Mycocin production in Cryptococcus aquaticus

Double-stranded RNA viruses of about 35 nm in diameter were isolated from a mycocin-secreting strain of Cryptococcus aquaticus. A derivative of this strain, lacking small dsRNA, was non-mycocinogenic and sensitive to its own toxin. The killing pattern of this mycocin was restricted to some species of the Cystofilobasidiales clade. Despite the differences in genome size of dsRNA viruses in mycocinogenic strains of Cryptococcus aquaticus, Cystofilobasidium sp. CBS 6569, Cystofilobasidium bisporidii, Cystofilobasidium infirmominiatum, Trichosporon pullulans and Xanthophyllomyces dendrorhous and killing patterns of their mycocins, the viral genomes showed homology in hybridisation experiments.

Isolation of dsRNA-associated VLPs from the strain Cryptococcus hungaricus CBS 6569

Double-stranded RNAs (dsRNAs) with molecular masses 1.7 and 5.0 kbp, respectively, were isolated from the strain Cryptococcus hungaricus CBS 6569. The dsRNAs were copurified with eicosahedric virus-like particles, 29 nm in diameter. This strain produced a protease-sensitive 'toxin' which inhibited the growth of strain C. hungaricus CBS 4214. The toxin had maximum activity at pH 3.7. The highest toxin amount was attained after a culture period of four days.