Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| effects of three pesticides on the growth, photosynthesis and photoinhibition of the edible cyanobacterium ge-xian-mi (nostoc). | effects of butachlor, bensulfuron-methyl, and dimethoate on the growth, photosynthesis, and photoinhibition of the edible cyanobacterium ge-xian-mi were examined in order to gain insight into the relationship between its productivity reduction and the abusive use of pesticides in the field. severe inhibition of growth was found in the presence of four- to six-fold field concentration of butachlor and very high concentrations of bensulfuron-methyl and dimethoate. mild stimulation of photosynthesi ... | 2007 | 17258325 |
| high cyanobiont selectivity of epiphytic lichens in old growth boreal forest of finland. | here, cyanobiont selectivity of epiphytic lichen species was examined in an old growth forest area in finland. samples of the eight lichen species were collected from the same aspen (populus tremula) and adjacent aspens in the same stand. the cyanobionts of these samples were compared with free and symbiotic nostoc obtained from other habitats and geographic regions. our results, based on the phylogenetic analysis of a partial small subunit of the ribosomal dna (16s rdna) and the rbclx gene comp ... | 2007 | 17244057 |
| allosteric activation by dimerization of the pknd receptor ser/thr protein kinase from mycobacterium tuberculosis. | to define how extracellular signals activate bacterial receptor ser/thr protein kinases, we characterized the regulatory functions of a weak dimer interface identified in the mycobacterium tuberculosis pknb and pkne receptor kinases. sequence comparisons revealed that the analogous interface is conserved in pknd orthologs from diverse bacterial species. to analyze the roles of dimerization, we constructed m. tuberculosis pknd kinase domain (kd) fusion proteins that formed dimers upon addition of ... | 2007 | 17242402 |
| discovery of two cyanobacterial phenylalanine ammonia lyases: kinetic and structural characterization. | phenylalanine ammonia lyase (pal) catalyzes the deamination of phenylalanine to cinnamate and ammonia. while pals are common in terrestrial plants where they catalyze the first committed step in the formation of phenylpropanoids, only a few prokaryotic pals have been identified to date. here we describe for the first time pals from cyanobacteria, in particular, anabaena variabilis atcc 29413 and nostoc punctiforme atcc 29133, identified by screening the genome sequences of these organisms for me ... | 2007 | 17240984 |
| the specificity in the interaction between cytochrome f and plastocyanin from the cyanobacterium nostoc sp. pcc 7119 is mainly determined by the copper protein. | the plastocyanin-cytochrome f complex from nostoc exhibits relevant structural differences when compared with the homologous complexes from other cyanobacteria and plants, with electrostatic and hydrophobic interactions being differently involved in each case. here, five negatively charged residues of a recombinant form of cytochrome f from nostoc have been replaced with either neutral or positively charged residues, and the effects of mutations on the kinetics of electron transfer to wild-type ... | 2007 | 17240983 |
| biosynthetic characterization and chemoenzymatic assembly of the cryptophycins. potent anticancer agents from cyanobionts. | the lichen cyanobacterial symbiont nostoc sp. atcc 53789 and its close relative nostoc sp. gsv 224 are prolific producers of natural products, generating >25 derivatives of the cryptophycin class of secondary metabolites. cryptophycin 1, the prototypic member of the class, is a potent tubulin-depolymerizing agent, and several semisynthetic derivatives are being developed as anticancer therapeutics. here we provide a detailed characterization of the cryptophycin metabolic pathway by stable-isotop ... | 2006 | 17240975 |
| carbon cycling in anabaena sp. pcc 7120. sucrose synthesis in the heterocysts and possible role in nitrogen fixation. | nitrogen (n) available to plants mostly originates from n(2) fixation carried out by prokaryotes. certain cyanobacterial species contribute to this energetically expensive process related to carbon (c) metabolism. several filamentous strains differentiate heterocysts, specialized n(2)-fixing cells. to understand how c and n metabolism are regulated in photodiazotrophically grown organisms, we investigated the role of sucrose (suc) biosynthesis in n(2) fixation in anabaena sp. pcc 7120 (also know ... | 2007 | 17237189 |
| trans protein splicing of cyanobacterial split inteins in endogenous and exogenous combinations. | inteins are autocatalytic protein domains that post-translationally excise from protein precursors and ligate their flanking regions with a peptide bond, in a process called protein splicing. intein-containing dna polymerases of cyanobacteria and nanoarchaea are naturally split into two separate genes at their intein domain. such naturally occurring split inteins rapidly self-associate and reconstitute protein-splicing activity in trans. here, we analyze the in vitro protein-splicing activity of ... | 2007 | 17198403 |
| peptide macrocyclization: the reductase of the nostocyclopeptide synthetase triggers the self-assembly of a macrocyclic imine. | many biologically active natural products have macrocyclic structures. in nonribosomal peptides macrocyclization is commonly achieved via the formation of intramolecular ester or amide bond catalyzed by thioesterase domains during biosynthesis. a unique and so far unknown type of peptide cyclization occurs in the nostocyclopeptide, a macrocyclic imine produced by the terrestrial cyanobacterium nostoc sp. atcc53789. in this work we show that a c-terminal reductase domain of the nostocyclopeptide ... | 2006 | 17177378 |
| rare group i intron with insertion sequence element in a bacterial ribonucleotide reductase gene. | a rare group i intron in a cyanobacterial ribonucleotide reductase gene has been characterized. it contains a mobile insertion sequence element not required for rna splicing. ribonucleotide reductase genes were found to be hot spots for all three types of self-splicing intervening sequences, including group i and ii introns and inteins. | 2007 | 17172330 |
| high photobiological hydrogen production activity of a nostoc sp. pcc 7422 uptake hydrogenase-deficient mutant with high nitrogenase activity. | we describe a strategy to establish cyanobacterial strains with high levels of h(2) production that involves the identification of promising wild-type strains followed by optimization of the selected strains using genetic engineering. nostoc sp. pcc 7422 was chosen from 12 other heterocystous strains, because it has the highest nitrogenase activity. we sequenced the uptake hydrogenase (hup) gene cluster as well as the bidirectional hydrogenase gene cluster from the strain, and constructed a muta ... | 2007 | 17131047 |
| a bacterial dynamin-like protein. | dynamins form a superfamily of large mechano-chemical gtpases that includes the classical dynamins and dynamin-like proteins (dlps). they are found throughout the eukarya, functioning in core cellular processes such as endocytosis and organelle division. many bacteria are predicted by sequence to possess large gtpases with the same multidomain architecture that is found in dlps. mechanistic dissection of dynamin family members has been impeded by a lack of high-resolution structural data current ... | 2006 | 17122778 |
