A Microbiological Assay of Vitamin B1.

Microbiological assay of vitamin B12 in the presence of tetracycline.

Treatment of a pharmaceutical preparation of vitamin B(12) and tetracycline with an ion-exchange resin by the batch method differentially adsorbed tetracycline, making possible a statistically reproducible microbiological assay of vitamin B(12) by the standard Escherichia coli plate method.

THE MICROBIOLOGICAL ASSAY OF VITAMIN Bu WITH LACTOBACILLUS LEICHMANNII

The microbiological assay of vitamin B12 with Lactobacillus leichmannii.

A Differential Microbiological Assay

Although vitamin B12 can be assayed biologically with mice, chicks or rats, the microbiological method of assay is preferred since it is more rapid and economical. One serious shortcoming of many microbiological B12 assay procedures is the lack of specificity when crude materials are assayed. Crude materials can contain inhibitory or stimulatory factors which cause serious errors in assay resul...

Vitamin B1

Vitamin B1 is a watersoluble vitamin. It consists out of a pyrimidineand a thiazol ring, which are synthesized independently and linked afterwards.Vitamin B1 is de novo produced by many plants and microorganisms. Humans and animals have to take it up by nutrition. They are only able to do the phosphorylation reaction of the thiamin molecule. Thiamin is found free and as mono-, diand triphosphat...