| the cytochrome c oxidase genes in blue-green algae and characteristics of the deduced protein sequence for subunit ii of the thermophilic cyanobacterium synechococcus vulcanus. | blue-green algae (cyanobacteria) contain both primitive photosynthetic and respiratory systems in their membranes. the controversial genes coding for an alpha alpha 3-type cytochrome oxidase in cyanobacteria were examined. the dna probe coding for the most conserved part of subunit i hybridized with dna fragments from four cyanobacterial species. we have cloned the genes coding for subunits i and ii from the genomic library of the thermophilic cyanobacterium synechococcus vulcanus and determined ... | 1991 | 1659815 |
| insertional inactivation of the psbo gene encoding the manganese stabilizing protein of photosystem ii in the cyanobacterium synechococcus pcc7942. effect on photosynthetic water oxidation and l-amino acid oxidase activity. | a synechococcus pcc7942 mutant in which the psbo gene was inactivated by insertion of a chloramphenicol interposon and which did not contain any detectable manganese stabilizing protein in immunoblot experiments, was constructed. such a synechococcus mutant was able to grow under photoautotrophic conditions. isolated thylakoid membranes from the mutant required addition of cacl2 and mncl2 for photosynthetic o2 evolution, and the detectable l-amino acid oxidase activity in the isolated thylakoid ... | 1991 | 1660410 |
| a residue substitution in phosphoribulokinase of synechocystis pcc 6803 renders the mutant light-sensitive. | we have isolated a light-sensitive mutant (brls) of the photosynthetic cyanobacterium synechocystis 6803 (s. 6803) that does not survive exposure to bright light: 70% of brls cells die upon exposure to light of greater than 3,000 lux for 2 h. a complementing dna fragment from wild-type cells and the corresponding dna from the brls cells have been cloned and sequenced. an open reading frame is found to encode phosphoribulokinase, a key enzyme in the enzyme system for photosynthetic carbon reducti ... | 1991 | 1660882 |
| characterization of two insertion sequences, is701 and is702, from the cyanobacterium calothrix species pcc 7601. | we describe the characterization of two insertion elements, is701 and is702, isolated from calothrix species pcc 7601. these insertion elements were cloned from spontaneous pigmentation mutants. both show the characteristics of typical bacterial insertion sequences, i.e. they present long terminal inverted repeats and they duplicate target dna upon insertion. these elements share no homology with the only other cyanobacterial insertion sequence described so far, is891. at least 15 copies of is70 ... | 1991 | 1662761 |
| purification of ferredoxin-nadp+ reductase, flavodoxin and ferredoxin from a single batch of the cyanobacterium anabaena pcc 7119. | methods are described for the simultaneous isolation of ferredoxin-nadp+ reductase, ferredoxin and flavodoxin from large quantities of the cyanobacterium anabaena pcc 7119 allowing the use of a single batch of cells. the ultraviolet-visible spectra and the extinction coefficients of ferredoxin-nadp+ reductase and ferredoxin were determined. the purification procedure also yields enriched fractions of phycobiliproteins and cytochrome c553. | 1991 | 1664099 |
| molecular cloning of the genes encoding two chaperone proteins of the cyanobacterium synechocystis sp. pcc 6803. | molecular chaperones help other proteins in their correct folding and assembly. we have cloned the genes, cpn60 and dnak, which encode proteins belonging to the chaperonin-60 and the 70-kda heat shock protein families from the transformable cyanobacterium synechocystis sp. pcc 6803. these genes are present in single copies in the genome, and the major transcripts for each gene are monocistronic. comparison of deduced amino acid sequences reveals that cyanobacterial chaperonin-60 is equally homol ... | 1991 | 1670771 |
| regulation of glutamine synthetase activity in the unicellular cyanobacterium synechocystis sp. strain pcc 6803 by the nitrogen source: effect of ammonium. | glutamine synthetase activity from synechocystis sp. strain pcc 6803 is regulated as a function of the nitrogen source available in the medium. addition of 0.25 mm nh4cl to nitrate-grown cells promotes a clear short-term inactivation of glutamine synthetase, whose enzyme activity decreases to 5 to 10% of the initial value in 25 min. the intracellular levels of glutamine, determined under various conditions, taken together with the results obtained with azaserine (an inhibitor of transamidases), ... | 1991 | 1676397 |
| osmoregulatory role of alanine during salt stress in the nitrogen fixing cyanobacterium anabaena sp. 287. | the freshwater cyanobacterium, anabaena sp. 287 exhibited enhanced tolerance to nacl in the presence of ammonium, nitrate, and the amino acids, alanine, valine, proline, lysine, histidine, methionine and aspartic acid. apart from providing permanent protection to the growth during stress, like no3- and nh4+, alanine also relieved the initial salt mediated inhibition on enzymes involved in nitrogen fixation, photosynthesis and respiration. the accumulation of sugars was observed only during molec ... | 1991 | 1677806 |
| influence of different forms of nitrogen on uptake of ammonium, glutamate and glutamine in the cyanobacterium nostoc muscorum. | effect of various types of nitrogen nutrition was studied on the uptake of ammonium, glutamate and glutamine by nostoc muscorum and its het-nif- mutant. ammonium nitrogen acted as a potent inhibitor/repressor of ammonium, glutamate and glutamine transport. nitrate nitrogen was found to be a strong inhibitor/repressor of ammonium transport, a partial inhibitor/repressor of glutamate transport but, caused a partial stimulation of glutamine transport. | 1991 | 1684351 |
| evidence for a role of glutamine synthetase in assimilation of amino acids as nitrogen source in the cyanobacterium nostoc muscorum. | methylammonium/ammonium ion, glutamine, glutamate, arginine and proline uptake, and their assimilation as nitrogen sources, was studied in nostoc muscorum and its glutamine synthetase-deficient mutant. glutamine served as nitrogen source independent of glutamine synthetase activity. glutamate was not metabolised as a nitrogen source but still inhibited nitrogenase activity and diazotrophic growth. glutamine synthetase activity was essential for the assimilation of n2, ammonia, arginine and proli ... | 1991 | 1687107 |
| bacterial rna isolation with one hour centrifugation in a table-top ultracentrifuge. | a procedure for the rapid preparation of cesium-chloride purified rna from e. coli and the cyanobacterium synechococcus sp. pcc7942 is described. cells are lysed in modified sucrose, triton x-100, edta, tris buffer with phenol/chloroform. the cleared lysate is extracted further with phenol/chloroform and rna is peleted by centrifugation through a 5.7 m cscl cushion. high quality rna can be prepared in three hours using this procedure. | 1990 | 1691916 |
| characterization of the light-regulated operon encoding the phycoerythrin-associated linker proteins from the cyanobacterium fremyella diplosiphon. | many biological processes in photosynthetic organisms can be regulated by light quantity or light quality or both. a unique example of the effect of specific wavelengths of light on the composition of the photosynthetic apparatus occurs in cyanobacteria that undergo complementary chromatic adaptation. these organisms alter the composition of their light-harvesting organelle, the phycobilisome, and exhibit distinct morphological features as a function of the wavelength of incident light. fremyell ... | 1990 | 1694529 |
