| the environment of [2fe-2s] clusters in ferredoxins: the role of residue 45 probed by site-directed mutagenesis. | the biochemical and biophysical properties of the ala45ser mutant of the [2fe-2s] ferredoxin from vegetative cells of the cyanobacterium anabaena sp. 7120 are described. this novel protein, which incorporates the residue present in many higher plant ferredoxins into the analogous position of a typical cyanobacterial ferredoxin, was prepared to probe the origin of the characteristic spectrochemical and functional differences between the ferredoxins from these two sources. the variant protein was ... | 1995 | 7577985 |
| structure and evolution of paramecium hemoglobin genes. | hemoglobin (hb) genes have been cloned from three different species of ciliated protists, p. multimicronucleatum, p. triaurelia and p. jenningsi. southern blotting of the genomic dnas using the p. caudatum hb cdna showed both intraspecies variation in different stocks of p. caudatum and interspecies variation within the genus paramecium. the isolated hb genes were composed of 118, 117 and 117 codons, and interrupted by a short intron with 27, 29 and 29 bp at the same position, in p. multimicronu ... | 1995 | 7578257 |
| absence of psac subunit allows assembly of photosystem i core but prevents the binding of psad and psae in synechocystis sp. pcc6803. | in photosystem i (psi) of oxygenic photosynthetic organisms the psac polypeptide, encoded by the psac gene, provides the ligands for two [4fe-4s] clusters, fa and fb. unlike other cyanobacteria, two different psac genes have been reported in the cyanobacterium synechocystis 6803, one (copy 1) with a deduced amino acid sequence identical to that of tobacco and another (copy 2) with a deduced amino acid sequence similar to those reported for other cyanobacteria. insertion of a gene encoding kanamy ... | 1995 | 7579183 |
| two heterocyst-specific dna rearrangements of nif operons in anabaena cylindrica and nostoc sp. strain mac. | two site-specific dna rearrangements occur during heterocyst differentiation in the cyanobacterium anabaena sp. strain pcc 7120: the deletion of an 11 kb element from within the nifd gene and the deletion of a 55 kb element from within the fdxn gene. three nostoc and six anabaena strains were screened for the presence of the nifd and fdxn elements by southern hybridization with anabaena pcc 7120 dna probes. eight of the nine strains contained dna sequences that were similar to the nifd element. ... | 1995 | 7582007 |
| nucleotide sequence of a putative sensory kinase gene from the cyanobacterium, anacystis nidulans 6301. | the nucleotide sequence of a 2,146 bp portion of the anacystis nidulans (synechococcus pcc6301) genome has been determined. this region contains an open reading frame (orf) of 392 codons, whose predicted protein sequence shows partial homology to those of e. coli phom and envz. hence orf392 is suggested to be a sensory kinase gene in cyanobacteria. | 1994 | 7584034 |
| genes encoding the group i intron-containing trna(leu) and subunit l of nadh dehydrogenase from the cyanobacterium synechococcus pcc 6301. | a part of the trna(leu)(uaa) gene containing a 240-nucleotide group i intron was amplified by pcr from cyanobacterium synechococcus pcc 6301 genomic dna. the pre-trna synthesized from the cloned pcr product was efficiently self-spliced in vitro under physiological conditions. the gene encoding the trna(leu)(uaa), trnl-uaa, was isolated from a synechococcus pcc 6301 genomic library and the nucleotide sequence of a 2,167-bp portion was determined. the trnl-uaa consists of a 34-bp 5' exon, a 240-bp ... | 1995 | 7584050 |
| tubercidin stabilizes microtubules against vinblastine-induced depolymerization, a taxol-like effect. | a sensitive assay for the detection of microtubule-stabilizing agents [1] was used to screen an extensive collection of cyanobacterial and microalgal extracts. the hydrophilic extract of the cyanobacterium, plectonema radiosum (uh isolate ic-70-1), exhibited microtubule-stabilizing activity. bioassay-directed purification of the active compound yielded tubercidin (7-deazaadenosine), a potent cytotoxic nucleoside analog. further studies revealed that tubercidin protected a population of cellular ... | 1995 | 7585466 |
| molecular biological analysis of a bidirectional hydrogenase from cyanobacteria. | an 8.9-kb segment with hydrogenase genes from the cyanobacterium anabaena variabilis has been cloned and sequenced. the sequences show homology to the methyl-viologen-reducing hydrogenases from archaebacteria and, even more striking, to the nad(+)-reducing enzymes from alcaligenes eutrophus and nocardia opaca as well as to the nadp(+)-dependent protein from desulfovibrio fructosovorans. the cluster from a. variabilis contains genes coding for both the hydrogenase heterodimer (hoxh and hoxy) and ... | 1995 | 7588754 |
| the covalent linkage of a viologen to a flavoprotein reductase transforms it into an oxidase. | chemical cross-linkage of the positively charged viologen n-methyl-n'-(aminopropyl)-4-4'-bipyridinium dibromide (apmv) to the enzyme ferredoxin-nadp+ reductase from the cyanobacterium anabaena pcc 7119 has been performed using the carbodiimide 1-ethyl[3-(3-dimethylaminopropyl)]carbodiimide. 0.5-1 mol, depending on the preparation, is introduced for each mol enzyme. the residue involved in the covalent linkage with the viologen, glu139, has been identified using hplc separation of the modified pr ... | 1995 | 7588806 |
| functional and structural changes of the photosystem ii complex induced by high irradiance in cyanobacterial cells. | a gradual disintegration of the photosystem ii (psii) complex, initiated by a release of the chlorophyll-protein cp43, was identified during low-temperature illumination of synechococcus cells. this process was slower compared to the decline of the psii primary charge separation activity, and much slower than the photoinactivation of oxygen evolution. all three processes were slowed down in the presence of diuron. the results indicate that when the psii repair was blocked, the inactivation of ch ... | 1995 | 7588816 |
| a novel repetitive sequence lies near the gene encoding a cytosine methyltransferase in the cyanobacterium dactylococcopsis salina. | an unusual cluster of tandemly repeated dna sequences (trs) was found downstream from the gene encoding dsav methyltransferase, the dna modification enzyme in the dsav restriction-modification system found in a strain of dactylococcopsis salina (ds). the repeat unit is about 32-bp long and is present 13 times in the cluster. each repeat unit can be divided into two distinct parts based on the level of sequence conservation and evolution. hybridization of ds dna with a probe specific for this clu ... | 1995 | 7590324 |
| phosphorylation of the pii protein (glnb gene product) in the cyanobacterium synechococcus sp. strain pcc 7942: analysis of in vitro kinase activity. | the pii protein in the cyanobacterium synechococcus sp. strain pcc 7942 signals the cellular state of nitrogen assimilation relative to co2 fixation by being phosphorylated at a seryl residue. in this study, we first determined the location of the phosphorylated seryl residue within the pii amino acid sequence. the phosphorylation site exhibits an rxs motif, a recognition sequence characteristic for cyclic amp-dependent protein serine kinases from eukaryotes. we established an in vitro pii phosp ... | 1995 | 7592328 |
