| ultrastructural and chemical assessment of poly-beta-hydroxybutyric acid in the marine cyanobacterium trichodesmium thiebautii. | we report here on the occurrence and quantities of poly-beta-hydroxybutyric acid (phb) in natural populations of the marine cyanobacterium trichodesmium thiebautii. a diurnal variation in the shape and size of phb granules and in phb content was observed. the highest phb levels (2.3 +/- 0.8 mg g-1 dry wt) were recorded in the early morning and the values decreased thereafter with a minimum at night (1.6 +/- 0.9 mg g-1 dry wt). our data suggest that phb is a prominent cell constituent in t. thieb ... | 1992 | 1325936 |
| copper-mediated regulation of cytochrome c553 and plastocyanin in the cyanobacterium synechocystis 6803. | in certain cyanobacteria and algae, cytochrome c553 or plastocyanin can serve to carry electrons from the cytochrome bf complex to photosystem i. the availability of copper in the growth medium regulates which protein is present. to investigate copper induced control of gene expression we isolated these proteins from the cyanobacterium synechocystis 6803. using immunodetection and optical spectroscopy, the steady state levels of cytochrome c553 and plastocyanin were measured in cells grown at di ... | 1992 | 1326543 |
| involvement of arginine residues in the allosteric activation and inhibition of synechocystis pcc 6803 adpglucose pyrophosphorylase. | adpglucose pyrophosphorylase (ec 2.7.7.27) from the cyanobacterium synechocystis pcc 6803 was desensitized to the effects of allosteric ligands by treatment with the arginine reagent, phenylglyoxal. enzyme modification by phenylglyoxal resulted in inactivation when the enzyme was assayed under 3p-glycerate-activated conditions. there was little loss of the catalytic activity assayed in the absence of activator. pi, 3p-glycerate, and pyridoxal-p were able to protect the enzyme from inactivation, ... | 1992 | 1326983 |
| growth response of the nitrogen-fixing cyanobacterium westiellopsis prolifica janet to fertilizer factory effluents. | | 1992 | 1327314 |
| f0-f1-type atpase is not light-regulated in vivo in the cyanobacterium synechocystis pcc 6803. | | 1992 | 1330768 |
| protein-tyrosyl radical interactions in photosystem ii studied by electron spin resonance and electron nuclear double resonance spectroscopy: comparison with ribonucleotide reductase and in vitro tyrosine. | the stable tyrosine radical in photosystem ii, yd*, has been studied by esr and endor spectroscopies to obtain proton hyperfine coupling constants from which the electron spin density distribution can be deduced. simulations of six previously published esr spectra of psii (one at q band; five at x band, of which two were after specific deuteration and two others were of oriented membranes) can be achieved by using a single set of magnetic parameters that includes anisotropic proton hyperfine ten ... | 1992 | 1332777 |
| a unique ascorbate peroxidase active component in the cyanobacterium synechococcus pcc 7942 (r2). | ascorbate peroxidase active component (apac) was purified and characterized in synechococcus pcc 9742 (r2) cells. apac was isolated from freshly harvested cells, by ion exchange chromatography on deae cellulose, ultrafiltration through a 3000 dalton cut off filter and high pressure liquid chromatography through a reversed phase c-18 column. apac was found to be extremely stable to harsh treatments of boiling water for 30 min, acidification to ph 2.0 and proteolytic digestion. a close correlation ... | 1992 | 1332915 |
| nucleotide sequence of the synechococcus sp. pcc7942 heme gene encoding the homologue of mammalian uroporphyrinogen decarboxylase. | we have determined the complete nucleotide sequence of a synechococcus sp. pcc7942 gene encoding the homologue of mammalian uroporphyrinogen decarboxylase (urod). the gene, designated heme, encoded a polypeptide of 354 amino acids with a molecular weight of 39,283. the primary sequences of the polypeptide encoded by heme and human and rat urod had 32.5% identical amino acid residues. no invariant cysteine residues were found, despite the fact that urod isolated from different sources has been sh ... | 1992 | 1339332 |
| cloning, sequencing, and molecular analysis of the dnak locus from bacillus subtilis. | by using an internal part of the dnak gene from bacillus megaterium as a probe, a 5.2-kb hindiii fragment of chromosomal dna of bacillus subtilis was cloned. downstream sequences were isolated by in vivo chromosome walking. sequencing of 5,085 bp revealed four open reading frames in the order orf39-grpe-dnak-dnaj. orf39 encodes a 39-kda polypeptide of unknown biological function with no noticeable homology to any other protein within the data bases. alignment of the grpe protein with those of th ... | 1992 | 1339421 |
| [effects of nitrogen nutritional deficiency on the distribution of particular lipids in a eutrophic lake milieu]. | the seasonal distribution of particulate lipids coupled with n-nutrient availability was studied in eutrophic lake aydat (massif central, france). the concentrations of lipids ranged between 196.9 and 2971.5 micrograms.l-1 (mean +/- s.d. = 1090.1 +/- 705.5 micrograms.l-1. lipids were abundant in summer and fall when nitrates were insufficient reflecting thus an orientation of cell metabolism towards an accumulation of storage products. in such conditions, the heterocystous cyanobacteria were fou ... | 1992 | 1341139 |
| release of heptapeptide toxin (microcystin) during the decomposition process of microcystis aeruginosa. | the decomposition process of toxic blue-green alga (cyanobacteria), microcystis aeruginosa, under dark and aerobic condition was investigated in relation to the change of the amounts of heptapeptide toxins (microcystins yr and lr) by two experiments: one with microcystis cells and the other with two purified microcystins. in the experiment with microcystis cells, an increase of heterotrophic bacteria observed from the beginning of the experiment, was followed by decomposition of the algal cells ... | 1992 | 1344901 |
| regulation of anabaena sp. strain pcc 7120 glutamine synthetase activity in a synechocystis sp. strain pcc 6803 derivative strain bearing the anabaena glna gene and a mutated host glna gene. | the glna gene from synechocystis sp. strain pcc 6803 was cloned by hybridization with the glna gene from anabaena sp. strain pcc 7120, and a deletion-insertion mutation of the synechocystis gene was generated in vitro. a strain derived from synechocystis sp. strain pcc 6803 which contained integrated into the chromosome, in addition to its own glna gene, the anabaena glna gene was constructed. from that strain, a synechocystis sp. glna mutant could be obtained by transformation with the inactiva ... | 1992 | 1345914 |
