| phylogenetic relationships of nonaxenic filamentous cyanobacterial strains based on 16s rrna sequence analysis. | in order to determine the nearly complete 16s rrna gene sequences of cyanobacteria originating from nonaxenic cultures, a cyanobacterium-specific oligonucleotide probe was developed to distinguish polymerase chain reaction (pcr) products of the cyanobacterial rrna operons from those resulting from amplification of contaminating bacteria. using this screening method the 16s rrna genes of four nonaxenic filamentous cyanobacterial strains belonging to the genera leptolyngbya and oscillatoria were c ... | 1996 | 8919871 |
| the presence and expression of hetr in the non-heterocystous cyanobacterium symploca pcc 8002. | the filamentous cyanobacteria symploca pcc 8002 (symploca) and trichodesmium spp. fix nitrogen aerobically in the light in a light/dark cycle, without forming specialized thick-walled cells (heterocysts). even though they do not form heterocysts, we amplified and sequenced a segment of a key regulatory gene in heterocyst differentiation, the hetr gene, from symploca, trichodesmium erythraeum and leptolyngbya pcc 73110 (which fixes nitrogen anaerobically) using degenerate oligonucleotides. the tr ... | 1998 | 9835026 |
| structural interactions among epilithic cyanobacteria and heterotrophic microorganisms in roman hypogea. | abstract phototrophic microbial communities present in the roman catacombs were characterized and different species of terrestrial epilithic cyanobacteria were found to occur as dominant organisms. eucapsis, leptolyngbya, scytonema, and fischerella were the most frequently encountered cyanobacterial taxa, while a few species of green algae and the diatom diadesmis gallica occurred in minor amounts. streptomyces strains, a few genera of eubacteria, and to a lesser extent fungi were always present ... | 1999 | 10541786 |
| a complex photoreceptive structure in the cyanobacterium leptolyngbya sp. | among the terrestrial epilithic cyanobacteria isolated from roman hypogea at extremely low light intensity, a non-heterocystous strain, belonging to the genus leptolyngbya, showed a marked photobehavior. these red cyanobacteria possess an orange spot at the tip of the apical cell. micro-spectrophotometric analysis of this tip showed an absorption spectrum with two bands, centered at 456 and 504 nm, respectively. experiments on photo-orientation impairment of these cells, and micro-spectrophotome ... | 2000 | 10568228 |
| [cyanobacteria as indicators of organic contamination]. | in two costa rican rivers used as receptors for domestic sewage, treated by primary stabilization ponds, were taken a total of 28 samplings located at the pond exit and at three different sites in each river: 100 m before the ponds discharge, at the discharge and 100 m after the discharge. these sampling were done for a five and a half years including dry and rainy seasons. in each sampling site, samples were collected of five different substrates: stones, submerge and semi submerge vegetation, ... | 1999 | 10883326 |
| cyanobacterial diversity in extreme environments in baja california, mexico: a polyphasic study. | cyanobacterial diversity from two geographical areas of baja california sur, mexico, were studied: bahia concepcion, and ensenada de aripez. the sites included hypersaline ecosystems, sea bottom, hydrothermal springs, and a shrimp farm. in this report we describe four new morphotypes, two are marine epilithic from bahia concepcion, dermocarpa sp. and hyella sp. the third, geitlerinema sp., occurs in thermal springs and in shrimp ponds, and the fourth, tychonema sp., is from a shrimp pond. the pa ... | 2001 | 12051567 |
| molecular characterization of endolithic cyanobacteria inhabiting exposed dolomite in central switzerland. | the phototrophic microbial community inhabiting exposed dolomite in the alpine piora valley (switzerland) forms a distinct endolithic bilayer that features adjacent red dolomite (exterior) and green dolomite (interior) layers that are c. 0.5-1 mm below the rock surface. characterization of the community, with an emphasis on cyanobacteria, was conducted with culture-dependent and -independent approaches. direct microscopy of green dolomite revealed four distinct morphotypes consistent with chloro ... | 2003 | 12823194 |
| ecosystems on ice: the microbial ecology of markham ice shelf in the high arctic. | microbial communities occur throughout the cryosphere in a diverse range of ice-dominated habitats including snow, sea ice, glaciers, permafrost, and ice clouds. in each of these environments, organisms must be capable of surviving freeze-thaw cycles, persistent low temperatures for growth, extremes of solar radiation, and prolonged dormancy. these constraints may have been especially important during global cooling events in the past, including the precambrian glaciations. one analogue of these ... | 2004 | 15094087 |
