Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| slippery when wet: phylogeny and character evolution in the gelatinous cyanobacterial lichens (peltigerales, ascomycetes). | many lichen fungi form symbioses with filamentous nostoc cyanobacteria, which cause the lichen to swell and become extremely gelatinous when moist. within the lecanoromycetes, such gelatinous lichens are today mainly classified in the collemataceae (peltigerales, ascomycota). we performed bayesian mcmc, maximum likelihood, and maximum parsimony analyses of three independent markers (mtssu rdna, nulsu rdna, and rpb1), to improve our understanding of the phylogeny and classification in the peltige ... | 2009 | 19695332 |
| improvement and analysis of computational methods for prediction of residual dipolar couplings. | we describe a new, computationally efficient method for computing the molecular alignment tensor based on the molecular shape. the increase in speed is achieved by re-expressing the problem as one of numerical integration, rather than a simple uniform sampling (as in the pales method), and by using a convex hull rather than a detailed representation of the surface of a molecule. this method is applicable to bicelles, peg/hexanol, and other alignment media that can be modeled by steric restrictio ... | 2009 | 19700353 |
| new insights into the role of fur proteins: furb (all2473) from anabaena protects dna and increases cell survival under oxidative stress. | fur (ferric uptake regulator) is a prokaryotic transcriptional regulator that controls a large number of genes mainly related to iron metabolism. several fur homologues with different physiological roles are frequently found in the same organism. the genome of the filamentous cyanobacterium anabaena (nostoc) sp. pcc 7120 codes for three different fur genes. fura is an essential protein involved in iron homoeostasis that also modulates dinitrogen fixation. fura interacts with haem, impairing its ... | 2009 | 18945213 |
| screening for acetylcholinesterase inhibitory activity in cyanobacteria of the genus nostoc. | fifty-four cyanobacterial strains of the genus nostoc from different habitats were screened for acetylcholinesterase inhibitory activity. water-methanolic extracts from freeze-dried biomasses were tested for inhibitory activity using ellman's spectrophotometric method. acetylcholinesterase inhibitory activity higher than 90% was found in the crude extracts of nostoc sp. str. lukesova 27/97 and nostoc ellipsosporum rabenh. str. lukesova 51/91. extracts from nostoc ellipsosporum str. lukesova 52/9 ... | 2009 | 18951237 |
| the 2a resolution crystal structure of hetl, a pentapeptide repeat protein involved in regulation of heterocyst differentiation in the cyanobacterium nostoc sp. strain pcc 7120. | the hetl gene from the cyanobacterium nostoc sp. pcc 7120 encodes a 237 amino acid protein (25.6kda) containing 40 predicted tandem pentapeptide repeats. nostoc sp. pcc 7120 is a filamentous cyanobacterium that forms heterocysts, specialized cells capable of fixing atmospheric n(2) during nitrogen starvation in its aqueous environment. under these conditions, heterocysts occur in a regular pattern of approximately one out of every 10-15 vegetative cells. heterocyst differentiation is highly regu ... | 2009 | 18952182 |
| gobase: an organelle genome database. | the organelle genome database gobase, now in its 21st release (june 2008), contains all published mitochondrion-encoded sequences (approximately 913,000) and chloroplast-encoded sequences (approximately 250,000) from a wide range of eukaryotic taxa. for all sequences, information on related genes, exons, introns, gene products and taxonomy is available, as well as selected genome maps and rna secondary structures. recent major enhancements to database functionality include: (i) addition of an in ... | 2009 | 18953030 |
| an evaluation of four phylogenetic markers in nostoc: implications for cyanobacterial phylogenetic studies at the intrageneric level. | the success of some phylogenetic markers in cyanobacteria owes to the design of cyanobacteria-specific primers, but a few studies have directly investigated the evolution "behavior" of the loci. in this study, we performed a case study in nostoc to evaluate rpoc1, hetr, rbclx, and 16s rrna-trna(ile)-trna(ala)-23s rrna internal transcribed spacer (its) as phylogenetic markers. the results indicated that the gene trees of these loci are not congruent with the phylogeny based on 16s rrna gene. the ... | 2009 | 18972163 |
| the role of the c-terminal region of cyanophycin synthetase from nostoc ellipsosporum ne1 in its enzymatic activity and thermostability: a key function of glu(856). | the biosynthesis of cyanophycin granule polypeptides is catalyzed by cyanophycin synthetase, cpha. in this study, the role of the c-terminal region of cpha from nostoc ellipsosporum ne1, cpha(ne1), was analyzed using a tailor-made c-terminus truncated library. the expression level of truncated cpha(ne1) in e. coli depended on the stop codons that were used. the expression vector that had the amber stop codon tag produced more than twice amount of cpha(ne1) as a vector that contained the ochre co ... | 2009 | 18977318 |
| crystal structure of npun_r1517, a putative negative regulator of heterocyst differentiation from nostoc punctiforme pcc 73102. | 2009 | 19089958 | |
| physiological characterization and electron microscopic investigation of cyanobacteria associated with wheat rhizosphere. | physiological attributes of a set of cyanobacterial strains, isolated from the rhizosphere of wheat (var. hd 2687), identified as belonging to the genera calothrix (n = 3), westiellopsis (1), hapalosiphon (2) and nostoc (2), were axenized and evaluated. the concentrated culture filtrates of three cyanobacterial strains - c. ghosei, h. intricatus and nostoc sp. were able to enhance germination percentage, radicle and coleoptile length in inhibition experiments with wheat seeds. indole-3-acetic ac ... | 2009 | 19330544 |
| molecular characterization and the effect of salinity on cyanobacterial diversity in the rice fields of eastern uttar pradesh, india. | salinity is known to affect almost half of the world's irrigated lands, especially rice fields. furthermore, cyanobacteria, one of the critical inhabitants of rice fields have been characterized at molecular level from many different geographical locations. this study, for the first time, has examined the molecular diversity of cyanobacteria inhabiting indian rice fields which experience various levels of salinity. | 2009 | 19344531 |
