Maturation of Human Herpesvirus 6A Glycoprotein O Requires Coexpression of Glycoprotein H and Glycoprotein L

Glycoprotein O (gO) is conserved among betaherpesviruses, but little is known about the maturation process of gO in human herpesvirus 6 (HHV-6). We found that HHV-6 gO maturation was accompanied by cleavage of its carboxyl terminus and required coexpression of gH and gL, which promoted the export of gO out of the endoplasmic reticulum (ER). Finally, we also found that gO was not required for HHV-6A growth in T cells.     

Isolation and characterization of a cDNA encoding mitochondrial chaperonin 10 from Arabidopsis thaliana by functional complementation of an Escherichia coli groES mutant

Chaperonin (Cpn) is one of the molecular chaperones. Cpn10 is a co-factor of Cpn60, which regulates Cpn60-mediated protein folding. It is known that Cpn10 is located in mitochondria and chloroplasts in plant cells. The Escherichia coli homologue of Cpn10 is called GroES. A cDNA for the Cpn10 homologue was isolated from Arabidopsis thaliana by functional complementation of the E. coli groES mutant. The cDNA was 647 bp long and encoded a polypeptide of 98 amino acids. The deduced amino acid sequence showed approximately 50% identity to mammalian mitochondrial Cpn10s and 30% identity to GroES. A Northern blot analysis revealed that the mRNA for the Cpn10 homologue was expressed uniformly in various organs and was markedly induced by heat-shock treatment. The Cpn10 homologue was constitutively expressed in transgenic tobaccos. Immunogold and immunoblot analyses following the subcellular fractionation of leaves from transgenic tobaccos revealed that the Cpn10 homologue was localized in mitochondria and accumulated at a high level in transgenic tobaccos.     

Dystrophin in rod spherules; submembranous dense regions facing bipolar cell processes

 It is known that the retina contains the protein dystrophin in the ribbon synapse, but the ultrastructural analysis is not yet fully elucidated. Our previous study reported that dystrophin is localized under the rod cell membranes in rat retinas. In the present study, we have investigated the relationship between dystrophin-rich regions of rod cell membranes and other neuronal processes in mouse retinas with a monoclonal antibody raised against the human dystrophin C-terminus. Immunoblotting, immunofluorescence stainings, and immunoelectron microscopy were employed. Immunoblotting analysis indicated that mouse retinas possessed some of the dystrophin isoforms of approximately 260 kDa, 140 kDa, and 70 kDa molecular weight. Confocal images showed a punctate appearance in the outer plexiform layer, as previously described. Immunoelectron microscopy showed that dystrophin immunoreactive products were always observed at submembranous dense regions of the rod spherule abutting bipolar processes. These results suggest that retinal dystrophin may be closely involved in signal transmission from rods to bipolar cells. Accepted: 7 May 1997     

Inhibition of chromosome repair by caffeine or isonicotinic acid hydrazide on chromosome damage induced by mitomycin C in human lymphocytes

The frequency of interchromatic exchanges induced by mitomycin C in cultured human lymphocytes was markedly lowered in the presence of caffeine or isonicotinic acid hydrazide (INH) during a post-treatment period. The autoradiographic experiment showed that the decrease in the exchange frequency did not result from delaying or cell-killing effects by the post-treatment with caffeine or INH. Therefore, it may deduced that the exchange formation closely related to a process sensitive to caffeine or INH.     

The Electrophoretical Analysis of Esterase and Catalase and Its Use in Taxonomical Studies of Mycobacteria

The zymogram patterns of esterases and catalases of mycobacterial strains were studied using the thin layer agar electrophoresis. Though there were some variations, Mycobacterium hominis, M. bovis, M. kansasii, M. fortuitum, M. runyonii, M. avium, M. phlei and M. smegmatis seemed to show species-specific patterns consisting of 2 to 6 esterase bands and one or more catalase bands. The patterns of scotochromogens and nonchromogens were rather variable.     

Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components

The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS² revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides.     

Identification of N-substituted 8-azatetrahydroquinolone derivatives as selective and orally active M1 and M4 muscarinic acetylcholine receptors agonists

We designed and synthesized N-substituted 8-azatetrahydroquinolone derivatives as selective M₁ and M₄ muscarinic acetylcholine receptors agonists. Optimization of selected derivatives led to the discovery of compound 7 as a highly potent M₁ and M₄ agonist with weak hERG inhibition. Oral administration of compound 7 improved psychosis-like behavior in rats.