Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| nested evolution of a trna(leu)(uaa) group i intron by both horizontal intron transfer and recombination of the entire trna locus. | the origin and evolution of bacterial introns are still controversial issues. here we present data on the distribution and evolution of a recently discovered divergent trna(leu)(uaa) intron. the intron shows a higher sequence affiliation with introns in trna(ile)(cau) and trna(arg)(ccu) genes in alpha- and beta-proteobacteria, respectively, than with other cyanobacterial trna(leu)(uaa) group i introns. the divergent trna(leu)(uaa) intron is sporadically distributed both within the nostoc and the ... | 2002 | 11790735 |
| establishment of a functional symbiosis between the cyanobacterium nostoc punctiforme and the bryophyte anthoceros punctatus requires genes involved in nitrogen control and initiation of heterocyst differentiation. | three mutant strains (ntca, hetr, hetf) of the cyanobacterium nostoc punctiforme unable to differentiate heterocysts were characterized and examined for their ability to form a symbiotic association with the bryophyte anthoceros punctatus. previously unknown characteristics of the n. punctiforme hetr mutant include differentiation of chilling-resistant akinetes, while vegetative cells of the ntca mutant randomly lysed, yielding short filaments, following ammonium deprivation. strains with mutati ... | 2002 | 11782524 |
| transcriptional regulation of nostoc hydrogenases: effects of oxygen, hydrogen, and nickel. | the transcription of structural genes encoding two hydrogenases in n(2)-fixing cultures of the cyanobacteria nostoc muscorum and nostoc sp. strain pcc 73102 were examined by reverse transcription-pcr. a low level of oxygen and addition of nickel induce higher transcript levels of both hydrogenases, whereas molecular hydrogen has a positive effect on the transcription of the genes encoding only the uptake hydrogenase. | 2002 | 11772661 |
| cloning, characterization, and functional expression in escherichia coli of argh encoding argininosuccinate lyase in the cyanobacterium nostoc sp. strain pcc 73102. | a gene argh, encoding argininosuccinate lyase (asl), has been cloned from a cosmid library of the filamentous cyanobacterium nostoc sp. strain pcc 73102. the argh open reading frame encodes a protein comprised of 461 amino acids with a calculated molecular mass of 51,349 da. protein sequence comparisons reveal significant similarities of the nostoc pcc 73102 asl to related proteins from other organisms. in an escherichia coli delta argh strain, the nostoc pcc 73102 asl expressed from a recombina ... | 2001 | 11683360 |
| cellulose in cyanobacteria. origin of vascular plant cellulose synthase? | although cellulose biosynthesis among the cyanobacteria has been suggested previously, we present the first conclusive evidence, to our knowledge, of the presence of cellulose in these organisms. based on the results of x-ray diffraction, electron microscopy of microfibrils, and cellobiohydrolase i-gold labeling, we report the occurrence of cellulose biosynthesis in nine species representing three of the five sections of cyanobacteria. sequence analysis of the genomes of four cyanobacteria revea ... | 2001 | 11598227 |
| form species nostoc commune (cyanobacteria). | the form species concept for the cyanobacteria was evaluated using a comprehensive set of nostoc samples that were collected during the past two centuries, from all continents, including regions from the tropics to the poles. phylogenies were constructed based upon the conserved regions of trnaleu (uaa) group i intron dna sequences. thirty-four forms contained a trnaleu (uaa) intron of 284 nt. these 284-nt introns contained 200 nt of conserved sequence that, in most cases, shared 100% sequence i ... | 2001 | 11594617 |
| cyanobacteria in uruguayan rice fields: diversity, nitrogen fixing ability and tolerance to herbicides and combined nitrogen. | it has been established that cyanobacteria play a vital role in the maintenance of flooded rice field fertility. to evaluate the potential use of nitrogen-fixing cyanobacteria as a natural biofertilizer for rice in uruguay, the diversity, abundance and nitrogen fixing ability of these microorganisms were studied in the field and in the laboratory. the effect of urea fertilization on population density and diversity of heterocystous cyanobacteria was determined on a 3-year assay. the highest numb ... | 2001 | 11566382 |
| [microbiota of the orchid rhizoplane]. | six bacterial strains isolated from the underground roots of the terrestrial orchid calanthe vestita var. rubrooculata were found to belong to the genera arthrobacter, bacillus, mycobacterium, and pseudomonas. strains isolated from the aerial roots of the epiphytic orchid dendrobium moschatum were classified into the genera bacillus, curtobacterium, flavobacterium, nocardia, pseudomonas, rhodococcus, and xanthomonas. the rhizoplane of the terrestrial orchid was also populated by cyanobacteria of ... | 2001 | 11558285 |
| the evolution of glutathione metabolism in phototrophic microorganisms. | of the many roles ascribed to glutathione (gsh) the one most clearly established is its role in the protection of higher eucaryotes against oxygen toxicity through destruction of thiol-reactive oxygen byproducts. if this is the primary function of gsh then gsh metabolism should have evolved during or after the evolution of oxygenic photosynthesis. that many bacteria do not produce gsh is consistent with this view. in the present study we have examined the low-molecular-weight thiol compositio ... | 1987 | 11542078 |
| contrasting modes of photosynthetic enzyme regulation in oxygenic and anoxygenic prokaryotes. | enzymes that are regulated by the ferredoxin/thioredoxin system in chloroplasts--fructose-1,6-bis-phosphatase (fbpase), sedoheptulose-1,7-bisphosphatase (sbpase), and phosphoribulokinase (prk)--were partially purified from two different types of photosynthetic prokaryotes (cyanobacteria, purple sulfur bacteria) and tested for a response to thioredoxins. each of the enzymes from the cyanobacterium nostoc muscorum, an oxygenic organism known to contain the ferredoxin/thioredoxin system, was activ ... | 1984 | 11536590 |
| genetic diversity of nostoc symbionts endophytically associated with two bryophyte species. | the diversity of the endophytic nostoc symbionts of two thalloid bryophytes, the hornwort anthoceros fusiformis and the liverwort blasia pusilla, was examined using the trna(leu) (uaa) intron sequence as a marker. the results confirmed that many different nostoc strains are involved in both associations under natural conditions in the field. the level of nostoc diversity within individual bryophyte thalli varied, but single dna fragments were consistently amplified from individual symbiotic colo ... | 2001 | 11526056 |
| characterization by genotypic methods of symbiotic nostoc strains isolated from five species of gunnera. | the genetic diversity of ten symbiotic nostoc strains isolated from different gunnera species was investigated. the strains were analyzed using molecular methods with different taxonomic resolutions, including restriction fragment length polymorphisms (rflp) of the pcr-amplified 16s ribosomal gene and the 16s-23s internal transcribed spacer (its) region combined with computer-assisted analyses. the functional gene hetr, assigned to heterocyst differentiation, was used for denaturing gradient gel ... | 2001 | 11511868 |
| the role of papillae during the infection process in the gunnera-nostoc symbiosis. | gunnera manicata l. glands consist of up to nine separate papillae. surgical removal of papillae showed that more than two papillae were needed for successful infection with nostoc. infection occurs only in the enclosed space between adjacent papillae. dividing gunnera cells in the enclosed space are the sites of infection. | 2001 | 11479387 |
