| abundance and distribution of major groups of diazotrophic cyanobacteria and their potential contribution to n₂ fixation in the tropical atlantic ocean. | the abundances of six n₂-fixing cyanobacterial phylotypes were profiled at 22 stations across the tropical atlantic ocean during june 2006, and used to model the contribution of the diazotrophs to n₂ fixation. diazotroph abundances were measured by targeting the nifh gene of trichodesmium, unicellular groups a, b, c (ucyn-a, ucyn-b and ucyn-c), and diatom-cyanobiont symbioses hemiaulus-richelia, rhizosolenia-richelia and chaetoceros-calothrix. west to east gradients in temperature, salinity and ... | 2010 | 20678117 |
| phylogenetic and molecular clock inferences of cyanobacterial strains within rivulariaceae from distant environments. | heterocyst-forming cyanobacteria are important players at both evolutionary and ecological scales, but to date it has been difficult to establish their phylogenetic affiliations. we present data from a phylogenetic and molecular clock analysis of heterocystous cyanobacteria within the family rivulariaceae, including the genera calothrix, rivularia, gloeotrichia and tolypothrix. the strains were isolated from distant geographic regions including fresh and brackish water bodies, microbial mats fro ... | 2011 | 21208268 |
| phenotypic variability and phylogenetic relationships of tolypothrix and calothrix (nostocales, cyanobacteria) from running water. | the taxonomy of heterocystous cyanobacteria belonging to the genera calothrix and tolypothrix has long been a matter of debate, but their phylogenetic relationships are still not well understood. our aim was to compare the phylogeny and morphology of members of these genera, which exhibit basal-apical polarity. a phylogeny was reconstructed on the basis of 16s rrna gene sequences and compared with the morphological characterisation of new isolates and environmental samples. strains isolated from ... | 2011 | 21317280 |
| nitrogen fixation and transfer in open ocean diatom-cyanobacterial symbioses. | many diatoms that inhabit low-nutrient waters of the open ocean live in close association with cyanobacteria. some of these associations are believed to be mutualistic, where n(2)-fixing cyanobacterial symbionts provide n for the diatoms. rates of n(2) fixation by symbiotic cyanobacteria and the n transfer to their diatom partners were measured using a high-resolution nanometer scale secondary ion mass spectrometry approach in natural populations. cell-specific rates of n(2) fixation (1.15-71.5? ... | 2011 | 21451586 |
| Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance. | Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30-ádays. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirm ... | 2011 | 21732035 |
| observations on the mechanisms of attachment of some marine fouling blue-green algae. | using scanning electron microscopy (sem), differential interference contrast microscopy (dicm) and cytochemical staining techniques, preliminary observations have been made on the mechanisms of attachment of some common, marine, benthic fouling blue-green algae ("cyanobacteria") isolated into culture from various toxic and non-toxic surfaces in langstone harbour, south coast of england. blue-green algae investigated included species of calothrix, dermocarpa, plectonema, phormidium and xenococcus ... | 1996 | 22115109 |
| Morphological and molecular characterization of Calothrix isolates obtained from diverse environments in India. | Abstract-Thirty cyanobacterial strains of Calothrix (family Rivulariaceae) isolated from diverse geographical regions of India were analyzed using morphological and molecular approaches. Most of the isolates were planktonic while some grew benthically. Significant differences were observed with regard to the shape and size of the vegetative cells, heterocysts, and akinetes. Analyses of molecular polymorphisms using Restriction Fragment Length Polymorphisms (RFLP) of 16S rRNA genes with the refer ... | 2011 | 21861379 |
| morphological and genetic diversity of symbiotic cyanobacteria from cycads. | the morphological and genetic diversity of cyanobacteria associated with cycads was examined using pcr amplification techniques and 16s rrna gene sequence analysis. eighteen symbiotic cyanobacteria were isolated from different cycad species. one of the symbiotic isolates was a species of calothrix, a genus not previously reported to form symbioses with cycadaceae family, and the remainder were nostoc spp. axenic cyanobacterial strains were compared by dna amplification using pcr with either shor ... | 2010 | 20473963 |
| host selection of symbiotic cyanobacteria in 31 species of the australian cycad genus: macrozamia (zamiaceae). | the nitrogen-fixing cyanobacterium nostoc is a commonly occurring terrestrial and aquatic cyanobacterium often found in symbiosis with a wide range of plant, algal, and fungal species. we investigated the diversity of cyanobacterial species occurring within the coralloid roots of different macrozamia cycad species at diverse locations throughout australia. in all, 74 coralloid root samples were processed and 56 endosymbiotic cyanobacteria were cultured. dna was isolated from unialgal cultures an ... | 2010 | 20459320 |
