Publications

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
neutralization of microcystin shock in mice by tumor necrosis factor alpha antiserum.	microcystis aeruginosa is a common cyanobacterium in water blooms that appear widely in nutrient-rich, fresh, and brackish waters, and its toxic blooms cause the death of domestic animals. the administration of a crude toxic cell extract of m. aeruginosa k-139 to mice can produce tumor necrosis factor (tnf) and prompt severe physiological disturbances, especially liver damage, which can lead to death. the in vitro production of tnf-alpha by peritoneal macrophages was observed after stimulation w ...	1991	2036020
effect of light quality on phycobilisome components of the cyanobacterium spirulina platensis.	phycobilisomes from the nonchromatic adapting cyanobacterium spirulina platensis are composed of a central core containing allophycocyanin and rods with phycocyanin and linker polypeptides in a regular array. room temperature absorption spectra of phycobilisomes from this organism indicated the presence of phycocyanin and allophycocyanin. however, low temperature absorption spectra showed the association of a phycobiliviolin type of chromophore within phycobilisomes. this chromophore had an abso ...	1991	16668011
purification and characterization of phosphoglycolate phosphatase from the cyanobacterium coccochloris peniocystis.	the properties and role of the enzyme phosphoglycolate phosphatase in the cyanobacterium coccochloris peniocystis have been investigated. phosphoglycolate phosphatase was purified 92-fold and had a native molecular mass of approximately 56 kilodaltons. the enzyme demonstrated a broad ph optimum of ph 5.0 to 7.5 and showed a relatively low apparent affinity for substrate (k(m) = 222 micromolar) when compared to that from higher plants. the enzyme required both an anion and divalent cation for act ...	1991	16668041
control of nitrogenase mrna levels by products of nitrate assimilation in the cyanobacterium anabaena sp. strain pcc 7120.	nitrate inhibited nitrogenase synthesis and heterocyst development in the cyanobacterium anabaena sp. strain pcc 7120. inhibition of dinitrogen fixation by nitrate did not take place, however, in nitrate reductase-deficient derivatives of this strain. hybridization of total rna isolated from cells grown on different nitrogen sources with an internal fragment of the nifd gene showed that regulation of nitrogenase activity by nitrate is exerted through a negative control of the nitrogenase mrna le ...	1991	16668475
high affinity transport of co(2) in the cyanobacterium synechococcus utex 625.	the active transport of co(2) in synechococcus utex 625 was measured by mass spectrometry under conditions that preclude hco(3) (-) transport. the substrate concentration required to give one half the maximum rate for whole cell co(2) transport was determined to be 0.4 +/- 0.2 micromolar (mean +/- standard deviation; n = 7) with a range between 0.2 and 0.66 micromolar. the maximum rates of co(2) transport ranged between 400 and 735 micromoles per milligram of chlorophyll per hour with an average ...	1991	16668535
use of ultrafiltration to isolate viruses from seawater which are pathogens of marine phytoplankton.	viruses may be major structuring elements of phytoplankton communities and hence important regulators of nutrient and energy fluxes in aquatic environments. in order to ascertain whether viruses are potentially important in dictating phytoplankton community structure, it is essential to determine the extent to which representative phytoplankton taxa are susceptible to viral infection. we used a spiral ultrafiltration cartridge (30,000-molecular-weight cutoff) to concentrate viruses from seawater ...	1991	16348439
chemical characterization of polysaccharide from the slime layer of the cyanobacterium microcystis flos-aquae c3-40.	macromolecular material from the slime layer of the cyanobacterium microcystis flos-aquae c3-40 was defined as material that adhered to cells during centrifugation in growth medium but was dislodged by washing with deionized water and retained within dialysis tubing with a molecular-weight cutoff of 3,500. at each step of this isolation procedure, the slime was observed microscopically. cells in the centrifugal pellet were surrounded by large amounts of slime that excluded negative stain, wherea ...	1991	16348506
photosynthetic carbon incorporation and turnover in antarctic cryptoendolithic microbial communities: are they the slowest-growing communities on earth?	the main forms of terrestrial life in the cold, desolate ross desert of antarctica are lichen-dominated or cyanobacterium-dominated cryptoendolithic (hidden in rock) microbial communities. though microbial community biomass (as measured by extractable lipid phosphate) was well within the range of values determined for other microbial communities, community lipid carbon turnover times (calculated from community lipid biomass, rates of community photosynthetic carbon incorporation into lipids vers ...	1991	16348539
contemporaneous n(2) fixation and oxygenic photosynthesis in the nonheterocystous mat-forming cyanobacterium lyngbya aestuarii.	the nonheterocystous filamentous cyanobacterial genus lyngbya is a widespread and frequently dominant component of marine microbial mats. it is suspected of contributing to relatively high rates of n(2) fixation associated with mats. the ability to contemporaneously conduct o(2)-sensitive n(2) fixation and oxygenic photosynthesis was investigated in lyngbya aestuarii isolates from a north carolina intertidal mat. short-term (<4-h) additions of the photosystem ii (o(2) evolution) inhibitor 3(3,4- ...	1991	16348576
major role of the cyanobacterium trichodesmium in nutrient cycling in the north atlantic ocean.	the diazotrophic cyanobacterium trichodesmium is a large (about 0.5 by 3 millimeters) phytoplankter that is common in tropical open-ocean waters. measurements of abundance, plus a review of earlier observations, indicate that it, rather than the picophytoplankton, is the most important primary producer (about 165 milligrams of carbon per square meter per day) in the tropical north atlantic ocean. furthermore, nitrogen fixation by trichodesmium introduces the largest fraction of new nitrogen to t ...	1991	17773605
