Publications

pigment analysis and ammonia excretion in herbicide tolerant cyanobacteria.	isolation of cyanobacteria was attempted from herbicide applied rice soils. the predominant genera were westiellopsis followed by anabaena, nostoc and oscillatoria. the herbicide tolerance was further tested by growing the cyanobacterial cultures in bg-11 medium supplemented with varying concentrations of the commonly used rice herbicide, viz butachlor under in vitro condition. the chlorophyll-a, phycobiliproteins and ammonia excretion were assessed at periodic intervals. westiellopsis showed th ...	2002	12597026
lateral gene transfer and ancient paralogy of operons containing redundant copies of tryptophan-pathway genes in xylella species and in heterocystous cyanobacteria.	tryptophan-pathway genes that exist within an apparent operon-like organization were evaluated as examples of multi-genic genomic regions that contain phylogenetically incongruous genes and coexist with genes outside the operon that are congruous. a seven-gene cluster in xylella fastidiosa includes genes encoding the two subunits of anthranilate synthase, an aryl-coa synthetase, and trpr. a second gene block, present in the anabaena/nostoc lineage, but not in other cyanobacteria, contains a near ...	2003	12620124
cloning and expression of a putative cyclodextrin glucosyltransferase from the symbiotically competent cyanobacterium nostoc sp. pcc 9229.	a polymerase chain reaction-based method was used to isolate a nostoc sp. pcc 9229 cdna from infected glands of gunnera chilensis. the complete gene sequence was isolated from a genomic nostoc sp. pcc 9229 library. sequence analysis showed 84% amino acid similarity to a putative cyclodextrin glycosyltransferase from nostoc sp. pcc 7120 and the gene was therefore termed cgt. southern blot revealed that the cgt gene was present in symbiotically competent cyanobacteria. the cgt gene was expressed i ...	2003	12620618
demonstration of a sensory rhodopsin in eubacteria.	we report the first sensory rhodopsin observed in the eubacterial domain, a green light-activated photoreceptor in anabaena (nostoc) sp. pcc7120, a freshwater cyanobacterium. the gene encoding the membrane opsin protein of 261 residues (26 kda) and a smaller gene encoding a soluble protein of 125 residues (14 kda) are under the same promoter in a single operon. the opsin expressed heterologously in escherichia coli membranes bound all-trans retinal to form a pink pigment (lambda max 543 nm) with ...	2003	12622809
a two-component system mediates developmental regulation of biosynthesis of a heterocyst polysaccharide.	some cyanobacteria couple oxygenic photosynthesis in vegetative cells with o2-sensitive n2 fixation in differentiated cells called heterocysts. heterocyst differentiation involves extensive biochemical and structural changes that collectively permit heterocysts to assimilate n2 aerobically and supply the products of n2 fixation to vegetative cells. hepk and devr are required for the development of functional heterocysts in anabaena and nostoc, respectively. we show that hepk is an autokinase and ...	2003	12637541
heterocyst-specific expression of patb, a gene required for nitrogen fixation in anabaena sp. strain pcc 7120.	the patb gene product is required for growth and survival of the filamentous cyanobacterium anabaena sp. strain pcc 7120 in the absence of combined nitrogen. a patb::gfp fusion demonstrated that this gene is expressed exclusively in heterocysts. patb mutants have a normal initial pattern of heterocyst spacing along the filament but differentiate excess heterocysts after several days in the absence of combined nitrogen. expression of hetr and pats, two critical regulators of the heterocyst develo ...	2003	12644502
genetic polymorphism of cyanobacteria under permanent natural stress: a lesson from the "evolution canyons".	cyanobacteria have high adaptive potential and occur in the most extreme habitats. the available literature data indicate that the versatility of cyanobacteria is related to their higher polymorphism under stress. the studies of a filamentous cyanobacterium, nostoc linckia, from the ecological microsite models known as "evolution canyons" showed that, among the evolutionary forces maintaining the higher polymorphism and genome diversity under permanent natural stress, the various types of natura ...	2003	12648721
effects of uv and visible light on cyanobacteria at the cellular level.	the effect of uv and visible light on cyanobacteria was determined at the cellular level by means of epifluorescence and confocal microscopy techniques. these methods allow the examination of light effects in spatial resolution. series of measurements were performed to determine the effect of different light qualities and quantities on cyanobacteria. to analyze the effect of the light quality, samples of anabaena and scytonema sp. were exposed to intense blue, green or red light applied from the ...	2002	12659496
wavelength-dependent induction of a mycosporine-like amino acid in a rice-field cyanobacterium, nostoc commune: role of inhibitors and salt stress.	wavelength-dependent induction of a mycosporine-like amino acid (maa) was studied in a nitrogen-fixing rice-field cyanobacterium, nostoc commune. hplc studies showed the presence of shinorine, a bisubstituted maa containing both glycine and serine groups and having an absorption maximum at 334 nm. exposure of cultures to simulated solar radiation in combination with various cut-off filters (wg 280, 295, 305, 320, 335, 345, gg 400, 420, 455, 475, og 515, 530, 570, rg 645, 665; all schott filter s ...	2003	12664980
cyanovirin-n: a sugar-binding antiviral protein with a new twist.	cyanovirin-n (cv-n), an 11-kda protein from the cyanobacterium nostoc ellipsosporum, is a highly potent virucidal agent that has generated interest as a lead natural product for the prevention and chemotherapy of human immunodeficiency virus infection. the antiviral activity of cv-n is mediated through specific, high-affinity interactions with the viral surface envelope glycoproteins. a number of structures of wild-type, mutant and sequence-shuffled cv-n have been solved by nuclear magnetic reso ...	2003	12678493
extracellular polysaccharide synthesis by nostoc strains as affected by n source and light intensity.	a study on the effect of two of the main factors affecting energy flux in n(2)-fixing cyanobacteria, i.e. light intensity and availability of combined nitrogen, on the synthesis of soluble exopolysaccharides was carried out with three strains of the genus nostoc (pcc 7413, pcc 7936, and pcc 8113) presenting different capsular polysaccharidic morphologies and released polysaccharide productions. strains acclimated to diazotrophic and non-diazotrophic conditions were cultured at high and low light ...	2003	12697392
