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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 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

  2. Optical detection of microcystin produced by cyanobacteria

    NASA Astrophysics Data System (ADS)

    Al-Ammar, R.; Nabok, A.; Hashim, A.; Smith, T.

    2013-06-01

    Microcystin (MC-LR) produced by cyanobacteria (blue-green algae) was detected in direct immunoassay with specific monoclonal antibody MC10E7 using an optical method of Total Internal Reflection Ellipsometry (TIRE). The minimal detected concentration of MC-LR of 0.1 ng/ml is a remarkable achievement for direct immunoassay against such low molecular weight analyte molecule. The study of binding kinetics of MC-LR to MC10E7 antibody allowed the evaluation of the association constant KA of about 108 (l/Mol) typical for highly specific immune reactions. Concentration of MC-LR in aqueous solutions was reduced using an absorbent made of polyelectrolyte-coated microparticles functionalized with MC10E7 antibodies.

  3. 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

  4. 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. PMID:25207941

  5. 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

  6. 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

  7. 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

  8. Temporal variations in microcystin-producing cells and microcystin concentrations in two fresh water ponds.

    PubMed

    Singh, Shweta; Rai, Pankaj Kumar; Chau, Rocky; Ravi, Alok Kumar; Neilan, Brett A; Asthana, Ravi Kumar

    2015-02-01

    The relationship between microcystin production, microcystin-producing cyanobacteria, including Microcystis spp., and various biological and physicochemical parameters in Sankuldhara and Lakshmikund, situated in the same geographical area was studied over a period of 1.5 years. Seasonal variation in cyanobacterial 16S rRNA, Microcystis spp. 16S rRNA, mcyA and mcyB genes were quantitatively determined by real-time PCR. Microcystis was the dominant microcystin producer in both study sites constituting 67% and 97% of the total microcystin-producing cyanobacteria at Sankuldhara and Lakshmikund, respectively. Microcystin concentrations were 2.19-39.60 μg/L and 15.22-128.14 μg/L at Sankuldhara and Lakshmikund, respectively, as determined by LC-MS. Principal component analysis revealed a strong positive correlation between microcystin concentration and the copy number of mcyA and mcyB, chlorophyll a and cyanobacterial biomass at both sites. The higher microcystin concentrations in Lakshmikund pond were attributed to the high copy number of mcy genes present coupled with the pond's eutrophication status, as indicated by high total algal biomass, high chlorophyll a content, high nutrient load and low DO. Therefore, a significant difference in microcystin concentrations, correlating with these various biological and physicochemical parameters, confirms the importance of local environmental variables in the overall regulation of microcystins production. PMID:25463934

  9. 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 ...

  10. 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

  11. 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

  12. Target gene approaches: Gene expression in Daphnia magna exposed to predator-borne kairomones or to microcystin-producing and microcystin-free Microcystis aeruginosa

    PubMed Central

    2009-01-01

    Background Two major biological stressors of freshwater zooplankton of the genus Daphnia are predation and fluctuations in food quality. Here we use kairomones released from a planktivorous fish (Leucaspius delineatus) and from an invertebrate predator (larvae of Chaoborus flavicans) to simulate predation pressure; a microcystin-producing culture of the cyanobacterium Microcystis aeruginosa and a microcystin-deficient mutant are used to investigate effects of low food quality. Real-time quantitative polymerase chain reaction (QPCR) allows quantification of the impact of biotic stressors on differential gene activity. The draft genome sequence for Daphnia pulex facilitates the use of candidate genes by precisely identifying orthologs to functionally characterized genes in other model species. This information is obtained by constructing phylogenetic trees of candidate genes with the knowledge that the Daphnia genome is composed of many expanded gene families. Results We evaluated seven candidate reference genes for QPCR in Daphnia magna after exposure to kairomones. As a robust approach, a combination normalisation factor (NF) was calculated based on the geometric mean of three of these seven reference genes: glyceraldehyde-3-phosphate dehydrogenase, TATA-box binding protein and succinate dehydrogenase. Using this NF, expression of the target genes actin and alpha-tubulin were revealed to be unchanged in the presence of the tested kairomones. The presence of fish kairomone up-regulated one gene (cyclophilin) involved in the folding of proteins, whereas Chaoborus kairomone down-regulated the same gene. We evaluated the same set of candidate reference genes for QPCR in Daphnia magna after exposure to a microcystin-producing and a microcystin-free strain of the cyanobacterium Microcystis aeruginosa. The NF was calculated based on the reference genes 18S ribosomal RNA, alpha-tubulin and TATA-box binding protein. We found glyceraldehyde-3-phosphate dehydrogenase and

  13. 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.

  14. Ammonium photo-production by heterocytous cyanobacteria: potentials and constraints.

    PubMed

    Grizeau, Dominique; Bui, Lan Anh; Dupré, Catherine; Legrand, Jack

    2016-08-01

    Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N2-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation. PMID:25613641

  15. 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

  16. 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.

  17. Potassium Salts Inhibit Growth of the Cyanobacteria Microcystis spp. in Pond Water and Defined Media: Implications for Control of Microcystin-Producing Aquatic Blooms

    PubMed Central

    Parker, D. L.; Kumar, H. D.; Rai, L. C.; Singh, J. B.

    1997-01-01

    Ten metals were assayed in 21 Indian ponds which comprised three groups: (i) eutrophic alkaline ponds containing <2.5 mM potassium and thick growths of Microcystis aeruginosa or Microcystis flos-aquae during most of the year, (ii) equally eutrophic alkaline ponds containing >2.8 mM potassium and no detectable Microcystis growth, and (iii) oligo- or mesotrophic ponds with various potassium and hydrogen ion concentrations and no persistent Microcystis blooms. The effects of potassium on Microcystis growth were examined in filter-sterilized pond water and in defined culture media. A 50% reduction in the 10-day yield of cultured M. aeruginosa was observed in DP medium and pond water supplemented with 1 and 3 mM KCl, respectively. In contrast, the addition of 2 to 30 mM NaCl did not suppress the growth of M. aeruginosa in either DP medium or pond water. Both 5 mM KCl and 20 mM KHCO(inf3) in J medium strongly inhibited the growth of M. flos-aquae C3-9, whereas 5 to 30 mM NaCl had no effect and 20 mM NaHCO(inf3) was stimulatory. For pond water cultured with a mixture of M. aeruginosa and the duckweed Wolffia arrhiza, M. aeruginosa dominated in unsupplemented water and W. arrhiza dominated in water supplemented with 4.8 mM KCl. Implications for the ecology and control of Microcystis blooms are discussed. PMID:16535629

  18. Potassium Salts Inhibit Growth of the Cyanobacteria Microcystis spp. in Pond Water and Defined Media: Implications for Control of Microcystin-Producing Aquatic Blooms.

    PubMed

    Parker, D L; Kumar, H D; Rai, L C; Singh, J B

    1997-06-01

    Ten metals were assayed in 21 Indian ponds which comprised three groups: (i) eutrophic alkaline ponds containing <2.5 mM potassium and thick growths of Microcystis aeruginosa or Microcystis flos-aquae during most of the year, (ii) equally eutrophic alkaline ponds containing >2.8 mM potassium and no detectable Microcystis growth, and (iii) oligo- or mesotrophic ponds with various potassium and hydrogen ion concentrations and no persistent Microcystis blooms. The effects of potassium on Microcystis growth were examined in filter-sterilized pond water and in defined culture media. A 50% reduction in the 10-day yield of cultured M. aeruginosa was observed in DP medium and pond water supplemented with 1 and 3 mM KCl, respectively. In contrast, the addition of 2 to 30 mM NaCl did not suppress the growth of M. aeruginosa in either DP medium or pond water. Both 5 mM KCl and 20 mM KHCO(inf3) in J medium strongly inhibited the growth of M. flos-aquae C3-9, whereas 5 to 30 mM NaCl had no effect and 20 mM NaHCO(inf3) was stimulatory. For pond water cultured with a mixture of M. aeruginosa and the duckweed Wolffia arrhiza, M. aeruginosa dominated in unsupplemented water and W. arrhiza dominated in water supplemented with 4.8 mM KCl. Implications for the ecology and control of Microcystis blooms are discussed. PMID:16535629

  19. 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. PMID:25662238

  20. 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

  1. 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

  2. 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

    2014-11-01

    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

  3. 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

  4. 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

  5. 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

  6. Exploring bioactive properties of marine cyanobacteria isolated from the Portuguese coast: high potential as a source of anticancer compounds.

    PubMed

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

    2014-01-01

    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

  7. 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

  8. 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

  9. 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...

  10. 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. PMID:20456936

  11. 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.

  12. Climate change and regulation of hepatotoxin production in Cyanobacteria.

    PubMed

    Gehringer, Michelle M; Wannicke, Nicola

    2014-04-01

    Harmful, bloom-forming cyanobacteria (CyanoHABs) are occurring with increasing regularity in freshwater and marine ecosystems. The most commonly occurring cyanobacterial toxins are the hepatotoxic microcystin and nodularin. These cyclic hepta- and pentapeptides are synthesised nonribosomally by the gene products of the toxin gene clusters mcy and nda, respectively. Understanding of the regulation of hepatotoxin production is incomplete, although there is strong evidence supporting the roles of iron, light, higher nitrate availability and inorganic carbon in modulating microcystin levels. The majority of these studies have focused on the unicellular freshwater, microcystin-producing strain of Microcystis aeruginosa, with little attention being paid to terrestrial or marine toxin producers. This review intends to investigate the regulation of microcystin and nodularin production in unicellular and filamentous diazotrophic cyanobacteria against the background of changing climate conditions. Special focus is given to diazotrophic filamentous cyanobacteria, for example Nodularia spumigena, capable of regulating their nitrogen levels by actively fixing dinitrogen. By combining data from significant studies, an overall scheme of the regulation of toxin production is presented, focussing specifically on nodularin production in diazotrophs against the background of increasing carbon dioxide concentrations and temperatures envisaged under current climate change models. Furthermore, the risk of sustaining and spreading CyanoHABs in the future ocean is evaluated. PMID:24490596

  13. 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.

  14. 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…

  15. 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

  16. 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

  17. [Seasonal variation of cyanobacteria and its potential relationship with key environmental factors in Xiaojiang backwater area, Three Gorges Reservoir].

    PubMed

    Li, Zhe; Guo, Jing-song; Fang, Fang; Gao, Xu; Sheng, Jin-ping; Zhou, Hong; Long, Man

    2010-02-01

    Eutrophication and algal blooms occurred in the backwater areas of tributaries in Three Gorges Reservoir were the hot ecological issues in recent years. A one year field survey on cyanobacteria was put forward from May, 2007 to May, 2008 in Xiaojiang backwater area. 15 genera and 40 species of cyanophyta were detected. Mean value of cyanobacterial cell density was (23.50 +/- 10.30) x 10(5) cells x L(-1), i.e., 24.1% in the algal community, while the biomass was (768.70 +/- 287.40) microg x L(-1) which was 8.9% in the total biomass of algal community. Seasonal variation of cyanobacteria was apparent. Generally, cyanobacteria bloom occurred during late spring and early summer. Its abundance decreased after summer and reached the minimum level in winter. Anabaena, Aphanizomenon, Microcystis, Merismopedia and Phormidium were the common cynaobacterial genera. The cumulated cell density of these five genera of cyanobacteria above accounted up to 79.1% in the total cell density of cyanobacteria, while that of biomass accounted up to 77.6%. Spearman correlation analysis among the cell density, biomass as well as the key environmental factors indicated that utilization of inorganic nitrogen and phosphorus for anabolism was evident; however, nitrate would be the major nitrogen source for cyanobacteria. Moreover, increase of temperature and decrease of depth of euphotic zone had a significant effect on the abundance of cyanobacteria. According to co-analysis of hydrology and rainfall data in the whole year circle, it was found that nitrogen and phosphorus were input by the heavy rain and surface runoff with inorganic sediments, offering the enriched nutrients in water column. Meanwhile, turbidity increased by the inorganic suspended sediments decreased the depth of euphotic zone. The physiological advantage of cyanobacteria in low light and high turbidity environment might be the cause of cyanobacteria bloom in Xiaojiang backwater area. PMID:20391694

  18. 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

  19. Biomarkers involved in energy metabolism and oxidative stress response in the liver of Goodea gracilis Hubbs and Turner, 1939 exposed to the microcystin-producing Microcystis aeruginosa LB85 strain.

    PubMed

    Olivares Rubio, Hugo F; Martínez-Torres, M Lysset; Nájera-Martínez, Minerva; Dzul-Caamal, Ricardo; Domínguez-López, María Lilia; García-Latorre, Ethel; Vega-López, Armando

    2015-09-01

    Goodea gracilis is an endemic fish that only habitats in some water bodies of Central Mexico that are contaminated with cyanobacteria-producing microcystins (MC); however, a lack of information on this topic prevails. With the aim to generate the first approximation about the physiological changes elicited by cyanobacterium that produce MC congeners in this fish species, specimens born in the laboratory was exposed for 96 h to cell densities of 572.5, 1145, 2290, 4580, and 9160 × 10(6) cells of Microcystis aeruginosa strain LB85/L, and a set of novel endpoint related to hepatic gluconeogenesis (ADH/LDH) and pro-oxidant forces O2., H2 O2 ) in addition to biomarkers of oxidative damage and antioxidant response was evaluated in the liver. Results suggest that high inhibition of protein serine/threonine phosphatase (PP) may trigger many metabolic processes, such as those related to hepatic gluconeogenesis (ADH/LDH) and pro-oxidant O2⋅, H2 O2 , TBARS, ROOH, RC=O) as well as antioxidant (SOD, CAT, GPx) response to oxidative stress. Particularly, we observed that inhibition of LDH and PP, and H2 O2 increase and TBARS production were the key damages induced by high densities of M. aeruginosa. However, changes between aerobic and anaerobic metabolism related with ROS metabolism and ADH/LDH balance are apparently an acclimation of this fish species to exposure to cyanobacteria or their MCs. Fish species living in environments potentially contaminated with cyanobacteria or their MCs possess mechanisms of acclimation that allow them to offset the damage induced, even in the case of fish that have never been exposed to MCs. PMID:24639371

  20. 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

  1. Presence of potential toxin-producing cyanobacteria in an oligo-mesotrophic lake in Baltic Lake District, Germany: an ecological, genetic and toxicological survey.

    PubMed

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

    2014-10-01

    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

  2. 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. PMID:25060409

  3. 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

  4. 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

  5. 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. PMID:22794297

  6. *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...

  7. 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.

  8. 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

  9. Recent developments in therapeutic applications of Cyanobacteria.

    PubMed

    Raja, Rathinam; Hemaiswarya, Shanmugam; Ganesan, Venkatesan; Carvalho, Isabel S

    2016-05-01

    The cyanobacteria (blue-green algae) are photosynthetic prokaryotes having applications in human health with numerous biological activities and as a dietary supplement. It is used as a food supplement because of its richness in nutrients and digestibility. Many cyanobacteria (Microcystis sp, Anabaena sp, Nostoc sp, Oscillatoria sp., etc.) produce a great variety of secondary metabolites with potent biological activities. Cyanobacteria produce biologically active and chemically diverse compounds belonging to cyclic peptides, lipopeptides, fatty acid amides, alkaloids and saccharides. More than 50% of the marine cyanobacteria are potentially exploitable for extracting bioactive substances which are effective in killing cancer cells by inducing apoptotic death. Their role as anti-viral, anti-tumor, antimicrobial, anti-HIV and a food additive have also been well established. However, such products are at different stages of clinical trials and only a few compounds have reached to the market. PMID:25629310

  10. 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 ...

  11. 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 ...

  12. 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.

  13. Proteomic analysis of post translational modifications in cyanobacteria.

    PubMed

    Xiong, Qian; Chen, Zhuo; Ge, Feng

    2016-02-16

    Cyanobacteria are a diverse group of Gram-negative bacteria and the only prokaryotes capable of oxygenic photosynthesis. Recently, cyanobacteria have attracted great interest due to their crucial roles in global carbon and nitrogen cycles and their ability to produce clean and renewable biofuels. To survive in various environmental conditions, cyanobacteria have developed a complex signal transduction network to sense environmental signals and implement adaptive changes. The post-translational modifications (PTMs) systems play important regulatory roles in the signaling networks of cyanobacteria. The systematic investigation of PTMs could contribute to the comprehensive description of protein species and to elucidate potential biological roles of each protein species in cyanobacteria. Although the proteomic studies of PTMs carried out in cyanobacteria were limited, these data have provided clues to elucidate their sophisticated sensing mechanisms that contribute to their evolutionary and ecological success. This review aims to summarize the current status of PTM studies and recent publications regarding PTM proteomics in cyanobacteria, and discuss the novel developments and applications for the analysis of PTMs in cyanobacteria. Challenges, opportunities and future perspectives in the proteomics studies of PTMs in cyanobacteria are also discussed. PMID:26254007

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. Cutaneous hypersensitivity reactions to freshwater cyanobacteria – human volunteer studies

    PubMed Central

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

    2006-01-01

    Background Pruritic skin rashes associated with exposure to freshwater cyanobacteria are infrequently reported in the medical and scientific literature, mostly as anecdotal and case reports. Diagnostic dermatological investigations in humans are also infrequently described. We sought to conduct a pilot volunteer study to explore the potential for cyanobacteria to elicit hypersensitivity reactions. Methods A consecutive series of adult patients presenting for diagnostic skin patch testing at a hospital outpatient clinic were invited to participate. A convenience sample of volunteers matched for age and sex was also enrolled. Patches containing aqueous suspensions of various cyanobacteria at three concentrations were applied for 48 hours; dermatological assessment was made 48 hours and 96 hours after application. Results 20 outpatients and 19 reference subjects were recruited into the study. A single outpatient produced unequivocal reactions to several cyanobacteria suspensions; this subject was also the only one of the outpatient group with a diagnosis of atopic dermatitis. No subjects in the reference group developed clinically detectable skin reactions to cyanobacteria. Conclusion This preliminary clinical study demonstrates that hypersensitivity reactions to cyanobacteria appear to be infrequent in both the general and dermatological outpatient populations. As cyanobacteria are widely distributed in aquatic environments, a better appreciation of risk factors, particularly with respect to allergic predisposition, may help to refine health advice given to people engaging in recreational activities where nuisance cyanobacteria are a problem. PMID:16584576

  19. 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.

  20. 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

  1. 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. PMID:26306745

  2. 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

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

    PubMed

    Martins, Joana; Vasconcelos, Vitor

    2015-11-01

    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

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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....

  9. 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

  10. 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

  11. 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

  12. Multiple Gene Repression in Cyanobacteria Using CRISPRi.

    PubMed

    Yao, Lun; Cengic, Ivana; Anfelt, Josefine; Hudson, Elton P

    2016-03-18

    We describe the application of clustered regularly interspaced short palindromic repeats interference (CRISPRi) for gene repression in the model cyanobacterium Synechcocystis sp. PCC 6803. The nuclease-deficient Cas9 from the type-II CRISPR/Cas of Streptrococcus pyogenes was used to repress green fluorescent protein (GFP) to negligible levels. CRISPRi was also used to repress formation of carbon storage compounds polyhydroxybutryate (PHB) and glycogen during nitrogen starvation. As an example of the potential of CRISPRi for basic and applied cyanobacteria research, we simultaneously knocked down 4 putative aldehyde reductases and dehydrogenases at 50-95% repression. This work also demonstrates that tightly repressed promoters allow for inducible and reversible CRISPRi in cyanobacteria. PMID:26689101

  13. Genetic engineering of cyanobacteria as biodiesel feedstock.

    SciTech Connect

    Ruffing, Anne M.; 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 Sandia's 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.

  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. PMID:18267939

  15. 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

  16. 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

  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. 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.

  19. 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

  20. Cyanobacteria of the Genus Prochlorothrix†

    PubMed Central

    Pinevich, Alexander; Velichko, Natalia; Ivanikova, Natalia

    2012-01-01

    Green cyanobacteria differ from the blue–green cyanobacteria by the possession of a chlorophyll-containing light-harvesting antenna. Three genera of the green cyanobacteria namely Acaryochloris, Prochlorococcus, and Prochloron are unicellular and inhabit marine environments. Prochlorococcus marinus attracts most attention due to its prominent role in marine primary productivity. The fourth genus Prochlorothrix is represented by the filamentous freshwater strains. Unlike the other green cyanobacteria, Prochlorothrix strains are remarkably rare: to date, living isolates have been limited to two European locations. Taking into account fluctuating blooms, morphological resemblance to Planktothrix and Pseudanabaena, and unsuccessful attempts to obtain enrichments of Prochlorothrix, the most successful strategy to search for this cyanobacterium involves PCR with environmental DNA and Prochlorothrix-specific primers. This approach has revealed a broader distribution of Prochlorothrix. Marker genes have been found in at least two additional locations. Despite of the growing evidence for naturally occurring Prochlorothrix, there are only a few cultured strains with one of them (PCC 9006) being claimed to be axenic. In multixenic cultures, Prochlorothrix is accompanied by heterotrophic bacteria indicating a consortium-type association. The genus Prochlorothrix includes two species: P. hollandica and P. scandica based on distinctions in genomic DNA, cell size, temperature optimum, and fatty acid composition of membrane lipids. In this short review the properties of cyanobacteria of the genus Prochlorothrix are described. In addition, the evolutionary scenario for green cyanobacteria is suggested taking into account their possible role in the origin of simple chloroplast. PMID:22783229

  1. 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

  2. Cyanobacteria Affect Fitness and Genetic Structure of Experimental Daphnia Populations.

    PubMed

    Drugă, Bogdan; Turko, Patrick; Spaak, Piet; Pomati, Francesco

    2016-04-01

    Zooplankton communities can be strongly affected by cyanobacterial blooms, especially species of genus Daphnia, which are key-species in lake ecosystems. Here, we explored the effect of microcystin/nonmicrocystin (MC/non-MC) producing cyanobacteria in the diet of experimental Daphnia galeata populations composed of eight genotypes. We used D. galeata clones hatched from ephippia 10 to 60 years old, which were first tested in monocultures, and then exposed for 10 weeks as mixed populations to three food treatments consisting of green algae combined with cyanobacteria able/unable of producing MC. We measured the expression of nine genes potentially involved in Daphnia acclimation to cyanobacteria: six protease genes, one ubiquitin-conjugating enzyme gene, and two rRNA genes, and then we tracked the dynamics of the genotypes in mixed populations. The expression pattern of one protease and the ubiquitin-conjugating enzyme genes was positively correlated with the increased fitness of competing clones in the presence of cyanobacteria, suggesting physiological plasticity. The genotype dynamics in mixed populations was only partially related to the growth rates of clones in monocultures and varied strongly with the food. Our results revealed strong intraspecific differences in the tolerance of D. galeata clones to MC/non-MC-producing cyanobacteria in their diet, suggesting microevolutionary effects. PMID:26943751

  3. Cyanobacteria as a Platform for Biofuel Production

    PubMed Central

    Nozzi, Nicole E.; Oliver, John W. K.; Atsumi, Shota

    2013-01-01

    Cyanobacteria have great potential as a platform for biofuel production because of their fast growth, ability to fix carbon dioxide gas, and their genetic tractability. Furthermore they do not require fermentable sugars or arable land for growth and so competition with cropland would be greatly reduced. In this perspective we discuss the challenges and areas for improvement most pertinent for advancing cyanobacterial fuel production, including: improving genetic parts, carbon fixation, metabolic flux, nutrient requirements on a large scale, and photosynthetic efficiency using natural light. PMID:25022311

  4. 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

  5. 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...

  6. 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...

  7. 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.

  8. 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

  9. TOXINS FROM CYANOBACTERIA IN WATER

    EPA Science Inventory

    This project is part of a larger U. S. Environmental Protection Agency (EPA) effort, which includes the Office of Water, to investigate algal toxins in surface water supplies and drinking water. Toxins produced by cyanobacteria (blue-green algae) are among the most potent known ...

  10. 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

  11. 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

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

    PubMed

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

    2010-11-01

    N(2)-fixing cyanobacteria play an essential role in sustaining primary productivity in contemporary oceans and freshwater systems. However, the significance of N(2)-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 N(2)-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 N(2)-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

  13. 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

  14. Extending the biosynthetic repertoires of cyanobacteria and chloroplasts.

    PubMed

    Nielsen, Agnieszka Zygadlo; Mellor, Silas Busck; Vavitsas, Konstantinos; Wlodarczyk, Artur Jacek; Gnanasekaran, Thiyagarajan; Perestrello Ramos H de Jesus, Maria; King, Brian Christopher; Bakowski, Kamil; Jensen, Poul Erik

    2016-07-01

    Chloroplasts in plants and algae and photosynthetic microorganisms such as cyanobacteria are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals and complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression of the appropriate pathways, but this requires optimization of carbon flux and reducing power, and a thorough understanding of regulatory pathways. Secretion or storage of the compounds produced can be exploited for the isolation or confinement of the desired compounds. In this review, we explore the use of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the levels of production to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons derived from the photosynthetic light reactions, appears to be non-limiting, but redirection of the fixed carbon via precursor molecules presents a challenge. We also discuss the available synthetic biology tools and the need to expand the molecular toolbox to facilitate cellular reprogramming for increased production yields in both cyanobacteria and chloroplasts. PMID:27005523

  15. 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

  16. 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. PMID:19796131

  17. 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.

  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. 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.

  20. 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.

  1. Cyanobacteria blooms produce teratogenic retinoic acids

    PubMed Central

    Wu, Xiaoqin; Jiang, Jieqiong; Wan, Yi; Giesy, John P.; Hu, Jianying

    2012-01-01

    Deformed amphibians have been observed in eutrophic habitats, and some clues point to the retinoic acids (RAs) or RA mimics. However, RAs are generally thought of as vertebrate-specific hormones, and there was no evidence that RAs exist in cyanobacteria or algae blooms. By analyzing RAs and their analogs 4-oxo-RAs in natural cyanobacteria blooms and cultures of cyanobacteria and algae, we showed that cyanobacteria blooms could produce RAs, which were powerful animal teratogens. Intracellular RAs and 4-oxo-RAs with concentrations between 0.4 and 4.2 × 102 ng/L were detected in all bloom materials, and extracellular concentrations measured in water from Taihu Lake, China, were as great as 2.0 × 10 ng/L, which might pose a risk to wildlife through chronic exposure. Further examination of 39 cyanobacteria and algae species revealed that 32 species could produce RAs and 4-oxo-RAs (1.6–1.4 × 103 ng/g dry weight), and the dominant cyanobacteria species in Taihu Lake, Microcystis flos-aquae and Microcystis aeruginosa, produced high amounts of RAs and 4-oxo-RAs with concentrations of 1.4 × 103 and 3.7 × 102 ng/g dry weight, respectively. Most genera of cyanobacteria that could produce RAs and 4-oxo-RAs, such as Microcystis, Anabaena, and Aphanizomenon, often occur dominantly in blooms. Production of RAs and 4-oxo-RAs by cyanobacteria was associated with species, origin location, and growth stage. These results represent a conclusive demonstration of endogenous production of RAs in freshwater cyanobacteria blooms. The observation of teratogenic RAs in cyanobacteria is evolutionarily and ecologically significant because RAs are vertebrate-specific hormones, and cyanobacteria form extensive and highly visible blooms in many aquatic ecosystems. PMID:22645328

  2. 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

  3. 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

  4. 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

  5. Cyanobacteria as Cell Factories to Produce Plant Secondary Metabolites

    PubMed Central

    Xue, Yong; He, Qingfang

    2015-01-01

    Cyanobacteria represent a promising platform for the production of plant secondary metabolites. Their capacity to express plant P450 proteins, which have essential functions in the biosynthesis of many plant secondary metabolites, makes cyanobacteria ideal for this purpose, and their photosynthetic capability allows cyanobacteria to grow with simple nutrient inputs. This review summarizes the advantages of using cyanobacteria to transgenically produce plant secondary metabolites. Some techniques to improve heterologous gene expression in cyanobacteria are discussed. PMID:25973419

  6. 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

  7. 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.

  8. 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.

  9. 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...

  10. Deep water ventilation traced by Synechococcus cyanobacteria

    NASA Astrophysics Data System (ADS)

    Vilibić, Ivica; Šantić, Danijela

    2008-07-01

    The paper describes a finding of photoautotroph cyanobacteria Synechococcus in deep Adriatic waters during the spring of 2006. The maximum abundance in early May was positioned at 800 m, being of order of the values referred for the surface waters in the Adriatic Sea. The deep abundance maximum has been associated to the fast ventilation of deep Adriatic waters, usually occurring during wintertime strong cooling events. Two processes were detected: (1) deep convection in the South Adriatic Pit (SAP) and (2) density current going downslope. The first process was responsible for bringing the cyanobacteria down to 600-m depth in the area of convection, and the second one triggered the downslope transport of the cyanobacteria to the SAP very bottom. The depletion rate of Synechoccocus cyanobacteria in an extremely hostile environment has been computed to equal about 1 month.

