No abstract

A47934, a peptide antibiotic produced by Streptomyces toyocaensis, belongs to the glycopeptide class of compounds which includes ristocetin and vancomycin. Incorporation studies with radioisotope-labeled substrates indicated that tyrosine, p-hydroxyphenylglycine, p-hydroxyphenylglyoxylate, acetate, and sulfate were efficiently incorporated into A47934. This is consistent with the reported biosynthesis of other glycopeptide antibiotics. Prototrophic mutants blocked in antibiotic biosynthesis were isolated at a low frequency (0.4%) after mutagenesis. Secretor-convertor pairings of the 36 mutants obtained demonstrated that they belonged to three classes: two groups of secretor-convertor pairs and a larger group of mutants that did not make antibiotic under any condition tested. Neither the secretor-convertor studies not supplementation of the cultures with putative biosynthetic intermediates was useful in identifying the location of the biosynthetic blocks. All studies to determine the timing of the sulfate addition step in the biosynthesis indicated that the sulfate is added prior to the formation of intermediates that possess antimicrobial activity.

No abstract

An unknown species of Alternaria , when grown on a medium containing carboxymethylcellulose as a carbon source produced a mixture of extracellular enzymes which solubilized acid-swollen cellulose. The product of the hydrolysis was a 1:2 molar mixture of cellobiose and glucose. The organism apparently produced no cellobiase. It is suggested that the mixture of cellulolytic enzymes contains at least two different enzymes which degrade cellulose in an endwise manner.

, AND DONALD J. SIEHR. Solubilization of acid-swollencellulose by anenzyme system from a species of Alternaria. Appl. Microbiol. 14:1015-1018. 1966.-An unknown species of Alternaria, when grown on a medium containing carboxymethylcellulose as a carbon source produced a mixture of extracellular enzymes which solubilized acid-swollen cellulose. The product of the hydrolysis was a 1:2 molar mixture of cellobiose and glucose. The organism apparently produced no cellobiase. It is suggested that the mixture of cellulolytic enzymes contains at least two different enzymes which degrade cellulose in an endwise manner.