Publications

detection and characterization of cyanobacterial nifh genes.	the dna sequence of a 359-bp fragment of nifh was determined for the heterocystous strains anabaena sp. strain ca (atcc 33047), nostoc muscorum utex 1933, a nostoc sp., gloeothece sp. strain atcc 27152, lyngbya lagerheimii utex 1930, and plectonema boryanum iu 594. results confirmed that the dna sequence of the 359-bp segment is sufficiently variable to distinguish cyanobacterial nifh genes from other eubacterial and arachaeobacterial nifh genes, as well as to distinguish heterocystous from nonh ...	1994	8161180
distinct and differently regulated mo-dependent nitrogen-fixing systems evolved for heterocysts and vegetative cells of anabaena variabilis atcc 29413: characterization of the fdxh1/2 gene regions as part of the nif1/2 gene clusters.	two different fdxh genes (fdxh1, fdxh2) have been isolated from the nitrogen-fixing, heterocyst-forming cyanobacterium anabaena variabilis atcc 29413. they are part of two different nif gene clusters, nif1 and nif2. fdxh1 encodes the [2fe-2s] ferredoxin that is known as the direct electron donor to nitrogenase in heterocysts, and is very similar to fdxh from anabaena sp. pcc 7120. fdxh2 has more residues in common and shares its oxygen sensitivity with the single fdxh from the non-heterocystous, ...	1995	8709854
[effect of reproduction of the lpp-3 cyanophage on glutamate dehydrogenase and glutamine synthetase activity in the cyanobacterium plectonema boryanum].	the effect of cyanophage lpp-3 reproduction on glutamate dehydrogenase and glutamine synthetase (gs) in p boryanum cells have been studied. it was determined that the both reactions are intensified by 135% and 220%, accordingly. isoenzymes of gs were purified from native and infected cell of cyanobacteria. their physical-and-chemical properties are different. the cyanophage development probably causes specific modification of the cell enzymes.	1995	8867309
tubercidin stabilizes microtubules against vinblastine-induced depolymerization, a taxol-like effect.	a sensitive assay for the detection of microtubule-stabilizing agents [1] was used to screen an extensive collection of cyanobacterial and microalgal extracts. the hydrophilic extract of the cyanobacterium, plectonema radiosum (uh isolate ic-70-1), exhibited microtubule-stabilizing activity. bioassay-directed purification of the active compound yielded tubercidin (7-deazaadenosine), a potent cytotoxic nucleoside analog. further studies revealed that tubercidin protected a population of cellular ...	1995	7585466
[alanine dehydrogenase of the cyanobacterium plectonema boryanum in the early period of cyanophage lpp-3 development].	it has been studied how reproduction of lpp-3 in plectonema boryanum cells influences the alanine dehydrogenase activity. it has been found that immediately after the virus adsorption the enzyme activity falls by 50% and the anabolic reaction is blocked. physicochemical properties of the enzyme vary as well. an infected cell has one isoenzyme-octamer with pl 9.1-9.2, ph-optimum by action 9-10, molecular weight about 27 kda.	1995	8553472
[alanine dehydrogenase from the cyanobacterium plectonema boryanum].	alanine dehydrogenase activity of plectonema boryanum cells was studied. it was found, that only nad(h) may be used as the coenzyme. kinetical parameters for substrates and coenzymes were determined. 2 ph-optima of action have been established for biosynthetic and anabolic reactions. two isoenzymes of adg were cleaned using the methods of ion-exchange chromatography and isoelectric focusing. some physical-chemical properties were studied: phopt--9-10 and 4.0; temperature optimum -40 degrees c; p ...	1995	8588252
[aspartate kinase from the cyanobacteriium plectonema boryanum infected with the cyanophage lpp-3].	the effect of development of cyanophage infection on the activity of aspartate kinase of plectonema boryanum has been studied. it has been determined that activity of aspartate kinase increased during early period of reproduction of cyanophage. it coincided in time with the increase of the level of amino acids of aspartate family. isoenzymes of aspartate kinase were isolated from the infected cells purified and studied. expression of viral genome is accompanied with the appearance of four new is ...	1995	8588253
characterization of four superoxide dismutase genes from a filamentous cyanobacterium.	by using an oligonucleotide probe constructed from a conserved region of amino acids located in the carboxyl-terminal end of superoxide dismutase (sod) proteins, four sod genes were cloned from the cyanobacterium plectonema boryanum utex 485. one of these genes, designated sodb, encoded an fesod enzyme, while the remaining three genes, designated soda1, soda2, and soda3, encoded mnsod enzymes. to investigate the expression of these four genes, total cellular rna was isolated from p. boryanum ute ...	1995	7860607
