A phosphorbisamidite approach to the synthesis of oligodeoxyribonucleotides and their analogues

Utilities of deoxyribonucleoside 3'-O-phosphorbisdiethylamidites in the synthesis of oligodeoxyribonucleotides and their analogues are described.     

Innervation of the arteriovenous anastomoses in the dog tongue

Summary Profiles of nerve plexuses in the arteriovenous anastomoses of the dog tongue were investigated by both transmission and scanning electron microscopy. Three-dimensional morphology of the vascular nerves was examined after removal of the connective tissue components by the HCl-hydrolysis method. Tight bending and a rich nerve supply were the most characteristic features of the anastomosing channels. The tunica media consisted of an outer circular layer of typical smooth-muscle cells and an inner region containing longitudinal plicae of ramified smoothmuscle cells. The tunica adventitia was exclusively occupied by nerve bundles; fibroblasts were poorly developed. Numerous nerve bundles of variable size were coiled around the anastomosing channels, and occasional bundles ran crosswise over the U-shaped bent vessels.     

Control of the nitrile-hydrolyzing enzyme activity in Rhodococcus rhodochrous IFO 15564: preferential action of nitrile hydratase and amidase depending on the reaction condition factors and its application to the one-pot preparation of amides from aldehydes

The reaction conditions towards the preferential action of either nitrile hydratase or amidase in the harvested whole cells of Rhodococcus rhodochrous IFO 15564 were elaborated. The amidase showed higher heat tolerance than the nitrile hydratase and, at 45 °C the amidase worked exclusively. DMSO assisted the preferential action of nitrile hydratase, however, at more than 30% (v/v) addition of DMF, the nitrile hydratase activity was completely lost and only amidase worked. A one-pot chemo-enzymatic conversion of aldehydes to amides [(1) aq. NH₃, I₂, DMSO; (2) Na₂S₂O₃; (3) harvested cells of R. rhodochrous] was established. Under these reaction conditions, most of the amidase was lost, and the incubation of the firstly formed intermediates, nitriles in aq. NH₃ was responsible for the selective inhibition of amidase. The freezing of harvested cells in an exhaustively deionized environment provided a long-term preservable “ready to use” for the organic chemist.     

The Computational Studies on the Conformation-Stabilizing Factors of the Left-Handed Z-DNA

Abstract

The conformation-stabilizing factors of the left-handed Z-DNA was estimated by the molecular dynamics calculations using the various metal cations and the polyamines. We concluded the conformation-stabilizing effect of metal cation for Z-DNA was more significant than that of the polyamine by theoretically.     

A model for the mechanisms of sensitivity control in the submammalian vertebrate retina

A model is proposed for the mechanisms of sensitivity control at the outer and inner plexiform layers in the submammalian vertebrate retina on the basis of Werblin's results and other physiological results. The model is especially based on the following suggestions: The signal that acts to shift the bipolar curves is probably carried by horizontal cell processes extending from the surround to the center of the receptive field. Furthermore, amacrine cells carry a lateral antagonistic signal across the inner plexiform layer that affects the response properties of ganglion cells. The simulations of the model were made and the results of the ones considerably coincided with the experimental results of Werblin.