Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| production and characterization of antimicrobial active substance from the cyanobacterium nostoc muscorum. | in this investigation, the cyanobacterium nostoc muscorum exhibited antagonistic activity against gram-positive and gram-negative bacteria and filamentous fungi. the results indicated that the active substance produced maximally after 12 days of incubation in shaken culture at 35-¦c, at ph 8.0 in bg-11 medium. the increase in nitrate concentration of the medium led to an increase in the antimicrobial production. chloroform was the best solvent for extracting the active material. the antagonistic ... | 2006 | 21783637 |
| structure and development of nostoc strands in leiosporoceros dussii (anthocerotophyta): a novel symbiosis in land plants. | the presence of nostoc in longitudinally oriented schizogenous canals is a feature that separates leiosporoceros from all other hornworts and represents a novel symbiotic arrangement in land plants. in surface view, nostoc canals are visible as elongated, dichotomously branched blue-green strands. all other hornworts develop numerous discrete globose colonies through continuous production of mucilage clefts as avenues for multiple invasions within a single thallus. to elucidate the anatomy and d ... | 2006 | 21642133 |
| molecular mechanisms in the nitrogen-fixing nostoc-bryophyte symbiosis. | 2006 | 16623394 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| proteomic analyses of the photoauto- and diazotrophically grown cyanobacterium nostoc sp. pcc 73102. | the filamentous cyanobacteria of the genus nostoc are globally distributed, phenotypically complex organisms, capable of cellular differentiation and of forming symbiotic associations with a wide range of plants. to further our understanding of these processes and functions, the proteome of photoautotrophically and diazotrophically grown nostoc sp. pcc 73102 (n. punctiforme) cells was examined. extracted proteins were separated into membrane and soluble protein fractions and analysed using two-d ... | 2007 | 17259633 |
| an itraq-based quantitative analysis to elaborate the proteomic response of nostoc sp. pcc 7120 under n2 fixing conditions. | nostoc sp. pcc 7120 is an oxygen-evolving photoautotrophic n2 fixing filamentous cyanobacterium. upon nitrogen starvation, a range of processes are initiated, such as differentiation of the heterocysts, specific cells where n2 fixation takes place. we have characterized and quantified the proteome of the nostoc sp. pcc 7120 wild-type strain grown under n2 fixing and non-n2 fixing conditions. to assess global proteome changes in response to environmental changes, measurements were made using the ... | 2007 | 17269719 |
| insight into the radical mechanism of phycocyanobilin-ferredoxin oxidoreductase (pcya) revealed by x-ray crystallography and biochemical measurements. | the x-ray crystal structure of the substrate-free form of phycocyanobilin (pcb)-ferredoxin oxidoreductase (pcya; ec 1.3.7.5) from the cyanobacterium nostoc sp. pcc7120 has been solved at 2.5 a resolution. a comparative analysis of this structure with those recently reported for substrate-bound and substrate-free forms of pcya from the cyanobacterium synechocystis sp. pcc6803 (hagiwara et al. (2006) proc. natl. acad. sci. u.s.a. 103, 27-32; hagiwara et al. (2006) febs lett. 580, 3823-3828) provid ... | 2007 | 17279614 |
| carbamidocyclophanes a-e, chlorinated paracyclophanes with cytotoxic and antibiotic activity from the vietnamese cyanobacterium nostoc sp. | five new paracyclophanes, carbamidocyclophanes a-e (1-5), characterized by carbamido side chains at a symmetric [7.7]paracyclophane ring, have been isolated from the biomass of the vietnamese nostoc sp. cavn 10. structure elucidation by spectroscopic methods showed that 1-5 vary in the substitution pattern of the chlorinated butyl side chains. the compounds exhibited cytotoxic activity against mcf-7 (breast cancer cell line) and fl cells (human amniotic epithelial cell line) and moderate antibac ... | 2007 | 17311455 |
