Induction of interleukin 1 messenger RNA and translation in oocytes

Macrophages and P388D1 murine cultured cells produce interleukin 1 (lymphocyte-activating factor) when stimulated with lipopolysaccharide or other agents. Poly A+ RNA extracted from either type of stimulated cells and injected into Xenopus oocytes causes synthesis of material with the biologic and biochemical properties of interleukin 1. It potentiates lectin-mediated thymocyte proliferation, and it has the molecular dimensions of interleukin 1, as determined by gel exclusion chromatography. RNA from either cell type causes the synthesis of interleukin 1 with an isoelectric point of 4.8 to 5.0. RNA prepared from unstimulated macrophages or P388D1 cells does not cause interleukin 1 production by oocytes. We conclude that the amount of interleukin 1 mRNA increases greatly after stimulation of either cell type, and oocytes carry out any modifications of the polypeptide necessary for activity. The kinetics of interleukin 1 mRNA accumulation and of interleukin 1 production by macrophages and P388D1 cells are compared.

Increased synthesis of glutathione S-transferases in response to anticarcinogenic antioxidants. Cloning and measurement of messenger RNA

Glutathione S-transferase activities in mouse hepatic cytosols are elevated as much as 11-fold following the administration of BHA (2(3)-tert-butyl-4-hydroxyanisole), a widely used antioxidant food additive. Ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) and disulfiram [bis(diethyldithiocarbamyl)disulfide] also enhance the activities of glutathione S-transferases and certain other enzymes. Each of these compounds protects rodents against mutagenic and carcinogenic metabolites. A major (pI 8.7) and a minor (pI 9.3) component of the family of mouse hepatic glutathione S-transferases have been purified to homogeneity. These transferases are immunologically cross-reactive, and have a high degree of NH2-terminal sequence homology (but are not identical). The enzymes differ in a number of molecular and catalytic properties. The transferases are 12-fold elevated by dietary BHA as demonstrated by immunotitration. The mRNA for the major glutathione S-transferase is increased more than 20-fold in the liver RNA of BHA-fed mice, as determined by translation of total liver mRNA and characterization of the products by immunoprecipitation and sodium dodecyl sulfate-gel electrophoresis or by two-dimensional gel electrophoresis. A cDNA plasmid complementary to glutathione S-transferase mRNA was constructed. Translation of liver mRNA selected by hybridization with this plasmid gave products similar to or identical with glutathione S-transferase polypeptides. The cDNA insert has been partially sequenced and its orientation has been determined. Its sequence corresponds to the NH2-terminal region (beginning at residue 9) of the amino acid sequence of the glutathione S-transferase with pI 9.3. Hybridization of the 32P-labeled cDNA plasmid with total liver RNA indicates a 26-fold increase in homologous mRNA in response to the feeding of BHA.

Oxidation of N-methyl-gamma-tocopheramine to a nitroxide

An unstable nitroxide identified by electron paramagnetic resonance spectra was obtained by oxidation of N-methyl-gamma-tocopheramine with peroxide and also by ultraviolet photooxidation.

Electron spin resonance study of melanin treated with reducing agents

The electron spin resonances (ESR) of several native and modified melanins have been determined. Melanins isolated from black wool and synthesized from 3,4-dihydroxyl-L-phenylalanine (L-DOPA) and tyrosine all show similar ESR signals. Modification of the isolated melanins by treatment with reducing agents causes some lightening in color and slight changes in the ESR spectra. Lithium and liquid ammonia (Birch) reduction applied to melanins from wool and L-DOPA gave very different results, as reflected by ESR spectra, but in both cases the changes were much greater than those produced by other treatments. In general, reductive treatments in nonaqueous media in the presence of metals increase the free radical content and line width, whereas treatment in aqueous media resulted in decreased free radical content. These observations are consistent with a melanin pigment which is an irregular polymer and has unpaired electrons localized on different but similar monomer units.