| fra proteins influencing filament integrity, diazotrophy and localization of septal protein sepj in the heterocyst-forming cyanobacterium anabaena sp. | anabaena sp. strain pcc 7120 is a filamentous cyanobacterium that can fix n(2) in differentiated cells called heterocysts, which exchange nutritional and regulatory compounds with the neighbouring photosynthetic vegetative cells. the cells in the filament appear to be joined by some protein structures, of which sepj (frag) that is located at the cell poles in the intercellular septa and is needed for filament integrity seems to be a component. other known proteins required for filament integrity ... | 2010 | 20487302 |
| biogeochemical cycling and microbial diversity in the thrombolitic microbialites of highborne cay, bahamas. | thrombolites are unlaminated carbonate build-ups that are formed via the metabolic activities of complex microbial mat communities. the thrombolitic mats of highborne cay, bahamas develop in close proximity (1-2 m) to accreting laminated stromatolites, providing an ideal opportunity for biogeochemical and molecular comparisons of these two distinctive microbialite ecosystems. in this study, we provide the first comprehensive characterization of the biogeochemical activities and microbial diversi ... | 2010 | 20491947 |
| multiple origins of high reciprocal symbiotic specificity at an intercontinental spatial scale among gelatinous lichens (collemataceae, lecanoromycetes). | because the number of fungal species (mycobionts) exceeds the number of algae and cyanobacteria (photobionts) found in lichens by more than two orders of magnitude, reciprocal one-to-one specificity between one fungal species and one photobiont across their entire distribution is not expected in this symbiotic system, and has not previously been observed. the specificity of the cyanobacterium nostoc found in lichens was evaluated at a broad geographical scale within one of the main families of l ... | 2010 | 20493269 |
| a novel role for a tonb-family protein and photoregulation of iron acclimation in fremyella diplosiphon. | photosynthetic organisms display adaptations to changes in light and nutrient availability. iron, which is required for the function of photosynthetic photosystems and other important biochemical processes, is an essential mineral that consequently impacts not only overall photosynthetic efficiency, but also the physiology of organisms in general. our recent study represents the first functional characterization of a cyanobacterial tonb protein. tonb proteins classically are membrane proteins th ... | 2010 | 20495348 |
| a new chlorophyll d-containing cyanobacterium: evidence for niche adaptation in the genus acaryochloris. | chlorophyll d is a photosynthetic pigment that, based on chemical analyses, has only recently been recognized to be widespread in oceanic and lacustrine environments. however, the diversity of organisms harbouring this pigment is not known. until now, the unicellular cyanobacterium acaryochloris marina is the only characterized organism that uses chlorophyll d as a major photopigment. in this study we describe a new cyanobacterium possessing a high amount of chlorophyll d, which was isolated fro ... | 2010 | 20505751 |
| microvirin, a novel alpha(1,2)-mannose-specific lectin isolated from microcystis aeruginosa, has anti-hiv-1 activity comparable with that of cyanovirin-n but a much higher safety profile. | microvirin (mvn), a recently isolated lectin from the cyanobacterium microcystis aeruginosa pcc7806, shares 33% identity with the potent anti-human immunodeficiency virus (hiv) protein cyanovirin-n (cv-n) isolated from nostoc ellipsosporum, and both lectins bind to similar carbohydrate structures. mvn is able to inhibit infection by a wide variety of hiv-1 laboratory-adapted strains and clinical isolates of different tropisms and subtypes in peripheral blood mononuclear cells. mvn also inhibits ... | 2010 | 20507987 |
| treatment of cr(vi)-containing wastewaters with exopolysaccharide-producing cyanobacteria in pilot flow through and batch systems. | seven exopolysaccharide-producing cyanobacteria were tested with regard to their capability to remove cr(vi) from the wastewater of a plating industry. the cyanobacterium which showed, under lab conditions, the most promising features with regard to both cr(vi) removal (about 12 mg of cr(vi) removed per gram of dry biomass) and growth characteristics (highest growth rate and simplest culture medium) was nostoc pcc7936. furthermore, in lab experiments, it was also found that a hcl pretreatment is ... | 2010 | 20508931 |
| role of multiple hlr1 sequences in the regulation of the dual promoters of the psaab genes in synechocystis sp. pcc 6803. | previously, we analyzed the promoter architecture of the psaab genes encoding reaction center subunits of photosystem i (psi) in the cyanobacterium synechocystis sp. pcc 6803. there exist two promoters, p1 and p2, both of which show typical high-light (hl) response of psi genes; their activities are high under low-light (ll) conditions but rapidly downregulated upon the shift to hl conditions. in this study, it was suggested that a response regulator rpab binds to multiple high-light regulatory ... | 2010 | 20511509 |
| spheroid bodies in rhopalodiacean diatoms were derived from a single endosymbiotic cyanobacterium. | members of the diatom family rhopalodiaceae possess cyanobacteria-derived intracellular structures called spheroid bodies (sbs) that very likely carry out nitrogen fixation. due to the shortage of molecular data from sbs and rhopalodiacean diatoms, it remains unclear how sbs were established and spread in rhopalodiacean diatoms. we here amplified the small subunit ribosomal dna sequences from both host and sb in three rhopalodiacean diatom species, epithemia turgida, e. sorex, and rhopalodia gib ... | 2011 | 20512519 |
| evolved diversification of a modular natural product pathway: apratoxins f and g, two cytotoxic cyclic depsipeptides from a palmyra collection of lyngbya bouillonii. | a collection of lyngbya bouillonii from palmyra atoll in the central pacific, a site several thousand kilometers distant from all previous collections of this chemically prolific species of cyanobacterium, was found to contain two new cancer cell cytotoxins of the apratoxin family. the structures of the new compounds, apratoxins f and g, were determined by 1d and 2d nmr techniques in combination with mass spectrometric methods. stereochemistry was explored by using chromatographic analyses of th ... | 2010 | 20512792 |
| evolution and function of the plant cell wall synthesis-related glycosyltransferase family 8. | carbohydrate-active enzyme glycosyltransferase family 8 (gt8) includes the plant galacturonosyltransferase1-related gene family of proven and putative alpha-galacturonosyltransferase (gaut) and gaut-like (gatl) genes. we computationally identified and investigated this family in 15 fully sequenced plant and green algal genomes and in the national center for biotechnology information nonredundant protein database to determine the phylogenetic relatedness of the gauts and gatls to other gt8 family ... | 2010 | 20522722 |
| inorganic carbon acquisition by eukaryotic algae: four current questions. | the phylogenetically and morphologically diverse eukaryotic algae are typically oxygenic photolithotrophs. they have a diversity of incompletely understood mechanisms of inorganic carbon acquisition: this article reviews four areas where investigations continue. the first topic is diffusive co(2) entry. most eukaryotic algae, like all cyanobacteria, have inorganic carbon concentrating mechanisms (ccms). the ancestral condition was presumably the absence of a ccm, i.e. diffusive co(2) entry, as f ... | 2010 | 20524069 |
| characterization of manganese superoxide dismutase from a marine cyanobacterium leptolyngbya valderiana bdu20041. | abstract: | 2010 | 20525290 |
