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diversity of the fatty acids of the nostoc species and their statistical analysis.low molecular, hydroxy, dioic, saturated and unsaturated fatty acids were determined of six cyanobacterial species belonging to genus nostoc and in different habitats: freshwater, terrestrial, and as well as symbionts. there are large variations in individual fatty acid contents according to species, and location of the genus nostoc. statistical analysis of variability of fatty acids belonging to the genus nostoc is reported.200716563711
ftsz may have dual roles in the filamentous cyanobacterium nostoc/anabaena sp. strain pcc 7120.the cellular and subcellular localization of ftsz, a bacterial cell division protein, were investigated in vegetative cells of the filamentous cyanobacterium nostoc/anabaena sp. strain pcc 7120. we show by using immunogold-transmission electron microscopy that ftsz forms a ring structure in a filamentous cyanobacterium, similar to observations in unicellular bacteria and chloroplasts. this finding, that the ftsz in a filamentous cyanobacterium accumulates at the growing edge of the division sept ...200716603273
poly-beta-hydroxybutyrate accumulation in nostoc muscorum: effects of metabolic inhibitors.poly-beta-hydroxybutyrate (phb) accumulation in nostoc muscorum was studied in presence of various metabolic inhibitors. supplementation of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu) was found to suppress phb accumulation in phosphate-limited n. muscorum under photoautotrophic growth condition. phb accumulation increased up to 21% and 17% from an initial phb content of 8.5% of dry weight, respectively, under carbonylcyanide m-chlorophenylhydrazone (cccp) and dicyclohexylcarbodiimide (dccd) t ...200716542751
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 ...200819295090
growth and periodicity of cyanobacterial bloom in a polluted pond of agra city.periodical changes in physico-chemical properties and cyanophycean bloom in a pond ofagra city during the year 2005 and 2006 were studied. it was recorded that the pond water was polluted throughout the study period and this was closely associated with cyanobacterial bloom. during summer (march to june), the pond water was highly polluted, as it was rich in various nutrients and phosphates in particular. the ph of pond water was high with low do and this was associated with the highest peak of w ...200819297980
repression of proinflammatory gene expression by lipid extract of nostoc commune var sphaeroides kützing, a blue-green alga, via inhibition of nuclear factor-kappab in raw 264.7 macrophages.we investigated whether lipid extract from a blue-green alga, n commune, modulates proinflammatory gene expression in raw 264.7 macrophages. the cells were incubated with n commune lipid extract (0-100 microg/ml) and subsequently activated by lps (100 ng/ml). quantitative real-time pcr analysis showed that mrna abundance of proinflammatory mediators, including tnf-alpha, cox-2, il-1beta, il-6, and inos, was significantly reduced by n commune lipid extract in a dose-dependent manner. secretion of ...200819083393
only plant-type (glyk) glycerate kinases produce d-glycerate 3-phosphate.d-glycerate kinases (gk) occur in three phylogenetically distinct classes. class ii gks produce glycerate 2-phosphate, while both class i gk and class iii gk (glyk) are thought to produce glycerate 3-phosphate. we report on the identification of a bacterial-type class i gk in the unicellular cyanobacterium synechocystis sp. strain pcc 6803 and of a plant-type glyk in the filamentous cyanobacterium nostoc sp. strain pcc 7120. the comparison with other prokaryotic and eukaryotic gks of both classe ...200818675808
morphological variability in selected heterocystous cyanobacterial strains as a response to varied temperature, light intensity and medium composition.the effect of temperature, light and nutrient composition on morphological traits was determined in seven nostocacean cyanobacteria (anabaena planctonica, a. sphaerica var. conoidea, a. spiroides, aphanizomenon gracile, nostoc sp., scytonema sp., and tolypothrix sp.). their morphological variability was high but only some of the features showed changes reflecting varied growth conditions. the frequency of heterocyst occurrence decreased with increasing nitrogen concentration. within the range st ...200818759118
dna microarray comparisons of plant factor- and nitrogen deprivation-induced hormogonia reveal decision-making transcriptional regulation patterns in nostoc punctiforme.hormogonia are nongrowing filaments, motile by means of a gliding mechanism, that are produced by certain cyanobacteria. their differentiation is induced by positive and negative factors for growth, such as deprivation of combined nitrogen (nitrogen stress induction [nsi]). in nostoc punctiforme, they are also induced by the exudate (hormogonium-inducing factor [hif]) of a symbiotic plant partner. time course (0.5 to 24 h) transcription profiles were determined by dna microarray assays for hormo ...200818790872
[purification and characterization of extracellular polysaccharides from nostoc flagelliforme].the extracellular polysaccharides (eps) of n. flagelliforme were purified by deae anion exchange chromatography and sephadex g100 gel filtration chromatography. and two main components named nfps1 and nfps2 were obtained respectively. the physico-chemical characteristics of nfps2 were analyzed and compared with nfps0, which was obtained from field colony of n. flagelliforme. these results showed that both of nfps2 and nfpso were composed of four monosaccharides: glucose, xylose, galactose and ma ...200818807987
characterization of cyanobacterial carotenoid ketolase crtw and hydroxylase crtr by complementation analysis in escherichia coli.the pathway from beta-carotene to astaxanthin is a crucial step in the synthesis of astaxanthin, a red antioxidative ketocarotenoid that confers beneficial effects on human health. two enzymes, a beta-carotene ketolase (carotenoid 4,4'-oxygenase) and a beta-carotene hydroxylase (carotenoid 3,3'-hydroxylase), are involved in this pathway. cyanobacteria are known to utilize the carotenoid ketolase crtw and/or crto, and the carotenoid hydroxylase crtr. here, we compared the catalytic functions of c ...200818987067
antibacterial, antifungal and cytotoxic activity of terrestrial cyanobacterial strains from serbia.cyanobacteria are known to be a rich source of biologically active compounds some of which can have pharmaceutical importance. in this work we present the screening results of cyanobacterial strains for their antibacterial, antifungal, and cytotoxic activity. cyanobacterial strains were isolated from various soil types in province of vojvodina and central serbia, republic of serbia. the screening included 9 strains of anabaena and 9 strains of nostoc. both, extracellular products (from the cultu ...200818815758
