A METHOD FOR THE MICROBIOLOGICAL ASSAY OF VITAMIN B12

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 B12 with Lactobacillus leichmannii.

An automated microbiological method for the measurement of vitamin B12.

An automated method for the microbiological assay of vitamin B(12) is described. A chloramphenicol-resistant strain of Lactobacillus leichmannii is used as the test organism and this eliminates the need for sterilization or aseptic addition. Precipitation of the serum protein is avoided by dilution of the serum with a glutamic/malic acid solution before heating the preparation to free the vitam...

Microbiological assay for vitamin B12 with use of a colistin-sulfate-resistant organism.

In this simplified microbiological assay for serum vitamin B12, Lactobacillus leichmanii (NCIB 8117) adapted to tolerate high concentrations (500 mg/L) of the polymyxin antibiotic colistin sulfate is used. Results were similar in parallel experiments in which we used both the parent strain of L. leichmanii (NCIB 8117), and the new adapted strain. Evaluation of assay performance showed excellent...

Microbiological assay of vitamin B12 with a mutant strain of Escherichia coli.

Two strains of Lactobacillus leichmanii, ATCC 7830 and ATCC 4797, are generally used for vitamin B12 assay. However, the complex growth requirements and the lack of specificity to vitamin B12 of these lactic acid bacteria make the determination of vitamin B12 difficult (Hoffmann et al., 1948; Skeggs et al., 1948; Snell et al., 1948; Capps et al., 1949; Kitay et al., 1949; Peeler et al., 1949; W...