| characterization of dna uptake by the cyanobacterium anacystis nidulans. | the binding and uptake of nick-translated 32p-labeled pbr322 by anacystis nidulans 6301 have been characterized. both processes were considerably enhanced in permeaplasts compared to cells. the breakdown of labeled dna was not correlated with binding or uptake by permeaplasts or cells. uptake of dna by permeaplasts was unaffected by: mg2+ or ca2+, light, or inhibitors of photophosphorylation such as valinomycin or gramicidin d in the presence or absence of nh4cl. atp at 2.5-10 mm inhibited both ... | 1986 | 3093820 |
| transformation in cyanobacteria. | the lack of any known transduction or indigenous conjugation systems has left transformation as the major means for genetic manipulations in cyanobacteria. studies of transformation in cyanobacteria generally have dealt with one of two distinct areas. the first area is genomic transformation where internalized donor dna recombines with chromosomally located genes. chromosomal transformation can be a powerful tool for genetic mapping and mutagenesis. the second area is plasmid transformation wher ... | 1986 | 3095029 |
| biological half-life, organ distribution and excretion of 125-i-labelled toxic peptide from the blue-green alga microcystis aeruginosa. | m. aeruginosa is a bloom-forming cyanobacterium which is common in fresh-water lakes. it contains a potent hepatotoxin which when purified has been shown to be a heptapeptide of molecular weight 1019. the toxin was iodinated with 125i using the lactoperoxidase method, the labelled toxin administered intravenously to adult female rats and the half-life and organ distribution measured. the blood half-life after redistribution into extracellular pools was 42 min. the liver and kidneys showed accumu ... | 1986 | 3096266 |
| 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 |
| 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 |
| asymmetrical core structure in phycobilisomes of the cyanobacterium synechocystis 6701. | the light-harvesting complex of cyanobacteria and red algae, the phycobilisome, has two structural domains, the core and the rods. both contain biliproteins and linker peptides. the core contains the site of attachment to the thylakoid membrane and the energy transfer link between the phycobilisome and chlorophyll. there are also six rod-binding sites in the membrane-distal periphery of the core. the structure of phycobilisomes in the cyanobacterium synechococcus 6301 was studied by glazer, who ... | 1986 | 3102748 |
| 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 |
| effect of chloramphenicol on nitrogen fixation in a cyanobacterium. | | 1986 | 3110113 |
| 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 |
| isolation, sequence analysis, and transcriptional studies of the flavodoxin gene from anacystis nidulans r2. | the nonheme, iron-sulfur protein ferredoxin is the terminal constituent of the photosynthetic electron transport chain. under conditions of iron stress, many cyanobacteria and eucaryotic algae replace ferredoxin with the flavoprotein flavodoxin. the gene for flavodoxin was cloned from the cyanobacterium anacystis nidulans r2 by using three mixed oligonucleotide probes derived from the partial synechococcus sp. strain pcc 6301 amino acid sequence. nucleotide sequence analysis revealed a 513-base- ... | 1988 | 3121586 |
| 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 |
| purification and properties of ferredoxin-nadp+ oxidoreductase from the nitrogen-fixing cyanobacteria anabaena variabilis. | the isolation and characterization of ferredoxin-nadp+ -oxidoreductase from anabaena variabilis, a nitrogen-fixing, filamentous cyanobacterium, is described. purified enzyme was obtained in four steps with a 55% yield and 300-fold purification utilizing chromatographic separations on deae-cellulose and cibacron blue-sepharose columns. the enzyme is quite similar but not identical to the spinach enzyme as judged by isoelectric focusing, molecular weight determination, and amino acid composition. ... | 1988 | 3124746 |
| phosphate transport and arsenate resistance in the cyanobacterium anabaena variabilis. | cells of the cyanobacterium anabaena variabilis starved for phosphate for 3 days took up phosphate at about 100 times the rate of unstarved cells. kinetic data suggested that a new transport system had been induced by starvation for phosphate. the inducible phosphate transport system was quickly repressed by addition of pi. phosphate-starved cells were more sensitive to the toxic effects of arsenate than were unstarved cells, but phosphate could alleviate some of the toxicity. arsenate was a non ... | 1988 | 3125150 |