| solution structure of dnae intein from nostoc punctiforme: structural basis for the design of a new split intein suitable for site-specific chemical modification. | naturally split dnae intein from nostoc punctiforme (npu) has robust protein trans-splicing activity and high tolerance of sequence variations at the splicing junctions. we determined the solution structure of a single chain variant of npudnae intein by nmr spectroscopy. based on the nmr structure and the backbone dynamics of the single chain npudnae intein, we designed a functional split variant of the npudnae intein having a short c-terminal half (c-intein) composed of six residues. in vivo an ... | 2009 | 19344715 |
| current trends in high throughput proteomics in cyanobacteria. | advancements in genome sequencing and high throughput proteomics of cyanobacterial strains led to 13 published reports, from a small number of laboratories. these successful studies focused on synechocystis, nostoc and anabaena strains, prochlorococcus, and halotolerant euhalothece. the implications of emerging quantitative aspects developed and applied in these large-scale studies are assessed in the wake of advanced cyanobacterial research. furthermore, contributions from traditional and early ... | 2009 | 19345218 |
| the naturally split npu dnae intein exhibits an extraordinarily high rate in the protein trans-splicing reaction. | we have studied the naturally split alpha subunit of the dna polymerase iii (dnae) intein from nostoc punctiforme pcc73102 (npu) using purified proteins and determined an apparent first-order rate constant of (1.1+/-0.2)x10(-2) s(-1) at 37 degrees c. this represents the highest rate reported for the protein trans-splicing reaction so far (t(1/2) of approximately 60s). furthermore, the reaction was very robust and high-yielding with respect to different extein sequences, temperatures from 6 to 37 ... | 2009 | 19302791 |
| role of ntca, a cyanobacterial global nitrogen regulator, in the regulation of sucrose metabolism gene expression in anabaena sp. pcc 7120. | in the heterocyst-forming cyanobacterium anabaena sp. pcc 7120 (also known as nostoc sp. pcc 7120), it has been shown that spsb and susa, the genes coding for proteins related to sucrose synthesis and cleavage, respectively, exhibit converse expression regarding the nitrogen source. in the nitrogen-fixing filament, spsb expression is mostly localized to the heterocysts and susa is only expressed in vegetative cells. the aim of this work was to investigate the participation of ntca, a global nitr ... | 2009 | 19082579 |
| an enzymatic cyclopentyl[b]indole formation involved in scytonemin biosynthesis. | previous studies of the biosynthetic enzymes involved in the assembly of scytonemin (1), a cyanobacterial sunscreen, have identified beta-ketoacid 2 as an important intermediate that is produced by thdp-dependent enzyme scya. we now report that scyc, previously annotated as a hypothetical protein, catalyzes cyclization and decarboxylation of 2 to generate ketone 5. assembly of the cyclopentyl[b]indole structure in this manner has little precedent in the chemical literature. additional mechanisti ... | 2009 | 19780555 |
| overexpression, isolation, and spectroscopic characterization of the bidirectional [nife] hydrogenase from synechocystis sp. pcc 6803. | the bidirectional [nife] hydrogenase of the cyanobacterium synechocystis sp. pcc 6803 was purified to apparent homogeneity by a single affinity chromatography step using a synechocystis mutant with a strep-tag ii fused to the c terminus of hoxf. to increase the yield of purified enzyme and to test its overexpression capacity in synechocystis the psbaii promoter was inserted upstream of the hoxe gene. in addition, the accessory genes (hypf, c, d, e, a, and b) from nostoc sp. pcc 7120 were express ... | 2009 | 19801638 |
| 2-methylhopanoids are maximally produced in akinetes of nostoc punctiforme: geobiological implications. | 2-methylhopanes, molecular fossils of 2-methylbacteriohopanepolyol (2-mebhp) lipids, have been proposed as biomarkers for cyanobacteria, and by extension, oxygenic photosynthesis. however, the robustness of this interpretation is unclear, as 2-methylhopanoids occur in organisms besides cyanobacteria and their physiological functions are unknown. as a first step toward understanding the role of 2-mebhp in cyanobacteria, we examined the expression and intercellular localization of hopanoids in the ... | 2009 | 19811542 |
| isolation and characterization of a cyanobacterium-binding protein and its cell wall receptor in the lichen peltigera canina. | peltigera canina, a cyanolichen containing nostoc as cyanobiont, produces and secretes arginase to a medium containing arginine. secreted arginase acts as a lectin by binding to the surface of nostoc cells through a specific receptor which develops urease activity. the enzyme urease has been located in the cell wall of recently isolated cyanobionts. cytochemical detection of urease is achieved by producing a black, electron-dense precipitate of cobalt sulfide proceeding from co(2) evolved from u ... | 2009 | 19820309 |
| consumption of fa cai nostoc soup: a potential for bmaa exposure from nostoc cyanobacteria in china? | grown in arid regions of western china the cyanobacterium nostoc flagelliforme--called fa cai in mandarin and fat choy in cantonese--is wild-harvested and used to make soup consumed during new year's celebrations. high prices, up to $125 usd/kg, led to overharvesting in inner mongolia, ningxia, gansu, qinghai, and xinjiang. degradation of arid ecosystems, desertification, and conflicts between nostoc harvesters and mongol herdsmen concerned the chinese environmental authorities, leading to a gov ... | 2009 | 19929731 |
| structure of a bacterial dynamin-like protein lipid tube provides a mechanism for assembly and membrane curving. | proteins of the dynamin superfamily mediate membrane fission, fusion, and restructuring events by polymerizing upon lipid bilayers and forcing regions of high curvature. in this work, we show the electron cryomicroscopy reconstruction of a bacterial dynamin-like protein (bdlp) helical filament decorating a lipid tube at approximately 11 a resolution. we fitted the bdlp crystal structure and produced a molecular model for the entire filament. the bdlp gtpase domain dimerizes and forms the tube su ... | 2009 | 20064379 |
| do lichens domesticate photobionts like farmers domesticate crops? evidence from a previously unrecognized lineage of filamentous cyanobacteria. | phylogenetic diversity of lichen photobionts is low compared to that of fungal counterparts. most lichen fungi are thought to be associated with just four photobiont genera, among them the cyanobacteria nostoc and scytonema, two of the most important nitrogen fixers in humid ecosystems. although many nostoc photobionts have been identified using isolated cultures and sequences, the identity of scytonema photobionts has never been confirmed by culturing or sequencing. we investigated the phylogen ... | 2009 | 21628288 |
