Publications

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
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
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
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
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
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
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
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
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
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
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
hideo iwai. interview by daniela ruffell.		2010	20450913
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
sequence based data supports a single nostoc strain in individual coralloid roots of cycads.	the genetic diversity of cyanobacteria associated with cycads was examined using the trna(leu) (uaa) intron as a genetic marker. coralloid roots of both natural populations of the cycad macrozamia riedlei (fischer ex gaudichaud-beaupré) c.a. gardner growing in perth, australia and cycads growing in greenhouses, also in perth, were used and their respective cyanobionts analyzed. several nostoc strains were found to be involved in this symbiosis, both in natural populations and greenhouse-originat ...	2004	19712296
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
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
gated electron transfer of cytochrome c6 at biomimetic interfaces: a time-resolved serr study.	the electron shuttle heme protein cyt-c(6) from the photosynthetic cyanobacterium nostoc sp. pcc 7119 was immobilized on nanostructured ag electrodes coated with sams that mimic different possible interactions with its natural reaction partner psi. the structure, redox potential, and electron-transfer dynamics of the sam-cyt-c(6) complexes were investigated by tr-serr spectroelectrochemistry. it is shown that the heterogeneous electron-transfer process is gated both in electrostatic and hydropho ...	2009	19690710
microcystin producing cyanobacterium nostoc sp. bhu001 from a pond in india.	the cyanobacterium nostoc sp. bhu001 is a new isolate from a pond in india. the cyanobacterium produces more than ten peptides including five microcystin (mc) variants, mc-lr, -wr, -ar, -la and methylated mc-lr, and a new peptide similar to cyanopeptolin. total mc content determined by elisa was 25.2 microg g(-1) dry wt of the cyanobacterium, dominated by mc-lr (54%). this is the first report of mc producing nostoc strain from india.	2009	19673105
unique carotenoids in the terrestrial cyanobacterium nostoc commune nies-24: 2-hydroxymyxol 2'-fucoside, nostoxanthin and canthaxanthin.	cyanobacteria produce some carotenoids. we identified the molecular structures, including the stereochemistry, of all the carotenoids in the terrestrial cyanobacterium, nostoc commune nies-24 (iam m-13). the major carotenoid was beta-carotene. its hydroxyl derivatives were (3r)-beta-cryptoxanthin, (3r,3'r)-zeaxanthin, (2r,3r,3'r)-caloxanthin, and (2r,3r,2'r,3'r)-nostoxanthin, and its keto derivatives were echinenone and canthaxanthin. the unique myxol glycosides were (3r,2's)-myxol 2'-fucoside a ...	2009	19669835
analysis of current and alternative phenol based rna extraction methodologies for cyanobacteria.	the validity and reproducibility of gene expression studies depend on the quality of extracted rna and the degree of genomic dna contamination. cyanobacteria are gram-negative prokaryotes that synthesize chlorophyll a and carry out photosynthetic water oxidation. these organisms possess an extended array of secondary metabolites that impair cell lysis, presenting particular challenges when it comes to nucleic acid isolation. therefore, we used the nhm5 strain of nostoc punctiforme atcc 29133 to ...	2009	19660145
site-specific two-color protein labeling for fret studies using split inteins.	fluorescence resonance energy transfer (fret) is an ideal tool for studying protein conformational changes and dynamics. strategies to specifically label proteins with multiple colors at structurally important sites, a prerequisite for such studies, however, need to be devised on a protein-by-protein basis. here we describe a simple yet widely applicable two-color site-specific protein labeling method utilizing npu dnae split intein.	2009	19645470
nmr resonance assignment of dnae intein from nostoc punctiforme.	dnae intein from nostoc punctiforme (npu) is one of naturally occurring split inteins, which has robust protein splicing activity. highly efficient trans-splicing activity of npudnae intein could widen various biotechnological applications. however, structural basis of the efficient protein splicing activity is poorly understood. as a first step toward better understanding of protein trans-splicing mechanism, we present the backbone and side-chain resonance assignments of a single chain variant ...	2009	19636943
