Yutaka Ishigami

Surface active properties of biosoap from spiculisporic acid

Abstract Penicillium spiculisporum produces 4,5-dicarboxy-4-pentadecanolide (spiculisporic acid, S-acid) efficiently from glucose. Three kinds of sodium salts of S-acid were prepared. As a result of potentiometric titration, IR, and 13C NMR, it was concluded that the monosodium salt of S-acid (S-1Na) consisted mainly of the neutralizing product of the carboxylic group attached to the 4-positioned carbon of S-acid, the disodium salt of S-acid (S-2Na) corresponded to the neutralizing product of the carboxylic group attached to the 4- and 5-positioned carbons, and the trisodium salt of S-acid (S-3Na) was the saponified product of the lactone group of S-2Na. The micelle formation of these three kinds of S-acid salts was ascertained in water by means of both surface tension and electrical conductance measurements. And, the CMC values were S-1Na, 3.9 × 10−3; S-2Na, 6.1 × 10−2; and S-3Na, 1.7 × 10−1 mole/liter, respectively. These three salts showed low foaming properties, with S-2Na having the highest foaming property of the three. Further, these showed a dispersing action for hydrophilic pigments, as well as showing both calcium ion sequestration and buffering actions. It will be a future theme to study the connection with the biological function of S-acid from the viewpoint of biosurfactant.

Glycosylation reaction under high pressure

Abstract Glycosylation of various alcohols with 2,3,4,6-tetra- O -benzyl-α-D-glucopyranosyl bromide ( 1 ) in the presence of hindered amines under conditions of high pressure gave α-glycosides in good yield with high selectivity.

Electrical control of reversible microgel flocculation and its estimated performance as a display device

Abstract Reversible flocculation of pH-responsive microgels with poly-L-lysine was electrically controlled by a pH modulator. The pH modulator was composed of a polypyrrole-coated Pt electrode coupled with an Ag/AgCl counter-electrode. The applicability of the flocculation system for display devices was examined to determine whether its performance was comparable with that of conventional display devices. A display performance of contrast 50 in 50 ms with operating potentials of ±0.4 V will be attained in a proposed cell where vertical microelectrode arrays are built in.

Penetration enhancement across a model membrane by liposomally entrapped drugs using N,N′‐diacylcystine as a bilayer lipid

A liposomal system for percutaneous absorption and transdermal drug delivery was developed and evaluated using a model apparatus connecting two chambers by a membrane. When N,N′‐long chain diacyl L‐cystine was incorporated into the liposomal bilayer as well lecithin and cholesterol, liposomally entrapped calccin as the model drug transferred well across the keratin membrane functioning as the skin model.

Synthesis and Properties of Rhodamine-type Dyes Derived from Spiculisporic Acid

A new rhodamine-type fluorescent dye having a functional long alkyl moiety (xanthene dye) was synthesized and their properties were investigated. The anhydride of spiculisporic acid which was produced in the culture broth of Penicillium spiculisporum was reacted with m-diethylaminophenol to give rhodamine-type dyes. Aqueous solutions of the dye in the acidic conditions showed wine color Amax 571 nm, Fluorescence 2max 589 nm, differently from brilliant red colors in the conventional rhodamine dyes. Furthermore, hydrochloric acid salt of the dye was surface active (35.1 mN/m at rcmc) and formed micelles in water.