| phylogenetic and morphological evaluation of the genera anabaena, aphanizomenon, trichormus and nostoc (nostocales, cyanobacteria). | the heterocytous cyanobacteria form a monophyletic group according to 16s rrna gene sequence data. within this group, phylogenetic and morphological studies have shown that genera such as anabaena and aphanizomenon are intermixed. moreover, the phylogeny of the genus trichormus, which was recently separated from anabaena, has not been investigated. the aim was to study the taxonomy of the genera anabaena, aphanizomenon, nostoc and trichormus belonging to the family nostocaceae (subsection iv.i) ... | 2005 | 15653847 |
| enhancement of poly-beta-hydroxybutyrate accumulation in nostoc muscorum under mixotrophy, chemoheterotrophy and limitations of gas-exchange. | nostoc muscorum, a heterocystous cyanobacterium, produced poly-beta-hydroxybutyrate ( phb) up to 8% (w/w) dry cells when grown photoautotrophically but 35% when grown mixotrophically with 0.4% (w/v) glucose and acetate after 21 d. gas-exchange limitations under mixotrophy and chemoheterotrophy with 0.4% (w/v) acetate enhanced the accumulation up to 40-43% (w/w) dry cells, the value almost 5-fold higher with respect to photoautotrophic condition. | 2005 | 15685421 |
| myxol and 4-ketomyxol 2'-fucosides, not rhamnosides, from anabaena sp. pcc 7120 and nostoc punctiforme pcc 73102, and proposal for the biosynthetic pathway of carotenoids. | we identified the molecular structures of carotenoids in some anabaena and nostoc species. the myxoxanthophyll and ketomyxoxanthophyll in anabaena (also known as nostoc) sp. pcc 7120, anabaena variabilis iam m-3, nostoc punctiforme pcc 73102 and nostoc sp. hk-01 were (3r,2's)-myxol 2'-fucoside and (3s,2's)-4-ketomyxol 2'-fucoside, respectively. the glycoside moiety of the pigments was fucose, not rhamnose. the major carotenoids were beta-carotene and echinenone, and the minor ones were beta-cryp ... | 2005 | 15695449 |
| structure of the complex between plastocyanin and cytochrome f from the cyanobacterium nostoc sp. pcc 7119 as determined by paramagnetic nmr. the balance between electrostatic and hydrophobic interactions within the transient complex determines the relative orientation of the two proteins. | the complex between cytochrome f and plastocyanin from the cyanobacterium nostoc has been characterized by nmr spectroscopy. the binding constant is 16 mm(-1), and the lifetime of the complex is much less than 10 ms. intermolecular pseudo-contact shifts observed for the plastocyanin amide nuclei, caused by the heme iron, as well as the chemical-shift perturbation data were used as the sole experimental restraints to determine the orientation of plastocyanin relative to cytochrome f with a precis ... | 2005 | 15705583 |
| photochromicity of anabaena sensory rhodopsin, an atypical microbial receptor with a cis-retinal light-adapted form. | we characterize changes in isomeric states of the retinylidene chromophore during light-dark adaptation and photochemical reactions of anabaena (nostoc) sp. pcc7120 sensory rhodopsin (asr). the results show that asr represents a new type of microbial rhodopsin with a number of unusual characteristics. the three most striking are: (i) a primarily all-trans configuration of retinal in the dark-adapted state and (ii) a primarily 13-cis light-adapted state with a blue-shifted and lower extinction ab ... | 2005 | 15710603 |
| accumulation of poly-beta-hydroxybutyrate in nostoc muscorum: regulation by ph, light-dark cycles, n and p status and carbon sources. | accumulation of poly-beta-hydroxybutyrate (phb) in nostoc muscorum was studied. cells harvested at stationary phase of growth depicted maximum accumulation i.e. 8.6% (w/w) of dry cells as compared to lag (4.1%) or logarithmic (6.1%) phases of cultures. in contrast to alkaline ph, acidic ph, continuous illumination and cells grown in presence of combined nitrogen sources, such as nh(4)cl and kno(3), were found to affect phb accumulation negatively. however, p-deficiency and addition of exogenous ... | 2004 | 15734319 |