[associative cyanobacteria isolated from the roots of epiphytic orchids].	associative cyanobacteria were isolated from the rhizoplane and velamen of the aerial roots of the epiphytic orchids acampe papillosa, phalaenopsis amabilis, and dendrobium moschatum and from the substrate roots of acampe papillosa and dendrobium moschatum. cyanobacteria were isolated on complete and nitrogen-free variants of bg-11 medium. on all media and in all samples, cyanobacteria of the genus nostoc predominated. nostoc, anabaena, and calothrix were isolated from the surface of the a. papi ...	2003	12698800
presence and expression of hydrogenase specific c-terminal endopeptidases in cyanobacteria.	hydrogenases catalyze the simplest of all chemical reactions: the reduction of protons to molecular hydrogen or vice versa. cyanobacteria can express an uptake, a bidirectional or both nife-hydrogenases. maturation of those depends on accessory proteins encoded by hyp-genes. the last maturation step involves the cleavage of a ca. 30 amino acid long peptide from the large subunit by a c-terminal endopeptidase. until know, nothing is known about the maturation of cyanobacterial nife-hydrogenases. ...	2003	12735794
effect of three nitrophenols on carbon metabolism in nostoc muscorum and chlorella vulgaris.	carbon metabolism in selected strains of nostoc muscorum and chlorella vulgaris grown in the presence of three nitrophenols [o-nitrophenol, m-nitrophenol and 2,4-dinitrophenol] was assessed by examining activities of the enzymes such as amylase, starch phosphorylase, fructose 1,6-biphosphatase, sucrose phosphate synthase, and invertase. marked alterations were observed in activities of the enzymes involved in starch metabolism. the cellular content of starch in nitrophenol-grown cultures was sig ...	2003	12742367
ultrastructure of the cyanobacterium nostoc muscorum and exploitation of the culture for hydrogen production.	an effect of various physico-chemical parameters on nitrogenase-catalyzed oxygen-free hydrogen production by nostoc muscorum was demonstrated. more hydrogen was produced in the light than in the dark. optimum temperature was 40 degrees c various sugars increased hydrogen production whereas on easily metabolized nitrogen sources it was inhibited. the production was sensitive to salinity and fe3+, cu2+, zn2+ and ni2+ ions. ultrastructural study revealed many electron-dense layers outside the cell- ...	2003	12744079
fatty acid composition of six freshwater wild cyanobacterial species.	hydroxy, n-saturated, branched, dioic, and unsaturated fatty acids in six freshwater wild cyanobacteria (chroococcus minutus, lyngbya ceylanica, merismopedia glauca, nodularia sphaerocarpa, nostoc linckia, and synechococcus aeruginosus) collected from different lakes and springs of israel have been identified by gas chromatography-mass spectrometry (gc-ms).	2003	12744080
protective role of certain chemicals against uv-b-induced damage in the nitrogen-fixing cyanobacterium, nostoc muscorum.	the protective effects of l-cysteine, ascorbic acid, reduced glutathione, l-tryptophan, and sodium pyruvate against uv-b-induced damages were studied in the nitrogen-fixing cyanobacterium, nostoc muscorum. when added to the culture suspension during uv-b treatment, these chemicals caused a significant protective effect on survival and growth of the organism. sodium pyruvate conferred the strongest protection whereas the weakest effect was elicited by tryptophan. a 20 min exposure of a culture su ...	2003	12746856
[role of the heterotrophic bacteria associated with the cyanobacterium nostoc muscorum in cadmium sulfide synthesis].		2003	12751257
mutational engineering of the cyanobacterium nostoc muscorum for resistance to growth-inhibitory action of licl and nacl.	the effect of nacl on two vital processes of cyanobacterial metabolism, viz. n(2) fixation and oxygenic photosynthesis, was studied in the cyanobacterium nostoc muscorum grown diazotrophically. an increase in nacl concentration suppressed the formation of heterocyst and adversely affected the nitrogenase activity in the parent, whereas in li(+)-r and na(+)-r mutants nacl stress did not cause any adverse effect. the rate of photosynthetic o(2)-evolution was also adversely affected by the nacl str ...	2003	12783185
genomic dna of nostoc commune (cyanobacteria) becomes covalently modified during long-term (decades) desiccation but is protected from oxidative damage and degradation.	genomic dna of nostoc commune (cyanobacteria) became covalently modified during decades of desiccation. amplification of gene loci from desiccated cells required pretreatment of dna with n-phenacylthiazolium bromide, a reagent that cleaves dna- and protein-linked advanced glycosylation end-products. dna from 13 year desiccated cells did not show any higher levels of the commonly studied oxidatively modified dna damage biomarkers 8-hydroxyguanine, 8-hydroxyadenine and 5-hydroxyuracil, compared to ...	2003	12799425
molecular characterization of endolithic cyanobacteria inhabiting exposed dolomite in central switzerland.	the phototrophic microbial community inhabiting exposed dolomite in the alpine piora valley (switzerland) forms a distinct endolithic bilayer that features adjacent red dolomite (exterior) and green dolomite (interior) layers that are c. 0.5-1 mm below the rock surface. characterization of the community, with an emphasis on cyanobacteria, was conducted with culture-dependent and -independent approaches. direct microscopy of green dolomite revealed four distinct morphotypes consistent with chloro ...	2003	12823194
sequence analysis and biochemical characterization of the nostopeptolide a biosynthetic gene cluster from nostoc sp. gsv224.	the cloning, sequencing, annotation and biochemical analysis of the nostopeptolide (nos) biosynthetic gene cluster from the terrestrial cyanobacterium nostoc sp. gsv224 is described. nostopeptolides a1 and a2 are cyclic peptide-polyketide hybrid natural products possessing nine amino acid residues, a butyric acid group, and an internal acetate-derived unit that are linked by peptide and ester bonds. the nos gene cluster includes eight orfs encompassing 40 kb and includes most of the genes predic ...	2003	12853152
plma, a new member of the gntr family, has plasmid maintenance functions in anabaena sp. strain pcc 7120.	the filamentous cyanobacterium anabaena (nostoc) sp. strain pcc 7120 maintains a genome that is divided into a 6.4-mb chromosome, three large plasmids of more that 100 kb, two medium-sized plasmids of 55 and 40 kb, and a 5.5-kb plasmid. plasmid copy number can be dynamic in some cyanobacterial species, and the genes that regulate this process have not been characterized. here we show that mutations in an open reading frame, all1076, reduce the numbers of copies per chromosome of several plasmids ...	2003	12867439