| a novel nitrite reductase gene from the cyanobacterium plectonema boryanum. | the gene (nira) for nitrite reductase was cloned from the nonheterocystous, filamentous cyanobacterium plectonema boryanum. the predicted protein consists of 654 amino acids and has a calculated molecular weight of 72,135. the deduced amino acid sequence from positions 1 to 511 is strongly similar to the entire sequence of the ferredoxin-dependent nitrite reductases from other phototrophs, while the remainder of the protein is unique to the plectonema nitrite reductase. the c-terminal portion of ... | 1995 | 7592378 |
| genetic evidence of a major role for glucose-6-phosphate dehydrogenase in nitrogen fixation and dark growth of the cyanobacterium nostoc sp. strain atcc 29133. | heterocysts, sites of nitrogen fixation in certain filamentous cyanobacteria, are limited to a heterotrophic metabolism, rather than the photoautotrophic metabolism characteristic of cyanobacterial vegetative cells. the metabolic route of carbon catabolism in the supply of reductant to nitrogenase and for respiratory electron transport in heterocysts is unresolved. the gene (zwf) encoding glucose-6-phosphate dehydrogenase (g6pd), the initial enzyme of the oxidative pentose phosphate pathway, was ... | 1995 | 7592384 |
| the hglk gene is required for localization of heterocyst-specific glycolipids in the cyanobacterium anabaena sp. strain pcc 7120. | mutant strain 543 of the cyanobacterium anabaena sp. strain pcc 7120 was originally isolated as a fox- mutant following chemical mutagenesis. ultrastructural analysis shows that in nitrogen-replete media the vegetative cells of the mutant are more cylindrical and have thicker septa than those of the wild type, while in nitrogen-free media the mutant heterocysts lack the normal glycolipid layer external to the cell wall. although this layer is absent, strain 543 heterocysts nevertheless contain h ... | 1995 | 7592418 |
| subunit interactions and protein stability in the cyanobacterial light-harvesting proteins. | strain 4r is a phycocyanin-minus mutant of the unicellular cyanobacterium synechocystis sp. strain 6803. although it lacks the light-harvesting protein phycocyanin, 4r has normal levels of phycocyanin (cpc) transcripts. sequence analysis of the cpcb gene encoding the phycocyanin beta subunit shows an insertion mutation in 4r that causes early termination of translation. other work has shown that the phycocyanin alpha subunit and the linker proteins encoded on the cpc transcripts are all function ... | 1995 | 7592470 |
| heterologous assembly and rescue of stranded phycocyanin subunits by expression of a foreign cpcba operon in synechocystis sp. strain 6803. | light harvesting in cyanobacteria is performed by the biliproteins, which are organized into membrane-associated complexes called phycobilisomes. most phycobilisomes have a core substructure that is composed of the allophycocyanin biliproteins and is energetically linked to chlorophyll in the photosynthetic membrane. rod substructures are attached to the phycobilisome cores and contain phycocyanin and sometimes phycoerythrin. the different biliproteins have discrete absorbance and fluorescence m ... | 1995 | 7592471 |
| hemodynamic and calorimetric changes induced by microcystin-lr in the rat. | microcystin-lr, a cyclic peptide from the cyanobacterium microcystis aeruginosa, given at acutely toxic doses causes severe hepatic interstitial hemorrhage. hemodynamic, calorimetric and acid-base balance changes after i.v. microcystin were measured. the effect of isoproterenol, dopamine, methylprednisolone and whole-blood volume expansion on the immediate hemodynamic effects after toxin administration were also evaluated. a dose of 100 micrograms kg-1 was invariably lethal for rats in all studi ... | 1995 | 7594200 |
| a novel mechanism of glutamine synthetase inactivation by ammonium in the cyanobacterium synechocystis sp. pcc 6803. involvement of an inactivating protein. | the glutamine synthetase of the cyanobacterium synechocystis sp. pcc 6803 can be inactivated in vivo by ammonium addition by a new mechanism that involves the binding to the enzyme of an inactivating factor. this binding provokes a different mobility of the inactive enzyme with respect to the active form in non-denaturing page, but not in sds-page. this modification of glutamine synthetase is for the first time visualized by western blot analysis of the active and inactive forms. cross-linking e ... | 1995 | 7601281 |
| circadian orchestration of gene expression in cyanobacteria. | we wanted to identify genes that are controlled by the circadian clock in the prokaryotic cyanobacterium synechococcus sp. strain pcc 7942. to use luciferase as a reporter to monitor gene expression, bacterial luciferase genes (luxab) were inserted randomly into the synechococcus genome by conjugation with escherichia coli and subsequent homologous recombination. the resulting transformed clones were then screened for bioluminescence using a new developed cooled-ccd camera system. we screened ap ... | 1995 | 7601351 |
| molecular cloning of the cyanobacterial adenylate cyclase gene from the filamentous cyanobacterium anabaena cylindrica. | molecular cloning of the structural gene for adenylate cyclase (cya) of the cyanobacterium anabaena cylindrica was carried out by complementation of an escherichia coli strain defective in the cya gene. the cya-defective strain produced significant amounts of cyclic amp when it was transformed with the cya gene isolated from a. cylindrica. this gene encodes a polypeptide consisting of 502 amino acid residues (molecular weight, 55,300). the deduced primary protein structure showed that the carbox ... | 1995 | 7601856 |
| two enzymes together capable of cysteine biosynthesis are encoded on a cyanobacterial plasmid. | the cyanobacterium synechococcus sp. pcc 7942 contains two endogenous, genetically cryptic plasmids of 8.0 and 48.5 kb, which have been designated pans and panl, respectively. characterization of the 3.8 kb ba6 bamhi fragment of panl identified three open reading frames which were transcriptionally regulated by sulfur availability and the protein cysr. one of these genes, designated srpg, encodes a protein which exhibits 67% amino acid identity to the escherichia coli enzyme o-acetyl-l-serine (t ... | 1995 | 7603442 |
| mutational analysis of photosystem i polypeptides in the cyanobacterium synechocystis sp. pcc 6803. targeted inactivation of psai reveals the function of psai in the structural organization of psal. | we cloned, characterized, and inactivated the psai gene encoding a 4-kda hydrophobic subunit of photosystem i from the cyanobacterium synechocystis sp. pcc 6803. the psai gene is located 90 base pairs downstream from psal, and is transcribed on 0.94- and 0.32-kilobase transcripts. to identify the function of psai, we generated a cyanobacterial strain in which psai has been interrupted by a gene for chloramphenicol resistance. the wild-type and the mutant cells showed comparable rates of photoaut ... | 1995 | 7608190 |
| novel monoclonal antibodies against microcystin and their protective activity for hepatotoxicity. | six monoclonal antibodies (mabs) to microcystin-lr (mclr), a cyclic heptapeptide hepatotoxin isolated from the cyanobacterium microcystis aeruginosa, were produced. they showed the protective effects on hepatotoxicity of mclr in vitro and in vivo, and on the inhibition of protein phosphatase by mclr. competitive enzyme-linked immunosorbent assays with various microcystins revealed that the six mabs recognized a part of the molecule, in particular, a tertial structure around adda, 3-amino-9-metho ... | 1995 | 7613739 |