| different modes of interaction in cyanobacterial complexes of plastocyanin and cytochrome f. | the highly efficient electron-transfer chain in photosynthesis demonstrates a remarkable variation among organisms in the type of interactions between the soluble electron-transfer protein plastocyanin and it partner cytochrome f. the complex from the cyanobacterium nostoc sp. pcc 7119 was studied using nuclear magnetic resonance spectroscopy and compared to that of the cyanobacterium phormidium laminosum. in both systems, the main site of interaction on plastocyanin is the hydrophobic patch. ho ... | 2005 | 15736928 |
| conserved pore-forming regions in polypeptide-transporting proteins. | transport of solutes and polypeptides across membranes is an essential process for every cell. in the past, much focus has been placed on helical transporters. recently, the beta-barrel-shaped transporters have also attracted some attention. the members of this family are found in the outer bacterial membrane and the outer membrane of endosymbiotically derived organelles. here we analyze the features and the evolutionary development of a specified translocator family, namely the beta-barrel-shap ... | 2005 | 15752354 |
| a retinoic acid binding cytochrome p450: cyp120a1 from synechocystis sp. pcc 6803. | at least 35 cytochrome p450 (p450, cyp) or cytochrome p450-like genes have been identified in 10 cyanobacterial genomes yet none have been functionally characterized. cyp110 and cyp120 represent the two largest cyanobacterial p450 families with 16 and four members, respectively, identified to date. the synechocystis sp. pcc 6803 cyp120a1 protein sequence shares high degrees of conservation with cyp120a2 from trichodesmium erythraeum ims101 and cyp120b1 and cyp120c1 from nostoc punctiforme pcc 73 ... | 2005 | 15752715 |
| response of growth, photosynthesis and photoinhibition of the edible cyanobacterium nostoc sphaeroides colonies to thiobencarb herbicide. | effects of thiobencarb on growth, photosynthesis and photoinhibition of nostoc sphaeroides colonies were examined. thiobencarb concentrations higher than 2 mg/l led to a significant decrease in phycoerythrin, phycocyanin and allophycocyanin content, but no significant effect on chlorophyll a (chl a) content. biomass yield, protein content and photosynthetic rate were reduced only in the highest thiobencarb concentration (10 mg/l). colonies exposed to high thiobencarb dose (10 mg/l) were more sen ... | 2005 | 15788179 |
| a correlation matrix of alkaline phosphatase and sporulation in diazotrophic cyanobacteria and its thermo-tolerant mutant. | alkaline phosphatase (phosphomonoesterase i.e. pmease) activity in heterocystous cyanobacteria anabaena flos-aquae, nostoc calcicola, calothrix brevissima, scytonema javanicum and hapalosiphon intricatus is known to be temperature and ph dependent. maximum level of enzyme activity was recorded at either 35 degrees c or 37.5 degrees c. also, the cell bound phosphomonoesterase enzyme was shown to exhibit ph optima of 10.0 or 10.2. a thermo-tolerant (tr) mutant isolated after mnng (n-methyl-n'-nitr ... | 2004 | 15790075 |
| real-time studies on microalgae under microgravity. | using remote sensing technique, we investigated real-time nostoc sphaeroides kütz (cyanobacterium) in closed system under microgravity by shenzhou-2 spacecraft in january 2001. the experiments had 1 g centrifuges in space for control and ground control group experiments were also carried out in the same equipments and under the same controlled condition. the data about the population growth of nostoc sp. of experiments and temperature changes of system were got from spacecraft every minute. from ... | 2004 | 15791730 |
| competition among symbiotic cyanobacterial nostoc strains forming artificial associations with rice (oryza sativa). | competition among four symbiotically competent nostoc strains, colonizing rice roots, was examined using hetr-dgge (denaturing gradient gel electrophoresis) as strain identification. although mixed in various combinations, only one strain at a time associated with the rice roots. nostoc strain 8964:3 was the most competitive and our data suggest that its competitive fitness was dependent on rapid hormogonial spreading as displayed on agar plates. furthermore, rice roots induced hormogonia in all ... | 2005 | 15796991 |
| cyanobacteria from brazilian building walls are distant relatives of aquatic genera. | the 16s-rdna from 22 cyanobacteria isolated from biofilms on walls of modern and historic buildings in brazil was partially sequenced (approximately 350 bp) using specific primers. the cyanobacteria with the closest matching sequences were found using the blast tool. the sequences were combined with 52 other cyanobacterial sequences already deposited in public data banks and a dendrogram constructed, after deletion from each sequence of one of the variable 16s rdna regions (vi). the newly sequen ... | 2005 | 15805777 |