[the accumulation and degradation dynamics of cyanophycin in cyanobacteria grown in symbiotic associations with plant tissues and cells].	five different artificial associations of cyanobacterial cells with the cells or tissues of nightshade and rauwolfia were studied. the associations grown on nitrogen-containing media produced heterocysts. cyanobacterial cells in the associations retained their ability to take up bound nitrogen from the medium, to store it in the form of cyanophycin granules, and to use them in the process of symbiotic growth. the synthesis and degradation of cyanophycin granules in cyanobacterial cells were more ...	2003	12901011
raman spectroscopic detection of biomolecular markers from antarctic materials: evaluation for putative martian habitats.	the vital uv-protective and photosynthetic pigments of cyanobacteria and lichens (microbial symbioses) that dominate primary production in antarctic desert ecosystems auto-fluoresce at short-wavelengths. a long wavelength (1064 nm) near infra-red laser has been used for non-intrusive raman spectroscopic analysis of their ecologically significant compounds. there is now much interest in the construction of portable raman systems for the analysis of cyanobacterial and lichen communities in the fie ...	2003	12909141
commercial development of microalgal biotechnology: from the test tube to the marketplace.	while humans have taken limited advantage of natural populations of microalgae for centuries (nostoc in asia and spirulina in africa and north america for sustenance), it is only recently that we have come to realize the potential of microalgal biotechnology. microalgal biotechnology has the potential to produce a vast array of products including foodstuffs, industrial chemicals, compounds with therapeutic applications and bioremediation solutions from a virtually untapped source. from an indust ...	2003	12919832
lipid metabolism in cultured lichen photobionts with different phosphorus status.	lipid metabolism was studied in different photobiont species from lichens by following incorporation of radiolabel from [1-14c]acetate. in four algal photobionts, coccomyxa mucigena, c. peltigera variolosae, trebouxia aggregata, t. erici, polar lipids were mainly (73-90%) labelled while triacylglycerols were the most highly labelled non-polar lipid class. a rhamnose-containing lipid was found in two coccomyxa species, representing about 11% of the polar lipids of c. mucigena. all the major algal ...	2003	12946419
unusual water flux in the extracellular polysaccharide of the cyanobacterium nostoc commune.	the speed of water uptake by desiccated nostoc commune was found to depend upon the duration of desiccation. the rehydration of desiccated colonies led to marked, time-dependent changes in structure and ultrastructure and fluctuations in the composition of the transcriptome. physical evaporative water loss is an active process that was influenced by inhibitors of transcription and translation.	2003	12957961
biodiversity of algae and protozoa in a natural waste stabilization pond: a field study.	a field study was carried out on the biodiversity of protozoa and algae from a natural waste stabilization pond during november, 1996 to april, 1997. the raw waste and pond samples were analysed for physico-chemical and biological parameters. high dissolved oxygen (do) coinciding with phytoplankton peak was recorded. the algae--chlorella vulgaris, scenedesmus acuminatus, oscillatoria brevis and nostoc piscinale and protozoa--paramecium caudatum, acanthamoeba sp., bodo saltans and oikomonas termo ...	2003	12974463
[influence of light on the biological fixation of nitrogen by nostoc commune].		1952	12978729
necessity of boron for nostoc muscorum.		1952	13002436
studies on the photosynthetic reaction. i. the assimilation of acetate by nostoc muscorum.		1953	13084591
[energetic antibiotic properties of a soil alga; nostoc muscorum ag..].		1954	13172944
[the fine structure of the nostoc slime].		1954	13206292
toxicity of a rice field herbicide in some nitrogen-fixing algae.	the incorporation of diquat into cultures of nostoc muscorum and cylindrospermum sp. proved to be highly toxic. the range of various concentrations employed varies from 1 microgram/ml 15 micrograms/ml. relatively higher does (above 5 micrograms/ml) reduced the chlorophyll a content and a progressive decrease in algal growth and ultimately complete lysis of the cells was recorded with the increasing level of the herbicide. a concentration of 15 micrograms/ml has been found to be algicidal for bot ...	2002	13677067
the effect of light on this developmental cycle of nostoc muscorum, a filamentous blue-green alga.		1961	13759768
physiological and biochemical studies on nitrogen fixing blue-green algae. i. on the nature of cellular and extracellular nitrogenous substances formed by nostoc commune.		1962	13918955
physiological and biochemical studies on nitrogen fixation by blue-green algae. iii. the growth and nitrogen fixation of nostoc commune as influenced by culture conditions.		1963	13980209
the relationship of cellular differentiation to colonial morphogenesis of the blut-gree alga, nostoc muscorum a.		1964	14188771
amino acid composition and c-terminal residues of algal biliproteins.	1. r-phycoerythrin from ceramium rubrum and c-phycocyanin from nostoc muscorum have been obtained in purified form by fractional crystallization, followed by chromatography and gel-filtration. 2. the amino acid composition of both chromoproteins was determined; 85% of the total weight of both was recovered as amino acids. 3. alanine was identified as the only c-terminal amino acid of r-phycoerythrin, each molecule of which contained about 12 terminal groups. 4. serine was identified as the only ...	1965	14342224
the participation of filament anastomosis in the developmental cycle of nostoc muscorum, a blue-green alga.		1962	14463093
studies with cyanidium caldarium. i. the fine structure and systematic position of the organism.	the fine structure of cyanidium caldarium, as seen in thin sections of kmno(4)-fixed cells examined with the electron microscope, is described. this organism, whose taxonomic position among algae is undetermined, contains a single well defined chloroplast, a nucleus, and mitochondria. studies, with the electron microscope, of chlorella pyrenoidosa and nostoc are also reported. structural differences within cells of cyanidium, chlorella, and nostoc are discussed. it is concluded that if nostoc ca ...	1962	14472748
pcr-based identification of microcystin-producing genotypes of different cyanobacterial genera.	microcystins are harmful hepatotoxins produced by many, but not all strains of the cyanobacterial genera anabaena, microcystis, anabaena, planktothrix, and nostoc. waterbodies have to be monitored for the mass development of toxic cyanobacteria; however, because of the close genetic relationship of microcystin-producing and non-producing strains within a genus, identification of microcystin-producers by morphological criteria is not possible. the genomes of microcystin-producing cells contain mc ...	2003	14551674