  11. 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

  12. 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

  13. 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

  14. 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. PMID:24819926

  15. 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

  16. Cyanobacteria and Cyanotoxins: The Influence of Nitrogen versus Phosphorus

    PubMed Central

    Dolman, Andrew M.; Rücker, Jacqueline; Pick, Frances R.; Fastner, Jutta; Rohrlack, Thomas; Mischke, Ute; Wiedner, Claudia

    2012-01-01

    The importance of nitrogen (N) versus phosphorus (P) in explaining total cyanobacterial biovolume, the biovolume of specific cyanobacterial taxa, and the incidence of cyanotoxins was determined for 102 north German lakes, using methods to separate the effects of joint variation in N and P concentration from those of differential variation in N versus P. While the positive relationship between total cyanobacteria biovolume and P concentration disappeared at high P concentrations, cyanobacteria biovolume increased continually with N concentration, indicating potential N limitation in highly P enriched lakes. The biovolumes of all cyanobacterial taxa were higher in lakes with above average joint NP concentrations, although the relative biovolumes of some Nostocales were higher in less enriched lakes. Taxa were found to have diverse responses to differential N versus P concentration, and the differences between taxa were not consistent with the hypothesis that potentially N2-fixing Nostocales taxa would be favoured in low N relative to P conditions. In particular Aphanizomenon gracile and the subtropical invasive species Cylindrospermopsis raciborskii often reached their highest biovolumes in lakes with high nitrogen relative to phosphorus concentration. Concentrations of all cyanotoxin groups increased with increasing TP and TN, congruent with the biovolumes of their likely producers. Microcystin concentration was strongly correlated with the biovolume of Planktothrix agardhii but concentrations of anatoxin, cylindrospermopsin and paralytic shellfish poison were not strongly related to any individual taxa. Cyanobacteria should not be treated as a single group when considering the potential effects of changes in nutrient loading on phytoplankton community structure and neither should the N2-fixing Nostocales. This is of particular importance when considering the occurrence of cyanotoxins, as the two most abundant potentially toxin producing Nostocales in our study were

  17. 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. PMID:25585147

  18. 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

  19. 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

  20. 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

  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. PMID:25088450

  2. Epidemiology of recreational exposure to freshwater cyanobacteria – an international prospective cohort study

    PubMed Central

    Stewart, Ian; Webb, Penelope M; Schluter, Philip J; Fleming, Lora E; Burns, John W; Gantar, Miroslav; Backer, Lorraine C; Shaw, Glen R

    2006-01-01

    Background Case studies and anecdotal reports have documented a range of acute illnesses associated with exposure to cyanobacteria and their toxins in recreational waters. The epidemiological data to date are limited; we sought to improve on the design of some previously conducted studies in order to facilitate revision and refinement of guidelines for exposure to cyanobacteria in recreational waters. Methods A prospective cohort study was conducted to investigate the incidence of acute symptoms in individuals exposed, through recreational activities, to low (cell surface area <2.4 mm2/mL), medium (2.4–12.0 mm2/mL) and high (>12.0 mm2/mL) levels of cyanobacteria in lakes and rivers in southeast Queensland, the central coast area of New South Wales, and northeast and central Florida. Multivariable logistic regression analyses were employed; models adjusted for region, age, smoking, prior history of asthma, hay fever or skin disease (eczema or dermatitis) and clustering by household. Results Of individuals approached, 3,595 met the eligibility criteria, 3,193 (89%) agreed to participate and 1,331 (37%) completed both the questionnaire and follow-up interview. Respiratory symptoms were 2.1 (95%CI: 1.1–4.0) times more likely to be reported by subjects exposed to high levels of cyanobacteria than by those exposed to low levels. Similarly, when grouping all reported symptoms, individuals exposed to high levels of cyanobacteria were 1.7 (95%CI: 1.0–2.8) times more likely to report symptoms than their low-level cyanobacteria-exposed counterparts. Conclusion A significant increase in reporting of minor self-limiting symptoms, particularly respiratory symptoms, was associated with exposure to higher levels of cyanobacteria of mixed genera. We suggest that exposure to cyanobacteria based on total cell surface area above 12 mm2/mL could result in increased incidence of symptoms. The potential for severe, life-threatening cyanobacteria-related illness is likely to be

  3. 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

  4. 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

  5. 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

  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. 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...

  8. 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

  9. 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%.

  10. 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.

  11. 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

  12. 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

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

    PubMed

    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

  14. 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.

  15. 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

  16. 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. PMID:21893330

  17. 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.

  18. 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.

  19. CLASSIFICATION AND NOMENCLATURE OF VIRUSES OF CYANOBACTERIA

    EPA Science Inventory

    The Study Group finds it appropriate that viruses which have as their host cyanobacteria (blue-green algae) should be grouped within the well-categorized families of the bacterial viruses. Thus, the term cyanophage is adopted as a synonym for the vernacular name BGA virus (BGAV) ...

  20. Role of Spermidine in Overwintering of Cyanobacteria

    PubMed Central

    Zhu, Xiangzhi; Li, Qiong; Yin, Chuntao; Fang, Xiantao

    2015-01-01

    ABSTRACT Polyamines are found in all groups of cyanobacteria, but their role in environmental adaptation has been barely investigated. In Synechocystis sp. strain PCC 6803, inactivation of spermidine synthesis genes significantly reduced the survivability under chill (5°C)-light stress, and the survivability could be restored by addition of spermidine. To analyze the effects of spermidine on gene expression at 5°C, lacZ was expressed from the promoter of carboxy(nor)spermidine decarboxylase gene (CASDC) in Synechocystis. Synechocystis 6803::PCASDC-lacZ pretreated at 15°C showed a high level of LacZ activity for a long period of time at 5°C; without the pretreatment or with protein synthesis inhibited at 5°C, the enzyme activity gradually decreased. In a spermidine-minus mutant harboring PCASDC-lacZ, lacZ showed an expression pattern as if protein synthesis were inhibited at 5°C, even though the stability of its mRNA increased. Four other genes, including rpoA that encodes the α subunit of RNA polymerase, showed similar expression patterns. The chill-light stress led to a rapid increase of protein carbonylation in Synechocystis. The protein carbonylation then quickly returned to the background level in the wild type but continued to slowly increase in the spermidine-minus mutant. Our results indicate that spermidine promotes gene expression and replacement of damaged proteins in cyanobacteria under the chill-light stress in winter. IMPORTANCE Outbreak of cyanobacterial blooms in freshwater lakes is a worldwide environmental problem. In the annual cycle of bloom-forming cyanobacteria, overwintering is the least understood stage. Survival of Synechocystis sp. strain PCC 6803 under long-term chill (5°C)-light stress has been established as a model for molecular studies on overwintering of cyanobacteria. Here, we show that spermidine, the most common polyamine in cyanobacteria, promotes the survivability of Synechocystis under long-term chill-light stress and

  1. Some aspects of the ecophysiology of cyanobacteria.

    PubMed

    Mur, L R

    1983-01-01

    Fresh waters rich in nutrients often show mass development of cyanobacteria. The kind of cyanobacteria to be found depends on the properties of the lake. In non-stratified shallow lakes, the most common species Oscillatoria agardhii. In stratified lakes, cyanobacteria can be found in restricted zones of the deeper part of the lakes, and always possess cells with very active gas vacuoles. The most common species are Microcystis aeruginosa, Oscillatoria agardhii var isothrix, Oscillatoria "var red" and different Anabaena species. In lakes with prolonged nitrogen limitation, genera such as Anabaena and Aphanizomenon are common. Two important factors determine the distribution of these organisms: the light climate and the availability of nutrients. We have limited our discussion in this paper to the influence of the light climate. This influence of the light climate on growth can be determined in different ways. The influence of light intensity on the growth rate of Oscillatoria agardhii can be described using a Monod-like relation with light inhibition at light intensities above 40 W m-2. Studies with other species of cyanobacteria like Microcystis aeruginosa and Aphanizomenon flos-aquae support the assumption that most cyanobacteria living in fresh water are extremely sensitive to high light intensities. The energy balance of phototrophic growth can be described by the equation mu = qE . c - mue where mu is the specific growth rate, mue the specific maintenance energy rate and qE the specific light energy uptake rate; c represents the growth efficiency factor with which light energy is converted into cell material. In this equation, there are two factors which determine the growth of the organisms: ue and c. It was found that the value of mue of Oscillatoria was extremely low (mue approximately 0.001 h-1) compared with a eukaryotic organism (Scenedesmus: mue 0.008 h-1). The value of c was found to be dependent on the growth rate, but did not greatly differ from

  2. 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.

  3. Mixotrophic cyanobacteria and microalgae as distinctive biological agents for organic pollutant degradation.

    PubMed

    Subashchandrabose, Suresh R; Ramakrishnan, Balasubramanian; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

    2013-01-01

    Millions of natural and synthetic organic chemical substances are present in both soil and aquatic environments. Toxicity and/or persistence determine the polluting principle of these substances. The biological responses to these pollutants include accumulation and degradation. The responses of environments with organic pollutants are perceptible from the dwindling degradative abilities of microorganisms. Among different biological members, cyanobacteria and microalgae are highly adaptive through many eons, and can grow autotrophically, heterotrophically or mixotrophically. Mixotrophy in cyanobacteria and microalgae can provide many competitive advantages over bacteria and fungi in degrading organic pollutants. Laboratory culturing of strict phototrophic algae has limited the realization of their potential as bioremediation agents. In the natural assemblages, mixotrophic algae can contribute to sequestration of carbon, which is otherwise emitted as carbon dioxide to the atmosphere under heterotrophic conditions by other organisms. Molecular methods and metabolic and genomic information will help not only in identification and selection of mixotrophic species of cyanobacteria and microalgae with capabilities to degrade organic pollutants but also in monitoring the efficiency of remediation efforts under the field conditions. These organisms are relatively easier for genetic engineering with desirable traits. This review presents a new premise from the literature that mixotrophic algae and cyanobacteria are distinctive bioremediation agents with capabilities to sequester carbon in the environment. PMID:23201778

  4. 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

  5. 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

  6. Structural studies on photosystem II of cyanobacteria.

    PubMed

    Gabdulkhakov, A G; Dontsova, M V

    2013-12-01

    Photosynthesis is one of the most important chemical processes in the biosphere responsible for the maintenance of life on Earth. Light energy is converted into energy of chemical bonds in photoreaction centers, which, in particular, include photosystem II (PS II). PS II is a multisubunit pigment-protein complex located in the thylakoid membrane of cyanobacteria, algae and plants. PS II realizes the first stage of solar energy conversion that results in decomposition of water to molecular oxygen, protons, and bound electrons via a series of consecutive reactions. During recent years, considerable progress has been achieved in determination of the spatial structures of PS II from various cyanobacteria. In the present review, we outline the current state of crystallographic studies on PS II. PMID:24490738

  7. 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. PMID:26592144

  8. 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

  9. Blooms of cyanobacteria on the potomac river.

    PubMed

    Krogmann, D W; Butalla, R; Sprinkle, J

    1986-03-01

    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

  10. 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

  11. 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

  12. 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

  13. 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

  14. Recent Applications of Metabolomics Toward Cyanobacteria

    PubMed Central

    Schwarz, Doreen; Orf, Isabel; Kopka, Joachim; Hagemann, Martin

    2013-01-01

    Our knowledge on cyanobacterial molecular biology increased tremendously by the application of the “omics” techniques. Only recently, metabolomics was applied systematically to model cyanobacteria. Metabolomics, the quantitative estimation of ideally the complete set of cellular metabolites, is particularly well suited to mirror cellular metabolism and its flexibility under diverse conditions. Traditionally, small sets of metabolites are quantified in targeted metabolome approaches. The development of separation technologies coupled to mass-spectroscopy- or nuclear-magnetic-resonance-based identification of low molecular mass molecules presently allows the profiling of hundreds of metabolites of diverse chemical nature. Metabolome analysis was applied to characterize changes in the cyanobacterial primary metabolism under diverse environmental conditions or in defined mutants. The resulting lists of metabolites and their steady state concentrations in combination with transcriptomics can be used in system biology approaches. The application of stable isotopes in fluxomics, i.e. the quantitative estimation of carbon and nitrogen fluxes through the biochemical network, has only rarely been applied to cyanobacteria, but particularly this technique will allow the making of kinetic models of cyanobacterial systems. The further application of metabolomics in the concert of other “omics” technologies will not only broaden our knowledge, but will also certainly strengthen the base for the biotechnological application of cyanobacteria. PMID:24957891

  15. Cyanobacteria bloom: selective filter for zooplankton?

    PubMed

    Mello, N A S T; Maia-Barbosa, P M

    2015-01-01

    The Ibirité reservoir is an urban and eutrophic environment, with regular occurrences of cyanobacteria blooms. The reservoir is warm monomict and remains stratified most of the year, circulating in the dry season (winter). During the hydrological cycle of October/07 to October/08 there were four scenarios with different environmental conditions, which influenced the structure of the zooplankton community, as confirmed in a previous study. Changes in the zooplankton community structure between the scenarios were studied, aiming at analyzing the stability and persistence of this community. The Spearman's coefficient of correlation was used to measure the stability; the persistence was evaluated through a cluster analysis and changes in community composition were estimated by the "temporal" β diversity index. Considering the distribution patterns of abundance, the community was stable only in the transition between scenarios 1 and 2 (n = 30, r = 0.71, p = 0.00001), when there were no cyanobacteria blooms. The persistence of zooplankton between the scenarios was low, showing a distinct species composition for each scenario. The highest variations in species composition, observed by the values of temporal β diversity index, were the transitions between scenarios 3-0 (1.45) and 0-1 (1.05), and the lowest variations occurred in the transition between scenarios 1-2 (0.57). The results suggest that the cyanobacteria blooms at Ibirité reservoir are be acting as "selective filters", and are, thus, disturbances with sufficient ability to change the structure of the zooplankton community. PMID:25945634

  16. 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

  17. 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.

  18. 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. PMID:25865951

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Absence of sterols constrains food quality of cyanobacteria for an invasive freshwater bivalve.

    PubMed

    Basen, Timo; Rothhaupt, Karl-Otto; Martin-Creuzburg, Dominik

    2012-09-01

    The accumulation of cyanobacterial biomass may severely affect the performance of aquatic consumers. Here, we investigated the role of sterols in determining the food quality of cyanobacteria for the invasive clam Corbicula fluminea, which has become a common benthic invertebrate in many freshwater ecosystems throughout the world. In standardized growth experiments, juvenile clams were fed mixtures of different cyanobacteria (Anabaena variabilis, Aphanothece clathrata, Synechococcus elongatus) or sterol-containing eukaryotic algae (Cryptomonas sp., Nannochloropsis limnetica, Scenedesmus obliquus). In addition, the cyanobacterial food was supplemented with different sterols. We provide evidence that somatic growth of C. fluminea on cyanobacterial diets is constrained by the absence of sterols, as indicated by a growth-enhancing effect of sterol supplementation. Thus, our findings contribute to our understanding of the consequences of cyanobacterial mass developments for benthic consumers and highlight the importance of considering sterols as potentially limiting nutrients in aquatic food webs. PMID:22398861

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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

  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

    2015-01-01

    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.

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

    PubMed

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

    2013-09-01

    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. PMID:23286757

  19. 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.

  20. Inhibition of the growth of cyanobacteria during the recruitment stage in Lake Taihu.

    PubMed

    Lu, Yaping; Wang, Jin; Zhang, Xiaoqian; Kong, Fanxiang

    2016-03-01

    Microcystis is the dominant algal bloom genus in Lake Taihu. Thus, controlling the recruitment and growth of Microcystis is the most crucial aspect of solving the problem of algal blooms. Different concentrations (0.025, 0.05, and 0.1 g L(-1)) of tea extract were used to treat barrels of lake water at the recruitment stage of cyanobacteria. There was an inhibitory effect on algal growth in all treatment groups. The inhibitory effect on cyanobacteria was stronger than on other algae. The metabolic activity of cells in the treatment groups was significantly enhanced compared to the control, as an adaptation to the stress caused by tea polyphenols. The photosynthetic activity diminished in the treatment groups and was barely detected in the 0.05 and 0.1 g L(-1) treatments. The levels of reactive oxygen species increased substantially in treated cells with the algal cells experiencing oxidative damage. The effect of tea on zooplankton was also studied. The number of Bosmina fatalis individuals did not change significantly in the 0.025 and 0.05 g L(-1) treatments. These results suggested that the application of tea extracts, during the recruitment stage of blue-green algae, suppressed the recruitment and growth of cyanobacteria, thus offering the potential to prevent cyanobacterial blooms. PMID:26590061

  1. 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

  2. Mechanisms and fitness implications of photomorphogenesis during chromatic acclimation in cyanobacteria.

    PubMed

    Montgomery, Beronda L

    2016-07-01

    Photosynthetic organisms absorb photons and convert light energy to chemical energy through the process of photosynthesis. Photosynthetic efficiency is tuned in response to the availability of light, carbon dioxide and nutrients to promote maximal levels of carbon fixation, while simultaneously limiting the potential for light-associated damage or phototoxicity. Given the central dependence on light for energy production, photosynthetic organisms possess abilities to tune their growth, development and metabolism to external light cues in the process of photomorphogenesis. Photosynthetic organisms perceive light intensity and distinct wavelengths or colors of light to promote organismal acclimation. Cyanobacteria are oxygenic photosynthetic prokaryotes that exhibit abilities to alter specific aspects of growth, including photosynthetic pigment composition and morphology, in responses to changes in available wavelengths and intensity of light. This form of photomorphogenesis is known as chromatic acclimation and has been widely studied. Recent insights into the photosensory photoreceptors found in cyanobacteria and developments in our understanding of the molecular mechanisms initiated by light sensing to affect the changes characteristic of chromatic acclimation are discussed. I consider cyanobacterial responses to light, the broad diversity of photoreceptors encoded by these organisms, specific mechanisms of photomorphogenesis, and associated fitness implications in chromatically acclimating cyanobacteria. PMID:27217547

  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. Response of Daphnia's Antioxidant System to Spatial Heterogeneity in Cyanobacteria Concentrations in a Lowland Reservoir

    PubMed Central

    Wojtal-Frankiewicz, Adrianna; Bernasińska, Joanna; Frankiewicz, Piotr; Gwoździński, Krzysztof; Jurczak, Tomasz

    2014-01-01

    Many species and clones of Daphnia inhabit ecosystems with permanent algal blooms, and they can develop tolerance to cyanobacterial toxins. In the current study, we examined the spatial differences in the response of Daphnia longispina to the toxic Microcystis aeruginosa in a lowland eutrophic dam reservoir between June (before blooms) and September (during blooms). The reservoir showed a distinct spatial pattern in cyanobacteria abundance resulting from the wind direction: the station closest to the dam was characterised by persistently high Microcystis biomass, whereas the upstream stations had a significantly lower biomass of Microcystis. Microcystin concentrations were closely correlated with the cyanobacteria abundance (r = 0.93). The density of daphniids did not differ among the stations. The main objective of this study was to investigate how the distribution of toxic Microcystis blooms affects the antioxidant system of Daphnia. We examined catalase (CAT) activity, the level of the low molecular weight antioxidant glutathione (GSH), glutathione S-transferase (GST) activity and oxidative stress parameters, such as lipid peroxidation (LPO). We found that the higher the abundance (and toxicity) of the cyanobacteria, the lower the values of the antioxidant parameters. The CAT activity and LPO level were always significantly lower at the station with the highest M. aeruginosa biomass, which indicated the low oxidative stress of D. longispina at the site with the potentially high toxic thread. However, the low concentration of GSH and the highest activity of GST indicated the occurrence of detoxification processes at this site. These results demonstrate that daphniids that have coexisted with a high biomass of toxic cyanobacteria have effective mechanisms that protect them against the toxic effects of microcystins. We also conclude that Daphnia's resistance capacity to Microcystis toxins may differ within an ecosystem, depending on the bloom's spatial

  6. 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. PMID:25366827

  7. 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

  8. 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...

  9. Biosynthesis and Function of Extracellular Glycans in Cyanobacteria

    PubMed Central

    Kehr, Jan-Christoph; Dittmann, Elke

    2015-01-01

    The cell surface of cyanobacteria is covered with glycans that confer versatility and adaptability to a multitude of environmental factors. The complex carbohydrates act as barriers against different types of stress and play a role in intra- as well as inter-species interactions. In this review, we summarize the current knowledge of the chemical composition, biosynthesis and biological function of exo- and lipo-polysaccharides from cyanobacteria and give an overview of sugar-binding lectins characterized from cyanobacteria. We discuss similarities with well-studied enterobacterial systems and highlight the unique features of cyanobacteria. We pay special attention to colony formation and EPS biosynthesis in the bloom-forming cyanobacterium, Microcystis aeruginosa. PMID:25587674

  10. 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.

  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. 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.

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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. PMID:25462716

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

    PubMed Central

    Alamri, Saad A.; Mohamed, Zakaria A.

    2013-01-01

    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

  19. 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

  20. [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

  1. 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

  2. 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

  3. 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

  4. Nitrogen Fixed By Cyanobacteria Is Utilized By Deposit-Feeders

    PubMed Central

    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 δ15N close to -2‰, we expected the δ15N 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 δ15N 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 intra- and

  5. Analysis and elucidation of phosphoenolpyruvate carboxylase in cyanobacteria.

    PubMed

    Shylajanaciyar, Mohandass; Dineshbabu, Gnanasekaran; Rajalakshmi, Ramamoorthy; Subramanian, Gopalakrishnan; Prabaharan, Dharmar; Uma, Lakshmanan

    2015-02-01

    Phosphoenolpyruvate carboxylase (PEPC) a cytosolic enzyme of higher plants is also found in bacteria and cyanobacteria. Genetic and biochemical investigations have indicated that there are several isoforms of PEPC belonging to C3; C3/C4 and C4 groups but, the evolution of PEPC in cyanobacteria is not yet understood. The present study opens up an opportunity to understand the isoforms and functions of PEPC in cyanobacteria. The variations observed in PEPC among lower and higher orders of cyanobacteria, suggests convergent evolution of PEPC. There is a specific PEPC phosphorylation residue 'serine' at the N-terminus and PEPC determinant residue 'serine' at the C-terminal that facilitates high affinity for substrate binding. These residues were unique to higher orders of cyanobacteria, but, not in lower orders and other prokaryotes. The different PEPC forms of cyanobacteria were investigated for their kinetic properties with phosphoenolpyruvate as the substrate and the findings corroborated well with the in silico findings. In vitro enzymatic study of cyanobacteria belonging to three different orders demonstrated the role of aspartate as an allosteric effector, which inhibited PEPC by interacting with the highly conserved residues in the active site. The differences in mode of inhibition among the different order, thus, give a fair picture about the cyanobacterial PEPCs. The higher orders appear to possess the sequence coordinates and functionally conserved residues similar to isoforms of C4 type higher plants, whereas isoforms of PEPC of the lower orders did not resemble either that of C3 or C4 plants. PMID:25586080

  6. 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

  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. 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...

  9. 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. PMID:23863928

  10. 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...

  11. 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.

  12. 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

  13. 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. PMID:26341016

  14. 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. PMID:25009182

  15. Cellulose in Cyanobacteria. Origin of Vascular Plant Cellulose Synthase?

    PubMed Central

    Nobles, David R.; Romanovicz, Dwight K.; Brown, R. Malcolm

    2001-01-01

    Although cellulose biosynthesis among the cyanobacteria has been suggested previously, we present the first conclusive evidence, to our knowledge, of the presence of cellulose in these organisms. Based on the results of x-ray diffraction, electron microscopy of microfibrils, and cellobiohydrolase I-gold labeling, we report the occurrence of cellulose biosynthesis in nine species representing three of the five sections of cyanobacteria. Sequence analysis of the genomes of four cyanobacteria revealed the presence of multiple amino acid sequences bearing the DDD35QXXRW motif conserved in all cellulose synthases. Pairwise alignments demonstrated that CesAs from plants were more similar to putative cellulose synthases from Anabaena sp. Pasteur Culture Collection 7120 and Nostoc punctiforme American Type Culture Collection 29133 than any other cellulose synthases in the database. Multiple alignments of putative cellulose synthases from Anabaena sp. Pasteur Culture Collection 7120 and N. punctiforme American Type Culture Collection 29133 with the cellulose synthases of other prokaryotes, Arabidopsis, Gossypium hirsutum, Populus alba × Populus tremula, corn (Zea mays), and Dictyostelium discoideum showed that cyanobacteria share an insertion between conserved regions U1 and U2 found previously only in eukaryotic sequences. Furthermore, phylogenetic analysis indicates that the cyanobacterial cellulose synthases share a common branch with CesAs of vascular plants in a manner similar to the relationship observed with cyanobacterial and chloroplast 16s rRNAs, implying endosymbiotic transfer of CesA from cyanobacteria to plants and an ancient origin for cellulose synthase in eukaryotes. PMID:11598227

  16. 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

  17. 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

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

    PubMed Central

    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

  19. 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

  20. 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. PMID:26276824

  1. 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

  2. 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.

  3. 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

  4. 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

  5. Spatial and Temporal Patterns in the Seasonal Distribution of Toxic Cyanobacteria in Western Lake Erie from 2002–2014

    PubMed Central

    Wynne, Timothy T.; Stumpf, Richard P.

    2015-01-01

    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

  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. Natural products from cyanobacteria with antimicrobial and antitumor activity.

    PubMed

    Silva-Stenico, Maria Estela; Kaneno, Ramon; Zambuzi, Fabiana Albani; Vaz, Marcelo G M V; Alvarenga, Danillo O; Fiore, Marli Fátima

    2013-01-01

    Cyanobacteria are an important source of structurally bioactive metabolites, with cytotoxic, antiviral, anticancer, antimitotic, antimicrobial, specific enzyme inhibition and immunosuppressive activities. This study focused on the antitumor and antimicrobial activities of intra and extracellular cyanobacterial extracts. A total of 411 cyanobacterial strains were screened for antimicrobial activity using a subset of pathogenic bacteria as target. The in vitro antitumor assays were performed with extracts of 24 strains tested against two murine cancer cell lines (colon carcinoma CT-26 and lung cancer 3LL). Intracellular extracts inhibited 49 and 35% of Gram-negative and Gram-positive pathogenic bacterial growth, respectively. Furthermore, the methanolic intracellular extract of Cylindrospermopsis raciborskii CYP011K and Nostoc sp. CENA69 showed inhibitory activity against the cancer cell lines. The extracellular extract from Fischerella sp. CENA213 and M. aeruginosa NPJB-1 exhibited inhibitory activity against 3LL lung cancer cells at 0.8 µg ml⁻¹ and Oxynema sp. CENA135, Cyanobium sp. CENA154, M. aeruginosa NPJB-1 and M. aeruginosa NPLJ-4 presented inhibitory activity against CT26 colon cancer cells at 0.8 µg ml⁻¹. Other extracts were able to inhibit 3LL cell-growth at higher concentrations (20 µg ml⁻¹) such as Nostoc sp. CENA67, Cyanobium sp. CENA154 and M. aeruginosa NPLJ-4, while CT26 cells were inhibited at the same concentration by Nostoc sp. CENA67 and Fischerella sp. CENA213. These extracts presented very low inhibitory activity on human peripheral blood lymphocytes. The results showed that some cyanobacterial strains are a rich source of natural products with potential for pharmacological and biotechnological applications. PMID:24372264

  8. Oxidative phosphorylation and energy buffering in cyanobacteria.

    PubMed Central

    Nitschmann, W H; Peschek, G A

    1986-01-01

    The onset of respiration in the cyanobacteria Anacystis nidulans and Nostoc sp. strain Mac upon a shift from dark anaerobic to aerobic conditions was accompanied by rapid energization of the adenylate pool (owing to the combined action of ATP synthase and adenylate kinase) and also the guanylate, uridylate, and cytidylate pools (owing to nucleoside diphosphate and nucleoside monophosphate kinases). Rates of the various transphosphorylation reactions were comparable to the rate of oxidative phosphorylation, thus explaining, in part, low approximately P/O ratios which incorporate adenylates only. The increase of ATP, GTP, UTP, and CTP levels (nanomoles per minute per milligram [dry weight]) in oxygen-pulsed cells of A. nidulans and Nostoc species was calculated to be, on average, 2.3, 1.05, 0.8, and 0.57, respectively. Together with aerobic steady-state pool sizes of 1.35, 0.57, 0.5, and 0.4 nmol/mg (dry weight) for these nucleotides, a fairly uniform turnover of 1.3 to 1.5 min-1 was derived. All types of nucleotides, therefore, may be conceived of as being in equilibrium with each other, reflecting the energetic homeostasis or energy buffering of the (respiring) cyanobacterial cell. For the calculation of net efficiencies of oxidative phosphorylation in terms of approximately P/O ratios, this energy buffering was taken into account. Moreover, in A. nidulans an additional 30% of the energy initially conserved in ATP by oxidative phosphorylation was immediately used up by a plasma membrane-bound reversible H+-ATPase for H+ extrusion. Consequently, by allowing for energy buffering and ATPase-linked H+ extrusion, maximum P/O ratios of 2.6 to 3.3 were calculated. By contrast, in Nostoc sp. all the H+ extrusion, appeared to be linked to a plasma membrane-bound respiratory chain, thus bypassing any ATP formation and leading to P/O ratios of only 1.3 to 1.5 despite the correction for energy buffering. PMID:3023299

  9. 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 ...

  10. 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). PMID:26304815

  11. Cyanobacteria in wetlands of the industrialized Sambalpur District of India

    PubMed Central

    2013-01-01

    Background Cyanobacteria are common components of phytoplankton communities in most freshwater ecosystems. Proliferations of cyanobacteria are often caused by high nutrient loading, and as such can serve as indicators of declining water quality. Massive industrialization in developing countries, like India, has polluted fresh water bodies, including wetlands. Many industries directly discard their effluents to nearby water sources without treatment. In the Sambalpur District of India effluents reach the reservoir of the worlds largest earthen dam i.e Hirakud Dam. This study examines cyanobacteria communities in the wetlands of Sambalpur District, Odisha, India, including areas subjected to industrial pollution. Result & Discussion The genera Anabaena, Oscillatoria, Chroococcus, Phormidium were dominant genera of polluted wetlands of Sambalpur districts. A positive correlation was found between total cyanobacterial species and dissolved oxygen levels, but cyanobacterial diversity was inversely related to BOD, COD, TSS, and TDS. High dissolved oxygen content was also associated with regions of lower cyanobacteria biomass. Conclusion Cyanobacterial abundance was positively correlated to content of oxidisable organic matter, but negatively correlated to species diversity. Lower dissolved oxygen was correlated to decreased diversity and increased dominance by Anabaena, Oscillatoria, Chroococcus, Phormidium species, observed in regions characterized by deteriorated water quality. PMID:23845058

  12. 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.