| comparative analysis of the two-step reaction catalyzed by prokaryotic and eukaryotic phytochelatin synthase by an ion-pair liquid chromatography assay. | genes encoding phytochelatin (pc) synthase have been found in higher plants, fission yeast and worm. recently, kinetic and mutagenic analyses of recombinant pc synthase have been revealing the molecular mechanisms underlying pc synthesis, however, a conclusive model has not been established. to clarify the mechanism of pc synthase found in eukaryotes, we have compared the two-step reactions catalyzed by the prokaryotic nostoc pc synthase (nspcs) and the eukaryotic arabidopsis pc synthase (atpcs1 ... | 2005 | 15809863 |
| diversity within cyanobacterial mat communities in variable salinity meltwater ponds of mcmurdo ice shelf, antarctica. | this study investigated the diversity of cyanobacterial mat communities of three meltwater ponds--fresh, orange and salt ponds, south of bratina island, mcmurdo ice shelf, antarctica. a combined morphological and genetic approach using clone libraries was used to investigate the influence of salinity on cyanobacterial diversity within these ecosystems without prior cultivation or isolation of cyanobacteria. we were able to identify 22 phylotypes belonging to phormidium sp., oscillatoria sp. and ... | 2005 | 15816929 |
| an nmr-based docking model for the physiological transient complex between cytochrome f and cytochrome c6. | the physiological transient complex between cytochrome f (cf) and cytochrome c(6) (cc(6)) from the cyanobacterium nostoc sp. pcc 7119 has been analysed by nmr spectroscopy. the binding constant at low ionic strength is 8 +/- 2 mm(-1), and the binding site of cc(6) for cf is localized around its exposed haem edge. on the basis of the experimental data, the resulting docking simulations suggest that cc(6) binds to cf in a fashion that is analogous to that of plastocyanin but differs between prokar ... | 2005 | 15876432 |
| characterization of a 4 kb variant of the nifd element in anabaena sp. strain atcc 33047. | heterocyst differentiation in some cyanobacteria is accompanied by a programmed dna rearrangement within the nitrogen fixation gene nifd. the nifd element is excised from within nifd during the latter stages of heterocyst differentiation by site-specific recombination. there is considerable variation in those nifd elements examined thus far, with nostoc sp. strain pcc 7120 and anabaena variabilis having 11 kb elements, and nostoc punctiforme having a 24 kb element. here we characterize a 4 kb ni ... | 2005 | 15883871 |
| benthic cyanobacteria from the baltic sea contain cytotoxic anabaena, nodularia, and nostoc strains and an apoptosis-inducing phormidium strain. | benthic cyanobacteria from aquatic environments have been reported to produce biologically active metabolites. however, the toxicity and other biological activities of benthic cyanobacteria from the baltic sea are not well known. we determined the biological activities of 21 anabaena, calothrix, nodularia, nostoc, and phormidium strains isolated from benthic littoral habitats of the baltic sea. we studied whether benthic cyanobacterial extracts caused cytotoxicity by necrosis or induced apoptosi ... | 2005 | 15892066 |
| the role of potassium as an ionic signal in the regulation of cyanobacterium nostoc muscorum response to salinity and osmotic stress. | spontaneously occurring thallium-resistant (tl+ -r) mutant of diazotrophic, heterocystous cyanobacterium nostoc muscorum is described in which tl+ -r phenotype is the cause of defective salinity-inducible k+ uptake activity and proline uptake activity. the results indicate that mutant strain is more sensitive to salinity and osmotic stresses than its parent. the mutational inactivation of salinity-inducible proline uptake was found associated with increased sensitivity of the cyanobacterial phot ... | 2005 | 15900550 |