| heat shock protein synthesis of the cyanobacterium synechocystis pcc 6803: purification of the groel-related chaperonin. | synechocystis pcc 6803 cells could be induced to synthesize four major hsps with apparent molecular sizes of 70, 64, 15 and 14 kda. heat stress at 42.5 degrees c appeared to be the optimum temperature for hsp formation in cells grown at 30 degrees c. the relative rate of synthesis of hsp70 and hsp15 reached a maximum at 30 min after the temperature shift-up whereas the capability of cells to accumulate hsp64 and hsp14 continued through 2 h. the two most abundant hsps, hsp70 and hsp64, were recog ... | 1992 | 1346251 |
| purification and determination of glutamine synthetase by high-performance immunoaffinity chromatography. | high-performance immunoaffinity chromatography (hpiac) with anti-glutamine synthetase polyclonal antibodies bound to epoxy-activated silica was used to purify and determine this enzyme from the cyanobacterium synechocystis. a single-step hpiac procedure with cell-free extracts yielded electroporetically homogeneous glutamine synthetase. in the determination of glutamine synthetase by hpiac a linear response in the range 10-60 micrograms of enzyme was observed. recoveries of 70% of the loaded enz ... | 1992 | 1347294 |
| of cabbages and chlorine: cholera in peru. | the low case fatality rates (1%) from the 1991 cholera epidemic in peru was more a result of including diarrheas of a less virulent etiology than that of cholera. in fact, a study during the early phases of the cholera epidemic in trujillo, peru revealed that only 79% of suspected cholera cases were infected with vibrio cholera 01. further other people contended that the government of peru did not chlorinate many water supplies because studies by the us environmental protection agency suggeste ... | 1992 | 1351603 |
| alga or bacterium? | | 1992 | 1353242 |
| traveller's diarrhoea associated with cyanobacterium-like bodies. | | 1992 | 1354313 |
| amplification and rearrangement of a prokaryotic metallothionein locus smt in synechococcus pcc 6301 selected for tolerance to cadmium. | metal-tolerant cyanobacteria have been isolated from metal-polluted aquatic environments and also selected in culture, but no genes which confer metal tolerance have been described. to investigate the possibility that amplification of a prokaryotic metallothionein gene (smta), or rearrangement of the smt locus, could be involved in the development of cd tolerance in synechococcus pcc 6301, cd-tolerant lines were selected by stepwise adaptation of a synechococcus culture. an increase in smta gene ... | 1992 | 1354365 |
| chaperones classified. | | 1992 | 1357556 |
| travellers' diarrhoea associated with cyanobacterium-like bodies. | | 1992 | 1359227 |
| glutamine synthetase and nitrogen cycling in colonies of the marine diazotrophic cyanobacteria trichodesmium spp. | we examined freshly collected samples of the colonial planktonic cyanobacterium trichodesmium thiebautii to determine the pathways of recently fixed n within and among trichomes. high concentrations of glutamate and glutamine were found in colonies. glutamate and glutamine uptake rates and concentrations in cells were low in the early morning and increased in the late morning to reach maxima near midday; then uptake and concentration again fell to low values. this pattern followed that previousl ... | 1992 | 1359837 |
| molecular characterization of the gene encoding glutamine synthetase in the cyanobacterium calothrix sp. pcc 7601. | in order to study the regulation of the synthesis of glutamine synthetase in response to changes in environmental parameters (light and nitrogen sources), we have cloned and sequenced the glna gene from the filamentous cyanobacterium calothrix pcc 7601. this gene consists of 472 codons and encodes a polypeptide of m(r) 52,290 highly homologous to that from anabaena pcc 7120, but more distant from those identified from other procaryotes. the relative abundance of the two glna transcripts (1.6 and ... | 1992 | 1362348 |
| biosynthesis of the tropane-related cyanobacterial toxin anatoxin-a: role of ornithine decarboxylase. | a study was made of the biosynthesis by anabaena flos-aquae of the tropane-related alkaloid anatoxin-a. evidence is presented that the toxin arises from ornithine via putrescine (1,4-diaminobutane) and that ornithine decarboxylase (ec 4.1.1.17) is involved. an ornithine decarboxylase preparation, with optimal activity at ph 8, was obtained from anabaena flos-aquae and partially purified by gel-filtration chromatography on deae-cellulose. one major and one minor peak of enzymic activity were obta ... | 1990 | 1367427 |
| use of a rapid bioluminescence assay for detecting cyanobacterial microcystin toxicity. | the recent rise in the awareness of the occurrence of toxic cyanobacterial blooms in aquatic environments, with associated human health problems and animal deaths, has increased the need for rapid, reliable and sensitive methods of determining cyanobacterial toxicity. a luminescent bacterial toxicity test was assessed as a complement to the established mouse bioassay. seventeen samples including pure cyanobacterial microcystin-lr hepatotoxin, laboratory isolates and natural blooms of cyanobacter ... | 1990 | 1367480 |
| elucidation and optimization of the medium constituents controlling antibiotic production by the cyanobacterium nostoc muscorum. | a study has been made to determine which nutrient factors control antibiotic production by the cyanobacterium, nostoc muscorum. a two-phase approach was employed using a factorial method to explore the response surface and a steepest ascent method to climb the response surface to the region of the optimum. it was found that nitrate and iron were the factors significantly affecting antibiotic production; 26.4 mm nitrate and 6 microm iron were the optimal concentrations for maximizing antibiotic p ... | 1991 | 1367529 |
| on-line monitoring of marine cyanobacterial cultivation based on phycocyanin fluorescence. | a novel on-line fluorescence monitoring system for marine cyanobacterial cultivation was developed. this method is based on the measurement of intracellular phycocyanin content, which is the major light harvesting protein. a fluorescence spectrophotometer, equipped with a flow cell connected with a culture liquid recycling tube was used. experiments were carried out using a marine unicellular cyanobacteria synechococcus sp. nkbg 042902 isolated from japanese coastal sea water. we have optimized ... | 1991 | 1367694 |
