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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
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
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
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
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
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
[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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
[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
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
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
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
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
production of the neurotoxin bmaa by a marine cyanobacterium.diverse species of cyanobacteria have recently been discovered to produce the neurotoxic non-protein amino acid beta-methylamino-l-alanine (bmaa). in guam, bmaa has been studied as a possible environmental toxin in the diets of indigenous chamorro people known to have high levels of amyotrophic lateral sclerosis/ parkinsonism dementia complex (als/pdc). bmaa has been found to accumulate in brain tissues of patients with progressive neurodegenerative illness in north america. in guam, bmaa was fo ...200718463731
[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
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
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
tyrosine-induced heterocyst division in nostoc muscorum.heterocyst size variation in nostoc muscorum has been surveyed in the presence and absence of tyrosine. the heterocyst size exhibited two major peaks under both conditions but one of the peaks shifted towards larger size in tyrosine-containing medium. heterocysts of larger volume exhibited division in the latter medium which was not observed in medium lacking tyrosine. it is suggested that signals for cell division did not decay following differentiation of heterocyst in the presence of tyrosine ...198718425684
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
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
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
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
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
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
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
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
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
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
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
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
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
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
isolation and characterization of thylakoid membranes from the filamentous cyanobacterium nostoc punctiforme.nostoc punctiforme strain pasteur culture collection (pcc) 73102, a sequenced filamentous cyanobacterium capable of nitrogen fixation, is used as a model organism for characterization of bioenergetic processes during nitrogen fixation in nostoc. a protocol for isolating thylakoid membranes was developed to examine the biochemical and biophysical aspects of photosynthetic electron transfer. thylakoids were isolated from filaments of n. punctiforme by pneumatic pressure-drop lysis. the activity of ...200718251853
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
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
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
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
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
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
[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
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
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
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
a gene cluster that regulates both heterocyst differentiation and pattern formation in anabaena sp. strain pcc 7120.wild-type anabaena sp. strain pcc 7120, a filamentous nitrogen-fixing cyanobacterium, produces single heterocysts at semi-regular intervals. asr0100 (patu5) and alr0101 (patu3) are homologous to the 5' and 3' portions of patu of nostoc punctiforme. alr0099 (hetz) overlaps the 5' end of patu5. hetz, patu5 and patu3 were all upregulated, or expressed specifically, in proheterocysts and heterocysts. mutants of hetz showed delayed or no heterocyst differentiation. in contrast, a patu3 mutation produ ...200718045384
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
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
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