| mutations stabilize small subunit ribosomal rna in desiccation-tolerant cyanobacteria nostoc. | the ribosomal rna molecule is an ideal model for evaluating the stability of a gene product under desiccation stress. we isolated 8 nostoc strains that had the capacity to withstand desiccation in habitats and sequenced their 16s rrna genes. the stabilities of 16s rrnas secondary structures, indicated by free energy change of folding, were compared among nostoc and other related species. the results suggested that 16s rrna secondary structures of the desiccation-tolerant nostoc strains were more ... | 2007 | 17334839 |
| cofactor regeneration in phototrophic cyanobacteria applied for asymmetric reduction of ketones. | the obligate photoautotrophic cyanobacterium synechococcus pcc7942 and the photoheterotrophic heterocystous cyanobacterium noctoc muscorum are able to reduce prochiral ketones asymmetrically to optical pure chiral alcohols without light. an example is the synthesis of s-pentafluoro(phenyl-)ethanol with an enantiomeric excess >99% if 2'-3'-4'-5'-6'-pentafluoroacetophenone is used as substrate. if no light is available for regeneration of the cofactor nicotinamide adenine dinucleotide phosphate (r ... | 2007 | 17345080 |
| fura modulates gene expression of alr3808, a dpsa homologue in nostoc (anabaena) sp. pcc7120. | the dna-binding protein from stationary phase (dps) protein family plays an important role in protecting microorganisms from oxidative and nutritional stresses. in silico analysis of the promoter region of alr3808, a dpsa homologue from the cyanobacterium nostoc sp. pcc7120 shows putative iron-boxes with high homology with those recognized by fura (ferric uptake regulator). evidence for the modulation of dpsa by fura was obtained using in vitro and in vivo approaches. selex linked to pcr was use ... | 2007 | 17350003 |
| molecular genetics and genomic analysis of scytonemin biosynthesis in nostoc punctiforme atcc 29133. | the indole-alkaloid scytonemin is the most common and widespread sunscreen among cyanobacteria. previous research has focused on its nature, distribution, ecology, physiology, and biochemistry, but its molecular genetics have not been explored. in this study, a scytonemin-deficient mutant of the cyanobacterium nostoc punctiforme atcc 29133 was obtained by random transposon insertion into open reading frame npr1273. the absence of scytonemin under conditions of induction by uv irradiation was the ... | 2007 | 17351042 |
| cloning of lipoxygenase genes from a cyanobacterium, nostoc punctiforme, and its expression in eschelichia coli. | oxylipin metabolism represents one of the important hormonal and defensive mechanisms employed by plants, algae, or animals. it begins mostly with the reaction of lipoxygenases (loxs), which catalyze the oxygenation of polyunsaturated fatty acids to form the corresponding hydroperoxides. at present, little information about loxs in cyanobacteria has been reported. herein, we report the first isolation of two lox genes (nplox1 and nplox2) from a cyanobacterium, nostoc punctiforme atcc29133. incub ... | 2007 | 17375360 |
| group 3 sigma factor gene, sigj, a key regulator of desiccation tolerance, regulates the synthesis of extracellular polysaccharide in cyanobacterium anabaena sp. strain pcc 7120. | the changes in the expression of sigma factor genes during dehydration in terrestrial nostoc hk-01 and aquatic anabaena pcc 7120 were determined. the expression of the sigj gene in terrestrial nostoc hk-01, which is homologous to sigj (alr0277) in aquatic anabaena pcc 7120, was significantly induced in the mid-stage of dehydration. we constructed a higher-expressing transformant of the sigj gene (he0277) in anabaena pcc 7120, and the transformant acquired desiccation tolerance. the results of an ... | 2007 | 17376888 |