| a pulsed epr method to determine distances between paramagnetic centers with strong spectral anisotropy and radicals: the dead-time free ridme sequence. | methods to determine distances between paramagnetic metal centers and radicals are scarce. this is unfortunate because paramagnetic metal centers are frequent in biological systems and so far have not been employed much as distance markers. successful pulse sequences that directly target the dipolar interactions cannot be applied to paramagnetic metal centers with fast relaxation rates and large g-anisotropy, if no echos can be detected and the excitation bandwidth is not sufficient to cover a s ... | 2009 | 19758831 |
| structural features of the nostoc punctiforme debranching enzyme reveal the basis of its mechanism and substrate specificity. | the debranching enzyme nostoc punctiforme debranching enzyme (npde) from the cyanobacterium nostoc punctiforme (pcc73102) hydrolyzes the alpha-1,6 glycosidic linkages of malto-oligosaccharides. despite its high homology to cyclodextrin/pullulan (cd/pul)-hydrolyzing enzymes from glycosyl hydrolase 13 family (gh-13), npde exhibits a unique catalytic preference for longer malto-oligosaccharides (>g8), performing hydrolysis without the transgylcosylation or cd-hydrolyzing activities of other gh-13 e ... | 2010 | 19768689 |
| raman spectroscopic analysis of a desert cyanobacterium nostoc sp. in response to uvb radiation. | cyanobacteria are capable of tolerating environmental extremes. to survive in extreme environments, cyanobacteria have developed the capability to adapt to a variety of stresses. for example, cyanobacteria have adopted a number of strategies with which to survive uv stress, including expression of uv-screening pigments and antioxidant systems. we have previously shown that several antioxidants are significantly expressed in nostoc sp. by uvb irradiation. we report here that the content of uv-res ... | 2010 | 21087158 |
| anabaena sp. strain pcc 7120 conr contains a lytr-cpsa-psr domain, is developmentally regulated, and is essential for diazotrophic growth and heterocyst morphogenesis. | the conr (all0187) gene of the filamentous cyanobacterium anabaena (nostoc) sp. strain pcc 7120 is predicted to be part of a family of proteins that contain the lytr-cpsa-psr domain associated with septum formation and cell wall maintenance. the conr gene was originally misannotated as a transcription regulator. northern rna blot analysis showed that conr expression was upregulated 8 h after nitrogen step-down. fluorescence microscopy of a p(conr)-gfp reporter strain revealed increased gfp fluor ... | 2010 | 21088107 |
| hydrogen production and metal-dye bioremoval by a nostoc linckia strain isolated from textile mill oxidation pond. | biohydrogen production by nostoc linckia ha-46, isolated from a textile-industry oxidation-pond was studied by varying light/dark period, ph, temperature and ratio of carbon-dioxide and argon in the gas-mixture. hydrogen production rates were maximum under 18 h of light and 6 h of darkness, ph 8.0, 31°c, a co(2):ar ratio 2:10. hydrogen production of the strain acclimatized to 20 mg/l of chromium/cobalt and 100 mg/l of reactive red 198/crystal violet dye studied in n-supplemented/deficient medium ... | 2010 | 21109423 |
| assessment of salinity-induced antioxidative defense system of diazotrophic cyanobacterium nostoc muscorum. | the present study examines the salinity-induced oxidative damage and differential response of enzymatic and non-enzymatic antioxidants of nostoc muscorum. as compared to carotenoid content which showed induction the chlorophyll and phycocyanin contents were inhibited after salt stress. acceleration of lipid peroxidation and peroxide production suggested onset of oxidative damage. the activities of all studied enzymatic antioxidants were significantly increased by salt stress with maximum inducti ... | 2010 | 21124054 |
| exposure of the cyanobacterium nostoc muscorum from portuguese rice fields to molinate (ordram(®)): effects on the antioxidant system and fatty acid profile. | herbicide contamination of aquatic ecosystems is a serious global environmental concern. several herbicides enhance the intracellular formation of reactive oxygen species, and can lead to the damage of macromolecules and to a decrease of oxidant defenses in a wide range of non-target microorganisms including cyanobacteria. the effects of molinate (a thiocarbamate herbicide used for controlling grassy weeds in rice fields) on the activities of antioxidant enzymes such as superoxide dismutase, cat ... | 2010 | 21216347 |
| cytotoxicity and secondary metabolites production in terrestrial nostoc strains, originating from different climatic/geographic regions and habitats: is their cytotoxicity environmentally dependent? | extensive selection of cyanobacterial strains (82 isolates) belonging to the genus nostoc, isolated from different climatic regions and habitats, were screened for both their secondary metabolite content and their cytotoxic effects to mammalian cell lines. the overall occurrence of cytotoxicity was found to be 33%, which corresponds with previously published data. however, the frequency differs significantly among strains, which originate from different climatic regions and microsites (particula ... | 2010 | 20082446 |
| post-translational modifications of integral membrane proteins resolved by top-down fourier transform mass spectrometry with collisionally activated dissociation. | integral membrane proteins remain a challenge to proteomics because they contain domains with physicochemical properties poorly suited to today's bottom-up protocols. these transmembrane regions may potentially contain post-translational modifications of functional significance, and thus development of protocols for improved coverage in these domains is important. one way to achieve this goal is by using top-down mass spectrometry whereby the intact protein is subjected to mass spectrometry and ... | 2010 | 20093275 |
| signature proteins for the major clades of cyanobacteria. | the phylogeny and taxonomy of cyanobacteria is currently poorly understood due to paucity of reliable markers for identification and circumscription of its major clades. | 2010 | 20100331 |
| complementary uv-absorption of mycosporine-like amino acids and scytonemin is responsible for the uv-insensitivity of photosynthesis in nostoc flagelliforme. | mycosporine-like amino acids (maas) and scytonemin are uv-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. natural colonies of the uv-insensitive nostoc flagelliforme were found to be especially rich in maas (32.1 mg g dw(-1)), concentrated in the glycan sheath together with scytonemin. maas are present in the form of oligosaccharide-linked molecules. photosystem ii activity, measured using pam fluorescence and oxygen evolution, ... | 2010 | 20161974 |
