Reversibility of heat shock in Chlamydia trachomatis.

The heat shock effect on chlamydia development was studied. We report here that the reversibility of the heat shock response did not depend on the stage of chlamydial morphogenesis at which transfer to high temperature occurred, and the infectivity of the particles produced was not affected significantly, so long as the heat shock exposure was not prolonged. Exposure to heat shock for more than 9 h resulted in stagnation of the growth cycle, appearance of aberrant reticulate body particles and loss of infectivity. SDS-PAGE analysis of proteins synthesized under prolonged heat shock showed increased relative abundance of heat shock proteins in common with other procaryotic organisms.