Regulation of hydrolase formation and phosphate release in turimycin fermentations

Subcellular localization of enzymes in Streptomyces aureofaciens and its alteration by benzyl thiocyanate. I. Phosphatases and ATP-glucokinase

Mycelia of a low- and a high-production strain of Streptomyces aureofaciens were converted into protoplasts and divided into five subcellular fractions in order to localize exopolyphosphatases (EC 3.6.1.11), triphosphatase (EC 3.6.1.25), inorganic diphosphatase (EC 3.6.1.1), apyrase (EC 3.6.1.5) and glucokinase (EC 2.7.1.2). The highest specific activity of enzymes hydrolyzing polyphosphates was found in cytoplasmic vesicles and membranes. Triphosphatase was detected in the periplasmic fraction. Periplasmic vesicles and cytoplasm exhibited a high activity of diphosphatase. Apyrase was found mainly in the fractions of membranes and cytoplasmic vesicles. Glucokinase was a cytoplasmic enzyme. The enzymes were released from membrane structures into cytoplasm or periplasmic space if benzyl thiocyanate (10 microM) was present in the growth medium.

Localization of alkaline phosphatase in Streptomyces noursei

Alkaline phosphatase activity appeared in Streptomyces noursei strain IMET 43,716 when cultures were shifted to phosphate limitation. By using p-nitrophenylphosphate as substrate, the activity detected at pH 9.4 was cell-bound, as long as young mycelia were studied. Supernatant fluids of the cultures were only active, if partial mycelial lysis had taken place after incubation for several days under the influence of shear forces. After cytochemical staining the phosphatase reaction products were microscopically visible as grains distributed rather homogeneously within the hyphal lumen. The frequency of grains was correlated to the rate of nourseothricin production. Electron microscopy of thin sections showed the phosphatase reaction products to be only present in the cytoplasm.

[Effect of acetate on the formation of the phyoeffector tentoxin by Alternaria alternata (Fr.) Keissler]

The effect of the cosubstrate acetate on the formation of the phytotoxic substance tentoxin by Alternaria alternata (Fr.) Keissler was investigated. Acetate was taken up and metabolized during growth. The added acetate stimulated considerably the biosynthesis of tentoxin depending on its concentration and time of introduction. There was an increased incorporation of (U-14C)-glucose into the toxin molecule in the presence of acetate in the medium. The results indicate an induction of the biosynthesis of tentoxin by the precursor acetate, probably mediated through the accumulation of the glycolytic intermediates pyruvate and phosphoenolpyruvate.

Sequential processes of phosphate limitation and of phosphate release in streptomycin fermentations

The significance of the sequential processes of phosphate limitation and of phosphate release from medium constituents is demonstrated in technical streptomycin fermentations. The phosphate limitation initiated the streptomycin synthesis as well as the formation of phosphatases and protease. In later periods of the process the phosphate release influences especially the enzyme formation.