effect of uv-b and high visual radiation on photosynthesis in freshwater (nostoc spongiaeforme) and marine (phormidium corium) cyanobacteria.human activity is causing depletion of ozone in stratosphere, resulting in increased uv-b radiation and global warming. however, impact of these climatic changes on the aquatic organism (especially marine) is not fully understood. here, we have studied the effect of excess uv-b and visible radiation on photosynthetic pigments, fatty acids content, lipid peroxidation, nitrogen content, nitrogen reductase activity and membrane proteins, induction of mycosporine-like amino acids (maas) and antioxid ...200717970281
free radical scavenging and antioxidant enzymes activation of polysaccharide extract from nostoc sphaeroides.nostoc sphaeroides kuetzing has been used as a traditional medicine in china to treat a variety of ailments. this research identified the antioxidant activities of polysaccharide extract from nostoc sphaeroides. the extract, which contains 46.2% carbohydrates, exhibited an effective scavenging capability on superoxide radical, hydroxyl radicals in non site-specific as well as site-specific assays, and also performed lipid peroxidation inhibition in a dose-dependent manner. polysaccharide extract ...200717963327
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
structural and functional characterization of galactooligosaccharides in nostoc commune: beta-d-galactofuranosyl-(1-->6)-[beta-d-galactofuranosyl-(1-->6)]2-beta-d-1,4-anhydrogalactitol and beta-(1-->6)-galactofuranosylated homologues.a new class of galactooligosaccharides has been identified from the terrestrial cyanobacterium nostoc commune by ms and nmr techniques. these consist of beta-d-galactofuranosyl-(1-->6)-[beta-d-galactofuranosyl-(1-->6)]n-beta-d-1,4-anhydrogalactitols with n ranging from 2 to 8, corresponding to compounds designated 1 through 7. in total these saccharides amounted to approximately 0.35% of the dry thallus of n. commune, while in several other cyanobacteria they were not detected. possibly they pla ...200717935705
effects of disruption of homocitrate synthase genes on nostoc sp. strain pcc 7120 photobiological hydrogen production and nitrogenase.in the case of nitrogenase-based photobiological hydrogen production systems of cyanobacteria, the inactivation of uptake hydrogenase (hup) leads to significant increases in hydrogen production activity. however, the high-level-activity stage of the hup mutants lasts only a few tens of hours under air, a circumstance which seems to be caused by sufficient amounts of combined nitrogen supplied by active nitrogenase. the catalytic femo cofactor of nitrogenase binds homocitrate, which is required f ...200717933939
cross-talk between iron and nitrogen regulatory networks in anabaena (nostoc) sp. pcc 7120: identification of overlapping genes in fura and ntca regulons.nitrogen signalling in cyanobacteria involves a complex network in which the availability of iron plays an important role. in the nitrogen-fixing cyanobacterium anabaena sp. pcc 7120, iron uptake is controlled by fura, while ntca is the master regulator of nitrogen metabolism and shows a mutual dependence with hetr in the first steps of heterocyst development. expression of fura is modulated by ntca and it is enhanced in a hetr(-) background. iron starvation in cells grown in the presence of com ...200717920076
recurrent adenylation domain replacement in the microcystin synthetase gene cluster.microcystins are small cyclic heptapeptide toxins produced by a range of distantly related cyanobacteria. microcystins are synthesized on large nrps-pks enzyme complexes. many structural variants of microcystins are produced simultaneously. a recombination event between the first module of mcyb (mcyb1) and mcyc in the microcystin synthetase gene cluster is linked to the simultaneous production of microcystin variants in strains of the genus microcystis.200717908306
lyase activities of cpcs- and cpct-like proteins from nostoc pcc7120 and sequential reconstitution of binding sites of phycoerythrocyanin and phycocyanin beta-subunits.genes all5292 (cpcs2) and alr0617 (cpcs1) in the cyanobacterium nostoc pcc7120 are homologous to the biliprotein lyase cpcs, and genes all5339 (cpct1) and alr0647 (cpct2) are homologous to the lyase cpct. the functions of the encoded proteins were screened in vitro and in a heterologous escherichia coli system with plasmids conferring biosynthesis of the phycocyanobilin chromophore and of the acceptor proteins beta-phycoerythrocyanin (pecb) or beta-phycocyanin (cpcb). cpct1 is a regioselective b ...200717895251
action spectrum for developmental photo-induction of the blue-green alga nostoc muscorum.the dark-grown cyanophyte requires a brief exposure to light from the 650 mmicro region of the spectrum before it can complete its developmental cycle. induction is reversed by exposure to green light. a blue protein, presumably allophycocyanin (absorption maximum, 650 mmicro) has been demonstrated in aqueous extracts of the cyanophycean cells.196217836542