| toxic cyanobacteria and microcystin concentrations in a public water supply reservoir in the brazilian amazonia region. | toxic cyanobacteria in public water supply reservoirs represent a serious health risk as they can release potent cyanotoxins into the water. in the present study we analyzed surface water collected from the utinga reservoir, the main source of drinking water for the city of belem-pa, in order to characterize the reservoir's cyanobacterial biota and to determine the toxicity of these organisms and the concentration of microcystins in raw and treated water. the cyanobacterial biota included potent ... | 2005 | 15904685 |
| characterization of a model system for the study of nostoc punctiforme akinetes. | nostoc punctiforme is a filamentous cyanobacterium that is capable of dark heterotrophy and cellular differentiation into nitrogen-fixing heterocysts, motile hormogonia, or spore-like akinetes. the study of akinete differentiation at the molecular level has been limited by the asynchronous development and limited number of akinetes formed within a filament. a system in which to study the development and genetic regulation of akinetes was investigated using a zwf mutant lacking glucose-6-phosphat ... | 2005 | 15905999 |
| raman spectroscopic analysis of cyanobacterial gypsum halotrophs and relevance for sulfate deposits on mars. | the raman spectra of cyanobacterial species, gloecapsa and nostoc, in clear gypsum crystals from the haughton crater, devon island, canadian high arctic, site of a meteorite impact during the miocene some 23 mya, have been recorded using several visible and near-infrared excitation wavelengths. the best spectra were obtained using a green wavelength at 514.5 nm and a confocal microscope with an image footprint of about 2 micro in diameter and 2 micro theoretical depth. raman biosignatures for be ... | 2005 | 15912241 |
| efficient and versatile stereoselective synthesis of cryptophycins. | the cryptophycins are a family of cyclic depsipeptides with four retrosynthetic units a to d which correspond to the respective amino acids and hydroxy acids. a new synthetic route to unit a allows the selective generation of all four stereogenic centres by introducing two of them in a catalytic asymmetric dihydroxylation, followed by substrate-controlled diastereoselective reactions. the diol also serves as the epoxide precursor. this approach provides selective access to stereoisomers of unit ... | 2005 | 15915529 |
| growth of cyanophage n-1 under the influence of heavy metal ions. | the growth of cyanophage n-1 in the cyanobacterium nostoc muscorum under the influence of heavy metal ions, namely co2+, cr6+, cu2+, mn2+ and ni2+ has been studied. one-step growth experiments revealed that heavy metal ions extended the latent period by 1-2 hrs with a concomitant decrease in the phage burst size. the latter was reduced in the order cu2/mn2+, ni2+, co2+ and cr6+. the treatment of the phage-infected bacteria with heavy metal ions did not induce mutations affecting either the phage ... | 2005 | 15929395 |
| the evolutionarily related beta-barrel polypeptide transporters from pisum sativum and nostoc pcc7120 contain two distinct functional domains. | several beta-barrel-type channels are involved in the translocation or assembly of outer membrane proteins of bacteria or endosymbiotically derived organelles. here we analyzed the functional units of the beta-barrel polypeptide transporter toc75 (translocon in outer envelope of chloroplasts) of the outer envelope of chloroplasts and of a protein, alr2269, from nostoc pcc7120 with homology to toc75, both proteins having a similar domain organization. we demonstrated that the n-terminal region fu ... | 2005 | 15951438 |
| three-dimensional architecture of phycobilisomes from nostoc flagelliforme revealed by single particle electron microscopy. | phycobilisomes are protein complexes that harvest light and transfer energy to the photo system. here, the three dimensional structure of intact phycobilisomes from nostoc flagelliforme is studied by a combination of negative stain electron microscopy and cryo-electron microscopy. results show that the intact phycobilisomes are composed of a tricylindrical core and six rods. each allophycocyanin cylinder presents a double-layered structure when viewed from the side and a triangular shape when vi ... | 2005 | 15961084 |