| microbial diversity of extant stromatolites in the hypersaline marine environment of shark bay, australia. | stromatolites have been present on earth, at various levels of distribution and diversity, for more than 3 billion years. today, the best examples of stromatolites forming in hypersaline marine environments are in hamelin pool at shark bay, western australia. despite their evolutionary significance, little is known about their associated microbial communities. using a polyphasic approach of culture-dependent and culture-independent methods, we report the discovery of a wide range of microorganis ... | 2004 | 15344935 |
| development of a universal microarray based on the ligation detection reaction and 16s rrna gene polymorphism to target diversity of cyanobacteria. | 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 develop ... | 2004 | 15574913 |
| variable selection pressures across lineages in trichodesmium and related cyanobacteria based on the heterocyst differentiation protein gene hetr. | due to the irreversible inhibition of nitrogenase by o2, n2 fixation is incompatible with the oxygenic photosynthesis of cyanobacteria. these organisms have therefore evolved various strategies for growing diazotrophically. one group of n2-fixing cyanobacteria has specialized cells, heterocysts, which contain the nitrogenase, lack the oxygenic photosystem ii, and are virtually anoxic inside as the result of respiratory activity and a thick glycolipid cell wall. the hetr gene encodes a serine pro ... | 2005 | 15716028 |
| populations of exopolysaccharide-producing cyanobacteria and diatoms in the mucilaginous benthic aggregates of the tyrrhenian sea (tuscan archipelago). | the microalgal community of benthic mucilages sampled in various sites of the tuscan archipelago during the period may 1999-july 2002, was always dominated by diatoms. synedra, licmophora and navicula were the most frequently found genera, their presence having been observed within all the period under study; other ten genera of diatoms were found in the benthic mucilages, but their presence was dependent on the month and the year of observation. as concerns the cyanobacterial community, the fil ... | 2005 | 16271382 |
| characterization of functional bacterial groups in a hypersaline microbial mat community (salins-de-giraud, camargue, france). | a photosynthetic microbial mat was investigated in a large pond of a mediterranean saltern (salins-de-giraud, camargue, france) having water salinity from 70 per thousand to 150 per thousand (w/v). analysis of characteristic biomarkers (e.g., major microbial fatty acids, hydrocarbons, alcohols and alkenones) revealed that cyanobacteria were the major component of the pond, in addition to diatoms and other algae. functional bacterial groups involved in the sulfur cycle could be correlated to thes ... | 2004 | 16329855 |
| differential operation of dual protochlorophyllide reductases for chlorophyll biosynthesis in response to environmental oxygen levels in the cyanobacterium leptolyngbya boryana. | most oxygenic phototrophs, including cyanobacteria, have two structurally unrelated protochlorophyllide (pchlide) reductases in the penultimate step of chlorophyll biosynthesis. one is light-dependent pchlide reductase (lpor) and the other is dark-operative pchlide reductase (dpor), a nitrogenase-like enzyme assumed to be sensitive to oxygen. very few studies have been conducted on how oxygen-sensitive dpor operates in oxygenic phototrophic cells. here, we report that anaerobic conditions are re ... | 2006 | 17028153 |
| microbial communities on glacier surfaces in svalbard: impact of physical and chemical properties on abundance and structure of cyanobacteria and algae. | 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 quan ... | 2006 | 17072679 |
| molecular characterization of marine cyanobacteria from the indian subcontinent deduced from sequence analysis of the phycocyanin operon (cpcb-igs-cpca) and 16s-23s its region. | molecular characterization of ten marine cyanobacterial isolates belonging to the order oscillatoriales was carried out using the phycocyanin locus (cpcba-igs) and the 16s-23s internally transcribed spacer region. dna sequences from the phycocyanin operon discriminated ten genotypes, which corresponded to seven morphotypes identified by traditional microscopic analysis. the cpcb coding region revealed 17 % nucleotide variation, while cpca exhibited 29 % variation across the studied species. phyl ... | 2006 | 17205038 |