| genomic integration system based on pbr322 sequences for the cyanobacterium synechococcus sp. pcc7942: transfer of genes encoding plastocyanin and ferredoxin. | synechococcus sp. pcc7942 recipient strains were constructed for the chromosomal integration of dna fragments cloned in any pbr322-derived vector, which carries the ampicillin resistance (apr) marker. the construction was based on the incorporation of specific recombination targets, the so-called 'integration platforms', into the chromosomal metf gene. these platforms consist of an incomplete bla gene (aps) and the pbr322 ori separated from each other by a gene encoding an antibiotic (streptomyc ... | 1990 | 1701408 |
| characterization and mutagenesis of sulfur-regulated genes in a cyanobacterium: evidence for function in sulfate transport. | a sulfur-regulated gene (cysa) that encodes the membrane-associated atp-binding protein of the sulfate transport system of the cyanobacterium synechococcus sp. strain pcc 7942 was recently isolated and sequenced. adjacent to cysa and transcribed in the opposite direction is a gene encoding the sulfate-binding protein (sbpa). two other genes, cyst and cysw, encode proteins that may form a channel for the transport of sulfate across the cytoplasmic membrane. a fourth gene, cysr, located between cy ... | 1991 | 1708375 |
| isolation and characterization of a sulfur-regulated gene encoding a periplasmically localized protein with sequence similarity to rhodanese. | during sulfur-limited growth, the cyanobacterium synechococcus sp. strain pcc 7942 loses most of its photosynthetic pigments and develops an increased capacity to acquire sulfate. sulfur deprivation also triggers the synthesis of several soluble polypeptides. we have isolated a prominent polypeptide of 33 kda that accumulates specifically under sulfur-limiting conditions. this polypeptide was localized to the periplasmic space. the gene for this protein (designated rhda) was isolated and discove ... | 1991 | 1708376 |
| identification of a genomic region that complements a temperature-sensitive, high co2-requiring mutant of the cyanobacterium, synechococcus sp. pcc7942. | in a temperature-sensitive, high co2-requiring mutant of synechococcus sp. pcc7942, the ability to fix intracellularly accumulated inorganic carbon was severely impaired at non-permissive temperature (41 degrees c). in contrast, inorganic carbon uptake and ribulose-1.5-bisphosphate carboxylase activity in the mutant were comparable to the respective values obtained with the wild-type strain. the mutant was transformed to the wild-type phenotype (ability to form colonies at non-permissive tempera ... | 1991 | 1710016 |
| morphologic and staining characteristics of a cyanobacterium-like organism associated with diarrhea. | a spherical organism 9-10 microns in diameter, seen in three outbreaks of diarrhea in southeast asia and the united states during the past 2 years, bore characteristics of a cyanobacterium when observed in formalin-preserved stool specimens and by electron microscopy. organisms in freshly passed stool specimens showed an internal morula of lipid-containing globules. in fresh water, the morula divided into two sausage-shaped structures resembling the sporocysts of an isosporid coccidian. after 7 ... | 1991 | 1711553 |
| construction and characterization of cyanobacterial mutants lacking the manganese-stabilizing polypeptide of photosystem ii. | mutants of the cyanobacterium synechocystis sp. pasteur culture collection (pcc) 6803 that specifically lack the extrinsic 33-kda manganese-stabilizing polypeptide of the photosystem ii oxygen-evolving complex have been constructed by two independent methods. cartridge mutagenesis was used to insertionally inactivate the psbo gene of one mutant and completely delete the psbo gene of the other mutant. these mutants have no detectable manganese-stabilizing polypeptide, but they do accumulate stead ... | 1991 | 1712783 |
| photosynthetic electron transport controls degradation but not production of psba transcripts in the cyanobacterium synechocystis 6803. | accumulation and stability of psba and rbcl-s transcripts in synechocystis 6803 was followed in the presence and absence of the photosynthesis inhibitors dcmu and methylviologen. our results demonstrate that both transcript production and transcript stability are important regulatory elements for psba gene expression in synechocystis 6803. the production of psba transcripts was stimulated by light in a process that operated independently of the photosynthetic electron transport. however, stabili ... | 1991 | 1713480 |
| targeted genetic inactivation of the photosystem i reaction center in the cyanobacterium synechocystis sp. pcc 6803. | we describe the first complete segregation of a targeted inactivation of psaa encoding one of the p700-chlorophyll a apoproteins of photosystem (ps) i. a kanamycin resistance gene was used to interrupt the psaa gene in the unicellular cyanobacterium synechocystis sp. pcc 6803. selection of a fully segregated mutant, adk9, was performed under light-activated heterotrophic growth (lahg) conditions; complete darkness except for 5 min of light every 24 h and 5 mm glucose. under these conditions, wil ... | 1991 | 1717264 |
| an hsp70 homolog is encoded on the plastid genome of the red alga, porphyra umbilicalis. | a pcr experiment using porphyra umbilicalis dna as the template and degenerate oligonucleotides representing conserved regions of hsp70 amino acid sequences generated a 1 kb product that hybridized exclusively to the plastid dna of this red alga. dna sequencing of two contiguous ecori plastid dna clones revealed a 620 amino acid open reading frame with 71% identity to the dnak gene of the cyanobacterium, synechocystis 6803. northern hybridization experiments detected a 2.3 kb transcript that is ... | 1991 | 1720741 |
| purification and properties of nadp-isocitrate dehydrogenase from the unicellular cyanobacterium synechocystis sp. pcc 6803. | nadp-dependent isocitrate dehydrogenase activity has been screened in several cyanobacteria grown on different nitrogen sources; in all the strains tested isocitrate dehydrogenase activity levels were similar in cells grown either on ammonium or nitrate. the enzyme from the unicellular cyanobacterium synechocystis sp. pcc 6803 has been purified to electrophoretic homogeneity by a procedure that includes reactive-red-120-agarose affinity chromatography and phenyl-sepharose chromatography as main ... | 1992 | 1730247 |
| multiple evolutionary origins of prochlorophytes, the chlorophyll b-containing prokaryotes. | prochlorophytes are prokaryotes that carry out oxygenic photosynthesis using chlorophylls a and b, but lack phycobiliproteins as light-harvesting pigments. these characteristics distinguish them from cyanobacteria, which contain phycobiliproteins, but no chlorophyll b. three prochlorophyte genera have been described: prochloron, prochlorothrix and prochlorococcus. the prochlorophytes share their pigment characteristics with green plant and euglenoid chloroplasts, which has led to a debate on whe ... | 1992 | 1731224 |
