Some Interrelationships of Pyridoxine, Alanine and Glycine in Their Effect on Certain Lactic Acid Bacteria

Abstract

Various investigators1 2, 3 have shown that pyridoxine (vitamin B6) under certain conditions is a necessary growth factor for certain species of lactic acid bacteria. One such organism is Streptococcus lactis R. In a detailed study of the requirement of this organism for pyridoxine, Snell, et al.,4 showed that there existed in natural products a substance which could be derived from pyridoxine by metabolic processes, which far surpasses pyridoxine in its physiological activity for this organism. To distinguish this substance from synthetic pyridoxine it was tentatively called "pseudopyridoxine." It was later shown5 that if heat sterilization were avoided, pyridoxine was almost without growth-promoting activity for this organism. It became highly active on autoclaving with the basal culture medium. The degree of activity increased as the period of heating was increased. The effect was traced to interaction during autoclaving between pyridoxine and the amino acids of the medium; presumably "pseudopyridoxine" or a substance of similarly high activity for the test organism was formed in small amounts.While investigating the effect of individual amino acids in promoting the above "activation" of pyridoxine during heating, it was found that large amounts of alanine completely replaced pyridoxine as a growth factor for this organism. Glycine, on the other hand, inhibited growth. This inhibitory effect of glycine was removed, within limits, by additional amounts of pyridoxine, but not by additional amounts of any of the other vitamins. It was similarly removed-even more effectively-by alanine, 66 PROC. N. A. S.

Correlation of the Vitamin Requirements with Cultural and Biochemical Characters of Lactobacillus spp.

“…There is the example described by Ford et al (1958) in which Streptococcus bovis exhibited a number of nutritional requirements when cultivated aerobically, although anaerobically the organism grew well in the absence of any added vitamin. The interrelation between pyridoxine and alanine was noted by Snell & Guirard (1943), and Griffin & Racker (1955) showed that the CO, requirement of Neisseria gonorrhoeae could be replaced by hypoxanthine, uracil and oxalacetate. These are only a few of the examples which can be cited; they serve to emphasize the caution which must be exercised.…”

Two Glycine Riboswitches Activate the Glycine Cleavage System Essential for Glycine Detoxification in Streptomyces griseus

“…he inhibition of bacterial growth by glycine is well established (1)(2)(3), and the cell wall is the main target of glycine action (4). Glycine is incorporated instead of alanine into peptidoglycan precursors (5,6), and eventually into peptidoglycan (4).…”

“…In addition, because glycine-containing peptide units are poor substrates in the transpeptidation reaction, a high percentage of muropeptides are not cross-linked, resulting in severely restricted growth (4). Sensitivity to an excess of glycine has been observed in various bacteria, including Bacillus subtilis, Streptococcus lactis, and Staphylococcus aureus (1,3). However, glycine is the simplest material for protein synthesis, despite its toxic activity.…”

Growth Factors and Growth Inhibitors for Micro-organisms

“…coli by cultivation in the presence of methionine and sulphanilamide supports their conception of the interrelation of methionine and p-aminobenzoic acid in metabolism (Kohn and Harris, 1942). Snell and Guirard (1943) found that alanine in sufficient concentration could completely replace pyridoxin for the growth of Streptococcus lactie; no other amino-acid did this. In the conditions of tho test, glycine and threonine and, at higher concentrations, serinc and p-alanine inhibited growth.…”

“…This inhibition was abolished by pyridoxin but by no other vitamin, and by alanine. Examples of inhibitions by certain amino-acids and their antagonization by other amino-acids, at very low concentrations, were first carefully studied by Gladstone (1939) but, in the case studied by Snell and Guirard (1943), there is the furthcr relation with pyridoxin metabolism. Thus both the examples mentioned here are cases where, presumably, metabolic reactions involving the essential metabolites, p-aminobenzoic acid and pyridoxin, are linked with reactions involving amino-acids.…”