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sensitivity of macrophyte-dominated freshwater microcosms to chronic levels of the herbicide linuron. i. primary producers.effects of chronic concentrations of linuron (0, 0.5, 5, 15, 50, and 150 micrograms/l) were studied in indoor, macrophyte dominated, freshwater microcosms. the concentrations were kept at a constant level for 4 weeks. this paper is the first in a series of two and summarizes the course of the linuron concentrations in time and its effects on macrophytes, periphyton, and phytoplankton. these endpoints were studied from 3 weeks before the start of the treatment until 11 weeks after the start. the ...19979352210
oscillin, an extracellular, ca2+-binding glycoprotein essential for the gliding motility of cyanobacteria.electron microscopic studies have demonstrated that various gliding filamentous cyanobacteria have trichome surfaces with a common structural organization. they contain an s-layer attached to the outer membrane and an array of parallel fibrils on top of the s-layer. in all species studied, the helical arrangement of these fibrils corresponds to the sense of rotation of the organism during the gliding movement. we have investigated the surface fibrils of phormidium uncinatum using electron micros ...19979427400
new acylated sulfoglycolipids and digalactolipids and related known glycolipids from cyanobacteria with a potential to inhibit the reverse transcriptase of hiv-1.five novel diacylated sulfoglycolipids (1-5) were isolated from the cyanobacterium scytonema sp. (tau strain sl-30-1-4) and four novel acylated diglycolipids (6-9) were isolated from the cyanobacterium oscillatoria raoi (tau strain il-76-1-2). these two groups of glycolipids and related known glycolipids isolated from these two and three other strains of cyanobacteria, phormidium tenue (tau strain il-144-1), o. trichoides (tau strain il-104-3-2), and o. limnetica (tau strain ng-4-1-2), were foun ...19979428159
heavy metal binding and removal by phormidium. 19989595189
analysis of the structure and substrate binding of phormidium lapideum alanine dehydrogenase.the structure of the hexameric l-alanine dehydrogenase from phormidium lapideum reveals that the subunit is constructed from two domains, each having the common dinucleotide binding fold. despite there being no sequence similarity, the fold of alanine dehydrogenase is closely related to that of the family of d-2-hydroxyacid dehydrogenases, with a similar location of the active site, suggesting that these enzymes are related by divergent evolution. l-alanine dehydrogenase and the 2-hydroxyacid de ...19989665169
structural and biochemical analysis of the sheath of phormidium uncinatum.the sheath of the filamentous, gliding cyanobacterium phormidium uncinatum was studied by using light and electron microscopy. in thin sections and freeze fractures the sheath was found to be composed of helically arranged carbohydrate fibrils, 4 to 7 nm in diameter, which showed a substantial degree of crystallinity. as in all other examined motile cyanobacteria, the arrangement of the sheath fibrils correlates with the motion of the filaments during gliding motility; i.e., the fibrils formed a ...19989683490
crystallization of the alanine dehydrogenase from phormidium lapideum.amino-acid dehydrogenases catalyse the interconversion of their respective amino acids to the corresponding keto acid, with concomitant reduction of nad or nadp. the enzymes phenylalanine, glutamate, leucine and valine dehydrogenase all share a similar three-dimensional subunit structure and a high degree of sequence similarity, indicating that they belong to an enzyme superfamily related by divergent evolution. in contrast, alanine dehydrogenase shows no sequence similarity with any of these en ...19989761911
[the cultivation of fossaria cubensis (pfeiffer) (pulmonata: lymnaeidae), the intermediate host of fasciola hepatica (linnaeus) in cuba].a method for the culture of fossaria cubensis (pfeiffer), the major intermediate host of fascioliasis in cuba, was assessed. for this purpose, an algae-bearing plate was designed based on a culture of cyanophyceae algae from lyngbya, leotolyngbya, phormidium, and schimidleinema on petri plates 12 cm in diameter with mud substrate and high levels of nitrate and calcium carbonate. fifteen days after incubation with continuous light, these plates were used as aquaria for mollusc breeding. under suc ...19959805072
hierridin b and 2,4-dimethoxy-6-heptadecyl-phenol, secondary metabolites from the cyanobacterium phormidium ectocarpi with antiplasmodial activity.bioassay guided fractionation of the lipophilic extract of the marine cyanobacterium phormidium ectocarpi yielded a new natural product hierridin b and the previously described compound 2,4-dimethoxy-6-heptadecyl-phenol. both structures were secured by extensive spectroscopic analysis (1d and 2d nmr, ms, gc-ms, ir). the isolate (mixture) showed antiplasmodial activity towards plasmodium falciparum.19989887530
the structure of plastocyanin from the cyanobacterium phormidium laminosum.the crystal structure of the 'blue' copper protein plastocyanin from the cyanobacterium phormidium laminosum has been solved and refined using 2.8 a x--ray data. p. laminosum plastocyanin crystallizes in space group p43212 with unit-cell dimensions a = 86.57, c = 91.47 a and with three protein molecules per asymmetric unit. the final residual r is 19.9%. the structure was solved using molecular replacement with a search model based on the crystal structure of a close homologue, anabaena variabil ...199910089349
purification, properties and enhanced expression under nitrogen starvation of the nadp+-isocitrate dehydrogenase from the cyanobacterium phormidium laminosum.nitrogen starvation enhances up to 8-fold the cellular level of the nadp+-dependent isocitrate dehydrogenase activity (isocitrate:nadp+ oxidoreductase (decarboxylating), idh, ec 1.1.1.42) in the thermophilic filamentous non-n2-fixing cyanobacterium phormidium laminosum. the enzyme was purified 650-fold to electrophoretic homogeneity from nitrogen-starved cells with an activity yield of 25% and a specific activity of 500 u (mg protein)-1. the native enzyme showed a pi of 5.9 and it was a dimer of ...199910209282
expression of plastocyanin and cytochrome f of the cyanobacterium phormidium laminosum in escherichia coli and paracoccus denitrificans and the role of leader peptides.the gene for plastocyanin from the cyanobacterium phormidium laminosum was successfully expressed in escherichia coli. expression of the gene for cytochrome f resulted in the production of holocytochrome f in the periplasmic space of e. coli, but the yield was low. expression in paracoccus denitrificans yielded no holoprotein. when the region encoding the cytochrome f leader sequence was replaced with more typical bacterial leader sequences (those from the p. laminosum plastocyanin gene and the ...199910395900
structure of the soluble domain of cytochrome f from the cyanobacterium phormidium laminosum.cytochrome f from the photosynthetic cytochrome b(6)f complex is unique among c-type cytochromes in its fold and heme ligation. the 1. 9-a crystal structure of the functional, extrinsic portion of cytochrome f from the thermophilic cyanobacterium phormidium laminosum demonstrates that an unusual buried chain of five water molecules is remarkably conserved throughout the biological range of cytochrome f from cyanobacteria to plants [martinez et al. (1994) structure 2, 95-105]. structure and seque ...199910423236
