Related Experiment Videos
[Comparative evaluation of Yersinia interaction with HEp-2 cells]
Abstract:
In experiments on HEp-2 cells, the comparative characterization of the mechanism of invasion and the cytotoxic action of a number of Y. pseudotuberculosis strains, serovar 1, and Y. enterocolitica strains 03 and 09 (24 strains newly isolated from human patients and rodents and 5 laboratory strains at different degrees of attenuation) has been made on the basis of data obtained by optical and electron microscopy, as well as by cytoenzymological analysis. As revealed in these experiments, the invasion of Yersinia into epithelial cells and their capacity for intracellular multiplication depend on the cytotoxicity of the bacteria, most pronounced in Y. pseudotuberculosis, serotype 1, considerably less pronounced in Y. enterocolitica 09, and poorly pronounced (or absent) in Y. enterocolitica 03. Cytopathic changes are manifested by vacuolization, the exocytosis (clasmatosis) of the peripheral cytoplasm, impoverishment in organellae, the formation of autophagosomes, the shriveling of the nuclei and the perinuclear cytoplasm, the rounding of the cells and their separation from the glass surface. The development of these changes is accompanied by the increased activity of phosphatases diffusing into the cytoplasm and by the inhibition of cell respiration and dehydrogenase activity.
Insights
Yersinia bacteria invasion into epithelial cells is driven by bacterial cytotoxicity. This cytotoxicity, most potent in Yersinia pseudotuberculosis, influences intracellular multiplication and causes distinct cytopathic effects in host cells.
Area of Science:
- Microbiology
- Cell Biology
- Pathogenesis
Background:
- Yersinia species are significant bacterial pathogens.
- Understanding Yersinia invasion mechanisms is crucial for disease control.
Purpose of the Study:
- To comparatively characterize the invasion mechanisms and cytotoxic actions of Yersinia pseudotuberculosis and Yersinia enterocolitica strains.
- To correlate bacterial cytotoxicity with intracellular multiplication and cytopathic effects.
Main Methods:
- Optical and electron microscopy of infected HEp-2 cells.
- Cytoenzymological analysis of cellular changes.
- Infection assays with various Yersinia strains.
Main Results:
- Bacterial cytotoxicity directly correlates with Yersinia invasion and intracellular multiplication.
- Yersinia pseudotuberculosis (serovar 1) exhibited the highest cytotoxicity, followed by Yersinia enterocolitica 09, and then Yersinia enterocolitica 03.
- Cytopathic effects included vacuolization, cytoplasm expulsion, organelle loss, autophagosome formation, nuclear changes, and cell detachment.
Conclusions:
- Bacterial cytotoxicity is a key determinant of Yersinia's ability to invade and multiply within epithelial cells.
- Distinct cytopathic changes and altered enzymatic activities (increased phosphatases, inhibited respiration/dehydrogenase) are associated with Yersinia infection.