Growth of the fungus Geomyces pannorum under anaerobiosis

Abstract

Fungi of the genus Geomyces are eurytopic organ� isms with a broad species distribution area. It is rea� sonable to study the adaptive capabilities of fungal cul� tures in members of the same microbial species exist� ing under drastically different environmental conditions. In our case, these are cryopegs of the Kolyma lowland and the soil of Central Russia. Cry� opegs are supercooled saturated salt solutions charac� terized by a constant temperature (from –10 to ⎯15°C) and total mineralization of 60–300 g/l [1, 2]. Thus, water remains unfrozen and is under anaerobic conditions (Eh from –56 to –240 mV) [3]. The meta� bolic status of mycelial fungi under deep anaerobiosis combined with the low temperature and high salinity of the environment remains unknown; it is, however, highly important to determine the mechanism respon� sible for the preservation of the viability of fungal organisms under such extreme conditions. The goal of the present work was investigation of the metabolic capabilities of two Geomyces pannorum strains, specifically, of their ability to grow and form the fermentation products in the absence of oxygen in the media with different redox potentials (Eh). The objects of research were the strain VKM FW�2241 iso� lated from cryopeg water in permafrost deposits of the Arctic [4] and the strain VKM F�3808 isolated from the hair of bank vole Cletrionomys glareolus (Tver oblast, Russia). The partial 18S rRNA gene sequences of both strains are deposited in GenBank under acces� sion numbers AY873966 and AY873968, respectively. The strains under study were grown on a modified Czapek medium [5]. In the experiments with different reducing agents, ammonium sulfate was added to the