| tolytoxin and new scytophycins from three species of scytonema. | tolytoxin [1], the major cytotoxin associated with scytonema mirabile strain by-8-1, scytonema burmanicum strain do-4-1 and scytonema ocellatum strains dd-8-1, ff-65-1, and ff-66-3, has been shown to be 6-hydroxy-7-o-methylscytophycin b. minor amounts of three other new cytotoxic scytophycins, 6-hydroxyscytophycin b [2], 19-o-demethylscytophycin c [3], and 6-hydroxy-7-o-methylscytophycin e [4], have also been isolated from these cyanophytes. the gross structures and stereochemistry are based on ... | 1990 | 2128517 |
| acute toxicity of the natural algicide, cyanobacterin, to daphnia magna. | cyanobacterin is a potent, photosynthetic inhibitor produced as a secondary metabolite by the filamentous, freshwater cyanobacterium scytonema hofmanni. with a spectrum of activity encompassing species of cyanobacteria and eucaryotic algae as well as higher plants, cyanobacterin might be utilized as a commercial algicide for algae waterbloom control. as a component of the preliminary environmental risk/hazard evaluation of this proposed application, the acute toxicity of cyanobacterin to the pla ... | 1990 | 2276362 |
| utilization of organic substrates by two filamentous cyanobacteria under various growth conditions. | two filamentous cyanobacteria calothrix marchica lemm. var. intermedia rao and scytonema schmidlei de toni grew heterotrophically in light with or without dcmu and in the dark when supplemented with glucose, fructose or sucrose. galactose, mannitol and sorbitol were utilized less efficiently. mannose, xylose and organic acids did not support the heterotrophic growth of both the cyanobacteria. by continuous incubation and sub-cultivation in sucrose supplemented medium in the dark, heterotrophic a ... | 1988 | 3142200 |
| fixation of elementary nitrogen by nostoc punctiforme (kütz.) hariot and scytonema bohneri schmidle in pure and unialgal cultures. | | 1970 | 5412270 |
| germination of hormocysts of scytonema javanicum and the function of blue-green algal heterocysts. | | 1968 | 5698762 |
| isolation of chlorine-containing antibiotic from the freshwater cyanobacterium scytonema hofmanni. | scytonema hofmanni, a filamentous freshwater cyanobacterium (blue-green alga), produces secondary metabolites which inhibit the growth of other cyanobacteria and green algae. a rapid, qualitative assay for this inhibition has been developed with synechococcus as the test organism. this assay procedure has led to the isolation and characterization of an antibiotic (named cyanobacterin) from scytonema. the antibiotic has a molecular weight of 430 and an empirical formula of c23h23o6cl and contains ... | 1982 | 6800032 |
| self-splicing group i intron in cyanobacterial initiator methionine trna: evidence for lateral transfer of introns in bacteria. | a group i self-splicing intron has been found in the anticodon loop of trna(fmet) genes in three cyanobacterial genera: dermocarpa, scytonema and synechocystis; it is absent in nine others. the synechocystis intron is also interrupted by an open reading frame (orf) of 150 codons. of these three bacteria, only scytonema also contains the group i intron that has previously been reported in trna(leu) (uaa) genes in both cyanobacteria and chloroplasts. the presence of an orf in the trna(fmet) intron ... | 1994 | 7523114 |
| regulation of scytophycin accumulation in cultures of scytonema ocellatum. ii. nutrient requirements. | the effects of optimal sources and concentrations of major nutrients (supplying n, s, p, k+, na+, ca2+, mg2+, and inorganic carbon) and organic buffers on growth and secondary metabolite accumulation in scytonema ocellatum strain ff-66-3 were determined. nitrate, phosphate, magnesium, and sulfur had no specific stimulatory or inhibitory effects on scytophycin accumulation within the range of concentrations that supported optimal growth. calcium concentrations greater than those required for grow ... | 1995 | 7546607 |
| scytophycin production by axenic cultures of the cyanobacterium scytonema ocellatum. | nonaxenic clones prepared from the cyanobacterium syctonema ocellatum lyngbye ex bornet et flahault strain ff-66-3 exhibited a high degree of heterogeneity with respect to tolytoxin titer. thirty-four of 114 clones (29.8%) isolated by fragmentation of scytonema filaments did not produce detectable amounts of tolytoxin in culture. one clone (designated so127) produced approximately twice as much tolytoxin as the parental culture and continued to produce tolytoxin after repeated subculture. three ... | 1994 | 7866663 |
