Metabolism of Pyrimidine Nucleotides in a Microorganism

Metabolism of cobalamins by a soil microorganism.

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...

Pyrimidine metabolism in man.

Metabolism of alloxanic acid in a soil microorganism.

Alloxan is a polyoxy-pyrimidine of unusual biological interest, being the agent of choice for producing experimental diabetes (Shaw-Dunn, Sheehan, and McLetchie, 1943). Despite the fact that it has been used extensively for many years, very little is known of its ultimate fate in mammals or other forms of life. It is exceedingly unstable at physiological pH values and is spontaneously converted...

Pyridine nucleotides in erythrocyte metabolism.

Pyrimidine metabolism in Tritrichomonas foetus.

The anaerobic parasitic protozoa Tritrichomonas foetus is found incapable of de novo pyrimidine biosynthesis by its failure to incorporate bicarbonate, aspartate, or orotate into pyrimidine nucleotides or nucleic acids. Uracil phosphoribosyltransferase in the cytoplasm provides the major pyrimidine salvage for the parasite. Exogenous uridine and cytidine are mostly converted to uracil by uridin...