| respiratory cytochrome c oxidase can be efficiently reduced by the photosynthetic redox proteins cytochrome c6 and plastocyanin in cyanobacteria. | plastocyanin and cytochrome c6 are two small soluble electron carriers located in the intrathylacoidal space of cyanobacteria. although their role as electron shuttle between the cytochrome b6f and photosystem i complexes in the photosynthetic pathway is well established, their participation in the respiratory electron transport chain as donors to the terminal oxidase is still under debate. here, we present the first time-resolved analysis showing that both cytochrome c6 and plastocyanin can be ... | 2005 | 15963511 |
| carbohydrate, glycolipid, and lipid components from the photobiont (scytonema sp.) of the lichen, dictyomema glabratum. | the photobiont of the lichen, dictyonema glabratum (scytonema sp.), was isolated and cultivated in a soil-extract medium and submitted to chemical analysis. successive extractions with chcl3-meoh, aqueous meoh, and h2o gave rise to solutions of lipids (25%), low-molecular-weight carbohydrates (22%), and polysaccharides (4%), respectively. tlc of the lipid extract showed the presence of glycolipids, which were further purified and examined by nmr spectroscopy and gc-ms. monogalactosyldiacylglycer ... | 2005 | 15963960 |
| [cloning and analysis of cdna encoding key enzyme gene (dxr) of the non-mva pathway in taxus chinensis cells]. | two distinct routes (classical mevalonate pathway and a novel mevalonate-independent pathway) are utilized by plants for the biosynthesis of isopentenyl diphosphate, the universal precursor of isoprenoids (fig. 1). present researches indicated that taxol was synthesized mainly via non-mevalonate pathway, but not genetic evidence was showed. the second step in non-mevalonate pathway involves an intramolecular rearrangement and subsequent reduction of deoxyxylulose phosphate to yield 2-c-methyl-d- ... | 2004 | 15968987 |
| role of the surface charges d72 and k8 in the function and structural stability of the cytochrome c from nostoc sp. pcc 7119. | we investigated the role of electrostatic charges at positions d72 and k8 in the function and structural stability of cytochrome c6 from nostoc sp. pcc 7119 (cyt c6). a series of mutant forms was generated to span the possible combinations of charge neutralization (by mutation to alanine) and charge inversion (by mutation to lysine and aspartate, respectively) in these positions. all forms of cyt c6 were functionally characterized by laser flash absorption spectroscopy, and their stability was p ... | 2005 | 15978038 |
| mycobacterium tuberculosis serine/threonine kinases pknb, pknd, pkne, and pknf phosphorylate multiple fha domains. | the physiologic roles and the substrates of the mycobacterium tuberculosis (mtb) serine/threonine kinases are largely unknown. here, we report six novel interactions of pknb, pknd, pkne, and pknf with the forkhead-associated (fha) domains of rv0020c and the putative abc transporter rv1747. purified pknb and pknf kinase domains phosphorylated multiple fha-domain proteins in vitro. although they remain to be verified in vivo, these reactions suggest a web of interactions between stpks and fha doma ... | 2005 | 15987910 |
| a high proportion of baltic sea benthic cyanobacterial isolates contain apoptogens able to induce rapid death of isolated rat hepatocytes. | to assess the potential hepatotoxicity of benthic cyanobacteria, we isolated 41 strains from the baltic sea. the bacteria were differentially extracted with solvents of decreasing polarity. the extracts were tested for ability to induce death of primary rat hepatocytes in suspension culture. mainly morphological criteria were used to discriminate between cell death with apoptotic features (shrinkage, chromatin hypercondensation, budding) or necrotic features (swelling, loss of plasma membrane in ... | 2005 | 15990143 |
| distribution and evolution of multiple-step phosphorelay in prokaryotes: lateral domain recruitment involved in the formation of hybrid-type histidine kinases. | although most two-component signal transduction systems use a simple phosphotransfer pathway from one histidine kinase (hk) to one response regulator (rr), a multiple-step phosphorelay involving a phosphotransfer scheme of his-asp-his-asp was also discovered. central to this multiple-step-type signal transduction pathway are a hybrid-type hk, containing both an hk domain and an rr receiver domain in a single protein, and a histidine-containing phosphotransfer (hpt) that can exist either as a dom ... | 2005 | 16000707 |
