In situ localization of manganese peroxidase production in mycelial pellets of Phanerochaete chrysosporium.

The ultrastructure of Phanerochaete chrysosporium hyphae from pellets in submerged liquid cultures was investigated in order to learn more about the interrelation between fungal architecture and manganese peroxidase (MnP) production. At day 2 of cultivation, some subapical regions of hyphae in the outer and middle zones of the pellet initiated differentiation into intercalary thick-walled chlamydospore-like cells of about 10 micro m diameter. At the periphery of the cytoplasm of these cells, a large number of mitochondria and Golgi-like vesicles were observed. The sites of MnP production were localized at different stages of cultivation by an immunolabelling procedure. The immunomarker of MnP was mainly concentrated in the chlamydospore-like cells and principally distributed in Golgi-like vesicles located at the periphery of the cytoplasm. The apices of hyphae in the outer layer of the pellets were apparently minor sites of MnP production. Maximal MnP release into the culture supernatant coincided with apparent autolysis of the chlamydospore-like cells. Production of extracellular autolytic chitinase and protease coincided with the disappearance of these structures from the pellets. The chlamydospore-like cells observed in the mycelial pellets of P. chrysosporium could be metabolically active entities operating as an enzyme reservoir, delivering their content into the surrounding medium possibly by an enzyme-mediated autolytic process.

Screening and search for novel inhibitors of DD-peptidase 64-575.

The aim of the work was search for inhibitors of PBPs (penicillin binding proteins, DD-carboxypeptidase/transpeptidase, DD-peptidase). Between 141 tested Streptomyces strains, 25% showed activity of inhibitors production. The inhibitors were produced by selected Streptomyces strains (NIH Culture Collection). The culture supernatants of Streptomyces rimosus B PZH (inhibitor B) and Streptomyces rimosus NRRL 2234 (inhibitor 2234) exhibited the highest inhibition activity. Both inhibitors were purified by the use of: anion exchange chromatography and reversed phase chromatography (HPLC). Inhibitor B is a gamma-lactam compound and inhibitor 2234 is a beta-lactam.