hormogonium differentiation in the cyanobacterium calothrix: a photoregulated developmental process.	hormogonium differentiation is part of the developmental cycle in many heterocystous cyanobacteria. hormogonia are involved in the dispersal and survival of the species in its natural habitat. the formation of these differentiated filaments has been shown to depend on several environmental conditions, including spectral light quality. we report here morphological and ultrastructural changes associated with the formation of hormogonia, as well as optimal light conditions required for their differ ...	1991	12324595
cadmium availability to the cyanobacterium synechocystis aquatilis in solutions containing chloride.	availability of cadmium to synechocystis aquatilis (estimated by 109cd sorption and cadmium toxicity-14c method) in solutions containing cadmium and complexing (kcl) or non-complexing (kno3) salts, in the range of 0-0.5 m was investigated. both cadmium surface adsorption and transport into the cells were lower in solutions containing cadmium chloride complexes (cdcl+, cdcl2, cdcl3-) than in those containing cadmium in the form of cd2+. also, cadmium toxicity in solutions of higher kcl concentrat ...	1992	15091998
na-independent hco(3) transport and accumulation in the cyanobacterium synechococcus utex 625.	the active transport and intracellular accumulation of hco(3) (-) by air-grown cells of the cyanobacterium synechococcus utex 625 (pcc 6301) was strongly promoted by 25 millimolar na(+).na(+)-dependent hco(3) (-) accumulation also resulted in a characteristic enhancement in the rate of photosynthetic o(2) evolution and co(2) fixation. however, when synechococcus was grown in standing culture, high rates of hco(3) (-) transport and photosynthesis were observed in the absence of added na(+). the i ...	1992	16668677
molecular analysis of the psac gene encoding the f(a)/f(b) apoprotein of photosystem i in the filamentous cyanobacterium anabaena variabilis atcc 29413.		1992	16668719
regulation of phycobilisome structure and gene expression by light intensity.	the cyanobacterium agmenellum quadruplicatum pr-6 (synechococcus sp pcc 7002) was grown turbidostatically in white light at three levels of irradiance: 20, 200, and 1260 microeinsteins per square meter per second. phycobilisomes were isolated from each culture and analyzed by absorbance, gel electrophoresis, and electron microscopy. the ratio of phycocyanin to allophycocyanin decreased 1.8-fold from the lowest to highest irradiance. this change was due entirely to an approximately 2.5-fold decre ...	1992	16668720
assembly of two subunits of the cyanobacterial photosystem i on the n-side of thylakoid membranes.	photosystem i contains several peripheral membrane proteins that are located on either positive (luminal) or negative (stromal or cytoplasmic) sides of thylakoid membranes of chloroplasts or cyanobacteria. incorporation of two peripheral subunits into photosystem i of the cyanobacterium synechocystis species pcc 6803 was studied using a reconstitution system in which radiolabeled subunits ii (psad) and iv (psae) were synthesized in vitro and incubated with the isolated thylakoid membranes. after ...	1992	16668856
bicarbonate concentration by synechocystis pcc6803 : modulation of protein phosphorylation and inorganic carbon transport by glucose.	the ability of the cyanobacterium synechocystis pcc6803 to transport inorganic carbon in the form of bicarbonate rapidly decreased following a shift from bicarbonate-limited growth to either excess bicarbonate supply or to photoheterotrophic growth on glucose. nonmetabolizable analogs of glucose did not exert this effect. the rate at which the bicarbonate uptake rate declined was too rapid to be accounted for by dilution of the activity by culture growth and suggested that posttranslational modi ...	1992	16668929
isolation and characterization of a cdna clone encoding the major hsp70 of the pea chloroplastic stroma.	the 70-kd heat shock proteins (hsp70s) are a group of ubiquitous, highly conserved molecular chaperones that have been implicated in a variety of processes, ranging from dna replication to protein folding and transport. to learn more about the evolution and possible functions of higher plant chloroplastic hsp70s, we isolated a cdna clone encoding the major stromal hsp70 of pea chloroplasts, which we term css1 (chloroplastic stress seventy). this cdna clone encodes a 75,490-d protein that is very ...	1992	16653016
association of carbonic anhydrase activity with carboxysomes isolated from the cyanobacterium synechococcus pcc7942.	the development of a simple method for the isolation of purified carboxysomes from the cyanobacterium synechococcus pcc7942 has made it possible to identify a specific and inducible, intracellular carbonic anhydrase (ca) activity that is strongly associated with carboxysomes. this was shown, in part, through enzyme recovery experiments that indicated that a clear majority of a ca activity that is sensitive to the ca inhibitor ethoxyzolamide (i(50) = 4 mum) copurifies with a majority of the cell' ...	1992	16653059
isolation of a putative carboxysomal carbonic anhydrase gene from the cyanobacterium synechococcus pcc7942.	the type ii mutants of the cyanobacterium synechococcus pcc7942 (g.d. price, m.r. badger [1989] plant physiol 91: 514-525) are able to accumulate a large pool of inorganic carbon inside the cell, but are unable to utilize it for co(2) fixation, resulting in a high co(2)-requiring phenotype. we have isolated a 3.5-kb bamhi clone (pt2) that complements the type ii mutants, and complementation analysis with dna subclones indicated that the complementing region was located in the 0.75-kb xhoi-bg/ii ...	1992	16653060
in situ nuclear magnetic resonance of n pulse labels monitors different routes for nitrogen assimilation.	nuclear magnetic resonance offers the possibility of noninvasive in situ observation of (15)n pulse labeling in the presence of light. in vivo, exclusively the delta-nitrogen of gln is labeled in the cyanobacterium microcystis firma when glutamate synthase is inhibited by azaserine. in contrast, the green alga chlorella fusca is additionally capable of incorporating nitrogen into glu, thus providing evidence for an anabolic function of glutamate dehydrogenase in this organism.	1992	16653163
