Reduced hepatic alpha-tocopherol content after long-term administration of ethanol to rats

We have studied the effects of long-term administration of ethanol on the distribution and pharmacokinetics of alpha-tocopherol. In rats fed ethanol (35% of total energy) for 5-6 weeks concentration of alpha-tocopherol in whole liver was reduced by 25% as compared to the pair-fed controls (P less than 0.003). This reduction was significant in the parenchymal cells (28%, P less than 0.004), whereas no significant difference was observed for the nonparenchymal cells. Mitochondrial alpha-tocopherol content was reduced by 55% in the ethanol-treated rats as compared to the controls (P less than 0.002), whereas no significant difference was observed in microsomes, light mitochondria or cytosol. The serum levels of alpha-tocopherol showed no significant difference between the groups. When in vivo labeled chylomicron alpha-[3H]tocopherol was injected intravenously to anesthetized rats, we found a significant increase in serum half-life of alpha-tocopherol in the ethanol-treated group as compared to the controls (P less than 0.025). Hepatic alpha-[3H]tocopherol content was similar in the two groups 24 h after injection.     

Inducible DNA polymerase I synthesis in a UV hyper-resistant mutant of Escherichia coli

A mutant of Escherichia coli which is more resistant to shortwave UV light than its wild-type parent strain and which can synthesise DNA polymerase I constitutively has been further analysed. It carries two mutational alleles which are located about 1.5 min apart and cotransducible by P1 with the argH locus. The two mutational alleles have been segregated and their analysis shows that one of them is responsible for UV hyper-resistance whereas the other mutation confers UV sensitivity. Recombinant plasmids carrying various sections of the polA regulatory region, linked to a galK gene, were introduced into the mutant strains. Analysis of galactokinase shows that the enzyme activity in the UV hyper-resistant mutant is increased. The results suggest that the synthesis of DNA polymerase I in E. coli is inducible.     

Estimation of tyrosine-40-DNA distance in the filamentous phage Pf1 by analysis of its intrinsic fluorescence properties

Iodination of the exposed Tyr-25 in the coat protein decreases the fluorescence intensity of the filamentous phage Pf1 to less than 3% of its original fluorescence. If one assumes that the total residual fluorescence originates from the non-iodinated, buried Tyr-40, one can estimate the distance between Tyr-40 and the DNA bases in Pf1 to be less than 7 A, making use of the Foerster law for fluorescence energy transfer. The result is consistent with the idea that Tyr-40-DNA interaction is responsible for the unusually large axial base separation in Pf1-DNA.     

Wingea,a new genus of the Saccharomycetaceae

The yeast species previously described asPichia robertsii v. d. Walt has been transferred to the new genusWingea. The diagnosis for the genus is given.     

Preferential expression of cellular retinoic acid binding protein in a subpopulation of neural cells in the developing mouse embryo

The cellular retinoic acid binding protein is thought to be involved in the retinoic-acid-mediated signal transduction pathway. We have isolated the mouse cellular retinoic acid binding protein cDNA from an embryonal-carcinoma-derived cell line by using differential cDNA cloning strategies. In situ hybridization on sections of mouse embryos of various developmental stages indicated that the cellular retinoic acid binding protein gene, which we localized on mouse chromosome 9, is preferentially expressed in a subpopulation of neurectodermal cells. This restricted expression pattern suggests an important role for cellular retinoic acid binding protein in murine neurogenesis.