assessment of sampling strategies for gas chromatography-mass spectrometry (gc-ms) based metabolomics of cyanobacteria.	metabolomics is the comprehensive analysis of the small molecules that compose an organism's metabolism. the main limiting step in microbial metabolomics is the requirement for fast and efficient separation of microbes from the culture medium under conditions in which metabolism is rapidly halted. in this article we compare three different sampling strategies, quenching, filtering, and centrifugation, for arresting the metabolic activities of two morphologically diverse cyanobacteria, the unicel ...	2009	19631594
a comparative genomics approach to understanding the biosynthesis of the sunscreen scytonemin in cyanobacteria.	the extracellular sunscreen scytonemin is the most common and widespread indole-alkaloid among cyanobacteria. previous research using the cyanobacterium nostoc punctiforme atcc 29133 revealed a unique 18-gene cluster (npr1276 to npr1259 in the n. punctiforme genome) involved in the biosynthesis of scytonemin. we provide further genomic characterization of these genes in n. punctiforme and extend it to homologous regions in other cyanobacteria.	2009	19630972
on the contributions of diffusion and thermal activation to electron transfer between phormidium laminosum plastocyanin and cytochrome f: brownian dynamics simulations with explicit modeling of nonpolar desolvation interactions and electron transfer events.	the factors that determine the extent to which diffusion and thermal activation processes govern electron transfer (et) between proteins are debated. the process of et between plastocyanin (pc) and cytochrome f (cytf) from the cyanobacterium phormidium laminosum was initially thought to be diffusion-controlled but later was found to be under activation control (schlarb-ridley, b. g.; et al. biochemistry 2005, 44, 6232). here we describe brownian dynamics simulations of the diffusional associatio ...	2009	19518050
alteration of the gastrointestinal microbiota of mice by edible blue-green algae.	to characterize the effect of edible blue-green algae (cyanobacteria) on the gastrointestinal microbiota of mice.	2009	19486425
a versatile photoactivatable probe designed to label the diphosphate binding site of farnesyl diphosphate utilizing enzymes.	farnesyl diphosphate (fpp) is a substrate for a diverse number of enzymes found in nature. photoactive analogues of isoprenoid diphosphates containing either benzophenone, diazotrifluoropropionate or azide groups have been useful for studying both the enzymes that synthesize fpp as well as those that employ fpp as a substrate. here we describe the synthesis and properties of a new class of fpp analogues that links an unmodified farnesyl group to a diphosphate mimic containing a photoactive benzo ...	2009	19447628
microcystin production in the tripartite cyanolichen peltigera leucophlebia.	we show that the cyanobacterial symbionts of a tripartite cyanolichen can produce hepatotoxic microcystins in situ. microcystins were detected with high-performance liquid chromatography mass spectrometry both from cephalodia of the tripartite cyanolichen peltigera leucophlebia and from a symbiotic nostoc strain isolated from the same lichen specimen. genetic identities of symbiotic nostoc strains were studied by amplifying and sequencing the 16s rrna gene. also, the presence of the microcystin ...	2009	19445594
water-stress induced trehalose accumulation and control of trehalase in the cyanobacterium nostoc punctiforme iam m-15.	we investigated the biochemical properties of the enzymes involved in trehalose metabolism in the cyanobacterium nostoc punctiforme strain iam m-15 to elucidate the mechanism of trehalose accumulation in response to desiccation and salt stress. there was no detectable trehalose in fully hydrated n. punctiforme cells; however, these cells accumulated trehalose upon desiccation. moreover, nacl treatment also induced trehalose accumulation. the three genes for trehalose metabolism, trez (maltooligo ...	2009	19436130
gene expression patterns associated with the biosynthesis of the sunscreen scytonemin in nostoc punctiforme atcc 29133 in response to uva radiation.	under exposure to uv radiation, some cyanobacteria synthesize sunscreen compounds. scytonemin is a heterocyclic indole-alkaloid sunscreen, the synthesis of which is induced upon exposure to uva (long-wavelength uv) radiation. we previously identified and characterized an 18-gene cluster associated with scytonemin biosynthesis in the cyanobacterium nostoc punctiforme atcc 29133; we now report on the expression response of these genes to a step-up shift in uva exposure. using quantitative pcr on c ...	2009	19429608
diversity of 23s rrna genes within individual prokaryotic genomes.	the concept of ribosomal constraints on rrna genes is deduced primarily based on the comparison of consensus rrna sequences between closely related species, but recent advances in whole-genome sequencing allow evaluation of this concept within organisms with multiple rrna operons.	2009	19415112
hypocholesterolemic effect of nostoc commune var. sphaeroides kützing, an edible blue-green alga.	intake of an edible blue-green alga nostoc commune var. sphaeroides kützing (n. commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect have not been elucidated.	2009	19404563