| molecular mechanisms of microcystin toxicity in animal cells. | microcystins (mc) are potent hepatotoxins produced by the cyanobacteria of the genera planktothrix, microcystis, aphanizomenon, nostoc and anabaena. these cyclic heptapeptides have strong affinity to serine/threonine protein phosphatases (pps) thereby acting as an inhibitor of this group of enzymes. through this interaction a cascade of events responsible for the mc cytotoxic and genotoxic effects in animal cells may take place. moreover mc induces oxidative stress in animal cells and together w ... | 2010 | 20162015 |
| nostotrebin 6, a bis(cyclopentenedione) with cholinesterase inhibitory activity isolated from nostoc sp. str. lukesová 27/97. | nostotrebin 6, a new polyphenolic compound with a fully substituted 2,2'-bis(cyclopent-4-en-1,3-dione) skeleton, was isolated from a methanolic extract of the cyanobacterial strain nostoc sp. str. lukesová 27/97. the structure of this compound was determined using x-ray crystallography and further supported by nmr, ir spectroscopy, and ms. nostotrebin 6 is an s-parabolic i-parabolic noncompetitive inhibitor of acetylcholinesterase (ic(50) = 5.5 microm) and an s-parabolic i-parabolic mixed inhibi ... | 2010 | 20233015 |
| design and characterization of molecular tools for a synthetic biology approach towards developing cyanobacterial biotechnology. | cyanobacteria are suitable for sustainable, solar-powered biotechnological applications. synthetic biology connects biology with computational design and an engineering perspective, but requires efficient tools and information about the function of biological parts and systems. to enable the development of cyanobacterial synthetic biology, several molecular tools were developed and characterized: (i) a broad-host-range biobrick shuttle vector, ppmqak1, was constructed and confirmed to replicate ... | 2010 | 20236988 |
| bacterial diversity, pigments and nitrogen fixation of biological desert crusts from the sultanate of oman. | biological desert crusts are relatively common in the arid deserts of the sultanate of oman; however, little is known about their microbial community composition and role in soil fertilization. we compared three crusts from geographically different locations for their soil texture, bacterial community structure, pigment composition and nitrogenase activity. the crusts were growing on alkaline (ph 7.6-8.7) loamy sand and silty loam soils. microscopically, microcoleus vaginatus was the most abunda ... | 2010 | 20298501 |
| exploiting cyanobacterial p450 pathways. | cytochrome p450s are hemoprotein oxygenases involved in natural product synthetic pathways. cyanobacteria are oxygenic photosynthetic microorganisms and are considered a rich source of natural products, and are now known to harbour p450s. a variety of cyanobacterial species have been found to contain multiple copies of p450s in their genomes, and over 100 have been predicted. interestingly, some are membrane-bound as in eukaryotes, as opposed to cytoplasmic in bacteria. furthermore, they can com ... | 2010 | 20299274 |
| two alternative starter modules for the non-ribosomal biosynthesis of specific anabaenopeptin variants in anabaena (cyanobacteria). | anabaenopeptins are a diverse family of cyclic hexapeptide protease inhibitors produced by cyanobacteria that contain a conserved ureido bond and d-lys moiety. here we demonstrate that anabaenopeptins are assembled on a nonribosomal peptide synthetase enzyme complex encoded by a 32 kb apt gene cluster in the cyanobacterium anabaena sp. strain 90. surprisingly, the gene cluster encoded two alternative starter modules organized in separate bimodular proteins. the starter modules display high subst ... | 2010 | 20338518 |
| molecular cloning and characterization of maltooligosyltrehalose synthase gene from nostoc flagelliforme. | a genomic dna fragment encoding a putative maltooligosyltrehalose synthase (nfmts) for trehalose biosynthesis was cloned by the degenerate primer-pcr from cyanobacterium nostoc flagelliforme. the orf of nfmts was 2,799 bp in length and encoded 933 amino acid residues constituting a 106.6 kda protein. the deduced amino acid sequence of nfmts contained 4 regions highly conserved for mtss. by expression of nfmts in e. coli, it was demonstrated that the recombinant protein catalyzed the conversion o ... | 2010 | 20372031 |
| cyanobacteriochrome ccas regulates phycoerythrin accumulation in nostoc punctiforme, a group ii chromatic adapter. | responding to green and red light, certain cyanobacteria change the composition of their light-harvesting pigments, phycoerythrin (pe) and phycocyanin (pc). although this phenomenon-complementary chromatic adaptation-is well known, the green light-sensing mechanism for pe accumulation is unclear. the filamentous cyanobacterium nostoc punctiforme atcc 29133 (n. punctiforme) regulates pe synthesis in response to green and red light (group ii chromatic adaptation). we disrupted the green/red-percei ... | 2010 | 20404166 |
| cala, a cyabrb protein, binds to the upstream region of ftsz and is down-regulated in heterocysts in anabaena sp. pcc 7120. | a protein of cyabrb family of regulators, alr0946 (cala), was identified by dna affinity chromatography using dna fragments from the promoter region of ftsz in anabaena/nostoc sp. pcc 7120. electrophoretic mobility shift assays showed that the protein could bind to upstream regions of ftsz (as biotin-labeled dna fragments) and that the binding was inhibited by the same dna fragments and a fragment upstream of hetc but not by 3 fragments upstream of glna, hetr or ntca. both transcriptional fusion ... | 2010 | 20405108 |
| primary screening of the bioactivity of brackishwater cyanobacteria: toxicity of crude extracts to artemia salina larvae and paracentrotus lividus embryos. | cyanobacteria are a diverse group of gram-negative bacteria that produce an array of secondary compounds with selective bioactivity against vertebrates, invertebrates, plants, microalgae, fungi, bacteria, viruses and cell lines. the aim of this study was to assess the toxic effects of aqueous, methanolic and hexane crude extracts of benthic and picoplanktonic cyanobacteria isolated from estuarine environments, towards the nauplii of the brine shrimp artemia salina and embryos of the sea urchin p ... | 2010 | 20411110 |
| relationship between color and pigment production in two stone biofilm-forming cyanobacteria (nostoc sp. pcc 9104 and nostoc sp. pcc 9025). | previous studies have provided evidence that color measurements enable on site quantification of superficial biofilms, thereby avoiding the need for sampling. in the present study, the efficiency of color measurements to evaluate to what extent pigment production is affected by environmental parameters such as light intensity, combined nitrogen and nutrient availability, was tested with two cyanobacteria, nostoc sp. strains pcc 9104 and pcc 9025, which form biofilms on stone. both strains were a ... | 2010 | 20425659 |
| hideo iwai. interview by daniela ruffell. | 2010 | 20450913 | |