  13. Role of signal peptides in targeting of proteins in cyanobacteria.

    PubMed Central

    Mackle, M M; Zilinskas, B A

    1994-01-01

    Proteins of cyanobacteria may be transported across one of two membrane systems: the typical eubacterial cell envelope (consisting of an inner membrane, periplasmic space, and an outer membrane) and the photosynthetic thylakoids. To investigate the role of signal peptides in targeting in cyanobacteria, Synechococcus sp. strain PCC 7942 was transformed with vectors carrying the chloramphenicol acetyltransferase reporter gene fused to coding sequences for one of four different signal peptides. These included signal peptides of two proteins of periplasmic space origin (one from Escherichia coli and the other from Synechococcus sp. strain PCC 7942) and two other signal peptides of proteins located in the thylakoid lumen (one from a cyanobacterium and the other from a higher plant). The location of the gene fusion products expressed in Synechococcus sp. strain PCC 7942 was determined by a chloramphenicol acetyltransferase enzyme-linked immunosorbent assay of subcellular fractions. The distribution pattern for gene fusions with periplasmic signal peptides was different from that of gene fusions with thylakoid lumen signal peptides. Primary sequence analysis revealed conserved features in the thylakoid lumen signal peptides that were absent from the periplasmic signal peptides. These results suggest the importance of the signal peptide in protein targeting in cyanobacteria and point to the presence of signal peptide features conserved between chloroplasts and cyanobacteria for targeting of proteins to the thylakoid lumen. Images PMID:8144451

  14. 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

  15. CYANOBACTERIA AND FISH: A TOXIC HEALTH THREAT TO TRIBAL COMMUNITIES?

    EPA Science Inventory

    It is expected that the cyanotoxin microcystin will be found in trout collected from lakes with cyanobacteria blooms. The results from this study will be used in conjunction with a fish consumption survey recently conducted by the Colville Confederated tribes and the U.S. E...

  16. 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. 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.

  17. 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.

  18. 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 [9].

  19. 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

  20. 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. PMID:24320697

  1. DETECTION OF CYANOBACTERIA AND THEIR TOXINS IN WATER

    EPA Science Inventory

    Blooms of cyanobacteria, also known as blue-green algae, have recently become more prevalent worldwide as a result of human activities. The long-term chronic human health hazard attributable to toxic cyanotoxins in drinking water has caused considerable concern in humans. Conti...

  2. 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...

  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. Molybdenum Storage in Cyanobacteria: "Mopping" Up Excess Mo

    NASA Astrophysics Data System (ADS)

    Glass, J. B.; Wolfe-Simon, F.; Anbar, A. D.

    2008-12-01

    The heavy metal molybdenum (Mo) plays an essential role in the nitrogen (N) cycle. In order to acquire N from the environment, microorganisms utilize Mo-containing enzymes such as nitrogenase (for N2 fixation) and nitrate reductase (for NO3- assimilation). N2-fixing cyanobacteria likely played an important role in both marine and terrestrial N cycling throughout Earth history. Low Mo levels in Precambrian oceans may have necessitated evolution of cyanobacterial Mo-storage ("Mop") proteins. If so, mop genes were likely lost in marine cyanobacteria after the rise of Mo (to approximately 100 nanomolar (nM) 600 Ma (Scott et al., 2008)). The distribution of mop genes in N2-fixing cyanobacteria supports this hypothesis; freshwater species contain this gene whereas marine species lack it. To assess the importance of Mo-storage in modern environments we are integrating laboratory and field investigations. In the lab, we grew N2-fixing freshwater cyanobacteria possessing the mop gene at high Mo levels (1500 nM) to assess whether excess Mo is accumulated Extremely high intracellular accumulation of Mo, much higher than could be accounted for by nitrogenase requirements alone, was observed. Investigation of mop gene expression and protein localization in Mo-replete and deplete conditions is underway. In the field, we are isolating indigenous cyanobacteria and cloning mop genes from Castle Lake, California. This field locale is of particular interest because previous studies show that periphyton consortia in this lake assimilate large quantities of N, even though Mo concentrations are <5 nM. This adaptation to low Mo may be aided by intracellular Mo storage.

  5. 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.

  6. 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.

  7. Assessing the antibiotic susceptibility of freshwater Cyanobacteria spp.

    PubMed Central

    Dias, Elsa; Oliveira, Micaela; Jones-Dias, Daniela; Vasconcelos, Vitor; Ferreira, Eugénia; Manageiro, Vera; Caniça, Manuela

    2015-01-01

    Freshwater is a vehicle for the emergence and dissemination of antibiotic resistance. Cyanobacteria are ubiquitous in freshwater, where they are exposed to antibiotics and resistant organisms, but their role on water resistome was never evaluated. Data concerning the effects of antibiotics on cyanobacteria, obtained by distinct methodologies, is often contradictory. This emphasizes the importance of developing procedures to understand the trends of antibiotic susceptibility in cyanobacteria. In this study we aimed to evaluate the susceptibility of four cyanobacterial isolates from different genera (Microcystis aeruginosa, Aphanizomenon gracile, Chrisosporum bergii, Planktothix agradhii), and among them nine isolates from the same specie (M. aeruginosa) to distinct antibiotics (amoxicillin, ceftazidime, ceftriaxone, kanamycine, gentamicine, tetracycline, trimethoprim, nalidixic acid, norfloxacin). We used a method adapted from the bacteria standard broth microdilution. Cyanobacteria were exposed to serial dilution of each antibiotic (0.0015–1.6 mg/L) in Z8 medium (20 ± 1°C; 14/10 h L/D cycle; light intensity 16 ± 4 μEm−2s−1). Cell growth was followed overtime (OD450nm/microscopic examination) and the minimum inhibitory concentrations (MICs) were calculated for each antibiotic/isolate. We found that β-lactams exhibited the lower MICs, aminoglycosides, tetracycline and norfloxacine presented intermediate MICs; none of the isolates were susceptible to trimethoprim and nalidixic acid. The reduced susceptibility of all tested cyanobacteria to some antibiotics suggests that they might be naturally non-susceptible to these compounds, or that they might became non-susceptible due to antibiotic contamination pressure, or to the transfer of genes from resistant bacteria present in the environment. PMID:26322027

  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. PMID:26406539

  9. The Regulation of Light Sensing and Light-Harvesting Impacts the Use of Cyanobacteria as Biotechnology Platforms.

    PubMed

    Montgomery, Beronda L

    2014-01-01

    Light is harvested in cyanobacteria by chlorophyll-containing photosystems embedded in the thylakoid membranes and phycobilisomes (PBSs), photosystem-associated light-harvesting antennae. Light absorbed by the PBSs and photosystems can be converted to chemical energy through photosynthesis. Photosynthetically fixed carbon pools, which are constrained by photosynthetic light capture versus the dissipation of excess light absorbed, determine the available organismal energy budget. The molecular bases of the environmental regulation of photosynthesis, photoprotection, and photomorphogenesis are still being elucidated in cyanobacteria. Thus, the potential impacts of these phenomena on the efficacy of developing cyanobacteria as robust biotechnological platforms require additional attention. Current advances and persisting needs for developing cyanobacterial production platforms that are related to light sensing and harvesting include the development of tools to balance the utilization of absorbed photons for conversion to chemical energy and biomass versus light dissipation in photoprotective mechanisms. Such tools can be used to direct energy to more effectively support the production of desired bioproducts from sunlight. PMID:25023122

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

    PubMed Central

    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. PMID:22408640

  11. Fine-structural analysis of black band disease-infected coral reveals boring cyanobacteria and novel bacteria.

    PubMed

    Miller, Aaron W; Blackwelder, Patricia; Al-Sayegh, Husain; Richardson, Laurie L

    2011-02-22

    Examination of coral fragments infected with black band disease (BBD) at the fine- and ultrastructural levels using scanning (SEM) and transmission electron microscopy (TEM) revealed novel features of the disease. SEM images of the skeleton from the host coral investigated (Montastraea annularis species complex) revealed extensive boring underneath the BBD mat, with cyanobacterial filaments present within some of the bore holes. Cyanobacteria were observed to penetrate into the overlying coral tissue from within the skeleton and were present throughout the mesoglea between tissue layers (coral epidermis and gastrodermis). A population of novel, as yet unidentified, small filamentous bacteria was found at the leading edge of the migrating band. This population increased in number within the band and was present within degrading coral epithelium, suggesting a role in disease etiology. In coral tissue in front of the leading edge of the band, cyanobacterial filaments were observed to be emerging from bundles of sloughed-off epidermal tissue. Degraded gastrodermis that contained actively dividing zooxanthellae was observed using both TEM and SEM. The BBD mat contained cyanobacterial filaments that were twisted, characteristic of negative-tactic responses. Some evidence of boring was found in apparently healthy control coral fragments; however, unlike in BBD-infected fragments, there were no associated cyanobacteria. These results suggest the coral skeleton as a possible source of pathogenic BBD cyanobacteria. Additionally, SEM revealed the presence of a potentially important group of small, filamentous BBD-associated bacteria yet to be identified. PMID:21516970

  12. 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. PMID:24429778

  13. 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

  14. CphA2 is a novel type of cyanophycin synthetase in N2-fixing cyanobacteria.

    PubMed

    Klemke, Friederike; Nürnberg, Dennis J; Ziegler, Karl; Beyer, Gabriele; Kahmann, Uwe; Lockau, Wolfgang; Volkmer, Thomas

    2016-03-01

    Most cyanobacteria use a single type of cyanophycin synthetase, CphA1, to synthesize the nitrogen-rich polymer cyanophycin. The genomes of many N2-fixing cyanobacteria contain an additional gene that encodes a second type of cyanophycin synthetase, CphA2. The potential function of this enzyme has been debated due to its reduced size and the lack of one of the two ATP-binding sites that are present in CphA1. Here, we analysed CphA2 from Anabaena variabilis ATCC 29413 and Cyanothece sp. PCC 7425. We found that CphA2 polymerized the dipeptide β-aspartyl-arginine to form cyanophycin. Thus, CphA2 represents a novel type of cyanophycin synthetase. A cphA2 disruption mutant of A. variabilis was generated. Growth of this mutant was impaired under high-light conditions and nitrogen deprivation, suggesting that CphA2 plays an important role in nitrogen metabolism under N2-fixing conditions. Electron micrographs revealed that the mutant had fewer cyanophycin granules, but no alteration in the distribution of granules in its cells was observed. Localization of CphA2 by immunogold electron microscopy demonstrated that the enzyme is attached to cyanophycin granules. Expression of CphA1 and CphA2 was examined in Anabaena WT and cphA mutant cells. Whilst the CphA1 level increased upon nitrogen deprivation, the CphA2 level remained nearly constant. PMID:26781249

  15. 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. PMID:22869418

  16. 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

  17. Probabilistic prediction of cyanobacteria abundance in a Korean reservoir using a Bayesian Poisson model

    NASA Astrophysics Data System (ADS)

    Cha, YoonKyung; Park, Seok Soon; Kim, Kyunghyun; Byeon, Myeongseop; Stow, Craig A.

    2014-03-01

    There have been increasing reports of harmful algal blooms (HABs) worldwide. However, the factors that influence cyanobacteria dominance and HAB formation can be site-specific and idiosyncratic, making prediction challenging. The drivers of cyanobacteria blooms in Lake Paldang, South Korea, the summer climate of which is strongly affected by the East Asian monsoon, may differ from those in well-studied North American lakes. Using the observational data sampled during the growing season in 2007-2011, a Bayesian hurdle Poisson model was developed to predict cyanobacteria abundance in the lake. The model allowed cyanobacteria absence (zero count) and nonzero cyanobacteria counts to be modeled as functions of different environmental factors. The model predictions demonstrated that the principal factor that determines the success of cyanobacteria was temperature. Combined with high temperature, increased residence time indicated by low outflow rates appeared to increase the probability of cyanobacteria occurrence. A stable water column, represented by low suspended solids, and high temperature were the requirements for high abundance of cyanobacteria. Our model results had management implications; the model can be used to forecast cyanobacteria watch or alert levels probabilistically and develop mitigation strategies of cyanobacteria blooms.

  18. 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

  19. [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. PMID:25055666

  20. Treatment of mixed domestic-industrial wastewater using cyanobacteria.

    PubMed

    El-Bestawy, Ebtesam

    2008-11-01

    Alexandria Sanitary Drainage Company (ASDCO), Alexandria, Egypt has two primary treatment plants, the eastern and the western wastewater treatment plants (EWTP and WWTP) that receive mixed domestic-industrial influents and discharge into L. Mariut. The lake is subjected therefore to severe levels of pollution and dominated by members of cyanobacteria that can cope with the high pollution load in the lake water. Isolation and utilization of the locally generated cyanobacterial biomass for remediation processes of highly toxic pollutants offers a very efficient and cheap tool for governmental or private industrial activities in Alexandria and will generate a source of revenue in Egyptian localities. The main objective of the present study was to investigate the biodegradation and biosorption capacity of some potential cyanobacterial species dominating the lake ecosystem toward organic and inorganic contaminants polluting the primary-treated effluents of the EWTP and WWTP. The primary effluents were subjected to biological treatment using three axenic cyanobacterial strains (Anabaena oryzae, Anabaena variabilis and Tolypothrix ceytonica) as batch system for 7 days. Removal efficiencies (RE) of the different contaminants were evaluated and compared. Results confirmed the high efficiencies of the investigated species for the removal of the target contaminants which were species and contaminant-dependent. BOD5 and COD recorded 89.29 and 73.68% as maximum RE(s) achieved by Anabaena variabilis and Anabaena oryzae, respectively. The highest RE of the TSS recorded 64.37% achieved by Tolypothrix ceytonica, while 38.84% was recorded as the highest TSD RE achieved by Anabaena variabilis. Tolypothrix ceytonica also exhibited the highest RE for FOG recorded 93.75%. Concerning the contaminant metals, Tolypothrix ceytonica showed the highest biosorption capacity where 86.12 and 94.63% RE were achieved for Zn and Cu, respectively. In conclusion, results of the present study

  1. Evolution of Saxitoxin Synthesis in Cyanobacteria and Dinoflagellates

    PubMed Central

    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

  2. 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

  3. 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.

  4. An osmotic stress protein of cyanobacteria is immunologically related to plant dehydrins.

    PubMed

    Close, T J; Lammers, P J

    1993-03-01

    Dehydrins are a family of desiccation proteins that were identified originally in plants (T.J. Close, A.A. Kortt, P.M. Chandler [1989] Plant Mol Biol 13: 95-108; G. Galau, T.J. Close [1992] Plant Physiol 98: 1523-1525). Dehydrins are characterized by the consensus amino acid sequence domain EKKGIMDKIKEKLPG found at or near the carboxy terminus; the core of this domain (KIKEKLPG) may be repeated from one to many times within the complete polypeptide. Dehydrins generally accumulate in plants in response to dehydration stress, regardless of whether the stimulus is evaporation, chilling, or a decrease in external osmotic potential. Polyclonal antibodies highly specific to the consensus carboxy terminus of plant dehydrins were used to search for dehydrins in cyanobacteria, many of which are known to survive desiccation. A 40-kD osmotic-stress-induced protein was identified in Anabaena sp. strain PCC 7120. The 40-kD protein was usually not detected in logarithmic cultures and was induced by shifting the growth medium to higher solute concentrations. Several solutes have inductive effects, including sucrose, sorbitol, and polyethylene glycol (PEG). Measurements of osmotic potential suggest that a shift of -0.5 MPa (sucrose and PEG) or -1.2 MPa (sorbitol) is sufficient to induce synthesis of the 40-kD protein. Glycerol, which is highly permeable, was not an inducer at -1.2 MPa (0.5 M), nor was the plant hormone abscisic acid. Induction appears to be evoked by a shift in osmotic potential approximately equal in absolute magnitude to the expected turgor pressure of bacterial cells in logarithmic phase growth. A dehydrin-like polypeptide was also identified among osmotically induced proteins from two other filamentous, heterocyst-forming cyano-bacteria. A 40-kD protein was observed in Calothrix sp. strain PCC 7601, and in Nostoc sp. strain Mac-R2, an osmotic-induced doublet at 39 and 40 kD was observed. From these data, it appears that cyanobacteria produce a dehydrin

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Use of filamentous cyanobacteria for biodegradation of organic pollutants.

    PubMed Central

    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. PMID:7534052

  10. 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

  11. 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

  12. Insect (Locusta migratoria migratorioides) test monitoring the toxicity of cyanobacteria.

    PubMed

    Hiripi, L; Nagy, L; Kalmár, T; Kovács, A; Vörös, L

    1998-01-01

    An insect test was developed to investigate the toxicity of cyanobacteria. The African locust, Locusta migratoria migratorioides R.F. was used as a test animal instead of mouse. The cyanobacteria tested were Aphanizomenon flos-aque, Anabaena aphanizomenoides, Cylindrospermopsis raciborskii, Microcystis aeruginosa. The toxicity of authentic microcystin-LR was also tested. Cyanobacteria producing toxins killed the animals when the homogenized cell suspension was injected into the animals. The locust test proved to be more sensitive than the mouse test. The LD50 values of the different cyanobacteria for locusts and for mice, respectively were the following: 90 microg/animal (60 mg/kg) and 8000 microg/animal (320 mg/kg), for Aphanizomenon flos-aquae; 255 microg/animal (170.2 mg/kg) and 3750 microg/animal (150 mg/kg), for Anabaena aphanizomenoides; 195 microg/animal (131.4 mg/kg) and 5750 microg/animal (230 mg/kg), for Cylindrospermopsis raciborskii; 22.5 microg/animal (15 mg/kg) and 6000 microg/ animal (240 mg/kg), for Microcystis aeruginosa. In locusts the LD50 value for authentic microcystin-LR was 0.2 microg/animal (130 mg/kg). Since the weight of the mice is 15 to 20 times larger than that of the locusts, hence less toxic cells are needed to kill the locusts. The locust test is cheaper than the mouse test, large number of animals can be used in the experiments and the LD50 values can be estimated more precisely. The toxicity of C. raciborskii was significantly lower when the lyophilized cells were extracted in methanol (LD50 = 767 mg/kg), instead of NaCl solution (LD50 = 131.4 mg/kg). PMID:9745918

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

    PubMed

    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

  14. 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

  15. 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

  16. 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

  17. 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. PMID:12495179

  18. Modelling the response of cyanobacteria to pH-variability on seasonal to decadal time scales

    NASA Astrophysics Data System (ADS)

    Hofmeister, Richard; Hinners, Jana; Hense, Inga

    2015-04-01

    Cyanobacteria blooms regularly occurred in the Baltic Sea during the last decades. The possible effects of increasing temperatures and eutrophication on cyanobacteria have been already investigated. This model study concentrates on the combined effect of expected temperature increase and ocean acidification on cyanobacteria blooms in the Baltic Sea. We make use of an established model system that comprises the life cycle model of cyanobacteria (CLC) and a biogeochemical model (ERGOM), a carbon chemistry model, and the water column model GOTM. These models are modularly coupled through the framework for aquatic biogeochemical models (FABM). In the CLC model, the cyanobacteria growth is dependent on the sea water pH following the results of experimental studies. The numerical experiments are forced by the output of a regional climate model (RCAO) for the period 1960-2100. A number of simulations are performed for different configurations of the coupled ecosystem, in order to estimate the effect of acidification and the effect of seasonally varying pH on the cyanobacteria bloom. Our simulation experiments show that cyanobacteria growth is stimulated by the increase of temperature in the future, while the blooms' strength decreases in the second half of the 21th century due to ocean acidification. The magnitude and trend of cyanobacteria concentrations are also affected by the seasonal variations of pH. Overall, the results show that the combined effect of the climate stressors, warming and acidification, on the cyanobacteria bloom is weak.

  19. Integration vector for the cyanobacteria Synechocystis sp. 6803

    SciTech Connect

    Shestakov, S.V.; Elanskaya, I.V.; Bibikova, M.V.

    1985-11-01

    The authors have constructed recombinant plasmid DNA molecules with fragments of chromosomal DNA of the cyanobacterium Synechocystis 6803 in the vector plasmid pACYC 184, carrying markers for resistance against tetracycline (TC/sup r/) and chloramphenicol (Cm/sup r/). The authors also present their scheme of constructing integration vectors for Synechocystis 6803. To demonstrate integration of the recombinant plasmids of pSIS and pSIB series into the chromosomes of cyanobacteria, chromosomal DNA was isolated from the Cm/sup r/ transformants of Synechocystis 6803, and used for blot-hybridization using P 32-labeled plasmid DNA of pACYC 184. The hybridization results show that the chromosomal DNA isolated from the Cm/sup r/ transformants of cyanobacteria carries a region homologous with plasmid pACYC 184, whereas the DNA from wild type cells does not hybridize with pACYC 184. The transformation frequency of the Synechocystis 6803 cells by chromosomal DNA from the Cm/sup r/ clones of cyanobacteria was 3-7 x 10/sup -5/, which corresponds to the frequency of chromosomal transformation for other markers.

  20. 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

  1. 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

  2. Incorporating nitrogen fixing cyanobacteria in the global biogeochemical model HAMOCC

    NASA Astrophysics Data System (ADS)

    Paulsen, Hanna; Ilyina, Tatiana; Six, Katharina

    2015-04-01

    Nitrogen fixation by marine diazotrophs plays a fundamental role in the oceanic nitrogen and carbon cycle as it provides a major source of 'new' nitrogen to the euphotic zone that supports biological carbon export and sequestration. Since most global biogeochemical models include nitrogen fixation only diagnostically, they are not able to capture its spatial pattern sufficiently. Here we present the incorporation of an explicit, dynamic representation of diazotrophic cyanobacteria and the corresponding nitrogen fixation in the global ocean biogeochemical model HAMOCC (Hamburg Ocean Carbon Cycle model), which is part of the Max Planck Institute for Meteorology Earth system model (MPI-ESM). The parameterization of the diazotrophic growth is thereby based on available knowledge about the cyanobacterium Trichodesmium spp., which is considered as the most significant pelagic nitrogen fixer. Evaluation against observations shows that the model successfully reproduces the main spatial distribution of cyanobacteria and nitrogen fixation, covering large parts of the tropical and subtropical oceans. Besides the role of cyanobacteria in marine biogeochemical cycles, their capacity to form extensive surface blooms induces a number of bio-physical feedback mechanisms in the Earth system. The processes driving these interactions, which are related to the alteration of heat absorption, surface albedo and momentum input by wind, are incorporated in the biogeochemical and physical model of the MPI-ESM in order to investigate their impacts on a global scale. First preliminary results will be shown.

  3. Studies on mineral phosphate solubilization by cyanobacteria Westiellopsis and Anabaena.

    PubMed

    Yandigeri, Mahesh S; Kashyap, Sudhanshu; Yadav, Arvind K; Srinavasan, Ramakrishnan; Pabbi, Sunil

    2011-01-01

    Two diazotrophic cyanobacteria, Westiellopsis prolifica and Anabaena variabilis were evaluated for elucidating the possible mechanism of mineral phosphate solubilization. Phosphate starved cyanobacteria evaluated for the presence of organic acids, extracellular compounds or enzymes that might have been produced and promoted the mineral phosphate solubilization with Mussorie Rock Phosphate and Tricalcium Phosphate as substrates. Both the cultures did not reveal production of organic acids throughout the incubation period when checked for decrease in pH of the media and thin layer chromatography Thin layer chromatography of culture filtrates showed the presence of hydrocarbon like compound. Further analysis of the culture filtrates with gas liquid chromatography, a single peak near to the retention time of 7.6 was observed in all extracts of culture filtrates irrespective of phosphate source. UV-visible spectra of culture filtrates revealed the absorption maxima of 276 nm. Gas Chromatographic-Mass Spectrometric analysis of culture filtrates showed most intense peak in the electron impact (EI) ionization was at m/z 149 and molecular ion peaks at m/z 207 and 167, inferring the presence of phthalic acid. Among the mechanisms in mineral phosphate solubilization, it was evident that these cyanobacteria used phthalic acid as possible mode of P solubilization. PMID:22073557

  4. Computational analysis of LexA regulons in Cyanobacteria

    PubMed Central

    2010-01-01

    Background The transcription factor LexA plays an important role in the SOS response in Escherichia coli and many other bacterial species studied. Although the lexA gene is encoded in almost every bacterial group with a wide range of evolutionary distances, its precise functions in each group/species are largely unknown. More recently, it has been shown that lexA genes in two cyanobacterial genomes Nostoc sp. PCC 7120 and Synechocystis sp. PCC 6803 might have distinct functions other than the regulation of the SOS response. To gain a general understanding of the functions of LexA and its evolution in cyanobacteria, we conducted the current study. Results Our analysis indicates that six of 33 sequenced cyanobacterial genomes do not harbor a lexA gene although they all encode the key SOS response genes, suggesting that LexA is not an indispensable transcription factor in these cyanobacteria, and that their SOS responses might be regulated by different mechanisms. Our phylogenetic analysis suggests that lexA was lost during the course of evolution in these six cyanobacterial genomes. For the 26 cyanobacterial genomes that encode a lexA gene, we have predicted their LexA-binding sites and regulons using an efficient binding site/regulon prediction algorithm that we developed previously. Our results show that LexA in most of these 26 genomes might still function as the transcriptional regulator of the SOS response genes as seen in E. coli and other organisms. Interestingly, putative LexA-binding sites were also found in some genomes for some key genes involved in a variety of other biological processes including photosynthesis, drug resistance, etc., suggesting that there is crosstalk between the SOS response and these biological processes. In particular, LexA in both Synechocystis sp. PCC6803 and Gloeobacter violaceus PCC7421 has largely diverged from those in other cyanobacteria in the sequence level. It is likely that LexA is no longer a regulator of the SOS response

  5. 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

  6. 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

  7. Targeted natural products discovery from marine cyanobacteria using combined phylogenetic and mass spectrometric evaluation.

    PubMed

    Salvador-Reyes, Lilibeth A; Engene, Niclas; Paul, Valerie J; Luesch, Hendrik

    2015-03-27

    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

  8. 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

  9. 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...

  10. 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.

  11. 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 ...

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Spectroradiometric monitoring for open outdoor culturing of algae and cyanobacteria.

    PubMed

    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 outdoor monitoring of green algae and cyanobacteria cultures with a multichannel, fiber-coupled spectroradiometer. Reflectance data acquired over a 4-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, which is 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 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 nonsampling measurement of biomass in outdoor ponds. Other fitting parameters in the reflectance model are compared with auxiliary measurements and physics-based calculations. The model-derived magnitudes of sunlight and skylight water-surface reflections compare favorably with Fresnel reflectance calculations, while the model-derived quantum efficiency of Chl-a fluorescence is found to be in agreement with literature values. Finally, the water temperatures derived from the reflectance model exhibit excellent agreement with thermocouple measurements during the morning hours but correspond to significantly elevated temperatures in the afternoon hours. PMID:25321139

  18. 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

  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. 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.

  1. 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

  2. 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

  3. Cytotoxicity in L929 fibroblasts and inhibition of herpes simplex virus type 1 Kupka by estuarine cyanobacteria extracts.

    PubMed

    Lopes, Viviana R; Schmidtke, Michaela; Helena Fernandes, M; Martins, Rosário; Vasconcelos, Vitor

    2011-06-01

    The cyanobacteria are known to be a rich source of metabolites with a variety of biological activities in different biological systems. In the present work, the bioactivity of aqueous and organic (methanolic and hexane) crude extracts of cyanobacteria isolated from estuarine ecosystems was studied using different bioassays. The assessment of DNA damage on the SOS gene repair region of mutant PQ37 strain of Escherichia coli was performed. Antiviral activity was evaluated against influenza virus, HRV-2, CVB3 and HSV-1 viruses using crystal violet dye uptake on HeLa, MDCK and GMK cell lines. Cytotoxicity evaluation was performed with L929 fibroblasts by MTT assay. Of a total of 18 cyanobacterial isolates studied, only the crude methanolic extract of LEGE 06078 proved to be genotoxic (IF > 1.5) in a dose-dependent manner and other four were putative candidates to induce DNA damage. Furthermore, the crude aqueous extract of LEGE 07085 showed anti- herpes type 1 activity (IC50 = 174.10 μg dry extract mL(-1)) while not presenting any cytotoxic activity against GMK cell lines. Of the 54 cyanobacterial extracts tested, only the crude methanolic and hexane ones showed impair on metabolic activity of L929 fibroblasts after long exposure (48-72 h). The inhibition of HSV-1 and the strong cytotoxicity against L929 cells observed emphasizes the importance of evaluating the impact of those estuarine cyanobacteria on aquatic ecosystem and on human health. The data also point out their potential application in HSV-1 treatment and pharmacological interest. PMID:21396440

  4. 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.

  5. Practical success of biomanipulation using filter-feeding Fish to control cyanobacteria blooms: a synthesis of decades of research and application in a subtropical hypereutrophic lake.

