The occurrence in soil of a large group of bacteria which require vitamin B12 has been reported by Lochhead and Thexton (1952). Thirty cultures obtained from 534 isolates showed dependence upon vitamin B12 for growth. Lochhead and Burton (1954) grouped these 30 cultures into 10 types, based on morphological and physiological characteristics. A study of the nature of the vitamin B12 requirements...

The overwhelming consensus in the mainstream nutrition community, as well as among vegan health professionals, is that plant foods do not provide vitamin B12. Despite this, some vegan advocates still believe that plant foods provide all the nutrients necessary for optimal health and, therefore, do not address vitamin B12 when promoting the vegan diet. Other vegan advocates acknowledge the need ...

Several studies suggest that the vitamin B12 (B12) transport system can be used for the cellular delivery of B12-conjugated drugs, also in long-term treatment Whether this strategy will affect the endogenous metabolism of B12 is not known. To study the effect of treatment with excess B12 or an inert derivative, we established a mouse model using implanted osmotic minipumps to deliver saline, co...

Subacute combined degeneration ( SCD) due to vitamin B12 deficiency is common in North of Europe but sometimes it is seen in Iran. It can develop before the symptoms of anemia is obvious, with myelin injury and then axon and even neuron destruction in spinal cord, brain, optic and peripheral nerves. In this study two cases are reported; in the first patient, this disease in manifested by vitami...

I N PREVIOUS REPORTS’3 it was shown that uncoated charcoal adsorbs both free vitamin B12 and B12 bound to proteins, but charcoal precoated by mixing with saturating quantities of albumin adsorbs only free B12. This finding has been confirmed.4 The charcoal particles may be considered as solid microsponges and the albumin coat as a molecular sieve surrounding each sponge. Small molecules such as...

The human antibody immunoglobulin G1 (IgG1) b12 neutralizes a broad range of human immunodeficiency virus-type 1 (HIV-1) isolates in vitro and is able to protect against viral challenge in animal models. Neutralization of free virus, which is an antiviral activity of antibody that generally does not require the antibody Fc fragment, likely plays an important role in the protection observed. The...

Corrinoid (vitamin B12-like) cofactors contain various alpha-axial ligands, including 5,6-dimethylbenzimidazole (DMB) or adenine. The bacterium Salmonella enterica produces the corrin ring only under anaerobic conditions, but it can form "complete" corrinoids aerobically by importing an "incomplete" corrinoid, such as cobinamide (Cbi), and adding appropriate alpha- and beta-axial ligands. Under...

OBJECTIVE There is evidence that subclinical vitamin B12 (B12) deficiency is common in India. Vegetarianism is prevalent and therefore meat consumption is low. Our objective was to explore the contribution of B12-source foods and maternal B12 status during pregnancy to plasma B12 concentrations. DESIGN Maternal plasma B12 concentrations were measured during pregnancy. Children's dietary intak...

The cysG gene of Salmonella typhimurium is involved in synthesis of both cobalamin (B12) and siroheme (a cofactor required for SO3(2-) and NO2(2-) reductases). The failure to reduce SO3(2-) leads to cysteine auxotrophy, for which the enzyme is named. Although Escherichia coli does not synthesize B12 de novo, it possesses a very similar CysG enzyme which has been shown to catalyze two methylatio...