Cell protein profiles of submerged cultures of Streptomyces aureofaciens cultivated in the absence or presence of 12 microM benzyl thiocyanate (BT) were analyzed by one-dimensional SDS polyacrylamide gel electrophoresis. Substantial increase in the intensity of the 13, 35, 37, 60, and 100 kDa protein bands was observed in cultures treated with BT. Similar increase in the 35, 37, and 60 kDa bands was found in a mutant blocked in the last chlortetracycline biosynthesis step. Effect of BT on the solid medium-grown cultures was also observed, with a more intensive substrate mycelium pigmentation and alteration in the spore size and shape as the most characteristic features. Earlier studies of BT effect involving those on the stimulation of chlortetracycline biosynthesis are summarized and a possible signal-transducing mechanism is discussed from the point of view of adaptation of S. aureofaciens to the uncoupling of oxidative phosphorylation.

• MeSH
• Bacterial Proteins metabolism   MeSH
• Microscopy, Electron MeSH
• Streptomyces aureofaciens drug effects   metabolism   ultrastructure   MeSH
• Tetracyclines biosynthesis   MeSH
• Thiocyanates pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bacterial Proteins MeSH
• benzyl thiocyanate MeSH Browser
• Tetracyclines MeSH
• Thiocyanates MeSH

By using both the traditional International Streptomycetes Project methods and chemical approaches followed by a hierarchical cluster analysis, Streptomyces virginiae mutants A-1 and B-43 (yielding higher amounts of the M1 component of virginiamycin complex), their wild ancestor ATCC 13161, and another virginiamycin producer, S. pristinaespiralis NRRL 2958, were subjected to taxonomic studies to find kinship or differences among the strains. Of the methods used, only the test of carbon utilization, investigation of spore surface and analysis of sugar constituents of cell walls proved to be reliable enough to demonstrate the species identity of S. virginiae strains and to distinguish them from S. pristinaespiralis. L,L-2,6-Diaminopimelic acid was present in all strains. Analysis of fatty acids and total proteins as well as investigations of morphology and pigmentation of agar cultures led to confusing results.

• MeSH
• Electrophoresis, Polyacrylamide Gel MeSH
• Mutation * MeSH
• Streptomyces classification   genetics   growth & development   metabolism   MeSH
• Virginiamycin biosynthesis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Virginiamycin MeSH

An asporogenous spontaneous mutant of Streptomyces aureofaciens named ASR1 was selected on streptomycin gradient plates. The mutant is very stable and differs in ultrastructure and morphology, it is prototrophic but it lost the ability to grow well on soybean extract medium and produces one-tenth tetracyclines of the parent. The ASR1 mutant has a 3-4-fold increased resistance to streptomycin and is cross-resistant to other aminoglycosides. Comparison of the protein profiles from both strains on SDS gels revealed a very low expression of a 29.5 kDa protein in the ASR1 mutant which is overexpressed in both vegetative cells and spores of the parental strain.

• MeSH
• Aminoglycosides MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Drug Resistance, Microbial genetics   MeSH
• Bacterial Proteins genetics   isolation & purification   MeSH
• Mutation MeSH
• Spores, Bacterial genetics   MeSH
• Streptomyces aureofaciens drug effects   genetics   ultrastructure   MeSH
• Tetracycline biosynthesis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Aminoglycosides MeSH
• Anti-Bacterial Agents MeSH
• Bacterial Proteins MeSH
• Tetracycline MeSH

Valine dehydrogenase was purified to homogeneity from the crude extracts of Streptomyces aureofaciens. The molecular weight of the native enzyme was 116,000 by equilibrium ultracentrifugation and 118,000 by size exclusion high-performance liquid chromatography. The enzyme was composed of four subunits with molecular weights of 29,000. The isoelectric point was 5.1. The enzyme required NAD+ as a cofactor, which could not be replaced by NADP+. Sulfhydryl reagents inhibited the enzyme activity. The pH optimum was 10.7 for oxidative deamination of L-valine and 9.0 for reductive amination of alpha-ketoisovalerate. The Michaelis constants were 2.5 mM for L-valine and 0.10 mM for NAD+. For reductive amination the Km values were 1.25 mM for alpha-ketoisovalerate, 0.023 mM for NADH, and 18.2 mM for NH4Cl.

• MeSH
• Kinetics MeSH
• Macromolecular Substances MeSH
• Molecular Weight MeSH
• Amino Acid Oxidoreductases isolation & purification   metabolism   MeSH
• Enzyme Stability MeSH
• Streptomyces enzymology   growth & development   MeSH
• Substrate Specificity MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Macromolecular Substances MeSH
• Amino Acid Oxidoreductases MeSH
• valine dehydrogenase (NAD+) MeSH Browser