Demonstration, with the Electron Microscope, of a Nucleus in Bacillus mycoides Grown in a Nitrogen-free Medium

Abstract

When the endospores of B. mycoides, C2, are washed with sterile, dist. water and heavily inoculated into a N-free medium, many germinate and gradually use up their supply of ribonu-cleic acid. The germ cells and subsequent generations of vegetative cells are transparent to electrons even at 50 or 30 kv. and show 2 types of opaque bodies. Bodies of the 1st type are relatively large and highly opaque; they show evidence of division and are totally enclosed in the forespore; they do not seem to divide by simple constriction; these are the nuclei of the cell. The bodies of the 2d type are smaller and very thin; they consist of beaded threads and granules located in the cytoplasmic membrane; they do not, visibly, take part in the formation of the endospore; there is evidence that they are endowed with synthetic power and that they are involved in the formation of cross plates at the time of cell division.