INFLUENCE OF OSMOTIC PRESSURE ON SPORULATION BY BACILLUS SUBTILIS

Studies on the physiology of bacterial endospore formation have in many cases involved the addition of one or more compounds to a basal medium, and a determination of the effect of these upon the percentage of cells appearing as spores. The consequences, so far as the spore crop is concerned, of the addition of electrolytes (Fitz-Gerald, 5; Fabian and Bryan, 3), fermentable carbohydrates (Esty, 2; de Smidt, 7), vapors of fat solvents (Michailowsky, 6), antiseptics, and many other compounds have been studied by this method. Among the bacteria, forms can be found which are more resistant to great changes in osmotic pressure than are any other forms of life (Falk, 4). Many species of bacteria, however, in common with other plants and animals, are readily affected by changes in the osmotic pressure of their menstruum (Curran, 1). It is well known that certain physical properties of a medium may influence the degree of endospore formation occurring within that medium. According to our best knowledge, little or no work has been done to determine the influence of osmotic pressure on sporulation. Studies involving the addition of materials of small molecular size could be more easily interpreted if there were available more definite knowledge of the effect of osmotic pressure on spore formation. The present work was undertaken to determine whether osmotic pressure is a factor sufficiently important to warrant consideration in future studies of bacterial sporulation.