| cryptophycins: a novel class of potent antimitotic antitumor depsipeptides. | the antitumor cryptophycins are synthetic derivatives of the desipeptide cryptophycins isolated from the cyanobacterium nostoc sp. cryptophycin 52 that is currently in clinical trial in solid tumors, is prepared by total synthesis of four key fragments that are coupled to form the final product. the mechanism of anticancer activity of the cryptophycins has been associated with their destabilization of microtubules and with their induction of bcl-2 phosphorylation leading to apoptosis. the crypto ... | 2001 | 11472266 |
| induction of mycosporine-like amino acids (maas) in cyanobacteria by solar ultraviolet-b radiation. | three filamentous and heterocystous n(2)-fixing cyanobacteria, anabaena sp., nostoc commune and scytonema sp. were tested for the presence of ultraviolet-absorbing mycosporine-like amino acids (maas) and their induction by solar ultraviolet-b (uv-b) radiation. high performance liquid chromatographic (hplc) studies revealed the presence of only one type of maas in all three cyanobacteria, that was identified as shinorine, a bisubstituted maa containing both glycine and serine groups having an abs ... | 2001 | 11470569 |
| expression, refolding and crystallization of the opca invasin from neisseria meningitidis. | opca is an integral outer membrane from the gram-negative pathogen neisseria meningitidis that plays a role in adhesion of meningococci to host cells. the protein was overexpressed in escherichia coli in an insoluble form and a procedure developed for refolding by rapid dilution from denaturant into detergent solution. the refolded material was identical to native opca isolated from meningococci, as judged by overall molecular weight, migration on sds-page and reaction against monoclonal antibod ... | 2001 | 11468407 |
| [ultrastructure of the cell surface of heteromorphic nostoc muscorum calu 304 cocultured with rauwolfia tissue]. | the ultrastructure of the heteromorphic cells (hmcs) of the cyanobacterium nostoc muscorum calu 304 grown in pure culture, monoculture, and a mixed culture with the rauwolfia callus tissue was studied. the comparative analysis of the cell surface of hmcs, the frequency of the generation of cell forms with defective cell walls (dcwfs), including protoplasts and spheroplasts, and the peculiarities of the cell surface ultrastructure under different growth conditions showed that, in the early terms ... | 2001 | 11450455 |
| cloning and characterisation of a hyp gene cluster in the filamentous cyanobacterium nostoc sp. strain pcc 73102. | maturation of [nife]-hydrogenases requires the action of several groups of accessory genes. homologues of one group of these genes, the so-called hyp genes, putatively encoding proteins participating in the formation of an active uptake hydrogenase in the filamentous, heterocyst-forming cyanobacterium nostoc pcc 73102, were cloned. the cluster, consisting of hypf, hypc, hypd, hype, hypa, and hypb, is located 3.8 kb upstream from the uptake hydrogenase-encoding hupsl. gene expression analyses sho ... | 2001 | 11445168 |
| nostocyclamide m: a cyanobacterial cyclic peptide with allelopathic activity from nostoc 31. | a cyclic peptide containing thiazole and oxazole moieties was isolated from nostoc 31 and its structure determined by chemical degradation detailed nmr and mass spectroscopic analyses. the compound is stereochemically pure and closely related to nostocyclamide in which d-valine is replaced by d-methionine. therefore, it differs from tenuecyclamide c reported to contain l-methionine. it shows allelopathic activity against anabaena 7120, but is inactive against grazers. | 2001 | 11394868 |
| binding of ferric heme by the recombinant globin from the cyanobacterium synechocystis sp. pcc 6803. | the product of the cyanobacterium synechocystis sp. pcc 6803 gene slr2097 is a 123 amino acid polypeptide chain belonging to the truncated hemoglobin family. recombinant, ferric heme-reconstituted synechocystis sp. pcc 6803 hemoglobin is a low-spin complex whose endogenous hexacoordination gives rise to optical and nmr characteristics reminiscent of cytochrome b(5) [scott, n. l., and lecomte, j. t. j. (2000) protein sci. 9, 587-597]. in this work, the sequential assignments using (15)n-(13)c-lab ... | 2001 | 11371218 |
| [features of cyanobacterial-bacterial complexes of microsymbionts of plant syncyanoses]. | the morphology and ultrastructure of associative microsymbiont complexes (amc) isolated from the ferns azolla pinnata and azolla sp. and the apogeotropic roots of the cycad cycas revoluta were studied. the composition of the amc obtained includes the cyanobionts (symbiotic cyanobacteria) and satellite bacteria (sb). it was found that two types of cyanobacteria that substantially differ in their morphological organization are likely present as cyanobionts in the coralloids of c. revoluta. the iso ... | 2001 | 11338829 |
| prenostodione, a novel uv-absorbing metabolite from a natural bloom of the cyanobacterium nostoc species. | a novel uv-absorbing natural product, prenostodione (1), has been isolated from a natural bloom of the cyanobacterium nostoc sp. (tau strain il-235). homonuclear and heteronuclear 2d nmr techniques as well as hreims determined the gross structure of 1. | 2001 | 11325247 |
| molecular characterization of planktic cyanobacteria of anabaena, aphanizomenon, microcystis and planktothrix genera. | toxic and non-toxic cyanobacterial strains from anabaena, aphanizomenon, calothrix, cylindrospermum, nostoc, microcystis, planktothrix (oscillatoria agardhii), oscillatoria and synechococcus genera were examined by rflp of pcr-amplified 16s rrna genes and 16s rrna gene sequencing. with both methods, high 16s rrna gene similarity was found among planktic, anatoxin-a-producing anabaena and non-toxic aphanizomenon, microcystin-producing and non-toxic microcystis, and microcystin-producing and non-t ... | 2001 | 11321098 |
| fluorescent detection of cyanobacterial dna using bacterial magnetic particles on a mag-microarray. | bacterial magnetic particles (bmps) were used for the identification of cyanobacterial dna. genus-specific oligonucleotide probes for the detection of anabaena spp., microcystis spp., nostoc spp., oscillatoria spp., and synechococcus spp. were designed from the variable region of the cyanobacterial 16s rdna of 148 strains. these oligonucleotide probes were immobilized on bmps via streptavidin-biotin conjugation and employed for magnetic-capture hybridization against digoxigenin-labeled cyanobact ... | 2001 | 11320510 |
| the hetf gene product is essential to heterocyst differentiation and affects hetr function in the cyanobacterium nostoc punctiforme. | a novel gene, hetf, was identified as essential for heterocyst development in the filamentous cyanobacterium nostoc punctiforme strain atcc 29133. in the absence of combined nitrogen, hetf mutants were unable to differentiate heterocysts, whereas extra copies of hetf in trans induced the formation of clusters of heterocysts. sequences hybridizing to a hetf probe were detected only in heterocyst-forming cyanobacteria. the inactivation and multicopy effects of hetf were similar to those of hetr, w ... | 2001 | 11274126 |
| gene transfer to the desiccation-tolerant cyanobacterium chroococcidiopsis. | the coccoid cyanobacterium chroococcidiopsis dominates microbial communities in the most extreme arid hot and cold deserts. these communities withstand constraints that result from multiple cycles of drying and wetting and/or prolonged desiccation, through mechanisms which remain poorly understood. here we describe the first system for genetic manipulation of chroococcidiopsis. plasmids pduca7 and prl489, based on the pdu1 replicon of nostoc sp. strain pcc 7524, were transferred to different iso ... | 2001 | 11244070 |