a galinstan expansion femtosyringe for microinjection of eukaryotic organelles and prokaryotes.a galinstan expansion femtosyringe enables femtoliter to attoliter samples to be introduced into prokaryotes and subcellular compartments of eukaryotes. the method uses heat-induced expansion of galinstan (a liquid metal alloy of gallium, indium, and tin) within a glass syringe to expel samples through a tip diameter of about 0.1 microm. the narrow tip inflicts less damage than conventional capillaries, and the heat-induced expansion of the galinstan allows fine control over the rate of injectio ...199910471935
the sip(sli) gene of streptomyces lividans tk24 specifies an unusual signal peptidase with a putative c-terminal transmembrane anchor.type i signal peptidases (spases) are a widespread family of enzymes which remove signal peptides from proteins translocated across cellular membranes. here, we report the first isolation of a gene coding for type i signal peptidase of streptomyces, denoted sip(sli). the sip(sli) gene specifies a protein of 291 amino acids. thus sip(sli) is much larger (approximately 100 amino acids) than other known spases of gram-positive bacteria and resembles spases of gram-negative bacteria, showing the hig ...199810520736
inhibition of croton oil-induced oedema in mice ear skin by capsular polysaccharides from cyanobacteria.the anti-inflammatory properties of hydrophilic extracts of the capsular polymers of twelve cyanobacterial strains belonging to the genera phormidium and nostoc from marine and terrestrial habitats were tested topically on croton oil-induced oedema in mice ear skin. the screening program identified several strains as producers of anti-inflammatory products (up to 56% inhibition of the oedema). the inhibition response was dose-dependent. the application of trichloroacetic acid-treated extracts re ...200010763863
purification and characterization of a novel lectin from a freshwater cyanobacterium, oscillatoria agardhii.in the survey of 14 species of laboratory-cultured cyanobacteria for hemagglutinins, we newly detected the activity in two species, oscillatoria agardhii, strain nies-204, and phormidium foveolarum, strain nies-503. from the extract of o. agardhii, which showed the highest activity with trypsin-treated erythrocytes of rabbit, a lectin was purified to homogeneity by the combination of precipitation with (nh4)2so4, gel filtration, hydrophobic chromatography and reverse phase chromatography. the pu ...200010817903
tryptophan-heme pi-electrostatic interactions in cytochrome f of oxygenic photosynthesis.cytochrome f of oxygenic photosynthesis has an unprecedented structure, including the n-terminus being a heme ligand. the adjacent n-terminal heme-shielding domain is enriched in aromatic amino acids. the atomic structures of the chloroplast and cyanobacterial cytochromes f were compared to explain spectral and redox differences between them. the conserved aromatic side chain in the n-terminal heme-shielding peptide at position 4, phe and tyr in plants and algae, respectively, and trp in cyanoba ...200010821668
[the isolation, purification and cloning of the psm1 plasmid from the cyanobacterium plectonema boryanum].three methods of plasmids isolation from the cells of cyanobacteria: plectonema boryanum 465, p. nostocorum 636, p. nostocorum 638, p. edaphicum 262, plectonema sp. 456, phormidium uncinatum 528, anabaena variabilis 458 and synechococcus cedrorum 750 have been approved. the method of plasmids isolation by 1 m nacl salting out was used for plasmid screening. all the strains studied contained large, above 55 kb plasmids, small plasmids (1.5 kb) were found in the cells of p. boryanum 465 and p. nos ...200010872285
[cyanobacteria as indicators of organic contamination].in two costa rican rivers used as receptors for domestic sewage, treated by primary stabilization ponds, were taken a total of 28 samplings located at the pond exit and at three different sites in each river: 100 m before the ponds discharge, at the discharge and 100 m after the discharge. these sampling were done for a five and a half years including dry and rainy seasons. in each sampling site, samples were collected of five different substrates: stones, submerge and semi submerge vegetation, ...199910883326
phylogenetic and morphological diversity of cyanobacteria in soil desert crusts from the colorado plateau.we compared the community structures of cyanobacteria in four biological desert crusts from utah's colorado plateau developing on different substrata. we analyzed natural samples, cultures, and cyanobacterial filaments or colonies retrieved by micromanipulation from field samples using microscopy, denaturing gradient gel electrophoresis, and sequencing of 16s rrna genes. while microscopic analyses apparently underestimated the biodiversity of thin filamentous cyanobacteria, molecular analyses fa ...200111282648
use of artificial neural network in the prediction of algal blooms.a model to quantify the interactions between abiotic factors and algal genera in lake kasumigaura, japan was developed using artificial neural network technology. results showed that the timing and magnitude of algal blooms of microcystis, phormidium and synedra in lake kasumigaura could be successfully predicted. as for the newly occurring dominant oscillatoria, results were not satisfactory. the evaluation of the importance of factors showed that microcystis, phormidium, oscillatoria and syned ...200111337850
mesophilic cyanobacteria producing thermophilic restriction endonucleases.when searching for the site-specific endonucleases in several strains of phormidium we made the following observations. among the 16 strains that originated from 15 species of phormidium, 12 produced one or more restriction enzymes, of which two produced the highly thermophilic restriction endonucleases ptai and ppaaii with their optimum activity at 65-80 degrees c, which is far above the lethal temperature for the host microorganism (40 degrees c). these two temperature-resistant enzymes are is ...200111430404
paleobiology of the mesoproterozoic-neoproterozoic transition: the sukhaya tunguska formation, turukhansk uplift, siberia.silicified carbonates of the latest mesoproterozoic sukhaya tunguska formation, northwestern siberia, contain abundant and diverse permineralized microfossils. peritidal environments are dominated by microbial mats built by filamentous cyanobacteria comparable to modern species of lyngbya and phormidium. in subtidal to lower intertidal settings, mat-dwelling microbenthos and possible coastal microplankton are abundant. in contrast, densely woven mat populations with few associated taxa character ...199711541434
the occurrence of cyanobacteria in pulp and paper waste-treatment systems.pulp and paper secondary waste-treatment systems in brazil, canada, new zealand, and the u.s.a. contained dynamic cyanobacterial communities, some of which exceeded heterotrophic bacterial biomass. no other viable photoautotrophic populations were detected in the ponds. regardless of geographical location, oscillatoriales including phormidium, geitlerinema, and pseudanabaena were the dominant taxa. as well, chroococcus (chroococcales) was an important genus in brazil and new zealand. the possibl ...200111575503