| laser flash absorption spectroscopy study of ferredoxin reduction by photosystem i: spectral and kinetic evidence for the existence of several photosystem i-ferredoxin complexes. | the existence of three first-order phases has been previously reported for the reduction of soluble ferredoxin by photosystem i (psi), both from the cyanobacterium synechocystis sp. pcc 6803 (at ph 8 and in the presence of salts) [sétif, p. q. y., & bottin, h. (1994) biochemistry 33, 8495-8504]. the spectra of these three phases (t1/2 < 1 microsecond, = 13-20 and 103-123 microseconds) have been measured between 460 and 600 nm. all of them are fully consistent with electron transfer from (fa,fb)- ... | 1995 | 7619805 |
| tandem sequence duplications functionally complement deletions in the d1 protein of photosystem ii. | obligate photoheterotrophic mutants of the cyanobacterium synechocystis sp. pcc 6803 that carry deletions of conserved residues in the plastoquinone-binding niche of the d1 protein were used to select for spontaneous mutations that restore photoautotrophic growth. spontaneous pseudorevertants emerged from two deletion mutants, delta yniv246-9 and delta nn266-7, when the cultures were maintained long after the carbon source (glucose) had been depleted from the medium and cells had reached station ... | 1995 | 7622458 |
| isolation of a cyclic carbonate, a gamma-butyrolactone, and a new indole derivative from the marine cyanobacterium lyngbya majuscula. | | 1995 | 7623035 |
| malyngamide h, an ichthyotoxic amide possessing a new carbon skeleton from the caribbean cyanobacterium lyngbya majuscula. | guided by ichthyotoxic activity against goldfish, a new lipopeptide, malyngamide h [1], and its corresponding free acid, 7-methoxytetradec-4(e)-enoic acid [2], have been isolated from the tropical marine cyanobacterium lyngbya majuscula. the structure of the new carbon skeleton borne by malyngamide h was elucidated on the basis of spectroscopic analysis, mainly 2d nmr. the absolute stereochemistry of the cyclohexenone moiety of malyngamide h [1] was deduced by a combination of 2d noesy and excit ... | 1995 | 7623050 |
| comparison of psbo and psbh deletion mutants of synechocystis pcc 6803 indicates that degradation of d1 protein is regulated by the qb site and dependent on protein synthesis. | mutants of the cyanobacterium synechocystis pcc 6803 lacking the psbo or psbh gene are more vulnerable to photoinhibition than the wild type (wt). in the case of the psbo-less mutant, the increased sensitivity to photodamage is also accompanied by accelerated turnover of the d1 protein and a rapid rate of recovery on transfer to non-photoinhibitory conditions. in contrast, in low light the psbh-less mutant has a poor ability to recover after photoinhibition and has a reduced rate of d1 turnover ... | 1995 | 7626631 |
| isolation and characterization of a cdna encoding the seca protein from spinach chloroplasts. evidence for azide resistance of sec-dependent protein translocation across thylakoid membranes in spinach. | thylakoid membranes of chloroplasts in higher plants harbor different pathways for the translocation of proteins. one of these routes is related to the prokaryotic sec pathway, which mediates the secretion of particular proteins into the periplasmic space and involves the seca protein as an essential component. we have isolated a full size cdna of 3739 nucleotides encoding the seca homologue from spinach. it contains an open reading frame of 1036 codons corresponding to a polypeptide with a calc ... | 1995 | 7629156 |
| organization of photosystem i polypeptides. identification of psab domains that may interact with psad. | psaa and psab are homologous integral membrane-proteins that form the heterodimeric core of photosystem i (psi). we used subunit-deficient psi complexes from the mutant strains of the cyanobacterium synechocystis sp. pcc 6803 to examine interactions between psab and other psi subunits. incubation of the wild-type psi with thermolysin yielded 22-kd c-terminal fragments of psab that were resistant to further proteolysis. modification of the wild-type psi with n-hydroxysuccinimidobiotin and subsequ ... | 1995 | 7630936 |
| the two psba genes from the thermophilic cyanobacterium synechococcus elongatus. | | 1995 | 7630952 |
| a synechococcus gene encoding a putative pore-forming intrinsic membrane protein. | a cyanobacterium, synechococcus species pcc7942, has a gene encoding a copper-transporting p-type atpase, which is located in the thylakoid membrane. at the 5'-upstream of this atpase gene, we identified another gene, which was supposed to be implicated in a copper-transport process. this novel gene was found to encode a putative pore-forming membrane protein that belongs to a growing family of homologous intrinsic membrane proteins (the mip family of proteins), which include the major intrinsic ... | 1995 | 7632713 |
| genetic structure of the dnaa region of the cyanobacterium synechocystis sp. strain pcc6803. | we have cloned and sequenced the dnaa region of synechocystis sp. strain pcc6803, a bacterium with a light-dependent cell cycle. the dnaa gene product, dnaa, is the central factor for replication initiation in bacteria. the deduced amino acid sequence of the protein encoded by the cyanobacterial dnaa gene is 45% identical to dnaa of bacillus subtilis and fits very well into the homology pattern of the known eubacterial dnaa proteins. the genetic environment of the synechocystis sp. strain pcc680 ... | 1995 | 7635812 |
| photoelectric characterization of forward electron transfer to iron-sulfur centers in photosystem i. | the photoelectric response of oriented ps i membranes from the cyanobacterium synechocystis 6803 has been investigated in the nanosecond time range. besides an unresolved rapidly rising phase, there is a further positive electrogenic phase with a rise time constant of 220 +/- 20 ns. the amplitude of the 220-ns phase is 66 +/- 10% that of the subnanosecond phase. the fast phase contains two kinetic components faster than 100 ps, which have recently been resolved and attributed to primary charge s ... | 1995 | 7640279 |
| cloning and sequencing of the nitrate transport system from the thermophilic, filamentous cyanobacterium phormidium laminosum: comparative analysis with the homologous system from synechococcus sp. pcc 7942. | a genomic region from the filamentous, thermophilic non-n2-fixing cyanobacterium phormidium laminosum was cloned and sequenced. it includes the nitrite reductase gene (nira) and three other genes (nrta, b and c) located downstream of nira, which are related to the nitrate transport system on the basis of a comparison with the homologous system from synechococcus sp. pcc 7942. no additional nitrate assimilation-related genes were identified in about 5 kb sequenced downstream of nrtc. all four gen ... | 1995 | 7647306 |
| isolation and structural characterization of trimeric cyanobacterial photosystem i complex with the help of recombinant antibody fragments. | a monoclonal antibody was derived from mice immunized with the native trimeric, photosystem i (psi) complex from the cyanobacterium synechococcus pcc 7002 which reacts with a conformational epitope of the psi complex. as seen by immunoelectron microscopy, the mab bound to the stromal side of the thylakoid membranes. the dna sequence encoding variable regions of the mab was cloned into recombinant plasmids, sequenced and expressed in escherichia coli. elisa, western blots and immunoelectron micro ... | 1995 | 7649183 |
| bioaccumulation of paralytic shellfish poisoning (psp) toxins from the cyanobacterium anabaena circinalis by the freshwater mussel alathyria condola. | the australian freshwater mussel alathyria condola accumulated high levels of paralytic shellfish poisoning (psp) toxins when fed the neurotoxic cyanobacterium anabaena circinalis, shown recently to contain high concentrations of c-toxins and gonyautoxins. significant accumulation (>80 mu g/100 g of mussel flesh) was detected following 2-3 exposure to water containing 2 x 105 cells/ml a. circinalis. only trace accumulation of psp toxins was demonstrated over long-term (5 week) exposure at low co ... | 1995 | 7660371 |
