Publications

evidence for the involvement of a common genetic determinant in the control of thallium-resistant (tl1-r) phenotype and salinity-tolerant phenotype in the cyanobacterium nostoc muscorum.		2000	12483581
a novel extracellular diterpenoid with antibacterial activity from the cyanobacterium nostoc commune.	a novel extracellular metabolite with an unprecedented diterpenoid skeleton, 8-[(5-carboxy-2-hydroxy)benzyl]-2-hydroxy-1,1,4a,7, 8-pentamethyl-1,2,3,4,4a,6,7,8,8a,9,10,10a-dodecahydrophenanthrene , has been isolated from the culture medium of the terrestrial cyanobacterium nostoc commune vaucher (eawag 122b) by means of bioguided isolation. the molecule was designated as noscomin. the structure was determined by spectroscopic methods, mainly nmr and mass spectrometry. noscomin exhibited antibact ...	1999	10096870
cyanovirin-n binds to gp120 to interfere with cd4-dependent human immunodeficiency virus type 1 virion binding, fusion, and infectivity but does not affect the cd4 binding site on gp120 or soluble cd4-induced conformational changes in gp120.	cyanovirin-n (cv-n), an 11-kda protein isolated from the cyanobacterium nostoc ellipsosporum, potently inactivates diverse strains of human immunodeficiency virus type 1 (hiv-1), hiv-2, and simian immunodeficiency virus. while it has been well established that the viral surface envelope glycoprotein gp120 is a molecular target of cv-n, the detailed mechanism of action is of further interest. we compared matched native and cv-n-treated virus preparations in a panel of assays that measure viral re ...	1999	10196334
extended heme promiscuity in the cyanobacterial cytochrome c oxidase: characterization of native complexes containing hemes a, o, and d, respectively.	the cyanobacteria anacystis nidulans (synechococcus sp. pcc6301), synechocystis sp. pcc6803, anabaena sp. pcc 7120, and nostoc sp. pcc8009 were grown photoautotrophically under reduced oxygen tension in a medium with sulfate replaced by thiosulfate and nitrate replaced by ammonium as the s- and n-sources, respectively. in addition, anabaena and nostoc were grown under dinitrogen-fixing conditions in a medium free of combined nitrogen. membranes were isolated from late-logarithmic cells (culture ...	1999	10375407
biochemical and genetic evidence for participation of devr in a phosphorelay signal transduction pathway essential for heterocyst maturation in nostoc punctiforme atcc 29133.	in a test of the hypothesis that devr is a response regulator protein that functions in a phosphorelay signal transduction system involved in heterocyst development in nostoc punctiforme atcc 29133, purified affinity-tagged devr was shown to be phosphorylated in vitro by the noncognate sensor kinase envz. site-directed mutagenesis was used to generate n. punctiforme mutants with single amino acid substitutions at the putative phosphorylation site of devr. these mutants exhibited a fox- phenotype ...	1999	10400605
energy-dependent ca(2+) efflux from the cells of nostoc calcicola breb: role of modifying factors	energy-dependent ca(2+) efflux and its regulation from the diazotrophic cyanobacterium nostoc calcicola breb has been investigated. like ca(2+) uptake, ca(2+) efflux pattern also reflected a rapid phase for the first 10 min followed by a slower one lasting up to 1 h with a total of 80 nmol ca(2+) mg(-1) protein (31% of the ca(2+) concentration taken in by such cells at 1 h). ca(2+) efflux kinetics remained hyperbolic with a k(m) of 1.9 mm and v(max) 5.5 nmol mg(-1) protein min(-1). ca(2+) efflux ...	1999	10489433
the solution structure of photosystem i accessory protein e from the cyanobacterium nostoc sp. strain pcc 8009.	psae is a small basic subunit located on the stromal (cytoplasmic) side of photosystem i. in cyanobacteria, this subunit participates in cyclic electron transport and modulates the interactions of the complex with soluble ferredoxin. the psae protein isolated from the cyanobacterium synechococcus sp. strain pcc 7002 adopts the beta topology of an sh3 domain, with five beta strands (betaa through betae) and a turn of 3(10) helix between strands betad and betae [falzone, c. j., kao, y.-h., zhao, j ...	1999	10521281
separation and identification of hydrocarbons and other volatile compounds from cultured blue-green alga nostoc sp. by gas chromatography-mass spectrometry using serially coupled capillary columns with consecutive nonpolar and semipolar stationary phases.	the complex hydrocarbons and volatile compounds produced by cultured blue-green alga nostoc sp. were separated by serially coupled capillary columns with consecutive nonpolar and semipolar stationary phases. more than 130 metabolites including, cyclohexane, cyclopentane, normal saturated hydrocarbons (c7-c30), fatty acids and benzene derivatives were identified by gc-ms. the most abundant family of hydrocarbons identified were derivatives of cyclohexane (41) and cyclopentane (11). most of these ...	1999	10596980
host specificity in the richelia-diatom symbiosis revealed by hetr gene sequence analysis.	the filamentous heterocyst-forming cyanobacterium richelia intracellularis forms associations with diatoms and is very abundant in tropical and subtropical seas. the genus richelia contains only one species, r. intracellularis schmidt, although it forms associations with several diatom genera and has considerable variation in size and morphology. the genetic diversity, and possible host specificity, within the genus richelia is unknown. using primers against hetr, a gene unique for filamentous c ...	1999	11207763
transcriptional regulation of nostoc uptake hydrogenase.	filamentous, heterocystous cyanobacteria may contain both an uptake hydrogenase (encoded by hupsl) and a bidirectional enzyme (encoded by hoxfuyh). the present study identifies three strains (anabaena variabilis, nostoc muscorum and nostoc sp. strain pcc 73102) with a contiguous hupl in both vegetative cells and heterocysts. the two nostoc strains differ in either containing a bidirectional enzyme (n. muscorum) or lacking this enzyme (n. pcc 73102). transcriptional studies, using reverse transcr ...	1999	9919654
a cyanobacterial hemoglobin with unusual ligand binding kinetics and stability properties.	the glbn gene of the cyanobacterium nostoc commune utex 584 encodes a hemoprotein, named cyanoglobin, that has high oxygen affinity. the basis for the high oxygen affinity of cyanoglobin was investigated through kinetic studies that utilized stopped-flow spectrophotometry and flash photolysis. association and dissociation rate constants were measured at 20 degrees c for oxygen, carbon monoxide, nitric oxide, and methyl and ethyl isocyanides. the association rate constants for the binding of thes ...	1999	10026295
the frua signal transduction protein provides a checkpoint for the temporal co-ordination of intercellular signals in myxococcus xanthus development.	during fruiting body morphogenesis in myxococcus xanthus, the intercellular c-signal induces aggregation, sporulation and developmental gene expression. to understand how a single signal system may induce temporally separated processes, we have focused on the class ii gene, which codes for an essential component in the c-signal transduction pathway. we report that class ii is identical to frua and codes for a dna binding response regulator. transcription of frua is developmentally regulated and ...	1998	10094629
