THE GROWTH OF A TURBIDOSTAT YEAST CULTURE IN THE PRESENCE OF HIGH-CONCENTRATIONS OF VARIOUS COMPOUNDS IN A STEADY-STATE REGIME AND UNDER OSMOTIC SHOCK

The growth of a turbidostat culture of the yeast strain Saccharomyces cerevisiae 14 was studied under steady-state conditions in the presenc e of high (1.2-3 M) concentrations of various soluble compounds and un der transition conditions upon rapid concentration changes. The concen tration was varied from the optimal one to that decreasing the growth rate two times and back to the optimal one. The effects of the followi ng compounds on yeast growth in the steady-state regime were studied: glucose, sucrose, (NH4)(2)SO4, MgSO4, NaH2PO4, Na2SO4, KCl, NaCl, NH4C l, MgCl2, and LiCl. To study transition processes, the following compo unds were used: NH4Cl, NaH2PO4, MgCl2, MgSO4, (NH4)(2)SO4, KCl, and Na Cl. When the NaCl concentration increased rapidly, the transition proc ess was completed in the first generation. For the other compounds, th is process lasted for several generations. The transition process was completed in the first generation in cultures previously inhibited by (NH4)(2)SO4 or NaH2PO4. Cell volume varied insignificantly among-stead y-state cultures grown under different conditions, except for those in hibited by NH4Cl or MgSO4. The level of glucose utilization increased with an increase in the concentrations of the compounds studied. The r atio of the duration of the juvenile developmental phases (prophase, m etaphase) to the duration of the postjuvenile phases (anaphase, teloph ase) was constant over the concentration ranges tested. The inhibitory effect of a compound depended on its chemical nature rather than on i ts osmotic effect.