Publications

induction of mycosporine-like amino acids (maas) in cyanobacteria by solar ultraviolet-b radiation.	three filamentous and heterocystous n(2)-fixing cyanobacteria, anabaena sp., nostoc commune and scytonema sp. were tested for the presence of ultraviolet-absorbing mycosporine-like amino acids (maas) and their induction by solar ultraviolet-b (uv-b) radiation. high performance liquid chromatographic (hplc) studies revealed the presence of only one type of maas in all three cyanobacteria, that was identified as shinorine, a bisubstituted maa containing both glycine and serine groups having an abs ...	2001	11470569
cryptophycins: a novel class of potent antimitotic antitumor depsipeptides.	the antitumor cryptophycins are synthetic derivatives of the desipeptide cryptophycins isolated from the cyanobacterium nostoc sp. cryptophycin 52 that is currently in clinical trial in solid tumors, is prepared by total synthesis of four key fragments that are coupled to form the final product. the mechanism of anticancer activity of the cryptophycins has been associated with their destabilization of microtubules and with their induction of bcl-2 phosphorylation leading to apoptosis. the crypto ...	2001	11472266
the role of papillae during the infection process in the gunnera-nostoc symbiosis.	gunnera manicata l. glands consist of up to nine separate papillae. surgical removal of papillae showed that more than two papillae were needed for successful infection with nostoc. infection occurs only in the enclosed space between adjacent papillae. dividing gunnera cells in the enclosed space are the sites of infection.	2001	11479387
characterization by genotypic methods of symbiotic nostoc strains isolated from five species of gunnera.	the genetic diversity of ten symbiotic nostoc strains isolated from different gunnera species was investigated. the strains were analyzed using molecular methods with different taxonomic resolutions, including restriction fragment length polymorphisms (rflp) of the pcr-amplified 16s ribosomal gene and the 16s-23s internal transcribed spacer (its) region combined with computer-assisted analyses. the functional gene hetr, assigned to heterocyst differentiation, was used for denaturing gradient gel ...	2001	11511868
genetic diversity of nostoc symbionts endophytically associated with two bryophyte species.	the diversity of the endophytic nostoc symbionts of two thalloid bryophytes, the hornwort anthoceros fusiformis and the liverwort blasia pusilla, was examined using the trna(leu) (uaa) intron sequence as a marker. the results confirmed that many different nostoc strains are involved in both associations under natural conditions in the field. the level of nostoc diversity within individual bryophyte thalli varied, but single dna fragments were consistently amplified from individual symbiotic colo ...	2001	11526056
[microbiota of the orchid rhizoplane].	six bacterial strains isolated from the underground roots of the terrestrial orchid calanthe vestita var. rubrooculata were found to belong to the genera arthrobacter, bacillus, mycobacterium, and pseudomonas. strains isolated from the aerial roots of the epiphytic orchid dendrobium moschatum were classified into the genera bacillus, curtobacterium, flavobacterium, nocardia, pseudomonas, rhodococcus, and xanthomonas. the rhizoplane of the terrestrial orchid was also populated by cyanobacteria of ...	2001	11558285
cyanobacteria in uruguayan rice fields: diversity, nitrogen fixing ability and tolerance to herbicides and combined nitrogen.	it has been established that cyanobacteria play a vital role in the maintenance of flooded rice field fertility. to evaluate the potential use of nitrogen-fixing cyanobacteria as a natural biofertilizer for rice in uruguay, the diversity, abundance and nitrogen fixing ability of these microorganisms were studied in the field and in the laboratory. the effect of urea fertilization on population density and diversity of heterocystous cyanobacteria was determined on a 3-year assay. the highest numb ...	2001	11566382
form species nostoc commune (cyanobacteria).	the form species concept for the cyanobacteria was evaluated using a comprehensive set of nostoc samples that were collected during the past two centuries, from all continents, including regions from the tropics to the poles. phylogenies were constructed based upon the conserved regions of trnaleu (uaa) group i intron dna sequences. thirty-four forms contained a trnaleu (uaa) intron of 284 nt. these 284-nt introns contained 200 nt of conserved sequence that, in most cases, shared 100% sequence i ...	2001	11594617
