Investigation of Whalebone from the Miocene Kovran Locality (Kamchatka Krai,Russia)

New information on the microstructures, general morphology, and features of preservation of plates of a whalebone from the Miocene Kovran locality in the Kamchatka Peninsula are provided. The plates have a chevron-like bend which is absent in extant Balaenopteridae, Balaenidae, and Eschrichtiidae. This shape is possibly related to the filtration mechanism characteristic of these whales.     

Immobilized Yeast Membranes as Biocatalysts for Sucrose Inversion

Yeast membranes were obtained by autolysis of various strains with relatively high invertase activity. Heterogeneous biocatalysts for sucrose inversion were made of the yeast membranes and granulated carbon-containing supports made of common natural materials: expanded clay aggregate (ECA), sapropel, and lignin. The properties of these biocatalysts were studied. It was shown that the biocatalyst activity and stability of the immobilized yeast membranes increased with reference to the initial ECA, independent of the morphology of the carbon layer synthesized on the support surface. Heterogeneous biocatalysts prepared by adsorption of yeast membranes on sapropel had the greatest activity and stability, whereas lignin-based biocatalysts were relatively unstable.__________Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 4, 2005, pp. 454–459.Original Russian Text Copyright © 2005 by Kovalenko, Perminova, Plaksin, Komova, Chuenko, Rudina.     

Chemical Synthesis and Properties of Long-Chain Alkoxymethyl-Nucleobase Derivatives

Abstract

New nucleobase derivatives were synthesized, containing both octyloxymethyl (LCA8) and octadecyloxymethyl (LCA18) substituents at N¹ position of pyrimidine and N⁹ of purine. These substances were studied with respect to the formation of supramolecular structures, i.a. molecular associates as the result of noncovalent interactions. Special attention has been paid to complex formation. The properties of these molecules were investigated by DSC and polarizing microscopy.     

Effects of alpha-tocopherol derivatives on natural quinone levels in the tissues of vitamin E deficient rats]

The effects of alpha-tocopherol and its derivatives (alpha-tocopherylquinone, its short-chained analog--alpha-tocopheronolactone--and short-chained alpha-tocopherylacetate) on the levels of ubiquinone, its cyclic isomer--ubichromenol--and vitamin E in the liver and heart of vitamin E-deficient rats were studied. After injection of alpha-tocopherol derivatives the levels of ubichromenol and ubiquinone in rat liver and heart were increased, while their ratio was decreased. alpha-Tocopheronolactone was found to exert the strongest action, which is probably due to its direct effect on ubiquinone metabolism in rat tissues.     

Erroneous information in the epidemiological surveillance of hepatitis B

False positive results obtained in the determination of the immune markers of hepatitis A by the methods of the passive reverse hemagglutination test and the enzyme immunoassay distort the course of the registration of the epidemic process and deteriorate the quality of the antiepidemic measures ensured to the population. The necessity of the standardization of available test systems is postulated.