Highly efficient oligosaccharide synthesis on water-soluble polymeric primers by recombinant glycosyltransferases immobilised on solid supports

Recombinant beta-1,4-galactosyltranferase (beta 1,4-GalT) and alpha-2,6-sialytransferase (alpha 2,6-SiaT) immobilised covalently with activated Sepharose beads were employed for the practical synthesis of a trisaccharide derivative, Neu-5Ac alpha(2-->6)Gal beta(1-->4)GlcNAc beta-O-(CH2)6-NH2, on a water-soluble primer having GlcNAc residues through a alpha-chymotrypsin-sensitive linker.     

Perceptual discrimination of very high frequency components in wide frequency range musical sound

Subjective evaluation tests on perceptual discrimination between musical sounds with and without very high frequency (above 20 kHz) components were conducted. To make a precise evaluation, the test system was designed to exclude any influence from very high frequency components in the audible frequency range. Moreover, a newly developed very wide frequency range microphone was used to record various sound stimuli that contained enough components in the very high frequency range. Tests showed that the subjects could discriminate between musical sounds with and without very high frequency components. This paper describes these subjective evaluations in terms of reproducing such very high frequency components in musical sound.     

From C-glycosides to pyranopyrans: an approach to thyrsiferol using titanium(III)-promoted redox couplings

An approach to the pyranopyran ring system that is found in many natural products, including thyrsiferol, is described. The route entails the assembly of an alpha,beta-unsaturated ketone (11) from geraniol and dihydropyran (23) from acetyl acetaldehyde dimethyl acetal (19) and their titanium(III)-promoted coupling to afford a respectable 60% yield of keto alcohol 26. The sigma-bond formed in this process corresponds to the pro-C(9)-C(10) bond of thyrsiferol (4). Attempts to invert the stereochemistry at the pro-C(11) center were thwarted by the congestion imparted by the presence of the vicinal TBS-ether. Consequently, cyclization of the coupling adduct under conditions developed by Olah and Prakash and co-workers led to the cis-fused pyranopyran 27. X-ray analysis of this crystalline material confirmed each of the stereochemical assignments. After much effort, it was determined that the hydroxyl group at C(12) could be removed by treating the derived methyl xanthate with a tri-n-butylphosphine-borane complex under radical-forming conditions. The reaction sequence worked well, despite the hindered working environment and the presence of a potentially labile C-Br bond.     

Phytogrowth-inhibitory and antimicrobial activities of 3,4'-dihydroxy-alpha,beta-diethylstilbene, the isomer of diethylstilbestrol

3,4'-Dihydroxy-alpha,beta-diethylstilbene (I), like diethylstilbestrol (II), showed phytogrowth-inhibitory and antimicrobial activities. First, compound I showed strong growth-inhibitory activity against the roots of two kinds of plants. The inhibitory activity of I was almost equal to that of sodium 2,4-dichlorophenoxyacetate used as a positive control. The phytogrowth-inhibitory activity of I was much higher than that of II. Next, unlike II, I had broad antifungal spectrum against phathogenic fungi. Compound I showed antifungal activity against six kinds of Fusarium oxysporum sp. This compound also had antibacterial activity against pathogenic and plant-pathogenic bacteria. These antibacterial activities of I were as high as those of II, the isomer of I. It should be emphasized that by shifting one of the phenolic hydroxyl groups of II to meta-position, phytogrowth-inhibitory activity was largely increased, while antimicrobial activity was unchanged.     

Improved Swelling Property of Tissue Adhesive Hydrogels Based on α-Cyclodextrin/Decyl Group-Modified Alaska Pollock Gelatin Inclusion Complexes

Adhesives/sealants are used after suturing to prevent leakage of cerebrospinal fluid from an anastomotic site. Commercial adhesives/sealants have been used to close the cerebral dura. However, swelling of the cured adhesives/sealants induces increased intracranial pressure and decreases the strength of the seal. In the present study, tissue adhesive hydrogels with improved swelling property using inclusion complex composed of α-cyclodextrin (αCD) and decyl group (C10)-modified Alaska pollock-derived gelatin (C10-ApGltn) with a high degree of substitution (DS) (>20 mol%) are developed. Viscosity of C10-ApGltn with a high DS solution remarkably decreased by the addition of αCD. The resulting αCD/C10-ApGltn adhesive hydrogel composed of αCD/C10-ApGltn inclusion complexes and poly(ethylene glycol) (PEG)-based crosslinker showed improved swelling property after immersion in saline. Also, the resulting adhesive has a significantly higher burst strength than fibrin-based adhesives and is as strong as a PEG-based adhesive. Quantitative analysis of αCD revealed that the improved swelling property of the resulting adhesive hydrogels is induced by the release of αCD from cured adhesive, and the subsequent assembly of decyl groups in the saline. These results suggest that adhesives developed using the αCD/C10-ApGltn inclusion complex can be useful for closing the cerebral dura mater.     

A facile method for generation of carbon oxide sulfide

Carbon oxide sulfide was easily generated upon heating of amine salts of carbamothioic acids at 85°C which were produced in situ from amines, carbon monoxide, and elemental sulfur in the presence of a catalytic amount of selenium under mild conditions.