| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| a family of putative kir potassium channels in prokaryotes. | prior to this report, members of the inward rectifier family, or kir, have been found only in eukaryotes. like most k+ channels, the pore-forming part of the protein is formed by four identical, or closely related, subunits. each subunit contains a transmembrane m1-p-m2 motif that is followed by a relatively large c-terminus region unique to kir's. | 2001 | 11806753 |
| molecular characteristics of glna linked mutations in the nitrogen-fixing cyanobacterium nostoc muscorum. | the glutamine synthetase (gs)-impaired mutants of nostoc muscorum, isolated as ethylenediamine (eda) resistant phenotype, were characterized for glna linked processes to investigate the molecular mechanism of gs impairment. the gs enzyme was purified to homogeneity from the wild and mutant strains of n. muscorum employing ion-exchange followed by affinity chromatography. the final yield and specific activity of the enzyme were low in the mutant strains as compared to the wild type. the molecular ... | 2002 | 11815852 |
| immobilization results in sustained calcium transport in nostoc calcicola bréb. | the uptake pattern of ca2+ by the cyanobacterium nostoc calcicola bréb in its freely suspended and immobilized form is comprised of two distinct phages; (a) rapid uptake for 1st 10 min followed by (b) slower transport at least up to 60 min. entrapment of cyanobacterial cells in polyvinyl foam always maintained a higher ca2+ profile over freely suspended cells. also, the intracellular ca2+ concentration was three times more in the former under similar experimental conditions. whereas, illuminatio ... | 2002 | 11821924 |
| mycobacterium smegmatis and tuberculosis. | | 2002 | 11827806 |
| classification of the caspase-hemoglobinase fold: detection of new families and implications for the origin of the eukaryotic separins. | a comprehensive sequence and structural comparative analysis of the caspase-hemoglobinase protein fold resulted in the delineation of the minimal structural core of the protease domain and the identification of numerous, previously undetected members, including a new protease family typified by the hetf protein from the cyanobacterium nostoc. the first bacterial homologs of legumains and hemoglobinases were also identified. most proteins containing this fold are known or predicted to be active p ... | 2002 | 11835511 |
| long-term microclimatic stress causes rapid adaptive radiation of kaiabc clock gene family in a cyanobacterium, nostoc linckia, from "evolution canyons" i and ii, israel. | cyanobacteria are the only prokaryotes known thus far possessing regulation of physiological functions with approximate daily periodicity, or circadian rhythms, that are controlled by a cluster of three genes, kaia, kaib, and kaic. here we demonstrate considerably higher genetic polymorphism and extremely rapid evolution of the kaiabc gene family in a filamentous cyanobacterium, nostoc linckia, permanently exposed to the acute natural environmental stress in the two microsite evolutionary models ... | 2002 | 11842226 |
| the cryptophycins: their synthesis and anticancer activity. | the cryptophycins are a unique family of 16-membered macrolide antimitotic agents isolated from the cyanobacteria nostoc sp. their molecular target is tubulin protein wherein they are the most potent known stabilizers of microtubule dynamics and depolymerize microtubules at higher concentrations. they also deactivate the bcl2 protein and produce apoptotic response much more quickly and at considerably lower concentrations than clinically utilized compounds. the presence of several amide and este ... | 2002 | 11857635 |
| recovery of photosynthetic systems during rewetting is quite rapid in a terrestrial cyanobacterium, nostoc commune. | recovery processes of photosynthetic systems during rewetting were studied in detail in a terrestrial, highly drought-tolerant cyanobacterium, nostoc commune. with absorption of water, the weight of n. commune colony increased in three phases with half-increase times of about 1 min, 2 h and 9 h. fluorescence intensities of phycobiliproteins and photosystem (ps) i complexes were recovered almost completely within 1 min, suggesting that their functional forms were restored very quickly. energy tra ... | 2002 | 11867696 |