identification and expression analyses of putative sesquiterpene synthase genes in phormidium sp. and prevalence of geoa-like genes in a drinking water reservoir.the occurrence of taste and odor problems in drinking water supplies is a widespread phenomenon. from a saxonian water reservoir we isolated a cyanobacterial species which was classified as phormidium sp. under laboratory conditions it produced an earthy-musty smell due to the synthesis of geosmin. the only genes shown to be involved in geosmin biosynthesis are cyc2 and geoa of streptomyces. based on the alignment of cyc2 with a putative sesquiterpene synthase of nostoc punctiforme, a degenerate ...200717827321
algae: nitrogen fixation by antarctic species.algae from terrestrial and fresh-water habitats in antarctica were examined for ability to fix atmospheric nitrogen. nostoc commune was the only species capable of growing in nitrogen-free medium; nitrogen fixation by this species was verified by assimilation of n(15). the importance of nitrogen-fixing algae to terrestrial life in the antarctic is discussed.196317812987
gas vacuole development in a blue-green alga.de novo productioni of gas vacutoles can be induced in the blue-green alga nostoc muscorum by transferring the cells from a defined medium to distilled water. the unusual ultrastructure of the gas vacuole membranes permits their easy recognition when specimens are prepared for electron microscopy by freeze-etching. the youngest gas vacuoles are biconical organelles; 48 hours after induction the gas vacuoles reach their miaximum observed length when they are cylinders (1.5 by 0.1 micro) with corn ...196917807814
desaturase genes in a psychrotolerant nostoc sp. are constitutively expressed at low temperature.antarctic psychrotolerant, nostoc sp. (so-36), when grown at 25 degrees c and then shifted to 10 degrees c, showed an increase in the tri-unsaturated fatty acid [c(18:3(9,12,15))] at the expense of mono- [c(18:1(9))] and di-unsaturated [c(18:2(9,12))] fatty acids. these results indicate that the activities of the enzymes desa and desb are up-regulated, when cultures were grown at 10 degrees c or shifted to 10 degrees c from 25 degrees c. however, rt-pcr studies indicated a constitutive expressio ...200717697671
nanoscale visualization of a fibrillar array in the cell wall of filamentous cyanobacteria and its implications for gliding motility.many filamentous cyanobacteria are motile by gliding, which requires attachment to a surface. there are two main theories to explain the mechanism of gliding. according to the first, the filament is pushed forward by small waves that pass along the cell surface. in the second, gliding is powered by the extrusion of slime through pores surrounding each cell septum. we have previously shown that the cell walls of several motile cyanobacteria possess an array of parallel fibrils between the peptido ...200717693519
anti-herpes simplex virus target of an acidic polysaccharide, nostoflan, from the edible blue-green alga nostoc flagelliforme.the acidic polysaccharide nostoflan was previously isolated as an antiviral component from the terrestrial alga nostoc flagelliforme. in the present study, we examined the target for its anti-herpes simplex virus type 1 action. in time-of-addition experiments, the most sensitive stage of viral replication to nostoflan was found to be early events, including the virus binding and/or penetration processes. in order to determine what extent nostoflan may be involved in these processes, virus bindin ...200717666824
desensitization of soluble guanylyl cyclase, the no receptor, by s-nitrosylation.the molecular mechanism of desensitization of soluble guanylyl cyclase (sgc), the no receptor, has long remained unresolved. posttranslational modification and redox state have been postulated to affect sgc sensitivity to no but evidence has been lacking. we now show that sgc can be s-nitrosylated in primary aortic smooth muscle cells by s-nitrosocysteine (csno), an s-nitrosylating agent, in human umbilical vein endothelial cells after vascular endothelial growth factor treatment and in isolated ...200717636120
transcription and regulation of the bidirectional hydrogenase in the cyanobacterium nostoc sp. strain pcc 7120.the filamentous, heterocystous cyanobacterium nostoc sp. strain pcc 7120 (anabaena sp. strain pcc 7120) possesses an uptake hydrogenase and a bidirectional enzyme, the latter being capable of catalyzing both h2 production and evolution. the completely sequenced genome of nostoc sp. strain pcc 7120 reveals that the five structural genes encoding the bidirectional hydrogenase (hoxefuyh) are separated in two clusters at a distance of approximately 8.8 kb. the transcription of the hox genes was exam ...200717630298