cellulose in cyanobacteria. origin of vascular plant cellulose synthase?	although cellulose biosynthesis among the cyanobacteria has been suggested previously, we present the first conclusive evidence, to our knowledge, of the presence of cellulose in these organisms. based on the results of x-ray diffraction, electron microscopy of microfibrils, and cellobiohydrolase i-gold labeling, we report the occurrence of cellulose biosynthesis in nine species representing three of the five sections of cyanobacteria. sequence analysis of the genomes of four cyanobacteria revea ...	2001	11598227
cloning, characterization, and functional expression in escherichia coli of argh encoding argininosuccinate lyase in the cyanobacterium nostoc sp. strain pcc 73102.	a gene argh, encoding argininosuccinate lyase (asl), has been cloned from a cosmid library of the filamentous cyanobacterium nostoc sp. strain pcc 73102. the argh open reading frame encodes a protein comprised of 461 amino acids with a calculated molecular mass of 51,349 da. protein sequence comparisons reveal significant similarities of the nostoc pcc 73102 asl to related proteins from other organisms. in an escherichia coli delta argh strain, the nostoc pcc 73102 asl expressed from a recombina ...	2001	11683360
a family of putative kir potassium channels in prokaryotes.	prior to this report, members of the inward rectifier family, or kir, have been found only in eukaryotes. like most k+ channels, the pore-forming part of the protein is formed by four identical, or closely related, subunits. each subunit contains a transmembrane m1-p-m2 motif that is followed by a relatively large c-terminus region unique to kir's.	2001	11806753
genome evolution of the cyanobacterium nostoc linckia under sharp microclimatic divergence at "evolution canyon," israel.	we describe the genomic dna diversity and divergence of the cyanobacterium nostoc linckia from "evolution canyon," a microsite consisting of ecologically contrasting slopes, south-facing slope (sfs) and north-facing slope (nfs), at lower nahal oren, mt. carmel, israel. the opposing slopes share their limestone lithology but vary greatly in their ecology, primarily because of different levels of solar radiation (which is six times higher on the sfs than on the nfs). the warm and xeric sfs display ...	2001	12024256
an overview of the genome of nostoc punctiforme, a multicellular, symbiotic cyanobacterium.	nostoc punctiforme is a filamentous cyanobacterium with extensive phenotypic characteristics and a relatively large genome, approaching 10 mb. the phenotypic characteristics include a photoautotrophic, diazotrophic mode of growth, but n. punctiforme is also facultatively heterotrophic; its vegetative cells have multiple developmental alternatives, including terminal differentiation into nitrogen-fixing heterocysts and transient differentiation into spore-like akinetes or motile filaments called ...	2001	16228364
evidence for production of the phytohormone indole-3-acetic acid by cyanobacteria.	the ability of cyanobacteria to produce the phytohormone indole-3-acetic acid (iaa) was demonstrated. a colorimetric (salkowski) screening of 34 free-living and symbiotically competent cyanobacteria, that represent all morphotypes from the unicellular to the highly differentiated, showed that auxin-like compounds were released by about 38% of the free-living as compared to 83% of the symbiotic isolates. the endogenous accumulation and release of iaa were confirmed immunologically (elisa) using a ...	2002	12029472
the cyanobacterial trna(leu) (uaa) intron: evolutionary patterns in a genetic marker.	cyanobacterial trna(leu) (uaa) intron sequences from natural populations of nostoc and other cyanobacteria were compared. variation between the different introns was not randomly distributed but strongly restricted by the secondary and tertiary structure of the intron. although all nostoc sequences examined shared high similarity, differences were observed in one stem-loop. this stem-loop could be divided into two classes, both built up from two base pairing heptanucleotide repeats. size variati ...	2002	12032241