hydrogen uptake in nostoc sp. strain pcc 73102. cloning and characterization of a hupsl homologue.	structural genes encoding an uptake hydrogenase of nostoc sp. strain pcc 73102 were isolated. from partial libraries of genomic dna, two clones (pnfo01 and pnfo02) were selected and sequenced, revealing the complete sequence of both a hups (960 bases) and a hupl (1,593 bases) homologue in nostoc sp. strain pcc 73102. a comparison between the deduced amino acid sequences of hups and hupl of nostoc sp. strain pcc 73102 and anabaena sp. strain pcc 7120 showed that the hups proteins are 89% identica ...	1998	9531626
electrophoretic applications of phycobiliproteins.	phycobiliproteins are homologous chromoproteins which constitute the phycobilisomes, the light harvesting complexes of the photosynthetic apparatus in cyanobacteria, rhodophyta and cryptophyta. in the present work, phycocyanin (pc) and phycoerythrin (pe) from a nostoc species are proposed as protein markers for electrophoretic techniques. phycocyanin is a blue-colored phycobiliprotein; it carries phycocyanobilin as chromophoric group and is composed of two subunits, alpha and beta, with mr of 14 ...	1998	9548282
sequence variation of the trna(leu) intron as a marker for genetic diversity and specificity of symbiotic cyanobacteria in some lichens.	we examined the genetic diversity of nostoc symbionts in some lichens by using the trna(leu) (uaa) intron as a genetic marker. the nucleotide sequence was analyzed in the context of the secondary structure of the transcribed intron. cyanobacterial trna(leu) (uaa) introns were specifically amplified from freshly collected lichen samples without previous dna extraction. the lichen species used in the present study were nephroma arcticum, peltigera aphthosa, p. membranacea, and p. canina. introns w ...	1998	9435083
uvb-induced reduction in biomass and overall productivity of cyanobacteria.	effect of middle wave ultraviolet radiation (uvb) was studied in three different species of cyanobacteria (nostoc, anabaena and scytonema) by estimating their growth pattern, biomass yield, chlorophyll content, total starch and protein content. the results show that exposure of the cyanobacteria with uvb dose corresponding to an increase or decrease of 20% in its environmental flux will have drastic effects on biomass production, photosynthetic rate and nitrogen fixation. cyanobacteria are prima ...	1998	9514891
cloning and characterisation of the pknd gene encoding an eukaryotic-type protein kinase in the cyanobacterium anabaena sp. pcc7120.	protein phosphorylation catalysed by protein kinases is an important mechanism for signal transduction in both prokaryotes and eukaryotes. a novel gene, pknd, encoding a protein similar to eukaryotic-type protein kinases, was cloned from anabaena sp. pcc7120. the n-terminal region of pknd is 60% identical to that of pkna, another putative ser/thr kinase from the same strain. both pkna and pknd have c-terminal regions that are rich in pro and thr residues. expression of pknd was undetectable by r ...	1998	9613569
characterization of the glnb gene product of nostoc punctiforme strain atcc 29133: glnb or the pii protein may be essential.	bacterial pii proteins, encoded by glnb genes, are central signalling molecules in nitrogen regulatory pathways and are modulated by post-translational modification in response to the cellular nitrogen status. the glnb gene was cloned from the filamentous heterocyst-forming cyanobacterium nostoc punctiforme strain atcc 29133 (pcc 73102) by heterologous hybridization to a synechococcus sp. strain pcc 7942 gene fragment. expression of the cloned gene was verified by hybridization to n. punctiforme ...	1998	9639924
multiple oligomeric forms of glucose-6-phosphate dehydrogenase in cyanobacteria and the role of opca in the assembly process.	multiple molecular forms of glucose-6-phosphate dehydrogenase (g6pdh) were detected by activity staining in non-denaturing polyacrylamide gels of cell-free extracts from a range of cyanobacteria including anabaena sp. pcc 7120, synechococcus sp. pcc 7942, plectonema boryanum pcc 73110, synechocystis sp. pcc 6803, nostoc sp. mac pcc 8009 and the marine strain synechococcus sp. wh7803. in most of the species tested, the profile of g6pdh activities was modulated by the growth of the cells in the pr ...	1998	9639925
evolution of cyanobacteria by exchange of genetic material among phyletically related strains.	the cyanobacterial radiation consists of several lineages of phyletically (morphologically and genetically) related organisms. several of these organisms show a striking resemblance to fossil counterparts. to investigate the molecular mechanisms responsible for stabilizing or homogenizing cyanobacterial characters, we compared the evolutionary rates and phylogenetic origins of the small-subunit rrna-encoding dna (16s rdna), the conserved gene rbcl (encoding d-ribulose 1,5-bisphosphate carboxylas ...	1998	9642201
binding of the epoxide cryptophycin analog, ly355703 to albumin and its effect on in vitro antiproliferative activity.	cryptophycin, isolated from the cyanobacterium nostoc, is a cytotoxic dioxadiazacyclohexadecenetetrone which causes rapid depletion of microtubules in intact cells. in the present report, the effect of protein binding of a new synthetic cryptophycin analog, ly355703 (cryptophycin 52), is discussed. in handling the compound, it was found to bind extensively to surfaces, and a high degree of plasma protein binding was also observed (about 99% in human plasma). similarly, while ly355703 displays po ...	1998	9683814
structure and properties in solution of psad, an extrinsic polypeptide of photosystem i.	psad is a small, extrinsic polypeptide located on the stromal side (cytoplasmic side in cyanobacteria) of the photosystem i reaction centre complex. the gene from the cyanobacterium nostoc sp. pcc 8009 was expressed in escherichia coli and the structure of the recovered protein in solution investigated. size-exclusion chromatography, dynamic light scattering and measurement of 15n transverse relaxation times showed that the protein is a stable dimer in solution, whereas in the reaction centre co ...	1998	9692933
a transposition-induced mutant of nostoc ellipsosporum implicates an arginine-biosynthetic gene in the formation of cyanophycin granules and of functional heterocysts and akinetes.	in strain ne1 of tn5-1058-mutagenized nostoc ellipsosporum, the transposon was found within a gene whose translation product is similar in amino acid sequence to the arginine-biosynthetic protein n-acetylglutamate semialdehyde dehydrogenase encoded by argc of bacillus subtilis. the argc reported from anabaena sp. strain pcc 7120 hybridized to a sequence different from the one interrupted by the transposon in ne1. the newly identified gene from n. ellipsosporum was denoted argl. the argl mutation ...	1998	9695912
cellular uptake of a novel cytotoxic agent, cryptophycin-52, by human thp-1 leukemia cells and h-125 lung tumor cells.	cryptophycin (cp) is a newly developed anticancer agent isolated from the terrestrial cyanobacteria of the genus nostoc. cp is a mitotic inhibitor, causing cells to accumulate in mitosis with the disappearance of intracellular microtubules. in this report, we studied the interaction and uptake of a new synthetic cp analog, cp-52, with 2 human tumor cell lines, thp-1 and h-125. in vitro colony-forming assay showed that cp-52 has antiproliferative activity against thp-1 and h-125 cell lines with i ...	1998	9714056