| cyanobacterial heterocysts. | many multicellular cyanobacteria produce specialized nitrogen-fixing heterocysts. during diazotrophic growth of the model organism anabaena (nostoc) sp. strain pcc 7120, a regulated developmental pattern of single heterocysts separated by about 10 to 20 photosynthetic vegetative cells is maintained along filaments. heterocyst structure and metabolic activity function together to accommodate the oxygen-sensitive process of nitrogen fixation. this article focuses on recent research on heterocyst d ... | 2010 | 20452939 |
| host selection of symbiotic cyanobacteria in 31 species of the australian cycad genus: macrozamia (zamiaceae). | the nitrogen-fixing cyanobacterium nostoc is a commonly occurring terrestrial and aquatic cyanobacterium often found in symbiosis with a wide range of plant, algal, and fungal species. we investigated the diversity of cyanobacterial species occurring within the coralloid roots of different macrozamia cycad species at diverse locations throughout australia. in all, 74 coralloid root samples were processed and 56 endosymbiotic cyanobacteria were cultured. dna was isolated from unialgal cultures an ... | 2010 | 20459320 |
| structure of cinaciguat (bay 58-2667) bound to nostoc h-nox domain reveals insights into heme-mimetic activation of the soluble guanylyl cyclase. | heme is a vital molecule for all life forms with heme being capable of assisting in catalysis, binding ligands, and undergoing redox changes. heme-related dysfunction can lead to cardiovascular diseases with the oxidation of the heme of soluble guanylyl cyclase (sgc) critically implicated in some of these cardiovascular diseases. sgc, the main nitric oxide (no) receptor, stimulates second messenger cgmp production, whereas reactive oxygen species are known to scavenge no and oxidize/inactivate t ... | 2010 | 20463019 |
| morphological and genetic diversity of symbiotic cyanobacteria from cycads. | the morphological and genetic diversity of cyanobacteria associated with cycads was examined using pcr amplification techniques and 16s rrna gene sequence analysis. eighteen symbiotic cyanobacteria were isolated from different cycad species. one of the symbiotic isolates was a species of calothrix, a genus not previously reported to form symbioses with cycadaceae family, and the remainder were nostoc spp. axenic cyanobacterial strains were compared by dna amplification using pcr with either shor ... | 2010 | 20473963 |
| 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 |
| expansion of ribosomally produced natural products: a nitrile hydratase- and nif11-related precursor family. | a new family of natural products has been described in which cysteine, serine and threonine from ribosomally-produced peptides are converted to thiazoles, oxazoles and methyloxazoles, respectively. these metabolites and their biosynthetic gene clusters are now referred to as thiazole/oxazole-modified microcins (tomm). as exemplified by microcin b17 and streptolysin s, tomm precursors contain an n-terminal leader sequence and c-terminal core peptide. the leader sequence contains binding sites for ... | 2010 | 20500830 |
| 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 |
| 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 |
| use of protein trans-splicing to produce active and segmentally (2)h, (15)n labeled mannuronan c5-epimerase alge4. | alginate epimerases are large multidomain proteins capable of epimerising c5 on beta-d-mannuronic acid (m) turning it into alpha-l-guluronic acid (g) in a polymeric alginate. azotobacter vinelandii secretes a family of seven epimerases, each of which is capable of producing alginates with characteristic g distribution patterns. all seven epimerases consist of two types of modules, denoted a and r, in varying numbers. attempts to study these enzymes with solution-state nmr are hampered by their s ... | 2010 | 20552686 |
| 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 |
| a novel cyanobacterial nostocyclopeptide is a potent antitoxin against microcystins. | cyanobacterial hepatotoxins (microcystins and nodularins) cause numerous animal poisonings worldwide each year and are threats to human health. however, we found that extracts from several cyanobacteria isolates failed to induce hepatotoxicity even if they contained high concentrations of the liver toxin microcystin. the antitoxic activity abolishes all morphological hallmarks of microcystin-induced apoptosis, and therefore invalidates cell-based assays of the microcystin content of bloom-formin ... | 2010 | 20575133 |
| [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 |
| the cell recognition model in chlorolichens involving a fungal lectin binding to an algal ligand can be extended to cyanolichens. | leptogium corniculatum, a cyanolichen containing nostoc as photobiont, produces and secretes arginase to culture medium containing arginine. this secreted arginase was pre-purified by affinity chromatography on beads of activated agarose to which a polygalactosylated urease, purified from evernia prunastri, was attached. arginase was eluted from the beads with 50 mm alpha-d-galactose. the eluted arginase binds preferentially to the cell surface of nostoc isolated from this lichen thallus, althou ... | 2010 | 20636904 |
| occurrence of brackish water phytoplankton species at a closed coral reef in nansha islands, south china sea. | the phytoplankton assemblage of zhubi reef, a closed coral reef in nansha islands (south china sea, scs) was studied in june 2007. a total of 92 species belonging to 53 genera and four phyla have been identified. the dominant taxa in the lagoon were the diatom chaetoceros and cyanobacteria nostoc and microcystis, while in reef flats were cyanobacteria trichodesmium erythraeum, dinoflagellates gymnodinium and prorocentrum. the species richness and diversity were consistently lower in the lagoon t ... | 2010 | 20656304 |
| synthesis, properties, and applications of diazotrifluropropanoyl-containing photoactive analogs of farnesyl diphosphate containing modified linkages for enhanced stability. | photoactive analogs of farnesyl diphosphate (fpp) are useful probes in studies of enzymes that employ this molecule as a substrate. here, we describe the preparation and properties of two new fpp analogs that contain diazotrifluoropropanoyl photophores linked to geranyl diphosphate via amide or ester linkages. the amide-linked analog (3) was synthesized in 32p-labeled form from geraniol in seven steps. experiments with saccharomyces cerevisiae protein farnesyltransferase (scpftase) showed that 3 ... | 2010 | 19954434 |
| characterization of a microcystin and detection of microcystin synthetase genes from a brazilian isolate of nostoc. | a nostocalean nitrogen-fixing cyanobacterium isolated from an eutrophic freshwater reservoir located in piracicaba, são paulo, brazil, was evaluated for the production of hepatotoxic cyclic heptapeptides, microcystins. morphologically this new cyanobacterium strain appears closest to nostoc, however, in the phylogenetic analysis of 16s rrna gene it falls into a highly stable cluster distantly only related to the typical nostoc cluster. extracts of nostoc sp. cena88 cultured cells, investigated u ... | 2010 | 20003912 |
