Makio Asakawa

Stereoselective reduction of 4-benzoylpyridine by recombinant pig heart carbonyl reductase

Abstract Optically active (−)- and (+)-α-phenyl-4-pyridylmethanol [(−)- and (+)-PPOL] were synthesized from 4-benzoylpyridine (4-BP) and established to possess (S)- and (R)-configurations, respectively, by X-ray single crystal structure analysis. When 4-BP was incubated in the reaction mixture containing recombinant pig heart carbonyl reductase (rPHCR) and NADPH, the reduction product appeared as a main peak corresponding to (S)-(−)-PPOL on high-performance liquid chromatography (HPLC). This result indicates that rPHCR has the ability to reduce stereoselectively 4-BP to (S)-(−)-PPOL with high optical purity.

PURIFICATION AND IDENTIFICATION OF N-GLYCOLYLNEURAMINIC ACID (Neu5Gc) FROM THE HOLOTHUROIDEA GUMI, CUCUMARIA ECHINATA

N-Glycolylneuraminic acid (Neu5Gc), precious sialic acid which could not be synthesized by a chemical method, occurrs in the body of holothuroidea, Gumi Cucumaria echinata. Gumi contains 85% of total sialic acid, as Neu5Gc, in the body. Neu5Gc was purified from dry powder of the body using Dowex 1-x8 (HCOO− form) anion exchange chromatography after mild acid hydrolysis with 0.1 N trifluoroacetic acid. Using GC-MS and 1H-NMR spectroscopy, the purified Neu5Gc was correctly identified to be Neu5Gc. The purity of Neu5Gc was more than 99%. This is the first report of purification and identification of Neu5Gc from holothuroidea by using anion exchange chromatography, GC-MS, and 1H-NMR.

Structural characterization of the trisaccharide chain from the skin mucus glycoprotein of the rainbow trout, Salmo gairdneri

Skin mucus glycoprotein (RGP) was extracted from the skin mucus of rainbow trout, Salmo gairdneri. Alkaline borohydride treatment of RGP yielded a major oligosaccharide alditol NeuAcα2 to6GalNAc-ol and several minor oligosaccharide alditols. A trisaccharide alditol (OS-I) was purified by Sephadex G-25 gel filtration and high-performance liquid chromatography (HPLC). The amount of OS-I was estimated to be 7% in RGP from the amount of GalNAc-ol. Structural determination of the OS-I was examined. Structure of OS-I was identified to be NeuAcα2 to6 (GalNAcα1 to3) GalNAc-ol by α-N-acetylgalactosaminidase digestion, methylation analysis, and 1H-NMR spectroscopy.

Elastin peptide receptor-directed monocyte chemotactic polysaccharides derived from seaweed sporophyll and from infectious fungus

We discovered that a seaweed sporophyll-derived polysaccharide of brown alga, Wakame (Undaria pinnatifida) bound to monocytes and attracted them in vitro and in vivo. Physicochemical properties, affinity to a lectin-bead column and sugar composition of the chemotactic polysaccharide indicated this molecule to be a highly sulfated fucogalactan. We then identified the monocyte receptor of the sulfated fucogalactan as the elastin peptide receptor by prophylactic inhibition of the binding and the chemoattraction with lactose and the synthetic elastin peptide, Val-Gly-Val-Ala-Pro-Gly. We assume that the galactose-binding lectin, which is a component of the elastin peptide receptor complex, would recognize a Gal residue of the sulfated fucogalactan. We also observed a similar chemoattracting polysaccharide in a pathogenic fungus, Candida albicans, although the content of it was much lower than in the case of seaweed sporophyll. We speculate that the chemotactic response of monocytes to the sulfated fucogalactan is part of the innate immune system to fungal infection.

Shock Sterilization of Dry Powder Foods

The sterilization for fungi and bacteria in some kinds of dry powder foods is limited to keep their grade. Especially in spices the heat sterilization is restricted to minimum use, because the heat reduces the hot-taste that is a principal component in spices. The operation for the sterilization has to act only on fungi and bacteria, not to degrade the volatile components contained in flavor elements. In this paper, the instance of shock sterilization is shown, and the development of the idea to the sterilization equipment and its performance are presented. Experimental results showed the potential of the shock for the sterilization and the feasibility for the industrial use.Copyright

Cell ruptures of microorganisms by shock wave and ultrasonic wave

A sterilization and a cell rupture using the shock wave generated by a wire explosion was tested and the effect of the impulsive load on the mortality of microorganism. This technique enables the sterilization of foods, juice or chemical agents without heating them. Microorganism cells were broken by shock waves and ultrasonic waves and different fracture patterns were shown in the SEM image. In the shock the efficiency was depended on the size of bacteria, although that was depended on the strength of the cell membrane in the ultrasonic. It was also found that the shock is effective for spores of bacteria that are superior to normal cells in the endurance and the resistibility. Numerical simulations demonstrated the size effect in the shock cell rupture.Copyright