a cyanobacterial gene encoding peptidyl-prolyl cis-trans isomerase.	the rota gene encoding peptidyl-prolyl cis-trans isomerase has been identified, sequenced, and shown to be transcribed in the cyanobacterium synechococcus sp. pcc7942. inactivation of the gene by replacement of a region containing the open reading frame with a gene conferring kanamycin resistance resulted in merodiploids containing both the wild type and the modified genomic region. we were not able to isolate a kanamycin-resistant mutant in which all the genomic wild-type copies were substitute ...	1992	16653227
phenotypic complementation of high co(2)-requiring mutants of the cyanobacterium synechococcus sp. strain pcc 7942 by inosine 5'-monophosphate.	the high co(2)-requiring mutants of synechococcus pcc 7942, d4 and r14, were obtained by deletion or inactivation (respectively) of an open reading frame immediately downstream of rbc (the operon encoding the subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase). these mutants exhibit photosynthetic characteristics similar to those of high co(2)-grown wild type, unlike other cyanobacterial high co(2)-requiring mutants, where the apparent photosynthetic affinity for inorganic carbon is app ...	1992	16653228
dependence on growth phase and temperature of the composition of a nitrogen-fixing cyanobacterium.	the effects of growth phase and temperature on the molecular and elemental composition of anabaena variabilis cells grown under nitrogen-fixing conditions have been studied in batch cultures. irrespective of the growth temperature, this cyanobacterium underwent a gradual increase in its protein and lipid contents in the transition from exponential to deceleration phase that was accompanied by a parallel decrease in carbohydrates and nucleic acids. also in response to this, transition increases i ...	1992	18601167
a structured model for simulation of cultures of the cyanobacterium spirulina platensis in photobioreactors: i. coupling between light transfer and growth kinetics.	the study of the interactions between physical limitation by light and biological limitations in photobioreactors leads to very complex partial differential equations. modeling of light transfer and kinetics and the assessment of radiant energy absorbed in photoreactors require an equation including two parameters for light absorption and scattering in the culture medium. in this article, a simple model based on the simplified, monodimensional equation of schuster for radiative transfer is discu ...	1992	18601185
a structured model for simulation of cultures of the cyanobacterium spirulina platensis in photobioreactors: ii. identification of kinetic parameters under light and mineral limitations.	a structured model for the culture of cyanobacteria in photobioreactors is developed on the basis of schuster's approximations for radiative light transfer. this model is therefore limited to monodimensional geometries and kinetic aspects.light-harvesting pigments play a crucial role in defining the profile of radiative transfer inside the culture medium and in controlling the metabolism, particularly the metabolic deviations induced by mineral limitations. modeling therefore requires the biomas ...	1992	18601186
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
n-terminal amino acid sequence of the chlorophyll-binding protein cp-47 of photosystem 2 in the thermophilic cyanobacterium synechococcus elongatus.		1992	1368306
cloning and nucleotide sequence of a frxc-orf469 gene cluster of synechocystis pcc6803: conservation with liverwort chloroplast frxc-orf465 and nif operon.	a gene, frxc, which is unique to the chloroplast genome of the liverwort marchantia polymorpha, has sequence similarity to nifh, the product of which is an iron protein of a nitrogenase. although frxc is expressed to produce a protein in liverwort chloroplasts, its function is not known. using a probe of liverwort chloroplast dna, a 10.1-kb region containing a gene cluster consisting of open reading frames (orf278-frxc-orf469-orf248) was isolated from the cyanobacterium synechocystis pcc6803. in ...	1992	1368342
generation of lysoglyceroglycolipids in the cyanobacterium, phormidium tenue.	two kinds of lysoglycolipids, monogalactosyl 1-monoacylglycerol and digalactosyl 1-monoacylglycerol were generated in the cyanobacterium, phormidium tenue, when it was stored at -20 degrees for more than 1 month. by comparison of the compositions of fatty acid residues between monogalactosyl 1-monoacylglycerol and monogalactosyl diacylglycerol, digalactosyl 1-monoacylglycerol and digalactosyl diacylglycerol, respectively, the 1-monoacylgalactolipids were presumed to be formed by regioselective d ...	1992	1368418
conjugative gene transfer in marine cyanobacteria: synechococcus sp., synechocystis sp. and pseudanabaena sp.	versatility of gene transfer by transconjugation in marine cyanobacteria was demonstrated. in this study, seven different marine cyanobacteria were used as recipient cells. first, transconjugation was carried out using the mobilizable transposon (tn5) carrying plasmid psup1021. transconjugates were observed in all marine cyanobacteria tested. second, the broad-host-range vector pkt0230 (incq) was tested for transconjugation. pkt230 has been successfully transferred in a marine cyanobacterium syn ...	1992	1368911
cytoskeletal changes in hepatocytes induced by microcystis toxins and their relation to hyperphosphorylation of cell proteins.	the heptapeptide toxins produced by the blue-green alga (cyanobacterium) microcystis aeruginosa are selectively hepatotoxic in mammals. the characteristic post-mortem pathology of the liver is extensive lobular disruption due to sinusoidal breakdown, leakage of blood into the tissue and hepatocyte disintegration. isolated hepatocytes incubated with toxin show severe structural deformity and surface blebbing. this paper demonstrates the effects of microcystis toxins on the contraction and aggrega ...	1992	1370395
sequence of the ribonuclease p rna gene from the cyanobacterium anacystis nidulans.		1992	1371871