| the devt protein stimulates synthesis of frua, a signal transduction protein required for fruiting body morphogenesis in myxococcus xanthus. | fruiting body formation in myxococcus xanthus involves three morphologic stages---rippling, aggregation, and sporulation---all of which are induced by the cell surface-associated c-signal. we analyzed the function of the devt protein, a novel component in the c-signal response pathway. a mutant carrying an in-frame deletion in the devt gene displays delayed aggregation and a cell autonomous sporulation defect, whereas it remains rippling proficient. to further define the function of devt, the me ... | 2002 | 11872704 |
| hydrogenases and hydrogen metabolism of cyanobacteria. | cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupsl) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxfuyh) which has the capacity to both take up and produce hydrogen. this review summarizes our knowledge about cyanobacterial hydrogenases ... | 2002 | 11875125 |
| genetic tools for cyanobacteria. | cyanobacteria are oxygenic photosynthetic bacteria that have been used increasingly to study diverse biological processes, including photosynthesis and its regulation; cell differentiation and n2 fixation; metabolism of nitrogen, carbon, and hydrogen; resistance to environmental stresses; and molecular evolution. many vectors and other genetic tools have been developed for unicellular and filamentous strains of cyanobacteria. transformation, electroporation, and conjugation are used for gene tra ... | 2002 | 11876404 |
| crystal structure of the opca integral membrane adhesin from neisseria meningitidis. | opca is an integral outer membrane protein from neisseria meningitidis, the causative agent of meningococcal meningitis and septicemia. it mediates the adhesion of n. meningitidis to epithelial and endothelial cells by binding to vitronectin and proteoglycan cell-surface receptors. here, we report the determination of the crystal structure of opca to 2.0 a resolution. opca adopts a 10-stranded beta-barrel structure with extensive loop regions that protrude above the predicted surface of the memb ... | 2002 | 11891340 |
| fasciclin domain proteins are present in nostoc symbionts of lichens. | differences in the soluble protein fraction between the freshly isolated cyanobiont of lichen peltigera membranacea, the corresponding free-living strain, and nostoc punctiforme were analyzed. one protein, which was among the most prominent proteins of the freshly isolated cyanobiont, was expressed at a lower level in the corresponding free-living strain and was not detected at all on the two-dimensional gels of n. punctiforme. this protein was partially sequenced, and the corresponding open rea ... | 2002 | 11916728 |
| peptide chain initiation in a species of nostoc and in chloroplasts of euglena gracilis. | | 1970 | 11945364 |
| evolution of sucrose synthesis. | cyanobacteria and proteobacteria (purple bacteria) are the only prokaryotes known to synthesize sucrose (suc). suc-p synthase, suc-phosphatase (spp), and suc synthase activities have previously been detected in several cyanobacteria, and genes coding for suc-p synthase (sps) and suc synthase (sus) have been cloned from synechocystis sp. pcc 6803 and anabaena (nostoc) spp., respectively. an open reading frame in the synechocystis genome encodes a predicted 27-kd polypeptide that shows homology to ... | 2002 | 11950997 |
| viability of dried filaments, survivability and reproduction under water stress, and survivability following heat and uv exposure in lyngbya martensiana, oscillatoria agardhii, nostoc calcicola, hormidium fluitans, spirogyra sp. and vaucheria geminata. | dried vegetative filaments of spirogyra sp., vaucheria geminata and nostoc calcicola died within 1/2, 1 and 4 h, respectively; those of hormidium fluitans, oscillatoria agardhii and lyngbya martensiana retained under similar storage conditions viability for 3, 5 and 10 d, respectively. the viability of dried vegetative filaments of l. martensiana, o. agardhii and h. fluitans decreased on storage at 20 degrees c in the dark. l. martensiana and o. agardhii tolerated 0.8 mol/l nacl. the resistance ... | 2002 | 11980272 |
| temporal variation in community composition, pigmentation, and f(v)/f(m) of desert cyanobacterial soil crusts. | summers on the colorado plateau (usa) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high uv and visible radiation. we investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. representative surface cores were sampled at the ene, wsw, and top microaspects of 20 individual soil crust pedicels at a single site in canyonlands national park, utah, in spring an ... | 2002 | 11984625 |