| three distinct clades of cultured heterocystous cyanobacteria constitute the dominant n2-fixing members of biological soil crusts of the colorado plateau, usa. | the identity of the numerically dominant n(2)-fixing bacteria in biological soil crusts of the colorado plateau region and two outlying areas was determined using multiple approaches, to link the environmental diversity of nifh gene sequences to cultured bacterial isolates from the regions. of the nifh sequence-types detected in soil crusts of the colorado plateau, 89% (421/473) were most closely related to nifh signature sequences from cyanobacteria of the order nostocales. n(2)-fixing cyanobac ... | 2007 | 17381526 |
| structural characterization of the fusion of two pentapeptide repeat proteins, np275 and np276, from nostoc punctiforme: resurrection of an ancestral protein. | the nostoc punctiforme genes np275 and np276 are two adjacently encoded proteins of 98 and 75 amino acids in length and exhibit sequences composed of tandem pentapeptide repeats. the structures of np275 and a fusion of np275 and np276 were determined to 2.1 and 1.5 a, respectively. the two nostoc proteins fold as highly symmetric right-handed quadrilateral beta-helices similar to the mycobacterial protein mfpa implicated in fluoroquinolone resistance and dna gyrase inhibition. the sequence compo ... | 2007 | 17384236 |
| anti-proliferative effects of recombinant iron superoxide dismutase on hepg2 cells via a redox-dependent pi3k/akt pathway. | the coding sequence for an iron superoxide dismutase (fe-sod) was amplified from the nostoc commune genome. recombinant fe-sod was overexpressed in escherichia coli, accounting for approximately 76% of total bacterial protein. fe-sod was purified from bacterial lysate by ni-nta column chromatography and used to generate an anti-sod antibody. the purified fe-sod was encapsulated in liposomes and delivered to hepg2 liver tumor cells to eliminate cellular superoxide anions. the sod-loaded cells exh ... | 2007 | 17387468 |
| biosorption of cr(vi) by immobilized biomass of two indigenous strains of cyanobacteria isolated from metal contaminated soil. | biosorption of cr(vi) using native strains of cyanobacteria from metal contaminated soil in the premises of textile mill has been reported in this paper. biosorption was studied as a function of ph (1-5), contact time (5-180 min) and initial chromium ion concentration (5-20mg/l) to find out the maximum biosorption capacity of alginate immobilized nostoc calcicola hh-12 and chroococcus sp. hh-11. the optimum conditions for cr(vi) biosorption are almost same for the two strains (ph 3-4, contact ti ... | 2007 | 17403568 |
| m. tuberculosis ser/thr protein kinase d phosphorylates an anti-anti-sigma factor homolog. | receptor ser/thr protein kinases are candidates for sensors that govern developmental changes and disease processes of mycobacterium tuberculosis (mtb), but the functions of these kinases are not established. here, we show that mtb protein kinase (pkn) d overexpression alters transcription of numerous bacterial genes, including rv0516c, a putative anti-anti-sigma factor, and genes regulated by sigma factor f. the pknd kinase domain directly phosphorylated rv0516c, but no other sigma factor regul ... | 2007 | 17411339 |
| oxylipin formation in nostoc punctiforme (pcc73102). | the dioxygenation of polyunsaturated fatty acids is mainly catalyzed by members of the lipoxygenase enzyme family in flowering plants and mosses. lipoxygenase products can be metabolized further and are known as signalling substances that play a role in plant development as well as in plant responses to wounding and pathogen attack. apart from accumulating data in mammals, flowering and non-flowering plants, information on the relevance of lipid peroxide metabolism in prokaryotic organisms is sc ... | 2007 | 17412376 |
| molecular analysis of genes in nostoc punctiforme involved in pilus biogenesis and plant infection. | hormogonia are the infective agents in many cyanobacterium-plant symbioses. pilus-like appendages are expressed on the hormogonium surface, and mutations in pil-like genes altered surface piliation and reduced symbiotic competency. this is the first molecular evidence that pilus biogenesis in a filamentous cyanobacterium requires a type iv pilus system. | 2007 | 17416648 |