purification and characterization of corrinoid-compounds from the dried powder of an edible cyanobacterium, nostoc commune (ishikurage).vitamin b12 content (98.8 +/- 5.6 microg/100 g dry weight) of an edible cyanobacterium, nostoc commune (ishikurage) was determined by the lactobacillus delbrueckii atcc 7830 microbiological method. bioautography with vitamin b12-dependent escherichia coli 215 indicated that n. commune contained two (main and minor) corrinoid-compounds. these corrinoid-compounds were purified to homogeneity from the dried algal cells and characterized. the main and minor purified corrinoid-compounds were identifi ...200717616007
l-amino acid oxidases with specificity for basic l-amino acids in cyanobacteria.the two closely related fresh water cyanobacteria synechococcus elongatus pcc 6301 and synechococcus elongatus pcc 7942 have previously been shown to constitutively express a fad-containing l-amino acid oxidase with high specificity for basic l-amino acids (l-arginine being the best substrate). in this paper we show that such an enzyme is also present in the fresh water cyanobacterium synechococcus cedrorum pcc 6908. in addition, an improved evaluation of the nucleotide/amino acid sequence of th ...200717542496
effects of periodic desiccation on the synthesis of the uv-screening compound, scytonemin, in cyanobacteria.scytonemin is an ultraviolet radiation (uvr)-screening compound synthesized by some sheathed cyanobacteria exposed to high solar and sky radiation. it is primarily produced in response to uva radiation, but certain environmental stresses can enhance synthesis. this study focuses on the effects of periodic desiccation on scytonemin synthesis in three desiccation-tolerant cyanobacterial strains, nostoc punctiforme pcc 73102, chroococcidiopsis ccmee 5056 and chroococcidiopsis ccmee 246. nostoc punc ...200717504482
reconstitution of modular pdk1 functions on trans-splicing of the regulatory ph and catalytic kinase domains.the serine-threonine protein kinases pdk1 and pkb each contain a pleckstrin homology (ph) domain that binds the membrane-bound phosphatidylinositol 3,4,5-triphosphate [pi(3,4,5)p3] second messenger and is required for pdk1-catalyzed phosphorylation and activation of pkb. while x-ray structures have been reported for the individual regulatory ph and catalytic kinase domain constructs of both pdk1 and pkb, diffraction quality crystals of full length constructs have yet to be obtained, likely due t ...200717500509
global gene expression patterns of nostoc punctiforme in steady-state dinitrogen-grown heterocyst-containing cultures and at single time points during the differentiation of akinetes and hormogonia.the vegetative cells of the filamentous cyanobacterium nostoc punctiforme can differentiate into three mutually exclusive cell types: nitrogen-fixing heterocysts, spore-like akinetes, and motile hormogomium filaments. a dna microarray consisting of 6,893 n. punctiforme genes was used to identify the global transcription patterns at single time points in the three developmental states, compared to those in ammonium-grown time zero cultures. analysis of ammonium-grown cultures yielded a transcript ...200717483217
the anabaena sp. strain pcc 7120 asr1734 gene encodes a negative regulator of heterocyst development.the novel asr1734 gene of anabaena (nostoc) sp. strain pcc 7120 inhibited heterocyst development when present in extra copies. overexpression of asr1734 inhibited heterocyst development in several strains including the wild type and two strains that form multiple contiguous heterocysts (mch phenotype): a pats null mutant and a hetr(r223w) mutant. overexpression of asr1734 also caused increased nbla messenger rna levels, and increased loss of autofluorescence in vegetative cells throughout filame ...200717462023
molecular analysis of genes in nostoc punctiforme involved in pilus biogenesis and plant infection.hormogonia are the infective agents in many cyanobacterium-plant symbioses. pilus-like appendages are expressed on the hormogonium surface, and mutations in pil-like genes altered surface piliation and reduced symbiotic competency. this is the first molecular evidence that pilus biogenesis in a filamentous cyanobacterium requires a type iv pilus system.200717416648
oxylipin formation in nostoc punctiforme (pcc73102).the dioxygenation of polyunsaturated fatty acids is mainly catalyzed by members of the lipoxygenase enzyme family in flowering plants and mosses. lipoxygenase products can be metabolized further and are known as signalling substances that play a role in plant development as well as in plant responses to wounding and pathogen attack. apart from accumulating data in mammals, flowering and non-flowering plants, information on the relevance of lipid peroxide metabolism in prokaryotic organisms is sc ...200717412376