| molecular cloning of the cyanobacterial adenylate cyclase gene from the filamentous cyanobacterium anabaena cylindrica. | | 1995 | 7665507 |
| structure and replication of cryptic plasmids, pma1 and pma2, from a unicellular cyanobacterium, microcystis aeruginosa. | the 4993-bp cryptic plasmid, pma2, from a cyanobacterium, microcystis aeruginosa f. aeruginosa kützing, originally derived from kasumigaura lake, was completely sequenced and analyzed. plasmid pma2 had a unique sequence motif cttgatt, which was proposed to be a nicking site on the smaller plasmid pma1 (2287-bp) by the presence of single-stranded dna susceptible to s1 nuclease. we had detected the occurrence of the single-stranded pma1 in the living m. aeruginosa cells. this was also the case of ... | 1995 | 7670181 |
| occurrence of heme o in photoheterotrophically growing, semi-anaerobic cyanobacterium synechocystis sp. pcc6803. | extraction and identification of the non-covalently bound heme groups from crude membrane preparations of photoheterotrophically grown synechocystis sp. pcc 6803 by reversed phase high performance liquid chromatography and optical spectrophotometry led to the detection of heme o in addition to hemes b and a which latter was to be expected from the known presence of aa3-type cytochrome oxidase in cyanobacteria. in fully aerated cells (245 microm dissolved o2 in the medium) besides heme b only hem ... | 1995 | 7672130 |
| toxicity of microcystin-lr, isolated from microcystis aeruginosa, against various insect species. | microcystin-lr (mc-lr), isolated from the cyanobacterium microcystis aeruginosa kuetzing emend. elenkin strain ccap 1450/4 was tested for biological activity against four species of insect and the invertebrate artemia salina. the efficacy of pesticidal activity was compared with various insecticides. the 24 hr ld50 value for third instar diamond-backed moth, plutella xylostella, on ingestion from a treated leaf surface was 1.0 micrograms cm2, compared with a 72 hr ld50 value for rotenone of 2.0 ... | 1995 | 7676468 |
| characterization of ts-mutants of cyanophage n-1 by their inactivation by physical and chemical agents. | the effect of temperature, ultraviolet (uv) light and ethylenediaminetetraacetic acid (edta) on the stability of cyanophage n-1, infecting the cyanobacterium nostoc muscorum was studied. complete inactivation of the phage occurred at 60 degrees c in 6 mins. all the temperature-sensitive (ts) mutants exhibited faster inactivation at 50 degrees c than the wild type. uv light readily inactivated the particles of the wild giving a survival of 3.44% at a dose of 60 secs. all the ts-mutants were found ... | 1995 | 7676938 |
| the glna gene of the cyanobacterium agmenellum quadruplicatum pr-6 is nonessential for ammonium assimilation. | the glna gene of the cyanobacterium agmenellum quadruplicatum pr-6 (synechococcus sp. strain pcc 7002) was isolated by complementing an escherichia coli strain auxotrophic for glutamine (ymc11) with a pr-6 cosmid library. pr-6 glna is a single-copy gene that encodes a deduced amino acid sequence that is highly homologous to the deduced glna amino acid sequences reported for other bacteria. no homology was found between the pr-6 glna flanking sequences and the ntrb, ntrc, or glnb genes of other b ... | 1993 | 7678591 |
| a protein-tyrosine/serine phosphatase encoded by the genome of the cyanobacterium nostoc commune utex 584. | protein-tyrosine phosphorylation has long been regarded as an exclusively eukaryotic phenomenon. although some non-eukaryotes, mainly viruses, possess genes encoding protein-tyrosine kinases or protein-tyrosine phosphatases, these were probably appropriated from the eukaryotic hosts that constitute the sites of action of these enzymes. herein we identify a gene, iphp, from the chromosome of the cyanobacterium nostoc commune utex 584 that contains the his-cys-xaa-ala-gly-xaa-xaa-arg sequence char ... | 1993 | 7681825 |
| regulation of phycobilisome rod proteins and mrna at different light intensities in the cyanobacterium synechococcus 6301. | the regulation of the light-harvesting antennae, the phycobilisome (pbs), and the cpcb1a1-cpch-cpci-cpcd operon encoding the structural proteins of the pbs rod, was studied in the cyanobacterium, synechococcus sp. pcc 6301, when grown at different light intensities (li). pbs were purified and their linker protein (lp) profiles analyzed on sds-polyacrylamide gels. at increasing li, the amount of the distal 30-kda lp decreased prior to any change in the amount of the proximal 33-kda lp, indicating ... | 1993 | 7682531 |
| targeted inactivation of the gene psal encoding a subunit of photosystem i of the cyanobacterium synechocystis sp. pcc 6803. | photosystem i is a multisubunit pigment-protein complex that functions as a light-driven plastocyanin-ferredoxin oxidoreductase in thylakoid membranes of cyanobacteria and higher plants. a 16-kda protein subunit of photosystem i complex was isolated from the cyanobacterium synechocystis sp. pcc 6803. the sequence of its nh2-terminal residues was determined and a corresponding oligonucleotide probe was used to isolate the gene encoding this subunit. the gene, designated as psal, codes for a prote ... | 1993 | 7685019 |
| the genes aroa and trnq are located upstream of psbo in the chromosome of synechocystis 6803. | we have identified the existence of two genes, trnq and aroa, located upstream of the psbo gene in synechocystis sp. pcc 6803. the trnq gene encodes a glutamine-specific transfer rna (trna(gln)) and the sequence given is the first reported for any cyanobacterium. the gene seems to exist as a single copy since its deletion results in non-viable mutation. the aroa gene encodes for 5-enolpyruvylshikimate 3-phosphate synthase and its discovery in the genome of synechocystis 6803 is the first genetic ... | 1993 | 7686511 |
| effect of promoter modification on mosquitocidal cryivb gene expression in synechococcus sp. strain pcc 7942. | the impact of promoter modification on the expression of the mosquitocidal bacillus thuringiensis subsp. israelensis cryivb gene when used to transform the cyanobacterium synechococcus sp. strain pcc 7942 has been examined. maximal transcript and protein abundances were achieved by the addition of the lacz promoter upstream of the cryivb sequence. replacement of the endogenous corresponding bacillus sequences with the synechococcus petf1 promoter, ribosome binding site, and initiation codon also ... | 1993 | 7690220 |
| in situ detection of transcripts for ribulose-1,5-bisphosphate carboxylase in cyanobacterial heterocysts. | heterocysts of free-living cyanobacteria lack ribulose-1,5-bisphosphate carboxylase activity. nevertheless, using in situ hybridizations, we demonstrate that transcripts for the rbcl and rbcs genes are present in both heterocysts and vegetative cells of anabaena spp. in association with, or isolated from, the azolla-anabaena symbiosis. in contrast, rbcls transcripts were detected only in vegetative cells of the free-living cyanobacterium anabaena strain 7120. under anaerobic growth conditions th ... | 1993 | 7693657 |