| the anabaena sp. strain pcc 7120 asr1734 gene encodes a negative regulator of heterocyst development. | the novel asr1734 gene of anabaena (nostoc) sp. strain pcc 7120 inhibited heterocyst development when present in extra copies. overexpression of asr1734 inhibited heterocyst development in several strains including the wild type and two strains that form multiple contiguous heterocysts (mch phenotype): a pats null mutant and a hetr(r223w) mutant. overexpression of asr1734 also caused increased nbla messenger rna levels, and increased loss of autofluorescence in vegetative cells throughout filame ... | 2007 | 17462023 |
| global gene expression patterns of nostoc punctiforme in steady-state dinitrogen-grown heterocyst-containing cultures and at single time points during the differentiation of akinetes and hormogonia. | the vegetative cells of the filamentous cyanobacterium nostoc punctiforme can differentiate into three mutually exclusive cell types: nitrogen-fixing heterocysts, spore-like akinetes, and motile hormogomium filaments. a dna microarray consisting of 6,893 n. punctiforme genes was used to identify the global transcription patterns at single time points in the three developmental states, compared to those in ammonium-grown time zero cultures. analysis of ammonium-grown cultures yielded a transcript ... | 2007 | 17483217 |
| reconstitution of modular pdk1 functions on trans-splicing of the regulatory ph and catalytic kinase domains. | the serine-threonine protein kinases pdk1 and pkb each contain a pleckstrin homology (ph) domain that binds the membrane-bound phosphatidylinositol 3,4,5-triphosphate [pi(3,4,5)p3] second messenger and is required for pdk1-catalyzed phosphorylation and activation of pkb. while x-ray structures have been reported for the individual regulatory ph and catalytic kinase domain constructs of both pdk1 and pkb, diffraction quality crystals of full length constructs have yet to be obtained, likely due t ... | 2007 | 17500509 |
| effects of periodic desiccation on the synthesis of the uv-screening compound, scytonemin, in cyanobacteria. | scytonemin is an ultraviolet radiation (uvr)-screening compound synthesized by some sheathed cyanobacteria exposed to high solar and sky radiation. it is primarily produced in response to uva radiation, but certain environmental stresses can enhance synthesis. this study focuses on the effects of periodic desiccation on scytonemin synthesis in three desiccation-tolerant cyanobacterial strains, nostoc punctiforme pcc 73102, chroococcidiopsis ccmee 5056 and chroococcidiopsis ccmee 246. nostoc punc ... | 2007 | 17504482 |
| l-amino acid oxidases with specificity for basic l-amino acids in cyanobacteria. | the two closely related fresh water cyanobacteria synechococcus elongatus pcc 6301 and synechococcus elongatus pcc 7942 have previously been shown to constitutively express a fad-containing l-amino acid oxidase with high specificity for basic l-amino acids (l-arginine being the best substrate). in this paper we show that such an enzyme is also present in the fresh water cyanobacterium synechococcus cedrorum pcc 6908. in addition, an improved evaluation of the nucleotide/amino acid sequence of th ... | 2007 | 17542496 |
| purification and characterization of corrinoid-compounds from the dried powder of an edible cyanobacterium, nostoc commune (ishikurage). | vitamin b12 content (98.8 +/- 5.6 microg/100 g dry weight) of an edible cyanobacterium, nostoc commune (ishikurage) was determined by the lactobacillus delbrueckii atcc 7830 microbiological method. bioautography with vitamin b12-dependent escherichia coli 215 indicated that n. commune contained two (main and minor) corrinoid-compounds. these corrinoid-compounds were purified to homogeneity from the dried algal cells and characterized. the main and minor purified corrinoid-compounds were identifi ... | 2007 | 17616007 |