hydrophobic interactions in a cyanobacterial plastocyanin-cytochrome f complex.the complex of the photosynthetic redox partners plastocyanin and cytochrome f from the thermophilic cyanobacterium, phormidium laminosum, was investigated by nuclear magnetic resonance (nmr). chemical-shift perturbation analysis of amide proton and nitrogen nuclei implicates the hydrophobic patch and, to a lesser extent, the "eastern face" of plastocyanin in the complex interface. intermolecular pseudocontact shifts observed in the complex of cadmium-substituted plastocyanin and ferric cytochro ...200111673974
[physical mapping of plasmid psm1 of the cyanobacterium plectonema boryanum gom. strain calu 465].a physical map of plasmid psm1 has been compiled as a result of restriction analysis of pbsmi isolated from the cells of cyanobacterium plectonema boryanum 465. a comparative analysis of the restriction sites localization in dna of plasmid psm1 with site topology of plasmids pgl3 of p. boryanum and ppf1 of phormidium foveolarum indicates to high degree of these plasmids homology.200111692681
physical, chemical, and microbiological characteristics of microbial mats (kopara) in the south pacific atolls of french polynesia.microbial mats that develop in shallow brackish and hyposaline ponds in the rims of two french polynesian atolls (rangiroa and tetiaroa) were intensively investigated during the past three years. comparative assessment of these mats (called kopara in polynesian language) showed remarkable similarities in their composition and structure. due to the lack of iron, the color of the cyanobacterial pigments produced remained visible through the entire depth of the mats (20-40 cm depth), with alternate ...200111766060
preliminary evidence of toxicity associated with the benthic cyanobacterium phormidium in south australia.in april 2000, the water supply for yorke peninsula in south australia was deemed non-potable when extracts from a proliferation of the benthic cyanobacterium phormidium aff. formosum in upper paskeville reservoir were found to be lethally toxic by intraperitoneal injection into mice (400 mg kg-1). routine water quality monitoring had failed to detect the development of the phormidium until complaints of musty taste and odour, attributable to the production of 2-methyl-isoborneol (mib), were rec ...200111769248
role of electrostatics in the interaction between cytochrome f and plastocyanin of the cyanobacterium phormidium laminosum.the role of charged residues on the surface of plastocyanin from the cyanobacterium phormidium laminosum in the reaction with soluble cytochrome f in vitro was studied using site-directed mutagenesis. the charge on each of five residues on the eastern face of plastocyanin was neutralized and/or inverted, and the effect of the mutation on midpoint potentials was determined. the dependence of the overall rate constant of reaction, k(2), on ionic strength was investigated using stopped-flow spectro ...200211876635
cyanobacterial flora and the physico-chemical environment of six tropical fresh water lakes of udaipur, india.the cyanobacteria and physico-chemical environments of six tropical fresh water lakes of udaipur, india were investigated. these lakes receive varying nutrient inputs from different sources. altogether 51 species of cyanobacteria were recorded. species composition varied between lakes and between seasons. lake vi (baghdara), which receives nutrients from natural sources only, differed considerably from the others in water chemistry and composition of dominant species. lake ii (swaroop sagar), eu ...200211887319
microbial diversity of a heavily polluted microbial mat and its community changes following degradation of petroleum compounds.we studied the microbial diversity of benthic cyanobacterial mats inhabiting a heavily polluted site in a coastal stream (wadi gaza) and monitored the microbial community response induced by exposure to and degradation of four model petroleum compounds in the laboratory. phormidium- and oscillatoria-like cyanobacterial morphotypes were dominant in the field. bacteria belonging to different groups, mainly the cytophaga-flavobacterium-bacteriodes group, the gamma and beta subclasses of the class p ...200211916684
increased tolerance to thermal inactivation of oxygen evolution in spinach photosystem ii membranes by substitution of the extrinsic 33-kda protein by its homologue from a thermophilic cyanobacterium.photosynthetic oxygen evolution is an extremely heat-sensitive process and incubation of spinach photosystem ii (psii) membranes at 40 degrees c for only several minutes leads to its complete inactivation. substitution experiments of the spinach 33-kda manganese stabilizing protein by a homologue protein, isolated either from the thermophilic cyanobacterium phormidium laminosum, or from escherichia coli as a recombinant thermophilic cyanobacterial protein, showed a significant increase in tolera ...200212034468
characterization of the bacterial consortium associated with black band disease in coral using molecular microbiological techniques.the bacterial community associated with black band disease (bbd) of the scleractinian corals diploria strigosa, montastrea annularis and colpophyllia natans was examined using culture-independent techniques. two complementary molecular screening techniques of 16s rdna genes [amplified 16s ribosomal dna restriction analysis (ardra) of clone libraries and denaturing gradient gel electrophoresis (dgge)] were used to give a comprehensive characterization of the community. findings support previous s ...200212123476
the ternary complex of cytochrome f and cytochrome c: identification of a second binding site and competition for plastocyanin binding.the complex of yeast cytochrome c and cytochrome f from the cyanobacterium phormidium laminosum was investigated by nmr spectroscopy. chemical shift perturbation analysis reveals that residues around the haem edge of cytochrome c are involved in the complex interface. binding curves derived from an nmr spectroscopy titration at 10 mm ionic strength indicate that there are two sites for cytochrome c with binding constants of approximately 2 x 10(4) m(-1) and 4 x 10(3) m(-1). a protein docking sim ...200212325008
the interactions of cyanobacterial cytochrome c6 and cytochrome f, characterized by nmr.during oxygenic photosynthesis, cytochrome c(6) shuttles electrons between the membrane-bound complexes cytochrome bf and photosystem i. complex formation between phormidium laminosum cytochrome f and cytochrome c(6) from both anabaena sp. pcc 7119 and synechococcus elongatus has been investigated by nuclear magnetic resonance spectroscopy. chemical-shift perturbation analysis reveals a binding site on anabaena cytochrome c(6), which consists of a predominantly hydrophobic patch surrounding the ...200212356767
structure and absolute stereochemistry of phormidolide, a new toxic metabolite from the marine cyanobacterium phormidium sp.the extract from a laboratory culture of an indonesian isolate of the cyanobacterium phormidium sp. displayed inhibitory activity in a ras-raf protein interaction assay. assay-guided fractionation led to the isolation of both active and inactive materials of novel structure. the major inactive metabolite, phormidolide, was nevertheless highly toxic to brine shrimp (lc(50) = 1.5 microm), and hence, its structure was elucidated using various spectroscopic methods, primarily nmr. a series of partia ...200212423120
