| role of cyanobacteria in the persistence of vibrio cholerae o139 in saline microcosms. | recently, a new strain of cholera, vibrio cholerae o139, has emerged as an epidemic strain, but there is little information about its environmental reservoir. the present investigation was aimed to determine the role of cyanobacteria in the persistence of v. cholerae o139 in microcosms. an environmental isolate of v. cholerae o139 and three cyanobacteria (anabaena sp., nostoc sp., and hapalosiphon sp.) were used in this study. survival of culturable v. cholerae o139 in microcosms was monitored u ... | 2004 | 15052315 |
| establishing a food-chain link between aquatic plant material and avian vacuolar myelinopathy in mallards (anas platyrhynchos). | avian vacuolar myelinopathy (avm) is a neurologic disease primarily affecting bald eagles (haliaeetus leucocephalus) and american coots (fulica americana). the disease was first characterized in bald eagles in arkansas in 1994 and then in american coots in 1996. to date, avm has been confirmed in six additional avian species. attempts to identify the etiology of avm have been unsuccessful to date. the objective of this study was to evaluate dermal and oral routes of exposure of birds to hydrilla ... | 2004 | 15465716 |
| 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 |
| 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 |
| recurrent adenylation domain replacement in the microcystin synthetase gene cluster. | microcystins are small cyclic heptapeptide toxins produced by a range of distantly related cyanobacteria. microcystins are synthesized on large nrps-pks enzyme complexes. many structural variants of microcystins are produced simultaneously. a recombination event between the first module of mcyb (mcyb1) and mcyc in the microcystin synthetase gene cluster is linked to the simultaneous production of microcystin variants in strains of the genus microcystis. | 2007 | 17908306 |
| physiological characterization and electron microscopic investigation of cyanobacteria associated with wheat rhizosphere. | physiological attributes of a set of cyanobacterial strains, isolated from the rhizosphere of wheat (var. hd 2687), identified as belonging to the genera calothrix (n = 3), westiellopsis (1), hapalosiphon (2) and nostoc (2), were axenized and evaluated. the concentrated culture filtrates of three cyanobacterial strains - c. ghosei, h. intricatus and nostoc sp. were able to enhance germination percentage, radicle and coleoptile length in inhibition experiments with wheat seeds. indole-3-acetic ac ... | 2009 | 19330544 |
| molecular characterization and the effect of salinity on cyanobacterial diversity in the rice fields of eastern uttar pradesh, india. | salinity is known to affect almost half of the world's irrigated lands, especially rice fields. furthermore, cyanobacteria, one of the critical inhabitants of rice fields have been characterized at molecular level from many different geographical locations. this study, for the first time, has examined the molecular diversity of cyanobacteria inhabiting indian rice fields which experience various levels of salinity. | 2009 | 19344531 |
| interactive effect of metal ions over exponential growth period of microalgal cells. | the interactive effect of metal ions namely chromium and iron has been studied under controlled conditions on the diazotropic cyanobacterium hapalosiphon stuhlmannii and the photosynthetic green alga scenedesmus quadricauda over the exponential growth period of the cells. the work describes by employing an exponential cell growth model, the effect of metal ions both individually and in combination, on the physiological and biochemical characteristics e.g. dry weight, chlorophylls, carotenoid and ... | 2006 | 17436535 |
| isolation of a nitrile-containing indole alkaloid from the terrestrial blue-green alga hapalosiphon delicatulus | ambiguine g nitrile is a new indole alkaloid from the terrestrial blue-green alga hapalosiphon delicatulus (uh isolate ic-13-1). it is the first nitrile to be found in the stigonemataceae. | 1998 | 9784177 |
| microtubule effects of welwistatin, a cyanobacterial indolinone that circumvents multiple drug resistance. | welwitindolinones are a family of novel alkaloids recently isolated from the blue-green alga hapalosiphon welwitschii. we demonstrate that incubation of sk-ov-3 human ovarian carcinoma cells and a-10 vascular smooth muscle cells with welwitindolinone c isothiocyanate, now termed welwistatin, results in dose-dependent inhibition of cell proliferation, which is correlated with increases in the percentage of cells in mitosis. treatment of a-10 cells with welwistatin resulted in reversible depletion ... | 1996 | 8632761 |
| welwitindolinone analogues that reverse p-glycoprotein-mediated multiple drug resistance. | welwitindolinones are a family of novel alkaloids recently isolated from the blue-green alga hapalosiphon welwitschii as a part of our effort to identify new compounds that overcome multiple drug resistance. the abilities of three structurally similar members of this family to interact with p-glycoprotein have been compared. similarly to the effects of verapamil, n-methylwelwitindolinone c isothiocyanate (compound 1) attenuated the resistance of mcf-7/adr cells to natural product anticancer drug ... | 1995 | 7870031 |
| Macromolecular Response of Individual Algal Cells to Nutrient and Atrazine Mixtures within Biofilms. | Pollutant effects on biofilm physiology are difficult to assess due to differential susceptibility of species and difficulty separating individual species for analysis. Also, measuring whole assemblage responses such as metabolism can mask species-specific responses, as some species may decrease and others increase metabolic activity. Physiological responses can add information to compositional data, and may be a more sensitive indicator of effect. It is difficult, however, to separate individua ... | 2011 | 22202888 |
| Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance. | Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30-ádays. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirm ... | 2011 | 21732035 |