Thymine in the acid-soluble fraction of Arbacia eggs

Mature Arbacia eggs were extracted with cold dilute perchloric acid, the extract concentrated, and the concentrate digested in hot perchloric acid. Thymine was recovered from the digest by paper chromatography, and the amount per egg found to be about 5 times the amount per sperm. This was the amount expected from previous experiments and is believed to represent all or almost all of the thymine in the egg. The result supports previous observations that DNA is absent from the mature egg although present in the nucleus of the egg in the germinal vesicle stage. No thymine could be recovered from a similar extract of 5,000 times as many sperm of the same species. The observations are consistent with the theory that DNA and its derivatives act as metabolic antagonists of the corresponding ribose compounds.     

Fractionation of the nucleotides of the acid-soluble liver fraction of rats

A method for separation of rat liver acid-soluble nucleotides was developed including ion exchange polyethyleneimine cellulose chromatography, followed by rechromatography of the separate fractions on Dowex 1 and Aminex MS resins. It is simple, reproducible and does not require expensive reagents and devices. The sensitivity of the method in respect to orotate is 100 pM in a sample. Data on the content of liver basic 5'-ribonucleotides and their derivatives were obtained by the proposed method.     

Polymorphism in a casein fraction of sows' milk

Polyacrylamide vertical gel electrophoresis was used to separate the caseins of sows' milk. Polymorphism was found in a region of the gels designated Cn₃. The Cn₃ polymorphism consists of two bands which appear to be controlled by two codominant alleles designated Cn ₃ ^A and Cn ₃ ^B . Homozygotes possess one band and heterozygotes posses both bands of equal intensity giving the following phenotypes: Cn₃A, Cn₃AB, and Cn₃B. A chi-square test for goodness of fit of the observed phenotypes to that expected by the Hardy-Weinberg equilibrium formula and a segregation analysis of eight matings involving 19 female progeny conform to the hypothesis that the Cn₃ polymorphism is controlled by two codominant autosomal alleles. Further family studies will be necessary to confirm the genetic control of the Cn₃ polymorphism.Deceased.     

The relationship of acid-soluble glycogen to yeast flocculation.

A relationship between yeast flocculation and intracellular acid-soluble glycogen has been established which has been substantiated using flocculation mutants (mutants with altered capacities to flocculate) as well as a normal strain of Saccharomyces carlsbergensis. Sound evidence exists to implicate physiological differences in carbohydrate metabolism (glycogen storage) to this physical property of brewing significance.     

Production of microbial rennin

Fungal strains were compared for their ability to produce milk-coagulating enzyme with low non-specific proteinase activity.Rhizomucor miehei VTT-D-82193 (ATCC 16457) was chosen as the best source of microbial rennin. The enzyme produced compared favourably with two commercial coagulant preparations of microbial origin. The work provides a basis for comparison with other production processes for microbial rennin, including recombinant chymosin.     

Increased fraction of acid-soluble proteins in 0.35 M NaCl extracts of nuclei from rat liver tumors

1. The fraction of proteins extracted from nuclei with 0.35 M NaCl and soluble in 2% trichloroacetic acid was examined in five Morris hepatomas and rat liver. 2. This fraction was a much greater percentage of the total 0.35 M NaCl soluble proteins in the tumors than in normal or regenerating liver. 3. In part, this difference was due to proteins with molecular weights greater than high mobility group proteins. 4. The conditions for precipitation of high mobility group proteins 1 and 2 with trichloroacetic acid were found to differ in hepatoma and liver fractions.     

Different sensitivity of human red cell casein kinases towards glycoaminoglycans

Heparin specifically inhibits cytosolic casein kinase from human erythrocyte and has no effect on membrane casein kinase. Other glycoaminoglycans have little or no effect on cytosolic casein kinase activity. Study of inhibition mechanism reveals that heparin acts as a non competitive inhibitor with respect to both substrates: ATP and casein.     

Proteomic characterization of specific minor proteins in the human milk casein fraction

Human milk contains many bioactive proteins that are likely to support the early development of the newborn. The aim of this study was to identify whether there are specific minor proteins associated with the human milk casein micelle prepared by the acid precipitation method. Protein identification was performed by liquid chromatography tandem mass spectrometry analysis. Eighty-two proteins were identified in the casein micelle, 18 of which are not present in their whey compartment. Thirty-two of these proteins specifically associated with the casein micelle have not previously been identified in human milk or colostrum. Proteins involved in immune function comprised the major part (28%) of total proteins, and another significant part is involved in metabolism/energy production (22%). Most of the proteins were of extracellular or cytoplasmic origin (accounting for 50 and 29%, respectively). This study indicates that various soluble proteins should be considered as part of the casein compartment, prepared by the acid precipitation method. The data provide new insight not only into the proteomic profile of the human milk casein micelle and its physiological significance, but also into the proper proportion of casein and casein-associated proteins to use in infant formula.