Observations on the etiologic relationship of achylia gastrica to pernicious anemia. XIII. Hematopoietic activity of vitamin B12a (Vitamin B12b).

Numerous reports have appeared on the nutritional requirements of Bacillus coagulans, but considerable confusion still exists concerning the folic acid (pteroylglutamic acid) requirement of members of this group. Several workers state that folic acid is not required by B. coagulans (Andersen and Werkman, 1940; Cleverdon et al., 1949; Knight and Proom, 1950; Allen, 1953; Proom and Knight, 1955). In contrast, Campbell and Williams (1953) reported that 4 strains of B. coagulans required folic acid when grown in a chemically defined medium at either 45 or 55 C and 3 of the 4 strains required folic acid at 36 C. Baker et al. (1955) demonstrated that a single strain of B. coagulans required folic acid at 55 C recommended its use for the microbiological assay of this vitamin. Touba (1956) and Ordal (1957) reported that B. coagulans strain 43P required folic acid for spore formation. O'Brien and Campbell (1957) showed that this strain also required folic acid for spore outgrowth and vegetative cell development. While the present investigation was in progress, Humphreys and Costilow (1957) reported that folic acid stimulated the growth of 22 strains of B. coagulans in a semi-defined medium and was required by 19 strains for growth in a defined medium. The experimental conditions employed in the above reports have been quite varied, particularly with respect to the use of different strains, different methods of preparing inocula, different test media, and different incubation times and temperatures. The present investigation was initiated to determine the folic acid requirement of 20 strains of B. coagulans, including strains

Folic acid requirement of Bacillus coagulans.

Pernicious anemia in Asiatic Indians.

Summary


Prof. Sir John Dacie was one of the most distinguished haematologists of the 20th century. He died on 12 February 2005 at the age of 92. This annotation is intended to give an impression of his career, and his role in the development of haematology in the UK and beyond. It describes his approach to haematological practise, taking account of both clinical and laboratory aspects, and reviews his published works over a range of haematological topics.

Sir John Dacie MD, FRS, FRCP, FRCPath.

The structure of vitamin B12, as we think of it today, is based on a fascinating complex of evidence obtained by X-ray analysis and by more traditional chemical means. We have reached a position in which we can almost say we “see” the molecule if not quite as clearly, perhaps, as we should like. We can assign positions in space to the atoms of this very large molecule within less than half an Angstrom unit in two different crystal structures. We know its absolute configuration and the exact stereochemistry of all the different asymmetric centres present. Yet most of this knowledge rests on a way of using X-ray diffraction effects which is very far from rigid in its application. Part, at least, of our evidence that our method works at all is the character of the structure it has given us for B12 a structure that fits in an extraordinarily reasonable way with such a variety of observations, chemical and stereochemical and biogenetic, that it is impossible not to believe it is essentially correct.

X-ray Analysis and the Structure of Vitamin B12

Isolation and chemistry of vitamin B12.

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Isolation and chemistry of vitamin B12.

Isolation and chemistry of vitamin B12.