cellular fatty acids as chemotaxonomic markers of the genera anabaena, aphanizomenon, microcystis, nostoc and planktothrix (cyanobacteria).	the cellular fatty acid content of 22 cyanobacterial strains belonging to the genera anabaena, aphanizomenon, calothrix, cylindrospermum, nostoc, microcystis and planktothrix were analysed. the identities of the major peaks were confirmed by ms. correspondence analysis of the data revealed three distinct groups formed by the microcystis strains, the nostoc/planktothrix strains and the anabaena/aphanizomenon/cylindrospermum strains. the calothrix strain did not cluster with the other heterocystou ...	2002	12054217
[participation of extracellular polysaccharides in detoxication of cadmium ions by cyanobacteria nostoc muscorum].	using the methods of absorption and fluorescence spectroscopy, histochemistry and micrography, the influence of cadmium in different concentrations on the exudation of exopolysaccharides by nostoc muscorum was studied to elucidate the possibility of distance detoxication of cadmium ions by the cyanobacterium with the participation of its exometabolites. the toxic action of cd was controlled by changes in biomass, trichomes morphology, and the photosynthetic apparatus of the cyanobacterium. the c ...	2002	12068610
isolation and characterization of a chlorate-resistant mutant (clo- r) of the symbiotic cyanobacterium nostoc anth: heterocyst formation and n(2)-fixation in the presence of nitrate, and evidence for separate nitrate and nitrite transport systems.	nostoc anth is a filamentous, heterocystous cyanobacterium capable of n(2)-fixation in the absence of combined nitrogen. a chlorate-resistant mutant (clo- r) of nostoc anth was isolated that differentiates heterocysts and fixes n(2) in the presence of nitrate, but not in the presence of nitrite or ammonium. the mutant lacks nitrate uptake and thereby also lacks induction of nitrate reductase activity by nitrate. however, this mutant is able to transport and assimilate nitrite, indicating that th ...	2002	12070686
cloning, overexpression, purification, and matrix-assisted refolding of devs (rv 3132c) histidine protein kinase of mycobacterium tuberculosis.	the devr-devs (rv 3133c-rv 3132c) two-component system of mycobacterium tuberculosis was identified in our laboratory by rna subtractive hybridization. this genetic system was predicted to encode a response regulator and histidine protein kinase, respectively. the putative histidine kinase protein devs was overexpressed to high levels in escherichia coli as a fusion protein with a hexahistidine tag, his(6)-devs201, in the form of inclusion bodies. here we report a "redox-based" method of matrix- ...	2002	12071717
molecular analysis of the dormancy response in mycobacterium smegmatis: expression analysis of genes encoding the devr-devs two-component system, rv3134c and chaperone alpha-crystallin homologues.	mycobacteria adapt to a decrease in oxygen tension by entry into a non-replicative persistent phase. it was shown earlier that the two-component system, devr-devs, was induced in mycobacterium tuberculosis and mycobacterium bovis bcg cultures during hypoxia, suggesting that it may play a regulatory role in their adaptation to oxygen limitation. the presence of a homologous genetic system in mycobacterium smegmatis was predicted by scanning its unfinished genome sequence with devr and devs genes ...	2002	12076818
genetic diversity of nostoc microsymbionts from gunnera tinctoria revealed by pcr-strr fingerprinting.	the cyanobacteria belonging to the genus nostoc fix atmospheric nitrogen, both as free-living organisms and in symbiotic associations with a wide range of hosts, including bryophytes, gymnosperms (cycads), the small water fern azolla (pteridophyte), the angiosperm genus gunnera, and fungi (lichens). the gunnera-nostoc symbiosis is the only one that involves a flowering plant. in chile, 12 species of gunnera have been described with a broad distribution in the temperate region. we examined the ge ...	2002	12087423
structures of the complexes of a potent anti-hiv protein cyanovirin-n and high mannose oligosaccharides.	the development of anti-human immunodeficiency virus (hiv) microbicides for either topical or ex vivo use is of considerable interest, mainly due to the difficulties in creating a vaccine that would be active against multiple clades of hiv. cyanovirin-n (cv-n), an 11-kda protein from the cyanobacterium (blue-green algae) nostoc ellipsosporum with potent virucidal activity, was identified in the search for such antiviral agents. the binding of cv-n to the heavily glycosylated hiv envelope protein ...	2002	12110688