slr2013 is a novel protein regulating functional assembly of photosystem ii in synechocystis sp. strain pcc 6803.	the synechocystis sp. strain pcc 6803, which has a t192h mutation in the d2 protein of photosystem ii, is an obligate photoheterotroph due to the lack of assembled photosystem ii complexes. a secondary mutant, rg2, has been selected that retains the t192h mutation but is able to grow photoautotrophically. restoration of photoautotrophic growth in this mutant was caused by early termination at position 294 in the slr2013 protein. the t192h mutant with truncated slr2013 forms fully functional phot ...	2003	14594835
anabaena sp. strain pcc 7120 hety gene influences heterocyst development.	the filamentous cyanobacterium anabaena (nostoc) sp. strain pcc 7120 responds to starvation for fixed nitrogen by producing a semiregular pattern of nitrogen-fixing cells called heterocysts. overexpression of the hety gene partially suppressed heterocyst formation, resulting in an abnormal heterocyst pattern. inactivation of hety increased the time required for heterocyst maturation and caused defects in heterocyst morphology. the 489-bp hety gene (alr2300), which is adjacent to pats (asl2301), ...	2003	14617665
the cyanobiont in an azolla fern is neither anabaena nor nostoc.	the cyanobacterial symbionts in the fern azolla have generally been ascribed to either the anabaena or nostoc genera. by using comparisons of the sequences of the phycocyanin intergenic spacer and a fragment of the 16s rrna, we found that the cyanobiont from an azolla belongs to neither of these genera.	2003	14659541
prokaryotic origins for the mitochondrial alternative oxidase and plastid terminal oxidase nuclear genes.	the mitochondrial alternative oxidase is a diiron carboxylate quinol oxidase (dox) found in plants and some fungi and protists, but not animals. the plastid terminal oxidase is distantly related to alternative oxidase and is most likely also a dox protein. database searches revealed that the alpha-proteobacterium novosphingobium aromaticivorans and the cyanobacteria nostoc sp. pcc7120, synechococcus sp. wh8102 and prochlorococcus marinus subsp. pastoris ccmp1378 each possess a dox homolog. each ...	2003	14675750
response of desert biological soil crusts to alterations in precipitation frequency.	biological soil crusts, a community of cyanobacteria, lichens, and mosses that live on the soil surface, occur in deserts throughout the world. they are a critical component of desert ecosystems, as they are important contributors to soil fertility and stability. future climate scenarios predict alteration of the timing and amount of precipitation in desert environments. because biological soil crust organisms are only metabolically active when wet, and as soil surfaces dry quickly in deserts du ...	2004	14689292
cloning, sequencing, and biochemical characterization of the nostocyclopeptide biosynthetic gene cluster: molecular basis for imine macrocyclization.	nostocyclopeptides a1 and a2 are novel cyclic heptapeptides produced by the terrestrial cyanobacterium nostoc sp. atcc53789 that possess a unique imino linkage in the macrocyclic ring. herein we report the cloning, sequencing, annotation, and biochemical analysis of the 33-kb nostocyclopeptide (ncp) biosynthetic gene cluster, which includes seven open reading frames predicted to be involved in the biosynthesis and transport of these natural products. the genetic architecture and domain organizat ...	2004	14697508
horizontal gene transfer of "prototype" nramp in bacteria.	eukaryotic nramp genes encode divalent metal ion permeases important for nutrition and resistance to microbial infection. bacterial homologs encode proton-dependent transporters of manganese (mnth), and other divalent metal ions. bacterial mnth were classified in three homology groups (a, b, c) and mnth c further subdivided in calpha, cbeta, cgamma. the proteins from c. tepidum (mnth b) and e. faecalis (mnth cbeta1, 2), divergent in sequence and hydropathy profile, conferred increased metal sens ...	2003	14708570
differentiation of nostoc flagelliforme and its neighboring species using fatty-acid profiling as a chemotaxonomic tool.	in this study, fatty-acid content and patterns were analyzed in order to distinguish nostoc flagelliforme, an edible terrestrial cyanobacterium, from other nostoc species and representatives typical of its close neighbors (genera anabaena, microcystis, and synechococcus). according to the kenyon-murata classification system, all the nostoc species were assigned to group ii due to the presence of c18:2n3 and c18:3n3, and the absence of c18:3n6. hierarchical cluster analysis was also employed to s ...	2003	14756530
diazotrophic community structure and function in two successional stages of biological soil crusts from the colorado plateau and chihuahuan desert.	the objective of this study was to characterize the community structure and activity of n2-fixing microorganisms in mature and poorly developed biological soil crusts from both the colorado plateau and chihuahuan desert. nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the colorado plateau site and chihuahuan desert site, respectively. analysis of nifh sequences by clone sequencing and the terminal restriction fragment length poly ...	2004	14766579
characterization of phytochelatin synthase-like protein encoded by alr0975 from a prokaryote, nostoc sp. pcc 7120.	phytochelatins (pcs) are well known as the heavy metal-detoxifying peptides in higher plants, eukaryotic algae, fungi, and nematode. in contrast, neither pcs nor pc synthase genes have ever been identified in any prokaryotes. the genome sequences for the cyanobacterium nostoc sp. pcc 7120 were recently completed and allowed us to identify a gene encoding a pc synthase-like protein, termed alr0975. the predicted product of alr0975 contains the conserved n-terminal domain but not the variable c-te ...	2004	14975765
cell differentiation and colony alteration of an edible terrestrial cyanobacterium nostoc flagelliforme, in liquid suspension cultures.	morphological characteristics of an edible terrestrial cyanobacterium nostoc flagelliforme in liquid suspension cultures under photoautotrophic conditions are presented. different cell forms alternated in a regular manner during the experimentation period (30 d). n. flagelliforme exhibited a very complex life cycle in terms of colony morphology, including mainly 4 different colony morphological forms, viz. hormogonia, filaments, seriate colonies and aseriate colonies. under laboratory conditions ...	2003	14976718