m. tuberculosis ser/thr protein kinase d phosphorylates an anti-anti-sigma factor homolog.receptor ser/thr protein kinases are candidates for sensors that govern developmental changes and disease processes of mycobacterium tuberculosis (mtb), but the functions of these kinases are not established. here, we show that mtb protein kinase (pkn) d overexpression alters transcription of numerous bacterial genes, including rv0516c, a putative anti-anti-sigma factor, and genes regulated by sigma factor f. the pknd kinase domain directly phosphorylated rv0516c, but no other sigma factor regul ...200717411339
biosorption of cr(vi) by immobilized biomass of two indigenous strains of cyanobacteria isolated from metal contaminated soil.biosorption of cr(vi) using native strains of cyanobacteria from metal contaminated soil in the premises of textile mill has been reported in this paper. biosorption was studied as a function of ph (1-5), contact time (5-180 min) and initial chromium ion concentration (5-20mg/l) to find out the maximum biosorption capacity of alginate immobilized nostoc calcicola hh-12 and chroococcus sp. hh-11. the optimum conditions for cr(vi) biosorption are almost same for the two strains (ph 3-4, contact ti ...200717403568
anti-proliferative effects of recombinant iron superoxide dismutase on hepg2 cells via a redox-dependent pi3k/akt pathway.the coding sequence for an iron superoxide dismutase (fe-sod) was amplified from the nostoc commune genome. recombinant fe-sod was overexpressed in escherichia coli, accounting for approximately 76% of total bacterial protein. fe-sod was purified from bacterial lysate by ni-nta column chromatography and used to generate an anti-sod antibody. the purified fe-sod was encapsulated in liposomes and delivered to hepg2 liver tumor cells to eliminate cellular superoxide anions. the sod-loaded cells exh ...200717387468
structural characterization of the fusion of two pentapeptide repeat proteins, np275 and np276, from nostoc punctiforme: resurrection of an ancestral protein.the nostoc punctiforme genes np275 and np276 are two adjacently encoded proteins of 98 and 75 amino acids in length and exhibit sequences composed of tandem pentapeptide repeats. the structures of np275 and a fusion of np275 and np276 were determined to 2.1 and 1.5 a, respectively. the two nostoc proteins fold as highly symmetric right-handed quadrilateral beta-helices similar to the mycobacterial protein mfpa implicated in fluoroquinolone resistance and dna gyrase inhibition. the sequence compo ...200717384236
three distinct clades of cultured heterocystous cyanobacteria constitute the dominant n2-fixing members of biological soil crusts of the colorado plateau, usa.the identity of the numerically dominant n(2)-fixing bacteria in biological soil crusts of the colorado plateau region and two outlying areas was determined using multiple approaches, to link the environmental diversity of nifh gene sequences to cultured bacterial isolates from the regions. of the nifh sequence-types detected in soil crusts of the colorado plateau, 89% (421/473) were most closely related to nifh signature sequences from cyanobacteria of the order nostocales. n(2)-fixing cyanobac ...200717381526
group 3 sigma factor gene, sigj, a key regulator of desiccation tolerance, regulates the synthesis of extracellular polysaccharide in cyanobacterium anabaena sp. strain pcc 7120.the changes in the expression of sigma factor genes during dehydration in terrestrial nostoc hk-01 and aquatic anabaena pcc 7120 were determined. the expression of the sigj gene in terrestrial nostoc hk-01, which is homologous to sigj (alr0277) in aquatic anabaena pcc 7120, was significantly induced in the mid-stage of dehydration. we constructed a higher-expressing transformant of the sigj gene (he0277) in anabaena pcc 7120, and the transformant acquired desiccation tolerance. the results of an ...200717376888
cloning of lipoxygenase genes from a cyanobacterium, nostoc punctiforme, and its expression in eschelichia coli.oxylipin metabolism represents one of the important hormonal and defensive mechanisms employed by plants, algae, or animals. it begins mostly with the reaction of lipoxygenases (loxs), which catalyze the oxygenation of polyunsaturated fatty acids to form the corresponding hydroperoxides. at present, little information about loxs in cyanobacteria has been reported. herein, we report the first isolation of two lox genes (nplox1 and nplox2) from a cyanobacterium, nostoc punctiforme atcc29133. incub ...200717375360