role of electrostatics in the interaction between plastocyanin and photosystem i of the cyanobacterium phormidium laminosum.the interactions between photosystem i and five charge mutants of plastocyanin from the cyanobacterium phormidium laminosum were investigated in vitro. the dependence of the overall rate constant of reaction, k2, on ionic strength was investigated using laser flash photolysis. the rate constant of the wild-type reaction increased with ionic strength, indicating repulsion between the reaction partners. removing a negative charge on plastocyanin (d44a) accelerated the reaction and made it independ ...200212444978
cyanobacteria associated with anopheles albimanus (diptera: culicidae) larval habitats in southern mexico.cyanobacteria associated with anopheles albimanus wiedemann larval habitats from southern chiapas, mexico, were isolated and identified from water samples and larval midguts using selective medium bg-11. larval breeding sites were classified according to their hydrology and dominant vegetation. cyanobacteria isolated in water samples were recorded and analyzed according to hydrological and vegetation habitat breeding types, and mosquito larval abundance. in total, 19 cyanobacteria species were i ...200212495179
bioremediation of oil by marine microbial mats.cyanobacterial mats developing in oil-contaminated sabkhas along the african coasts of the gulf of suez and in the pristine solar lake, sinai, were collected for laboratory studies. samples of both mats showed efficient degradation of crude oil in the light, followed by development of an intense bloom of phormidium spp. and oscillatoria spp. isolated cyanobacterial strains, however, did not degrade crude oil in axenic cultures. strains of sulfate-reducing bacteria and aerobic heterotrophs were c ...200212497184
plastocyanin-cytochrome f interactions: the influence of hydrophobic patch mutations studied by nmr spectroscopy.transient complex formation between plastocyanin from prochlorothrix hollandica and cytochrome f from phormidium laminosum was investigated using nuclear magnetic resonance (nmr) spectroscopy. binding curves derived from nmr titrations at 10 mm ionic strength reveal a 1:1 stoichiometry and a binding constant of 6 (+/-2) x 10(3) m(-1) for complex formation, 1 order of magnitude larger than that for the physiological plastocyanin-cytochrome f complex from ph. laminosum. chemical-shift perturbation ...200212501198
microbial spheres: a novel cyanobacterial-diatom symbiosis.cyanobacteria, algae and bacteria are widespread inhabitants of north sea microbial mats. our studies of these populations showed uncommon modes of living and extraordinary structures, which have not been described before. the structures are spherical objects covering a community of cyanobacteria, diatoms and bacteria. the cultivation of these communities in the laboratory and intensive observations of their exceptional movement has led to some spectacular findings. the sphere formations go thro ...200312649756
alanine dehydrogenase from the psychrophilic bacterium strain pa-43: overexpression, molecular characterization, and sequence analysis.the gene encoding alanine dehydrogenase (aladh; ec 1.4.1.1) from the marine psychrophilic bacterium strain pa-43 was cloned, sequenced, and overexpressed in escherichia coli. the primary structure was deduced on the basis of the nucleotide sequence. the enzyme subunit contains 371 amino acid residues, and the sequence is 90% and 77% identical, respectively, to aladhs from shewanella ac10 and vibrio proteolyticus. the half-life of pa-43 aladh at 52 degrees c is 9 min, and it is thus more thermola ...200312664266
cyanobacteria associated with coral black band disease in caribbean and indo-pacific reefs.for 30 years it has been assumed that a single species of cyanobacteria, phormidium corallyticum, is the volumetrically dominant component of all cases of black band disease (bbd) in coral. cyanobacterium-specific 16s rrna gene primers and terminal restriction fragment length polymorphism analyses were used to determine the phylogenetic diversity of these bbd cyanobacteria on coral reefs in the caribbean and indo-pacific seas. these analyses indicate that the cyanobacteria that inhabit bbd bacte ...200312676731
relation between interface properties and kinetics of electron transfer in the interaction of cytochrome f and plastocyanin from plants and the cyanobacterium phormidium laminosum.cytochrome f and plastocyanin from the cyanobacterium phormidium laminosum react an order of magnitude faster than their counterparts from chloroplasts when long-range electrostatic interactions have been screened out by high salt concentration [schlarb-ridley, b. g., et al. (2002) biochemistry 41, 3279-3285]. to investigate the relative contributions of the reaction partners to these differences, the reactions of turnip cytochrome f with p. laminosum plastocyanin and p. laminosum cytochrome f w ...200312680759
[mats of microcoleus from alkaliphilic and halophilic communities].a detailed description of the macrostructure, the ultrastructure, and the species diversity of alkaliphilic mat from lake khilganta (buryatiya) is presented. the structure of this mat was found to be similar to that of halophilic mats from hypersaline lagoons of lake sivash (crimea) that we studied earlier. microcoleus chthonoplastes was the dominant form of cyanobacteria in both mats (in the alkaliphilic mat, phormidium molle was another dominant form). both mats had a pronounced laminated stru ...200312698797
[associative cyanobacteria isolated from the roots of epiphytic orchids].associative cyanobacteria were isolated from the rhizoplane and velamen of the aerial roots of the epiphytic orchids acampe papillosa, phalaenopsis amabilis, and dendrobium moschatum and from the substrate roots of acampe papillosa and dendrobium moschatum. cyanobacteria were isolated on complete and nitrogen-free variants of bg-11 medium. on all media and in all samples, cyanobacteria of the genus nostoc predominated. nostoc, anabaena, and calothrix were isolated from the surface of the a. papi ...200312698800
role of charges on cytochrome f from the cyanobacterium phormidium laminosum in its interaction with plastocyanin.the role of charge on the surface of cytochrome f from the cyanobacterium phormidium laminosum in the reaction with plastocyanin was investigated in vitro using site-directed mutagenesis. charge was neutralized at five acidic residues individually and introduced at a residue close to the interface between the two proteins. the effects on the kinetics of the reaction were measured using stopped-flow spectrophotometry, and the midpoint potentials of the mutant proteins were determined. the depende ...200312718523