nbla, a key protein of phycobilisome degradation, interacts with clpc, a hsp100 chaperone partner of a cyanobacterial clp protease.when cyanobacteria are starved for nitrogen, expression of the nbla protein increases and thereby induces proteolytic degradation of phycobilisomes, light-harvesting complexes of pigmented proteins. phycobilisome degradation leads to a color change of the cells from blue-green to yellow-green, referred to as bleaching or chlorosis. as reported previously, nbla binds via a conserved region at its c terminus to the alpha-subunits of phycobiliproteins, the main components of phycobilisomes. we demo ...200818818204
new peptolides from the cyanobacterium nostoc insulare as selective and potent inhibitors of human leukocyte elastase.eight new cyanopeptolins (insulapeptolides a-h) were obtained from the cyanobacterium nostoc insulare. their isolation was guided by their bioactivity toward the target enzyme human leukocyte elastase, molecular biological investigations, and maldi-tof analysis. these peptides are selective inhibitors of human leukocyte elastase with activities in the nanomolar range. insulapeptolide d was the most potent compound with an ic(50) value of 85 nm (k(i) value of 36 nm).200818924217
differential sensitivity of five cyanobacterial strains to ammonium toxicity and its inhibitory mechanism on the photosynthesis of rice-field cyanobacterium ge-xian-mi (nostoc).effects of two fertilizers, nh(4)cl and kcl, on the growth of the edible cyanobacterium ge-xian-mi (nostoc) and four other cyanobacterial strains were compared at ph 8.3+/-0.2 and 25 degrees c. their growth was decreased by at least 65% at 10 mmol l(-1) nh(4)cl but no inhibitory effect was observed at the same level of kcl. meanwhile, the strains exhibited a great variation of sensitivity to nh(4)(+) toxicity in the order: ge-xian-mi>anabaena azotica fachb 118>microcystis aeruginosa fachb 905>m. ...200818640729
nitrogen fixation by phyllosphere bacteria associated with higher plants and their colonizing epiphytes of a tropical lowland rainforest of costa rica.leaf surfaces (phyllospheres) have been shown to provide appropriate conditions for colonization by microorganisms including diazotrophic bacteria that are able to fix atmospheric nitrogen (n(2)). in this study, we determined leaf-associated n(2) fixation of a range of rainforest plants in costa rica, under different environmental conditions, by tracing biomass n incorporation from (15)n(2). n(2)-fixing bacterial communities of the plant species carludovica drudei, grias cauliflora and costus la ...200818273066
novel thermostable glycosidases in the extracellular matrix of the terrestrial cyanobacterium nostoc commune.the cyanobacterium nostoc commune is adapted to the terrestrial environment and forms a visible colony in which the cells are embedded in extracellular polysaccharides (epss), which play a crucial role in the extreme desiccation tolerance of this organism. when natural colonies were immersed in water, degradation of the colonies occurred within 2 days and n. commune cells were released into the water. the activities that hydrolyze glycoside bonds in various n. commune fractions were examined usi ...200819029765
widespread distribution and identification of eight novel microcystins in antarctic cyanobacterial mats.the microcystin (mc) content and cyanobacterial community structure of antarctic microbial mat samples collected from 40 ponds, lakes, and hydroterrestrial environments were investigated. samples were collected from bratina island and four of the dry valleys, wright, victoria, miers, and marshall. enzyme-linked immunosorbent assays (elisas), liquid chromatography-mass spectrometry (lc-ms), and protein phosphatase 2a (pp-2a) inhibition assays resulted in the identification of low levels (1 to 16 ...200818849457
isolation and characterization of the gene associated with geosmin production in cyanobacteria.geosmin is a secondary metabolite responsible for earthy tastes and odors in potable water supplies. geosmin continues to be a challenge to water utility management regimes and remains one of the most common causes of consumer complaints, as the taste of "dirty" water may suggest a failed disinfection regime and that the water may be unsafe to drink. although cyanobacteria have been reported to be largely responsible for these taste and odor events, the answer as to how or why geosmin is produce ...200819031897
the involvement of the antioxidant system in protection of desert cyanobacterium nostoc sp. against uv-b radiation and the effects of exogenous antioxidants.in this study, we found that uv-b radiation decreased photosynthetic activity and boosted lipid peroxidation of desert nostoc sp., and exogenous chemicals (ascorbate acid (asc), n-acetylcysteine (nac), and sodium nitroprusside (snp)) had obvious protective effects on photosynthesis and membranes under uv-b radiation. high-concentration snp boosted the activities of antioxidant enzymes, but low-concentration snp reduced the activities of antioxidant enzymes. both nac and asc treatments of cells d ...200816759702
mutation at different sites in the nostoc punctiforme cyac gene, encoding the multiple-domain enzyme adenylate cyclase, results in different levels of infection of the host plant blasia pusilla.the filamentous cyanobacterium nostoc punctiforme forms symbioses with plants. disruption of the catalytic domain of the n. punctiforme adenylate cyclase (cyac) significantly increased symbiotic competence, whereas reduced infectivity was observed in a mutant with a disruption close to the n terminus of cyac. the total cellular cyclic amp levels were significantly reduced in both mutants.200818156269
yest: a new rhamnogalacturonan acetyl esterase from bacillus subtilis.yest, a putative protein from bacillus subtilis atcc 6633 that has been provisionally classified as a rhamnogalacturonan acetyl esterase (rgae) in ce-12 family, was cloned, expressed in escherichiacoli rosetta (de3), and purified. the enzyme is monomeric with a molecular mass of 37 kda and presents thermophilic properties similar to rgae from aspergillus aculeatus, although yest is more alkaliphilic. the study of inhibitors confirmed the importance of the his and the nucleophilic ser for the est ...200817957779
allergenicity of airborne cyanobacteria phormidium fragile and nostoc muscorum.in recent times, airborne microorganisms and their constituents have become prominent safety and health concern. ongoing climatic changes coupled with unwarranted human activities have significantly deteriorated the ambient air quality. in certain environments, airborne algae contribute significantly to the total biological load of the atmosphere, hitherto dominated by bacteria and fungi. present study was aimed to investigate the allergenic potency of two frequent viable algal forms i.e., phorm ...200817011621
screening of microalgae for species excreting norharmane, a manifold biologically active indole alkaloid.a screening of microalgae strains is described, with the objective to discover more species besides the known cyanobacterium nodularia harveyana which excrete the manifold biologically active and co-mutagenic indole alkaloid norharmane (9h-pyrido(3,4-b)indole) into their environment. seven more cyanobacterial species, anabaena cylindrica, anabaena inaequalis, anabaenopsis siamensis, chroococcus minutus, nostoc carneum, nostoc commune and phormidium foveolarum, were newly discovered. the norharma ...200816872816
