Publications

polysaccharide covalently linked to the peptidoglycan of the cyanobacterium synechocystis sp. strain pcc6714.	a polysaccharide was found to be covalently linked to the peptidoglycan of the unicellular cyanobacterium synechocystis sp. strain pcc6714 via phosphodiester bonds. it could be cleaved from the peptidoglycan-polysaccharide (pg-ps) complex by hydrofluoric acid (hf) treatment in the cold (48% hf, 0 degrees c, 48 h) yielding a pure, hf-insoluble peptidoglycan fraction and an hf-soluble polysaccharide fraction. the pg-ps complex was isolated from the triton x-100-insoluble cell wall fraction by hot ...	1986	3096958
isolation and nucleotide sequence analysis of the ferredoxin i gene from the cyanobacterium anacystis nidulans r2.	two mixed oligonucleotide probes derived from conserved regions of the synechocystis sp. strain pcc 6714 ferredoxin amino acid sequence were utilized to isolate an anacystis nidulans r2 clone containing the ferredoxin i gene. nucleotide sequence analysis revealed a 297-base-pair (bp) open reading frame with a deduced amino acid sequence having high homology to other cyanobacterial ferredoxins. assuming proteolytic cleavage of the initial methionine residue, the molecular weight of the mature a. ...	1986	3096975
expression of a family of psba genes encoding a photosystem ii polypeptide in the cyanobacterium anacystis nidulans r2.	the genome of the cyanobacterium anacystis nidulans r2 contains three genes (psba) for the qb protein of photosystem ii. this protein is essential for oxygenic photosynthetic electron tansport, and is the target for several herbicides which act by binding directly to the photosynthetic apparatus. transcripts from the three anacystis psba genes are present in wild-type cells at different steady-state levels. the nucleotide sequences of two of the genes, psbaii and psbaiii, predict a protein havin ...	1986	3098559
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
estimation of gene expression in heterocysts of anabaena variabilis by using dna-rna hybridization.	in the filamentous cyanobacterium anabaena variabilis, specialized cells called heterocysts occur in a regular pattern along the filament and are the sites of nitrogen fixation. we used two different types of dna-excess rna hybridization techniques to estimate the number of genes expressed in recently differentiated, mature heterocysts. in the first, rna and dna were incubated in a phosphate buffer at 60 degrees c, and the hybrids were separated from the unhybridized material by hydroxylapatite ...	1986	2427500
polysome turnover in immobilized cells of nostoc commune (cyanobacteria) exposed to water stress.	water stress induced changes in the polysome content of immobilized cells of the desiccation-tolerant cyanobacterium nostoc commune utex 584. cells maintained an intact protein synthesis complex during 2 h of drying at -99.5 mpa. polysomes were not recovered from cells subjected to extended periods of desiccation.	1986	2430937
isolation and sequence of the gene for ferredoxin i from the cyanobacterium anabaena sp. strain pcc 7120.	the structural gene for ferredoxin i, petf, from the cyanobacterium anabaena sp. strain pcc 7120 has been isolated from a recombinant lambda library. mixtures of tetradecanucleotides and heptadecanucleotides, each containing all possible dna sequences corresponding to two separate regions of the ferredoxin amino acid sequence, were synthesized and used as hybridization probes to identify a genomic clone containing the coding sequence for the petf gene. the sequence of the entire petf coding regi ...	1986	2430949
green light induces transcription of the phycoerythrin operon in the cyanobacterium calothrix 7601.	phycobilisomes, the major light-harvesting complexes of cyanobacteria are multimolecular structures made up of chromophoric proteins called phycobiliproteins and non chromophoric linker polypeptides. we report here the isolation and nucleotide sequence of the genes, cpea and cpeb, which in calothrix pcc 7601 encode the alpha and beta subunits of phycoerythrin, one of the major phycobiliproteins. in calothrix pcc 7601, modulation of the polypeptide composition of the phycobilisomes occurs in resp ...	1986	2431391
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
enrichment of a 50-kilodalton polypeptide in a photosystem ii-phycobilisome particle from porphyridium cruentum.	a 50-kda polypeptide was obtained from photosynthetically active phycobilisome-photosystem ii preparations from the red alga porphyridium cruentum after removal of phycobiliproteins. removal of phycobiliproteins caused destabilization of the structure of the phycobilisome-photosystem ii preparations and was accompanied by a decline in photosystem ii activity (oxygen-evolution and dichlorophenol-indophenol (dpip) reduction). the treatments in increasing relative effectiveness were: addition of ed ...	1986	3535676
post-translational methylation of asparaginyl residues. identification of beta-71 gamma-n-methylasparagine in allophycocyanin.	a novel post-translationally modified residue, gamma-n-methylasparagine, was detected in the beta subunit of anabaena variabilis allophycocyanin. structure determination was accomplished by isolating a decapeptide, ap-beta (63-72) shown to have the following structure: ser-asp-ile-thr-arg-pro-gly-gly- asn[n-ch3]-homoserine lactone fast atom bombardment-mass spectrometry established that the residue corresponding to position 71 in the protein (delange, r. j., williams, l. c., and glazer, a. n. (1 ...	1986	3782095