electron transfer protein complexes in the thylakoid membranes of heterocysts from the cyanobacterium nostoc punctiforme.	filamentous, heterocystous cyanobacteria are capable of nitrogen fixation and photoautotrophic growth. nitrogen fixation takes place in heterocysts that differentiate as a result of nitrogen starvation. heterocysts uphold a microoxic environment to avoid inactivation of nitrogenase, e.g. by downregulation of oxygenic photosynthesis. the atp and reductant requirement for the nitrogenase reaction is considered to depend on photosystem i, but little is known about the organization of energy convert ...	2009	19366613
in vivo and in vitro protein ligation by naturally occurring and engineered split dnae inteins.	protein trans-splicing by naturally occurring split dnae inteins is used for protein ligation of foreign peptide fragments. in order to widen biotechnological applications of protein trans-splicing, it is highly desirable to have split inteins with shorter c-terminal fragments, which can be chemically synthesized.	2009	19365564
endothelial cell-based methods for the detection of cyanobacterial anti-inflammatory and wound-healing promoting metabolites.	acute lung injury is accompanied by an increased endothelial chemokine production and adhesion molecule expression, which may result in an extensive neutrophil infiltration. moreover, a destruction of the alveolar epithelium and capillary endothelium may result in permeability edema. as such, the search for novel anti-inflammatory substances, able to downregulate these parameters as well as the tissue damage holds therapeutic promise. we therefore describe here the use of human endothelial cell- ...	2007	19356051
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
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
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
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
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
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
growth and periodicity of cyanobacterial bloom in a polluted pond of agra city.	periodical changes in physico-chemical properties and cyanophycean bloom in a pond ofagra city during the year 2005 and 2006 were studied. it was recorded that the pond water was polluted throughout the study period and this was closely associated with cyanobacterial bloom. during summer (march to june), the pond water was highly polluted, as it was rich in various nutrients and phosphates in particular. the ph of pond water was high with low do and this was associated with the highest peak of w ...	2008	19297980
removal of colour from textile effluent using cyanobacterial biomass.	the cyanobacterial species were isolated from fresh water pond of gura-vishnoiyan and were tested for their ability to decolourise the textile effluent. the reduction in colour of textile effluent with the use of dry biomass of cylindrospermum indicum, nostoc calcicola, calothrix weberi was comparatively observed after 2, 4 and 6 days, but maximum colour absorption was observed after 6 days. calothrix weberi was found the most effective species of cyanobacteria, which can remove the colour inten ...	2008	19295090
characterization of the hupsl promoter activity in nostoc punctiforme atcc 29133.	in cyanobacteria three enzymes are directly involved in the hydrogen metabolism; a nitrogenase that produces molecular hydrogen, h2, as a by-product of nitrogen fixation, an uptake hydrogenase that recaptures h2 and oxidize it, and a bidirectional hydrogenase that can both oxidize and produce h2.nostoc punctiforme atcc 29133 is a filamentous dinitrogen fixing cyanobacterium containing a nitrogenase and an uptake hydrogenase but no bidirectional hydrogenase. generally, little is known about the t ...	2009	19284581
diversity and transcription of proteases involved in the maturation of hydrogenases in nostoc punctiforme atcc 29133 and nostoc sp. strain pcc 7120.	the last step in the maturation process of the large subunit of [nife]-hydrogenases is a proteolytic cleavage of the c-terminal by a hydrogenase specific protease. contrary to other accessory proteins these hydrogenase proteases are believed to be specific whereby one type of hydrogenases specific protease only cleaves one type of hydrogenase. in cyanobacteria this is achieved by the gene product of either hupw or hoxw, specific for the uptake or the bidirectional hydrogenase respectively. the f ...	2009	19284580
directed biosynthesis of phytotoxic alkaloids in the cyanobacterium nostoc 78-12a.	nostocarboline, a chlorinated and n-methylated carbolinium alkaloid, displays potent and selective inhibition of photoautotrophic organisms as well as the malaria parasite plasmodium falciparum, while showing very low toxicity to bacterial and fungal pathogens, rat myoblasts and crustaceans. new derivatives of nostocarboline incorporating br, f or methyl substituents have been obtained through precursor-directed biosynthesis in nostoc 78-12a (identical to nostoc sp. atcc 43238) by feeding this c ...	2009	19263450
