The biochemical molecules and processes on which life depends are exquisitely sensitive to the acid-base state, or pH, of their fluid environment. Mammals are known to regulate this fluid environment with great precision near pH 7.4. Although they have not been directly measured, the PIs assume that small mammals (less than 50 grams) regulate their acid-base state like larger mammals. However, Dr. Szewczak's laboratory has developed microsurgical and small blood volume techniques that have enabled acid-base measurement in small mammals, and their efforts indicate that small mammals regulate their pH at 7.3 and less. The PIs plan to investigate the acid-base state in a variety of mammals as small as seven grams to explore whether this is a general regulatory strategy of mammals at this scale.
Although this may seem like a small change in pH, it is sufficient to significantly alter biochemical processes. Because the earliest known mammals from the Triassic Period weighed 20-30 grams, this may provide essential clues for understanding mammalian organism and macromolecular evolution. This also has broad implications to many biological investigations because small mammals are so often the source for living materials used in laboratory preparations for tissue culture and biochemical investigations. Such preparations are adjusted to an assumed pH of 7.4, which could significantly alter function from a correct pH of 7.3 or less. Thus many standard laboratory protocols may require adjustment, and the results of many prior studies may require reconsideration.