| host specificity in the richelia-diatom symbiosis revealed by hetr gene sequence analysis. | the filamentous heterocyst-forming cyanobacterium richelia intracellularis forms associations with diatoms and is very abundant in tropical and subtropical seas. the genus richelia contains only one species, r. intracellularis schmidt, although it forms associations with several diatom genera and has considerable variation in size and morphology. the genetic diversity, and possible host specificity, within the genus richelia is unknown. using primers against hetr, a gene unique for filamentous c ... | 1999 | 11207763 |
| cyanovirin-n, a potent human immunodeficiency virus-inactivating protein, blocks both cd4-dependent and cd4-independent binding of soluble gp120 (sgp120) to target cells, inhibits scd4-induced binding of sgp120 to cell-associated cxcr4, and dissociates bound sgp120 from target cells. | cyanovirin-n (cv-n), an 11-kda protein originally isolated from the cyanobacterium nostoc ellipsosporum, potently inactivates diverse strains of human immunodeficiency virus type 1 (hiv-1), hiv-2, simian immunodeficiency virus, and feline immunodeficiency virus. it has been well established that the hiv surface envelope glycoprotein gp120 is a molecular target of cv-n. we recently reported that cv-n impaired the binding of virion-associated gp120 to cell-associated cd4 and that cv-n preferential ... | 2001 | 11181340 |
| effect of copper and lead on lipid metabolism in bryophytes and lichens. | bryophytes and lichens have a widespread occurrence and can survive under extreme environmental conditions, such as drought, low temperatures, continuous light or prolonged darkness. it has been shown that lipid metabolism is sensitive to both metal response and metal resistance mechanisms in many organisms, including yeast, silene cucubalus, and in the marine brown algae fucus spp. and ascophyllum nodosum. in the present study, the effects of lead and copper on lipid metabolism have been studie ... | 2000 | 11171254 |
| isolation and structure determination of nostocyclopeptides a1 and a2 from the terrestrial cyanobacterium nostoc sp. atcc53789. | the isolation and total structure determination of nostocyclopeptides a1 (1) and a2 (2) are described. these cyclic heptapeptides, which possess a unique imino linkage in the macrocyclic ring, are characteristic constituents of the cryptophycin-producing cyanobacterium nostoc sp. atcc53789. 1d tocsy experiments proved to be very useful in identifying the seven amino acid residues in each compound, and hmbc and noesy correlations made it possible to sequence the seven units into a total gross str ... | 2001 | 11170666 |
| molecular evidence for the aerobic expression of nifj, encoding pyruvate:ferredoxin oxidoreductase, in cyanobacteria. | pyruvate:ferredoxin (flavodoxin) oxidoreductase (pfo, ec 1.2.7.1) catalyses the oxidative cleavage of pyruvate and coenzyme a to acetylcoenzyme a and co2 with the simultaneous reduction of ferredoxin or flavodoxin. pfo occurs in anaerobes and in some aerobic archaea and bacteria. for cyanobacteria, activity measurements indicated the occurrence of pfo in heterocystous forms. the completely sequenced genomes of the unicellular synechocystis sp. pcc 6803 and the heterocystous anabaena sp. pcc 7120 ... | 2001 | 11167002 |
| cloning and characterization of the pkna gene from streptomyces coelicolor a3(2), coding for the mn2+ dependent protein ser/thr kinase. | a gene pkna, coding for an eukaryotic-type protein ser/thr kinase, was cloned from the streptomyces coelicolor a3(2) chromosome. the pkna protein kinase, containing the c-terminal eukaryotic-type kinase domain with an n-terminal extension, was expressed in escherichia coli and streptomyces lividans. the affinity purified mbp-pkna fusion protein was assayed for kinase activity that showed its ability to autophosphorylate in vitro in the presence of [gamma-32p]atp. the activity was mn2+ dependent. ... | 2000 | 11162454 |
| the unique cyanobacterial protein opca is an allosteric effector of glucose-6-phosphate dehydrogenase in nostoc punctiforme atcc 29133. | glucose-6-phosphate dehydrogenase (g6pd), encoded by zwf, is essential for nitrogen fixation and dark heterotrophic growth of the cyanobacterium nostoc punctiforme atcc 29133. in n. punctiforme, zwf is part of a four-gene operon transcribed in the order fbp-tal-zwf-opca. genetic analyses indicated that opca is required for g6pd activity. to define the role of opca, the synthesis, aggregation state, and activity of g6pd in n. punctiforme strains expressing different amounts of g6pd and/or opca we ... | 2001 | 11152472 |
| site-specific restriction endonucleases in cyanobacteria. | planktic cyanobacteria were screened for endodeoxyribonucleases. principal component analysis (pca) was employed to demonstrate a potential relationship between certain enzymes and a group of cyanobacteria. the data were obtained from a data bank and this study. | 2000 | 11123471 |
| a primitive myoglobin from tetrahymena pyriformis: its heme environment, autoxidizability, and genomic dna structure. | a myoglobin-like protein isolated from tetrahymena pyriformis is composed of 121 amino acid residues. this is much smaller than sperm whale myoglobin by 32 residues, suggesting a distinct origin from the common globin gene. we have therefore examined this unique protein for its structural, spectral and stability properties. as a result, the rate of autoxidation of tetrahymena oxymyoglobin (mbo(2)) was found to be almost comparable to that of sperm whale mbo(2) over a wide range of ph 4-12 in 0.1 ... | 2000 | 11087949 |
| nostocyclyne a, a novel antimicrobial cyclophane from the cyanobacterium nostoc sp. | a novel acetylene-containing para-[14]-cyclophane, nostocyclyne a (1), possessing antimicrobial activity, is the major active metabolite of the natural bloom of the cyanobacterium nostoc sp. (tau strain il-220). homonuclear and heteronuclear 2d nmr techniques as well as hreims determined the gross structure of 1. | 2000 | 11087597 |
| a cyanobacterial recombination study, involving an efficient n2-fixing non-heterocystous partner. | many filamentous cyanobacteria fix atmospheric nitrogen under natural conditions in specialized anaerobic compartments, heterocysts, interspersed between vegetative cells, which provide protection to the o2-sensitive nitrogenase. a few unicellular cyanobacterial strains are also known to fix nitrogen aerobically at a slower rate. filamentous cyanobacteria lacking heterocysts are not known so far to fix nitrogen. we describe the isolation and purification of a non-heterocystous filamentous cyanob ... | 2000 | 11061181 |
| [spatial integration of partners and heteromorphism of cyanobacterium nostoc muscoum calu 304 in mixed culture with rauwolfia]. | a comparative morphological study was conducted of nostoc muscorum calu 304 grown either as a pure culture on standard media or as a mixed culture with rauwolfia callus tissue on a medium for plant tissue cultivation. the interaction of the cyanobacterial and plant partners results in their spatial integration into aggregates of specific anatomy, which arise periodically during the mixed culture growth. the morphology of the cyanobacterial cells varies depending on their localization in the comb ... | 2000 | 11008694 |
| the use of the 2-aminobenzoic acid tag for oligosaccharide gel electrophoresis. | gel electrophoresis of fluorophore labeled saccharides provides a rapid and reliable method to screen enzymatic and/or chemical treatments of polysaccharides and glycoconjugates, as well as a sensitive and efficient microscale method to separate and purify oligosaccharides for further analysis. a simple and inexpensive method of derivatization and analysis using 2-aminobenzoic acid (anthranilic acid, aa) is described and applied to the extracellular polysaccharide released by the desiccation tol ... | 2000 | 11005578 |