[studies on evaluation of natural products for antiviral effects and their applications].in the search for novel antiviral molecules from natural products, we have discovered various antiviral molecules with characteristic mechanisms of action. scopadulciol (sdc), isolated from the tropical medicinal plant scoparia dulcis l., showed stimulatory effects on the antiviral potency of acyclovir (acv) or ganciclovir (gcv). this effect of sdc was exerted via the activation of viral thymidine kinase (hsv-1 tk) and, as a result, an increase in the cellular concentration of the active form of ...200818176057
identification of hepatotoxin-producing cyanobacteria by dna-chip.we developed a new tool to detect and identify hepatotoxin-producing cyanobacteria of the genera anabaena, microcystis, planktothrix, nostoc and nodularia. genus-specific probe pairs were designed for the detection of the microcystin (mcye) and nodularin synthetase genes (ndaf) of these five genera to be used with a dna-chip. the method couples a ligation detection reaction, in which the polymerase chain reaction (pcr)-amplified mcye/ndaf genes are recognized by the probe pairs, with a hybridiza ...200818190512
treatment of influenza a (h1n1) virus infections in mice and ferrets with cyanovirin-n.cyanovirin-n (cv-n), a protein derived from nostoc ellipsosporum, neutralizes influenza virus infectivity by binding to specific high-mannose oligosaccharides (oligomannose-8 and -9) at glycosylation sites on the viral hemagglutinin ha1 subunit. mouse-adapted viruses lose sensitivity to cv-n due to ha1 mutations that eliminate these glycosylation sites. recently we created a hybrid (reassortant) influenza a/wsn/33 (h1n1) virus containing the ha gene of a/new caledonia/20/99 (h1n1) with an asp225 ...200818601954
genes of cyanobacterial origin in plant nuclear genomes point to a heterocyst-forming plastid ancestor.plastids are descended from a cyanobacterial symbiosis which occurred over 1.2 billion years ago. during the course of endosymbiosis, most genes were lost from the cyanobacterium's genome and many were relocated to the host nucleus through endosymbiotic gene transfer (egt). the issue of how many genes were acquired through egt in different plant lineages is unresolved. here, we report the genome-wide frequency of gene acquisitions from cyanobacteria in 4 photosynthetic eukaryotes--arabidopsis, r ...200818222943
potent and selective antiplasmodial activity of the cyanobacterial alkaloid nostocarboline and its dimers.the quaternary beta-carbolinium alkaloid nostocarboline from the cyanobacterium nostoc 78-12a and 10 bis-cationic dimeric derivatives were evaluated against four protozoan parasites and low micromolar values against trypanosoma brucei, submicromolar values against leishmania donovani and low nanomolar values against plasmodium falciparum k1 were determined. selectivity against rat myoblasts (l6 cells) was found to be up to >2500-fold.200818606541
identification of sesquiterpene synthases from nostoc punctiforme pcc 73102 and nostoc sp. strain pcc 7120.cyanobacteria are a rich source of natural products and are known to produce terpenoids. these bacteria are the major source of the musty-smelling terpenes geosmin and 2-methylisoborneol, which are found in many natural water supplies; however, no terpene synthases have been characterized from these organisms to date. here, we describe the characterization of three sesquiterpene synthases identified in nostoc sp. strain pcc 7120 (terpene synthase ns1) and nostoc punctiforme pcc 73102 (terpene sy ...200818658271
growth kinetics of 1-2 mm and 3-4 mm colonies of nostoc sphaeroides (cyanophyta) in outdoor culture.nostoc sphaeroides kützing was cultivated in paddlewheel-driven raceway ponds and the growth kinetics of 1-2 mm and 3-4 mm colonies of n. sphaeroides was studied. the biomass productivities in 2.5 m(2) raceway ponds inoculated with 1-2 mm and 3-4 mm colonies were 5.2 and 0.25 g dry wt m(-2) d(-1), respectively. furthermore, differently sized colonies showed different relative water content, total soluble carbohydrates, chlorophyll a content and density of filaments. this is the first report on m ...200818661109
genetic diversity among and within cultured cyanobionts of diverse species of azolla.the cyanobionts isolated from 10 azolla accessions belonging to 6 species (azolla mexicana, a. microphylla, a. rubra, a. caroliniana, a. filiculoides, a. pinnata) were cultured under laboratory conditions and analyzed on the basis of whole cell protein profiles and molecular marker dataset generated using repeat sequence primers (strr(mod) and hiptg). the biochemical and molecular marker profiles of the cyanobionts were compared with those of the free-living cyanobacteria and symbiotic nostoc st ...200818481216
in vitro characterization of a carotenoid cleavage dioxygenase from nostoc sp. pcc 7120 reveals a novel cleavage pattern, cytosolic localization and induction by highlight.carotenoid oxygenases catalyse the cleavage of c-c double bonds forming apocarotenoids, a diverse group of compounds, including retinoids and the precursors of some phytohormones. some apocarotenoids, like beta-ionone (c(13)), are ecologically important volatiles released by plants and cyanobacteria. in this work, we elucidated the activity of the nostoccarotenoid cleavage dioxygenase (nosccd, previously named nsc1) using synthetic and cyanobacterial substrates. nosccd converted bicyclic and mon ...200818485074
mutation of a gene for thyroid transcription factor-1 (titf1) in a patient with clinical features of resistance to thyrotropin.resistance to tsh (rtsh [mim 275200]) is a heterogeneous condition defined by variable degree of insensitivity to biologically active tsh. while this condition is classically caused by loss-of-function mutations of the tsh receptor gene (tshr), several patients have exhibited rtsh-like phenotype in the apparent absence of tshr mutations, and some of them have mutations of pax8 or gnas1. we identified a japanese boy with congenital hypothyroidism who suffered from recurrent lower respiratory infe ...200818506088
[cyanobacterium nostoc paludosum kütz as a basis of creation of agriculturally useful microbial associations by the example of bacteria of the genus rhizobium].different species of rhizobium were successfully introduced into the extracellular slime of nostoc paludosum (kütz) elenk, strain 18; cyanobacteria did not eliminate them and exhibited no specificity to the introduced species. both partners were shown to exist in a self-sufficient manner in an artificial consortium, the stability of which is determined by the technology of growing the cultures in collections. cyanobacteria act as carriers of introduced satellites, providing contact with the inoc ...200818522330
a novel photoactive gaf domain of cyanobacteriochrome anpixj that shows reversible green/red photoconversion.we report the discovery of a novel cyanobacteriochrome, the green/red photoreceptor anpixj (all1069), isolated from the heterocyst-forming cyanobacterium anabaena (nostoc) sp. pcc 7120. cyanobacteriochromes are a recently emerging tetrapyrrole-based photoreceptor superfamily that are distantly related to the conventional red/far-red photoreceptor phytochromes (phys). the chromophore-binding domains of anpixj produced in cyanobacterial and escherichia coli cells both showed a reversible and full ...200818571200