carbon-13 nmr studies of salt shock-induced carbohydrate turnover in the marine cyanobacterium agmenellum quadruplicatum.	carbon turnover in response to abrupt changes in salinity, including the mobilization of glycogen for use in osmoregulation was studied with pulse-chase strategies utilizing nuclear magnetic resonance (nmr)-silent and nmr-detectable 12c and 13c isotopes, respectively. growth of agmenellum quadruplicatum in 30%-enriched 13c bicarbonate provided sufficient nmr-detectability of intracellular organic osmoregulants for these studies. a comparison of nmr spectra of intact cells and their ethanol ext ...	1986	11539092
association of a new type of gliding, filamentous, purple phototrophic bacterium inside bundles of microcoleus chthonoplastes in hypersaline cyanobacterial mats.	an unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium microcoleus chthonoplastes in a hypersaline pond at guerrero negro, baja california sur, mexico, and in solar lake, sinai, egypt. this organism is a gliding, segmented trichome, 0.8-0.9 micrometer wide. it contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, sim ...	1987	11542090
paleobiology of distinctive benthic microfossils from the upper proterozoic limestone-dolomite "series," central east greenland.	populations of polybessurus bipartitus fairchild ex green et al., a large morphologically distinctive microfossil, occur in silicified carbonates of the upper proterozoic (700-800 ma) limestone-dolomite "series," central east greenland. large populations of well-preserved individuals permit reconstruction of p. bipartitus as a coccoidal unicell that "jetted" upward from the sediment by the highly unidirectional secretion of extracellular mucopolysaccharide envelopes. reproduction by baeocyte f ...	1987	11542125
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
effects of light deprivation on rna synthesis, accumulation of guanosine 3'(2')-diphosphate 5'-diphosphate, and protein synthesis in heat-shocked synechococcus sp. strain pcc 6301, a cyanobacterium.	the rate of total rna synthesis, the extent of guanosine 3'(2')-diphosphate 5'-diphosphate (ppgpp) accumulation, and the pattern of protein synthesis were studied in light-deprived and heat-shocked synechococcus sp. strain pcc 6301 cells. there was an inverse correlation between the rate of total rna synthesis and the pool of ppgpp, except immediately after a temperature shift up, when a parallel increase in the rate of rna synthesis and accumulation of ppgpp was observed. the inverse correlatio ...	1987	2433265
phycobilisome-associated glycoproteins in the cyanobacterium anacystis nidulans r 2.	four phycobilisome-associated proteins were found to be specifically reactive with the lectin concanavalin a after subunits of isolated anacystis nidulans r 2 phycobilisomes were separated on polyacrylamide gels and transferred onto nitrocellulose. the concanavalin a-reactive phycobilisome components have proposed functions related to the orientation, assembly, and membrane attachment of the phycobilisome. chemical analysis of the total isolated phycobilisome material indicated the presence of g ...	1987	2438157
transcriptional analysis of the cyanobacterial gvpabc operon in differentiated cells: occurrence of an antisense rna complementary to three overlapping transcripts.	cyanobacteria are photosynthetic prokaryotes able to colonize almost all kinds of ecosystems. some of them exhibit differentiation processes and/or may establish tight symbiotic associations. upon changes in the environmental conditions, the cyanobacterium calothrix 7601 differentiates hormogonia which are short filaments of small cells resulting from cellular division and fragmentation of the long filaments of vegetative cells. in calothrix, hormogonia are characterized by their gliding motilit ...	1987	2450053
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
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
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
mutations that affect structure and assembly of light-harvesting proteins in the cyanobacterium synechocystis sp. strain 6701.	the unicellular cyanobacterium synechocystis sp. strain 6701 was mutagenized with uv irradiation and screened for pigment changes that indicated genetic lesions involving the light-harvesting proteins of the phycobilisome. a previous examination of the pigment mutant uv16 showed an assembly defect in the phycocyanin component of the phycobilisome. mutagenesis of uv16 produced an additional double mutant, uv16-40, with decreased phycoerythrin content. phycocyanin and phycoerythrin were isolated f ...	1987	3098729
characterization of the motile hormogonia of mastigocladus laminosus.	the cyanobacterium mastigocladus laminosus produces motile hormogonia which move by gliding motility. these hormogonia were characterized in terms of their morphology, state of differentiation of the cells, optimal temperature for production and motility, minimal nutritional requirements to sustain motility, liberation of the hormogonium from its parental trichome, average surface velocity, and maximal concentration of agar through which the hormogonium may move. we found that an average hormogo ...	1987	3098731
organization of genes for ribosomal proteins s7 and s12, elongation factors ef-tu and ef-g in the cyanobacterium spirulina platensis.	the gene encoding ribosomal proteins s12 and probably s7 as well as protein synthesis elongation factors tu (ef-tu) and g (ef-g) of spirulina platensis have been identified and cloned. gene expression was determined for ribosomal protein s12 by genetic complementation of the appropriate escherichia coli mutant, whereas for the ef-tu gene it was determined by production of the protein in e. coli minicells. on the basis of these experiments we suggest the following gene order in the s. platensis c ...	1987	3101737
nitrogen starvation mediated by dl-7-azatryptophan in the cyanobacterium anabaena sp. strain ca.	the addition of dl-7-azatryptophan (azat), a tryptophan analog, to continuous cultures of anabaena sp. strain ca grown with 10 mm nitrate as the nitrogen source resulted in the differentiation of heterocysts. analysis of the intracellular amino acid pools of anabaena sp. strain ca after the addition of azat showed a marked decline in the intracellular glutamate pool and a slight increase in the levels of glutamine. the in vitro activity of glutamate synthase, the second enzyme involved in primar ...	1987	3102456
