Choline deficiency induced by Mycoplasma fermentans enhances apoptosis of rat astrocytes

A choline uptake system accumulating free choline in an energy-dependent pr ocess is described in Mycoplasma fermentans. The uptake system has a K-m of 2.2 x 10(-5) M and a V-max of 0.15 nmol 10 min(-1) mg(-1) cell protein and the choline incorporated could be recovered in the soluble fraction as fre e choline, phosphorylcholine and CDP-choline. Choline accumulation by M. fe rmentans resulted in a marked choline depletion of the growth medium. The c holine depletion of an astrocyte cell culture induced by M. fermentans was associated with the apoptotic death of the cells. Apoptosis was not obtaine d with heat-inactivated mycoplasmas and could be reversed by the addition o f free choline to the growth medium. (C) 2001 Federation of European Microb iological Societies. Published by Elsevier Science B.V. All rights reserved .