| complete nucleotide sequence of the red-light specific set of phycocyanin genes from the cyanobacterium calothrix pcc 7601. | | 1988 | 3126486 |
| gtp-binding proteins in a cyanobacterium anabaena cylindrica. | gtp-binding proteins were detected in a crude extract containing membrane components of anabaena cylindrica. the crude extract was treated with 1% lubrol px and was fractionated by gel filtration. the binding of [35s]gtp gamma s to gtp-binding proteins was prevented in the presence of 0.1 mm gtp and in the presence of 0.1 mm atp. six fractions of these gtp-binding proteins, tentatively designated ga1 to ga6, were adp-ribosylated by pertussis toxin. ga3, ga4 and ga5 had km values of 10, 60 and 7 ... | 1988 | 3126734 |
| purification and partial characterization of a calcium-stimulated protease from the cyanobacterium, anabaena variabilis. | a calcium-stimulated protease was purified to apparent homogeneity from the heterocyst-forming cyanobacterium anabaena variabilis atcc 29413. as judged from experiments with inhibitors and chromogenic peptide substrates, the enzyme is a serine protease with a substrate specificity like trypsin. its apparent relative molecular mass is 52,000. calcium depletion inhibits the enzymic activity by 92%. half-maximal activity requires about 0.5 microm free ca2+. the enzyme binds to a hydrophobic column ... | 1988 | 3127208 |
| significance of braided trichomes in the cyanobacterium mastigocladus laminosus. | loops and braids in filaments of the cyanobacterium mastigocladus laminosus were observed. braided filaments were generally in the form of a right-handed helix (87%) but were occasionally observed as left-handed helices (13%). it was demonstrated by time-lapse photomicrography that braids continued to grow as braids and that loops coiled into braids as growth proceeded. measurements of the distance between grooves in 74 braids yielded an average distance of 13 +/- 3 micron, a result which sugges ... | 1988 | 3127375 |
| molecular characterization and evolution of sequences encoding light-harvesting components in the chromatically adapting cyanobacterium fremyella diplosiphon. | the major light-harvesting complex in eukaryotic red algae and prokaryotic cyanobacteria is the phycobilisome, a water-soluble complex located on the outer surface of the photosynthetic membranes and composed of both pigmented phycobiliproteins (85%) and non-pigmented linker (15%) polypeptides. the phycobiliproteins are encoded by a gene family and exhibit varying degrees of sequence homology (25 to 55%). some cyanobacteria can maximize the absorption of prevalent wavelengths of light by adjusti ... | 1988 | 3127591 |
| [hybrid vectors for the cyanobacterium anacystis nidulans r2, containing the plasmid pub110 from staphylococcus aureus]. | the recombinant vector plasmids were constructed having the dna of pub110 plasmid (4,5 kb, kmr) from staphylococcus aureus inserted into the cryptic plasmids pans (8 kb) and panl (48,5 kb) of cyanobacterium anacystis nidulans r2. the hybrid plasmids transform cyanobacterial cells to km-resistance with high efficiency. the plasmid pbs20, containing the complete sequence of pans and pub110 dna, transforms bacillus subtilis rec e4 protoplasts being, however, unstable in bacilli cells and disintegra ... | 1988 | 3128733 |
| toxicity of the cyanobacterium nodularia spumigena mertens. | the bloom forming cyanobacterium (blue-green alga) nodularia spumigena produced a peptide hepatotoxin with an ld50 of 70 micrograms/kg i.p. in mice. the livers of lethally poisoned mice were haemorrhagic and enlarged, the weight doubling to about 10% of total body weight. histologically there was centrilobular to midzonal disruption and lysis of hepatocytes resulting in haemorrhage and formation of blood lakes. death occurred approximately 1 hr after i.p. injection. by 30 min significant increas ... | 1988 | 3129824 |
| preliminary characterization of a toxin isolated from the cyanobacterium nodularia spumigena. | a peptide toxin was isolated from the cyanobacterium nodularia spumigena by high performance liquid chromatography (hplc). the i.p. ld50 of the toxin was 50 micrograms/kg mouse with death within 1-3 hr. the major effects of the toxin were seen in the liver in the form of extensive haemorrhages. amino acid analysis showed the presence of equimolar amounts of glutamic acid, beta-methyl-aspartic acid, and arginine. the toxicological and some of the chemical properties of the isolated toxin were sim ... | 1988 | 3129825 |