| aspartate 170 of the photosystem ii reaction center polypeptide d1 is involved in the assembly of the oxygen-evolving manganese cluster. | eleven site-directed mutations were constructed at aspartate 170 of the d1 polypeptide of the photosystem ii (psii) reaction center of the cyanobacterium synechocystis sp. pcc 6803. the light-saturated rates of o2 evolution (vo2) measured in whole cells range from close to that of wild-type for asp170glu to zero for asp170ser and ala. those mutant strains that are best able to evolve o2 are also those that show the lowest km in psii core complexes for the oxidation of mn2+ by oxidized tyr161, th ... | 1992 | 1731951 |
| nucleotide sequence and expression of the ndhh gene of the cyanobacterium synechocystis sp. pcc6803. | | 1992 | 1731965 |
| cloning of a low-temperature-induced gene lti2 from the cyanobacterium anabaena variabilis m3 that is homologous to alpha-amylases. | a gene called lti2 which is induced by a shift to a low temperature was isolated from the cyanobacterium anabaena variabilis strain m3. this gene contained an open reading frame of 552 amino acid residues which exhibited homology to known alpha-amylases. the level of lti2 transcript increased 40-fold within an hour after a temperature shift from 38 to 22 degrees c and then slowly decreased to a low steady-state level. a less extensive expression of the lti2 gene is also induced by a temperature ... | 1992 | 1731972 |
| plastid dna from pyrenomonas salina (cryptophyceae): physical map, genes, and evolutionary implications. | cryptomonads are thought to have arisen from a symbiotic association between a eukaryotic flagellated host and a eukaryotic algal symbiont, presumably related to red algae. as organellar dnas have proven to be useful tools in elucidating phylogenetic relationships, the plastid (pt) dna of the cryptomonad alga pyrenomonas salina has been characterized in some detail. a restriction map of the circular 127 kb ptdna from pyrenomonas salina was established. an inverted repeat (ir) region of about 5 k ... | 1992 | 1735127 |
| glycinebetaine enhances and stabilizes the evolution of oxygen and the synthesis of atp by cyanobacterial thylakoid membranes. | glycinebetaine (betaine), an osmoregulant in halophilic plants, stabilized the evolution of oxygen and the synthesis of atp by thylakoid membranes from the cyanobacterium synechocystis pcc6803 when it was present during the preparation and incubation of the thylakoid membranes. moreover, betaine enhanced the evolution of oxygen and the synthesis of atp when present during assays. when betaine at 1.0 m was present during the preparation of thylakoid membranes and during the measurement of activit ... | 1991 | 1756870 |
| growth-phase-dependent induction of 6-phosphogluconate dehydrogenase and glucose 6-phosphate dehydrogenase in the cyanobacterium synechococcus sp. pcc7942. | in most cyanobacteria, the only known pathway for oxidation of stored carbohydrate in the dark or under energy-limiting conditions is the hexose monophosphate shunt. to determine whether the increased use of the shunt under these conditions derives from an increase in the activity level of the respective enzymes, we measured the effect of growth phase during the growth of batch cultures of synechococcus sp. strain pcc7942 on the specific activity of 6-phosphogluconate dehydrogenase (6pgd) and gl ... | 1991 | 1756984 |
| molecular evidence for the origin of plastids from a cyanobacterium-like ancestor. | the origin of plastids by either a single or multiple endosymbiotic event(s) and the nature of the progenitor(s) of plastids have been the subjects of much controversy. the sequence of the small subunit rrna (ssu rrna) from the plastid of the chlorophyll c-containing alga cryptomonas phi is presented, allowing for the first time a comparison of this molecule from all of the major land plant and algal lineages. using a distance matrix method, the phylogenetic relationships among representatives o ... | 1991 | 1757997 |
| oxidation-reduction potentials of ferredoxin-nadp+ reductase and flavodoxin from anabaena pcc 7119 and their electrostatic and covalent complexes. | the oxidation-reduction potentials of ferredoxin-nadp+ reductase and flavodoxin from the cyanobacterium anabaena pcc 7119 were determined by potentiometry. the potentials at ph 7 for the oxidized flavodoxin/flavodoxin semiquinone couple (e2) and the flavodoxin semiquinone/hydroquinone couple (e1) were -212 mv and -436 mv, respectively. e1 was independent of ph above about ph 7, but changed by approximately -60 mv/ph below about ph 6, suggesting that the fully reduced protein has a redox-linked p ... | 1991 | 1765067 |
| amplification, cloning, and sequencing of a nifh segment from aquatic microorganisms and natural communities. | by use of the polymerase chain reaction and degenerate oligonucleotide primers for highly conserved regions of nifh, a segment of nifh dna was amplified from several aquatic microorganisms, including an n2-fixing bacterium closely associated with the marine filamentous cyanobacterium trichodesmium sp., a heterotrophic isolate from the root/rhizome of the seagrass ruppia maritima, and the heterocystous freshwater cyanobacterium anabaena oscillarioides. nifh segments were amplified directly from d ... | 1991 | 1768139 |
| anatoxin-a(s), a naturally occurring organophosphate, is an irreversible active site-directed inhibitor of acetylcholinesterase (ec 3.1.1.7). | anatoxin-a(s) is a guanidine methyl phosphate ester (unprotonated molecular ion equals 252 daltons) isolated from the freshwater cyanobacterium (blue-green alga) anabaena flos-aquae strain nrc 525-17. previous work has shown anatoxin-a(s) to be a potent irreversible inhibitor of electric eel acetylcholinesterase (ec 3.1.1.7, ache). in the present study the interaction of anatoxin-a(s) with ache was investigated by protection studies and since similarities have been noted between anatoxin-a(s) an ... | 1991 | 1770503 |
| mutagenesis of the cyanobacterium spirulina platensis by uv and nitrosoguanidine treatment. | the production of spirulina platensis cells resistant to 8-azaguanine or beta-(2-thienyl)-dl-alanine following mutagenesis with n-methyl-n'-nitro-n-nitrosoguanidine (mnng) and uv-irradiation is described. the conditions for the mutagenesis were determined by monitoring cell viability and the appearance of the two types of mutants as a function of the stage of growth of the tricomes and the length and the conditions of the treatment. the optimal conditions for uv and mnng mutagenesis were found t ... | 1991 | 1778426 |
| inhibitory effect of petroleum oil on photosynthetic electron transport system in the cyanobacterium anabaena doliolum. | | 1991 | 1786460 |
| use of a mutant strain of the cyanobacterium synechococcus r2 for the determination of nitrate. | a sensitive procedure for the determination of nitrate within the 1- to 50-microm range is described. the method is based on the photoreduction of nitrate to nitrite by whole cells of a nitrite reductase-less mutant strain of the unicellular cyanobacterium synechococcus r2. cell suspensions of this cyanobacterium retain high levels of nitrate photoreduction activity for at least 2 months when maintained in the presence of dimethyl sulfoxide at -70 degrees c. | 1991 | 1789426 |
| studies on a toxin produced by the cyanobacterium phormidium persicinum. | | 1991 | 1794548 |