| the network of p(ii) signalling protein interactions in unicellular cyanobacteria. | p(ii) signalling proteins constitute a large superfamily of signal perception and transduction proteins, which is represented in all domains of life and whose members play central roles in coordinating nitrogen assimilation. generally, p(ii) proteins act as sensors of the cellular adenylylate energy charge and 2-oxoglutarate level, and in response to these signals, they regulate central nitrogen assimilatory processes at various levels of control (from nutrient transport to gene expression) thro ... | 2010 | 20532736 |
| multicellularity in a heterocyst-forming cyanobacterium: pathways for intercellular communication. | the filamentous, heterocyst-forming cyanobacteria are among the simplest multicellular prokaryotes, and anabaena sp. strain pcc 7120 is being used as a model for studying multicellularity in these organisms. in the absence of combined nitrogen two interdependent cell types are present in an anabaena filament: vegetative cells and heterocysts. vegetative cells perform oxygenic photosynthesis and supply carbon compounds to the heterocysts, which are specialized in the assimilation of atmospheric n ... | 2010 | 20532739 |
| phycobiliprotein biosynthesis in cyanobacteria: structure and function of enzymes involved in post-translational modification. | cyanobacterial phycobiliproteins are brilliantly colored due to the presence of covalently attached chromophores called bilins, linear tetrapyrroles derived from heme. for most phycobiliproteins, these post-translational modifications are catalyzed by enzymes called bilin lyases; these enzymes ensure that the appropriate bilins are attached to the correct cysteine residues with the proper stereochemistry on each phycobiliprotein subunit. phycobiliproteins also contain a unique, post-translationa ... | 2010 | 20532743 |
| better living through cyanothece - unicellular diazotrophic cyanobacteria with highly versatile metabolic systems. | cyanothece sp. atcc 51142 is a unicellular, diazotrophic cyanobacterium with a versatile metabolism and very pronounced diurnal rhythms. since nitrogen fixation is exquisitely sensitive to oxygen, cyanotheceutilizes temporal regulation to accommodate these incompatible processes in a single cell. when grown under 12 h light-dark (ld) periods, it performs photosynthesis during the day and n(2) fixation and respiration at night. genome sequences of cyanothece sp. atcc 51142 and that of five other ... | 2010 | 20532747 |
| synergistic allelochemicals from a freshwater cyanobacterium. | the ability of cyanobacteria to produce complex secondary metabolites with potent biological activities has gathered considerable attention due to their potential therapeutic and agrochemical applications. however, the precise physiological or ecological roles played by a majority of these metabolites have remained elusive. several studies have shown that cyanobacteria are able to interfere with other organisms in their communities through the release of compounds into the surrounding medium, a ... | 2010 | 20534563 |
| cccs and cccp are involved in construction of cell surface components in the cyanobacterium synechocystis sp. strain pcc 6803. | we have previously identified two target genes (slr1667 and slr1668) for transcriptional regulation by a camp receptor protein, sycrp1, in a camp-dependent manner. for this study we investigated the localizations of products of slr1667 and slr1668 (designated cccs and cccp, respectively) biochemically and immunocytochemically, and examined the phenotypes of their disruptants. cccs protein was detected in the culture medium and the acid-soluble fraction containing proteins derived from outside th ... | 2010 | 20538620 |
| did trypanosomatid parasites contain a eukaryotic alga-derived plastid in their evolutionary past? | the trypanosomatidae is closely related to euglenids that harbor plastids acquired from a green alga via secondary endosymbiosis. this discovery led to the idea that trypanosomatid parasites contained a green alga-derived plastid in their evolutionary past, an evolutionary scenario that was criticized based on the rarity of plant/plastid/cyanobacterium-like genes in the completely sequenced genomes of trypanosoma and leishmania species. because it is difficult to identify such genes, however, th ... | 2010 | 20540605 |
| redirecting reductant flux into hydrogen production via metabolic engineering of fermentative carbon metabolism in a cyanobacterium. | some aquatic microbial oxygenic photoautotrophs (amops) make hydrogen (h(2)), a carbon-neutral, renewable product derived from water, in low yields during autofermentation (anaerobic metabolism) of intracellular carbohydrates previously stored during aerobic photosynthesis. we have constructed a mutant (the ldha mutant) of the cyanobacterium synechococcus sp. strain pcc 7002 lacking the enzyme for the nadh-dependent reduction of pyruvate to d-lactate, the major fermentative reductant sink in thi ... | 2010 | 20543051 |
| mechanisms used for genomic proliferation by thermophilic group ii introns. | mobile group ii introns, which are found in bacterial and organellar genomes, are site-specific retroelements hypothesized to be evolutionary ancestors of spliceosomal introns and retrotransposons in higher organisms. most bacteria, however, contain no more than one or a few group ii introns, making it unclear how introns could have proliferated to higher copy numbers in eukaryotic genomes. an exception is the thermophilic cyanobacterium thermosynechococcus elongatus, which contains 28 closely r ... | 2010 | 20543989 |
| light-induced changes within photosystem ii protects microcoleus sp. in biological desert sand crusts against excess light. | the filamentous cyanobacterium microcoleus vaginatus, a major primary producer in desert biological sand crusts, is exposed to frequent hydration (by early morning dew) followed by desiccation during potentially damaging excess light conditions. nevertheless, its photosynthetic machinery is hardly affected by high light, unlike "model" organisms whereby light-induced oxidative stress leads to photoinactivation of the oxygen-evolving photosystem ii (psii). field experiments showed a dramatic decl ... | 2010 | 20544016 |
| the cyabrb transcription factor cala regulates the iron superoxide dismutase in nostoc sp. strain pcc 7120. | in the present investigation the results of induced over-production of the cyabrb transcription factor cala (cyanobacterial abrb-like, annotated as alr0946) in the cyanobacterium nostoc sp. pcc 7120 were analysed. the cala overexpression strain showed a bleaching phenotype with lower growth rate and truncated filaments 2 days after induction of overexpression. the phenotype was even more pronounced when illumination was increased from 35 to 125 µmol m(-2) s(-1). using gel-based quantitative prot ... | 2010 | 20545738 |
| ectopic expression of hetp can partially bypass the need for hetr in heterocyst differentiation by anabaena sp. strain pcc 7120. | differentiation of nitrogen-fixing cells, called heterocysts, by the cyanobacterium anabaena sp. strain pcc 7120 requires hetr, which is considered the master regulator of heterocyst differentiation. in this study, ectopic expression of hetp from an inducible promoter was shown to partially bypass the need for hetr in heterocyst differentiation. a hetr-deletion strain with hetp expressed ectopically produced cells morphologically similar to heterocysts that produced exopolysaccharide and glycoli ... | 2010 | 20545862 |
| a new player in the regulatory cascade controlling heterocyst differentiation in cyanobacteria. | heterocysts are terminally differentiated cells that fix nitrogen in filaments of the cyanobacterium anabaena pcc 7120. they differentiate from vegetative cells at regular intervals along each filament. the developmental process is initiated by an increase in the ratio of reduced carbon to reduced nitrogen. this cue triggers protein ntca to activate transcription of nrra, which leads to transcription of the hetr gene. hetr is a master transcription factor required for expression of many heterocy ... | 2010 | 20545863 |