a dna adenine methyltransferase of escherichia coli that is cell cycle regulated and essential for viability.	dna sequence analysis revealed that the putative yhdj dna methyltransferase gene of escherichia coli is 55% identical to the nostoc sp. strain pcc7120 gene encoding dna methyltransferase avaiii, which methylates adenine in the recognition sequence, atgcat. the yhdj gene was cloned, and the enzyme was overexpressed and purified. methylation and restriction analysis showed that the dna methyltransferase methylates the first adenine in the sequence atgcat. this dna methylation was found to be regul ...	2004	15028690
evidence for multiple lateral transfers of the circadian clock cluster in filamentous heterocystic cyanobacteria nostocaceae.	cyanobacteria are the first prokaryotes reported to show circadian rhythmicity, which is regulated by a cluster of three genes: kaia, kaib, and kaic. phylogenetic analysis of the kaibc cluster in filamentous cyanobacteria of the family nostocaceae including nodularia spumigena and nostoc linckia from arubotaim cave, mt. sedom, israel, indicated that this cluster has experienced multiple lateral transfers. the transfers have occurred in different periods of the species' evolution. the data obtain ...	2004	15045489
role of cyanobacteria in the persistence of vibrio cholerae o139 in saline microcosms.	recently, a new strain of cholera, vibrio cholerae o139, has emerged as an epidemic strain, but there is little information about its environmental reservoir. the present investigation was aimed to determine the role of cyanobacteria in the persistence of v. cholerae o139 in microcosms. an environmental isolate of v. cholerae o139 and three cyanobacteria (anabaena sp., nostoc sp., and hapalosiphon sp.) were used in this study. survival of culturable v. cholerae o139 in microcosms was monitored u ...	2004	15052315
studies on phosphate uptake, accumulation and activity of alkaline phosphatase of nostoc muscorum under cd stress.		2004	15057710
gas exchange in the filamentous cyanobacterium nostoc punctiforme strain atcc 29133 and its hydrogenase-deficient mutant strain nhm5.	nostoc punctiforme atcc 29133 is a nitrogen-fixing, heterocystous cyanobacterium of symbiotic origin. during nitrogen fixation, it produces molecular hydrogen (h(2)), which is recaptured by an uptake hydrogenase. gas exchange in cultures of n. punctiforme atcc 29133 and its hydrogenase-free mutant strain nhm5 was studied. exchange of o(2), co(2), n(2), and h(2) was followed simultaneously with a mass spectrometer in cultures grown under nitrogen-fixing conditions. isotopic tracing was used to se ...	2004	15066806
comprehensive analysis system using liquid chromatography-mass spectrometry for the biosynthetic study of peptides produced by cyanobacteria.	microcystins are hepatotoxic heptapeptides and general tumor promoters produced by several species of the genera microcystis, anabaena, oscillatoria and nostoc. they are non-ribosomally synthesized via a mixed polyketide synthase/non-ribosomal peptide synthetase system called microcystin synthetase. we have carried out the detection, isolation and structural determination of non-toxic peptides produced together with microcystins by toxic cyanobacteria, which are classified into several groups on ...	2004	15072295
devr-devs is a bona fide two-component system of mycobacterium tuberculosis that is hypoxia-responsive in the absence of the dna-binding domain of devr.	two-component systems play a central role in the adaptation of pathogenic bacteria to the environment prevailing within host tissues. the genes encoding the response regulator devr (rv3133c/dosr) and the cytoplasmic portion (devs(201)) of the histidine kinase devs (rv3132c/doss), a putative two-component system of mycobacterium tuberculosis, were cloned and the protein products were overexpressed, purified and refolded as n-terminally his(6)-tagged proteins from escherichia coli. devs(201) under ...	2004	15073296
expression of cyanobacterial genes involved in heterocyst differentiation and dinitrogen fixation along a plant symbiosis development profile.	members of the cyanobiont genus nostoc, forming an endosymbiosis with members of the angiosperm genus gunnera, undergo a number of characteristic phenotypic changes during the development of the symbiosis, the genetic background of which is largely unknown. transcription patterns of genes related to heterocyst differentiation and dinitrogen fixation and corresponding protein profiles were examined, using reverse transcription-polymerase chain reaction and western blots, along a developmental (ap ...	2004	15077676
assessment of the effect of the toxicity of a textile dye on nostoc muscorum isu, a diazotrophic cyanobacterium.	the impact of graded concentrations (5, 10, 15 and 20 mg dm(-3) of acid mordant metomega chrome orange gl, a common dye used in woollen, carpet and textile industries, was studied on protein and pigment content and photosynthetic oxygen evolution in a diazotrophic cyanobacterium nostoc muscorum. the lower concentration of 5 mg dm(-3) showed a negligible effect on protein and pigment content and photosynthetic oxygen evolution, whereas at higher concentrations a drastic decrease in the above para ...	1994	15091720
the effect of crude oil and oil spill chemicals on nitrogen fixation in the cyanobacteria nostoc sp.	the effects of crude oil and three oil spill dispersants (corexit 9600, 9550 and 7664) on nitrogenase activity in the cyanobacteria nostoc sp. were examined. the addition of oil to nostoc sp. cultures resulted in a catastrophic decline in nitrogenase activity with activity ceasing 7 h after treatment. the addition of a dispersant with the oil did not ameliorate this effect. cultures exposed to high concentrations of dispersants showed lower rates on nitrogenase activity than untreated cultures. ...	1988	15092640
ecosystems on ice: the microbial ecology of markham ice shelf in the high arctic.	microbial communities occur throughout the cryosphere in a diverse range of ice-dominated habitats including snow, sea ice, glaciers, permafrost, and ice clouds. in each of these environments, organisms must be capable of surviving freeze-thaw cycles, persistent low temperatures for growth, extremes of solar radiation, and prolonged dormancy. these constraints may have been especially important during global cooling events in the past, including the precambrian glaciations. one analogue of these ...	2004	15094087
a preliminary investigation of the nostoc punctiforme proteome.	nostoc punctiforme atcc 29133 is a filamentous terrestrial cyanobacterium (prokaryote) that expresses several different phenotypes in response to environmental cues. when grown in nitrogen-deficient media the most abundant proteins in addition to phycobiliproteins were superoxide dismutase, atp synthase, and peptidyl-prolyl cis-trans isomerases. a methylated peptide from an akinete marker protein was also identified, suggesting that methylation could potentially play a regulatory role through si ...	2004	15094385