| action of tolytoxin on cell morphology, cytoskeletal organization, and actin polymerization. | tolytoxin, a cytostatic, antifungal macrolide produced by blue-green algae of the genus scytonema, is a potent, reversible inhibitor of cytokinesis in cultured mammalian cells. treatment of kb cells with 2-16 nm tolytoxin results in profound morphological changes, beginning with the formation of zeiotic processes and culminating in nuclear protrusion. in l1210 cells, cytokinesis is inhibited by as little as 2 nm tolytoxin, while karyokinesis proceeds normally, resulting in polynucleation. tolyto ... | 1993 | 8319266 |
| new acylated sulfoglycolipids and digalactolipids and related known glycolipids from cyanobacteria with a potential to inhibit the reverse transcriptase of hiv-1. | five novel diacylated sulfoglycolipids (1-5) were isolated from the cyanobacterium scytonema sp. (tau strain sl-30-1-4) and four novel acylated diglycolipids (6-9) were isolated from the cyanobacterium oscillatoria raoi (tau strain il-76-1-2). these two groups of glycolipids and related known glycolipids isolated from these two and three other strains of cyanobacteria, phormidium tenue (tau strain il-144-1), o. trichoides (tau strain il-104-3-2), and o. limnetica (tau strain ng-4-1-2), were foun ... | 1997 | 9428159 |
| uvb-induced reduction in biomass and overall productivity of cyanobacteria. | effect of middle wave ultraviolet radiation (uvb) was studied in three different species of cyanobacteria (nostoc, anabaena and scytonema) by estimating their growth pattern, biomass yield, chlorophyll content, total starch and protein content. the results show that exposure of the cyanobacteria with uvb dose corresponding to an increase or decrease of 20% in its environmental flux will have drastic effects on biomass production, photosynthetic rate and nitrogen fixation. cyanobacteria are prima ... | 1998 | 9514891 |
| broad spectrum and mode of action of an antibiotic produced by scytonema sp. tistr 8208 in a seaweed-type bioreactor. | a photobioreactor was constructed using anchored polyurethane foam strips (1 x 1 x 40 cm) fixed onto a stainless-steel ring to prevent flotation, as a biomass support material (bsm). this type of reactor was named a seaweed-type bioreactor. a filamentous cyanobacterium, scytonema sp. tistr 8208, which produces a novel cyclic dodecapeptide antibiotic, was immobilized in seaweed-type photobioreactor and cultivated with air containing 5% co2 sparged at a gas flow rate of 250 ml/min under illuminati ... | 1998 | 9627386 |
| water binding in sub-aerial cyanobacteria. | the role of water in the maintenance of structural and functional integrity of the cell at different hydration levels has been a subject of wide understanding. water sorption isotherms, dielectrics and ir spectroscopic techniques were used to estimate the strength of water binding and number of binding sites using d'arcy/watt equation on the two well reported desiccation-tolerant cyanobacteria-scytonema geitleri and lyngbya arboricola. the observations made with water sorption isotherms, dielect ... | 1998 | 9699420 |
| effect of hydration and dehydration on initiation and dynamics of some physiological reactions in desiccation tolerant cyanobacterium scytonema geitleri. | the effect of hydration and dehydration has been studied on extent and recovery of some metabolic reactions in desiccation tolerant terrestrial cyanobacterium scytonema geitleri. the results show that the energy transducing reactions like photochemical reactions of photosynthesis recover first, followed by increase in atp pool size. during later phase of hydration, appearance of energy consuming processes such as co2 fixation and nitrogen fixation have been observed. sensitivity of reactions dur ... | 1998 | 9803667 |
| structural interactions among epilithic cyanobacteria and heterotrophic microorganisms in roman hypogea. | abstract phototrophic microbial communities present in the roman catacombs were characterized and different species of terrestrial epilithic cyanobacteria were found to occur as dominant organisms. eucapsis, leptolyngbya, scytonema, and fischerella were the most frequently encountered cyanobacterial taxa, while a few species of green algae and the diatom diadesmis gallica occurred in minor amounts. streptomyces strains, a few genera of eubacteria, and to a lesser extent fungi were always present ... | 1999 | 10541786 |
| involvement of the compatible solutes trehalose and sucrose in the response to salt stress of a cyanobacterial scytonema species isolated from desert soils. | the response to moderate salt stress of a scytonema species isolated from a soil crust in the arid region of central australia was studied. an increase in intracellular trehalose and sucrose concentrations was detected by nmr and hplc analysis following salt stress, maximal amounts being produced by exposure to 150 mm nacl after 48 h. when the organism was subsequently returned to normal growth conditions, the cellular concentrations of these solutes decreased. the biosynthesis of trehalose and ... | 1999 | 10564766 |
