Abstract: | The unbalanced growth forms (UGF), also known as heteromorphous or pleomorphous forms, of salmonellae were obtained under the action of penicillin, homologous antiserum in combination with complement and lysozyme, as well as ultraviolet radiation. The effect of these factors was studied after their momentaneous action and in successive passages. The viability of UGF was determined in terms of colony-forming units. The appearance of UGF was induced by penicillin, a complex of immune substances and ultraviolet radiation, yet the action of two latter factors irreparably damaged most of the cells. The formation of UGF, showing stability in prolonged passages and capable of transformation into L-forms, occurred only under the influence of penicillin. Elementary bodies appeared in UGF, both capable and incapable of transformation into L-forms after successive passages. In the viable part of the UGF population obtained under the action of all the above factors damages in the peptidoglycan layer of the cell wall and, partly, in the cytoplasmic membrane, as well as disturbances in the process of cell division, linked with these cell elements, were observed. |