    PubMed

    Xie, P; Liu, J

    2001-08-01

    method has great potential as an important component of an integrated approach to counteract cyanobacteria blooms, especially in lakes where nutrient inputs cannot be reduced sufficiently, and where zooplankton cannot effectively control phytoplankton production. PMID:12806072

  6. Remote estimation of cyanobacteria-dominance in inland waters.

    PubMed

    Shi, Kun; Zhang, Yunlin; Li, Yunmei; Li, Lin; Lv, Heng; Liu, Xiaohan

    2015-01-01

    Remote sensing of the concentration ratio of phycocyanin (PC) to chlorophyll a (Chl-a) is important for water management, as it provides critical knowledge regarding the phytoplankton community. Using the observed in situ datasets, a simple empirical model was developed to estimate PC:Chl-a based on the band ratio index of R(rs)(550R(rs(620) (R(rs-): remote sensing reflectance) (R(2) = 0.84; RMSE = 1.01). This simple model exhibited relatively high validation accuracy using the independent validation dataset. In addition, the model can be successfully applied to AISA (Airborne Imaging Spectrometer for Application) image data, indicating the practicality of the developed model for determining the dominance of cyanobacteria among the total phytoplankton from airborne image data in inland waters. However, the present model cannot be used directly to estimate PC:Chl-a in extremely turbid waters with total suspended matter (TSM) concentrations higher than 25 mg/l. For these waters, the model parameters may require local optimization according to the conditions of the water under analysis. The findings of this study indicate that our proposed model is able to detect the dominance of cyanobacteria among the phytoplankton in inland waters, where the turbidity is not too much high. This study improves our understanding of the species composition of phytoplankton biomass in optically complex inland bodies of water. PMID:25462730

  7. 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

  8. Environmental factors influencing cyanobacteria community structure in Dongping Lake, China.

    PubMed

    Lu, Xuetang; Tian, Chang; Pei, Haiyan; Hu, Wenrong; Xie, Jun

    2013-11-01

    The present study was conducted to provide a detailed understanding of the variation in cyanobacterial communities of Dongping Lake, which is the final water volume adjusting and storing lake in the east route of the South-to-North Water Diversion Project in China. The spatial and temporal distribution of cyanobacteria was assessed from May 2010 to October 2012 based on monthly samples collected from three stations. Over the 30-month survey, 15 genera and 25 species of cyanobacteria were identified, with cyanobacterial abundance at each monitoring station ranging from undetected to 3.04x10(7) cells/L, average of 4.27x10(6) cells/L. The dominant cyanobacterial species were Pseudanabaena limnetica and Aphanizomenon issatschenkoi and not the usual bloom-forming genera such as Microcystis and Anabaena. Cyanobacterial community structure and water quality variables exhibited substantial changes over the period of survey. Redundancy analysis, Pearson correlations, and regression analysis were applied to analyze the relationships among the variables. The results suggested that temperature and chemical oxygen demand were key drivers of the cyanobacterial community composition in Dongping Lake. In addition, the concentration of inorganic nitrogen in the lake had a profound effect on the cyanobacterial abundance as a non-limiting factor in warm periods. PMID:24552047

  9. Intracellular imaging of Qdots-labeled DNA in cyanobacteria.

    PubMed

    Loukanov, Alexandre; Zhelyazkov, Veselin; Hihara, Yukako; Nakabayashi, Seiichiro

    2016-05-01

    In this contribution, they have attempted to develop a labeling technique for in vivo imaging of functionally active plasmid DNA in cyanobacterial cells through its decoration with semiconductor quantum dots (Qdots) as fluorescent nanoprobes. For that purpose biotinylated plasmid slr2060 DNA was conjugated with Qdots-streptavidine. The intact DNA was visualized in a single green color by light microscopy. These Qdots-DNA conjugates were capable of expressing the acyltransferase enzyme. Qdots-DNA conjugates and confocal microscope imaging technique were adopted to visualize the gene transport across the membrane of the live cyanobacteria cell in real time. Long-term kinetic study enabled to reveal the steps of extracellular and intracellular microenvironment for plasmid transportation into the live cell. To confirm these processes a confocal microscope and indicator plate assay test were applied in tandem. In this contribution, Qdots-labeled plasmid DNA was utilized for the first time for long-term intracellular imaging studies in cyanobacteria species PCC6803. The results showed that the Qdots-labeled plasmid DNA detection could be used as a powerful labeling technique for visualization of exogenous DNA entry and tracking into living cells by confocal microscopy. Microsc. Res. Tech. 79:447-452, 2016. © 2016 Wiley Periodicals, Inc. PMID:26957226

  10. Biosorption of nickel in complex aqueous waste streams by cyanobacteria.

    PubMed

    Corder, S L; Reeves, M

    1994-01-01

    A study was undertaken to determined if a suitable biosorbent could be found for removal of nickel at low concentrations (< 20 parts per million [ppm]) from a chemically complex wastewater effluent generated by electroplating operations. Algae and cyanobacteria were chosen as candidate biosorbent materials because they are easy to grow and they have the ability to withstand processing into biosorbent materials. Several species were screened for nickel-biosorption capacity initially, and three species of cyanobacteria were selected for further study based on their performance in the scoping tests. When compared to live controls, autoclaving improved the binding capacities of all three species, but usually biosorption data from experiments with live cells were more consistent. None of the three species was able to bind nickel efficiently in actual effluent samples. Further experimentation indicated that sodium ions, which were present in high concentrations in the effluent, were interfering with the ability of the cells to bind nickel. Adsorption isotherm plots for biosorption of nickel by two species of Anabaena in NiCl2-deionized water solutions were prepared. PMID:8010774

  11. 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

  12. 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

  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. 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

  16. Endosulfan induced biochemical changes in nitrogen-fixing cyanobacteria.

    PubMed

    Kumar, Satyendra; Habib, Khalid; Fatma, Tasneem

    2008-09-15

    Pesticide contamination in aquatic ecosystem including paddy fields is a serious global environmental concern. Cyanobacteria are also affected by pesticides as non- target organism. For better exploitation of cyanobacteria as biofertiliser, it is indispensable to select tolerant strains along with understanding of their tolerance. Three cyanobacterial strains viz. Aulosira fertilissima, Anabaena variabilis and Nostoc muscorum were studied for their stress responses to an organochlorine pesticide 'endosulfan' with special reference to oxidative stress, role of proline and antioxidant enzymes in endosulfan induced free radical detoxification. Reduction in growth, photosynthetic pigments and carbohydrate of the test microorganisms were accompanied with increase in their total protein, proline, malondialdehye (MDA), superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) in higher endosulfan doses. Increased amount of MDA is indicative of formation of free radicals, while increased level of CAT, APX, SOD and proline indicated their involvement in free radical scavenging mechanism. In lower concentrations, test pesticide showed increase in photosynthetic pigments. Order of tolerance was Nostoc muscorum>Anabaena variabilis>Aulosira fertilissima. PMID:18584851

  17. The management of undesirable cyanobacteria blooms in channel catfish ponds using a constructed wetland: Contribution to the control of off-flavor occurrences.

    PubMed

    Zhong, Fei; Gao, Yunni; Yu, Tao; Zhang, Yongyuan; Xu, Dong; Xiao, Enrong; He, Feng; Zhou, Qiaohong; Wu, Zhenbin

    2011-12-01

    An exploratory study on the management of undesirable cyanobacteria blooms with respect to off-flavor problems using an integrated vertical-flow constructed wetland (CW) was performed at a small commercial-scale channel catfish farm from 2004 to 2007. The results of the three-year experiment indicated that water treatment by the CW could reduce the possibility of dominance by undesirable cyanobacteria species that often cause off-flavor problems. A detailed investigation in 2007, showed that the concentrations of geosmin, MIB (2-methylisoborneol), and β-cyclocitral in the water of the recirculating pond (4.3ngL(-1), U.D. (undetected) and 0.2ngL(-1), respectively) treated by the CW were significantly lower than those in the control pond (152.6ngL(-1), 63.3ngL(-1) and 254.8ngL(-1), respectively). In addition, the relationships among the cyanobacteria species, the off-flavor compounds and ten environmental variables were explored by canonical correspondence analysis (CCA). The results showed that Oscillatoria sp., Oscillatoria kawamurae and Microcystis aeruginosa were the main sources of off-flavor compounds in the catfish ponds. The successful manipulation of undesirable cyanobacteria species potentially resulted in lower concentrations of odorous compounds in the water of the recirculating pond. An investigation of the concentrations of geosmin and MIB in catfish fillets showed that the levels of odorous compounds were below the OTC (odor threshold concentration) values in the recirculating pond but were above the OTC values from July to October in the control pond. Water recycling by the CW could potentially be one of the best management practices to control off-flavor occurrences in aquaculture. PMID:22000715

  18. Phylogenetic and Morphological Diversity of Cyanobacteria in Soil Desert Crusts from the Colorado Plateau

    PubMed Central

    Garcia-Pichel, Ferran; López-Cortés, Alejandro; Nübel, Ulrich

    2001-01-01

    We compared the community structures of cyanobacteria in four biological desert crusts from Utah's Colorado Plateau developing on different substrata. We analyzed natural samples, cultures, and cyanobacterial filaments or colonies retrieved by micromanipulation from field samples using microscopy, denaturing gradient gel electrophoresis, and sequencing of 16S rRNA genes. While microscopic analyses apparently underestimated the biodiversity of thin filamentous cyanobacteria, molecular analyses failed to retrieve signals for otherwise conspicuous heterocystous cyanobacteria with thick sheaths. The diversity found in desert crusts was underrepresented in currently available nucleotide sequence databases, and several novel phylogenetic clusters could be identified. Morphotypes fitting the description of Microcoleus vaginatus Gomont, dominant in most samples, corresponded to a tight phylogenetic cluster of probable cosmopolitan distribution, which was well differentiated from other cyanobacteria traditionally classified within the same genus. A new, diverse phylogenetic cluster, named “Xeronema,” grouped a series of thin filamentous Phormidium-like cyanobacteria. These were also ubiquitous in our samples and probably correspond to various botanical Phormidium and Schizothrix spp., but they are phylogenetically distant from thin filamentous cyanobacteria from other environments. Significant differences in community structure were found among soil types, indicating that soil characteristics may select for specific cyanobacteria. Gypsum crusts were most deviant from the rest, while sandy, silt, and shale crusts were relatively more similar among themselves. PMID:11282648

  19. 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. PMID:21691792

  20. Diversity and functional traits of culturable microbiome members, including cyanobacteria in the rice phyllosphere.

    PubMed

    Venkatachalam, S; Ranjan, K; Prasanna, R; Ramakrishnan, B; Thapa, S; Kanchan, A

    2016-07-01

    The diversity and abundance of culturable microbiome members of the rice phyllosphere was investigated using cv. Pusa Punjab Basmati 1509. Both diversity and species richness of bacteria were significantly higher in plants in pots in a semi-controlled environment than those in fields. Application of fertilisers reduced both diversity and species richness in field-grown plants under a conventional flooded system of rice intensification (SRI) and in dry-seeded rice (DSR) modes. Sequence analyses of 16S rDNA of culturable bacteria, those selected after amplified ribosomal DNA restriction analysis (ARDRA), showed the dominance of α-proteobacteria (35%) and actinobacteria (38%); Pantoea, Exiguobacterium and Bacillus were common among the culturable phyllospheric bacteria. About 34% of 83 culturable bacterial isolates had higher potential (>2 μg·ml(-1) ) for indole acetic acid production in the absence of tryptophan. Interestingly, the phyllosphere bacterial isolates from the pot experiment had significantly higher potential for nitrogen fixation than isolates from the field experiment. Enrichment for cyanobacteria showed both unicellular forms and non-heterocystous filaments under aerobic as well as anaerobic conditions. PCR-DGGE analysis of these showed that aerobic and anaerobic conditions as well as the three modes of cultivation of rice in the field strongly influenced the number and abundance of phylotypes. The adaptability and functional traits of these culturable microbiome members suggest enormous diversity in the phyllosphere, including potential for plant growth promotion, which was also significantly influenced by the different methods of growing rice. PMID:26849835

  1. 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

  2. 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. PMID:24507902

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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. PMID:23116182

  8. 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

  9. 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

  10. 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

  11. Metabolic Compensation and Circadian Resilience in Prokaryotic Cyanobacteria

    PubMed Central

    Johnson, Carl Hirschie; Egli, Martin

    2014-01-01

    For a biological oscillator to function as a circadian pacemaker that confers a fitness advantage, its timing functions must be stable in response to environmental and metabolic fluctuations. One such stability enhancer, temperature compensation, has long been a defining characteristic of these timekeepers. However, an accurate biological timekeeper must also resist changes in metabolism, and this review suggests that temperature compensation is actually a subset of a larger phenomenon, namely metabolic compensation, which maintains the frequency of circadian oscillators in response to a host of factors that impinge on metabolism and would otherwise destabilize these clocks. The circadian system of prokaryotic cyanobacteria is an illustrative model because it is composed of transcriptional and nontranscriptional oscillators that are coupled to promote resilience. Moreover, the cyanobacterial circadian program regulates gene activity and metabolic pathways, and it can be manipulated to improve the expression of bioproducts that have practical value. PMID:24905782

  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. 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

  14. Phormidium animalis (Cyanobacteria: Oscillatoriaceae) supports larval development of Anopheles albimanus.

    PubMed

    Vázquez-Martínez, M Guadalupe; Rodríguez, Mario H; Arredondo-Jiménez, Juan I; Méndez-Sánchez, José D

    2003-06-01

    The capability of Phormidium animalis, a cyanobacterium commonly found in larval habitats of Anopheles albimanus in southern Mexico, to support larval development of this mosquito was investigated. First-stage larvae were reared under insectary conditions with P. animalis ad libitum and their development was compared with larvae fed with wheat germ. The time of pupation and adult mosquito size, assessed by wing length, were similar in both groups, but fewer adult mosquitoes were obtained from larvae fed with the cyanobacteria. Nevertheless, these observations indicate that P. animalis is ingested and assimilated by larval An. albimanus, making this cyanobacterium a good candidate for genetic engineering for the introduction of mosquitocidal toxins for malaria control in the region. PMID:12825668

  15. 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

  16. Floating cultivation of marine cyanobacteria using coal fly ash.

    PubMed

    Matsumoto, M; Yoshida, E; Takeyama, H; Matsunaga, T

    2000-01-01

    The aim of this study was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. We have investigated the viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine micro-algae. The marine cyanobacterium Synechococcus sp. NKBG 040607 was found to adhere to floating CFA blocks in liquid culture medium. Maximum density of attached cells of 2.0 x 10(8) cells/cm2 was achieved using seawater. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks. PMID:10849778

  17. 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.

  18. 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

  19. 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...

  20. 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...

  1. 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. PMID:22985108

  2. 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

  3. 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...

  4. Alkane Biosynthesis Genes in Cyanobacteria and Their Transcriptional Organization

    PubMed Central

    Klähn, Stephan; Baumgartner, Desirée; Pfreundt, Ulrike; Voigt, Karsten; Schön, Verena; Steglich, Claudia; Hess, Wolfgang R.

    2014-01-01

    In cyanobacteria, alkanes are synthesized from a fatty acyl-ACP by two enzymes, acyl–acyl carrier protein reductase and aldehyde deformylating oxygenase. Despite the great interest in the exploitation for biofuel production, nothing is known about the transcriptional organization of their genes or the physiological function of alkane synthesis. The comparison of 115 microarray datasets indicates the relatively constitutive expression of aar and ado genes. The analysis of 181 available genomes showed that in 90% of the genomes both genes are present, likely indicating their physiological relevance. In 61% of them they cluster together with genes encoding acetyl-CoA carboxyl transferase and a short-chain dehydrogenase, strengthening the link to fatty acid metabolism and in 76% of the genomes they are located in tandem, suggesting constraints on the gene arrangement. However, contrary to the expectations for an operon, we found in Synechocystis sp. PCC 6803 specific promoters for the two genes, sll0208 (ado) and sll0209 (aar), which give rise to monocistronic transcripts. Moreover, the upstream located ado gene is driven by a proximal as well as a second, distal, promoter, from which a third transcript, the ~160 nt sRNA SyR9 is transcribed. Thus, the transcriptional organization of the alkane biosynthesis genes in Synechocystis sp. PCC 6803 is of substantial complexity. We verified all three promoters to function independently from each other and show a similar promoter arrangement also in the more distant Nodularia spumigena, Trichodesmium erythraeum, Anabaena sp. PCC 7120, Prochlorococcus MIT9313, and MED4. The presence of separate regulatory elements and the dominance of monocistronic mRNAs suggest the possible autonomous regulation of ado and aar. The complex transcriptional organization of the alkane synthesis gene cluster has possible metabolic implications and should be considered when manipulating the expression of these genes in cyanobacteria. PMID

  5. 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.

  6. Phosphoketolase pathway contributes to carbon metabolism in cyanobacteria.

    PubMed

    Xiong, Wei; Lee, Tai-Chi; Rommelfanger, Sarah; Gjersing, Erica; Cano, Melissa; Maness, Pin-Ching; Ghirardi, Maria; Yu, Jianping

    2015-01-01

    Central carbon metabolism in cyanobacteria comprises the Calvin-Benson-Bassham (CBB) cycle, glycolysis, the pentose phosphate (PP) pathway and the tricarboxylic acid (TCA) cycle. Redundancy in this complex metabolic network renders the rational engineering of cyanobacterial metabolism for the generation of biomass, biofuels and chemicals a challenge. Here we report the presence of a functional phosphoketolase pathway, which splits xylulose-5-phosphate (or fructose-6-phosphate) to acetate precursor acetyl phosphate, in an engineered strain of the model cyanobacterium Synechocystis (ΔglgC/xylAB), in which glycogen synthesis is blocked, and xylose catabolism enabled through the introduction of xylose isomerase and xylulokinase. We show that this mutant strain is able to metabolise xylose to acetate on nitrogen starvation. To see whether acetate production in the mutant is linked to the activity of phosphoketolase, we disrupted a putative phosphoketolase gene (slr0453) in the ΔglgC/xylAB strain, and monitored metabolic flux using (13)C labelling; acetate and 2-oxoglutarate production was reduced in the light. A metabolic flux analysis, based on isotopic data, suggests that the phosphoketolase pathway metabolises over 30% of the carbon consumed by ΔglgC/xylAB during photomixotrophic growth on xylose and CO2. Disruption of the putative phosphoketolase gene in wild-type Synechocystis also led to a deficiency in acetate production in the dark, indicative of a contribution of the phosphoketolase pathway to heterotrophic metabolism. We suggest that the phosphoketolase pathway, previously uncharacterized in photosynthetic organisms, confers flexibility in energy and carbon metabolism in cyanobacteria, and could be exploited to increase the efficiency of cyanobacterial carbon metabolism and photosynthetic productivity. PMID:27250745

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. [Identification of cyanobacteria from genus Anabaena isolated from the rhizosphere of cotton-plant].

    PubMed

    Kadyrova, G Kh; Korobkova, E S

    2013-01-01

    Identification of nucleotide sequence of the gene 16S rRNA of cyanobacteria Anabaena variabilis str.21 (Uzb1) exhibits that the strain from root sphere of cotton plants is 99% homologous to a known strain of Anabaena variabilis (EF488831.1). This data confirms the phylogenetic relationship of the strain of cyanobacteria A. variabilis Uzb1 to other described representatives of genus Anabaena as addition to morphological characteristics (presence of akinets (spores) and heterocysts). PMID:23516840

  15. 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

  16. 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

  17. Nitrogen fixation in moss-cyanobacteria associations in boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Rousk, Kathrin

    2014-05-01

    Nitrogen (N) limits the productivity in boreal forests. A major source of 'new' N for these forests is the fixation of atmospheric N2 preformed by cyanobacteria living in association with mosses and lichens. Mosses are a dominant feature in boreal forests, accounting for 60-90% of the groundcover in pristine boreal forests and have been found to be colonized by several N2-fixing cyanobacteria. Given the ubiquitous nature of mosses in these forests, their association with N2-fixing cyanobacteria could characterize the N cycle in these ecosystems. For instance, the feather moss Pleurozium schreberi with its associated cyanobacteria fixes 1-2 kg N ha-1 yr-1, which equals the amount that enters northern boreal forests via atmospheric N deposition. Nitrogen fixation in moss-cyanobacteria associations is affected by numerous abiotic factors that could modulate the N input to the system via the moss-cyanobacteria pathway. For instance, high N availability and dry conditions inhibit N2 fixation in moss-cyanobacteria associations while phosphorus availability and moist conditions promote N2 fixation. Further, N2fixation in moss-cyanobacteria associations is resilient, and can recover from increased N inputs (12 - 15 kg N ha-1 yr-1) as well as from drought stress (moss < 9% field moisture) upon removal of these stressors. Nevertheless, the question as to how important the N2 fixing capability of moss-cyanobacteria associations is as a source of 'new' N for the N cycle in boreal forests remains. For instance, mosses can retain acquired N over long periods of time (> 1 year) and the transfer of N from moss to soil in the short-term has so far only been shown to occur after disturbances (e.g. drying rewetting events, fires). I will present results from laboratory as well as field experiments aimed to elucidate the role moss-cyanobacteria associations play for the N cycle in boreal forests and how abiotic factors control the fixation of atmospheric N2.

  18. 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

  19. 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

  20. 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

  1. A LC/MS method for the determination of cyanobacteria toxins in water.

    PubMed

    Maizels, Mila; Budde, William L

    2004-03-01

    The cyanobacteria toxins anatoxin-a, microcystin-LR, microcystin-RR, microcystin-YR, and nodularin were separated in less than 30 min on several 1 mm x 15 cm reversed-phase liquid chromatography (LC) columns, and their electrospray mass spectra were measured using injections of 50 ng or less with a benchtop time-of-flight (TOF) mass spectrometer. New data from this work include the following: (a) the impact of acetic acid concentrations in the methanol-water mobile phase on measured ion abundances; (b) the performance of the electrospray-TOF mass spectrometer as an LC detector; (c) the accuracy and precision of exact m/z measurements after LC separation with a routinely used mass spectrometer resolving power of 5000; and (d) recoveries of the five toxins from reagent water, river waters, and sewage treatment plant effluent samples extracted with C-18 silica particles enmeshed in thin Teflon membrane filter disks. This technique has the potential of providing a relatively simple and reasonable-cost sample preparation and LC/MS method that provides the sensitivity, selectivity, reliability, and information content needed for source and drinking water occurrence and human exposure studies. PMID:14987091

  2. 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

  3. Stability of microcystins from cyanobacteria--IV. Effect of chlorination on decomposition.

    PubMed

    Tsuji, K; Watanuki, T; Kondo, F; Watanabe, M F; Nakazawa, H; Suzuki, M; Uchida, H; Harada, K

    1997-07-01

    Microcystins, the cyclic heptapeptide toxins produced by cyanobacteria such as Microcystis, show tumor-promoting activity through inhibition of protein phosphatases 1 and 2A. They potentially threaten human health, and are increasing the world-wide interest in the health risk associated with cyanobacterial toxins. In this study, the effect of chlorination on the decomposition of microcystins-LR and -RR was examined. The toxins were easily decomposed by chlorination with sodium hypochlorite, and the decomposition depended on the free chlorine dose. In this operation, many reaction products were formed, one of which was determined to be dihydroxymicrocystin formed through the chloronium ion at the conjugated diene of Adda [3-amino-9-methoxy-10-phenyl-2,6,8-trimethyl-deca-4(E), 6(E)-dienoic acid], followed by hydrolysis. Other products may be its stereoisomers and/or regioismers. No noxious products were detected from the chlorination process of microcystin-LR. Although these results suggested that chlorination at an adequate chlorine dose is very effective for the removal of microcystin in raw water, preoxidation of the cell itself with chlorine must be avoided, because it frequently causes toxin release from algae and produce trihalomethanes during water treatment. PMID:9248002

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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

  9. Bloom-Forming Cyanobacteria Support Copepod Reproduction and Development in the Baltic Sea

    PubMed Central

    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

  10. Genes Associated with 2-Methylisoborneol Biosynthesis in Cyanobacteria: Isolation, Characterization, and Expression in Response to Light

    PubMed Central

    Wang, Zhongjie; Xu, Yao; Shao, Jihai; Wang, Jie; Li, Renhui

    2011-01-01

    The volatile microbial metabolite 2-methylisoborneol (2-MIB) is a root cause of taste and odor issues in freshwater. Although current evidence suggests that 2-MIB is not toxic, this compound degrades water quality and presents problems for water treatment. To address these issues, cyanobacteria and actinomycetes, the major producers of 2-MIB, have been investigated extensively. In this study, two 2-MIB producing strains, coded as Pseudanabaena sp. and Planktothricoids raciborskii, were used in order to elucidate the genetic background, light regulation, and biochemical mechanisms of 2-MIB biosynthesis in cyanobacteria. Genome walking and PCR methods revealed that two adjacent genes, SAM-dependent methyltransferanse gene and monoterpene cyclase gene, are responsible for GPP methylation and subsequent cyclization to 2-MIB in cyanobacteria. These two genes are located in between two homologous cyclic nucleotide-binding protein genes that may be members of the Crp-Fnr regulator family. Together, this sequence of genes forms a putative operon. The synthesis of 2-MIB is similar in cyanobacteria and actinomycetes. Comparison of the gene arrangement and functional sites between cyanobacteria and other organisms revealed that gene recombination and gene transfer probably occurred during the evolution of 2-MIB-associated genes. All the microorganisms examined have a common origin of 2-MIB biosynthesis capacity, but cyanobacteria represent a unique evolutionary lineage. Gene expression analysis suggested that light is a crucial, but not the only, active regulatory factor for the transcription of 2-MIB synthesis genes. This light-regulated process is immediate and transient. This study is the first to identify the genetic background and evolution of 2-MIB biosynthesis in cyanobacteria, thus enhancing current knowledge on 2-MIB contamination of freshwater. PMID:21490938

  11. Report on approaches to predicting probability of cyanobacteria blooms or related indices based on nutrient inputs and other ecosystem attributes in lakes

    EPA Science Inventory

    Despite a lengthy history of research on cyanobacteria, many important questions about this diverse group of aquatic, photosynthetic “blue-green algae” remain unanswered. For example, how can we more accurately predict cyanobacteria blooms in freshwater systems? Whi...

  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. ATP drives direct photosynthetic production of 1-butanol in cyanobacteria

    PubMed Central

    Lan, Ethan I.; Liao, James C.

    2012-01-01

    While conservation of ATP is often a desirable trait for microbial production of chemicals, we demonstrate that additional consumption of ATP may be beneficial to drive product formation in a nonnatural pathway. Although production of 1-butanol by the fermentative coenzyme A (CoA)-dependent pathway using the reversal of β-oxidation exists in nature and has been demonstrated in various organisms, the first step of the pathway, condensation of two molecules of acetyl-CoA to acetoacetyl-CoA, is thermodynamically unfavorable. Here, we show that artificially engineered ATP consumption through a pathway modification can drive this reaction forward and enables for the first time the direct photosynthetic production of 1-butanol from cyanobacteria Synechococcus elongatus PCC 7942. We further demonstrated that substitution of bifunctional aldehyde/alcohol dehydrogenase (AdhE2) with separate butyraldehyde dehydrogenase (Bldh) and NADPH-dependent alcohol dehydrogenase (YqhD) increased 1-butanol production by 4-fold. These results demonstrated the importance of ATP and cofactor driving forces as a design principle to alter metabolic flux. PMID:22474341

  15. 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.

  16. 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).

  17. Systems analysis of the CO2 concentrating mechanism in cyanobacteria

    PubMed Central

    Mangan, Niall M; Brenner, Michael P

    2014-01-01

    Cyanobacteria are photosynthetic bacteria with a unique CO2 concentrating mechanism (CCM), enhancing carbon fixation. Understanding the CCM requires a systems level perspective of how molecular components work together to enhance CO2 fixation. We present a mathematical model of the cyanobacterial CCM, giving the parameter regime (expression levels, catalytic rates, permeability of carboxysome shell) for efficient carbon fixation. Efficiency requires saturating the RuBisCO reaction, staying below saturation for carbonic anhydrase, and avoiding wasteful oxygenation reactions. We find selectivity at the carboxysome shell is not necessary; there is an optimal non-specific carboxysome shell permeability. We compare the efficacy of facilitated CO2 uptake, CO2 scavenging, and HCO3− transport with varying external pH. At the optimal carboxysome permeability, contributions from CO2 scavenging at the cell membrane are small. We examine the cumulative benefits of CCM spatial organization strategies: enzyme co-localization and compartmentalization. DOI: http://dx.doi.org/10.7554/eLife.02043.001 PMID:24842993

  18. 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

  19. 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. PMID:23315747

  20. 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

    2014-01-01

    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. PMID:24675756

  1. 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

  2. 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

  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. PMID:24972068

  4. 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

  5. Bioengineering of carbon fixation, biofuels, and biochemicals in cyanobacteria and plants.

    PubMed

    Rosgaard, Lisa; de Porcellinis, Alice Jara; Jacobsen, Jacob H; Frigaard, Niels-Ulrik; Sakuragi, Yumiko

    2012-11-30

    Development of sustainable energy is a pivotal step towards solutions for today's global challenges, including mitigating the progression of climate change and reducing dependence on fossil fuels. Biofuels derived from agricultural crops have already been commercialized. However the impacts on environmental sustainability and food supply have raised ethical questions about the current practices. Cyanobacteria have attracted interest as an alternative means for sustainable energy productions. Being aquatic photoautotrophs they can be cultivated in non-arable lands and do not compete for land for food production. Their rich genetic resources offer means to engineer metabolic pathways for synthesis of valuable bio-based products. Currently the major obstacle in industrial-scale exploitation of cyanobacteria as the economically sustainable production hosts is low yields. Much effort has been made to improve the carbon fixation and manipulating the carbon allocation in cyanobacteria and their evolutionary photosynthetic relatives, algae and plants. This review aims at providing an overview of the recent progress in the bioengineering of carbon fixation and allocation in cyanobacteria; wherever relevant, the progress made in plants and algae is also discussed as an inspiration for future application in cyanobacteria. PMID:22677697

  6. 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.