| [photocontrol of the synthesis of chlorophyll a and phycocyanin in the cyanobacterium calothrix crustacea schousboe]. | chlorophyll a and phycocyanin synthesis in the cyanobacterium calothrix crustacea schousboe (ecophene rivularia bullata) have been studied in white light after the application of red and green light pulses. the light quality produces a complementary pattern in the pigment synthesis. chlorophyll synthesis is stimulated by red light pulses whereas phycocyanin synthesis is by green light pulses. because the effect of red light on chlorophyll synthesis shows some far-red photoreversibility, the acti ... | 1991 | 1798852 |
| studies on glycolipids. iii. glyceroglycolipids from an axenically cultured cyanobacterium, phormidium tenue. | seven new monogalactosyl diacylglycerols (1-7) and six new digalactosyl diacylglycerols (11-16) were isolated from an axenically cultured cyanobacterium, p. tenue. their structures were elucidated on the basis of physicochemical evidence and the results of enzymatic hydrolysis using a lipase (from rhizopus arrhizus). comparison of antialgal activity for p. tenue between monogalactosyl diacylglycerols (1-8) and digalactosyl diacylglycerols (11-19) revealed that the former showed more potent activ ... | 1991 | 1804541 |
| evidence for energy-dependent copper efflux as a mechanism of cu2+ resistance in the cyanobacterium nostoc calcicola. | wild-type nostoc calcicola carried out oxygenic photosynthesis extremely sensitive to copper. a cu(2+)-resistant mutant (cu-r1) of the cyanobacterium grew normally at high concentrations of cu2+. its ability to grow under such conditions was found to be due to mutational acquisition of an energy-dependent efficient system of cu(2+)-efflux, which rendered cu(2+)-inhibited oxygenic photosynthesis fully reversible. | 1991 | 1804762 |
| molecular cloning and transcriptional analysis of the cpeba operon of the cyanobacterium pseudanabaena species pcc7409. | the cpeba operon of the group iii chromatically adapting cyanobacterium pseudanabaena species pcc 7409 was cloned, sequenced and characterized. the cpeba genes are transcribed in green-light-grown cells as an abundant 1400-nucleotide mrna which initiates 69 nucleotides upstream from the cpeb translation start. extensive sequence identity, extending 70 nucleotides 5' to the transcription start, occurs among cpeba promoters of group ii and iii chromatic adapters. cell extracts of green-light-grown ... | 1991 | 1809846 |
| amino acid sequence of the 8-kda protein in photosystem i reaction center complex from a thermophilic cyanobacterium, synechococcus elongatus. | the 8-kda protein in photosystem i (ps i) reaction center complex was isolated from a thermophilic cyanobacterium, synechococcus elongatus, by sds-polyacrylamide gel electrophoresis using tris-tricine buffer system. the complete amino acid sequence of the protein was determined. the 8-kda protein consisted of 73 amino acid residues giving a calculated molecular weight of 7,472. no significant sequence homology were observed with the known other small subunits in ps i reaction center complex, exc ... | 1991 | 1812486 |
| effects of dimethoate on n2-fixing cyanobacterium anabaena pcc 7119. | | 1991 | 1813092 |
| effect of lead on nitrogenase and enzymes of nitrogen assimilation in a cyanobacterium nostoc muscorum. | lead decreased the growth rates, total cell mass, heterocyst frequency, total cell protein, nitrogenase activity, glutamine synthetase (gs) and glutamate synthase (gogat) activities in n:muscorum. however, lead at 0.01 and 10 micrograms ml-1 conc. enhanced nitrogenase as well as gs activity of the cells. on transfer to excess lead (100 micrograms ml-1), nitrogenase and gs activities ceased almost after 24 hr in the cyanobacterium. it is deduced that lead has a two step effect on stimulation and ... | 1991 | 1816095 |
| [production of the antibiotic-algicide cyanobacterin lu-2 by a filamentous cyanobacterium nostoc sp]. | a strain of cyanobacterium of nostoc has been isolated, and found to produce a new antibiotic cyanobacterin lu-2. the antibiotic is synthesized by the cyanobnacterium under intensive cultivation conditions in a liquid mineral medium. cyanobacterin lu-2 is an exometabolite; its maximum accumulation in the medium is achieved at 34 degrees. cyanobacterin lu-2 is active against many cyanobacteria tested, including those of microcystis and aphanizomenon which are principals to give rise to blooms in ... | 1991 | 1819038 |
| the atp1 and atp2 operons of the cyanobacterium synechocystis sp. pcc 6803. | the two operons atp1 and atp2, encoding the subunits of the f0f1 atp-synthase, have been cloned and sequenced from the cyanobacterium synechocystis sp. pcc 6803. the organization of the different genes in the operons have been found to resemble that of the cyanobacteria synechococcus sp. pcc 6301 and anabaena sp. pcc 7120. the synechocystis f0f1 atp-synthase has nine subunits. a tenth open reading frame with unknown function was detected at the 5' end of atp1, coding for a putative gene product ... | 1991 | 1832989 |
| sequence-specific endonucleases from the cyanobacterium nostoc sp. atcc 29132. | the nitrogen-fixing cyanobacterium nostoc sp. atcc 29132 was shown to contain two sequence-specific endonucleases. nsp(29132) i was an isoschizomer of asuii, and nsp(29132) ii was an isoschizomer of bamhi. nsp(29132) ii was shown to generate ends that could be ligated to those generated by bamhi. | 1991 | 1840140 |
| characterization of a gene controlling heterocyst differentiation in the cyanobacterium anabaena 7120. | anabaena 7120 mutant 216 fails to differentiate heterocyst. we previously identified a 2.4-kb wild-type dna fragment able to complement this mutant. we show here that the sequence of this fragment contains a single open reading frame (hetr), encoding a 299-amino-acid protein. conjugation of deletion subclones of this fragment into strain 216 showed that the hetr-coding region is both necessary and sufficient for complementation of the het- phenotype. the mutation in 216 is located at nucleotide ... | 1991 | 1840555 |
| expression of a higher plant psba gene in synechocystis 6803 yields a functional hybrid photosystem ii reaction center complex. | the psba gene codes for the d1 polypeptide of the photosystem ii reaction center complex and is found in all photosynthetic organisms that carry out oxygenic photosynthesis. here we describe the construction and characterization of a strain of the cyanobacterium synechocystis sp pcc 6803 in which the three endogenous psba genes are replaced by a single psba gene from the chloroplast genome of the higher plant poa annua. the resulting chimeric strain, kwpas, grows photoautotrophically with a doub ... | 1991 | 1840918 |
| nitrogen ligation to manganese in the photosynthetic oxygen-evolving complex: continuous-wave and pulsed epr studies of photosystem ii particles containing 14n or 15n. | the possibility of nitrogen ligation to the mn in the oxygen-evolving complex from photosystem ii was investigated with electron paramagnetic resonance (epr) and electron spin echo envelope modulation (eseem) spectroscopies using 14n- and 15n-labeled preparations. oxygen-evolving preparations were isolated from a thermophilic cyanobacterium, synechococcus sp., grown on a medium containing either 14no3- or 15no3- as the sole source of nitrogen. the substructure on the "multiline" epr signal, whic ... | 1991 | 1846751 |
