Reproductive Processes in Proteus Cultures. ∗

Abstract

Summary

The complex reproductive processes formerly observed in certain Gram-negative bacteria have also been observed in Proteus cultures. In this species they presented several distinctive characteristics. The large bodies in every case previously studied were produced by gradual swelling of the bacteria. In Proteus they are produced by a process known as “plasmoptysis.” The large bodies so produced possess similar physical properties and show reproductive processes similar to those formed in other species by swelling of the bacteria.

Another characteristic of Proteus is that the bacteria from which the large bodies develop differ considerably from the bacteria usually present in the culture. Large bodies develop only from spreading filaments actively motile on solid media. In almost every culture these filaments produce an occasional large body, and most of them are transformed into large bodies when the spreading halo of one strain meets the spreading halo of another appropriate strain. The large bodies so produced are viable and within a short time are transformed into regular bacteria. Exceptionally they produce the L type of growth. There is a great variation in the reaction of different strains to each other.

The spreading filaments show a tendency to “plasmoptysis” and production of large bodies under various adverse conditions, for example, when they are subjected to refrigeration or when they are transferred into tap-water or into broth containing HgCl. The large bodies produced by refrigeration are apparently fully viable. Those produced by tapwater are only occasionally viable, and when they germinate they usually produce L type colonies. Large bodies produced by HgCl₂ are not viable. The difference in viability constitutes an important difference between the large bodies produced by the interaction of the 2 strains and by refrigeration on one hand, and by toxic influences on the other hand.