| transcription and regulation of the bidirectional hydrogenase in the cyanobacterium nostoc sp. strain pcc 7120. | the filamentous, heterocystous cyanobacterium nostoc sp. strain pcc 7120 (anabaena sp. strain pcc 7120) possesses an uptake hydrogenase and a bidirectional enzyme, the latter being capable of catalyzing both h2 production and evolution. the completely sequenced genome of nostoc sp. strain pcc 7120 reveals that the five structural genes encoding the bidirectional hydrogenase (hoxefuyh) are separated in two clusters at a distance of approximately 8.8 kb. the transcription of the hox genes was exam ... | 2007 | 17630298 |
| desensitization of soluble guanylyl cyclase, the no receptor, by s-nitrosylation. | the molecular mechanism of desensitization of soluble guanylyl cyclase (sgc), the no receptor, has long remained unresolved. posttranslational modification and redox state have been postulated to affect sgc sensitivity to no but evidence has been lacking. we now show that sgc can be s-nitrosylated in primary aortic smooth muscle cells by s-nitrosocysteine (csno), an s-nitrosylating agent, in human umbilical vein endothelial cells after vascular endothelial growth factor treatment and in isolated ... | 2007 | 17636120 |
| anti-herpes simplex virus target of an acidic polysaccharide, nostoflan, from the edible blue-green alga nostoc flagelliforme. | the acidic polysaccharide nostoflan was previously isolated as an antiviral component from the terrestrial alga nostoc flagelliforme. in the present study, we examined the target for its anti-herpes simplex virus type 1 action. in time-of-addition experiments, the most sensitive stage of viral replication to nostoflan was found to be early events, including the virus binding and/or penetration processes. in order to determine what extent nostoflan may be involved in these processes, virus bindin ... | 2007 | 17666824 |
| nanoscale visualization of a fibrillar array in the cell wall of filamentous cyanobacteria and its implications for gliding motility. | many filamentous cyanobacteria are motile by gliding, which requires attachment to a surface. there are two main theories to explain the mechanism of gliding. according to the first, the filament is pushed forward by small waves that pass along the cell surface. in the second, gliding is powered by the extrusion of slime through pores surrounding each cell septum. we have previously shown that the cell walls of several motile cyanobacteria possess an array of parallel fibrils between the peptido ... | 2007 | 17693519 |
| desaturase genes in a psychrotolerant nostoc sp. are constitutively expressed at low temperature. | antarctic psychrotolerant, nostoc sp. (so-36), when grown at 25 degrees c and then shifted to 10 degrees c, showed an increase in the tri-unsaturated fatty acid [c(18:3(9,12,15))] at the expense of mono- [c(18:1(9))] and di-unsaturated [c(18:2(9,12))] fatty acids. these results indicate that the activities of the enzymes desa and desb are up-regulated, when cultures were grown at 10 degrees c or shifted to 10 degrees c from 25 degrees c. however, rt-pcr studies indicated a constitutive expressio ... | 2007 | 17697671 |
| 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 |
| 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 |
| 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 |
| lyase activities of cpcs- and cpct-like proteins from nostoc pcc7120 and sequential reconstitution of binding sites of phycoerythrocyanin and phycocyanin beta-subunits. | genes all5292 (cpcs2) and alr0617 (cpcs1) in the cyanobacterium nostoc pcc7120 are homologous to the biliprotein lyase cpcs, and genes all5339 (cpct1) and alr0647 (cpct2) are homologous to the lyase cpct. the functions of the encoded proteins were screened in vitro and in a heterologous escherichia coli system with plasmids conferring biosynthesis of the phycocyanobilin chromophore and of the acceptor proteins beta-phycoerythrocyanin (pecb) or beta-phycocyanin (cpcb). cpct1 is a regioselective b ... | 2007 | 17895251 |
| recurrent adenylation domain replacement in the microcystin synthetase gene cluster. | microcystins are small cyclic heptapeptide toxins produced by a range of distantly related cyanobacteria. microcystins are synthesized on large nrps-pks enzyme complexes. many structural variants of microcystins are produced simultaneously. a recombination event between the first module of mcyb (mcyb1) and mcyc in the microcystin synthetase gene cluster is linked to the simultaneous production of microcystin variants in strains of the genus microcystis. | 2007 | 17908306 |