partial purification and characterization of ornithine carbamoyl transferase (oct) from the cyanobacterium nostoc sp. strain pcc 73102	ornithine carbamoyl transferase (oct) catalyzes the formation of citrulline and orthophosphate from ornithine and carbamoyl phosphate. we have partially purified oct from the filamentous cyanobacterium nostoc sp. strain pcc 73102, using ammonium sulfate precipitation (35-55%), a gel-filtration column (sephacryl s-200), followed by an affinity column (sepharose-6b-palo). the partially purified oct was analyzed on native-page and shown to be an active enzyme with an estimated molecular weight of a ...	1998	9732532
mutation of an alternative sigma factor in the cyanobacterium nostoc punctiforme results in increased infection of its symbiotic plant partner, anthoceros punctatus.	an alternative group 2 sigma factor was identified in the nitrogen-fixing, symbiotically competent cyanobacterium nostoc punctiforme and designated sigh. transcription of sigh was specifically induced within 1.5 h following exposure of n. punctiforme to its symbiotic plant partner, anthoceros punctatus. a mutation in sigh resulted in a sixfold-higher initial infection of a. punctatus tissue without a parallel increase in nitrogen-fixing activity.	1998	9733698
a simple procedure for purifying the major chloroplast fructose-1,6-bisphosphatase from spinach (spinacia oleracea) and characterization of its stimulation by sub-femtomolar mercuric ions.	a rapid procedure for the purification of the redox-regulated chloroplast fructose-1,6-bisphosphatase [ec 3.1.3.11] from spinach leaf extract to homogeneity is described. no thiol-reducing agents were present during the purification and the enzyme is > 99% in the oxidized form. a rapid procedure to reduce and activate the fru-1,6-p2ase by dithiothreitol in the absence of thioredoxin is described. reduction activates the enzyme up to several hundred-fold when assayed at ph 8.0 with 2 mm mg2+. the ...	1998	9735161
tenuecyclamides a-d, cyclic hexapeptides from the cyanobacterium nostoc spongiaeforme var. tenue.	four modified cyclic hexapeptides, tenuecyclamides a-d (1-4), were isolated along with the known antibiotic, borophycin (5), from the methanol extract of nostoc spongiaeforme var. tenue (tau strain il-184-6). the planar structure of tenuecyclamides a-d (1-4) was determined by homonuclear and inverse-heteronuclear 2d-nmr techniques as well as by high-resolution mass spectrometry measurements. the absolute configuration of the asymmetric centers was studied by marfey's method for hplc. the stereoc ...	1998	9784161
differential behaviour of two cyanobacterium species to uv radiation. artificial uv radiation induces phycoerythrin synthesis.	altitude is an important factor contributing to the local uv-b climate. in the european alps solar uv-b increases approximately 21% 1000 m-1. a nostoc muscorum (utex 389) originating from scotland and a nostoc sp. isolated from a highland lake (yanaqocha) located 3980 m above sea level (cusco, perú) have been used in a study where the tolerance to uv radiation (uvr) stress of both species was determined. following irradiation doses of 15 kj uv (uv-a plus uv-b, equivalent to approximately 6 h exp ...	1998	9800379
a pcr technique based on the hip1 interspersed repetitive sequence distinguishes cyanobacterial species and strains.	the use of primers based on the hip1 sequence as a typing technique for cyanobacteria has been investigated. the discovery of short repetitive sequence structures in bacterial dna during the last decade has led to the development of pcr-based methods for typing, i.e., distinguishing and identifying, bacterial species and strains. an octameric palindromic sequence known as hip1 has been shown to be present in the chromosomal dna of many species of cyanobacteria as a highly repetitious intersperse ...	1998	9802020
safety evaluation of nostoc flagelliforme (nostocales, cyanophyceae) as a potential food.	the safety of the alga genus nostoc flagelliforme born. etflah. as a human food source was evaluated in an oral acute toxicity study and in a 28-day oral subacute toxicity study using rats. in the acute toxicity study, the dried powder of n. flagelliforme was orally administered to male and female rats at a dose of 1250 mg/kg and 2500 mg/kg. neither mortality nor changes in general condition were observed in either the study groups or the control group over a 14-day observation period. in the su ...	1998	9862649
fingerprinting of cyanobacteria based on pcr with primers derived from short and long tandemly repeated repetitive sequences.	the presence of repeated dna (short tandemly repeated repetitive [strr] and long tandemly repeated repetitive [ltrr]) sequences in the genome of cyanobacteria was used to generate a fingerprint method for symbiotic and free-living isolates. primers corresponding to the strr and ltrr sequences were used in the pcr, resulting in a method which generate specific fingerprints for individual isolates. the method was useful both with purified dna and with intact cyanobacterial filaments or cells as te ...	1998	16349487
freshwater cyanobacterium microcystis aeruginosa (utex 2385) induced dna damage in vivo and in vitro.	microcystins are a family of potent hepatotoxins and liver tumor promoters produced by several genera of cyanobacteria including microcystis, nodularia, anabena, nostoc, etc. they are chemically very stable and represent a public health threat when they occur in water used for human consumption. we investigated the dna damage effects of m. aeruginosa utex 2385 in mouse liver in vivo and also in mammalian cells in vitro. the dna damage effect is compared with purified toxin microcystin-lr (mclr) ...	1998	21781844
cyanobacteria as agents for the control of pollution by pesticides and chlorinated organic compounds.	cyanobacteria are phototrophic aquatic micro-organisms that are found in a variety of environments, including polluted ones. fifteen strains of cyanobacteria that belong to three taxonomic groups are able to degrade lindane (λ-hexachlorocyclohexane, a recalcitrant pesticide). the initial degradation pathway has been studied in two filamentous nitrogen-fixing strains of anabaena sp. pcc 7120 and nostoc ellipsosporum. these cyanobacteria dechlorinated loindane first to pentachlorocyclohexene and t ...	1998	21182708
hydrogenases in nostoc sp. strain pcc 73102, a strain lacking a bidirectional enzyme.	the present study was carried out in order to examine and characterize the bidirectional hydrogenase in the cyanobacterium nostoc sp. strain pcc 73102. southern hybridizations with the probes av1 and av3 (hoxy and hoxh, bidirectional hydrogenase small and large subunits, respectively) revealed the occurrence of corresponding sequences in anabaena variabilis (control), anabaena sp. strain pcc 7120, and nostoc muscorum but not in nostoc sp. strain pcc 73102. as a control, hybridizations with the p ...	1997	16535596
