The microbiological assay of vitamin B12 with Lactobacillus leichmannii.
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چکیده
منابع مشابه
Microbiological assay for vitamin B12 performed in 96-well microtitre plates.
A simplified microbiological assay for vitamin B12 estimation, completed on microtitre plates using a colistin sulphate resistant strain of Lactobacillus leichmannii (NCIB 12519), and cryopreserved cultures is described. The new assay correlated well with a more conventional "tube" assay and was not influenced by the presence of antibiotics in serum. Evaluation of assay performance showed excel...
متن کاملExtraction of serum vitamin B12 for radio-isotopic and Lactobacillus leichmannii assay.
The protein precipitates discarded during the extraction process of the Lactobacillus leichmannii vitamin B12 assay have been shown to contain significant amounts of vitamin B12. This loss of vitamin B12 provide a satisfactory explanation for many of the descrepancies between the serum vitamin B12 values obtained by the L. leichmannii method and the radio-isotopic method of Raven et al (1969). ...
متن کاملA 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...
متن کاملLiquid Nitrogen Freezing in Microbiological Assay Systems. I. Preservation of Lactobacillus Leichmannii for Direct Use in the Vitamin B12 Assay.
Suspensions of Lactobacillus leichmannii were stored in liquid nitrogen and were used as direct inocula in vitamin B(12) assays. Complete recovery of viable cells was obtained when the suspensions in basal B(12) medium were rapidly frozen by direct immersion into liquid nitrogen and rapidly thawed by agitating the suspensions in a water bath at 40 C. Greater than 90% destruction occurred when t...
متن کاملThe use of potassium cyanide in the lactobacillus leichmannii assay for vitamin B12.
Studies by several investigators (Stokstad, Dornbush, Franklin, Hoffmann, Hutchings, and Jukes, 1949; Skeggs, Nepple, Valentik, Huff, and Wright, 1950) have indicated that an increased growth response was obtained to liver concentrates with thioglycolic or thiomalic acids when vitamin B12 activity was determined with Lactobacillus leichmannii. This was attributed to the prevention, by such redu...
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 181 2 شماره
صفحات -
تاریخ انتشار 1949