Isolation and Characterization of Nitrogen-deregulated Mutants of Streptomyces clavuligerus

Isolation and characterization of furanomycin nonproducing Streptomyces threomyceticus mutants.

Stable mutants that are blocked in the production of the polyketide antibiotic furanomycin were generated by treatment of Streptomyces threomyceticus (ATCC 15795) with a combination of N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and ultraviolet light. On the basis of their cosynthetic properties in mixed culture, the mutants were grouped into eleven phenotypic classes. The polarity of the cosynt...

pcd mutants of Streptomyces clavuligerus still produce cephamycin C.

Biosynthesis of cephamycin C in Streptomyces clavuligerus involves the initial conversion of lysine to alpha-aminoadipic acid. Lysine-6-aminotransferase and piperideine-6-carboxylate dehydrogenase carry out this two-step reaction, and genes encoding each of these enzymes are found within the cephamycin C gene cluster. However, while mutation of the lat gene causes complete loss of cephamycin pr...

Isolation and characterization of a phage active against streptomyces griseus

Regulation of nitrogen catabolic enzymes in Streptomyces clavuligerus.

The levels of several enzymes involved in assimilation of different nitrogen compounds were investigated in Streptomyces clavuligerus in relation to the nitrogen source supplied to the cultures. Threonine dehydratase, serine dehydratase, proline dehydrogenase, histidase and urocanase were not decreased in the presence of ammonium. The latter two enzymes were induced by histidine in the culture ...

synthesis and characterization of some macrocyclic schiff bases

ماکروسیکلهای شیف باز از اهمیت زیادی در شیمی آلی و دارویی برخوردار می باشند. این ماکروسیکلها با دارابودن گروه های مناسب در مکانهای مناسب می توانند فلزاتی مثل مس، نیکل و ... را در حفره های خود به دام انداخته، کمپلکسهای پایدار تولید نمایند. در این پایان نامه ابتدا یک دی آلدئید آروماتیک از گلیسیرین تهیه می شود و در مرحله بعدی واکنش با دی آمینهای آروماتیک و یا آلیفاتیک در رقتهای بسیار زیاد منجر به ت...