Adaptations in growth factor requirements for lactic acid bacteria.

Adaptive processes in bacteria, whereby growth of organisms in deficient or drug-enriched media can be initiated through the production of new or latent enzyme systems, have been widely described. Reviews on this subject by Karstrom (1938), Dubos (1940), and Monod (1947) have provided examples of adaptation in bacterial carbohydrases and proteases, in enzymes of fermentation and glycolysis, and in detoxication systems. Although Sevag (1946) and others have questioned whether these processes involve true adaptation or the selective growth of variants already present in the culture, it is evident that adjustments to deficient media, either by individual cells or through quantitative changes in large populations, are commonplace occurrences. Adaptation with respect to vitamins and other accessory growth factors has been less frequently observed, particularly among the lactic acid bacteria. Notable exceptions are the loss of requirement for p-aminobenzoic acid by Lactobacillus arabinosus 17-5 (Lewis, through Pennington, 1946), for thiamine by Lactobacillus fermenti 9338 (Cheldelin, Bennett, and Kornberg, 1946), and for vitamin B12 and the tomato juice (TJ) factor (vitamin B6 phosphates) for Lactobacillus lactis Dorner (Shorb and Briggs, 1948). In the present study, adaptations have been observed in the requirements for several accessory growth factors by Lactobacillus gayoni and Leuconostoc mesenteroide8.