| studies on poly-beta-hydroxybutyrate synthase activity of nostoc muscorum. | this study compares the phb synthase activity of nostoc muscorum, a n(2)-fixing cyanobacterium under control (grown in usual bg-11 medium), nitrogen (n) and phosphorus (p) deprivation and chemoheterotrophic conditions. specific activity of phb synthase did not depict significant variations in the latter three types of cultures, except for the control one, where a significantly lower activity was recorded. phb synthase activity was detected only in the soluble fractions of both the control as wel ... | 2006 | 17116969 |
| the atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by xas. | the transient complex between cytochrome f and plastocyanin from the cyanobacterium nostoc sp. pcc 7119 has been analysed by x-ray absorption spectroscopy in solution, using both proteins in their oxidized and reduced states. fe k-edge data mainly shows that the atypical metal coordination geometry of cytochrome f, in which the n-terminal amino acid acts as an axial ligand of the heme group, remains unaltered upon binding to its redox partner, plastocyanin. this fact suggests that cytochrome f p ... | 2006 | 17111237 |
| characterization of the nitrate-nitrite transporter of the major facilitator superfamily (the nrtp gene product) from the cyanobacterium nostoc punctiforme strain atcc 29133. | the products of the npr1527 and npr1526 genes of the filamentous, diazotrophic, fresh-water cyanobacterium nostoc punctiforme strain atcc 29133 were identified as a nitrate transporter (nrt) and nitrate reductase (nr) respectively, by complementation of nitrate assimilation mutants of the cyanobacterium synechococcus elongatus strain pcc 7942. while other fresh-water cyanobacteria, including s. elongatus, have an atp-binding cassette (abc)-type nrt, the nrt of n. punctiforme belongs to the major ... | 2006 | 17090931 |
| functional and phylogenetic properties of the pore-forming beta-barrel transporters of the omp85 family. | beta-barrel-shaped channels of the omp85 family are involved in the translocation or assembly of proteins of bacterial, mitochondrial, and plastidic outer membranes. we have compared these proteins to understand the evolutionary development of the translocators. we have demonstrated that the proteins from proteobacteria and mitochondria have a pore diameter that is at least five times smaller than found for the omp85 in cyanobacteria and plastids. this finding can explain why omp85 from cyanobac ... | 2007 | 17088246 |
| a soluble 3d lc/ms/ms proteome of the filamentous cyanobacterium nostoc punctiforme. | nostoc punctiforme is an oxygenic photoautotrophic cyanobacterium with multiple developmental states, which can form nitrogen-fixing symbioses with a variety of terrestrial plants. 3d lc/ms/ms shotgun peptide sequencing was used to analyze the proteome when n. punctiforme is grown in continuous moderate light with ammonia as the nitrogen source. the soluble proteome includes 1575 proteins, 50% of which can be assigned to core metabolic and transport functions. another 39% are assigned to protein ... | 2006 | 17081061 |
| protein expression profiles in an endosymbiotic cyanobacterium revealed by a proteomic approach. | molecular mechanisms behind adaptations in the cyanobacterium (nostoc sp.) to a life in endosymbiosis with plants are still not clarified, nor are the interactions between the partners. to get further insights, the proteome of a nostoc strain, freshly isolated from the symbiotic gland tissue of the angiosperm gunnera manicata linden, was analyzed and compared with the proteome of the same strain when free-living. extracted proteins were separated by two-dimensional gel electrophoresis and were i ... | 2006 | 17073307 |
| microbial communities on glacier surfaces in svalbard: impact of physical and chemical properties on abundance and structure of cyanobacteria and algae. | microbial communities occurring in three types of supraglacial habitats--cryoconite holes, medial moraines, and supraglacial kames--at several glaciers in the arctic archipelago of svalbard were investigated. abundance, biovolume, and community structure were evaluated by using epifluorescence microscopy and culturing methods. particular emphasis was laid on distinctions in the chemical and physical properties of the supraglacial habitats and their relation to the microbial communities, and quan ... | 2006 | 17072679 |
| transient binding of plastocyanin to its physiological redox partners modifies the copper site geometry. | the transient complexes of plastocyanin with cytochrome f and photosystem i are herein used as excellent model systems to investigate how the metal sites adapt to the changes in the protein matrix in transient complexes that are involved in redox reactions. thus, both complexes from the cyanobacterium nostoc sp. pcc 7119 (former anabaena sp. pcc 7119) have been analysed by x-ray absorption spectroscopy. our data are consistent with a significant distortion of the trigonal pyramidal geometry of t ... | 2006 | 17064694 |
| engineered cyanophycin synthetase (cpha) from nostoc ellipsosporum confers enhanced cpha activity and cyanophycin accumulation to escherichia coli. | the cyanophycin (cgp) synthetase gene (cphane1) of the transposon-induced argl mutant ne1 of the cyanobacterium nostoc ellipsosporum, which exhibits a cgp-leaky phenotype during diazotrophical growth, was cloned and expressed in escherichia coli strain top10. its amino acid sequence exhibited high similarities to cphas of other cyanobacteria. recombinant cells of e. coli, which harbored a fragment comprising the complete cphane1 gene plus 400 bp of its downstream region in colinear orientation t ... | 2006 | 17012590 |
| allergenicity of airborne cyanobacteria phormidium fragile and nostoc muscorum. | in recent times, airborne microorganisms and their constituents have become prominent safety and health concern. ongoing climatic changes coupled with unwarranted human activities have significantly deteriorated the ambient air quality. in certain environments, airborne algae contribute significantly to the total biological load of the atmosphere, hitherto dominated by bacteria and fungi. present study was aimed to investigate the allergenic potency of two frequent viable algal forms i.e., phorm ... | 2008 | 17011621 |
| metabolites produced by cyanobacteria belonging to several species of the family nostocaceae. | this paper provides a comprehensive overview of metabolites, including lipids and lipid-like compounds, nitrogen metabolites, oligopeptides and amino acid derivatives, produced by cyanobacteria of the genera anabaenopsis, aphanizomenon, aulosira, cylindrospermopsis, cylindrospermum, nodularia, and richelia of the family nostocaceae. | 2006 | 17004647 |
| identification of a diagnostic marker to detect freshwater cyanophages of filamentous cyanobacteria. | cyanophages are viruses that infect the cyanobacteria, globally important photosynthetic microorganisms. cyanophages are considered significant components of microbial communities, playing major roles in influencing host community diversity and primary productivity, terminating cyanobacterial water blooms, and influencing biogeochemical cycles. cyanophages are ubiquitous in both marine and freshwater systems; however, the majority of molecular research has been biased toward the study of marine ... | 2006 | 16957185 |
