[Analysis of the morphological variants arising during S <--> R dissociation in Bacillus thuringiensis]

Physiological, biochemical, and serologic characteristics of 24 clones of R variants spontaneously emerging from the wild type strain of Bacillus thuringiensis biotype dendrolimus and of 25 clones of S revertants resulting from the plating of one of the R variants are investigated. It is shown that the efficiency of spore formation is the only characteristic among those investigated which correlated with colony morphology of the S or R type. All R variants were oligo- or asporogenous; they usually differed in characteristics of adaptive importance. The process of spore formation was restored in the S revertants, but they differed both from the wild type and from each other. In contrast to the initial forms, R variants and S revertants most commonly exhibited the capability to ferment sucrose. Based on the data obtained, an assumption was made concerning the nature of dissociation in the strain under investigation.