| heavy metal coprecipitation with hydrozincite [zn(5)(co(3))(2)(oh)(6)] from mine waters caused by photosynthetic microorganisms. | an iron-poor stream of nearly neutral ph polluted by mine tailings has been investigated for a natural phenomenon responsible for the polishing of heavy metals in mine wastewaters. a white mineralized mat, which was determined to be hydrozincite [zn(5)(co(3))(2)(oh)(6)] by x-ray diffraction analysis, was observed in the stream sediments mainly in spring. the precipitate shows a total organic matter residue of 10% dry weight and contains high concentrations of pb, cd, ni, cu, and other metals. sc ... | 2000 | 11055969 |
| is the 16s-23s rrna internal transcribed spacer region a good tool for use in molecular systematics and population genetics? a case study in cyanobacteria. | we amplified, ta-cloned, and sequenced the 16s-23s internal transcribed spacer (its) regions from single isolates of several cyanobacterial species, calothrix parietina, scytonema hyalinum, coelodesmium wrangelii, tolypothrix distorta, and a putative new genus (isolates srs6 and srs70), to investigate the potential of this dna sequence for phylogenetic and population genetic studies. all isolates carried its regions containing the sequences coding for two trna molecules (trna and trna). we retri ... | 2001 | 11371594 |
| induction of mycosporine-like amino acids (maas) in cyanobacteria by solar ultraviolet-b radiation. | three filamentous and heterocystous n(2)-fixing cyanobacteria, anabaena sp., nostoc commune and scytonema sp. were tested for the presence of ultraviolet-absorbing mycosporine-like amino acids (maas) and their induction by solar ultraviolet-b (uv-b) radiation. high performance liquid chromatographic (hplc) studies revealed the presence of only one type of maas in all three cyanobacteria, that was identified as shinorine, a bisubstituted maa containing both glycine and serine groups having an abs ... | 2001 | 11470569 |
| scyptolin a and b, cyclic depsipeptides from axenic cultures of scytonema hofmanni pcc 7110. | two novel cyclic depsipeptides were isolated from axenic cultures of the terrestrial cyanobacterium scytonema hofmanni pcc 7110 and designated scyptolin a and b. amino acid analyses in context with mass and 1h/13c nmr spectroscopies revealed a composition typical for heterologous cyanopeptolins but containing the uncommon residue 3'-chloro-n-methyl-tyr (cmtyr) and a unique sidechain. scyptolin a and b both consist of the n-acylated peptide but(1)-ala(2)-thr(3)-thr(4)-leu(5)-ahp(6) (3-amino-6-hyd ... | 2001 | 11730873 |
| physical, chemical, and microbiological characteristics of microbial mats (kopara) in the south pacific atolls of french polynesia. | microbial mats that develop in shallow brackish and hyposaline ponds in the rims of two french polynesian atolls (rangiroa and tetiaroa) were intensively investigated during the past three years. comparative assessment of these mats (called kopara in polynesian language) showed remarkable similarities in their composition and structure. due to the lack of iron, the color of the cyanobacterial pigments produced remained visible through the entire depth of the mats (20-40 cm depth), with alternate ... | 2001 | 11766060 |
| temporal variation in community composition, pigmentation, and f(v)/f(m) of desert cyanobacterial soil crusts. | summers on the colorado plateau (usa) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high uv and visible radiation. we investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. representative surface cores were sampled at the ene, wsw, and top microaspects of 20 individual soil crust pedicels at a single site in canyonlands national park, utah, in spring an ... | 2002 | 11984625 |
| isolation and structural elucidation of biologically active phospholipids from scytonema julianum (cyanobacteria). | the role of platelet-activating factor (paf) as a mediator appeared in rather primitive organisms like protozoans and was maintained in more evolved organisms. no reports exist for the presence of paf or paf analogues - or even compounds that exhibit paf-like activity - in cyanobacteria, even though they belong to a a group of organisms at a low evolutionary level where the content of alkylacyl forms of ether lipids is expected to be high. in addition, cyanobacteria serve as a rich source of nov ... | 2002 | 12038967 |
| cyanobacteria a potential source of antiviral substances against influenza virus. | aqueous and methanolic extracts of cultured cyanobacteria of several genera, microcystis, nodularia, oscillatoria, scytonema, lyngbya and calothrix were evaluated for their in vitro antiviral activity against influenza a virus in madin darby canine kidney cells. none of the methanolic extracts showed cytotoxic effects. the inhibitory concentration (ic(50)) of antiviral activity ranged between 20.0 micro g to 79.0 micro g extract/ml. the most active extract in this screening derived from genus mi ... | 2002 | 12458356 |
