Uraniosomes produced in cultured rabbit kidney cells by uranyl acetate

Cultured rabbit kidney cells were exposed to uranyl acetate. This produced single-membrane-bound presumably lysosomal bodies (called 'uraniosomes') containing electron-dense crystals in the cultured cells. Similar crystalline deposits were seen in extracellular locations also. All uraniosomes and extracellular uranium deposits analyzed by electron-probe x-ray analysis were found to contain uranium, potassium, calcium and phosphorus. Traces of sulphur were detected in some but not all uraniosomes and extracellular uranium deposits.     

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.     

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.     

Presence de Chitinozoaires dans les calcaires siluro-devoniens de la Sierra Negra (Pyrenees centrales espagnoles)

A stratigraphical and paleontological study of the Silurian in the Benasque area of the high Pyrenees has made it possible to assign an Upper Pridolian age to certain limestones which occur near the top of a thick and monotonous serie of black shales. These limestones yeiled some remarkably well preserved chitinozoa together with some conodonts, orthocerases and pelecypods.     

CHARACTERIZATION AND PROTEIN ANALYSIS OF MYELIN SUBFRACTIONS IN RAT BRAIN: DEVELOPMENTAL AND REGIONAL COMPARISONS

—Myelin preparations from the whole brains of 16-day-old rats and from cortical regions and brainstem, respectively, of 40-day-old rats were separated into light, medium and heavy subfractions on a discontinuous sucrose gradient by a procedure previously used for whole adult rat brain (Matthieu, et al., 1973). The total dry weight of myelin recovered from the 16-day-old rats was only 2·4mg/g fresh brain in comparison to 20 mg from adult brains. In 16-day-old rat brains, the percentage of the total myelin protein in the light fraction was higher than that found in adult brains; the percentage in the medium fraction was only one-third that in adults; while the percentage in the heavy fraction was about the same at both ages. The heavy fraction from the 16-day-old rats contained less basic protein and proteolipid than the light fraction, and the levels of the 2′3′-cyclic nucleotide 3′-phosphohydrolase (CNP) and glycoprotein were less than half those in the light and medium fractions. Double labelling experiments with radioactive fucose indicated that the major labelled glycoprotein in the heavy and medium fractions had a slightly higher apparent mol. wt than that in the light fraction. Electron microscopy showed much readily identifiable, compact myelin in the light and medium fractions from the 16-day-old rats, whereas the heavy fraction contained more single membranous structures and much less multilamellar myelin. The yield of myelin/g fresh wt from brainstem of 40-day-old rats was 4-fold higher than from cortical regions, and the percentage recovered in the light fraction was greater in the brainstem. In both regions basic proteins decreased from the light to the heavy fraction, whereas high mol. wt proteins, the glycoprotein and CNP increased. The biochemical and morphological results suggest that in both 16-day-old and young adult rats the light fraction is enriched multilamellar, compact myelin. In contrast, the heavy fraction at both ages is enriched in loose, uncompacted myelin and myelin-related membranes, although the heavy fraction from 16-day-old rats also may be substantially contaminated with membranes which are unrelated to myelin.     

Unprecedented Therapeutic Potential with a Combination of A2A/NR2B Receptor Antagonists as Observed in the 6-OHDA Lesioned Rat Model of Parkinson's Disease

In Parkinson''s disease, the long-term use of dopamine replacing agents is associated with the development of motor complications; therefore, there is a need for non-dopaminergic drugs. This study evaluated the potential therapeutic impact of six different NR2B and A_2A receptor antagonists given either alone or in combination in unilateral 6-OHDA-lesioned rats without (monotherapy) or with (add-on therapy) the co-administration of L-Dopa: Sch-58261+ Merck 22; Sch-58261+Co-101244; Preladenant + Merck 22; Preladenant + Radiprodil; Tozadenant + Radiprodil; Istradefylline + Co-101244. Animals given monotherapy were assessed on distance traveled and rearing, whereas those given add-on therapy were assessed on contralateral rotations. Three-way mixed ANOVA were conducted to assess the main effect of each drug separately and to determine whether any interaction between two drugs was additive or synergistic. Additional post hoc analyses were conducted to compare the effect of the combination with the effect of the drugs alone. Motor activity improved significantly and was sustained for longer when the drugs were given in combination than when administered separately at the same dose. Similarly, when tested as add-on treatment to L-Dopa, the combinations resulted in higher levels of contralateral rotation in comparison to the single drugs. Of special interest, the activity observed with some combinations could not be described by a simplistic additive effect and involved more subtle synergistic pharmacological interactions. The combined administration of A_2A/NR2B-receptor antagonists improved motor behaviour in 6-OHDA rats. Given the proven translatability of this model such a combination may be expected to be effective in improving motor symptoms in patients.     

Enzyme and protein composition of myelin isolated in the presence of EGTA

The efficiency of ethyleneglycol-bis (β-amino-ethyl ether) N,N′-tetra-acetic acid (EGTA) in removing possible contamination from myelin was tested. Myelin fractions were isolated in the presence or absence of EGTA. An axolemma-enriched fraction was also prepared. Gel electrophoresis showed no important alteration of the protein pattern of myelin treated with EGTA. Only a minor band of about 41,000 daltons was selectively removed when EGTA was used during the two density gradient and differential centrifugation steps. EGTA, when used in the final washes, did not remove this band. It was absent from axolemma-enriched fractions. Different hypotheses are considered to explain these findings.     

[3 5S]Sulfate incorporation into myelin glycoproteins II. Peripheral nervous tissue

The in vivo incorporation of [^{3 5}S]sulfate, [³H]fucose and [³H]leucine into sciatic nerve myelin was investigated. Polyacrylamide gel electrophoresis of the proteins indicated that the ^{3 5}S-labeling of proteins occurred almost exclusively in the major myelin protein. A smaller myelin glycoprotein migrating just ahead of the major one was labeled with [³H]fucose but did not incorporate ^{3 5}S to a detectable extent. There was little or no ^{3 5}S associated with basic proteins on polyacrylamide gels when the proteins were extracted with chloroform/methanol. Fucose-labeled myelin glycoproteins were converted to glycopeptides by pronase digestion. The glycopeptides gave a single peak on Sephadex G-50 in which the ³H and ^{3 5}S coincided. The association of ^{3 5}S with glycopeptides was not caused by binding of sulfatide or free inorganic sulfate. This study shows that the major myelin protein in the sciatic nerve of the rat is glycosylated and sulfated.     

Microwave-assisted Synthesis of Novel Thiazolocarbazoles and Evaluation as Potential Anticancer Agents. Part III

Novel 6-substituted thiazolocarbazole derivatives have been synthesized under microwave irradiation via the corresponding imino-1,2,3-dithiazoles. In vitro antitumor potential of these polyheterocyclic compounds was evaluated. Among all the tested thiazolocarbazoles, compound 10 is the most effective in inhibiting cell growth.