Itokazu Y, Käkelä R, Piironen J, Guan X L, Kiiskinen P, Vornanen M
Department of Biosciences, P.O. Box 65, FI-00014, University of Helsinki, Finland.
Department of Biosciences, P.O. Box 65, FI-00014, University of Helsinki, Finland.
Comp Biochem Physiol A Mol Integr Physiol. 2014 Jun;172:39-45. doi: 10.1016/j.cbpa.2014.01.020. Epub 2014 Feb 16.
Composition of membrane lipids from the gills of juvenile Atlantic salmon (Salmo salar) in presmolt and smolt phases of development was compared among anadromous and non-anadromous populations. Three stocks migrating from spawning rivers to either lake (landlocked stock), brackish water or full strength sea water were grown under common garden conditions, and gill lipids and their acyl and alkenyl chains were examined in February (presmolts) and at the end of May (smolts) by mass spectrometry and gas-liquid chromatography. The most remarkable changes upon transition from the presmolt phase to the smolt phase were: (i) increase in the cholesterol/phospholipid ratio, (ii) decrease in the abundance of phosphatidylinositol (PI) content, (iii) increase in the amount of sulfatides, (iv) increase in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species with two highly unsaturated acyl chains, and finally (v) convergence of interstock differences in PC and PE species composition towards a similar lipid composition. Increases in the gill membrane content of cholesterol and sulfatides are discussed as pre-adaptation of salmon gills for salt-secretion, which may occur by increases in membrane microdomains (rafts) harboring ion channels and pumps. The decreases of PI were likely related to adjusting the gill membrane permeability to ions by diminishing prostanoid production. The similarity of those changes among three salmon stocks and the convergence of initially (presmolt phase) different PC and PE species profiles between the stocks towards similar lipid composition suggests that smoltification process of the gill epithelium is largely similar in anadromous and landlocked populations.
在溯河洄游型和非溯河洄游型种群中，比较了处于幼鲑前期和洄游期发育阶段的大西洋鲑幼鱼鳃部膜脂的组成。将从产卵河流洄游至湖泊（陆封种群）、咸水或全强度海水的三个种群在共同园圃条件下养殖，并于2月（幼鲑前期）和5月底（洄游期）通过质谱分析和气液色谱法检测鳃脂及其酰基链和烯基链。从幼鲑前期到洄游期最显著的变化有：（i）胆固醇/磷脂比值增加；（ii）磷脂酰肌醇（PI）含量丰度降低；（iii）硫脂含量增加；（iv）具有两条高度不饱和酰基链的磷脂酰胆碱（PC）和磷脂酰乙醇胺（PE）种类增加；最后（v）PC和PE种类组成的种群间差异趋向于相似的脂质组成。鳃膜中胆固醇和硫脂含量的增加被认为是鲑鱼鳃为盐分分泌进行的预适应，这可能是通过含有离子通道和泵的膜微区（筏）增加实现的。PI的减少可能与通过减少前列腺素生成来调节鳃膜对离子的通透性有关。这三种鲑鱼种群间这些变化的相似性以及种群间最初（幼鲑前期）不同的PC和PE种类谱趋向于相似脂质组成，表明在溯河洄游型和陆封种群中，鳃上皮的洄游期变化过程在很大程度上是相似的。