light-regulated expression of the psbd gene family in synechococcus sp. strain pcc 7942: evidence for the role of duplicated psbd genes in cyanobacteria.	the genome of the cyanobacterium synechococcus sp. strain pcc 7942 contains two psbd genes encoding the d2 protein of the photosystem ii reaction center: psbdi, which is cotranscribed as a discistronic message with psbc (the gene encoding cp43, a chlorophyll-a binding protein), and psbdii, which is monocistronic. northern blot analysis of psbd transcripts showed that the two genes responded differently when wild-type cells were shifted from moderate to high light intensity. whereas psbdii transc ...	1992	1372952
protective effects of ca2+, mg2+, cu2+, and ni2+ on mercury and methylmercury toxicity to a cyanobacterium.	toxicological investigations of the impact of inorganic mercury (hg2+) and methylmercury (ch3hg+) in terms of growth, nh4+ uptake, in vivo glutamine synthetase (transferase) activity, and regulation of toxicity by ca2+, mg2+, cu2+ and ni2+ in the diazotrophic cyanobacterium nostoc calcicola bréb. have been completed. photoautotrophic growth of the cyanobacterium was extremely sensitive to both mercury compounds, ch3hg+ being 2.5 times more toxic than hg2+. although nh4+ uptake was 6 times more s ...	1992	1375141
a nitrate reductase gene of the cyanobacterium synechococcus pcc6301 inferred by heterologous hybridization, cloning and targeted mutagenesis.	dna probes from the narg gene of escherichia coli, which encodes the large polypeptide of respiratory nitrate reductase, show cross-hybridization at low stringency to a single region of the genome of the cyanobacterium synechococcus pcc6301. this segment of cyanobacterial dna was cloned as the insert of plasmid pdn1 and characterized. rna complementary to pdn1 was shown to be substantially more abundant in nitrate grown cells of synechococcus pcc6301 than in ammonium grown cells, thus parallelli ...	1992	1378036
identification of multiple rna polymerase sigma factor homologs in the cyanobacterium anabaena sp. strain pcc 7120: cloning, expression, and inactivation of the sigb and sigc genes.	the siga gene of anabaena sp. strain pcc 7120, encoding the principal rna polymerase sigma factor, and the complement of the rpod oligonucleotide (k. tanaka, t. shiina, and h. takahashi, science 242:1040-1042, 1988) were used as probes to isolate two genes, sigb and sigc, which encode two putative sigma factors exhibiting high degrees of similarity to siga, to hrda, -b, -c, and -d of streptomyces coelicolor, and to katf of escherichia coli. sigb and sigc code for polypeptides of 332 and 416 amin ...	1992	1385387
abscisic acid and its synthetic analog in relation to growth and nitrogenase activity of azotobacter chroococcum and nostoc muscorum.	the plant hormone abscisic acid as well as its synthetic analog lab 173711 significantly increased the nitrogenase activity of the bacterium azotobacter chroococcum and the cyanobacterium nostoc muscorum. the effect depended on the concentration of the substances (0.001-10 mg/l) and the age of the cultures. the biomass of the organisms was not significantly influenced.	1992	1387101
three new microcystins, cyclic heptapeptide hepatotoxins, from nostoc sp. strain 152.	three new cyclic heptapeptide hepatotoxins, [d-ser1,admadda5]microcystin-lr (1), [d-asp3,-admadda5]microcystin-lhar (2), and [admadda5,mser7]microcystin-lr (3), were isolated from the cyanobacterium (blue-green alga) nostoc sp. strain 152, together with four known microcystins, [admadda5]microcystin-lr (4), [admadda5]microcystin-lhar (5), [d-asp3,-admadda5]microcystin-lr (6), and [dmadda5]microcystin-lr (7). the structures of new microcystins were assigned on the basis of high-resolution fast at ...	1992	1391612
in vitro activation of dinitrogenase reductase from the cyanobacterium anabaena variabilis (atcc 29413).	nitrogenase of the heterocystous cyanobacterium anabaena variabilis was inactivated in vivo (s. reich, h. almon, and p. böger, fems microbiol. lett. 34:53-56, 1986). partially purified and modified (inactivated) dinitrogenase reductase (fe-protein) of such cells was reactivated by isolated membrane fractions of a. variabilis or of rhodospirillum rubrum, and acetylene reduction was measured. reactivation requires atp, mg2+, and mn2+. the activating principle is localized in the heterocyst and was ...	1992	1400166
isolation of arginine auxotrophs, cloning by mutant complementation, and sequence analysis of the argc gene from the cyanobacterium anabaena species pcc 7120.	arginine auxotrophs of the dinitrogen-fixing cyanobacterium anabaena species strain pcc 7120 were isolated after ultraviolet light mutagenesis and penicillin enrichment. two of these auxotrophs were complemented by a cosmid gene library of the wild-type strain established in escherichia coli that was transferred en masse to the mutants by conjugation. the gene complementing one of those mutants was found to complement an e. coli argc mutant. sequencing analysis of the gene showed that it encodes ...	1992	1406250
complementation of a red-light-indifferent cyanobacterial mutant.	many cyanobacteria alter their phycobilisome composition in response to changes in light wavelength in a process termed complementary chromatic adaptation. mutant strains fdr1 and fdr2 of the filamentous cyanobacterium fremyella diplosiphon are characterized by aberrant chromatic adaptation. instead of adjusting to different wavelengths of light, fdr1 and fdr2 behave as if they are always in green light; they do not respond to red light. we have previously reported complementation of fdr1 by con ...	1992	1409650
unsaturation of fatty acids in membrane lipids enhances tolerance of the cyanobacterium synechocystis pcc6803 to low-temperature photoinhibition.	effect of the unsaturation of fatty acids in the glycerolipids of thylakoid membranes on low-temperature photoinhibition of photosynthesis was studied by mutation and transformation of the cyanobacterium synechocystis pcc6803. when grown at 34 degrees c, the wild type contained mono-, di-, and triunsaturated lipids; a mutant, designated fad6, contained mono- and diunsaturated lipids; and a transformant of fad6, with a disrupted gene for desaturation and designated fad6/desa::kmr, contained only ...	1992	1409727
