| Cannabinomimetic lipid from a marine cyanobacterium. | NMR-guided fractionation of two independent collections of the marine cyanobacteria Lyngbya majuscula obtained from Papua New Guinea and Oscillatoria sp. collected in Panama led to the isolation of the new lipids serinolamide A (3) and propenediester (4). Their structures were determined by NMR and MS data analysis. Serinolamide A (3) exhibited a moderate agonist effect and selectivity for the CB1 cannabinoid receptor (Ki=1.3 µM, >5-fold) and represents the newest addition to the known cannabino ... | 2011 | 21999614 |
| the effect of exogenous β-n-methylamino-l: -alanine on the growth of synechocystis pcc6803. | β-n-methylamino-l: -alanine (bmaa), a non-proteinogenic amino acid, has been detected in a range of cyanobacteria, including terrestrial, aquatic, free living and endosymbiotic species. the widespread occurrence of cyanobacteria in the environment raises concerns regarding the ecological and toxicological impact of bmaa, and consequently, studies have focussed extensively on the toxicity and environmental impact of bmaa, while no research has addressed the ecophysiological or metabolic role of t ... | 2011 | 21994035 |
| mapping photoautotrophic metabolism with isotopically nonstationary (13)c flux analysis. | understanding in vivo regulation of photoautotrophic metabolism is important for identifying strategies to improve photosynthetic efficiency or re-route carbon fluxes to desirable end products. we have developed an approach to reconstruct comprehensive flux maps of photoautotrophic metabolism by computational analysis of dynamic isotope labeling measurements and have applied it to determine metabolic pathway fluxes in the cyanobacterium synechocystis sp. pcc6803. comparison to a theoretically pr ... | 2011 | 21907300 |
| expression, purification, crystallization and preliminary x-ray crystallographic studies of alkyl hydroperoxide reductase (ahpc) from the cyanobacterium anabaena sp. pcc 7120. | alkyl hydroperoxide reductase (ahpc) is a key component of a large family of thiol-specific antioxidant (tsa) proteins distributed among prokaryotes and eukaryotes. ahpc is involved in the detoxification of reactive oxygen species (ros) and reactive sulfur species (rss). sequence analysis of ahpc from the cyanobacterium anabaena sp. pcc 7120 shows that this protein belongs to the 1-cys class of peroxiredoxins (prxs). it has recently been reported that enhanced expression of this protein in esche ... | 2011 | 22102027 |
| Sucrose synthase in unicellular cyanobacteria and its relationship with salt and hypoxic stress. | Higher plants and cyanobacteria metabolize sucrose (Suc) by a similar set of enzymes. Suc synthase (SuS, A/UDP-glucose: D: -fructose 2-a-D: -glucosyl transferase) catalyzes a reversible reaction. However, it is in the cleavage of Suc that this enzyme plays an important role in vivo, providing sugar nucleotides for polysaccharide biosynthesis. In cyanobacteria, SuS occurrence has been reported in heterocyst-forming strains, where it was shown to be involved also in nitrogen fixation. We investiga ... | 2011 | 22113826 |
| circadian transcriptional regulation by the posttranslational oscillator without de novo clock gene expression in synechococcus. | circadian rhythms are a fundamental property of most organisms, from cyanobacteria to humans. in the unicellular obligately photoautotrophic cyanobacterium synechococcus elongatus pcc 7942, essentially all promoter activities are controlled by the kaiabc-based clock under continuous light conditions. when synechococcus cells are transferred from the light to continuous dark (dd) conditions, the expression of most genes, including the clock genes kaia and kaibc, is rapidly down-regulated, whereas ... | 2011 | 21896749 |
| membrane anchoring of aminoacyl-trna synthetases by convergent acquisition of a novel protein domain. | four distinct aminoacyl-trna synthetases (aarss) found in some cyanobacterial species contain a novel protein domain that bears two putative transmembrane helices. this caad domain is present in glutamyl-, isoleucyl-, leucyl-, and valyl-trna synthetases, the latter of which has probably recruited the domain more than once during evolution. deleting the caad domain from the valyl-trna synthetase of anabaena sp. pcc 7120 did not significantly modify the catalytic properties of this enzyme, suggest ... | 2011 | 21965654 |