| new antibacterial metabolites from the cyanobacterium nostoc commune(eawag 122b). | two new compounds, a diterpenoid and an anthraquinone, as well as an indane derivative, which is reported as a natural product for the first time, have been isolated from the cells of the cultured cyanobacterium nostoc commune (eawag 122b) by means of bioguided isolation. the structures were determined by spectroscopic methods, mainly nmr, infrared spectroscopy, and mass spectrometry. all isolates exhibit antibacterial activity. | 2000 | 11000038 |
| a cyanobacterial mutant resistant against a bleaching herbicide. | the nitrogen fixing cyanobacterium nostoc muscorum has been found to be sensitive to the herbicide san 6706 [4-chloro-5 (dimethylamino)-2-(a,a,a,-trifluoro-m-tolyl)-3-(2h) pyridazinon] at 30-45 microm within 15 min. the toxicity was more severe in combined nitrogen-free (ncomb-free) medium than in a combined nitrogen medium; this enhancement was reversible by supplementation of the medium with 3 mm glucose or 5 microm atp, serving as carbon and/or energy source in this organism. a mutant of this ... | 2000 | 10986674 |
| hups and hupl constitute a transcription unit in the cyanobacterium nostoc sp. pcc 73102. | the heterocystous cyanobacterium nostoc sp. pcc 73102 possesses an uptake hydrogenase encoded by hups and hupl. the genes are transcribed in cells grown under n2-fixing but not under non-n2-fixing conditions. we characterised the transcription of hups and hupl in further detail. a transcription start site was located at a position 259 bp upstream from the hups translation start. as shown by rt-pcr, hups and hupl constitute a single transcript in nostoc sp. pcc 73102. the possible function of sho ... | 2000 | 10985753 |
| application of sequence-specific labeled 16s rrna gene oligonucleotide probes for genetic profiling of cyanobacterial abundance and diversity by array hybridization. | dna sequence information for the small-subunit rrna gene (16s rdna) obtained from cyanobacterial cultures was used to investigate the presence of cyanobacteria and their abundance in natural habitats. eight planktonic communities developing in lakes characterized by relatively low algal biomass (mesotrophic) and in lakes with correspondingly high biomass (eutrophic) were selected for the study. the organismal compositions of the water samples were analyzed genetically, using multiplex sequence-s ... | 2000 | 10966421 |
| determinative value of a portion of the nifh sequence for the genera nostoc and anabaena (cyanobacteria). | the taxonomic positions of nostoc and anabaena strains are currently disputed. we selected three nostoc and anabaena strains, using the classic criteria of morphology and life cycle. dna sequences of a part of the nifh gene were determined from these strains and aligned with homologous sequences from 10 other nostoc/anabaena strains in the public databases. phylogenetic reconstructions were carried out to test the consistency of the taxonomic placement of these strains. the phylogenetic trees do ... | 2000 | 10915207 |
| the mycobacterium bovis homologous protein of the mycobacterium tuberculosis serine/threonine protein kinase mbk (pknd) is truncated. | we previously identified a 70-kda serine/threonine protein kinase (mbk or pknd) from mycobacterium tuberculosis erdman containing a transmembrane domain and bearing a 270-amino acid n-terminal kinase domain. with the use of a polyclonal serum, mbk has now been identified by western blotting in protein extracts from m. tuberculosis and confirmed to be localised in the envelope. an identical mbk gene has been found by sequencing different m. tuberculosis and m. africanum strains. surprisingly, in ... | 2000 | 10913696 |
| flavonoid-induced expression of a symbiosis-related gene in the cyanobacterium nostoc punctiforme. | the flavonoid naringin was found to induce the expression of hrma, a gene with a symbiotic phenotype in the cyanobacterium nostoc punctiforme. a comparative analysis of several flavonoids revealed the 7-o-neohesperidoside, 4'-oh, and c-2-c-3 double bond in naringin as structural determinants of its hrma-inducing activity. | 2000 | 10913102 |
| structural investigations of the hemoglobin of the cyanobacterium synechocystis pcc6803 reveal a unique distal heme pocket. | a putative hemoglobin (hb) gene, related to those previously characterized in the green alga chlamydomonas eugametos, the ciliated protozoan paramecium caudatum, the cyanobacterium nostoc commune and the bacterium mycobacterium tuberculosis, was recently discovered in the complete genome sequence of the cyanobacterium synechocystis pcc 6803. in this paper, we report the purification of synechocystis hb and describe some of its salient biochemical and spectroscopic properties. we show that the re ... | 2000 | 10903511 |
| intracellular accommodation of microbes by plants: a common developmental program for symbiosis and disease? | plant cells engage in mutualistic and parasitic endosymbioses with a wide variety of microorganisms, ranging from gram-negative (rhizobium, nostoc) and gram-positive bacteria (frankia), to oomycetes (phytophthora), chytridiomycetes, zygomycetes (arbuscular mycorrhizal fungi) and true fungi (erysiphe, ascomycete; puccinia, basidiomycete). endosymbiosis is characterised by the 'symbiosome', a compartment within host cells in which the symbiotic microorganism is either partially or completely enclo ... | 2000 | 10873847 |
| dual effects of pknalpha and protein kinase c on phosphorylation of tau protein by glycogen synthase kinase-3beta. | we analyzed the effects of pknalpha and protein kinase c (pkc) on phosphorylation of tau protein by glycogen synthase kinase (gsk)-3beta using monoclonal antibodies (at8, at180, and at270). these antibodies are highly specific for phosphorylated tau in alzheimer paired helical filaments, and recognize phosphorylated ser202/thr205, thr231, and thr181 of tau protein, respectively. immunoblot analysis demonstrated that pknalpha and pkc did not directly phosphorylate their sites, whereas gsk-3beta e ... | 2000 | 10873588 |
| cyanobacteria as a biosorbent of heavy metals in sewage water. | the effect of sewage water on some physiological activities of cyanobacteria was studied. metal-tolerant cyanobacterium (nostoc linckia) and metal-sensitive (nostoc rivularis) were grown at three levels of sewage water (25, 50 and 75%). the growth rate showed significant stimulation in low and moderate levels (50% for n. linckia and 25% for n. rivularis). not only the number of cells was elevated but also, the time required to reach the exponential and the stationary phases was reduced. also, lo ... | 2000 | 10867368 |
| toxin production in cyanobacterial mats from ponds on the mcmurdo ice shelf, antarctica. | cyanobacteria are known to produce hepatotoxic substances, the functional and ecological role of these toxins, however, remains largely unclear. toxic properties of cyanobacteria collected in antarctica were investigated to determine whether toxin-producing species can also be found under these environmental conditions. samples were collected from meltwater ponds on the mcmurdo ice shelf, antarctica in the summers of 1997 to 1999. these ponds are colonized by benthic algae and cyanobacterial mat ... | 2000 | 10858513 |
