The effect of 0 2 and COs on proteiriase biosynthesis by nonproliferating cells of Streptococc~is faecalis var. liquefacisrts in chenlically defined media were studied. I n the absence of COs,.Or (1% in N?) s t i~n~~l a t e d proteinase formatioil by promoting earlier synthesis and by increasing the rate of enzyme biosynthesis. Carbon dioxide ~~n d e r anaerobic conditions only enhariced the rate of protciilase synthesis. The sti~u~ilatory effect of the two gases was not additive. Glucose SLIPported a greater yield of proteinase than galactose under all conclitions of 0 2 and COL availability. Galactose \vns stinl~~latory in the presence of glucose only ~inder aerobic conditions (1% 0 2 in N?) when atinosphcric CO? \vas removed. Oxygen a t the 20% level inhibitetl proteinase formation by increasing the rate of arginine disappearance from the medi~im.
IntroductionNutritional aspects of proteinase biosynthesis by nonproliferatiilg cells of Streptococciis faecalis var. liq~iefaciens in static culture under a n atmosphere of air were first described bli Rabin and Zimmerman (18) and IIartman et al. (9). The former authors established the amino acid and carbohydrate requirements and the latter established the vitamin and nitrogen base requirements. Hartman and Zimmerman (8) studied the inordinately large arginine requirement demonstrated by Rabin and Zimmerman (18) and found that, under the microaerobic conditions, the arginine dihydrolase enzyme system (10) limited proteinase biosynthesis as a result of the very rapid degradation of arginine. During this ~nvestigation, it was observed that aeration, as provided by the incubation of the cells in a shaken Warburg vessel with an atmosphere of air, inhibited proteinase forn~ation but did not inhibit the activity of preformed enzyme.The present investigation was undertalcell to define more fully the effects of oxygen and carbon dioxide on proteinase biosynthesis by ilonproliferating cells of S . faecalis var. liquejaciens in chemically defined media.
Materials and MethodsThe organism used in this study was Streptococcnis jaecalis var. liquefaciens, strain 31, which was originally obtained from the Division of Bacteriology, Cornell University. Stoclc cultures were maintained a t -17 OC in litmus milk. Incubation temperature for all experiments was 37 OC. The basic medium was the optimal adaptation ~n e d i u~n (final >IS3/1 medium of Hartman et al.
( 9 ) ) .'This material was talccn from a thesis submitted by James F. Swiencicki in partial fulfillment of the requirements for a M.Sc. degree a t St. Bonaventure University.