| n-terminal amino acid sequence of the chlorophyll-binding protein cp-47 of photosystem 2 in the thermophilic cyanobacterium synechococcus elongatus. | | 1992 | 1368306 |
| cloning and nucleotide sequence of a frxc-orf469 gene cluster of synechocystis pcc6803: conservation with liverwort chloroplast frxc-orf465 and nif operon. | a gene, frxc, which is unique to the chloroplast genome of the liverwort marchantia polymorpha, has sequence similarity to nifh, the product of which is an iron protein of a nitrogenase. although frxc is expressed to produce a protein in liverwort chloroplasts, its function is not known. using a probe of liverwort chloroplast dna, a 10.1-kb region containing a gene cluster consisting of open reading frames (orf278-frxc-orf469-orf248) was isolated from the cyanobacterium synechocystis pcc6803. in ... | 1992 | 1368342 |
| generation of lysoglyceroglycolipids in the cyanobacterium, phormidium tenue. | two kinds of lysoglycolipids, monogalactosyl 1-monoacylglycerol and digalactosyl 1-monoacylglycerol were generated in the cyanobacterium, phormidium tenue, when it was stored at -20 degrees for more than 1 month. by comparison of the compositions of fatty acid residues between monogalactosyl 1-monoacylglycerol and monogalactosyl diacylglycerol, digalactosyl 1-monoacylglycerol and digalactosyl diacylglycerol, respectively, the 1-monoacylgalactolipids were presumed to be formed by regioselective d ... | 1992 | 1368418 |
| stereoselective synthesis of marine antibiotic (-)-malyngolide and its stereoisomers. | a convenient synthetic method for the marine antibiotic (-)-malyngolide and its stereoisomers was accomplished from a chiral alpha-alkoxyketone (4), which was readily available as a chiron. chiral quaternary carbon synthons (5a) and (5b) as the key intermediates were constructed by the chelation controlled addition of grignard reagent to 4. the diastereomeric mixture of 5a and 5b was readily transformed into a separable mixture of lactones (7a) and (7b), each of which could be easily separated b ... | 1990 | 1368533 |
| gene encoding a putative zinc finger protein in synechocystis pcc6803. | a 5.5-kb hindiii fragment of synechocystis pcc6803 containing a liverwort (orf316) homolog encoding a putative zinc finger protein was cloned. nucleotide sequence analysis showed that the homology of the amino acid sequence deduced from the orf326 of synechocystis pcc6803 with the counterparts of a liverwort and tobacco was 50% and 46%, respectively. synechocystis orf326 also showed 38% homology with the dedb gene in escherichia coli. the gene organization of the region in these species of organ ... | 1991 | 1368738 |
| multiple rpod-related genes of cyanobacteria. | genomes of many eubacterial strains have been shown to encode for multiple rpod-related genes. in this report, we describe the identification of the multiple rpod-related genes of cyanobacterial strains. dnas of three cyanobacterial strains, anabaena sp. pcc7120, synechococcus sp. pcc7942, and synechocystis sp. pcc6803, were examined by southern hybridization, using a synthetic probe designed for detecting rpod or rpod-related genes. four or five hybridization signals were found in each dna. fou ... | 1992 | 1368828 |
| a perspective on the biotechnological potential of extremophiles. | it is well recognized that many environments considered by man to be extreme are colonized by microorganisms which are specifically adapted to these ecological niches. a diverse range of bacteria, cyanobacteria, algae and yeasts have been isolated from such habitats and it is now widely accepted that these microorganisms provide a valuable resource not only for exploitation in novel biotechnological processes but also as models for investigating how biomolecules are stabilized when subjected to ... | 1992 | 1368881 |
| conjugative gene transfer in marine cyanobacteria: synechococcus sp., synechocystis sp. and pseudanabaena sp. | versatility of gene transfer by transconjugation in marine cyanobacteria was demonstrated. in this study, seven different marine cyanobacteria were used as recipient cells. first, transconjugation was carried out using the mobilizable transposon (tn5) carrying plasmid psup1021. transconjugates were observed in all marine cyanobacteria tested. second, the broad-host-range vector pkt0230 (incq) was tested for transconjugation. pkt230 has been successfully transferred in a marine cyanobacterium syn ... | 1992 | 1368911 |
| the single-copy gene psbs codes for a phylogenetically intriguing 22 kda polypeptide of photosystem ii. | recombinant phages that encode the complete precursor polypeptide for the 22 kda polypeptide associated with photosystem ii have been serologically selected from two lambda gt11 expression libraries made from polyadenylated rna of spinach seedlings. the cdnas hybridize to a 1.3 kb rna species. the precursor protein is comprised of 274 amino acid residues and carries an n-terminal transit peptide of probably 69 amino acid residues. the mature protein exhibits four predicted transmembrane segments ... | 1992 | 1360412 |
| protective effects of ca2+, mg2+, cu2+, and ni2+ on mercury and methylmercury toxicity to a cyanobacterium. | toxicological investigations of the impact of inorganic mercury (hg2+) and methylmercury (ch3hg+) in terms of growth, nh4+ uptake, in vivo glutamine synthetase (transferase) activity, and regulation of toxicity by ca2+, mg2+, cu2+ and ni2+ in the diazotrophic cyanobacterium nostoc calcicola bréb. have been completed. photoautotrophic growth of the cyanobacterium was extremely sensitive to both mercury compounds, ch3hg+ being 2.5 times more toxic than hg2+. although nh4+ uptake was 6 times more s ... | 1992 | 1375141 |
| a nitrate reductase gene of the cyanobacterium synechococcus pcc6301 inferred by heterologous hybridization, cloning and targeted mutagenesis. | dna probes from the narg gene of escherichia coli, which encodes the large polypeptide of respiratory nitrate reductase, show cross-hybridization at low stringency to a single region of the genome of the cyanobacterium synechococcus pcc6301. this segment of cyanobacterial dna was cloned as the insert of plasmid pdn1 and characterized. rna complementary to pdn1 was shown to be substantially more abundant in nitrate grown cells of synechococcus pcc6301 than in ammonium grown cells, thus parallelli ... | 1992 | 1378036 |
| inhibitory effect of a microcystis sp (cyanobacteria) toxin on development of preimplantation mouse embryos. | 1. a soluble toxin, purified from the algae bloom of an eutrophic lake dominated by microcystis, is a very effective inhibitor of early embryo development in a dose-response relationship. 2. two- and 8-cell mouse embryos under the influence of microcystis toxin do not reach the developmental stages of morula and blastocyst, respectively. 3. actin cortex is disorganized without change in the microtubules structure. 4. results are discussed in terms of the possible mechanisms by which the toxin ar ... | 1992 | 1360361 |