| variability of hydrocarbon and fatty acid components in cultures of the filamentous cyanobacterium scytonema sp. isolated from microbial community "black cover" of limestone walls in jerusalem. | the hydrocarbon and lipid components of four strains of the filamentous cyanobacterium scytonema sp. isolated from microbial community "black cover" of limestone walls in jerusalem were identified by gas chromatography-mass spectrometry using serially coupled capillary columns. the dominant compounds were: 1-heptadecyne (1.5-8%), hexadecanoic acid (14-36%), (z,z)-9,12-octadecadienoic acid (12-30%), (z,z,z)-9,12,15-octadecatrienoic acid (6-12%), n-heptadecane (4-16%), and 1-heptadecene (1.5-8%). ... | 2002 | 12495426 |
| a potent novel anti-hiv protein from the cultured cyanobacterium scytonema varium. | a new anti-hiv protein, scytovirin, was isolated from aqueous extracts of the cultured cyanobacterium scytonema varium. the protein displayed potent anticytopathic activity against laboratory strains and primary isolates of hiv-1 with ec50 values ranging from 0.3 to 22 nm. scytovirin binds to viral coat proteins gp120, gp160, and gp41 but not to cellular receptor cd4 or other tested proteins. this unique protein consists of a single 95-amino acid chain with significant internal sequence duplicat ... | 2003 | 12614152 |
| effects of uv and visible light on cyanobacteria at the cellular level. | the effect of uv and visible light on cyanobacteria was determined at the cellular level by means of epifluorescence and confocal microscopy techniques. these methods allow the examination of light effects in spatial resolution. series of measurements were performed to determine the effect of different light qualities and quantities on cyanobacteria. to analyze the effect of the light quality, samples of anabaena and scytonema sp. were exposed to intense blue, green or red light applied from the ... | 2002 | 12659496 |
| [associative cyanobacteria isolated from the roots of epiphytic orchids]. | associative cyanobacteria were isolated from the rhizoplane and velamen of the aerial roots of the epiphytic orchids acampe papillosa, phalaenopsis amabilis, and dendrobium moschatum and from the substrate roots of acampe papillosa and dendrobium moschatum. cyanobacteria were isolated on complete and nitrogen-free variants of bg-11 medium. on all media and in all samples, cyanobacteria of the genus nostoc predominated. nostoc, anabaena, and calothrix were isolated from the surface of the a. papi ... | 2003 | 12698800 |
| molecular characterization of endolithic cyanobacteria inhabiting exposed dolomite in central switzerland. | the phototrophic microbial community inhabiting exposed dolomite in the alpine piora valley (switzerland) forms a distinct endolithic bilayer that features adjacent red dolomite (exterior) and green dolomite (interior) layers that are c. 0.5-1 mm below the rock surface. characterization of the community, with an emphasis on cyanobacteria, was conducted with culture-dependent and -independent approaches. direct microscopy of green dolomite revealed four distinct morphotypes consistent with chloro ... | 2003 | 12823194 |
| sterol compositions of the filamentous nitrogen-fixing terrestrial cyanobacterium scytonema sp. | thirteen unsaturated sterols were identified by gas chromatography--mass spectrometry using serially-coupled capillary columns from the filamentous nitrogen-fixing terrestrial cyanobacterium scytonema sp. isolated from the microbial community of cyanobacterial on 'black cover' biofilms limestone walls in jerusalem. the dominant sterols were cholest-5-en-3 beta-ol (18.9%), 3 beta-methoxycholest-5-ene (16.2%) and 3 beta-acetoxycholest-5-ene (11.2%). | 2003 | 12879746 |
| viability of dried vegetative cells or filaments, survivability and/or reproduction under water and light stress, and following heat and uv exposure in some blue-green and green algae. | vegetative cells in dried, mucilagenous mass of gloeocapsa aeruginosa and aphanothece nidulans, reticulum of hydrodictyon reticulatum, mucilagenous mass of chroococcus minor, and filaments of oedogonium sp. and scytonema hofmanni died within 1/2, 1/2, 1/2, 1, 3 and 6 h, respectively, while dried vegetative filaments of phormidium foveolarum retained under similar storage conditions viability for 4 d. p. foveolarum tolerated 1 mol/l nacl. the resistance to desiccation in p. foveolarum exhibited s ... | 2003 | 14533482 |
| hofmannolin, a cyanopeptolin from scytonema hofmanni pcc 7110. | two depsipeptide metabolites, scyptolin a and b, were reported recently from the axenically grown terrestrial cyanobacterium scytonema hofmanni pcc 7110. a related, novel depsipeptide was isolated from this scytonema and designated hofmannolin. the amino acid analysis in context with infrared, mass and 1h/13c-nmr spectroscopies revealed a cyclic depsipeptide structure of m(r) 1073 belonging to the class of cyanopeptolins. two peculiar features distinguish hofmannolin from other cyanopeptolins: o ... | 2003 | 14568072 |