generation of reactive oxygen species undergoing redox cycle of nostocine a: a cytotoxic violet pigment produced by freshwater cyanobacterium nostoc spongiaeforme.	nostocine a (1) is an extracellular cytotoxic violet pigment produced by the freshwater cyanobacterium, nostoc spongiaeforme tistr 8169. treatment with 1 was found to accelerate the generation of reactive oxygen species (ros) in the green alga, chlamydomonas reinhardtii, in the light. in vitro analysis revealed that 1 specifically eliminated superoxide radical anion (o(2)(-)) among several ros tested. during the course of the reaction, oxygen (o(2)) was simultaneously synthesized and the o(2) sy ...	2004	15099903
[phagoresistance of filamentous cyanobacteria clones].	the paper deals with formation regularities of phagoresistant clones of cyanobacteria in two productive virus-cell systems: heterocyst cyanobacterium nostoc linckia--cyanophage n-2, and mutant in heterocysts strain of anabaena variabilis--cyanophage a-1. frequency of spontaneous formation of phagoresistant clones of cyanobacterium n. linckia varies within 1.0-8.0 x 10(-6) per a cell, a. variabilis--5.0 x 10(-6)-7.0 x 10(-7) per cell. all the studied phagoresistant clones of n. linckia have ident ...	2004	15104055
cross talk between devs sensor kinase homologue, rv2027c, and devr response regulator of mycobacterium tuberculosis.	rv2027c is a putative orphan histidine sensor kinase that bears strong homology to devs of the hypoxia-responsive devr-devs two-component system in m. tuberculosis. the cytosolic c-terminal domain of rv2027c protein (rv2027c(194)) was overexpressed in e. coli and biochemically characterized. rv2027c(194) underwent autophosphorylation at a conserved his(392) residue and engaged in phosphotransfer with devr response regulator. the rates of autophosphorylation and the stabilities of the phosphoryla ...	2004	15135056
sensor domain of the mycobacterium tuberculosis receptor ser/thr protein kinase, pknd, forms a highly symmetric beta propeller.	diverse pathogenic bacteria produce transmembrane receptor ser/thr protein kinases (stpks), but little is known about the signals mediated by these "eukaryotic-like" proteins. to explore the basis for signaling in the bacterial stpk receptor family, we determined the structure of the sensor domain of mycobacterium tuberculosis pknd. in two crystal forms, the pknd sensor domain forms a rigid, six-bladed beta-propeller with a flexible tether to the transmembrane domain. the pknd sensor domain is t ...	2004	15136047
impact of nitrophenols on the photosynthetic electron transport chain and atp content in nostoc muscorum and chlorella vulgaris.	concentration-dependent inhibition of the photosynthetic electron transport chain (photosystem i (ps i), photosystem ii (ps ii) and whole chain reaction) and atp content was observed in nostoc muscorum and chlorella vulgaris grown with o-nitrophenol, m-nitrophenol, or 2,4-dinitrophenol. although the extents of inhibition of the photosynthetic electron transport chain in both organisms were similar, ps ii was more sensitive than ps i and whole chain reaction to the nitrophenols. depletion of the ...	2004	15157580
light-induced intramolecular charge movements in microbial rhodopsins in intact e. coli cells.	microbial rhodopsins undergo cyclic photochemical reactions (photocycles) in which proton transfers and conformational changes result in charge displacements during transitions between photocycle intermediates. we report a new photoelectric method to monitor charge movements during rhodopsin photocycling with fast kinetic resolution in suspensions of intact e. coli cells. the method monitors electrical currents resulting from asymmetric photoexcitation of microbial rhodopsins by a unilateral las ...	2004	15170484
evaluation of nostoc strain atcc 53789 as a potential source of natural pesticides.	the cyanobacterium nostoc strain atcc 53789, a known cryptophycin producer, was tested for its potential as a source of natural pesticides. the antibacterial, antifungal, insecticidal, nematocidal, and cytotoxic activities of methanolic extracts of the cyanobacterium were evaluated. among the target organisms, nine fungi (armillaria sp., fusarium oxysporum f. sp. melonis, penicillium expansum, phytophthora cambivora, p. cinnamomi, rhizoctonia solani, rosellinia, sp., sclerotinia sclerotiorum, an ...	2004	15184126
comparative toxicological evaluation of untreated and treated tannery effluent with nostoc muscorum l. (algal assay) and microtox bioassay.	the relative sensitivity of tannery effluent before and after treatment was compared by employing nostoc muscorum and microtox assay in laboratory. the effect on chlorophyll, protein and biomass content of nostoc muscorum was studied with the luminescent property inhibition of photobacterium phosphorium and compared with algal bioassay. the results of microtox assay after 5, 15 and 30 min of exposure were compared with data obtained from algal bioassay. it was observed that the luminescent prope ...	2004	15195832
combined directed ortho and remote metalation-cross-coupling strategies. general method for benzo[a]carbazoles and the synthesis of an unnamed indolo[2,3-a]carbazole alkaloid.	[reaction: see text] an efficient route to benzo[a]carbazoles via a metalation-cross-coupling sequence has been demonstrated and its application to the synthesis of the antitumor and antiviral alkaloid 6-cyano-5-methoxy-12-methylindolo[2,3-a]carbazole has been achieved.	2004	15228262
novel classes of mutants of the cyanobacterium nostoc muscorum showing absolute requirement of cs1 or rb1 for diazotrophy.		2004	15248149
phylogenetic analysis of symbiotic and free-living cyanobacterial cultures using dna amplification fingerprinting.	dna amplification fingerprinting (daf) of 17 cyanobacterial isolates belonging to symbiotic and free-living forms of 6 different genera was done. the dendrogram analysis of 17 cyanobacterial cultures revealed three major clusters. all westiellopsis cultures formed the first major cluster and their nucleotide relatedness ranged between 71-93%. in the second major cluster, the symbiotic cyanobacterium anabaena sp dominated and all anabaena cultures showed 60-75% similarity with each other. nostoc ...	2003	15248486
cloning of two carotenoid ketolase genes from nostoc punctiforme for the heterologous production of canthaxanthin and astaxanthin.	for the heterologous synthesis of keto-carotenoids such as astaxanthin, two carotenoid ketolase genes crtw38 and crtw148, were cloned from the cyanobacterium, nostoc punctiforme pcc 73102 and functionally characterized. upon expression in escherichia coli, both genes mediated the conversion of beta-carotene to canthaxanthin. however in a zeaxanthin-producing e. coli, only the gene product of crtw148 introduced 4-keto groups into the 3,3'-dihydroxy carotenoid zeaxanthin yielding astaxanthin. the ...	2004	15269553
deactivation of photosynthetic activities is triggered by loss of a small amount of water in a desiccation-tolerant cyanobacterium, nostoc commune.	changes in photosynthetic activities under hypertonic conditions were studied in a terrestrial, highly desiccation-tolerant cyanobacterium, nostoc commune, and in some desiccation-sensitive cyanobacteria. the amounts of water sustained in the colony matrix outside the n. commune cells and the cellular solute concentration were estimated by measuring the water potential, and the solute concentration was supposed to correspond to around 0.22 m sorbitol. incubation of the colonies in 0.8 m sorbitol ...	2004	15295070
a mechanism for slow release of biomagnified cyanobacterial neurotoxins and neurodegenerative disease in guam.	as root symbionts of cycad trees, cyanobacteria of the genus nostoc produce beta-methylamino-l-alanine (bmaa), a neurotoxic nonprotein amino acid. the biomagnification of bmaa through the guam ecosystem fits a classic triangle of increasing concentrations of toxic compounds up the food chain. however, because bmaa is polar and nonlipophilic, a mechanism for its biomagnification through increasing trophic levels has been unclear. we report that bmaa occurs not only as a free amino acid in the gua ...	2004	15295100
the iron superoxide dismutase from the filamentous cyanobacterium nostoc pcc 7120. localization, overexpression, and biochemical characterization.	the nitrogen-fixing filamentous cyanobacterium nostoc pcc 7120 (formerly named anabaena pcc 7120) possesses two genes for superoxide dismutase, a unique membrane-associated manganese superoxide dismutase (mnsod) and a soluble iron superoxide dismutase (fesod). a phylogenetic analysis of fesods shows that cyanobacterial enzymes form a well separated cluster with filamentous species found in one subcluster and unicellular species in the other. activity staining, inhibition patterns, and immunogold ...	2004	15302891
biolingua: a programmable knowledge environment for biologists.	biolingua is an interactive, web-based programming environment that enables biologists to analyze biological systems by combining knowledge and data through direct end-user programming. biolingua embeds a mature symbolic programming language in a frame-based knowledge environment, integrating genomic and pathway knowledge about a class of similar organisms. the biolingua language provides interfaces to numerous state-of-the-art bioinformatic tools, making these available as an integrated package ...	2005	15308539
isolation and structure determination of cryptophycins 38, 326, and 327 from the terrestrial cyanobacterium nostoc sp. gsv 224.	cryptophycin-38 (2), -326 (3), and -327 (4) are three new trace constituents of the terrestrial cyanobacterium nostoc sp. gsv 224. cryptophycin-38 is a stereoisomer of cryptophycin-1 (1) and to date is the only naturally occurring analogue that possesses a s,s epoxide group in unit a. cryptophycin-327 is a geometric isomer that differs from 1 in having a cis delta(2)-double bond in unit a. cryptophycin-326 is related to cryptophycin-21, but has two chlorines ortho to the methoxy group in unit b. ...	2004	15332864
microbial diversity of extant stromatolites in the hypersaline marine environment of shark bay, australia.	stromatolites have been present on earth, at various levels of distribution and diversity, for more than 3 billion years. today, the best examples of stromatolites forming in hypersaline marine environments are in hamelin pool at shark bay, western australia. despite their evolutionary significance, little is known about their associated microbial communities. using a polyphasic approach of culture-dependent and culture-independent methods, we report the discovery of a wide range of microorganis ...	2004	15344935
decomposition of microcystin-lr, microcystin-rr, and microcystin-yr in water samples submitted to in vitro dissolution tests.	the presence of cyanobacterial toxins (microcystins) in waters and food increases the risk of toxicity to animal and human health. these toxins can degrade in the human gastrointestinal tract before they are absorbed. to evaluate this possible degradation, water samples spiked with known concentrations of microcystins mc-lr, mc-rr, and mc-yr, which are the toxins most commonly produced by such toxic cyanobacteria as microcystis aeruginosa, oscillatoria spp., and nostoc spp., were submitted to a ...	2004	15366845
construction and use of gfp reporter vectors for analysis of cell-type-specific gene expression in nostoc punctiforme.	two transcriptional reporter shuttle vectors were constructed for the filamentous cyanobacterium nostoc punctiforme using the green fluorescence protein (gfp) reporter. both the ampicillin- and kanamycin-resistant versions of the plasmid allow promoters to be directionally cloned into a multiple cloning site preceding a promoterless gfp gene using an escherichia coli host. the ability of the self-replicating shuttle plasmids to report cell-type-specific gene expression in n. punctiforme was test ...	2004	15369854
molecular evolution of pas domain-containing proteins of filamentous cyanobacteria through domain shuffling and domain duplication.	when the entire genome of a filamentous heterocyst-forming n2-fixing cyanobacterium, anabaena sp. pcc 7120 (anabaena) was determined in 2001, a large number of pas domains were detected in signal-transducing proteins. the draft genome sequence is also available for the cyanobacterium, nostoc punctiforme strain atcc 29133 (nostoc), that is closely related to anabaena. in this study, we extracted all pas domains from the nostoc genome sequence and analyzed them together with those of anabaena. clu ...	2004	15449540
[effect of cadmium on the absorption and excitation energy transfer in cyanobacterium nostoc muscorum].	the absorption and energy transfer between pigments in nostoc muscorum by the action of 10(-4) m cd2+, when the cyanobacterium remains viable, and in the presence of 10(-3) m cd2+, which causes the death of cells during 3-4 weeks of incubation, were studied. a comparative study by the methods of absorption and fluorescence spectrophotometry at 295 and 77 k, including derivative spectroscopy and deconvolution of emission spectra into a number of gaussian components, showed that, in the presence o ...	2004	15458254
discovery of rare and highly toxic microcystins from lichen-associated cyanobacterium nostoc sp. strain io-102-i.	the production of hepatotoxic cyclic heptapeptides, microcystins, is almost exclusively reported from planktonic cyanobacteria. here we show that a terrestrial cyanobacterium nostoc sp. strain io-102-i isolated from a lichen association produces six different microcystins. microcystins were identified with liquid chromatography-uv mass spectrometry by their retention times, uv spectra, mass fragmentation, and comparison to microcystins from the aquatic nostoc sp. strain 152. the dominant microcy ...	2004	15466511