| structure of the novel 14kda fragment of alpha-subunit of phycoerythrin from the starving cyanobacterium phormidium tenue. | the rod-like phycobilisome (pbs) in cyanobacterium is the light-harvesting complex of phycoerythrin (pe), phycocyanin (pc) and allophycocyanin (apc). the orderly degradation of pbs was observed under starvation conditions. a 14 kda truncated fragment of alpha-subunit of pe (f-alphape) was identified from the degraded product. f-alphape was purified to homogeneity, sequenced and crystallized. the merohedrally twinned crystals with a twinning factor of approximately 0.5 were obtained. the crystal ... | 2010 | 20546902 |
| bentazon triggers the promotion of oxidative damage in the portuguese ricefield cyanobacterium anabaena cylindrica: response of the antioxidant system. | rice fields are frequently exposed to environmental contamination by herbicides and cyanobacteria, as primary producers of these aquatic ecosystems, are adversely affected. anabaena cylindrica is a cyanobacterium with a significantly widespread occurrence in portuguese rice fields. this strain was studied throughout 72 h in laboratory conditions for its stress responses to sublethal concentrations (0.75-2 mm) of bentazon, a selective postemergence herbicide recommended for integrated weed manage ... | 2010 | 20549627 |
| in vivo studies on the immunotoxic effects of microcystins on rabbit. | microcystins (mcs) are the toxic molecules produced by common cyanobacterium in freshwater blooms. their toxicities raise severe health issues in livestock and human beings. in current study, the immunotoxic effects of mc-lr were investigated in rabbit through evaluating the dynamics of white blood cell (wbc) numbers and cytokine production such as interleukin-3 (il-3), il-4, il-6, interferon-gamma (ifn-gamma), tumor necrosis factor-alpha (tnf-alpha). mcs at the high dose (50 mug mc-lreq kg(-1)) ... | 2010 | 20549643 |
| methyladeninylcobamide functions as the cofactor of methionine synthase in a cyanobacterium, spirulina platensis nies-39. | to clarify the physiological function of pseudovitamin b(12) (or adeninylcobamide; adecba) in spirulina platensis nies-39, cobalamin-dependent methionine synthase (ms) was characterized. we cloned the full-length spirulina ms. the clone contained an open reading frame encoding a protein of 1183 amino acids with a molecular mass of 132 kda. deduced amino acid sequences of the spirulina ms contained critical residues identical to cobalamin-, zinc-, s-adenosylmethionine-, and homocysteine-binding m ... | 2010 | 20558164 |
| crystal structure of the nitrogenase-like dark operative protochlorophyllide oxidoreductase catalytic complex (chln/chlb)2. | during (bacterio)chlorophyll biosynthesis of many photosynthetically active organisms, dark operative protochlorophyllide oxidoreductase (dpor) catalyzes the two-electron reduction of ring d of protochlorophyllide to form chlorophyllide. dpor is composed of the subunits chll, chln, and chlb. homodimeric chll(2) bearing an intersubunit [4fe-4s] cluster is an atp-dependent reductase transferring single electrons to the heterotetrameric (chln/chlb)(2) complex. the latter contains two intersubunit [ ... | 2010 | 20558746 |
| cyanide in bronchoalveolar lavage is not diagnostic for pseudomonas aeruginosa in children with cystic fibrosis. | early detection of the cyanobacterium pseudomonas aeruginosa in the lungs of young children with cystic fibrosis (cf) is considered the key to delaying chronic pulmonary disease. we investigated whether cyanide in bronchoalveolar lavage (bal) fluid could be used as an early diagnostic biomarker of infection. cyanide was measured in 226 bal samples (36 p. aeruginosa infected) obtained from 96 infants and young children with cf participating in an early surveillance programme involving annual bal. ... | 2011 | 20562125 |
| direct and rapid pcr amplification using digested tissues for the diagnosis of drowning. | we developed a direct and rapid method for the diagnosis of death by drowning by pcr amplification of phytoplankton dna using human tissues. the primers were designed based on the dna sequence of the 16s ribosomal rna gene (16s rdna) of cyanobacterium. samples of lung, liver and kidney tissues were collected from 53 autopsied individuals diagnosed as death by drowning. without dna extraction, the tissue fragments were incubated directly in a digest buffer developed in this study, for 20 min. usi ... | 2010 | 20564264 |
| detection of reactive oxygen species (ros) by the oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate in the cyanobacterium anabaena variabilis pcc 7937. | the generation of reactive oxygen species (ros) under simulated solar radiation (uv-b: 0.30wm(-2), uv-a: 25.70wm(-2) and par: 118.06wm(-2)) was studied in the cyanobacterium anabaena variabilis pcc 7937 using the oxidant-sensing fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (dcfh-da). dcfh-da is a nonpolar dye, converted into the polar derivative dcfh by cellular esterases that are nonfluorescent but switched to highly fluorescent dcf when oxidized by intracellular ros and other p ... | 2010 | 20570649 |
| is nostoc h-nox a no sensor or redox switch? | nostoc sp. (ns) h-nox is a heme protein found in symbiotic cyanobacteria, which has approximately 35% sequence identity and high structural homology to the beta subunit of soluble guanylyl cyclase (sgc), suggesting a no sensing function. however, uv-vis, epr, nir mcd, and ligand binding experiments with ferrous and ferric ns h-nox indicate significant functional differences between ns h-nox and sgc. (1) after no binding to sgc, the proximal histidine dissociates from the heme iron, causing a con ... | 2010 | 20572679 |
| [expression, purification and activity determination of cyanovirin-n]. | cyanovirin-n (cvn) is an 11 kda anti-hiv protein originally isolated from extracts of a cyanobacterium, nostoc ellipsosporum. the protein binds with high affinity to the viral envelope glycoprotein gp120 and irreversibly inactivates diverse hiv strains. a fusion gene consisting of cvn, sumo and 6xhis tag was synthesized by pcr according to the codon bias of escherichia coli. the fusion protein is expressed in the cytoplasm of e. coli in a soluble form and up to 28% of the total protein. the reco ... | 2010 | 20575444 |
| phylogenetic and biochemical evidence supports the recruitment of an adp-glucose translocator for the export of photosynthate during plastid endosymbiosis. | the acquisition of photosynthesis by eukaryotic cells through enslavement of a cyanobacterium represents one of the most remarkable turning points in the history of life on earth. in addition to endosymbiotic gene transfer, the acquisition of a protein import apparatus and the coordination of gene expression between host and endosymbiont genomes, the establishment of a metabolic connection was crucial for a functional endosymbiosis. it was previously hypothesized that the first metabolic connect ... | 2010 | 20576760 |
| evidence from ftir difference spectroscopy of an extensive network of hydrogen bonds near the oxygen-evolving mn(4)ca cluster of photosystem ii involving d1-glu65, d2-glu312, and d1-glu329. | analyses of the refined x-ray crystallographic structures of photosystem ii (psii) at 2.9-3.5 a have revealed the presence of possible channels for the removal of protons from the catalytic mn(4)ca cluster during the water-splitting reaction. as an initial attempt to verify these channels experimentally, the presence of a network of hydrogen bonds near the mn(4)ca cluster was probed with ftir difference spectroscopy in a spectral region sensitive to the protonation states of carboxylate residues ... | 2010 | 20593803 |
