title: [Impact of nitrogen assimilation on regulation of antibiotic production in Streptomyces hygroscopicus 155].
abstract: The enzymes of the assimilation pathways in cultures of S. hygroscopicus grown in the presence of various nitrogen sources were investigated. No assimilation activity of glutamate dehydrogenase (GDH) was observed. Activities of alanine dehydrogenase (ADH), GDH, glutamine: 2-oxoglutarate aminotransferase (GOGAT) and glutamate synthetase (GS) were studied. High concentrations of ammonium and alanine induced ADH formation. The levels of GS remained low in media with NH4Cl. Various nitrogen sources had no impact on the activity of GOGAT which suggested the involvement of constitutive synthesis. ADH was likely to play an alternative role. Determination of the quantitative and qualitative composition of the free amino acids confirmed the involvement of the GS-GOGAT pathway in nitrogen assimilation. The concentration of ammonium ions in the media with one amino acid or in the presence of several amino acids lowered the antibiotic activity while in the media with alanine and the other nitrogen compounds it increased the antibiotic activity.
authors.forename: V
authors.initials: V
authors.lastname: Chipeva
authors.forename: E
authors.initials: E
authors.lastname: Dumanova
authors.forename: Ts
authors.initials: Ts
authors.lastname: Todorov
authors.forename: I
authors.initials: I
authors.lastname: Ivanova
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D009584:Nitrogen
vernacular_title: Vliianie azotnoĭ assimiliatsii na reguliatsiiu antibiotikoobrazovaniia u Streptomyces hygroscopicus 155.