| characterization of escherichia coli-anabaena sp. hybrid thioredoxins. | thioredoxin is a small redox protein with an active-site disulfide/dithiol. the protein from escherichia coli has been well characterized. the genes encoding thioredoxin in e. coli and in the filamentous cyanobacterium anabaena pcc 7119 have been cloned and sequenced. anabaena thioredoxin exhibits 50% amino acid identity with the e. coli protein and interacts with e. coli enzymes. the genes encoding anabaena and e. coli thioredoxin were fused via a common restriction site in the nucleotide seque ... | 1988 | 3130096 |
| functional role of vitamin k in photosystem i of the cyanobacterium synechocystis 6803. | the function of vitamin k1 in the primary electron-transfer processes of photosystem i (ps i) was investigated in the cyanobacterium synechocystis 6803. a preparation of purified ps i was found to contain two vitamin k1's per reaction center. one vitamin k1 was removed by extraction with hexane, and further extraction using hexane including 0.3% methanol resulted in a preparation devoid of vitamin k1. the hexane-extracted ps i was functional in the photoreduction of nadp+, but the ps i after ext ... | 1988 | 3130097 |
| targeted mutagenesis of the psbe and psbf genes blocks photosynthetic electron transport: evidence for a functional role of cytochrome b559 in photosystem ii. | the genes encoding the two subunits (alpha and beta) of the cytochrome b559 (cyt b559) protein, psbe and psbf, were cloned from the unicellular, transformable cyanobacterium, synechocystis 6803. cyt b559, an intrinsic membrane protein, is a component of photosystem ii, a membrane-protein complex that catalyzes photosynthetic oxygen evolution. however, the role of cyt b559 in photosynthetic electron transport is yet to be determined. a high degree of homology was found between the cyanobacterial ... | 1988 | 3130246 |
| molecular analysis of a mutant defective in photosynthetic oxygen evolution and isolation of a complementing clone by a novel screening procedure. | photosynthesis-defective mutants of the transformable cyanobacterium synechocystis 6803 have been isolated following nitrosoguanidine mutagenesis. the photosystem ii- phenotype of one of these mutants is shown by dna sequencing to be attributable to a short deletion in psbc, the gene encoding the 44-kd, chlorophyll-binding protein of photosystem ii. although not a component of the reaction center of photosystem ii, the 44-kd protein is none the less shown to be essential in vivo for photosystem ... | 1988 | 3130247 |
| isolation and molecular characterization of the gene encoding allophycocyanin b, a terminal energy acceptor in cyanobacterial phycobilisomes. | phycobilisomes are the major constituents of the light-harvesting apparatus in both cyanobacteria and red algae and consist of a central core with radiating rods. from a genomic library of the cyanobacterium calothrix 7601, a dna fragment encoding allophycocyanin b, one of the two terminal energy acceptors of the core, was isolated and its nucleotide sequence was determined. unlike all the other known genes encoding phycobiliproteins, the allophycocyanin b gene, apcd, is transcribed as a monocis ... | 1988 | 3130540 |
| identification of the region of cyanobacterial plasmid pdu1 necessary for replication in anabaena sp. strain m-131. | shuttle vectors based on plasmid pdu1 from nostoc sp. strain pcc7524 are able to replicate both in escherichia coli and in strains of anabaena and nostoc spp. derivatives partially deleted in the pdu1 portion were tested for their ability to replicate in anabaena sp. strain m-131. plasmid prl6he containing a 1.75-kb hindiii-scai fragment of pdu1 replicated stably in that cyanobacterium and also in anabaena sp. strain pcc7120. plasmid prl6hc, containing an even smaller hpai-scai fragment (1.3 kb) ... | 1988 | 3131190 |
| characterization of phycobilisome glycoproteins in the cyanobacterium anacystis nidulans r2. | concanavalin a-reactive linker and anchor subunits of phycobilisomes from anacystis nidulans r2 (h. c. riethman, t. p. mawhinney, and l. a. sherman, febs lett. 215:209-214, 1987) were purified electrophoretically and analyzed for carbohydrate composition and quantity. different quantities of glucose and n-acetylgalactosamine were found on the concanavalin a-reactive subunits analyzed. proteolytic analysis of the purified subunits suggested that small regions of the 33- and 27-kilodalton linker p ... | 1988 | 3131300 |