endosulfan induced biochemical changes in nitrogen-fixing cyanobacteria.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 ...200818584851
very small mobile repeated elements in cyanobacterial genomes.mobile dna elements play a major role in genome plasticity and other evolutionary processes, an insight gained primarily through the study of transposons and retrotransposons (generally approximately 1000 nt or longer). these elements spawn smaller parasitic versions (generally >100 nt) that propagate through proteins encoded by the full elements. highly repeated sequences smaller than 100 nt have been described, but they are either nonmobile or their origins are not known. we have surveyed the ...200818599681
sequestration of chromium by exopolysaccharides of nostoc and gloeocapsa from dilute aqueous solutions.this article reports the chromium removal potential of exopolysaccharides (eps) of two indigenously isolated cyanobacterial strains, gloeocapsa calcarea and nostoc punctiforme. the biosorption was studied by varying ph from 2 to 6 and initial chromium concentration from 5 to 20mg/l to find out the optimized conditions for maximum chromium removal by eps. two equilibrium models, langmuir and freundlich, were used to explain these results. the freundlich model was found to be better applicable to ...200818280649
mechanisms to avoid photoinhibition in a desiccation-tolerant cyanobacterium, nostoc commune.a desiccation-tolerant cyanobacterium, nostoc commune, shows unique responses to dehydration. these responses are: (i) loss of psii activity in parallel with the loss of photosynthesis; (ii) loss of psi activity; and (iii) dissipation of light energy absorbed by pigment-protein complexes. in this study, the deactivation of psii is shown to be important in avoiding photoinhibition when the calvin-benson cycle is repressed by dehydration. furthermore, our evidence suggests that dissipation of ligh ...200818252733
a common transport system for methionine, l-methionine-dl-sulfoximine (msx), and phosphinothricin (ppt) in the diazotrophic cyanobacterium nostoc muscorum.we present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues l-methionine-dl-sulfoximine (msx) and phosphinothricin (ppt) in cyanobacterium nostoc muscorum. methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. the cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, l ...200818266032
cyanobacteria-bryophyte symbioses.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 ...200818267939
substrate specificities and availability of fucosyltransferase and beta-carotene hydroxylase for myxol 2'-fucoside synthesis in anabaena sp. strain pcc 7120 compared with synechocystis sp. strain pcc 6803.to elucidate the biosynthetic pathways of carotenoids, especially myxol 2'-glycosides, in cyanobacteria, anabaena sp. strain pcc 7120 (also known as nostoc sp. strain pcc 7120) and synechocystis sp. strain pcc 6803 deletion mutants lacking selected proposed carotenoid biosynthesis enzymes and gdp-fucose synthase (wcag), which is required for myxol 2'-fucoside production, were analyzed. the carotenoids in these mutants were identified using high-performance liquid chromatography, field desorption ...200818708496
effect of exogenous extracellular polysaccharides on the desiccation and freezing tolerance of rock-inhabiting phototrophic microorganisms.two major stresses that threaten rock-inhabiting microbial communities are desiccation and freezing; both result in a loss of liquid water in the cells. the mechanisms necessary to tolerate these extremes may be similar, but are not well understood. in both cases extracellular polysaccharides (eps) seem to play an important role. this study examines whether the eps released by a rock-inhabiting phototroph can have a protective effect on other members of similar and neighboring microbial communit ...200818710394
withdrawal. 'genetically modified cyanobacterium nostoc muscorum overproducing proline in response to salinity and osmotic stresses' by santosh bhargava (journal of biosciences, volume 31, no. 2, pages 265-272, june 2006). 200818754157
excision of the nifd element in the heterocystous cyanobacteria.heterocyst differentiation in cyanobacteria is accompanied by developmentally regulated dna rearrangements that occur within the nifd, fdxn, and hupl genes. these genetic elements are excised from the genome by site-specific recombination during the latter stages of differentiation. the nifd element is excised by the recombinase, xisa, located within the element. our objective was to examine the xisa-mediated excision of the nifd element. to accomplish this, we observed the ability of xisa to ex ...200818283436
lipid extract of nostoc commune var. sphaeroides kutzing, a blue-green alga, inhibits the activation of sterol regulatory element binding proteins in hepg2 cells.nostoc commune var. sphaeroides kützing (n. commune), a blue-green alga, has been used as both a food ingredient and in medicine for centuries. to determine the effect of n. commune on cholesterol metabolism, n. commune lipid extract was incubated at increasing concentrations (25-100 mg/l) with hepg2 cells, a human hepatoma cell line. the addition of n. commune lipid extract markedly reduced mrna abundance of 3-hydroxy-3-methylglutaryl-coa reductase (hmgr) and ldl receptor (ldlr) (p < 0.05), wit ...200818287352
5s rrna-recognition module of ctc family proteins and its evolution.the effects of amino acid replacements in the rna-binding sites of homologous ribosomal proteins tl5 and l25 (members of the ctc family) on ability of these proteins to form stable complexes with ribosomal 5s rna were studied. it was shown that even three simultaneous replacements of non-conserved amino acid residues by alanine in the rna-binding site of tl5 did not result in noticeable decrease in stability of the tl5-5s rrna complex. however, any replacement among five conserved residues in th ...200818298371
biosorption of lead(ii) from aqueous solutions by non-living algal biomass oedogonium sp. and nostoc sp.--a comparative study.industrial wastewaters containing heavy metals pose a major environmental problem that needs to be remedied. the present study reports the ability of two non-living (dried) fresh water algae, oedogonium sp. and nostoc sp. to remove lead(ii) from aqueous solutions in batch system under varying range of ph (2.99-7.04), contact time (5-300 min), biosorbent dose (0.1-0.8 g/l), and initial metal ion concentrations (100 and 200mg/l). the optimum conditions for lead biosorption are almost same for the ...200818321684
aerophytic cyanophyceae (cyanobacteria) from some cairo districts, egypt.twenty three aerophytic blue-green algal species were isolated and identified from 5 districts in cairo, namely: nasr city, abassiya, downtown, maadi and tebbin. downtown contained the highest numbers of total algal species (13 species) during the study throughout the years 2004-2005 in comparison to other districts. the composition of aeroalgal taxa varied with seasonal changes. chroococcus limenticus, lyngbya lagerheimii, phormidium ambigum and schizothrix purpurascens have been isolated durin ...200818817259
