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Cycloheximide-resistant glycosylation in L cells infected with Chlamydia psittaci
Abstract:
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.
Insights
Chlamydia psittaci infection alters host cell glycosylation. Infected mouse cells show increased resistance to cycloheximide, suggesting chlamydial enzymes modify host membranes during infection.
Area of Science:
- Cell Biology
- Microbiology
- Biochemistry
Background:
- Chlamydia psittaci is an obligate intracellular bacterium.
- Host cell membrane modification is crucial for pathogen survival and replication.
- Glycosylation is a key post-translational modification of proteins and lipids.
Purpose of the Study:
- To investigate the impact of Chlamydia psittaci infection on host cell membrane glycosylation.
- To determine if chlamydial enzymes contribute to host membrane modification during infection.
Main Methods:
- L cells (mouse fibroblasts) were infected with Chlamydia psittaci.
- Cells were labeled with [(14)C]glucosamine to track glycosylation.
- Membranous organelles were separated using isopycnic equilibrium centrifugation.
- The effect of cycloheximide on glycosylation was assessed in infected and uninfected cells.
Main Results:
- Host membrane glycosylation continued throughout Chlamydia psittaci infection.
- Cycloheximide significantly inhibited glycosylation in uninfected cells but only partially in infected cells.
- A cycloheximide-resistant glycosylation process increased with infection progression.
- This resistance suggests the involvement of chlamydial enzymes in modifying host membranes.
Conclusions:
- Chlamydia psittaci infection alters host cell glycosylation patterns.
- Chlamydial enzymes likely contribute to the modification of host membranes.
- Host membrane glycosylation may play a role in the pathogenesis of chlamydial infections.