| binding structure of elastase inhibitor scyptolin a. | natural bioactive compounds are of general interest to pharmaceutical research because they may be used as leads in drug development campaigns. among them, scyptolin a and b from scytonema hofmanni pcc 7110 are known to inhibit porcine pancreatic elastase, which in turn resembles the attractive drug target neutrophil elastase. the crystal structure of scyptolin a as bound to pancreatic elastase was solved at 2.8 a resolution. the inhibitor occupies the most prominent subsites s1 through s4 of th ... | 2003 | 14583266 |
| response of desert biological soil crusts to alterations in precipitation frequency. | biological soil crusts, a community of cyanobacteria, lichens, and mosses that live on the soil surface, occur in deserts throughout the world. they are a critical component of desert ecosystems, as they are important contributors to soil fertility and stability. future climate scenarios predict alteration of the timing and amount of precipitation in desert environments. because biological soil crust organisms are only metabolically active when wet, and as soil surfaces dry quickly in deserts du ... | 2004 | 14689292 |
| diazotrophic community structure and function in two successional stages of biological soil crusts from the colorado plateau and chihuahuan desert. | the objective of this study was to characterize the community structure and activity of n2-fixing microorganisms in mature and poorly developed biological soil crusts from both the colorado plateau and chihuahuan desert. nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the colorado plateau site and chihuahuan desert site, respectively. analysis of nifh sequences by clone sequencing and the terminal restriction fragment length poly ... | 2004 | 14766579 |
| new pigments from the terrestrial cyanobacterium scytonema sp. collected on the mitaraka inselberg, french guyana. | inselbergs are hills rising abruptly from the surrounding plains where cyanobacteria are the only living organisms under conditions of intense solar radiation. a survival mechanism to prevent uv-damage has been associated with synthesis of the ultraviolet-screening, photostable sheath pigment scytonemin. the organic extract of scytonema sp., collected on the mitaraka inselberg, french guyana, yielded three new pigments, tetramethoxyscytonemin (1), dimethoxyscytonemin (2), and scytonine (3), deri ... | 2004 | 15104503 |
| characterization of bioactive glycolipids from scytonema julianum (cyanobacteria). | cyanobacteria serve as a rich source of novel bioactive metabolites. few studies on glycolipids reported them as having specific biological activities. in this study, total lipids of scytonema julianum, a filamentous cyanobacterium isolated from a greek cave, were separated into neutral and phospho- and glycolipids, and the latter were further fractionated by high-performance liquid chromatography (hplc). each glycolipid fraction was tested in vitro for its ability to inhibit platelet-activating ... | 2005 | 15649769 |
| a correlation matrix of alkaline phosphatase and sporulation in diazotrophic cyanobacteria and its thermo-tolerant mutant. | alkaline phosphatase (phosphomonoesterase i.e. pmease) activity in heterocystous cyanobacteria anabaena flos-aquae, nostoc calcicola, calothrix brevissima, scytonema javanicum and hapalosiphon intricatus is known to be temperature and ph dependent. maximum level of enzyme activity was recorded at either 35 degrees c or 37.5 degrees c. also, the cell bound phosphomonoesterase enzyme was shown to exhibit ph optima of 10.0 or 10.2. a thermo-tolerant (tr) mutant isolated after mnng (n-methyl-n'-nitr ... | 2004 | 15790075 |
| carbohydrate, glycolipid, and lipid components from the photobiont (scytonema sp.) of the lichen, dictyomema glabratum. | the photobiont of the lichen, dictyonema glabratum (scytonema sp.), was isolated and cultivated in a soil-extract medium and submitted to chemical analysis. successive extractions with chcl3-meoh, aqueous meoh, and h2o gave rise to solutions of lipids (25%), low-molecular-weight carbohydrates (22%), and polysaccharides (4%), respectively. tlc of the lipid extract showed the presence of glycolipids, which were further purified and examined by nmr spectroscopy and gc-ms. monogalactosyldiacylglycer ... | 2005 | 15963960 |
| overexpression and purification of scytovirin, a potent, novel anti-hiv protein from the cultured cyanobacterium scytonema varium. | scytovirin (svn) is a novel anti-human immunodeficiency virus (hiv) protein isolated from aqueous extracts of the cultured cyanobacterium scytonema varium. the protein consists of a single 95-amino acid chain with significant internal sequence duplication and 10 cysteines forming five intrachain disulfide bonds. a synthetic gene that encodes scytovirin was constructed, and expressed in escherichia coli, with thioredoxin (trx) fused to its n-terminus (trx-svn). most of the expressed protein was i ... | 2006 | 16289703 |