| a long-term copper exposure on freshwater ecosystem using lotic mesocosms: primary producer community responses. | copper is commonly used as an algicide and plant herbicide in the aquatic environment. despite of its frequent application in rivers, ponds and lakes, few studies have been performed at the ecosystem level on primary producers' communities. a long-term lotic mesocosms study was carried on, in 20m long channels, under environmentally realistic concentrations of copper (0, 5, 25 and 75 microgl(-1)) delivered continuously for 18 months. results showed significant effects at the 25 and 75 microgl(-1 ... | 2007 | 17239970 |
| the presence of the cyanobacterial toxin microcystin in black band disease of corals. | black band disease (bbd) is a migrating, cyanobacterial dominated, sulfide-rich microbial mat that moves across coral colonies lysing coral tissue. while it is known that bbd sulfate-reducing bacteria contribute to bbd pathogenicity by production of sulfide, additional mechanisms of toxicity may be involved. using hplc/ms, the cyanotoxin microcystin was detected in 22 field samples of bbd collected from five coral species on nine reefs of the wider caribbean (florida keys and bahamas). two cyano ... | 2007 | 17506829 |
| molecular detection and ecological significance of the cyanobacterial genera geitlerinema and leptolyngbya in black band disease of corals. | black band disease (bbd) is a pathogenic, sulfide-rich microbial mat dominated by filamentous cyanobacteria that infect corals worldwide. we isolated cyanobacteria from bbd into culture, confirmed their presence in the bbd community by using denaturing gradient gel electrophoresis (dgge), and demonstrated their ecological significance in terms of physiological sulfide tolerance and photosynthesis-versus-irradiance values. twenty-nine bbd samples were collected from nine host coral species, four ... | 2007 | 17601818 |
| cyanobacteria as bioreactors for the synthesis of au, ag, pd, and pt nanoparticles via an enzyme-mediated route. | common anabaena, calothrix, and leptolyngbya cyanobacteria are shown to form au, ag, pd, and pt nanoparticles of well-controlled size. these nanoparticles are synthesized intra-cellularly, and naturally released in the culture medium, where they are stabilized by algal polysaccharides, allowing their easy recovery. the size of the recovered particles as well as the reaction yield is shown to depend on the cyanobacteria genus. investigations of nanoparticle formation indicate that the intracellul ... | 2007 | 17685286 |
| cyanobacterial composition of microbial mats from an australian thermal spring: a polyphasic evaluation. | cyanobacterial composition of microbial mats from an alkaline thermal spring issuing at 43-71 degrees c from tropical north-eastern australia are described using a polyphasic approach. eight genera and 10 species from three cyanobacterial orders were identified based on morphological characters. these represented taxa previously known as thermophilic from other continents. ultrastructural analysis of the tower mats revealed two filamentous morphotypes contributed the majority of the biomass. bot ... | 2008 | 18081588 |
| coibamide a, a potent antiproliferative cyclic depsipeptide from the panamanian marine cyanobacterium leptolyngbya sp. | coibamide a (1) is a new, potent antiproliferative depsipeptide which was isolated from a marine leptolyngbya cyanobacterium collected from the coiba national park, panama. the planar structure of 1 was elucidated by a combination of nmr spectroscopy and mass spectrometry. exhaustive 1d and 2d nmr spectroscopy included natural abundance 15n and variable temperature experiments; mass spectrometry included tof-esi-msn and ft-msn experiments. chemical degradation followed by chiral hplc- and gc-ms ... | 2008 | 18444611 |
| reproducing stone monument photosynthetic-based colonization under laboratory conditions. | in order to understand the biodeterioration process occurring on stone monuments, we analyzed the microbial communities involved in these processes and studied their ability to colonize stones under controlled laboratory experiments. in this study, a natural green biofilm from a limestone monument was cultivated, inoculated on stone probes of the same lithotype and incubated in a laboratory chamber. this incubation system, which exposes stone samples to intermittently sprinkling water, allowed t ... | 2008 | 18768211 |
| cytomorphological and genetic characterization of troglobitic leptolyngbya strains isolated from roman hypogea. | six leptolyngbya strains, isolated from the archaeological surfaces of hypogean sites, were phenotypically and genetically characterized by light and electron microscopy and 16s rrna gene and 16s-23s internally transcribed spacer (its) sequencing. three phycoerythrin-rich (red) and three phycocyanin-rich (green) isolates were assigned to different operational taxonomic units (otus). among the green isolates, one strain showed an otu intraspecific variation due to differences in the its sequences ... | 2009 | 19047394 |