phenotypic and genotypic comparison of symbiotic and free-living cyanobacteria from a single field site.	pcr amplification techniques were used to compare cyanobacterial symbionts from a cyanobacterium-bryophyte symbiosis and free-living cyanobacteria from the same field site. thirty-one symbiotic cyanobacteria were isolated from the hornwort phaeoceros sp. at several closely spaced locations, and 40 free-living cyanobacteria were isolated from the immediate vicinity of the same plants. one of the symbiotic isolates was a species of calothrix, a genus not previously known to form bryophyte symbiose ...	1997	16535734
[the destruction of microscopic organisms by their irradiation with a special form of uhf electromagnetic signals].	electromagnetic signals of special form produced by an ultra-high frequency generator were used to destroy various microorganisms: baker's yeast; blue-green alga nostoc muscorum; mold fungus; and two flagellates, plant flagellate euglena gracilis and an animal flagellate parasitizing on humans. the control samples before irradiation and experimental samples damaged and destroyed by irradiation were examined on a microscope with a computer system of image analysis. the results are presented as co ...	1997	9518060
glutamine synthetase from n2-fixing cyanobacterium nostoc muscorum--purification, biochemical and immunological characteristics.	a modified procedure for purification of glutamine synthetase [l-glutamate: ammonia ligase (adp-forming)] from n2-fixing cyanobacterium n. muscorum, to homogeneity is described using deae-sephadex and blue-sepharose affinity chromatography. specific activities of the purified enzyme in biosynthetic and transferase assays were 8.5 and 28 mumole product formed min-1 mg-1 protein. apparent molecular mass of native gs enzyme was about 610 kda as estimated by gel filtration. on sds-page the enzyme pr ...	1997	9475046
a comparison of physical properties, oxalate-oxalic acid soluble substances, protein content, and in vitro protein digestibility of the blue-green alga nostoc commune vauch. from the philippines and japan.	the physical properties, amount of oxalate-oxalic acid soluble substances (ooss), protein and in vitro protein digestibility of nostoc commune from the philippines and japan were determined. the samples were the spherical type from the philippines (ps), the dry field discoid type from the philippines (pd), and the dry field discoid type from japan (jd). the discoid types, pd and jd, regardless of origin showed higher settling volume in water (sv) and bulk density than ps. the ooss values obtaine ...	1997	9477423
characterization of host-range mutants of cyanophage n-1.	fifteen host-range (h) mutants of cyanophage n-1 were characterized with reference to their efficiency of plating, time of appearance, morphology and size of plaques on nostoc muscorum and its three phage-resistant (nm 1/n-1, nm 2/n-1 and nm 8/n-1) mutants. while phage n-1 did not adsorb to the three phage-resistant mutants, the h mutants differed one from the other in having lower or higher adsorption rate constants on n. muscorum or the phage-resistant mutants. the inability of majority of h m ...	1997	9607077
amino acid transport in taxonomically diverse cyanobacteria and identification of two genes encoding elements of a neutral amino acid permease putatively involved in recapture of leaked hydrophobic amino acids.	the activities of uptake of thirteen 14c-labeled amino acids were determined in nine cyanobacteria, including the unicellular strains synechococcus sp. strain pcc 7942 and synechocystis sp. strain pcc 6803; the filamentous strain pseudanabaena sp. strain pcc 6903, and the filamentous, heterocyst-forming strains anabaena sp. strains pcc 7120 and pcc 7937; nostoc sp. strains pcc 7413 and pcc 7107; calothrix sp. strain pcc 7601 (which is a mutant unable to develop heterocysts); and fischerella musc ...	1997	9006043
a hormogonium regulating locus, hrmua, of the cyanobacterium nostoc punctiforme strain atcc 29133 and its response to an extract of a symbiotic plant partner anthoceros punctatus.	transposon-generated mutant strain ucd 328 of nostoc punctiforme strain atcc 29133 has a phenotype of an increased sensitivity to a hormogonium-inducing factor exuded by a symbiotic plant partner, anthoceros punctatus, and an initial increased hormogonium-dependent infection of the plant. sequence analysis showed that the transposition site in strain ucd 328 lies within a 1,251-bp open reading frame (orf), designated hrma, that displays no significant similarity to known database sequences. a se ...	1997	9057333
effect of cadmium on the bioelement composition of nostoc uam208: interaction with calcium.		1997	9060371
uv-b-induced synthesis of photoprotective pigments and extracellular polysaccharides in the terrestrial cyanobacterium nostoc commune.	liquid cultures of the terrestrial cyanobacterium nostoc commune derived from field material were treated with artificial uv-b and uv-a irradiation. we studied the induction of various pigments which are though to provide protection against damaging uv-b irradiation. first, uv-b irradiation induced an increase in carotenoids, especially echinenone and myxoxanthophyll, but did not influence production of chlorophyll a. second, an increase of an extracellular, water-soluble uv-a/b-absorbing mycosp ...	1997	9068639
a polyketide-synthase-like gene is involved in the synthesis of heterocyst glycolipids in nostoc punctiforme strain atcc 29133.	a tn5-1063-derived mutant of nostoc punctiforme strain atcc 29133 was unable to fix n2 in air although it reduced acetylene in the absence of o2. mutant strain ucd 307 formed cells morphologically similar to heterocysts, but it failed to synthesize the characteristic heterocyst glycolipids. sequence analysis around the site of insertion revealed an orf of 3,159 base pairs, termed hgle. hgle putatively encodes a 115.4-kda protein containing two domains with conserved amino acid sequences identifi ...	1997	9075624
protein tyrosine phosphorylation in the cyanobacterium anabaena sp. strain pcc 7120.	components of a protein tyrosine phosphorylation/dephosphorylation network were identified in the cyanobacterium anabaena sp. strain pcc 7120. three phosphotyrosine (p-tyr) proteins of 27, 36, and 52 kda were identified through their conspicuous immunoreactions with rc20h monoclonal antibodies specific for p-tyr. these immunoreactions were outcompeted completely by free p-tyr (5 mm) but not by phosphoserine or phosphothreonine. the p-tyr content of the three major p-tyr proteins and several mino ...	1997	9079918
three new cryptophycins from nostoc sp. gsv 224.	cryptophycin 46 (2), -175 (3), and -176(4) have been identified as three new trace constituents of nostoc sp. gsv 224. cryptophycin-46 is an epimer of cryptophycin-3 (5) and to date is the only naturally occurring analogue having the s configuration at c-10 (c-2 in unit b). cryptophycins-175 and -176 also differ in unit b where 3 is the o-methyl analogue of cryptophycin-45 (6) and 4 is the o-desmethyl analogue of cryptophycin-21 (8). the relative and absolute stereochemistries of the three new a ...	1997	9090872
dechlorination of lindane by the cyanobacterium anabaena sp. strain pcc7120 depends on the function of the nir operon.	nitrate is essential for lindane dechlorination by the cyanobacteria anabaena sp. strain pcc7120 and nostoc ellipsosporum, as it is for dechlorination of other organic compounds by heterotrophic microorganisms. based on analyses of mutants and effects of environmental factors, we conclude that lindane dechlorination by anabaena sp. requires a functional nir operon that encodes the enzymes for nitrate utilization.	1997	9150239