molecular differentiation of the heterocystous cyanobacteria, nostoc and anabaena, based on complete nifd sequences.	the segregation of nostoc and anabaena into separate genera has been debated for some time. the nitrogen fixation gene nifd was completely sequenced from representatives of these genera and analyzed phylogenetically, by using the representatives of other genera of the heterocystous cyanobacteria as outgroups. we were clearly able to differentiate between nostoc and anabaena in all analyses used. our data suggest that nostoc and anabaena should remain as separate genera.	2002	12177735
biochemical characterization of a membrane-bound manganese-containing superoxide dismutase from the cyanobacterium anabaena pcc 7120.	the filamentous cyanobacterium anabaena pcc 7120 (now renamed nostoc pcc 7120) possesses two genes for superoxide dismutase (sod). one is an iron-containing (fesod) whereas the other is a manganese-containing superoxide dismutase (mnsod). localization experiments and analysis of the sequence showed that the fesod is cytosolic, whereas the mnsod is a membrane-bound homodimeric protein containing one transmembrane helix, a spacer region, and a soluble catalytic domain. it is localized in both cyto ...	2002	12215453
synergistic effect of deoxyanthocyanins from symbiotic fern azolla spp. on hrma gene induction in the cyanobacterium nostoc punctiforme.	the hrma gene of the n2-fixing cyanobacterium nostoc punctiforme functions in repressing the formation of transitory motile filaments, termed hormogonia, by plant-associated vegetative filaments. here, we report that anthocyanins can contribute to induction of hrma expression. aqueous extract from fronds of the fern azolla pinnata, a host of symbiotic nostoc spp., was found to be a potent inducer of hrma-luxab in n. punctiforme strain ucd 328. the hrma-luxab inducing activities of a. pinnata, as ...	2002	12236594
paenibacillus glycanilyticus sp. nov., a novel species that degrades heteropolysaccharide produced by the cyanobacterium nostoc commune.	a novel bacterial strain, ds-1t, was isolated that degrades heteropolysaccharide produced by the cyanobacterium nostoc commune. the isolate was identified by a combination of phenotypic characterization, cellular fatty acid analysis, dna base composition, dna-dna hybridization and 165 rrna gene sequence analysis. phylogenetic analysis placed strain ds-1t within the paenibacillus cluster on a phylogenetic tree and the phenotypic characteristics of this strain appear to be similar to those of paen ...	2002	12361272
analysis of the hli gene family in marine and freshwater cyanobacteria.	certain cyanobacteria thrive in natural habitats in which light intensities can reach 2000 micromol photon m(-2) s(-1) and nutrient levels are extremely low. recently, a family of genes designated hli was demonstrated to be important for survival of cyanobacteria during exposure to high light. in this study we have identified members of the hli gene family in seven cyanobacterial genomes, including those of a marine cyanobacterium adapted to high-light growth in surface waters of the open ocean ...	2002	12399037
quantifying nitrogen-fixation in feather moss carpets of boreal forests.	biological nitrogen (n) fixation is the primary source of n within natural ecosystems, yet the origin of boreal forest n has remained elusive. the boreal forests of eurasia and north america lack any significant, widespread symbiotic n-fixing plants. with the exception of scattered stands of alder in early primary successional forests, n-fixation in boreal forests is considered to be extremely limited. nitrogen-fixation in northern european boreal forests has been estimated at only 0.5 kg n ha(- ...	2002	12410308
the uv-b stimulon of the terrestrial cyanobacterium nostoc commune comprises early shock proteins and late acclimation proteins.	the uv-b and desiccation-tolerant terrestrial cyanobacterium nostoc commune was grown under defined uv irradiation. proteome changes were monitored in the membrane and the cytosolic and the extracellular fractions. tools were developed to separate stress-triggered from growth stage-dependent changes. uv-b changed the relative cellular concentration of 493 out of 1,350 protein spots at least by a factor of three, rendering the uv-b stimulon of n. commune the most complex one described so far. it ...	2002	12410839
cellular differentiation in the cyanobacterium nostoc punctiforme.	nostoc punctiforme is a phenotypically complex, filamentous, nitrogen-fixing cyanobacterium, whose vegetative cells can mature in four developmental directions. the particular developmental direction is determined by environmental signals. the vegetative cell cycle is maintained when nutrients are sufficient. limitation for combined nitrogen induces the terminal differentiation of heterocysts, cells specialized for nitrogen fixation in an oxic environment. a number of unique regulatory events an ...	2002	12420158
