Effects of temperature on the frequency of sister chromatid exchanges (SCEs) in peripheral blood lymphocytes of man and muntjac.

The incidence of sister chromatid exchanges (SCEs) and cell proliferation kinetics have been studied in peripheral blood lymphocytes of man and muntjac grown at 33 to 44 degrees C to gain insight into SCE formation. The frequency of SCEs increased as a function of growth temperature. At a given temperature, however, the frequency of SCEs varied with the sampling times; the early sampled cells showed fewer SCEs than did those harvested late. At 33 degrees C the frequency of SCEs was lowest and there was a marked delay in cell-cycle progression. The number of SCEs was maximum at 40 degrees C in human and 42 degrees C in muntjac. Cell proliferation was markedly affected at higher temperature and 44 degrees C was found to be intolerable for lymphocytes of both the species. It is proposed that certain temperature-dependent enzyme(s) associated with DNA replication kinetics may be involved in the formation of SCEs.