Yasuhiko Fujino

Sphingolipids in Immature and Mature Soybeans

Ceramides and cerebrosides were isolated from immature and mature soybeans, and structures of the constituents were investigated. As component fatty acids, normal, 2-hydroxy and 2,3-dihydroxy acids were found in ceramides, whereas only normal and 2-hydroxy acids were identified in cerebrosides. The principal fatty acid component was 2-hydroxylignoceric acid in ceramides, and 2-hydroxypalmitic acid in cerebrosides. Sphingoids in ceramides consisted mainly of trihydroxy bases, with 4-hydroxy-trans-8-sphingenine being predominant. In contrast, cerebrosides contained mainly dihydroxy bases, the principal constituent beingtrans-4,trans-8-sphingadienine. The only sugar in cerebrosides was glucose. The constituents of the two sphingolipids were similar to each other in immature and mature seeds. Possible metabolic relations of plant sphingolipids, based on composition, are discussed.

Sphingolipids in wheat grain

Ceramide, mono-, di-, tri- and tetraglycosylceramides were isolated from wheat grain and the structures were studied. Ceramide consisted mainly of hydroxy fatty acid amides of trihydroxy bases, and the principal species was characterized as N -2′-hydroxy-tetracosanoyl-4-hydroxysphinganine. The fundamental glycosidic structures of the glycosylceramides were Glc(1 → 1)-ceramide, Man(1 → 4)-Glc(1 → 1)-ceramide, Man(1 → 4)-Man(1 → 4)-Glc(1 → 1)-ceramide and Man(1 → 4)-Man(1 → 4)-Man(1 → 4)-Glc(1 → 1)-ceramide, respectively. Experimental evidence suggested that all the glycosidic linkages had the β configuration. This is the first time that the structure of tetraglycosyl sphingolipid has been established in higher plants. The ceramide portions of these glycolipids were different from those in the free ceramide; the principal fatty acids in the glycolipids were hydroxypalmitic and hydroxyarachidic acids; the major sphingoid was cis -8-sphingenine.

Characterization of acylmono-, mono-, di-, tri- and tetraglycosylsterol and saponin in Adzuki bean (Vigna angularis) seeds

Five sterylglycosides (acylmono-, mono-, di tri- and tetraglycosylsterol) and a saponin were isolated from Adzuki beans and characterized. In the glycosylsterols, the principal component sterols were sitosterol and stigmasterol; the major sugar component was glucose. The glucose units were shown to be linked by β1,6-bonds. The three oligoglycosylsterols were shown to be gentiobiosylsterol, gentiotriosylsterol and gentiotetraosylsterol; the latter two are novel sterylglycosides. The saponin was identified as glucopyranosyl-(β1→2)-glucopyranurosyl-(β1→3′)-soyasapogenol B (Azukisaponin I) which had previously been found in Adzuki beans.

Further studies on sphingolipids in wheat grain

The principal molecular species of sphingolipids in wheat grain were confirmed to beN-2′-hydroxylignoceroyl-4-hydroxysphinganine for ceramide, and 1-O-β-glucosyl-, 1-O-[β-mannosyl(1→4)-O-β-glucosyl]-, 1-O-[β-mannosyl(1→4)-O-β-mannosyl(1→4)-O-β-glucosyl]-and 1-O[β-mannosyl(1→4)-O-β-mannosyl(1→4)-O-β-mannosyl(1→4)-O-β-glucosyl]-N-2′-hydroxypalmitoyl (or hydroxyarachidoyl)-cis-8-sphingenine for mono-, di-, tri- and tetraglycosylceramide, respectively. A novel glycolipid, cellobiosylceramide, was found as the minor diglycosylceramide; the major species was characterized to be 1-O-[β-glucosyl(1→4)-O-β-glucosyl]-N-2′-hydroxypalmitoyl (or hydroxyarachidoyl)-cis-8-sphingenine. It was observed in these sphingolipids that the dihydroxy bases were combined mainly with C16 and C20 acids, whereas the trihydroxy bases combined mostly with acids of chain length of 20 or more.

Characterization and composition of sterols in the free and esterified sterol fractions ofAspergillus oryzae

Free and esterified sterol fractions were isolated fromAspergillus oryzae, and their components analyzed mainly by gas chromatography-mass spectrometry. Cholesterol, brassicasterol, episterol (5α-ergosta-7,24[28]-dien-3β-ol), 4α-methyl-5α-ergosta-8[9],24[28]-dien-3β-ol, lanosterol and 24-methylene-24-dihydrolanosterol were well characterized, whereas 5-dihydroergosterol, sitosterol and 24[28]-dehydroergosterol were tentatively characterized. The principal sterol of the free sterol fraction was brassicasterol, and that of the esterified sterol fraction was episterol. Ergosterol, which is reported to be widely distributed in the fungi kingdom, was not detected.

Mono- and triglycosylsterols from the leafy stem of rice

Abstract Two sterylglycosides have been isolated from rice plants and identified as β- d -glucopyranosyl (1 → 3)-sitosterol and β- d -glucopyranosyl(1

Enzymatic formation of hexadecenoic acid from palmitic acid.

Desaturation of palmitic acid was investigated in an enzyme system prepared from rat liver. 2-trans-Hexadecenoic acid as well as 9-cis-hexadecenoic acid (palmitoleic acid) were found to be formed as monoenoic acid in this system.

Steryl Glycoside in Alfalfa Leaves

Steryl glycoside was isolated and purified from alfalfa leaves to be analyzed for constituent sterol and sugar. The major component sterols were β-sitosterol as well as stigmasterol and the component sugar was only glucose, suggesting that the typical molecular species of steryl glycoside in alfalfa leaves are β-sitosteryl glucoside and stigmasteryl glucoside.

Studies on the lipids of egg yolk

卵黄の脂質から主としてケイ酸カラムクロマトグラフィーによりセレブロシドを純粋に単離した.これを加水分解して,構成する脂肪酸,スフィンゴシン塩基および糖を調べた.構成脂肪酸は15種見出され,そのうちほぼ58%がオキシ酸,42%が直鎖酸であった.オキシ酸としては,オキシリグノセリン酸(22.0%),オキシベヘン酸(19.3%)およびオキシトリコサン酸(12.2%),直鎖酸としてはリグノセリン酸(15.7%),パルミチン酸(9.6%),べヘン酸(7.2%)などが主なものであった.構成長鎖塩基としては,スフィンゴシンとジヒドロスフィンゴシンが見出され,前者が大部分(84.5%)を占めていた.構成糖としては,グルコースとガラクトースがほぼ1:1の割合で含まれていた.これと対応して,卵黄セレブロシドは,グルコシルセラミドとガラクトシルセラミドのほぼ等量ずつから成ることが認められた.

Glycolipids of bovine milk

1. 牛乳の代表的な糖脂質として,セラミドモノヘキソシドとセラミドジヘキソシドを単離し,それぞれの構成分を調べた.2. 脂肪酸については両者の間に差がなく,どちらもC23:0, C24:0, C22:0およびC16:0の脂肪酸が主成分であった.3. 構成糖としては,セラミドモノヘキソシドにグルコース1分子,セラミドジヘキソシドにグルコースとガラクドース各1分子が含まれていた.4. スフィンゴシン塩基としては,CMHもCDHもともにC16-スフィンゴシン,C16-ジヒドロスフィンゴシン,C17-スフィンゴシン,16-メチル-C17-スフィンゴシン,C18-スフィンゴシンおよびC18-ジヒドロスフィンゴシンを含み,そのなかでC18-スフィンゴシンの量第がもっとも多かった.