a novel nitrite reductase gene from the cyanobacterium plectonema boryanum.	the gene (nira) for nitrite reductase was cloned from the nonheterocystous, filamentous cyanobacterium plectonema boryanum. the predicted protein consists of 654 amino acids and has a calculated molecular weight of 72,135. the deduced amino acid sequence from positions 1 to 511 is strongly similar to the entire sequence of the ferredoxin-dependent nitrite reductases from other phototrophs, while the remainder of the protein is unique to the plectonema nitrite reductase. the c-terminal portion of ...	1995	7592378
identification of the chlb gene and the gene product essential for the light-independent chlorophyll biosynthesis in the cyanobacterium plectonema boryanum.	we cloned a 6.0-kb hindiii fragment from the cyanobacterium plectonema boryanum using the chloroplast chlb (orf513) gene of the liverwort (marchantia polymorpha) as a probe. an open reading frame (orf508) encoding a polypeptide of 508 amino acid residues was found within the nucleotide sequence of the 4,437-bp hindiii-ecorv subfragment. the deduced amino acid sequence of orf508 shows very high similarity to that encoded by the liverwort chlb gene (72.7%). a mutant, yfb14, in which orf508 was ina ...	1996	8673341
positive regulation by nitrite of the nitrate assimilation operon in the cyanobacteria synechococcus sp. strain pcc 7942 and plectonema boryanum.	in the absence of fixation of ammonium to glutamine, nitrate and nitrite activated transcription of the nitrate assimilation (nira-nrtabcd-narb) operon of synechococcus sp. strain pcc 7942. in a nitrate reductase-deficient mutant, only nitrite activated transcription, indicating that nitrite is the actual activator of the operon. nitrate and nitrite were also found to activate the transcription of a nitrate assimilation operon in the filamentous nonheterocystous nitrogen-fixing cyanobacterium pl ...	1996	8824636
observations on the mechanisms of attachment of some marine fouling blue-green algae.	using scanning electron microscopy (sem), differential interference contrast microscopy (dicm) and cytochemical staining techniques, preliminary observations have been made on the mechanisms of attachment of some common, marine, benthic fouling blue-green algae ("cyanobacteria") isolated into culture from various toxic and non-toxic surfaces in langstone harbour, south coast of england. blue-green algae investigated included species of calothrix, dermocarpa, plectonema, phormidium and xenococcus ...	1996	22115109
the heterocyst-specific fdxh gene product of the cyanobacterium anabaena sp. pcc 7120 is important but not essential for nitrogen fixation.	to clarify the role of the heterocyst-specific [2fe-2s] ferredoxin in cyanobacterial nitrogen fixation, mutational analysis of the anabaena 7120 fdxh gene region was carried out. first, the dna sequence of the wild-type 3509-bp ecori fragment downstream of the fdxh gene was determined. genes homologous to orf3 from the fdxh gene regions of a. variabilis and plectonema boryanum, the mop genes of clostridium pasteurianum encoding molybdo-pterin binding proteins, and orf3 from the a. variabilis hyd ...	1997	9079890
kinesin light chain in a eubacterium.	a eubacterial homolog of a kinesin light chain gene has been isolated and characterized from the cyanobacterium plectonema boryanum. although the eubacterial and eukaryotic kinesin light chains are highly similar in amino acid sequence, the eubacterial sequence differs in several distinguishing structural features, including the absence of a putative pest domain and the presence of additional highly conserved imperfect tandem repeats. two soluble kinesin light chain antigens have been identified ...	1997	9212172
periphyton as an indicator of water quality in the st lawrence river (québec, canada).	the performance of various algal indices to document improvements in water quality across a low nutrient concentration gradient was assessed during 2 years in the st lawrence river (quebec, canada). water-quality variables and periphyton samples were collected on navigational buoys near montreal during the spring, summer and fall of 1994 and 1995. exposure to urban wastewater varied widely within the sector surrounding the island of montreal, with some areas upstream receiving no direct effluent ...	1998	15093094
cloning of the gene encoding a protochlorophyllide reductase: the physiological significance of the co-existence of light-dependent and -independent protochlorophyllide reduction systems in the cyanobacterium plectonema boryanum.	cyanobacteria have two protochlorophyllide (pchlide) reductases catalyzing the conversion of pchlide to chlorophyllide, a key step in the biosynthetic pathway of chlorophylls (chls); a light-dependent (lpor) and a light-independent (dpor) reductase. we found an open reading frame (orf322) in a 2,131-bp ecori fragment from the genomic dna of the cyanobacterium plectonema boryanum. because the deduced amino acid sequence showed a high similarity to those of various plant lpors and the lpor activit ...	1998	9559561
