Kluyveromyces osmophilus, a new yeast species
In 1962 Dr. R. ANTOINE of Mauritius sent a number of yeast strains isolated from sugar for identification to the Yeast Division of the Centraalbureau voor Schimmelcultures at Delft. One of these strains is considered to belong to a new species for which the name Kluyverornyces osmophilus is proposed. It will be described in the following part. This yeast strain was conspicuous by forming oval to reniform spores which were easily liberated from the ascus. When first studied, sporulation was abundant. The picture of the spores in this paper. (fig 2) is an electron micrograph of ultra-thin sections of a preparation fixed at that time with osmic acid and uranyl acetate according to RYTER et al. (1958). Unfortunately, the sporulating ability has been lost after maintaining the yeast for two years on malt agar. The yeast, grown on malt agar, was investigated according to the methods of WICKERHAM (1951) and of LODDER & KREGERVAN RIJ (1952). As regards the fermentation and assimilation reactions some remarks can be made. Fermentation of a 2% (w/v) glucose solution in a Durham tube was rather slow, i.e. the insert tube was filled up with gas after 10--14 days' incubation at 25 ° C. A 10% glucose solution gave the same result after 5--7 days, while a 30% glucose solution had a gas-filled insert tube after 5 days. Apparently, in solutions with a higher sugar concentration the fermentation rate was high at an earlier period. The assimilation test with the auxanographic method gave positive results for glucose and galactose only. The assimilation test in a synthetic liquid medium with glucose as the sole source of carbon in a concentration of 0 .50, read after one week at 25 ° C, show-
The emendation of the genusKluyveromyces v. d. Walt
The genusKluyveromyces has been emended to include species forming 1 – 4 crescentiform, reniform, prolate ellipsoidal or spheroidal ascospores.Fourteen species have been assigned to the emended genusKluyveromyces.
Yeasts Isolated from Drosophila and From Their Suspected Feeding Places in Southern and Central California
In 1948 Dobzhansky expressed the view that yeasts are important in understanding some of the forces of natural selection to which popula? tions of Drosophila flies are exposed. Since then there has been an intense interest in the relation of yeast to Drosophila in nature. Al? though certain aspects of this relationship have been studied, information pertaining to the taxonomy of yeast occurring in Drosophila flies is quite limited. Chatton (1913) reported the occurrence of Coccidiascus ligeri as an intestinal parasite of D. funebris. In 1944 Dobzhansky and Epling iso? lated a yeast, which they termed 5\ farinosus (syn. Pichia farinosa), from the crops of D. pseudoobscura. Later, at Dobzhansky's suggestion, Wagner isolated some yeasts from the crops of D. pseudoobscura col? lected at Pinon Flats in the San Jacinto mountains in Southern Cali? fornia. These were identified by Mrak (unpublished data) as species of the genus Zygosaccharomyces. Wagner (1944) also isolated but did not identify 8 types of yeast from Opuntia fruits and demonstrated that the yeasts had different nutritional qualities for certain species of Dro? sophila. Buzzati-Traverso in 1950 3 isolated 15 cultures of Torulopsis from Drosophila flies trapped in the Po Valley in Italy. Hedrick and Burke (1950) and Hedrick and Burke (1952) identified 17 yeasts iso? lated from crop contents, feces, and immediate substrates of two species of flies (D. crucigera and D. pilimana) collected in Hawaii. Shehata and Mrak (1952) compared the intestinal yeast floras of successive populations of Drosophila. In this study emphasis was placed on the relation of the type of yeast to the population cycles of the differ? ent chromosomal types of Drosophila pseudoobscura rather than on the taxonomy of the yeast isolated. In somewhat similar work da Cunha et al. (1951) demonstrated that certain yeasts isolated from the crops