the phycobiliprotein beta 16.2 of the allophycocyanin core from the cyanobacterium mastigocladus laminosus. characterization and complete amino-acid sequence.	the minor phycobiliprotein beta 16.2 was isolated from the apc-core of phycobilisomes from the cyanobacterium mastigocladus laminosus. its complete amino-acid sequence and some spectral characteristics are presented. beta 16.2 consists of 169 amino acids and its molecular mass is 19,390 da. a phycocyanobilin chromophore is covalently bound to a cysteine at position 84 as in all other phycobiliproteins. the first 138 amino acids are highly homologous to the n-terminal part of beta ap (62.5%), whe ...	1987	3103645
purification procedure for peptide toxins from the cyanobacterium microcystis aeruginosa involving high-performance thin-layer chromatography.		1987	3104380
nucleotide sequence of phycocyanin beta-subunit gene of cyanobacterium anacystis nidulans strain r2.		1987	3104880
functional expression of plastid allophycocyanin genes in a cyanobacterium.	in cyanophora paradoxa, the allophycocyanin apoprotein subunits, alpha and beta, are encoded in the cyanelle (plastid) genome. these genes were transferred to the cyanobacterium synechococcus sp. pcc 7002 on a plasmid replicon. phycobilisomes isolated from transformed cyanobacteria were found to contain c. paradoxa allophycocyanin subunits. thus, these plastid genes are expressed in the cyanobacterium as polypeptides which become linked to a chromophore and are incorporated into the light-harves ...	1987	3106320
alteration of the fe protein of nitrogenase by oxygen in the cyanobacterium anabaena sp. strain ca.	changes in protein composition were noted when heterocysts of anabaena sp. strain ca were isolated from filaments grown in 1% co2-99% n2 and subsequently exposed to oxygen. immunospecific western blot analysis showed that the fe protein of nitrogenase is altered. in cells grown under microaerobic conditions, the fe protein was found in a form with an apparent molecular weight of 30,000. exposure to oxygen caused a shift in the migration of this polypeptide to a position corresponding to an appar ...	1987	3108236
isolation and characterization of light-regulated phycobilisome linker polypeptide genes and their transcription as a polycistronic mrna.	several cyanobacteria adjust both the phycobiliprotein and linker protein composition of the phycobilisome, a light-harvesting complex in cyanobacteria and some eucaryotic algae, to maximize absorption of prevalent wavelengths of light. this process is called complementary chromatic adaptation. we sequenced the amino terminus of a linker polypeptide which is associated with phycocyanin and accumulates to high levels during growth of the cyanobacterium fremyella diplosiphon in red light. a mixed ...	1987	3108238
molecular cloning and characterization of the reca gene from the cyanobacterium synechococcus sp. strain pcc 7002.	the reca gene of synechococcus sp. strain pcc 7002 was detected and cloned from a lambda gtwes genomic library by heterologous hybridization by using a gene-internal fragment of the escherichia coli reca gene as the probe. the gene encodes a 38-kilodalton polypeptide which is antigenically related to the reca protein of e. coli. the nucleotide sequence of a portion of the gene was determined. the translation of this region was 55% homologous to the e. coli protein; allowances for conservative am ...	1987	3108239
distribution of microcystis aeruginosa peptide toxin and interactions with hepatic microsomes in mice.	purified 14c-labelled peptide toxin from the cyanobacterium microcystis aeruginosa was administered intraperitoneally to mice and the distribution of label determined between the major organs. seventy per cent of the label was localized in the liver after 1 min.; this value increasing to almost 90 per cent after 3 hours. label associated with the lungs and other individual organs varied between 10 and 1 per cent of the 14c recovered throughout. three microsomal enzyme inducers, beta-naphthoflavo ...	1987	3108872
ultrastructural changes in the mouse liver induced by hepatotoxin from the freshwater cyanobacterium microcystis aeruginosa strain 7820.	the time-course of ultrastructural changes was studied in mouse liver hepatocytes after i.p. injection of lethal (100 micrograms/kg) and sublethal (10 micrograms/kg) doses of the heptapeptide hepatotoxin from microcystis aeruginosa strain 7820, a freshwater blue-green alga (cyanobacterium). at both dose levels the hepatocytes show progressive intracellular changes over time periods of 10, 20, 30, and 60 min. the changes resulting from a lethal dose were more prominent and rapid compared to those ...	1987	3109075
cloning and light regulation of expression of the phycocyanin operon of the cyanobacterium anabaena.	the biliprotein phycocyanin (pc) is a major constituent of the light-harvesting apparatus of cyanobacteria and red algae. a dna fragment encoding the beta and alpha subunits of pc was isolated from a genomic library of the cyanobacterium anabaena 7120 dna. the single-copy pc genes are part of a larger operon which consists of five open reading frames (orfs) encoding, in order, the beta and alpha subunits of pc, two linker polypeptides associated with pc in phycobilisome rods, and a fifth orf, wh ...	1987	3109890
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