| 18o labeling of chlorophyll d in acaryochloris marina reveals that chlorophyll a and molecular oxygen are precursors. | the cyanobacterium acaryochloris marina was cultured in the presence of either h(2)(18)o or (18)o(2), and the newly synthesized chlorophylls (chl a and chl d) were isolated using high performance liquid chromatography and analyzed by mass spectroscopy. in the presence of h(2)(18)o, newly synthesized chl a and d, both incorporated up to four isotopic (18)o atoms. time course h(2)(18)o labeling experiments showed incorporation of isotopic (18)o atoms originating from h(2)(18)o into chl a, with ove ... | 2010 | 20610399 |
| aeruginazole a, a novel thiazole-containing cyclopeptide from the cyanobacterium microcystis sp. | a novel thiazole-containing cyclic peptide, aeruginazole a (1), was isolated from the cyanobacterium microcystis sp. strain (il-323), which was collected from a water reservoir near kfar-yehoshua, valley of armageddon, israel. the planar structure of aeruginazole a was established using homonuclear and inverse-heteronuclear 2d nmr techniques, as well as high-resolution mass spectrometry. the absolute configuration of the asymmetric centers was determined using marfey's method. aeruginazole a pot ... | 2010 | 20614868 |
| first report of anatoxin-a-producing cyanobacterium aphanizomenon issatschenkoi in northeastern germany. | the neurotoxin anatoxin-a (atx), has been detected in several northeast german lakes during the last two decades, but no atx producers have been identified in german water bodies so far. in 2007 and 2008, we analyzed phytoplankton composition and atx concentration in lake stolpsee (ne germany) in order to identify atx producers. sixty-one aphanizomenon spp. strains were isolated, morphologically and phylogenetically characterized, and tested for atx production potential by liquid chromatography- ... | 2010 | 20615427 |
| structural basis for the allosteric control of the global transcription factor ntca by the nitrogen starvation signal 2-oxoglutarate. | 2-oxogluatarate (2-og), a metabolite of the highly conserved krebs cycle, not only plays a critical role in metabolism, but also constitutes a signaling molecule in a variety of organisms ranging from bacteria to plants and animals. in cyanobacteria, the accumulation of 2-og constitutes the signal of nitrogen starvation and ntca, a global transcription factor, has been proposed as a putative receptor for 2-og. here we present three crystal structures of ntca from the cyanobacterium anabaena: the ... | 2010 | 20616047 |
| transcriptional regulation of the heterocyst patterning gene pata from anabaena sp. strain pcc 7120. | the filamentous cyanobacterium anabaena sp. strain pcc 7120 forms a periodic pattern of nitrogen-fixing heterocysts when grown in the absence of combined nitrogen. pata is necessary for proper patterning of heterocysts along filaments. in this study, apparent transcriptional start points (tsps) were identified at nucleotides -305, -614, and -645 relative to the translational start site (-305, -614, and -645 tsps). transcriptional reporter fusions were used to show that transcription from the -30 ... | 2010 | 20622060 |
| combined effects of co2 and light on the n2-fixing cyanobacterium trichodesmium ims101: a mechanistic view. | the marine diazotrophic cyanobacterium trichodesmium responds to elevated atmospheric co(2) partial pressure (pco(2)) with higher n(2) fixation and growth rates. to unveil the underlying mechanisms, we examined the combined influence of pco(2) (150 and 900 microatm) and light (50 and 200 micromol photons m(-2) s(-1)) on trichodesmium ims101. we expand on a complementary study that demonstrated that while elevated pco(2) enhanced n(2) fixation and growth, oxygen evolution and carbon fixation incr ... | 2010 | 20625002 |
| combined effects of co2 and light on the n2-fixing cyanobacterium trichodesmium ims101: physiological responses. | recent studies on the diazotrophic cyanobacterium trichodesmium erythraeum (ims101) showed that increasing co(2) partial pressure (pco(2)) enhances n(2) fixation and growth. significant uncertainties remain as to the degree of the sensitivity to pco(2), its modification by other environmental factors, and underlying processes causing these responses. to address these questions, we examined the responses of trichodesmium ims101 grown under a matrix of low and high levels of pco(2) (150 and 900 mi ... | 2010 | 20625004 |
| genome erosion in a nitrogen-fixing vertically transmitted endosymbiotic multicellular cyanobacterium. | an ancient cyanobacterial incorporation into a eukaryotic organism led to the evolution of plastids (chloroplasts) and subsequently to the origin of the plant kingdom. the underlying mechanism and the identities of the partners in this monophyletic event remain elusive. | 2010 | 20628610 |
| differences in the interactions between the subunits of photosystem ii dependent on d1 protein variants in the thermophilic cyanobacterium thermosynechococcus elongatus. | the main cofactors involved in the oxygen evolution activity of photosystem ii (psii) are located in two proteins, d1 (psba) and d2 (psbd). in thermosynechococcus elongatus, a thermophilic cyanobacterium, the d1 protein is encoded by either the psba(1) or the psba(3) gene, the expression of which is dependent on environmental conditions. it has been shown that the energetic properties of the psba1-psii and those of the psba3-psii differ significantly (sugiura, m., kato, y., takahashi, r., suzuki ... | 2010 | 20630865 |
| a sequestration feedback determines dynamics and temperature entrainment of the kaiabc circadian clock. | the circadian rhythm of the cyanobacterium synechococcus elongatus is controlled by three proteins, kaia, kaib, and kaic. in a test tube, these proteins form complexes of various stoichiometry and the average phosphorylation level of kaic exhibits robust circadian oscillations in the presence of atp. using mathematical modeling, we were able to reproduce quantitatively the experimentally observed phosphorylation dynamics of the kaiabc clockwork in vitro. we thereby identified a highly non-linear ... | 2010 | 20631683 |
| intramolecular modulation of serine protease inhibitor activity in a marine cyanobacterium with antifeedant properties. | extracts of the floridian marine cyanobacterium lyngbya cf. confervoides were found to deter feeding by reef fish and sea urchins (diadema antillarum). this antifeedant activity may be a reflection of the secondary metabolite content, known to be comprised of many serine protease inhibitors. further chemical and nmr spectroscopic investigation led us to isolate and structurally characterize a new serine protease inhibitor 1 that is formally derived from an intramolecular condensation of largamid ... | 2010 | 20631871 |
| nitrifying bacterial growth inhibition in the presence of algae and cyanobacteria. | nitrifying bacteria, cyanobacteria, and algae are important microorganisms in open pond wastewater treatment systems. nitrification involving the sequential oxidation of ammonia to nitrite and nitrate, mainly due to autotrophic nitrifying bacteria, is essential to biological nitrogen removal in wastewater and global nitrogen cycling. a continuous flow autotrophic bioreactor was initially designed for nitrifying bacterial growth only. in the presence of cyanobacteria and algae, we monitored both ... | 2010 | 20632370 |
| a new tool to detect high viscous exopolymers from microalgae. | microalgae are microorganisms often surrounded by a slime layer made of secreted polymeric substances sometimes including polysaccharides. these polysaccharides, weakly described in the literature, can constitute value-added molecules in several industrial areas. the aim of this article is to show that a new tool, the biofilm ring test®, can be used to detect viscous microalgal exopolymers. two red microalgal strains (rhodella violacea and porphyridium purpureum), one cyanobacterium (arthrospira ... | 2011 | 20635192 |