isolation of the gene for the b12-dependent ribonucleotide reductase from anabaena sp. strain pcc 7120 and expression in escherichia coli.	the gene for ribonucleotide reductase from anabaena sp. strain pcc 7120 was identified and expressed in escherichia coli. this gene codes for a 1,172-amino-acid protein that contains a 407-amino-acid intein. the intein splices itself from the protein when it is expressed in e. coli, yielding an active ribonucleotide reductase of 765 residues. the mature enzyme was purified to homogeneity from e. coli extracts. anabaena ribonucleotide reductase is a monomer with a molecular weight of approximatel ...	2002	12426342
[use of cyanobacteria for indication of toxic action of stachybotrys toxins].	screening of cyanobacteria cultures for their sensitivity to the action of complex preparations of toxins from 18 strains of stachybotrys chartarum has been carried out with the purpose to search for new test-organisms to create a reliable system of biotesting of stachibotryotoxines. in contrast to other cultures of unicell (anacystis nidulans) and filamentous (anabaena sp., anabaena variabilis, nostoc linckia, plectonema boryanum) cyanobacteria used in the experiment, only one culture of unicel ...	2002	12436869
solution nmr structure and backbone dynamics of the psae subunit of photosystem i from synechocystis sp. pcc 6803.	psae is a small peripheral subunit of photosystem i (psi) that is very accessible to the surrounding medium. it plays an essential role in optimizing the interactions with the soluble electron acceptors of psi, ferredoxin and flavodoxin. the solution structure of psae from the cyanobacterium synechocystis sp. pcc 6803 has been investigated by nmr with a special emphasis on its protein dynamic properties. psae is characterized by a well-defined central core that consists of a five-stranded beta-s ...	2002	12437347
[formation of giant and ultramicroscopic forms of nostoc muscorum calu 304 during cocultivation with rauwolfia tissues].	the study of heteromorphic nostoc muscorum calu 304 cells, whose formation was induced by 6- to 7-week cocultivation with the rauwolfia callus tissues under unfavorable conditions, revealed the occurrence of giant cell forms (gcfs) with a volume which was 35-210 times greater than that of standard cyanobacterial cells. some gcfs had an impaired structure of the murein layer of the cell wall, which resulted in the degree of impairment of the cell wall ranging from the mere loss of its rigidity to ...	2002	12449632
molecular characteristics of glna linked mutations in the nitrogen-fixing cyanobacterium nostoc muscorum.	the glutamine synthetase (gs)-impaired mutants of nostoc muscorum, isolated as ethylenediamine (eda) resistant phenotype, were characterized for glna linked processes to investigate the molecular mechanism of gs impairment. the gs enzyme was purified to homogeneity from the wild and mutant strains of n. muscorum employing ion-exchange followed by affinity chromatography. the final yield and specific activity of the enzyme were low in the mutant strains as compared to the wild type. the molecular ...	2002	11815852
immobilization results in sustained calcium transport in nostoc calcicola bréb.	the uptake pattern of ca2+ by the cyanobacterium nostoc calcicola bréb in its freely suspended and immobilized form is comprised of two distinct phages; (a) rapid uptake for 1st 10 min followed by (b) slower transport at least up to 60 min. entrapment of cyanobacterial cells in polyvinyl foam always maintained a higher ca2+ profile over freely suspended cells. also, the intracellular ca2+ concentration was three times more in the former under similar experimental conditions. whereas, illuminatio ...	2002	11821924
mycobacterium smegmatis and tuberculosis.		2002	11827806
classification of the caspase-hemoglobinase fold: detection of new families and implications for the origin of the eukaryotic separins.	a comprehensive sequence and structural comparative analysis of the caspase-hemoglobinase protein fold resulted in the delineation of the minimal structural core of the protease domain and the identification of numerous, previously undetected members, including a new protease family typified by the hetf protein from the cyanobacterium nostoc. the first bacterial homologs of legumains and hemoglobinases were also identified. most proteins containing this fold are known or predicted to be active p ...	2002	11835511