allophycocyanin complexes of the phycobilisome from mastigocladus laminosus. influence of the linker polypeptide l8.9c on the spectral properties of the phycobiliprotein subunits.	the following phycobiliproteins and complexes of the allophycocyanin core were isolated from phycobilisomes of the thermophilic cyanobacterium mastigocladus laminosus: alpha ap, beta ap, (alpha ap beta ap), (alpha ap beta ap)3, (alpha ap beta ap)3l8.9c, (alpha apb alpha ap2 beta ap3)l8.9c. the six proteins and complexes were characterised spectroscopically with respect to absorption, oscillator strength, extinction coefficient, fluorescence emission, relative quantum yield, fluorescence emission ...	1987	3111493
a developmentally regulated gvpabc operon is involved in the formation of gas vesicles in the cyanobacterium calothrix 7601.	in the filamentous cyanobacterium calothrix pcc7601, gas-vesicle (gv) formation is restricted to specialized filaments, called hormogonia. the differentiation of these cells is controlled by environmental factors, such as light intensity and/or wavelength. the structural gene (gvpa) encoding a gv protein in this cyanobacterium has been previously cloned and sequenced. two other genes, gvpb and gvpc have been found in the sequence downstream from gvpa. the gvpb gene corresponds to a second copy o ...	1987	3111941
sodium-coupled motility in a swimming cyanobacterium.	the energetics of motility in synechococcus strain wh8113 were studied to understand the unique nonflagellar swimming of this cyanobacterium. there was a specific sodium requirement for motility such that cells were immotile below 10 mm external sodium and cell speed increased with increasing sodium levels above 10 mm to a maximum of about 15 microns/s at 150 to 250 mm sodium. the sodium motive force increased similarly with increasing external sodium from -120 to -165 mv, but other energetic pa ...	1987	3112121
anomalous behaviour of forward and perpendicular light scattering of a cyanobacterium owing to intracellular gas vacuoles.	extinction, absorption, and forward and perpendicular light scatter of the blue-green alga microcystis aeruginosa with different amounts of intracellular gas vacuoles were determined. the amount of gas vacuoles in the cells was controlled by application of pressure. the presence of the gas vacuoles caused a tenfold increase in perpendicular light scatter, and a fivefold decrease in forward light scatter as measured by flow cytometry. chlorophyll fluorescence showed a 16% decrease. the presence o ...	1987	3113896
regulated nitrate transport in the cyanobacterium anacystis nidulans.	intracellular accumulation of nitrate, indicative of the operation of an active nitrate transport system, has been measured in intact cells of the cyanobacterium anacystis nidulans. the ability of the cells to accumulate nitrate was effectively hindered by either ammonium addition or selective inhibition of co2 fixation by dl-glyceraldehyde, with the effect of either compound being prevented by previously blocking ammonium assimilation. the results support the contention that nitrate utilization ...	1987	3114240
effect of light quality, anaerobiosis and glucose on nitrogen-fixation by the rice field cyanobacterium aulosira fertilissima ghose.	anaerobiosis enhanced the nitrogenase activity of the rice field alga aulosira fertilissima both in light and dark. the activity was maximum in white light, lesser in red, blue and green light and least in the dark. glucose stimulated the activity both in light and dark.	1987	3115052
cell selective cytotoxicity of a peptide toxin from the cyanobacterium microcystis aeruginosa.	the effects of a cyclic peptide toxin, isolated from the cyanobacterium microcystis aeruginosa, on cell morphology and ion transport in human erythrocytes, isolated rat hepatocytes and mouse fibroblasts (3t3) were studied. neither in erythrocytes nor in fibroblasts did the toxin cause morphological alterations. in hepatocytes the toxin induced marked morphological alterations at a concentration of about 50 nm. in erythrocytes and fibroblasts no effects on ion transport were observed. in hepatocy ...	1987	3115307
genetic analysis of amino acid transport in the facultatively heterotrophic cyanobacterium synechocystis sp. strain 6803.	the existence of active transport systems (permeases) operating on amino acids in the photoautotrophic cyanobacterium synechocystis sp. strain 6803 was demonstrated by following the initial rates of uptake with 14c-labeled amino acids, measuring the intracellular pools of amino acids, and isolating mutants resistant to toxic amino acids. one class of mutants (pfa1) corresponds to a regulatory defect in the biosynthesis of the aromatic amino acids, but two other classes (can1 and aza1) are defect ...	1987	3115962
blue-green algae (microcystis aeruginosa) hepatotoxicosis in dairy cows.	twenty cows from a dairy herd consisting of 60 healthy, lactating holsteins developed clinical signs of anorexia, mental derangement, dehydration, recumbency, and ruminal atony after ingesting water containing blue-green algae. of the 20 cows, 9 died. the algal bloom, which developed in a stagnant pond during hot, dry weather, was identified as the cyanobacterium microcystis aeruginosa, a potentially hepatotoxic algae. one week after the onset of toxicosis, affected cows seemed healthy, although ...	1987	3116892
purification and characterization of rna polymerase from the cyanobacterium anabaena 7120.	a procedure for the purification of rna polymerase from vegetative cells of the filamentous cyanobacterium anabaena 7120 is described. polyethyleneimine precipitation followed by gel filtration and affinity chromatography steps results in greater than 99% purification with 46% yield. the enzyme has a novel core component of mr = 66,000, designated gamma, in addition to the typical prokaryotic beta'beta alpha 2 core enzyme. the sigma subunit has been identified by reconstitution of specific trans ...	1987	3117788