| epr characterization of an oxygen-evolving photosystem ii preparation from the transformable cyanobacterium synechocystis 6803. | the transformable cyanobacterium synechocystis 6803 has a photosynthetic apparatus that is similar to that of plants. because of the ease with which this organism can be genetically manipulated and isotopically labeled, synechocystis has been used extensively in recent studies of electron transfer in the water-splitting complex, photosystem ii. here, we present the first epr characterization of a highly active oxygen-evolving preparation from this organism. this preparation shows oxygen-evolutio ... | 1991 | 1850295 |
| sulfide-induced sulfide-quinone reductase activity in thylakoids of oscillatoria limnetica. | sulfide-dependent partial electron-transport reactions were studied in thylakoids isolated from cells of the cyanobacterium oscillatoria limnetica, which had been induced to perform sulfide-driven anoxygenic photosynthesis. it was found that these thylakoids have the capacity to catalyze electron transfer, from sulfide to externally added quinones, in the dark. assay conditions were developed to measure the reaction either as quinone-dependent sulfide oxidation (colorimetrically) or as sulfide-d ... | 1991 | 1898723 |
| deletion mutagenesis in synechocystis sp. pcc6803 indicates that the mn-stabilizing protein of photosystem ii is not essential for o2 evolution. | the photosystem ii (psii) reaction center complex coordinates a cluster of mn atoms that are involved in the accumulation of oxidizing equivalents generated by light-induced charge separations within the intrinsic portion of the psii complex. a 33-kda extrinsic protein, termed the mn-stabilizing protein (msp), has been implicated in the stabilization of two of the four mn atoms of the cluster, yet the precise role of this protein in o2 evolution remains to be elucidated. here we describe the con ... | 1991 | 1899025 |
| gene cluster rpobc1c2 in cyanobacteria does not constitute an operon. | the core enzyme of the cyanobacterial dna-dependent rna polymerase contains a unique component, gamma, which is absent from the corresponding enzymes of other eubacteria. in the heterocystous cyanobacterium nostoc commune the gene encoding gamma, rpoc1, is immediately adjacent to, and downstream of, rpob. the rpoc1 gene, and a 3' adjacent gene, rpoc2, correspond to the single rpoc gene found in escherichia coli with respect to those domains conserved within their translational products. northern ... | 1991 | 1899176 |
| isolation, crystallization, crystal structure analysis and refinement of constitutive c-phycocyanin from the chromatically adapting cyanobacterium fremyella diplosiphon at 1.66 a resolution. | constitutive phycocyanin from cyanobacterium fremyella diplosiphon (calothrix sp. pcc 7601) grown in green light, has been isolated and crystallized. the crystals belong to the space group r3 with cell constants a = b = 180.26 a, c = 61.24 a, alpha = beta = 90 degrees, gamma = 120 degrees. the crystal structure has been determined by patterson search techniques using the molecular model of c-phycocyanin from the cyanobacterium agmenellum quadruplicatum. the asymmetric unit of the crystal cell co ... | 1991 | 1899708 |
| a complex family of class-ii restriction endonucleases, dsai-vi, in dactylococcopsis salina. | a series of class-ii restriction endonucleases (enases) was discovered in the halophilic, phototrophic, gas-vacuolated cyanobacterium dactylococcopsis salina sp. nov. the six novel enzymes are characterized by the following recognition sequences and cut positions: 5'-c decreases crygg-3' (dsai); 5'-gg decreases cc-3' (dsaii); 5'-r decreases gatcy-3' (dsaiii); 5'-g decreases gwcc-3' (dsaiv); 5'-decreases ccngg-3' (dsav); and 5'-gtmkac-3' (dsavi), where w = a or t, m = a or c, k = g or t, and n = ... | 1991 | 1899848 |
| structural genes of glutamate 1-semialdehyde aminotransferase for porphyrin synthesis in a cyanobacterium and escherichia coli. | in bacteria 5-aminolevulinate, the universal precursor in the biosynthesis of the porphyrin nucleus of hemes, chlorophylls and bilins is synthesised by two different pathways: in non-sulphur purple bacteria (rhodobacter) or rhizobium 5-aminolevulinate synthase condenses glycine and succinyl-coa into 5-aminolevulinate as is the case in mammalian cells and yeast. in cyanobacteria, green and purple sulphur bacteria, as in chloroplasts of higher plants and algae a three step pathway converts glutama ... | 1991 | 1900346 |
| calcium-dependent protease of the cyanobacterium anabaena: molecular cloning and expression of the gene in escherichia coli, sequencing and site-directed mutagenesis. | it has been suggested that a calcium-dependent intracellular protease of the cyanobacterium, anabaena sp., participates in the differentiation of heterocysts, cells that are specialized for fixation of n2. clones of the structural gene (designated prca) for this protease from anabaena variabilis strain atcc 29413 and anabaena sp. strain pcc 7120 were identified via their expression in escherichia coli. the prca gene from a. variabilis was sequenced. the genes of both strains, mutated by insertio ... | 1991 | 1900347 |
| isolation and complementation of nitrogen fixation mutants of the cyanobacterium anabaena sp. strain pcc 7120. | approximately 140 mutants of anabaena sp. strain pcc 7120 unable to grow aerobically on media lacking fixed nitrogen (fix-) were isolated after mutagenesis with diethyl sulfate and penicillin enrichment. a large cosmid library of wild-type anabaena sp. strain pcc 7120 dna was constructed in a mini-rk-2 shuttle vector, and seven mutants representing several morphologically abnormal heterocyst phenotypes were complemented. one of these mutants, 216, failed to differentiate heterocysts. all of thes ... | 1991 | 1900504 |
| crystals of anabaena pcc 7119 ferredoxin-nadp+ reductase. | crystals of ferredoxin-nadp+ reductase (fnr) from the cyanobacterium anabaena pcc 7119 are grown in the presence of polyethylene glycol 6000 and beta-octyl glucoside. they belong to the hexagonal system. the cell parameters are a = b = 87.8 a, c = 92.7 a, space group p6(1) or p6(5), and a vm of 3.0 a3/dalton for one molecule of 36,000 daltons per asymmetric unit. these crystals diffract strongly up to 1.9 a and are suitable for x-ray structural studies. | 1991 | 1901362 |
| light-dependent de-activation/re-activation of anabaena variabilis ferredoxin: nadp+ reductase. | the activity of ferredoxin: nadp+ reductase (fnr) was found to decline to approximately 20% maximal levels with little or no loss in enzyme levels when cultures of the cyanobacterium anabaena variabilis were maintained in the stationary phase of growth. re-activation of enzyme activity occurred when cells were diluted into either fresh or re-utilized media and illuminated. this reversible de-activation/re-activation process was found, in vivo, to be dependent on the intensity of light illuminati ... | 1991 | 1901489 |
| isolation and characterization of the gene encoding the principal sigma factor of the vegetative cell rna polymerase from the cyanobacterium anabaena sp. strain pcc 7120. | the filamentous cyanobacterium anabaena sp. strain pcc 7120 responds to combined nitrogen deprivation by forming specialized nitrogen-fixing cells at regular intervals along the filament. genetic and biochemical studies have indicated that regulation of gene expression during differentiation occurs at the transcriptional level. as part of a characterization of rna polymerase during differentiation, the gene encoding the 52-kda principal sigma factor of the anabaena sp. strain pcc 7120 vegetative ... | 1991 | 1901566 |
