    Alcantara-Hernandez, R. J.

    2015-12-01

    Lake Alchichica is a maars type crater-lake located in Central Mexico (pH > 8.9, EC ~13.39 mS cm-1). This limnological system harbors two types of microbialites that can be found around the entire perimeter of the lake (Fig. 1). These structures are representative examples of complex and diverse microbiological assemblages, where microbial activity promotes lithification by trapping, binding and/or precipitating detrital or chemical sediments. Previous studies determined that the microbialites of Lake Alchichica fix N2 to thrive under the N-limiting conditions of the lake, and that these nitrogenase activity peaks are related to heterocystous cyanobacteria that couple photosynthesis to N2 fixation during daylight periods. Heterocystous cyanobacteria (Nostocales) together with Oscillatoriales (non-heterocystous filamentous cyanobacteria) and other cyanobacterial groups have been described as the most abundant cyanobacteria in Alchichica microbialites, and in lithifying mats. Our results suggest that heterocystous cyanobacteria play an important role not only by fixing N2 for biomass construction, but also because their heterocysts host in their external cell membranes main sites for carbonate mineral precipitation including calcium carbonates and siderite. Previous research has shown that the heterocyst is the specialized site for cellular respiration associated to the pH decrease of vegetative/photosynthetic cells, contributing thus to the precipitation of carbonates and the accretion of the organosedimentary structure

  16. Growth of cyanobacteria on Martian Regolith Simulant after exposure to vacuum

    NASA Astrophysics Data System (ADS)

    Arai, Mayumi; Sato, Seigo; Ohmori, Masayuki; Tomita-Yokotani, Kaori; Hashimoto, Hirofumi; Yamashita, Masamichi

    Habitation on Mars is one of our challenges in this century. The growth of cyanobacteria on Martian Regolith Simulant (MRS) was studied with two species of terrestrial cyanobacteria, Nostoc, and one species of other cyanobacterium, Synechosystis. Their vacuum tolerances was examined in order to judge feasibility of the use of cyanobacteria to creat habitable environment on a distant planet. The viability of cyanobacteria tested was evaluated by the microscopic observation after staining by FDA (fluorescein diacetate). A part of them were also re-incubated again in a liquid culture medium, and viability and the chlorophyll production were examined in detail. Nostoc was found to grow for over 140 days with their having normal function of chlorophyll synthesis on the MRS. After the exposure to high vacuum environment (10-5 Pa) for a year, Nostoc sp. started growth. Chlorophyll was produced after this vacuum exposure as well. The A'MED (Arai's Mars Ecosystem Dome, A'MED) is designed to install on Mars for conducting agricultural production in it. We performed the fundamental experiment with MRS. These results show a possibility that cyanobacteria could adapt to MRS, and grow under the low pressure environment expected on Mars.

  17. Iron deficiency increases growth and nitrogen-fixation rates of phosphorus-deficient marine cyanobacteria.

    PubMed

    Garcia, Nathan S; Fu, Feixue; Sedwick, Peter N; Hutchins, David A

    2015-01-01

    Marine dinitrogen (N2)-fixing cyanobacteria have large impacts on global biogeochemistry as they fix carbon dioxide (CO2) and fertilize oligotrophic ocean waters with new nitrogen. Iron (Fe) and phosphorus (P) are the two most important limiting nutrients for marine biological N2 fixation, and their availabilities vary between major ocean basins and regions. A long-standing question concerns the ability of two globally dominant N2-fixing cyanobacteria, unicellular Crocosphaera and filamentous Trichodesmium, to maintain relatively high N2-fixation rates in these regimes where both Fe and P are typically scarce. We show that under P-deficient conditions, cultures of these two cyanobacteria are able to grow and fix N2 faster when Fe deficient than when Fe replete. In addition, growth affinities relative to P increase while minimum concentrations of P that support growth decrease at low Fe concentrations. In Crocosphaera, this effect is accompanied by a reduction in cell sizes and elemental quotas. Relatively high growth rates of these two biogeochemically critical cyanobacteria in low-P, low-Fe environments such as those that characterize much of the oligotrophic ocean challenge the common assumption that low Fe levels can have only negative effects on marine primary producers. The closely interdependent influence of Fe and P on N2-fixing cyanobacteria suggests that even subtle shifts in their supply ratio in the past, present and future oceans could have large consequences for global carbon and nitrogen cycles. PMID:24972068

  18. Harmful freshwater algal blooms, with an emphasis on cyanobacteria.

    PubMed

    Paerl, H W; Fulton, R S; Moisander, P H; Dyble, J

    2001-04-01

    Suspended algae, or phytoplankton, are the prime source of organic matter supporting food webs in freshwater ecosystems. Phytoplankton productivity is reliant on adequate nutrient supplies; however, increasing rates of nutrient supply, much of it manmade, fuels ac