| light-regulated expression of the psbd gene family in synechococcus sp. strain pcc 7942: evidence for the role of duplicated psbd genes in cyanobacteria. | the genome of the cyanobacterium synechococcus sp. strain pcc 7942 contains two psbd genes encoding the d2 protein of the photosystem ii reaction center: psbdi, which is cotranscribed as a discistronic message with psbc (the gene encoding cp43, a chlorophyll-a binding protein), and psbdii, which is monocistronic. northern blot analysis of psbd transcripts showed that the two genes responded differently when wild-type cells were shifted from moderate to high light intensity. whereas psbdii transc ... | 1992 | 1372952 |
| sequence of the ribonuclease p rna gene from the cyanobacterium anacystis nidulans. | | 1992 | 1371871 |
| abscisic acid and its synthetic analog in relation to growth and nitrogenase activity of azotobacter chroococcum and nostoc muscorum. | the plant hormone abscisic acid as well as its synthetic analog lab 173711 significantly increased the nitrogenase activity of the bacterium azotobacter chroococcum and the cyanobacterium nostoc muscorum. the effect depended on the concentration of the substances (0.001-10 mg/l) and the age of the cultures. the biomass of the organisms was not significantly influenced. | 1992 | 1387101 |
| role of cyanobacteria in the removal of lignin from the paper mill waste waters. | | 1992 | 1392313 |
| effect of the herbicide diquat on the growth of microalgae and cyanobacteria. | | 1992 | 1392315 |
| light-independent chlorophyll biosynthesis: involvement of the chloroplast gene chll (frxc). | the chlamydomonas reinhardtii chloroplast gene chll (frxc) is shown to be involved in the light-independent conversion of protochlorophyllide to chlorophyllide. the polypeptide encoded by chll contains a striking 53% amino acid sequence identity with the bacteriochlorophyll (bch) biosynthesis bchl gene product in the photosynthetic bacterium rhodobacter capsulatus. in a previous analysis, we demonstrated that bchl was involved in light-independent protochlorophyllide reduction, thereby implicati ... | 1992 | 1392602 |
| large atp synthase operon of the red alga antithamnion sp. resembles the corresponding operon in cyanobacteria. | the large plastid atp synthase operon of the multicellular red alga antithamnion sp. was cloned and the sequence of six atpase genes determined. the operon resembles more the one from cyanobacteria than the atp synthase operon of the chloroplast genome. the gene order is atpi, h, g, f, d and a, coding for the atpase subunits a, c, b', b, delta and alpha, respectively. in green plants, the genes atpg and atpd are located in the nucleus. unlike the situation in three published cyanobacterial atp s ... | 1992 | 1404401 |
| nucleotide sequence of the replication region of the nostoc pcc 7524 plasmid pdu1. | | 1992 | 1408769 |
| organization and expression of a phycobiliprotein gene cluster from the unicellular red alga cyanidium caldarium. | we have sequenced a plastid gene cluster from the unicellular red alga cyanidium caldarium which is located downstream from the psba gene and contains, in the following order, genes for a beta-allophycocyanin-like protein (apcb'), a putative 9.5 kda allophycocyanin linker protein (apcl9.5) and a putative 29 kda phycocyanin linker protein (cpcl29). the apcb' and apcl9.5 genes are organized in the form of an operon. the cpcl29 gene is transcribed monocistronically from the opposite strand of dna. ... | 1992 | 1391770 |
| sequence comparison of two highly homologous phycoerythrins differing in bilin composition. | genes encoding the alpha and beta subunits of class ii phycoerythrin from synechococcus sp. strain wh8103 were cloned and sequenced. the deduced amino acid sequences were compared to class ii phycoerythrin from synechococcus sp. strain wh8020 and found to share 92% identity, yet the proteins differ in the bilin isomer (phycoerythrobilin versus phycourobilin) bound to two of the six chromophore attachment sites. amino acid residues which might contact the bilin at each of the two variable sites w ... | 1992 | 1391782 |
| unsaturation of fatty acids in membrane lipids enhances tolerance of the cyanobacterium synechocystis pcc6803 to low-temperature photoinhibition. | effect of the unsaturation of fatty acids in the glycerolipids of thylakoid membranes on low-temperature photoinhibition of photosynthesis was studied by mutation and transformation of the cyanobacterium synechocystis pcc6803. when grown at 34 degrees c, the wild type contained mono-, di-, and triunsaturated lipids; a mutant, designated fad6, contained mono- and diunsaturated lipids; and a transformant of fad6, with a disrupted gene for desaturation and designated fad6/desa::kmr, contained only ... | 1992 | 1409727 |
| dna sequence and analysis of a cryptic 4.2-kb plasmid from the filamentous cyanobacterium, plectonema sp. strain pcc 6402. | the 4194-bp plasmid, prf1, from plectonema sp. strain pcc 6402 was completely sequenced and analyzed. seven potential open reading frames were identified. the predicted amino acid sequence of open reading frame c (orf c) had identities of 34, 29, and 25% with rep b from the staphylococcus aureus plasmid, pub110; rep from the bacillus amyloliquefaciens plasmid, pftb14; and protein a from the s. aureus plasmid, pc194, respectively. a 75-amino-acid region conserved in these proteins (rep b, rep, an ... | 1992 | 1409974 |
| three new microcystins, cyclic heptapeptide hepatotoxins, from nostoc sp. strain 152. | three new cyclic heptapeptide hepatotoxins, [d-ser1,admadda5]microcystin-lr (1), [d-asp3,-admadda5]microcystin-lhar (2), and [admadda5,mser7]microcystin-lr (3), were isolated from the cyanobacterium (blue-green alga) nostoc sp. strain 152, together with four known microcystins, [admadda5]microcystin-lr (4), [admadda5]microcystin-lhar (5), [d-asp3,-admadda5]microcystin-lr (6), and [dmadda5]microcystin-lr (7). the structures of new microcystins were assigned on the basis of high-resolution fast at ... | 1992 | 1391612 |
| characterization of the genes encoding phycoerythrin in the red alga rhodella violacea: evidence for a splitting of the rpeb gene by an intron. | the phycobilisome of the eukaryotic unicellular red alga rhodella violacea presents in some respects an organization that is intermediate between those of the homologous counterparts found in cyanobacteria (the putative chloroplast progenitor) and more advanced, pluricellular red algae. this suggests evolutionary relationships that we investigated at the genome level. the present work describes the sequences of two rhodophytan phycobilisome genes, rpea and rpeb. these chloroplast genes encode th ... | 1992 | 1409666 |
