Distribution of lipid synthesizing enzymes, 2′,3′-cyclic nucleotide 3′-phosphodiesterase,and myelin proteins in rat forebrain subfractions during development

The distribution of UDP-galactose: ceramide galactosyltransferase (CGalT) was studied in subcellular fractions of rat forebrain during development using zonal centrifugation on linear gradients. Specialized subfractions: SN 1, a microsomal fraction, SN 4, a myelin-related fraction, and purified myelin were also used for this study. For comparison, two microsomal lipid synthesizing enzymes, a myelin-specific enzyme, 2,3-cyclic nucleotide 3-phosphodiesterase and myelin proteins were measured in the same subfractions. UDP-glucose: ceramide glucosyltransferase and cerebroside sulfotransferase were confined to microsomes. CGalT was ferase and cerebroside sulfotransferase were confined to microsomes. CGalT was localized in microsomes, but also in myelin and myelin-related fractions. The developmental change in distribution of CGalT in adult animals toward myelin containing fractions could indicate that the replacement of galactosylceramide in compact myelin could be carried out in close proximity to compact myelin (mesaxon, paranodal loops) rather than in the distant oligodendrocyte perikaryon.     

Characterization ofκ-casein and keratin domains in fibrinogen

Summary Following the observation of a close sequence homology between the N-terminal moiety of the -chain of fibrinogen with large parts of-casein, the occurrence of a keratin domain in the middle section of the Achain is suggested.     

Hybridization of a mouse T-cell lymphocyte line (HB1) with a polyoma virus-transformed mouse fibroblast line

The establishment of permanent T-lymphocyte cell lines by transformation with DNA viruses has not yet been achieved. This paper reports the successful transfer of polyoma virus genome into T-lymphocyte cells by somatic hybridization. A T-lymphocyte clone, HB₁, derived from (DBA/ 2J×AKR) spleen cells, isolated in vitro by cloning in semi-solid agar, was fused with a polyoma (Py) virus-transformed fibroblast C3HPy, clone 1. The authenticity of the hybrid C3H/HB was established by chromosome and histocompatibility antigen studies. This initial population and the various clones retained T-lymphocyte characteristics such as morphological appearance, growth properties (suspension culture) and differentiation antigen (Thy 1–2). The hybrid cell line and the various clones presented all the characteristics of Py transformation. Namely, they carried the Py genome originating from the fibroblastic parent and maintained Py virus tumour-associated antigens (TSTA, TSSA and T antigens). In most respects, this hybrid population resembled the C3HPy/C11 parent and exhibited the same tumorigenicity.     

Biochemical markers in a species endangered by introgression: The red wolf

The red wolf (Canis rufus), native to much of the southeastern United States, is endangered by man's activities and by hybridization with other species of the genus Canis. The absence of diagnostic morphological markers to distinguish the red wolf from its hybrids has led to the application of the methods of biochemical genetics to this problem. The finding of a unique electrophoretically determined allele with a distribution congruent with the geographical distribution of the remaining red wolf population is reported.This research was supported by NIH Public Health Service Grants GM 19513 and CA 19311 and by the State of Texas.     

Mating-Type Effect on CIS Mutations Leading to Constitutivity of Ornithine Transaminase in Diploid Cells of SACCHAROMYCES CEREVISIAE

Cis-acting regulatory mutations have been isolated that affect L-ornithine transaminase (OTAse), an enzyme catalyzing the second step of arginine breakdown in yeast. These mutations lead to constitutive synthesis of OTAse at various levels. Two different types of mutations have been recovered, both of which are tightly linked to the structural gene (cargB) for this enzyme. One type behaves as a classical operator-constitutive mutation similar to the cargB+O---1 mutation previously described (DUBOIS et al. 1978). The second type is peculiar in two respects: the higher level of constitutive OTAse synthesis and the expression of constitutivity in diploid cells. These mutations are designated cargB+Oh. They behave as usual operator-constitutive mutations in diploid strains homozygous for mating type (a/a or alpha/alpha), but the constitutivity is strongly reduced in a/alpha diploid cells.     

Basal level of human platelet prostaglandins: PGE1 is more elevated than PGE2

Radioimmunoassays of platelet prostaglandins E₁ and F_1α in platelet rich plasma or platelet suspension, demonstrate that both PGE₁ and PGF_1α are present at higher concentrations than prostaglandins E₂ and F_2α. Gas chromatography — mass spectrometry determinations of prostaglandins E₁ and E₂ in resting washed platelets confirm this difference. Lastly, there is a greater incorporation of [1-¹⁴C] acetate into prostaglandins E₁ and F_1α compared to that into prostaglandins E₂ and F_2α.