BACKGROUND Secondary metabolite production from wild strains is very low for economical purpose therefore certain strain improvement strategies are required to achieve hundred times greater yield of metabolites. Most important strain improvement techniques include physical and chemical mutagenesis. Broad spectrum mutagenesis through UV irradiation is the most important and convenient physical m...

results however the maximum production of avermectin b1b (17 mg/l) was obtained by using sm2 growth medium containing soluble corn starch, yeast extract, kcl, caco3 and mgso4 which was detected qualitatively by using tlc and quantitatively by hplc. conclusions maximum production was observed with initial medium ph of 7, 10% inoculum size with incubation temperature of 31°c for 10 days of fermen...

conclusions: the hereditary stability analysis of the uv mentioning 45 minutes revealed the uv exposure time for mutants and 3 represented the colony taken from the plate irradiated for 45 minutes mutant showed that the production of avermectin b1b remained constant and no reverse mutation occurred after 15 generations. results: avermectin b1b-hyper-producing mutant, produced using these three ...

The level of activity of avermectin B O-methyltransferase, the enzyme which catalyzes the conversion of avermectin B components to avermectin A components, was analyzed in a series of "Streptomyces avermitilis" mutants selected for increased production of the avermectins. In all of the mutants, increased avermectin production was accompanied by increased avermectin B O-methyltransferase activit...

Streptomyces ahygroscopicus ZB01 can effectively oxidize 4″-OH of avermectin to form 4″-oxo-avermectin. CYP107Z13 is responsible for this site-specific oxidation in ZB01. In the present study, we explored the electron transfer pathway in oxidation of avermectin by CYP107Z13 in ZB01. A putative [3Fe-4S] ferredoxin gene fd68 and two possible NADH-dependent ferredoxin reductase genes fdr18 and fdr...

The interactions of the anthelmintic agent avermectin B1a, the anticonvulsant pentobarbital, and the anxiolytic tracazolate with the gamma-aminobutyric acid (GABA) receptor . chloride ion channel complex in rat brain membrane were studied. The results indicated that they all potentiated ligand binding to the GABA and benzodiazepine receptors. The stimulatory effects of avermectin B1a and pentob...

In the theory of star formation, the first hydrostatic core (FHSC) phase is a critical step in which a condensed object emerges from a prestellar core. This step lasts about one thousand years, a very short time compared with the lifetime of prestellar cores, and therefore is hard to detect unambiguously. We present IRAM Plateau de Bure observations of the Barnard 1b dense molecular core, combi...

The root-knot nematode (RKN) is one of the most damaging agricultural pests.Effective biological control is need for controlling this destructive pathogen in organic farming system. During October 2010 to 2011, the nematicidal effects of the Syncephalastrum racemosum fungus and the nematicide, avermectin, alone or combined were tested against the RKN (Meloidogyne incognita) on cucumber under po...