Subcellular effect of cytochalasin B and dimethylsulfoxide on Paramecium aurelia.

Paramecium aurelia syngen 4, stock 57 (sensitve) cultivated in Cerophyl infusion were exposed to cytochalasin B (CB) and dimethylsulfoxide (DMSO), the solvent for CB, to distinquish between the effects of these agents on a cellular system. DMSO significantly inhibited survival, fission rate,, [3H]leucine incorporation, and cell size. CB-treated cells generally and slower division and poorer survival rates than cells exposed to the equivalent DMSO concentration, although the [3H]leucine incorporation was generally greater at the lower CB concentrations than for DMSO alone. As seen by electron microscopy and a new glycerination technic for observing polysomes, DMSO caused nuclear (nucleolar, chromatin) abnormalities as well as membrane degradation and polysomal breakdown: CB caused the formation of aberrant membrane structures and ribosomal tetramers, crystals, and tubes.