| singular over-representation of an octameric palindrome, hip1, in dna from many cyanobacteria. | an octameric palindrome (5'-gcgatcgc-3') is abundant in cyanobacterial sequences within databases (genbank/embl) and was designated hip1 (highly iterated palindrome). the frequency of occurrence of all 256 octameric palindromes has now been determined in sub-databases revealing large and unique over-representation of hip1 in cyanobacterial entries. dna sequences from other bacteria were searched for any over-represented octameric palindromes analogous to hip1. only two sequences were identified, ... | 1995 | 7708486 |
| energy transfer and trapping in photosystem i reaction centers from cyanobacteria. | a mutant strain of the cyanobacterium synechocystis 6803, tole4b, was constructed by genetic deletion of the protein that links phycobilisomes to thylakoid membranes and of the cp43 and cp47 proteins of photosystem ii (psii), leaving the photosystem i (psi) center as the sole chromophore in the photosynthetic membranes. both intact membrane and detergent-isolated samples of psi were characterized by time-resolved and steady-state fluorescence methods. a decay component of approximately 25 ps dom ... | 1995 | 7708712 |
| a physical map of the genome of a unicellular cyanobacterium synechocystis sp. strain pcc6803. | an accurate physical map of the genome of a cyanobacterium, synechocystis sp. strain pcc6803, was constructed on the basis of restriction and linking clone analysis. the genome contained 6 recognition sites for asci, 25 sites for mlui, and 31 sites for spli, and the entire genome size was estimated to be 3.6 mb. sixteen genes or gene clusters, including those involved in the photosynthetic systems, were localized on the physical map of the genome by hybridization. in the course of the above anal ... | 1994 | 7719926 |
| [a new open reading frame in the genome of cyanobacteria synechocystis sp. pcc 6803]. | a new open reading frame orf242, coding for a 26.47-kda polypeptide, was found in a dna fragment of the cyanobacterium synechocystis 6803, transforming a photosynthetic mutant to photoautotrophy and having homology with plant chloroplast dna. in the 5' flanking region of orf242, consensus sequences characteristic of a functioning gene were found. one copy of orf242 is present in the synechocystis 6803 genome. insertion inactivation of orf242 does not lead to a decrease in photosynthetic activity ... | 1995 | 7721056 |
| functional analysis of the phosphoprotein pii (glnb gene product) in the cyanobacterium synechococcus sp. strain pcc 7942. | the pii protein (glnb gene product) in the cyanobacterium synechococcus sp. strain pcc 7942 signals the cellular n status by being phosphorylated or dephosphorylated at a seryl residue. here we show that the pii-modifying system responds to the activity of ammonium assimilation via the glutamine synthase-glutamate synthase pathway and to the state of co2 fixation. to identify possible functions of pii in this microorganism, a pii-deficient mutant was created and its general phenotype was charact ... | 1995 | 7721695 |
| structure of a novel oligosaccharide-mycosporine-amino acid ultraviolet a/b sunscreen pigment from the terrestrial cyanobacterium nostoc commune. | water-soluble uv-a/b-absorbing pigments are secreted by cells of the cosmopolitan terrestrial cyanobacterium nostoc commune. the pigments constitute a complex mixture of monomers with molecular masses of up to 1801 da. two different chromophores with absorption maxima at 312 and 335 nm are linked to different amino acids and to oligosaccharides consisting of galactose, glucose, xylose, glucuronic acid, and glucosamine. the 335 nm chromophore is a 1,3-diaminocyclohexen derivative, while the chrom ... | 1995 | 7721752 |
| purification and physicochemical properties of the low-potential cytochrome c549 from the cyanobacterium synechocystis sp. pcc 6803. | a soluble low-potential cytochrome c549 has been purified in milligram quantities from the cyanobacterium synechocystis sp. pcc 6803. the protein exhibits an acid isoelectric point of 3.9, a molecular mass of 15.8 kda, and a midpoint redox potential value of -250 mv at ph 7.0 epr and 1h nmr studies suggest a low-spin heme iron with bis-histidine coordination at the fifth and sixth positions. edta-photoreduced 5-deazariboflavin has been used as the electron-donating system to study, by laser flas ... | 1995 | 7726571 |
| isolation and spectroscopic characterization of a plantlike photosystem ii reaction center from the cyanobacterium synechocystis sp. 6803. | a chlorophyll-protein complex has been isolated from the cyanobacterium synechocystis sp. pcc 6803 that closely resembles higher plant photosystem ii reaction centers in spectral properties. the synechocystis complex has a pigment content of 5-7 chlorophyll a molecules:1 cyt b559:2 pheophytins; an optical absorption redmost transition at approximately 675 nm; and a nonconservative circular dichroism red signal, with extrema at 682 (+) and 652 (-) nm. upon illumination, the synechocystis d1/d2/cy ... | 1995 | 7727412 |
| amino acid residues that influence the binding of manganese or calcium to photosystem ii. 1. the lumenal interhelical domains of the d1 polypeptide. | to identify amino acid residues that ligate the manganese and calcium ions of photosystem ii or that are otherwise crucial to water oxidation, site-directed mutations were constructed in the unicellular cyanobacterium synechocystis sp. pcc 6803 at all conserved carboxylate, histidine, and tyrosine residues in the lumenal interhelical domains of the d1 polypeptide. mutants with impaired photoautotrophic growth or oxygen evolution were characterized in vivo by measuring changes in the yield of var ... | 1995 | 7727445 |
| amino acid residues that influence the binding of manganese or calcium to photosystem ii. 2. the carboxy-terminal domain of the d1 polypeptide. | to identify amino acid residues that ligate the manganese and calcium ions of photosystem ii or are otherwise crucial to water oxidation, site-directed mutations were constructed in the unicellular cyanobacterium synechocystis sp. pcc 6803 at all conserved carboxylate and histidine residues in the carboxy-terminal domain of the d1 polypeptide. mutants with impaired photoautotrophic growth or oxygen evolution were characterized in vivo by measuring changes in the yield of variable chlorophyll a f ... | 1995 | 7727446 |
| existence of two ferredoxin-glutamate synthases in the cyanobacterium synechocystis sp. pcc 6803. isolation and insertional inactivation of gltb and glts genes. | the first two genes of ferredoxin-dependent glutamate synthase (fd-gogat) from a prokaryotic organism, the cyanobacterium synechocystis sp. pcc 6803, were cloned in escherichia coli. partial sequencing of the cloned genomic dna, of the 6.3 kb hind iii and 9.3 kb cla i fragments, confirmed the existence of two different genes coding for glutamate synthases, named gltb and glts. the gltb gene was completely sequenced and encodes for a polypeptide of 1550 amino acid residues (m(r) 168,964). compara ... | 1995 | 7727752 |
| a protein is involved in accessibility of the inhibitor acetazolamide to the carbonic anhydrase(s) in the cyanobacterium synechocystis pcc 6803. | a gene, zam (for resistance to acetazolamide), controlling resistance to the carbonic anhydrase inhibitor acetazolamide, is described. it has been cloned from a spontaneous mutant, azar-5b, isolated from the cyanobacterium synechocystis pcc 6803, for its resistance to this drug (bédu et al., plant physiol 93: 1312-1315, 1990). this mutant, besides its resistance to acetazolamide, displayed an absence of catalysed oxygen exchange activity on whole cells, suggestive of a deficiency in carbonic anh ... | 1995 | 7727754 |
