The effects of four mercury compounds on the generation time and cell division in Tetrahymena pyriformis, WH14

Abstract

The effects of four mercuric compounds (HgCl 2, phenyl mercuric acetate, ethyl mercuric chloride, and methyl mercuric chloride) on the generation time of Tetrahymena pyriformis have been investigated. HgCl 2 is the least toxic of the four compounds. It causes an increase (5–150%) in the generation time between concentrations of 1.5–5.29 mg/l. Similar observations for phenylmercuric acetate, ethylmercuric and methylmercuric chloride were made at concentrations of 0.022–0.54 ml/liter, 0.04–0.3 mg/liter and 0.04–0.140 mg/liter, respectively. Preliminary observations from experiments that used 2-mercaptoethanol to ameliorate the toxicity of organomercurials suggest that thiol groups are the target sites. The concentrations of each of the four mercurials that cause a 100% increase in the generation time are 1.6 × 10 −5 m, 1.3 × 10 −6 m, 7.4 × 10 −7 m, and 5.6 × 10 −7 m, respectively. Interaction of organomercurials with microtubule proteins is discussed as a possible mechanism for inhibition of cell division.