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Reprinted from Journal of General Microbiology, Vol. 23, October 1960, pp. 295-300., The yeast flora of moss from Granite Harbour and of soils from Wright Dry Valley in the McMurdo Sound region of Antarctica was examined. There were 75,000 yeasts/g. on the moss; species recovered were Cryptococcus laurentii, C. albidus and Rhodotorula minuta. Yeasts were isolated from 8 of the 12 soil samples in numbers up to 5000/g. Strains of Candida scottii, whose maximum growth temperature was c. 15°, were the predominant soil yeasts.

Reprinted from Journal of General Microbiology, Vol. 25, 1961, pp. 113-117., Yeasts belonging to the genera Candida and Trichosporon have been isolated in small numbers from the rumen of fistulated cows. Similar yeasts were not found on samples of feed material. The yeasts present fell into two groups dependent on the diet of the cow from which they were isolated.

Reprinted from the Journal of General Microbiology, Vol. 17, no. 3, December 1957, pp. 678-688., A series of comparative studies was made of soil yeasts in a yellowbrown earth originally under forest but now under pasture. Of six solid acid media used for primary isolations, an agar medium containing 4 % (w/v) glucose and 1 % (w/v) peptone gave the highest yeast counts. Two soil-extract agars and a modified Czapek-Dox agar gave slightly lower counts; a third soil-extract agar inhibited all but one yeast species and gave a much decreased count. The addition of a surface active agent to glucose peptone agar did not increase the count. Acid broth enrichment cultures gave a distorted picture of the species pattern shown by primary cultures on solid media. Prolonged mechanical shaking of soil dilutions before culturing, and the addition of a surface active agent to the diluent did not affect the yeast pattern seen, quantitatively or qualitatively.

Reprinted from the Journal of General Microbiology, Vol. 18, no. 1, February 1958, pp. 269-272., A new species of Candida was isolated from sphagnum litter overlying a peat bog. It was non-fermenting and assimilated glucose, sucrose, maltose, lactose, galactose and potassium nitrate. The proposed name is Candida muscorum. A new Rhodotorula species, which it is proposed to name R. graminis, was isolated from the leaves of pasture grasses. Cultures on solid media were reddish pink and fluid in consistency. Glucose, sucrose, galactose and potassium nitrate were assimilated.

Reprinted from the Journal of General Microbiology, Vol. 20, No. I, February 1959, pp. 13-23., An investigation has been made of some physiological properties of yeasts from soil and from the leaf surfaces of pasture plants. Almost all the species tested could use cellobiose, and the majority could synthesize growth factors and use a range of organic acids as carbon sources. Some species, including all the pigmented ones examined, could use aromatic compounds as carbon sources. A few species could liquefy gelatin. Only two were able to degrade pectin completely under the conditions used. Almost all could grow within a wide range of hydrogen ion concentrations and at osmotic pressures of at least 30 atmospheres. Ability to survive desiccation varied greatly. Only one species showed any ability to grow at low oxygen tensions. No marked or consistent differences could be seen between soil and leaf yeasts. As both groups are competent to grow in substrates which supply low concentrations of complex foodstuffs, it seems likely that antagonistic factors originating from other members of the soil arid leaf populations are responsible for keeping the two floras distinct.

Reprinted from the Journal of General Microbiology, Vol. 19, no. 3, December 1958, pp. 581-583., An undescribed species of Torulopsis has been isolated from pasture grass leaves. It does not ferment sugars and assimilates glucose, sucrose, maltose, lactose, galactose and potassium nitrate. It is distinguished from Torulopsis aeria by the oval shape of its cells, mucoid cultures on solid media, and the ability to liquefy gelatin rapidly. It is proposed to name it T. ingeniosa.