| roles of xanthophyll carotenoids in protection against photoinhibition and oxidative stress in the cyanobacterium synechococcus sp. strain pcc 7002. | synechococcus sp. strain pcc 7002 is a robust, genetically tractable cyanobacterium that produces six different xanthophyll carotenoids (zeaxanthin, cryptoxanthin, myxoxanthophyll (myxol-2'-fucoside), echinenone, 3'-hydroxyechinenone, and synechoxanthin) and tolerates many environmental stresses, including high light intensities. targeted mutations were introduced to block the branches of the carotenoid biosynthetic pathway leading to specific xanthophylls, and a mutant lacking all xanthophylls ... | 2010 | 20638360 |
| posttranscriptional regulation of glutamine synthetase in the filamentous cyanobacterium anabaena sp. pcc 7120: differential expression between vegetative cells and heterocysts. | genes homologous to those implicated in glutamine synthetase (gs) regulation by protein-protein interaction in the cyanobacterium synechocystis sp. strain pcc 6803 are conserved in several cyanobacterial sequenced genomes. we investigated this gs regulatory mechanism in anabaena sp. strain pcc 7120. in this strain the system operates with only one gs inactivation factor (inactivation factor 7a [if7a]), encoded by open reading frame (orf) asl2329 (gifa). following addition of ammonium, expression ... | 2010 | 20639319 |
| algal photosynthesis as the primary driver for a sustainable development in energy, feed, and food production. | high oil prices and global warming that accompany the use of fossil fuels are an incentive to find alternative forms of energy supply. photosynthetic biofuel production represents one of these since for this, one uses renewable resources. sunlight is used for the conversion of water and co₂ into biomass. two strategies are used in parallel: plant-based production via sugar fermentation into ethanol and biodiesel production through transesterification. both, however, exacerbate other problems, in ... | 2010 | 20640935 |
| the interplay between siderophore secretion and coupled iron and copper transport in the heterocyst-forming cyanobacterium anabaena sp. pcc 7120. | iron uptake is essential for gram-negative bacteria including cyanobacteria. in cyanobacteria, however, the iron demand is higher than in proteobacteria due to the function of iron as a cofactor in photosynthesis and nitrogen fixation, but our understanding of iron uptake by cyanobacteria stands behind the knowledge in proteobacteria. here, two genes involved in this process in the heterocyst-forming cyanobacterium anabaena sp. pcc 7120 were identified. orf all4025 encodes sche, a putative cytop ... | 2010 | 20647000 |
| prevalence of a calcium-based alkaline phosphatase associated with the marine cyanobacterium prochlorococcus and other ocean bacteria. | phosphate plays a key role in regulating primary productivity in several regions of the world's oceans and here dissolved organic phosphate can be an important phosphate source. a key enzyme for utilizing dissolved organic phosphate is alkaline phosphatase and the phoa-type of this enzyme has a zinc cofactor. as the dissolved zinc concentration is low in phosphate depleted environments, this has led to the hypothesis that some phytoplankton may be zinc-p co-limited. recently, it was shown that m ... | 2011 | 20649645 |
| determining the fate of microcystis aeruginosa cells and microcystin toxins following chloramination. | the cyanobacterium microcystis aeruginosa can produce potent toxins known as microcystins. while many studies have focussed on the chlorination of microcystin toxins, little work has been conducted with respect to the chloramination of the microcystins. in addition, no studies have been reported on the effect of chloramination on intact microcystis cells. this study was conducted to determine the fate of m. aeruginosa cells and microcystin toxins following chloramination of a drinking water sour ... | 2010 | 20651451 |
| a method for rapid isolation of total rna of high purity and yield from arthrospira platensis. | arthrospira (spirulina) platensis is widely used as a food supplement and has been an economically important species for centuries. however, the genetic aspect of studies of this particular organism has always been neglected, mainly because of the nonavailability of suitable methods for isolation of nucleic acids and the difficulties faced during further manipulations. although total rna has been isolated using commercially available kits, we present a method optimized to obtain dna-free total r ... | 2010 | 20651857 |
| natural antifoulants from the marine cyanobacterium lyngbya majuscula. | filamentous benthic marine cyanobacteria are a prolific source of structurally unique bioactive secondary metabolites. a total of 12 secondary metabolites, belonging to the mixed polyketide-polypeptide structural class, were isolated from the marine cyanobacterium, lyngbya majuscula, and were tested to determine if they showed activity against barnacle larval settlement. the assays revealed four compounds, dolastatin 16, hantupeptin c, majusculamide a, and isomalyngamide a, that showed moderate ... | 2010 | 20658384 |
| the pedr transcriptional regulator interacts with thioredoxin to connect photosynthesis with gene expression in cyanobacteria. | the redox state of the photosynthetic electron transport chain acts as a critical sensing mechanism by regulating the transcription of key genes involved in the acclimation response to a change in the environment. in the present study we show that the small luxr-type regulator pedr interacts with trx (thioredoxin) to achieve photosynthetic electron-transport-dependent transcriptional regulation in the cyanobacterium synechocystis sp. pcc 6803. trxm, an isoform of trx, was isolated as an interact ... | 2010 | 20662766 |
| targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton. | among eukaryotes, four major phytoplankton lineages are responsible for marine photosynthesis; prymnesiophytes, alveolates, stramenopiles, and prasinophytes. contributions by individual taxa, however, are not well known, and genomes have been analyzed from only the latter two lineages. tiny "picoplanktonic" members of the prymnesiophyte lineage have long been inferred to be ecologically important but remain poorly characterized. here, we examine pico-prymnesiophyte evolutionary history and ecolo ... | 2010 | 20668244 |
| chronic toxicity of a triazole fungicide tebuconazole on the growth and metabolic activities of heterocystous, nitrogen-fixing paddy field cyanobacterium, westiellopsis prolifica janet. | this study explored the chronic and harmful effects of different doses of the triazole fungicide, tebuconazole, on the growth, and metabolic and enzymatic variations in the filamentous paddy field cyanobacterium, westiellopsis prolifica janet. the growth of the cyanobacterium was determined by an estimation of the change in pigment contents. chlorophyll-a, carotenoids and accessory pigments such as phycocyanin, allophycocyanin and phycoerythrin, were shown to decline over a 16-day period by a fa ... | 2010 | 20668408 |
| functional and structural characterization of the 2/2 hemoglobin from synechococcus sp. pcc 7002. | cyanobacterium synechococcus sp. pcc 7002 contains a single gene (glbn) coding for glbn, a protein of the 2/2 hemoglobin lineage. the precise function of glbn is not known, but comparison to similar 2/2 hemoglobins suggests that reversible dioxygen binding is not its main activity. in this report, the results of in vitro and in vivo experiments probing the role of glbn are presented. transcription profiling indicated that glbn is not strongly regulated under any of a large number of growth condi ... | 2010 | 20669934 |