acquisition of a new type of fructose-1,6-bisphosphatase with resistance to hydrogen peroxide in cyanobacteria: molecular characterization of the enzyme from synechocystis pcc 6803.	we have previously described that synechococcus pcc 7942 cells contain two fructose-1,6-bisphosphatase isozymes, designated f-i and f-ii the former belongs to a new type of fructose-1,6-bisphosphatase, while the latter is a typical enzyme similar to the cytosolic and chloroplastic forms from eukaryotic cells [tamoi et al., arch. biochem. biophys., 334, 1996, 27-36]. the genes of f-i and f-ii were found in three species of cyanobacteria, synechocystis pcc 6803, anabaena 7120, and plectonema borya ...	1998	9602137
multiple oligomeric forms of glucose-6-phosphate dehydrogenase in cyanobacteria and the role of opca in the assembly process.	multiple molecular forms of glucose-6-phosphate dehydrogenase (g6pdh) were detected by activity staining in non-denaturing polyacrylamide gels of cell-free extracts from a range of cyanobacteria including anabaena sp. pcc 7120, synechococcus sp. pcc 7942, plectonema boryanum pcc 73110, synechocystis sp. pcc 6803, nostoc sp. mac pcc 8009 and the marine strain synechococcus sp. wh7803. in most of the species tested, the profile of g6pdh activities was modulated by the growth of the cells in the pr ...	1998	9639925
clpb in a cyanobacterium: predicted structure, phylogenetic relationships, and regulation by light and temperature.	the sequence of a genomic clone encoding a 100-kda stress protein of plectonema boryanum (p-clpb) was determined. the predicted polypeptide contains two putative atpase regions located within two highly conserved domains (n1 and n2), a spacer region that likely forms a coiled-coil domain, and a highly conserved consensus ck2 phosphorylation domain. the coiled-coil region and the putative site of phosphorylation are not unique to p-clpb; they are present in all clpb sequences examined and are abs ...	1998	9748452
heavy metal uptake by polyphosphate bodies in living and killed cells of plectonema boryanum (cyanophycae).	the study was conducted to determine whether living or killed cell polyphosphate bodies (ppb) would sequester more of several heavy metals. living and heat- or glutaraldehyde-killed cells were exposed to 20 ppm of zn, pb, mn and al. air-dried cells on formvar-coated grids were first observed in the transmission electron microscope. the unit was then switched to the scanning transmission mode of operation with the spot setting. x-rays were collected on an energy dispersive x-ray spectrometer and ...	1998	10399343
surface charge density and light-scattering of the plectonema boryanum spheroplasts.	the electrokinetic properties of spheroplasts from the cyanobacterium plectonema boryanum were examined by particle microelectrophoresis technique. the electrophoretic mobility (epm) of the particles was determined after incubation with cacl2 in dependence of iron content in culture media as follows: an iron sufficient medium ('control' variant), an iron-deficient medium ('fe-starved' variant) and an excess of iron supply medium ('20 x fe' variant). strong increase in epm was observed with micro ...	1999	10228594
cloning and inactivation of genes encoding ferredoxin- and nadh-dependent glutamate synthases in the cyanobacterium plectonema boryanum. imbalances in nitrogen and carbon assimilations caused by deficiency of the ferredoxin-dependent enzyme	glutamate synthase (gogat) is a key enzyme in the assimilation of inorganic nitrogen in photosynthetic organisms. we found that, like higher plants, the facultative heterotrophic cyanobacterium plectonema boryanum had ferredoxin (fd)- and nadh-dependent gogats. the genes glsf, gltb, and gltd were cloned, and structural analyses and target mutageneses demonstrated that glsf encoded fd-gogat and that gltb and gltd encoded the two subunits of nadh-gogat. all three mutants lacking one of the gogat g ...	1999	10318681
differential expression of photosynthesis and nitrogen fixation genes in the cyanobacterium plectonema boryanum.	the filamentous non-heterocystous cyanobacterium plectonema boryanum fixes dinitrogen at a high rate during microaerobic growth in continuous illumination by temporal separation of oxygen-evolving photosynthesis and oxygen-sensitive dinitrogen fixation. the onset of nitrogen fixation is preceded by a depression in photosynthesis that establishes a sufficiently low level of dissolved oxygen in the growth medium. a several-fold reduction in the level of transcripts coding for phycocyanin (cpcba) a ...	2000	10712536
photosynthetic acclimation of the filamentous cyanobacterium, plectonema boryanum utex 485, to temperature and light.	photosynthetic acclimation to temperature and irradiance was studied in the filamentous, non-heterocystous cyanobacterium plectonema boryanum utex 485. growth rates of this cyanobacterium measured at ambient co2 were primarily influenced by temperature with minimal effects of irradiance. both growth temperature and irradiance affected linolenic (18:3) and linoleic acid (18:2) levels in the four major lipid classes in an independent but additive manner. in contrast, photosynthetic acclimation was ...	2000	10945347