| electron transport controls transcription of the glutamine synthetase gene (glna) from the cyanobacterium synechocystis sp. pcc 6803. | the glna gene, encoding type i glutamine synthetase (gs) in synechocystis sp. pcc 6803, showed a high sequence similarity with other cyanobacterial glna genes. a dramatic decrease in the amount of glna mrna, a single transcript of about 1.6 kb, was observed after transfer to darkness, or after incubation with the electron transport inhibitors dcmu or dbmib. the levels of glna transcript were fully recovered after 5 min of reillumination. the glna mrna was found to be equally stable both in the l ... | 1995 | 7727755 |
| characterization of a zwf mutant of synechococcus sp. strain pcc 7942. | a mutant of the cyanobacterium synechococcus sp. strain pcc 7942 carrying a disrupted gene encoding glucose-6-phosphate dehydrogenase (zwf) produced no detectable glucose-6-phosphate dehydrogenase as assessed by enzyme assay and western blot (immunoblot) analysis. this mutant exhibited significantly impaired dark viability. | 1995 | 7730289 |
| a prokaryotic origin for light-dependent chlorophyll biosynthesis of plants. | flowering plants require light for chlorophyll synthesis. early studies indicated that the dependence on light for greening stemmed in part from the light-dependent reduction of the chlorophyll intermediate protochlorophyllide to the product chlorophyllide. light-dependent reduction of protochlorophyllide by flowering plants is contrasted by the ability of nonflowering plants, algae, and photosynthetic bacteria to reduce protochlorophyllide and, hence, synthesize (bacterio) chlorophyll in the da ... | 1995 | 7731978 |
| denaturing behavior of glutathione reductase from cyanobacterium spirulina maxima in guanidine hydrochloride. | the influence of guanidine hydrochloride (gdn-hcl) on glutathione reductase from spirulina maxima has been studied by measuring the changes in enzymatic activity, protein fluorescence, circular dichroism, thiol groups accessibility, and gel filtration chromatography. it was found that the denaturation process involves several intermediate states. at low, gdn-hcl concentrations (cm = 0.4 m), reductase activity was fully lost. however, below 3 m gdn-hcl, this inhibition was freely reversible upon ... | 1995 | 7733653 |
| occurrence of inosine kinase as a distinct enzyme in spirulina platensis. | among a series of purine nucleosides, inosine was found to be phosphorylated at the highest rate by crude extracts of the cyanobacterium spirulina platensis. the inosine phosphorylating activity could be separated from hypoxanthine-guanine phosphoribosyl transferase. this result shows that imp formation may occur via the direct phosphorylation of inosine at its 5'-position, rather than via inosine phosphorolysis, followed by hypoxanthine phosphoribosylation, and provides unequivocal evidence for ... | 1995 | 7733924 |
| molecular identification of an abc transporter complex for manganese: analysis of a cyanobacterial mutant strain impaired in the photosynthetic oxygen evolution process. | during photosynthesis, the photosystem ii (psii) pigment-protein complex catalyzes oxygen evolution, a reaction in which a four-manganese ensemble plays a crucial role. using a newly developed selection scheme, we have isolated bp13, a random photosynthesis-deficient mutant strain of the cyanobacterium, synechocystis 6803. this mutant grew slowly under photoautotrophic conditions, and had a low oxygen evolution activity. biochemical analysis revealed that the lesion in this mutant strain had spe ... | 1995 | 7743991 |
| protein hu from the cyanobacterium anabaena. | protein hu was purified from the cyanobacterium anabaena 7120. its complete amino acid sequence was determined by automated edman degradation of the whole protein and of cnbr and chymotryptic peptides. the active dna-binding protein is a homodimer of 94-amino acid subunits. approximately half of the residues are identical to those of the two subunits of hu protein from e. coli. the protein binds to both supercoiled and relaxed double-stranded dna, cooperatively. the contour lengths of circular d ... | 1994 | 7748931 |
| isolation and characterization of microcystins from laboratory cultures and environmental samples of microcystis aeruginosa and from an associated animal toxicosis. | six microcystins were identified in a laboratory culture of the cyanobacterium (blue-green alga) microcystis aeruginosa pcc 7813 using high-performance liquid chromatography coupled with diode array detection (hplc-dad) and mass spectrometry (lc-ms). the toxins were purified and further characterized by amino acid analysis and tandem mass spectrometry (ms-ms). the presence of the previously reported microcystin-lr and microcystin-ly was confirmed. two further microcystins were characterized as m ... | 1995 | 7749583 |
| involvement of the cp47 protein in stabilization and photoactivation of a functional water-oxidizing complex in the cyanobacterium synechocystis sp. pcc 6803. | oscillation patterns of the oxygen yield per flash induced by a train of single-turnover flashes were measured as a function of dark incubation and different pre-illumination conditions in several autotrophic mutant strains of synechocystis sp. pcc 6803 carrying short deletions within the large, lumen-exposed hydrophilic region (loop e) of the chlorophyll a-binding photosystem ii protein cp47. a physiological and biochemical characterization of these mutant strains has been presented previously ... | 1995 | 7756315 |
| structural organization of a cryptic plasmid, pma1, from microcystis aeruginosa f. aeruginosa kützing. | the 2287-bp cryptic plasmid, pma1, from microcystis aeruginosa f. aeruginosa kützing, a unicellular cyanobacterium originally derived from kasumigaura lake, was completely sequenced and analyzed. the predicted amino acid sequence (253 residues) of an open reading frame had identities of 47%, 48%, and 53% with replication-associated proteins of bacillus amyloliquefaciens's plasmid, pftb14, b. subtilis baa1's pbaa1, and b. coagulans's pbc1, respectively, when conservative amino acid substitutions ... | 1993 | 7764220 |
| a cyanobacterial gene encoding a protein with extensive homology to mammalian phosphoribosylpyrophosphate synthetase. | phosphoribosylpyrophosphate (pribpp) is the primary precursor in the biosynthesis of purine and pyrimidine nucleotides. the synthesis of pribpp is catalysed by a ubiquitous pribpp synthetase in many organisms. we provide evidence that a cyanobacterium, synechococcus sp., has a gene encoding a protein with striking homology to mammalian pribpp synthetases. | 1993 | 7764342 |
| foreign gene expression in marine cyanobacteria under pseudo-continuous culture. | foreign gene expression in a marine cyanobacterium, synechococcus nkbg 15041c, has been carried out in both batch and pseudo-continuous culture, using chloramphenicaol acetyltransferase (cat) as a model peptide and the broad host range vector pkt230. cat has been successfully expressed in marine cyanobacteria under kanamycin resistance gene promoter. pseudo-continuous culture of these recombinant marine cyanobacteria has been done by varying the dilution rate. at a dilution rate between 0.01 to ... | 1994 | 7764736 |
| growth of phormidium sp. in aerobic secondary piggery waste-water. | the potential of a cyanobacterium phormidium sp., for the tertiary treatment of piggery waste-water chemical oxygen demand > or = 3000 mg.l-1, using an aerobically stabilized secondary effluent, was studied. batch cultures were carried out in 2-l glass reactors and in a 30-l glass-fibre carousel reactor. the nutrient removal efficiency as well as biomass production were compared in synthetic mineral medium and in different concentrations of aerobically stabilized piggery effluent. the best perfo ... | 1994 | 7765784 |