dna sequence and analysis of a cryptic 4.2-kb plasmid from the filamentous cyanobacterium, plectonema sp. strain pcc 6402.	the 4194-bp plasmid, prf1, from plectonema sp. strain pcc 6402 was completely sequenced and analyzed. seven potential open reading frames were identified. the predicted amino acid sequence of open reading frame c (orf c) had identities of 34, 29, and 25% with rep b from the staphylococcus aureus plasmid, pub110; rep from the bacillus amyloliquefaciens plasmid, pftb14; and protein a from the s. aureus plasmid, pc194, respectively. a 75-amino-acid region conserved in these proteins (rep b, rep, an ...	1992	1409974
ferredoxin-nadp+ oxidoreductase of c. paradoxa nucleus encoded, but cyanobacterial gene transfer from symbiont to host, an evolutionary mechanism originating new species.	the nucleus encoded cyanoplast ("cyanellar") ferredoxin-nadp + oxidoreductase (fnr) of cyanophora paradoxa, characterized by an n-terminal amino acid sequence, is compared with homologous sequences of other photoautotrophic organisms. the high degree of similarity to the cyanobacterial sequences indicates a cyanobacterial origin. this could be a first direct demonstration of an intertaxonic combination: a gene transfer from an original endocytobiont (cyanobacterium) to the nucleus of its host, o ...	1992	1418237
role of the carboxy terminus of polypeptide d1 in the assembly of a functional water-oxidizing manganese cluster in photosystem ii of the cyanobacterium synechocystis sp. pcc 6803: assembly requires a free carboxyl group at c-terminal position 344.	the d1 polypeptide of the photosystem ii (psii) reaction center is synthesized as a precursor polypeptide which is posttranslationally processed at the carboxy terminus. it has been shown in spinach that such processing removes nine amino acids, leaving ala344 as the c-terminal residue [takahashi, m., shiraishi, t., & asada, k. (1988) febs lett. 240, 6-8; takahashi, y., nakane, h., kojima, h., & satoh, k. (1990) plant cell physiol. 31, 273-280]. we show here that processing on the carboxy side o ...	1992	1420199
cloning and characterization of the secy gene from the cyanobacterium synechococcus pcc7942.	the secy gene product is an essential component of the escherichia coli cytoplasmic membrane, which mediates the protein translocation across the membrane. we found a gene homologous to secy in the genome of the cyanobacterium synechococcus pcc7942. the deduced amino acid sequence, 439 amino acids long, shows 43% homology with that of the e. coli secy. the hydrophobic profile suggests that the synechococcus secy protein is an integral membrane protein containing ten membrane-spanning segments, w ...	1992	1420358
cloning and sequencing of the petbd operon from the cyanobacterium synechococcus sp. pcc 7002.	the genes encoding the photosynthetic cytochrome b6 (petb) and subunit 4 (petd) have been cloned and sequenced from the unicellular, photoheterotrophic, transformable cyanobacterium synechococcus sp. pcc 7002, formerly designated agmenellum quadruplicatum. the gene arrangement was found to be similar to that reported in the cyanobacterium nostoc pcc 7906. the dna and derived protein sequences were compared to chloroplast and the other cyanobacterial sequences. by pulsed-field electrophoresis, th ...	1992	1421151
nucleotide sequence of a metallothionein gene of the thermophilic cyanobacterium synechococcus vulcanus.		1992	1421159
thermally-induced delayed fluorescence of photosystem i and ii chlorophyll in thermophilic cyanobacterium synechococcus elongatus.	stationary delayed fluorescence (df) of chlorophyll in isolated membrane preparations from thermophilic cyanobacterium synechococcus elongatus was investigated as a function of temperature. two peaks at different temperatures were observed. the low-temperature peak (54-60 degrees c) coincided with the main maximum of the thermally-induced delayed fluorescence of chlorophyll in intact cells and psii-particles with active oxygen-evolving system. the high-temperature peak (78 degrees c) coincided w ...	1992	1426973
excitation energy transfer from phycocyanin to chlorophyll in an apca-defective mutant of synechocystis sp. pcc 6803.	a greenish mutant of the normally blue-green cyanobacterium synechocystis sp. pcc 6803, designated uv6p, has been isolated and characterized. uv6p possesses functional photosystems i and ii (psi and psii) but lacks normal light harvesting phycobilisomes because allophycocyanin is absent and core-specific linker proteins are almost entirely absent. the mutation responsible for the uv6p phenotype has been identified; it is a base substitution which results in the creation of a termination codon wi ...	1992	1429645
structure determination and toxicity of a new microcystin from microcystis aeruginosa strain 205.	a new hepatotoxic microcystin was isolated from the cyanobacterium microcystis aeruginosa strain 205. its structure was found to be [dha7]microcystin-rr as determined by amino acid analysis, mass spectrometry and 1h nmr spectroscopy. ld50 value (i.p. mouse) of this toxin was 180 micrograms/kg. the 48 hr lethal concentration (48-hr-lc50) of the toxin for larvae of the yellow fever mosquito, aedes aegypti, was 14.9 micrograms/ml.	1992	1440646
identification of arginyl residues involved in the binding of ferredoxin-nadp+ reductase from anabaena sp. pcc 7119 to its substrates.	ferredoxin-nadp+ reductase from the cyanobacterium anabaena sp. pcc 7119 was chemically modified by the alpha-dicarbonyl reagent phenylglyoxal. the studies of the inactivation by this compound, which is specific for arginyl residues, of both the diaphorase and nadph-cytochrome c reductase activities, characteristic of the enzyme, are indicative of the involvement of at least one group of this kind in the binding site of nadp+ and a second one implicated in the interaction with ferredoxin. after ...	1992	1444467
effects of mutations at residue 309 of the large subunit of ribulosebisphosphate carboxylase from synechococcus pcc 6301.	previous studies [g. s. hudson et al. (1989) j. biol. chem. 265, 808-814] showed that the faster turnover rates and lower affinities for co2 of ribulosebisphosphate carboxylase/oxygenases from c4 plants, compared to c3 and c3/c4 plants, were specified by the chloroplast-encoded large subunits. in pairs of closely related c3 and c4 species from three genera, these kinetic changes were accompanied by only three to six amino acid residue substitutions, depending on the genus. none of these substitu ...	1992	1444469