| isolation and characterization of mutants of two diazotrophic cyanobacteria tolerant to high concentrations of inorganic carbon. | diazotrophic heterocystous cyanobacteria nostoc calcicola and anabaena sp. arm 629 were investigated for their ability to grow in presence of sodium bicarbonate (nahco3) or carbon dioxide (co2) under cultural conditions. maximum growth was observed in 75 mm nahco3 and 5% co2 in n. calcicola and anabaena arm 629, respectively. although their growth rate declined, n. calcicola and anabaena sp. could tolerate upto 250 mm nahco3 and 20% co2, respectively. n-methyl-n'-nitro n nitrosoguanidine induced ... | 2002 | 12002405 |
| genome evolution of the cyanobacterium nostoc linckia under sharp microclimatic divergence at "evolution canyon," israel. | we describe the genomic dna diversity and divergence of the cyanobacterium nostoc linckia from "evolution canyon," a microsite consisting of ecologically contrasting slopes, south-facing slope (sfs) and north-facing slope (nfs), at lower nahal oren, mt. carmel, israel. the opposing slopes share their limestone lithology but vary greatly in their ecology, primarily because of different levels of solar radiation (which is six times higher on the sfs than on the nfs). the warm and xeric sfs display ... | 2001 | 12024256 |
| evidence for production of the phytohormone indole-3-acetic acid by cyanobacteria. | the ability of cyanobacteria to produce the phytohormone indole-3-acetic acid (iaa) was demonstrated. a colorimetric (salkowski) screening of 34 free-living and symbiotically competent cyanobacteria, that represent all morphotypes from the unicellular to the highly differentiated, showed that auxin-like compounds were released by about 38% of the free-living as compared to 83% of the symbiotic isolates. the endogenous accumulation and release of iaa were confirmed immunologically (elisa) using a ... | 2002 | 12029472 |
| the cyanobacterial trna(leu) (uaa) intron: evolutionary patterns in a genetic marker. | cyanobacterial trna(leu) (uaa) intron sequences from natural populations of nostoc and other cyanobacteria were compared. variation between the different introns was not randomly distributed but strongly restricted by the secondary and tertiary structure of the intron. although all nostoc sequences examined shared high similarity, differences were observed in one stem-loop. this stem-loop could be divided into two classes, both built up from two base pairing heptanucleotide repeats. size variati ... | 2002 | 12032241 |
| cellular fatty acids as chemotaxonomic markers of the genera anabaena, aphanizomenon, microcystis, nostoc and planktothrix (cyanobacteria). | the cellular fatty acid content of 22 cyanobacterial strains belonging to the genera anabaena, aphanizomenon, calothrix, cylindrospermum, nostoc, microcystis and planktothrix were analysed. the identities of the major peaks were confirmed by ms. correspondence analysis of the data revealed three distinct groups formed by the microcystis strains, the nostoc/planktothrix strains and the anabaena/aphanizomenon/cylindrospermum strains. the calothrix strain did not cluster with the other heterocystou ... | 2002 | 12054217 |
| [participation of extracellular polysaccharides in detoxication of cadmium ions by cyanobacteria nostoc muscorum]. | using the methods of absorption and fluorescence spectroscopy, histochemistry and micrography, the influence of cadmium in different concentrations on the exudation of exopolysaccharides by nostoc muscorum was studied to elucidate the possibility of distance detoxication of cadmium ions by the cyanobacterium with the participation of its exometabolites. the toxic action of cd was controlled by changes in biomass, trichomes morphology, and the photosynthetic apparatus of the cyanobacterium. the c ... | 2002 | 12068610 |
| isolation and characterization of a chlorate-resistant mutant (clo- r) of the symbiotic cyanobacterium nostoc anth: heterocyst formation and n(2)-fixation in the presence of nitrate, and evidence for separate nitrate and nitrite transport systems. | nostoc anth is a filamentous, heterocystous cyanobacterium capable of n(2)-fixation in the absence of combined nitrogen. a chlorate-resistant mutant (clo- r) of nostoc anth was isolated that differentiates heterocysts and fixes n(2) in the presence of nitrate, but not in the presence of nitrite or ammonium. the mutant lacks nitrate uptake and thereby also lacks induction of nitrate reductase activity by nitrate. however, this mutant is able to transport and assimilate nitrite, indicating that th ... | 2002 | 12070686 |