| adaptation of cyanobacteria to the sulfide-rich microenvironment of black band disease of coral. | black band disease (bbd) is a cyanobacteria-dominated microbial mat that migrates across living coral colonies lysing coral tissue and leaving behind exposed coral skeleton. the mat is sulfide-rich due to the presence of sulfate-reducing bacteria, integral members of the bbd microbial community, and the sulfide they produce is lethal to corals. the effect of sulfide, normally toxic to cyanobacteria, on the photosynthetic capabilities of five bbd cyanobacterial isolates of the genera geitlerinema ... | 2009 | 19049501 |
| molecular characterization of an endolithic microbial community in dolomite rock in the central alps (switzerland). | endolithic microorganisms colonize the pores in exposed dolomite rocks in the piora valley in the swiss alps. they appear as distinct grayish-green bands about 1-8 mm below the rock surface. based on environmental small subunit ribosomal rna gene sequences, a diverse community driven by photosynthesis has been found. cyanobacteria (57 clones), especially the genus leptolyngbya, form the functional basis for an endolithic community which contains a wide spectrum of so far not characterized specie ... | 2009 | 19172216 |
| notes on freshwater and terrestrial algae from ny-alesund, svalbard (high arctic sea area). | field survey of algae and cyanobacteria from terrestrial and freshwater habitats in the vicinity of arctic ny-alesund, svalbard (790n) (high arctic sea area) was performed in june 2006. species diversity and abundance were evaluated by using epifluorescence microscopy and culturing methods. in total, 29 taxa in 25 genera were identified, of which leptolyngbya spp., trichormus sp. and chlamydomonas nivalis were abundantly present in almost every sample. in several locations, blooms were formed by ... | 2008 | 19195386 |
| an unusual cyanobacterium from saline thermal waters with relatives from unexpected habitats. | cyanobacteria that grow above seawater salinity at temperatures above 45 degrees c have rarely been studied. cyanobacteria of this type of thermo-halophilic extremophile were isolated from siliceous crusts at 40-45 degrees c in a geothermal seawater lagoon in southwest iceland. iceland clone 2e, a leptolyngbya morphotype, was selected for further study. this culture grew only at 45-50 degrees c, in medium ranging from 28 to 94 g l(-1) tds, it showed 3 doublings 24 h(-1) under continuous illumina ... | 2009 | 19543949 |
| cyanotoxins from black band disease of corals and from other coral reef environments. | many cyanobacteria produce cyanotoxins, which has been well documented from freshwater environments but not investigated to the same extent in marine environments. cyanobacteria are an obligate component of the polymicrobial disease of corals known as black band disease (bbd). cyanotoxins were previously shown to be present in field samples of bbd and in a limited number of bbd cyanobacterial cultures. these toxins were suggested as one of the mechanisms contributing to bbd-associated coral tiss ... | 2009 | 19554362 |
| oxygen sensitivity of a nitrogenase-like protochlorophyllide reductase from the cyanobacterium leptolyngbya boryana. | dark-operative protochlorophyllide (pchlide) oxido-reductase (dpor) is a nitrogenase-like enzyme that catalyzes pchlide reduction, the penultimate step of chlorophyll a biosynthesis. dpor is distributed widely among oxygenic phototrophs such as cyanobacteria, green algae and gymnosperms. to determine how dpor operates in oxygenic photosynthetic cells, we constructed two shuttle vectors for overexpression of strep-tagged l-protein (chll) and strep-tagged nb-protein (chln-chlb) in leptolyngbya bor ... | 2009 | 19643808 |
| dinitrogen-fixing cyanobacteria in microbial mats of two shallow coral reef ecosystems. | dinitrogen-fixing organisms in cyanobacterial mats were studied in two shallow coral reef ecosystems: la reunion island, southwestern indian ocean, sesoko (okinawa) island, and northwestern pacific ocean. rapidly expanding benthic miniblooms, frequently dominated by a single cyanobacterial taxon, were identified by microscopy and molecular tools. in addition, nitrogenase activity by these blooms was measured in situ. dinitrogen fixation and its contribution to mat primary production were calcula ... | 2010 | 19705191 |