characterization of aspartate aminotransferase from the cyanobacterium phormidium lapideum.aspartate aminotransferase (aspat) was purified to homogeneity from cell extracts of the non-n2-fixing cyanobacterium phormidium lapideum. the nh2-terminal sequence of 25 amino acid residues was different from the sequences of the subfamily ialpha of aspats from eukaryotes and escherichia coli, but it was similar to sequences of the subfamily igamma of aspats from archaebacteria and eubacteria. the enzyme was most active at 80 degrees c and was stable at up to 75 degrees c. thermal inactivation ...200312723595
[the structure and biogeochemical activity of the phototrophic communities from the bol'sherechenskii alkaline hot spring].microbial communities growing in the bed of the alkaline, sulfide hot spring bol'sherechenskii (the baikal rift area) were studied over many years (1986-2001). the effluent water temperature ranged from 72 to 74 degrees c, ph was from 9.25 to 9.8, and sulfide content was from 12 to 13.4 mg/ml. simultaneous effects of several extreme factors restrict the spread of phototrophic microorganisms. visible microbial fouling appears with a decrease in the temperature to 62 degrees c and in the sulfide c ...200312751248
detection of short-lived transient protein-protein interactions by intermolecular nuclear paramagnetic relaxation: plastocyanin from anabaena variabilis.an nmr approach is presented that provides detailed information about short-lived, transient interactions between protein molecules in solution. the approach is based on the longitudinal paramagnetic relaxation rates of the protein nuclei and requires that at least one of the interacting molecules is paramagnetic. the specific interactions are monitored by the intermolecular paramagnetic contribution to the relaxation of protons at or close to the interaction surface. by applying the approach to ...200312783525
phormidium animalis (cyanobacteria: oscillatoriaceae) supports larval development of anopheles albimanus.the capability of phormidium animalis, a cyanobacterium commonly found in larval habitats of anopheles albimanus in southern mexico, to support larval development of this mosquito was investigated. first-stage larvae were reared under insectary conditions with p. animalis ad libitum and their development was compared with larvae fed with wheat germ. the time of pupation and adult mosquito size, assessed by wing length, were similar in both groups, but fewer adult mosquitoes were obtained from la ...200312825668
[glucides of phormidium tenue]. 195313067276
[cytology of cyanophycea. i. research on the substructure of phormidium uncinatum gom]. 195613327991
[cytology of cyanophycea. ii. centroplasm and granular inclusions of phormidium uncinatum]. 195613327992
artificial cultivation of a red-pigmented marine blue-green alga, phormidium persicinum. 195813525639
chemical analysis of a mucopolymer component in cell walls of the blue-green alga phormidium uncinatum. 196213894623
algal virus: isolation.freshwater blue-green algae of the genera lyngbya, plectonema, and phormidium are susceptible to a virus recently isolated from a waste-stabilization pond. electron micrographs of a partially purified preparation show that the viral particle has an icosahedral structure about 66 mmicro in diameter.196313976026
viability of dried vegetative cells or filaments, survivability and/or reproduction under water and light stress, and following heat and uv exposure in some blue-green and green algae.vegetative cells in dried, mucilagenous mass of gloeocapsa aeruginosa and aphanothece nidulans, reticulum of hydrodictyon reticulatum, mucilagenous mass of chroococcus minor, and filaments of oedogonium sp. and scytonema hofmanni died within 1/2, 1/2, 1/2, 1, 3 and 6 h, respectively, while dried vegetative filaments of phormidium foveolarum retained under similar storage conditions viability for 4 d. p. foveolarum tolerated 1 mol/l nacl. the resistance to desiccation in p. foveolarum exhibited s ...200314533482
characterization of the n-terminal domain of nrtc, the atp-binding subunit of abc-type nitrate transporter of the cyanobacterium phormidium laminosum.the n-terminal domain of nrtc, the atp-binding subunit of nitrate/nitrite abc-transporter in the cyanobacterium phormidium laminosum, has been expressed in escherichia coli as a histidine-tagged fusion protein (his(6)nrtc1). binding of atp to the pure his(6)nrtc1 was characterized using the nucleotide analogue tnp-atp [2'(3')-o-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate]. fluorescence assays showed that his(6)nrtc1 specifically binds mg(2+) tnp-atp with high affinity, binding being depende ...200314572912
detection, isolation, and characterization of exopolysaccharide produced by a strain of phormidium 94a isolated from an arid zone of mexico.phormidium 94a, a cyanobacteria that produces extracellular polymeric substances (eps), was isolated from arid soils of mexico. microscopic localization, using histochemical techniques like the toluidine blue technique, was done in order to demonstrate the presence of eps. acetone was added to precipitate the eps. in this study we characterized the eps by gc, hplc, and ir techniques. the highest fraction of eps had a molecular weight of 2000 kda. the sugar composition was galactose, mannose, gal ...200414748086
strategy to obtain axenic cultures from field-collected samples of the cyanobacterium phormidium animalis.an efficient strategy, based on a combination of procedures, was developed to obtain axenic cultures from field-collected samples of the cyanobacterium phormidium animalis. samples were initially cultured in solid asn-10 medium, and a crude separation of major contaminants from p. animalis filaments was achieved by washing in a series of centrifugations and resuspensions in liquid medium. then, manageable filament fragments were obtained by probe sonication. fragmentation was followed by forcefu ...200415003694
determination of nitrogen-fixing phylotypes in lyngbya sp. and microcoleus chthonoplastes cyanobacterial mats from guerrero negro, baja california, mexico.in many environments, biological nitrogen fixation can alleviate nitrogen limitation. the high rates of n(2) fixation often observed in cyanobacterial mats suggest that n(2) fixation may be an important source of n. in this study, organisms expressing nifh were identified in a lyngbya sp.- and two microcoleus chthonoplastes-dominated cyanobacterial mats. the pattern of nitrogenase activity was determined for the lyngbya sp. mat and a microcoleus chthonoplastes mat sampled directly in guerrero ne ...200415066804
ecosystems on ice: the microbial ecology of markham ice shelf in the high arctic.microbial communities occur throughout the cryosphere in a diverse range of ice-dominated habitats including snow, sea ice, glaciers, permafrost, and ice clouds. in each of these environments, organisms must be capable of surviving freeze-thaw cycles, persistent low temperatures for growth, extremes of solar radiation, and prolonged dormancy. these constraints may have been especially important during global cooling events in the past, including the precambrian glaciations. one analogue of these ...200415094087
species specificity of musty odor producing phormidium tenue in lake kamafusa.16s ribosomal dna sequences of various strains of phormidium tenue (p. tenue) in lake kamafusa were determined. such p. tenue could not be distinguished under microscopic examination. from the results of the analyses of base sequences, and using a phylogenetic tree, several p. tenue with different species specificity on the sequence were found in the lake. p. tenue were divided into three groups. the first produced 2-methylisoborneol (mib) and was close to a species from the moat of nagoya castl ...200415237605