discovery of cyanovirin-n, a novel human immunodeficiency virus-inactivating protein that binds viral surface envelope glycoprotein gp120: potential applications to microbicide development.	we have isolated and sequenced a novel 11-kda virucidal protein, named cyanovirin-n (cv-n), from cultures of the cyanobacterium (blue-green alga) nostoc ellipsosporum. we also have produced cv-n recombinantly by expression of a corresponding dna sequence in escherichia coli. low nanomolar concentrations of either natural or recombinant cv-n irreversibly inactivate diverse laboratory strains and primary isolates of human immunodeficiency virus (hiv) type 1 as well as strains of hiv type 2 and sim ...	1997	9210678
siderophore production in two species of nostoc as influenced by the toxicity of nitrophenolics.		1997	9211704
strain characterization and classification of oxyphotobacteria in clone cultures on the basis of 16s rrna sequences from the variable regions v6, v7, and v8.	a major problem in development of a polyphasic taxonomy is that the identification of oxyphotobacterial strains (cyanobacteria and prochlorophytes) in culture collections may be incorrect. we have therefore developed a diagnostic system using the dna sequence polymorphism in the 16s rrna regions v6 to v8 for individual strain characterization and identification. pcr primers amplifying v6 to v8 from oxyphotobacteria in unialgal cultures were constructed. direct solid-phase or cyclic sequencing wa ...	1997	9212409
rrna sequences and evolutionary relationships among toxic and nontoxic cyanobacteria of the genus microcystis.	a primary-structure analysis of the 16s rrna gene was performed with 10 strains representing five described and one unidentified species of the genus microcystis. the phylogenies determined illustrate the evolutionary affiliations among microcystis strains, other cyanobacteria, and related plastids and bacteria. a cluster of 10 strains that included hepatotoxic isolates identified as microcystis aeruginosa formed a monophyletic group. however, the genus microcystis appeared to be polyphyletic an ...	1997	9226902
ornithine cycle in nostoc pcc 73102: presence of an in vitro functional argininosuccinate lyase.	the presence of argininosuccinate lyase (asl), an enzyme catalyzing the final step of arginine biosynthesis, was demonstrated in the heterocystous cyanobacterium nostoc pcc 73102 by measuring in vitro enzyme activity and by visualization of asl in native protein gels. activity staining of a native page gel revealed one asl-dependent band with a molecular mass of about 240 kda. a colorimetric assay for asl based on the measurement of urea produced from arginine in the presence of an excess of arg ...	1997	9228773
isolation, primary sequence determination, and disulfide bond structure of cyanovirin-n, an anti-hiv (human immunodeficiency virus) protein from the cyanobacterium nostoc ellipsosporum.	a novel anti-hiv protein, cyanovirin-n (cv-n), was isolated from an aqueous cellular extract of the cultured cyanobacterium (blue-green alga) nostoc ellipsosporum, purified by reverse-phase hplc, and sequenced by n-terminal edman degradation of the intact protein and peptide fragments produced by endoproteinase digestions. cv-n consists of a single 101 amino acid chain which exhibits significant internal sequence duplication, but no significant homology to previously described proteins or to the ...	1997	9299483
characterization of cyanobacteria by sds-page of whole-cell proteins and pcr/rflp of the 16s rrna gene.	planktonic, filamentous cyanobacterial strains from different genera, both toxic and nontoxic strains, were characterized by sds-page of whole-cell proteins and pcr/rflp of the 16s rrna gene. total protein pattern analysis revealed the mutual relationships at the genus level. restriction fragment length polymorphism (rflp) of the 16s rrna gene with reference strains proved to be a good method for the cyanobacterial taxonomy. the nonheterocystous strains outgrouped from the nitrogen-fixing ones. ...	1997	9382701
purification and spectroscopic characterization of a recombinant chloroplastic hemoglobin from the green unicellular alga chlamydomonas eugametos.	hemoglobins (hb), which have the important task of delivering molecular oxygen by facilitating its reversible binding to the heme, are now thought to have evolved in all groups of organisms including prokaryotes, fungi, plants and animals. our recent finding of a light-inducible chloroplastic hb in the green unicellular alga chlamydomonas eugametos has further extend this idea, while raising questions about the function that an hb could play in a high oxygen environment such as in the chloroplas ...	1996	9022709
spectroscopical and functional characterization of the hemoglobin of nostoc commune (utex 584 (cyanobacterial).	structural analysis of a monomeric hemoglobin from the cyanobacterium nostoc commune strain utex 584, cyanoglobin (potts et al. (1992) science 256, 1690-1692), is presented. cyanoglobin binds molecular oxygen reversibly, with high oxygen affinity and non-cooperativity. there was no evidence for decreased stability of the pigment at 37 degrees c. cyanoglobin-specific antibodies showed no cross-reactivity with two reference hemoglobins, leghemoglobin a and sperm whale myoglobin. the absorption spe ...	1996	8547335
regulation of photosynthetic enzymes in light- or dark-grown cyanobacterium nostoc sp. mac.		1996	8878946
glbn (cyanoglobin) is a peripheral membrane protein that is restricted to certain nostoc spp.	the glbn gene of nostoc commune utex 584 is juxtaposed to nifu and nifh, and it encodes a 12-kda monomeric hemoglobin that binds oxygen with high affinity. in n. commune utex 584, maximum accumulation of glbn occurred in both the heterocysts and vegetative cells of nitrogen-fixing cultures when the rate of oxygen evolution was repressed to less than 25 micromol of o2 mg of chlorophyll a(-1) h(-1). accumulation of glbn coincided with maximum synthesis of nifh and ferredoxin nadp+ oxidoreductase ( ...	1996	8932316
transcriptional regulation of zwf, encoding glucose-6-phosphate dehydrogenase, from the cyanobacterium nostoc punctiforme strain atcc 29133.	the gene encoding glucose-6-phosphate dehydrogenase (g6pd), zwf, in nostoc punctiforme strain atcc 29133 is part of a four-gene operon that also encodes fructose bisphosphatase (fbp), transaldolase (tal) and a gene product termed opca, which is contranscribed with zwf and essential for g6pd activity. the effect of exogenous nitrogen and carbon sources on transcription of these genes was investigated. growth in the presence of ammonium yielded low levels of transcripts encoding all genes of the o ...	1996	8939431
reconstitution of the 2fe-2s center and g = 1.89 electron paramagnetic resonance signal into overproduced nostoc sp. pcc 7906 rieske protein.	the rieske 2fe-2s protein is a distinguishing subunit of the photosynthetic electron transport cytochrome b6f complex in chloroplast and cyanobacterial thylakoid membranes. we have constructed plasmids for overproduction in escherichia coli of fusion, full-length, and truncated forms of the rieske (petc) protein from the cyanobacterium nostoc sp. pcc 7906. a glutathione s-transferase/rieske fusion protein was used to prepare specific chicken egg-yolk antibodies against the rieske protein. expres ...	1996	8952502
