Uridylation of U6 RNA in a nuclear extract in Ehrlich ascites tumor cells

The uridylation of U6 RNA in a nuclear extract of Ehrlich ascites tumor cells was examined. This reaction required ATP or GTP, although these nucleotides were not incorporated into U6 RNA itself. ATP and GTP could be replaced by their nonhydrolyzable analogues ATP gamma S and GTP gamma S. Therefore, hydrolysis of ATP or GTP is not necessary for the uridylation of U6 RNA, indicating that these nucleotides are effectors of this reaction. By chromatographies of a nuclear extract of Ehrlich ascites tumor cells on phosphocellulose and DEAE-cellulose, U6 RNA could be separated from an enzyme adding a uridine residue(s) to this RNA.     

Induced synthesis of immunoglobulin messenger RNA accompanies induction of immunoglobulin production in cultured mouse spleen cells.

Immunoglobulin kappa type light chain mRNA (Lkappa mRNA) accumulated in parallel with secretion of immunoglobulin M in cultured mouse spleen cells activated by lipopolysaccharide. Actinomycin D suppressed the accumulation of kappa chain mRNA completely without affecting the degradation rate of kappa chain mRNA. The half life of kappa chain mRNA was about 9 h. Available evidence indicates that lipopolysaccharide stimulates de novo synthesis of kappa chain mRNA. The accumulation of kappa chain mRNA was markedly suppressed by inhibitors of DNA or protein synthesis such as hydroxyurea, cytosine arabinoside and cycloheximide.     

Effect of cycloheximide on the levels of nuclear HMG proteins in rat liver

Within 30 minutes of administration of cycloheximide to rats, rRNA synthesis in isolated liver nuclei was inhibited by approximately 50%. The nuclear contents of high mobility group (HMG) proteins, including HMG 1, 2 and 14, were found to be decreased in parallel with the inhibition of RNA synthesis while the contents of the total cellular HMG proteins remained unchanged. The role of HMG proteins in the regulation of RNA synthesis is discussed.     

Morphological variations of the cranium within the genusLeontopithecus

Multivariate analysis methods were applied to the cranial measurements ofLeontopithecus. InLeontopithecus chrysomelas, the face is generally narrow and the cranial shape is relatively unique. Especially, the male has extremely narrow face and quite unique cranial shape amongLeontopithecus. Leontopithecus rosalia has the broad face compared with the other species. The cranial size ofL. rosalia is as large as that ofL. chrysomelas. Male ofLeontopithecus chrysopygus is the largest in overall size of the cranium, and has the widest braincase.     

Biological and Biochemical Characterization of Macrophage Activating Factor (MAF) in Murine Lymphocytes: Physicochemical Similarity of MAF to Gamma Interferon (IFN-γ)

During the course of an investigation designed to separate macrophage activating factor (MAF) activity from interferon (IFN) antiviral activity in the lymphokine-rich fraction (LKF) produced by stimulation of murine splenic cells with concanavalin A (Con A), we found molecular evidence for the similarity of the two activities. MAF activity was expressed as the rate of inhibition of intracellular growth of Salmonella typhimurium in macrophages based on the linear correlation between relative MAF activity and LKF concentration. The antiviral substance in LKF was identified as IFN-γ based on the observation that its activity was inactivated at pH 2 and neutralized with anti-mouse IFN-γ serum but not with anti-mouse IFN-α/β serum. MAF and IFN antiviral activities displayed identical sensitivity to pH 2 and temperature. Further, neither activity was affected by β-mercapto-ethanol, but both were inactivated by guanidine hydrochloride and by sodium dodecyl sulfate, suggesting that the structures related to conformation of the protein of the two molecules may be similar. In affinity chromatography of the LKF on a Con A-Sepharose column, MAF and IFN activities were found in both the nonadsorbing (F I) and adsorbing (F II) fractions. However, the rates of F II of MAF and IFN activities increased proportionally when the sample was applied on a column of higher capacity, suggesting that the molecular structure of the mannose-containing glycosyl moiety of the two molecules may also be similar. Moreover, the intact or modified form of MAF and IFN activities of different LKF preparations showed a strong correlation, indicating that the production and denaturation of MAF activity were proportional to those of IFN antiviral activity. The results of this study provide strong evidence that MAF and IFN antiviral activities may reside in virtually the same molecular species.