| characterization of devh, a gene encoding a putative dna binding protein required for heterocyst function in anabaena sp. strain pcc 7120. | the devh gene was identified in a screen for anabaena sp. strain pcc 7120 sequences whose transcripts increase in abundance during a heterocyst development time course. the product of devh contains a helix-turn-helix motif similar to the dna binding domain of members of the cyclic amp receptor protein family, and the protein is most closely related to the cyanobacterial transcriptional activator ntca. devh transcripts are barely detectable in vegetative cells and are induced approximately fivefo ... | 2000 | 10852891 |
| comparison of conserved structural and regulatory domains within divergent 16s rrna-23s rrna spacer sequences of cyanobacteria. | pcr amplification of the internal transcribed spacer (its) between the 16s rrna and 23s rrna genes of the cyanobacterium nostoc: pcc 7120 gave three products. two represented true its regions of different sizes, while the third was a heteroduplex. the longer spacer (its-l) contained 512 nucleotides and carried trna(ile) and trna(ala) genes, separated by a large stem-loop structure (v2) composed of short tandemly repeated repetitive sequences. both trna genes, and the 5' half of the intervening s ... | 2000 | 10846207 |
| a convergent synthesis of (+)-cryptophycin b, a potent antitumor macrolide from nostoc sp. cyanobacteria. | [structure--see text] an efficient and highly stereoselective synthesis of cryptophycin b (2), a potent cytotoxic agent, is described. the ester-derived titanium-enolate-mediated syn-aldol reaction was employed to generate the stereocenters c(5) and c(6). the route is convergent and provides a convenient access to the synthesis of structural variants of cryptophycin b as well as members of its family. | 2000 | 10841482 |
| cyanobacterial diversity in geographically related and distant host plants of the genus gunnera. | the diversity among 45 cyanobacterial isolates from 11 different gunnera species originating from different geographical areas was examined. by means of polymerase chain reaction (pcr) fingerprinting with short tandemly repeated repetitive (strr) sequences as primers, ten groups of symbiotic cyanobacteria and five unique isolates not belonging to a particular group were identified. most groups were restricted to one geographical area, indicating a limited distribution of related cyanobacterial s ... | 2000 | 10795680 |
| properties of cyanovirin-n (cv-n): inactivation of hiv-1 by sessile cyanovirin-n (scv-n). | cyanovirin-n (cv-n) is a novel anti-hiv protein isolated and characterized from a cyanobacterium nostoc ellipsosporum. cv-n protein is a single 101 amino acid chain containing two intrachain disulphide bonds and considerable internal sequence duplication, but no significant homology to previously described proteins or to the transcription products of known nucleotide sequences. in solution, cv-n exists largely as a beta-sheet protein with internal two-fold pseudosymmetry. cv-n irreversibly inact ... | 2000 | 10794101 |
| n-(cyclohexanecarboxyl)-o-phospho-l-serine, a minimal substrate for the dual-specificity protein phosphatase iphp. | three dual-specific phosphatases [dsps], iphp, vhr, and cdc14, and three protein-tyrosine phosphatases [ptps], ptp-1b, ptp-h1, and tc-ptpa, were challenged with a set of low molecular weight phosphoesters to probe the factors underlying the distinct substrate specificities displayed by these two mechanistically homologous families of protein phosphatases. it was observed that beta-naphthyl phosphate represented an excellent general substrate for both ptps and dsps. while dsps tended to hydrolyze ... | 2000 | 10775432 |
| inhibition of croton oil-induced oedema in mice ear skin by capsular polysaccharides from cyanobacteria. | the anti-inflammatory properties of hydrophilic extracts of the capsular polymers of twelve cyanobacterial strains belonging to the genera phormidium and nostoc from marine and terrestrial habitats were tested topically on croton oil-induced oedema in mice ear skin. the screening program identified several strains as producers of anti-inflammatory products (up to 56% inhibition of the oedema). the inhibition response was dose-dependent. the application of trichloroacetic acid-treated extracts re ... | 2000 | 10763863 |
| novel extracellular diterpenoids with biological activity from the cyanobacterium nostoc commune. | five novel extracellular metabolites with an unprecedented diterpenoid skeleton, 5-[(5-carboxy-2-hydroxy)benzyl]-11-hydroxymethyl-2,5,6,8a, 11-pentamethyldodecahydrocyclopenta<a>naphthalene (1), 5-[(5-carboxy-2-hydroxy)benzyl]-11-formyl-2,5,6,8a, 11-pentamethyl-dodecahydrocyclopenta<a>naphthalene (2), 5-[(5-carboxy-2-hydroxy)benzyl]-11-carboxy-2,5,6,8a, 11-pentamethyl-dodecahydrocyclopenta<a>naphthalene (3), 5-[(5-carboxy-2-hydroxy)benzyl]-11-dihydroxymethyl-2,5,6,8a, 11-pentamethyldodecahydrocy ... | 2000 | 10757714 |
| solution 1h nmr study of the heme cavity and folding topology of the abbreviated chain 118-residue globin from the cyanobacterium nostoc commune. | the globin from the cyanobacterium nostoc commune, abbreviated glbn, which appears to serve as a part of a terminal oxidase rather than as a respiratory pigment, displays relatively normal o2 binding properties, despite the highly abbreviated polypeptide chain, (118 residues) relative to more conventional globins [thorsteinsson, m. v. , bevan, d. r., potts, m., dou, y., eich, r. f., hargrove, m. s., gibson, q. h., and olson, j. s. (1999) biochemistry 38, 2117-2126]. the nature of the heme cavity ... | 2000 | 10684619 |
| structural characterization of the released polysaccharide of desiccation-tolerant nostoc commune drh-1. | the structure of the viscous extracellular polysaccharide (glycan) of desiccation-tolerant nostoc commune drh-1 was determined through chromatographic and spectroscopic methods. the polysaccharide is novel in that it possesses a 1-4-linked xylogalactoglucan backbone with d-ribofuranose and 3-o-[(r)-1-carboxyethyl]-d-glucuronic acid (nosturonic acid) pendant groups. the presence of d-ribose and nosturonic acid as peripheral groups is unusual, and their potential roles in modulating the rheologica ... | 2000 | 10648523 |
| active fe-containing superoxide dismutase and abundant sodf mrna in nostoc commune (cyanobacteria) after years of desiccation. | active fe-superoxide dismutase (sodf) was the third most abundant soluble protein in cells of nostoc commune chen/1986 after prolonged (13 years) storage in the desiccated state. upon rehydration, fe-containing superoxide disumutase (fe-sod) was released and the activity was distributed between rehydrating cells and the extracellular fluid. the 21-kda fe-sod polypeptide was purified, the n terminus was sequenced, and the data were used to isolate sodf from the clonal isolate n. commune drh1. sod ... | 2000 | 10613879 |
| separation and identification of hydrocarbons and other volatile compounds from cultured blue-green alga nostoc sp. by gas chromatography-mass spectrometry using serially coupled capillary columns with consecutive nonpolar and semipolar stationary phases. | the complex hydrocarbons and volatile compounds produced by cultured blue-green alga nostoc sp. were separated by serially coupled capillary columns with consecutive nonpolar and semipolar stationary phases. more than 130 metabolites including, cyclohexane, cyclopentane, normal saturated hydrocarbons (c7-c30), fatty acids and benzene derivatives were identified by gc-ms. the most abundant family of hydrocarbons identified were derivatives of cyclohexane (41) and cyclopentane (11). most of these ... | 1999 | 10596980 |
| the solution structure of photosystem i accessory protein e from the cyanobacterium nostoc sp. strain pcc 8009. | psae is a small basic subunit located on the stromal (cytoplasmic) side of photosystem i. in cyanobacteria, this subunit participates in cyclic electron transport and modulates the interactions of the complex with soluble ferredoxin. the psae protein isolated from the cyanobacterium synechococcus sp. strain pcc 7002 adopts the beta topology of an sh3 domain, with five beta strands (betaa through betae) and a turn of 3(10) helix between strands betad and betae [falzone, c. j., kao, y.-h., zhao, j ... | 1999 | 10521281 |