| cloning, overexpression, purification, and matrix-assisted refolding of devs (rv 3132c) histidine protein kinase of mycobacterium tuberculosis. | the devr-devs (rv 3133c-rv 3132c) two-component system of mycobacterium tuberculosis was identified in our laboratory by rna subtractive hybridization. this genetic system was predicted to encode a response regulator and histidine protein kinase, respectively. the putative histidine kinase protein devs was overexpressed to high levels in escherichia coli as a fusion protein with a hexahistidine tag, his(6)-devs201, in the form of inclusion bodies. here we report a "redox-based" method of matrix- ... | 2002 | 12071717 |
| molecular analysis of the dormancy response in mycobacterium smegmatis: expression analysis of genes encoding the devr-devs two-component system, rv3134c and chaperone alpha-crystallin homologues. | mycobacteria adapt to a decrease in oxygen tension by entry into a non-replicative persistent phase. it was shown earlier that the two-component system, devr-devs, was induced in mycobacterium tuberculosis and mycobacterium bovis bcg cultures during hypoxia, suggesting that it may play a regulatory role in their adaptation to oxygen limitation. the presence of a homologous genetic system in mycobacterium smegmatis was predicted by scanning its unfinished genome sequence with devr and devs genes ... | 2002 | 12076818 |
| genetic diversity of nostoc microsymbionts from gunnera tinctoria revealed by pcr-strr fingerprinting. | the cyanobacteria belonging to the genus nostoc fix atmospheric nitrogen, both as free-living organisms and in symbiotic associations with a wide range of hosts, including bryophytes, gymnosperms (cycads), the small water fern azolla (pteridophyte), the angiosperm genus gunnera, and fungi (lichens). the gunnera-nostoc symbiosis is the only one that involves a flowering plant. in chile, 12 species of gunnera have been described with a broad distribution in the temperate region. we examined the ge ... | 2002 | 12087423 |
| structures of the complexes of a potent anti-hiv protein cyanovirin-n and high mannose oligosaccharides. | the development of anti-human immunodeficiency virus (hiv) microbicides for either topical or ex vivo use is of considerable interest, mainly due to the difficulties in creating a vaccine that would be active against multiple clades of hiv. cyanovirin-n (cv-n), an 11-kda protein from the cyanobacterium (blue-green algae) nostoc ellipsosporum with potent virucidal activity, was identified in the search for such antiviral agents. the binding of cv-n to the heavily glycosylated hiv envelope protein ... | 2002 | 12110688 |
| molecular differentiation of the heterocystous cyanobacteria, nostoc and anabaena, based on complete nifd sequences. | the segregation of nostoc and anabaena into separate genera has been debated for some time. the nitrogen fixation gene nifd was completely sequenced from representatives of these genera and analyzed phylogenetically, by using the representatives of other genera of the heterocystous cyanobacteria as outgroups. we were clearly able to differentiate between nostoc and anabaena in all analyses used. our data suggest that nostoc and anabaena should remain as separate genera. | 2002 | 12177735 |
| biochemical characterization of a membrane-bound manganese-containing superoxide dismutase from the cyanobacterium anabaena pcc 7120. | the filamentous cyanobacterium anabaena pcc 7120 (now renamed nostoc pcc 7120) possesses two genes for superoxide dismutase (sod). one is an iron-containing (fesod) whereas the other is a manganese-containing superoxide dismutase (mnsod). localization experiments and analysis of the sequence showed that the fesod is cytosolic, whereas the mnsod is a membrane-bound homodimeric protein containing one transmembrane helix, a spacer region, and a soluble catalytic domain. it is localized in both cyto ... | 2002 | 12215453 |
| synergistic effect of deoxyanthocyanins from symbiotic fern azolla spp. on hrma gene induction in the cyanobacterium nostoc punctiforme. | the hrma gene of the n2-fixing cyanobacterium nostoc punctiforme functions in repressing the formation of transitory motile filaments, termed hormogonia, by plant-associated vegetative filaments. here, we report that anthocyanins can contribute to induction of hrma expression. aqueous extract from fronds of the fern azolla pinnata, a host of symbiotic nostoc spp., was found to be a potent inducer of hrma-luxab in n. punctiforme strain ucd 328. the hrma-luxab inducing activities of a. pinnata, as ... | 2002 | 12236594 |
| paenibacillus glycanilyticus sp. nov., a novel species that degrades heteropolysaccharide produced by the cyanobacterium nostoc commune. | a novel bacterial strain, ds-1t, was isolated that degrades heteropolysaccharide produced by the cyanobacterium nostoc commune. the isolate was identified by a combination of phenotypic characterization, cellular fatty acid analysis, dna base composition, dna-dna hybridization and 165 rrna gene sequence analysis. phylogenetic analysis placed strain ds-1t within the paenibacillus cluster on a phylogenetic tree and the phenotypic characteristics of this strain appear to be similar to those of paen ... | 2002 | 12361272 |
| analysis of the hli gene family in marine and freshwater cyanobacteria. | certain cyanobacteria thrive in natural habitats in which light intensities can reach 2000 micromol photon m(-2) s(-1) and nutrient levels are extremely low. recently, a family of genes designated hli was demonstrated to be important for survival of cyanobacteria during exposure to high light. in this study we have identified members of the hli gene family in seven cyanobacterial genomes, including those of a marine cyanobacterium adapted to high-light growth in surface waters of the open ocean ... | 2002 | 12399037 |
| quantifying nitrogen-fixation in feather moss carpets of boreal forests. | biological nitrogen (n) fixation is the primary source of n within natural ecosystems, yet the origin of boreal forest n has remained elusive. the boreal forests of eurasia and north america lack any significant, widespread symbiotic n-fixing plants. with the exception of scattered stands of alder in early primary successional forests, n-fixation in boreal forests is considered to be extremely limited. nitrogen-fixation in northern european boreal forests has been estimated at only 0.5 kg n ha(- ... | 2002 | 12410308 |
| the uv-b stimulon of the terrestrial cyanobacterium nostoc commune comprises early shock proteins and late acclimation proteins. | the uv-b and desiccation-tolerant terrestrial cyanobacterium nostoc commune was grown under defined uv irradiation. proteome changes were monitored in the membrane and the cytosolic and the extracellular fractions. tools were developed to separate stress-triggered from growth stage-dependent changes. uv-b changed the relative cellular concentration of 493 out of 1,350 protein spots at least by a factor of three, rendering the uv-b stimulon of n. commune the most complex one described so far. it ... | 2002 | 12410839 |
| cellular differentiation in the cyanobacterium nostoc punctiforme. | nostoc punctiforme is a phenotypically complex, filamentous, nitrogen-fixing cyanobacterium, whose vegetative cells can mature in four developmental directions. the particular developmental direction is determined by environmental signals. the vegetative cell cycle is maintained when nutrients are sufficient. limitation for combined nitrogen induces the terminal differentiation of heterocysts, cells specialized for nitrogen fixation in an oxic environment. a number of unique regulatory events an ... | 2002 | 12420158 |
| isolation of the gene for the b12-dependent ribonucleotide reductase from anabaena sp. strain pcc 7120 and expression in escherichia coli. | the gene for ribonucleotide reductase from anabaena sp. strain pcc 7120 was identified and expressed in escherichia coli. this gene codes for a 1,172-amino-acid protein that contains a 407-amino-acid intein. the intein splices itself from the protein when it is expressed in e. coli, yielding an active ribonucleotide reductase of 765 residues. the mature enzyme was purified to homogeneity from e. coli extracts. anabaena ribonucleotide reductase is a monomer with a molecular weight of approximatel ... | 2002 | 12426342 |
| [use of cyanobacteria for indication of toxic action of stachybotrys toxins]. | screening of cyanobacteria cultures for their sensitivity to the action of complex preparations of toxins from 18 strains of stachybotrys chartarum has been carried out with the purpose to search for new test-organisms to create a reliable system of biotesting of stachibotryotoxines. in contrast to other cultures of unicell (anacystis nidulans) and filamentous (anabaena sp., anabaena variabilis, nostoc linckia, plectonema boryanum) cyanobacteria used in the experiment, only one culture of unicel ... | 2002 | 12436869 |
