Electron-cytochemical demonstration of polyphosphates and the appropriate phosphatases in the glycocalyx ofStreptomyces aureofaciens

Antibiotics

The chapter informs about different types of antibiotics, their structure, biosynthesis and their regulation. Industrial cultivation and isolation of antibiotics is described in the chapter. Search for microorganisms producing antibiotics and preparation of high-producing strains is described. Resistance against antibiotics in producing microorganisms and pathogens is discussed.

Isolation and characterization of glycocalyx in Streptomyces aureofaciens

The surface layer, considered to be glycocalyx according to electron-microscopic observations, was separated from a low-production strain of Streptomyces aureofaciens by solubilization with urea and subsequent sonication. The isolation procedure was developed using various agents; neutral phosphatase served as a marker indicating the amount of the material released. The peripheral structure consisted predominantly of glycoprotein and differed from S-layers.

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.