Thiamine Determination Comparative Study of Yeast-Growth, Yeast-Fermentation, and Thiochrome Methods

Eppright, Margaret A.; Williams, Roger J.

doi:10.1021/i560133a012

Cited by 6 publications

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“…The thiamine values referred to in the foregoing discussion are those obtained with Streptococcus salivarius as the test organism, because the yeast method has been shown not to be completely specific for thiamine (14). Although values obtained in this study by the yeast growth method were consistently higher (2 to 4 times) than corresponding values from the S. salivarius test (Table III), two sets of ratios obtained by dividing the thiamine content of each derived yeast by that of the control yeast agreed within 10 per cent, respectively, for seven of the yeast crops produced in the presence of inhibitors.…”

Section: Discussionmentioning

confidence: 99%

Effects of Certain Limiting Conditions on the Synthesis of B Vitamins by Yeast

Eppright¹,

Williams²

1946

Journal of General Physiology

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In yeast crops which were grown in the presence of various inhibitors, there was considerable variation in content of the various B vitamins. A higher degree of parallelism in variation in content was found to exist between thiamine and niacin than between any other pair of vitamins; this has been interpreted as indicating that the predominant functions of these two vitamins are their established rôles in fermentation. Values for inositol indicate that it may be involved in fermentation processes, but this is not the case for other members of the B complex. Biotin appears to be unique since in no case did the biotin content of yeast grown in the presence of an inhibitor fall below that of the control yeast. There was some evidence of synthesis of biotin, or a material with biotin activity, in the presence of certain inhibitors, the most striking instance being with sulfaguanidine. An exogenous supply of biotin was essential for extensive proliferation of F. B. yeast, and yeast grown in a medium to which biotin was the only added vitamin contained the B vitamins in amounts very similar to those found in the control yeast, the most marked differences being in increased vitamin B6 and p-aminobenzoic acid contents. In the absence of biotin, significant amounts of all of the B vitamins except biotin were synthesized, both in the presence and absence of certain other members of the B complex. The addition of thiamine, pyridoxine, inositol, and ß-alanine to the culture medium caused a reduction in the amounts of vitamin B6 and p-aminobenzoic acid synthesized. F. B. yeast was able to grow in a xylose medium only when certain of the B vitamins were present, and even then growth was limited. Evidence was obtained for some synthesis of all of the vitamins investigated except biotin and vitamin B6. The most significant differences in vitamin content between galac yeast and the parent F. B. strain were in folic acid and vitamin B6, the former being considerably reduced in amount, the latter being increased.

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Section: Discussionmentioning

confidence: 99%