Ellis T. Bolton

Amino acid analog incorporation into bacterial proteins

The amino acid analogs norleucine and para-fluorophenylalanine are shown to be incorporated into the proteins of E. coli. Analysis of proteins by an ion-exchange column showed that the proteins formed in the presence of the analogs are not radically different molecular species but are physicochemically similar to the proteins normally synthesized. The substitution of norleucine for methionine in the bacterial proteins was shown to occur in the same proportions in all of the “protein classes” resolved by the ion-exchange column.

Complementary RNA in Nucleus and Cytoplasm of Mouse Liver Cells

The rapidly labeled RNA from both the nuclei and cytoplasm of mouse liver cells can be bound specifically to mouse DNA. The bound fraction differs in base composition and metabolic stability from the bulk RNA. There is considerable cross reaction between this RNA and the DNA obtained from calf thymus.

Polyoma Virus Genetic Material in a Virus-Free Polyoma-Induce Tumor

The DNA-agar technique for homology studies was used to investigate of the viral genetic material. Complemetary found between the polyoma DNA and the DNA of several mammalian species. The increased complementarity of the polyoma DNA to the DNA of polyoma-induced tumor reflects an increased frequency of common poly-nucleotide sequences in the tumor DNA.

Mammalian Viruses and Rickettsiae Their purification and recovery by cellulose anion exchange columns has significant implications.

Techniques of column chromatography with cellulose ion exchangers have been successfully applied to mammalian viruses and rickettsiae. Recovery of virus is excellent, and appreciable purification in terms of phosphorus and protein removal has been demonstrated. Elution characteristics of poliovirus (types 1, 2, and 3), and Coxsackie A9 virus are similar, whereas those of ECHO-13 and Colorado tick fever differ from them as well as from each other. Elution diagrams of preparations of ECHO-13 and polio 2 viruses grown on P32-labeled tissue cultures show a high degree of correlation between the distribution of titratable virus and the distribution of radioactivity. A single adsorption and elution of Q fever or epidemic typhus fever rickettsiae results in a striking degree of purification, as demonstrated by electron micrographs. The chromatographic behavior of the animal viruses and rickettsiae appears to depend more upon the chemical nature of the surfaces of these infectious agents than upon their size. The chromatographic procedure described may prove useful in the preparation of purified, P32-labeled, fully infectious animal viruses for further fundamental research. It may also prove useful for the removal of unwanted host materials in the preparation of vaccines.

The use of metabolic pools of purine compounds for nucleic acid synthesis in yeast

Abstract Exogenous purines are incorporated first into metabolic pools and thence into nucleic acids by exponentially growing Candida utilis. Kinetic studies show that a purine pool, whose size is determined by the amount of purine in the medium, forms first. This pool contributes material to a nucleotide pool whose pool size is independent of the purine concentration in the medium. Conversion of adenine to guanine occurs in the nucleotide pool which serves as a preferred source of purine for nucleic acid synthesis.

The Evolution of Polynucleotides

Publisher Summary This chapter discusses the evolution of polynucleotides. Comparisons of amino acid sequences, enzymatic activities, and immunological properties of macromolecules shows only a few of the many attributes of the organisms under consideration. Specific affinities observable among various DNA are indicative of qualities of the whole organism. This chapter presents the findings that are restricted to the DNA–DNA relationships among vertebrates with emphasis on the primate group. The primates were chosen for the present study because of the interest in their relationships and because of the backlog of information concerning this group from a variety of studies that range from the molecular to the sociological. The implications of the data presented for understanding the mechanism of organic evolution urge the experiments that can distinguish between the alternative interpretations of evolutionary divergence or assess their relative importance, should they both be applicable.

Utilization of purine and pyrimidine compounds in nucleic acid synthesis by Escherichia coli.

Abstract Utilization of purine and pyrimidine compounds by growing Escherichia coli, B , was studied with the aid of 14 Co 2 . It was found that adenine and adenosine were efficiently utilized for nucleic acid synthesis in preference to 14 CO 2 and were converted to bacterial guanine. Yeast adenylic acid was relatively poorly utilized. Guanine, guanosine, and guanylic acid were used as a source of bacterial guanine but were poorly converted to adenine. Cytosine, cytidine, cytidylic acid, uracil, uridine, and uridylic acid were utilized as sources for both bacterial cytosine and uracil. No utilization of thymine, thymidine acid or oxotic acid could be demonstrated by the method used.

The labeling of bacterial cells with S35 for the production of high specific activity compounds.

Summary These results demonstrate that the 23.4 mc. of bound sulfur (Table I) taken up by 0.15 ml. of cells provide a means of specifically labeling both methionine and cystine (2×10 9 counts/sec./mg. of sulfur) without interference from excessive radiation exposure of the cells. It is also apparent that extremely small numbers of E. coli cells can be labeled and detected.