| three putative photosensory light, oxygen or voltage (lov) domains with distinct biochemical properties from the filamentous cyanobacterium anabaena sp. pcc 7120. | light, oxygen or voltage (lov) domains function as blue-light sensors in the phototropin family of photoreceptors found in plants, algae and bacteria. we detected putative lov domains (alr3170-lov, all2875-lov and alr1229-lov) in the genome of a filamentous cyanobacterium, anabaena sp. pcc 7120. these cyanobacterial lov domains are closely clustered with the known lov domains. alr3170-lov and a112875-lov carry the conserved cysteine residue unique to the photoactive lov, whereas alr1229-lov does ... | 2006 | 16922605 |
| identification of carotenoid cleavage dioxygenases from nostoc sp. pcc 7120 with different cleavage activities. | carotenoid cleavage dioxygenases (ccds) are a class of enzymes that oxidatively cleave carotenoids into apocarotenoids. dioxygenases have been identified in plants and animals and produce a wide variety of cleavage products. despite what is known about apocarotenoids in higher organisms, very little is known about apocarotenoids and ccds in microorganisms. this study surveyed cleavage activities of ten putative carotenoid cleavage dioxygenases from five different cyanobacteria in recombinant esc ... | 2006 | 16920703 |
| mycobacterium tuberculosis transporter mmpl7 is a potential substrate for kinase pknd. | the mycobacterium tuberculosis serine/threonine protein kinases are attractive potential drug targets, and protein kinase d (pknd) is particularly interesting, as it is autophosphorylated on 11 residues, binds proteins containing forkhead associated domains, and contains a beta-propeller motif that likely functions as an anchoring sensor domain. we created a pknd knockout of a clinical m. tuberculosis isolate, and found that on in vitro phosphorylation of cell wall fractions it lacked a family o ... | 2006 | 16879801 |
| screening of microalgae for species excreting norharmane, a manifold biologically active indole alkaloid. | a screening of microalgae strains is described, with the objective to discover more species besides the known cyanobacterium nodularia harveyana which excrete the manifold biologically active and co-mutagenic indole alkaloid norharmane (9h-pyrido(3,4-b)indole) into their environment. seven more cyanobacterial species, anabaena cylindrica, anabaena inaequalis, anabaenopsis siamensis, chroococcus minutus, nostoc carneum, nostoc commune and phormidium foveolarum, were newly discovered. the norharma ... | 2008 | 16872816 |
| auxotrophic mutant of the cyanobacterium nostoc muscorum showing absolute requirement of cs+ or rb+ for diazotrophy and autotrophy. | caesium-resistant (cs(+)-r) mutant clones of the cyanobacterium nostoc muscorum were characterized for diazotrophic growth in a medium devoid of cs(+) or rb(+) or both. cs(+)-r phenotype suffered severe genetic damage of a pleiotropic nature affecting diazotrophic growth, chlorophyll a content, nitrogenase activity and photosynthetic o(2) evolution. mutation leading to development of cs(+)-r phenotype could be overcome by availability of cs(+)/rb(+). parent and mutant strains were similar with r ... | 2006 | 16847829 |
| genetically modified cyanobacterium nostoc muscorum overproducing proline in response to salinity and osmotic stresses. | in the parent nostoc muscorum an active proline oxidase enzyme is required to assimilate exogenous proline as a fixed nitrogen source. cyanobacterial mutants, resistant to growth inhibitory action of proline analogue l-azetidine-2-carboxylate (ac-r), were deficient in proline oxidase activity, and were over-accumulators of proline. proline over-accumulation, resulting either from mutational acquisition of the ac-r phenotype, or from salinity-induced uptake of exogenous proline, confirmed enhance ... | 2006 | 16809859 |
| identification of nostoc punctiforme akinete-expressed genes using differential display. | akinetes are spore-like resting cells formed by certain filamentous cyanobacteria that have increased resistance to environmental stress. they can be found at low frequencies in dense cultures experiencing low light or phosphate limitation, but also form at high frequencies in a zwf mutant strain of nostoc punctiforme following dark incubation in the presence of fructose. the wild-type strain is capable of facultative heterotrophic growth under these conditions and does not form akinetes. to ide ... | 2006 | 16780565 |
| process optimization for poly-beta-hydroxybutyrate production in a nitrogen fixing cyanobacterium, nostoc muscorum using response surface methodology. | a five-level-four-factor central composite rotary design was employed to find out the interactive effects of four variables, viz. concentrations of acetate, glucose and k2hpo4, and dark incubation period on poly-beta-hydroxybutyrate (phb) production in a n2-fixing cyanobacterium, nostoc muscorum. acetate, glucose and dark incubation period exhibited positive impacts on phb yield. using response surface methodology (rsm), a second order polynomial equation was obtained by multiple regression anal ... | 2007 | 16765593 |
| the involvement of the antioxidant system in protection of desert cyanobacterium nostoc sp. against uv-b radiation and the effects of exogenous antioxidants. | in this study, we found that uv-b radiation decreased photosynthetic activity and boosted lipid peroxidation of desert nostoc sp., and exogenous chemicals (ascorbate acid (asc), n-acetylcysteine (nac), and sodium nitroprusside (snp)) had obvious protective effects on photosynthesis and membranes under uv-b radiation. high-concentration snp boosted the activities of antioxidant enzymes, but low-concentration snp reduced the activities of antioxidant enzymes. both nac and asc treatments of cells d ... | 2008 | 16759702 |
| retinal is formed from apo-carotenoids in nostoc sp. pcc7120: in vitro characterization of an apo-carotenoid oxygenase. | the sensory rhodopsin from anabaena (nostoc) sp. pcc7120 is the first cyanobacterial retinylidene protein identified. here, we report on nosaco (nostoc apo-carotenoid oxygenase), encoded by the orf (open reading frame) all4284, as the candidate responsible for the formation of the required chromophore, retinal. in contrast with the enzymes from animals, nosaco converts beta-apo-carotenals instead of beta-carotene into retinal in vitro. the identity of the enzymatic products was proven by hplc an ... | 2006 | 16759173 |
| heavy metal sorption by released polysaccharides and whole cultures of two exopolysaccharide-producing cyanobacteria. | the metal removal capacity of cultures of two capsulated, exopolysaccharide-producing cyanobacteria, cyanospira capsulata and nostoc pcc7936, were tested using copper (ii) as the model metal. c. capsulata cultures removed the greatest amount of copper, with a maximum per unit of biomass (q(max)) of 115.0+/-5.1 mg copper g(-1) of protein, compared with 85.0+/-3.2 removed with nostoc pcc7936 cultures. water solutions of pure polysaccharides (rpss) released into the culture medium by c. capsulata a ... | 2007 | 16758273 |