| the anti-hiv cyanovirin-n domain is evolutionarily conserved and occurs as a protein module in eukaryotes. | a novel protein family homologous to the sugar-binding antiviral protein cyanovirin-n (cvn) is described. cvn, an 11-kda protein that, by binding to the high-mannose moiety of certain viral surface glycoproteins, blocks virus entry into target cells, has thus far been identified only in the cyanobacterium nostoc ellipsosporum. here we show that cvn belongs to a protein family identified by analysis of transcript sequences deriving from a gene expression profiling study conducted in the truffle t ... | 2005 | 16003744 |
| isolation of an antiviral polysaccharide, nostoflan, from a terrestrial cyanobacterium, nostoc flagelliforme. | a novel acidic polysaccharide, nostoflan, was isolated from a terrestrial cyanobacterium, nostoc flagelliforme. nostoflan exhibited a potent anti-herpes simplex virus type 1 (hsv-1) activity with a selectivity index (50% cytotoxic concentration/50% inhibitory concentration against viral replication) of 13,000. sugar composition and methylation analyses revealed that it was mainly composed of -->4)-d-glcp-(1-->, -->6,4)-d-glcp-(1-->, -->4)-d-galp-(1-->, -->4)-d-xylp-(1-->, d-glcap-(1-->, d-manp-( ... | 2005 | 16038544 |
| inhibition of several protein phosphatases by a non-covalently interacting microcystin and a novel cyanobacterial peptide, nostocyclin. | microcystins produced by cyanobacterial 'blooms' in reservoirs and lakes pose significant public health problems because they are highly toxic due to potent inhibition of protein serine/threonine phosphatases in the ppp family. a dehydrobutyrine (dhb)-containing microcystin variant [asp3, admadda5, dhb7]microcystin-htyr isolated from nostoc sp. was found to potently inhibit pp1, pp2a, ppp4 and ppp5 with ic50 values similar to those of microcystin-lr. however, in contrast to microcystin-lr, which ... | 2005 | 16046071 |
| heterocyst-specific excision of the anabaena sp. strain pcc 7120 hupl element requires xisc. | in nitrogen-limiting conditions, approximately 10% of the vegetative cells in filaments of the cyanobacterium anabaena (nostoc) sp. strain pcc 7120 differentiate into nitrogen-fixing heterocysts. during the late stages of heterocyst differentiation, three dna elements, each embedded within an open reading frame, are programmed to excise from the chromosome by site-specific recombination. the dna elements are named after the genes that they interrupt: nifd, fdxn, and hupl. the nifd and fdxn eleme ... | 2005 | 16109944 |
| nitrogen deprivation stimulates symbiotic gland development in gunnera manicata. | gunnera is the only genus of angiosperms known to host cyanobacteria and the only group of land plants that hosts cyanobacteria intracellularly. motile filaments of cyanobacteria, known as hormogonia, colonize gunnera plants through cells in the plant's specialized stem glands. it is commonly held that gunnera plants always possess functional glands for symbiosis. we found, however, that stem gland development did not occur when gunnera manicata plants were grown on nitrogen (n)-replete medium b ... | 2005 | 16113217 |
| toxicity assessment of heavy metals with nostoc muscorum l. | heavy metals in aquatic ecosystem (mn, ni, zn, cu) were tested for their toxicity against nostoc muscorum l., a common fresh water phytoplankton, with respect to chlorophyll, protein, total carbohydrate and starch contents along with growth (od). mn showed stimulatory effect up to 1.5 ppm for all the observed parameters. however, ni, zn and cu (0.1, 0.2, 0.3, 0.4 and 0.5 ppm) showed adverse effects even at 0.1 ppm. chlorophyll was most sensitive parameter followed by carbohydrate, protein and st ... | 2005 | 16114473 |
| laser flash-induced kinetic analysis of cytochrome f oxidation by wild-type and mutant plastocyanin from the cyanobacterium nostoc sp. pcc 7119. | oxidation of the soluble, truncated form of cytochrome f by wild-type and mutant species of plastocyanin has been analyzed by laser flash absorption spectroscopy in the cyanobacterium nostoc (formerly, anabaena) sp. pcc 7119. at low ionic strengths, the apparent electron transfer rate constant of cytochrome f oxidation by wild-type plastocyanin is 1.34 x 10(4) s(-)(1), a value much larger than those determined for the same proteins from other organisms. upon site-directed mutagenesis of specific ... | 2005 | 16114897 |