genetic diversity in cyanobacterial symbionts of thalloid bryophytes.two species of thalloid liverworts, blasia pusilla and cavicularia densa, form stable symbioses with nitrogen-fixing cyanobacteria. both bryophytes promote the persistence of their cyanobacterial associations by producing specialized gemmae, which facilitate the simultaneous dispersal of the host and its nitrogen-fixing symbionts. here the genetic diversity of cyanobacterial symbionts of blasia and cavicularia is examined. the results indicate that the primary symbionts of both bryophytes are cl ...200818325923
chromium (vi) tolerance in two halotolerant strains of nostoc.the present study reports on chromium (vi) tolerance of two cyanobacterial strains nostoc linckia and nostoc spongiaeforme isolated from salt affected soils using uni-algal and bi-algal systems. besides distinct halophilism, the two strains exhibited remarkable tolerance to chromium (vi) and revealed 1.2 to 2.8 times more chlorophyll in the presence of the metal. while phycobilins and carotenoids also increased in nostoc linckia with total dissolved salts (tds) as well as metal, a decline was ob ...200818831365
analysis of the cryptophycin p450 epoxidase reveals substrate tolerance and cooperativity.cryptophycins are potent anticancer agents isolated from nostoc sp. atcc 53789 and nostoc sp. gsv 224. the most potent natural cryptophycin analogues retain a beta-epoxide at the c2'-c3' position of the molecule. a p450 epoxidase encoded by c rpe recently identified from the cryptophycin gene cluster was shown to install this key functional group into cryptophycin-4 (cr-4) to produce cryptophycin-2 (cr-2) in a regio- and stereospecific manner. here we report a detailed characterization of the cr ...200818366166
properties of a mini 9r-lipoxygenase from nostoc sp. pcc 7120 and its mutant forms.lipoxygenases (loxs) consist of a class of enzymes that catalyze the regio- and stereospecific dioxygenation of polyunsaturated fatty acids. current reports propose that a conserved glycine residue in the active site of r-lipoxygenases and an alanine residue at the corresponding position in s-lipoxygenases play a crucial role in determining the stereochemistry of the product. recently, a bifunctional lipoxygenase with a linoleate diol synthase activity from nostoc sp. pcc7120 with r stereospecif ...200818439634
transcription of the extended hyp-operon in nostoc sp. strain pcc 7120.the maturation of hydrogenases into active enzymes is a complex process and e.g. a correctly assembled active site requires the involvement of at least seven proteins, encoded by hypabcdef and a hydrogenase specific protease, encoded either by hupw or hoxw. the n2-fixing cyanobacterium nostoc sp. strain pcc 7120 may contain both an uptake and a bidirectional hydrogenase. the present study addresses the presence and expression of hyp-genes in nostoc sp. strain pcc 7120.200818442387
quantitative shotgun proteomics of enriched heterocysts from nostoc sp. pcc 7120 using 8-plex isobaric peptide tags.the filamentous cyanobacterium nostoc sp. strain pcc 7120 is capable of fixing atmospheric nitrogen. the labile nature of the core process requires the terminal differentiation of vegetative cells to form heterocysts, specialized cells with altered cellular and metabolic infrastructure to mediate the n2-fixing process. we present an investigation targeting the cellular proteomic expression of the heterocysts compared to vegetative cells of a population cultured under n2-fixing conditions. new 8- ...200818290607
a lipoxygenase with linoleate diol synthase activity from nostoc sp. pcc 7120.the dioxygenation of pufas (polyunsaturated fatty acids) in plants is mainly catalysed by members of the lox (lipoxygenase) enzyme family. lox products may be further metabolized, and are known as signalling substances in plant development and in responses to wounding and pathogen attack. in contrast with the situation in eukaryotes, information on the relevance of lipid peroxide metabolism in prokaryotic organisms is scarce. therefore, we aimed to analyse loxs and oxylipin patterns of cyanobact ...200818031288
differential patterns of evolution and distribution of the symbiotic behaviour in nostocacean cyanobacteria.many cyanobacteria commonly identified as belonging to the genus nostoc are well-known cyanobionts (symbionts) of a wide variety of plants and fungi. they form symbioses with bryophytes, pteridophytes, gymnosperms and angiosperms that are considerably different in the type of reciprocal interaction between the host and the cyanobiont. the phylogenetic and taxonomic relationships among cyanobionts isolated from different hosts and nostoc strains isolated from free-living conditions are still not ...200818319454
nezha, a novel active miniature inverted-repeat transposable element in cyanobacteria.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 sec ...200818035045
cyanobacteria (nostoc commune) used as a dietary item in the peruvian highlands produce the neurotoxic amino acid bmaa.in the mountains of peru, globular colonies of nostoc commune (nostocales) are collected in the highland lakes by the indigenous people, who call them llullucha. they are consumed locally, traded for maize, or sold, eventually entering the folk markets of cusco and other neighboring cities. throughout highland peru, nostoc commune is highly salient as a seasonal dietary item, being eaten alone, or in picante -- a local stew -- and is said to be highly nutritious. nostoc commune has been known to ...200818495396
sorption and desorption studies of chromium(vi) from nonviable cyanobacterium nostoc muscorum biomass.this communication presents results pertaining to the sorptive and desorptive studies carried out on chromium(vi) removal onto nonviable freshwater cyanobacterium (nostoc muscorum) biomass. influence of varying the conditions for removal of chromium(vi), such as the ph of aqueous solution, the dosage of biosorbent, the contact time with the biosorbent, the temperature for the removal of chromium, the effect of light metal ions and the adsorption-desorption studies were investigated. sorption int ...200818053641
crystal structure of the glur0 ligand-binding core from nostoc punctiforme in complex with l-glutamate: structural dissection of the ligand interaction and subunit interface.glur0 from nostoc punctiforme (npglur0) is a bacterial homologue of the ionotropic glutamate receptor (iglur). we have solved the crystal structure of the ligand-binding core of npglur0 in complex with l-glutamate at a resolution of 2.1 a. the structure exhibits a noncanonical ligand interaction and two distinct subunit interfaces. the side-chain guanidium group of arg80 forms a salt bridge with the gamma-carboxyl group of bound l-glutamate: in glur0 from synechocystis (sglur0) and other iglurs, ...200818164033
