アサクサノリの脂質成分におよぼす環境要因の影響

環境要因にともなう,アサクサノリの脂質の変動の様相を知る目的で,明・暗両条件下において,有機炭素源(主として,シュークローズ)を含有する培養海水と,炭素源として,炭酸ガスを供給する培養海水とで5日間培養したのち,藻体中の脂質をフロリジルカラムならびにシリカゲル薄層で分画し,それぞれの脂質量と,それらの脂肪酸組成を調べた.その結果,
1) 明条件下では,トリグリセライドとX成分(恐らく,グリコスフィンゴリピドと思われる)が増加し,その他の糖脂質と遊離脂肪酸の増加はみられなかった.有機炭素源を供給した暗条件下では,遊離脂肪酸が顕著に増加した.その他の脂質も,炭酸ガスを炭素源とする暗条件下のものより高い値を示した.
2) 脂肪酸組成の面では,すべての遊離脂肪酸画分中のリノレン酸の増加と,一部の脂質画分を除き,20:5酸の増加が目立った.20:1酸,および20:4酸も一部の脂質画分で増加することがみられた.

以上の結果から,アサクサノリは,シュークローズのような有機炭素源を,脂肪酸合成に利用し得ること,ならびに脂質代謝に関して,緑藻類のChlorellaとの相異点を有することなどが考察された.

In order to get a better knowledge of the effects of environmental factors on the lipid components, the fronds of laver, Porphyra sp., were cultured in the organic and inorganic media under light and dark conditions for five days. The extracted lipids were fractionated by means of Florisil column chromatography and Silica gel G thin-layer chromatography. The results can be summarized as follows.
1) Under light condition, it was observed that the triglycerides and the X components (possibly glycosphingolipids) increased, while the galactolipids, the sulfolipids and the free fatty acids did not. On the other hand the lipids of laver cultured in the organic medium under dark conditions contained a remarkable amounts of free fatty acids and larger amounts of other lipid components than those cultured by the inorganic medium.
2) In the fatty acids composition, the proportion of 20:1, 20:4 and 20:5 acids mainly changed in every condition.

From these results, it was concluded that the fronds of Porphyra sp. are able to utilize organic carbon sources such as sucrose. Moreover, phylogenetic differences on the lipid metabolism between red alga Porphyra and green alga Chlorella were discussed.