structure of alanine dehydrogenase from archaeoglobus: active site analysis and relation to bacterial cyclodeaminases and mammalian mu crystallin.the hyperthermophilic archaeon archaeoglobus fulgidus contains an l-ala dehydrogenase (aladh, ec 1.4.1.1) that is not homologous to known bacterial dehydrogenases and appears to represent a previously unrecognized archaeal group of nad-dependent dehydrogenases. the gene (genbank; tigr af1665) was annotated initially as an ornithine cyclodeaminase (ocd) on the basis of strong homology with the mu crystallin/ocd protein family. we report the structure of the nad-bound af1665 aladh (af-aladh) at 2. ...200415313611
a brownian dynamics study of the interaction of phormidium laminosum plastocyanin with phormidium laminosum cytochrome f.the interaction of phormidium laminosum plastocyanin (pc) with p. laminosum cytochrome f (cyt f) was studied using brownian dynamics (bd) simulations. few complexes and a low rate of electron transfer were observed for wild-type pc. increasing the positive electrostatic field on pc by the addition of a zn(2+) ion in the neighborhood of d44 and d45 on pc (as found in crystal structure of plastocyanin) increased the number of complexes formed and the calculated rates of electron transfer as did pc ...200415345580
a thermal unfolding study of plastocyanin from the thermophilic cyanobacterium phormidium laminosum.the thermal unfolding of the plastocyanin from phormidium laminosum, a thermophilic cyanobacterium, is herein described. the main objective of this work is to identify structural factors responsible for the higher stability observed in proteins from thermophilic organisms. with the aid of fluorescence spectroscopy, epr, and nmr, the factors influencing the unfolding process of the protein were investigated, and procedures for its study have been standardized. the different spectroscopic techniqu ...200415544349
cyanobacteria in antarctica: ecology, physiology and cold adaptation.cyanobacterial species composition of fresh water and terrestrial ecosystems and chemical environment of water in schirmacher oasis in continental antarctica was investigated. over 35 species of cyanobacteria were recorded. diazotrophic species both heterocystous and unicellular contributed more than half to the count except in lake ecosystem. the species composition varied among the fresh water as well as terrestrial ecosystems. the physico-chemical analyses of water revealed its poor nurient c ...200415559974
development of a universal microarray based on the ligation detection reaction and 16s rrna gene polymorphism to target diversity of cyanobacteria.the cyanobacteria are photosynthetic prokaryotes of significant ecological and biotechnological interest, since they strongly contribute to primary production and are a rich source of bioactive compounds. in eutrophic fresh and brackish waters, their mass occurrences (water blooms) are often toxic and constitute a high potential risk for human health. therefore, rapid and reliable identification of cyanobacterial species in complex environmental samples is important. here we describe the develop ...200415574913
structure of the complex between plastocyanin and cytochrome f from the cyanobacterium nostoc sp. pcc 7119 as determined by paramagnetic nmr. the balance between electrostatic and hydrophobic interactions within the transient complex determines the relative orientation of the two proteins.the complex between cytochrome f and plastocyanin from the cyanobacterium nostoc has been characterized by nmr spectroscopy. the binding constant is 16 mm(-1), and the lifetime of the complex is much less than 10 ms. intermolecular pseudo-contact shifts observed for the plastocyanin amide nuclei, caused by the heme iron, as well as the chemical-shift perturbation data were used as the sole experimental restraints to determine the orientation of plastocyanin relative to cytochrome f with a precis ...200515705583
molecular diversity of cyanobacteria inhabiting coniform structures and surrounding mat in a yellowstone hot spring.lithified coniform structures are common within cyanobacterial mats in yellowstone national park hot springs. it is unknown whether these structures and the mats from which they develop are inhabited by the same cyanobacterial populations. denaturing gradient gel electrophoresis and sequencing and phylogenetic analysis of 16s rdna was used to determine whether (1) three different morphological types of lithified coniform structures are inhabited by different cyanobacterial species, (2) these spe ...200515711172
different modes of interaction in cyanobacterial complexes of plastocyanin and cytochrome f.the highly efficient electron-transfer chain in photosynthesis demonstrates a remarkable variation among organisms in the type of interactions between the soluble electron-transfer protein plastocyanin and it partner cytochrome f. the complex from the cyanobacterium nostoc sp. pcc 7119 was studied using nuclear magnetic resonance spectroscopy and compared to that of the cyanobacterium phormidium laminosum. in both systems, the main site of interaction on plastocyanin is the hydrophobic patch. ho ...200515736928
purification and characterization of c-phycocyanin from cyanobacterial species of marine and freshwater habitat.the present paper describes an efficient single step chromatographic method for purification of c-phycocyanin from three cyanobacterial species, i.e., spirulina sp. (freshwater), phormidium sp. (marine water) and lyngbya sp. (marine water). c-phycocyanin from these cyanobacterial species was purified to homogeneity and some of their properties were investigated. the purification involves a multistep treatment of the crude extract by fractional precipitation with ammonium sulfate, followed by ion ...200515766866
biofilm formation by algae as a mechanism for surviving on mine tailings.photosynthetic biofilms successfully colonize the sediments of a mine tailings reservoir (guanajuato, mexico) despite the high metal concentrations that are present. to elucidate the mechanisms of biofilm survival despite metal ores, experiments were performed to evaluate the response of seminatural biofilms to cu, zn, and a combination of both metals at concentrations observed in the field. the biofilms were composed mostly of the chlorophyte chlorococcum sp. and the cyanobacterium phormidium s ...200515779756
toxic potential of five freshwater phormidium species (cyanoprokaryota).among the cyanoprokaryota (blue-green algae), the genus phormidium has thus far rarely been studied with respect to toxin production and potentially resulting human and environmental health effects. we here show that five previously unexplored freshwater species of this genus (ph. bijugatum, ph. molle, ph. papyraceum, ph. uncinatum, ph. autumnale) are indeed capable of producing bioactive compounds. phormidium extracts caused weight loss as well as neuro/hepatotoxic symptoms in mice, and in the ...200515804520
