PubMed · 13363772
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R W BENHAM. 1956. The genus Cryptococcus.. https://doi.org/10.1128/br.20.3.189-201.1956
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During our screening of amylolytic microorganisms from Brazilian fruits, we isolated a yeast strain classified as Cryptococcus flavus. When grown on starch-containing medium this strain exhibited the highest amylase production after 24 h of cultivation. The extracellular amylase from C. flavus was purified from the culture broth by a single step using chromatography on a Sephacryl S-100 column. The enzyme was purified 16.14-fold with a yield of 50.21% of the total activity. The purified enzyme was a glycoprotein with an apparent molecular mass of 75 and 84.5 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, respectively. The enzyme lost approximately 50% of the molecular mass after treatment with glycosidases. The major end products of starch, amylose, amylopectin, pullulan and glycogen were maltose and maltotriose. The K(m) value for the pure enzyme was 0.056 mg ml(-1) with soluble starch as the substrate. Enzyme activity was optimal at pH 5.5 and 50 degrees C. The enzyme retained 90% of the activity after incubation at 50 degrees C for 60 min and was inhibited by Cu(2+), Fe(2+) and Hg(2+).
The effects of the soil yeasts Rhodotorula mucilaginosa, Cryptococcus laurentii and Saccharomyces kunashirensis on the arbuscular mycorrhizal (AM) fungus Glomus mosseae (BEG 12) was studied in vitro and in greenhouse trials. The presence of yeasts or their soluble and volatile exudates stimulated the percentage spore germination and hyphal growth of G. mosseae. Percentage root length colonized by G. mosseae and plant dry matter of soybean (Glycine maxL. Merill) were increased only when the soil yeasts were inoculated prior to the AM fungus. Higher beneficial effects on AM colonization and plant dry matter were found when the soil yeasts were inoculated as an aqueous solution rather than as a thin agar slice. Although soluble and volatile exudates of yeasts benefited the AM symbiosis, their modes of action were different.
A novel species of the genus Cryptococcus was isolated from sediment collected on the deep-sea floor of Suruga Bay, Japan. Nucleotide sequences of 18S rDNA, internal transcribed spacers, 5.8S rDNA and the D1/D2 region of 26S rDNA of strain SY-260(T) suggested affinities to a phylogenetic lineage that includes Cryptococcus luteolus. Comparisons of the rDNA sequences of each region clarified that strain SY-260(T) is related distantly to Bullera coprosmaensis and Bullera oryzae, but is distinct at the species level. As ballistoconidia and sexual reproduction were not observed in strain SY-260(T), this strain is described as Cryptococcus surugaensis sp. nov. (type strain, SY-260(T)=JCM 11903(T)=CBS 9426(T)).