| ultraviolet stress delays chromosome replication in light/dark synchronized cells of the marine cyanobacterium prochlorococcus marinus pcc9511. | the marine cyanobacterium prochlorococcus is very abundant in warm, nutrient-poor oceanic areas. the upper mixed layer of oceans is populated by high light-adapted prochlorococcus ecotypes, which despite their tiny genome (approximately 1.7 mb) seem to have developed efficient strategies to cope with stressful levels of photosynthetically active and ultraviolet (uv) radiation. at a molecular level, little is known yet about how such minimalist microorganisms manage to sustain high growth rates a ... | 2010 | 20670397 |
| catabolic function of compartmentalized alanine dehydrogenase in the heterocyst-forming cyanobacterium anabaena sp. strain pcc 7120. | in the diazotrophic filaments of heterocyst-forming cyanobacteria, an exchange of metabolites takes place between vegetative cells and heterocysts that results in a net transfer of reduced carbon to the heterocysts and of fixed nitrogen to the vegetative cells. open reading frame alr2355 of the genome of anabaena sp. strain pcc 7120 is the ald gene encoding alanine dehydrogenase. a strain carrying a green fluorescent protein (gfp) fusion to the n terminus of ald (ald-n-gfp) showed that the ald g ... | 2010 | 20675483 |
| the genome sequence of the cyanobacterium oscillatoria sp. pcc 6506 reveals several gene clusters responsible for the biosynthesis of toxins and secondary metabolites. | we report a draft sequence of the genome of oscillatoria sp. pcc 6506, a cyanobacterium that produces anatoxin-a and homoanatoxin-a, two neurotoxins, and cylindrospermopsin, a cytotoxin. beside the clusters of genes responsible for the biosynthesis of these toxins, we have found other clusters of genes likely involved in the biosynthesis of not-yet-identified secondary metabolites. | 2010 | 20675499 |
| anti-cyanobacterial activity of moringa oleifera seeds. | filtrates from crushed moringa oleifera seeds were tested for their effects on growth and photosystem ii efficiency of the common bloom-forming cyanobacterium microcystis aeruginosa. m. aeruginosa populations exhibited good growth in controls and treatments with 4- and 8-mg crushed moringa seeds per liter, having similar growth rates of 0.50 (+/-0.01) per day. in exposures of 20- to 160-mg crushed moringa seeds l(-1), growth rates were negative and on average -0.23 (+/-0.05) .day(-1). presumably ... | 2010 | 20676212 |
| integrative analysis of large scale expression profiles reveals core transcriptional response and coordination between multiple cellular processes in a cyanobacterium. | cyanobacteria are the only known prokaryotes capable of oxygenic photosynthesis. they play significant roles in global biogeochemical cycles and carbon sequestration, and have recently been recognized as potential vehicles for production of renewable biofuels. synechocystis sp. pcc 6803 has been extensively used as a model organism for cyanobacterial studies. dna microarray studies in synechocystis have shown varying degrees of transcriptome reprogramming under altered environmental conditions. ... | 2010 | 20678200 |
| the alr2505 (osis) gene from anabaena sp. strain pcc7120 encodes a cysteine desulfurase induced by oxidative stress. | nifs-like cysteine desulfurases are widespread enzymes involved in the mobilization of sulfur from cysteine. the genome of the filamentous diazotrophic cyanobacterium anabaena pcc 7120 contains four open reading frames potentially encoding nifs-like proteins. one of them, alr2505, belongs to the pkn22 operon, which enables anabaena to cope with oxidative stress. the alr2505 protein was purified and found to share all the features characteristic of cysteine desufurases. this is the first nifs-lik ... | 2010 | 20681987 |
| protein import into chloroplasts--how chaperones feature into the game. | chloroplasts originated from an endosymbiotic event, in which an ancestral photosynthetic cyanobacterium was engulfed by a mitochondriate eukaryotic host cell. during evolution, the endosymbiont lost its autonomy by means of a massive transfer of genetic information from the prokaryotic genome to the host nucleus. consequently, the development of protein import machineries became necessary for the relocation of proteins that are now nuclear-encoded and synthesized in the cytosol but destined for ... | 2011 | 20682282 |
| na+-stimulated atpase of alkaliphilic halotolerant cyanobacterium aphanothece halophytica translocates na+ into proteoliposomes via na+ uniport mechanism. | when cells are exposed to high salinity conditions, they develop a mechanism to extrude excess na+ from cells to maintain the cytoplasmic na+ concentration. until now, the atpase involved in na+ transport in cyanobacteria has not been characterized. here, the characterization of atpase and its role in na+ transport of alkaliphilic halotolerant aphanothece halophytica were investigated to understand the survival mechanism of a. halophytica under high salinity conditions. | 2010 | 20691102 |
| reassessment of the toxin profile of cylindrospermopsis raciborskii t3 and function of putative sulfotransferases in synthesis of sulfated and sulfonated psp toxins. | the toxigenic freshwater cyanobacterium cylindrospermopsis raciborskii t3 has been used as a model to study and elucidate the biosynthetic pathway of tetrahydropurine neurotoxins associated with paralytic shellfish poisoning (psp). there are nevertheless several inconsistencies and contradictions in the toxin profile of this strain as published by different research groups, and claimed to include carbamoyl (stx, neo, gtx2/3), decarbamoyl (dcstx), and n-sulfocarbamoyl (c1/2, b1) derivatives. our ... | 2010 | 20692275 |
| boosting autofermentation rates and product yields with sodium stress cycling: application to production of renewable fuels by cyanobacteria. | sodium concentration cycling was examined as a new strategy for redistributing carbon storage products and increasing autofermentative product yields following photosynthetic carbon fixation in the cyanobacterium arthrospira (spirulina) maxima. the salt-tolerant hypercarbonate strain cs-328 was grown in a medium containing 0.24 to 1.24 m sodium, resulting in increased biosynthesis of soluble carbohydrates to up to 50% of the dry weight at 1.24 m sodium. hypoionic stress during dark anaerobic met ... | 2010 | 20693449 |
| new class of algicidal compounds and fungicidal activities derived from a chromene amide of amyris texana. | a chromene amide, n-[2-(2,2-dimethyl-2h-1-benzopyran-6-yl)ethyl]-n,3-dimethylbutanamide, was isolated from the etoac extract of the leaves of amyris texana and found to have moderate antifungal activity against colletotrichum spp. and selective algicidal activity against planktothrix perornata, a cyanobacterium (blue-green alga) that causes musty off-flavor in farm-raised channel catfish (ictalurus punctatus). to improve the selective algicidal activity and provide water solubility, a series of ... | 2010 | 20695429 |
| two cytotoxic stereoisomers of malyngamide c, 8-epi-malyngamide c and 8-o-acetyl-8-epi-malyngamide c, from the marine cyanobacterium lyngbya majuscula. | two epimers of malyngamide c, 8-o-acetyl-8-epi-malyngamide c (1) and 8-epi-malyngamide c (3) have been isolated along with known compounds 6-o-acetylmalyngamide f (5), h (6), j (7) k (8), and characterized from a grenada field collection of the marine cyanobacterium lyngbya majuscula. the structures of these compounds were deduced by 1d and 2d nmr spectroscopic and mass spectral data interpretation. absolute configurations were determined by a combination of cd-spectroscopy, chemical degradation ... | 2010 | 20701935 |