| physiological characterization and electron microscopic investigation of cyanobacteria associated with wheat rhizosphere. | physiological attributes of a set of cyanobacterial strains, isolated from the rhizosphere of wheat (var. hd 2687), identified as belonging to the genera calothrix (n = 3), westiellopsis (1), hapalosiphon (2) and nostoc (2), were axenized and evaluated. the concentrated culture filtrates of three cyanobacterial strains - c. ghosei, h. intricatus and nostoc sp. were able to enhance germination percentage, radicle and coleoptile length in inhibition experiments with wheat seeds. indole-3-acetic ac ... | 2009 | 19330544 |
| removal of colour from textile effluent using cyanobacterial biomass. | the cyanobacterial species were isolated from fresh water pond of gura-vishnoiyan and were tested for their ability to decolourise the textile effluent. the reduction in colour of textile effluent with the use of dry biomass of cylindrospermum indicum, nostoc calcicola, calothrix weberi was comparatively observed after 2, 4 and 6 days, but maximum colour absorption was observed after 6 days. calothrix weberi was found the most effective species of cyanobacteria, which can remove the colour inten ... | 2008 | 19295090 |
| very-long-chain iso and anteiso branched fatty acids in n-acylphosphatidylethanolamines from a natural cyanobacterial mat of calothrix sp. | a combination of tlc, esi-ms/ms and gc-ms was used to identify unusual molecular species of n-acylphosphatidylethanolamines containing very-long-chain anteiso branched fatty acids (vlcfas) from calothrix sp. collected in antarctica and determine their component vlcfa up to 33-methyltetratriacontanoic acid as picolinyl ester derivatives using gc-ms. | 2009 | 19272619 |
| epilithic cyanobacterial communities of a marine tropical beach rock (heron island, great barrier reef): diversity and diazotrophy. | the diversity and nitrogenase activity of epilithic marine microbes in a holocene beach rock (heron island, great barrier reef, australia) with a proposed biological calcification "microbialite" origin were examined. partial 16s rrna gene sequences from the dominant mat (a coherent and layered pink-pigmented community spread over the beach rock) and biofilms (nonstratified, differently pigmented microbial communities of small shallow depressions) were retrieved using denaturing gradient gel elec ... | 2007 | 17416688 |
| homologous expression of a bacterial phytochrome. the cyanobacterium fremyella diplosiphon incorporates biliverdin as a genuine, functional chromophore. | bacteriophytochromes constitute a light-sensing subgroup of sensory kinases with a chromophore-binding motif in the n-terminal half and a c-terminally located histidine kinase activity. the cyanobacterium fremyella diplosiphon (also designated calothrix sp.) expresses two sequentially very similar bacteriophytochromes, cyanobacterial phytochrome a (cpha) and cyanobacterial phytochrome b (cphb). cyanobacterial phytochrome a has the canonical cysteine residue, by which covalent chromophore attachm ... | 2007 | 17388813 |
| rhodopsin(s) in eubacteria. | while the biochemical basis of photosynthesis by bacteriochlorophyll-based reaction centres in purple phototrophic eubacteria and retinal-based bacteriorhodopsin in the archaebacterium halobacterium salinarium has been elucidated in great detail, much less is known about photosensory signal transduction; this is especially the case for eubacteria. recent findings on two different photosensory proteins in two different eubacteria, which both show clear resemblances to the rhodopsins, will be pres ... | 1995 | 17023324 |
| nitrogen fixation associated with the new zealand mangrove (avicennia marina (forsk.) vierh. var. resinifera (forst. f.) bakh.). | nitrogenase activity in mangrove forests at two locations in the north island, new zealand, was measured by acetylene reduction and n(2) uptake. nitrogenase activity (c(2)h(2) reduction) in surface sediments 0 to 10 mm deep was highly correlated (r = 0.91, n = 17) with the dry weight of decomposing particulate organic matter in the sediment and was independent of light. the activity was not correlated with the dry weight of roots in the top 10 mm of sediment (r = -0.01, n = 13). seasonal and sam ... | 1985 | 16346771 |
| characterization of nitrogen-fixing cyanobacteria in the brazilian amazon floodplain. | the diversity of the free-living nitrogen-fixing cyanobacterial community in the floodplain sediments along the solimões and amazon rivers and some of their tributaries (japurá, negro and madeira) was investigated. five cyanobacterial genera were morphologically identified, four of which (nostoc, calothrix, cylindrospermum and fischerella) have not previously been isolated from the brazilian amazon floodplain. nostoc strains were the most commonly found heterocyst-forming cyanobacteria. five str ... | 2005 | 16289234 |
| physiological and molecular diversity of feather moss associative n2-fixing cyanobacteria. | cyanobacteria colonizing the feather moss pleurozium schreberi were isolated from moss samples collected in northern sweden and subjected to physiological and molecular characterization. morphological studies of isolated and moss-associated cyanobacteria were carried out by light microscopy. molecular tools were used for cyanobacteria identification, and a reconstitution experiment of the association between non-associative mosses and cyanobacteria was conducted. the influence of temperature on ... | 2005 | 16263908 |