| cross-talk between iron and nitrogen regulatory networks in anabaena (nostoc) sp. pcc 7120: identification of overlapping genes in fura and ntca regulons. | nitrogen signalling in cyanobacteria involves a complex network in which the availability of iron plays an important role. in the nitrogen-fixing cyanobacterium anabaena sp. pcc 7120, iron uptake is controlled by fura, while ntca is the master regulator of nitrogen metabolism and shows a mutual dependence with hetr in the first steps of heterocyst development. expression of fura is modulated by ntca and it is enhanced in a hetr(-) background. iron starvation in cells grown in the presence of com ... | 2007 | 17920076 |
| effects of disruption of homocitrate synthase genes on nostoc sp. strain pcc 7120 photobiological hydrogen production and nitrogenase. | in the case of nitrogenase-based photobiological hydrogen production systems of cyanobacteria, the inactivation of uptake hydrogenase (hup) leads to significant increases in hydrogen production activity. however, the high-level-activity stage of the hup mutants lasts only a few tens of hours under air, a circumstance which seems to be caused by sufficient amounts of combined nitrogen supplied by active nitrogenase. the catalytic femo cofactor of nitrogenase binds homocitrate, which is required f ... | 2007 | 17933939 |
| structural and functional characterization of galactooligosaccharides in nostoc commune: beta-d-galactofuranosyl-(1-->6)-[beta-d-galactofuranosyl-(1-->6)]2-beta-d-1,4-anhydrogalactitol and beta-(1-->6)-galactofuranosylated homologues. | a new class of galactooligosaccharides has been identified from the terrestrial cyanobacterium nostoc commune by ms and nmr techniques. these consist of beta-d-galactofuranosyl-(1-->6)-[beta-d-galactofuranosyl-(1-->6)]n-beta-d-1,4-anhydrogalactitols with n ranging from 2 to 8, corresponding to compounds designated 1 through 7. in total these saccharides amounted to approximately 0.35% of the dry thallus of n. commune, while in several other cyanobacteria they were not detected. possibly they pla ... | 2007 | 17935705 |
| a gene cluster that regulates both heterocyst differentiation and pattern formation in anabaena sp. strain pcc 7120. | wild-type anabaena sp. strain pcc 7120, a filamentous nitrogen-fixing cyanobacterium, produces single heterocysts at semi-regular intervals. asr0100 (patu5) and alr0101 (patu3) are homologous to the 5' and 3' portions of patu of nostoc punctiforme. alr0099 (hetz) overlaps the 5' end of patu5. hetz, patu5 and patu3 were all upregulated, or expressed specifically, in proheterocysts and heterocysts. mutants of hetz showed delayed or no heterocyst differentiation. in contrast, a patu3 mutation produ ... | 2007 | 18045384 |
| isolation and characterization of thylakoid membranes from the filamentous cyanobacterium nostoc punctiforme. | nostoc punctiforme strain pasteur culture collection (pcc) 73102, a sequenced filamentous cyanobacterium capable of nitrogen fixation, is used as a model organism for characterization of bioenergetic processes during nitrogen fixation in nostoc. a protocol for isolating thylakoid membranes was developed to examine the biochemical and biophysical aspects of photosynthetic electron transfer. thylakoids were isolated from filaments of n. punctiforme by pneumatic pressure-drop lysis. the activity of ... | 2007 | 18251853 |
| free radical scavenging and antioxidant enzymes activation of polysaccharide extract from nostoc sphaeroides. | nostoc sphaeroides kuetzing has been used as a traditional medicine in china to treat a variety of ailments. this research identified the antioxidant activities of polysaccharide extract from nostoc sphaeroides. the extract, which contains 46.2% carbohydrates, exhibited an effective scavenging capability on superoxide radical, hydroxyl radicals in non site-specific as well as site-specific assays, and also performed lipid peroxidation inhibition in a dose-dependent manner. polysaccharide extract ... | 2007 | 17963327 |