excitation energy transfer from phycobilisomes to photosystems: a phenomenon associated with the temporal separation of photosynthesis and nitrogen fixation in a cyanobacterium, plectonema boryanum.	plectonema boryanum shows temporal separation of photosynthesis and nitrogen fixation under diazotrophic conditions. low temperature fluorescence studies have shown that in vivo the nitrogen fixing and photosynthesizing cells are adapted to 'state 2' and 'state 1', respectively. during nitrogen fixation phycobilisomes seem to transfer excitation energy to photosystem i whereas during oxygenic photosynthesis the energy is transferred to photosystem ii. the state 2 adapted n-phase cells failed to ...	2000	10924907
differential electron flow around photosystem i by two c(4)-photosynthetic-cell-specific ferredoxins.	in the c(4) plant maize (zea mays l.), two ferredoxin isoproteins, fd i and fd ii, are expressed specifically in mesophyll and bundle-sheath cells, respectively. cdnas for these ferredoxins were introduced separately into the cyanobacterium plectonema boryanum with a disrupted endogenous ferredoxin gene, yielding tm202 and km2-9 strains expressing fd i and fd ii. the growth of tm202 was retarded under high light (130 micromol/m(2)/s), whereas km2-9 grew at a normal rate but exhibited a nitrogen- ...	2000	11013207
excitation energy transfer from phycobilisomes to photosystems: a phenomenon associated with the temporal separation of photosynthesis and nitrogen fixation in a cyanobacterium, plectonema boryanum(1).	plectonema boryanum shows temporal separation of photosynthesis and nitrogen fixation under diazotrophic conditions. low temperature fluorescence studies have shown that in vivo the nitrogen fixing and photosynthesizing cells are adapted to 'state 2' and 'state 1', respectively. during nitrogen fixation phycobilisomes seem to transfer excitation energy to photosystem i whereas during oxygenic photosynthesis the energy is transferred to photosystem ii. the state 2 adapted n-phase cells failed to ...	2000	11004433
[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 ...	2000	10872285
protection of photosystem ii against uv-a and uv-b radiation in the cyanobacterium plectonema boryanum: the role of growth temperature and growth irradiance.	plectonema boryanum utex 485 cells were grown at 29 degrees c and 150 mumol m-2 s-1 photosynthetically active radiation (par) and exposed to par combined with ultraviolet-a radiation (uv-a) at 15 degrees c. this induced a time-dependent inhibition of photosystem ii (psii) photochemistry measured as a decrease of the chlorophyll a fluorescence ratio, fv/fm, to 50% after 2 h of uv-a treatment compared to nontreated control cells. exposure of the same cells to par combined with uv-a + ultraviolet-b ...	2000	11140265
therapeutical effect of modified adamantane copolymer compounds: study of molecular mechanisms.	copolymers of n-polyvinylpyrrolidone-acrylic acid (ab-1) and adamantane derivatives are known to possess marked antiviral activity in in vitro and in ovo models. among the constructed preparations of ab-1 modified by adamantane derivatives some, especially ab-4 (modified by deitiforin), were found to show more extended antiviral activity and to inhibit markedly virus reproduction in susceptible permissive cell cultures and chicken embryos. in ab-4 treated cells and allantoic sacs, virus titers ( ...	2001	11440176
quantitative analysis of the elemental composition and the mass of bacterial polyphosphate bodies using stem edx.	the quantitative analysis of laboratory grown organisms (plectonema boryanum and staphylococcus aureus) revealed that a typical in vivo polyphosphate body (ppb) contains o (4.3 x 10(-8) microg), c (1.2 x 10(-8) microg), p (6.7 x 10(-9) microg), mg (1.3 x 10(-9) microg), ca (6.7 x 10(-10) microg), k (6.7 x 10(-10) microg), fe (6.0 x 10(-10) microg), s (5.4 x 10(-10) microg) and al (5.9 x 10(-10) microg). quantitative x-ray analysis of samples from nature showed ppb contain o (1.63 x 10(-8) microg ...	2001	11522129
[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.	2001	11692681
degradation of crude oil by marine cyanobacteria.	the marine cyanobacteria oscillatoria salina biswas, plectonema terebrans bornet et flahault and aphanocapsa sp. degraded bombay high crude oil when grown in artificial seawater nutrients as well as in plain natural seawater. oil removal was measured by gravimetric and gas chromatographic methods. around 45-55% of the total fractions of crude oil (containing 50% aliphatics, 31% waxes and bitumin, 14% aromatics and 5% polar compounds) were removed in the presence of these cultures within 10 days. ...	2001	11759698
[construction of the shuttle vector psts1 and development of the method of its introduction into the cells of the cyanbacterium plectonema boryanum calu 465].	it has been shown that cells of trichoma cyanobacterium plectonema boryanum g o m. strain calu 465 do not possess natural resistance to antibiotics ampicyllin, chloramphenicol, streptomycin and canamycin. a shuttle vector psts1 has been constructed on the basis of cyanobacterial plasmid psm1 and vector pbr 322. conditions have been developed and conjugative transfer of psts1 to the cells of cyanobacterium p. boryanum has been performed. as the result of expression of beta-lactamase gene psts1 th ...	2001	11785421