| energy-dependent ca(2+) efflux from the cells of nostoc calcicola breb: role of modifying factors | energy-dependent ca(2+) efflux and its regulation from the diazotrophic cyanobacterium nostoc calcicola breb has been investigated. like ca(2+) uptake, ca(2+) efflux pattern also reflected a rapid phase for the first 10 min followed by a slower one lasting up to 1 h with a total of 80 nmol ca(2+) mg(-1) protein (31% of the ca(2+) concentration taken in by such cells at 1 h). ca(2+) efflux kinetics remained hyperbolic with a k(m) of 1.9 mm and v(max) 5.5 nmol mg(-1) protein min(-1). ca(2+) efflux ... | 1999 | 10489433 |
| biochemical and genetic evidence for participation of devr in a phosphorelay signal transduction pathway essential for heterocyst maturation in nostoc punctiforme atcc 29133. | in a test of the hypothesis that devr is a response regulator protein that functions in a phosphorelay signal transduction system involved in heterocyst development in nostoc punctiforme atcc 29133, purified affinity-tagged devr was shown to be phosphorylated in vitro by the noncognate sensor kinase envz. site-directed mutagenesis was used to generate n. punctiforme mutants with single amino acid substitutions at the putative phosphorylation site of devr. these mutants exhibited a fox- phenotype ... | 1999 | 10400605 |
| extended heme promiscuity in the cyanobacterial cytochrome c oxidase: characterization of native complexes containing hemes a, o, and d, respectively. | the cyanobacteria anacystis nidulans (synechococcus sp. pcc6301), synechocystis sp. pcc6803, anabaena sp. pcc 7120, and nostoc sp. pcc8009 were grown photoautotrophically under reduced oxygen tension in a medium with sulfate replaced by thiosulfate and nitrate replaced by ammonium as the s- and n-sources, respectively. in addition, anabaena and nostoc were grown under dinitrogen-fixing conditions in a medium free of combined nitrogen. membranes were isolated from late-logarithmic cells (culture ... | 1999 | 10375407 |
| cyanovirin-n binds to gp120 to interfere with cd4-dependent human immunodeficiency virus type 1 virion binding, fusion, and infectivity but does not affect the cd4 binding site on gp120 or soluble cd4-induced conformational changes in gp120. | cyanovirin-n (cv-n), an 11-kda protein isolated from the cyanobacterium nostoc ellipsosporum, potently inactivates diverse strains of human immunodeficiency virus type 1 (hiv-1), hiv-2, and simian immunodeficiency virus. while it has been well established that the viral surface envelope glycoprotein gp120 is a molecular target of cv-n, the detailed mechanism of action is of further interest. we compared matched native and cv-n-treated virus preparations in a panel of assays that measure viral re ... | 1999 | 10196334 |
| a novel extracellular diterpenoid with antibacterial activity from the cyanobacterium nostoc commune. | a novel extracellular metabolite with an unprecedented diterpenoid skeleton, 8-[(5-carboxy-2-hydroxy)benzyl]-2-hydroxy-1,1,4a,7, 8-pentamethyl-1,2,3,4,4a,6,7,8,8a,9,10,10a-dodecahydrophenanthrene , has been isolated from the culture medium of the terrestrial cyanobacterium nostoc commune vaucher (eawag 122b) by means of bioguided isolation. the molecule was designated as noscomin. the structure was determined by spectroscopic methods, mainly nmr and mass spectrometry. noscomin exhibited antibact ... | 1999 | 10096870 |
| the frua signal transduction protein provides a checkpoint for the temporal co-ordination of intercellular signals in myxococcus xanthus development. | during fruiting body morphogenesis in myxococcus xanthus, the intercellular c-signal induces aggregation, sporulation and developmental gene expression. to understand how a single signal system may induce temporally separated processes, we have focused on the class ii gene, which codes for an essential component in the c-signal transduction pathway. we report that class ii is identical to frua and codes for a dna binding response regulator. transcription of frua is developmentally regulated and ... | 1998 | 10094629 |
| a cyanobacterial hemoglobin with unusual ligand binding kinetics and stability properties. | the glbn gene of the cyanobacterium nostoc commune utex 584 encodes a hemoprotein, named cyanoglobin, that has high oxygen affinity. the basis for the high oxygen affinity of cyanoglobin was investigated through kinetic studies that utilized stopped-flow spectrophotometry and flash photolysis. association and dissociation rate constants were measured at 20 degrees c for oxygen, carbon monoxide, nitric oxide, and methyl and ethyl isocyanides. the association rate constants for the binding of thes ... | 1999 | 10026295 |
| transcriptional regulation of nostoc uptake hydrogenase. | filamentous, heterocystous cyanobacteria may contain both an uptake hydrogenase (encoded by hupsl) and a bidirectional enzyme (encoded by hoxfuyh). the present study identifies three strains (anabaena variabilis, nostoc muscorum and nostoc sp. strain pcc 73102) with a contiguous hupl in both vegetative cells and heterocysts. the two nostoc strains differ in either containing a bidirectional enzyme (n. muscorum) or lacking this enzyme (n. pcc 73102). transcriptional studies, using reverse transcr ... | 1999 | 9919654 |
| safety evaluation of nostoc flagelliforme (nostocales, cyanophyceae) as a potential food. | the safety of the alga genus nostoc flagelliforme born. etflah. as a human food source was evaluated in an oral acute toxicity study and in a 28-day oral subacute toxicity study using rats. in the acute toxicity study, the dried powder of n. flagelliforme was orally administered to male and female rats at a dose of 1250 mg/kg and 2500 mg/kg. neither mortality nor changes in general condition were observed in either the study groups or the control group over a 14-day observation period. in the su ... | 1998 | 9862649 |
| a pcr technique based on the hip1 interspersed repetitive sequence distinguishes cyanobacterial species and strains. | the use of primers based on the hip1 sequence as a typing technique for cyanobacteria has been investigated. the discovery of short repetitive sequence structures in bacterial dna during the last decade has led to the development of pcr-based methods for typing, i.e., distinguishing and identifying, bacterial species and strains. an octameric palindromic sequence known as hip1 has been shown to be present in the chromosomal dna of many species of cyanobacteria as a highly repetitious intersperse ... | 1998 | 9802020 |
| differential behaviour of two cyanobacterium species to uv radiation. artificial uv radiation induces phycoerythrin synthesis. | altitude is an important factor contributing to the local uv-b climate. in the european alps solar uv-b increases approximately 21% 1000 m-1. a nostoc muscorum (utex 389) originating from scotland and a nostoc sp. isolated from a highland lake (yanaqocha) located 3980 m above sea level (cusco, perú) have been used in a study where the tolerance to uv radiation (uvr) stress of both species was determined. following irradiation doses of 15 kj uv (uv-a plus uv-b, equivalent to approximately 6 h exp ... | 1998 | 9800379 |
| tenuecyclamides a-d, cyclic hexapeptides from the cyanobacterium nostoc spongiaeforme var. tenue. | four modified cyclic hexapeptides, tenuecyclamides a-d (1-4), were isolated along with the known antibiotic, borophycin (5), from the methanol extract of nostoc spongiaeforme var. tenue (tau strain il-184-6). the planar structure of tenuecyclamides a-d (1-4) was determined by homonuclear and inverse-heteronuclear 2d-nmr techniques as well as by high-resolution mass spectrometry measurements. the absolute configuration of the asymmetric centers was studied by marfey's method for hplc. the stereoc ... | 1998 | 9784161 |