diversity within cyanobacterial mat communities in variable salinity meltwater ponds of mcmurdo ice shelf, antarctica.this study investigated the diversity of cyanobacterial mat communities of three meltwater ponds--fresh, orange and salt ponds, south of bratina island, mcmurdo ice shelf, antarctica. a combined morphological and genetic approach using clone libraries was used to investigate the influence of salinity on cyanobacterial diversity within these ecosystems without prior cultivation or isolation of cyanobacteria. we were able to identify 22 phylotypes belonging to phormidium sp., oscillatoria sp. and ...200515816929
textile dye decolorization using cyanobacteria.cyanobacterial cultures isolated from sites polluted by industrial textile effluents were screened for their ability to decolorize cyclic azo dyes. gloeocapsa pleurocapsoides and phormidium ceylanicum decolorized acid red 97 and ff sky blue dyes by more than 80% after 26 days. chroococcus minutus was the only culture which decolorized amido black 10b (55%). chlorophyll a synthesis in all cultures was strongly inhibited by the dyes. visible spectroscopy and tlc confirmed that color removal was du ...200515834793
implications of the effects of viscosity, macromolecular crowding, and temperature for the transient interaction between cytochrome f and plastocyanin from the cyanobacterium phormidium laminosum.the reaction between cytochrome f and plastocyanin is a central feature of the photosynthetic electron-transport system of all oxygenic organisms. we have studied the reaction in solution to understand how the very weak binding between the two proteins from phormidium laminosum can nevertheless lead to fast rates of electron transfer. in a previous publication [schlarb-ridley, b. g., et al. (2003) biochemistry 42, 4057-4063], we suggested that the reaction is diffusion-controlled because of a st ...200515835911
benthic cyanobacteria from the baltic sea contain cytotoxic anabaena, nodularia, and nostoc strains and an apoptosis-inducing phormidium strain.benthic cyanobacteria from aquatic environments have been reported to produce biologically active metabolites. however, the toxicity and other biological activities of benthic cyanobacteria from the baltic sea are not well known. we determined the biological activities of 21 anabaena, calothrix, nodularia, nostoc, and phormidium strains isolated from benthic littoral habitats of the baltic sea. we studied whether benthic cyanobacterial extracts caused cytotoxicity by necrosis or induced apoptosi ...200515892066
first report in a river in france of the benthic cyanobacterium phormidium favosum producing anatoxin-a associated with dog neurotoxicosis.the first identification of anatoxin-a in a french lotic system is reported. rapid deaths of dogs occurred in 2003 after the animals drank water from the shoreline of the la loue river in eastern france. sediments, stones and macrophytes surfaces at the margin of the river were covered by a thick biofilm containing large quantities of several benthic species of filamentous, non-heterocystous cyanobacteria. known cyanotoxins, such as microcystins, saxitoxins and anatoxins were screened from biofi ...200515904687
community phylogenetic analysis of moderately thermophilic cyanobacterial mats from china, the philippines and thailand.most community molecular studies of thermophilic cyanobacterial mats to date have focused on synechococcus occurring at temperatures of approximately 50-65 degrees c. these reveal that molecular diversity exceeds that indicated by morphology, and that phylogeographic lineages exist. the moderately thermophilic and generally filamentous cyanobacterial mat communities occurring at lower temperatures have not previously been investigated at the community molecular level. here we report community di ...200515970994
irradiance regulation of photosynthesis and respiration in modern marine microbialites built by benthic cyanobacteria in a tropical lagoon (new caledonia).microbialites are organosedimentary deposits that have built up as a result of the growth and binding of detrital sediment by a benthic microbial community. this study focuses on microbialites built by monospecific populations of cyanobacteria in the south-west lagoon of new caledonia, where they have been observed down to 20-25 m depth. the aim was to study their photosynthetic and respiratory responses to various light intensities. the phormidium sp. tk1 microbialite was collected at 19 m dept ...200516052382
role of cyanobacteria in the biodegradation of crude oil by a tropical cyanobacterial mat.cyanobacterial mats are ubiquitous in tropical petroleum-polluted environments. they form a high biodiversity microbial consortium that contains efficient hydrocarbons degraders. a cyanobacterial mat collected from a petroleum-contaminated environment located in indonesia was studied for its biodegradation potential. in the field, the natural mat was shown to degrade efficiently the crude oil present in the environment. this natural mat demonstrated also a strong activity of degradation on model ...200616087213
effect of phytohormones on the growth dynamics and macromolecular contents of two extreme halophilic cyanobacteria (phormidium sps).two non-heterocystous, filamentous solar saltern extreme halophilic cyanobacteria viz., phormidium tenue and phormidium fragile were allowed to grow in different concentrations of phytohormones. among the phytohormones, indole-3 acetic acid and indole-3-butyric acid at 0. l ppm concentration enhanced the growth, pigments and carbohydrate content in p. fragile. the phycobiliprotein production was found higher at 0. l ppm concentration of indole-3-acetic acid in p. tenue, whereas indole-3-butyric ...200516114462
the impacts of cyanobacteria on pulp-and-paper wastewater toxicity and biodegradation of wastewater contaminants.this study investigated the effects of cyanobacteria from pulp-and-paper waste-treatment systems on biological toxicity removal and biodegradation of certain wastewater contaminants. in field and batch studies, using the microtox assay, cyanobacterial biomass and final wastewater toxicity were significantly correlated. in softwood-based wastewater, a decrease in toxicity was negatively correlated with cyanobacterial biomass, but the correlation was positive in hardwood-based wastewater. in the s ...200516175201
a brownian dynamics study of the interaction of phormidium cytochrome f with various cyanobacterial plastocyanins.brownian dynamics simulations were used to study the role of electrostatic forces in the interactions of cytochrome f from the cyanobacterium phormidium laminosum with various cyanobacterial plastocyanins. both the net charge on the plastocyanin molecule and the charge configuration around h92 (h87 in higher plants) are important in determining the interactions. those plastocyanins (pcs) with a net charge more negative than -2.0, including those from synechococcus sp. pcc7942, synechocystis sp. ...200616214856
cloning, structural analysis and expression of the gene encoding aspartate aminotransferase from the thermophilic cyanobacterium phormidium lapideum.the aspartate aminotransferase gene from the thermophilic cyanobacterium phormidium lapideum was cloned and expressed in escherichia coli. the orf of 1167 nucleotides encodes a protein of 388 amino acids having a molecular weight of 42,099. a molecular model of piaspat shows structural features similar to those of the thermus thermophilus aspat.200316233433
