Investigation of the Existence and Nature of Reserve Material in the Endospore of a Strain of Bacillus mycoides by an Indirect Method

Abstract

The endospores of strain C2 of B. mycoides washed 5 times in dist. water are able to germinate normally in a soln. of glucose (0.2 g. in 100 ml. of water) without addition of a source of N. When this glucose soln. is buffered with potassium phosphate (02 g.) at a pH of about 7, germination is followed by growth and sporu-lation. There is no tendency for germination in a soln. of KNO3 (0.2 g. + 100 ml. of water) with or without potassium phosphate (023 g.) unless glucose is added. It is concluded that endospores of the strain investigated contain relatively large amts. of a N-containing reserve material not suitable as a source of energy, and that they contain no other reserve material for that purpose. Endospore suspensions in solns. of glucose or, particularly, glucose + KN03, reach a min. pH much below that reached by vegetative cells in similar solns. New evidence is given that endospores are formed by healthy cells facing starvation, and the question of a minimum conc. of nutrients for sporulation is discussed.