| a simple procedure for purifying the major chloroplast fructose-1,6-bisphosphatase from spinach (spinacia oleracea) and characterization of its stimulation by sub-femtomolar mercuric ions. | a rapid procedure for the purification of the redox-regulated chloroplast fructose-1,6-bisphosphatase [ec 3.1.3.11] from spinach leaf extract to homogeneity is described. no thiol-reducing agents were present during the purification and the enzyme is > 99% in the oxidized form. a rapid procedure to reduce and activate the fru-1,6-p2ase by dithiothreitol in the absence of thioredoxin is described. reduction activates the enzyme up to several hundred-fold when assayed at ph 8.0 with 2 mm mg2+. the ... | 1998 | 9735161 |
| mutation of an alternative sigma factor in the cyanobacterium nostoc punctiforme results in increased infection of its symbiotic plant partner, anthoceros punctatus. | an alternative group 2 sigma factor was identified in the nitrogen-fixing, symbiotically competent cyanobacterium nostoc punctiforme and designated sigh. transcription of sigh was specifically induced within 1.5 h following exposure of n. punctiforme to its symbiotic plant partner, anthoceros punctatus. a mutation in sigh resulted in a sixfold-higher initial infection of a. punctatus tissue without a parallel increase in nitrogen-fixing activity. | 1998 | 9733698 |
| partial purification and characterization of ornithine carbamoyl transferase (oct) from the cyanobacterium nostoc sp. strain pcc 73102 | ornithine carbamoyl transferase (oct) catalyzes the formation of citrulline and orthophosphate from ornithine and carbamoyl phosphate. we have partially purified oct from the filamentous cyanobacterium nostoc sp. strain pcc 73102, using ammonium sulfate precipitation (35-55%), a gel-filtration column (sephacryl s-200), followed by an affinity column (sepharose-6b-palo). the partially purified oct was analyzed on native-page and shown to be an active enzyme with an estimated molecular weight of a ... | 1998 | 9732532 |
| cellular uptake of a novel cytotoxic agent, cryptophycin-52, by human thp-1 leukemia cells and h-125 lung tumor cells. | cryptophycin (cp) is a newly developed anticancer agent isolated from the terrestrial cyanobacteria of the genus nostoc. cp is a mitotic inhibitor, causing cells to accumulate in mitosis with the disappearance of intracellular microtubules. in this report, we studied the interaction and uptake of a new synthetic cp analog, cp-52, with 2 human tumor cell lines, thp-1 and h-125. in vitro colony-forming assay showed that cp-52 has antiproliferative activity against thp-1 and h-125 cell lines with i ... | 1998 | 9714056 |
| a transposition-induced mutant of nostoc ellipsosporum implicates an arginine-biosynthetic gene in the formation of cyanophycin granules and of functional heterocysts and akinetes. | in strain ne1 of tn5-1058-mutagenized nostoc ellipsosporum, the transposon was found within a gene whose translation product is similar in amino acid sequence to the arginine-biosynthetic protein n-acetylglutamate semialdehyde dehydrogenase encoded by argc of bacillus subtilis. the argc reported from anabaena sp. strain pcc 7120 hybridized to a sequence different from the one interrupted by the transposon in ne1. the newly identified gene from n. ellipsosporum was denoted argl. the argl mutation ... | 1998 | 9695912 |
| structure and properties in solution of psad, an extrinsic polypeptide of photosystem i. | psad is a small, extrinsic polypeptide located on the stromal side (cytoplasmic side in cyanobacteria) of the photosystem i reaction centre complex. the gene from the cyanobacterium nostoc sp. pcc 8009 was expressed in escherichia coli and the structure of the recovered protein in solution investigated. size-exclusion chromatography, dynamic light scattering and measurement of 15n transverse relaxation times showed that the protein is a stable dimer in solution, whereas in the reaction centre co ... | 1998 | 9692933 |
| binding of the epoxide cryptophycin analog, ly355703 to albumin and its effect on in vitro antiproliferative activity. | cryptophycin, isolated from the cyanobacterium nostoc, is a cytotoxic dioxadiazacyclohexadecenetetrone which causes rapid depletion of microtubules in intact cells. in the present report, the effect of protein binding of a new synthetic cryptophycin analog, ly355703 (cryptophycin 52), is discussed. in handling the compound, it was found to bind extensively to surfaces, and a high degree of plasma protein binding was also observed (about 99% in human plasma). similarly, while ly355703 displays po ... | 1998 | 9683814 |
| evolution of cyanobacteria by exchange of genetic material among phyletically related strains. | the cyanobacterial radiation consists of several lineages of phyletically (morphologically and genetically) related organisms. several of these organisms show a striking resemblance to fossil counterparts. to investigate the molecular mechanisms responsible for stabilizing or homogenizing cyanobacterial characters, we compared the evolutionary rates and phylogenetic origins of the small-subunit rrna-encoding dna (16s rdna), the conserved gene rbcl (encoding d-ribulose 1,5-bisphosphate carboxylas ... | 1998 | 9642201 |
| multiple oligomeric forms of glucose-6-phosphate dehydrogenase in cyanobacteria and the role of opca in the assembly process. | multiple molecular forms of glucose-6-phosphate dehydrogenase (g6pdh) were detected by activity staining in non-denaturing polyacrylamide gels of cell-free extracts from a range of cyanobacteria including anabaena sp. pcc 7120, synechococcus sp. pcc 7942, plectonema boryanum pcc 73110, synechocystis sp. pcc 6803, nostoc sp. mac pcc 8009 and the marine strain synechococcus sp. wh7803. in most of the species tested, the profile of g6pdh activities was modulated by the growth of the cells in the pr ... | 1998 | 9639925 |
| characterization of the glnb gene product of nostoc punctiforme strain atcc 29133: glnb or the pii protein may be essential. | bacterial pii proteins, encoded by glnb genes, are central signalling molecules in nitrogen regulatory pathways and are modulated by post-translational modification in response to the cellular nitrogen status. the glnb gene was cloned from the filamentous heterocyst-forming cyanobacterium nostoc punctiforme strain atcc 29133 (pcc 73102) by heterologous hybridization to a synechococcus sp. strain pcc 7942 gene fragment. expression of the cloned gene was verified by hybridization to n. punctiforme ... | 1998 | 9639924 |
| cloning and characterisation of the pknd gene encoding an eukaryotic-type protein kinase in the cyanobacterium anabaena sp. pcc7120. | protein phosphorylation catalysed by protein kinases is an important mechanism for signal transduction in both prokaryotes and eukaryotes. a novel gene, pknd, encoding a protein similar to eukaryotic-type protein kinases, was cloned from anabaena sp. pcc7120. the n-terminal region of pknd is 60% identical to that of pkna, another putative ser/thr kinase from the same strain. both pkna and pknd have c-terminal regions that are rich in pro and thr residues. expression of pknd was undetectable by r ... | 1998 | 9613569 |
| characterization of host-range mutants of cyanophage n-1. | fifteen host-range (h) mutants of cyanophage n-1 were characterized with reference to their efficiency of plating, time of appearance, morphology and size of plaques on nostoc muscorum and its three phage-resistant (nm 1/n-1, nm 2/n-1 and nm 8/n-1) mutants. while phage n-1 did not adsorb to the three phage-resistant mutants, the h mutants differed one from the other in having lower or higher adsorption rate constants on n. muscorum or the phage-resistant mutants. the inability of majority of h m ... | 1997 | 9607077 |
