Cell Wall Synthesis by Chlamydia psittaci Growing in L Cells

Abstract

Biochemical events accompanying changes in structure and behavior of the cell walls of Chlamydia psittaci strain 6BC during its developmental cycle in L cells (mouse fibroblasts) were studied by measuring at short intervals the effect of d -cycloserine and penicillin G on incorporation of labeled intermediates into acid-insoluble fractions of infected L cells in which host incorporation had been inhibited by cycloheximide and into intact chlamydial cells and cell walls separated from the infected L cells. d -Cycloserine enhanced the incorporation of 14 C- l -alanine at all times in the developmental cycle, but the incorporation of 14 C- l -lysine was always inhibited. In parallel experiments, penicillin G had no effect on incorporation of any of these intermediates, but when infected L cells incorporated 14 C- l -alanine in the presence of penicillin G, the labeled alanine was released more rapidly in the subsequent absence of the antibiotic than in its continued presence. When either penicillin G or d -cycloserine was present throughout the developmental cycle, C. psittaci continued to synthesize deoxyribonucleic acid and protein, but at less than normal rates.