  7. 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

  8. Draft Genome Sequence of Limnobacter sp. Strain CACIAM 66H1, a Heterotrophic Bacterium Associated with Cyanobacteria.

    PubMed

    da Silva, Fábio Daniel Florêncio; Lima, Alex Ranieri Jerônimo; Moraes, Pablo Henrique Gonçalves; Siqueira, Andrei Santos; Dall'Agnol, Leonardo Teixeira; Baraúna, Anna Rafaella Ferreira; Martins, Luisa Carício; Oliveira, Karol Guimarães; de Lima, Clayton Pereira Silva; Nunes, Márcio Roberto Teixeira; Vianez-Júnior, João Lídio Silva Gonçalves; Gonçalves, Evonnildo Costa

    2016-01-01

    Ecological interactions between cyanobacteria and heterotrophic prokaryotes are poorly known. To improve the genomic studies of heterotrophic bacterium-cyanobacterium associations, the draft genome sequence (3.2 Mbp) of Limnobacter sp. strain CACIAM 66H1, found in a nonaxenic culture of Synechococcus sp. (cyanobacteria), is presented here. PMID:27198027

  9. Microbial communities on glacier surfaces in Svalbard: impact of physical and chemical properties on abundance and structure of cyanobacteria and algae.

    PubMed

    Stibal, Marek; Sabacká, Marie; Kastovská, Klára

    2006-11-01

    Microbial communities occurring in three types of supraglacial habitats--cryoconite holes, medial moraines, and supraglacial kames--at several glaciers in the Arctic archipelago of Svalbard were investigated. Abundance, biovolume, and community structure were evaluated by using epifluorescence microscopy and culturing methods. Particular emphasis was laid on distinctions in the chemical and physical properties of the supraglacial habitats and their relation to the microbial communities, and quantitative multivariate analyses were used to assess potential relationships. Varying pH (4.8 in cryoconite; 8.5 in a moraine) and texture (the proportion of coarse fraction 2% of dry weight in cryoconite; 99% dw in a kame) were found, and rather low concentrations of organic matter (0.3% of dry weight in a kame; 22% dw in cryoconite) and nutrients (nitrogen up to 0.4% dw, phosphorus up to 0.8% dw) were determined in the samples. In cryoconite sediment, the highest numbers of bacteria, cyanobacteria, and algae were found, whereas relatively low microbial abundances were recorded in moraines and kames. Cyanobacterial cells were significantly more abundant than microalgal ones in cryoconite and supraglacial kames. Different species of the cyanobacterial genus Leptolyngbya were by far the most represented in all samples, and cyanobacteria of the genera Phormidium and Nostoc prevailed in cultures isolated from cryoconite samples. These species are considered opportunistic organisms with wide ecological valency and strong colonizing potential rather than glacial specialists. Statistical analyses suggest that fine sediment with higher water content is the most suitable condition for bacteria, cyanobacteria, and algae. Also, a positive impact of lower pH on microbial growth was found. The fate of a microbial cell deposited on the glacier surface seems therefore predetermined by the physical and chemical factors such as texture of sediment and water content rather than spatial factors

  10. 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). PMID:26408110

  11. PCR primers to amplify 16S rRNA genes from cyanobacteria.

    PubMed Central

    Nübel, U; Garcia-Pichel, F; Muyzer, G

    1997-01-01

    We developed and tested a set of oligonucleotide primers for the specific amplification of 16S rRNA gene segments from cyanobacteria and plastids by PCR. PCR products were recovered from all cultures of cyanobacteria and diatoms that were checked but not from other bacteria and archaea. Gene segments selectively retrieved from cyanobacteria and diatoms in unialgal but nonaxenic cultures and from cyanobionts in lichens could be directly sequenced. In the context of growing sequence databases, this procedure allows rapid and phylogenetically meaningful identification without pure cultures or molecular cloning. We demonstrate the use of this specific PCR in combination with denaturing gradient gel electrophoresis to probe the diversity of oxygenic phototrophic microorganisms in cultures, lichens, and complex microbial communities. PMID:9251225

  12. Evidence for the widespread distribution of CRISPR-Cas system in the Phylum Cyanobacteria

    PubMed Central

    Cai, Fei; Axen, Seth D.; Kerfeld, Cheryl A.

    2013-01-01

    Members of the phylum Cyanobacteria inhabit ecologically diverse environments. However, the CRISPR-Cas (clustered regularly interspaced short palindromic repeats, CRISPR associated genes), an extremely adaptable defense system, has not been surveyed in this phylum. We analyzed 126 cyanobacterial genomes and, surprisingly, found CRISPR-Cas in the majority except the marine subclade (Synechococcus and Prochlorococcus), in which cyanophages are a known force shaping their evolution. Multiple observations of CRISPR loci in the absence of cas1/cas2 genes may represent an early stage of losing a CRISPR-Cas locus. Our findings reveal the widespread distribution of their role in the phylum Cyanobacteria and provide a first step to systematically understanding CRISPR-Cas systems in cyanobacteria. PMID:23628889

  13. Genome Engineering of the 2,3-Butanediol Biosynthetic Pathway for Tight Regulation in Cyanobacteria.

    PubMed

    Nozzi, Nicole E; Atsumi, Shota

    2015-11-20

    Cyanobacteria have gained popularity among the metabolic engineering community as a tractable photosynthetic host for renewable chemical production. However, though a number of successfully engineered production systems have been reported, long-term genetic stability remains an issue for cyanobacterial systems. The genetic engineering toolbox for cyanobacteria is largely lacking inducible systems for expression control. The characterization of tight regulation systems for use in cyanobacteria may help to alleviate this problem. In this work we explore the function of the IPTG inducible promoter P(L)lacO1 in the model cyanobacterium Synechococcus elongatus PCC 7942 as well as the effect of gene order within an operon on pathway expression. According to our experiments, P(L)lacO1 functions well as an inducible promoter in S. elongatus. Additionally, we found that gene order within an operon can strongly influence control of expression of each gene. PMID:25974153

  14. Endolithic Cyanobacteria in Halite Rocks from the Hyperarid Core of the Atacama Desert

    NASA Astrophysics Data System (ADS)

    Wierzchos, Jacek; Ascaso, Carmen; McKay, Christopher P.

    2006-06-01

    In the driest parts of the Atacama Desert there are no visible life forms on soil or rock surfaces. The soil in this region contains only minute traces of bacteria distributed in patches, and conditions are too dry for cyanobacteria that live under translucent stones. Here we show that halite evaporite rocks from the driest part of the Atacama Desert are colonized by cyanobacteria. This colonization takes place just a few millimeters beneath the rock surface, occupying spaces among salt crystals. Our work reveals that these communities are composed of extremely resistant Chroococcidiopsis morphospecies of cyanobacteria and associated heterotrophic bacteria. This newly discovered endolithic environment is an extremely dry and, at the same time, saline microbial habitat. Photosynthetic microorganisms within dry evaporite rocks could be an important and previously unrecognized target for the search for life within our Solar System.

  15. L-amino acid oxidases with specificity for basic L-amino acids in cyanobacteria.

    PubMed

    Gau, Achim E; Heindl, Achim; Nodop, Anke; Kahmann, Uwe; Pistorius, Elfriede K

    2007-01-01

    The two closely related fresh water cyanobacteria Synechococcus elongatus PCC 6301 and Synechococcus elongatus PCC 7942 have previously been shown to constitutively express a FAD-containing L-amino acid oxidase with high specificity for basic L-amino acids (L-arginine being the best substrate). In this paper we show that such an enzyme is also present in the fresh water cyanobacterium Synechococcus cedrorum PCC 6908. In addition, an improved evaluation of the nucleotide/amino acid sequence of the L-amino acid oxidase of Synechococcus elongatus PCC 6301 (encoded by the aoxA gene) with respect to the FAD-binding site and a translocation pathway signal sequence will be given. Moreover, the genome sequences of 24 cyanobacteria will be evaluated for the occurrence of an aoxA-similar gene. In the evaluated cyanobacteria 15 genes encoding an L-amino acid oxidase-similar protein will be found. PMID:17542496

  16. Laboratory observation on culture of cyanobacteria and problem of stromatolites morphogenesis

    NASA Astrophysics Data System (ADS)

    Sumina, Eugenia L.

    2003-01-01

    The laboratory supervision above culture filament cyanobacterias, which form of construction stromatolites, have shown, that at various types of influences in originally homogeneous community (film) from filament cyanobacterias there are allocated structures specific to each kind of influence. It was interpreted as the phenomena having similarities to such processes at more developed organisms, as differentiation and ontogenesis. Proceeding from this, cyanobacterias films was attached the status organism with all complex whole of display of functions, including with function of formation of a skeleton. These data were applied to understanding of nature stromatolites, constructions, when all observable morphological variety of constructions can be explained by the morphological answers of community of filaments to change of the factors of environment.

  17. Expression of organophosphorus-degradation gene ( opd) in aggregating and non-aggregating filamentous nitrogen-fixing cyanobacteria

    NASA Astrophysics Data System (ADS)

    Li, Qiong; Tang, Qing; Xu, Xudong; Gao, Hong

    2010-11-01

    Genetic engineering in filamentous N2-fixing cyanobacteria usually involves Anabaena sp. PCC 7120 and several other non-aggregating species. Mass culture and harvest of such species are more energy consuming relative to aggregating species. To establish a gene transfer system for aggregating species, we tested many species of Anabaena and Nostoc, and identified Nostoc muscorum FACHB244 as a species that can be genetically manipulated using the conjugative gene transfer system. To promote biodegradation of organophosphorus pollutants in aquatic environments, we introduced a plasmid containing the organophosphorus-degradation gene ( opd) into Anabaena sp. PCC 7120 and Nostoc muscorum FACHB244 by conjugation. The opd gene was driven by a strong promoter, P psbA . From both species, we obtained transgenic strains having organophosphorus-degradation activities. At 25°C, the whole-cell activities of the transgenic Anabaena and Nostoc strains were 0.163±0.001 and 0.289±0.042 unit/μg Chl a, respectively. However, most colonies resulting from the gene transfer showed no activity. PCR and DNA sequencing revealed deletions or rearrangements in the plasmid in some of the colonies. Expression of the green fluorescent protein gene from the same promoter in Anabaena sp. PCC 7120 showed similar results. These results suggest that there is the potential to promote the degradation of organophosphorus pollutants with transgenic cyanobacteria and that selection of high-expression transgenic colonies is important for genetic engineering of Anabaena and Nostoc species. For the first time, we established a gene transfer and expression system in an aggregating filamentous N2-fixing cyanobacterium. The genetic manipulation system of Nostoc muscorum FACHB244 could be utilized in the elimination of pollutants and large-scale production of valuable proteins or metabolites.

  18. Effect of oxidant exposure on the release of intracellular microcystin, MIB, and geosmin from three cyanobacteria species.

    PubMed

    Wert, Eric C; Korak, Julie A; Trenholm, Rebecca A; Rosario-Ortiz, Fernando L

    2014-04-01

    The release of intracellular microcystin-LR (MC-LR), 2-methylisoborneol (MIB), and geosmin was investigated after the oxidation of three cyanobacteria (Microcystis aeruginosa (MA), Oscillatoria sp. (OSC), and Lyngbya sp. (LYN)). During the oxidation of 200,000 cells/mL of MA, release of intracellular MC-LR exceeded the World Health Organization (WHO) guideline of 1 μg/L during the lowest oxidant exposures (CT) tested: ozone (0 mg-min/L, below the ozone demand), chlorine (<40 mg-min/L), chlorine dioxide (<560 mg-min/L), and chloramine (<640 mg-min/L). As the CT increased, ozone, chlorine, and chlorine dioxide were able to oxidize the released MC-LR. During the oxidation of OSC (2800 cells/mL) and LYN (1600 cells/mL), release of intracellular MIB and geosmin exceeded reported threshold odor values after exposure to chlorine, chlorine dioxide, and chloramine, which have low reactivity with these taste and odor compounds. Ozone oxidation of OSC yielded an increase in MIB concentration at lower exposures (≤2.9 mg-min/L), likely due to insufficient oxidation by hydroxyl radicals. The release of intracellular organic matter (IOM) was also measured to determine the potential of bulk measurements to act as a surrogate for cyanotoxins and metabolite release. In all cases, the dissolved organic carbon (DOC) release was less than 0.25 mgC/L, which lacked the sensitivity to indicate the release of MC-LR, MIB, or geosmin. The fluorescence index proved to be a more sensitive indicator of intracellular organic matter release than DOC for MA. These results illustrate that toxic or odorous compounds may be released from cyanobacteria cells during oxidation processes with minimal changes in the DOC concentration. PMID:24289950

  19. The enrichment of biomass of cyanobacteria with vanadium using the cation and anion forms of its compounds.

    PubMed

    Vasilieva, Svetlana Gennadievna; Tambiev, Alexander Khapachevich; Sedykh, Ivelina Maximovna; Lukyanov, Alexander Andrievich; Bannikh, Lidia Nicolaevna

    2011-04-01

    Compounds of the trace element vanadium have been shown to mimic insulin effects in in vitro and in vivo systems. Vanadium compounds have emerged as agents for potential use in diabetes therapy. In our work we show the possibility of obtaining enriched biomass of cyanobacteria genus Spirulina (S. platensis and S. maxima) with vanadium in organic form. We have investigated the accumulation of vanadium by the cells of cyanobacteria S. platensis and S. maxima by adding to cultural medium both the forms of vanadium in various concentrations and have defined the optimal concentrations of vanadium in the medium for maximum enrichment of the cells. We defined that S. maxima is more steady to increased concentration of vanadium(IV) and (V) in medium. Optimal concentration of vanadium(IV) in the medium for enrichment of S. platensis and S. maxima biomass was 1.5 g/L, at this vanadium concentration in medium the content of vanadium in the cells of S. platensis was 1245±105 μg/g and in the cells of S. maxima was 1550±75 μg/g. In the case of vanadium(V) addition, the optimal concentration for S. platensis enrichment was 1.5 g/L vanadium(V) in medium, and the intracellular concentration was 2855±254 μg/g. For S. maxima the optimal concentration was 1.0 g/L vanadium(V) in medium, at that concentration the content of vanadium in cells was 2650±206 μg/g. In addition, we revealed the alterations in macro- and microelemental compositions of both cultures caused by the increased concentration of vanadium compounds in cultural medium. PMID:21514809

  20. Surveying DNA Elements within Functional Genes of Heterocyst-Forming Cyanobacteria

    PubMed Central

    Hilton, Jason A.; Meeks, John C.; Zehr, Jonathan P.

    2016-01-01

    Some cyanobacteria are capable of differentiating a variety of cell types in response to environmental factors. For instance, in low nitrogen conditions, some cyanobacteria form heterocysts, which are specialized for N2 fixation. Many heterocyst-forming cyanobacteria have DNA elements interrupting key N2 fixation genes, elements that are excised during heterocyst differentiation. While the mechanism for the excision of the element has been well-studied, many questions remain regarding the introduction of the elements into the cyanobacterial lineage and whether they have been retained ever since or have been lost and reintroduced. To examine the evolutionary relationships and possible function of DNA sequences that interrupt genes of heterocyst-forming cyanobacteria, we identified and compared 101 interruption element sequences within genes from 38 heterocyst-forming cyanobacterial genomes. The interruption element lengths ranged from about 1 kb (the minimum able to encode the recombinase responsible for element excision), up to nearly 1 Mb. The recombinase gene sequences served as genetic markers that were common across the interruption elements and were used to track element evolution. Elements were found that interrupted 22 different orthologs, only five of which had been previously observed to be interrupted by an element. Most of the newly identified interrupted orthologs encode proteins that have been shown to have heterocyst-specific activity. However, the presence of interruption elements within genes with no known role in N2 fixation, as well as in three non-heterocyst-forming cyanobacteria, indicates that the processes that trigger the excision of elements may not be limited to heterocyst development or that the elements move randomly within genomes. This comprehensive analysis provides the framework to study the history and behavior of these unique sequences, and offers new insight regarding the frequency and persistence of interruption elements in

  1. Irreversible Collective Migration of Cyanobacteria in Eutrophic Conditions

    PubMed Central

    Dervaux, Julien; Mejean, Annick; Brunet, Philippe

    2015-01-01

    In response to natural or anthropocentric pollutions coupled to global climate changes, microorganisms from aquatic environments can suddenly accumulate on water surface. These dense suspensions, known as blooms, are harmful to ecosystems and signicantly degrade the quality of water resources. In order to determine the physico-chemical parameters involved in their formation and quantitatively predict their appearance, we successfully reproduced irreversible cyanobacterial blooms in vitro. By combining chemical, biochemical and hydrodynamic evidences, we identify a mechanism, unrelated to the presence of internal gas vesicles, allowing the sudden collective upward migration in test tubes of several cyanobacterial strains (Microcystis aeruginosa PCC 7005, Microcystis aeruginosa PCC 7806 and Synechocystis sp. PCC 6803). The final state consists in a foamy layer of biomass at the air-liquid interface, in which micro-organisms remain alive for weeks, the medium lying below being almost completely depleted of cyanobacteria. These "laboratory blooms" start with the aggregation of cells at high ionic force in cyanobacterial strains that produce anionic extracellular polymeric substances (EPS). Under appropriate conditions of nutrients and light intensity, the high photosynthetic activity within cell clusters leads the dissolved oxygen (DO) to supersaturate and to nucleate into bubbles. Trapped within the EPS, these bubbles grow until their buoyancy pulls the biomass towards the free surface. By investigating a wide range of spatially homogeneous environmental conditions (illumination, salinity, cell and nutrient concentration) we identify species-dependent thresholds and timescales for bloom formation. We conclude on the relevance of such results for cyanobacterial bloom formation in the environment and we propose an ecient method for biomass harvesting in bioreactors. PMID:25799424

  2. Comparative characterization of novel ene-reductases from cyanobacteria.

    PubMed

    Fu, Yilei; Castiglione, Kathrin; Weuster-Botz, Dirk

    2013-05-01

    The growing importance of biocatalysis in the syntheses of enantiopure molecules results from the benefits of enzymes regarding selectivity and specificity of the reaction and ecological issues of the process. Ene-reductases (ERs) from the old yellow enzyme family have received much attention in the last years. These flavo-enzymes catalyze the trans-specific reduction of activated C=C bonds, which is an important reaction in asymmetric synthesis, because up to two stereogenic centers can be created in one reaction. However, limitations of ERs described in the literature such as their moderate catalytic activity and their strong preference for NADPH promote the search for novel ERs with improved properties. In this study, we characterized nine novel ERs from cyanobacterial strains belonging to different taxonomic orders and habitats. ERs were identified with activities towards a broad spectrum of alkenes. The reduction of maleimide was catalyzed with activities of up to 35.5 U mg(-1) using NADPH. Ketoisophorone and (R)-carvone, which were converted to the highly valuable compounds (R)-levodione and (2R,5R)-dihydrocarvone, were reduced with reaction rates of up to 2.2 U mg(-1) with NADPH. In contrast to other homologous ERs from the literature, NADH was accepted at moderate to high rates as well: Enzyme activities of up to 16.7 U mg(-1) were obtained for maleimide and up to 1.3 U mg(-1) for ketoisophorone and (R)-carvone. Additionally, excellent stereoselectivities were achieved in the reduction of (R)-carvone (97-99% de). In particular, AnabaenaER3 from Anabaena variabilis ATCC 29413 and AcaryoER1 from Acaryochloris marina MBIC 11017 were identified as useful biocatalysts. Therefore, novel ERs from cyanobacteria with high catalytic efficiency were added to the toolbox for the asymmetric reduction of alkenes. PMID:23280373

  3. Hyperspectral remote sensing of Cyanobacteria: successes and challenges

    NASA Astrophysics Data System (ADS)

    Mishra, Deepak R.; Mishra, Sachidananda; Narumalani, Sunil

    2014-11-01

    Cyanobacterial harmful algal blooms (CHABs) is a major water quality issue in surface water bodies because of its scum and bad odor forming and toxin producing abilities. Terminations of blooms also cause oxygen depletion leading to hypoxia and widespread fish kills. Therefore, continuous monitoring of CHABs in recreational water bodies and surface drinking water sources is highly required for their early detection and subsequent issuance of a health warning and reducing the economic loss. We present a comparative study between a modified quasi-analytical algorithm (QAA) and a novel three-band algorithm (PC3) to retrieve phycocyanin (PC) pigment concentration in cyanobacteria laden inland waters. An extensive dataset, consisting of radiometric measurements, absorption measurements of phytoplankton, organic matter, detritus, and pigment concentration, was used to optimize the algorithms. The QAA algorithm isolates the PC signal from the remote sensing reflectance data using a set of radiative transfer equations and retrieves PC concentration in the water bodies through bio-optical inversion. Validation of the QAA algorithm, using an independent dataset, produced a mean relative error (MRE) of 34%. For the PC3 algorithm, we propose a coefficient (ψ) for isolating the PC absorption component at 620 nm. Results show that inclusion of the model coefficient relating chlorophyll-a (chla) absorption at 620 nm to 665 nm enables PC3 to compensate for the confounding effect of chl-a and considerably increases the accuracy of the PC prediction algorithm. The MRE of prediction for PC3 was 27%. Moreover, PC3 eliminates the nonlinear sensitivity issue of PC algorithms at high range.

  4. Stable Isotope Evidence of Variation in Nitrogen Fixation by Cyanobacteria in Coastal Ecosystems

    NASA Astrophysics Data System (ADS)

    Paul, V.; Clementz, M.

    2006-12-01

    Increased nutrient loading via both natural and anthropogenic factors has been reported as one possible mechanism for the recent increase in the occurrence and intensity of harmful algal blooms (HAB) in coastal ecosystems. Influx of iron, phosphorous, and organic carbon have proven to be significant stimulating factors for HAB, since the benthic cyanobacteria that often make up these blooms are capable of nitrogen-fixation and require these nutrients for this process as well as photosynthesis. These cyanobacteria can switch to direct uptake of dissolved inorganic nitrogen (DIN), however, when concentrations are high enough to energetically favor this source, suggesting that high nitrogen input may also stimulate HAB. Given the distinct isotope differences between atmospheric N2 (0‰) and anthropogenic sources of DIN (>6‰), measurement of the δ15N composition of cyanobacteria can provide a means of gauging the relative significance of anthropogenic versus atmospheric nitrogen to the growth of these blooms. Likewise, the δ13C composition of these primary producers is controlled by the δ13C composition of the DIC, and can be a second tracer of anthropogenic influx into marine ecosystems. A combined approach using both isotope tracers was employed to determine the significance of anthropogenic nitrogen on HAB in subtropical/tropical coastal marine ecosystems. Samples of cyanobacteria and associated macroalgae were collected from three coastal sites in Guam (Facpi Point, Tanguisson, and Ypao Beach), one locality in Hawaii, and three sites in southern Florida (Pepper Park, Fort Lauderdale, Florida Keys). Following removal of marine carbonates via an acid rinse, the δ13C and δ15N values were determined for each species. Cyanobacterial δ15N values ranged from -2.3‰ to 7.7‰ with the highest values reported from sites in Guam. Only cyanobacteria sampled from Hawaii showed no isotope evidence of an anthropogenic source for nitrogen. A strong negative correlation

  5. [Use of associative cultures of cyanobacteria for tertiary treatment of sewage from yeast and alcohol plants].

    PubMed

    Koshel', M I; Zabolotna, G M; Kovyrzina, T V; Mendzhul, M I; Koltukova, N V

    2001-01-01

    The associative cultures of cyanobacteria were selected which may be used for development of technology of tertiary treatment of sewage for yeast and alcohol production plants. Growth parameters of associations were studied during periodic and continuous cultivation. When studying the influence of flowing speed for some exponents of treatment it was shown that cultivation of cyanobacteria should be carried out with the change of volume not more than 0.01 h. Final treatment 0.010 h-1 in order to return sewage to natural water reservoirs may be carried out by means of Oscillatoria sp. in bioponds. PMID:11785265

  6. Cylindrospermopsis raciborskii (Cyanobacteria) exudates: chemical characterization and complexation capacity for Cu, Zn, Cd and Pb.

    PubMed

    Tonietto, Alessandra Emanuele; Lombardi, Ana Teresa; Vieira, Armando Augusto Henriques; Parrish, Christopher C; Choueri, Rodrigo Brasil

    2014-02-01

    Cylindrospermopsis raciborskii is a cosmopolitan and potentially toxic planktonic Cyanobacteria that produces and exudes copious amounts of dissolved organic materials. This organism dominates the eutrophic reservoir Barra Bonita (Brazil), where it normally blooms throughout the year. This investigation focused on the characterization of such exudates analyzing their capacity to complex copper, zinc, lead and cadmium through the determination of ligand concentration (CL) and conditional stability constant (logK'ML), as well as elemental composition (C, H, N and S), the content of carbohydrates, proteins, lipids and dissolved organic carbon (DOC). The dissolved organic material was fractionated into 3 molecular weights (>30 kDa; 30-10 kDa; 10-3 kDa) and each fraction was analyzed. The results showed that in the >30 kDa and 30-10 kDa fractions carbohydrates dominate over proteins and lipids. Different CL and logK'ML were obtained for the different molecular weight fractions of the excreted organic materials, suggesting high diversity of ligands. In the >30 kDa, there were more complexing sites (CL) for Cu, but higher affinity (K') for Zn. In the 30-10 kDa fraction, the higher CL was for Cd, but the greatest affinities were for Cu and Zn. In the 10-3 kDa fraction, higher CL was obtained for Cd and Zn, while Cu and Cd had the highest strengths of association. In the environment, such diversity of ligands and strengths of association can result in a displacement of metals weakly bound to the EOM, and increase metal buffering capacity of the environment, supporting higher metal inputs before toxic effects are detected in the biota. PMID:24169513

  7. Anthropogenic CO2 as a Feedstock for Cyanobacteria-Based Biofuels

    NASA Astrophysics Data System (ADS)

    Chance, Ronald

    2015-04-01

    Biofuels have great potential as low-carbon alternatives to fossil-based transportation fuels, and can serve as drop-in fuels for existing transportation infrastructures. This talk will focus on utilization of anthropogenic CO2 in an advanced biofuel system and the integration of that system with fossil-fuel power plants. The biofuel system is the Algenol Direct to Ethanol® technology, which provides an efficient, cyanobacteria-based system for producing ethanol, as well as a bio-crude co-product. The talk will begin with an overview of the Algenol technology: the genetic enhancement approach for enabling ethanol production in the organisms; ethanol and biomass production in outdoor cultures contained in large photobioreactor arrays; downstream processing systems; and phenomenological productivity modeling in terms of quantum yields, photo-saturation effects, respiration, and carbon partitioning. Overall, the results are consistent with a very efficient photosynthetic system in which more than 75% of the photosynthetically fixed carbon is diverted into the ethanol production pathway. The Algenol process consumes CO2 in a solar energy conversion process that yields a biofuel with much lower greenhouse gas emissions than gasoline. Different options for CO2 capture and utilization are considered and their impact on the overall system operation evaluated. Comparisons of life-cycle carbon footprints are made for the Algenol technology versus other transportation fuel options, including electric vehicles. Finally, we expand the boundary of the life cycle analysis to include the power plant, specifically considering natural gas and three coal-based options, and compare carbon footprints for the integrated systems to CCS (carbon capture and sequestration) as well as to the status quo of CO2 release to the atmosphere.