the devr gene product is characteristic of receivers of two-component regulatory systems and is essential for heterocyst development in the filamentous cyanobacterium nostoc sp. strain atcc 29133.	strain ucd 311 is a transposon-induced mutant of nostoc sp. strain atc c 29133 that is unable to fix nitrogen in air but does so under anoxic conditions and is able to establish a functional symbiotic association with the hornwort anthoceros punctatus. these properties of strain ucd 311 are consistent with previous observations that protection against oxygen inactivation of nitrogenase is physiologically provided within a. punctatus tissue. upon deprivation of combined nitrogen, strain ucd 311 c ...	1996	8606181
transaldolase genes from the cyanobacteria anabaena variabilis and synechocystis sp. pcc 6803: comparison with other eubacterial and eukaryotic homologues.	we have sequenced and analysed the transaldolase (tal) genes from two cyanobacteria, anabaena variabilis (atcc 29413) and synechocystis sp. pcc 6803, which are filamentous heterocyst-forming and unicellular organisms, respectively. the deduced amino acid sequences of the two cyanobacterial tal genes are 78% identical and are highly homologous to both eubacterial and eukaryotic transaldolases (escherichia coli, two yeasts, and man) with values ranging from 54 to 60% amino acid identity. in contra ...	1996	8616240
geosiphon pyriforme, a fungus forming endocytobiosis with nostoc (cyanobacteria), is an ancestral member of the glomales: evidence by ssu rrna analysis.	geosiphon pyriforme inhabiting the surface of humid soils represents the only known example of endocytobiosis between a fungus (zygomycotina; macrosymbiont) and cyanobacteria (nostoc; endosymbiont). in order to elucidate the taxonomical and evolutionary relationship of geosiphon pyriforme to fungi forming arbuscular mycorrhiza (am fungi), the small-subunit (ssu) ribosomal rna genes of geosiphon pyriforme and glomus versiforme (glomales; a typical am fungus) were analyzed and aligned with ssu rrn ...	1996	8660431
ca2+ uptake and its regulation in the cyanobacterium nostoc mac	the uptake of ca2+ and its regulation in the cyanobacterium nostoc mac were investigated. cation uptake pattern was found to be biphasic, consisting of (a) rapid binding of cations to the negatively charged cell surface and (b) its metabolism dependent on intracellular import at least up to 60 min with the saturation at 2 mm ca2+ (km, 1.5 mm, vmax 42.1 nmol ca2+ mg-1 protein min-1 ). the cellular ca2+ uptake was light and atp dependent, and the addition of 3(3,4-dichlorophenyl)-1,1-dimethyl urea ...	1996	8661678
impact of aluminium, fluoride and fluoroaluminate complex on atpase activity of nostoc linckia and chlorella vulgaris.	this study demonstrates a ph-dependent inhibition of mg(2+)- and ca(2+)-atpase activities of nostoc linckia and chlorella vulgaris exposed to alcl3, alf3, naf and alcl3+naf together. alf3 and the combination of alcl3+naf were more inhibitory to both the enzymes as compared with alcl3 and naf. toxicity of the test compounds increased with increasing acidity. interaction of alcl3+naf was additive on n. linckia and c. vulgaris, respectively, at ph 7.5 and 6.8, and synergistic at ph 6.0 and 4.5. in ...	1996	8696079
cyclic peptides and depsipeptides from cyanobacteria: a review.	an elaborate array of structurally-novel and biologically-active cyclic peptides and depsipeptides are found in blue-green algae (cyanobacteria). several of these compounds possess structures that are similar to those of natural products from marine invertebrates. most of these cyclic peptides and depsipeptides, such as the microcystins and the lyngbyatoxins, will probably only be useful as biochemical research tools. a few, however, have the potential for development into useful commercial prod ...	1996	8730577
heterocyst formation.	heterocysts are microaerobic, n2-fixing cells that form in a patterned array within o2-producing filamentous cyanobacteria. structural features of heterocysts can be predicted from consideration of their physiology. this review focuses on the spacing mechanism that determines which cells will differentiate, and on the regulation of the progression of the differentiation process. applicable genetic tools, developed primarily using anabaena pcc 7120, but employed also with nostoc spp., are reviewe ...	1996	8982449
promiscuity of heme groups in the cyanobacterial cytochrome-c oxidase.	the cyanobacteria nostoc sp. strain mac, anabaena 7937, synechocystis 6803, and anacystis nidulans (synechococcus 6301) were grown and incubated in the light under three different oxygen regimes: phase-a cells were harvested from photoautotrophically growing cultures at a cell density of 2.8-3.2 microliter packed cell mass/ml and an oxygen concentration of approx. 350 microm (corresponding to > 150% air saturation). phase-b cells were harvested 24 hrs after 20 microm 3-(3,4-dichlorophyl)-1,1-dim ...	1995	8747548
interaction of cryptophycin 1 with tubulin and microtubules.	the cryptophycins are newly discovered antimitotic agents isolated from the cyanobacterium nostoc. previous studies using cultured cells demonstrated that microtubules are the target of these compounds. we have studied the interaction of cryptophycin 1 with tubulin and microtubules in vitro. cryptophycin 1 is an effective inhibitor of tubulin polymerization, causes tubulin to aggregate, and depolymerizes microtubules to linear polymers somewhat similar to the spiral-like structures produced by t ...	1995	8543019
nucleotide sequence of an operon in nostoc sp. strain atcc 29133 encoding four genes of the oxidative pentose phosphate cycle.		1995	7870816
structure and evolution of paramecium hemoglobin genes.	hemoglobin (hb) genes have been cloned from three different species of ciliated protists, p. multimicronucleatum, p. triaurelia and p. jenningsi. southern blotting of the genomic dnas using the p. caudatum hb cdna showed both intraspecies variation in different stocks of p. caudatum and interspecies variation within the genus paramecium. the isolated hb genes were composed of 118, 117 and 117 codons, and interrupted by a short intron with 27, 29 and 29 bp at the same position, in p. multimicronu ...	1995	7578257
two heterocyst-specific dna rearrangements of nif operons in anabaena cylindrica and nostoc sp. strain mac.	two site-specific dna rearrangements occur during heterocyst differentiation in the cyanobacterium anabaena sp. strain pcc 7120: the deletion of an 11 kb element from within the nifd gene and the deletion of a 55 kb element from within the fdxn gene. three nostoc and six anabaena strains were screened for the presence of the nifd and fdxn elements by southern hybridization with anabaena pcc 7120 dna probes. eight of the nine strains contained dna sequences that were similar to the nifd element. ...	1995	7582007
characterization of toxin-producing cyanobacteria by using an oligonucleotide probe containing a tandemly repeated heptamer.	cyanobacteria produce toxins that kill animals. the two main classes of cyanobacterial toxins are cyclic peptides that cause liver damage and alkaloids that block nerve transmission. many toxin-producing strains from finnish lakes were brought into axenic culture, and their toxins were characterized. restriction fragment length polymorphism analysis, probing with a short tandemly repeated dna sequence found at many locations in the chromosome of anabaena sp. strain pcc 7120, distinguishes hepato ...	1995	7592362