| nitric oxide binding to prokaryotic homologs of the soluble guanylate cyclase beta1 h-nox domain. | the heme cofactor in soluble guanylate cyclase (sgc) is a selective receptor for no, an important signaling molecule in eukaryotes. the sgc heme domain has been localized to the n-terminal 194 amino acids of the beta1 subunit of sgc and is a member of a family of conserved hemoproteins, called the h-nox family (heme-nitric oxide and/or oxygen-binding domain). three new members of this family have now been cloned and characterized, two proteins from legionella pneumophila (l1 h-nox and l2 h-nox) ... | 2006 | 16728401 |
| screening and selection of most potent diazotrophic cyanobacterial isolate exhibiting natural tolerance to rice field herbicides for exploitation as biofertilizer. | periodic applications of heavy dosages of herbicides in modern rice-agriculture are a necessary evil for obtaining high crop productivity. such herbicides are not only detrimental to weeds but biofertilizer strains of diazotrophic cyanobacteria also. it is therefore, essential to screen and select such biofertilizer strains of diazotrophic cyanobacteria exhibiting natural tolerance to common rice-field herbicides that can be further improved by mutational techniques to make biofertilizer technol ... | 2006 | 16721882 |
| mutagenic definition of a papain-like catalytic triad, sufficiency of the n-terminal domain for single-site core catalytic enzyme acylation, and c-terminal domain for augmentative metal activation of a eukaryotic phytochelatin synthase. | phytochelatin (pc) synthases are gamma-glutamylcysteine (gamma-glu-cys) dipeptidyl transpeptidases that catalyze the synthesis of heavy metal-binding pcs, (gamma-glu-cys)ngly polymers, from glutathione (gsh) and/or shorter chain pcs. here it is shown through investigations of the enzyme from arabidopsis (arabidopsis thaliana; atpcs1) that, although the n-terminal half of the protein, alone, is sufficient for core catalysis through the formation of a single-site enzyme acyl intermediate, it is no ... | 2006 | 16714405 |
| regulated expression of glutamyl-trna synthetase is directed by a mobile genetic element in the cyanobacterium tolypothrix sp. pcc 7601. | the genome of tolypothrix sp. pcc 7601 carries two copies of a novel insertion sequence, istosp1. one of the two copies is located upstream of the gene encoding glutamyl-trna synthetase, an enzyme playing a key role in protein and pigment synthesis. the tnpa gene of the is element and gltx were co-transcribed and their expression was transiently upregulated upon retrieval of the ammonium source irrespective of whether nitrate or no nitrogen source were available. the second copy is also transcri ... | 2006 | 16689802 |
| a novel delta9 acyl-lipid desaturase, desc2, from cyanobacteria acts on fatty acids esterified to the sn-2 position of glycerolipids. | acyl-lipid desaturases are enzymes that convert a c-c single bond into a c=c double bond in fatty acids that are esterified to membrane-bound glycerolipids. four types of acyl-lipid desaturase, namely desa, desb, desc, and desd, acting at the delta12, delta15, delta9, and delta6 positions of fatty acids respectively, have been characterized in cyanobacteria. these enzymes are specific for fatty acids bound to the sn-1 position of glycerolipids. in the present study, we have cloned two putative g ... | 2006 | 16689682 |
| n(2)-fixation by freshly isolated nostoc from coralloid roots of the cycad macrozamia riedlei (fisch. ex gaud.) gardn. | nitrogenase (ec 1.7.99.2) activity (acetylene reduction) and nitrogen fixation ((15)n(2) fixation) were measured in cyanobacteria freshly isolated from the coralloid roots of macrozamia riedlei (fisch. ex gaud.) gardn. light and gas phase oxygen concentration had marked interactive effects on activity, with higher (up to 100-fold) rates of acetylene reduction and (15)n(2) fixation in light. the relationship between ethylene formation and n(2)-fixation varied in the freshly isolated cyanobacteria ... | 1991 | 16668050 |
| boron requirement in cyanobacteria : its possible role in the early evolution of photosynthetic organisms. | the effect of boron on heterocystous and nonheterocystous dinitrogen fixing cyanobacteria was examined. the absence of boron in culture media inhibited growth and nitrogenase activity in nodularia sp., chlorogloeopsis sp., and nostoc sp. cultures. examinations of boron-deficient cultures showed changes in heterocyst morphology. however, cultures of nonheterocystous cyanobacteria, gloeothece sp. and plectonema sp., grown in the absence of boron did not show any alteration in growth or nitrogenase ... | 1990 | 16667889 |
| occurrence and localization of phycoerythrin in symbiotic nostoc of cycas revoluta and in the free-living isolated nostoc 7422. | the phycobiliprotein phycoerythrin was localized in symbiotic and free-living nostoc of the cycad cycas using immunocytochemistry. in symbiotic nostoc, phycoerythrin was associated with the thylakoid membranes of vegetative cells and absent from heterocysts. similar cellular/subcellular localization was observed between symbiotic nostoc and the free-living cycas isolate nostoc 7422. | 1989 | 16666621 |
| a new uv-a/b protecting pigment in the terrestrial cyanobacterium nostoc commune. | a new ultraviolet (uv)-a/b absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium nostoc commune is described. the pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar uv radiation but only in low concentrations in laboratory cultures illuminated by artificial light without uv. its experimental induction by uv as well as its capacity to efficiently protect nostoc against uv radiation is reported. | 1988 | 16666420 |
| n-terminus conservation in the terminal pigment of phycobilisomes from a prokaryotic and eukaryotic alga. | high molecular weight polypeptides from phycobilisomes, believed to be involved in facilitating the energy flow from phycobilisomes to thylakoids, are conserved in the prokaryote nostoc sp. and the eukaryote porphyridium cruentum. partial n-terminal sequence analysis of the phycobilisome-polypeptides of nostoc (94 kilodalton) and porphyridium (92 kilodalton) revealed 55% identity in the first 20 residues, but no significant homology with sequences of other phycobiliproteins or phycobilisome-link ... | 1988 | 16666079 |
| sodium requirement for photosynthesis and its relationship with dinitrogen fixation and the external co(2) concentration in cyanobacteria. | cells of anabaena pcc 7119 and of a mutant strain of nostoc muscorum unable to fix dinitrogen, grown at ph 8 and under low co(2) tension (air), showed a reduced capacity for photosynthesis when cultured in the absence of sodium, this inhibition being followed by symptoms of photooxidation, such as chlorosis, oxygen consumption in the light, and decrease of superoxide dismutase activity. the impairment of photosynthesis preceded that of nitrogenase activity, indicating that the requirement for so ... | 1987 | 16665740 |
| immunological conservation of phycobilisome rod linker polypeptides. | monospecific polyclonal antibodies raised against the phycobilisome rod linker polypeptides of nostoc sp. were used to assess structural similarities among phycobilisome linker proteins from diverse, phycobilisome-containing organisms. while a remarkable conservation of antigenic determinants was demonstrated for two of these rod linker proteins, the third linker polypeptide appeared to be conserved only among closely related species. | 1987 | 16665695 |