| the application of micro-ftir spectroscopy to analyze nutrient stress-related changes in biomass composition of phytoplankton algae. | micro-fourier transform infrared (ftir) spectroscopy was used to study changes in spectral features of three species of cyanobacteria (microcystis aeruginosa, croococcus minutus, and nostoc sp.) and two bacillariophyceae (cyclotella meneghiniana, and phaeodactylum tricornutum) in response to nutrient stress. the change of physiological state of the cells was followed during a 4-week starvation period on the basis of physiological key parameters and by means of ftir spectroscopy. changes in the i ... | 2005 | 16122937 |
| clustered genes required for synthesis and deposition of envelope glycolipids in anabaena sp. strain pcc 7120. | photoreduction of dinitrogen by heterocyst-forming cyanobacteria is of great importance ecologically and for subsistence rice agriculture. their heterocysts must have a glycolipid envelope layer that limits the entry of oxygen if nitrogenase is to remain active to fix dinitrogen in an oxygen-containing milieu (the fox+ phenotype). genes alr5354 (hgld), alr5355 (hglc) and alr5357 (hglb) of the filamentous cyanobacterium, anabaena sp. strain pcc 7120, and hgle of nostoc punctiforme are required fo ... | 2005 | 16164561 |
| cyanopeptolin 954, a chlorine-containing chymotrypsin inhibitor of microcystis aeruginosa niva cya 43. | a new depsipeptide, cyanopeptolin 954 (1), was isolated from the freshwater cyanobacterium microcystis aeruginosa niva cya 43. the structure of the compound was elucidated by chemical and spectroscopic analyses, including 2d nmr and gc-ms of the hydrolysate. the major structural differences compared to previously characterized heptadepsipeptides of microcystis are the replacement of the basic amino acid in position 4 by l-leucine, the presence of l-phenylalanine in position 6, and the uncommon r ... | 2005 | 16180807 |
| uv irradiation and desiccation modulate the three-dimensional extracellular matrix of nostoc commune (cyanobacteria). | cyanobacterium nostoc commune can tolerate the simultaneous stresses of desiccation, uv irradiation, and oxidation. acidic wspa, of approximately 33.6 kda, is secreted to the three-dimensional extracellular matrix and accounts for greater than 70% of the total soluble protein. the wspa gene of n. commune strain drh1 was cloned and found in a single genomic copy, in a monocistronic operon. transcription of wspa and sodf (superoxide dismutase), and synthesis and secretion of wspa, were induced upo ... | 2005 | 16192267 |
| a brownian dynamics study of the interaction of phormidium cytochrome f with various cyanobacterial plastocyanins. | brownian dynamics simulations were used to study the role of electrostatic forces in the interactions of cytochrome f from the cyanobacterium phormidium laminosum with various cyanobacterial plastocyanins. both the net charge on the plastocyanin molecule and the charge configuration around h92 (h87 in higher plants) are important in determining the interactions. those plastocyanins (pcs) with a net charge more negative than -2.0, including those from synechococcus sp. pcc7942, synechocystis sp. ... | 2006 | 16214856 |
| an overview of the genome of nostoc punctiforme, a multicellular, symbiotic cyanobacterium. | nostoc punctiforme is a filamentous cyanobacterium with extensive phenotypic characteristics and a relatively large genome, approaching 10 mb. the phenotypic characteristics include a photoautotrophic, diazotrophic mode of growth, but n. punctiforme is also facultatively heterotrophic; its vegetative cells have multiple developmental alternatives, including terminal differentiation into nitrogen-fixing heterocysts and transient differentiation into spore-like akinetes or motile filaments called ... | 2001 | 16228364 |
| bioactivities of nostocine a produced by a freshwater cyanobacterium nostoc spongiaeforme tistr 8169. | a freshwater cyanobacterium, nostoc spongiaeforme tistr 8169, synthesizes and releases a violet pigment, nostocine a, into medium. we examined the bioactivity of nostocine a to several model organisms breeding with n. spongiaeforme in the natural environment. to microalgae, nostocine a exhibited growth inhibitory activity comparable to paraquat, and the activity tended to be stronger to green algae than to cyanobacteria. nostocine a also exhibited strong inhibitory activity to the root elongatio ... | 2003 | 16233448 |