| a vector for analysis of promoters in the cyanobacterium anabaena sp. strain pcc 7120. | a plasmid vector containing a multiple-cloning site followed by a promoterless chloramphenicol acetyltransferase (cat) gene, protected by transcription terminators and mobilizable by conjugation from escherichia coli into anabaena sp. strain pcc 7120, was constructed. the utility of the vector was shown by deletion analysis of the promoter region of the anabaena psbb gene. | 1991 | 1901575 |
| light-activated heterotrophic growth of the cyanobacterium synechocystis sp. strain pcc 6803: a blue-light-requiring process. | a glucose-tolerant strain of synechocystis sp. strain 6803 will not grow on glucose under complete darkness unless given a daily pulse of white light, typically 5 min of 40 mumol m-2 s-1 (light-pulsed conditions). the light pulse is insufficient for photoautotrophy, as glucose is required and growth yield is dependent on glucose concentration. growth rate is independent of fluence, but growth yield is dependent on fluence, saturating at 40 to 75 mumol m-2 s-1. a synechocystis strain 6803 psba mu ... | 1991 | 1902208 |
| absence of glycosylation on cyanobacterial phycobilisome linker polypeptides and rhodophytan phycoerythrins. | the 27-, 30-, and 33-kda rod linker polypeptides and the 75-kda core linker of phycobilisomes from the cyanobacterium synechococcus sp. strain pcc 7942 have been reported to be glycoproteins with carbohydrate contents ranging from 3.2 to 18.8% and composed of n-acetylgalactosamine and glucose (h.c. riethman, t.p. mawhinney, and l.a. sherman, j. bacteriol. 170:2433-2440, 1988). synechococcus sp. strain pcc 7942 phycobilisomes were purified extensively, and the linker polypeptides were separated f ... | 1991 | 1902214 |
| mutations in the small subunit of cyanobacterial ribulose-bisphosphate carboxylase/oxygenase that modulate interactions with large subunits. | in the cyanobacterium anacystis nidulans (synechococcus pcc6301), ribulose 1,5-bisphosphate carboxylase/oxygenase (rbu-p2 carboxylase) is composed of eight large subunits and eight small subunits. there are three regions of the small subunit that contain amino acids that are conserved throughout evolution, from bacteria to higher plants. since the function of the small subunit is not fully understood, site-directed mutagenesis was performed on highly conserved residues in the first and second co ... | 1991 | 1902220 |
| crystallization and structure determination to 2.5-a resolution of the oxidized [2fe-2s] ferredoxin isolated from anabaena 7120. | the molecular structure of the oxidized form of the [2fe-2s] ferredoxin isolated from the cyanobacterium anabaena species strain pcc 7120 has been determined by x-ray diffraction analysis to a nominal resolution of 2.5 a and refined to a crystallographic r factor of 18.7%. crystals used in this investigation belong to the space group p2(1)2(1)2(1) with unit cell dimensions of a = 37.42 a, b = 38.12 a, and c = 147.12 a and two molecules in the asymmetric unit. the three-dimensional structure of t ... | 1991 | 1902376 |
| a new photocatalytic material based on algal cells. | metallic platinum was deposited at surfaces of intracellular photosynthetic membranes of whole cells of a cyanobacterium (blue-green alga). the deposited platinum particles acted as a catalyst for generation of hydrogen from photosynthetic decomposition of water in the absence of other exogenous electron transfer agents. this technique represents a means of placing metal catalysts in contact with intracellular structures of microorganisms. | 1991 | 1902667 |
| the uptake of the cyanobacterial hepatotoxin microcystin by isolated rat hepatocytes. | microcystin-ym a cyclic heptapeptide hepatotoxin isolated from the cyanobacterium microcystis aeruginosa was radiolabeled with 125i, and used to investigate the uptake of the toxin by freshly isolated rat hepatocytes. the uptake was temperature dependent with apparent activation energy of 18 kcal/mole (77 kj/mole) for the initial rate of uptake. uptake of non-toxic (10-20 nm) doses of microcystin by hepatocytes continued with time, the intracellular to extracellular distribution ratio for the to ... | 1991 | 1903001 |
| pyruvate is a by-product of catalysis by ribulosebisphosphate carboxylase/oxygenase. | pyruvate is a minor product of the reaction catalyzed by ribulosebisphosphate carboxylase/oxygenase from spinach leaves. labeled pyruvate was detected, in addition to the major labeled product, 3-phosphoglycerate, when 14co2 was the substrate. pyruvate production was also measured spectrophotometrically in the presence of lactate dehydrogenase and nadh. the km for co2 of the pyruvate-producing activity was 12.5 microm, similar to the co2 affinity of the 3-phosphoglycerate-producing activity. no ... | 1991 | 1903385 |
| purification of glutamyl-trna reductase from synechocystis sp. pcc 6803. | delta-aminolevulinic acid is the universal precursor for all tetrapyrroles including hemes, chlorophylls, and bilins. in plants, algae, cyanobacteria, and many other bacteria, delta-aminolevulinic acid is synthesized from glutamate in a reaction sequence that requires three enzymes, atp, nadph, and trna(glu). the three enzymes have been characterized as glutamyl-trna synthetase, glutamyl-trna reductase, and glutamate-1-semialdehyde aminotransferase. all three enzymes have been separated and part ... | 1991 | 1903397 |
| deletion of the psbg1 gene of the cyanobacterium synechocystis sp. pcc6803 leads to the activation of the cryptic psbg2 gene. | the genes psbg1 and psbg2 in the cyanobacterium synechocystis sp. pcc6803 are homologous. the psbg1 gene is located on the chromosome and is part of the ndhc--psbg1--orf157 operon, while psbg2 is located on a plasmid and is not flanked by equivalent ndhc or orf157 genes. mutants in which psbg1 is deleted grow well under autotrophic conditions, while their growth is impeded in mixotrophic medium. these results argue against a functional role for psbg1 in photosynthesis, i.e. photosystem ii, and a ... | 1991 | 1903500 |
| cyanobacterial thylakoid membrane proteins are reversibly phosphorylated under plastoquinone-reducing conditions in vitro. | reversible, light-dependent protein phosphorylation was observed in isolated thylakoid membranes of the cyanobacterium synechococcus 6301. a polypeptide of 15 kda in particular was phosphorylated under plastoquinone-reducing conditions and was not phosphorylated under plastoquinone-oxidising conditions. phosphorylation and dephosphorylation reactions involving this and several other membrane polypeptides showed sensitivity to inhibitors of protein kinases and phosphatases. changes in phosphoryla ... | 1991 | 1903715 |
| carotenoid composition in the cyanobacterium phormidium laminosum. effect of nitrogen starvation. | when pigments of the non-n2-fixing cyanobacterium phormidium laminosum were carefully extracted and analyzed in a completely o2-free atmosphere, by either high performance liquid chromatography (hplc) or thin layer chromatography (tlc), the presence of only two carotenoids (namely, beta-carotene and nostoxanthin) was detected. however, exposure of pigments to an air atmosphere during their manipulation led to the rapid appearance in the organic extracts of at least three additional carotenoids ( ... | 1991 | 1903716 |
