Biomaterial Database

A radiometric microbiologic method for vitamin B12 assay. 1977

M F Chen, and P A McIntyre, and H N Wagner

A radiometric microbiologic method was developed for assaying vitamin B12 in human serum. In the presence of 14C-arginine and cyanocobalamin, Lactobacillus leichmannii produced significant amounts of 14CO2 within 16-20 hr. The amount of 14CO2 evolved was optimized with the use of guanido-labeled arginine and is proportional to the amount of cyanoco-balamin added. The method gave satisfactory recovery of added vitamin B12 to sera, and it gave values comparable to the standard microbiologic (turbidimetric) method using L. leichmannii. The radiometric microbiologic method allowed elimination of several steps considered essential in the standard microbiologic methods: (A) Extraction of vitamin B12 bound to serum proteins could be accomplished in one autoclaving step with the assay medium at 15 psi for 3-5 min; (B) The precipitated serum proteins did not need to be separated, since they do not interfere with this assay,

UI	MeSH Term	Description	Entries
D007778	Lactobacillus	A genus of gram-positive, microaerophilic, rod-shaped bacteria occurring widely in nature. Its species are also part of the many normal flora of the mouth, intestinal tract, and vagina of many mammals, including humans. Lactobacillus species are homofermentative and ferment a broad spectrum of carbohydrates often host-adapted but do not ferment PENTOSES. Most members were previously assigned to the Lactobacillus delbrueckii group. Pathogenicity from this genus is rare.
D008722	Methods	A series of steps taken in order to conduct research.	Techniques,Methodological Studies,Methodological Study,Procedures,Studies, Methodological,Study, Methodological,Method,Procedure,Technique
D002250	Carbon Radioisotopes	Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.	Radioisotopes, Carbon
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001120	Arginine	An essential amino acid that is physiologically active in the L-form.	Arginine Hydrochloride,Arginine, L-Isomer,DL-Arginine Acetate, Monohydrate,L-Arginine,Arginine, L Isomer,DL Arginine Acetate, Monohydrate,Hydrochloride, Arginine,L Arginine,L-Isomer Arginine,Monohydrate DL-Arginine Acetate
D014805	Vitamin B 12	A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.	Cobalamin,Cyanocobalamin,Cobalamins,Eritron,Vitamin B12,B 12, Vitamin,B12, Vitamin