| the immunologically conserved phycobilisome-thylakoid linker polypeptide. | we have isolated phycobilisomes from two classes of red algae, several subdivisions of the cyanobacteria, and the cyanelles of cyanophora paradoxa. in addition to the major light harvesting biliproteins, these phycobilisomes also contain several other polypeptides, the largest of which ranges from 75 to 120 kilodaltons in the different species surveyed. this protein, previously isolated and characterized from three species, was shown to be the final emitter of excitation energy in phycobilisomes ... | 1986 | 16664726 |
| constant phycobilisome size in chromatically adapted cells of the cyanobacterium tolypothrix tenuis, and variation in nostoc sp. | phycobilisomes of tolypothrix tenuis, a cyanobacterium capable of complete chromatic adaptation, were studied from cells grown in red and green light, and in darkness. the phycobilisome size remained constant irrespective of the light quality. the hemidiscoidal phycobilisomes had an average diameter of about 52 nanometers and height of about 33 nanometers, by negative staining. the thickness was equivalent to a phycocyanin molecule (about 10 nanometers). the molar ratio of allophycocyanin, relat ... | 1985 | 16664550 |
| role of the colorless polypeptides in phycobilisome assembly in nostoc sp. | we have identified the function of the ;extra' polypeptides involved in phycobilisome assembly in nostoc sp. these phycobilisomes, as those of other cyanobacteria, are composed of an allophycocyanin core, phycoerythrin- and phycocyanin-containing rods, and five additional polypeptides of 95, 34.5, 34, 32, and 29 kilodaltons. the 95 kilodalton polypeptide anchors the phycobilisome to the thylakoid membrane (rusckowski, zilinskas 1982 plant physiol 70: 1055-1059); the 29 kilodalton polypeptide att ... | 1983 | 16662834 |
| growth and chromatic adaptation of nostoc sp. strain mac and the pigment mutant r-mac. | a spontaneous, stable, pigmentation mutant of nostoc sp. strain mac was isolated. under various growth conditions, this mutant, r-mac, had similar phycoerythrin contents (relative to allophycocyanin) but significantly lower phycocyanin contents (relative to allophycocyanin) than the parent strain. in saturating white light, the mutant grew more slowly than the parent strain. in nonsaturating red light, mac grew with a shorter generation time than the mutant; however, r-mac grew more quickly in n ... | 1982 | 16662715 |
| isolation and characterization of the central component of the phycobilisome core of nostoc sp. | freshly isolated allophycocyanin is recovered from linear sucrose gradients made in 0.75 molar potassium phosphate buffer (ph 7.0) in three sizes: 19s, 10.3s, and 5.5s. the largest aggregate is a complex of a 680 nm fluorescing allophycocyanin i in the form (alphabeta)(3)gamma, where gamma is the 95 kilodalton (kd) polypeptide, and two 660 nanometer fluorescing allophycocyanin ii (alphabeta)(3) molecules; the complex, stabilized in high phosphate concentrations, fluoresces maximally at 675 nanom ... | 1982 | 16662613 |
| allophycocyanin i and the 95 kilodalton polypeptide : the bridge between phycobilisomes and membranes. | allophycocyanin was isolated from dissociated phycobilisomes from nostoc sp. and was separated into allophycocyanin i, ii, iii, and b as described elsewhere. if the separation of the proteins following phycobilisome isolation is done in the presence of the protease inhibitor, phenylmethylsulfonylfluoride, associated with allophycocyanin i are two colored polypeptides of 95 kilodalton (kd) and 80 kd, belonging to the class of group i polypeptides as defined by tandeau de marsac and cohen-bazire ( ... | 1982 | 16662612 |
| role of the colorless polypeptides in phycobilisome reconstitution from separated phycobiliproteins. | a phycoerythrin (pe) and phycocyanin (pc) mixture was separated from allophycocyanin on calcium phosphate chromatography from completely dissociated phycobilisomes of the blue-green alga, nostoc sp. after dialysis of the pe-pc mixture in 0.75 m potassium phosphate, ph 7, which allows reassociation of the dissociated pigment-proteins, complexes of pe and pc in a 2:1 m ratio (pe/pc complex) as well as complexes predominantly of pc (pc/pe complex) were then separated by sedimentation on linear sucr ... | 1982 | 16662378 |
| oxidation of c-type cytochromes by the membrane-bound cytochrome oxidase (cytochrome aa(3)) of blue-green algae. | respiratory particles containing an aa(3)-type cytochrome oxidase were prepared from anacystis nidulans, synechocystis 6714, synechococcus lividus, anabaena variabilis, nostoc sp. strain mac, nostoc muscorum, and mastigocladus laminosus. oxidation of c-type cytochromes by membrane preparations of the different blue-green algae was observed using purified cytochromes from horse heart, candida krusei, tuna, saccharomyces oviformis, rhodospirillum rubrum, rhodospirillum molischianum, rhodopseudomon ... | 1982 | 16662253 |
| light and dark reactions of the uptake hydrogenase in anabaena 7120. | reactions of the uptake hydrogenase from anabaena 7120 (a.t.c.c. 27893, nostoc muscorum) were examined in whole filaments, isolated heterocysts, and membrane particles. whole filaments or isolated heterocysts that contained nitrogenase consumed h(2) in the presence of c(2)h(2) or n(2) in a light-dependent reaction. if nitrogenase was inactivated by o(2) shock, filaments catalyzed h(2) uptake to an unidentified endogenous acceptor in the light. addition of no(3) (-) or no(2) (-) enhanced these ra ... | 1981 | 16661985 |
| photophosphorylation capacity of stable spheroplast preparations of anabaena. | spheroplasts from anabaena 7119 (formerly designated nostoc muscorum) were prepared in the presence of serum albumin in 0.5 molar sucrose. electron transport and photophosphorylation were preserved (> 70% of the maximum rate for 1 week). the ph profile of electron transport and photophosphorylation in the reactions h(2)o --> nadp, h(2)o --> methyl viologen, and h(2)o --> ferricyanide shows that uncoupling by ammonia is small throughout and increases slightly with higher ph. adp + pi increased na ... | 1980 | 16661453 |
| chlorophyll-protein complexes of the cyanophyte, nostoc sp. | four chlorophyll-protein complexes have been resolved from the cyanophyte, nostoc sp., by sodium dodecyl sulfate (sds) polyacrylamide gel electrophoresis at 4 c. complexes solubilized by sds from spinacia oleracea were run for comparison. as has been well documented, the p700-chlorophyll a-protein complex from the higher plant and blue-green algal samples are similar, and the light-harvesting pigment protein complex is present only in the former. most noteworthy are two closely migrating chlorop ... | 1980 | 16661198 |
| light-induced changes in allophycocyanin. | several lines of evidence indicate that allophycocyanin is the previously unidentified "phycochrome" observed in extracts of blue-green algae.fractions containing phycoerythrin, phycocyanin, and allophycocyanin and exhibiting light-induced absorbance changes were prepared from extracts of nostoc muscorum and fremyella diplosiphon by isoelectric focusing. illumination of such fractions with red light (650 nanometers) causes a reduction in absorbance at 620 nm ( approximately 1 to 2%) and an incre ... | 1980 | 16661143 |