[bioinformatics studies on photosynthetic system genes in cyanobacteria and chloroplasts].	this study compared homology of base sequences in genes encoding photosynthetic system proteins of cyanobacteria (synechocystics sp. pcc6803, nostoc sp. pcc7120) with these of chloroplasts (from marchantia polymorpha, nicotiana tobacum, oryza sativ, euglena gracilis, pinus thunbergii, zea mays, odentella sinesis, cyanophora paradoxa, porphyra purpurea and arabidopsis thaliana) by blast method. while the gene sequence of synechocystics sp. pcc6803 was considered as the criterion (100%) the homolo ...	2004	15490883
identification and analysis of a siderophore biosynthetic gene cluster from agrobacterium tumefaciens c58.	using the complete genome sequence from agrobacterium tumefaciens c58, the authors identified a secondary metabolite gene cluster that encodes the biosynthesis of a metabolite with siderophore activity. support for this conclusion came from genetic and regulatory analysis of the gene cluster, along with the purification of a metabolite from a. tumefaciens c58 with iron-chelating activity. genetic analysis of mutant strains disrupted in this gene cluster showed that these strains grew more slowly ...	2004	15528670
comparison of light and dark nitrogenase activity in selected soil cyanobacteria.	frequency of heterocytes and nitrogenase activity (na) under light and dark cultivation conditions was determined in 12 cyanobacterial strains isolated from various soil habitats. in spite of a high variability, significant differences in na among the strains were found in response of light and dark cultivation. relatively high na (9.9-15.3 micromol/h c2h4 per g fresh mass) under light conditions and basal na after 12 h of dark cultivation were detected in anabaena, nodularia, tolypothrix, and 1 ...	2004	15530010
phylogeny of symbiotic cyanobacteria within the genus nostoc based on 16s rdna sequence analyses.	a phylogenetic analysis of selected symbiotic nostoc strain sequences and available database 16s rdna sequences of both symbiotic and free-living cyanobacteria was carried out using maximum likelihood and bayesian inference techniques. most of the symbiotic strains fell into well separated clades. one clade consisted of a mixture of symbiotic and free-living isolates. this clade includes nostoc sp. strain pcc 73102, the reference strain proposed for nostoc punctiforme. a separate symbiotic clade ...	2005	15549268
cyanobacteria in antarctica: ecology, physiology and cold adaptation.	cyanobacterial species composition of fresh water and terrestrial ecosystems and chemical environment of water in schirmacher oasis in continental antarctica was investigated. over 35 species of cyanobacteria were recorded. diazotrophic species both heterocystous and unicellular contributed more than half to the count except in lake ecosystem. the species composition varied among the fresh water as well as terrestrial ecosystems. the physico-chemical analyses of water revealed its poor nurient c ...	2004	15559974
a cyanobacterial protein with similarity to phytochelatin synthases catalyzes the conversion of glutathione to gamma-glutamylcysteine and lacks phytochelatin synthase activity.	phytochelatins are glutathione-derived, non-translationally synthesized peptides essential for cadmium and arsenic detoxification in plant, fungal and nematode model systems. recent sequencing programs have revealed the existence of phytochelatin synthase-related genes in a wide range of organisms that have not been reported yet to produce phytochelatins. among those are several cyanobacteria. we have studied one of the encoded proteins (alr0975 from nostoc sp. strain pcc 7120) and demonstrate h ...	2004	15561184
bacterial life and dinitrogen fixation at a gypsum rock.	the organisms of a bluish-green layer beneath the shards of a gypsum rock were characterized by molecular techniques. the cyanobacterial consortium consisted almost exclusively of chroococcidiopsis spp. the organisms of the shards expressed nitrogenase activity (c2h2 reduction) aerobically and in light. after a prolonged period of drought at the rock, the cells were inactive, but they resumed nitrogenase activity 2 to 3 days after the addition of water. in a suspension culture of chroococcidiops ...	2004	15574902
development of a universal microarray based on the ligation detection reaction and 16s rrna gene polymorphism to target diversity of cyanobacteria.	the cyanobacteria are photosynthetic prokaryotes of significant ecological and biotechnological interest, since they strongly contribute to primary production and are a rich source of bioactive compounds. in eutrophic fresh and brackish waters, their mass occurrences (water blooms) are often toxic and constitute a high potential risk for human health. therefore, rapid and reliable identification of cyanobacterial species in complex environmental samples is important. here we describe the develop ...	2004	15574913
biotransformation of hydrocortisone by a natural isolate of nostoc muscorum.	hydrocortisone was converted in the culture of an isolated strain of the cyanobacterium nostoc muscorum ptcc 1636 into some androstane and pregnane derivatives. the microorganism was, isolated during a screening program from soil samples collected from paddy fields of north of iran. the bioproducts obtained were purified using chromatographic methods and identified as 11beta-hydroxytestosterone, 11beta-hydroxyandrost-4-en-3,17-dione and 11beta,17alpha,20beta,21-tetrahydroxypregn-4-en-3-one on th ...	2004	15587704
first documented cure of a suggestive exogenous reinfection in polymyositis with same but multidrug resistant m. tuberculosis.	mdr mycobacterium tuberculosis is the major cause of treatment failure in tuberculosis patients, especially in immunosuppressed. we described a young polymyositis patient on immunosuppressive therapy who was started with antituberculosis therapy as a susceptible strain of m. tuberculosis was isolated from a single cutaneous abscess in his neck and from regional lymph nodes.	2004	15617569
reconstitution of phycobilisome core-membrane linker, lcm, by autocatalytic chromophore binding to apce.	the core-membrane linker, lcm, connects functionally the extramembraneous light-harvesting complex of cyanobacteria, the phycobilisome, to the chlorophyll-containing core-complexes in the photosynthetic membrane. genes coding for the apoprotein, apce, from nostoc sp. pcc 7120 and for a c-terminally truncated fragment apce(1-240) containing the chromophore binding cysteine-195 were overexpressed in escherichia coli. both bind covalently phycocyanobilin (pcb) in an autocatalytic reaction, in the p ...	2005	15620367