  8. Alternative pathways for phosphonate metabolism in thermophilic cyanobacteria from microbial mats

    PubMed Central

    Gomez-Garcia, Maria R; Davison, Michelle; Blain-Hartnung, Matthew; Grossman, Arthur R; Bhaya, Devaki

    2011-01-01

    Synechococcus sp. represents an ecologically diverse group of cyanobacteria found in numerous environments, including hot-spring microbial mats, where they are spatially distributed along thermal, light and oxygen gradients. These thermophiles engage in photosynthesis and aerobic respiration during the day, but switch to fermentative metabolism and nitrogen fixation at night. The genome of Synechococcus OS-B′, isolated from Octopus Spring (Yellowstone National Park) contains a phn gene cluster encoding a phosphonate (Phn) transporter and a C–P lyase. A closely related isolate, Synechococcus OS-A, lacks this cluster, but contains genes encoding putative phosphonatases (Phnases) that appear to be active only in the presence of the Phn substrate. Both isolates grow well on several different Phns as a sole phosphorus (P) source. Interestingly, Synechococcus OS-B′ can use the organic carbon backbones of Phns for heterotrophic growth in the dark, whereas in the light this strain releases organic carbon from Phn as ethane or methane (depending on the specific Phn available); Synechococcus OS-A has neither of these capabilities. These differences in metabolic strategies for assimilating the P and C of Phn by two closely related Synechococcus spp. are suggestive of niche-specific constraints in the evolution of nutrient assimilation pathways and syntrophic relationships among the microbial populations of the hot-spring mats. Thus, it is critical to evaluate levels of various P sources, including Phn, in thermally active habitats and the potential importance of these compounds in the biogeochemical cycling of P and C (some Phn compounds also contain N) in diverse terrestrial environments. PMID:20631809

  9. Phylogeography of Cylindrospermopsin and Paralytic Shellfish Toxin-Producing Nostocales Cyanobacteria from Mediterranean Europe (Spain)

    PubMed Central

    Cirés, Samuel; Wörmer, Lars; Ballot, Andreas; Agha, Ramsy; Wiedner, Claudia; Velázquez, David; Casero, María Cristina

    2014-01-01

    Planktonic Nostocales cyanobacteria represent a challenge for microbiological research because of the wide range of cyanotoxins that they synthesize and their invasive behavior, which is presumably enhanced by global warming. To gain insight into the phylogeography of potentially toxic Nostocales from Mediterranean Europe, 31 strains of Anabaena (Anabaena crassa, A. lemmermannii, A. mendotae, and A. planctonica), Aphanizomenon (Aphanizomenon gracile, A. ovalisporum), and Cylindrospermopsis raciborskii were isolated from 14 freshwater bodies in Spain and polyphasically analyzed for their phylogeography, cyanotoxin production, and the presence of cyanotoxin biosynthesis genes. The potent cytotoxin cylindrospermopsin (CYN) was produced by all 6 Aphanizomenon ovalisporum strains at high levels (5.7 to 9.1 μg CYN mg−1 [dry weight]) with low variation between strains (1.5 to 3.9-fold) and a marked extracellular release (19 to 41% dissolved CYN) during exponential growth. Paralytic shellfish poisoning (PSP) neurotoxins (saxitoxin, neosaxitoxin, and decarbamoylsaxitoxin) were detected in 2 Aphanizomenon gracile strains, both containing the sxtA gene. This gene was also amplified in non-PSP toxin-producing Aphanizomenon gracile and Aphanizomenon ovalisporum. Phylogenetic analyses supported the species identification and confirmed the high similarity of Spanish Anabaena and Aphanizomenon strains with other European strains. In contrast, Cylindrospermopsis raciborskii from Spain grouped together with American strains and was clearly separate from the rest of the European strains, raising questions about the current assumptions of the phylogeography and spreading routes of C. raciborskii. The present study confirms that the nostocalean genus Aphanizomenon is a major source of CYN and PSP toxins in Europe and demonstrates the presence of the sxtA gene in CYN-producing Aphanizomenon ovalisporum. PMID:24334673

  10. Alternative pathways for phosphonate metabolism in thermophilic cyanobacteria from microbial mats.

    PubMed

    Gomez-Garcia, Maria R; Davison, Michelle; Blain-Hartnung, Matthew; Grossman, Arthur R; Bhaya, Devaki

    2011-01-01

    Synechococcus sp. represents an ecologically diverse group of cyanobacteria found in numerous environments, including hot-spring microbial mats, where they are spatially distributed along thermal, light and oxygen gradients. These thermophiles engage in photosynthesis and aerobic respiration during the day, but switch to fermentative metabolism and nitrogen fixation at night. The genome of Synechococcus OS-B', isolated from Octopus Spring (Yellowstone National Park) contains a phn gene cluster encoding a phosphonate (Phn) transporter and a C-P lyase. A closely related isolate, Synechococcus OS-A, lacks this cluster, but contains genes encoding putative phosphonatases (Phnases) that appear to be active only in the presence of the Phn substrate. Both isolates grow well on several different Phns as a sole phosphorus (P) source. Interestingly, Synechococcus OS-B' can use the organic carbon backbones of Phns for heterotrophic growth in the dark, whereas in the light this strain releases organic carbon from Phn as ethane or methane (depending on the specific Phn available); Synechococcus OS-A has neither of these capabilities. These differences in metabolic strategies for assimilating the P and C of Phn by two closely related Synechococcus spp. are suggestive of niche-specific constraints in the evolution of nutrient assimilation pathways and syntrophic relationships among the microbial populations of the hot-spring mats. Thus, it is critical to evaluate levels of various P sources, including Phn, in thermally active habitats and the potential importance of these compounds in the biogeochemical cycling of P and C (some Phn compounds also contain N) in diverse terrestrial environments. PMID:20631809

  11. Microwhip Scorpions (Palpigradi) Feed on Heterotrophic Cyanobacteria in Slovak Caves – A Curiosity among Arachnida

    PubMed Central

    Smrž, Jaroslav; Kováč, Ĺubomír; Mikeš, Jaromír; Lukešová, Alena

    2013-01-01

    To date, only morphological and anatomical descriptions of microwhip scorpions (Arachnida: Palpigradi) have been published. This very rare group is enigmatic not only in its relationships to other arachnids, but especially due to the fact that these animals dwell only underground (in caves, soil, and interstitial spaces). We observed the curious feeding habit of the microwhip scorpion Eukoenenia spelaea over the course of one year in Ardovská Cave, located in Slovakia's Karst region. We chose histology as our methodology in studying 17 specimens and based it upon Masson's triple staining, fluorescent light and confocal microscopy. Single-celled cyanobacteria (blue-green algae) were conspicuously predominant in the gut of all studied palpigrades. Digestibility of the consumed cyanobacteria was supported by the presence of guanine crystals, glycogen deposits and haemocytes inside the palpigrade body. Cyanobacteria, the oldest cellular organisms on Earth, are very resistant to severe conditions in caves, including even darkness. Therefore, the cyanobacteria are able to survive in dark caves as nearly heterotrophic organisms and are consumed by cave palpigrades. Such feeding habit is extraordinary within the almost wholly predacious orders of the class Arachnida, and particularly so due to the type of food observed. PMID:24146804

  12. PHYTOPLANKTON AND ZOOPLANKTON SEASONAL DYNAMICS IN A SUBTROPICAL ESTUARY: IMPORTANCE OF CYANOBACTERIA

    EPA Science Inventory

    Murrell, Michael C. and Emile M. Lores. 2004. Phytoplankton and Zooplankton Seasonal Dynamics in a Subtropical Estuary: Importance of Cyanobacteria. J. Plankton Res. 26(3):371-382. (ERL,GB 1190).

    A seasonal study of phytoplankton and zooplankton was conducted from 1999-20...

  13. A LC/MS METHOD FOR THE DETERMINATION OF CYANOBACTERIA TOXINS IN WATER

    EPA Science Inventory

    The cyanobacteria toxins anatoxin-a, microcystin-LR, microcystin-RR, microcystin-YR, and nodularin were separated in less than 30 minutes on several 1 mm x 15 cm reverse phase liquid chromatography (LC) columns, and their electrospray mass spectra were measured with 50 ng or less...

  14. Draft genome sequence of cyanobacteria Arthrospira sp. TJSD091 isolated from seaside wetland.

    PubMed

    Dong, Shirui; Chen, Jin; Wang, Suying; Wu, Yuemei; Hou, Hujing; Li, Mi; Yan, Chunyu

    2015-12-01

    The cyanobacteria TJSD091 strain, a member of the genus Arthrospira was isolated from seaside wetland in China, Bohai. The draft genome sequence of Arthrospira sp. TJSD091 with a genome size of approximately 6.3 Mbp and a G+C content of 44.75% is reported. PMID:26001511

  15. The Role of Endolithic Cyanobacteria in the Formation of Lithified Laminae in Bahamian Stromatolites

    NASA Technical Reports Server (NTRS)

    Prufert-Bebout, L.; Macintyre, I.; Reid, R. P.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The microboring activity of endolithic cyanobacteria plays a major role in the formation of lithified laminae in modern marine stromatolites in the Exuma Cays, Bahamas. These stromatolites are composed primarily of fine grained carbonate sand that is trapped and bound by the filamentous cyanobacteria Schizothrix sp. Periodic introduction of coccoid endolithic cyanobacteria, Solentia sp., results in formation of lithified horizons, 200 to 1000 micron thick. We used SEM and petrographic analyses to examine both naturally occurring lithified layers dominated by endoliths and fused oolitic crusts generated in the laboratory by activity of endolithic cyanobacteria (Solentia sp.). Fused grain crusts consist of micritized grains that are welded together at point contacts. Micritization results from extensive microboring and rapid (days to weeks) carbonate precipitation within the bore holes. This precipitation appears to occur concurrently with further endolithic activity within the grain, Infilling of bore holes that cross from one grain to another at point contacts results in grain welding, Thus, while microboring destroys original grain textures, at the same time the endolith activity plays a constructional role in stromatolite growth by forming lithified layers of welded grains. These framework structures help to stabilize and preserve the stromatolite deposits.

  16. Absence of sterols constrains carbon transfer between cyanobacteria and a freshwater herbivore (Daphnia galeata).

    PubMed Central

    von Elert, Eric; Martin-Creuzburg, Dominik; Le Coz, Jean R

    2003-01-01

    A key process in freshwater plankton food webs is the regulation of the efficiency of energy and material transfer. Cyanobacterial carbon (C) in particular is transferred very inefficiently to herbivorous zooplankton, which leads to a decoupling of primary and secondary production and the accumulation of cyanobacterial biomass, which is associated with reduced recreational quality of water bodies and hazards to human health. A recent correlative field study suggested that the low transfer efficiency of cyanobacterial C is the result of the absence of long-chain polyunsaturated fatty acids (PUFA) in the diet of the zooplankton. By supplementation of single-lipid compounds in controlled growth experiments, we show here that the low C transfer efficiency of coccal and filamentous cyanobacteria to the keystone herbivore Daphnia is caused by the low sterol content in cyanobacteria, which constrains cholesterol synthesis and thereby growth and reproduction of the herbivore. Estimations of sterol requirement in Daphnia suggest that, when cyanobacteria comprise more than 80% of the grazed phytoplankton, growth of the herbivore may be limited by sterols and Daphnia may subsequently fail to control phytoplankton biomass. Dietary sterols therefore may play a key role in freshwater food webs and in the control of water quality in lakes dominated by cyanobacteria. PMID:12816661

  17. Metals in Cyanobacteria: Analysis of the Copper, Nickel, Cobalt and Arsenic Homeostasis Mechanisms

    PubMed Central

    Huertas, María José; López-Maury, Luis; Giner-Lamia, Joaquín; Sánchez-Riego, Ana María; Florencio, Francisco Javier

    2014-01-01

    Traces of metal are required for fundamental biochemical processes, such as photosynthesis and respiration. Cyanobacteria metal homeostasis acquires an important role because the photosynthetic machinery imposes a high demand for metals, making them a limiting factor for cyanobacteria, especially in the open oceans. On the other hand, in the last two centuries, the metal concentrations in marine environments and lake sediments have increased as a result of several industrial activities. In all cases, cells have to tightly regulate uptake to maintain their intracellular concentrations below toxic levels. Mechanisms to obtain metal under limiting conditions and to protect cells from an excess of metals are present in cyanobacteria. Understanding metal homeostasis in cyanobacteria and the proteins involved will help to evaluate the use of these microorganisms in metal bioremediation. Furthermore, it will also help to understand how metal availability impacts primary production in the oceans. In this review, we will focus on copper, nickel, cobalt and arsenic (a toxic metalloid) metabolism, which has been mainly analyzed in model cyanobacterium Synechocystis sp. PCC 6803. PMID:25501581

  18. Metals in cyanobacteria: analysis of the copper, nickel, cobalt and arsenic homeostasis mechanisms.

    PubMed

    Huertas, María José; López-Maury, Luis; Giner-Lamia, Joaquín; Sánchez-Riego, Ana María; Florencio, Francisco Javier

    2014-01-01

    Traces of metal are required for fundamental biochemical processes, such as photosynthesis and respiration. Cyanobacteria metal homeostasis acquires an important role because the photosynthetic machinery imposes a high demand for metals, making them a limiting factor for cyanobacteria, especially in the open oceans. On the other hand, in the last two centuries, the metal concentrations in marine environments and lake sediments have increased as a result of several industrial activities. In all cases, cells have to tightly regulate uptake to maintain their intracellular concentrations below toxic levels. Mechanisms to obtain metal under limiting conditions and to protect cells from an excess of metals are present in cyanobacteria. Understanding metal homeostasis in cyanobacteria and the proteins involved will help to evaluate the use of these microorganisms in metal bioremediation. Furthermore, it will also help to understand how metal availability impacts primary production in the oceans. In this review, we will focus on copper, nickel, cobalt and arsenic (a toxic metalloid) metabolism, which has been mainly analyzed in model cyanobacterium Synechocystis sp. PCC 6803. PMID:25501581

  19. Genetic diversity and phylogeny of toxic cyanobacteria determined by DNA polymorphisms within the phycocyanin locus.

    PubMed Central

    Neilan, B A; Jacobs, D; Goodman, A E

    1995-01-01

    Cyanobacteria are a highly diverse group in relation to form, function, and habitat. Current cyanobacterial systematics relies on the observation of minor and plastic morphological characters. Accurate and reliable delineation of toxic and bloom-forming strains of cyanobacteria has not been possible by traditional methods. We have designed general primers to the phycocyanin operon (cpc gene) and developed a PCR which allows the amplification of a region of this gene, including a variable intergenic spacer sequence. Because of the specificity of this PCR for cyanobacterial isolates, the assay is appropriate for the rapid and reliable identification of strains in freshwater samples. Successive restriction endonuclease digestion of this amplification product, with a total of nine enzymes, yielded many identifying DNA profiles specific to the various taxonomic levels of cyanobacteria. The restriction enzyme profiles for MspI, RsaI, and TaqI were conserved for strains within each of the eight genera (40 strains) studied and clearly discriminated among these genera. Intrageneric delineation of strains was revealed by the enzymes AluI, CfoI, and HaeIII for members of the genus Microcystis, while strains of genus Anabaena were differentiated by the digestion patterns provided by AluI, CfoI, and ScrFI. Phenetic and cladistic analyses of the data were used to infer the genetic relatedness and evolution of toxic and bloom-forming cyanobacteria. PMID:8526499

  20. Fate of cyanobacteria in drinking water treatment plant lagoon supernatant and sludge.

    PubMed

    Pestana, Carlos J; Reeve, Petra J; Sawade, Emma; Voldoire, Camille F; Newton, Kelly; Praptiwi, Radisti; Collingnon, Lea; Dreyfus, Jennifer; Hobson, Peter; Gaget, Virginie; Newcombe, Gayle

    2016-09-15

    In conventional water treatment processes, where the coagulation and flocculation steps are designed to remove particles from drinking water, cyanobacteria are also concentrated into the resultant sludge. As a consequence, cyanobacteria-laden sludge can act as a reservoir for metabolites such as taste and odour compounds and cyanotoxins. This can pose a significant risk to water quality where supernatant from the sludge treatment facility is returned to the inlet to the plant. In this study the complex processes that can take place in a sludge treatment lagoon were investigated. It was shown that cyanobacteria can proliferate in the conditions manifest in a sludge treatment lagoon, and that cyanobacteria can survive and produce metabolites for at least 10days in sludge. The major processes of metabolite release and degradation are very dependent on the physical, chemical and biological environment in the sludge treatment facility and it was not possible to accurately model the net effect. For the first time evidence is provided to suggest that there is a greater risk associated with recycling sludge supernatant than can be estimated from the raw water quality, as metabolite concentrations increased by up to 500% over several days after coagulation, attributed to increased metabolite production and/or cell proliferation in the sludge. PMID:27265732

  1. Dual KaiC-based oscillations constitute the circadian system of cyanobacteria

    PubMed Central

    Kitayama, Yohko; Nishiwaki, Taeko; Terauchi, Kazuki; Kondo, Takao

    2008-01-01

    In the cyanobacterium Synechococcus elongatus PCC 7942, the KaiA, KaiB, and KaiC proteins are essential for the generation of circadian rhythms. Both in vivo and in vitro, phosphorylation of KaiC is regulated positively by KaiA and negatively by KaiB and shows circadian rhythmicity. The autonomous circadian cycling of KaiC phosphorylation is thought to be the basic pacemaker of the circadian clock and to control genome-wide gene expression in cyanobacteria. In this study, we found that temperature-compensated circadian oscillations of gene expression persisted even when KaiC was arrested in the phosphorylated state due to kaiA overexpression. Moreover, two phosphorylation mutants showed transcriptional oscillation with a long period. In kaiA-overexpressing and phosphorylation-deficient strains, KaiC oscillated and transient overexpression of phosphorylation-deficient kaiC reset the phase of the rhythm. These results suggest that transcription- and translation-based oscillations in KaiC abundance are also important for circadian rhythm generation in cyanobacteria. Furthermore, at low temperature, cyanobacteria can show circadian rhythms only when both the KaiC phosphorylation cycle and the transcription and translation cycle are intact. Our findings indicate that multiple coupled oscillatory systems based on the biochemical properties of KaiC are important to maintain robust and precise circadian rhythms in cyanobacteria. PMID:18477603

  2. Are fish fed with cyanobacteria safe, nutritious and delicious? A laboratory study.

    PubMed

    Liang, Hualei; Zhou, Wenshan; Zhang, Yulei; Qiao, Qin; Zhang, Xuezhen

    2015-01-01

    Toxic cyanobacterial blooms, which produce cyclic heptapeptide toxins known as microcystins, are worldwide environmental problems. On the other hand, the cyanobacteria protein (30-50%) has been recommended as substitute protein for aquaculture. The present laboratory study verified the feasibility of cyanobacteria protein substitution and risk assessment. Goldfish were fed diets supplemented lyophilised cyanobacteria powder for 16 weeks with the various doses: 0% (control), 10%, 20%, 30% and 40%. Low doses (10% and 20%) promoted growth whereas high doses (30% and 40%) inhibited growth. In cyanobacteria treated fish, the proximate composition of ash, crude fat content and crude protein content decreased in 16 weeks; the saturated fatty acid (SFA) content significantly increased; the n-3 polyunsaturated fatty acid content, collagen content and muscle pH significantly decreased; cooking loss percents increased significantly. Muscle fiber diameter and myofibril length were negatively correlation. Additionally, flavour compounds (e.g., amino acids, nucleotides, organic acids and carnosine) changed significantly in the treated fish, and odour compounds geosmin and 2-methylisoborneol increased significantly. The estimated daily intake (EDI) of microcystins in muscle was close to or exceeded the World Health Organization (WHO) tolerable daily intake (TDI), representing a great health risk. Cyanobacterie is not feasible for protein sources use in aquaculture. PMID:26470644

  3. Are fish fed with cyanobacteria safe, nutritious and delicious? A laboratory study

    NASA Astrophysics Data System (ADS)

    Liang, Hualei; Zhou, Wenshan; Zhang, Yulei; Qiao, Qin; Zhang, Xuezhen

    2015-10-01

    Toxic cyanobacterial blooms, which produce cyclic heptapeptide toxins known as microcystins, are worldwide environmental problems. On the other hand, the cyanobacteria protein (30-50%) has been recommended as substitute protein for aquaculture. The present laboratory study verified the feasibility of cyanobacteria protein substitution and risk assessment. Goldfish were fed diets supplemented lyophilised cyanobacteria powder for 16 weeks with the various doses: 0% (control), 10%, 20%, 30% and 40%. Low doses (10% and 20%) promoted growth whereas high doses (30% and 40%) inhibited growth. In cyanobacteria treated fish, the proximate composition of ash, crude fat content and crude protein content decreased in 16 weeks; the saturated fatty acid (SFA) content significantly increased; the n-3 polyunsaturated fatty acid content, collagen content and muscle pH significantly decreased; cooking loss percents increased significantly. Muscle fiber diameter and myofibril length were negatively correlation. Additionally, flavour compounds (e.g., amino acids, nucleotides, organic acids and carnosine) changed significantly in the treated fish, and odour compounds geosmin and 2-methylisoborneol increased significantly. The estimated daily intake (EDI) of microcystins in muscle was close to or exceeded the World Health Organization (WHO) tolerable daily intake (TDI), representing a great health risk. Cyanobacterie is not feasible for protein sources use in aquaculture.

  4. Are fish fed with cyanobacteria safe, nutritious and delicious? A laboratory study

    PubMed Central

    Liang, Hualei; Zhou, Wenshan; Zhang, Yulei; Qiao, Qin; Zhang, Xuezhen

    2015-01-01

    Toxic cyanobacterial blooms, which produce cyclic heptapeptide toxins known as microcystins, are worldwide environmental problems. On the other hand, the cyanobacteria protein (30–50%) has been recommended as substitute protein for aquaculture. The present laboratory study verified the feasibility of cyanobacteria protein substitution and risk assessment. Goldfish were fed diets supplemented lyophilised cyanobacteria powder for 16 weeks with the various doses: 0% (control), 10%, 20%, 30% and 40%. Low doses (10% and 20%) promoted growth whereas high doses (30% and 40%) inhibited growth. In cyanobacteria treated fish, the proximate composition of ash, crude fat content and crude protein content decreased in 16 weeks; the saturated fatty acid (SFA) content significantly increased; the n-3 polyunsaturated fatty acid content, collagen content and muscle pH significantly decreased; cooking loss percents increased significantly. Muscle fiber diameter and myofibril length were negatively correlation. Additionally, flavour compounds (e.g., amino acids, nucleotides, organic acids and carnosine) changed significantly in the treated fish, and odour compounds geosmin and 2-methylisoborneol increased significantly. The estimated daily intake (EDI) of microcystins in muscle was close to or exceeded the World Health Organization (WHO) tolerable daily intake (TDI), representing a great health risk. Cyanobacterie is not feasible for protein sources use in aquaculture. PMID:26470644

  5. A STATUS REPORT ON PLANKTONIC CYANOBACTERIA (BLUE-GREEN ALGAE) AND THEIR TOXINS

    EPA Science Inventory

    Toxic blue-green algae (cyanobacteria) continue to be agents of certain waterbased toxicoses. heir presence is now being acknowledged in many of the world's fresh and brackish waters with eutrophication status of meso to hypereutrophic. ense surface scums called waterblooms will ...

  6. Glycolipid biosynthesis in cyanobacteria. [Anabaena variabilis; Chlorogloeopsis sp. ; Schizothrix calcicola; Anacystis nidulans; Anacystis marina

    SciTech Connect

    Van Dusen, W.J.; Jaworski, J.G.

    1987-05-01

    The biosynthesis of monogalactosyldiacyl-glycerol (MGDG) was studied in five different cyanobacteria. Previous work has shown Anabaena variabilis to synthesize both MGDG and monoglucosyl-diacylglycerol (MG1cDG) with MG1cDG being the precursor of MGDG. They have examined four other cyanobacteria to determine if a similar relationship exists. The cyanobacteria studied were Anabaena variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis nidulans, and Anacystis marina. Each were grown in liquid culture and lipids were labeled with /sup 14/C)CO/sub 2/ for 20 min., 1.0 hr, 1.0 hr + 10 hr chase. Glycolipids were analyzed by initial separation of MGDG and MG1cDG by TLC followed by further analysis by HPLC. Complete separation of molecular species was obtained isocratically on an ODS column. All of the cyanobacteria labeled 16-C and 18-C fatty acids except for A. marina which labeled only 14-C and 16-C fatty acids. Desaturation of the fatty acids could be observed in the 1.0 hr and chase experiments. All were capable of labeling both MG1cDG and MGDG with the precursor-product relationship being observed. There does not appear to be a direct relationship between the epimerization of the sugar moiety and fatty acid desaturation.

  7. Phylogenetic analysis of heterocystous cyanobacteria (Subsections IV and V) using highly iterated palindromes as molecular markers.

    PubMed

    Singh, Prashant; Kaushik, Manish Singh; Srivastava, Meenakshi; Mishra, Arun Kumar

    2014-07-01

    Highly iterated palindromes (HIP) have been used as high resolution molecular markers for assessing the genetic variability and phylogenetic relatedness of heterocystous cyanobacteria (subsections IV and V) representing 12 genera of heterocystous cyanobacteria, collected from different geographical areas of India. DNA fingerprints generated using four HIP markers viz. HIP-AT, HIP-CA, HIP-GC, and HIP-TG showed 100 % polymorphism in all the heterocystous cyanobacteria studied and each marker produced unique and strain-specific banding pattern. Furthermore, phylogenetic affinities based on the dendrogram constructed using HIP DNA profiles of heterocystous cyanobacteria suggest the monophyletic origin of this entire heterocystous clade along with a clear illustration of the polyphyletic origin of the branched Stigonematalean order (Subsection V). In addition, phylogenetic affinities were validated by principal component analysis of the HIP fingerprints. The overall data obtained by both the phylogeny and principal component assessments proved that the entire heterocystous clade was intermixed, and there are immediate needs for classificatory reforms that satisfy morphological plasticity and environmental concerns. PMID:25049460

  8. Removal of cyanobacteria from synthetic and real water by dielectric barrier discharge process.

    PubMed

    Zhang, Yi; Chew, Stephanie Ting Yu; Te, Shu Harn; Lim, Tuti Mariana

    2015-12-01

    The feasibility of cyanobacteria removal from freshwater by a dielectric barrier discharge (DBD) process is investigated. Seven commercial and environmental cyanobacteria strains, as well as real algae-laden water, were tested. The removal of the cyanobacteria was evaluated by analyzing the changes in chlorophyll a content, total organic carbon (TOC) concentration, and cell morphology. Nearly total removal of chlorophyll a was achieved within 20 min, while the TOC analysis exhibited an increase-decrease-increase trend in 60 min of treatment, likely due to the oxidation of intracellular and intercellular materials. Observation under light microscopy revealed the disruption of intracellular and intercellular structures within 5 min of DBD treatment and thus supported the TOC analysis. Increasing the salinity of the medium from 0 to 5 parts per thousand (ppt) improved treatment efficiency, where similar level of chlorophyll a removal (around 93%) was achieved in only half the treatment time. Application of DBD on real algae-laden water from a fish farm yielded higher treatment efficiency than in synthetic medium, indicating the promising application of DBD as a means to control cyanobacteria bloom in fresh and estuary water bodies. PMID:26213133

  9. Beating the blues: is there any music in fighting cyanobacteria with ultrasound?

    PubMed

    Lürling, Miquel; Tolman, Yora

    2014-12-01

    The hypothesis that cyanobacteria can be controlled by commercially available ultrasound transducers was tested in laboratory experiments with cultures of the cyanobacteria Anabaena sp., Cylindrospermopsis raciborskii and Microcystis aeruginosa and the green alga Scenedesmus obliquus that were grown in the absence or presence of ultrasound (mix of 20, 28 and 44 kHz). The Scenedesmus experiment also included a treatment with the zooplankton grazer Daphnia magna. Chlorophyll-a and biovolume-based growth of Anabaena was significantly lower in ultrasound exposed cultures than in controls. Particle based growth rates were higher in ultrasound treatments. Filaments were significantly shorter in ultrasound exposed cultures reflecting filament breakage. Photosystem II efficiency was not affected by ultrasound. In Cylindrospermopsis chlorophyll-a based growth rates and photosystem II efficiencies were similar in controls and ultrasound treatments, but biovolume-based growth was significantly lower in ultrasound exposed cultures compared to controls. Despite biovolume growth rates of the filamentous cyanobacteria were reduced in ultrasound treatments compared to controls, growth remained positive implying still a population increase. In Microcystis and Scenedesmus growth rates were similar in controls and ultrasound treatments. Hence, no effect of ultrasound on these phytoplankton species was found. Ultrasound should not be viewed "environmental friendly" as it killed all Daphnia within 15 min, releasing Scenedesmus from grazing control in the cultures. Based on our experiments and critical literature review, we conclude that there is no music in controlling cyanobacteria in situ with the commercially available ultrasound transducers we have tested. PMID:25240117

  10. Sensitization of a child to cyanobacteria after recreational swimming in a lake

    EPA Science Inventory

    We report a case of an 11 year-old white female who developed an allergic reaction after swimming in Lake Ontario, Canada. Specific IgE reactivity to various species of cyanobacteria extracts was found to be increased in the patient’s serum. This case emphasizes the importance of...

  11. Multidecadal time series of satellite-detected accumulations of cyanobacteria in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Kahru, M.; Elmgren, R.

    2014-07-01

    Cyanobacteria, primarily of the species Nodularia spumigena, form extensive surface accumulations in the Baltic Sea in July and August, ranging from diffuse flakes to dense surface scums. The area of these accumulations can reach ~ 200 000 km2. We describe the compilation of a 35-year-long time series (1979-2013) of cyanobacteria surface accumulations in the Baltic Sea using multiple satellite sensors. This appears to be one of the longest satellite-based time series in biological oceanography. The satellite algorithm is based on remote sensing reflectance of the water in the red band, a measure of turbidity. Validation of the satellite algorithm using horizontal transects from a ship of opportunity showed the strongest relationship with phycocyanin fluorescence (an indicator of cyanobacteria), followed by turbidity and then by chlorophyll a fluorescence. The areal fraction with cyanobacteria accumulations (FCA) and the total accumulated area affected (TA) were used to characterize the intensity and extent of the accumulations. The fraction with cyanobacteria accumulations was calculated as the ratio of the number of detected accumulations to the number of cloud-free sea-surface views per pixel during the season (July-August). The total accumulated area affected was calculated by adding the area of pixels where accumulations were detected at least once during the season. The fraction with cyanobacteria accumulations and TA were correlated (R2 = 0.55) and both showed large interannual and decadal-scale variations. The average FCA was significantly higher for the second half of the time series (13.8%, 1997-2013) than for the first half (8.6%, 1979-1996). However, that does not seem to represent a long-term trend but decadal-scale oscillations. Cyanobacteria accumulations were common in the 1970s and early 1980s (FCA between 11-17%), but rare (FCA below 4%) during 1985-1990; they increased again starting in 1991 and particularly in 1999, reaching maxima in FCA (~ 25

  12. Response of enzymes involved in the processes of antioxidation towards benthiocarb and methylparathion in cyanobacteria Nostoc muscorum

    SciTech Connect

    Bhunia, A.K.; Roy, D.; Basu, N.K.; Chakrabarti, A.; Banerjee, S.K. )

    1991-08-01

    Recently, it has been observed in the authors' laboratory that growth, nitrogen fixation, protein content of cyanobacteria Nostoc muscorum were reduced by methylparathion and benthiocarb treatment. Though many works on toxicity of pesticides on cyanobacteria, specially on growth, photosynthesis and nitrogen fixation are available, the effects of pesticides on antioxidant enzyme levels is still unclear. In this communication, studies have been presented on the effects of organophosphate insecticide methyl-parathione and carbamate herbicide benthiocarb, on glutathione content, glutathione reductase (GR) and superoxide dismutase (SOD) activities of filamentous, nitrogen-fixing cyanobacteria Nostoc muscorum.

  13. Evidence of Substrate Specialization among Euendolithic Cyanobacteria from Mona Island, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Couradeau, E.; Roush, D.; Guida, B. S.; Garcia-Pichel, F.