| evidence for direct binding between hetr from anabaena sp. pcc 7120 and pats-5. | hetr, master regulator of heterocyst differentiation in the filamentous cyanobacterium anabaena sp. strain pcc 7120, stimulates heterocyst differentiation via transcriptional autoregulation and is negatively regulated by pats and hetn, both of which contain the active pentapeptide rgsgr. however, the direct targets of pats and hetn remain uncertain. here, we report experimental evidence for direct binding between hetr and the c-terminal rgsgr pentapeptide, pats-5. strains with a hetr allele codi ... | 2011 | 21942265 |
| acclimation to high-light conditions in cyanobacteria: from gene expression to physiological responses. | photosynthetic organisms have evolved various acclimatory responses to high-light (hl) conditions to maintain a balance between energy supply (light harvesting and electron transport) and consumption (cellular metabolism) and to protect the photosynthetic apparatus from photodamage. the molecular mechanism of hl acclimation has been extensively studied in the unicellular cyanobacterium synechocystis sp. pcc 6803. whole genome dna microarray analyses have revealed that the change in gene expressi ... | 2012 | 22006212 |
| detection of bioactive exometabolites produced by the filamentous marine cyanobacterium geitlerinema sp. | marine cyanobacteria are noted for their ability to excrete metabolites with biotic properties. this paper focuses on such exometabolites obtained from the culture of the marine filamentous cyanobacterium geitlerinema sp. strain, their purification and subsequent analyses. by this means the recoveries of the active compounds, a prerequisite for properly determining their concentration, are quantified here for the first time. we demonstrate a new procedure using amberlite xad-1180 resin in combin ... | 2011 | 22160344 |
| exploiting the autofluorescent properties of photosynthetic pigments for analysis of pigmentation and morphology in live fremyella diplosiphon cells. | fremyella diplosiphon is a freshwater, filamentous cyanobacterium that exhibits light-dependent regulation of photosynthetic pigment accumulation and cellular and filament morphologies in a well-known process known as complementary chromatic adaptation (cca). one of the techniques used to investigate the molecular bases of distinct aspects of cca is confocal laser scanning microscopy (clsm). clsm capitalizes on the autofluorescent properties of cyanobacterial phycobiliproteins and chlorophyll a. ... | 2010 | 22163584 |
| tunable pores for measuring concentrations of synthetic and biological nanoparticle dispersions. | scanning ion occlusion sensing (sios), a technique that uses a tunable pore to detect the passage of individual nano-scale objects, is applied here for the rapid, accurate and direct measurement of synthetic and biological nanoparticle concentrations. sios is able to characterize smaller particles than other direct count techniques such as flow cytometry or coulter counters, and the direct count avoids approximations such as those necessary for turbidity measurements. measurements in a model sys ... | 2012 | 22019099 |
| Microbial Community Changes Elicited by Exposure to Cyanobacterial Allelochemicals. | An increasing body of evidence points out that allelopathy may be an important process shaping microbial communities in aquatic ecosystems. Cyanobacteria have well-documented allelopathic properties, mainly derived from the evaluation of the activity of allelopathic extracts or pure compounds towards monocultures of selected target microorganisms. Consequently, little is known regarding the community dynamics of microorganisms associated with allelopathic interactions. In this laboratory-based s ... | 2011 | 21947429 |
| spectroscopic study of the cp43' complex and the psi-cp43' supercomplex of the cyanobacterium synechocystis pcc 6803. | the psi-cp43' supercomplex of the cyanobacterium synechocystis pcc 6803, grown under iron-starvation conditions, consists of a trimeric core photosystem i (psi) complex and an outer ring of 18 cp43' light-harvesting complexes. we have investigated the electronic structure and excitation energy transfer (eet) pathways within the cp43' (also known as the isia gene product) ring using low-temperature absorption, fluorescence, fluorescence excitation, and hole-burning (hb) spectroscopies. analysis o ... | 2011 | 21978372 |