| the cyanobacterium anabaena sp. pcc 7120 has two distinct beta-carotene ketolases: crto for echinenone and crtw for ketomyxol synthesis. | two beta-carotene ketolases, crtw and crto, are widely distributed in bacteria, although they show no significant sequence homology with each other. the cyanobacterium anabaena sp. pcc 7120 was found to have two homologous genes. in the crtw deleted mutant, myxol 2'-fucoside was present, but ketomyxol 2'-fucoside was absent. in the crto deleted mutant, beta-carotene was accumulated, and the amount of echinenone was decreased. therefore, crtw catalyzed myxol 2'-fucoside to ketomyxol 2'-fucoside, ... | 2005 | 16242129 |
| modulation of carbonic anhydrase activity in two nitrogen fixing cyanobacteria, nostoc calcicola and anabaena sp. | the activity of enzyme carbonic anhydrase (ca) was investigated in two diazotrophic cyanobacteria, anabaena sp. (arm 629) and nostoc calcicola, in the presence of co2/nahco3 and different inhibitors. the ca activity increased when the cells were pretreated with a high concentration of co2/nahco3 and then transferred to ambient level co2. maximum activity of ca was observed after 8 h of incubation in light on transfer of cells from high ci to ambient level co2, and was low when incubated in dark. ... | 2005 | 16255166 |
| partial characterization of extracellular polysaccharides from cyanobacteria. | four cyanobacterial strains, cyanothece sp., oscillatoria sp., nostoc sp. and nostoc carneum were studied for physico-chemical characterization of extracellular polysaccharide (eps) secreted during the controlled growth condition. hydrolyzed epss showed the compositional involvement of four sugar moieties viz. mannose, glucose, xylose and ribose in varying combinations. infrared spectra of epss showed a specific absorbance of o-h stretching at 3448-3400 cm(-1), asymmetrical-symmetrical c-h stret ... | 2006 | 16256343 |
| sucrose synthase and rubisco expression is similarly regulated by the nitrogen source in the nitrogen-fixing cyanobacterium anabaena sp. | in higher plants and cyanobacteria, sucrose (suc) metabolism is carried out by a similar set of enzymes. the function and regulation of suc metabolism in cyanobacteria has begun to be elucidated. in strains of anabaena sp., filamentous nitrogen-fixing cyanobacteria, suc synthase (sus, ec 2.4.1.13) controls suc cell level through the cleavage of the disaccharide. the present work shows that there are two sus genes in anabaena (nostoc) sp. that are co-regulated regarding the nitrogen source; howev ... | 2006 | 16261375 |
| physiological and molecular diversity of feather moss associative n2-fixing cyanobacteria. | cyanobacteria colonizing the feather moss pleurozium schreberi were isolated from moss samples collected in northern sweden and subjected to physiological and molecular characterization. morphological studies of isolated and moss-associated cyanobacteria were carried out by light microscopy. molecular tools were used for cyanobacteria identification, and a reconstitution experiment of the association between non-associative mosses and cyanobacteria was conducted. the influence of temperature on ... | 2005 | 16263908 |
| crucial role of extracellular polysaccharides in desiccation and freezing tolerance in the terrestrial cyanobacterium nostoc commune. | the cyanobacterium nostoc commune is adapted to the terrestrial environment and has a cosmopolitan distribution. in this study, the role of extracellular polysaccharides (eps) in the desiccation tolerance of photosynthesis in n. commune was examined. although photosynthetic o2 evolution was not detected in desiccated colonies, the ability of the cells to evolve o2 rapidly recovered after rehydration. the air-dried colonies contained approximately 10% (wt/wt) water, and field-isolated, natural co ... | 2005 | 16269775 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| phytochelatin synthase, papain's cousin, in stereo. | | 2006 | 16407124 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| molecular mechanisms in the nitrogen-fixing nostoc-bryophyte symbiosis. | | 2006 | 16623394 |
| studies on the photosynthetic reaction. ii. sodium formate and urea feeding experiments with nostoc muscorum. | | 1954 | 16654631 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |