| expression and processing of cyanobacterial mn-stabilizing protein in escherichia coli. | the woxa gene of cyanobacterium anacystis nidulans r2, which encodes the precursor of the mn-stabilizing protein involved in photosynthetic water oxidation, was found to be expressed in escherichia coli. the 30-kda expression product was indistinguishable from the authentic mature protein on sds/page. upon fractionation of e. coli cells, the expression product was co-precipitated with the membrane fraction, which is consistent with the water-insoluble nature of the authentic mature protein. anal ... | 1989 | 2689172 |
| expression of the cam-form of phospho(enol)pyruvate carboxylase and nucleotide sequence of a full length cdna from mesembryanthemum crystallinum. | we have determined the complete nucleotide sequence of a full length cdna encoding the crassulacean acid metabolism (cam) isogene of phospho(enol)pyruvate carboxylase (pepcase). the cdna clone, 3348 bp in length, was obtained from mrna isolated from mesembryanthemum crystallinum (common ice plant) which had undergone salt stress and subsequent induction of cam. the long open reading frame encodes pepcase (ec 4.1.1.31) with a predicted molecular mass of 110533 daltons. the deduced amino acid sequ ... | 1989 | 2710107 |
| prophylaxis of cyanobacterial and mushroom cyclic peptide toxins. | the pathogenicity of virulent cyclic peptide toxins of the cyanobacterium, microcystis aeruginosa, and the mushroom, amanita phalloides, was prevented in mice by pretreatment with a variety of chemically unrelated agents including hydrocortisone, shellac, certain diazo and triazine dyes and cyclosporine. a. despite the diverse nature of the protective agents, a feature commonly associated with protection was the ability to impair hepatic uptake of 51cr-labeled sheep erythrocytes, a function of h ... | 1989 | 2724139 |
| 6-desmethoxyhormothamnione, a new cytotoxic styrylchromone from the marine cryptophyte chrysophaeum taylori. | our previous chemical investigations of a yellow marine alga from puerto rico, tentatively identified as the tuft-forming cyanobacterium hormothamnion enteromorphoides, led to the isolation of a structurally novel cytotoxic styrylchromone natural product, hormothamnione [2]. continued chemical work with this organism has resulted in the isolation and spectroscopic structure elucidation of a closely related styrylchromone, 6-desmethoxyhormothamnione [1], which is also cytotoxic to cancer cells. t ... | 1989 | 2746254 |
| whole-cell biosensors for environmental monitoring. | concern over the pollution risk to drinking water from industry and agriculture is growing, and the need for continuous on-line monitoring recognised. there is increasing use of living organisms as the sensitive agent to detect the presence of pollutants, and whole-cell biosensors are seen to have particular advantages in such environmental monitoring. the development of a mediated amperometric biosensor, incorporating the cyanobacterium synechococcus as the biocatalyst, for on-line herbicide mo ... | 1989 | 2775317 |
| rapid microfilament reorganization induced in isolated rat hepatocytes by microcystin-lr, a cyclic peptide toxin. | the cyclic heptapeptide hepatotoxin microcystin-lr from the cyanobacterium microcystis aeruginosa induces rapid and characteristic deformation of isolated rat hepatocytes. we investigated the mechanism(s) responsible for cell shape changes (blebbing). our results show that the onset of blebbing was accompanied neither by alteration in intracellular thiol and ca2+ homeostasis nor by atp depletion. the irreversible effects were insensitive to protease and phospholipase inhibitors and also to thiol ... | 1989 | 2806414 |
| instability of tn5 inserts in cyanobacterial cloning vectors. | transposon tn5 was used to produce random insertions in two hybrid cloning vectors for the unicellular cyanobacterium anacystis nidulans. the transposon-containing plasmids were used to localize essential replication functions and to characterize the stability of large inserts in these vectors. the effect of the insertions on plasmid function was tested by transformation into a derivative of a. nidulans that had been cured of the endogenous plasmid used to construct the vectors. a region of appr ... | 1987 | 2820923 |
| molecular cloning and isolation of a cyanobacterial gene which increases the uv and methyl methanesulphonate survival of reca strains of escherichia coli k12. | the unicellular cyanobacterium gloeocapsa alpicola contains both photoreactivation and excision repair mechanisms for correcting uv-induced damage to its cellular dna. an 11.5 kb ecori fragment was isolated from a cosmid bank of g. alpicola and was shown to complement a reca deletion in escherichia coli s.17 and jc10289. these reca strains showed increased survival to uv and methyl methanesulphonate (mms) when transformed with the cyanobacterial dna fragment, and also showed filamentation in res ... | 1987 | 2821162 |
| light-induced charge separation in photosystem i at low temperature is not influenced by vitamin k-1. | the photoreduction of iron-sulfur centers was studied at low temperature in photosystem i particles from spinach and the cyanobacterium synechocystis 6803, which contain various amounts of vitamin k-1 (recently tentatively identified as the acceptor a1). the irreversible charge separation that was progressively induced at low temperature between p-700 and fa (or fb) by successive laser flashes was studied at 15 k. its maximum amount after a large number of flashes was shown to be fairly independ ... | 1987 | 2823891 |
| immunological and spectral characterization of partly purified cytochrome oxidase from the cyanobacterium synechocystis 6714. | membranes were isolated by french pressure cell extrusion of lysozyme-preincubated cells of the cyanobacterium synechocystis 6714 after growth in the presence of 0.4 m nacl for 4 days. these cells showed up to 6-fold respiratory activity (oxygen uptake) when compared to control cells. separation of plasma and thylakoid membranes revealed that the major part of cytochrome c oxidase was associated with the latter. immunoblotting of sodium dodecylsulfate polyacrylamide gel electrophorized membranes ... | 1987 | 2825695 |
| sulfide-dependent photosynthetic electron flow coupled to proton translocation in thylakoids of the cyanobacterium oscillatoria limnetica. | light-induced proton translocation coupled to sulfide-dependent electron transport has been studied in isolated thylakoids of the cyanobacterium oscillatoria limnetica. the thylakoids are obtained by osmotic shock of washed spheroplasts, prepared with glycine-betaine as the osmotic stabilizer. 13c nmr studies suggests that betaine is the major osmoregulator in o. limnetica. thylakoid preparations obtained from both sulfide-induced anoxygenic cells and noninduced oxygenic cells are capable of pro ... | 1987 | 2827581 |
| site-directed mutagenesis identifies a tyrosine radical involved in the photosynthetic oxygen-evolving system. | photosynthetic oxygen evolution takes place in the thylakoid protein complex known as photosystem ii. the reaction center core of this photosystem, where photochemistry occurs, is a heterodimer of homologous polypeptides called d1 and d2. besides chlorophyll and quinone, photosystem ii contains other organic cofactors, including two known as z and d. z transfers electrons from the site of water oxidation to the oxidized reaction center primary donor, p+.680, while d+. gives rise to the dark-stab ... | 1988 | 2829186 |
| the principal hydrogen donor for the herpes simplex virus type 1-encoded ribonucleotide reductase in infected cells is a cellular thioredoxin. | in this study herpes simplex virus type 1-encoded ribonucleotide reductase was shown to be able to utilize thioredoxin purified from the cyanobacterium anabaena variabilis as a hydrogen donor for the enzyme. an assay has been developed to search for proteins which can function as a hydrogen donor for the viral ribonucleotide reductase. a protein has been identified and purified to homogeneity from infected cell extracts by a combination of fast protein liquid chromatography and gel filtration. t ... | 1988 | 2832522 |
| cloning and characterization of a photolyase gene from the cyanobacterium anacystis nidulans. | a 2 kb fragment was isolated from an anacystis nidulans genomic dna library by hybridization with synthetic oligonucleotide probes derived from the n-terminal amino acid sequence of anacystis photolyase. this fragment contains a 1452 bp-long open reading frame encoding a polypeptide of 484 amino acids (mr 54475). antibodies raised against purified anacystis photolyase reacted with extracts of cells harboring fused genes between lacz of escherichia coli and this gene. a 40.7% similarity was found ... | 1988 | 2837735 |
| cloning and nucleotide sequence of the thrb gene from the cyanobacterium calothrix pcc 7601. | the cyanobacterium calothrix pcc 7601 thrb gene, encoding homoserine kinase (ec 2.7.1.39), was cloned via complementation of an escherichia coli threonine auxotroph, and its nucleotide sequence was determined. the comparison of the homoserine kinase amino acid sequences from calothrix pcc 7601, e. coli k12 and bacillus subtilis 168 indicates a closer relationship between cyanobacteria and bacillaceae than between cyanobacteria and enterobacteriaceae. sequence analysis of the 5' and 3' flanking r ... | 1987 | 2838727 |
| organization of the nif genes in cyanobacteria in symbiotic association with azolla and anthoceros. | the sizes of endonuclease digestion fragments of dna from cyanobacteria in symbiotic association with azolla caroliniana or anthoceros punctatus, or in free-living culture, were compared by southern hybridization using cloned nitrogenase (nif) genes from anabaena sp. pcc 7120 as probes. the restriction fragment pattern produced by cyanobacteria isolated from a. caroliniana by culture through symbiotic association with anthoceros differed from that of the major symbiotic cyanobacterium freshly se ... | 1988 | 2841912 |
| bacterial-type ferredoxin genes in the nitrogen fixation regions of the cyanobacterium anabaena sp. strain pcc 7120 and rhizobium meliloti. | the nucleotide sequence of a region located downstream of the nifb gene, both in the cyanobacterium anabaena sp. strain pcc 7120 and in rhizobium meliloti, has been determined. this region contains a gene (fdxn) whose predicted polypeptide product strongly resembles typical bacterial ferredoxins. cyanobacteria have not previously been shown to contain bacterial-type ferredoxins. the presence of this gene suggests that nitrogen-fixing cyanobacteria have at least four distinct ferredoxins. | 1988 | 2842320 |
| primary structure of cotranscribed genes encoding the rieske fe-s and cytochrome f proteins of the cyanobacterium nostoc pcc 7906. | the thylakoid membrane cytochrome b6-f complex (plastoquinol:oxidized-plastocyanin oxidoreductase, ec 1.10.99.1) catalyzes electron-transfer and proton-translocation reactions essential for oxygenic photosynthesis. we have isolated and determined the nucleotide sequences of the petc and peta genes encoding the rieske fe-s and cytochrome f polypeptides from the filamentous cyanobacterium nostoc pcc 7906. these genes occur as single genomic copies, are tightly linked, and, as indicated by hybridiz ... | 1988 | 2842748 |
| expression of a gene encoding a novel ferredoxin in the cyanobacterium synechococcus 6301. | a gene was discovered in the cyanobacterium synechococcus 6301 that encodes a protein highly related to members of the [2fe-2s] ferredoxin family found in chloroplasts and cyanobacteria. it follows a cluster of seven genes encoding subunits of the cyanobacterial atp synthase complex. it is transcribed as a monocistronic mrna of 408 nucleotide residues. transcription starts at a site 55 bp upstream of the initiator methionine codon. transcriptional initiation and termination signals with sequence ... | 1988 | 2843173 |
| characterization of the manganese o2-evolving complex and the iron-quinone acceptor complex in photosystem ii from a thermophilic cyanobacterium by electron paramagnetic resonance and x-ray absorption spectroscopy. | the mn donor complex in the s1 and s2 states and the iron-quinone acceptor complex (fe2+-q) in o2-evolving photosystem ii (ps ii) preparations from a thermophilic cyanobacterium, synechococcus sp., have been studied with x-ray absorption spectroscopy and electron paramagnetic resonance (epr). illumination of these preparations at 220-240 k results in formation of a multiline epr signal very similar to that assigned to a mn s2 species observed in spinach ps ii, together with g = 1.8 and 1.9 epr s ... | 1988 | 2843222 |
| effect of growth temperature on membrane dynamics in a thermophilic cyanobacterium: a spin label study. | a strain of synechococcus sp. was grown at its optimal growth temperature (58 degrees c) and at 38 degrees c, in order to investigate possible adaptations of membrane-related properties to growth temperature. light-induced electron transport in thylakoid membranes from both types of cells showed linear arrhenius plots with the same activation energy (48 kj/mol). membranes from cells grown at 58 degrees c had a higher temperature optimum (53 degrees c) than those from cells grown at 38 degrees c ... | 1988 | 2843232 |
| insertion sequence is2 in the cyanobacterium chlorogloeopsis fritschii. | a cloned dna fragment, previously demonstrated to encode ribulose bisphosphate carboxylase/oxygenase (rubisco) of chlorogloeopsis fritschii strain ccap1411/1b, is shown also to include the entire transposable element, is2, normally a resident in the escherichia coli genome. southern-blot hybridisation experiments confirm the presence of is2 in the c. fritschii genome. this finding adds a new and unrelated species to the known host range of this element and provides evidence of genetic transfer b ... | 1988 | 2844631 |
| characterization of two operons encoding the cytochrome b6-f complex of the cyanobacterium nostoc pcc 7906. highly conserved sequences but different gene organization than in chloroplasts. | we have isolated and determined the nucleotide and derived protein sequences for the four genes, petca and bd, which encode the cytochrome b6-f, electron-transfer complex of the filamentous cyanobacterium, nostoc pcc 7906. the primary structure and cotranscription of the petca genes encoding the rieske-fes (nuclear encoded in plants) and apocytochrome f proteins has been described previously (kallas, t., spiller, s., and malkin, r. (1988) proc. natl. acad. sci. u.s.a., in press). the petbd genes ... | 1988 | 2844767 |
| distinct fractions of genomic dna from cyanobacterium nostoc commune that differ in the degree of methylation. | | 1988 | 2854807 |
| use of streptavidin to detect biotin-containing proteins in plants. | a procedure to detect biotinyl proteins after fractionation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was developed. proteins were immobilized on nitrocellulose and biotin-containing proteins were detected by probing with 125i-streptavidin. using this procedure a small survey of biotinyl protein in plants was undertaken. in total four biotin-containing proteins were detected in higher plants of molecular weights 62,000, 50,000, 34,000, and 31,000. these biotinyl proteins were ... | 1985 | 2866733 |
| isolation and characterization of nitrogenase-derepressed mutant strains of cyanobacterium anabaena variabilis. | a positive selection method for isolation of nitrogenase-derepressed mutant strains of a filamentous cyanobacterium, anabaena variabilis, is described. mutant strains that are resistant to a glutamate analog, l-methionine-d,l-sulfoximine, were screened for their ability to produce and excrete nh4+ into medium. mutant strains capable of producing nitrogenase in the presence of nh4+ were selected from a population of nh4+-excreting mutants. one of the mutant strains (sa-1) studied in detail was fo ... | 1986 | 2867990 |
| properties of the cyanobacterial coupling factor atpase from spirulina platensis. i. electrophoretic characterization and reconstitution of photophosphorylation. | the coupling factor atpase (f1) from photosynthetic membranes of the cyanobacterium spirulina platensis was purified to homogeneity by a combination of ion-exchange chromatography and sucrose density gradient centrifugation. the atpase activity of purified spirulina f1 is latent but can be elicited by trypsin treatment, resulting in specific activities (caatpase) of 27-37 mumol pi min-1 mg protein-1. on denaturing sodium dodecyl sulfate-polyacrylamide gradient gels, spirulina f1 is resolved into ... | 1986 | 2868694 |
| differences in mrna levels in anabaena living freely or in symbiotic association with azolla. | azolla is a small water fern in whose leaf cavities the filamentous nitrogen-fixing cyanobacterium anabaena azollae is symbiotically associated. using cloned genes from anabaena 7120 for glutamine synthetase (gs), ribulose-1,5-bisphosphate (rubp) carboxylase, nitrogenase and the 32-kd protein of photosystem ii, mrna levels of the corresponding genes in the anabaena endosymbiont were studied by northern hybridization. in rna isolated from the endosymbiont there is a 10-fold reduction of gs transc ... | 1986 | 2869943 |
| effect of glutamine on growth and heterocyst differentiation in the cyanobacterium anabaena variabilis. | mutants of the cyanobacterium anabaena variabilis that were capable of increased uptake of glutamine, as compared with that in the parental strains, were isolated. growth of these mutants and their parental strains was measured in media containing n2, ammonia, or glutamine as a source of nitrogen. all strains grew well with any one of these sources of fixed nitrogen. much of the glutamine taken up by the cells was converted to glutamate. the concentrations of glutamine, glutamate, arginine, orni ... | 1986 | 2877968 |
| interaction, functional relations and evolution of large and small subunits in rubisco from prokaryota and eukaryota. | in early biological evolution anoxygenic photosynthetic bacteria may have been established through the acquisition of ribulose bisphosphate carboxylase-oxygenase (rubisco). the establishment of cyanobacteria may have followed and led to the production of atmospheric oxygen. it has been postulated that a unicellular cyanobacterium evolved to cyanelles which were evolutionary precursors of chloroplasts of both green and non-green algae. the latter probably diverged from ancestors of green algae as ... | 1986 | 2878448 |
| genes encoding the beta and epsilon subunits of the proton-translocating atpase from anabaena sp. strain pcc 7120. | the genes encoding the beta (atpb) and epsilon (atpe) subunits of the atpase from the cyanobacterium anabaena sp. strain pcc 7120 were cloned, and their sequences were determined. atpb and atpe are each single-copy genes in the anabaena genome. the two genes are separated by a 96-base-pair intergenic spacer and transcribed as a single mrna of 2.3 kilobases that initiates approximately 200 base pairs upstream of the atpb coding region. the predicted translation product of atpb has 81 and 68% amin ... | 1987 | 2878921 |
| regulation of glutamate dehydrogenase activity and ammonia production in a nitrogen fixing cyanobacterium. | a glutamate auxotroph was obtained in nostoc muscorum by induced mutagenesis with nitrosoguanidine. the metabolic pathway leading to glutamate synthesis was traced by selecting several enzymes. the strain was found to be lacking glutamate dehydrogenase. other enzymes, however, were normal in their activity including isocitric dehydrogenase, glutamine synthetase and glutamate synthase. nitrogen metabolism of the auxotroph and wild type was compared. the strain released exceedingly high amounts of ... | 1986 | 2880448 |
| dl-7-azatryptophan and citrulline metabolism in the cyanobacterium anabaena sp. strain 1f. | an alternative route for the primary assimilation of ammonia proceeds via glutamine synthetase-carbamyl phosphate synthetase and its inherent glutaminase activity in anabaena sp. strain 1f, a marine filamentous, heterocystous cyanobacterium. evidence for the presence of this possible alternative route to glutamate was provided by the use of amino acid analogs as specific enzyme inhibitors, enzymological studies, and radioistopic labeling experiments. the amino acid pool patterns of continuous cu ... | 1987 | 2880834 |
| expression of the larvicidal gene of bacillus sphaericus 1593m in the cyanobacterium anacystis nidulans r2. | a 3.6 kb hindiii dna fragment from bacillus sphaericus 1593m was cloned and expressed in escherichia coli and b. subtilis using phv33 as shuttle vector and in the cyanobacterium anacystis nidulans r2 with puc303 as shuttle vector. the level of toxin activity of the respective recombinant plasmids pgsp04 and pgsp12 against culex mosquito larvae was found to be the same in escherichia coli and in the cyanobacterium. | 1987 | 2890082 |
| genes encoding the alpha, gamma, delta, and four f0 subunits of atp synthase constitute an operon in the cyanobacterium anabaena sp. strain pcc 7120. | a cluster of genes encoding subunits of atp synthase of anabaena sp. strain pcc 7120 was cloned, and the nucleotide sequences of the genes were determined. this cluster, denoted atp1, consists of four f0 genes and three f1 genes encoding the subunits a (atpi), c (atph), b' (atpg), b (atpf), delta (atpd), alpha (apta), and gamma (atpc) in that order. closely linked upstream of the atp synthase subunit genes is an open reading frame denoted gene 1, which is equivalent to the unci gene of escherich ... | 1988 | 2900236 |
| formation of the chlorophyll precursor delta-aminolevulinic acid in cyanobacteria requires aminoacylation of a trnaglu species. | in the chloroplasts of higher plants and algae, the biosynthesis of the chlorophyll precursor delta-aminolevulinic acid (ala) involves at least three enzymes and a trna species. here we demonstrate that in cell extracts of the unicellular cyanobacterium synechocystis sp. strain pcc 6803 ala was formed from glutamate in a series of reactions in which activation of glutamate by glutamyl-trnaglu formation was the first step. the activated glutamate was reduced by a dehydrogenase which displayed trn ... | 1988 | 2900830 |
| glutamine synthetase from a cyanobacterium, phormidium lapideum: purification, characterization, and comparison with other cyanobacterial enzymes. | glutamine synthetase has been purified to homogeneity from cell extracts of a non-n2-fixing filamentous cyanobacterium, phormidium lapideum. the subunit molecular weight of the enzyme was determined as about 59,000 by sodium dodecyl sulfate gel electrophoresis. electron micrographs of the phormidium enzyme revealed a two-layered structure of regular hexagons (12 subunits per molecule), which markedly resembles the three-dimensional polypeptide backbone structure of the salmonella typhimurium glu ... | 1988 | 2907514 |
| the relationship of a prochlorophyte prochlorothrix hollandica to green chloroplasts. | it is generally accepted that chloroplasts arose from one or more endosymbiotic events between an ancestral cyanobacterium and a eukaryote. such an origin fits well in the case of the chloroplasts of rhodophytes that, like cyanobacteria, contain chlorophyll a and phycobilin pigments. the green chloroplasts from higher plants, green algae, and euglenoids however, contain chlorophyll b as well as chlorophyll a, and lack phycobilins. consequently, it has been suggested that they arose independently ... | 1989 | 2911389 |
| characterization of a cyanobacterial photosystem i complex. | a simple procedure is described for the preparation of photosystem i (psi) particles from triton x-100-solubilized thylakoid membranes of the unicellular cyanobacterium synechococcus 6301. the purified psi complex contained the full complement of antenna chlorophylls, 130 +/- 5/p700, displayed the electron paramagnetic resonance signals characteristic of iron-sulfur centers x, a, and b, and had a protein/chlorophyll ratio of 2.9. determination of the polypeptide composition, utilizing a uniforml ... | 1985 | 2981224 |
| three restriction endonucleases from anabaena flos-aquae. | three site-specific endonucleases, afli, aflii and afliii, have been partially purified from the cyanobacterium anabaena flos-aquae ccap 1403/13f. their recognition and cleavage specificities have been determined to be: (formula; see text) aflii and afliii are new specificities and may be useful in molecular cloning, as well as in the analysis of dna. the distribution of type ii restriction endonucleases in the cyanobacteria is briefly discussed. | 1985 | 2985742 |
| epr signals of redox active copper in edta washed membranes of the cyanobacterium synechococcus 6311. | a signal of cu2+ (g = 2.03) was detected by electron paramagmetic resonance spectroscopy in oxidized membrane preparations of synechococcus 6311. the membranes were prepared and washed in the presence of edta (10mm, ph 8.0) and, hence, were depleted of adventitious copper; the treatment also would remove any membrane-associated soluble redox proteins and other paramagnetic metal ions. 0.1% triton x-100 facilitated detection of the cu2+ signal which was fully reduced by dithionite or ascorbate pl ... | 1985 | 2988542 |
| cloning of phosphoenolpyruvate carboxylase gene from a cyanobacterium, anacystis nidulans, in escherichia coli. | the phosphoenolpyruvate carboxylase gene (ppc) from anacystis nidulans, a cyanobacterium (blue-green alga), was cloned in escherichia coli. chromosomal dna of a. nidulans was partially digested with sau3ai, and the obtained dna fragments were ligated in the bamhi site of pbr322. the hybrid plasmids were first transformed into e. coli k802 (hsdr-, hsdm+) to obtain the gene bank of a. nidulans. the bank consisted of about 12,000 clones. these hybrid plasmids were then transformed into e. coli pcr1 ... | 1985 | 2989256 |
| a new endonuclease recognizing the deoxynucleotide sequence ccnngg from the cyanobacterium synechocystis 6701. | a new sequence-specific endonuclease from the cyanobacterium synechocystis species pcc 6701 has been purified and characterized. this enzyme, seci, is unique in recognizing the nucleotide sequence: 5' -ccnngg-3' 3' -ggnncc-5' and cleaves it at the position indicated by the symbol. two other restriction endonucleases, secii and seciii, found in this organism are isoschizomers of mspi and mstii, respectively. | 1985 | 2997722 |
| molecular cloning and nucleotide sequence of a developmentally regulated gene from the cyanobacterium calothrix pcc 7601: a gas vesicle protein gene. | since the gas vesicle protein (gvp) is highly conserved among the different gas-vacuolate prokaryotes, a 29-mer oligonucleotide corresponding to a portion of the anabaena flos-aquae gvp gene was synthesized and used to isolate the gvp structural gene from calothrix pcc 7601 (= fremyella diplosiphon). gas vacuole production in this filamentous cyanobacterium is restricted to hormogonia which occur at a specific stage during the developmental cell cycle. the gvp gene (gvpa) was localized on a 709 ... | 1985 | 2997744 |
| expression of the escherichia coli lacz gene on a plasmid vector in a cyanobacterium. | a biphasic plasmid vector was used to introduce the escherichia coli k-12 lac operon into the unicellular cyanobacterium agmenellum quadruplicatum pr-6. the pr-6 transformants expressed beta-galactosidase at nearly as high a level as did escherichia coli transformants. in order to accomplish this, it was necessary to obtain pr-6 mutants that could be transformed by plasmids with unmodified recognition sites for the endogenous pr-6 restriction endonuclease aqu i. these mutants were generated by a ... | 1985 | 2997920 |
| nucleotide sequence of the phosphoenolpyruvate carboxylase gene of the cyanobacterium anacystis nidulans. | nucleotide sequence of the open reading frame (orf) for the phosphoenolpyruvate carboxylase gene (ppc) of the cyanobacterium anacystis nidulans was determined. the orf consists of 3159 bp and codes for 1053 amino acid (aa) residues. the codon usage of the ppc of a. nidulans is not so markedly different from that of the escherichia coli ppc, yet, in a. nidulans the preferred codons are aag for lysine and ccc for proline, whereas those are seldom used in the e. coli ppc. | 1985 | 2998946 |
| the role of respiration during adaptation of the freshwater cyanobacterium synechococcus 6311 to salinity. | growth of the freshwater cyanobacterium synechococcus 6311 under saline conditions stimulated respiration tenfold during the first 24 h, while growth and photosynthesis were inhibited. the elevated respiration rate was seen under both light and dark conditions, was uncoupler and cyanide sensitive, and did not decrease upon salt removal. membrane preparations from salt-grown cells exhibited a tenfold increase in cytochrome oxidase activity, while electron transfer rates from nadph to cytochrome c ... | 1986 | 3004347 |
| cloning and sequence analysis of cdna encoding active phosphoenolpyruvate carboxylase of the c4-pathway from maize. | a recombinant clone, pm52, containing cdna for maize phosphoenolpyruvate carboxylase (pepcase, ec 4.1.1.31) was isolated from a maize leaf cdna library constructed using an expression vector in escherichia coli. the screening of the clone was conveniently performed through its ability to complement the phenotype (glutamate requirement) of pepcase-negative mutant of e. coli. the enzyme encoded by this clone was identical with the major pepcase in maize, a key enzyme in the c4-pathway, as judged f ... | 1986 | 3005978 |
| self-cloning in the cyanobacterium anacystis nidulans r2: fate of a cloned gene after reintroduction. | functional analysis of cloned genes often makes use of complementation after introducing these genes into cells of a mutant strain. problems with this self-cloning step in the cyanobacterium anacystis nidulans r2 have been encountered, which were mainly due to recombinational instability of gene and vector after transformation. therefore, conditions determining the exchange of material between chromosome, insert and plasmids were studied to achieve the necessary stability. the fate of plasmid pm ... | 1985 | 3006100 |
| identification and sequence of a gene required for a developmentally regulated dna excision in anabaena. | vegetative cells of the cyanobacterium anabaena contain an 11 kb dna element within the coding region of the nifd gene. this element is excised by site-specific recombination between directly repeated 11 bp sequences at each of its ends during differentiation of nitrogen-fixing cells called heterocysts. site-specific recombination, leading to the same rejoined nifd gene, was observed during propagation in e. coli of a fragment containing the 11 kb element and flanking sequences. an assay for exc ... | 1986 | 3006922 |
| endogenous energy supply to the plasma membrane of dark aerobic cyanobacterium anacystis nidulans: atpase-independent efflux of h+ and na+ from respiring cells. | the ejection of protons from oxygen-pulsed cells and the gradients of na+ concentration (na+o/na+i at 150 mm external nacl) and proton electrochemical potential (delta mu h+) across the plasma membrane of anacystis nidulans were studied in response to dark endogenous energy supply. saturating concentrations of the f0f1-atpase inhibitors dicyclohexylcarbodiimide (f0) and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (f1) eliminated oxidative phosphorylation and lowered the atp level from 2.6 +/- 0.15 to ... | 1986 | 3010878 |
| exogenous energy supply to the plasma membrane of dark anaerobic cyanobacterium anacystis nidulans: thermodynamic and kinetic characterization of the atp synthesis effected by an artificial proton motive force. | the net synthesis of atp in dark anaerobic cells of anacystis nidulans subjected to acid jumps and/or valinomycin pulses was characterized thermodynamically and kinetically. maximum initial rates of 75 nmol atp/min per mg dry weight at an applied proton motive force of -350 mv were obtained, the flow-force relationship (rate of atp synthesis vs applied proton motive force) being linear between -240 and -320 mv irrespective of the source of the proton motive force. the pulse-induced atp synthesis ... | 1986 | 3010879 |
| immunological identification of aa3-type cytochrome oxidase in membrane preparations of the cyanobacterium anacystis nidulans. | membranes were isolated from the cyanobacterium anacystis nidulans by french press extrusion of lysozyme-treated cells. the membranes were solubilized with sodium dodecylsulfate and subjected to denaturing polyacrylamide gel electrophoresis. separated polypeptides were transferred to nitrocellulose by western blotting, and incubated with antibodies against aa3-type cytochrome oxidase of paracoccus denitrificans; antibodies against subunits i and ii, and against the holoenzyme, were used and gave ... | 1986 | 3010964 |
| genes from the cyanobacterium agmenellum quadruplicatum isolated by complementation: characterization and production of merodiploids. | the isolation of several biosynthetic genes from a cyanobacterium, agmenellum quadruplicatum, by complementation of auxotrophic mutations in escherichia coli, and their partial characterization, is described. although our search for such genes has not been exhaustive, it appears that complementation of e. coli mutations may be of limited utility for the identification and/or isolation of cyanobacterial genes. despite some overlap in the complementation abilities of these isolated cyanobacterial ... | 1986 | 3011598 |
| hydrogenases of phototrophic microorganisms. | this review surveys recent work done in the laboratory of the author and related laboratories on the properties and possible practical applications of hydrogenases of phototrophic microorganisms. homogeneous hydrogenase preparations were obtained from purple non-sulfur (rhodospirillum rubrum s1, rhodobacter capsulatus b10) and purple sulfur (chromatium vinosum d, thiocapsa roseopersicina bbs) bacteria, and from the green sulfur bacterium chlorobium limicola forma thiosulfatophilum l; highly puri ... | 1986 | 3015244 |
| multimodal liquid chromatography columns for the separation of proteins in either the anion-exchange or hydrophobic-interaction mode. | several high-performance stationary phases suitable for protein chromatography were synthesized. columns packed with these materials could be operated independently in either the anion-exchange or hydrophobic-interaction mode. two approaches were used to prepare these materials. in the first method, a polyamine was adsorbed on the surface of macroporous silica and then crosslinked with a multifunctional oxirane. the hydrophobicity of the crosslinking agent and the extent of interconnection were ... | 1986 | 3016003 |
| three partial reactions of ribulose-bisphosphate carboxylase require both large and small subunits. | three partial reactions of ribulose-bisphosphate carboxylase/oxygenase were measured in the presence and absence of small subunits using the enzyme from the cyanobacterium, synechococcus acmm 323, whose small subunits may be reversibly dissociated from its octameric, large-subunit core. these partial reactions were: the exchange of the proton at c-3 of the substrate, ribulose 1,5-bisphosphate, with the medium which is indicative of c-2, c-3 enolization; the hydrolysis of the 6-carbon reaction in ... | 1986 | 3017966 |
| controlled gene expression utilising lambda phage regulatory signals in a cyanobacterium host. | this study presents plasmid systems that utilize regulatory signals of bacteriophage lambda to accomplish regulated expression of cloned genes in an a. nidulans r2 derivative strain. an operator-promoter region and the temperature-sensitive repressor gene ci857 of bacteriophage lambda were employed. linked to a cyanobacterial replicon, the plasmid vectors efficiently transformed anacystis and were stably maintained within this host. the cat structural gene, encoding chloramphenicol acetyltransfe ... | 1986 | 3018433 |
| [recombinant plasmids capable of integration into the chromosome of the cyanobacterium anacystis nidulans r2]. | recombinant plasmids, series piab and piah, have been constructed by insertion of bamhi or hindiii chromosomal fragments from anacystis nidulans r2 into the tet gene of plasmid pacyc184. plasmids piab and piah are stably maintained in escherichia coli cells and transfer the cmr marker in transformation of anacystis nidulans. blot hybridization technique has shown the formation of cmr clones in transformation to result from integration of plasmid pacyc184 with the chromosome of cyanobacterium. | 1985 | 3025685 |
| [plasmids of the cyanobacterium synechocystis sp. 6803]. | three cryptic plasmids have been isolated from cyanobacterium synechocystis sp. 6803::pss2 (1.4 md), pss3 (36 md), pss4 (60 md). plasmid dna was isolated in cs-cl-eb density gradient and analyzed by gel electrophoresis and electron microscopy by gel electrophoresis and electron microscopy techniques. the restriction map is constructed for plasmid pss2 having the cleavage sites for sau3a, hincii, hindiii, mspi restriction endonucleases. the plasmid may be used to construct the recombinant vector ... | 1985 | 3025718 |
| ferredoxin-thioredoxin reductase, an iron-sulfur enzyme linking light to enzyme regulation in oxygenic photosynthesis: purification and properties of the enzyme from c3, c4, and cyanobacterial species. | ferredoxin-thioredoxin reductase (ftr), an enzyme involved in the light regulation of chloroplast enzymes, was purified to homogeneity from leaves of spinach (a c3 plant) and corn (a c4 plant) and from cells of a cyanobacterium (nostoc muscorum). the enzyme is a yellowish brown iron-sulfur protein, containing four nonheme iron and labile sulfide groups, that catalyzes the activation of nadp-malate dehydrogenase and fructose 1,6-bisphosphatase in the presence of ferredoxin and of thioredoxin m an ... | 1987 | 3028266 |
| determination of dissolved oxygen in photosynthetic systems by nitroxide spin-probe broadening. | concentrations of dissolved oxygen were monitored by following the width of the midfield line of the electron spin resonance spectrum of a nitroxide spin-probe. measurements of peak-to-trough widths of first derivative spectra yielded accurate data over a high range of o2 concentrations (up to 5mm). continuous traces of second harmonic line heights yielded similar results and proved to be advantageous for kinetic measurements, but were nonlinear and less sensitive at o2 levels above 2 mm. photos ... | 1987 | 3028269 |
| molecular cloning of a reca-like gene from the cyanobacterium anabaena variabilis. | a reca-like gene isolated from the cyanobacterium anabaena variabilis was cloned and partially characterized. when introduced into escherichia coli reca mutants, the 7.5-kilobase-pair plasmid-borne dna insert restored resistance to methyl methanesulfonate and uv irradiation, as well as recombination proficiency when measured by hfr-mediated conjugation. the cyanobacterial reca gene restored spontaneous but not mitomycin c-induced prophage production. restriction analysis and subcloning yielded a ... | 1987 | 3032896 |
| [bireplicon vector plasmids for the cyanobacterium synechocystis 6803 and escherichia coli]. | | 1987 | 3034540 |
| different recombination site specificity of two developmentally regulated genome rearrangements. | in the absence of a combined nitrogen source, such as ammonia, approximately every tenth vegetative cell along filaments of the cyanobacterium anabaena develops into a heterocyst, a terminally differentiated cell that is morphologically and biochemically specialized for nitrogen fixation. at least two specific dna rearrangements involving the nitrogen-fixation (nif) genes occur during heterocyst differentiation, one within the nifd gene and the other near the nifs gene. the two rearrangements ha ... | 1987 | 3035382 |
| 23na and 31p nmr studies of the effects of salt stress on the freshwater cyanobacterium synechococcus 6311. | we have used 23na and 31p nuclear magnetic resonance (nmr) spectroscopy to elucidate some of the bioenergetic changes that occur in the freshwater cyanobacterium synechococcus 6311 after a transition from growth medium (na concentration 0.01 m) to medium containing 0.5 m nacl. 23na nmr analysis showed na rapidly penetrates the cells under dark aerobic conditions; cells grown for several days in high salt medium, however, reestablish a low internal sodium content, comparable to control cells. for ... | 1987 | 3038026 |
| the organization and sequence of the genes for atp synthase subunits in the cyanobacterium synechococcus 6301. support for an endosymbiotic origin of chloroplasts. | the nucleotide sequence has been determined of two regions of dna cloned from the cyanobacterium synechococcus 6301. the larger, 8890 base-pairs in length, contains a cluster of seven genes for subunits of atp synthase. the order of the genes is a:c:b':b:delta:alpha:gamma, b' being a duplicated and diverged form of b. as in the escherichia coli unc operon, the a gene is preceded by a gene for a small hydrophobic and basic protein. the hydrophobic profile of the potential gene product suggests th ... | 1987 | 3041005 |
| membrane electrogenesis and sodium transport in filamentous nitrogen-fixing cyanobacteria. | transport of na+ and its relationship with membrane potential (delta psi m) was examined in anabaena l-31 (a fresh water cyanobacterium) and anabaena torulosa (a brackish water cyanobacterium) which require na+ for diazotrophic growth. the data on the effect of n,n'-dicyclohexylcarbodiimide indicated that delta psi m was generated by electrogenic proton extrusion predominantly mediated by atpase(s). in addition, operation of a plasmalemmabound, non-atp-requiring, h+-pumping terminal oxidase was ... | 1986 | 3080316 |
| photoheterotrophic growth of agmenellum quadruplicatum pr-6. | the unicellular cyanobacterium agmenellum quadruplicatum pr-6 grows in the presence of light on agar containing 10 microm 3-(3,4 dichlorophenyl)-1,1-dimethylurea and 1 to 30 mm glycerol. a derivative strain, pr-6g2, was tolerant of 100 mm glycerol. photoheterotrophic growth conditions had little effect on transformation competence but did decrease the viability of single cells plated onto agar, particularly cells of the parent strain. | 1986 | 3080411 |
| isolation of an intrinsic antenna chlorophyll a-protein from the photosystem i reaction center complex of the thermophilic cyanobacterium synechococcus sp. | a chlorophyll-protein was isolated from a synechococcus p700-chlorophyll a-protein complex free from small subunits (cp1-e) by sodium dodecyl sulfate (sds)-polyacrylamide gel electrophoresis after treatment with 2% 2-mercaptoethanol and 2% sds. in contrast to cp1-e which, when electrophoresed under denaturating conditions, showed two polypeptide bands of 62 and 60 kda, the chlorophyll-protein contained only the 60-kda polypeptide and hence is called cp60. the yield of cp60 was maximal with 1-2% ... | 1986 | 3080948 |
| transport and accumulation of nickel ions in the cyanobacterium anabaena cylindrica. | the uptake of nickel ions by the cyanobacterium anabaena cylindrica was studied. nickel transport was dependent on the membrane potential of the cells and the rate of uptake was decreased in the dark or by the addition of inhibitors, including uncouplers and electron transport inhibitors, which decreased or abolished the membrane potential of cells. the transport process obeyed hyperbolic kinetics, with a high affinity (apparent km = 17 +/- 11 (sem) nm) and low turnover number (maximum velocity ... | 1986 | 3080951 |
| evidence for direct repression of nitrogenase by ammonia in the cyanobacterium anabaena cylindrica. | the nitrogenase activity of the cyanobacterium anabaena cylindrica was repressed upon addition of ammonium salts after preincubation in the presence of a concentration of l-methionine-dl-sulfoximine sufficient to totally inhibit glutamine synthetase. repression was also observed when urea was added to cells in the presence of the glutamine synthetase inhibitor. measurements of ammonia concentrations were made in each case and provided evidence that ammonia itself is a primary regulator of nitrog ... | 1986 | 3080996 |
| stable transformation of the cyanobacterium synechocystis sp. pcc 6803 induced by uv irradiation. | irradiation of the photoheterotrophic cyanobacterium synechocystis sp. pcc 6803 with low levels of uv light allows for stable, integrative transformation of these cells by heterologous dna. in this system, transformation does not rely on an autonomously replicating plasmid and is independent of homologous recombination. cells treated with uv light in the absence of dna and cells given dna but not exposed to uv do not yield antibiotic-resistant colonies in platings of up to 2 x 10(8) cells. optim ... | 1986 | 3081493 |
| phenylalanyl-trna synthetase from chloroplasts of a higher plant (phaseolus vulgaris). purification and comparison of its structural, functional, and immunological properties with those of the enzymes from the corresponding cytoplasm, the cyanobacterium anacystis nidulans, and the photosynthetic green sulfur bacterium chlorobium limicola. | chloroplastic phenylalanyl-trna synthetase from bean leaves is purified under optimal protective conditions over 4,900-fold. its apparent molecular weight is 78,000, as determined by gel filtration, with a dimeric subunit structure of alpha beta (alpha = 33,000 and beta = 42,000), as determined by sodium dodecyl sulfate gel electrophoresis. this indicates a drastic size reduction of 40% for each subunit compared to the corresponding cytoplasmic enzyme and a unique quaternary structure. heterolog ... | 1986 | 3081498 |
| organization of the genes for protein synthesis elongation factors tu and g in the cyanobacterium anacystis nidulans. | the genes for protein synthesis elongation factors tu and g were cloned from the cyanobacterium anacystis nidulans. the locations of these genes were mapped within the cloned dna fragment by hybridization with escherichia coli probes. the organization of the cloned fragment and the dna flanking it in the a. nidulans chromosome was also determined. the elongation factor tu and g genes are adjacent to one another and in the same 5'-to-3' orientation. in contrast to other gram-negative bacteria, a. ... | 1986 | 3082860 |
| effect of tryptophan on 2,4-dichlorophenoxyacetic acid toxicity in the nitrogen-fixing-cyanobacterium nostoc linckia. | the combined effect of a hormone weed killer 2,4-dichlorophenoxyacetic acid (2,4-d) and an amino acid (tryptophan) has been studied on growth and heterocyst differentiation in the cyanobacterium nostoc linckia. 2.4-d at 100 micrograms/ml stimulated growth and heterocyst frequency in combined nitrogen-free medium while its higher concentrations inhibited both. tryptophan under similar conditions promoted much growth yield with 3-4 fold enhanced heterocyst frequency than the control. such heterocy ... | 1986 | 3083089 |
| method for determining the temporal response of microbial phosphate transport affinity. | nutrient transport affinities of nutrient-starved microbial populations were measured as initial slopes of plots of limiting-nutrient transport rates versus extracellular limiting-nutrient concentrations. a method was devised for the determination of soluble reactive phosphate (pi) affinity in pi-limited continuous culture (at), which was then used as an indicator of the effects of light/dark cycle (ld) perturbations on the temporal pi transport abilities of three species of freshwater algae. ce ... | 1986 | 3083772 |
| hydroperoxide metabolism in cyanobacteria. | the enzymes involved in antioxidative activity and the cellular content of the antioxidants glutathione and ascorbate in the cyanobacteria nostoc muscorum 7119 and synechococcus 6311 have been examined for their roles in hydroperoxide removal. high activities of ascorbate peroxidase and catalase were found in vegetative cells of both species and in the heterocysts of n. muscorum. the affinity of ascorbate peroxidase for h2o2 was 15- to 25-fold higher than that of catalase. increased activity of ... | 1986 | 3083778 |
| interaction of fructose with the glucose permease of the cyanobacterium synechocystis sp. strain pcc 6803. | fructose was bactericidal for the cyanobacterium synechocystis sp. strain pcc 6803. each of ten independently isolated fructose-resistant mutants had an alteration of the glucose transport system, measured as uptake of glucose or of 3-o-methyl-d-glucose. in the presence of the analog, the wild-type synechocystis strain was protected against fructose. two mutants altered in photoautotrophy were also isolated. | 1986 | 3084453 |
| transformation of the cyanobacterium anacystis nidulans 6301 with the escherichia coli plasmid pbr322. | anacystis nidulans 6301 has been transformed in the light to ampicillin resistance with the plasmid pbr322. permeaplasts prepared by 2-hr treatment of cells with lysozyme and edta are transformed with a 50-fold higher efficiency than that observed for cells. beta-lactamase is present in a. nidulans transformed either with pbr322 or the plasmid pch1 as evidenced by hydrolysis of the beta-lactam ring of nitrocefin in extracts of transformants. beta-lactamase also can be immunoprecipitated from ext ... | 1986 | 3085098 |
| effect of toxin from the cyanobacterium microcystis aeruginosa on ultrastructural morphology and actin polymerization in isolated hepatocytes. | freshly isolated rat hepatocytes incubated with the hepatotoxin from the cyanobacterium microcystis aeruginosa are rapidly deformed (blebbed). transmission electron microscopy shows the appearance of unusual intracellular structures and rearrangement of cellular organelles, without any change in the polymerization state of actin. cytochalasin e (20 microm), a fungal metabolite that causes blebbing of hepatocytes, had no significant effect on the polymerization state of cellular actin, but if mic ... | 1986 | 3085291 |
| paralytic shellfish poisons produced by the freshwater cyanobacterium aphanizomenon flos-aquae nh-5. | a single filament clonal isolate of aphanizomenon flos-aquae was made from a water bloom sample taken at a small pond near durham, new hampshire, in 1980. when batch cultured the strain was toxic to mice and had an i.p. ld50 of about 5.0 mg/kg. using an extraction procedure originally designed for paralytic shellfish poisons and other neurotoxins of freshwater cyanobacteria, a purification method was developed. the procedure involved acidified water/ethanol extraction of the cells followed by ul ... | 1986 | 3085292 |
| genetic mapping of the chromosome of the cyanobacterium, anabaena variabilis. proximity of the structural genes for nitrogenase and ribulose-bisphosphate carboxylase. | a cosmid library of dna from the chromosome of the nitrogen-fixing cyanobacterium, anabaena variabilis, has been organized into about 40 linkage groups on the basis of cosmid-cosmid hybridization. nitrogenase and ribulose-bisphosphate carboxylase are protein complexes that are, respectively, active in heterocysts and absent from vegetative cells, and active in vegetative cells and absent from heterocysts. the structural genes for the proteins of these two complexes are found to be in close proxi ... | 1986 | 3086317 |
| genes encoding major light-harvesting polypeptides are clustered on the genome of the cyanobacterium fremyella diplosiphon. | the polypeptide composition of the phycobilisome, the major light-harvesting complex of prokaryotic cyanobacteria and certain eukaryotic algae, can be modulated by different light qualities in cyanobacteria exhibiting chromatic adaptation. we have identified genomic fragments encoding a cluster of phycobilisome polypeptides (phycobiliproteins) from the chromatically adapting cyanobacterium fremyella diplosiphon using previously characterized dna fragments of phycobiliprotein genes from the eukar ... | 1986 | 3086870 |
| the pharmacology of anatoxin-a(s), a neurotoxin produced by the freshwater cyanobacterium anabaena flos-aquae nrc 525-17. | anatoxin-a(s) [antx-a(s)] is produced by anabaena flos-aquae clone nrc 525-17 and is different from anatoxin-a, a known depolarizing agent produced by a. flos-aquae nrc 44-1. purification of antx-a(s) from lyophilized cells involved extraction with 1.0 m acetic acid: ethanol (80:20), column chromatography (sephadex g-15 and cm-sephadex c-25) and high performance liquid chromatography. purified toxin has an ld50 (i.p., mouse) of approximately 50 micrograms/kg. gross pharmacological tests of antx- ... | 1986 | 3087030 |
| lethal potency and tissue distribution of 125i-labelled toxic peptides from the blue-green alga microcystis aeruginosa. | toxic heptapeptides from a water bloom of the cyanobacterium microcystis aeruginosa were purified by hplc. the unoxidised fraction was iodinated with 125i plus 127i by the lactoperoxidase/h2o2 method, further purified by hplc, and the non-iodinated and three iodinated fractions administered i.p. to male mice. all iodinated fractions were toxic, with symptoms and pathological lesions of the liver identical with those caused by non-iodinated peptide. radioactivity was concentrated in the liver of ... | 1986 | 3087033 |
| identification of a carotenoid-binding protein in the cytoplasmic membrane from the heterotrophic cyanobacterium synechocystis sp. strain pcc6714. | we isolated a carotenoid-binding protein from the cytoplasmic membrane of the cyanobacterium synechocystis sp. strain pcc6714. the polypeptide demonstrated a characteristic mobility shift when electrophoresed in lithium dodecyl sulfate-polyacrylamide gels. the protein migrated with an apparent molecular mass of 35 kilodaltons when solubilized at 0 degrees c, but after solubilization at 70 degrees c, the protein migrated as a 45-kilodalton species. the carotenoid-binding protein accumulated only ... | 1986 | 3087963 |
| freeze-fracture analysis of thylakoid membranes and photosystem i and ii enriched fractions from phormidium laminosum. | thylakoid membranes of the thermophilic cyanobacterium phormidium laminosum have been fractionated into photosystem ii and photosystem i particles. these fractions have been characterized by their partial electron transport activities, and biochemical and spectral properties. exoplasmic fracture face and protoplasmic fracture face particles in the unfractionated thylakoid membranes were shown to correspond in size to particles in freeze-fractured photosystem ii and photosystem i fractions, respe ... | 1986 | 3088002 |
| mutagenesis by ethidium bromide, proflavine and mitomycin c in the cyanobacterium nostoc sp. | ethidium bromide, proflavine, and mitomycin c were strongly lethal but weakly mutagenic to the cyanobacterium nostoc sp. with a view to studying the mode of action of these weak mutagens, their binding to nostoc dna was studied. the spectral changes resulting from the binding of these mutagens to the dna in vitro indicated that probably only electrostatic forces may be involved in the mutagen-dna binding. a similar low level of dna binding in vivo would explain the weakly mutagenic action of the ... | 1986 | 3088444 |
| characterization of cyanobacterial ferredoxin-nadp+ oxidoreductase molecular heterogeneity using chromatofocusing. | chromatofocusing has been used as an analytical tool to check preparations of the enzyme ferredoxin-nadp+ oxidoreductase (ec 1.18.1.2) purified in either the presence or absence of the serine protease inhibitor phenylmethylsulfonyl fluoride from the cyanobacterium anabaena sp. strain 7119. only one isoelectric species was found when the crude extract was processed in the presence of the protease inhibitor. nevertheless, when the inhibitor was omitted, four ionic forms of the enzyme--showing appa ... | 1986 | 3089056 |
| purification, properties, and oligomeric structure of glutathione reductase from the cyanobacterium spirulina maxima. | glutathione reductase [nad(p)h:gssg oxidoreductase ec 1.6.4.2] from cyanobacterium spirulina maxima was purified 1300-fold to homogeneity by a simple three-step procedure involving ammonium sulfate fractionation, ion exchange chromatography on deae-cellulose, and affinity chromatography on 2',5'-adp-sepharose 4b. optimum ph was 7.0 and enzymatic activity was notably increased when the phosphate ion concentration was increased. the enzyme gave an absorption spectrum that was typical for a flavopr ... | 1986 | 3089164 |
| role of the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase in the activation process. | the large (a) and small (b) subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase (ec 4.1.1.39) from the cyanobacterium aphanothece halophytica and from the purple sulfur photosynthetic bacterium chromatium vinosum (strain d) were separated by sucrose density gradient centrifugation at low ionic strength and alkaline ph (9.3), respectively. it was found that subunit b enhances the extent of activation by co2 and mg2+ at equilibrium of the two homologous enzymes consisting of aphanothece la ... | 1986 | 3089168 |
| influence of very low doses of ionizing radiation on synechococcus lividus metabolism during the initial growth phase. | previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the cyanobacterium synechococcus lividus. this modification of cell proliferation occurred during the first doubling. in this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. incubation of the cells in a new medium induced a high superoxide dismutase (ec 1.15.1.1, sod) activity at the 18th hour and a degrada ... | 1986 | 3089188 |
| crystal structure analysis and refinement at 2.5 a of hexameric c-phycocyanin from the cyanobacterium agmenellum quadruplicatum. the molecular model and its implications for light-harvesting. | the crystal structure of the light-harvesting protein-pigment complex c-phycocyanin from the cyanobacterium agmenellum quadruplicatum has been determined by patterson search techniques on the basis of the molecular model of c-phycocyanin from mastigocladus laminosus. the crystal unit cell (space group p321) contains three (alpha beta)6 hexamers centred on the crystallographic triads. the hexamer at the origin of the unit cell exhibits crystallographic 32 point symmetry. the other two hexamers (i ... | 1986 | 3090271 |
| functional linkage between phycobilisome and reaction center in two phycobilisome oxygen-evolving photosystem ii preparations isolated from the thermophilic cyanobacterium synechococcus sp. | photosystem ii oxygen-evolving preparations with attached phycobilisomes were isolated from the thermophilic cyanobacterium synechococcus sp. with beta-octylglucoside or digitonin. fluorescence emission spectra of the two preparations determined at 77 k largely lacked a far red band which originates from photosystem i. the spectrum of the digitonin preparation was otherwise similar to that of intact cells, whereas the beta-octylglucoside preparation showed a pronounced band at 687 nm, which is c ... | 1986 | 3090938 |
| immunological characterization of photosystem ii chlorophyll-binding proteins from the cyanobacterium, aphanocapsa 6714. | chlorophyll-binding proteins from the cyanobacterium aphanocapsa 6714 were identified by immunoblotting procedures. three chlorophyll-binding complexes, cpiii', cpiiia, and cpiiib, were associated with psii. cpiii' likely serves as an' antenna to psii in aphanocapsa since it could be removed from active psii core preparations without loss of activity. the cpiii' proteins cross-reacted to antibodies prepared against the maize psii light-harvesting complex, lhc-ii. the cpiiia polypeptides cross-re ... | 1986 | 3091588 |
| linker polypeptides of the phycobilisome from the cyanobacterium mastigocladus laminosus. i. isolation and characterization of phycobiliprotein-linker-polypeptide complexes. | phycobilisomes from the cyanobacterium mastigocladus laminosus cultured in white and red light were isolated and compared with respect to the phycoerythrocyanin (pec) and linker polypeptide contents. it was verified that the production of pec is induced by low light intensities. a pec complex, (alpha pec beta pec)6lr34.5,pec, and a phycocyanin (pc) complex, (alpha pc beta pc)6lr34.5,pc, were isolated from phycobilisomes by cellex-d anion exchange chromatography and sucrose density gradient centr ... | 1986 | 3092840 |
| linker polypeptides of the phycobilisome from the cyanobacterium mastigocladus laminosus. ii. amino-acid sequences and functions. | the complete primary structure of an 80-residue linker polypeptide, lr(c)8.9, from the phycobilisome of the cyanobacterium mastigocladus laminosus was determined as well as the 44 n-terminal residues of the two linker polypeptides lr34.5,pec and lr34.5,pc and the 114 c-terminal residues of lr34.5,pec. a brief description of the structure determination and an extensive discussion of the relationships of these polypeptides have been published recently (füglistaller, p., suter, f. & zuber, h. (1985 ... | 1986 | 3092841 |
| the complete amino-acid sequence of c-phycoerythrin from the cyanobacterium fremyella diplosiphon. | the amino-acid sequences of both subunits of c-phycoerythrin from the cyanobacterium fremyella diplosiphon have been determined. the alpha-subunit contains 164 amino acid residues, two phycoerythrobilin (peb) chromophores and has a molecular mass of 18,368 da (protein: 17,192 da + 2 peb, one peb accounting for 588 da). the beta-subunit consists of 184 residues, three peb chromophores and has a molecular mass of 20,931 da (protein: 19,168 da and 3 peb: 1,764 da). the five peb chromophores (open c ... | 1986 | 3092842 |
| purification and characterization of phosphoenolpyruvate carboxylase from a cyanobacterium. | phosphoenolpyruvate (pep) carboxylase (ec 4.1.1.31) was purified 100-fold from the cyanobacterium coccochloris peniocystis with a yield of 10%. a single isozyme was found at all stages of purification, and activity of other beta-carboxylase enzymes was not detected. the apparent molecular weight of the native enzyme was 560,000. optimal activity was observed at ph 8.0 and 40 degrees c, yielding a vmax of 8.84 mumol/mg of protein per min. the enzyme was not protected from heat inactivation by asp ... | 1986 | 3093461 |