molecular genetics and genomic analysis of scytonemin biosynthesis in nostoc punctiforme atcc 29133.the indole-alkaloid scytonemin is the most common and widespread sunscreen among cyanobacteria. previous research has focused on its nature, distribution, ecology, physiology, and biochemistry, but its molecular genetics have not been explored. in this study, a scytonemin-deficient mutant of the cyanobacterium nostoc punctiforme atcc 29133 was obtained by random transposon insertion into open reading frame npr1273. the absence of scytonemin under conditions of induction by uv irradiation was the ...200717351042
fura modulates gene expression of alr3808, a dpsa homologue in nostoc (anabaena) sp. pcc7120.the dna-binding protein from stationary phase (dps) protein family plays an important role in protecting microorganisms from oxidative and nutritional stresses. in silico analysis of the promoter region of alr3808, a dpsa homologue from the cyanobacterium nostoc sp. pcc7120 shows putative iron-boxes with high homology with those recognized by fura (ferric uptake regulator). evidence for the modulation of dpsa by fura was obtained using in vitro and in vivo approaches. selex linked to pcr was use ...200717350003
cofactor regeneration in phototrophic cyanobacteria applied for asymmetric reduction of ketones.the obligate photoautotrophic cyanobacterium synechococcus pcc7942 and the photoheterotrophic heterocystous cyanobacterium noctoc muscorum are able to reduce prochiral ketones asymmetrically to optical pure chiral alcohols without light. an example is the synthesis of s-pentafluoro(phenyl-)ethanol with an enantiomeric excess >99% if 2'-3'-4'-5'-6'-pentafluoroacetophenone is used as substrate. if no light is available for regeneration of the cofactor nicotinamide adenine dinucleotide phosphate (r ...200717345080
mutations stabilize small subunit ribosomal rna in desiccation-tolerant cyanobacteria nostoc.the ribosomal rna molecule is an ideal model for evaluating the stability of a gene product under desiccation stress. we isolated 8 nostoc strains that had the capacity to withstand desiccation in habitats and sequenced their 16s rrna genes. the stabilities of 16s rrnas secondary structures, indicated by free energy change of folding, were compared among nostoc and other related species. the results suggested that 16s rrna secondary structures of the desiccation-tolerant nostoc strains were more ...200717334839
carbamidocyclophanes a-e, chlorinated paracyclophanes with cytotoxic and antibiotic activity from the vietnamese cyanobacterium nostoc sp.five new paracyclophanes, carbamidocyclophanes a-e (1-5), characterized by carbamido side chains at a symmetric [7.7]paracyclophane ring, have been isolated from the biomass of the vietnamese nostoc sp. cavn 10. structure elucidation by spectroscopic methods showed that 1-5 vary in the substitution pattern of the chlorinated butyl side chains. the compounds exhibited cytotoxic activity against mcf-7 (breast cancer cell line) and fl cells (human amniotic epithelial cell line) and moderate antibac ...200717311455
insight into the radical mechanism of phycocyanobilin-ferredoxin oxidoreductase (pcya) revealed by x-ray crystallography and biochemical measurements.the x-ray crystal structure of the substrate-free form of phycocyanobilin (pcb)-ferredoxin oxidoreductase (pcya; ec 1.3.7.5) from the cyanobacterium nostoc sp. pcc7120 has been solved at 2.5 a resolution. a comparative analysis of this structure with those recently reported for substrate-bound and substrate-free forms of pcya from the cyanobacterium synechocystis sp. pcc6803 (hagiwara et al. (2006) proc. natl. acad. sci. u.s.a. 103, 27-32; hagiwara et al. (2006) febs lett. 580, 3823-3828) provid ...200717279614
an itraq-based quantitative analysis to elaborate the proteomic response of nostoc sp. pcc 7120 under n2 fixing conditions.nostoc sp. pcc 7120 is an oxygen-evolving photoautotrophic n2 fixing filamentous cyanobacterium. upon nitrogen starvation, a range of processes are initiated, such as differentiation of the heterocysts, specific cells where n2 fixation takes place. we have characterized and quantified the proteome of the nostoc sp. pcc 7120 wild-type strain grown under n2 fixing and non-n2 fixing conditions. to assess global proteome changes in response to environmental changes, measurements were made using the ...200717269719
proteomic analyses of the photoauto- and diazotrophically grown cyanobacterium nostoc sp. pcc 73102.the filamentous cyanobacteria of the genus nostoc are globally distributed, phenotypically complex organisms, capable of cellular differentiation and of forming symbiotic associations with a wide range of plants. to further our understanding of these processes and functions, the proteome of photoautotrophically and diazotrophically grown nostoc sp. pcc 73102 (n. punctiforme) cells was examined. extracted proteins were separated into membrane and soluble protein fractions and analysed using two-d ...200717259633
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