| cala, a cyanobacterial abrb protein, interacts with the upstream region of hypc and acts as a repressor of its transcription in the cyanobacterium nostoc sp. strain pcc 7120. | the filamentous, heterocystous, nitrogen-fixing cyanobacterium nostoc sp. strain pcc 7120 may contain, depending on growth conditions, up to two hydrogenases directly involved in hydrogen metabolism. hypc is one out of at least seven auxiliary gene products required for synthesis of a functional hydrogenase, specifically involved in the maturation of the large subunit. in this study we present a protein, cala (alr0946 in the genome), belonging to the transcription regulator family abrb, which in ... | 2010 | 20023111 |
| excitation energy transfer to photosystem i in filaments and heterocysts of nostoc punctiforme. | cyanobacteria adapt to varying light conditions by controlling the amount of excitation energy to the photosystems. on the minute time scale this leads to redirection of the excitation energy, usually referred to as state transitions, which involves movement of the phycobilisomes. we have studied short-term light adaptation in isolated heterocysts and intact filaments from the cyanobacterium nostoc punctiforme atcc 29133. in n. punctiforme vegetative cells differentiate into heterocysts where ni ... | 2010 | 20036211 |
| detection of the neurotoxin bmaa within cyanobacteria isolated from freshwater in china. | the cyanobacterial neurotoxin, beta-n-methylamino-l-alanine (bmaa), has been suggested as an important environmental factor for neurodegenerative disease such as amyotrophic lateral sclerosis- parkinsonism dementia complex (als/pdc) in guam. bmaa was detected within the majority of cyanobacterial isolates surveyed in both free and symbiotic cyanobacteria, living in freshwater as well as marine environments. in this study, we report two methods using liquid chromatography-electrospray ionization- ... | 2010 | 19822166 |
| 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 |
| 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 |
| 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 |
| 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 |
| multiple roles of soluble sugars in the establishment of gunnera-nostoc endosymbiosis. | gunnera plants have the unique ability to form endosymbioses with n(2)-fixing cyanobacteria, primarily nostoc. cyanobacteria enter gunnera through transiently active mucilage-secreting glands on stems. we took advantage of the nitrogen (n)-limitation-induced gland development in gunnera manicata to identify factors that may enable plant tissue to attract and maintain cyanobacteria colonies. cortical cells in stems of n-stressed gunnera plants were found to accumulate a copious amount of starch, ... | 2010 | 20833727 |
| protein immobilization on liposomes and lipid-coated nanoparticles by protein trans-splicing. | a plethora of methods exist to link proteins to surfaces in order to generate functionalized materials. however, general tools that lead to functional immobilization of recombinantly expressed proteins on membranes such as liposomes or lipid-coated nanoparticles are rare. here we present an approach that takes advantage of a double-palmitoylated peptide that mediates stable membrane anchoring in combination with protein trans-splicing for efficient immobilization of recombinant proteins fused to ... | 2010 | 20862726 |
| computational analysis of lexa regulons in cyanobacteria. | the transcription factor lexa plays an important role in the sos response in escherichia coli and many other bacterial species studied. although the lexa gene is encoded in almost every bacterial group with a wide range of evolutionary distances, its precise functions in each group/species are largely unknown. more recently, it has been shown that lexa genes in two cyanobacterial genomes nostoc sp. pcc 7120 and synechocystis sp. pcc 6803 might have distinct functions other than the regulation of ... | 2010 | 20920248 |
| effect of psts sub-units or pknd deficiency on the survival of mycobacterium tuberculosis. | the membrane-associated phosphate-specific transporter (pst) complex is composed of four different proteins: psts, pstc, psta and pstb. the psts component detects and binds pi with high affinity; the psta and pstc form transmembrane pores for pi entry, while pstb provides energy through atp hydrolysis. in the mycobacterium tuberculosis genome, four different gene clusters encode three psts, and two of each of the other sub-units. we used rt-pcr to show that these clusters represent at least thre ... | 2010 | 20933472 |
| differential roles of alkaline/neutral invertases in nostoc sp. pcc 7120: inv-b isoform is essential for diazotrophic growth. | the presence of two alkaline/neutral invertases (inv-a and inv-b) in the filaments of nostoc (also named anabaena) sp. strain pcc 7120 and the involvement of sucrose metabolism in nitrogen fixation led us to investigate the physiological function of those isoforms in cells growing under different nitrogen sources. the highest expression level of each encoding gene was obtained in the presence of ammonium. these results were paralleled by polypeptide and enzyme activity level. in cells of n(2)-fi ... | 2010 | 20938678 |
| biological dinitrogen fixation by selected soil cyanobacteria as affected by strain origin, morphotype, and light conditions. | the potential for n(2) fixation by heterocystous cyanobacteria isolated from soils of different geographical areas was determined as nitrogenase activity (na) using the acetylene reduction assay. morphology of cyanobacteria had the largest influence on na determined under light conditions. na was generally higher in species lacking thick slime sheaths. the highest value (1446 nmol/h c(2)h(4) per g fresh biomass) was found in the strain of branched cyanobacterium hassalia (a has1) from the polar ... | 2010 | 20941582 |
| allelopathic effects of water hyacinth [eichhornia crassipes]. | eichhornia crassipes (mart) solms is an invasive weed known to out-compete native plants and negatively affect microbes including phytoplankton. the spread and population density of e. crassipes will be favored by global warming. the aim here was to identify compounds that underlie the effects on microbes. the entire plant of e. crassipes was collected from el zomor canal, river nile (egypt), washed clean, then air dried. plant tissue was extracted three times with methanol and fractionated by t ... | 2010 | 20949048 |