| a high proportion of baltic sea benthic cyanobacterial isolates contain apoptogens able to induce rapid death of isolated rat hepatocytes. | to assess the potential hepatotoxicity of benthic cyanobacteria, we isolated 41 strains from the baltic sea. the bacteria were differentially extracted with solvents of decreasing polarity. the extracts were tested for ability to induce death of primary rat hepatocytes in suspension culture. mainly morphological criteria were used to discriminate between cell death with apoptotic features (shrinkage, chromatin hypercondensation, budding) or necrotic features (swelling, loss of plasma membrane in ... | 2005 | 15990143 |
| community phylogenetic analysis of moderately thermophilic cyanobacterial mats from china, the philippines and thailand. | most community molecular studies of thermophilic cyanobacterial mats to date have focused on synechococcus occurring at temperatures of approximately 50-65 degrees c. these reveal that molecular diversity exceeds that indicated by morphology, and that phylogeographic lineages exist. the moderately thermophilic and generally filamentous cyanobacterial mat communities occurring at lower temperatures have not previously been investigated at the community molecular level. here we report community di ... | 2005 | 15970994 |
| benthic cyanobacteria from the baltic sea contain cytotoxic anabaena, nodularia, and nostoc strains and an apoptosis-inducing phormidium strain. | benthic cyanobacteria from aquatic environments have been reported to produce biologically active metabolites. however, the toxicity and other biological activities of benthic cyanobacteria from the baltic sea are not well known. we determined the biological activities of 21 anabaena, calothrix, nodularia, nostoc, and phormidium strains isolated from benthic littoral habitats of the baltic sea. we studied whether benthic cyanobacterial extracts caused cytotoxicity by necrosis or induced apoptosi ... | 2005 | 15892066 |
| a correlation matrix of alkaline phosphatase and sporulation in diazotrophic cyanobacteria and its thermo-tolerant mutant. | alkaline phosphatase (phosphomonoesterase i.e. pmease) activity in heterocystous cyanobacteria anabaena flos-aquae, nostoc calcicola, calothrix brevissima, scytonema javanicum and hapalosiphon intricatus is known to be temperature and ph dependent. maximum level of enzyme activity was recorded at either 35 degrees c or 37.5 degrees c. also, the cell bound phosphomonoesterase enzyme was shown to exhibit ph optima of 10.0 or 10.2. a thermo-tolerant (tr) mutant isolated after mnng (n-methyl-n'-nitr ... | 2004 | 15790075 |
| modulation of pigment profiles of calothrix elenkenii in response to environmental changes. | cyanobacteria are versatile tetrapyrrole synthesizers that can regulate their tetrapyrrole content and composition in response to environmental signals. the present investigation analyses the interplay between light and dark regimes (continuous light, light-dark cycles (16:8) and continuous darkness) and aerobic, air-tight, and anaerobic environments (argon-enriched), on the relative composition of various pigments and growth attributes of calothrix elenkenii as a prelude to exploiting c. elenke ... | 2004 | 15535122 |
| synthesis, electrochemistry, and bioactivity of the cyanobacterial calothrixins and related quinones. | the calothrixins are quinone-based natural products isolated from calothrix cyanobacteria which show potent antiproliferative properties against several cancer cell lines. preliminary mechanistic studies suggest that the biological mode of action of the calothrixins may be linked to their ability to undergo redox cycling. in this study we compare the bioactivities of the calothrixins with those of structurally related quinones in order to identify the structural features in the calothrixins esse ... | 2004 | 15369400 |
| volatile organic compound (voc) analysis and sources of limonene, cyclohexanone and straight chain aldehydes in axenic cultures of calothrix and plectonema. | the volatile organic compounds (vocs) in four standing cultures of axenic benthic cyanobacteria (calothrix and plectonema) were studied by gc/ms analysis. to verify the biogenic origin of the vocs, 13c-labelling experiments were performed, and the differences in labelling were used to differentiate between biogenic and non-biogenic sources. strongly labelled biogenic compounds were derived from the shikimate (cresol, skatole), isoprenoid (beta-cyclocitral, beta-ionone, geosmin) and fatty acid pa ... | 2004 | 15237606 |
| biochemical effect of carbaryl on oxidative stress, antioxidant enzymes and osmolytes of cyanobacterium calothrix brevissima. | carbaryl is used in indian agriculture for control of rice field pests and it is next to benzene hexachloride in pesticide consumption. in present study, carbaryl (0, 10, 20, 30 and 40 mg/l) induced toxic effects were observed after 21 days exposure on a non target rice field biofertilizer calothrix brevissima with special reference to oxidative stress, antioxidant enzymes and osmolytes. at 40 mg/l carbaryl the decrease in carotenoid, chlorophyll, phycobilin and protein were 63%, 43%, 40% and 40 ... | 2011 | 21979138 |
| antibiotic production by the cyanobacteria oscillatoria angustissima and calothrix parietina. | the accumulation of antibiotic in the medium is temperature dependent and not in direct proportion to growth parameters. the cyanobacterial product suppressed growth of some natural isolates of cyanobacteria and green algae. it inhibits the growth rate and oxygen evolution of the green alga, chlorella fusca. the antibiotic also inhibits the growth of bacteria and some fungi, especially the dermatophytes. generally eukaryotic organisms were less sensitive than prokaryotic. experimental mice were ... | 1999 | 21781939 |