| phycobilisomes from blue-green and red algae: isolation criteria and dissociation characteristics. | a general procedure for the isolation of functionally intact phycobilisomes was devised, based on modifications of previously used procedures. it has been successful with numerous species of red and blue-green algae (anabaena variabilis, anacystis nidulans, agmenellum quadruplicatum, fremyella diplosiphon, glaucosphaera vacuolata, griffithsia pacifica, nemalion multifidum, nostoc sp., phormidium persicinum, porphyridium cruentum, p. sordidum, p. aerugineum, rhodosorus marinus). isolation was car ... | 1979 | 16660778 |
| purification and characterization of glucose dehydrogenase from a heterotrophically grown blue-green alga. | nadp- and nad-dependent glucose dehydrogenase was partially purified from a dark-grown blue-green alga (endophytic nostoc strain mac). polyacrylamide gel electrophoresis established that a single protein possessed dual activity for either nadp or nad. no other electron acceptor substituted for pyridine nucleotides and no evidence for a flavin prosthetic group was found. although the km for nadp was 8.8 mum and for nad 328 mum, the enzyme was equally active with nad or nadp at saturating levels o ... | 1976 | 16659685 |
| partial purification and properties of ornithine transcarbamoylase from nostoc muscorum kützing. | ornithine transcarbamoylase (carbamoyl phosphate:l-ornithine carbamoyltransferase, ec 2.1.3.3) has been partially purified from the blue-green alga nostoc muscorum kützing, an organism in which the enzyme seems to be involved in a bicarbonate-fixing pathway leading to citrulline. pertinent to possible regulation of this pathway, the enzyme shows hyperbolic substrate kinetics, has a molecular weight estimated at 75,000 daltons, and its catalytic capability is little influenced by a selection of m ... | 1975 | 16659361 |
| studies on the photosynthetic reaction. ii. sodium formate and urea feeding experiments with nostoc muscorum. | 1954 | 16654631 | |
| molecular mechanisms in the nitrogen-fixing nostoc-bryophyte symbiosis. | 2006 | 16623394 | |
| ftsz may have dual roles in the filamentous cyanobacterium nostoc/anabaena sp. strain pcc 7120. | the cellular and subcellular localization of ftsz, a bacterial cell division protein, were investigated in vegetative cells of the filamentous cyanobacterium nostoc/anabaena sp. strain pcc 7120. we show by using immunogold-transmission electron microscopy that ftsz forms a ring structure in a filamentous cyanobacterium, similar to observations in unicellular bacteria and chloroplasts. this finding, that the ftsz in a filamentous cyanobacterium accumulates at the growing edge of the division sept ... | 2007 | 16603273 |
| studies of osmoregulation in salt adaptation of cyanobacteria with esr spin-probe techniques. | sucrose is accumulated in response to nacl-induced stress in the cyanobacterium synechococcus 6311. internal cell volume was measured by esr spectra with 2,2,6,6-tetramethyl-4-oxopiperidinoxy free radical (tempone) as a spin probe in order to calculate sucrose concentrations inside the cell. this method is rapid and reliable and provides an unambiguous measurement of absolute volumes in different osmotic environments. because the osmolar concentration of sucrose does not counter-balance the osmo ... | 1983 | 16593309 |
| formation of hybrid phycobilisomes by association of phycobiliproteins from nostoc and fremyella. | formation of phycobilisomes has been accomplished in vitro from isolated phycobiliprotein fractions obtained from the same blue-green alga (intrageneric) and from different blue-green algae (intergeneric). phycobilisomes, which are supra-molecular complexes of phycobiliproteins, serve as major light-harvesting antennae for photosynthesis in blue-green and red algae. intrageneric association into energetically functional phycobilisomes, previously reported to occur with nostoc sp. allophycocyanin ... | 1982 | 16593223 |
| nucleotide sequence of a multiple-copy gene for the b protein of photosystem ii of a cyanobacterium. | chloroplast photogene 32 codes for the 32-kilodalton triazine herbicide-binding protein at the b site of electron transport in photosystem ii of the photosynthetic apparatus-its product is the b protein and the gene is accordingly designated ps2b here. the cyanobacteria anacystis nidulans r2, fremyella diplosiphon, and nostoc sp. mac each contain several copies of ps2b. the sequence of one copy of ps2b from fremyella, ps2b-1, has been determined. the longest open reading frame would code for a p ... | 1984 | 16578775 |
| commercial applications of microalgae. | the first use of microalgae by humans dates back 2000 years to the chinese, who used nostoc to survive during famine. however, microalgal biotechnology only really began to develop in the middle of the last century. nowadays, there are numerous commercial applications of microalgae. for example, (i) microalgae can be used to enhance the nutritional value of food and animal feed owing to their chemical composition, (ii) they play a crucial role in aquaculture and (iii) they can be incorporated in ... | 2006 | 16569602 |
| diversity of the fatty acids of the nostoc species and their statistical analysis. | low molecular, hydroxy, dioic, saturated and unsaturated fatty acids were determined of six cyanobacterial species belonging to genus nostoc and in different habitats: freshwater, terrestrial, and as well as symbionts. there are large variations in individual fatty acid contents according to species, and location of the genus nostoc. statistical analysis of variability of fatty acids belonging to the genus nostoc is reported. | 2007 | 16563711 |
| molecular cloning and functional characterization of a cell-permeable superoxide dismutase targeted to lung adenocarcinoma cells. inhibition cell proliferation through the akt/p27kip1 pathway. | in clinical oncology, many trials with superoxide dismutase (sod) have failed to demonstrate antitumor ability and in many cases even caused deleterious effects because of low tumor-targeting ability. in the current research, the nostoc commune fe-sod coding sequence was amplified from genomic dna. in addition, the single chain variable fragment (scfv) was constructed from the cdna of an lc-1 hybridoma cell line secreting anti-lung adenocarcinoma monoclonal antibody. after modification, the sod ... | 2006 | 16551617 |
| cyanobacterial response regulator pata contains a conserved n-terminal domain (patan) with an alpha-helical insertion. | the cyanobacterium anabaena (nostoc) pcc 7120 responds to starvation for nitrogen compounds by differentiating approximately every 10th cell in the filament into nitrogen-fixing cells called heterocysts. heterocyst formation is subject to complex regulation, which involves an unusual response regulator pata that contains a chey-like phosphoacceptor (receiver, rec) domain at its c-terminus. pata-like response regulators are widespread in cyanobacteria; one of them regulates phototaxis in synechoc ... | 2006 | 16543275 |
| poly-beta-hydroxybutyrate accumulation in nostoc muscorum: effects of metabolic inhibitors. | poly-beta-hydroxybutyrate (phb) accumulation in nostoc muscorum was studied in presence of various metabolic inhibitors. supplementation of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu) was found to suppress phb accumulation in phosphate-limited n. muscorum under photoautotrophic growth condition. phb accumulation increased up to 21% and 17% from an initial phb content of 8.5% of dry weight, respectively, under carbonylcyanide m-chlorophenylhydrazone (cccp) and dicyclohexylcarbodiimide (dccd) t ... | 2007 | 16542751 |
