Ultrastructural studies of cell-virus interaction in reptilian cell lines. IV. Effects of chloramphenicol and ethidium bromide on VSW cell mitochondria and associated virions.

Structural effects of chloramphenicol (CAP) and ethidium bromide (EB) on VSW cell mitochondria and intramitochondrial virions (IMV) have been studied on a comparative basis by thin-section electron microscopy. CAP-treated cells show a wide variety of mitochondrial alterations, frequently involving swelling of the organelle and loss of cristae orientation. IMV are generally severely disrupted, particularly in peripheral regions. In such configurations, strand-like material radiates in a spokelike fashion from the shell zone to adjacent cristae-matrix area. EB-treated cells also display considerable mitochondrial distortion evidenced primarily by the formation of small, localized multimembrane regions. IMV exposed to EB, however, are less structurally damaged than CAP-treated ones. The relative incidence of IMV production is enhanced approximately fourfold in EB-treated cells compared to CAP-treated ones, suggesting that virion synthesis may be under nuclear, rather than mitochondrial, control.