| cytotoxic halogenated macrolides and modified peptides from the apratoxin-producing marine cyanobacterium lyngbya bouillonii from guam. | collections of the marine cyanobacterium lyngbya bouillonii from shallow patch reefs in apra harbor, guam, afforded three hitherto undescribed analogues of the glycosidic macrolide lyngbyaloside, namely, 2-epi-lyngbyaloside (1) and the regioisomeric 18e- and 18z-lyngbyalosides c (2 and 3). concurrently we discovered two new analogues of the cytoskeletal actin-disrupting lyngbyabellins, 27-deoxylyngbyabellin a (4) and lyngbyabellin j (5), a novel macrolide of the laingolide family, laingolide b ( ... | 2010 | 20704304 |
| crystal structure of the cyanobacterial signal transduction protein pii in complex with pipx. | p(ii) proteins are highly conserved signal transducers in bacteria, archaea, and plants. they have a large flexible loop (t-loop) that adopts different conformations after covalent modification or binding to different effectors to regulate the functions of diverse protein partners. the p(ii) partner pipx (p(ii)interaction protein x), first identified from synechococcus sp. pcc 7942, exists uniquely in cyanobacteria. pipx also interacts with the cyanobacterial global nitrogen regulator ntca. the ... | 2010 | 20708625 |
| hydrogen cycling by the unicellular marine diazotroph crocosphaera watsonii strain wh8501. | the hydrogen (h₂) cycle associated with the dinitrogen (n₂) fixation process was studied in laboratory cultures of the marine cyanobacterium crocosphaera watsonii. the rates of h₂ production and acetylene (c₂h₂) reduction were continuously measured over the diel cycle with simultaneous measurements of fast repetition rate fluorometry and dissolved oxygen. the maximum rate of h₂ production was coincident with the maximum rates of c₂h₂ reduction. theoretical stoichiometry for n₂ fixation predicts ... | 2010 | 20709832 |
| polyphasic characterization of a thermotolerant siderophilic filamentous cyanobacterium that produces intracellular iron deposits. | despite the high potential for oxidative stress stimulated by reduced iron, contemporary iron-depositing hot springs with circum-neutral ph are intensively populated with cyanobacteria. therefore, studies of the physiology, diversity, and phylogeny of cyanobacteria inhabiting iron-depositing hot springs may provide insights into the contribution of cyanobacteria to iron redox cycling in these environments and new mechanisms of oxidative stress mitigation. in this study the morphology, ultrastruc ... | 2010 | 20709851 |
| color measurements as a reliable method for estimating chlorophyll degradation to phaeopigments. | the application of biocides is a traditional method of controlling biodecay of outdoor cultural heritage. chlorophyll degradation to phaeopigments is used to test the biocidal efficacy of the antimicrobial agents. in the present study, the usefulness of color measurements in estimating chlorophyll degradation was investigated. an aeroterrestrial stone biofilm-forming cyanobacterium of the genus nostoc was chosen as test organism, comparing its different behaviour in both planktonic and biofilm m ... | 2010 | 20714920 |
| structural and functional characterization of a macrophage migration inhibitory factor homologue from the marine cyanobacterium prochlorococcus marinus . | macrophage migration inhibitory factor (mif) is a multifunctional mammalian cytokine, which exhibits tautomerase and oxidoreductase activity. mif homologues with pairwise sequence identities to human mif ranging from 31% to 41% have been detected in various cyanobacteria. the gene encoding the mif homologue from the marine cyanobacterium prochlorococcus marinus strain mit9313 has been cloned and the corresponding protein (pmmif) overproduced, purified, and subjected to functional and structural ... | 2010 | 20715791 |
| the sll0606 protein is required for photosystem ii assembly/stability in the cyanobacterium synechocystis sp. pcc 6803. | an insertional transposon mutation in the sll0606 gene was found to lead to a loss of photoautotrophy but not photoheterotrophy in the cyanobacterium synechocystis sp. pcc 6803. complementation analysis of this mutant (tsll0606) indicated that an intact sll0606 gene could fully restore photoautotrophic growth. gene organization in the vicinity of sll0606 indicates that it is not contained in an operon. no electron transport activity was detected in tsll0606 using water as an electron donor and 2 ... | 2010 | 20724474 |
| functional characterization of a naturally occurring trans-splicing intein from synechococcus elongatus in a mammalian cell system. | we have cloned and characterized a naturally occurring split mini-dnae intein capable of protein trans-splicing in the cyanobacterium synechococcus elongatus (sel dnae intein). sel dnae intein is homologous to synechocystissp. pcc6803 (ssp) dnae intein and nostoc punctiforme (npu) dnae intein, with a protein sequence identity of 60% for the n-terminal part of intein and 61% for the c-terminal part of intein. our results demonstrate that the split reporters, split renilla luciferase (rluc) and en ... | 2010 | 20727340 |
| inactivation of a heterocyst-specific invertase indicates a principal role of sucrose catabolism in heterocysts of anabaena sp. | anabaena sp. strain pcc 7120 is a filamentous cyanobacterium that carries out n(2) fixation in specialized cells called heterocysts, which exchange nutrients and regulators with the filament's vegetative cells that perform the photosynthetic fixation of co(2). the anabaena genome carries two genes coding for alkaline/neutral invertases, inva and invb. as shown by northern analysis, both genes were expressed monocistronically and induced under nitrogen deprivation, although induction was stronger ... | 2010 | 20729363 |
| pulsed nitrogen supply induces dynamic changes in the amino acid composition and microcystin production of the harmful cyanobacterium planktothrix agardhii. | planktothrix agardhii is a widespread harmful cyanobacterium of eutrophic waters, and can produce the hepatotoxins [asp(3)]microcystin-lr and [asp(3)]microcystin-rr. these two microcystin variants differ in their first variable amino acid position, which is occupied by either leucine (l) or arginine (r). although microcystins are extensively investigated, little is known about the mechanisms that determine the production of different microcystin variants. we hypothesize that enhanced nitrogen av ... | 2010 | 20735475 |
| evaluation of methods to extract and quantify lipids from synechocystis pcc 6803. | in order to use the photosynthetic cyanobacterium synechocystis as a source of feedstock for carbon-neutral, nonpetroleum-based diesel fuel, we evaluated several solvents and solvent systems for their ability to extract lipid from wild-type synechocystis pcc 6803. chloroform+methanol-based folch and bligh & dyer methods had the highest lipid recoveries. less toxic solvents, such as methanol and mtbe, or direct trans-esterification of biomass (without pre-extraction step) gave only slightly lower ... | 2011 | 20739178 |
| in situ dynamics of o2, ph and cyanobacterial transcripts associated with ccm, photosynthesis and detoxification of ros. | the relative abundance of transcripts encoding proteins involved in inorganic carbon concentrating mechanisms (ccm), detoxification of reactive oxygen species (ros) and photosynthesis in the thermophilic cyanobacterium synechococcus os-b' was measured in hot spring microbial mats over two diel cycles, and was coupled with in situ determinations of incoming irradiance and microenvironmental dynamics of o(2) and ph. fluctuations in ph and o(2) in the mats were largely driven by the diel cycle of s ... | 2011 | 20740024 |
| eucapsitrione, an anti-mycobacterium tuberculosis anthraquinone derivative from the cultured freshwater cyanobacterium eucapsis sp. | eucapsitrione (1), an anthraquinone derivative with an indeno-anthracene-trione skeleton, was isolated from the cyanobacterium eucapsis sp. (utex 1519) by bioassay-guided fractionation. the chemical structure was determined by analyzing ms and 1d and 2d nmr spectroscopic data. eucapsitrione (1) showed anti-mycobacterium tuberculosis activity in the microplate alamar blue assay and low-oxygen-recovery assay with mic values of 3.1 and 6.4 microm, respectively. | 2010 | 20795743 |