| long-chain alkanediols: biological markers for cyanobacterial contributions to sediments. | one significant family of sedimentary lipids of widespread occurrence are series of c28-c32 alkanediols and hydroxyketones. the recognition of the same series of alkanediols as major lipid components of a field population of the cyanobacterium aphanizomenon flos-aquae leads us to propose that these lipids are markers for cyanobacterial inputs to sediments. the frequency of occurrence of the alkanediols in sedimentary environments supports the recent finding that cyanobacteria are major contribut ... | 1988 | 3131613 |
| impact of chromium and lead on nostoc muscorum: regulation of toxicity by ascorbic acid, glutathione, and sulfur-containing amino acids. | nostoc muscorum can be protected from cr and pb toxicity by supplementing 10 micrograms/ml of ascorbic acid, reduced glutathione, and 5 micrograms/ml of sulfur-containing amino acids (l-methionine and l-cysteine). appreciable stimulation of different parameters of nostoc by ascorbic acid and glutathione was noticed in the untreated culture. these substances when used in the presence of metals were found to restore ionic loss, growth, 14co2 uptake, heterocyst production, and nitrogenase activity ... | 1988 | 3132363 |
| cloning of nifhd from nostoc commune utex 584 and of a flanking region homologous to part of the azotobacter vinelandii nifu gene. | the heterocystous cyanobacterium nostoc commune utex 584 contains two nifh-like sequences (nifh1 and nifh2) in addition to nifhd. a region of dna 1 kilobase upstream from the 5' end of nifh showed considerable sequence similarity to part of the published nifu sequences of azotobacter vinelandii and klebsiella pneumoniae. | 1988 | 3133363 |
| analysis of anatoxin-a by gc/ecd. | anatoxin-a (antx-a), a potent cholinergic alkaloid produced by some toxigenic strains of the cyanobacterium anabaena flos-aquae, has been responsible for death of livestock, pets, and wildlife. an increase in the frequency of cyanobacterial blooms in fresh waters of temperate north america has produced a concomitant increase in the threat posed by toxic strains of some of these microorganisms. presently, a mouse bioassay is the general procedure used for testing the toxicity of a bloom-approxima ... | 1988 | 3133523 |
| glycinebetaine as an osmoregulant and compatible solute in the marine cyanobacterium spirulina subsalsa. | glycinebetaine was found to be the major organic substrate accumulating under hypersaline growth conditions in the halotolerant cyanobacterium spirulina subsalsa. in addition to its proposed role as osmolite, glycinebetaine is shown to specifically protect enzymatic activity. glucose-6-phosphate dehydrogenase from s. subsalsa retained full activity in the presence of nacl at concentrations as high as 1.5 m, provided that comparable concentrations of glycinebetaine were also present in the reacti ... | 1988 | 3134857 |
| oral toxicity of a bloom of the cyanobacterium microcystis aeruginosa administered to mice over periods up to 1 year. | cyanobacterial blooms in lakes have been reported causing livestock deaths and liver injury to human populations. in this study bloom material consisting of microcystis aeruginosa was collected from a farm water storage after the death of sheep drinking from it. the cyanobacterial cells were lysed and a cell-free extract was provided to mice at a series of dilutions as their only source of drinking water. mice of both sexes, with controls, were killed at intervals up to 1 yr of administration. a ... | 1988 | 3135416 |
| detection of chlorophyllide in chlorophyll-free plasma membrane preparations from anacystis nidulans. | plasma and thylakoid membranes were isolated and purified from the cyanobacterium anacystis nidulans. spectrophotometric examination of acetone extracts gave major absorption bands resulting from carotenoids and chlorophyll a in plasma and thylakoid membranes, respectively. only a very small absorption peak at 663 nm was detected in acetone extracts of plasma membranes which, in contrast to the corresponding peak from thylakoid membranes, could not be extracted into n-hexane; methanol, on the ot ... | 1988 | 3136769 |
| rna polymerase subunit homology among cyanobacteria, other eubacteria and archaebacteria. | rna polymerase purified from vegetative cells of the cyanobacterium anabaena sp. strain pcc 7120 contains a dissociable sigma factor and a core of five subunits: the beta', beta, and two alpha subunits characteristic of all eubacteria and an additional 66,000-molecular-weight polypeptide called gamma. fifteen of fifteen strains of unicellular and filamentous cyanobacteria tested contained a serologically related gamma protein. antiserum to gamma reacted with escherichia coli beta' and the a subu ... | 1988 | 3137214 |
