Search

Reinvestigation of the three strains currently classified asTorulopsis domercqii has established that two of the strains are representative of a homothallic, ascogenous species. Electron microscopy has confirmed that the ascospores of this species are elongate to oblong apparently with a rugose spore wall. Apart from normal budding, budding on broad base was also observed. As the species cannot be accommodated in the existing genera of the Saccharomycetaceae, it is redescribed as the type species of a new genus. Descriptions of the new taxa are given.

The yeast species previously described asPichia robertsii v. d. Walt has been transferred to the new genusWingea. The diagnosis for the genus is given.

The new genusDekkera is proposed for the classification of ascosporogenous yeast strains which have hitherto been classified as species of the genusBrettanomyces.

To understand an organism completely, it is necessary to have knowledge of both its structure and life history. With many microorganisms that affect man, either beneficially or harmfully, an exact knowledge of the life history and structure of the organisms is essential if either control is to be exercised or the organisms are to be utilized to best advantage. This chapter presents an experiment to examine yeast, an organism produced on a very large scale throughout the world for baking and brewing, as a source of biochemicals and as a foodstuff. Yeasts are fungi belonging to the class Ascomycetes. Some are grouped under the Order Saccharomycetaceae, that is, yeasts that reproduce asexually by budding—for example, brewers' or bakers' yeast Saccharomyces cereviseae . They are essentially unicellular organisms that occur naturally on the surface of fruits, although it is thought that they have arisen from mycelial forms of fungi.

The yeast species previously described asSaccharomyces elongasporus Recca et Mrak has been transferred to the new genusLodderomyces. The diagnosis for the genus and standard description of its type species are given.

Of the many genera of the family of Saccharomycetaceae , 1 comparatively few play an etiologic role in dermatomycoses. The most important and the most frequent dermatologic lesion caused by yeasts is a deep infection first described by Gilchrist in 1914, and commonly known as blastomycosis. This dermatomycosis is caused by the genera Saccharomyces ( Blastomyces ), Cryptococcus and Coccidioides . The peculiar warty lesions and abscesses that characterize this affection are well known and need not here be described. On the other hand, yeast infection may occur superficially. Thrush is the best known instance. Other instances of less frequent occurrence will be pointed out later, with particular reference to an infection known as intertrigo saccharomycetica, cases of which are herein reported. Thrush, caused by Oidium albicans and certain species of Monilia , occurs as a white or creamy adherent membrane on an erythematous base, most frequently on the oral mucous membranes of infants. It