| devt (alr4674), resembling a ser/thr protein phosphatase, is essential for heterocyst function in the cyanobacterium anabaena sp. pcc 7120. | heterocyst-forming cyanobacteria are able to perform oxygenic photosynthesis and nitrogen fixation simultaneously in the same filament, by restricting the highly o(2)-sensitive nitrogenase to specialized cells, the heterocysts. a remarkable change in morphology and metabolism accompanies the differentiation of heterocysts, which only occurs when no source of combined nitrogen is available. in this study, we characterized devt (alr4674), a putative protein phosphatase from anabaena pcc 7120. muta ... | 2010 | 20798164 |
| influence of a toxic microcystis aeruginosa strain on glutathione synthesis and glutathione-s-transferase activity in common carp cyprinus carpio (teleostei: cyprinidae). | we evaluated the effects of aqueous extracts of the cyanobacterium-producing microcystin (mc), microcystis aeruginosa (strain rst9501), on detoxification capacity and glutathione (gsh) synthesis in liver, brain, gill, and muscle-as well as apoptotic protease (calpain) activity in liver and brain-in the common carp cyprinus carpio (teleostei: cyprinidae). experimental groups were defined as follows: (1) control (ctr); (2) carp treated with an aqueous extract from the toxic cyanobacteria m. aerugi ... | 2011 | 20809345 |
| functional genomic analysis of an uncultured δ-proteobacterium in the sponge cymbastela concentrica. | marine sponges are ancient, sessile, filter-feeding metazoans, which represent a significant component of the benthic communities throughout the world. sponges harbor a remarkable diversity of bacteria, however, little is known about the functional properties of such bacterial symbionts. in this study, we present the genomic and functional characterization of an uncultured δ-proteobacterium associated with the sponge cymbastela concentrica. we show that this organism represents a novel phylogene ... | 2011 | 20811472 |
| nucleus-independent control of the rubisco operon by the plastid-encoded transcription factor ycf30 in the red alga cyanidioschyzon merolae. | chloroplasts originated from a cyanobacterium, which was engulfed by a primitive eukaryotic host cell. during evolution, chloroplasts have largely lost their autonomy due to the loss of many genes from their own genomes. consequently, expression of genes encoded in the chloroplast genome is mainly controlled by the factors transferred from the cytosol to chloroplasts. however, chloroplast genomes of glaucophytes and red algae have retained some transcription factors (hypothetical chloroplast ope ... | 2010 | 20813908 |
| the genetic and molecular basis for sunscreen biosynthesis in cyanobacteria. | ultraviolet uv-a and uv-b radiation is harmful to living systems, causing damage to biological macromolecules. an important strategy for dealing with uv exposure is the biosynthesis of small-molecule sunscreens. among such metabolites, the mycosporine and mycosporine-like amino acids (maas) are remarkable for their wide phylogenetic distribution and their unique chemical structures. here, we report the identification of a maa biosynthetic gene cluster in a cyanobacterium and the discovery of ana ... | 2010 | 20813918 |
| variability in the response of the cyanobacterium nodularia spumigena to nitrogen supplementation. | nodularia spumigena is a filamentous cyanobacterium that is commonly found in brackish water bodies. the species is capable of fixing atmospheric nitrogen in specialized cells termed heterocysts. n. spumigena dominates the annual toxic summer blooms in the baltic sea causing environmental and economical problems. we have previously demonstrated that n. spumigena strain av1 exhibits a different response to the presence of combined nitrogen as compared to model cyanobacteria such as nostoc pcc7120 ... | 2010 | 20820471 |
| identification of a gene essential for protoporphyrinogen ix oxidase activity in the cyanobacterium synechocystis sp. pcc6803. | protoporphyrinogen oxidase (protox) catalyses the oxidation of protoporphyrinogen ix to protoporphyrin ix during the synthesis of tetrapyrrole molecules. protox is encoded by the hemy gene in eukaryotes and by the hemg gene in many γ-proteobacteria, including escherichia coli. it has been suggested that other bacteria possess a yet unidentified type of protox. to identify a unique bacterial gene encoding protox, we first introduced the arabidopsis hemy gene into the genome of the cyanobacterium, ... | 2010 | 20823222 |
| cylindrocyclophanes with proteasome inhibitory activity from the cyanobacterium nostoc sp. | material collected from a parkway in the city of chicago afforded the isolation of a nostoc species (uic 10022a). the extract of this strain displayed significant inhibition of the 20s proteasome as well as antiproliferative activity against ht29, mcf7, nci-h460, and sf268 cancer cell lines. a standardized dereplication protocol allowed for the rapid identification of three known (11-13) and nine new (1-9) chlorinated cylindrocyclophanes from less than 100 mg of organic extract. scale-up isolati ... | 2010 | 20825206 |
| unusual radioresistance of nitrogen-fixing cultures of anabaena strains. | nitrogen-fixing cultures of two species of the filamentous, heterocystous cyanobacterium anabaena, namely anabaena sp. strain l-31 and anabaena torulosa were found to be highly tolerant to 60co gamma radiation. no adverse effect on diazotrophic growth and metabolism were observed up to a dose of 5 kgy. at higher doses, radiation tolerance showed a correspondence with the inherent osmotolerance, with anabaena l-31 being the more radiation tolerant as well as osmotolerant strain. in anabaena l-31, ... | 2010 | 20826952 |
| key dynamics of conserved asparagine in a cryptochrome/photolyase family protein by fourier transform infrared spectroscopy. | cryptochromes (crys) and photolyases (phrs) are flavoproteins that contain an identical cofactor (flavin adenine dinucleotide, fad) within the same protein architecture but whose physiological functions are entirely different. in this study, we investigated light-induced conformational changes of a cyanobacterium cry/phr-like protein (scry-dash) with uv-visible and fourier transform infrared (ftir) spectroscopy. we developed a system for measuring light-induced difference spectra under the conce ... | 2010 | 20828134 |
| isolation and molecular characterization of a multicellular cyanobacterium, limnothrix/pseudanabaena sp. strain abrg5-3. | a cyanobacterium, semi-filamentous multicellular strain abrg5-3, was isolated and its unique nature was characterized. this axenic strain formed colonies and was motile on an agarose plate. the 16s rrna gene of abrg5-3 exhibited similarities to those of the limnothrix and pseudanabaena strains, which are known as filamentous and nonheterocystous cyanobacteria. peaks in absorbance for the accumulation of chlorophyll a, phycocyanin, and phycoerythrin were observed in the cell extract. natural sepa ... | 2010 | 20834156 |
| effects of the antibiotic growth promoters flavomycin and florfenicol on the autochthonous intestinal microbiota of hybrid tilapia (oreochromis niloticus ♀ × o. aureus ♂). | the 16s rdna pcr-dgge and rpob quantitative pcr (rq-pcr) techniques were used to evaluate the effects of dietary flavomycin and florfenicol on the autochthonous intestinal microbiota of hybrid tilapia. the fish were fed four diets: control, dietary flavomycin, florfenicol and their combination. after 8 weeks of feeding, 6 fish from each cage were randomly chosen for the analysis. the total number of intestinal bacteria was determined by rq-pcr. the results showed that dietary antibiotics signifi ... | 2010 | 20844867 |