| methods involving light variation for isolation of cyanobacteria: characterization of isolates from central australia. | we report the isolation of organisms belonging to a range of cyanobacterial genera from the remote arid region of central australia, together with a preliminary characterization of their temporal modes of nitrogen fixation. we rendered unialgal dermocarpa and myxosarcina spp. (section ii organisms), lpp group b: type x (section iii), and scytonema and nostoc spp. (section iv). we developed an isolation procedure based on a combination of published methods and applicable to a broad spectrum of cy ... | 1992 | 16348803 |
| potent anti-hiv activity of scytovirin domain 1 peptide. | scytovirin (svn) is a novel anti-hiv protein isolated from aqueous extracts of the cultured cyanobacterium scytonema varium. svn contains two apparent domains, one comprising amino acids 1-48 and the second stretching from amino acids 49 to 95. these two domains display significant homology to each other and a similar pattern of disulfide bonds. two dna constructs encoding scytovirin 1-48 (cys7ser) (sd1) and 49-95 (cys55ser) (sd2) were constructed, and expressed in e. coli, with thioredoxin fuse ... | 2006 | 16647158 |
| activity of the natural algicide, cyanobacterin, on angiosperms. | cyanobacterin is a secondary metabolite produced by the cyanobacterium (blue-green alga) scytonema hofmanni. the compound had previously been isolated and chemically characterized. it was shown to inhibit the growth of algae at a concentration of approximately 5 micromolar. cyanobacterin also inhibited the growth of angiosperms, including the aquatic, lemna, and terrestrial species such as corn and peas. in isolated pea chloroplasts, cyanobacterin inhibited the hill reaction when p-benzoquinone, ... | 1986 | 16664727 |
| effects of cyanobacterial extracellular products and gibberellic acid on salinity tolerance in oryza sativa l. | salt stress is one of the most serious factors limiting the productivity of rice, the staple diet in many countries. gibberellic acid has been reported to reduce nacl-induced growth inhibition in some plants including rice. most paddy soils have a natural population of cyanobacteria, prokaryotic photosynthethic microorganisms, which synthesize and liberate plant growth regulators such as gibberellins that could exert a natural beneficial effect on salt stressed rice plants. the aim of this work ... | 2006 | 16756665 |
| survival of blue-green and green algae under stress conditions. | terrestrial blue-green algae scytonema millei, phormidium bohneri and lyngbya mesotricha survived to 100 % at atmospheric temperatures of 5-36 degrees c and relative humidity 55-100 % in rainy, winter and spring seasons but the survival was 15-25 % in summer when atmospheric temperature reached 48 degrees c and relative humidity was < or =23 %. microcoleus chthonoplastes maximum survival was =80 % in rainy season followed by a decrease to =1/2 and 1/4 level in winter and spring, respectively; it ... | 2006 | 16821721 |
| nutrient modulated alkaline phosphatase and associated processes in diazotrophic cyanobacteria. | nutrient regulation of alkaline phosphatase (phosphomonoesterase - pmease) was studied in some diazotrophic cyanobacterial strains like anabaena variabilis, anabaena torulosa, calothrix brevissima, scytonema javanicum and hapalosiphon intricatus, in response to the macronutrients (phosphate, calcium and magnesium) and the micronutrients (zinc, copper, iron and manganese). the phosphate grown cells of cyanobacterial strains when transferred to the phosphate deficient medium, showed expression of ... | 2006 | 16878605 |
| biogenic black crusts on buildings in unpolluted environments. | samples of peeling black crusts from modern and historic buildings in campeche, mexico, from a gravestone on the island of dom khon, lao, and from the anglican cathedral in belize city were analyzed microbiologically, by scanning electron microscopy plus electron dispersive spectroscopy (eds) and for pigment composition. in all cases, the surface was covered by a thick mat of cyanobacteria with dark brown sheaths. these were filamentous organisms of the genera scytonema or fischerella/mastigocla ... | 2007 | 17211538 |
| three distinct clades of cultured heterocystous cyanobacteria constitute the dominant n2-fixing members of biological soil crusts of the colorado plateau, usa. | the identity of the numerically dominant n(2)-fixing bacteria in biological soil crusts of the colorado plateau region and two outlying areas was determined using multiple approaches, to link the environmental diversity of nifh gene sequences to cultured bacterial isolates from the regions. of the nifh sequence-types detected in soil crusts of the colorado plateau, 89% (421/473) were most closely related to nifh signature sequences from cyanobacteria of the order nostocales. n(2)-fixing cyanobac ... | 2007 | 17381526 |