| 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 |
| 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 |
| highly efficient protein trans-splicing by a naturally split dnae intein from nostoc punctiforme. | protein trans-splicing by the naturally split intein of the gene dnae from nostoc punctiforme (npu dnae) was demonstrated here with non-native exteins in escherichia coli. npu dnae possesses robust trans-splicing activity with an efficiency of > 98%, which is superior to that of the dnae intein from synechocystis sp. strain pcc6803 (ssp dnae). both the n- and c-terminal parts of the split npu dnae intein can be substituted with the corresponding fragment of ssp dnae without loss of trans-splicin ... | 2006 | 16516207 |
| crystallization and preliminary x-ray crystallographic analysis of the glur0 ligand-binding core from nostoc punctiforme. | glur0 from nostoc punctiforme (npglur0) is a bacterial homologue of the ionotropic glutamate receptor. the ligand-binding core of npglur0 was crystallized at 294 k using the hanging-drop vapour-diffusion method. the l-glutamate-complexed crystal belongs to space group c222(1), with unit-cell parameters a = 78.0, b = 145.1, c = 132.1 a. the crystals contain three subunits in the asymmetric unit, with a vm value of 2.49 a3 da(-1). the diffraction limit of the l-glutamate complex data set was 2.1 a ... | 2005 | 16511224 |
| metabolites produced by nitrogen-fixing nostoc species. | this paper provides a comprehensive overview of metabolites, including lipids and lipid-like compounds, boron-containing macrocycles, arsenolipids, oligopeptides and amino acid derivatives, produced by cyanobacteria of the genus nostoc. | 2005 | 16475497 |
| cyanobacterial chemotaxis to extracts of host and nonhost plants. | chemotaxis may be important when forming cyanobacterial symbioses. however, knowledge of cyanobacterial attraction towards plants and factors affecting chemotaxis is limited. chemo-attraction was observed in nostoc strains 8964:3 and pcc 73102 towards exudate or crushed extract of the natural hosts gunnera manicata, cycas revoluta and blasia pusilla, and the nonhost plants trifolium repens, arabidopsis thaliana and oryza sativa. as all tested plant extracts generated chemotaxis, the possibility ... | 2006 | 16466377 |
| high-light-induced changes on photosynthesis, pigments, sugars, lipids and antioxidant enzymes in freshwater (nostoc spongiaeforme) and marine (phormidium corium) cyanobacteria. | we studied the effects of high-light exposure (500 micromol m(-2) s(-1) of photosynthetic active radiation) on the cyanobacteria nostoc spongiaeforme agardh, a fresh-water alga, and phormidium corium agardh (gomont), a marine alga, with respect to photosynthesis, pigments, sugar content, lipid peroxidation, fatty acids composition, antioxidant enzymes activity and dna. it was seen that the ratio of variable fluorescence (fv) to maximum fluorescence (fm), which is indicative of photosynthetic eff ... | 2006 | 16464127 |
| poly-beta-hydroxybutyrate accumulation in nostoc muscorum and spirulina platensis under phosphate limitation. | nostoc muscorum and spirulina platensis were grown under phosphate deficiency in order to investigate the role of internal phosphate pool and activity of alkaline phosphatase on poly-beta-hydroxybutyrate (phb) accumulation. phb accumulation in n. muscorum increased to 22.7% of dry weight (dw) after 4 day of phosphate deficiency, while the internal phosphate pool reduced to the level of 0.02 microm mg dw(-1) at a maximum apase activity of 2.57nm pnp mg dw(-1) h(-1). in contrary, s. platensis depi ... | 2005 | 16425456 |
| a mannan binding lectin is involved in cell-cell attachment in a toxic strain of microcystis aeruginosa. | microcystin, a hepatotoxin that represents a serious health risk for humans and livestock, is produced by the bloom-forming cyanobacterium microcystis aeruginosa in freshwater bodies worldwide. here we describe the discovery of a lectin, microvirin (mvn), in m. aeruginosa pcc7806 that shares 33% identity with the potent anti-hiv protein cyanovirin-n from nostoc ellipsosporum. carbohydrate microarrays were employed to demonstrate the high specificity of the protein for high-mannose structures con ... | 2006 | 16420359 |
| phytochelatin synthase, papain's cousin, in stereo. | 2006 | 16407124 | |
| nostocarboline: isolation and synthesis of a new cholinesterase inhibitor from nostoc 78-12a. | a new quaternary beta-carboline alkaloid, nostocarboline, was isolated from the freshwater cyanobacterium nostoc 78-12a, and its constitution was assigned by 2d-nmr methods. the structure was proven by its total synthesis starting from norharmane via chlorination at c-6 and methylation at n-2. nostocarboline was found to be a potent butyrylcholinesterase (bche) inhibitor, with an ic(50) of 13.2 microm. the related 2-methylnorharmane, which is present in the human brain and might be relevant to p ... | 2005 | 16378379 |
| occurrence of glucosylsucrose [alpha-d-glucopyranosyl- (1-->2)-alpha-d-glucopyranosyl-(1-->2)-beta-d-fructofuranoside] and glucosylated homologues in cyanobacteria. structural properties, cellular contents and possible function as thermoprotectants. | little is known about the structure and function of oligosaccharides in cyanobacteria. in this study, a new class of saccharides from nostoc was identified by ms and nmr techniques, consisting of alpha-d-glucopyranosyl-(1-->2)-[alpha-d-glucopyranosyl-(1-->2)]n-beta-d-fructofuranosides ranging from the trisaccharide (n = 1) to decasaccharide (n = 8). in nostoc ellipsosporum the cell content of saccharides increased 10-20-fold after heat stress (1 day, 40 degrees c) or during prolonged cultivation ... | 2006 | 16367754 |
| 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 |
| methods involving light variation for isolation of cyanobacteria: characterization of isolates from central australia. | we report the isolation of organisms belonging to a range of cyanobacterial genera from the remote arid region of central australia, together with a preliminary characterization of their temporal modes of nitrogen fixation. we rendered unialgal dermocarpa and myxosarcina spp. (section ii organisms), lpp group b: type x (section iii), and scytonema and nostoc spp. (section iv). we developed an isolation procedure based on a combination of published methods and applicable to a broad spectrum of cy ... | 1992 | 16348803 |
| dna probes show genetic variation in cyanobacterial symbionts of the azolla fern and a closer relationship to free-living nostoc strains than to free-living anabaena strains. | twenty-two isolates of anabaena azollae derived from seven azolla species from various geographic and ecological sources were characterized by dna-dna hybridization. cloned dna fragments derived from the genomic sequences of three different a. azollae isolates were used to detect restriction fragment length polymorphism among all symbiotic anabaenas. dna clones were radiolabeled and hybridized against southern blot transfers of genomic dnas of different isolates of a. azollae digested with restr ... | 1990 | 16348182 |
