Cycloheximide-Resistant Glycosylation in L Cells Infected with Chlamydia psittaci

L cells (mouse fibroblasts), uninfected and infected with the meningopneumonitis strain of Chlamydia psittaci, were labeled with [(14)C]glucosamine, and their membranous organelles were separated by isopycnic equilibrium centrifugation of whole cell homogenates on discontinuous sucrose gradients. Glycosylation of host membranes continued throughout the infection. Cycloheximide almost completely inhibited glycosylation in uninfected L cells, but it only partially inhibited the process in infected host cells. Cycloheximide-resistant glycosylation of membrane fractions with [(14)C]glucosamine increased as the infection proceeded and was probably due to the action of chlamydial enzymes. Modification of host membranes by glycosylation may play a role in the natural development of chlamydial infections.