| the novel fold of scytovirin reveals a new twist for antiviral entry inhibitors. | the solution structure of the potent 95 residue anti-hiv protein scytovirin has been determined and two carbohydrate-binding sites have been identified. this unique protein, containing five structurally important disulfide bonds, demonstrates a novel fold with no elements of extended regular secondary structure. scytovirin contains two 39 residue sequence repeats, differing in only three amino acid residues, and each repeat has primary sequence similarity to chitin binding proteins. both sequenc ... | 2007 | 17434526 |
| genetic analysis of polyketide synthase and peptide synthetase genes in cyanobacteria as a mining tool for secondary metabolites. | molecular screening using degenerate pcr to determine the presence of secondary metabolite genes in cyanobacteria was performed. this revealed 18 nrps and 19 pks genes in the 21 new cyanobacterial strains examined, representing three families of cyanobacteria (nostocales, chroococales and oscillatoriales). a blast analysis shows that these genes have similarities to known cyanobacterial natural products. analysis of the nrps adenylation domain indicates the presence of novel features previously ... | 2007 | 17457628 |
| survival and reproduction in some algae under stress conditions. | pithophora oedogonia and cladophora glomerata survived lowest 60 and 58%, respectively, in june when the pond diurnal water temperature (pdwt) increased to a maximum of 28 degrees c. the lowering of pdwt only by 1 degrees c in july improved survivability of both algae to their almost maximum level of 100 and 96%, respectively. further lowering of pdwt to 17-22 degrees c in november initiated akinete formation in p. oedogonia. the process of akinete initiation, maturation and germination continue ... | 2007 | 18450223 |
| broad spectrum and mode of action of an antibiotic produced by scytonema sp. tistr 8208 in a seaweed-type bioreactor. | a photobioreactor was constructed using anchored polyurethane foam strips (1 x 1 x 40 cm) fixed onto a stainless-steel ring to prevent flotation, as a biomass support material (bsm). this type of reactor was named a seaweed-type bioreactor. a filamentous cyanobacterium, scytonema sp. tistr 8208, which produces a novel cyclic dodecapeptide antibiotic, was immobilized in seaweed-type photobioreactor and cultivated with air containing 5% co2 sparged at a gas flow rate of 250 ml/min under illuminati ... | 1998 | 18575994 |
| morphological variability in selected heterocystous cyanobacterial strains as a response to varied temperature, light intensity and medium composition. | the effect of temperature, light and nutrient composition on morphological traits was determined in seven nostocacean cyanobacteria (anabaena planctonica, a. sphaerica var. conoidea, a. spiroides, aphanizomenon gracile, nostoc sp., scytonema sp., and tolypothrix sp.). their morphological variability was high but only some of the features showed changes reflecting varied growth conditions. the frequency of heterocyst occurrence decreased with increasing nitrogen concentration. within the range st ... | 2008 | 18759118 |
| isolation and structure determination of a proteasome inhibitory metabolite from a culture of scytonema hofmanni. | cyanobacteria, blue-green algae, are a rich source of bioactive secondary metabolites with many potential applications. the ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. thus, proteasome inhibitors can be potential anticancer agents. cyanobacteria have been shown to be a rich source of highly ... | 2008 | 18955814 |
| extracellular phycoerythrin-like protein released by freshwater cyanobacteria oscillatoria and scytonema sp. | during growth of the freshwater cyanobacteria, oscillatoria sp. btcc/a0004, and scytonema sp. tistr 8208, a pink pigment is released into the growth medium. the pigment from each source had a molecular weight of approximately 250 kda and had adsorption maxima at 560 and 620 nm. these results suggest that pink pigment is a phycoerythrin-like protein. it inhibited the growth of green algae, chlorella fusca and chlamydomonas reinhardtii, but not other cyanobacteria or true bacteria. the concentrati ... | 2009 | 19271155 |