| primary- and secondary-structural analysis of a unique prokaryotic metallothionein from a synechococcus sp. cyanobacterium. | biochemical and physiological studies of synechococcus cyanobacteria have indicated the presence of a low-mr heavy-metal-binding protein with marked similarity to eukaryotic metallothioneins (mts). we report here the characterization of a synechococcus prokaryotic mt isolated by gel-permeation and reverse-phase chromatography. the large number of variants of this molecule found during chromatographic separation could not be attributed to the presence of major isoproteins as assessed by amino aci ... | 1988 | 3137921 |
| properties and structure of the soluble ferredoxin from synechococcus 6301 (anacystis nidulans). relationship to gene sequences. | photoautotrophic cultures of the unicellular cyanobacterium synechococcus 6301 (anacystis nidulans) possessed a single [2fe-2s] ferredoxin with a midpoint redox potential of -385 mv. determination of the amino acid sequence of the ferredoxin showed that it consisted of 98 residues, with methionine and tryptophan both absent, and with only the four cysteine residues that are required to co-ordinate the iron-sulphur cluster. comparisons with other ferredoxin sequences showed that most resemblance ... | 1988 | 3137930 |
| low-potential iron-sulfur centers in photosystem i: an x-ray absorption spectroscopy study. | we have measured the x-ray absorption spectra of fe in photosystem i (ps i) preparations from spinach and a thermophilic cyanobacterium, synechococcus sp., to characterize structures of the fe complexes that function as electron acceptors in ps i. these acceptors include centers a and b, which are probably typical [4fe-4s] ferredoxins, and x. the structure of x is not known, but its electron paramagnetic resonance (epr) spectrum has generated the suggestions that it is either a [2fe-2s] or [4fe- ... | 1988 | 3137969 |
| purification and characterization of an iron stress-induced chlorophyll-protein from the cyanobacterium anacystis nidulans r2. | an anacystis nidulans r2 chlorophyll-protein associated with photosystem ii in iron-stressed cells (pakrasi, h.b., riethmann, h.c. and sherman, l.a. (1985) proc. natl. acad. sci. usa 82, 6903-6907) has been biochemically purified and characterized. anion exchange chromatography of dodecyl-beta-d-maltoside-solubilized membranes from iron-deficient cells was used to recover this chlorophyll-protein (termed cpvi-4) in high yield and in a relatively native state. cpvi-4 has a room temperature absorp ... | 1988 | 3137971 |
| nucleotide sequence and transcript analysis of three photosystem ii genes from the cyanobacterium synechococcus sp. pcc7942. | the genome of the cyanobacterium synechococcus sp. pcc7942 contains two genes encoding the d2 polypeptide of photosystem ii (psii), which are designated here as psbdi and psbdii. the psbdi gene, like the psbd gene of plant chloroplasts, is cotranscribed with and overlaps the open reading frame of the psbc gene, encoding the psii protein cp43. the psbdii gene is not linked to psbc, and appears to be transcribed as a monocistronic message. the two psbd genes encode identical polypeptides of 352 am ... | 1988 | 3138165 |
| [expression of the nif and ntr genes of klebsiella pneumoniae in rhodobacter sphaeroides cells]. | the genes glna, ntr, nif or their promoters from klebsiella pneumoniae cloned on the vectors, based on the plasmid rsf1010, were introduced into rhodobacter sphaeroides cells. it was found that k. pneumoniae genes glna, nifb, nife, nifl and nifh are not expressed in r. sphaeroides. neither was the glna gene from cyanobacterium anabaena 7120 expressed in r. sphaeroides. no functional activity of k. pneumoniae product of ntra gene which is expressed from its own promoter, and the product of the ge ... | 1988 | 3139488 |
| cloning, nucleotide sequence, and mutagenesis of a gene (irpa) involved in iron-deficient growth of the cyanobacterium synechococcus sp. strain pcc7942. | we describe the cloning and sequencing of a gene from the cyanobacterium synechococcus sp. strain pcc7942, designated irpa (iron-regulated protein a), that encodes for a protein involved in iron acquisition or storage. polyclonal antibodies raised against proteins which accumulate during iron-deficient growth were used as probes to isolate immunopositive clones from a lambda gt11 genomic expression library. the clone, designated lambda gtan26, carried a 1.7-kilobase (kb) chromosomal dna insert a ... | 1988 | 3139627 |
