Ryuichiro Tanaka

Isolation and characterization of a novel type of glycosphingolipid from Neanthes diversicolor

Abstract Five glycosphingolipids were obtained in the pure state from the marine annelid, Neanthes diversicolor. Final isolation of the individual compound was achieved by means of preparative HPLC with a reversed phase column in a recycling mode. They were assigned the structures, 1-O-β- d -6-O-[2′-( trimethylammonio )- ethylphosphoryl ] galactopyranosyl , -N-hexadecanoyl-(4E,8E)-sphingadiene (1), -N-hexadecanoyl-(4E)-sphingenine (2), -N-heptadecanoyl-(4E)-sphingenine (3), -N-octadecanoyl-(4E)-sphingenine (4) and -N-hexadecanoyl-sphinganine (5). It is noted that they are the monogalactosyl ceramides carrying the phosphocholine group in the galactose moiety, and that one of them contains an odd numbered fatty acid residue.

New Polar Constituents of the Pupae of the Silkworm Bombyx mori L. I. Isolation and Identification of Methionine Sulfoxide, Methionine Sulfone, and γ-Cyclic di-L-Glutamate

In addition to serine (L:D = 68:32), methionine sulfoxide (MSO), L-methionine sulfone (L-MSO2), and disodium γ-cyclic di-L-glutamate were identified in a methanol extract of Bombyx mori L. pupae. MSO was isolated in a diastereomeric mixture of L(+)- and D(+)-MSO in a ratio of 99:1. The presence of these compounds in other developmental stages, including eggs, larvae (1st, 4th, 5th, and mature 5th instar), adults, and excrement (feces and urine) was investigated. The L(+)-isomer of MSO was present in extracts of the 1st and 5th instar larvae, adults, and eggs, but was not detected in feces or urine. The D(+)-isomer was found only in pupal stage extracts, and was excreted into the meconium with L(+)-isomer. L-MSO2 and γ-cyclic di-L-glutamate were not detected at other insect life stages or in the insect excrement. γ-Cyclic di-L-glutamate is thought be produced due to blockage of the glutamate synthetic pathway (glutamine synthetase) by L-MSO2 and Mg2+. The biochemical role of L-MSO2 during the pupal life stage remains unknown, but importantly, the stage-specific expression suggests that it is a candidate molecule for the induction of diapause.

New Polar Constituents in the Pupae of the Silkworm Bombyx mori L. (II): Developmental Changes of the Constituents

A correlation between the quantitative changes in L-methionine analogs, the ratio of D-serine/L-serine during the pupal stage, and metamorphosis was observed. The glycoside appearing at low blood sugar values during the pupal stage was isolated and characterized as D-glucosyl-L-tyrosine. 1H-NMR indicated the appearance and increase of this glycoside, and Mirrorcle Ray CV4 equipment was used to take X-ray pictures of the pupal bodies. The results indicate that γ-cyclic di-L-glutamate and L-methionine sulfone might be concerned with ammonia assimilation in the pupae, and that D-glucosyl-L-tyrosine served as a switch for the fatty acid (pupal oil) dissimilation hybrid system.

Evidence for the presence of 1,2-cyclic acetal type sn-glycero-3-phosphoethanolamines in the sea anemone, Actiniogeton sp.

Five 1,2-cyclic acetal-type sn-glycero-3-phosphoethanolamines (CGPE) were isolated in a pure state from the sea anemone, Actiniogeton sp. (Coelenterata). Their structures, including the absolute configurations, have been determined on the basis of chemical and spectral data to be so-called Feulgens acetalphosphatides, which have been regarded as artifacts derived from original plasmalogens. We examined whether these CGPE are intact constitutents in the animal tissues and obtained reliable confirmation that CGPE are normally present in the sea anemone.

Cyclic Dipeptide of D -Ornithine Obtained from the Dobsonfly, Protohermes grandis Thunberg

A new compound was isolated from the water-soluble fraction of a methyl alcohol extract obtained from the larva of the dobsonfly (Protohermes grandis Thunberg). The novel compound had a 12-membered ring and was confirmed to be a cyclic dipeptide of D-ornithine by a chiral analysis, using high-performance liquid chromatography, 2D-nuclear magnetic resonance, and field desorption mass spectrometry.