| poly-β-hydroxybutyrate accumulation in cyanobacteria under photoautotrophy. | poly-β-hydroxybutyrate (phb) is a biodegradable and biocompatible polymer that has immense potential in the field of environmental, agricultural and biomedical sciences. an alternative host system has been explored in this study for low-cost production. examination of 25 cyanobacterial species from 19 different genera for photoautrophic production of polyhydroxyalkanoates (phas) under batch culture demonstrated that 20 species were poly-β-hydroxybutyrate (phb) accumulators, while others were fou ... | 2010 | 20949541 |
| comparative toxicity of bentazon and molinate on growth, photosynthetic pigments, photosynthesis, and respiration of the portuguese ricefield cyanobacterium nostoc muscorum. | bentazon and molinate are selective herbicides recommended for integrated weed management in rice. their toxicity on growth and some biochemical and physiological parameters of nostoc muscorum, an abundant cyanobacterium in portuguese rice fields, was evaluated under laboratory conditions during time- and concentration-dependent exposure for 72 h. results showed that toxic concentrations (0.75-2 mm) of both herbicides have pleiotropic effects on the cyanobacterium. molinate was more toxic than b ... | 2010 | 19319991 |
| enlarging clinical spectrum of fals with tardbp gene mutations: s393l variant in an italian family showing phenotypic variability and relevance for genetic counselling. | the present study was aimed to enlarge the italian als sample analysed for tardbp gene mutations. | 2010 | 19714537 |
| a novel alpha-amylase from the cyanobacterium nostoc sp. pcc 7119. | little information is yet available on the alpha-amylases of cyanobacteria. here, the presence of an alpha-amylase in the cyanobacterium nostoc sp. pcc 7119 is first demonstrated. a gene (amy1) encoding a cytoplasmic alpha-amylase (amy1) protein has been identified, cloned, and overexpressed in escherichia coli cells. the recombinant protein is a 56.7-kda monomer, which has been purified to electrophoretic homogeneity by affinity chromatography. the substrate specificity and end product analyses ... | 2010 | 19756583 |
| accumulation of exopolysaccharides in liquid suspension culture of nostoc flagelliforme cells. | the liquid suspension culture of dissociated nostoc flagelliforme cells was investigated. it was found that the growth rate of n. flagelliforme cells and the accumulation of exopolysaccharides (eps) increased prominently when nano(3) and kh(2)po(4) were added in the liquid bg-11culture medium though phosphate had little effect on eps yield for specific mass of cells. n. flagelliforme cells grew well at 25 degrees c and neutral ph, however, a lower or higher temperature and weak alkaline can prom ... | 2010 | 19018481 |
| purification and crystallization of the cyanobacterial cytochrome b6f complex. | the cytochrome b6f complex from the filamentous cyanobacteria (mastigocladus laminosus, nostoc sp. pcc 7120) and spinach chloroplasts has been purified as a homo-dimer. electrospray ionization mass spectroscopy showed the monomer to contain eight and nine subunits, respectively, and dimeric masses of 217.1, 214.2, and 286.5 kda for m. laminosus, nostoc, and the complex from spinach. the core subunits containing or interacting with redox-active prosthetic groups are peta (cytochrome f), b (cytoch ... | 2011 | 20960122 |
| purification of plastocyanin and cytochrome c6 from plants, green algae, and cyanobacteria. | plastocyanin and cytochrome c6 are widely distributed over the oxygen-evolving photosynthetic organisms. the two proteins are functionally equivalent, but strongly differ in their global electrostatic charge. in fact, they are acidic in eukaryotes, but either neutral or basic in cyanobacteria. such a difference in their electrostatic features is a critical factor in designing the purification procedure, which must thus be modified and adapted accordingly. this chapter reports the methods for pro ... | 2011 | 20960123 |
| the apoptosis-inducing activity towards leukemia and lymphoma cells in a cyanobacterial culture collection is not associated with mouse bioassay toxicity. | cyanobacteria (83 strains and seven natural populations) were screened for content of apoptosis (cell death)-inducing activity towards neoplastic cells of the immune (jurkat acute t-cell lymphoma) and hematopoetic (acute myelogenic leukemia) lineage. apoptogenic activity was frequent, even in strains cultured for decades, and was unrelated to whether the cyanobacteria had been collected from polar, temperate, or tropic environments. the activity was more abundant in the genera anabaena and micro ... | 2011 | 20689978 |
| life cycle as a stable trait in the evaluation of diversity of nostoc from biofilms in rivers. | the diversity within the genus nostoc is still controversial and more studies are needed to clarify its heterogeneity. macroscopic species have been extensively studied and discussed; however, the microscopic forms of the genus, especially those from running waters, are poorly known and likely represented by many more species than currently described. nostoc isolates from biofilms of two spanish calcareous rivers were characterized comparing the morphology and life cycle in two culture media wit ... | 2011 | 21223333 |
| efficient functional analysis system for cyanobacterial or plant cytochromes p450 involved in sesquiterpene biosynthesis. | tractable plasmids (pac-mv-based plasmids) for escherichia coli were constructed, which carried a mevalonate-utilizing gene cluster, towards an efficient functional analysis of cytochromes p450 involved in sesquiterpene biosynthesis. they included genes coding for a series of redox partners that transfer the electrons from nad(p)h to a p450 protein. the redox partners used were ferredoxin reductases (cama and nsred) and ferredoxins (camb and nsfer), which are derived from pseudomonas putida and ... | 2011 | 21229242 |
| modification of transmembrane and gpi-anchored proteins on living cells by efficient protein trans-splicing using the npu dnae intein. | the naturally split npu dnae intein can be used for ligation of an exogenous polypeptide to membrane proteins on living cells. no reducing agents or other factors are required. the approach is rapid and virtually traceless, because the intein removes itself during the reaction. | 2011 | 21234473 |
| the morphogene amic2 is pivotal for multicellular development in the cyanobacterium nostoc punctiforme. | filamentous cyanobacteria of the order nostocales are primordial multicellular organisms, a property widely considered unique to eukaryotes. their filaments are composed of hundreds of mutually dependent vegetative cells and regularly spaced n(2)-fixing heterocysts, exchanging metabolites and signalling molecules. furthermore, they may differentiate specialized spore-like cells and motile filaments. however, the structural basis for cellular communication within the filament remained elusive. he ... | 2011 | 21244533 |
