R. W. Wannemacher

Use of a single tissue extract to determine cellular protein and nucleic acid concentrations and rate of amino acid incorporation.

Abstract A method has been described for the determination of DNA, RNA, protein concentrations, and protein radioactivity in the same aliquot. This procedure permits an accurate and consistent separation and measurement of these three biochemical components of the cell. The precision for the determination of DNA has been increased by carefully controlling the conditions for hydrolysis of this compound. This procedure has great versatility and allows for accurate correlation of many variables.

Cell Population Changes in the Intestinal Epithelium of the Rat following Starvation and Protein-Depletion

Summary In rats starved for periods up to 10 days or fed a protein-free diet for periods up to 11 weeks, the number of cells per crypt of the small intestine declined steadily. During this time, however, with the exception of the rats kept on a protein-free diet for 11 weeks, the number of cells per crypt synthesizing DNA and dividing remained the same as in the control crypts, thus resulting in an increase in the labeling and mitotic indices in the experimental animals. The hypoplasia in the crypts, despite the fact that there were a constant number of cells per crypt undergoing proliferative activity was due to the inhibitory effect of the dietary regimes on the generation cycle time. The synthetic and the mitotic phases of the cycle are inhibited to the greatest extent.

The Effect of Leukocytic Endogenous Mediator (LEM) on Serum Copper and Ceruloplasmin Concentrations in the Rat

Summary Leukocytic endogenous mediator (LEM) was shown to produce significant increases in serum Cu and ceruloplasmin concentrations in the rat within 12 hr after its administration. This increase coincided with an increase in the incorporation of 3H-leucine into total serum proteins which also was shown to be induced by LEM.

Mediator of Hepatic Amino Acid Flux in Infected Rats

Summary Live D. pneumoniae, but not endotoxin or double-stranded polynucleotides, stimulated a flux of cycloleucine into liver. Sterile, 2-hr serum from D. pneumoniae-infected rats and secretions obtained from rat peritoneal leukocytes can also mediate a flux of cycloleucine into liver of normal recipient rats. The data were interpreted as evidence that one or more proteins synthesized and excreted by leukocytes can act as humoral intermediates in the stimulation of amino acid flux into liver tissue.

Further Characterization and Species Specificity of Leukocytic Endogenous Mediator (LEM)1

Summary A degree of cross species susceptibility was observed on the effects of leukocytic endogenous mediator (LEM) on serum zinc depression and amino acid flux. LEM was shown to be protein in nature, and relatively stable under a wider range of pH and conditions of storage. Although LEM shares several chemical and physical characteristics with endogenous pyrogen (EP), some differences between the chemical properties and species specificity of these two mediators were noted.

Incorporation of S35 from L-Methionine in Tumor-bearing and Protein-depleted Rats.

Summary The specific activities of total liver protein and of the proteins of mitochondria, microsomes, and cell sap were higher in the protein-depleted rats than in the controls. Specific activities of these proteins in tumor-bearing rats, on the other hand, decreased below those in control animals. As the specific activity of the liver proteins of the tumor-bearing animals decreased, there was an increase in serum protein activity which then decreased as the tumor tissue continued to gain in isotopic activity. The data suggested that the protein-depleted animals had a decreased rate of synthesis of liver nuclear and serum albumin proteins. The data also indicated a rapid synthesis of nuclear protein in the tumors of tumor-bearing animals. The author wishes to express appreciation to Miss Zina Sapankevych and Mr. Albert Schnerring who assisted in various phases of this study.

Effect of Amino Acid Levels on a Cell-Free System for Protein Synthesis

Summary Cell sap must be passed through Sephadex G-25 and then dialyzed to remove all of the amino acids. The cell-free system for protein synthesis has an optimal amino acid requirement which is approximately the same level as that observed in normal cell sap and the absence or excess of amino acids can markedly inhibit the rate of protein synthesis in the ribosomal-dependent system. In the nonribosomal system, the incorporation rate as well as the amino acid requirement are low.

Size distribution and counting of liver nuclei by an electronic particle counter.

Summary A procedure is described that allows rapid counting and sizing of liver nuclei. A good correlation exists between the degree of liver polyploidy and nuclear size. Both of these parameters increase as a function of age.

Distribution of P32 following the injection of TEPA in rats.

Summary The distribution of P32 following the injection of tagged TEPA∗ resulted in a fairly uniform distribution of P32 activity throughout the tissues of the body, but there was a greater concentration in the testes and a smaller concentration in bone as compared with injection of inorganic phosphate. There was a gradual accumulation of P32 in the spleen over a period of 30 hours following injection of TEPA∗, a result not observed with inorganic phosphate. Approximately 60% of the P32 activity in serum or plasma was associated with the globulin fraction, the remainder being in solution after precipitation of all proteins. About 20% of P32 was associated with nuclei and/or relatively heavy cellular components from liver, testes, and tumor tissue, most of the remaining activity being found in the protein-free filtrate. Some 65% of the activity was excreted over a period of 30 hours.