Udo Gräfe

Microbiaeratin, a new natural indole alkaloid from a Microbispora aerata strain, isolated from Livingston Island, Antarctica.

Abstract A new sulphur‐containing natural alkaloid named microbiaeratin (1a) was isolated, together with the known microbiaeratinin (2, bacillamide) from the culture filtrate of Microbispora aerata strain IMBAS‐11A. The organism was isolated from penguin excrements collected on the Antarctic Livingston Island. The structure was elucidated by one‐ and two‐dimensional NMR experiments and mass spectrometric investigations.

Pleiotropic Effects of a Butyrolactone-type Autoregulator on Mutants of Streptomyces griseus Blocked in Cytodifferentiation

Mutants of Streptomyces griseus blocked in cytodifferentiation regained their capacity to form differentiated mycelia and/or anthracycline pigments in the presence of butyrolactone-type autoregulatory effectors such as trans-2-(6-methylheptanol-1-yl)-3-hydroxymethyl-4-butanolide+ ++. In the pertinent indicator strains, the effect has been correlated with the increase of lipid synthesis, with changes in the composition of lipid fraction and with the restoration of the production of neutral proteinases. The results suggest that autoregulatory butyrolactones from streptomycetes stimulate cytodifferentiation of their producers at an early stage of development.

Altered lipid composition in a non-differentiating derivative of Streptomyces hygroscopicus.

SUMMARY: The turimycin-producing Streptomyces hygroscopicus strain JA6599/NG60-93 (Tur+Amy+) and strain CC1, which is unable to produce antibiotic and aerial mycelium (Tur-Amy-), were compared with respect to their mycelial enzyme activities and cellular lipid composition. Changed activities of six enzymes of intermediary metabolism during submerged growth of strain CC1 on chemically defined medium attest to alterations of the life cycle. In addition, strain CC1 contained decreased amounts of 12-methyltetradecanoic acid in relation to 14-methylpentadecanoic acid (isopalmitic acid) and displayed a quantitatively altered phospholipid composition.