[development of the method of rna labeling in vitro using the terminal transferase with the purpose to obtain hybridization probes].	a possibility to use terminal transferase to obtain hybridized rna-probes has been investigated. optimal conditions of the reaction proceeding were elaborated on the model objects--rna of the phage ms2: 200 mm of potassium cacodylate, ph 7.2, 1 mm cocl2, 1 mm dtt, under the considerable surplus of the enzyme. the elaborated method was used to determine the area of early genes of cyanophage lpp-3. with this purpose total rna preparations were isolated from cyanobacterium plectonema boryanum calu ...	2002	11944348
[use of cyanobacteria for indication of toxic action of stachybotrys toxins].	screening of cyanobacteria cultures for their sensitivity to the action of complex preparations of toxins from 18 strains of stachybotrys chartarum has been carried out with the purpose to search for new test-organisms to create a reliable system of biotesting of stachibotryotoxines. in contrast to other cultures of unicell (anacystis nidulans) and filamentous (anabaena sp., anabaena variabilis, nostoc linckia, plectonema boryanum) cyanobacteria used in the experiment, only one culture of unicel ...	2002	12436869
[comparative characteristics of physico-chemical and regulating properties of aspartate kinases from three species of cyanobacteria].	aspartokinases have been isolated from the cell-free extracts of plectonema boryanum, anabaena variabilis and synechococcus cedrorum. their physico-chemical characteristics and peculiarities of retroregulation by amino acids were studied. it has been shown that in p. boryanum cells aspartokinase reaction is catalyzed by only one enzyme, which is similar to the previously described bacterial origin enzymes. three izoenzymes, which differ in their main properties and amino acids-effectors, have be ...	2002	14964871
stoichiometry of the photosynthetic apparatus and phycobilisome structure of the cyanobacterium plectonema boryanum utex 485 are regulated by both light and temperature.	the role of growth temperature and growth irradiance on the regulation of the stoichiometry and function of the photosynthetic apparatus was examined in the cyanobacterium plectonema boryanum utex 485 by comparing mid-log phase cultures grown at either 29 degrees c/150 micromol m(-2) s(-1), 29 degrees c/750 micromol m(-2) s(-1), 15 degrees c/150 micromol m(-2) s(-1), or 15 degrees c/10 micromol m(-2) s(-1). cultures grown at 29 degrees c/750 micromol m(-2) s(-1) were structurally and functionall ...	2002	12428006
the presence of an iron-sulfur cluster in adenosine 5'-phosphosulfate reductase separates organisms utilizing adenosine 5'-phosphosulfate and phosphoadenosine 5'-phosphosulfate for sulfate assimilation.	it was generally accepted that plants, algae, and phototrophic bacteria use adenosine 5'-phosphosulfate (aps) for assimilatory sulfate reduction, whereas bacteria and fungi use phosphoadenosine 5'-phosphosulfate (paps). the corresponding enzymes, aps and paps reductase, share 25-30% identical amino acids. phylogenetic analysis of aps and paps reductase amino acid sequences from different organisms, which were retrieved from the genbank(tm), revealed two clusters. the first cluster comprised know ...	2002	11940598
arrest of chlorophyll synthesis and differential decrease of photosystems i and ii in a cyanobacterial mutant lacking light-independent protochlorophyllide reductase.	the chll gene encodes one subunit of the light-independent protochlorophyllide reductase. a chll-lacking mutant of the cyanobacterium plectonema boryanum is unable to synthesize chlorophyll (chl) in the dark, causing chl synthesis to become light-dependent as in angiosperms. when the mutant cells were cultivated heterotrophically in the dark, chl synthesis was arrested and the chl content decreased exponentially in reverse profile to cell propagation, indicating that most of the pre-existing chl ...	2003	12602881
[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 ...	2003	12698800
[comparative characteristics of native proteinases of the cyanobacteria plectonema boryanum and anabaena variabilis and those induced by cyanophages].	physico-chemical and catalytic properties of proteinases of native and induced cells of cyanobacteria plectonema boryanum have been comparatively studied. it has been established that at early stages of reproduction of cyanophage lpp-3 in cyanobacteria p. boryanum is formed de novo proteinase complex consisting at least of five enzymes. proteinases induced by the virus are distinguished from those of native cells by a series of physico-chemical characteristics and possess higher catalytic activi ...	2003	12945190
[construction of vector plasmids for the plectonema boryanum cyanobacterium and creation, on such basis, of the vector-host system].	the plasmid composition of the plectonema boryanum gom. cyanobacterium, strain calu 465, was analyzed. a small psm1 plasmid, size 1.5, was chosen for genetic engineering. the physical map, constructed for the plasmid, was used to create the psts series, i.e. vector construction for the p. boryanum cyanobacterium. a method was selected and tested for the introduction of the vector into host cells. the needed orientation of psm1 cyanobacterium plasmid within the vector as well as a possible role o ...	2003	12966925