genetic evidence of a major role for glucose-6-phosphate dehydrogenase in nitrogen fixation and dark growth of the cyanobacterium nostoc sp. strain atcc 29133.	heterocysts, sites of nitrogen fixation in certain filamentous cyanobacteria, are limited to a heterotrophic metabolism, rather than the photoautotrophic metabolism characteristic of cyanobacterial vegetative cells. the metabolic route of carbon catabolism in the supply of reductant to nitrogenase and for respiratory electron transport in heterocysts is unresolved. the gene (zwf) encoding glucose-6-phosphate dehydrogenase (g6pd), the initial enzyme of the oxidative pentose phosphate pathway, was ...	1995	7592384
characterization of ts-mutants of cyanophage n-1 by their inactivation by physical and chemical agents.	the effect of temperature, ultraviolet (uv) light and ethylenediaminetetraacetic acid (edta) on the stability of cyanophage n-1, infecting the cyanobacterium nostoc muscorum was studied. complete inactivation of the phage occurred at 60 degrees c in 6 mins. all the temperature-sensitive (ts) mutants exhibited faster inactivation at 50 degrees c than the wild type. uv light readily inactivated the particles of the wild giving a survival of 3.44% at a dose of 60 secs. all the ts-mutants were found ...	1995	7676938
structure of a novel oligosaccharide-mycosporine-amino acid ultraviolet a/b sunscreen pigment from the terrestrial cyanobacterium nostoc commune.	water-soluble uv-a/b-absorbing pigments are secreted by cells of the cosmopolitan terrestrial cyanobacterium nostoc commune. the pigments constitute a complex mixture of monomers with molecular masses of up to 1801 da. two different chromophores with absorption maxima at 312 and 335 nm are linked to different amino acids and to oligosaccharides consisting of galactose, glucose, xylose, glucuronic acid, and glucosamine. the 335 nm chromophore is a 1,3-diaminocyclohexen derivative, while the chrom ...	1995	7721752
growth and some physiological aspects of nostoc muscorum in response to mixtures of two triazine herbicides.		1995	7742636
multiple metal resistance in the cyanobacterium nostoc muscorum.		1995	7767039
plasmid and chromosomal dna recovery by electroextraction of cyanobacteria.	high voltage electroporation has been investigated as a method for rapid recovery of plasmid and chromosomal dna from the cyanobacteria nostoc pcc 7121, synechococcus pcc 7002, and anabaena pcc 7120. pulses of 18 kv/cm and higher applied to concentrated nostoc cells carrying a shuttle plasmid (prl25) resulted in copious release of nucleic acids and phycobiliproteins into the suspending medium. small portions of these supernatants, when electroporated with escherichia coli, gave rise to hundreds ...	1995	7781980
effective concentrations of nitrophenolics toward growth yield of selected microalgae and cyanobacteria isolated from soil.	the effective concentrations (ec), which cause a certain percentage of inhibition in growth yield, of four nitrophenolics (o-nitrophenol, m-nitrophenol, p-nitrophenol (pnp), and 2,4-dinitrophenol) and the major metabolites of pnp reduction (p-nitrosophenol and p-aminophenol) toward growth of two microalgae (chlorella vulgaris and scenedesmus bijugatus) and two cyanobacteria (nostoc muscorum and nostoc linckia), all isolated from soil, were determined following linear regression analysis. the ec5 ...	1995	8964245
factors regulating methyl mercury uptake in a cyanobacterium.	the simultaneous addition of dithiothreitol (dtt), mercaptoethanol, and glutathione (30 microm each) and ch3hg+ to nostoc calcicola cells reduced ch3hg+ uptake in the order gsh > dtt > mercaptoethanol. however, the preexposure of cyanobacterial cells to similar thiols resulted in different pattern of ch3hg+ uptake in the sequence: gsh > mercaptoethanol > dtt. light-grown cyanobacterial cells demonstrated a faster initial uptake of ch3hg+ (rate 0.619 mumol ch3hg+ mg-1 protein min-1, 10 min) with ...	1995	8565882
disintegration of phycobilisomes in a rice field cyanobacterium nostoc sp. following uv irradiation.	the effects of ultraviolet-b (uv-b, 280-315 nm) irradiation on survival, growth and phycobilisome assembly have been studied in the n2-fixing cyanobacterium nostoc sp. survival and growth were virtually arrested after 120 min of uv irradiation. the phycobiliprotein fractions showed a decrease in absorption and fluorescence as well as a shift towards shorter wavelengths indicating the impairment of energy transfer from phycobiliproteins to the photosynthetic reaction centers. this was further sup ...	1995	8589643
desiccation tolerance of prokaryotes.	the removal of cell-bound water through air drying and the addition of water to air-dried cells are forces that have played a pivotal role in the evolution of the prokaryotes. in bacterial cells that have been subjected to air drying, the evaporation of free cytoplasmic water (vf) can be instantaneous, and an equilibrium between cell-bound water (vb) and the environmental water (vapor) potential (psi wv) may be achieved rapidly. in the air-dried state some bacteria survive only for seconds where ...	1994	7854254
cadmium mediated control of nitrogenase activity and other enzymes in a nitrogen fixing cyanobacterium.	cadmium decreased the specific growth rate and total cell mass at concentrations > 0.001 micrograms ml-1. it also reduced heterocyst frequency, total cell protein, nitrogenase activity (acetylene reduction) and decreased glutamine synthetase (gs) and glutamate synthase (gogat) activities. however, cells grown under low concentration of cadmium (0.001 microgram ml-1) had enhanced nitrogenase as well as gs activity besides showing increased growth rate and heterocyst frequency. cadmium has apparen ...	1994	7866728
transposon mutagenesis of nostoc sp. strain atcc 29133, a filamentous cyanobacterium with multiple cellular differentiation alternatives.	nostoc sp. strain atcc 29133 (pcc 73102; nostoc 29133) is a symbiotically-competent, facultatively heterotrophic, diazotrophic cyanobacterium with the capacity to differentiate specialized cells such as heterocysts, akinetes and hormogonial filaments. we have optimized several methods for physiological and molecular genetic analysis of nostoc 29133. by use of a tn5 derivative, tn5-1063 (km(r)bm(r)sm(r)), delivered by conjugation from escherichia coli, antibiotic-resistant mutants of nostoc 29133 ...	1994	7881544
sequence of a 2.6-kb cryptic plasmid from a marine cyanobacterium synechococcus sp.	we have shown previously that the copy number of plasmid psy10 from the marine cyanobacterium synechococcus sp. nkbg 042902 is dependent on the salinity of the growth medium. we report here the complete nucleotide sequence (2561 bp) of this plasmid. the longest open reading frame, orf-b (1.08 kb), occurs on a 1.6-kb ecori fragment. this orf encodes a putative protein which is 360 aa residues in length and is 37.8% homologous to the replication protein of plasmid pca2.4 from synechocystis sp. str ...	1994	7899510
biochemical effects of carbaryl on nitrogen assimilating enzymes of cyanobacteria nostoc muscorum.		1994	7912573