| optical microscopy in photosynthesis. | emerging as well as the most frequently used optical microscopy techniques are reviewed and image contrast generation methods in a microscope are presented, focusing on the nonlinear contrasts such as harmonic generation and multiphoton excitation fluorescence. nonlinear microscopy presents numerous advantages over linear microscopy techniques including improved deep tissue imaging, optical sectioning, and imaging of live unstained samples. nonetheless, with the exception of multiphoton excitati ... | 2009 | 19851883 |
| global distribution of cyanobacterial ecotypes in the cold biosphere. | perennially cold habitats are diminishing as a result of climate change; however, little is known of the diversity or biogeography of microbes that thrive in such environments. here we use targeted 16s rrna gene surveys to evaluate the global affinities of cold-dwelling cyanobacteria from lake, stream and ice communities living at the northern limit of high arctic canada. pigment signature analysis by hplc confirmed the dominance of cyanobacteria in the phototrophic communities of these high arc ... | 2010 | 19890368 |
| minimal influence of water and nutrient content on the bacterial community composition of a maritime antarctic soil. | bacterial community composition was determined by culture-independent pcr-based methods in two soils differing markedly in their water, c, n and p contents sampled from mars oasis on alexander island, western antarctic peninsula. 16s rrna sequences of the phyla actinobacteria, cyanobacteria, α-proteobacteria and acidobacteria were commonly (> 8% frequency) obtained from soil. those of β-, γ- and δ-proteobacteria, chloroflexi, bacteroidetes, verrucomicrobia, planctomycetes, gemmatimonadetes and f ... | 2010 | 20006478 |
| nitrogen fixation by a marine non-heterocystous cyanobacterium requires a heterotrophic bacterial consort. | cultures of the non-heterocystous cyanobacterium, leptolyngbya nodulosa, could be grown indefinitely in media devoid of combined nitrogen. acetylene reduction assays showed that these cultures fixed nitrogen in the dark period of a diurnal cycle under micro-oxygenic or anaerobic conditions. addition of dcmu to cultures induced much higher rates of nitrogenase activity, most of which occurred in the light. measurements of activity in the presence of chloramphenicol indicated that nitrogenase is s ... | 2010 | 20132280 |
| microcystin production in epiphytic cyanobacteria on submerged macrophytes. | cyanotoxins have been largely studied in planktonic and benthic cyanobacteria, but microcystin (mcyst) production in epiphytic cyanobacteria has not been reported yet. the present study reports for the first time the mcyst production in epiphytic cyanobacteria on submerged macrophytes. during this study, four common submerged macrophytes in eutrophic pond in saudi arabia were surveyed for the presence of toxic epiphytic cyanobacteria. the results showed that chlorophyll-a and total biovolume of ... | 2010 | 20167231 |
| crossbyanols a-d, toxic brominated polyphenyl ethers from the hawai'ian bloom-forming cyanobacterium leptolyngbya crossbyana. | periodically, the marine cyanobacterium leptolyngbya crossbyana forms extensive blooms on hawai'ian coral reefs and results in significant damage to the subtending corals. additionally, corals near mats of this cyanobacterium, but not directly overgrown, have been observed to undergo bleaching. therefore, samples of this cyanobacterium were chemically investigated for bioactive secondary metabolites that might underlie this toxicity phenomenon. (1)h nmr spectroscopy-guided fractionation led to t ... | 2010 | 20170122 |
| nitrate assimilatory genes and their transcriptional regulation in a unicellular red alga cyanidioschyzon merolae: genetic evidence for nitrite reduction by a sulfite reductase-like enzyme. | cyanidioschyzon merolae is a unicellular red alga living in acid hot springs, which is able to grow on ammonium, as well as nitrate as sole nitrogen source. based on the complete genome sequence, proteins for nitrate utilization, nitrate transporter (nrt) and nitrate reductase (nr), were predicted to be encoded by the neighboring nuclear genes cmg018c and cmg019c, respectively, but no typical nitrite reductase (nir) gene was found by similarity searches. on the other hand, two candidate genes fo ... | 2010 | 20375110 |
| bacterial diversity in dry modern freshwater stromatolites from ruidera pools natural park, spain. | ruidera pools natural park, spain, constitutes one of the most representative systems of carbonate precipitation in europe. the prokaryotic community of a dry modern stromatolite recovered from the park has been analyzed by molecular techniques that included denaturing gradient gel electrophoresis (dgge) and 16s rrna gene clone library analysis, together with microscopic observations from the sample and cultures. ribosomal rna was directly extracted to study the putatively active part of the mic ... | 2010 | 20409657 |