| effect of ultraviolet-a (uv-a) light on growth, photosynthetic activity and production of biopterin glucoside by the marine uv-a resistant cyanobacterium oscillatoria sp. | we have isolated a marine planktonic cyanobacterium oscillatoria sp. nkbg 091600 which is resistant to ultraviolet-a (uv-a) irradiation. in response to uv-a irradiation this cyanobacterium produces high levels of a uv-a absorbing compound which was identified previously as biopterin glucoside. here, we have investigated the effect of uv-a light intensity on growth, biopterin glucoside production and photosynthetic activity. oscillatoria sp. nkbg 091600 could grow at uv-a intensities of up to 800 ... | 1995 | 7766653 |
| isolation, sequence and expression in escherichia coli of the nitrite reductase gene from the filamentous, thermophilic cyanobacterium phormidium laminosum. | the nitrite reductase (nir) gene (nira) has been isolated and sequenced from the filamentous, thermophilic non-n2-fixing cyanobacterium phormidium laminosum. putative promoter-like and shine-dalgarno sequences appear at the 5' end of the 1533 bp long nir-coding region. the deduced amino acid sequence of nir from p. laminosum corresponds to a 56 kda polypeptide, a size identical to the molecular mass previously determined for the pure enzyme, and shows a high identity with amino acid sequences fr ... | 1995 | 7766873 |
| multiple metal resistance in the cyanobacterium nostoc muscorum. | | 1995 | 7767039 |
| structure, function and regulation of the nitrate transport system of the cyanobacterium synechococcus sp. pcc7942. | the active nitrate transport system of the cyanobacterium synechococcus sp. pcc7942 is encoded by the four genes nrta, nrtb, nrtc and nrtd. it is essential for the growth of the cyanobacterium at physiological concentrations of nitrate and has been shown to be involved in the active transport of nitrite as well. the deduced amino acid sequences of the nrtb, nrtc and nrtd proteins indicate that the transporter is a member of the abc (atp-binding cassette) superfamily of active transporters. among ... | 1995 | 7767600 |
| amino acid transport systems required for diazotrophic growth in the cyanobacterium anabaena sp. strain pcc 7120. | uptake of 16 amino acids by the filamentous, heterocyst-forming cyanobacterium anabaena sp. strain pcc 7120 was characterized with regard to kinetic parameters of transport, intracellular accumulation of the transported amino acids, and sensitivity of the transport process to energy metabolism inhibitors. mutants resistant to certain toxic analogs of some amino acids were isolated that were impaired in amino acid transport. results obtained in this study, together with those reported previously ... | 1995 | 7768813 |
| disruption of a gene encoding a novel thioredoxin-like protein alters the cyanobacterial photosynthetic apparatus. | a gene that may encode a novel protein disulfide oxidoreductase, designated txla (thioredoxin-like), was isolated from the cyanobacterium synechococcus sp. strain pcc7942. interruption of txla near the putative thioredoxin-like active site yielded cells that grew too poorly to be analyzed. in contrast, a disruption of txla near the c terminus that left the thioredoxin-like domain intact yielded two different mutant phenotypes. one type, designated txlxb, exhibited a slightly reduced growth rate ... | 1995 | 7768827 |
| vectors for determining the differential expression of genes in heterocysts and vegetative cells of anabaena sp. strain pcc 7120. | plasmid vectors were constructed to study promoters of the cyanobacterium anabaena sp. strain pcc 7120. plasmid pccbselect contains the promoterless reporter genes in the order cat-nifhdk. in pccbselect/a, the nifhdk operon precedes the cat gene. putative promoter sequences were cloned into a polylinker region upstream of the reporter genes. activity in heterocysts was determined by complementation of a strain containing a deletion of the nifh gene. activity in vegetative cells was determined by ... | 1995 | 7768837 |
| physical and genetic map of the chromosome of the unicellular cyanobacterium synechocystis sp. strain pcc 6803. | a combined physical and genetic map of the cyanobacterium synechocystis sp. strain pcc 6803 chromosome was constructed. an estimated genome size of 3.82 mb was obtained by summing the sizes of 25 mlui or 40 noti fragments seen by pulsed-field electrophoresis. the order of the restriction fragments was determined by using two independent experimental approaches: pulsed-field fragment hybridization and linking clone analysis. the relative positions of 30 known genes or gene clusters were localized ... | 1995 | 7768838 |
| adp-ribosylation of glutamine synthetase in the cyanobacterium synechocystis sp. strain pcc 6803. | glutamine synthetase (gs) inactivation was observed in crude cell extracts and in the high-speed supernatant fraction from the cyanobacterium synechocystis sp. strain pcc 6803 following the addition of ammonium ions, glutamine, or glutamate. dialysis of the high-speed supernatant resulted in loss of inactivation activity, but this could be restored by the addition of nadh, nadph, or nadp+ and, to a lesser extent, nad+, suggesting that inactivation of gs involved adp-ribosylation. this form of mo ... | 1995 | 7768863 |
| nucleotide sequence of the staphylococcus aureus rna polymerase rpob gene and comparison of its predicted amino acid sequence with those of other bacteria. | the complete nucleotide sequence of the rpob gene which encodes the beta subunit of s. aureus rna polymerase has been determined. the rpob protein, consists of 1182 amino acids and has a novel initiation codon uug which initiates protein synthesis with methionine. there is a very strong shine-dalgarno complementarity and the -10 and -35 promoter hexameric sequences are taatat and ccgttt, respectively. a rho-dependent termination site, caatcaa, is present which overlaps the -35 promoter sequence ... | 1995 | 7772603 |
| inducible expression of heterologous genes targeted to a chromosomal platform in the cyanobacterium synechococcus sp. pcc 7942. | high-level, inducible expression of heterologous genes in the cyanobacterium synechococcus sp. strain pcc 7942 was obtained using the escherichia coli trc promoter and laci repressor. the pete gene of anabaena sp. strain pcc 7937 encoding plastocyanin precursor protein and the e. coli uida gene encoding beta-glucuronidase were initially placed under the control of the trc promoter and laci repressor by cloning into the e. coli ptrc99c expression vector and were introduced into the chromosomal pl ... | 1995 | 7773387 |
| inactivation of a synechocystis sp strain pcc 6803 gene with homology to conserved chloroplast open reading frame 184 increases the photosystem ii-to-photosystem i ratio. | a gene of the unicellular cyanobacterium synechocystis sp strain pcc 6803 that is homologous to the conserved chloroplast open reading frame orf184 has been cloned and sequenced. the nucleotide sequence of the gene predicts a protein of 184 amino acids with a calculated molecular mass of 21.5 kd and two membrane-spanning regions. amino acid sequence analysis showed 46 to 37% homology of the cyanobacterial orf184 with tobacco orf184, rice orf185, liverwort orf184, and euglena gracilis orf206 sequ ... | 1995 | 7780311 |