| complementation of a red-light-indifferent cyanobacterial mutant. | many cyanobacteria alter their phycobilisome composition in response to changes in light wavelength in a process termed complementary chromatic adaptation. mutant strains fdr1 and fdr2 of the filamentous cyanobacterium fremyella diplosiphon are characterized by aberrant chromatic adaptation. instead of adjusting to different wavelengths of light, fdr1 and fdr2 behave as if they are always in green light; they do not respond to red light. we have previously reported complementation of fdr1 by con ... | 1992 | 1409650 |
| cloning and sequencing of the petbd operon from the cyanobacterium synechococcus sp. pcc 7002. | the genes encoding the photosynthetic cytochrome b6 (petb) and subunit 4 (petd) have been cloned and sequenced from the unicellular, photoheterotrophic, transformable cyanobacterium synechococcus sp. pcc 7002, formerly designated agmenellum quadruplicatum. the gene arrangement was found to be similar to that reported in the cyanobacterium nostoc pcc 7906. the dna and derived protein sequences were compared to chloroplast and the other cyanobacterial sequences. by pulsed-field electrophoresis, th ... | 1992 | 1421151 |
| nucleotide sequence of a metallothionein gene of the thermophilic cyanobacterium synechococcus vulcanus. | | 1992 | 1421159 |
| ferredoxin-nadp+ oxidoreductase of c. paradoxa nucleus encoded, but cyanobacterial gene transfer from symbiont to host, an evolutionary mechanism originating new species. | the nucleus encoded cyanoplast ("cyanellar") ferredoxin-nadp + oxidoreductase (fnr) of cyanophora paradoxa, characterized by an n-terminal amino acid sequence, is compared with homologous sequences of other photoautotrophic organisms. the high degree of similarity to the cyanobacterial sequences indicates a cyanobacterial origin. this could be a first direct demonstration of an intertaxonic combination: a gene transfer from an original endocytobiont (cyanobacterium) to the nucleus of its host, o ... | 1992 | 1418237 |
| cloning and characterization of the secy gene from the cyanobacterium synechococcus pcc7942. | the secy gene product is an essential component of the escherichia coli cytoplasmic membrane, which mediates the protein translocation across the membrane. we found a gene homologous to secy in the genome of the cyanobacterium synechococcus pcc7942. the deduced amino acid sequence, 439 amino acids long, shows 43% homology with that of the e. coli secy. the hydrophobic profile suggests that the synechococcus secy protein is an integral membrane protein containing ten membrane-spanning segments, w ... | 1992 | 1420358 |
| antifungal cyclic peptides from the terrestrial blue-green alga anabaena laxa. i. isolation and biological properties. | laxaphycins are responsible for the antifungal and cytotoxic activity of crude ethanolic extracts from the cultured blue-green alga anabaena laxa. these cyclic peptides exhibit an unusual biological synergism when tested for antifungal or cytotoxic effects. the isolation procedure for the peptides, their characterization and biological activities are described here along with experiments demonstrating synergism between the two major laxaphycins. | 1992 | 1429231 |
| antifungal cyclic peptides from the terrestrial blue-green alga anabaena laxa. ii. structures of laxaphycins a, b, d and e. | laxaphycins a and b are the major components in an antifungal mixture of cyclic peptides from the terrestrial blue-green alga anabaena laxa fk-1-2. nmr and ms spectral studies coupled with amino acid analysis indicate that the gross structures of laxaphycins a and b are cyclic (aoc-hse-e-dhb-hyp-hse-phe-leu-ile-ile-leu-gly) where aoc is a 3-aminooctanoic acid residue and cyclic (ala-hleu-gln-n-meile-hasn-thr-pro-leu-thr-ade-val- hleu) where ade is a 3-aminodecanoyl unit, respectively. laxaphycin ... | 1992 | 1429232 |
| excitation energy transfer from phycocyanin to chlorophyll in an apca-defective mutant of synechocystis sp. pcc 6803. | a greenish mutant of the normally blue-green cyanobacterium synechocystis sp. pcc 6803, designated uv6p, has been isolated and characterized. uv6p possesses functional photosystems i and ii (psi and psii) but lacks normal light harvesting phycobilisomes because allophycocyanin is absent and core-specific linker proteins are almost entirely absent. the mutation responsible for the uv6p phenotype has been identified; it is a base substitution which results in the creation of a termination codon wi ... | 1992 | 1429645 |
| identification of anatoxin-a in benthic cyanobacteria (blue-green algae) and in associated dog poisonings at loch insh, scotland. | dog deaths occurred in 1990 and 1991 after the animals drank water containing blooms of benthic cyanobacteria along the shoreline of loch insh, scotland. signs of poisoning in the affected animals and the high neurotoxicity of bloom extracts in laboratory bioassays indicated acute poisoning due to cyanobacterial neurotoxin(s). the neurotoxic blooms consisted largely of benthic oscillatoria species which were also observed in the stomach contents of the poisoned dogs. stomach contents were also n ... | 1992 | 1440622 |
| microcystin-like toxins in different freshwater species of oscillatoria. | in january and september of 1989 and march 1990 blooms of oscillatoria rubescens, oscillatoria tenuis and oscillatoria mougetii were found in lake simbirizzi and lake flumendosa in sardinia, and in lake san puoto in the lazio region of italy. by using different extraction methods and hplc analysis, two microcystin-like toxins (rr-like and yr-like), similar to some of the toxic compounds produced by the cyanophycea microcystis aeruginosa, were detected in these blooms. | 1992 | 1440636 |
| [the evolutionary changes in the amino acid sequences and properties of the atp-synthase in chloroplasts, mitochondria and bacteria]. | studies have been made on atpase from chloroplasts, cyanobacteria and mitochondria of higher plants and animals. no intraspecies and interspecies variability of chloroplast and mitochondrial atpase was found with respect to ph optimum of the activity, to specificity to cations as substrate components, to sensitivity to stimulating and inhibiting anions and ethanol, to optimal stimulating ethanol concentration. intergenus variation of these properties of atpase from chloroplasts, plant mitochondr ... | 1992 | 1441793 |
