Related Experiment Videos
Hydrolytic enzymes in KB cells infected with poliovirus and herpes simplex virus
Abstract:
Flanagan, John F. (Duke University School of Medicine, Durham. N.C.). Hydrolytic enzymes in KB cells infected with poliovirus and herpes simplex virus. J. Bacteriol. 91:789-797. 1966.-The effect of poliovirus and herpes simplex virus infection on the activity of five hydrolytic enzymes was studied in tissue culture cells of KB type. During the course of poliovirus infection, the activity of beta-glucuronidase, acid protease, acid ribonuclease, acid deoxyribonuclease, and acid phosphatase in the cytoplasm rose to levels two- to fourfold greater than the activity present in the cytoplasm of uninfected cells. The rise in cytoplasmic activity was accompanied by a concomitant decrease in enzymatic activity bound to cell particles. Shift of enzymatic activity from the particulate to soluble state was first detected at 6 hr after poliovirus infection, coinciding with the appearance of new infectious particles and virus cytopathic effect. No net synthesis of these enzymes after poliovirus infection was found. Hydrocortisone added to the culture medium failed to affect either the titer of virus produced in the cells or the release of hydrolytic enzymes from the particulate state. Herpes simplex infection produced minimal alterations in the state of these enzymes in KB cells. It is hypothesized that the breakdown of lysosomes and release of hydrolytic enzymes accompanying poliovirus infection is produced by alterations in cell membrane permeability during the course of virus replication and by the consequent change in the ionic content of the cell sap.
Insights
Poliovirus infection significantly increases cytoplasmic hydrolytic enzyme activity in KB cells, shifting enzymes from cell particles to the soluble state. Herpes simplex virus caused minimal changes, suggesting poliovirus alters cell membrane permeability.
Area of Science:
- Virology
- Cell Biology
- Biochemistry
Background:
- Hydrolytic enzymes play crucial roles in cellular processes.
- Viral infections can significantly alter host cell functions.
- Lysosomes are key organelles containing hydrolytic enzymes.
Purpose of the Study:
- To investigate the impact of poliovirus and herpes simplex virus infections on hydrolytic enzyme activity in KB cells.
- To determine if viral infections induce changes in the localization and synthesis of specific hydrolytic enzymes.
- To explore the potential mechanisms behind observed enzymatic alterations.
Main Methods:
- KB cells were infected with poliovirus and herpes simplex virus.
- Activity of five hydrolytic enzymes (beta-glucuronidase, acid protease, acid ribonuclease, acid deoxyribonuclease, acid phosphatase) was measured.
- Enzyme activity was assessed in both cytoplasmic and particulate fractions.
- Effect of hydrocortisone on viral titer and enzyme release was evaluated.
Main Results:
- Poliovirus infection led to a 2- to 4-fold increase in cytoplasmic hydrolytic enzyme activity.
- Enzymatic activity shifted from particulate-bound to soluble states starting at 6 hours post-infection.
- No net synthesis of these enzymes was detected after poliovirus infection.
- Herpes simplex virus infection caused minimal alterations in enzyme activity and localization.
- Hydrocortisone did not affect viral titer or enzyme release.
Conclusions:
- Poliovirus infection disrupts lysosomal integrity, releasing hydrolytic enzymes into the cytoplasm.
- Alterations in cell membrane permeability during poliovirus replication likely cause the shift in enzyme localization.
- Changes in intracellular ionic content may contribute to lysosomal breakdown.
- Herpes simplex virus has a limited effect on the hydrolytic enzyme status in KB cells.