crosslinking of phycobiliproteins from the cyanobacterium mastigocladus laminosus with bis-imidates: localization of an intrasubunit and an intersubunit crosslink in c-phycocyanin.	the light-harvesting pigment-protein complexes allophycocyanin (ap), c-phycocyanin (pc) and phycoerythrocyanin (pec) of the cyanobacterium mastigocladus laminosus consist of alpha- and beta-subunits containing about 170 amino-acid residues each. these two subunits form an alpha,beta-monomer, three of which build up a disc-shaped trimer. in this study these phycobiliproteins were crosslinked with bis-imidates. various spacer lengths of the reagent and various aggregation states of the phycobilipr ...	1987	3118901
effects of the peptide toxin from microcystis aeruginosa on intracellular calcium, ph and membrane integrity in mammalian cells.	extracts of water blooms of the toxic cyanobacterium microcystis aeruginosa showed a range of toxicities not related to their ability to lyse mammalian red cells. the hplc-purified heptapeptide toxin (mol. wt. 1035) from microcystis did not lyse red cells at up to 500-fold higher concentrations than that required to kill mice. this toxin (ld50 110 micrograms/kg for male mice) was used to investigate in vitro effects on isolated thymocytes, hepatocytes, mammary alveolar cells, and cultured swiss ...	1987	3119237
physiological conditions for nitrogen fixation in a unicellular marine cyanobacterium, synechococcus sp. strain sf1.	a marine, unicellular, nitrogen-fixing cyanobacterium was isolated from the blades of a brown alga, sargassum fluitans. this unicellular cyanobacterium, identified as synechococcus sp. strain sf1, is capable of photoautotrophic growth with bicarbonate as the sole carbon source and dinitrogen as the sole nitrogen source. among the organic carbon compounds tested, glucose and sucrose supported growth. of the nitrogen compounds tested, with bicarbonate serving as the carbon source, both ammonia and ...	1987	3119563
nucleotide sequence of the gene from the cyanobacterium anacystis nidulans r2 encoding the mn-stabilizing protein involved in photosystem ii water oxidation.	the gene for the mn-stabilizing protein (msp; the so-called extrinsic 33-kda protein) that is involved in photosystem ii water oxidation was cloned and sequenced from the genome of the cyanobacterium anacystis nidulans r2. the gene (here designated woxa) was shown to be present in a single copy. the deduced amino acid sequence indicated that the translation product consisted of 277 amino acid residues with a mr of 29,306. the comparison of the sequence with that of mature msp from spinach chloro ...	1987	3120187
photoreduction of qa, qb, and cytochrome b-559 in an oxygen-evolving photosystem ii preparation from the thermophilic cyanobacterium synechococcus sp.	light-induced absorption changes in an oxygen-evolving photosystem ii (ps ii) preparation from the thermophilic cyanobacterium synechococcus sp. were analyzed using continuous illumination which caused the reduction of both qa (first stable quinone electron acceptor) and qb (second quinone electron acceptor of photosystem ii). in this photosystem ii preparation in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu) the amount of qa was estimated to be 1 per 42 chlorophylls. in the abs ...	1987	3120642
nucleotide sequence of a member of the psba multigene family from the unicellular cyanobacterium synechocystis 6803.		1987	3122184
isolation and localization of n4-methylasparagine in phycobiliproteins from the cyanobacterium mastigocladus laminosus.	the occurrence of post-translationally methylated asparagine residues in beta ap from anabaena variabilis, synechococcus pcc 6301 and porphyridium cruentum has recently been reported (klotz, a.v., leary, j.a. & glazer, a.n. (1986) j. biol. chem. 261, 15891-15894). we reinvestigated the amino-acid compositions of all phycobiliproteins from mastigocladus laminosus. during total hydrolysis of beta ap, beta 16.2 and beta pc one mol methylamine per mol protein was released. these proteins were chemic ...	1987	3122783
liquid chromatographic determination of the cyanoginosins, toxins produced by the cyanobacterium microcystis aeruginosa.		1987	3123509
anatoxin-a(s), an anticholinesterase from the cyanobacterium anabaena flos-aquae nrc-525-17.	anatoxin a(s) [antx-a(s)] given intraperitoneally to sprague-dawley rats at different doses (0.1-1.0 mg/kg) caused signs of severe cholinergic overstimulation. assays of rat blood acetylcholinesterase (ache) revealed a dose-dependent inhibition. the in vitro inhibition of electric eel acetylcholinesterase (ache, e.c. 3.1.1.7) and horse serum butyrylcholinesterase (buche, e.c. 3.1.1.8) by antx-a(s) was time- and concentration-dependent. the inhibition of electric eel ache follows first order kine ...	1987	3124299
injury to hepatocytes induced by a peptide toxin from the cyanobacterium microcystis aeruginosa.	the freshwater, bloom forming cyanobacterium (blue-green alga) microcystis aeruginosa produces a peptide hepatotoxin which causes death accompanied by liver necrosis. we show here that the time and dose-dependent blebbing of isolated hepatocytes is accompanied by the activation of phosphorylase a, with no changes in cyclic amp levels, and by glutathione (acid-soluble thiols) depletion. these results suggest that the disruption of cytoskeletal structures is accompanied by disturbances in cellular ...	1987	3124300
photosynthetic assimilation of no(3) by intact cells of the cyanobacterium anacystis nidulans: influence of no(3) and nh(4) assimilation on co(2) fixation.	illuminated suspensions of anacystis nidulans, supplied with saturating concentrations of co(2) evolved o(2) at a greater rate when nitrate was simultaneously present. the extent of the stimulation of noncyclic electron flow induced by nitrate was dependent on light intensity, being maximal under light saturating conditions. accordingly, nitrate depressed the rate of co(2) fixation at limiting but not at saturating light, this depression reflecting the competition between both processes for assi ...	1987	16665204