| femtosecond photodynamics of the red/green cyanobacteriochrome npr6012g4 from nostoc punctiforme. 2. reverse dynamics. | phytochromes are red/far-red photosensory proteins that utilize photoisomerization of a linear tetrapyrrole (bilin) chromophore to photoconvert reversibly between red- and far-red-absorbing forms (p(r) and p(fr), respectively). cyanobacteriochromes (cbcrs) are related photosensory proteins with more diverse spectral sensitivity. the mechanisms that underlie this spectral diversity have not yet been fully elucidated. one of the main cbcr subfamilies photoconverts between a red-absorbing 15z groun ... | 2011 | 22148731 |
| identification of three novel antisense rnas in the fur locus from unicellular cyanobacteria. | the interplay between fur (ferric uptake regulator) proteins and small, non-coding rnas has been described as a key regulatory loop in several bacteria. in the filamentous cyanobacterium anabaena sp. pcc 7120, a large dicistronic transcript encoding the putative membrane protein alr1690 and an α-fura rna is involved in the modulation of the global regulator fura. in this work we report the existence of three novel antisense rnas in cyanobacteria and show that a cis α-fura rna is conserved in ver ... | 2011 | 21921103 |
| Response and resilience of soil biocrust bacterial communities to chronic physical disturbance in arid shrublands. | The impact of 10 years of annual foot trampling on soil biocrusts was examined in replicated field experiments at three cold desert sites of the Colorado Plateau, USA. Trampling detrimentally impacted lichens and mosses, and the keystone cyanobacterium, Microcoleus vaginatus, resulting in increased soil erosion and reduced C and N concentrations in surface soils. Trampled biocrusts contained approximately half as much extractable DNA and 20-52% less chlorophyll a when compared with intact biocru ... | 2011 | 22113374 |
| Novel ATP-driven pathway of glycolipid export involving TolC protein. | Upon depletion of combined nitrogen, N(2)-fixing heterocysts are formed from vegetative cells in the case of the filamentous cyanobacterium Anabaena sp. strain PCC 7120. A heterocyst-specific layer composed of glycolipids (heterocyst envelope glycolipids (HGLs)) that functions as an O(2) diffusion barrier is deposited over the heterocyst outer membrane and is surrounded by an outermost heterocyst polysaccharide envelope. Mutations in any gene of the devBCA operon or tolC result in the absence of ... | 2011 | 21917923 |
| toxicity of the cyanobacterium limnothrix ac0243 to male balb/c mice. | a growing list of freshwater cyanobacteria are known to produce toxic agents, a fact which makes these organisms of concern to water authorities. a cultured strain of limnothrix (ac0243) was recently shown to have toxic effects in in vitro bioassays. it did not produce any of the known cyanobacterial toxins. the intrapertoneal toxicity of aqueous extracts of the material was therefore tested in mice to determine whether the observed effects might be of public health relevance to drinking water s ... | 2011 | 22119368 |
| A novel cyanophage with a cyanobacterial nonbleaching protein a gene in the genome. | A cyanophage, PaV-LD, has been isolated from harmful filamentous cyanobacterium Planktothrix agardhii in Lake Donghu, a shallow freshwater lake in China. Here, we present the cyanophage's genomic organization and major structural proteins. The genome is a 95,299-bp-long, linear double-stranded DNA and contains 142 potential genes. BLAST searches revealed 29 proteins of known function in cyanophages, cyanobacteria, or bacteria. Thirteen major structural proteins ranging in size from 27 kDa to 172 ... | 2012 | 22031930 |
| Low-carbon acclimation in carboxysome-less and photorespiratory mutants of the cyanobacterium Synechocystis sp. strain PCC 6803. | Using metabolic and transcriptomic phenotyping, we studied acclimation of cyanobacteria to low-carbon (LC) conditions and the requirements for coordinated alteration of metabolism and gene expression. To analyze possible metabolic signals for LC sensing and compensating reactions, the carboxysome-less mutant ?ccmM and the photorespiratory mutant ?glcD1/D2 were compared with wild-type (WT) Synechocystis. Metabolic phenotyping revealed accumulation of 2-phosphoglycolate (2PG) in ?ccmM and of glyco ... | 2011 | 22096149 |