    2015-12-01

    Euendolithic Cyanobacteria are able to actively bore into mineral carbonates. They are of global significance because they colonize any exposed marine, freshwater or terrestrial carbonate surface. They are responsible of shaping coastal limestomes, damaging mollusk shells, coral skeletons and historical landmarks. Despite their global importance, little is known about the boring mechanism, more specifically how Cyanobacteria realize the tour de force of combining oxygenic photosynthesis to carbonate dissolution. In fact there is only one cultured boring strain, which only bores into calcium carbonate while microborers are found on various types of substrates including magnesium carbonates. The boring mechanism proposed for the model strain may not be general highlighting the need of going back to the field to interrogate eudolithic Cyanobacterial communities boring on other substrates. We collected samples from marine intertidal limestones (mostly calcite CaCO3) and dolostones (mostly dolomite CaMg(CO3)2) from the Mona Island, Puerto Rico that were all infested by endolithic microbial communities. After determination of the samples mineralogy using powder X-ray diffraction, we analyzed the endolithic microbial communities using 16S rDNA library next generation sequencing. Our results indicate that the substrate type does not drive any significant difference in community composition at the phylum level but affects the distribution of Cyanobacteria. We found that while close relatives to the model strain Mastigocoleus testarum BC008 are prominent in limestones, 2 OTUs accounting for up to 26% of the Cyanobacteria, they are in low abundance in dolostones. These latter being dominated by members of the Pleurocapsales closely related to the known boring strain Hyella sp. This study brings the first evidence of substrate specialization among euendolithic Cyanobacteria and stresses the need of studying dolostone boring strains in more details.

  14. [Characterization of Black and Dichothrix Cyanobacteria Based on the 16S Ribosomal RNA Gene Sequence

    NASA Technical Reports Server (NTRS)

    Ortega, Maya

    2010-01-01

    My project focuses on characterizing different cyanobacteria in thrombolitic mats found on the island of Highborn Cay, Bahamas. Thrombolites are interesting ecosystems because of the ability of bacteria in these mats to remove carbon dioxide from the atmosphere and mineralize it as calcium carbonate. In the future they may be used as models to develop carbon sequestration technologies, which could be used as part of regenerative life systems in space. These thrombolitic communities are also significant because of their similarities to early communities of life on Earth. I targeted two cyanobacteria in my research, Dichothrix spp. and whatever black is, since they are believed to be important to carbon sequestration in these thrombolitic mats. The goal of my summer research project was to molecularly identify these two cyanobacteria. DNA was isolated from each organism through mat dissections and DNA extractions. I ran Polymerase Chain Reactions (PCR) to amplify the 16S ribosomal RNA (rRNA) gene in each cyanobacteria. This specific gene is found in almost all bacteria and is highly conserved, meaning any changes in the sequence are most likely due to evolution. As a result, the 16S rRNA gene can be used for bacterial identification of different species based on the sequence of their 16S rRNA gene. Since the exact sequence of the Dichothrix gene was unknown, I designed different primers that flanked the gene based on the known sequences from other taxonomically similar cyanobacteria. Once the 16S rRNA gene was amplified, I cloned the gene into specialized Escherichia coli cells and sent the gene products for sequencing. Once the sequence is obtained, it will be added to a genetic database for future reference to and classification of other Dichothrix sp.

  15. The evolution of Carbon isotopes in calcite in the presence of cyanobacteria

    NASA Astrophysics Data System (ADS)

    Grimm, Christian; Mavromatis, Vasileios; Pokrovsky, Oleg S.; Oelkers, Eric H.

    2016-04-01

    Stable isotopic compositions in carbonates are widely used as indicators of environmental conditions prevailing during mineral formation. This reconstruction is substantially based on the assumption that there is no change in the mineral composition over geological time. However, recent experimental studies have shown that carbon and magnesium isotopes in hydrous Mg-carbonates undergo continuous re-equilibration with the ambient solution even after mineral precipitation stopped ([1] and [2], respectively). To verify whether this holds true for anhydrous Ca-bearing carbonates which readily form at earth's surface environments, a series of batch system calcite precipitation experiments were performed in the presence of actively growing cyanobacteria Synechococcus sp. The bacteria were grown at ambient temperature in a BG11 culture medium (SIGMA C3061) and continuous stirring, air-bubbling and illumination. Calcite precipitation was initiated by the addition of 8.5mM CaCl2 and 0-50 mM NaHCO3 or NaHCO3-Na2CO3 mixtures. The presence of cyanobacteria is on one hand promoting CaCO3 formation due to increasing pH resulting from photosynthesis. On the other hand, actively growing cyanobacteria drastically change carbon isotope signature of the aqueous fluid phase by preferably incorporating the lighter 12C isotope into biomass [1]. This study explores the effect of continuously changing carbon isotope compositions in dissolved inorganic carbon (DIC) on precipitated calcite which is in chemical equilibrium with the ambient fluid phase. [1] Mavromatis et al. (2015). The continuous re-equilibration of carbon isotope compositions of hydrous Mg-carbonates in the presence of cyanobacteria. Chem. Geol. 404, 41-51 [2] Mavromatis et al. (2012). Magnesium isotope fractionation during hydrous magnesium carbonate precipitation with and without cyanobacteria. Geochim. Cosmochim. Acta 76, 161-174

  16. Low-wind summers promote blooms of cyanobacteria in Lake Tiefer See, NE Germany

    NASA Astrophysics Data System (ADS)

    Kienel, Ulrike; Kirillin, Georgiy; Brademann, Brian; Plessen, Brigit; Dräger, Nadine; Brauer, Achim

    2016-04-01

    Low-wind summers promote blooms of cyanobacteria in Lake Tiefer See, NE Germany Monitoring in three successive but meteorologically different summer seasons in 2012 to 2014 revealed a major impact of the duration of low-wind periods in summer on the outcome of cyanobacteria blooms. During summer 2014, the period from mid-June to mid-September with wind speeds below the average of 3.5 m s-1 promoted a bloom of Limnothrix redekekei with up to 12 mg particulate matter per liter. This bloom from June to September 2014 led to an enrichment of 13C in the organic matter deposited, and terminated a weak diatom spring bloom. The shorter low-wind period from mid-July to mid-September 2012 caused a less strong 13C enrichment by a weak bloom of cyanobacteria, which coexisted with diatoms, while no such bloom occurred during generally windier summer 2013. The validity of the observed relation of 13C enrichment by cyanobacteria blooms during extended low-wind periods in summer was tested using annual measurements of delta13Corg in the varved sediments deposited between AD1924 and 2008 and the mixing depth as derived from FLake-model calculations based on meteorological data from Schwerin (for 1951-2008). Accordingly, the duration of mixing depth less than 3.5 m water depth explains 25% of the variability of 13C enrichment by cyanobacteria blooms for the full period from 1951 - 2006. The explained variability increases to 53% when the period with increased nutrient load from1970 onwards is considered. In terms of explained variability of lake production, this relation is supplementary to the inverse relation of diatom silica determined by the duration of lake mixing in spring, which is suppressed during the period of increased nutrient load.

  17. Planktic Tychonema (Cyanobacteria) in the large lakes south of the Alps: phylogenetic assessment and toxigenic potential.

    PubMed

    Salmaso, Nico; Cerasino, Leonardo; Boscaini, Adriano; Capelli, Camilla

    2016-10-01

    This work allowed assessing a widespread occurrence of Tychonema bourrellyi in the largest lakes south of the Alps (Garda, Iseo, Como and Maggiore). The taxonomy of the species was confirmed adopting a polyphasic approach, which included microscopic examinations, molecular (16S rRNA and rbcLX sequences) and (Lake Garda) ecological characterisations. Over 70% of the 36 isolates of Tychonema sampled from the four lakes tested positive for the presence of genes implicated in the biosynthesis of anatoxins (anaF and/or anaC) and for the production of anatoxin-a (ATX) and homoanatoxin-a (HTX). A detailed analysis carried out in Lake Garda showed strong ongoing changes in the cyanobacterial community, with populations of Tychonema developing with higher biovolumes compared to the microcystins (MCs) producer Planktothrix rubescens Moreover, the time × depth distribution of Tychonema was paralleled by a comparable distribution of ATX and HTX. The increasing importance of Tychonema in Lake Garda was also suggested by the opposite trends of ATX and MCs observed since 2009. These results suggest that radical changes are occurring in the largest lakes south of the Alps. Their verification and implications will require to be assessed by extending a complete experimental work to the other large perialpine lakes. PMID:27402712

  18. First Report of a Toxic Nodularia spumigena (Nostocales/ Cyanobacteria) Bloom in Sub-Tropical Australia. I. Phycological and Public Health Investigations

    PubMed Central

    McGregor, Glenn B.; Stewart, Ian; Sendall, Barbara C.; Sadler, Ross; Reardon, Karen; Carter, Steven; Wruck, Dan; Wickramasinghe, Wasa

    2012-01-01

    Cyanobacterial blooms represent one of the most conspicuous and widespread waterborne microbial hazards to human and ecosystem health. Investigation of a cyanobacterial bloom in a shallow brackish water recreational cable ski lake in south-eastern Queensland, Australia revealed the dominance of the toxigenic species Nodularia spumigena. The bloom spanned three months, during which time cell concentrations exceeded human guideline thresholds for recreational risk, and concentrations of the hepatotoxic cyanotoxin nodularin exceeded 200 µg L−1. Cyanotoxin origin and identification was confirmed by amplification of the ndaF-specific PCR product and sequencing of the 16S rRNA gene. From the limited data available leading up to, and throughout the bloom, it was not possible to establish the set of causative factors responsible for its occurrence. However a combination of factors including salinity, hydraulic retention time and nutrient status associated with an extended period of drought are likely to have contributed. This was the first known occurrence of this species in bloom proportions from sub-tropical Australia and as such represents a hitherto uncharacterized risk to human and ecosystem health. It highlights the need for adaptive monitoring regimes to ensure a comprehensive understanding of the potentially toxic cyanobacteria likely to inhabit any given region. Such monitoring needs to recognize that cyanobacteria have a significant capacity for range expansion that has been facilitated by recent changes in global climate. PMID:22851951

  19. A combined morphological, ultrastructural, molecular, and biochemical study of the peculiar family Gomontiellaceae (Oscillatoriales) reveals a new cylindrospermopsin-producing clade of cyanobacteria.

    PubMed

    Bohunická, Markéta; Mareš, Jan; Hrouzek, Pavel; Urajová, Petra; Lukeš, Martin; Šmarda, Jan; Komárek, Jiří; Gaysina, Lira A; Strunecký, Otakar

    2015-12-01

    Members of the morphologically unusual cyanobacterial family Gomontiellaceae were studied using a polyphasic approach. Cultured strains of Hormoscilla pringsheimii, Starria zimbabweënsis, Crinalium magnum, and Crinalium epipsammum were thoroughly examined, and the type specimen of the family, Gomontiella subtubulosa, was investigated. The results of morphological observations using both light microscopy and transmission electron microscopy were consistent with previous reports and provided evidence for the unique morphological and ultrastructural traits of this family. Analysis of the 16S rRNA gene confirmed the monophyletic origin of non-marine repre-sentatives of genera traditionally classified into this family. The family was phylogenetically placed among other groups of filamentous cyanobacterial taxa. The presence of cellulose in the cell wall was analyzed and confirmed in all cultured Gomontiellaceae members using Fourier transform infrared spectroscopy and fluorescence microscopy. Evaluation of toxins produced by the studied strains revealed the hepatotoxin cylindrospermopsin (CYN) in available strains of the genus Hormoscilla. Production of this compound in both Hormoscilla strains was detected using high-performance liquid chromatography in tandem with high resolution mass spectrometry and confirmed by positive PCR amplification of the cyrJ gene from the CYN biosynthetic cluster. To our knowledge, this is the first report of CYN production by soil cyanobacteria, establishing a previously unreported CYN-producing lineage. This study indicates that cyanobacteria of the family Gomontiellaceae form a separate but coherent cluster defined by numerous intriguing morphological, ultrastructural, and biochemical features, and exhibiting a toxic potential worthy of further investigation. PMID:26987000

  20. Evolutionary relationships among eubacteria, cyanobacteria, and chloroplasts: evidence from the rpoC1 gene of Anabaena sp. strain PCC 7120.

    PubMed Central

    Bergsland, K J; Haselkorn, R

    1991-01-01

    RNA polymerases of cyanobacteria contain a novel core subunit, gamma, which is absent from the RNA polymerases of other eubacteria. The genes encoding the three largest subunits of RNA polymerase, including gamma, have been isolated from the cyanobacterium Anabaena sp. strain PCC 7120. The genes are linked in the order rpoB, rpoC1, rpoC2 and encode the beta, gamma, and beta' subunits, respectively. These genes are analogous to the rpoBC operon of Escherichia coli, but the functions of rpoC have been split in Anabaena between two genes, rpoC1 and rpoC2. The DNA sequence of the rpoC1 gene was determined and shows that the gamma subunit corresponds to the amino-terminal half of the E. coli beta' subunit. The gamma protein contains several conserved domains found in the largest subunits of all bacterial and eukaryotic RNA polymerases, including a potential zinc finger motif. The spliced rpoC1 gene from spinach chloroplast DNA was expressed in E. coli and shown to encode a protein immunologically related to Anabaena gamma. The similarities in the RNA polymerase gene products and gene organizations between cyanobacteria and chloroplasts support the cyanobacterial origin of chloroplasts and a divergent evolutionary pathway among eubacteria. Images PMID:1904436

  1. First report of a toxic Nodularia spumigena (Nostocales/ Cyanobacteria) bloom in sub-tropical Australia. I. Phycological and public health investigations.

    PubMed

    McGregor, Glenn B; Stewart, Ian; Sendall, Barbara C; Sadler, Ross; Reardon, Karen; Carter, Steven; Wruck, Dan; Wickramasinghe, Wasa

    2012-07-01

    Cyanobacterial blooms represent one of the most conspicuous and widespread waterborne microbial hazards to human and ecosystem health. Investigation of a cyanobacterial bloom in a shallow brackish water recreational cable ski lake in south-eastern Queensland, Australia revealed the dominance of the toxigenic species Nodularia spumigena. The bloom spanned three months, during which time cell concentrations exceeded human guideline thresholds for recreational risk, and concentrations of the hepatotoxic cyanotoxin nodularin exceeded 200 µg L(-1). Cyanotoxin origin and identification was confirmed by amplification of the ndaF-specific PCR product and sequencing of the 16S rRNA gene. From the limited data available leading up to, and throughout the bloom, it was not possible to establish the set of causative factors responsible for its occurrence. However a combination of factors including salinity, hydraulic retention time and nutrient status associated with an extended period of drought are likely to have contributed. This was the first known occurrence of this species in bloom proportions from sub-tropical Australia and as such represents a hitherto uncharacterized risk to human and ecosystem health. It highlights the need for adaptive monitoring regimes to ensure a comprehensive understanding of the potentially toxic cyanobacteria likely to inhabit any given region. Such monitoring needs to recognize that cyanobacteria have a significant capacity for range expansion that has been facilitated by recent changes in global climate. PMID:22851951

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

    EPA Science Inventory

    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 associat...

  3. Cyanobacterial Toxins as Allelochemicals with Potential Applications as Algaecides, Herbicides and Insecticides

    PubMed Central

    Berry, John P.; Gantar, Miroslav; Perez, Mario H.; Berry, Gerald; Noriega, Fernando G.

    2008-01-01

    Cyanobacteria (“blue-green algae”) from marine and freshwater habitats are known to produce a diverse array of toxic or otherwise bioactive metabolites. However, the functional role of the vast majority of these compounds, particularly in terms of the physiology and ecology of the cyanobacteria that produce them, remains largely unknown. A limited number of studies have suggested that some of the compounds may have ecological roles as allelochemicals, specifically including compounds that may inhibit competing sympatric macrophytes, algae and microbes. These allelochemicals may also play a role in defense against potential predators and grazers, particularly aquatic invertebrates and their larvae. This review will discuss the existing evidence for the allelochemical roles of cyanobacterial toxins, as well as the potential for development and application of these compounds as algaecides, herbicides and insecticides, and specifically present relevant results from investigations into toxins of cyanobacteria from the Florida Everglades and associated waterways. PMID:18728763

  4. Effect of mineral phosphates on growth and nitrogen fixation of diazotrophic cyanobacteria Anabaena variabilis and Westiellopsis prolifica.

    PubMed

    Yandigeri, Mahesh S; Yadav, Arvind K; Meena, Kamlesh Kumar; Pabbi, Sunil

    2010-03-01

    The nitrogen fixing cyanobacterial strains namely Anabaena variabilis (Nostocales, Nostocaceae) and Westiellopsis prolifica (Nostocales, Hapalosiphonaceae) were evaluated for their nitrogen fixation and growth potential in response to different concentrations (10, 20 and 30 mg P) of the alternate insoluble P-sources Mussorie Rock Phosphate and Tricalcium Phosphate. Distinct and significant intergeneric differences were observed with respect to nitrogen fixation measured as Acetylene Reduction Activity (ARA) and growth potential as soluble proteins, total carbohydrate content, dry weight and total chlorophyll content in response to different concentrations of Mussorie Rock Phosphate and Tricalcium Phosphate. Both the strains showed higher soluble protein content at 20 mg P (Mussorie Rock Phosphate) that increased with time of incubation in A. variabilis. Both cyanobacteria recorded maximum Acetylene Reduction Activity at 20 mg P (Tricalcium Phosphate) followed by activity in presence of soluble phosphate (K2HPO4). The mean activity at all concentrations of insoluble phosphate (Mussorie Rock Phosphate and Tricalcium Phosphate) was more than in the presence of soluble phosphate. PMID:20069361

  5. Iron, Sulfur, Arsenic and Water: Geochemical Implications of Facultative Anoxygenic Photosynthesis in Cyanobacteria and the Slow Rise of Oxygen

    NASA Astrophysics Data System (ADS)

    Wolfe-Simon, F.; Johnston, D. T.; Girguis, P. R.; Pearson, A.; Knoll, A. H.

    2008-12-01

    Over geologic time, the global rise in atmospheric oxygen (O2) is attributed to the evolution and wide spread proliferation of oxygenic photosynthesis in cyanobacteria. However, cyanobacteria maintain a metabolic flexibility that may not always result in O2 release. Specifically, cyanobacteria can use a variety of alternative electron donors, rather than water, that are also readily oxidized. These may include sulfur, iron, and arsenic. Cyanobacteria are thus not uniquely constrained towards O2 production. Changes in the bioavailability of these key elements may have had dramatic consequences for and resulted in the slow accumulation of O2 in the atmosphere. In particular, by using facultative anoxygenic photosynthesis the cells maintain advantageous anaerobic conditions for N2-fixation. Although other types of bacteria are capable of N2-fixation, cyanobacteria singularly possess the dynamic capability of generating and surviving O2. These two processes "pull" the cells in opposite directions, metabolically speaking, around an aerobic-anaerobic continuum. Such a strategy also confers a distinct competitive advantage for cyanobacteria over photosynthetic eukaryotes, as they can endure widespread euxinia and maintain their cellular N quota. In an anoxic and/or sulfidic ocean, cyanobacteria would be expected to dominate over eukaryotic algae. Here we present Bayesian constructed phylogenetic distribution of specific genes and the metabolic role of key enzymes that form the basis of this hypothesis. We further suggest that the consequences of this proposed ecosystem structure altered the redox balance of the fluid Earth (atmosphere and oceans) and can help explain the observed long-term geochemical stasis and slow rates of eukaryotic diversification. We suggest that the underlying control for global oxygenation was a synergistic interplay between the evolution and elastic physiology of cyanobacteria as they impacted the redox state of early Earth.

  6. Fate and transport of cyanobacteria and associated toxins and taste-and-odor compounds from upstream reservoir releases in the Kansas River, Kansas, September and October 2011

    USGS Publications Warehouse

    Graham, Jennifer L.; Ziegler, Andrew C.; Loving, Brian L.; Loftin, Keith A.

    2012-01-01

    Cyanobacteria cause a multitude of water-quality concerns, including the potential to produce toxins and taste-and-odor compounds. Toxins and taste-and-odor compounds may cause substantial economic and public health concerns and are of particular interest in lakes, reservoirs, and rivers that are used for drinking-water supply, recreation, or aquaculture. The Kansas River is a primary source of drinking water for about 800,000 people in northeastern Kansas. Water released from Milford Lake to the Kansas River during a toxic cyanobacterial bloom in late August 2011 prompted concerns about cyanobacteria and associated toxins and taste-and-odor compounds in downstream drinking-water supplies. During September and October 2011 water-quality samples were collected to characterize the transport of cyanobacteria and associated compounds from upstream reservoirs to the Kansas River. This study is one of the first to quantitatively document the transport of cyanobacteria and associated compounds during reservoir releases and improves understanding of the fate and transport of cyanotoxins and taste-and-odor compounds downstream from reservoirs. Milford Lake was the only reservoir in the study area with an ongoing cyanobacterial bloom during reservoir releases. Concentrations of cyanobacteria and associated toxins and taste-and-odor compounds in Milford Lake (upstream from the dam) were not necessarily indicative of outflow conditions (below the dam). Total microcystin concentrations, one of the most commonly occurring cyanobacterial toxins, in Milford Lake were 650 to 7,500 times higher than the Kansas Department of Health and Environment guidance level for a public health warning (20 micrograms per liter) for most of September 2011. By comparison, total microcystin concentrations in the Milford Lake outflow generally were less than 10 percent of the concentrations in surface accumulations, and never exceeded 20 micrograms per liter. The Republican River, downstream from

  7. Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites: Implications to Life on Comets, Europa and Enceladus

    NASA Astrophysics Data System (ADS)

    Hoover, Richard B.

    2011-10-01

    Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) investigations of the internal surfaces of the CI1 Carbonaceous Meteorites have yielded images of large complex filaments. The filaments have been observed to be embedded in freshly fractured internal surfaces of the stones. They exhibit recognizable features (e.g., the size and size ranges of the internal cells and their location and arrangement within sheaths) that are diagnostic of known genera and species of filamentous trichomic cyanobacteria and other trichomic prokaryotes (such as filamentous sulfur bacteria). ESEM and FESEM studies of living and fossil cyanobacteria show features similar to the filaments found in the meteorites -- uniseriate and multiseriate, branched or unbranched, isodiametric or tapered, polarized or unpolarized filaments with trichomes encased within thin or thick external sheaths. Some of the filaments found in the CI1 meteorites also exhibit specialized cells and structures used by cyanobacteria for reproduction (baeocytes, akinetes and hormogonia), nitrogen fixation (basal, intercalary or apical heterocysts), attachment (pili or fimbriae) or indicative of oscillatoria type locomotion (escaped or coiling hormogonia and flattened and coiled empty sheaths). Energy dispersive X-ray Spectroscopy (EDS) studies indicate that the Orgueil meteorite filaments are typically carbon-rich sheaths infilled with magnesium sulfate and other minerals characteristic of the CI1 carbonaceous meteorites. However, the size, structure, detailed morphological characteristics and chemical compositions of the meteorite filaments are not consistent with known species of abiotic minerals. The nitrogen content of the meteorite filaments are almost always below the detection limit of the EDS detector. EDS analysis of living and dead biological materials (e.g., filamentous cyanobacteria; bacteria, mummy and mammoth hair and tissues, and fossils of cyanobacteria, trilobites and insects in

  8. Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites: Implications to Life on Comets, Europa, and Enceladus

    NASA Astrophysics Data System (ADS)

    Hoover, Richard B.

    Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) investigations of the internal surfaces of the CI1 Carbonaceous Meteorites have yielded images of large complex filaments. The filaments have been observed to be embedded in freshly fractured internal surfaces of the stones. They exhibit features (e.g., the size and size ranges of the internal cells and their location and arrangement within sheaths) that are diagnostic of known genera and species of trichomic cyanobacteria and other trichomic prokaryotes such as the filamentous sulfur bacteria. ESEM and FESEM studies of living and fossil cyanobacteria show similar features in uniseriate and multiseriate, branched or unbranched, isodiametric or tapered, polarized or unpolarized filaments with trichomes encased within thin or thick external sheaths. Filaments found in the CI1 meteorites have also been detected that exhibit structures consistent with the specialized cells and structures used by cyanobacteria for reproduction (baeocytes, akinetes and hormogonia), nitrogen fixation (basal, intercalary or apical heterocysts) and attachment or motility (fimbriae). Energy dispersive X-ray Spectroscopy (EDS) studies indicate that the meteorite filaments are typically carbon rich sheaths infilled with magnesium sulfate and other minerals characteristic of the CI1 carbonaceous meteorites. The size, structure, detailed morphological characteristics and chemical compositions of the meteorite filaments are not consistent with known species of minerals. The nitrogen content of the meteorite filaments are almost always below the detection limit of the EDS detector. EDS analysis of terrestrial minerals and biological materials (e.g., fibrous epsomite, filamentous cyanobacteria; mummy and mammoth hair/tissues, and fossils of cyanobacteria, trilobites, insects in amber) indicate that nitrogen remains detectable in biological materials for thousands of years but is undetectable in the ancient fossils. These

  9. Long-term changes in cyanobacteria populations in lake kinneret (sea of galilee), Israel: an eco-physiological outlook.

    PubMed

    Hadas, Ora; Kaplan, Aaron; Sukenik, Assaf

    2015-01-01

    The long-term record of cyanobacteria abundance in Lake Kinneret (Sea of Galilee), Israel, demonstrates changes in cyanobacteria abundance and composition in the last five decades. New invasive species of the order Nostocales (Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii) became part of the annual phytoplankton assemblage during summer-autumn. Concomitantly, bloom events of Microcystis sp. (Chroococcales) during winter-spring intensified. These changes in cyanobacteria pattern may be partly attributed to the management policy in Lake Kinneret's vicinity and watershed aimed to reduce effluent discharge to the lake and partly to climate changes in the region; i.e., increased water column temperature, less wind and reduced precipitation. The gradual decrease in the concentration of total and dissolved phosphorus and total and dissolved nitrogen and an increase in alkalinity, pH and salinity, combined with the physiological features of cyanobacteria, probably contributed to the success of cyanobacteria. The data presented here indicate that the trend of the continuous decline of nutrients may not be sufficient to reduce and to control the abundance and proliferation of toxic and non-toxic cyanobacteria. PMID:25664964

  10. Tracing the isotopic signal of a cyanobacteria bloom through the food web of a Baltic Sea coastal lagoon

    NASA Astrophysics Data System (ADS)

    Lesutienė, Jūratė; Bukaveckas, Paul A.; Gasiūnaitė, Zita R.; Pilkaitytė, Renata; Razinkovas-Baziukas, Artūras

    2014-02-01

    This study shows that cyanobacteria blooms support secondary production in a diverse group of benthic and pelagic consumers and illustrate the utility of stable isotopes for tracking the cyanobacteria signal in aquatic food webs. We characterized seasonal patterns in δ13C and δ15N signatures of particulate organic matter (POM) and consumers in a eutrophic coastal lagoon (Curonian Lagoon, SE Baltic Sea) before, during and after a cyanobacteria bloom. We found that during the pre- and post-bloom periods (spring and autumn), POM from the lagoon was isotopically indistinguishable from riverine POM. During the bloom, the increase in phytoplankton biomass and dominance by N2-fixing cyanobacteria resulted in higher δ13C and lower δ15N of POM. These changes in POM were reflected in isotopic signatures of primary consumers with greatest response among fast-growing planktonic and nectobenthic crustaceans and chironomids. Results from end-member mixing analyses suggest that cyanobacteria accounted for 50-80% of production by these consumers during the bloom period. Weaker responses were observed among slow-growing species, particularly long-lived bivalves such as Dreissena. Cyanobacteria-induced shifts in δ13C and δ15N could be tracked to secondary consumers, particularly fast-growing forms such as predatory zooplankton (Leptodora) and juvenile fishes (European perch). We suggest that reconstruction of the food web at the upper trophic levels should incorporate isotopic baselines of both fast- and slow-growing primary consumers to reflect the contribution of blooms events.

  11. Long-Term Changes in Cyanobacteria Populations in Lake Kinneret (Sea of Galilee), Israel: An Eco-Physiological Outlook

    PubMed Central

    Hadas, Ora; Kaplan, Aaron; Sukenik, Assaf

    2015-01-01

    The long-term record of cyanobacteria abundance in Lake Kinneret (Sea of Galilee), Israel, demonstrates changes in cyanobacteria abundance and composition in the last five decades. New invasive species of the order Nostocales (Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii) became part of the annual phytoplankton assemblage during summer-autumn. Concomitantly, bloom events of Microcystis sp. (Chroococcales) during winter-spring intensified. These changes in cyanobacteria pattern may be partly attributed to the management policy in Lake Kinneret’s vicinity and watershed aimed to reduce effluent discharge to the lake and partly to climate changes in the region; i.e., increased water column temperature, less wind and reduced precipitation. The gradual decrease in the concentration of total and dissolved phosphorus and total and dissolved nitrogen and an increase in alkalinity, pH and salinity, combined with the physiological features of cyanobacteria, probably contributed to the success of cyanobacteria. The data presented here indicate that the trend of the continuous decline of nutrients may not be sufficient to reduce and to control the abundance and proliferation of toxic and non-toxic cyanobacteria. PMID:25664964

  12. Cyanobacteria are confined to dewless habitats within a dew desert: Implications for past and future climate change for lithic microorganisms

    NASA Astrophysics Data System (ADS)

    Kidron, Giora J.; Starinsky, Abraham; Yaalon, Dan H.

    2014-11-01

    Although covering almost all rock outcrops around the world, little is known regarding the factors that govern the spatial distribution of lithic cyanobacteria and lichens. This is also the case in the Negev Desert, where cyanobacteria predominate on the rock outcrops of the south-facing slopes and lichens on the rock outcrops of the north-facing slopes. Hypothesizing that abiotic conditions determine their distribution, radiation, temperature, rain, dew and fog were monitored over a two-year period (2008-2010) at cyanobacteria- and lichen-dwelling habitats within a first-order drainage basin in the Negev Highlands. While non-significant differences characterized the rain amounts, substantial differences in substrate temperatures were recorded which resulted in turn in fundamental differences in the non-rainfall water regime. While dew condensed at the rock outcrops of the lichen habitat, no condensation took place at the cyanobacteria habitat. Contrary to the common belief, cyanobacteria were found to inhabit dewless habitats. As a result, cyanobacteria solely rely on rain precipitation for growth and can therefore serve as bioindicators for dewless habitats within the dewy Negev Desert. The findings may have important implications regarding Earth colonization, soil forming processes and geochemical processes following climate warming. They may explain lichen expansion and subsequent O2 increase during the mid Neoproterozoic providing indirect support for substantial photosynthetic activity and high weathering rates during this era.

