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Changes in liver and L-cell plasma membranes during infection with Coxiella burnetii
Abstract:
Changes in plasma membrane proteins of guinea pig liver and L-929 cells were studied during infection with Coxiella burnetii. Polypeptide species resolved by disc polyacrylamide gel electrophoresis with sodium dodecyl sulfate showed quantitative but no qualitative differences between uninfected and infected samples. When the O'Farrell technique of isoelectric focusing, followed by sodium dodecyl sulfate-slab gel polyacrylamide gel electrophoresis, was employed, additional polypeptides were resolved. Livers and L cells were labeled with [3H]-glucosamine. Infected livers incorporated less [3H]glucosamine in the membrane proteins than uninfected material, presumably indicating lower glycoprotein levels. Infected L-cell membranes incorporated greater amounts of [3H]glucosamine, and also were labeled to a greater extent than uninfected membranes, employing the [125I]lactoperoxidase technique. Uninfected L cells showed a greater agglutinability with concanavalin A than did infected cells. Infected livers had much greater levels of cyclic adenosine 3',5'-monophosphate. The data indicate changes in plasma membranes as a result of infection. Possible physiological consequences of membrane changes are discussed.
Insights
Coxiella burnetii infection alters cell membranes, affecting protein levels and glycoprotein content in guinea pig liver and L-929 cells. These changes impact cell surface properties and cyclic adenosine 3
Area of Science:
- Microbiology
- Cell Biology
- Biochemistry
Background:
- Investigating the host-pathogen interactions at the cellular level is crucial for understanding disease pathogenesis.
- Plasma membrane alterations are common during microbial infections, impacting cellular functions.
- Coxiella burnetii is an intracellular bacterium known to cause Q fever, a zoonotic disease.
Purpose of the Study:
- To elucidate the changes in plasma membrane proteins of guinea pig liver and L-929 cells upon Coxiella burnetii infection.
- To analyze the impact of infection on glycoprotein content and cell surface characteristics.
Main Methods:
- Utilized polyacrylamide gel electrophoresis (PAGE) with sodium dodecyl sulfate (SDS) for polypeptide analysis.
- Employed isoelectric focusing followed by SDS-PAGE (O'Farrell technique) for higher resolution protein separation.
- Incorporated radiolabeling with [3H]-glucosamine and [125I]lactoperoxidase to assess glycoprotein and surface protein changes.
- Assessed cell agglutinability with concanavalin A and measured cyclic adenosine 3',5'-monophosphate levels.
Main Results:
- Quantitative, but not qualitative, differences in polypeptides were observed using basic SDS-PAGE.
- Advanced techniques revealed additional polypeptides in infected cells.
- Infected livers showed decreased [3H]-glucosamine incorporation (lower glycoproteins), while infected L-cells showed increased incorporation and surface labeling.
- Infected L-cells exhibited reduced concanavalin A agglutinability, and infected livers had elevated cyclic adenosine 3',5'-monophosphate levels.
Conclusions:
- Coxiella burnetii infection induces significant changes in the plasma membrane composition and structure of host cells.
- These alterations include modifications in protein and glycoprotein content, affecting cell surface properties.
- The observed membrane changes likely have physiological consequences for host cell function during infection.