purification and properties of urease from the cyanobacterium anabaena cylindrica.	a purification procedure has been developed by which urease activity in extracts from the cyanobacterium anabaena cylindrica was enriched 500-fold. the procedure involves mgso4 precipitation at 55 degrees c and chromatography on hydroxylapatite and diethylaminoethyl sephadex. its molecular weight was measured by sedimentation equilibrium in an airfuge to be 197,000 +/- 2000 with an estimated subunit molecular weight of 32,000 as determined by polyacrylamide gel electrophoresis. the ph- and tempe ...	1992	1445371
energy transfer (deazaflavin-->fadh2) and electron transfer (fadh2-->t <> t) kinetics in anacystis nidulans photolyase.	dna photolyases catalyze the photocycloreversion of cyclobutane pyrimidine dimers. the enzyme from the cyanobacterium anacystis nidulans contains two chromophores, 1,5-dihydroflavin adenine dinucleotide (fadh2) and 7,8-didemethyl-8-hydroxy-5-deazariboflavin (8-hdf). the photophysical/photochemical reactions leading to dna repair were investigated by using time-resolved and steady-state fluorescence spectroscopy. it was found that the excited singlet state of 8-hdf transfers energy to fadh2 at a ...	1992	1445863
site-directed mutagenesis of the cpa-1 protein of photosystem ii: alteration of the basic residue pair 384,385r to 384,385g leads to a defect associated with the oxygen-evolving complex.	the psbb gene encodes the intrinsic chlorophyll-a binding protein cpa-1 (cp-47), a component of photosystem ii in higher plants, algae, and cyanobacteria. oligonucleotide-directed mutagenesis was used to introduce mutations into a segment of the psbb gene encoding the large extrinsic loop region of cpa-1 in the cyanobacterium synechocystis sp. pcc 6803. altered psbb genes were introduced into a mutant recipient strain (del-1) of synechocystis in which the genomic psbb gene had been partially del ...	1992	1445882
structures of three new homotyrosine-containing microcystins and a new homophenylalanine variant from anabaena sp. strain 66.	a hepatotoxic strain of cyanobacterium anabaena sp. 66 was isolated from a hepatotoxic water bloom sample in lake kiikkara, finland. four cyclic heptapeptide hepatotoxins were isolated and purified by hplc from cultured cells of this organism. the structures of three new homotyrosine (hty) containing toxins, [dha7]microcystin-htyr (dha = dehydroalanine) (1), [d-asp3,dha7]microcystin-htyr (2), and [l-ser7]microcystin-htyr (3), were assigned, based upon amino acid analyses using both a waters pico ...	1992	1446006
beyond the barcoo--probable human tropical cyanobacterial poisoning in outback australia.	to determine the cause of a disease known variously as "barcoo fever, barcoo spews, barcoo sickness", or simply "the barcoo", once prevalent in outback northern and central australia.	1992	1454012
effects of chemical modification of anabaena flavodoxin and ferredoxin-nadp+ reductase on the kinetics of interprotein electron transfer reactions.	the influence of chemical modification of arginine residues (using phenylglyoxal) in ferredoxin-nadp+ reductase (fnr), and of carboxyl groups (using glycine ethyl ester) in flavodoxin (fld), on the kinetics of electron transfer between fnr and fld, and between ferredoxin (fd) and fnr, was examined using laser flash photolysis methods. all proteins were obtained from the cyanobacterium anabaena pcc7119. reduction by laser-generated 5-deazariboflavin semiquinone of the fad moiety of phenylglyoxal- ...	1992	1459139
structure and expression of a cyanobacterial ilvc gene encoding acetohydroxyacid isomeroreductase.	acetohydroxyacid isomeroreductase (ahair) is the shared second enzyme in the biosynthetic pathways leading to isoleucine and valine. ahair is encoded by the ilvc gene in bacteria. a 1,544-bp fragment of genomic dna containing the ilvc gene was cloned from the cyanobacterium synechocystis sp. strain pcc 6803, and the complete nucleotide sequence was determined. the identity of the gene was established by comparison of the nucleotide and derived peptide sequences with those of other ilvc genes. th ...	1992	1459938
presence of an n-terminal presequence in the psai protein of the photosystem i complex in the filamentous cyanobacterium anabaena variabilis atcc 29413.	the psai gene encoding the 5.2 kda protein component (psai) of the photosystem i complex was cloned from the cyanobacterium anabaena 29413. the gene is present in single copy in this cyanobacterial genome. the nucleotide sequence of a 500 bp region of the cloned dna revealed the presence of an open reading frame encoding a 46 amino acid long polypeptide. the n-terminal 11 residues are absent in the mature polypeptide and thus represents the first identified cleavable presequence on the psai prot ...	1992	1463834
identification of a second psac gene in the cyanobacterium synechocystis sp. pcc6803.	the psac gene encodes the 9 kda protein subunit of photosystem i that carries the iron-sulfur centers fa and fb. the paper describes the sequence and transcription analysis of a second psac gene (psac2) from synechocystis sp. pcc6803. thepsac2 gene is transcribed into an abundant monocistronic mrna. the deduced amino acid sequence of psi-c2 is very similar to the protein sequences from two other cyanobacteria (synechococcus sp. pcc7002 and nostoc sp. pcc8009). in contrast, the recently isolated ...	1992	1463835
cloning and transcription analysis of the ndh(a-i-g-e) gene cluster and the ndhd gene of the cyanobacterium synechocystis sp. pcc6803.	the plastid dna of higher plants contains eleven reading frames that are homologous to subunits of the mitochondrial nadh-ubiquinone oxidoreductase (complex i). the genes are expressed, but a plastid nad(p)h dehydrogenase has not yet been isolated and the function of the enzyme in plastid metabolism is unknown. cyanobacteria also contain a nadh dehydrogenase that is homologous to the mitochondrial complex i. the enzyme is sensitive to rotenone and is located on the cytoplasmic and the thylakoid ...	1992	1463844