| microscale vertical profiles of n(2) fixation, photosynthesis, o(2), chlorophyll a, and light in a cyanobacterial assemblage. | profiles of n(2) fixation, o(2) production (gross photosynthesis), o(2) concentration, chlorophyll a concentration, and photon fluence rates were measured with 50-mum resolution in colonies of the heterocyst-forming cyanobacterium nostoc parmelioides. microelectrode measurements were made after 20 h of incubation under n(2) gas. colonies were frozen, and 50-mum sections were prepared by using a freezing microtome and analyzed for n enrichment and chlorophyll a concentration. colonies exhibited s ... | 1989 | 16347893 |
| characteristics of hormogonia formation by symbiotic nostoc spp. in response to the presence of anthoceros punctatus or its extracellular products. | nostocacean cyanobacteria typically produce gliding filaments termed hormogonia at a low frequency as part of their life cycle. we report here that all nostoc spp. competent in establishing a symbiotic association with the hornwort anthoceros punctatus formed hormogonial filaments at a high frequency in the presence of a. punctatus. the hormogonia-inducing activity was produced by a. punctatus under nitrogen-limited culture conditions. the hormogonia of the symbiotically competent nostoc spp. we ... | 1989 | 16347816 |
| variation in phospholipid ester-linked fatty acids and carotenoids of desiccated nostoc commune (cyanobacteria) from different geographic locations. | profiles of phospholipid fatty acids and carotenoids in desiccated nostoc commune (cyanobacteria) collected from china, federal republic of germany, and antarctica and in axenic cultures of the desiccation-tolerant strains n. commune utex 584 and hydrocoleum strain goei were analyzed. the phospholipid fatty acid contents of the three samples of desiccated nostoc species were all similar, and the dominant compounds were 16:1omega7c, 16:0, 18:2omega6, 18:3omega3, and 18:1omega7c. in comparison wit ... | 1987 | 16347265 |
| purification and biochemical analysis of the cytoplasmic membrane from the desiccation-tolerant cyanobacterium nostoc commune utex 584. | the cytoplasmic membrane of the heterocystous cyanobacterium nostoc commune utex 584 was isolated free of thylakoids and phycobiliprotein-membrane complexes by flotation centrifugation. purified membranes had a buoyant density of 1.07 g cm and were bright orange. twelve major proteins were detected in the membrane, and of these, the most abundant had molecular masses of 83, 71, 68, 51, and 46 kilodaltons. the ester-linked fatty acids of the methanol fraction contained 16:0, 18:0, 18:1omega9c, 20 ... | 1986 | 16347165 |
| freeze-recovery physiology of nitrogenase activity in terrestrial nostoc sp. colonies. | nostoc sp. colonies from field collections were cultured and propagated on silica sand with aqueous n-free bg-11 medium. laboratory experiments were conducted to characterize the in vivo freeze-recovery physiology of nitrogenase activity. nitrogenase activity was monitored by the acetylene reduction technique. frozen nostoc sp. colonies were thawed and warmed to 10, 15, 20, 25, or 30 degrees c. at 25 and 30 degrees c, nitrogenase activity was detected within 6 h after thawing. at 20 degrees c or ... | 1983 | 16346394 |
| response of n(2)-fixing cyanobacteria to salt. | the effect of salt on photosynthetic activity, acetylene reduction, and related activities was examined in two species of cyanobacteria, nostoc muscorum and calothrix scopulorum. photosynthesis was more resistant to high salt concentration than was n(2) fixation. the salt resistance of both activities increased after a period of exposure of the cells to salinity. the transfer of electrons via ferredoxin and ferredoxin-nicotinamide adenine dinucleotide phosphate reductase was found to be extremel ... | 1980 | 16345644 |
| transcription and autoregulation of the rv3134c-devr-devs operon of mycobacterium tuberculosis. | devr is a transcriptional regulator that mediates the genetic response of mycobacterium tuberculosis to oxygen limitation and nitric oxide exposure. devr is co-transcribed along with devs, which encodes its cognate sensor kinase, and an upstream gene, rv3134c. the transcriptional activity of this operon was characterized by primer extension, transcriptional fusion and electrophoretic mobility shift assays (emsas) under aerobic conditions. transcription start points (tsps) were detected upstream ... | 2005 | 16339949 |
| a papain-like enzyme at work: native and acyl-enzyme intermediate structures in phytochelatin synthesis. | phytochelatin synthase (pcs) is a key enzyme for heavy-metal detoxification in plants. pcs catalyzes the production of glutathione (gsh)-derived peptides (called phytochelatins or pcs) that bind heavy-metal ions before vacuolar sequestration. the enzyme can also hydrolyze gsh and gs-conjugated xenobiotics. in the cyanobacterium nostoc, the enzyme (nspcs) contains only the catalytic domain of the eukaryotic synthase and can act as a gsh hydrolase and weakly as a peptide ligase. the crystal struct ... | 2005 | 16339904 |
| a conserved histidine-aspartate pair is required for exovinyl reduction of biliverdin by a cyanobacterial phycocyanobilin:ferredoxin oxidoreductase. | phycocyanobilin:ferredoxin oxidoreductase is a member of the ferredoxin-dependent bilin reductase family and catalyzes two vinyl reductions of biliverdin ixalpha to produce phycocyanobilin, the pigment precursor of both phytochrome and phycobiliprotein chromophores in cyanobacteria. atypically for ferredoxin-dependent enzymes, phycocyanobilin:ferredoxin oxidoreductase mediates direct electron transfers from reduced ferredoxin to its tetrapyrrole substrate without metal ion or organic cofactors. ... | 2006 | 16327013 |
| acclimation of chlorophyll a and carotenoid levels to different irradiances in four freshwater cyanobacteria. | this study investigated carotenoid and chlorophyll a (chl-a) contents under two different growth irradiances in four freshwater cyanobacterial strains. we found an increased weight ratio of zeaxanthin to chl-a after exposure to high irradiances over several days. two out of four strains showed higher zeaxanthin amounts on a biomass basis as well. it appears that cyanobacteria enhance their carotenoid pool in response to high light conditions, as increased production of other carotenoids with pho ... | 2006 | 16325961 |
| a study on the correlation of nucleotide skews and the positioning of the origin of replication: different modes of replication in bacterial species. | deviations from chargaff's 2nd parity rule, according to which a approximately t and g approximately c in single stranded dna, have been associated with replication as well as with transcription in prokaryotes. based on observations regarding mainly the transcription-replication co-linearity in a large number of prokaryotic species, we formulate the hypothesis that the replication procedure may follow different modes between genomes throughout which the skews clearly follow different patterns. w ... | 2005 | 16321966 |
| characterization of nitrogen-fixing cyanobacteria in the brazilian amazon floodplain. | the diversity of the free-living nitrogen-fixing cyanobacterial community in the floodplain sediments along the solimões and amazon rivers and some of their tributaries (japurá, negro and madeira) was investigated. five cyanobacterial genera were morphologically identified, four of which (nostoc, calothrix, cylindrospermum and fischerella) have not previously been isolated from the brazilian amazon floodplain. nostoc strains were the most commonly found heterocyst-forming cyanobacteria. five str ... | 2005 | 16289234 |