Abstract
The effect of folate starvation on the biochemical constitution and morphology of Lactobacillus casei was studied by growing cultures in different concentrations of folic acid. Folate starvation leads to a marked reduction in the amount of DNA synthesized, a large increase in the average cell length and a striking loss of viability. In addition, extreme folate starvation leads to small reductions in the amount of RNA and protein synthesized. The similarities between folate deprivation in L. casei and in man suggest that the bacterial system may provide a convenient model of the condition in humans.