primary structure of the synechococcus pcc 7942 paps reductase gene.	the structural gene encoding a thioredoxin-dependent 5'-phosphoadenylyl sulphate (paps) reductase (ec 1.8.4.-) from cyanobacterium synechococcus pcc 7942 ('anacystis nidulans') was detected by heterologous hybridization with the cysh gene from escherichia coli k12. the cyanobacterial gene (further called par gene) comprised 696 nt which are 57.8% homologous to the enterobacterial gene. the putative open reading frame encoded a polypeptide consisting of 232 amino acid residues (deduced molecular ...	1992	1463852
restoration of the wild-type locus in an rubp carboxylase/oxygenase mutant of synechocystis pcc 6803 via targeted gene recombination.	the interaction between homologous dna sequences, distant from each other in the chromosome, was examined in the cyanobacterium synechocystis pcc 6803. most of the rbcl gene encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rubisco) was duplicated in the genome by a targeted insertion of a 3'-truncated gene copy into the psb a-i locus. both rbcl genes, in the psb a-i region and at the rbc locus, were non-functional; the former due to the 3' truncation, and the latter due ...	1992	1465099
purification, characterization and function of dihydrolipoamide dehydrogenase from the cyanobacterium anabaena sp. strain p.c.c. 7119.	a dihydrolipoamide dehydrogenase (dihydrolipoamide: nad+ oxidoreductase, ec 1.8.1.4) (dld) has been found in the soluble fraction of cells of both unicellular (synechococcus sp. strain p.c.c. 6301) and filamentous (calothrix sp. strain p.c.c. 7601 and anabaena sp. strain p.c.c. 7119) cyanobacteria. dld from anabaena sp. was purified 3000-fold to electrophoretic homogeneity. the purified enzyme exhibited a specific activity of 190 units/mg and was characterized as a dimeric fad-containing protein ...	1992	1471997
two new l-serine variants of microcystins-lr and -rr from anabaena sp. strains 202 a1 and 202 a2.	two new microcystins, [l-ser7]microcystin-lr (1) and [l-ser7]microcystin-rr (2), were isolated from a filamentous fresh water cyanobacterium (blue-green alga), anabaena sp. strain 202 a1, along with the two major toxins, [dha7]microcystin-lr (3) and [dha7]microcystin-rr (4) and their minor components the d-asp variants [d-asp3,dha7]microcystin-lr (5) and [d-asp3,dha7]microcystin-rr (6). anabaena sp. strain 202 a1 also produced another new toxin, whose structure is tentatively proposed as [d-asp3 ...	1992	1485340
the cyanobacterium oscillatoria erythraea--a potential source of toxin in the ciguatera food-chain.	a compound lethal to mice (i.p.) was extracted from samples of oscillatoria erythraea, four species of mollusc and one species of molluscivorous teleost collected from the south-east coast of queensland, australia, during and shortly after o. erythraea blooms. the compound was chemically indistinguishable from ciguatoxin (ctx) on the basis of solvent extraction and partitioning and silicic acid chromatography. residues derived from toxic samples elicited signs of intoxication, death and histopat ...	1992	1493884
phycocyanin alpha-subunit phycocyanobilin lyase.	phycobiliproteins, unlike other light-harvesting proteins involved in photosynthesis, bear covalently attached chromophores. the bilin chromophores are attached through thioether bonds to cysteine residues. the cyanobacterium synechococcus sp. pcc 7002 has eight distinct bilin attachment sites on seven polypeptides, all of which carry the same chromophore, phycocyanobilin. when two genes in the phycocyanin operon of this organism, cpce and cpcf, are inactivated by insertion, together or separate ...	1992	1495995
mutations in the d1 subunit of photosystem ii distinguish between quinone and herbicide binding sites.	the structure-activity relationships of the plastoquinone qb binding domain in the d1 subunit of photosystem ii (psii) were investigated by characterization of mutations introduced in the d1 protein. eight novel point mutations in the gene psba, which encodes d1, were generated in the cyanobacterium synechocystis pcc6803 by site-specific mutagenesis in vitro. the effects of the resulting modifications in d1 on electron transfer in psii and on herbicide binding were analyzed. the results extend t ...	1992	1498597
evidence for an ultraviolet sunscreen role of the extracellular pigment scytonemin in the terrestrial cyanobacterium chlorogloeopsis sp.	the proposed photoprotective role of the uv-a absorbing, extracellular pigment scytonemin was studied in the terrestrial cyanobacterium chlorogloeopsis sp. strain o-89-cgs(1). uv-a (315-400 nm) caused growth delay, cell growth restarting only when scytonemin had accumulated in the extracellular envelopes. cultures with scytonemin were more resistant to photoinhibition of photosynthesis than cultures without scytonemin, the differential resistance being much greater to uv-a-caused photoinhibition ...	1992	1508978
oxygen yield and thermoluminescence characteristics of a cyanobacterium lacking the manganese-stabilizing protein of photosystem ii.	previous experiments have shown that a synechocystis sp. pcc 6803 mutant (delta psbo) lacking the extrinsic manganese-stabilizing protein (msp) exhibits impaired, but significant levels of h2o-splitting activity [burnap, r., & sherman, l.a. (1991) biochemistry 30, 440-446]. [14c]dcmu-binding experiments now show that the number and affinity of dcmu-binding sites (normalized to chlorophyll) are equivalent in delta psbo and the wild type, suggesting equal concentrations of assembled reaction cente ...	1992	1510930
the complete nucleotide sequence of the gene (rpod1) encoding the principal sigma factor of the rna polymerase from the cyanobacterium synechococcus sp. strain pcc7942.	the complete nucleotide sequence of rpod1 gene from synechococcus pcc7942 has been determined. the nucleotide data have indicated the presence of an open reading frame of 1155 base pairs encoding a polypeptide which shares the framework structure for principal sigma factors of eubacterial strains.	1992	1511015