| semipreparative isolation of individual cyanobacterial heterocyst-type glycolipids by reverse-phase high-performance liquid chromatography. | procedures are described for the quantitative, semi-preparative isolation of individual cyanobacterial heterocyst-type glycolipids (hgs) by reverse-phase hplc (rp-hplc) and the modifications to conventional techniques necessary to prevent significant hg losses during sample preparation. total lipids are obtained from cultures of nitrogen-fixing cyanobacteria by triplicate extraction with 200 packed-cell volumes of chloroform/methanol (1/1, v/v), filtered, and redissolved in chloroform for loadin ... | 1992 | 1443590 |
| quantitative derivatization and high-performance liquid chromatographic analysis of cyanobacterial heterocyst-type glycolipids. | procedures are described for the rapid and quantitative analysis of cyanobacterial heterocyst-type glycolipids (hgs) by normal-phase hplc of their per-o-benzoylated derivatives. total lipids are obtained from 1 ml of nitrogen-fixing cyanobacterial culture by triplicate extraction with chloroform/methanol, 1/1 (v/v), and the hgs are isolated from other complex lipids by preparative silica gel tlc. a c18 solid-phase extraction cartridge is used to ensure quantitative salt-free recovery of the hgs, ... | 1992 | 1443602 |
| effects of mutations at residue 309 of the large subunit of ribulosebisphosphate carboxylase from synechococcus pcc 6301. | previous studies [g. s. hudson et al. (1989) j. biol. chem. 265, 808-814] showed that the faster turnover rates and lower affinities for co2 of ribulosebisphosphate carboxylase/oxygenases from c4 plants, compared to c3 and c3/c4 plants, were specified by the chloroplast-encoded large subunits. in pairs of closely related c3 and c4 species from three genera, these kinetic changes were accompanied by only three to six amino acid residue substitutions, depending on the genus. none of these substitu ... | 1992 | 1444469 |
| photosystem ii function and integrity in spite of drastic protein changes in a conserved region of the d2 protein. | d1 and d2 are structurally related proteins forming the core of the photosystem ii reaction center. the two proteins have several loop regions including an extended stroma-exposed loop between transmembrane helix d and parallel helix de. this loop (the d-de loop) is phylogenetically conserved in both proteins. the role of the d-de loop in photosystem ii was studied in synechocystis sp. pcc 6803 by constructing a chimeric d2 protein in which the stroma-exposed loop of d1 replaced that of d2. in o ... | 1992 | 1445845 |
| energy transfer (deazaflavin-->fadh2) and electron transfer (fadh2-->t <> t) kinetics in anacystis nidulans photolyase. | dna photolyases catalyze the photocycloreversion of cyclobutane pyrimidine dimers. the enzyme from the cyanobacterium anacystis nidulans contains two chromophores, 1,5-dihydroflavin adenine dinucleotide (fadh2) and 7,8-didemethyl-8-hydroxy-5-deazariboflavin (8-hdf). the photophysical/photochemical reactions leading to dna repair were investigated by using time-resolved and steady-state fluorescence spectroscopy. it was found that the excited singlet state of 8-hdf transfers energy to fadh2 at a ... | 1992 | 1445863 |
| glutamate 1-semialdehyde aminotransferase: anomalous enantiomeric reaction and enzyme mechanism. | glutamate 1-semialdehyde aminotransferase (gsa-at) catalyzes near 50% conversion of the racemic mixture of gsa to 5-aminolevulinate (ala), indicating quantitative use of the l-glutamate-derived natural (s)-enantiomer as substrate. this enzymic reaction has been extensively studied with (r,s)-gsa because it is readily purified in high yields following ozonolysis of racemic 4-vinyl-4-aminobutyric acid. however upon addition of (r,s)-gsa, gsa-aminotransferase is converted to the pyridoxal-p or inte ... | 1992 | 1445864 |
| site-directed mutagenesis of the cpa-1 protein of photosystem ii: alteration of the basic residue pair 384,385r to 384,385g leads to a defect associated with the oxygen-evolving complex. | the psbb gene encodes the intrinsic chlorophyll-a binding protein cpa-1 (cp-47), a component of photosystem ii in higher plants, algae, and cyanobacteria. oligonucleotide-directed mutagenesis was used to introduce mutations into a segment of the psbb gene encoding the large extrinsic loop region of cpa-1 in the cyanobacterium synechocystis sp. pcc 6803. altered psbb genes were introduced into a mutant recipient strain (del-1) of synechocystis in which the genomic psbb gene had been partially del ... | 1992 | 1445882 |
| role of the carboxy terminus of polypeptide d1 in the assembly of a functional water-oxidizing manganese cluster in photosystem ii of the cyanobacterium synechocystis sp. pcc 6803: assembly requires a free carboxyl group at c-terminal position 344. | the d1 polypeptide of the photosystem ii (psii) reaction center is synthesized as a precursor polypeptide which is posttranslationally processed at the carboxy terminus. it has been shown in spinach that such processing removes nine amino acids, leaving ala344 as the c-terminal residue [takahashi, m., shiraishi, t., & asada, k. (1988) febs lett. 240, 6-8; takahashi, y., nakane, h., kojima, h., & satoh, k. (1990) plant cell physiol. 31, 273-280]. we show here that processing on the carboxy side o ... | 1992 | 1420199 |
| thermally-induced delayed fluorescence of photosystem i and ii chlorophyll in thermophilic cyanobacterium synechococcus elongatus. | stationary delayed fluorescence (df) of chlorophyll in isolated membrane preparations from thermophilic cyanobacterium synechococcus elongatus was investigated as a function of temperature. two peaks at different temperatures were observed. the low-temperature peak (54-60 degrees c) coincided with the main maximum of the thermally-induced delayed fluorescence of chlorophyll in intact cells and psii-particles with active oxygen-evolving system. the high-temperature peak (78 degrees c) coincided w ... | 1992 | 1426973 |
| a laser flash absorption spectroscopy study of anabaena sp. pcc 7119 flavodoxin photoreduction by photosystem i particles from spinach. | electron transfer from p700 in photosystem i (psi) particles from spinach to anabaena sp. pcc 7119 flavodoxin has been studied using laser flash absorption spectroscopy. a non-linear protein concentration dependence of the rate constants was obtained, suggesting a two-step mechanism involving complex formation (k = 3.6 x 10(7) m-1.s-1) followed by intracomplex electron transfer (k = 270 s-1). the observed rate constants had a biphasic dependence on the concentrations of nacl or mgcl2, with maxim ... | 1992 | 1446742 |