[localization of dnaase activity in cyanobacterium plectonema boryanum calu 465].	it was shown in experiments carried out on cyanobacterium p. boryanum, that when cells are incubated in a buffer with low concentrations of nonion detergent (0.1%, triton x-100) one can observe the dnase activity release into the medium. the methods of supersound desintegration of cells and following gradient centrifugation of the cell-free extracts were used to obtain three fractions of the cell membranes identified by means of spectrophotometric analysis. it has been established that p. boryan ...	2003	15077546
[construction of shuttle expression vector and expression of thymosin alpha 1 in synechococcus sp. pcc7942].	the shutter expression vector ppreut was constructed from the plasmid pprs-1 containing the endogenous small plasmid of plectonema boryanum. the expression elements such as heat shock gene groesl promoter, foreign gene ub-thymosin alpha 1, rbcs polya terminator and kanamycin resistance gene were all included. the shutter plasmid ppreut was directly transferred into synechococcus sp. pcc7942. the transformants were obtained through kanamycin screening. southern blotting analysis showed that the s ...	2003	12751202
an alternate photosynthetic electron donor system for psi supports light dependent nitrogen fixation in a non-heterocystous cyanobacterium, plectonema boryanum.	plectonema boryanum exhibits temporal separation of photosynthesis and nitrogen fixation under diazotrophic conditions. during nitrogen fixation, the photosynthetic electron transport chain becomes impaired, which leads to the uncoupling of the psii and psi activities. a 30-40% increase in psi activity and continuous generation of atp through light-dependent processes seem to support the nitrogen fixation. the use of an artificial electron carrier that shuttles electrons between the plastoquinon ...	2003	12685043
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 ...	2004	15066804
[isolation and purification of nonspecific nuclease of cyanobacterium plectonema boryanum calu 465].	nonspecific nuclease has been isolated from the cells of cyanobacterium plectonema boryanum and purified to homogenic state. it has been established that the method of centrifugation of cell-free culture extract in the sucrose density gradient is efficient for the separation of pigment proteins and enzyme concentration. under the successive use of two ion-exchangers the nuclease activity was determined in the concentration range of nacl 0.065-0.085 m after separation of the cell-free cyanobacter ...	2004	15104052
volatile organic compound (voc) analysis and sources of limonene, cyclohexanone and straight chain aldehydes in axenic cultures of calothrix and plectonema.	the volatile organic compounds (vocs) in four standing cultures of axenic benthic cyanobacteria (calothrix and plectonema) were studied by gc/ms analysis. to verify the biogenic origin of the vocs, 13c-labelling experiments were performed, and the differences in labelling were used to differentiate between biogenic and non-biogenic sources. strongly labelled biogenic compounds were derived from the shikimate (cresol, skatole), isoprenoid (beta-cyclocitral, beta-ionone, geosmin) and fatty acid pa ...	2004	15237606
microbial diversity of extant stromatolites in the hypersaline marine environment of shark bay, australia.	stromatolites have been present on earth, at various levels of distribution and diversity, for more than 3 billion years. today, the best examples of stromatolites forming in hypersaline marine environments are in hamelin pool at shark bay, western australia. despite their evolutionary significance, little is known about their associated microbial communities. using a polyphasic approach of culture-dependent and culture-independent methods, we report the discovery of a wide range of microorganis ...	2004	15344935
[the nucleotide sequence of the rep gene of cyanobacterial plasmid psm1].	the nucleotide sequence was established for the rep gene of plasmid psm1 isolated from cyanobacterium plectonema boryanum calu 465. both nucleotide sequence and the encoded amino acid sequences showed 98% homology to the corresponding sequences of small plasmids ppf1, pgl3, ppbs1, pblx, and ppb1. an active center was identified in the replicative protein sequences.	2004	15458212
[psts4--a new shuttle vector for cyanobacterium plectonema boryanum calu 465].	three vector constructions--psts2, psts3 and psts4 have been obtained on the basis of the standard vector for escherichia coli pbr 322, cyanobacterial plasmid psm1 and its separate fragments. the structure of psts4, carrying the full-size plasmid psm1 (cloned by the restriction site hpa ii), replicated both in the cells of e. coli and in the cells-transconjugants of the trichomal cyanobacterium plectonema boryanum. under these conditions resistance of p. boryanum cells to ampicillin increases th ...	2004	15515899