[structure and antiviral activity of an acidic polysaccharide from an edible blue-green alga, nostoc flagelliforme].recently, the development of antiviral agents with novel mechanisms of action has been required since many types of infectious disease have become a serious problem in our society. in the present study, we isolated a novel acidic polysaccharide, nostoflan (nsf), from a terrestrial blue-green alga, nostoc flagelliforme, and examined its structure and antiviral activity. the sugar composition and methylation analyses of nsf revealed that it is mainly composed of (-->4)- d-glcp-(1-->, -->6,4)-d-glc ...200818451619
pas-mediated dimerization of soluble guanylyl cyclase revealed by signal transduction histidine kinase domain crystal structure.signal transduction histidine kinases (sthk) are key for sensing environmental stresses, crucial for cell survival, and attain their sensing ability using small molecule binding domains. the n-terminal domain in an sthk from nostoc punctiforme is of unknown function yet is homologous to the central region in soluble guanylyl cyclase (sgc), the main receptor for nitric oxide (no). this domain is termed h-noxa (or h-noba) because it is often associated with the heme-nitric oxide/oxygen binding (h- ...200818006497
selectivity in the heavy metal removal by exopolysaccharide-producing cyanobacteria.the aim of this study was to assess the selective removal of cu(ii), cr(iii) and ni(ii) by strains of exopolysaccharide (eps)-producing cyanobacteria, and to investigate the interaction of sorption in solutions with multiple-metals.200818248368
quorum quenching activity in anabaena sp. pcc 7120: identification of aiic, a novel ahl-acylase.many bacteria use quorum sensing (qs) to coordinate responses to environmental changes. in gram-negative bacteria, the most extensively studied qs systems rely on the use of n-acylhomoserine lactones (ahls) signal molecules. some bacteria produce enzymes that are able to inactivate ahl signals produced by other bacteria and hence interfere with qs-mediated processes via a phenomenon known as quorum quenching. acylase-type ahl degradation activity has been found in the biomass of the filamentous ...200818194337
effects of nitrogen source on the synthesis of the uv-screening compound, scytonemin, in the cyanobacterium nostoc punctiforme pcc 73102.the effects of nitrogen source (n(2), no(3)(-) and nh(4)(+)) on scytonemin synthesis were investigated in the heterocystous cyanobacterium nostoc punctiforme pcc 73102. with the required uva radiation included, nostoc synthesized three to seven times more scytonemin while fixing nitrogen than when utilizing nitrate or ammonium. a similar increase in scytonemin synthesis occurred when nitrate or ammonium became depleted by growth and nostoc switched to diazotrophic metabolism with the differentia ...200818218026
the odd behaviour of carbonic anhydrase in the terrestrial cyanobacterium nostoc flagelliforme during hydration-dehydration cycles.the terrestrial cyanobacterium nostoc flagelliforme, inhabiting arid areas, withstands prolonged periods of dehydration. how dehydration and occasional wetting affect inorganic c acquisition in this organism is not well known. as inorganic c acquisition in cyanobacteria often involves carbonic anhydrases (ca), we studied the effect of cycles of hydration and dehydration on the extracellular and intracellular ca activities, at the ph values presumably associated with dew or rain wetting. the exte ...200818177372
screening for acetylcholinesterase inhibitory activity in cyanobacteria of the genus nostoc.fifty-four cyanobacterial strains of the genus nostoc from different habitats were screened for acetylcholinesterase inhibitory activity. water-methanolic extracts from freeze-dried biomasses were tested for inhibitory activity using ellman's spectrophotometric method. acetylcholinesterase inhibitory activity higher than 90% was found in the crude extracts of nostoc sp. str. lukesova 27/97 and nostoc ellipsosporum rabenh. str. lukesova 51/91. extracts from nostoc ellipsosporum str. lukesova 52/9 ...200918951237
crystal structure of npun_r1517, a putative negative regulator of heterocyst differentiation from nostoc punctiforme pcc 73102. 200919089958
an evaluation of four phylogenetic markers in nostoc: implications for cyanobacterial phylogenetic studies at the intrageneric level.the success of some phylogenetic markers in cyanobacteria owes to the design of cyanobacteria-specific primers, but a few studies have directly investigated the evolution "behavior" of the loci. in this study, we performed a case study in nostoc to evaluate rpoc1, hetr, rbclx, and 16s rrna-trna(ile)-trna(ala)-23s rrna internal transcribed spacer (its) as phylogenetic markers. the results indicated that the gene trees of these loci are not congruent with the phylogeny based on 16s rrna gene. the ...200918972163
microcystin production in the tripartite cyanolichen peltigera leucophlebia.we show that the cyanobacterial symbionts of a tripartite cyanolichen can produce hepatotoxic microcystins in situ. microcystins were detected with high-performance liquid chromatography mass spectrometry both from cephalodia of the tripartite cyanolichen peltigera leucophlebia and from a symbiotic nostoc strain isolated from the same lichen specimen. genetic identities of symbiotic nostoc strains were studied by amplifying and sequencing the 16s rrna gene. also, the presence of the microcystin ...200919445594
water-stress induced trehalose accumulation and control of trehalase in the cyanobacterium nostoc punctiforme iam m-15.we investigated the biochemical properties of the enzymes involved in trehalose metabolism in the cyanobacterium nostoc punctiforme strain iam m-15 to elucidate the mechanism of trehalose accumulation in response to desiccation and salt stress. there was no detectable trehalose in fully hydrated n. punctiforme cells; however, these cells accumulated trehalose upon desiccation. moreover, nacl treatment also induced trehalose accumulation. the three genes for trehalose metabolism, trez (maltooligo ...200919436130
alteration of the gastrointestinal microbiota of mice by edible blue-green algae.to characterize the effect of edible blue-green algae (cyanobacteria) on the gastrointestinal microbiota of mice.200919486425
role of ntca, a cyanobacterial global nitrogen regulator, in the regulation of sucrose metabolism gene expression in anabaena sp. pcc 7120.in the heterocyst-forming cyanobacterium anabaena sp. pcc 7120 (also known as nostoc sp. pcc 7120), it has been shown that spsb and susa, the genes coding for proteins related to sucrose synthesis and cleavage, respectively, exhibit converse expression regarding the nitrogen source. in the nitrogen-fixing filament, spsb expression is mostly localized to the heterocysts and susa is only expressed in vegetative cells. the aim of this work was to investigate the participation of ntca, a global nitr ...200919082579
the role of the c-terminal region of cyanophycin synthetase from nostoc ellipsosporum ne1 in its enzymatic activity and thermostability: a key function of glu(856).the biosynthesis of cyanophycin granule polypeptides is catalyzed by cyanophycin synthetase, cpha. in this study, the role of the c-terminal region of cpha from nostoc ellipsosporum ne1, cpha(ne1), was analyzed using a tailor-made c-terminus truncated library. the expression level of truncated cpha(ne1) in e. coli depended on the stop codons that were used. the expression vector that had the amber stop codon tag produced more than twice amount of cpha(ne1) as a vector that contained the ochre co ...200918977318