long-term microclimatic stress causes rapid adaptive radiation of kaiabc clock gene family in a cyanobacterium, nostoc linckia, from "evolution canyons" i and ii, israel.	cyanobacteria are the only prokaryotes known thus far possessing regulation of physiological functions with approximate daily periodicity, or circadian rhythms, that are controlled by a cluster of three genes, kaia, kaib, and kaic. here we demonstrate considerably higher genetic polymorphism and extremely rapid evolution of the kaiabc gene family in a filamentous cyanobacterium, nostoc linckia, permanently exposed to the acute natural environmental stress in the two microsite evolutionary models ...	2002	11842226
the cryptophycins: their synthesis and anticancer activity.	the cryptophycins are a unique family of 16-membered macrolide antimitotic agents isolated from the cyanobacteria nostoc sp. their molecular target is tubulin protein wherein they are the most potent known stabilizers of microtubule dynamics and depolymerize microtubules at higher concentrations. they also deactivate the bcl2 protein and produce apoptotic response much more quickly and at considerably lower concentrations than clinically utilized compounds. the presence of several amide and este ...	2002	11857635
recovery of photosynthetic systems during rewetting is quite rapid in a terrestrial cyanobacterium, nostoc commune.	recovery processes of photosynthetic systems during rewetting were studied in detail in a terrestrial, highly drought-tolerant cyanobacterium, nostoc commune. with absorption of water, the weight of n. commune colony increased in three phases with half-increase times of about 1 min, 2 h and 9 h. fluorescence intensities of phycobiliproteins and photosystem (ps) i complexes were recovered almost completely within 1 min, suggesting that their functional forms were restored very quickly. energy tra ...	2002	11867696
the devt protein stimulates synthesis of frua, a signal transduction protein required for fruiting body morphogenesis in myxococcus xanthus.	fruiting body formation in myxococcus xanthus involves three morphologic stages---rippling, aggregation, and sporulation---all of which are induced by the cell surface-associated c-signal. we analyzed the function of the devt protein, a novel component in the c-signal response pathway. a mutant carrying an in-frame deletion in the devt gene displays delayed aggregation and a cell autonomous sporulation defect, whereas it remains rippling proficient. to further define the function of devt, the me ...	2002	11872704
hydrogenases and hydrogen metabolism of cyanobacteria.	cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupsl) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxfuyh) which has the capacity to both take up and produce hydrogen. this review summarizes our knowledge about cyanobacterial hydrogenases ...	2002	11875125
genetic tools for cyanobacteria.	cyanobacteria are oxygenic photosynthetic bacteria that have been used increasingly to study diverse biological processes, including photosynthesis and its regulation; cell differentiation and n2 fixation; metabolism of nitrogen, carbon, and hydrogen; resistance to environmental stresses; and molecular evolution. many vectors and other genetic tools have been developed for unicellular and filamentous strains of cyanobacteria. transformation, electroporation, and conjugation are used for gene tra ...	2002	11876404
crystal structure of the opca integral membrane adhesin from neisseria meningitidis.	opca is an integral outer membrane protein from neisseria meningitidis, the causative agent of meningococcal meningitis and septicemia. it mediates the adhesion of n. meningitidis to epithelial and endothelial cells by binding to vitronectin and proteoglycan cell-surface receptors. here, we report the determination of the crystal structure of opca to 2.0 a resolution. opca adopts a 10-stranded beta-barrel structure with extensive loop regions that protrude above the predicted surface of the memb ...	2002	11891340
fasciclin domain proteins are present in nostoc symbionts of lichens.	differences in the soluble protein fraction between the freshly isolated cyanobiont of lichen peltigera membranacea, the corresponding free-living strain, and nostoc punctiforme were analyzed. one protein, which was among the most prominent proteins of the freshly isolated cyanobiont, was expressed at a lower level in the corresponding free-living strain and was not detected at all on the two-dimensional gels of n. punctiforme. this protein was partially sequenced, and the corresponding open rea ...	2002	11916728