the susceptibility of photosynthesis to photoinhibition and the capacity of recovery in high and low light grown cyanobacteria, anacystis nidulans.	the susceptibility of photosynthesis to photoinhibition and the rate of its recovery were studied in the cyanobacterium anacystis nidulans grown at a low (10 micromoles per square meter per second) and a high (120 micromoles per square meter per second) photosynthetically active radiation. the rate of light limited photosynthetic o(2) evolution was measured to determine levels of photoinhibition and rates of recovery. studies of photoinhibition and recovery with and without the translation inhib ...	1987	16665264
na-stimulation of photosynthesis in the cyanobacterium synechococcus utex 625 grown on high levels of inorganic carbon.	photosynthesis of washed cells of synechococcus utex 625 grown on 5% co(2) was markedly stimulated (647 +/- 50%) at ph 8.0 by the addition of low concentrations of nacl (concentration required for half-maximal response, k((1/2),) = 18 micromolar). studies with kcl and na(2)so(4) showed that the stimulation was due to na(+). photosynthesis at ph 6.1 was only slightly stimulated by na(+). the response of photosynthesis at ph 8.0 to [na(+)] was strongly sigmoidal for dissolved inorganic carbon ([di ...	1987	16665383
evidence for na-independent hco(3) uptake by the cyanobacterium synechococcus leopoliensis.	at low levels of dissolved inorganic carbon (dic) and alkaline ph the rate of photosynthesis by air-grown cells of synechococcus leopoliensis (utex 625) was enhanced 7- to 10-fold by 20 millimolar na(+). the rate of photosynthesis greatly exceeded the co(2) supply rate and indicated that hco(3) (-) was taken up by a na(+)-dependent mechanism. in contrast, photosynthesis by synechococcus grown in standing culture proceeded rapidly in the absence of na(+) and exceeded the co(2) supply rate by 8 to ...	1987	16665385
isolation and characterization of a carotenoid-associated thylakoid protein from the cyanobacterium anacystis nidulans r2.	a carotenoid-associated membrane protein was isolated from anacystis nidulans r2 thylakoids. sodium pyrophosphate and sodium bromide washed thylakoids were solubilized with the nonionic detergents dodecyl-beta-d-maltoside and octyl-beta-d-glucopyranoside, and these detergent extracts were fractionated on a sucrose density gradient. a yellow fraction from the sucrose gradient was further purified by anion-exchange and organomercuric-affinity column chromatography to yield a fraction virtually fre ...	1987	16665493
contiguous organization of nitrogenase genes in a heterocystous cyanobacterium.	the organization of the three structural nitrogen fixation (nif) genes that encode nitrogenase (nif k and nif d) and nitrogenase reductase (nif h) have been examined in a number of cyanobacteria. hybridization of anabaena 7120 nif gene probes to restriction endonuclease-digested genomic dna has shown (a) that cyanobacteria incapable of n(2) fixation have no regions of dna with significant homology to the three nif probes, (b) that pseudanabaena sp., a nonheterocystous cyanobacterium, has a conti ...	1987	16665666
carbonic anhydrase and the uptake of inorganic carbon by synechococcus sp. (utex-2380).	we report the changes in the concentrations and (18)o contents of extracellular co(2) and hco(3) (-) in suspensions of synechococcus sp. (utex 2380) using membrane inlet mass spectrometry. this marine cyanobacterium is known to have an active uptake mechanism for inorganic carbon. measuring (18)o exchange between co(2) and water, we have found the intracellular carbonic anhydrase activity to be equivalent to 20 times the uncatalyzed co(2) hydration rate in different samples of cells that were gr ...	1987	16665686
construction of an obligate photoheterotrophic mutant of the cyanobacterium synechocystis 6803 : inactivation of the psba gene family.	psba in synechocystis 6803 was found to belong to a small multigene family with three copies. the psba gene family was inactivated in vitro by insertation of bacterial drug resistance markers. inactivation of all three genes resulted in a transformant that is unable to grow photosynthetically but can be cultured photoheterotrophically. this mutant lacks oxygen evolving capacity but retains photosystem i activity. room temperature measurements of chlorophyll a fluorescence induction demonstrated ...	1987	16665796
crystallization of the photosystem i reaction centre.	the reaction centre of the photosynthetic membrane complex photosystem i (psi) from the thermophilic cyanobacterium phormidium laminosum was found to crystallize under a range of conditions. the crystallization method, which can occur in the presence of larger detergent molecules than those used previously for the crystallization of membrane proteins, is presented in this report. several crystal forms have been observed, and some of these show birefringence and linear dichroism. optical measurem ...	1987	16453774
oxygen-poor microzones as potential sites of microbial n(2) fixation in nitrogen-depleted aerobic marine waters.	the nitrogen-deficient coastal waters of north carolina contain suspended bacteria potentially able to fix n(2). bioassays aimed at identifying environmental factors controlling the development and proliferation of n(2) fixation showed that dissolved organic carbon (as simple sugars and sugar alcohols) and particulate organic carbon (derived from spartina alterniflora) additions elicited and enhanced n(2) fixation (nitrogenase activity) in these waters. nitrogenase activity occurred in samples c ...	1987	16347337