| effect of uv-b and high visual radiation on photosynthesis in freshwater (nostoc spongiaeforme) and marine (phormidium corium) cyanobacteria. | human activity is causing depletion of ozone in stratosphere, resulting in increased uv-b radiation and global warming. however, impact of these climatic changes on the aquatic organism (especially marine) is not fully understood. here, we have studied the effect of excess uv-b and visible radiation on photosynthetic pigments, fatty acids content, lipid peroxidation, nitrogen content, nitrogen reductase activity and membrane proteins, induction of mycosporine-like amino acids (maas) and antioxid ... | 2007 | 17970281 |
| biological control of faba bean pathogenic fungi by three cyanobacterial filtrates. | the aim of the present study is to evaluate the biological control aptitude of the cyanobacteria, anabaena subcylindrica, nostoc muscorum and oscillatoria angusta filtrates on the growth of the isolated pathogenic fungi from the different organs of faba bean. three caynobacterial (anabaena subcylindrica, nostoc muscorum and oscillatoria angusta) filtrates were prepared in different concentrations and their effects on the isolated pathogenic fungi from leaves, stems and roots of faba bean were st ... | 2007 | 19090096 |
| preliminary survey of edaphic algae in al-hasa region, saudi arabia. | five soil samples were taken from different cultivated sites from the north villages of al-hasa. three algal groups were recorded throughout this study, bacillariophyta, cyanophyta and chlorophyta. fifty-two genera of algae were identified in all the soils sampled during this investigation. out of these, 11 genera belonged to the chlorophyta; 16 genera belong to bacillariophyta and 25 genera to cyanophyta. penniate bacillariophyta (nitzschia, gyrosigma), oscillatorid cyanophyta (osillatoria, pho ... | 2007 | 19090128 |
| endothelial cell-based methods for the detection of cyanobacterial anti-inflammatory and wound-healing promoting metabolites. | acute lung injury is accompanied by an increased endothelial chemokine production and adhesion molecule expression, which may result in an extensive neutrophil infiltration. moreover, a destruction of the alveolar epithelium and capillary endothelium may result in permeability edema. as such, the search for novel anti-inflammatory substances, able to downregulate these parameters as well as the tissue damage holds therapeutic promise. we therefore describe here the use of human endothelial cell- ... | 2007 | 19356051 |
| production of the neurotoxin bmaa by a marine cyanobacterium. | diverse species of cyanobacteria have recently been discovered to produce the neurotoxic non-protein amino acid beta-methylamino-l-alanine (bmaa). in guam, bmaa has been studied as a possible environmental toxin in the diets of indigenous chamorro people known to have high levels of amyotrophic lateral sclerosis/ parkinsonism dementia complex (als/pdc). bmaa has been found to accumulate in brain tissues of patients with progressive neurodegenerative illness in north america. in guam, bmaa was fo ... | 2007 | 18463731 |
| identification and expression analyses of putative sesquiterpene synthase genes in phormidium sp. and prevalence of geoa-like genes in a drinking water reservoir. | the occurrence of taste and odor problems in drinking water supplies is a widespread phenomenon. from a saxonian water reservoir we isolated a cyanobacterial species which was classified as phormidium sp. under laboratory conditions it produced an earthy-musty smell due to the synthesis of geosmin. the only genes shown to be involved in geosmin biosynthesis are cyc2 and geoa of streptomyces. based on the alignment of cyc2 with a putative sesquiterpene synthase of nostoc punctiforme, a degenerate ... | 2007 | 17827321 |
| 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 |
| 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 |
| 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 |
| 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 |