transcriptional regulation of nostoc hydrogenases: effects of oxygen, hydrogen, and nickel.	the transcription of structural genes encoding two hydrogenases in n(2)-fixing cultures of the cyanobacteria nostoc muscorum and nostoc sp. strain pcc 73102 were examined by reverse transcription-pcr. a low level of oxygen and addition of nickel induce higher transcript levels of both hydrogenases, whereas molecular hydrogen has a positive effect on the transcription of the genes encoding only the uptake hydrogenase.	2002	11772661
establishment of a functional symbiosis between the cyanobacterium nostoc punctiforme and the bryophyte anthoceros punctatus requires genes involved in nitrogen control and initiation of heterocyst differentiation.	three mutant strains (ntca, hetr, hetf) of the cyanobacterium nostoc punctiforme unable to differentiate heterocysts were characterized and examined for their ability to form a symbiotic association with the bryophyte anthoceros punctatus. previously unknown characteristics of the n. punctiforme hetr mutant include differentiation of chilling-resistant akinetes, while vegetative cells of the ntca mutant randomly lysed, yielding short filaments, following ammonium deprivation. strains with mutati ...	2002	11782524
nested evolution of a trna(leu)(uaa) group i intron by both horizontal intron transfer and recombination of the entire trna locus.	the origin and evolution of bacterial introns are still controversial issues. here we present data on the distribution and evolution of a recently discovered divergent trna(leu)(uaa) intron. the intron shows a higher sequence affiliation with introns in trna(ile)(cau) and trna(arg)(ccu) genes in alpha- and beta-proteobacteria, respectively, than with other cyanobacterial trna(leu)(uaa) group i introns. the divergent trna(leu)(uaa) intron is sporadically distributed both within the nostoc and the ...	2002	11790735
evolution of sucrose synthesis.	cyanobacteria and proteobacteria (purple bacteria) are the only prokaryotes known to synthesize sucrose (suc). suc-p synthase, suc-phosphatase (spp), and suc synthase activities have previously been detected in several cyanobacteria, and genes coding for suc-p synthase (sps) and suc synthase (sus) have been cloned from synechocystis sp. pcc 6803 and anabaena (nostoc) spp., respectively. an open reading frame in the synechocystis genome encodes a predicted 27-kd polypeptide that shows homology to ...	2002	11950997
viability of dried filaments, survivability and reproduction under water stress, and survivability following heat and uv exposure in lyngbya martensiana, oscillatoria agardhii, nostoc calcicola, hormidium fluitans, spirogyra sp. and vaucheria geminata.	dried vegetative filaments of spirogyra sp., vaucheria geminata and nostoc calcicola died within 1/2, 1 and 4 h, respectively; those of hormidium fluitans, oscillatoria agardhii and lyngbya martensiana retained under similar storage conditions viability for 3, 5 and 10 d, respectively. the viability of dried vegetative filaments of l. martensiana, o. agardhii and h. fluitans decreased on storage at 20 degrees c in the dark. l. martensiana and o. agardhii tolerated 0.8 mol/l nacl. the resistance ...	2002	11980272
temporal variation in community composition, pigmentation, and f(v)/f(m) of desert cyanobacterial soil crusts.	summers on the colorado plateau (usa) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high uv and visible radiation. we investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. representative surface cores were sampled at the ene, wsw, and top microaspects of 20 individual soil crust pedicels at a single site in canyonlands national park, utah, in spring an ...	2002	11984625
isolation and characterization of mutants of two diazotrophic cyanobacteria tolerant to high concentrations of inorganic carbon.	diazotrophic heterocystous cyanobacteria nostoc calcicola and anabaena sp. arm 629 were investigated for their ability to grow in presence of sodium bicarbonate (nahco3) or carbon dioxide (co2) under cultural conditions. maximum growth was observed in 75 mm nahco3 and 5% co2 in n. calcicola and anabaena arm 629, respectively. although their growth rate declined, n. calcicola and anabaena sp. could tolerate upto 250 mm nahco3 and 20% co2, respectively. n-methyl-n'-nitro n nitrosoguanidine induced ...	2002	12002405
purification and properties of an enzyme capable of degrading the polysaccharide of the cyanobacterium, nostoc commune.	a novel nostoc commune-polysaccharide (nps)-degrading enzyme with a molecular mass of 128.5 kda was purified from paenibacillus glycanilyticus ds-1. the optimum ph and temperature of the enzyme activity were 5.5 and 35 degrees c, respectively. the enzyme completely degraded nps to oligosaccharides, ranging from tetra to hexasaccharides and could degrade the xylan weakly whereas xanthan, gellan, cellulose, curdlan and p-nitrophenyl-beta-d-xylopyranoside were not degraded. homology analysis of the ...	2002	12562091
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
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
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
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
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
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
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
relation between domain evolution, specificity, and taxonomy of the alpha-amylase family members containing a c-terminal starch-binding domain.	the alpha-amylase family (glycoside hydrolase family 13; gh 13) contains enzymes with approximately 30 specificities. six types of enzyme from the family can possess a c-terminal starch-binding domain (sbd): alpha-amylase, maltotetraohydrolase, maltopentaohydrolase, maltogenic alpha-amylase, acarviose transferase, and cyclodextrin glucanotransferase (cgtase). such enzymes are multidomain proteins and those that contain an sbd consist of four or five domains, the former enzymes being mainly hydro ...	2003	12581203
a two-component regulator of universal stress protein expression and adaptation to oxygen starvation in mycobacterium smegmatis.	we identified a response regulator in mycobacterium smegmatis which plays an important role in adaptation to oxygen-starved stationary phase. the regulator exhibits strong sequence similarity to devr/rv3133c of m. tuberculosis. the structural gene is present on a multigene locus, which also encodes a sensor kinase. a devr mutant of m. smegmatis was adept at surviving growth arrest initiated by either carbon or nitrogen starvation. however, its culturability decreased several orders of magnitude ...	2003	12591871
biosynthesis of 4-methylproline in cyanobacteria: cloning of nose and nosf genes and biochemical characterization of the encoded dehydrogenase and reductase activities.	the biosynthesis of the unusual amino acid 4-methylproline in the nostoc genus of cyanobacteria was investigated on the genetic and enzymatic level. two genes involved in the biosynthesis were cloned and the corresponding enzymes, a zinc-dependent long-chain dehydrogenase and a delta(1)-pyrroline-5-carboxylic acid (p5c) reductase homologue, were overexpressed in escherichia coli and biochemically characterized. putative substrates were synthesized to test enzyme substrate specificities, and deut ...	2003	12515465
dna binding properties of the hrmr protein of nostoc punctiforme responsible for transcriptional regulation of genes involved in the differentiation of hormogonia.	nostoc punctiforme is an example of a filamentous cyanobacterium that is capable of differentiating non-growing cells that constitute gliding filaments termed hormogonia. these gliding filaments serve in short distance dispersal and as infective units in establishing a symbiosis with plants, such as the bryophyte anthoceros punctatus. mutants of n. punctiforme exist which show elevated levels of initial infection of a. punctatus as a consequence of repeated cycles of hormogonium differentiation. ...	2003	12519206
bioactivities of nostocine a produced by a freshwater cyanobacterium nostoc spongiaeforme tistr 8169.	a freshwater cyanobacterium, nostoc spongiaeforme tistr 8169, synthesizes and releases a violet pigment, nostocine a, into medium. we examined the bioactivity of nostocine a to several model organisms breeding with n. spongiaeforme in the natural environment. to microalgae, nostocine a exhibited growth inhibitory activity comparable to paraquat, and the activity tended to be stronger to green algae than to cyanobacteria. nostocine a also exhibited strong inhibitory activity to the root elongatio ...	2003	16233448
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
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