| identification of an oxygenic reaction center psbadc operon in the cyanobacterium gloeobacter violaceus pcc 7421. | gloeobacter violaceus, the earliest diverging oxyphotobacterium (cyanobacterium) on the 16s ribosomal rna tree, has five copies of the photosystem ii psba gene encoding the d1 reaction center protein subunit. these copies are widely distributed throughout the 4.6 mbp genome with only one copy colocalizing with other psii subunits, in marked contrast to all other psba genes in all publicly available sequenced genomes. a clustering of two other psb genes around psba3 (glr2322) is unique to gloeoba ... | 2011 | 21903678 |
| Prevalence of Ca2+-ATPase-Mediated Carbonate Dissolution among Cyanobacterial Euendoliths. | Recent physiological work has shown that the filamentous euendolithic cyanobacterium Mastigocoleus testarum (strain BC008) is able to bore into solid carbonates using Ca(2+)-ATPases to take up Ca(2+) from the medium at the excavation front, promoting dissolution of CaCO(3) there. It is not known, however, if this is a widespread mechanism or, rather, a unique capability of this model strain. To test this, we undertook a survey of multispecies euendolithic microbial assemblages infesting natural ... | 2012 | 22038600 |
| An ATP-grasp ligase involved in the last biosynthetic step of the iminomycosporine shinorine in Nostoc punctiforme ATCC 29133. | We investigated the genetic basis for mycosporine sunscreen biosynthesis by the cyanobacterium Nostoc punctiforme ATCC 29133. Heterologous expression in Escherichia coli of three contiguous N. punctiforme genes (NpR5600, NpR5599, and NpR5598, here named mysA, mysB, and mysC, respectively) led to the production of mycosporine-glycine, an oxomycosporine. Additional expression of gene NpF5597 (mysD) led to the conversion of mycosporine-glycine into iminomycosporines (preferentially shinorine but al ... | 2011 | 21890703 |
| Isolation and characterization of the unicellular diazotrophic cyanobacterium Group C TW3 from the tropical western Pacific Ocean. | A unicellular diazotrophic cyanobacterium strain of Group C, designated TW3, was isolated from the oligotrophic Kuroshio Current of the western Pacific Ocean. To our knowledge, this represents the first successful laboratory culture of a Group C unicellular diazotroph from oceanic water. TW3 cells are green rods, 2.5-3.0 µm in width and 4.0-6.0 µm in length. Phylogenetic analyses of both 16S rRNA and nifH gene fragments indicated that the TW3 sequences were over 98% identical to those of the pre ... | 2011 | 21981769 |
| The role of the PsbU subunit in the light sensitivity of PSII in the cyanobacterium Synechococcus 7942. | In the present study we investigated the role of the PsbU subunit in the electron transport characteristics and light sensitivity of the Photosystem II complex. The experiments were performed by using an earlier characterized PsbU-less mutant of the cyanobacterium Synechococcus PCC 7942, which has enhanced antioxidant capacity (Balint et al. FEBS Lett. 580 (2006) 2117-2122). Flash induced Chl fluorescence measurements in the presence and absence of the electron transport inhibitor DCMU showed th ... | 2011 | 21944715 |
| oep80, an essential protein paralogous to the chloroplast protein translocation channel toc75, exists as a 70-kd protein in the arabidopsis thaliana chloroplast outer envelope. | toc75 and oep80 are paralogous proteins found in the viridiplantae lineages, and appear to have evolved from a protein in the outer membrane of an ancient cyanobacterium. toc75 is known to act as a protein translocation channel at the outer membrane of the chloroplast envelope, whereas the exact function of oep80 is not understood. in arabidopsis thaliana, each protein is encoded by a single gene, and both are essential for plant viability from embryonic stages onward. sequence annotation and im ... | 2012 | 22094888 |
