The Significance of Pleomorphism in Bacteroides Strains

Abstract

A few bacterial species axe characterized by a peculiar pleomorphism, consisting in the gradual swelling of the bacteria into large fusiform or round bodies. A similar transformation occurs in a few exceptional strains belonging to the common species under normal conditions of cultivation. Sublethal doses of lithium, calcium, chromium, mercuric salts and penicillin often produce similar forms. Glycin seems to be very effective in this respect (Gordon and Gordon, 1943). Observations described in previous papers (Dienes, 1942) indicate that the large bodies, if they are appropriately transplanted, will germinate in certain cultures. Usually they do not reproduce bacteria of normal shape, but a peculiar granular growth which was discovered by Klieneberger in cultures of Streptobacillusmoniliformis and named L1 (Klieneberger, 1935). A similar germination of the large bodies was observed in some strains of Escherichia coli, Hemophilus influenzae and BaciUus funduliformis. An L type of growth was observed also in cultures of Neisseria (Dienes, 1940) and of a Flavobacterium. The large bodies germinated, according to our observations, only in spontaneously pleomorphic strains, not in cultures made pleomorphic by toxic influences. It was pointed out in the above-mentioned paper (Dienes, 1942) that the L type of growth is not the only direction in which the large bodies develop. Sometimes they reproduce bacteria of regular shape and size. One of the authors observed this process in E. coli (Dienes, 1939) and recently in a clear form in a strain of Streptobacius

Pleomorphism of fusobacteria isolated from the cockroach hindgut

“…The development of large bodies from normal rods of F. i'arium followed by the regeneration of bacillary forms by fragmentation of the large body is somewhat similar to observations made with F. necroplhoruln ("Bacteroides filnduliformiss") (11,22). Large bodies were reported to have a twofold potential, i.e., they produced ordinary bacteria or a peculiar pleomorphic L-type growth.…”

“…Organisms thought to be Fusobacterium necrophorum ("B. funduliformis," "S. necrophorus") were described as having bulbous enlargements that formed round bodies. These segmented to yield new rod-shaped cells (11,22). The DNA base composition of the rods and the large body forms was the same (12).…”

PROTOPLASTS AND L-TYPE GROWTH OF ESCHERICHIA COLI

“…Other roles that have been assigned to L forms are: an aberrant haplophase (Dienes, 1946); sexuality (Dienes and Smith, 1944;Klieneberger-Nobel, 1950); a resistant stage analogous to spores (Tulasne, 1955); a phase of regeneration or rejuvenation, possibly also correlated with sexuality (Klieneberger-Nobel, 1951). There is no indication that L growth is associated with deep-seated changes in genetic makeup; in any case, the vegetative phase of E. coli and probably other bacteria is normally already haploid.…”

Controversial Aspects of the Morphology of Pplo*

“…Despite this, during twenty years I have observed only one case in which it appeared probable that the bacteria were present in the cells of a pathological process in the L form. 2 The fact that L forms of S. moniliformis were cultivated directly from rats or humans does not necessarily indicate that they were present in the specimen in such form.…”