| cloning of the psbk gene from synechocystis sp. pcc 6803 and characterization of photosystem ii in mutants lacking psii-k. | we cloned and sequenced the psbk gene, coding for a small photosystem ii component (psii-k), from the transformable cyanobacterium, synechocystis sp. pcc 6803, and determined the n-terminal sequence of mature psii-k. the psbk gene product is processed by cleaving off eight amino acid residues from the n terminus. a mutant lacking psbk was constructed; this mutant grew photoautotrophically, but its growth rate was reduced. the number of photosystem ii reaction centers on a chlorophyll basis was d ... | 1991 | 1904061 |
| evolutionary relationships among eubacteria, cyanobacteria, and chloroplasts: evidence from the rpoc1 gene of anabaena sp. strain pcc 7120. | rna polymerases of cyanobacteria contain a novel core subunit, gamma, which is absent from the rna polymerases of other eubacteria. the genes encoding the three largest subunits of rna polymerase, including gamma, have been isolated from the cyanobacterium anabaena sp. strain pcc 7120. the genes are linked in the order rpob, rpoc1, rpoc2 and encode the beta, gamma, and beta' subunits, respectively. these genes are analogous to the rpobc operon of escherichia coli, but the functions of rpoc have ... | 1991 | 1904436 |
| gas vesicle synthesis in the cyanobacterium pseudanabaena sp.: occurrence of a single photoregulated gene. | gas vesicles are subcellular inclusions found in a large number of aquatic prokaryotes. the gvpa gene, which frequently occurs as a multigene family, encodes the major gas vesicle structural protein. in several cyanobacteria, another gene, gvpc, encodes a different protein which might be a dispensable element for gas vesicle formation. we report here the molecular characterization of a gvpa gene in pseudanabaena sp. pcc 6901. in this planktonic cyanobacterium, it is the only gvp gene which could ... | 1991 | 1904525 |
| a neurotoxic factor associated with the bloom-forming cyanobacterium trichodesmium. | | 1991 | 1904659 |
| alterations in the accumulation of adenylylated nucleotides in heavy-metal-ion-stressed and heat-stressed synechococcus sp. strain pcc 6301, a cyanobacterium, in light and dark. | heavy-metal-ion- (cd2+, cu2+, pb2+, hg2+ and zn2+) or heat (50 degrees c)-stress treatments of the unicellular cyanobacterium synechococcus sp., strain pcc 6301, under both light and dark conditions led to the accumulation of bis(5'-nucleosidyl)oligophosphates: ap4a, ap4g, ap3a, ap3g and ap3gp2. under light regimens, the accumulation of ap4a and ap4g is more characteristic of heavy-metal-ion-stressed cells, whereas the accumulation of ap3a, ap3g and ap3gp2 is the dominant feature of heavy-metal- ... | 1991 | 1904720 |
| site directed mutagenesis of the heme axial ligands of cytochrome b559 affects the stability of the photosystem ii complex. | cytochrome (cyt) b559, an integral membrane protein, is an essential component of the photosystem ii (psii) complex in the thylakoid membranes of oxygenic photosynthetic organisms. cyt b559 has two subunits, alpha and beta, each with one predicted membrane spanning alpha-helical domain. the heme cofactor of this cytochrome is coordinated between two histidine residues. each of the two subunit polypeptides of cyt b559 has one his residue. to investigate the influence of these his residues on the ... | 1991 | 1904816 |
| photosynthetic electron transport controls nitrogen assimilation in cyanobacteria by means of posttranslational modification of the glnb gene product. | a glnb gene is identified in the cyanobacterium synechococcus sp. pcc 7942, and its gene product is found to be covalently modified as a result of imbalance in electron transfer in photosynthesis, where photosystem ii is favored over photosystem i. the gene was cloned and sequenced and found to encode a polypeptide of 112 amino acid residues, whose sequence shows a high degree of similarity to the escherichia coli regulatory protein, pii. in e. coli, pii is involved in signal transduction in tra ... | 1991 | 1905010 |
| monomeric and trimeric forms of photosystem i reaction center of mastigocladus laminosus: crystallization and preliminary characterization. | photosystem i (psi) reaction centers (rcs) of the thermophilic cyanobacterium mastigocladus laminosus were purified and characterized. the psi rc was obtained in two forms, monomeric and trimeric. the two forms contained the same number of pigments per p700 and displayed similar photochemical activities. the two forms had nearly identical polypeptide subunit compositions; the only observed difference was an additional subunit of about 12 kda observed in the trimeric form. the purified preparatio ... | 1991 | 1905020 |
| fine-structural and chemical analyses on inner and outer sheath of the cyanobacterium gloeothece sp. pcc 6909. | cells of the unicellular cyanobacterium gloeothece sp. pcc 6909 are surrounded by an inner (enclosing 1-2 cells) and an outer (enclosing cell groups) sheath. using conventional epon-embedding in combination with ruthenium-red staining, the inner and outer sheaths appeared similar and displayed multiple bands of electron-dense subunits. however, embedding in nanoplast resin to avoid shrinkage led to the detection of two distinct zones (inner and outer zone) each with several distinct layers. the ... | 1991 | 1905514 |
| oxidative stress responses in the unicellular cyanobacterium synechococcus pcc 7942. | oxidative stress responses were tested in the unicellular cyanobacterium synechococcus pcc 7942 (r-2). cells were exposed to hydrogen peroxide, cumene hydroperoxide and high light intensities. the extent and time course of oxidative stress were related to the activities of ascorbate peroxidase and catalase. ascorbate peroxidase was found to be the major enzyme involved in the removal of hydrogen peroxide under the tested oxidative stress. catalase activity was inhibited in cells, treated with hi ... | 1991 | 1905671 |
| an nad-specific glutamate dehydrogenase from cyanobacteria. identification and properties. | the unicellular cyanobacterium synechocystis sp. pcc 6803 presents a hexameric nad-specific glutamate dehydrogenase with a molecular mass of 295 kda. the enzyme differs from the nadp-glutamate dehydrogenase found in the same strain and is coded by a different gene. nad-glutamate dehydrogenase shows a high coenzyme specificity, catalyzes preferentially glutamate formation and presents km values for ammonium, nadh and 2-oxoglutarate of 4.5 mm, 50 microm and 1.8 mm respectively. an animating role f ... | 1991 | 1906012 |
| the molecular basis of resistance to the herbicide norflurazon. | we have cloned and sequenced a gene, pds, from the cyanobacterium synechococcus pcc7942 that is responsible for resistance to the bleaching herbicide norflurazon. a point mutation in that gene, leading to an amino acid substitution from valine to glycine in its polypeptide product, was found to confer this resistance. previous studies with herbicide-resistant mutants have indicated that this gene encodes phytoene desaturase (pds), a key enzyme in the biosynthesis of carotenoids. a short amino ac ... | 1991 | 1907510 |
| primary structure of the psbn-psbh-petc-peta gene cluster of the cyanobacterium synechocystis pcc 6803. | | 1991 | 1907512 |
| cyanobacteria contain a mitochondrial complex i-homologous nadh-dehydrogenase. | thylakoid and cytoplasmic membranes of the cyanobacterium synechocystis sp. pcc 6803 were purified by sucrose gradient centrifugation. both membranes oxidize nadh in a rotenone-sensitive reaction. antibodies prepared against psbg/ndhk and ndhj fusion proteins detect the corresponding polypeptides in both membrane preparations. this demonstrates that a nadh-dehydrogenase, homologous to the mitochondrial nadh-ubiquinone-oxidoreductase (complex i of the respiratory chain) is present in cyanobacteri ... | 1991 | 1907569 |