| solution nmr structure and backbone dynamics of the psae subunit of photosystem i from synechocystis sp. pcc 6803. | psae is a small peripheral subunit of photosystem i (psi) that is very accessible to the surrounding medium. it plays an essential role in optimizing the interactions with the soluble electron acceptors of psi, ferredoxin and flavodoxin. the solution structure of psae from the cyanobacterium synechocystis sp. pcc 6803 has been investigated by nmr with a special emphasis on its protein dynamic properties. psae is characterized by a well-defined central core that consists of a five-stranded beta-s ... | 2002 | 12437347 |
| [formation of giant and ultramicroscopic forms of nostoc muscorum calu 304 during cocultivation with rauwolfia tissues]. | the study of heteromorphic nostoc muscorum calu 304 cells, whose formation was induced by 6- to 7-week cocultivation with the rauwolfia callus tissues under unfavorable conditions, revealed the occurrence of giant cell forms (gcfs) with a volume which was 35-210 times greater than that of standard cyanobacterial cells. some gcfs had an impaired structure of the murein layer of the cell wall, which resulted in the degree of impairment of the cell wall ranging from the mere loss of its rigidity to ... | 2002 | 12449632 |
| evidence for the involvement of a common genetic determinant in the control of thallium-resistant (tl1-r) phenotype and salinity-tolerant phenotype in the cyanobacterium nostoc muscorum. | | 2000 | 12483581 |
| biosynthesis of 4-methylproline in cyanobacteria: cloning of nose and nosf genes and biochemical characterization of the encoded dehydrogenase and reductase activities. | the biosynthesis of the unusual amino acid 4-methylproline in the nostoc genus of cyanobacteria was investigated on the genetic and enzymatic level. two genes involved in the biosynthesis were cloned and the corresponding enzymes, a zinc-dependent long-chain dehydrogenase and a delta(1)-pyrroline-5-carboxylic acid (p5c) reductase homologue, were overexpressed in escherichia coli and biochemically characterized. putative substrates were synthesized to test enzyme substrate specificities, and deut ... | 2003 | 12515465 |
| dna binding properties of the hrmr protein of nostoc punctiforme responsible for transcriptional regulation of genes involved in the differentiation of hormogonia. | nostoc punctiforme is an example of a filamentous cyanobacterium that is capable of differentiating non-growing cells that constitute gliding filaments termed hormogonia. these gliding filaments serve in short distance dispersal and as infective units in establishing a symbiosis with plants, such as the bryophyte anthoceros punctatus. mutants of n. punctiforme exist which show elevated levels of initial infection of a. punctatus as a consequence of repeated cycles of hormogonium differentiation. ... | 2003 | 12519206 |
| purification and properties of an enzyme capable of degrading the polysaccharide of the cyanobacterium, nostoc commune. | a novel nostoc commune-polysaccharide (nps)-degrading enzyme with a molecular mass of 128.5 kda was purified from paenibacillus glycanilyticus ds-1. the optimum ph and temperature of the enzyme activity were 5.5 and 35 degrees c, respectively. the enzyme completely degraded nps to oligosaccharides, ranging from tetra to hexasaccharides and could degrade the xylan weakly whereas xanthan, gellan, cellulose, curdlan and p-nitrophenyl-beta-d-xylopyranoside were not degraded. homology analysis of the ... | 2002 | 12562091 |
| relation between domain evolution, specificity, and taxonomy of the alpha-amylase family members containing a c-terminal starch-binding domain. | the alpha-amylase family (glycoside hydrolase family 13; gh 13) contains enzymes with approximately 30 specificities. six types of enzyme from the family can possess a c-terminal starch-binding domain (sbd): alpha-amylase, maltotetraohydrolase, maltopentaohydrolase, maltogenic alpha-amylase, acarviose transferase, and cyclodextrin glucanotransferase (cgtase). such enzymes are multidomain proteins and those that contain an sbd consist of four or five domains, the former enzymes being mainly hydro ... | 2003 | 12581203 |
| a two-component regulator of universal stress protein expression and adaptation to oxygen starvation in mycobacterium smegmatis. | we identified a response regulator in mycobacterium smegmatis which plays an important role in adaptation to oxygen-starved stationary phase. the regulator exhibits strong sequence similarity to devr/rv3133c of m. tuberculosis. the structural gene is present on a multigene locus, which also encodes a sensor kinase. a devr mutant of m. smegmatis was adept at surviving growth arrest initiated by either carbon or nitrogen starvation. however, its culturability decreased several orders of magnitude ... | 2003 | 12591871 |