| the role of microcystins in maintaining colonies of bloom-forming microcystis spp. | microcystis is a cosmopolitan genus of cyanobacteria and occurs in many different forms. large surface blooms of the cyanobacterium are well known in eutrophic lakes throughout the globe. we evaluated the role of microcystins (mcs) in promoting and maintaining bloom-forming cell aggregates at environmentally relevant mc concentrations (0.25-10 µg l(-1) ). mcs significantly enhanced microcystis colony sizes. colonial diameters in microcystin-rr (mc-rr)-treated cultures (at 1 µg l(-1) ) were signi ... | 2011 | 22040118 |
| colour evaluation of a phycobiliprotein-rich extract obtained from nostoc pcc9205 in acidic solutions and yogurt. | background: phycobiliproteins are coloured proteins produced by cyanobacteria, which have several applications because of their colour properties. however, there is no available information about the colour stability of phycobiliproteins from nostoc sp. in food systems. the aim of this work was to study the colour stability of a purple-coloured phycobiliprotein-rich extract from the cyanobacterium nostoc pcc9205 in acidic solutions and yogurt. results: variations of ph for nostoc pcc9205 extract ... | 2011 | 22095681 |
| effect of light quality on the c-phycoerythrin production in marine cyanobacteria pseudanabaena sp. isolated from gujarat coast, india. | the isolated cyanobacterium containing biopigments like chlorophyll-a, phycoerythrin, phycocyanin, and carotenoid was cultured under different quality of light modes to ascertain biomass and pigment productivity. on the basis of 16s rrna gene sequence, the isolate was identified as pseudanabaena sp. maximum biomass concentration obtained in white-, blue-, and green-light was 0.82, 0.94, and 0.89 g/l, respectively. it was observed that maximum phycoerythrin production was in green light (39.2 mg/ ... | 2012 | 21906679 |
| development of a halotolerant community in the st. lucia estuary (south africa) during a hypersaline phase. | the st. lucia estuary, africa's largest estuarine lake, is currently experiencing unprecedented freshwater deprivation which has resulted in a northward gradient of drought effects, with hypersaline conditions in its northern lakes. | 2012 | 22238676 |
| nuclear, mitochondrial and plastid gene phylogenies of dinophysis miles (dinophyceae): evidence of variable types of chloroplasts. | the dinophysis genus is an ecologically and evolutionarily important group of marine dinoflagellates, yet their molecular phylogenetic positions and ecological characteristics such as trophic modes remain poorly understood. here, a population of dinophysis miles var. indica was sampled from south china sea in march 2010. nuclear ribosomal rna gene (rdna) ssu, its1-5.8s-its2 and lsu, mitochondrial genes encoding cytochrome b (cob) and cytochrome c oxidase subunit i (cox1), and plastid rdna ssu we ... | 2011 | 22242118 |
| sublethal dietary effects of microcystis on sacramento splittail, pogonichthys macrolepidotus. | the presence of the toxic cyanobacterium microcystis in the upper san francisco estuary (sfe) since 1999 is a potential but to date an unquantified threat to the health and survival of aquatic organisms, such as fish and zooplankton. the microcystins (mcs) predominantly in the lr-form (mc-lr) contained in microcystis is hepatotoxic and a potential threat to the fishery. this study was conducted to determine the effects of dietary exposure of the endemic sacramento splittail, pogonichthys macrole ... | 2011 | 22245626 |
| toxopsis calypsus gen. nov., sp. nov. (cyanobacteria, nostocales) from cave 'francthi', peloponnese, greece - morphological and molecular evaluation. | one new cyanobacterial genus toxopsis lamprinou & pantazidou gen. nov. was found in fresh material of cave 'francthi'(peloponnese, greece) and isolated in cultures; additionally, ecological data of the sampling sites are provided concerning the environmental parameters [photosynthetically active radiation (par), temperature (t), relative humidity (rh)]. morphological characters and the life cycle of the type species toxopsis calypsus lamprinou & pantazidou sp. nov. were studied under lm, sem and ... | 2012 | 22247210 |