relationship between sodium influx and salt tolerance of nitrogen-fixing cyanobacteria.	the relationship between sodium uptake and cyanobacterial salt (nacl) tolerance has been examined in two filamentous, heterocystous, nitrogen-fixing species of anabaena. during diazotrophic growth at neutral ph of the growth medium, anabaena sp. strain l-31, a freshwater strain, showed threefold higher uptake of na than anabaena torulosa, a brackish-water strain, and was considerably less salt tolerant (50% lethal dose of nacl, 55 mm) than the latter (50% lethal dose of nacl, 170 mm). alkaline p ...	1987	16347419
diel vertical movements of the cyanobacterium oscillatoria terebriformis in a sulfide-rich hot spring microbial mat.	oscillatoria terebriformis, a thermophilic cyanobacterium, carried out a diel vertical movement pattern in hunter's hot springs, oreg. throughout most daylight hours, populations of o. terebriformis covered the surface of microbial mats in the hot spring outflows below an upper temperature limit of 54 degrees c. upon darkness trichomes moved downward by gliding motility into the substrate to a depth of 0.5 to 1.0 mm, where the population remained until dawn. at dawn the population rapidly return ...	1987	16347435
enhanced survival of the cyanobacterium oscillatoria terebriformis in darkness under anaerobic conditions.	oscillatoria terebriformis, a thermophilic cyanobacterium, maintained viability in darkness under anaerobic conditions by fermenting exogenous glucose or fructose to lactic acid. the time period of survival was greatly extended when the environmental redox potential was lowered by the addition of sodium thioglycolate or titanium(iii) citrate. when exposed to aerobic conditions in darkness, many trichomes underwent lysis in 6 h, and death of all cells occurred in 2 to 3 days. the endogenous aerob ...	1987	16347436
the impact of atrazine on lake periphyton communities, including carbon uptake dynamics using track autoradiography.	chlorophyll a, freshweight biomass, ash-free dry weight, cell numbers, species richness, community carbon uptake and species-specific carbon uptake were used to monitor the impact of atrazine (2 chloro-4-ethylamino-6-isopropylamino-s-triazine) on an in situ, enclosed periphyton community. atrazine concentrations ranging from 0.08 to 1.56 mg litre(-1) were used during the 2 years of study. in both 1982 and 1983, there was a shift from a chlorophyte- to a diatom-dominated community. in 1982 the cy ...	1987	15092733
factors affecting the photoproduction of ammonia from dinitrogen and water by the cyanobacterium anabaena sp. strain atcc 33047.	synthesis of ammonia from dinitrogen and water by suspensions of anabaena sp. strain atcc 33047 treated with the glutamine synthetase inhibitor l-methionine-d,l-sulfoximine is strictly dependent on light. under otherwise optimal conditions, the yield of ammonia production is influenced by irradiance, as well as by the density, depth, and turbulence of the cell suspension. the interaction among these factors seems to determine the actual amount of light available to each single cell or filament i ...	1987	18576487
investigation of the structure of trimeric and monomeric photosystem i reaction centre complexes.	electron microscopy of monomeric and trimeric forms of the reaction centre of photosystem i from the thermophilic cyanobacterium phormidium laminosum has allowed the construction of a three-dimensional model describing the shape of the complex. the trimeric form of the photosystem i reaction centre complex was found to have a very regular shape corresponding to a rounded equilateral triangle with edges 18 nm long and a thickness of 6 nm. a distinctive chiral arrangement of the three reaction cen ...	1988	16453855
aluminum effects on uptake and metabolism of phosphorus by the cyanobacterium anabaena cylindrica.	aluminum severely affects the growth of the cyanobacterium anabaena cylindrica and induces symptoms indicating phosphorus starvation. preor post-treating the cells with high (90 micromolar) phosphorus reduces the toxicity of aluminum compared to cells receiving a lower orthophosphate concentration. in this study aluminum (ranging from 9 to 36 micromolar) and phosphorus concentrations were chosen so that the precipitation of insoluble aipo(4) never exceeded 10% of the total phosphate concentratio ...	1988	16665849
chlorophyll a fluorescence yield as a monitor of both active co(2) and hco(3) transport by the cyanobacterium synechococcus utex 625.	simultaneous measurements have been made of inorganic carbon accumulation (by mass spectrometry) and chlorophyll a fluorescence yield of the cyanobacterium synechococcus utex 625. the accumulation of inorganic carbon by the cells was accompanied by a substantial quenching of chlorophyll a fluorescence. the quenching occurred even when co(2) fixation was inhibited by iodoacetamide and whether the accumulation of inorganic carbon resulted from either active co(2) or hco(3) (-) transport. measureme ...	1988	16665965
active transport of co(2) by the cyanobacterium synechococcus utex 625 : measurement by mass spectrometry.	mass spectrometry has been used to confirm the presence of an active transport system for co(2) in synechococcus utex 625. cells were incubated at ph 8.0 in 100 micromolar khco(3) in the absence of na(+) (to prevent hco(3) (-) transport). upon illumination the cells rapidly removed almost all the free co(2) from the medium. addition of carbonic anhydrase revealed that the co(2) depletion resulted from a selective uptake of co(2), rather than a total uptake of all inorganic carbon species. co(2) ...	1988	16665969
light-induced proton release by the cyanobacterium anabaena variabilis: dependence on co(2) and na.	light-induced acidification by the cyanobacterium anabaena variabilis is biphasic (a fast phase i and slow phase ii) and shown to be sodium-dependent with an optimum concentration of 40 to 60 millimolar na(+). cells grown under low co(2) concentrations at ph 9 (i.e. mainly hco(3) (-) present in the medium) exhibited the slow phase ii of proton efflux only, while cells grown under low co(2) concentrations at ph 6.3 (i.e. co(2) and hco(3) (-) present) exhibited both phases. light-induced proton re ...	1988	16665985
