The Stability of Mycoplasma mycoides

SUMMARY: The morphology of Mycoplasma mycoides was well preserved after washing and suspension in buffered 0.4 M-sucrose solutions, but the survival of viable particles was no better, and the loss of ultraviolet (u.v.)-absorbing substances and the decrease of turbidity was no less than in hypotonic solution (0–01 M-tris HC1 or 0.01 M-Na2HPO + KH4PO4). The addition of Mg2+, Ca2+, spermidine or spermine (increasing order of activity) decreased the decrease of turbidity and loss of u.v-absorbing substances. Ca2+ and Mg2+, but not spermine, increased the degree of survival of viable particles. Ethylenediaminetetra-acetate (EDTA; 0.01 M) increased the loss of u.v.-absorbing substances, and decreased the turbidity and degree of survival. Ca2+, Mg2+ and spermine annulled the effects of EDTA on loss of u.v.-absorbing material and on the turbidity, but only Ca2+ prevented the lethal effect of EDTA. Filaments disappeared and cell volume increased when the organisms were transferred from hypertonic to hypotonic solutions; the shape changes were reversible.