| luminometry and pcr-based monitoring of gene-tagged cyanobacteria in baltic sea microcosms. | the cyanobacterium synechocystis 6803 was tagged by chromosomal integration of the firefly luciferase gene, luc, resulting in the modified strain synechocystis 6803-luc. the tagged cells were monitored in baltic sea microcosms both by detection of the luc gene by pcr amplification and by measurement of luc gene expression (bioluminescence) in total protein extracted from sediment and water. a new method was developed for isolation and concentration of total protein from sediment for optimization ... | 1995 | 7781990 |
| isolation, crystallization, crystal structure analysis and refinement of allophycocyanin from the cyanobacterium spirulina platensis at 2.3 a resolution. | the phycobiliprotein allophycocyanin from the cyanobacterium spirulina platensis has been isolated and crystallized. the crystals belong to space group p6(3)22 with cell constants a = b = 101.9 a, c = 130.6 a, alpha = beta = 90 degrees, gamma = 120 degrees, with one (alpha beta) monomer in the asymmetric unit. the three-dimensional structure of the (alpha beta) monomer was solved by multiple isomorphous replacement. the crystal structure has been refined in a cyclic manner by energy-restrained c ... | 1995 | 7783202 |
| deconvolution of c-phycocyanin beta-84 and beta-155 chromophore absorption and fluorescence spectra of cyanobacterium mastigocladus laminosus. | absorption and fluorescence spectra of the c-phycocyanin beta-subunit were quantitatively deconvoluted into component spectra of the beta-84 and beta-155 chromophores. the deconvolution procedure was based on a theoretical treatment of polarization properties. four kinds of spectra (absorption, emission, emission polarization, and excitation polarization) measured on c-phycocyanin isolated from the cyanobacterium mastigocladus laminosus were used as the experimental data set. without any assumpt ... | 1995 | 7787035 |
| the nadp-glutamate dehydrogenase of the cyanobacterium synechocystis 6803: cloning, transcriptional analysis and disruption of the gdha gene. | the gdha gene of synechocystis pcc 6803, which encodes an nadp-dependent glutamate dehydrogenase (nadp-gdh), has been cloned by complementation of an escherichia coli glutamate auxotroph. this gene was found to code for a polypeptide of 428 amino acid residues, whose sequence shows high identity with those of archaebacteria (42-47%), some gram-positive bacteria (40-44%) and mammals (37%). the minimal fragment of synechocystis dna required for complementation (2kb) carries the gdha gene preceded ... | 1995 | 7787182 |
| purification and characterization of a synechococcus sp. strain pcc 7942 polypeptide structurally similar to the stress-induced dps/pexb protein of escherichia coli. | a stable dna/protein complex having an apparent molecular mass of approximately 150 kda was purified from nitrate-limited cultures of the cyanobacterium synechococcus sp. strain pcc 7942. amino-terminal peptide sequencing indicated that the polypeptide was structurally similar to the dps protein of escherichia coli; dps is also known as the product of the starvation- and stationary-phase-inducible gene, pexb. the 150-kda complex dissociated into a 22-kda protein monomer after boiling in 2% sds. ... | 1995 | 7794101 |
| deletion of the pest-like region of photosystem two modifies the qb-binding pocket but does not prevent rapid turnover of d1. | the rapid turn-over of the d1 polypeptide of the photosystem two complex has been suggested to be due to the presence of a "pest"-like sequence located between putative transmembrane helices iv and v of d1 (greenberg, b. m., gaba, v., mattoo, a. k. and edelman, m. (1987) embo j. 6, 2865-2869). we have tested this hypothesis by constructing a deletion mutant (delta 226-233) of the cyanobacterium synechocystis sp. pcc 6803 in which residues 226-233 of the d1 polypeptide, containing the pest-like s ... | 1995 | 7797471 |
| purification and amino- and carboxyl-terminal amino acid sequences of alanine-glyoxylate transaminase 1 from human liver. | in order to confirm the amino acid sequence predicted from the nucleotide sequence of cdna and also to elucidate the intracellular localization and molecular evolution, human liver alanine-glyoxylate transaminase 1 (agt1) was purified and subjected to partial amino acid sequence determination, with special attention to posttranslational modification. the enzyme was purified to homogeneity from the 10,000 x g supernatant of human liver homogenate. the purified enzyme showed only a single protein ... | 1994 | 7798168 |
| nucleotide sequence of the petb gene encoding cytochrome b6 from the mesophilic cyanobacterium synechocystis pcc 6803: implications for evolution and function. | the gene encoding the cytochrome b6 subunit (petb) of the cytochrome b6f complex has been isolated, cloned and sequenced by nonradioactive methods from genomic dna of the unicellular cyanobacterium synechocystis sp. pcc 6803. the coding region consists of 666 nucleotides, coding for a polypeptide with a molecular mass of 25.02 kda. in contrast to higher plant petb sequences an aminoterminal extension of seven amino acids occurs. aminoterminal sequencing of the isolated protein excludes--differen ... | 1994 | 7803459 |
| search for cyanobacterium-like bodies in the stools of travellers with diarrhoeal illness. | | 1994 | 7804258 |
| identification and characterization of two nitrogen-regulated genes of the cyanobacterium synechococcus sp. strain pcc7942 required for maximum efficiency of nitrogen assimilation. | two nitrogen-regulated genes were found in the genomic dna region upstream of the nira operon involved in uptake and utilization of nitrate in synechococcus sp. strain pcc7942. the two genes (nirb and ntcb) are transcribed divergently from nira and encode proteins of 349 and 309 amino acid residues, respectively. the levels of nirb and ntcb transcripts were low in cells growing on ammonium and increased upon transfer of ammonium-grown cells to nitrate-containing medium. the deduced nirb protein ... | 1995 | 7814317 |
| isl2, a new mobile genetic element in lactobacillus helveticus. | spontaneous, phenotypically stable mutations at the beta-galactosidase locus (lacl-lacm) in lactobacillus helveticus were identified and analyzed. we found that a significant number of mutations were caused by integration of a new is element, isl2, into these lac genes. isl2 is 858 bp long, flanked by 16-bp perfect inverted repeats and generates 3-bp target duplications upon insertion. it contains one open reading frame, which shows significant homology (40.1% identity) to the putative transposa ... | 1994 | 7816043 |
| supramolecular structure of the photosystem ii complex from green plants and cyanobacteria. | photosystem ii (psii) complexes, isolated from spinach and the thermophilic cyanobacterium synechococcus elongatus, were characterized by electron microscopy and single-particle image-averaging analyses. oxygen-evolving core complexes from spinach and synechococcus having molecular masses of about 450 kda and dimensions of approximately 17.2 x 9.7 nm showed twofold symmetry indicative of a dimeric organization. confirmation of this came from image analysis of oxygen-evolving monomeric cores of p ... | 1995 | 7816811 |
| cyanobacterial protein with similarity to the chlorophyll a/b binding proteins of higher plants: evolution and regulation. | we have isolated, from the prokaryotic cyanobacterium synechococcus sp. strain pcc 7942, a gene encoding a protein of 72 amino acids [designated high light inducible protein (hlip)] with similarity to the extended family of eukaryotic chlorophyll a/b binding proteins (cabs). hlip has a single membrane-spanning alpha-helix, whereas both the cabs and the related early light inducible proteins have three membrane-spanning helices. hence, hlip may represent an evolutionary progenitor of the eukaryot ... | 1995 | 7831342 |