  13. Microcystins (cyanobacterial toxins) in surface waters of rural Bangladesh: pilot study.

    PubMed

    Welker, Martin; Khan, Saleha; Haque, Md Mahfuzul; Islam, Sirajul; Khan, Nurul Huda; Chorus, Ingrid; Fastner, Jutta

    2005-12-01

    In Bangladesh the exposure of millions of inhabitants to water from (shallow) tube wells contaminated with high geogenic loads of arsenic is a major concern. As an alternative to the costly drilling of deep wells, the return to the use of surface water as a source of drinking water is considered. In addition to the well-known hazards of water borne infectious diseases associated with the use of surface water, recently the potential public health implications of toxic cyanobacteria have been recognized. As a first step towards a risk assessment for cyanotoxins in Bangladesh surface waters, seston samples of 79 ponds were analysed in late summer 2002 for the presence of cyanobacteria and microcystins (MCYST), the most frequently detected cyanobacterial toxins worldwide. Microcystins could be detected in 39 ponds, mostly together with varying abundance of potentially microcystin-producing genera such as Microcystis, Planktothrix and Anabaena. Total microcystin concentrations ranged between <0.1 and > 1,000 microg l(-1), and more than half of the positive samples contained high concentrations of more than 10 microg l(-1). The results clearly show that concentrations of microcystins well above the provisional WHO guideline value of 1 microg l(-1) MCYST-LR can be frequently detected in Bangladesh ponds. Thus, an increasing use of surface water for human consumption introduces a risk of replacing one health hazard by another and therefore needs to be accompanied by cyanotoxin hazard assessments. PMID:16459839

  14. Biphasic Kinetic Behavior of Nitrate Reductase from Heterocystous, Nitrogen-Fixing Cyanobacteria 1

    PubMed Central

    Martin-Nieto, José; Flores, Enrique; Herrero, Antonia

    1992-01-01

    Nitrate reductase activity from filamentous, heterocyst-forming cyanobacteria showed a biphasic kinetic behavior with respect to nitrate as the variable substrate. Two kinetic components were detected, the first showing a higher affinity for nitrate (Km, 0.05-0.25 mm) and a lower catalytic activity and the second showing a lower affinity for nitrate (Km, 5-25 mm) and a higher (3- to 5-fold) catalytic activity. In contrast, among unicellular cyanobacteria, most representatives studied exhibited a monophasic, Michaelis-Menten kinetic pattern for nitrate reductase activity. Biphasic kinetics remained unchanged with the use of different assay conditions (i.e. cell disruption or permeabilization, two different electron donors) or throughout partial purification of the enzyme. PMID:16652939

  15. Recruitment of cyanobacteria from the sediments in the eutrophic Shanzi Reservoir.

    PubMed

    Su, Yuping; You, Xuejing; Lin, Hui; Zhuang, Huiru; Weng, Yuan; Zhang, Dayi

    2016-03-01

    This study investigated the impact of four environmental factors on the recruitment of cyanobacteria from bottom sediments in the eutrophic Shanzi Reservoir. Temperature and light were identified as the key determinants for the recruitment of Microcystis and Oscillatoria. Cyanobacteria became dominant at higher temperature (20°C) and light intensity (2000 lx) and Microcystis and Oscillatoria were the major species. Detailed recruitment simulation undertaken with the respective gradients of temperature and light suggested that both Microcystis and Oscillatoria are temperature sensitive and that their critical temperature point was 10°C. However, distinct light impacts were observed only on Microcystis. The recruitment of Oscillatoria was light independent, whereas Microcystis had a positive relationship with light intensity. Physical disturbance promoted Microcystis recruitment and also affected the structure of the recruited cyanobacterial community at the water-sediment interface, based on quantitative polymerase chain reaction (qPCR) and phylogenetic analysis. PMID:26215422

  16. System and method for research-scale outdoor production of microalgae and cyanobacteria.

    PubMed

    Schoepp, Nathan G; Stewart, Ryan L; Sun, Vincent; Quigley, Alexandra J; Mendola, Dominick; Mayfield, Stephen P; Burkart, Michael D

    2014-08-01

    Eukaryotic microalgae and cyanobacteria have recently reemerged as promising organisms in the effort to develop sustainable options for production of food and fuel. However, substantial discrepancies consistently arise between laboratory and outdoor cultivation, and gains demonstrated using laboratory technologies have not paralleled gains observed in field demonstrations. For these reasons, a low-maintenance system and process for research-scale outdoor cultivation of a variety of both freshwater and marine microalgae and cyanobacteria was developed. Nine genera were evaluated in the system, demonstrating cultivation of both laboratory model and commercial-production organisms. Hundreds to thousands of grams of dry biomass could be produced in a single growth cycle, suitable for a variety of uses including inoculum generation, protein production, and biofuel applications. Following testing in outdoor stock-ponds, Scenedesmus and Nannochloropsis were grown semi-continuously in an 8000 L airlift-driven raceway, yielding in total over 8 kg of dry biomass for each strain. PMID:24926599

  17. Diverse roles of the GlcP glucose permease in free-living and symbiotic cyanobacteria.

    PubMed

    Picossi, Silvia; Flores, Enrique; Ekman, Martin

    2013-01-01

    Certain cyanobacteria can form symbiotic associations with plants, where the symbiont supplies the plant partner with nitrogen and in return obtains sugars. We recently showed that in the symbiotic cyanobacterium Nostoc punctiforme, a glucose specific permease, GlcP, is necessary for the symbiosis to be formed. Results presented here from growth yield measurements of mutant strains with inactivated or overexpressing sugar transporters suggest that GlcP could be induced by a symbiosis specific substance. We also discuss that the transporter may have a role other than nutritional once the symbiosis is established, i.e., during infection, and more specifically in the chemotaxis of the symbiont. Phylogenetic analysis shows that the distribution of GlcP among cyanobacteria is likely influenced by horizontal gene transfer, but also that it is not correlated with symbiotic competence. Instead, regulatory patterns of the transporter in Nostoc punctiforme likely constitute symbiosis specific adaptations. PMID:24675169

  18. Diverse roles of the GlcP glucose permease in free-living and symbiotic cyanobacteria

    PubMed Central

    Picossi, Silvia; Flores, Enrique; Ekman, Martin

    2013-01-01

    Certain cyanobacteria can form symbiotic associations with plants, where the symbiont supplies the plant partner with nitrogen and in return obtains sugars. We recently showed that in the symbiotic cyanobacterium Nostoc punctiforme, a glucose specific permease, GlcP, is necessary for the symbiosis to be formed. Results presented here from growth yield measurements of mutant strains with inactivated or overexpressing sugar transporters suggest that GlcP could be induced by a symbiosis specific substance. We also discuss that the transporter may have a role other than nutritional once the symbiosis is established, i.e., during infection, and more specifically in the chemotaxis of the symbiont. Phylogenetic analysis shows that the distribution of GlcP among cyanobacteria is likely influenced by horizontal gene transfer, but also that it is not correlated with symbiotic competence. Instead, regulatory patterns of the transporter in Nostoc punctiforme likely constitute symbiosis specific adaptations. PMID:24675169

  19. The role of sulfur in osmoregulation and salinity tolerance in cyanobacteria, algae, and plants

    NASA Technical Reports Server (NTRS)

    Yopp, J. H.

    1985-01-01

    Organosulfur compounds are involved in osmoregulation and salinity tolerance in some cyanobacteria and photosynthetic eukaryotes. Glycinebetaine, the osmolyte of the halotolerant cyanobacterium, Aphanothece halophytica, requires the sulfonium compound. S-adenosyl-methionine (SAM) for its synthesis. Glutamate is the nitrogen source, SAM is the methyl carbon and serine the carbon backbone source of this unique osmolyte. Inhibitor studies suggest that photorespiration interacts with sulfur metabolism to control betaine synthesis in cyanobacteria. The limiting factor for SAM synthesis is formate from photorespiration. SAM is, in turn, the methyl donor for betaine synthesis from serine. The nitrogen component of serine is from glutamate. Betaine synthesis is hypothesized to be regulated via potassium. The biosynthesis of dimethyl-B-propiothetin (DMPT, which is the same as beta-dimethyl sulfonioprpionate) and diacylsulfoquinovosylglycerol were elucidated as having their roles in osmoregulation and salinity tolerance. The relation between these sulfolipids and the sulfur cycle was discussed.

  20. Occurrence of 3-hydroxy acids in microalgae and cyanobacteria and their geochemical significance

    NASA Astrophysics Data System (ADS)

    Matsumoto, Genki I.; Nagashima, Hideyuki

    1984-08-01

    3-Hydroxy acids were detected in pure cultured microalgae: Chlorophyta— Chlamydomonas reinhardtii and Chlorella pyrenoidosa and Rhodophyta— Cyanidium caldarium (two strains), and cyanobacteria (Cyanophyta)— Anacystis nidulans, Phormidium foveolarum, Anabaena variabilis and Oscillatoria sp. Normal and branched (iso and anteiso) 3-hydroxy acids in the ranges of C 8-C 26 were found in all the samples studied at concentrations ranging from 0.036 to 2.3 and 0.000 to 0.12 mg g -1 of dry sample, respectively. The major constituents were generally even-carbon numbered normal acids with carbon chain lengths below C 20. Microalgae and cyanobacteria may be the important sources of 3-hydroxy acids in natural environments.

  1. [Algal biotoxins in Dialysis Water: a risk not managed].

    PubMed

    Ferrante, Margherita; Zuccarello, Pietro; Garufi, Angela; Cristaldi, Antonio; Oliveri Conti, Gea

    2016-01-01

    A literature review was performed to retrieve updated information on the quality of dialysis water, with a focus on the emerging problem of the presence of algal toxins (microcystins) produced by cyanobacteria. Current legislation was examined as well as studies conducted to date in different geographic areas. In this article, the authors present review results along with recommendations to operators and managers of dialysis units, for preventing possible risks for patients. PMID:27077559

  2. Unusual Symbiotic Cyanobacteria Association in the Genetically Diverse Intertidal Marine Sponge Hymeniacidon perlevis (Demospongiae, Halichondrida)

    PubMed Central

    Alex, Anoop; Vasconcelos, Vitor; Tamagnini, Paula; Santos, Arlete; Antunes, Agostinho

    2012-01-01

    Cyanobacteria represent one of the most common members of the sponge-associated bacterial community and are abundant symbionts of coral reef ecosystems. In this study we used Transmission Electron Microscopy (TEM) and molecular techniques (16S rRNA gene marker) to characterize the spatial distribution of cyanobionts in the widely dispersed marine intertidal sponge Hymeniacidon perlevis along the coast of Portugal (Atlantic Ocean). We described new sponge associated cyanobacterial morphotypes (Xenococcus-like) and we further observed Acaryochloris sp. as a sponge symbiont, previously only reported in association with ascidians. Besides these two unique cyanobacteria, H. perlevis predominantly harbored Synechococcus sp. and uncultured marine cyanobacteria. Our study supports the hypothesis that the community of sponge cyanobionts varies irrespective of the geographical location and is likely influenced by seasonal fluctuations. The observed multiple cyanobacterial association among sponges of the same host species over a large distance may be attributed to horizontal transfer of symbionts. This may explain the absence of a co-evolutionary pattern between the sponge host and its symbionts. Finally, in spite of the short geographic sampling distance covered, we observed an unexpected high intra-specific genetic diversity in H. perlevis using the mitochondrial genes ATP6 (π = 0.00177), COI (π = 0.00241) and intergenic spacer SP1 (π = 0.00277) relative to the levels of genetic variation of marine sponges elsewhere. Our study suggests that genotypic variation among the sponge host H. perlevis and the associated symbiotic cyanobacteria diversity may be larger than previously recognized. PMID:23251637

  3. Phenotypic and Genotypic Comparison of Symbiotic and Free-Living Cyanobacteria from a Single Field Site

    PubMed Central

    West, N. J.; Adams, D. G.

    1997-01-01

    PCR amplification techniques were used to compare cyanobacterial symbionts from a cyanobacterium-bryophyte symbiosis and free-living cyanobacteria from the same field site. Thirty-one symbiotic cyanobacteria were isolated from the hornwort Phaeoceros sp. at several closely spaced locations, and 40 free-living cyanobacteria were isolated from the immediate vicinity of the same plants. One of the symbiotic isolates was a species of Calothrix, a genus not previously known to form bryophyte symbioses, and the remainder were Nostoc spp. Of the free-living strains, two were Calothrix spp., three were Chlorogloeopsis spp. and the rest were Nostoc spp. All of the symbiotic and all but one of the free-living strains were able to reconstitute the symbiosis with axenic cultures of both Phaeoceros and the liverwort Blasia sp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the regions flanking the 16S-23S rRNA internal transcribed spacer. With one exception, the two techniques produced complementary results and confirmed for the first time that a diversity of symbiotic cyanobacteria infect Phaeoceros in the field. Symbionts from adjacent colonies were different as often as they were the same, showing that the same thallus could be infected with many different cyanobacterial strains. Strains found to be identical by the techniques employed here were often found as symbionts in different thalli at the same locale but were never found free-living. Only one of the free-living strains, and none of the symbiotic strains, was found at more than one sample site, implying a highly localized distribution of strains. PMID:16535734

  4. Occurrence of Cyclic di-GMP-Modulating Output Domains in Cyanobacteria: an Illuminating Perspective

    PubMed Central

    Agostoni, Marco; Koestler, Benjamin J.; Waters, Christopher M.; Williams, Barry L.; Montgomery, Beronda L.

    2013-01-01

    ABSTRACT Microorganisms use a variety of metabolites to respond to external stimuli, including second messengers that amplify primary signals and elicit biochemical changes in a cell. Levels of the second messenger cyclic dimeric GMP (c-di-GMP) are regulated by a variety of environmental stimuli and play a critical role in regulating cellular processes such as biofilm formation and cellular motility. Cyclic di-GMP signaling systems have been largely characterized in pathogenic bacteria; however, proteins that can impact the synthesis or degradation of c-di-GMP are prominent in cyanobacterial species and yet remain largely underexplored. In cyanobacteria, many putative c-di-GMP synthesis or degradation domains are found in genes that also harbor light-responsive signal input domains, suggesting that light is an important signal for altering c-di-GMP homeostasis. Indeed, c-di-GMP-associated domains are often the second most common output domain in photoreceptors—outnumbered only by a histidine kinase output domain. Cyanobacteria differ from other bacteria regarding the number and types of photoreceptor domains associated with c-di-GMP domains. Due to the widespread distribution of c-di-GMP domains in cyanobacteria, we investigated the evolutionary origin of a subset of genes. Phylogenetic analyses showed that c-di-GMP signaling systems were present early in cyanobacteria and c-di-GMP genes were both vertically and horizontally inherited during their evolution. Finally, we compared intracellular levels of c-di-GMP in two cyanobacterial species under different light qualities, confirming that light is an important factor for regulating this second messenger in vivo. PMID:23943760

  5. How long did it take for life to begin and evolve to cyanobacteria?

    NASA Technical Reports Server (NTRS)

    Lazcano, A.; Miller, S. L.

    1994-01-01

    There is convincing paleontological evidence showing that stromatolite-building phototactic prokaryotes were already in existence 3.5 x 10(9) years ago. Late accretion impacts may have killed off life on our planet as late as 3.8 x 10(9) years ago. This leaves only 300 million years to go from the prebiotic soup to the RNA world and to cyanobacteria. However, 300 million years should be more than sufficient time. All known prebiotic reactions take place in geologically rapid time scales, and very slow prebiotic reactions are not feasible because the intermediate compounds would have been destroyed due to the passage of the entire ocean through deep-sea vents every 10(7) years or in even less time. Therefore, it is likely that self-replicating systems capable of undergoing Darwinian evolution emerged in a period shorter than the destruction rates of its components (<5 million years). The time for evolution from the first DNA/protein organisms to cyanobacteria is usually thought to be very long. However, the similarities of many enzymatic reactions, together with the analysis of the available sequence data, suggest that a significant number of the components involved in basic biological processes are the result of ancient gene duplication events. Assuming that the rate of gene duplication of ancient prokaryotes was comparable to today's present values, the development of a filamentous cyanobacterial-like genome would require approximately 7 x 10(6) years--or perhaps much less. Thus, in spite of the many uncertainties involved in the estimates of time for life to arise and evolve to cyanobacteria, we see no compelling reason to assume that this process, from the beginning of the primitive soup to cyanobacteria, took more than 10 million years.

  6. Translational control of small heat shock genes in mesophilic and thermophilic cyanobacteria by RNA thermometers

    PubMed Central

    Cimdins, Annika; Klinkert, Birgit; Aschke-Sonnenborn, Ursula; Kaiser, Friederike M; Kortmann, Jens; Narberhaus, Franz

    2014-01-01

    Cyanobacteria constitute a heterogeneous phylum of oxygen-producing, photosynthetic prokaryotes. They are susceptible to various stress conditions like heat, salt, or light stress, all inducing the cyanobacterial heat shock response (HSR). Cyanobacterial small heat shock proteins (sHsps) are known to preserve thylakoid membrane integrity under stress conditions, thereby protecting the photosynthesis machinery. In Synechocystis sp PCC 6803, synthesis of the sHsp Hsp17 is regulated by an RNA thermometer (RNAT) in the 5′-untranslated region (5′-UTR) of the hsp17 mRNA. RNATs are direct temperature sensors that control expression of many bacterial heat shock and virulence genes. They hinder translation at low temperatures by base pairing, thus blocking ribosome access to the mRNA.   To explore the temperature range in which RNATs act, we studied various RNAT candidates upstream of sHsp genes from mesophilic and thermophilic cyanobacteria. The mesophilic cyanobacteria Anabaena variabilis and Nostoc sp chromosomally encode two sHsps each. Reporter gene studies suggested RNAT-mediated post-transcriptional regulation of shsp expression in both organisms. Detailed structural analysis of the two A. variabilis candidates revealed two novel RNAT types. The first, avashort, regulates translation primarily by masking of the AUG translational start codon. The second, featuring an extended initial hairpin, thus named avalong, presumably makes use of complex tertiary interaction. The 5′-UTR of the small heat shock gene hspA in the thermophile Thermosynechococcus elongatus is predicted to adopt an extended secondary structure. Structure probing revealed that the ribosome binding site was blocked at temperatures below 55 °C. The results of this study demonstrate that cyanobacteria commonly use RNATs to control expression of their small heat shock genes. PMID:24755616

  7. Salinity effects on growth, photosynthetic parameters, and nitrogenase activity in estuarine planktonic cyanobacteria.

    PubMed

    Moisander, P H; McClinton, E; Paerl, H W

    2002-05-01

    Salinity has been suggested as being a controlling factor for blooms of N2-fixing cyanobacteria in estuaries. We tested the effect of salinity on the growth, N2 fixation, and photosynthetic activities of estuarine and freshwater isolates of heterocystous bloom-forming cyanobacteria. Anabaena aphanizomenoides and Anabaenopsis sp. were isolated from the Neuse River Estuary, North Carolina, and Cylindrospermopsis raciborskii from Lakes Dora and Griffin, central Florida. Salinity tolerance of these cyanobacteria was compared with that of two Nodularia strains from the Baltic Sea. We measured growth rates, N2 fixation (nitrogenase activity), and CO2 fixation at salinities between 0 and 20 g L(-1) NaCl. We also examined photosynthesis-irradiance relation-ships in response to salinity. Anabaenopsis maintained similar growth rates in the full range of salinities from 2 to 20 g L(-1) NaCl. Anabaena grew at up to 15 g L-', but the maximum salinity 20 g L(-1) NaCl was inhibitory. The upper limit for salinity tolerance of Cylindrospermopsis was 4 g L(-1) NaCl. Nodularia spp. maintained similar growth rates in the full range of salinities from 0 to 20 g L(-1) . Between 0 and 10 g L(-1), the growth rate of Nodularia spumigena was slower than that of the Neuse Estuary strains. In most strains, the sensitivity of nitrogenase activity and CO2 fixation to salinity appeared similar. Anabaenopsis, Anabaena, and the two Nodularia strains rapidly responded to NaCl by increasing their maximum photosynthetic rates (Pmn). Overall, both Neuse River Estuary and Baltic Sea strains showed an ability to acclimate to salt stress over short-(24 h) and long-term (several days to weeks) exposures. The study suggested that direct effect of salinity (as NaCl in these experiments) on cyanobacterial physiology does not alone explain the low frequency and magnitude of blooms of N2-fixing cyanobacteria in estuaries. PMID:12043002

  8. Translational control of small heat shock genes in mesophilic and thermophilic cyanobacteria by RNA thermometers.

    PubMed

    Cimdins, Annika; Klinkert, Birgit; Aschke-Sonnenborn, Ursula; Kaiser, Friederike M; Kortmann, Jens; Narberhaus, Franz

    2014-01-01

    Cyanobacteria constitute a heterogeneous phylum of oxygen-producing, photosynthetic prokaryotes. They are susceptible to various stress conditions like heat, salt, or light stress, all inducing the cyanobacterial heat shock response (HSR). Cyanobacterial small heat shock proteins (sHsps) are known to preserve thylakoid membrane integrity under stress conditions, thereby protecting the photosynthesis machinery. In Synechocystis sp PCC 6803, synthesis of the sHsp Hsp17 is regulated by an RNA thermometer (RNAT) in the 5'-untranslated region (5'-UTR) of the hsp17 mRNA. RNATs are direct temperature sensors that control expression of many bacterial heat shock and virulence genes. They hinder translation at low temperatures by base pairing, thus blocking ribosome access to the mRNA.   To explore the temperature range in which RNATs act, we studied various RNAT candidates upstream of sHsp genes from mesophilic and thermophilic cyanobacteria. The mesophilic cyanobacteria Anabaena variabilis and Nostoc sp chromosomally encode two sHsps each. Reporter gene studies suggested RNAT-mediated post-transcriptional regulation of shsp expression in both organisms. Detailed structural analysis of the two A. variabilis candidates revealed two novel RNAT types. The first, avashort, regulates translation primarily by masking of the AUG translational start codon. The second, featuring an extended initial hairpin, thus named avalong, presumably makes use of complex tertiary interaction. The 5'-UTR of the small heat shock gene hspA in the thermophile Thermosynechococcus elongatus is predicted to adopt an extended secondary structure. Structure probing revealed that the ribosome binding site was blocked at temperatures below 55 °C. The results of this study demonstrate that cyanobacteria commonly use RNATs to control expression of their small heat shock genes. PMID:24755616

  9. Genomes of Stigonematalean Cyanobacteria (Subsection V) and the Evolution of Oxygenic Photosynthesis from Prokaryotes to Plastids

    PubMed Central

    Dagan, Tal; Roettger, Mayo; Stucken, Karina; Landan, Giddy; Koch, Robin; Major, Peter; Gould, Sven B.; Goremykin, Vadim V.; Rippka, Rosmarie; Tandeau de Marsac, Nicole; Gugger, Muriel; Lockhart, Peter J.; Allen, John F.; Brune, Iris; Maus, Irena; Pühler, Alfred; Martin, William F.

    2013-01-01

    Cyanobacteria forged two major evolutionary transitions with the invention of oxygenic photosynthesis and the bestowal of photosynthetic lifestyle upon eukaryotes through endosymbiosis. Information germane to understanding those transitions is imprinted in cyanobacterial genomes, but deciphering it is complicated by lateral gene transfer (LGT). Here, we report genome sequences for the morphologically most complex true-branching cyanobacteria, and for Scytonema hofmanni PCC 7110, which with 12,356 proteins is the most gene-rich prokaryote currently known. We investigated components of cyanobacterial evolution that have been vertically inherited, horizontally transferred, and donated to eukaryotes at plastid origin. The vertical component indicates a freshwater origin for water-splitting photosynthesis. Networks of the horizontal component reveal that 60% of cyanobacterial gene families have been affected by LGT. Plant nuclear genes acquired from cyanobacteria define a lower bound frequency of 611 multigene families that, in turn, specify diazotrophic cyanobacterial lineages as having a gene collection most similar to that possessed by the plastid ancestor. PMID:23221676

  10. Cultural characteristics of chromium resistant unicellular cyanobacteria isolated from local environment in Pakistan

    NASA Astrophysics Data System (ADS)

    Hameed, Abdul; Hasnain, Shahida

    2005-12-01

    Many unicellular cyanobacteria were isolated from different places: fields, ponds, polluted water, and soils from Muredkey and Kasur tannery areas, near Lahore, Pakistan. Different media like BG 11 medium, Bold Basal medium, Chu's #10 medium and Gorham's medium, in standard forms and with slight variations of ingredients, and different pH, temperature and light regimes were checked for the optimum growth of the isolates. The isolation procedure was repeated with different concentrations of chromium to select the resistant strains. These selected strains grew on chromium of the range 100-200 μg/ml in BG 11 medium. Cyanobacteria were maintained in solid and liquid media with/without shaking. Cyanobacterial strains were collected from natural habitats that were accompanied by a diversified group of organisms including bacteria, protozoan, and rotifers etc. In order to eliminate these agents termed as contaminants, we used several methods including phenol treatment, use of antibiotic and careful manual picking of unicellular cyanobacteria. Resistance of these strains against different heavy metals (ZnSO4, MnSO4, NiSO4, CoCl2, Pb(NO3)3, CuSO4, HgCl2, AgNO3 and CdCl2) and antibiotics (erythromycin, streptomycin, kanamyci chloramphenicol, neomycin) was evaluated. Optimum temperature was 30°C with variable pH for the reduction of Cr6+ in to Cr3+ in majority of strains.

  11. Genomewide Analysis of Carotenoid Cleavage Dioxygenases in Unicellular and Filamentous Cyanobacteria

    PubMed Central

    Cui, Hongli; Wang, Yinchu; Qin, Song

    2012-01-01

    Carotenoid cleavage dioxygenases (CCDs) are a group of enzymes that catalyze the oxidative cleavage steps from carotenoids to various carotenoid cleavage products. Some ccd genes have been identified and encoded enzymes functionally characterized in many higher plants, but little in cyanobacteria. We performed a comparative analysis of ccd sequences and explored their distribution, classification, phylogeny, evolution, and structure among 37 cyanobacteria. Totally 61 putative ccd sequences were identified, which are abundant in Acaryochloris marina MBIC 11017, filamentous N2-fixing cyanobacteria, and unicellular cyanobacterial Cyanothece. According to phylogenetic trees of 16S rDNA and CCD, nced and ccd8 genes occur later than the divergence of ccd7, apco, and ccd1. All CCD enzymes share conserved basic structure domains constituted by a single loop formed with seven β-strands and one helix. In this paper, a general framework of sequence-function-evolution connection for the ccd has been revealed, which may provide new insight for functional investigation. PMID:22474409

  12. Ribosomal RNA gene fragments from fossilized cyanobacteria identified in primary gypsum from the late Miocene, Italy.

    PubMed

    Panieri, G; Lugli, S; Manzi, V; Roveri, M; Schreiber, B C; Palinska, K A

    2010-03-01

    Earth scientists have searched for signs of microscopic life in ancient samples of permafrost, ice, deep-sea sediments, amber, salt and chert. Until now, evidence of cyanobacteria has not been reported in any studies of ancient DNA older than a few thousand years. Here, we investigate morphologically, biochemically and genetically primary evaporites deposited in situ during the late Miocene (Messinian) Salinity Crisis from the north-eastern Apennines of Italy. The evaporites contain fossilized bacterial structures having identical morphological forms as modern microbes. We successfully extracted and amplified genetic material belonging to ancient cyanobacteria from gypsum crystals dating back to 5.910-5.816 Ma, when the Mediterranean became a giant hypersaline brine pool. This finding represents the oldest ancient cyanobacterial DNA to date. Our clone library and its phylogenetic comparison with present cyanobacterial populations point to a marine origin for the depositional basin. This investigation opens the possibility of including fossil cyanobacterial DNA into the palaeo-reconstruction of various environments and could also be used to quantify the ecological importance of cyanobacteria through geological time. These genetic markers serve as biosignatures providing important clues about ancient life and begin a new discussion concerning the debate on the origin of late Miocene evaporites in the Mediterranean. PMID:20059556

  13. Bloom Dynamics of Cyanobacteria and Their Toxins: Environmental Health Impacts and Mitigation Strategies

    PubMed Central

    Rastogi, Rajesh P.; Madamwar, Datta; Incharoensakdi, Aran

    2015-01-01

    Cyanobacteria are ecologically one of the most prolific groups of phototrophic prokaryotes in both marine and freshwater habitats. Both the beneficial and detrimental aspects of cyanobacteria are of considerable significance. They are important primary producers as well as an immense source of several secondary products, including an array of toxic compounds known as cyanotoxins. Abundant growth of cyanobacteria in freshwater, estuarine, and coastal ecosystems due to increased anthropogenic eutrophication and global climate change has created serious concern toward harmful bloom formation and surface water contamination all over the world. Cyanobacterial blooms and the accumulation of several cyanotoxins in water bodies pose severe ecological consequences with high risk to aquatic organisms and global public health. The proper management for mitigating the worldwide incidence of toxic cyanobacterial blooms is crucial for maintenance and sustainable development of functional ecosystems. Here, we emphasize the emerging information on the cyanobacterial bloom dynamics, toxicology of major groups of cyanotoxins, as well as a perspective and integrative approach to their management. PMID:26635737

  14. Improving polyglucan production in