nitrogen fixation in mixed hylocomium splendens moss communities.	the pleurocarpus feather moss, hylocomium splendens, is one of two co-dominant moss species in boreal forest ecosystems and one of the most common mosses on earth, yet little is known regarding its capacity to host cyanobacterial associates and thus contribute total ecosystem n. in these studies, we evaluated the n-fixation potential of the h. splendens-cyanobacteria association and contrasted the n-fixation activity with that of the putative n-fixing moss-cyanobacteria association of pleurozium ...	2009	19252932
biosynthesis of a linoleic acid allylic epoxide: mechanistic comparison with its chemical synthesis and leukotriene a biosynthesis.	biosynthesis of the leukotriene a (lta) class of epoxide is a lipoxygenase-catalyzed transformation requiring a fatty acid hydroperoxide substrate containing at least three double bonds. here, we report on biosynthesis of a dienoic analog of lta epoxides via a different enzymatic mechanism. beginning with homolytic cleavage of the hydroperoxide moiety, a catalase/peroxidase-related hemoprotein from anabaena pcc 7120, which occurs in a fusion protein with a linoleic acid 9r-lipoxygenase, dehydrat ...	2009	19244216
immunolocalization of the uptake hydrogenase in the marine cyanobacterium lyngbya majuscula ccap 1446/4 and two nostoc strains.	in n(2)-fixing cyanobacteria, the reduction of n(2) to nh(3) is coupled with the production of molecular hydrogen, which is rapidly consumed by an uptake hydrogenase, an enzyme that is present in almost all diazotrophic cyanobacteria. the cellular and subcellular localization of the cyanobacterial uptake hydrogenase remains uncertain, and it is definitely strain dependent. previous studies focused mainly on heterocystous cyanobacteria and used heterologous antisera. the present work represents t ...	2009	19222582
structural basis of murein peptide specificity of a gamma-d-glutamyl-l-diamino acid endopeptidase.	the crystal structures of two homologous endopeptidases from cyanobacteria anabaena variabilis and nostoc punctiforme were determined at 1.05 and 1.60 a resolution, respectively, and contain a bacterial sh3-like domain (sh3b) and a ubiquitous cell-wall-associated nlpc/p60 (or chap) cysteine peptidase domain. the nlpc/p60 domain is a primitive, papain-like peptidase in the ca clan of cysteine peptidases with a cys126/his176/his188 catalytic triad and a conserved catalytic core. we deduced from st ...	2009	19217401
structure-function, stability, and chemical modification of the cyanobacterial cytochrome b6f complex from nostoc sp. pcc 7120.	the crystal structure of the cyanobacterial cytochrome b(6)f complex has previously been solved to 3.0-a resolution using the thermophilic mastigocladus laminosus whose genome has not been sequenced. several unicellular cyanobacteria, whose genomes have been sequenced and are tractable for mutagenesis, do not yield b(6)f complex in an intact dimeric state with significant electron transport activity. the genome of nostoc sp. pcc 7120 has been sequenced and is closer phylogenetically to m. lamino ...	2009	19189962
structure of the biliverdin radical intermediate in phycocyanobilin:ferredoxin oxidoreductase identified by high-field epr and dft.	the cyanobacterial enzyme phycocyanobilin:ferredoxin oxidoreductase (pcya) catalyzes the two-step four-electron reduction of biliverdin ixalpha to phycocyanobilin, the precursor of biliprotein chromophores found in phycobilisomes. it is known that catalysis proceeds via paramagnetic radical intermediates, but the structure of these intermediates and the transfer pathways for the four protons involved are not known. in this study, high-field electron paramagnetic resonance (epr) spectroscopy of f ...	2009	19159240
solid-phase/supercritical-fluid extraction for liquid chromatography of phenolic compounds in freshwater microalgae and selected cyanobacterial species.	in the present paper a new extraction technique based on the combination of solid-phase/supercritical-fluid extraction (spe/sfe) with subsequent reversed-phase hplc is described. the spe/sfe extractor was originally constructed from spe-cartridge incorporated into the sfe extraction cell. selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acid), hydroxybenzaldehydes (4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde) and cinnamic acid d ...	2009	19111311
preliminary survey of edaphic algae in al-hasa region, saudi arabia.	five soil samples were taken from different cultivated sites from the north villages of al-hasa. three algal groups were recorded throughout this study, bacillariophyta, cyanophyta and chlorophyta. fifty-two genera of algae were identified in all the soils sampled during this investigation. out of these, 11 genera belonged to the chlorophyta; 16 genera belong to bacillariophyta and 25 genera to cyanophyta. penniate bacillariophyta (nitzschia, gyrosigma), oscillatorid cyanophyta (osillatoria, pho ...	2007	19090128
biological control of faba bean pathogenic fungi by three cyanobacterial filtrates.	the aim of the present study is to evaluate the biological control aptitude of the cyanobacteria, anabaena subcylindrica, nostoc muscorum and oscillatoria angusta filtrates on the growth of the isolated pathogenic fungi from the different organs of faba bean. three caynobacterial (anabaena subcylindrica, nostoc muscorum and oscillatoria angusta) filtrates were prepared in different concentrations and their effects on the isolated pathogenic fungi from leaves, stems and roots of faba bean were st ...	2007	19090096