hypocholesterolemic effect of nostoc commune var. sphaeroides kützing, an edible blue-green alga.intake of an edible blue-green alga nostoc commune var. sphaeroides kützing (n. commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect have not been elucidated.200919404563
diversity of 23s rrna genes within individual prokaryotic genomes.the concept of ribosomal constraints on rrna genes is deduced primarily based on the comparison of consensus rrna sequences between closely related species, but recent advances in whole-genome sequencing allow evaluation of this concept within organisms with multiple rrna operons.200919415112
analysis of current and alternative phenol based rna extraction methodologies for cyanobacteria.the validity and reproducibility of gene expression studies depend on the quality of extracted rna and the degree of genomic dna contamination. cyanobacteria are gram-negative prokaryotes that synthesize chlorophyll a and carry out photosynthetic water oxidation. these organisms possess an extended array of secondary metabolites that impair cell lysis, presenting particular challenges when it comes to nucleic acid isolation. therefore, we used the nhm5 strain of nostoc punctiforme atcc 29133 to ...200919660145
structure-function, stability, and chemical modification of the cyanobacterial cytochrome b6f complex from nostoc sp. pcc 7120.the crystal structure of the cyanobacterial cytochrome b(6)f complex has previously been solved to 3.0-a resolution using the thermophilic mastigocladus laminosus whose genome has not been sequenced. several unicellular cyanobacteria, whose genomes have been sequenced and are tractable for mutagenesis, do not yield b(6)f complex in an intact dimeric state with significant electron transport activity. the genome of nostoc sp. pcc 7120 has been sequenced and is closer phylogenetically to m. lamino ...200919189962
structural basis of murein peptide specificity of a gamma-d-glutamyl-l-diamino acid endopeptidase.the crystal structures of two homologous endopeptidases from cyanobacteria anabaena variabilis and nostoc punctiforme were determined at 1.05 and 1.60 a resolution, respectively, and contain a bacterial sh3-like domain (sh3b) and a ubiquitous cell-wall-associated nlpc/p60 (or chap) cysteine peptidase domain. the nlpc/p60 domain is a primitive, papain-like peptidase in the ca clan of cysteine peptidases with a cys126/his176/his188 catalytic triad and a conserved catalytic core. we deduced from st ...200919217401
immunolocalization of the uptake hydrogenase in the marine cyanobacterium lyngbya majuscula ccap 1446/4 and two nostoc strains.in n(2)-fixing cyanobacteria, the reduction of n(2) to nh(3) is coupled with the production of molecular hydrogen, which is rapidly consumed by an uptake hydrogenase, an enzyme that is present in almost all diazotrophic cyanobacteria. the cellular and subcellular localization of the cyanobacterial uptake hydrogenase remains uncertain, and it is definitely strain dependent. previous studies focused mainly on heterocystous cyanobacteria and used heterologous antisera. the present work represents t ...200919222582
biosynthesis of a linoleic acid allylic epoxide: mechanistic comparison with its chemical synthesis and leukotriene a biosynthesis.biosynthesis of the leukotriene a (lta) class of epoxide is a lipoxygenase-catalyzed transformation requiring a fatty acid hydroperoxide substrate containing at least three double bonds. here, we report on biosynthesis of a dienoic analog of lta epoxides via a different enzymatic mechanism. beginning with homolytic cleavage of the hydroperoxide moiety, a catalase/peroxidase-related hemoprotein from anabaena pcc 7120, which occurs in a fusion protein with a linoleic acid 9r-lipoxygenase, dehydrat ...200919244216
nitrogen fixation in mixed hylocomium splendens moss communities.the pleurocarpus feather moss, hylocomium splendens, is one of two co-dominant moss species in boreal forest ecosystems and one of the most common mosses on earth, yet little is known regarding its capacity to host cyanobacterial associates and thus contribute total ecosystem n. in these studies, we evaluated the n-fixation potential of the h. splendens-cyanobacteria association and contrasted the n-fixation activity with that of the putative n-fixing moss-cyanobacteria association of pleurozium ...200919252932
solid-phase/supercritical-fluid extraction for liquid chromatography of phenolic compounds in freshwater microalgae and selected cyanobacterial species.in the present paper a new extraction technique based on the combination of solid-phase/supercritical-fluid extraction (spe/sfe) with subsequent reversed-phase hplc is described. the spe/sfe extractor was originally constructed from spe-cartridge incorporated into the sfe extraction cell. selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acid), hydroxybenzaldehydes (4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde) and cinnamic acid d ...200919111311
new insights into the role of fur proteins: furb (all2473) from anabaena protects dna and increases cell survival under oxidative stress.fur (ferric uptake regulator) is a prokaryotic transcriptional regulator that controls a large number of genes mainly related to iron metabolism. several fur homologues with different physiological roles are frequently found in the same organism. the genome of the filamentous cyanobacterium anabaena (nostoc) sp. pcc 7120 codes for three different fur genes. fura is an essential protein involved in iron homoeostasis that also modulates dinitrogen fixation. fura interacts with haem, impairing its ...200918945213
diversity and transcription of proteases involved in the maturation of hydrogenases in nostoc punctiforme atcc 29133 and nostoc sp. strain pcc 7120.the last step in the maturation process of the large subunit of [nife]-hydrogenases is a proteolytic cleavage of the c-terminal by a hydrogenase specific protease. contrary to other accessory proteins these hydrogenase proteases are believed to be specific whereby one type of hydrogenases specific protease only cleaves one type of hydrogenase. in cyanobacteria this is achieved by the gene product of either hupw or hoxw, specific for the uptake or the bidirectional hydrogenase respectively. the f ...200919284580
characterization of the hupsl promoter activity in nostoc punctiforme atcc 29133.in cyanobacteria three enzymes are directly involved in the hydrogen metabolism; a nitrogenase that produces molecular hydrogen, h2, as a by-product of nitrogen fixation, an uptake hydrogenase that recaptures h2 and oxidize it, and a bidirectional hydrogenase that can both oxidize and produce h2.nostoc punctiforme atcc 29133 is a filamentous dinitrogen fixing cyanobacterium containing a nitrogenase and an uptake hydrogenase but no bidirectional hydrogenase. generally, little is known about the t ...200919284581