| double mutation in photosystem ii reaction centers and elevated co(2) grant thermotolerance to mesophilic cyanobacterium. | photosynthetic biomass production rapidly declines in mesophilic cyanobacteria grown above their physiological temperatures largely due to the imbalance between degradation and repair of the d1 protein subunit of the heat susceptible photosystem ii reaction centers (psiirc). here we show that simultaneous replacement of two conserved residues in the d1 protein of the mesophilic synechocystis sp. pcc 6803, by the analogue residues present in the thermophilic thermosynechococcus elongatus, enables ... | 2011 | 22216094 |
| unique properties of eukaryote-type actin and profilin horizontally transferred to cyanobacteria. | a eukaryote-type actin and its binding protein profilin encoded on a genomic island in the cyanobacterium microcystis aeruginosa pcc 7806 co-localize to form a hollow, spherical enclosure occupying a considerable intracellular space as shown by in vivo fluorescence microscopy. biochemical and biophysical characterization reveals key differences between these proteins and their eukaryotic homologs. small-angle x-ray scattering shows that the actin assembles into elongated, filamentous polymers wh ... | 2012 | 22253827 |
| life cycle energy and greenhouse gas profile of a process for the production of ammonium sulfate from nitrogen-fixing photosynthetic cyanobacteria. | in this paper, an alternative means for nitrogen fixation that may consume less energy and release less greenhouse gases than the haber-bosch process is explored. a life-cycle assessment was conducted on a process to: culture the cyanobacterium, anabaena sp. atcc 33047, in open ponds; harvest the biomass and exopolysaccharides and convert these to biogas; strip and convert the ammonia from the biogas residue to ammonium sulfate; dry the ammonium sulfate solution to ammonium sulfate crystals and ... | 2011 | 22226591 |
| isolation of cyanophycin from tobacco and potato plants with constitutive plastidic cpha(te) gene expression. | a chimeric cyanophycin synthetase gene composed of the cpha(te) coding region from the cyanobacterium thermosynechococcus elongatus bp-1, the constitutive 35s promoter and the plastid targeting sequence of the integral photosystem ii protein psby was transferred to the tobacco variety petit havanna sri and the commercial potato starch production variety albatros. the resulting constitutive expression of cyanophycin synthetase leads to polymer contents in potato leaf chloroplasts of up to 35mg/g ... | 2012 | 22244982 |
| identification of two residues essential for the stringent substrate specificity and active site stability of the prokaryotic l-arginine:glycine amidinotransferase cyra. | a novel prokaryotic l-arginine:glycine amidinotransferase (cyra, ec 2.1.4.1) is involved in the biosynthesis of the polyketide-derived cytotoxin cylindrospermopsin in the cyanobacterium cylindrospermopsis raciborskii awt250 and was previously characterised with regards to kinetic mechanism and substrate specificity (muenchhoff et al., febs j277: 3844). in order to elucidate the structure-function-stability relationship of this enzyme, two amino acid residues in its active site were replaced with ... | 2012 | 22221800 |
| determinants for substrate specificity of the bacterial pp2c protein phosphatase tppha from thermosynechococcus elongatus. | members of the mg(2+) - or mn(2+) -dependent protein phosphatases/pp2c-like serine/threonine phosphatases (ppm/pp2c) are abundant and widely distributed in prokaryotes and eukaryotes, where they regulate diverse signal transduction pathways. despite low sequence conservation, the structure of their catalytic core is highly conserved except for a flexible loop termed the flap subdomain. bacterial ppm/pp2c members without c- or n-terminal regulatory domains still recognize their substrates. based ... | 2011 | 22212593 |
| net light-induced oxygen evolution in photosystem i deletion mutants of the cyanobacterium synechocystis sp. pcc 6803. | oxygenic photosynthesis in cyanobacteria, algae, and plants requires photosystem ii (psii) to extract electrons from h(2)o and depends on photosystem i (psi) to reduce nadp(+). here we demonstrate that mixotrophically-grown mutants of the cyanobacterium synechocystis sp. pcc 6803 that lack psi (δpsi) are capable of net light-induced o(2) evolution in vivo. the net light-induced o(2) evolution requires glucose and can be sustained for more than 30min. utilizing electron transport inhibitors and c ... | 2012 | 22266340 |