a comparative study of the thermal stability of plastocyanin, cytochrome c(6) and photosystem i in thermophilic and mesophilic cyanobacteria.cytochrome c(6) (cyt) from the thermophilic cyanobacterium phormidium laminosum has been purified and characterized. it is a mildly acidic protein, with physicochemical properties very similar to those of plastocyanin (pc). this is in agreement with the functional interchangeability of the two metalloproteins as electron donors to photosystem i (ps i). the kinetic analyses of the interaction of pc and cyt with photosystem i show that both metalloproteins reduce ps i with similar efficiencies, ac ...200116252173
community composition of a hypersaline endoevaporitic microbial mat.a hypersaline, endoevaporitic microbial community in eilat, israel, was studied by microscopy and by pcr amplification of genes for 16s rrna from different layers. in terms of biomass, the oxygenic layers of the community were dominated by cyanobacteria of the halothece, spirulina, and phormidium types, but cell counts (based on 4',6'-diamidino-2-phenylindole staining) and molecular surveys (clone libraries of pcr-amplified genes for 16s rrna) showed that oxygenic phototrophs were outnumbered by ...200516269778
characterization of functional bacterial groups in a hypersaline microbial mat community (salins-de-giraud, camargue, france).a photosynthetic microbial mat was investigated in a large pond of a mediterranean saltern (salins-de-giraud, camargue, france) having water salinity from 70 per thousand to 150 per thousand (w/v). analysis of characteristic biomarkers (e.g., major microbial fatty acids, hydrocarbons, alcohols and alkenones) revealed that cyanobacteria were the major component of the pond, in addition to diatoms and other algae. functional bacterial groups involved in the sulfur cycle could be correlated to thes ...200416329855
the distribution of cyanobacteria across physical and chemical gradients in hot springs in northern thailand.we mapped the distribution of mat forming cyanobacteria along the thermal gradient from 30 to 80 degrees c, in nine hot spring districts in northern thailand. nineteen genera and 36 species were identified by morphometric analysis. water temperature was the predominant determinant of community structure in the springs. the diversity of cyanobacterial morphotypes fell as temperature increased. water chemistry (ph, alkalinity and ammonia concentration) was a much weaker descriptor of the floral si ...200516329921
laboratory comparison of the effectiveness of several algicides on isolated swimming pool algae.the most frequently encountered species of algae found in swimming pools in the phoenix metropolitan area were used to evaluate the laboratory effectiveness of five commercially available pool chemicals used for algal control. the pool algae used were the xanthophyte pleurochloris pyrenoidosa, the chlorophyte oocystis sp., and the cyanophytes phormidium minnesotense and plectonema sp. pad algae kill (a chlorine derivative) was effective in the control of all test organisms. algaedyn, a silver-co ...198016345508
hydrophobicity as an adhesion mechanism of benthic cyanobacteria.the capacity of benthic cyanobacteria to adhere to solid substrates was examined in terms of their cell surface properties. by using a biphasic water-hydrocarbon test system, it was demonstrated that benthic cyanobacteria from divergent habitats were all hydrophobic, whereas all the planktonic cyanobacteria tested were hydrophilic. divalent cations were found more efficient than monovalent cations in effecting the expression of hydrophobicity. mechanical shearing of the cell surface, as well as ...198416346453
bacterial enhancement of vinyl fouling by algae.the role of bacteria in the development of algae on low-density vinyl was investigated. unidentified bacterial contaminants in unialgal stock cultures of phormidium faveolarum and pleurochloris pyrenoidosa enhanced, by 1 to 2 orders of magnitude, colonization of vinyl by these algae, as determined by epifluorescence microscopy counts and chlorophyll a in extracts of colonized vinyl. colonization by bacteria always preceded that by algae. scanning electron microscopy of the colonized phormidium-b ...198616347243
characterization of macromolecular flocculants produced by phormidium sp. strain j-1 and by anabaenopsis circularis pcc 6720.several benthic cyanobacteria were found to produce significant amounts of extracellular flocculants. the macromolecular flocculants produced by phormidium sp. strain j-1 and anabaenopsis circularis pcc 6720 were characterized. the phormidium flocculant is a sulfated heteropolysaccharide to which fatty acids and protein are bound. the polysaccharide backbone is composed of uronic acids, rhamnose, mannose, and galactose. the a. circularis flocculant is also an acidic polysaccharide containing ket ...198716347442
accumulation of trehalose and sucrose in cyanobacteria exposed to matric water stress.the drought-resistant cyanobacteria phormidium autumnale, strain lpp(4), and a chroococcidiopsis sp. accumulated trehalose, sucrose, and both trehalose and sucrose, respectively, in response to matric water stress. accumulated sugar concentrations reached values of up to 6.2 mug of trehalose per mug of chlorophyll in p. autumnale, 6.9 mug of sucrose per mug of chlorophyll in lpp(4), and 4.1 mug of sucrose and 3.2 mug of trehalose per mug of chlorophyll in the chroococcidiopsis sp. the same sugar ...199116348431
the nitrate/nitrite abc transporter of phormidium laminosum: phosphorylation state of nrta is not involved in its substrate binding activity.most cyanobacteria take up nitrate or nitrite through a multisubunit abc transporter (atp-binding cassette) located in the cytoplasmic membrane. nitrate and nitrite transport activity is instantaneously blocked by the presence of ammonium in the medium. previous biochemical studies reported the existence of phosphorylation/dephosphorylation events of the nitrate transporter (nrt) related to the presence of ammonium-sensitive kinase/phosphatase activities in plasma membranes of the cyanobacterium ...200616442736
crystallization of the photosystem i reaction centre.the reaction centre of the photosynthetic membrane complex photosystem i (psi) from the thermophilic cyanobacterium phormidium laminosum was found to crystallize under a range of conditions. the crystallization method, which can occur in the presence of larger detergent molecules than those used previously for the crystallization of membrane proteins, is presented in this report. several crystal forms have been observed, and some of these show birefringence and linear dichroism. optical measurem ...198716453774
investigation of the structure of trimeric and monomeric photosystem i reaction centre complexes.electron microscopy of monomeric and trimeric forms of the reaction centre of photosystem i from the thermophilic cyanobacterium phormidium laminosum has allowed the construction of a three-dimensional model describing the shape of the complex. the trimeric form of the photosystem i reaction centre complex was found to have a very regular shape corresponding to a rounded equilateral triangle with edges 18 nm long and a thickness of 6 nm. a distinctive chiral arrangement of the three reaction cen ...198816453855
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