| characterization of a spinach psbs cdna encoding the 22 kda protein of photosystem ii. | an intrinsic 22 kda polypeptide is found associated with the oxygen-evolving photosystem ii (psii) core complex in all green plants and cyanobacteria so far examined, although it does not appear to be required for oxygen evolution. amino acid sequence information obtained from the purified 22 kda protein was used to construct a probe that was employed to isolate a full-length cdna clone encoding the 274-residue precursor of the 22 kda protein. hydropathy plot analysis predicts the existence of f ... | 1992 | 1451805 |
| beyond the barcoo--probable human tropical cyanobacterial poisoning in outback australia. | to determine the cause of a disease known variously as "barcoo fever, barcoo spews, barcoo sickness", or simply "the barcoo", once prevalent in outback northern and central australia. | 1992 | 1454012 |
| synechococcus pcc6301 mutants possessing resistance to the tetrapyrrole biosynthesis inhibitor gabaculine. | | 1992 | 1426569 |
| identification of a hema gene from synechocystis by complementation of an e. coli hema mutant. | | 1992 | 1459859 |
| structure and expression of a cyanobacterial ilvc gene encoding acetohydroxyacid isomeroreductase. | acetohydroxyacid isomeroreductase (ahair) is the shared second enzyme in the biosynthetic pathways leading to isoleucine and valine. ahair is encoded by the ilvc gene in bacteria. a 1,544-bp fragment of genomic dna containing the ilvc gene was cloned from the cyanobacterium synechocystis sp. strain pcc 6803, and the complete nucleotide sequence was determined. the identity of the gene was established by comparison of the nucleotide and derived peptide sequences with those of other ilvc genes. th ... | 1992 | 1459938 |
| participation of a cyanobacterial s layer in fine-grain mineral formation. | cyanobacteria belonging to the synechococcus group are ubiquitous inhabitants of diverse marine and freshwater environments. through interactions with the soluble constituents of their aqueous habitats, they inevitably affect the chemistry of the waters they inhabit. synechococcus strain gl24 was isolated from fayetteville green lake, new york, where it has a demonstrated role in the formation of calcitic minerals. in order to understand the detailed interactions which lead to mineral formation ... | 1992 | 1459945 |
| core mutations of synechococcus sp. pcc 7002 phycobilisomes: a spectroscopic study. | three cyanobacterial strains harboring mutations affecting phycobilisome (pbs) cores were studied using steady state absorption and fluorescence and time-resolved fluorescence. the apcf mutant, missing beta 18, and the apcdf mutant, missing both alpha apb and beta 18, showed only small spectroscopic differences from the wild-type strain; their pbs emission was blue shifted by 10 nm, whereas their absorption spectra and time-resolved fluorescence kinetics were virtually unchanged. the third mutan ... | 1992 | 1460543 |
| thermoluminescence and flash-induced oxygen yield in herbicide resistant mutants of the d1 protein in synechococcus pcc7942. | several strains of synechococcus pcc7942 carrying point mutations in the gene psba were studied by thermoluminescence and polarographic measurement of flash-induced oxygen yield. the following results were obtained: (a) replacement of ser-264 in d1 by ala (mutant di1) or gly (mutant g264) resulting in dcmu and atrazine resistance leads to a downshift of the thermoluminescence (tl) b-band peak temperature from 40 degrees c in wild-type thylakoids to about 30 degrees c. in dark adapted samples of ... | 1992 | 1445937 |
| genetic analysis of photosynthesis in prokaryotes and lower eukaryotes. | | 1992 | 1458026 |
| formation, characterization, and toxicity of the glutathione and cysteine conjugates of toxic heptapeptide microcystins. | microcystins lr, yr, and rr, cyclic heptapeptide hepatotoxins produced by cyanobacteria, were synthetically converted into glutathione (gsh) and cysteine (cys) conjugates. fast atom bombardment mass spectra showed [m + h]+ ions corresponding to gsh and cys conjugates of microcystins lr, yr, and rr for the obtained compounds. 1h nmr spectral analyses revealed that two singlet signals of olefinic protons of n-methyldehydroalanine (mdha) in microcystins disappeared in the conjugates, confirming tha ... | 1992 | 1445998 |
| restoration of the wild-type locus in an rubp carboxylase/oxygenase mutant of synechocystis pcc 6803 via targeted gene recombination. | the interaction between homologous dna sequences, distant from each other in the chromosome, was examined in the cyanobacterium synechocystis pcc 6803. most of the rbcl gene encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco) was duplicated in the genome by a targeted insertion of a 3'-truncated gene copy into the psb a-i locus. both rbcl genes, in the psb a-i region and at the rbc locus, were non-functional; the former due to the 3' truncation, and the latter due ... | 1992 | 1465099 |
| migs--a simple graphics utility program. | | 1992 | 1468023 |
| purification, characterization and function of dihydrolipoamide dehydrogenase from the cyanobacterium anabaena sp. strain p.c.c. 7119. | a dihydrolipoamide dehydrogenase (dihydrolipoamide: nad+ oxidoreductase, ec 1.8.1.4) (dld) has been found in the soluble fraction of cells of both unicellular (synechococcus sp. strain p.c.c. 6301) and filamentous (calothrix sp. strain p.c.c. 7601 and anabaena sp. strain p.c.c. 7119) cyanobacteria. dld from anabaena sp. was purified 3000-fold to electrophoretic homogeneity. the purified enzyme exhibited a specific activity of 190 units/mg and was characterized as a dimeric fad-containing protein ... | 1992 | 1471997 |
| the hit protein family: a new family of proteins present in prokaryotes, yeast and mammals. | by comparing the sequence of a putative translation product from a saccharomyces cerevisiae split gene with several data-bases, i have uncovered a new protein family. members of this family are found in prokaryotes as well as in lower and higher eukaryotes. the function of these proteins is unknown but they share a characteristic histidine triad that may be involved in zinc binding. this group of protein has been named the hit protein family. | 1992 | 1472710 |
| isolation and identification of the restriction endonuclease ptai from phormidium tadzschicicum, an isoschizomer of bspmii. | | 1992 | 1480496 |