| primary screening of the bioactivity of brackishwater cyanobacteria: toxicity of crude extracts to artemia salina larvae and paracentrotus lividus embryos. | cyanobacteria are a diverse group of gram-negative bacteria that produce an array of secondary compounds with selective bioactivity against vertebrates, invertebrates, plants, microalgae, fungi, bacteria, viruses and cell lines. the aim of this study was to assess the toxic effects of aqueous, methanolic and hexane crude extracts of benthic and picoplanktonic cyanobacteria isolated from estuarine environments, towards the nauplii of the brine shrimp artemia salina and embryos of the sea urchin p ... | 2010 | 20411110 |
| characterization of manganese superoxide dismutase from a marine cyanobacterium leptolyngbya valderiana bdu20041. | abstract: | 2010 | 20525290 |
| are known cyanotoxins involved in the toxicity of picoplanktonic and filamentous north atlantic marine cyanobacteria? | 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 assis ... | 2010 | 20631874 |
| methodological constraints in the molecular biodiversity study of a thermomineral spring cyanobacterial mat: a case study. | the biodiversity of a specific cyanobacterial mat associated to a thermomineral spring from the western plain of romania was investigated. light and electron microscopy, together with molecular tools (denaturing gradient gel electrophoresis-dgge, automated ribosomal intergenic spacer analysis-arisa and amplified ribosomal dna restriction analysis-ardra), based on 16s rdna and 16s-23s internal transcribed spacer markers were used. based on the partial 16s rrna fragments sequenced, eight cyanobact ... | 2011 | 20665239 |
| polyphasic characterization of a thermotolerant siderophilic filamentous cyanobacterium that produces intracellular iron deposits. | despite the high potential for oxidative stress stimulated by reduced iron, contemporary iron-depositing hot springs with circum-neutral ph are intensively populated with cyanobacteria. therefore, studies of the physiology, diversity, and phylogeny of cyanobacteria inhabiting iron-depositing hot springs may provide insights into the contribution of cyanobacteria to iron redox cycling in these environments and new mechanisms of oxidative stress mitigation. in this study the morphology, ultrastruc ... | 2010 | 20709851 |
| palmyrolide a, an unusually stabilized neuroactive macrolide from palmyra atoll cyanobacteria. | palmyrolide a (1) is a new neuroactive macrolide isolated from a marine cyanobacterial assemblage composed of leptolyngbya cf. and oscillatoria spp. collected from palmyra atoll. it features a rare n-methyl enamide and an intriguing t-butyl branch; the latter renders the adjacent lactone ester bond resistant to hydrolysis. consistent with its significant suppression of calcium influx in cerebrocortical neurons (ic(50) = 3.70 μm), palmyrolide a (1) showed a relatively potent sodium channel blocki ... | 2010 | 20845912 |
| the pathology of sponge orange band disease affecting the caribbean barrel sponge xestospongia muta. | the aim of this study was to examine sponge orange band (sob) disease affecting the prominent caribbean sponge xestospongia muta. scanning and transmission electron microscopy revealed that sob is accompanied by the massive destruction of the pinacoderm. chlorophyll a content and the main secondary metabolites, tetrahydrofurans, characteristic of x. muta, were significantly lower in bleached than in healthy tissues. denaturing gradient gel electrophoresis using cyanobacteria-specific 16s rrna ge ... | 2010 | 21118276 |
| cytotoxic and antimitotic activities in aqueous extracts of eight cyanobacterial strains isolated from the marine sponge petrosia ficiformis. | marine cyanobacteria are photosynthetic prokaryotes of significant ecological interest, living free or in association with invertebrates. they are also considered as excellent sources of antineoplastic, antibacterial, antiviral and antifungal compounds. in this work, aqueous extracts from eight cyanobacterial strains isolated from the mediterranean sponge petrosia ficiformis have been investigated for their bioactive properties. bioassays with human erythrocytes, artemia salina nauplii, and para ... | 2011 | 21396391 |
| discovery of large conical stromatolites in lake untersee, antarctica. | lake untersee is one of the largest (11.4 km(2)) and deepest (>160 m) freshwater lakes in east antarctica. located at 71°s the lake has a perennial ice cover, a water column that, with the exception of a small anoxic basin in the southwest of the lake, is well mixed, supersaturated with dissolved oxygen, alkaline (ph 10.4) and exceedingly clear. the floor of the lake is covered with photosynthetic microbial mats to depths of at least 100 m. these mats are primarily composed of filamentous cyanop ... | 2011 | 21504538 |