| induction, isolation, and some properties of the nadph-dependent glutamate dehydrogenase from the nonheterocystous cyanobacterium phormidium laminosum. | the level of the nadph-dependent glutamate dehydrogenase activity (ec 1.4.1.4) from nitrate-grown cells of the thermophilic non-n2-fixing cyanobacterium phormidium laminosum oh-1-p.cl1 could be significantly enhanced by the presence of ammonium or nitrite, as well as by l-methionine-dl-sulfoximine and other sources of organic nitrogen (l-glu, l-gln, and methylamine). the enzyme was purified more than 4,400-fold by ultracentrifugation, ion-exchange chromatography, and affinity chromatography, and ... | 1988 | 3139639 |
| toxicity to mice and sheep of a bloom of the cyanobacterium (blue-green alga) anabaena circinalis. | a bloom of anabaena circinalis shown to be lethal to mice (i.p. ld50 17.0 +/- 0.6 mg/kg) was tested for lethal potency when given orally to mice and intraruminally and intraperitoneally to sheep. the lethal oral dose in mice was at least 170 times the parenteral dose. the bloom was lethal when given i.p. to sheep but lethality was not observed when given intraruminally in doses up to 1710 mg/kg, equivalent to drinking 8.5 litres of thick algal bloom, a volume far in excess of that likely to be c ... | 1988 | 3140424 |
| blood pressure and hepatocellular effects of the cyclic heptapeptide toxin produced by the freshwater cyanobacterium (blue-green alga) microcystis aeruginosa strain pcc-7820. | laboratory rats and mice were used to investigate the hepatotoxicity caused by the cyclic heptapeptide (mol. wt 994) termed microcystin-lr. microcystin-lr (also known as cyanoginosin-lr) is produced by the freshwater cyanobacterium (blue-green alga) m. aeruginosa strain pcc-7820. in time course histopathology studies with mice significant liver damage, with an absence of pulmonary emboli, were observed after 15 min. pulmonary emboli did not appear until 1 hr. in rats, significant liver damage an ... | 1988 | 3140425 |
| characterization of a cyanobacterial iron stress-induced gene similar to psbc. | recently we have reported that the flavodoxin gene from the cyanobacterium anacystis nidulans r2 is transcribed as part of an iron stress-induced operon containing multiple mrna species (d. e. laudenbach, m. e. reith, and n. a. straus, j. bacteriol. 170: 258-265, 1988). here we report that nucleotide sequence analyses of dna located immediately upstream of the flavodoxin gene revealed an open reading frame of 1,026 bases (designated isia; iron stress inducible) with a deduced amino acid sequence ... | 1988 | 3141374 |
| deletion of a 55-kilobase-pair dna element from the chromosome during heterocyst differentiation of anabaena sp. strain pcc 7120. | the filamentous cyanobacterium anabaena sp. strain pcc 7120 produces terminally differentiated heterocysts in response to a lack of combined nitrogen. heterocysts are found approximately every 10th cell along the filament and are morphologically and biochemically specialized for nitrogen fixation. at least two dna rearrangements occur during heterocyst differentiation in anabaena sp. strain pcc 7120, both the result of developmentally regulated site-specific recombination. the first is an 11-kil ... | 1988 | 3141375 |
| molecular cloning and sequencing of the psad gene encoding subunit ii of photosystem i from the cyanobacterium, synechocystis sp. pcc 6803. | photosystem i reaction center was isolated from the cyanobacterium, synechocystis sp. pcc 6803, in a form which contains seven different polypeptide subunits. one of the subunits, with a molecular mass of about 16 kda, was isolated, and protein sequence information was obtained for the amino terminus and several tryptic peptides. oligonucleotide probes, corresponding to these sequences, were used to probe a genomic library, and the gene, designated psad, encoding subunit ii was cloned and sequen ... | 1988 | 3141423 |
| antibiotic effects on growth and heterocyst differentiation of the cyanobacterium nostoc muscorum. | in a medium free of combined nitrogen, 1.0-6.0 micrograms/ml chloramphenicol gradually decreased the growth of the nitrogen-fixing cyanobacterium nostoc muscorum; at 2.0 micrograms/ml the culture appeared yellowish, heterocyst frequency was not evident up to 3.0 micrograms/ml, whereas 4.0 micrograms/ml suppressed heterocyst differentiation. lower concentrations (0.0125-0.75 microgram/ml) of rifampicin suppressed the growth but had no significant effect on heterocyst frequency in liquid medium, w ... | 1988 | 3142201 |