| isolation and structures of microcystins from a cyanobacterial water bloom (finland). | a hepatotoxic cyanobacterial (blue-green algal) water bloom was collected from a constructed water reservoir in finland. the water bloom contained two cyanobacterial species, microcystis aeruginosa and aphanizomenon flos-aquae. two hepatotoxins, 1 and 2, were isolated from extracts of lyophilized cells. the structures of 1 and 2 were assigned based upon their amino acid analyses on a waters pico tag hplc system and a chiral gc capillary column (chirasil val iii), fast atom bombardment mass spect ... | 1992 | 1485342 |
| pressure and low temperature effects on the fluorescence emission spectra and lifetimes of the photosynthetic components of cyanobacteria. | the effects of hydrostatic pressure on the excited state reactions of the photosynthetic system of cyanobacteria were studied with the use of stationary and dynamic fluorescence spectroscopy. when the cells were excited with blue light (442 nm), hydrostatic pressure promoted a large increase in the fluorescence emission of the phycobilisomes (pbs). when pbs were excited at 565 nm, the shoulder originating from photosystem ii (psii) emission (f685) disappeared under 2.4 kbar compression, suggesti ... | 1992 | 1489915 |
| the cyanobacterium oscillatoria erythraea--a potential source of toxin in the ciguatera food-chain. | a compound lethal to mice (i.p.) was extracted from samples of oscillatoria erythraea, four species of mollusc and one species of molluscivorous teleost collected from the south-east coast of queensland, australia, during and shortly after o. erythraea blooms. the compound was chemically indistinguishable from ciguatoxin (ctx) on the basis of solvent extraction and partitioning and silicic acid chromatography. residues derived from toxic samples elicited signs of intoxication, death and histopat ... | 1992 | 1493884 |
| phycocyanin alpha-subunit phycocyanobilin lyase. | phycobiliproteins, unlike other light-harvesting proteins involved in photosynthesis, bear covalently attached chromophores. the bilin chromophores are attached through thioether bonds to cysteine residues. the cyanobacterium synechococcus sp. pcc 7002 has eight distinct bilin attachment sites on seven polypeptides, all of which carry the same chromophore, phycocyanobilin. when two genes in the phycocyanin operon of this organism, cpce and cpcf, are inactivated by insertion, together or separate ... | 1992 | 1495995 |
| mutations in the d1 subunit of photosystem ii distinguish between quinone and herbicide binding sites. | the structure-activity relationships of the plastoquinone qb binding domain in the d1 subunit of photosystem ii (psii) were investigated by characterization of mutations introduced in the d1 protein. eight novel point mutations in the gene psba, which encodes d1, were generated in the cyanobacterium synechocystis pcc6803 by site-specific mutagenesis in vitro. the effects of the resulting modifications in d1 on electron transfer in psii and on herbicide binding were analyzed. the results extend t ... | 1992 | 1498597 |
| an improved method for the isolation of chromosomal dna from various bacteria and cyanobacteria. | | 1992 | 1508700 |
| evidence for an ultraviolet sunscreen role of the extracellular pigment scytonemin in the terrestrial cyanobacterium chlorogloeopsis sp. | the proposed photoprotective role of the uv-a absorbing, extracellular pigment scytonemin was studied in the terrestrial cyanobacterium chlorogloeopsis sp. strain o-89-cgs(1). uv-a (315-400 nm) caused growth delay, cell growth restarting only when scytonemin had accumulated in the extracellular envelopes. cultures with scytonemin were more resistant to photoinhibition of photosynthesis than cultures without scytonemin, the differential resistance being much greater to uv-a-caused photoinhibition ... | 1992 | 1508978 |
| effect of the cyanobacterial (blue-green algal) toxins from microcystis aeruginosa on isolated enterocytes from the chicken small intestine. | livestock deaths, and clinical reports of human injury, follow the consumption of toxic blue-green algae. the experiments described show that isolated intestinal enterocytes from chicks are both deformed and killed by exposure to microcystis toxins, in a dose-dependent and time-dependent manner. the enterocytes were protected from toxicity by deoxycholate, bromosulphothalein and rifampicin. it was concluded that the gastroenteritis clinically associated with accidental microcystis ingestion is l ... | 1992 | 1509499 |
| biological effects of tolytoxin (6-hydroxy-7-o-methyl-scytophycin b), a potent bioactive metabolite from cyanobacteria. | tolytoxin, a macrocyclic lactone, is a potent antifungal antibiotic, exhibiting mics in the range of 0.25 to 8 nanomolar. tolytoxin also inhibits the growth of a variety of mammalian cells at similar doses, without specific inhibition of macromolecular synthesis. the effects in mammalian cells are primarily cytostatic, with cell death being time- and dose-dependent. tolytoxin is highly toxic to mice, exhibiting an ld50 (ip) of 1.5 mg/kg. no antibacterial, antiviral, or hemolytic activities were ... | 1992 | 1510566 |
| oxygen yield and thermoluminescence characteristics of a cyanobacterium lacking the manganese-stabilizing protein of photosystem ii. | previous experiments have shown that a synechocystis sp. pcc 6803 mutant (delta psbo) lacking the extrinsic manganese-stabilizing protein (msp) exhibits impaired, but significant levels of h2o-splitting activity [burnap, r., & sherman, l.a. (1991) biochemistry 30, 440-446]. [14c]dcmu-binding experiments now show that the number and affinity of dcmu-binding sites (normalized to chlorophyll) are equivalent in delta psbo and the wild type, suggesting equal concentrations of assembled reaction cente ... | 1992 | 1510930 |
| the complete nucleotide sequence of the gene (rpod1) encoding the principal sigma factor of the rna polymerase from the cyanobacterium synechococcus sp. strain pcc7942. | the complete nucleotide sequence of rpod1 gene from synechococcus pcc7942 has been determined. the nucleotide data have indicated the presence of an open reading frame of 1155 base pairs encoding a polypeptide which shares the framework structure for principal sigma factors of eubacterial strains. | 1992 | 1511015 |
| molecular characterization of the genes encoding acetohydroxy acid synthase in the cyanobacterium spirulina platensis. | the enzyme acetohydroxy acid synthase (ahs), which catalyses the first common step in the biosynthesis of isoleucine, leucine and valine, has been demonstrated to be present in spirulina platensis in two isoenzymic forms. the complete nucleotide sequences of the genes ilvx and ilvw encoding these two enzymes have been determined. sequence analysis revealed the presence of two open reading frames, of 1836 and 1737 nucleotides for ilvx and ilvw, respectively. the predicted amino acid sequences of ... | 1992 | 1512571 |