genetic potential for secondary metabolite production in stromatolite communities.	the cyanobacterial communities associated with stromatolites surviving in extreme habitats are a potentially rich source of bioactive secondary metabolites. we screened for the potential for production of bioactive metabolites in diverse species of cyanobacteria isolated from stromatolites in hamelin pool, shark bay, australia. using degenerate primer sets, putative peptide synthetase and polyketide synthase genes were detected from strains of symploca, leptolyngybya, microcoleus, pleuorocapsa, ...	2005	15668032
common freshwater cyanobacteria grow in 100% co2.	cyanobacteria and similar organisms produced most of the oxygen found in earth's atmosphere, which implies that early photosynthetic organisms would have lived in an atmosphere that was rich in co2 and poor in o2. we investigated the tolerance of several cyanobacteria to very high (>20 kpa) concentrations of atmospheric co2. cultures of synechococcus pcc7942, synechocystis pcc7942, plectonema boryanum, and anabaena sp. were grown in liquid culture sparged with co2-enriched air. all four strains ...	2005	15711170
solenoids and plectonemes in stretched and twisted elastomeric filaments.	we study the behavior of a naturally straight highly extensible elastic filament subjected to large extensional and twisting strains. we find that two different phases can coexist for a range of parameter values: the plectoneme and the solenoid. a simple theory based on a neo-hookean model for the material of the filament and accounting for the slender geometry suffices to explain these observations, and leads to a phase diagram that is consistent with observations. extension and relaxation expe ...	2005	16090920
growth, photosynthesis, active oxygen species and antioxidants responses of paddy field cyanobacterium plectonema boryanum to endosulfan stress.	the present paper deals with the insecticide endosulfan (5, 10 and 20 microg/ml)-induced changes in physiological and biochemical parameters related to photosynthesis and defense systems in paddy field cyanobacterium plectonema boryanum grown under laboratory conditions. growth and photosynthetic pigments, i.e., chlorophyll a, carotenoids and phycocyanin, were adversely affected by endosulfan treatment and the inhibition was found to be dose dependent. the toxic effect of endosulfan was more pro ...	2005	15942872
differential operation of dual protochlorophyllide reductases for chlorophyll biosynthesis in response to environmental oxygen levels in the cyanobacterium leptolyngbya boryana.	most oxygenic phototrophs, including cyanobacteria, have two structurally unrelated protochlorophyllide (pchlide) reductases in the penultimate step of chlorophyll biosynthesis. one is light-dependent pchlide reductase (lpor) and the other is dark-operative pchlide reductase (dpor), a nitrogenase-like enzyme assumed to be sensitive to oxygen. very few studies have been conducted on how oxygen-sensitive dpor operates in oxygenic phototrophic cells. here, we report that anaerobic conditions are re ...	2006	17028153
mechanisms of gold bioaccumulation by filamentous cyanobacteria from gold(iii)-chloride complex.	the mechanisms of gold bioaccumulation by cyanobacteria (plectonema boryanum utex 485) from gold(iii)-chloride solutions have been studied at three gold concentrations (0.8,1.7, and 7.6 mm) at 25 degrees c, using both fixed-time laboratory and real-time synchrotron radiation absorption spectroscopy (xas) experiments. interaction of cyanobacteria with aqueous gold(iii)-chloride initially promoted the precipitation of nanoparticles of amorphous gold(i)-sulfide at the cell walls, and finally deposi ...	2006	17120557
synthesis of platinum nanoparticles by reaction of filamentous cyanobacteria with platinum(iv)-chloride complex.	interaction of cyanobacteria (plectonema boryanum utex 485) with aqueous platinum(iv)-chloride (ptcl(4) degrees ) has been investigated at 25-100 degrees c for up to 28 days, and 180 degrees c for 1 day. the addition of ptcl(4) degrees to the cyanobacteria culture initially promoted the precipitation of pt(ii)-organic material as amorphous spherical nanoparticles (< or =0.3 microm) in solutions and dispersed nanoparticles within bacterial cells. the spherical pt(ii)-organic nanoparticles were co ...	2006	16893232
morphology of gold nanoparticles synthesized by filamentous cyanobacteria from gold(i)-thiosulfate and gold(iii)--chloride complexes.	plectonema boryanum utex 485, a filamentous cyanobacterium, has been reacted with aqueous au(s(2)o(3))(2)(3)(-) and aucl(4)(-) solutions ( approximately 400-550 mg/l au) at 25-100 degrees c for up to 1 month and at 200 degrees c for 1 day. the interaction of cyanobacteria with aqueous au(s(2)o(3))(2)(3)(-) promoted the precipitation of cubic (100) gold nanoparticles (<10-25 nm) at membrane vesicles and admixed with gold sulfide within cells and encrusted on the cyanobacteria, whereas reaction wi ...	2006	16519482