molecular characterization of the genes encoding acetohydroxy acid synthase in the cyanobacterium spirulina platensis.	the enzyme acetohydroxy acid synthase (ahs), which catalyses the first common step in the biosynthesis of isoleucine, leucine and valine, has been demonstrated to be present in spirulina platensis in two isoenzymic forms. the complete nucleotide sequences of the genes ilvx and ilvw encoding these two enzymes have been determined. sequence analysis revealed the presence of two open reading frames, of 1836 and 1737 nucleotides for ilvx and ilvw, respectively. the predicted amino acid sequences of ...	1992	1512571
cytotoxicity of cyanobacterium microcystis aeruginosa.	cytotoxic effects of crude extracts and fractions of the purification steps towards microcystin-lr (mcyst-lr) were investigated in vitro. cytotoxicity was evaluated by measure of lactate dehydrogenase liberation of chang liver cells and by hemolysis. crude extracts of strain pcc 7806 damaged the cells within a few minutes. in contrast, mcyst-lr did not show any detectable cytotoxic effects. the cytotoxic activity could be related to a heat-labile substance with a molecular weight of about 30,000 ...	1992	1519410
characterization of a light-regulated gene encoding a new phycoerythrin-associated linker protein from the cyanobacterium fremyella diplosiphon.	cyanobacteria utilize multimeric protein complexes, the phycobilisomes, as their major light-harvesting antennae. associated with the chromophorylated phycobiliproteins in these complexes are nonpigmented proteins, designated linker proteins. these linker proteins are believed to mediate assembly of the phycobilisome and energy transfer to the photosynthetic reaction center. we cloned and sequenced a gene, cpee, encoding a previously uncharacterized linker protein which is expressed in green lig ...	1992	1522075
[sequence and primary structure analysis of specific dna fragment related to pollen fertility in radish chloroplast genome].	nucleotide sequence of a radish chloroplast bafhi-ecori fragment (zl1) derived from b21, which is related to cytoplasmic male sterility and also found in radish 401b retaining line, has been determined. the results show that this fragment is 474bp in length, and is rich in at base components. the nucleotide sequence of zl1 has 96.6% homology as compared with the corresponding sequence of tobacco which is located at the positions from 142330 to 142803 in ira and from 100199 to 99726 in irb in the ...	1992	1524844
the homologies of gas vesicle proteins.	in addition to gvpa, the main structural protein, an sds-soluble protein has been found in gas vesicles isolated from six different genera of cyanobacteria. n-terminal sequence analysis of the first 30 to 60 residues of the gel-purified proteins showed that they were homologous to gvpc, a protein that strengthens the gas vesicle in anabaena flos-aquae. the proteins from some of the organisms showed rather low homology, however, and this may explain why the genes that encode them have not been fo ...	1992	1527496
an iron stress operon involved in photosynthetic electron transport in the marine cyanobacterium synechococcus sp. pcc 7002.	the iron-stress-induced genes isia and isib have been cloned and sequenced from the marine unicellular cyanobacterium synechococcus sp. pcc 7002. these genes code for a photosystem ii chlorophyll-binding protein and flavodoxin respectively. the genes form a dicistronic operon that is transcriptionally activated under iron-stress conditions to produce an abundant monocistronic message containing isia and a much less abundant dicistronic message that also contains isib. the arrangement of these ge ...	1992	1527503
characterization of damage to photosystems i and ii in a cyanobacterium lacking detectable iron superoxide dismutase activity.	the enzyme superoxide dismutase is ubiquitous in aerobic organisms where it plays a major role in alleviating oxygen-radical toxicity. an insertion mutation introduced into the iron superoxide dismutase locus (designated sodb) of the cyanobacterium synechococcus sp. pcc 7942 created a mutant strain devoid of detectable iron superoxide dismutase activity. both wild-type and mutant strains exhibited similar photosynthetic activity and viability when grown with 17 mumol.m-2.s-1 illumination in liqu ...	1992	1528884
nickel effects on phosphate uptake, alkaline phosphatase, and atpase of a cyanobacterium.		1992	1533803
purification, characterization and function of bacterioferritin from the cyanobacterium synechocystis p.c.c. 6803.	storage and buffering of iron is achieved by a class of proteins, the ferritins, widely distributed throughout the living kingdoms. all ferritins have in common their three-dimensional structure and their ability to store large amounts of iron in their central cavity. however, eukaryotic ferritins from plants and animals and bacterioferritins have no sequence similarity, and besides non-haem iron bacterioferritins contain haem residues whereas eukaryotic ferritins do not. in this paper we report ...	1992	1536655
heat shock hsp70 protein is chloroplast-encoded in the chromophytic alga pavlova lutherii.	heat shock proteins are ubiquitous and highly conserved. recently they have become implicated in the import of proteins into organelles. all the heat shock genes characterized to date, however, are known or assumed to be encoded in the nuclear genome even if the corresponding protein can be localised in the mitochondrion or chloroplast. in contrast, we identify here an hsp70 gene in the unicellular chromophytic alga pavlova lutherii which is located on the chloroplast genome. localisation of thi ...	1992	1536924
molecular cloning and expression in escherichia coli of a cyanobacterial gene coding for phytoene synthase, a carotenoid biosynthesis enzyme.	the first committed step in the biosynthetic pathway of carotenoids in plants and algae is the conversion of geranylgeranyl pyrophosphate (ggpp) to prephytoene pyrophosphate (pppp), which is converted to phytoene. we have cloned the gene pys that encodes the enzyme phytoene synthase in the cyanobacterium synechococcus pcc7942. the co-expression of pys in cells of escherichia coli together with the gene crte from erwinia uredovora, which encodes geranylgeranyl pyrophosphate synthase, resulted in ...	1992	1537409