cryptophycin: a new antimicrotubule agent active against drug-resistant cells.	cryptophycin is a cytotoxic dioxadiazacyclohexadecenetetrone isolated from cyanobacteria of the genus nostoc. incubation of l1210 leukemia cells with cryptophycin resulted in dose-dependent inhibition of cell proliferation in parallel with increases in the percentage of cells in mitosis (half-maximal effects at < 10 pm). indirect immunofluorescence studies demonstrated that treatment of a-10 vascular smooth muscle cells with cryptophycin results in marked depletion of cellular microtubules and r ...	1994	7913408
cloning and nucleotide sequence of the gene encoding dinitrogenase reductase (nifh) from the cyanobacterium nostoc 6720.	the nucleotide sequence of the 3' end of the nifu coding sequence, the complete coding sequence of nifh and a substantial part of the 5' end of nifd coding sequence from nostoc 6720 is presented. the coding sequences are highly conserved with those of anabaena 7120 and anabaena sp. l31. however the intergenic region between nifu and nifh contains two segments of short tandemly repetitive repeat sequences (strrs) that differ from the strr that is common to both anabaena7120 and anabaenasp. l31. v ...	1994	7918657
two mutations that block heterocyst differentiation have different effects on akinete differentiation in nostoc ellipsosporum.	evident differentiation of vegetative cells into heterocysts in anabaena sp. strain pcc 7120 is prevented by insertions in genes hetr and hetp. nostoc ellipsosporum possesses single copies of genes that hybridize with hetr and hetp. in mutant ne2 of n. ellipsosporum, in which hetr is interrupted by an insert, and in a double recombinant of wild-type n. ellipsosporum with a plasmid that bears an interrupted copy of hetr, neither heterocysts nor akinetes are formed. when an intact copy of hetr fro ...	1994	7934891
mutational analysis of the nh4+-nitrogen controls that regulate ammonium transport activity, heterocyst differentiation, nitrogenase activity and the heterocyst-spacing pattern in the cyanobacterium nostoc muscorum.	mutational analysis of the genetic determinants mediating nh(4+)-nitrogen regulating effects on nh(4+)-transport activity, heterocyst differentiation, nitrogenase activity and heterocyst pattern formation was carried out in nostoc muscorum. evidence suggested the operation of three separate genetic determinants in such nitrogen control; one mediating nh(4+)-repression control on both heterocyst formation and nh(4+)-transport activity, a second (nif-r) mediating nh(4+)-repression control on nitro ...	1994	8019441
athermal physiological effects of microwaves on a cynobacterium nostoc muscorum: evidence for em-memory bits in water.	athermal physiological effects of continuous wave and modulated microwaves were studied on a cynobacterium nostoc muscorum. the study shows that different microwave frequencies in continuous wave and modulated modes produced significantly different physiological effects on the algae. water-mediated bioeffects further present additional proof that water has the capability to remember the imposed electromagnetic field characteristics for an extended period of time.	1994	8022214
analysis of the sequences within and flanking the cyanoglobin-encoding gene, glbn, of the cyanobacterium nostoc commune utex 584.	a 3.5-kb segment of dna containing nifu glbn nifh nifd was cloned from a gene library of nostoc 584 and sequenced. the nifu-glbn intergenic region contains short tandemly repeated repetitive sequences (5'-aattacg). a sequence corresponding to a nifa-like upstream activator sequence (with the consensus recognition sequence for bifa in anabaena 7120), elements of a nifh promoter and a sequence that may function as a transcription terminator, were identified downstream from glbn. glbn, unique to ce ...	1994	8063099
isolation and characterization of temperature-sensitive mutants of cyanophage n-1.	optimal conditions for the induction of temperature-sensitive (ts) mutants of cyanophage n-1 were established after mutagenesis with n-methyl-n'-nitro-n-nitrosoguanidine (mnng). a treatment with mnng (400 micrograms/ml) for 2 hrs at ph 8.0 induced ts-mutants at a maximum frequency of 1.46 x 10(-3). a characterization of 10 such ts-mutants with regard to adsorption, one-step growth and temperature-shift experiments with nostoc muscorum as host bacterium led to the identification of temperature-se ...	1994	8067307
energetics of cyanophage n-1 multiplication in the diazotrophic cyanobacterium nostoc muscorum.	cyanophage n-1 multiplication was investigated during the latent period of the virus, when 14co2 fixation was inhibited whereas respiratory o2 uptake increased approximately 67% at 4 h after infection. a simultaneous decrease (70%) in the glycogen content of infected cells indicated its catabolic involvement. a chloramphenicol-sensitive rise in glucose-6-phosphate dehydrogenase activity as a result of n-1 infection partly explained the increase in aerobic respiration. the total atp pool declined ...	1994	8078415
the gene encoding cytochrome-c oxidase subunit i from synechocystis pcc6803.	the gene (coxi or coxa) encoding subunit i (coi) of cytochrome-c oxidase (cytochrome aa3) of synechocystis pcc6803, synechococcus pcc7942 (anacystis nidulans r2) and nostoc pcc8002 (nostoc mac), was identified by heterologous hybridization of chromosomal digests with a 17-bp oligodeoxyribonucleotide (probe c) derived from the coxi of paracoccus denitrificans. a single genomic fragment was found to bind to probe c in all chromosomal digests. due to its favorable signal-to-noise ratio, the genome ...	1994	8125290
water stress proteins of nostoc commune (cyanobacteria) are secreted with uv-a/b-absorbing pigments and associate with 1,4-beta-d-xylanxylanohydrolase activity.	acidic water stress polypeptides (wsp) with molecular masses of 33, 37 and 39 kda are the most abundant soluble proteins in the cyanobacterium nostoc commune. wsp polypeptides and uv-a/b-absorbing pigments are secreted by cells, accumulate in the extracellular glycan sheath, and are released from desiccated colonies upon rehydration. no evidence was obtained for either glycosylation, phosphorylation, or acylation of wsp polypeptides. nh2-terminal amino acid sequences of the 33-, 37-, and 39-kda ...	1994	8125999
hypocholesterolemic effect of blue-green alga, ishikurage (nostoc commune) in rats fed atherogenic diet.	blue-green alga, nostoc commune is rich in dietary fiber. to examine the hypocholesterolemic effect, the alga or the dietary fibers were given to the rats fed cholesterol diet. serum cholesterol elevation was significantly depressed in those rats. cholesterol increased in the liver of rats given the alga and the fiber. the content of fecal cholesterol and bile acid unchanged. of the dietary fibers, oxalate-oxalic acid soluble substance (ooss) found abundant in the alga was most effective in lowe ...	1994	8146104
detection and characterization of cyanobacterial nifh genes.	the dna sequence of a 359-bp fragment of nifh was determined for the heterocystous strains anabaena sp. strain ca (atcc 33047), nostoc muscorum utex 1933, a nostoc sp., gloeothece sp. strain atcc 27152, lyngbya lagerheimii utex 1930, and plectonema boryanum iu 594. results confirmed that the dna sequence of the 359-bp segment is sufficiently variable to distinguish cyanobacterial nifh genes from other eubacterial and arachaeobacterial nifh genes, as well as to distinguish heterocystous from nonh ...	1994	8161180