| toxicity and partial structure of a hepatotoxic peptide produced by the cyanobacterium nodularia spumigena mertens emend. l575 from new zealand. | a clonal isolate, termed l575, of the filamentous brackish-water cyanobacterium nodularia spumigena mertens emend. was found to produce a potent hepatotoxic peptide (50% lethal intraperitoneal dose for the mouse, 60 micrograms/kg) with chemical and toxicological properties similar to those of the hepatotoxic heptapeptides produced by other freshwater planktonic cyanobacteria. the isolate was made from a water sample collected in lake ellesmere, new zealand, in 1980. the toxin, isolated and purif ... | 1988 | 3142356 |
| acyl-acyl-carrier protein: lysomonogalactosyldiacylglycerol acyltransferase from the cyanobacterium anabaena variabilis. | membranes isolated from the cyanobacterium, anabaena variabilis, and washed free of soluble endogenous constituents, were capable of catalyzing the direct transfer of the acyl group from acyl-acyl-carrier protein to an endogenous lysomonogalactosyldiacylglycerol to form monogalactosyldiacylglycerol. other glycolipids including monoglucosyldiacylglycerol and digalactosyldiacylglycerol were not products of this reaction. the transfer was not dependent on any added cofactors. palmitoyl-, stearoyl- ... | 1988 | 3143419 |
| the peptide toxin of the cyanobacterium microcystis aeruginosa pcc 7941. isolation and analysis by nuclear magnetic resonance and fast atom bombardment mass spectroscopy. | toxin was obtained from the cyanobacterium microcystis aeruginosa pcc7941 by extracting freeze-dried cells with water-saturated, acidified n-butanol, diethyl ether-water distribution, reversed-phase thin-layer chromatography and silica high-performance liquid chromatography (hplc). two toxic peptide fractions resulted from hplc. one of these fractions was analyzed by uv and nmr spectroscopy, amino acid analysis and fast atom bombardment mass spectroscopy. the following amino acid analysis and fa ... | 1988 | 3147986 |
| weigle-reactivation in a cyanobacterium (synechococcus pcc7934) is induced by uv but not by mitomycin-c or nalidixic acid. | | 1988 | 3148138 |
| partial structural determination of hepatotoxic peptides from microcystis aeruginosa (cyanobacterium) collected in ponds of central china. | waterbloom samples of the colonial cyanobacterium microcystis aeruginosa, collected in fish ponds at the hydrobiological institute, wuhan, people's republic of china, were hepatotoxic to mice. lyophilized cells had an ld50 (i.p. mouse; 40 mg/kg) and signs of poisoning similar to that reported for other cyanobacterial hepatotoxic peptides. two toxins, with an ld50 (i.p. mouse) of 40 and 150 micrograms/kg, were isolated using gel filtration and high performance liquid chromatography. the amino aci ... | 1988 | 3149051 |
| directed mutagenesis indicates that the donor to p+680 in photosystem ii is tyrosine-161 of the d1 polypeptide. | photosystem ii contains two redox-active tyrosines. one of these, yz, reduces the reaction center chlorophyll, p680, and transfers the oxidizing equivalent to the oxygen-evolving complex. the second, yd, has a long-lived free radical state of unknown function. we recently established that yd is tyr-160 of the d2 polypeptide by site-directed mutagenesis of a psbd gene in the unicellular cyanobacterium synechocystis 6803 [debus, r. j., barry, b. a., babcock, g. t., & mcintosh, l. (1988) proc. natl ... | 1988 | 3149511 |
| polypeptide patterns obtained by polyacrylamide gel electrophoresis of thylakoid membranes isolated from light and dark grown strains of chlorogloea fritschii. | sodium dodecyl sulphate-polyacrylamide gel electrophoresis has been used to determine the difference between thylakoid polypeptide patterns of light and dark grown strains of the cyanobacterium chlorogloea fritschii. there were only 2 prominent bands present in the dark grown strains, polypeptide mr50,000 and polypeptide mr90,000, also five fainter bands in the mr range 45,000-66,200 corresponding to photosystem one, compared with the 32 bands present in the light grown strains. there was no obv ... | 1988 | 3149577 |
| the use of carotenoids and oxonol vi as probes for membrane potential in proteoliposomes. | carotenoids present in lipids extracted from the cyanobacterium synechococcus 6716 indicate trans-membrane potential in proteoliposomes reconstituted from these lipids and the atpase complex isolated from the same organism. a carotenoid absorbance band shift to a longer wavelength is obtained with valinomycin-induced potassium ion diffusion potentials, irrespective of the polarity of the potassium gradient. in contrast to this, the (externally added) probe oxonol vi only shows an absorbance band ... | 1985 | 3157600 |
