
mammalian cell cultures contaminated with
pleuropneumonia-like organisms
ii. effect of pplo on cell morphology in established
monolayer cultures
the occurrence of cytopathogenic changes in monolayer cultures of
pplo-contaminated mammalian cells has been shown to be related to
deficiency of arginine in the medium.  the same effects were seen when the
cell culture medium was depleted by pplo prior to application to pplo-free
cell cultures even though viable pplo were no longer present.  the fact that
the same picture resulted in the absence of pplo when either arginine or
glucose were omitted from the medium would indicate that, while the defi-
ciency created under the conditions described was specific, the cellular
changes could as well be the result of omission or depletion of other mam-
malian cell growth requirements.  the importance of surveillance of cell
lines for the presence of pplo to avoid misinterpretation of cytopathogenic
effects was stressed.