| partial conservation of the 5' ndhe-psac-ndhd 3' gene arrangement of chloroplasts in the cyanobacterium synechocystis sp. pcc 6803: implications for ndh-d function in cyanobacteria and chloroplasts. | the psac gene, which encodes the 8.9 kda iron-sulfur containing subunit of photosystem i, has been sequenced from synechocystis sp. pcc 6803 and shows greater similarity to reported plant sequences than other cyanobacterial psac sequences. the deduced amino acid sequence of the protein encoded by the synechocystis psac gene is identical to the tobacco psa-c sequence. in plants psac is located in the small single-copy region of the chloroplast genome between two genes (designated ndhe and ndhd) w ... | 1991 | 1907869 |
| identities of four low-molecular-mass subunits of the photosystem i complex from anabaena variabilis atcc 29413. evidence for the presence of the psai gene product in a cyanobacterial complex. | photosystem i (psi) complex of anabaena variabilis atcc 29413 consists of at least 11 subunits, 9 of which are resolved by high resolution gel electrophoresis. n-terminal amino acid sequences of the four subunits with molecular masses of 6.8, 5.2, 4.8 and 3.5 kda were determined. based on the sequence homology, the 3.5 kda subunit was revealed to correspond to psi-i (the gene product of psai), which had so far been detected only in higher plant psi complexes. the 6.8 kda protein and 4.8 kda prot ... | 1991 | 1908790 |
| interactive image analysis system to determine the motility and velocity of cyanobacterial filaments. | an interactive image analysis system has been developed to analyse and quantify the percentage of motile filaments and the individual linear velocities of organisms. the technique is based on the "difference" image between two digitized images taken from a time-lapse video recording 80 s apart which is overlaid on the first image. the bright lines in the difference image represent the paths along which the filaments have moved and are measured using a crosshair cursor controlled by the mouse. ev ... | 1991 | 1908871 |
| energy transfer kinetics in c-phycocyanin from cyanobacterium westiellopsis prolifica studied by pump-probe techniques. | the relaxation processes of c-phycocyanin at different aggregates have been investigated by pump-probe techniques. the lifetimes of ground state recovery measured at various wavelengths are analyzed by computer fitting of the kinetic data to a sum of three and four exponentials for monomers and trimers according to the nonlinear least-square principle, respectively. the shortest lifetime (about 56ps) is due to beta s----beta f transfer in one monomer, that decreases to 31ps in trimer due to the ... | 1991 | 1909122 |
| interaction of ferredoxin-nadp+ reductase from anabaena with its substrates. | the interaction of ferredoxin-nadp+ reductase from the cyanobacterium anabaena variabilis with its substrates, nadp+ and ferredoxin, has been studied by difference absorption spectroscopy. several structural analogs of nadp+ have been shown to form complexes the stabilities of which are strongly dependent on the ionic strength of the medium. in most cases the binding energy of these complexes and their difference absorption spectra are similar to those reported for the spinach enzyme. however, n ... | 1991 | 1910307 |
| separation and partial characterization of enzymes catalyzing delta-aminolevulinic acid formation in synechocystis sp. pcc 6803. | formation of the universal tetrapyrrole precursor, delta-aminolevulinic acid (ala), from glutamate via the five-carbon pathway requires three enzymes: glutamyl-trna synthetase, glutamyl-trna reductase, and glutamate-1-semialdehyde (gsa) aminotransferase. all three enzymes were separated from extracts of the unicellular cyanobacterium synechocystis sp. pcc 6803, and two of them, glutamyl-trna synthetase and gsa aminotransferase, were partially characterized. after an initial high speed centrifuga ... | 1991 | 1910318 |
| cloning and sequence analysis of the phycocyanin genes of the marine cyanobacterium synechococcus sp. wh7803. | | 1991 | 1912508 |
| uptake and subcellular localization of tritiated dihydro-microcystin-lr in rat liver. | microcystin-lr (mc-lr), a cyclic heptapeptide hepatotoxin (mol. wt = 994) produced by the blue-green alga (cyanobacterium), microcystis aeruginosa, was reduced with tritium labeled sodium borohydride, converted to [3h]-dihydro-microcystin-lr ( [3h]-2hmc-lr), and purified to greater than 99% purity by c-18 reverse-phase high-performance liquid chromatography. the uptake and subcellular distribution of [3h]-2hmc-lr were determined in suspensions of hepatocytes at 0 degrees c and 37 degrees c, or f ... | 1991 | 1926162 |
| the amino-acid sequence of three proteins of photosystem i of the cyanobacterium fremyella diplosiphon (calothrix sp pcc 7601). | three proteins containing 138 amino acids (psad protein), 80 amino acids (psac protein) and 66 amino acids (psae protein) of the photosystem i (ps i) complex of the cyanobacterium fremyella diplosiphon (calothrix sp pcc 7601) were isolated and sequenced. comparison with previously known sequences showed a close relationship to homologous proteins of nostoc, another filamentous cyanobacterium. | 1991 | 1930733 |
| expression of photosynthesis genes in the cyanobacterium synechocystis sp. pcc 6803: psaa-psab and psba transcripts accumulate in dark-grown cells. | we have cloned and sequenced the psaa and psab genes from the unicellular cyanobacterium synechocystis sp. pcc 6803. these genes are arranged in tandem, are co-transcribed, and are highly homologous to the psaa and psab genes previously characterized. rna was isolated from light-grown cells, from cells put in total darkness with and without glucose, and from cells grown under light-activated heterotrophic growth (lahg) conditions. quantitation of hybridization to northern blots revealed only a s ... | 1991 | 1932686 |
| oligonucleotide-directed mutagenesis of psbb, the gene encoding cp47, employing a deletion mutant strain of the cyanobacterium synechocystis sp. pcc 6803. | a mutant strain of the cyanobacterium synechocystis sp. pcc (pasteur culture collection) 6803 has been developed in which psbb, the gene coding for the chlorophyl alpha-binding protein cp47 in photosystem ii (psii), has been deleted. this deletion mutant can be used for the reintroduction of modified psbb into the cyanobacterium. to study the role of a large hydrophilic region in cp47, presumably located on the lumenal side of the thylakoid membrane between the fifth and sixth membrane-spanning ... | 1991 | 1932693 |
| promoter recognition by the rna polymerase from vegetative cells of the cyanobacterium anabaena 7120. | the transcription start points (tsp) of seven genes of anabaena 7120 were previously identified by s1 nuclease protection and primer extension experiments using rna extracted from cells. in the present work, these tsp were confirmed, with one exception, by in vitro transcription using purified rna polymerases of anabaena 7120 and escherichia coli, and crude extracts of anabaena 7120 active in transcription. in all cases, the template for transcription consisted of closed circular plasmid dna in ... | 1991 | 1937007 |