TY - JOUR TI - Molar Growth Yields of Certain Lactic Acid Bacteria as Influenced by Autolysis AU - Hassan, H. Moustafa AU - Collins, E. B. T2 - Journal of Bacteriology AB - Molar growth yields determined from batch cultures of Streptococcus diacetilactis and S. faecalis were appreciably greater at the peaks of maximal growth than after continued incubation and considerable autolysis. The higher molar growth yields were about equal to those determined in a continuous culture. Autolysis during logarithmic growth was minimal. The average Y value for adenosine triphosphate (ATP), determined by using limiting concentrations of glucose, galactose, lactose, and maltose for growing S. diacetilactis and limiting concentrations of glucose for growing S. lactis, S. cremoris , and S. faecalis , was 17.0. This is close to the Y (arginine) value of 17.8 determined with S. faecalis , but 62% greater than the generally accepted value of 10.5. Data are presented indicating that the often-used Y (ATP) value of 10.5 is erroneously low. DA - 1968/7// PY - 1968/7// DO - 10.1128/jb.96.1.117-125.1968 VL - 96 IS - 1 SP - 117–125 SN - 0021-9193 1098-5530 UR - http://dx.doi.org/10.1128/jb.96.1.117-125.1968 ER - TY - JOUR TI - Role of Galactose or Glucose-1-Phosphate in Preventing the Lysis of Streptococcus diacetilactis AU - Hassan, H. Moustafa AU - Collins, E. B. T2 - Journal of Bacteriology AB - Cells of Streptococcus diacetilactis DRCI grown at 32 C in media containing glucose as the energy source were osmotically fragile and began to lyse immediately after growth was stopped (by the action of chloramphenicol or the exhaustion of glucose), unless they were then stabilized by hypertonic medium or spermine or by storage at low p H or low temperature, or both. In media containing excess glucose, with growth limited by exhaustion of some nutrient other than the energy source, the appearance of lysis was masked by the occurrence of a balance between lysis and synthesis. The osmotic fragility apparently resulted from inability of the organism to use glucose as an adequate precursor of galactosamine, and conditions of temperature and p H that promoted rapid growth on glucose were particularly conducive to the formation of cells that lysed readily. Growing the organism in media containing galactose, lactose, maltose, or glucose (at 17 C) as energy source resulted in the formation of cells that were resistant to lysis and richer in galactosamine than unstable cells formed on glucose at 32 C. The results indicate that the organism phosphorolyzes maltose to glucose plus β-glucose-1-phosphate, and suggest that it can use the β-glucose-1-phosphate in place of α-glucose-1-phosphate in the formation of cell materials. DA - 1968/2// PY - 1968/2// DO - 10.1128/jb.95.2.592-602.1968 VL - 95 IS - 2 SP - 592–602 SN - 0021-9193 1098-5530 UR - http://dx.doi.org/10.1128/jb.95.2.592-602.1968 ER -