Acetoin metabolism in animal tissues

The acetoin-synthesizing activity has been studied in the skeletal muscles, brain, liver and spleen homogenates (numbered as the activity decreases). The acetoin-synthesizing activity drastically increases in case of the acetaldehyde excess and alcohol intoxication. The acetaldehyde concentrations of above 1.10(-3) M inhibit the liver pyruvate dehydrogenase activity and increase the non-oxidative transformation of pyruvate. Acetoin is rapidly metabolized in the organism eliminating from blood 10 minutes after its injection. Acetoin is an effective precursor in the biosynthesis of lipids.     

The formation of ornithine from proline in animal tissues

1. Homogenates of liver or kidney from rat, mouse, dog and guinea pig formed ornithine from proline but not from glutamate. Rat kidney was most active in this reaction and was used for further studies. 2. The overall reaction was found to be catalysed by proline oxidase to yield glutamic gamma-semialdehyde, followed by transamination of this product with glutamate as catalysed by ornithine-keto acid aminotransferase. 3. The unfavourable equilibrium of the ornithine-keto acid aminotransferase reaction was overcome chiefly by glutamate dehydrogenase in the tissue, which removed the alpha-oxoglutarate produced, by reduction with endogenous ammonia and NADH. 4. Aspartate aminotransferase in these preparations also aided in the removal of alpha-oxoglutarate. In this case the overall reaction was driven also by the rapid decarboxylation of oxaloacetate. 5. No evidence could be found for a pathway of ornithine synthesis involving acylated intermediates as has been observed in some micro-organisms. 6. The rate of ornithine synthesis in homogenates of several rat tissues paralleled the activity of ornithine-keto acid aminotransferase in these tissues, indicating that this enzyme was rate-determining for the synthesis. 7. The possible influence of these reactions on urea synthesis is discussed.     

Granule formation in animal tissues byCandida albicans

Summary 1. Granule formation byCandida albicans in the internal organs of experimental animals is described. This appears to be the first time such an observation has been made.2. Ring formation by fungi under different conditions is cited, and although different explanations have been proposed by different authors, the supposition is made that a common growth pattern is involved.Supported in part by a grant from the Eli Lilly Company and partly by an institutional grant from the American Cancer Society.