A survey of the early literature on aberrant bacteria
has shown that what are now considered to be L forms or
cell wall defective variants were well recognised entities
long before Klieneberger drew attention to the presence of
these microbial variants in the cultures of Strcptobacillus
moniliformis. The review of the more recent interdisciplinary investigations carried out on L forms and
other wall defective microbial variants has revealed
that there is still a considerable lack of information
on their biological and pathogenic properties.
Investigations carried out on ten strains of
Salm. gallinarum have shown penicillin, glycine and a
number of other substances used in the present work are
capable of inducing L transformation in this bacterial
species. Considerable variations occurred between the
strains in their ability to respond to L transformation.
Isolaxes from more recent clinical material were found to
undergo L transformation more readily than the standard
laboratory strains. Likewise it was easier to induce
L transformation in the smooth than the rough strains of
Salm. gallinarum. The ability of field isolates to
undergo spontaneous L transformation without the aid of
any known incitant is believed to be a new finding that
has not been recorded in the Salmonella group of
A number of cultural and environmental factors
that aid in the transformation and propagation of these
L forms were investigated and discussed. All ten
strains of Salm. gallinaruia produced only an unstable
L growth on a solid hypertonic medium. A hitherto
unrecorded finding is that in the two laboratory strains
which, though unable to produce stable L growth, were
able to do so in a liquid medium; furthermore the
elimination of the serum requirement for stabilisation
liquid medium is hoped will provide the basis
for the future immunological and biochemical characterisation of the L forms of Salm. gallinarum.
Biochemical investigations on some of the L forms
and revertants arising from these altered variants showed
that they resembled in general their parental forms
denoting absence of mutational changes.
Filtration studies have revealed that not all elements
in L cultures are filterable.
Investigations on the ultrastructure of L forms of
Salm. gallinarum show that the inducing agents used in
the current studies bring about varying degrees of cell
wall damage resulting in the production of cell wall
defective variants not only varying in their sizes
but also in the amount of cell wall layers retained.
The pathogenic properties exhibited by the ions table
L forms of Salm. gallinarum were shown to be due to their
reversion to the vegetative forms in vivo and the death
of the experimental host was ascribed to the endotoxic
properties of the organism.