| cyclic depsipeptides, grassypeptolides d and e and ibu-epidemethoxylyngbyastatin 3, from a red sea leptolyngbya cyanobacterium. | two new grassypeptolides and a lyngbyastatin analogue, together with the known dolastatin 12, have been isolated from field collections and laboratory cultures of the marine cyanobacterium leptolyngbya sp. collected from the ss thistlegorm shipwreck in the red sea. the overall stereostructures of grassypeptolides d (1) and e (2) and ibu-epidemethoxylyngbyastatin 3 (3) were determined by a combination of 1d and 2d nmr experiments, ms analysis, marfey's methodology, and hplc-ms. compounds 1 and 2 ... | 2011 | 21806012 |
| physiological characterization and light response of the co(2)-concentrating mechanism in the filamentous cyanobacterium leptolyngbya sp. cpcc 696. | we studied the interactions of the co(2)-concentrating mechanism and variable light in the filamentous cyanobacterium leptolyngbya sp. cpcc 696 acclimated to low light (15-á++mol-ám(-2)-ás(-1) ppfd) and low inorganic carbon (50-á++m-áci). mass spectrometric and polarographic analysis revealed that mediated co(2) uptake along with both active na(+)-independent and na(+)-dependent hco(3) (-) transport, likely through na(+)/hco(3) (-) symport, were employed to concentrate ci internally. combined tr ... | 2011 | 21678048 |
| functional evaluation of a nitrogenase-like protochlorophyllide reductase encoded by the chloroplast dna of physcomitrella patens in the cyanobacterium leptolyngbya boryana. | dark-operative protochlorophyllide (pchlide) oxidoreductase (dpor) is a nitrogenase-like enzyme consisting of the two components, l-protein (a chll dimer) and nb-protein (a chln-chlb heterotetramer), to catalyze pchlide reduction in chl biosynthesis. while nitrogenase is distributed only among certain prokaryotes, the probable structural genes for dpor are encoded by chloroplast dna in lower plants. here we show functional evaluation of dpor encoded by chloroplast dna in a moss physcomitrella pa ... | 2011 | 21949030 |
| Phylogenetic, chemical and morphological diversity of cyanobacteria from Portuguese temperate estuaries. | Cyanobacteria from estuarine habitats have been poorly studied regarding diversity and potential bioactive compounds production compared with their fresh and marine waters' congeners. In this work, 44 cyanobacteria isolates characterised from three Portuguese estuarine environments. Identification was performed based on diacritical morphological features of the isolates (e.g. cell shape, cell size, presence/absence of sheaths) and on 16S rRNA gene sequences phylogenetic analysis. Diversity of pr ... | 2012 | 22093261 |
| microbial biofilms on the sandstone monuments of the angkor wat complex, cambodia. | discoloring biofilms from cambodian temples angkor wat, preah khan, and the bayon and west prasat in angkor thom contained a microbial community dominated by coccoid cyanobacteria. molecular analysis identified chroococcidiopsis as major colonizer, but low similarity values (<95%) suggested a similar genus or species not present in the databases. in only two of the six sites sampled were filamentous cyanobacteria, microcoleus, leptolyngbya, and scytonema, found; the first two detected by sequenc ... | 2011 | 22006074 |
| Acute necrotizing enterocolitis of preterm piglets is characterized by dysbiosis of ileal mucosa-associated bacteria. | Investigation of bacteria involved in pathogenesis of necrotizing enterocolitis (NEC) is limited by infant fragility, analysis restricted to feces, use of culture-based methods, and lack of clinically-relevant animal models. This study used a unique preterm piglet model to characterize spontaneous differences in microbiome composition of NEC-predisposed regions of gut. Preterm piglets (n=23) were cesarean-delivered and nurtured for 30 hours over which time 52% developed NEC. Bacterial DNA from ... | 2011 | 21983069 |
| comparative analysis of cyanobacteria in the rhizosphere and as endosymbionts of cycads in drought-effected soils. | does the diversity of cyanobacteria in the cycad rhizosphere relate to the cyanobiont species found in the coralloid roots of these ancient plants? the aim of this study was to identify the diversity of soil cyanobacteria occurring in the immediate vicinity of 22 colonised coralloid roots belonging to members of the cycad genera: macrozamia, lepidozamia, bowenia and cycas. the majority of coralloid roots were sampled at depths greater than 10 cm below the soil surface. a total of 32 cyanobacteri ... | 2012 | 22224502 |