crystal structure of npun_r1517, a putative negative regulator of heterocyst differentiation from nostoc punctiforme pcc 73102.		2009	19089958
repression of proinflammatory gene expression by lipid extract of nostoc commune var sphaeroides kützing, a blue-green alga, via inhibition of nuclear factor-kappab in raw 264.7 macrophages.	we investigated whether lipid extract from a blue-green alga, n commune, modulates proinflammatory gene expression in raw 264.7 macrophages. the cells were incubated with n commune lipid extract (0-100 microg/ml) and subsequently activated by lps (100 ng/ml). quantitative real-time pcr analysis showed that mrna abundance of proinflammatory mediators, including tnf-alpha, cox-2, il-1beta, il-6, and inos, was significantly reduced by n commune lipid extract in a dose-dependent manner. secretion of ...	2008	19083393
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
isolation and characterization of the gene associated with geosmin production in cyanobacteria.	geosmin is a secondary metabolite responsible for earthy tastes and odors in potable water supplies. geosmin continues to be a challenge to water utility management regimes and remains one of the most common causes of consumer complaints, as the taste of "dirty" water may suggest a failed disinfection regime and that the water may be unsafe to drink. although cyanobacteria have been reported to be largely responsible for these taste and odor events, the answer as to how or why geosmin is produce ...	2008	19031897
novel thermostable glycosidases in the extracellular matrix of the terrestrial cyanobacterium nostoc commune.	the cyanobacterium nostoc commune is adapted to the terrestrial environment and forms a visible colony in which the cells are embedded in extracellular polysaccharides (epss), which play a crucial role in the extreme desiccation tolerance of this organism. when natural colonies were immersed in water, degradation of the colonies occurred within 2 days and n. commune cells were released into the water. the activities that hydrolyze glycoside bonds in various n. commune fractions were examined usi ...	2008	19029765
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
quantitative overview of n2 fixation in nostoc punctiforme atcc 29133 through cellular enrichments and itraq shotgun proteomics.	nostoc punctiforme atcc 29133 is a photoautotrophic cyanobacterium with the capacity to fix atmospheric n 2. its ability to mediate this process is similar to that described for nostoc sp. pcc 7120, where vegetative cells differentiate into heterocysts. quantitative proteomic investigations at both the filament level and the heterocyst level are presented using isobaric tagging technology (itraq), with 721 proteins at the 95% confidence interval quantified across both studies. observations from ...	2009	19012430
bioinformatic and expression analyses of genes mediating zinc homeostasis in nostoc punctiforme.	zinc homeostasis was investigated in nostoc punctiforme. cell tolerance to zn(2+) over 14 days showed that zncl(2) levels above 22 microm significantly reduced cell viability. after 3 days in 22 microm zncl(2), ca. 12% of the zn(2+) was in an edta-resistant component, suggesting an intracellular localization. zinquin fluorescence was detected within cells exposed to concentrations up to 37 microm relative to 0 microm treatment. radiolabeled (65)zn showed zn(2+) uptake increased over a 3-day peri ...	2009	19011078
characterization of a novel debranching enzyme from nostoc punctiforme possessing a high specificity for long branched chains.	a novel debranching enzyme from nostoc punctiforme pcc73102 (npde) exhibits hydrolysis activity toward both alpha-(1,6)- and alpha-(1,4)-glucosidic linkages. the action patterns of npde revealed that branched chains are released first, and the resulting maltooligosaccharides are then hydrolyzed. analysis of the reaction with maltooligosaccharide substrates labeled with (14)c-glucose at the reducing end shows that npde specifically liberates glucose from the reducing end. kinetic analyses showed ...	2009	19010304
characterization of cyanobacterial carotenoid ketolase crtw and hydroxylase crtr by complementation analysis in escherichia coli.	the pathway from beta-carotene to astaxanthin is a crucial step in the synthesis of astaxanthin, a red antioxidative ketocarotenoid that confers beneficial effects on human health. two enzymes, a beta-carotene ketolase (carotenoid 4,4'-oxygenase) and a beta-carotene hydroxylase (carotenoid 3,3'-hydroxylase), are involved in this pathway. cyanobacteria are known to utilize the carotenoid ketolase crtw and/or crto, and the carotenoid hydroxylase crtr. here, we compared the catalytic functions of c ...	2008	18987067
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
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
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
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
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
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