biosynthesis of silver nanoparticles by filamentous cyanobacteria from a silver(i) nitrate complex.	the biosynthesis of silver nanoparticles has been successfully conducted using plectonema boryanum utex 485, a filamentous cyanobacterium, reacted with aqueous agno3 solutions (approximately 560 mg/l ag) at 25-100 degrees c for up to 28 days. the interaction of cyanobacteria with aqueous agno3 promoted the precipitation of spherical silver nanoparticles and octahedral (111) silver platelets (of up to 200 nm) in solutions. the mechanisms of silver nanoparticles via cyanobacteria could involve met ...	2007	17309217
the geomicrobiology of gold.	microorganisms capable of actively solubilizing and precipitating gold appear to play a larger role in the biogeochemical cycling of gold than previously believed. recent research suggests that bacteria and archaea are involved in every step of the biogeochemical cycle of gold, from the formation of primary mineralization in hydrothermal and deep subsurface systems to its solubilization, dispersion and re-concentration as secondary gold under surface conditions. enzymatically catalysed precipita ...	2007	18043665
synthesis of palladium nanoparticles by reaction of filamentous cyanobacterial biomass with a palladium(ii) chloride complex.	the interaction of cyanobacterial biomass (plectonema boryanum utex 485) with aqueous palladium(ii) chloride (pdcl2 degrees ) has been investigated at 25-100 degrees c for up to 28 days. we report that the release of organic materials from the cyanobacteria promoted the precipitation of pd(0) as crystalline spherical and elongate nanoparticles (< or =30 nm), both in solution and as dispersed and encrusted nanoparticles on cyanobacterial cells. in contrast, under abiotic conditions at 100 degrees ...	2007	17658865
dissolution of dead corals by euendolithic microorganisms across the northern great barrier reef (australia).	spatial and temporal variabilities in species composition, abundance, distribution, and bioeroding activity of euendolithic microorganisms were investigated in experimental blocks of the massive coral porites along an inshore-offshore transect across the northern great barrier reef (australia) over a 3-year period. inshore reefs showed turbid and eutrophic waters, whereas the offshore reefs were characterized by oligotrophic waters. the euendolithic microorganisms and their ecological characteri ...	2008	17690835
chromatin fiber structure and plectonemic model of chromosome condensation in drosophila cells.	reversible permeable cells have been used to isolate chromatin structures during the process of chromosome condensation. analysis of individual structures slipping out from nuclei after reversal of permeabilization revealed that chromosomes of drosophila cells consist of small units called rodlets. the fluorescent images of chromatin fibers were subjected to computer analysis allowing the computer-aided visualization of chromatin fibers. the zig-zag array of fibers consisting of 12-15 nucleosome ...	2008	18171101
oxygen sensitivity of a nitrogenase-like protochlorophyllide reductase from the cyanobacterium leptolyngbya boryana.	dark-operative protochlorophyllide (pchlide) oxido-reductase (dpor) is a nitrogenase-like enzyme that catalyzes pchlide reduction, the penultimate step of chlorophyll a biosynthesis. dpor is distributed widely among oxygenic phototrophs such as cyanobacteria, green algae and gymnosperms. to determine how dpor operates in oxygenic photosynthetic cells, we constructed two shuttle vectors for overexpression of strep-tagged l-protein (chll) and strep-tagged nb-protein (chln-chlb) in leptolyngbya bor ...	2009	19643808
nitrate assimilatory genes and their transcriptional regulation in a unicellular red alga cyanidioschyzon merolae: genetic evidence for nitrite reduction by a sulfite reductase-like enzyme.	cyanidioschyzon merolae is a unicellular red alga living in acid hot springs, which is able to grow on ammonium, as well as nitrate as sole nitrogen source. based on the complete genome sequence, proteins for nitrate utilization, nitrate transporter (nrt) and nitrate reductase (nr), were predicted to be encoded by the neighboring nuclear genes cmg018c and cmg019c, respectively, but no typical nitrite reductase (nir) gene was found by similarity searches. on the other hand, two candidate genes fo ...	2010	20375110
hydrogen generation through indirect biophotolysis in batch cultures of the nonheterocystous nitrogen-fixing cyanobacterium plectonema boryanum.	the nitrogen-fixing nonheterocystous cyanobacterium plectonema boryanum was used as a model organism to study hydrogen generation by indirect biophotolysis in nitrogen-limited batch cultures that were continuously illuminated and sparged with argon/co(2) to maintain anaerobiosis. the highest hydrogen-production rate (i.e., 0.18 ml/mg day or 7.3 micromol/mg day) was observed in cultures with an initial medium nitrate concentration of 1 mm at a light intensity of 100 micromol/m(2) s. the addition ...	2010	19697159
Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.	Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30-ádays. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirm ...	2011	21732035