| survival and reproduction of some blue-green and green algae as affected by sewage water, fertilizer factory effluent, brassica oil, phenol, toluene and benzene. | fourteen blue-green and green algae survived for widely different time periods ranging between 22-102 d in control culture medium. irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different morphological types or natural habitats, they all survived for a short time period ranging between 3-8 d in sewage water, 5-10 d in fertilizer factory effluent, (1/4)-2 d in brassica oil, (1/2)-2 d in phenol, 1-3 d in toluene, and 1-4 d in benzene ... | 2009 | 19330547 |
| an antimicrobial guanidine-bearing sesterterpene from the cultured cyanobacterium scytonema sp. | scytoscalarol (1), a antimicrobial sesterterpene bearing a guanidino group, was isolated from the cultured cyanobacterium scytonema sp. (utex 1163) by bioassay-guided fractionation. the chemical structure was determined by spectroscopic analysis including ms and 1d and 2d nmr. scytoscalarol (1) showed antimicrobial activities against bacillus anthracis, staphylococcus aureus, escherichia coli, candida albicans, and mycobacterium tuberculosis with mic values in the range from 2 to 110 microm. | 2009 | 19888742 |
| 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 |
| scytonemides a and b, cyclic peptides with 20s proteasome inhibitory activity from the cultured cyanobacterium scytonema hofmanii. | two cyclic peptides, scytonemides a (1) and b (2), were isolated from the cultured fresh water cyanobacterium scytonema hofmannii (utex 1834) by bioassay-guided fractionation using a proteasome inhibition assay. the planar structures of the compounds were determined by a combination of ms and 1d and 2d nmr spectroscopy. the advanced marfey's method was used to determine the absolute configuration of both peptides. scytonemide a possesses an unusual imino linkage, while scytonemide b is a depsipe ... | 2010 | 21058727 |
| first report of saxitoxin production by a species of the freshwater benthic cyanobacterium, scytonema agardh. | saxitoxins or paralytic shellfish poisons (psp) are neurotoxins produced by some species of freshwater cyanobacteria and marine dinoflagellates. samples collected from the metaphyton of a drinking-water supply's pre-treatment reservoir and a small eutrophic lake in new zealand returned positive results when screened using a jellett psp rapid test kit. the dominant species in the sample was identified as scytonema cf. crispum. a non-axenic clonal culture (ucfs10) was isolated from the lake. the p ... | 2011 | 21223973 |
| molecular analysis of bacterial communities in uranium ores and surrounding soils from banduhurang open cast uranium mine, india: a comparative study. | bacterial community structure of heavy metal rich- uranium ores and surrounding soils was explored using 16s rrna gene based clone library analysis and denaturing gradient gel electrophoresis (dgge) to provide baseline microbial diversity data on autochthonous communities. sequence analysis of major ribotypes and/or dgge bands revealed proteobacteria and acidobacteria as the two most frequently present bacterial phyla across the samples, although relative abundance of each phyla and identity of ... | 2011 | 21308598 |
| 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 |
| chemotaxonomy of heterocystous cyanobacteria using fame profiling as species markers. | the fatty acid methyl ester (fame) analysis of the 12 heterocystous cyanobacterial strains showed different fatty acid profiling based on the presence/absence and the percentage of 13 different types of fatty acids. the major fatty acids viz. palmitic acid (16:0), hexadecadienoic acid (16:2), stearic acid (18:0), oleic acid (18:1), linoleic (18:2), and linolenic acid (18:3) were present among all the strains except cylindrospermum musicola where oleic acid (18:1) was absent. all the strains show ... | 2011 | 21761281 |
| Convergent evolution of a symbiotic duet: The case of the lichen genus Polychidium (Peltigerales, Ascomycota). | • Premise of the study: Thallus architecture has long been a powerful guide for classifying lichens and has often trumped photobiont association and ascomatal type, but the reliability of these characters to predict phylogenetic affinity has seldom been tested. The cyanolichen genus Polychidium unites species that have strikingly similar gross morphology but consort with different photobiont genera. If Polychidium were found to be monophyletic, photobiont switching among closely related species ... | 2011 | 21980162 |
| microbial biofilms on the sandstone monuments of the angkor wat complex, cambodia. | discoloring biofilms from cambodian temples angkor wat, preah khan, and the bayon and west prasat in angkor thom contained a microbial community dominated by coccoid cyanobacteria. molecular analysis identified chroococcidiopsis as major colonizer, but low similarity values (<95%) suggested a similar genus or species not present in the databases. in only two of the six sites sampled were filamentous cyanobacteria, microcoleus, leptolyngbya, and scytonema, found; the first two detected by sequenc ... | 2011 | 22006074 |