the 2a resolution crystal structure of hetl, a pentapeptide repeat protein involved in regulation of heterocyst differentiation in the cyanobacterium nostoc sp. strain pcc 7120.the hetl gene from the cyanobacterium nostoc sp. pcc 7120 encodes a 237 amino acid protein (25.6kda) containing 40 predicted tandem pentapeptide repeats. nostoc sp. pcc 7120 is a filamentous cyanobacterium that forms heterocysts, specialized cells capable of fixing atmospheric n(2) during nitrogen starvation in its aqueous environment. under these conditions, heterocysts occur in a regular pattern of approximately one out of every 10-15 vegetative cells. heterocyst differentiation is highly regu ...200918952182
gobase: an organelle genome database.the organelle genome database gobase, now in its 21st release (june 2008), contains all published mitochondrion-encoded sequences (approximately 913,000) and chloroplast-encoded sequences (approximately 250,000) from a wide range of eukaryotic taxa. for all sequences, information on related genes, exons, introns, gene products and taxonomy is available, as well as selected genome maps and rna secondary structures. recent major enhancements to database functionality include: (i) addition of an in ...200918953030
the naturally split npu dnae intein exhibits an extraordinarily high rate in the protein trans-splicing reaction.we have studied the naturally split alpha subunit of the dna polymerase iii (dnae) intein from nostoc punctiforme pcc73102 (npu) using purified proteins and determined an apparent first-order rate constant of (1.1+/-0.2)x10(-2) s(-1) at 37 degrees c. this represents the highest rate reported for the protein trans-splicing reaction so far (t(1/2) of approximately 60s). furthermore, the reaction was very robust and high-yielding with respect to different extein sequences, temperatures from 6 to 37 ...200919302791
characterization of a novel debranching enzyme from nostoc punctiforme possessing a high specificity for long branched chains.a novel debranching enzyme from nostoc punctiforme pcc73102 (npde) exhibits hydrolysis activity toward both alpha-(1,6)- and alpha-(1,4)-glucosidic linkages. the action patterns of npde revealed that branched chains are released first, and the resulting maltooligosaccharides are then hydrolyzed. analysis of the reaction with maltooligosaccharide substrates labeled with (14)c-glucose at the reducing end shows that npde specifically liberates glucose from the reducing end. kinetic analyses showed ...200919010304
molecular characterization and the effect of salinity on cyanobacterial diversity in the rice fields of eastern uttar pradesh, india.salinity is known to affect almost half of the world's irrigated lands, especially rice fields. furthermore, cyanobacteria, one of the critical inhabitants of rice fields have been characterized at molecular level from many different geographical locations. this study, for the first time, has examined the molecular diversity of cyanobacteria inhabiting indian rice fields which experience various levels of salinity.200919344531
bioinformatic and expression analyses of genes mediating zinc homeostasis in nostoc punctiforme.zinc homeostasis was investigated in nostoc punctiforme. cell tolerance to zn(2+) over 14 days showed that zncl(2) levels above 22 microm significantly reduced cell viability. after 3 days in 22 microm zncl(2), ca. 12% of the zn(2+) was in an edta-resistant component, suggesting an intracellular localization. zinquin fluorescence was detected within cells exposed to concentrations up to 37 microm relative to 0 microm treatment. radiolabeled (65)zn showed zn(2+) uptake increased over a 3-day peri ...200919011078
quantitative overview of n2 fixation in nostoc punctiforme atcc 29133 through cellular enrichments and itraq shotgun proteomics.nostoc punctiforme atcc 29133 is a photoautotrophic cyanobacterium with the capacity to fix atmospheric n 2. its ability to mediate this process is similar to that described for nostoc sp. pcc 7120, where vegetative cells differentiate into heterocysts. quantitative proteomic investigations at both the filament level and the heterocyst level are presented using isobaric tagging technology (itraq), with 721 proteins at the 95% confidence interval quantified across both studies. observations from ...200919012430
identification and quantification of microcystins from a nostoc muscorum bloom occurring in oukaïmeden river (high-atlas mountains of marrakech, morocco).health risks generated by cyanobacterial toxins in drinking and recreational waters are clearly recognised. during the monitoring programme on the distribution of toxic freshwater cyanobacteria in various water bodies including reservoirs, ponds and rivers of morocco, many toxigenic cyanobacteria bloom-forming species have been identified. particular attention was given to the investigation of the toxicology of a benthic nostoc species-nostoc muscorum ag. (cyanobacteria, nostocales, nostocaceae) ...200918288580
nmr resonance assignment of dnae intein from nostoc punctiforme.dnae intein from nostoc punctiforme (npu) is one of naturally occurring split inteins, which has robust protein splicing activity. highly efficient trans-splicing activity of npudnae intein could widen various biotechnological applications. however, structural basis of the efficient protein splicing activity is poorly understood. as a first step toward better understanding of protein trans-splicing mechanism, we present the backbone and side-chain resonance assignments of a single chain variant ...200919636943
site-specific two-color protein labeling for fret studies using split inteins.fluorescence resonance energy transfer (fret) is an ideal tool for studying protein conformational changes and dynamics. strategies to specifically label proteins with multiple colors at structurally important sites, a prerequisite for such studies, however, need to be devised on a protein-by-protein basis. here we describe a simple yet widely applicable two-color site-specific protein labeling method utilizing npu dnae split intein.200919645470
on the contributions of diffusion and thermal activation to electron transfer between phormidium laminosum plastocyanin and cytochrome f: brownian dynamics simulations with explicit modeling of nonpolar desolvation interactions and electron transfer events.the factors that determine the extent to which diffusion and thermal activation processes govern electron transfer (et) between proteins are debated. the process of et between plastocyanin (pc) and cytochrome f (cytf) from the cyanobacterium phormidium laminosum was initially thought to be diffusion-controlled but later was found to be under activation control (schlarb-ridley, b. g.; et al. biochemistry 2005, 44, 6232). here we describe brownian dynamics simulations of the diffusional associatio ...200919518050
a comparative genomics approach to understanding the biosynthesis of the sunscreen scytonemin in cyanobacteria.the extracellular sunscreen scytonemin is the most common and widespread indole-alkaloid among cyanobacteria. previous research using the cyanobacterium nostoc punctiforme atcc 29133 revealed a unique 18-gene cluster (npr1276 to npr1259 in the n. punctiforme genome) involved in the biosynthesis of scytonemin. we provide further genomic characterization of these genes in n. punctiforme and extend it to homologous regions in other cyanobacteria.200919630972
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