Abstract
Two recent publications by Drs. Bachman 1 and Williams 2 dealing with the vitamine requirements of yeasts suggest that the methods developed are adaptable to quantitative measurement of vitamine content (B variety). At the suggestion of the senior author Miss Stevenson has conducted experiments with both methods and in this report are presented some of the results with the Bachman test.
Briefly this method consists in planting yeast cells in a culture medium (Nageli's solution: 100 c.c. distilled water; 10 gms. dextrose; 1 gm. ammonium nitrate; 0.05 gms. calcium phosphate; 0.5 gms. potassium acid phosphate; 0.25 gms. magnesium sulfate) contained in a Durham or Smith fermentation tube and incubating the tubes at 28-32° C. to obtain gas formation. To these tubes are added vitamine “B” extracts from various sources and Dr. Bachman's results showed that in the absence of such extracts gas formation either fails to take place or at least very slowly.
Our experiments aimed to confirm Dr. Bachman's results, to determine whether the method gave promise of use quantitatively and whether it might be used to detect the “B” vitamine qualitatively. The results of our experiments follow:
The results of the various experiments are obvious from the records. It need merely be pointed out that in none of the duplicates were we able to repeat the gas figures exactly and that for quantitative measurement the test needs further standardization to be efficient in comparing solutions. The great variability of the yeast loopfuls obtained in this method would easily give rise to considerable variation and experiments are being made along this line to be reported later.
As a means of studying presence of “B” Vitamine in large or small quantity and as an index more reliable than rat feeding experiments the test offers such marked advantages in sensitiveness and in speed of observation that it seems well worth while to devote more time to its improvement.
Get full access to this article
View all access options for this article.