Helen R. Skeggs

Orotic Acid and Related Compounds in the Nutrition of Lactobacillus bulgaricus 09

Summary The orotic acid requirement of Lactobacillus bulgaricus 09 can be met by ureidosuccinic acid (10-20% as active as orotic acid) or by 5-(carboxy-methylidine)-hydantoin (30-40% as active as orotic acid but not by any one of a large group of lated or unrelated compounds studied. The data are taken as microbiological evidence that ureidosuccinic acid and possibly ureidofumaric acid (derived from 5-(carboxy-methylidine)-hydantoin) are precursors of the pyrimidine ring. Data on the distribution of orotic acid in nature are presented.

Vitamin B complex studies with diets differing in the level of protein.

Summary Experiments involving the feeding to rats of diets varying in the level of casein were carried out. The following facts were established: 1. In ad libitum feeding the fecal elimination of the B vitamins studied closely paralleled the level of dietary protein. In equalized feeding the fecal elimination of biotin, pantothenic acid, and nicotinic acid was directly proportional to the protein content of the diet. 2. The hepatic storage of the B vitamins studied was correlated directly with the protein content of the diet. This relationship existed both in ad libitum and controlled feeding experiments, The hepatic stores of folic acid, biotin, pantothenic acid, and riboflavin found in rats fed the lower levels of protein were indicative of either frank or incipient deficiencies. 3. Leucopenia and agranulocytosis were induced readily by diets low in protein. Under these conditions the existence of the dyscrasia was correlated with the reduced fecal elimination and hepatic storage of folic acid. When diets more nearly optimal with respect to casein level, but in greatly restricted amounts, were fed, leucopenia and agranulocytosis were encountered despite the existence in many of the animals of adequate stores of folic acid. Reasons were presented for attributing the condition to the ingestion of insufficient protein and, more specifically, of certain essential amino acids. 4. Low hematocrits, hemoglobin values, and red cell counts were observed occasionally in rats ingesting low protein diets or highly purified diets containing succinyl-sulfathiazole (SST).

Affinity of avidin for biocytin.

Summary Avidin has a greater affinity for biotin than for biocytin. The affinity ratio for biocytin, as previously defined, is about 4.

A Growth-Promoting Substance for L. bulgaricus 09 in Whey Isolation and Identification as Orotic Acid

Summary Various natural substances especially whey were found to contain a substance required for growth of Lactobacillus bulgaricus 09. In the survey of known compounds orotic acid was found to satisfy the requirement of this organism for natural material. The microbiologically active material was isolated from one of the natural sources, whey, and identified with orotic acid.SummaryVarious natural substances especially whey were found to contain a substance required for growth of Lactobacillus bulgaricus 09. In the survey of known compounds orotic acid was found to satisfy the requirement of this organism for natural material. The microbiologically active material was isolated from one of the natural sources, whey, and identified with orotic acid.

Affinity of avidin for certain analogs of biotin.

Summary The avidin combinability of a number of compounds having some structural similarity to biotin was investigated. The specificity of the avidin reaction was emphasized by the finding that of the 19 compounds studied avidin possessed significant affinity only for δ- (2,3-ureylene-cyclohexyl-) valeric acid (XVII), γ- (3,4-ureylene-cyclohexyl)-butyric acid (XVIII) and δ-(3,4-ureylene-cyclohexyl )-valeric acid (XIX). The relative affinity ratio for Compound XVII was found to be about 14. Compounds XVIII and XIX, although definitely capable of combining with avidin, had affinity ratios too high for practical measurement.

Influence of Certain Purines, Pyrimidines, and Pterins on Synthesis of “Folic Acid” by Aerobacter aerogenes.

Summary When xanthopterin was added to cultures of A. aerogenes only small amounts of “folic acid” were synthesized by the organ-ism. Xanthopterin was without effect on the resulting turbidity of the cultures or on the amount of biotin produced. Several other purines, pyrimidines, and pterins were without effect on the growth of the organism or on the production of “folic acid” or of biotin. It is suggested that xanthopterin either may partially replace “folic acid” in metabolism or its structural similarity to an hypothetical intermediate in the microbiological synthesis of “folic acid” enables it to inhibit the synthesis or utilization of the intermediate.

Biocytin in Bacterial Deamination of Aspartic Acid

Summary Biocytin, like biotin, has been shown to be active in stimulating the aspartic acid deaminase system of bacterial cells that have been inactivated by exposure to pH 4 M phosphate buffer.

Biotin in the bacterial deamination of certain amino acids.

Summary Inactivation of bacterial aspartic acid deaminase activity by exposure of cells to pH 4 M phosphate buffer and its reactivation with biotin has been confirmed.