| metabolic adaptations in a h2 producing heterocyst-forming cyanobacterium: potentials and implications for biological engineering. | nostoc punctiforme atcc 29133 is a photoautotrophic cyanobacterium with the ability to fix atmospheric nitrogen and photoproduce hydrogen through the enzyme nitrogenase. the h(2) produced is reoxidized by an uptake hydrogenase. inactivation of the uptake hydrogenase in n. punctiforme leads to increased h(2) release but unchanged rates of n(2) fixation, indicating redirected metabolism. system-wide understanding of the mechanisms of this metabolic redirection was obtained using complementary quan ... | 2011 | 21284387 |
| characterization of complementary chromatic adaptation in gloeotrichia utex 583 and identification of a transposon-like insertion in the cpeba operon. | many cyanobacteria are able to alter the pigment composition of the phycobilisome in a process called complementary chromatic adaptation (cca). the regulatory mechanisms of cca have been identified in fremyella diplosiphon, which regulates both phycoerythrin and phycocyanin levels, and nostoc punctiforme, which regulates only phycoerythrin production. recent studies show that these species use different regulatory proteins for cca. we chose to study the cca response of gloeotrichia utex 583 in a ... | 2011 | 21288891 |
| influence of temperature and uvr on photosynthesis and morphology of four species of cyanobacteria. | during the late austral spring of 2009 we carried out experiments (4days of duration) with four cyanobacteria species, anabaena sp., nostoc sp., arthrospira platensis and microcystis sp., to assess the combined effects of temperature and solar radiation on photosynthesis performance and morphology. two experimental temperatures (18°c and 23°c, simulating a 5°c increase under a scenario of climate change) and three radiation treatments (by using different filters/materials) were implemented: (i) ... | 2011 | 21296589 |
| the sige gene is required for normal expression of heterocyst-specific genes in anabaena sp. strain pcc 7120. | the filamentous cyanobacterium anabaena (nostoc) sp. strain pcc 7120 produces specialized cells for nitrogen fixation called heterocysts. previous work showed that the group 2 sigma factor sige (alr4249; previously called sigf) is upregulated in differentiating heterocysts 16 h after nitrogen step-down. we now show that the sige gene is required for normal heterocyst development and normal expression levels of several heterocyst-specific genes. mobility shift assays showed that the transcription ... | 2011 | 21317330 |
| detection of formate, rather than carbon monoxide, as the stoichiometric coproduct in conversion of fatty aldehydes to alkanes by a cyanobacterial aldehyde decarbonylase. | the second of two reactions in a recently discovered pathway through which saturated fatty acids are converted to alkanes (and unsaturated fatty acids to alkenes) in cyanobacteria entails scission of the c1-c2 bond of a fatty aldehyde intermediate by the enzyme aldehyde decarbonylase (ad), a ferritin-like protein with a dinuclear metal cofactor of unknown composition. we tested for and failed to detect carbon monoxide (co), the proposed c1-derived coproduct of alkane synthesis, following the in ... | 2011 | 21341652 |
| effect of crowding on the electron transfer process from plastocyanin and cytochrome c6 to photosystem i: a comparative study from cyanobacteria to green algae. | plastocyanin and cytochrome c(6), the alternate donor proteins to photosystem i, can be acidic, neutral or basic; the role of electrostatics in their interaction with photosystem i vary accordingly for cyanobacteria, algae and plants. the effect of different crowding agents on the kinetics of the reaction between plastocyanin or cytochrome c(6) and photosystem i from three different cyanobacteria, synechocystis pcc 6803, nostoc pcc 7119 and arthrospira maxima, and a green alga, monoraphidium bra ... | 2011 | 21344311 |
| iron starvation-induced proteomic changes in anabaena (nostoc) sp. pcc 7120: exploring survival strategy. | this study provides first-hand proteomic data on the survival strategy of anabaena sp. pcc 7120 when subjected to long-term iron-starvation conditions. 2d-gel electrophoresis followed by maldi-tof/ms analysis of iron-deficient anabaena revealed significant and reproducible alterations in ten proteins, of which six are associated with photosynthesis and respiration, three with the antioxidative defense system, and the last, hypothetical protein all1861, conceivably connected with iron homeostasis ... | 2011 | 21364295 |
| response of diazotrophic cyanobacterium nostoc carneum under pesticide and uv-b stress. | a study was under taken, under controlled laboratory conditions, to investigate the influence of non-ionizing radiation (uv-b) and an organochlorine pesticide on the growth, photosynthetic pigments, protein content and dcpip photoreduction of a cyanobacterium nostoc carneum. test algae was isolated from rice field soils of sambalpur, western orissa, india and grown in nitrogen free bg 11 culture medium. culture of algae from log phase of growth was treated with 5 pp m of the insecticide, endodha ... | 2011 | 21388655 |
| dna-based prenatal diagnosis of plectin-deficient epidermolysis bullosa simplex associated with pyloric atresia. | mutations in the plectin gene (plec) generally lead to epidermolysis bullosa simplex (ebs) associated with muscular dystrophy. it has been recently demonstrated that plec mutations can also cause a different clinical subtype, ebs associated with pyloric atresia (ebs-pa), which shows early lethality. prenatal diagnosis (pnd) of ebs-pa using mutation screening of plec has not been described. | 2011 | 21413955 |
| overexpression of pkne blocks heterocyst development in anabaena sp. strain pcc 7120. | the upstream intergenic regions for each of four genes encoding ser/thr kinases, all2334, pkne (alr3732), all4668, and all4838, were fused to a gfpmut2 reporter gene to determine their expression during heterocyst development in the cyanobacterium anabaena (nostoc) sp. strain pcc 7120. p(pkne)-gfp was upregulated after nitrogen step-down and showed strong expression in differentiating cells. developmental regulation of pkne required a 118-bp upstream region and was abolished in a hetr mutant. a ... | 2011 | 21421755 |
| conversion of fatty aldehydes to alka(e)nes and formate by a cyanobacterial aldehyde decarbonylase: cryptic redox by an unusual dimetal oxygenase. | cyanobacterial aldehyde decarbonylase (ad) catalyzes conversion of fatty aldehydes (r-cho) to alka(e)nes (r-h) and formate. curiously, although this reaction appears to be redox-neutral and formally hydrolytic, ad has a ferritin-like protein architecture and a carboxylate-bridged dimetal cofactor that are both structurally similar to those found in di-iron oxidases and oxygenases. in addition, the in vitro activity of the ad from nostoc punctiforme (np) was shown to require a reducing system sim ... | 2011 | 21462983 |