Rat sequences of the Kirsten and Harvey murine sarcoma virus genomes: nature, origin, and expression in rat tumor RNA

Two murine sarcoma viruses, the Kirsten and the Harvey, were isolated by passage of mouse type C leukemia viruses through rats. These sarcoma viruses have genomes containing portions of their parental type C mouse leukemia virus genomes, in stable association with specific rat cellular sequences that we find to be quite likely not those of a rat type C leukemia virus. To determine if these murine sarcoma viruses provide a model relevant to the events occurring in spontaneous tumors, we have hybridized DNA and RNA prepared from rat tumors and normal rat tissues to [3H]DNA prepared from the Kirsten murine sarcoma virus. We have also hybridized these rat tissue nucleic acids to [3H]DNA prepared from a respresentative endogenous rat type C leukemia virus, the WFU (Wistar-Furth). Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected in the DNA of both tumor and normal tissues, with no evidence of either gene amplification or additional sequences being present in tumor DNA. Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected at elevated concentrations in the RNA of many rat tumors and in specific groups of normal tissues.

Purification by preparative electrophoresis and characterization of histone H2B from rat chloroleukaemia

Highly purified histone H2B from rat chloroleukaemia has been isolated by preparative electrophoresis at pH 2.7 in polyacrylamide slab gel, using the fraction F2b of Johns (Johns E. W. (1964) Biochem, J. 92, 55-59) as starting material. This histone was characterized by amino acid analysis and end groups determination. Comparative studies with homologous calf thymus histone show similarity of the amino acid compositions and of the amino terminal groups. the carboxyl terminal sequence presents two conservative substitutions.

Insoluble collagen of methylcholanthrene induced sarcoma

The insoluble collagen from methylcholanthrene induced sarcoma was isolated and characterized. It contains more glycine, hydroxyproline and acidic amino acids than normal connective tissue collagen. An anionic character of tumour collagen was stated (pI 6.1). No typical collagen subunits in this protein were found. The tumour collagen is strongly bound to acidic glycoprotein containing a significant amount of hydroxylysine. Such an insoluble complex is resistant to the dispersing action of EDTA. It dissociates during heating in concentrated urea.

In vivo testing of hypoxic radiosensitizers using the KHT murine tumour assayed by the lung-colony technique

The KHT transplantable tumour of C3H mice has been used as a model tumour for the invivo study of hypoxic cell sensitizers. Eleven sensitizers comprising four nitrofuran five nitrobenzene and two nitroimidazole derivatives, which have been shown to be effective on hypoxic mammalian cells in vitro, have been investigated. Two of these compounds, metronidazole (2-methyl-5-nitroimidazole-1 ethanol) and tinidazole (ethyl [2-(2'-methyl-5'-nitro-1'-imidazolyl) ehtyl] sulfone), showed signs of hypoxic cell-sensitization in vivo when given systemically by intraperitoneal injections. In addition, preliminary testing of the nitrobenzene NDPP (P-NITRO-3-DIMETHYL-PROPRIOPHENONE HYDROCHLORIDE) INDICATED THAT WHEN IT WAS INJECTED DIRECTLY INTO THE TUMOUR AND IRRADIATION WAS COMPLETED WITHIN TEN MINUTES AFTER INJECTION, APPRECIABLE SENSITIZATION WAS OBTAINED. More detailed studies indicated that both metronidazole at 1,500 mg/kg and tinidazole at 750 mg/kg given intraperitoneally gave an enhancement ratio of 1-5 for a chronically hyopix cell population in this solid tumour in air-breathing mice. Measures of plasma levels of metronidazole and enhancement ratios obtained in the present in vivo system seem in relative agreement with the in vitro and in vivo results of others.

[Isolation and properties of cytoplasmic 21S and 7.5S RNP-particles from rat M-1 sarcoma cells]

RNP-particles, containing components with coefficient of sedimentation 119 S, 78 S, 60 S, 40 S, 21 S and 7.5 S were prepared from cells of sarcoma M-1. After separation in sucrose gradient, physico-chemical properties of 21 S and 7.5 S particles were studied. RNA of the particles was shown to belong to the GC-type. More than 10 protein fractions were found in polyacrylamide gel electrophoresis of these particles in presence of sodium dodecyl sulphate. Some of the proteins possessed electrophoretic mobility similar to that ribosomal proteins. In CsCl2 floating density of 21 S and 7.5 S particles was equal to 1.355 g/cm-3. By means of immunodiffusion method it was shown that light RNP-particles were analogous to the ribosomes of rat liver tissue and sarcoma M-1. Incorporation of 14-C-leucine into protein and 32-P-ortophosphate into RNA within 4, 7 and 12 hrs after administration of the isotopes demonstrated metabolic stability of RNA and high activity of the protein in the RNP-particles studied.

Effect of injection of nuclear fraction from Rhodamine sarcoma on turnover of liver catalase

1) When nuclear fraction prepared from Rhodamine sarcoma (sarcoma nuclear fraction) was injected into mice three times every 24 hr, the catalase activity of the liver decreased to one-third of the original activity. 2) By the injection of sarcoma nuclear fraction into mice, the catalase activity with the soluble fraction from homogenates of the liver decreased more significantly than that with the particulate fraction from them. 3) Immunological titration proved that the decrease of catalase activity in the liver of mice injected with sarcoma nuclear fraction was brought about by decrease in the amount of catalase protein. 4) In the mice, whose liver catalase activity had been irreversibly inhibited by injection of 3-amino-1,2,4-triazole, the initial rate for the restoration of the liver catalase activity was significantly showed by further injection of sarcoma nuclear fraction. 5) When the inhibitor of catalase biosynthesis, allylisopropylacetamide, was injected into mice, the activity level of the liver catalase decreased. The extent of decrease by the injection of the inhibitor was slightly lower than that by the injection with sarcoma nuclear fraction, which was almost the same as the extent of decrease by the injection of sarcoma nuclear fraction plus allylisopropylacetamide. 6) It is conceivable that the catalase biosynthesis in the liver was inhibited by the injection of sarcoma nuclear fraction in almost the same manner as by the injection of allylisopropylacetamide. However, it is not certain whether the degradation of liver catalase was slightly stimulated by the injection of sarcoma nuclear fraction.