identification and purification of a derepressible alkaline phosphatase from anacystis nidulans r2.	we have examined the increase in alkaline phosphatase activity in the cyanobacterium anacystis nidulans r2 upon phosphate deprivation. much of the activity is released into the medium when a. nidulans is osmotically shocked, indicating that the enzyme is located either in the periplasmic space or is loosely bound to the cell wall. the polypeptide associated with phosphatase activity has been identified as a single species of m(r) 160,000. several lines of evidence demonstrate that this polypepti ...	1988	16666051
role of photosynthetic reactions in the activity of carbonic anhydrase in synechococcus sp. (utex 2380) in the light : inhibitor studies using the o-exchange in c/o-labeled bicarbonate.	the role of the photosystems in the exchange of (18)o between species of inorganic carbon and water was studied in suspensions of the cyanobacterium synechococcus sp. (utex 2380) using membrane-inlet mass spectrometry. this (18)o exchange is caused by the hydration-dehydration cycle of co(2) and is catalyzed by carbonic anhydrase. we observed the complex (18)o exchange kinetics including dark-light-dark transients in suspensions of whole cells and found these to be identical to the (18)o exchang ...	1988	16666052
simultaneous transport of co(2) and hco(3) by the cyanobacterium synechococcus utex 625.	a mass spectrometer was used to simultaneously follow the time course of photosynthetic o(2) evolution and co(2) depletion of the medium by cells of the cyanobacterium synechococcus leopoliensis utex 625. analysis of the data indicated that both co(2) and hco(3) (-) were simultaneously and continuously transported by the cells as a source of substrate for photosynthesis. initiation of hco(3) (-) transport by na(+) addition had no effect on ongoing co(2) transport. this result is interpreted to i ...	1988	16666182
active transport of inorganic carbon increases the rate of o(2) photoreduction by the cyanobacterium synechococcus utex 625.	chlorophyll a fluorescence of synechococcus utex 625 was quenched during the transport of inorganic carbon, even when co(2) fixation was inhibited by iodoacetamide. measurements with a pulse modulation fluorometer showed that at least 75% of the quenching was due to oxidation of q(a), the primary acceptor of photosystem ii. mass spectrometry revealed that transport of inorganic carbon increased the rate of o(2) photoreduction. hence, o(2) could serve as an electron acceptor to allow oxidation of ...	1988	16666280
immunological characterization of iron-regulated membrane proteins in the cyanobacterium anacystis nidulans r2.	antibodies cross-reactive with specific membrane proteins were used to investigate membrane development in anacystis nidulans r2 during recovery from iron stress. polyclonal antibodies prepared using the iron-regulated chlorophyll (chl)-protein cpvi-4 (hb pakrasi, hc riethman, la sherman 1985 proc natl acad sci usa 82: 6903-6907) as antigen were characterized and used to identify three iron stress-induced polypeptides of 36, 35, and 34 kilodaltons on immunoblots of polyacrylamide gels. the 34 ki ...	1988	16666334
characterization of the na-requirement in cyanobacterial photosynthesis.	the na(+) requirement for photosynthesis and its relationship to dissolved inorganic carbon (dic) concentration and li(+) concentration was examined in air-grown cells of the cyanobacterium synechococcus leopoliensis utex 625 at ph 8. analysis of the rate of photosynthesis (o(2) evolution) as a function of na(+) concentration, at fixed dic concentration, revealed two distinct regions to the response curve, for which half-saturation values for na(+) (k((1/2))[na(+)]) were calculated. the value of ...	1988	16666379
a new uv-a/b protecting pigment in the terrestrial cyanobacterium nostoc commune.	a new ultraviolet (uv)-a/b absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium nostoc commune is described. the pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar uv radiation but only in low concentrations in laboratory cultures illuminated by artificial light without uv. its experimental induction by uv as well as its capacity to efficiently protect nostoc against uv radiation is reported.	1988	16666420
changes in accumulation and synthesis of transcripts encoding phycobilisome components during acclimation of fremyella diplosiphon to different light qualities.	we have used gene-specific dna fragments as hybridization probes to quantitate the levels of transcripts encoding several phycobilisome polypeptides in the cyanobacterium fremyella diplosiphon in response to changes in the light environment. while the levels of transcripts encoding allophycocyanin, the core linker polypeptide, and the constitutive phycocyanin subunits are similar in f. diplosiphon grown either in red or green light, the levels of other transcripts change dramatically. transcript ...	1988	16666425
co(2) fixation rate and rubisco content increase in the halotolerant cyanobacterium, aphanothece halophytica, grown in high salinities.	the growth of the halotolerant cyanobacterium aphanothece halophytica, previously adapted to 0.5 molar nacl, was optimal when nacl concentration in culture medium was in the range 0.5 to 1.0 molar. the growth was delayed at either too low or too high salinities with lag time of ca. 0.5 day in 0.25 molar nacl and ca. 2 days in 2 molar nacl under the experimental conditions. however, the growth rates at the logarithmic phase were similar in the culture media containing nacl in the range 0.25 to 2. ...	1988	16666431