| comparison of effects of anatoxin-a(s) and paraoxon, physostigmine and pyridostigmine on mouse brain cholinesterase activity. | anatoxin-a(s), an alkaloid neurotoxin from the freshwater cyanobacterium, anabaena flos-aquae nrc-525-17, was compared to paraoxon, physostigmine and pyridostigmine for effects on brain cholinesterase after i.p. injection into balb/c mice. the duration of clinical signs in mice injected with anatoxin-a(s) persisted longer than in mice given the carbamates and was comparable with that of paraoxon. anatoxin-a(s) did not inhibit brain cholinesterase activity suggesting that this toxin is unable to ... | 1988 | 3188065 |
| pathophysiology of cyanoginosin-lr: in vivo and in vitro studies. | cyanoginosin-lr, one of the group of virulent cyclic heptapeptide toxins (cyanoginosins) isolated from some strains of the cyanobacterium, microcystis aeruginosa, kills mice within 1-2 hr after iv or ip injection. although the liver is a target organ of the toxin, the rapidity of lethality is incompatible with metabolic death from failure of hepatocellular function. however, disintegration of sinusoidal endothelium causes massive intrahepatic hemorrhage. the loss of the structural integrity of h ... | 1988 | 3194914 |
| 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 |
| effect of heat shock on protein synthesis in the cyanobacterium synechococcus sp. strain pcc 6301. | the response to heat shock at 47 degrees c was examined in the cyanobacterium (blue-green alga) synechococcus sp. strain pcc 6301. on heat shock, the growth of the cells decreased and they preferentially synthesized a limited number of polypeptides. the rate of synthesis of these proteins increased markedly in the early period of temperature shift up and gradually decreased afterwards. among the proteins greatly affected by temperature shift up were those with apparent molecular weights of 91,00 ... | 1985 | 3918983 |
| effect of nitrogen starvation on the morphology and ultrastructure of the cyanobacterium mastigocladus laminosus. | the effects of nitrogen starvation on the morphology and ultrastructure of the branching, filamentous cyanobacterium mastigocladus laminosus were examined with light and electron microscopy. the internal ultrastructural characteristics of vegetative cells changed markedly during nitrogen starvation. carboxysomes were degraded, while polyphosphate bodies and lipid bodies accumulated. the ultrastructure of mature heterocysts was also affected by nitrogen starvation; their intracytoplasmic membrane ... | 1985 | 3918986 |
| factors affecting the dissociation and reconstitution of ribulose-1,5-bisphosphate carboxylase/oxygenase from aphanothece halophytica. | factors affecting the mutual interaction between the catalytic core [octamer of large subunit (a)] and the small subunit (b) comprising ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) from the superhalophilic cyanobacterium, aphanothece halophytica, were investigated. the enzyme molecule dissociated into the catalytic core highly depleted of subunit b and the monomeric form of subunit b during density gradient centrifugation (15 h, 4 degrees c) in a sucrose solution of low ionic streng ... | 1985 | 3919647 |
| rearrangement of nitrogen fixation genes during heterocyst differentiation in the cyanobacterium anabaena. | nitrogen fixation by the cyanobacterium anabaena is carried out in heterocysts, specialized, non-dividing cells which differentiate under conditions of ammonia or nitrate deprivation. in anabaena, heterocyst differentiation is accompanied by rearrangement of some nitrogen fixation genes. a site-specific recombination between an 11 base-pair direct repeat sequence flanking the nifk and nifd genes removes 11 kilobases of intervening dna, resulting in juxtaposition of the two genes and an alteratio ... | 1985 | 3920531 |
| guidance of cytophaga sp. strain u67 gliding on the sheaths of oscillatoria princeps. | individual cells of cytophaga sp. strain u67 glided in helical patterns on the surface of sheaths deposited by the cyanobacterium oscillatoria princeps. possible bases for the helical substructure of the sheath are discussed. | 1985 | 3921528 |
| catalytic properties of a hybrid between cyanobacterial large subunits and higher plant small subunits of ribulose bisphosphate carboxylase-oxygenase. | the small subunits of spinach ribulosebisphosphate carboxylase-oxygenase were isolated by mild acid precipitation of the hexadecameric holoenzyme. about one-third of the small subunits remained in the supernatant while the remainder, and all of the large subunits, were precipitated and irreversibly denatured. the spinach small subunits were able to reassemble with the large subunit octamer of ribulosebisphosphate carboxylase-oxygenase from the cyanobacterium, synechococcus acmm 323, prepared as ... | 1985 | 3921534 |