Problems of Acyl Migration in Lipase-Catalyzed Enantioselecttve Transformation of Meso-1,3-Diol Systems

In the enantioselective hydrolysis of the di-O-acetyl derivatives of meso-1,3-diol catalyzed by lipases, racemization of the monoacetate products occurs due to non-enzymatic general base-catalyzed acyl migration. The rate of acyl migration increases with increase of pH and buffer concentration. A mechanism of the migration has been proposed to proceed through a six-member ring transition that accounts for the experimental results. The acyl migration, however, was not observed in the enantioselective transesterification of meso-1,3-diols in neutral organic solvents.     

Specific refractoriness of adenylate cyclase in skin to epinephrine,prostaglandin E,histamine and AMP

The cyclic AMP level in pig skin (epidermis) increases markedly after incubation with epinephrine, prostaglandin E, histamine or adenosine 5′-monophosphate. This increase is transient and “spiking” is the consistent response to these four stimulators. The “spiking” is due to a non-responsiveness or refractoriness which develops within minutes and is specific to any one stimulating hormone but not to the others. The addition of inhibitors of protein syntheses did not prevent the development of the refractoriness. Adenylate cyclase and phosphodiesterase activities measured in skin homogenates prepared from skin samples taken before, during and after the “spiking” did not change significantly. The hormone-induced refractoriness in this skin system appears to be due to a specific, localized loss of function of the adenylate cyclase system.     

Differences in rapid eye movement sleep behavior disorder manifestation between synucleinopathies and tauopathies

Rapid eye movement sleep behavior disorder (RBD) frequently occurs in synucleinopathies including multiple system atrophy, Parkinson’s disease, and dementia with Lewy bodies despite the clinical course of RBD being different between these disorders. Comparatively, the existence of RBD symptoms is relatively rare in patients with progressive supranuclear palsy, a tauopathy showing atypical parkinsonism compared with Parkinson’s disease. Moreover, in patients with Alzheimer’s disease, which is another tauopathy, RBD symptoms are less frequent than dementia with Lewy bodies, although both disorders share commonalities in terms of the existence of cortical dementia. Thus, RBD is thought to be relatively specific to synucleinopathies.

     

Synthesis of (S)-2-Hydroxy-β-ionone,Employing (S)-3-Hydroxy-2,2-dimethylcyclohexanone as the Chiral Starting Material

(S)-2-Hydroxy-β-ionone of 96% e.e. was synthesized from (S)-3-hydroxy-2,2-dimethyl cyclohexanone, which was easily obtained by the baker’s yeast reduction of 2,2-dimethylcyclohexane-l,3-dione.     

Purification and characterization of membrane-bound alcohol dehydrogenase from Acetobacter polyoxogenes sp. nov.

Summary Membrane-bound alcohol dehydrogenase (ADH) was purified from the membrane fraction of an industrial-vinegar-producing strain, A. polyoxogenes sp. nov. NBI1028 by solubilization using Triton X-100 and subsequent column chromatography on DEAE-Sepharose CL-6B and hydroxyapatite. The purified enzyme was homogeneous on polyacrylamide disc gel electrophoresis (PAGE). Upon sodium dodecyl sulphate-PAGE, the enzyme showed the presence of two subunits with a molecular mass of 72 000 daltons and 44 000 daltons, respectively. The small subunit was identified as cytochrome c. In addition, absorption and fluorescence spectra showed the the presence of pyrroloquinoline quinone in the purified ADH. The ADH preferentially oxidized aliphatic alcohols with a straight carbon chain except for methanol. Formaldehyde and acetaldehyde were also oxidizable substrates. The apparent K _m for ethanol was 1.2 mM. The optimum pH and temperature were 5.0–6.0 and 40°C, respectively. p-Chloromercuribenzoic acid and heavy metals such as CuSO₄ were inhibitory to the enzyme activity. Ferricyanide was effective as an electron acceptor.Offprint requests to: M. Fukaya     

Synthesis of Sphingosine Analogs with Acyclic Terpenoidal Carbon Skeleton

A simple and general synthetic method is described for erythro- and threo-forms of 2-amino-1,3-diols with an acyclic terpenoid-type side chain. ¹³C-NMR data are given for the triacetyl and N-acetyl derivatives of the synthetic erythro- and threo-2-amino-1,3-diols.     

A Novel Enhanced Green FluorescentProtein-Expressing NOG Mouse for Analyzingthe Microenvironment of Xenograft Tissues

The interaction between transplanted cells and host tissues is important for the growth and maintenance of transplanted cells. To analyze the mechanisms of these interactions, a systemic fluorescent protein-expressing mouse is a useful recipient. In this study, we generated a novel NOG strain, which strongly expresses enhanced green fluorescent protein (EGFP; PgkEGFP-NOG), especially in the liver, kidney, gastrointestinal tract, and testis. Because the host tissues expressed EGFP, xenotransplanted human cancer cells were clearly identified as EGFP-negative colonies in PgkEGFP-NOG mice. Immunohistochemical analysis revealed that EGFP-expressing stromal tissues formed a complicated tumor microenvironment within xenograft tissues. Moreover, a similar microenvironment was observed in human iPS cell-derived teratomas. Collectively, these results indicated that a suitable microenvironment is essential for the growth and maintenance of xenotransplanted cells and that PgkEGFP-NOG mice represent a useful animal model for analyzing the mechanisms of microenvironment formation.