| electrophoretic applications of phycobiliproteins. | phycobiliproteins are homologous chromoproteins which constitute the phycobilisomes, the light harvesting complexes of the photosynthetic apparatus in cyanobacteria, rhodophyta and cryptophyta. in the present work, phycocyanin (pc) and phycoerythrin (pe) from a nostoc species are proposed as protein markers for electrophoretic techniques. phycocyanin is a blue-colored phycobiliprotein; it carries phycocyanobilin as chromophoric group and is composed of two subunits, alpha and beta, with mr of 14 ... | 1998 | 9548282 |
| hydrogen uptake in nostoc sp. strain pcc 73102. cloning and characterization of a hupsl homologue. | structural genes encoding an uptake hydrogenase of nostoc sp. strain pcc 73102 were isolated. from partial libraries of genomic dna, two clones (pnfo01 and pnfo02) were selected and sequenced, revealing the complete sequence of both a hups (960 bases) and a hupl (1,593 bases) homologue in nostoc sp. strain pcc 73102. a comparison between the deduced amino acid sequences of hups and hupl of nostoc sp. strain pcc 73102 and anabaena sp. strain pcc 7120 showed that the hups proteins are 89% identica ... | 1998 | 9531626 |
| [the destruction of microscopic organisms by their irradiation with a special form of uhf electromagnetic signals]. | electromagnetic signals of special form produced by an ultra-high frequency generator were used to destroy various microorganisms: baker's yeast; blue-green alga nostoc muscorum; mold fungus; and two flagellates, plant flagellate euglena gracilis and an animal flagellate parasitizing on humans. the control samples before irradiation and experimental samples damaged and destroyed by irradiation were examined on a microscope with a computer system of image analysis. the results are presented as co ... | 1997 | 9518060 |
| uvb-induced reduction in biomass and overall productivity of cyanobacteria. | effect of middle wave ultraviolet radiation (uvb) was studied in three different species of cyanobacteria (nostoc, anabaena and scytonema) by estimating their growth pattern, biomass yield, chlorophyll content, total starch and protein content. the results show that exposure of the cyanobacteria with uvb dose corresponding to an increase or decrease of 20% in its environmental flux will have drastic effects on biomass production, photosynthetic rate and nitrogen fixation. cyanobacteria are prima ... | 1998 | 9514891 |
| a comparison of physical properties, oxalate-oxalic acid soluble substances, protein content, and in vitro protein digestibility of the blue-green alga nostoc commune vauch. from the philippines and japan. | the physical properties, amount of oxalate-oxalic acid soluble substances (ooss), protein and in vitro protein digestibility of nostoc commune from the philippines and japan were determined. the samples were the spherical type from the philippines (ps), the dry field discoid type from the philippines (pd), and the dry field discoid type from japan (jd). the discoid types, pd and jd, regardless of origin showed higher settling volume in water (sv) and bulk density than ps. the ooss values obtaine ... | 1997 | 9477423 |
| glutamine synthetase from n2-fixing cyanobacterium nostoc muscorum--purification, biochemical and immunological characteristics. | a modified procedure for purification of glutamine synthetase [l-glutamate: ammonia ligase (adp-forming)] from n2-fixing cyanobacterium n. muscorum, to homogeneity is described using deae-sephadex and blue-sepharose affinity chromatography. specific activities of the purified enzyme in biosynthetic and transferase assays were 8.5 and 28 mumole product formed min-1 mg-1 protein. apparent molecular mass of native gs enzyme was about 610 kda as estimated by gel filtration. on sds-page the enzyme pr ... | 1997 | 9475046 |
| sequence variation of the trna(leu) intron as a marker for genetic diversity and specificity of symbiotic cyanobacteria in some lichens. | we examined the genetic diversity of nostoc symbionts in some lichens by using the trna(leu) (uaa) intron as a genetic marker. the nucleotide sequence was analyzed in the context of the secondary structure of the transcribed intron. cyanobacterial trna(leu) (uaa) introns were specifically amplified from freshly collected lichen samples without previous dna extraction. the lichen species used in the present study were nephroma arcticum, peltigera aphthosa, p. membranacea, and p. canina. introns w ... | 1998 | 9435083 |
| characterization of cyanobacteria by sds-page of whole-cell proteins and pcr/rflp of the 16s rrna gene. | planktonic, filamentous cyanobacterial strains from different genera, both toxic and nontoxic strains, were characterized by sds-page of whole-cell proteins and pcr/rflp of the 16s rrna gene. total protein pattern analysis revealed the mutual relationships at the genus level. restriction fragment length polymorphism (rflp) of the 16s rrna gene with reference strains proved to be a good method for the cyanobacterial taxonomy. the nonheterocystous strains outgrouped from the nitrogen-fixing ones. ... | 1997 | 9382701 |
| isolation, primary sequence determination, and disulfide bond structure of cyanovirin-n, an anti-hiv (human immunodeficiency virus) protein from the cyanobacterium nostoc ellipsosporum. | a novel anti-hiv protein, cyanovirin-n (cv-n), was isolated from an aqueous cellular extract of the cultured cyanobacterium (blue-green alga) nostoc ellipsosporum, purified by reverse-phase hplc, and sequenced by n-terminal edman degradation of the intact protein and peptide fragments produced by endoproteinase digestions. cv-n consists of a single 101 amino acid chain which exhibits significant internal sequence duplication, but no significant homology to previously described proteins or to the ... | 1997 | 9299483 |
| ornithine cycle in nostoc pcc 73102: presence of an in vitro functional argininosuccinate lyase. | the presence of argininosuccinate lyase (asl), an enzyme catalyzing the final step of arginine biosynthesis, was demonstrated in the heterocystous cyanobacterium nostoc pcc 73102 by measuring in vitro enzyme activity and by visualization of asl in native protein gels. activity staining of a native page gel revealed one asl-dependent band with a molecular mass of about 240 kda. a colorimetric assay for asl based on the measurement of urea produced from arginine in the presence of an excess of arg ... | 1997 | 9228773 |
| rrna sequences and evolutionary relationships among toxic and nontoxic cyanobacteria of the genus microcystis. | a primary-structure analysis of the 16s rrna gene was performed with 10 strains representing five described and one unidentified species of the genus microcystis. the phylogenies determined illustrate the evolutionary affiliations among microcystis strains, other cyanobacteria, and related plastids and bacteria. a cluster of 10 strains that included hepatotoxic isolates identified as microcystis aeruginosa formed a monophyletic group. however, the genus microcystis appeared to be polyphyletic an ... | 1997 | 9226902 |
| strain characterization and classification of oxyphotobacteria in clone cultures on the basis of 16s rrna sequences from the variable regions v6, v7, and v8. | a major problem in development of a polyphasic taxonomy is that the identification of oxyphotobacterial strains (cyanobacteria and prochlorophytes) in culture collections may be incorrect. we have therefore developed a diagnostic system using the dna sequence polymorphism in the 16s rrna regions v6 to v8 for individual strain characterization and identification. pcr primers amplifying v6 to v8 from oxyphotobacteria in unialgal cultures were constructed. direct solid-phase or cyclic sequencing wa ... | 1997 | 9212409 |