Lipid composition for freeze-tolerance at different seasons and altitudes in the earthworms
|Keywords:||蚯蚓;飽和脂肪酸;不飽和脂肪酸;脂肪酸組成;抗寒生理;earthworm;saturated fatty acids;unsaturated fatty acids;lipid composition;freeze-tolerance||Issue Date:||2015||Abstract:||
本研究的主要目的在於探討蚯蚓體內的脂肪酸組成是否會改變以因應環境溫度的變化。由於已知細胞膜不飽和脂肪酸特別是EPA (Eicosapentaenoic acid)及DHA (Docosahexaenoic acid)比例越高，細胞越不容易被冰凍所傷害個體的抗寒能力也越強，因此本研究擬藉由測量蚯蚓的脂肪酸組成來探討其抗寒能力，並且評估外來種黃頸蜷蚓(Pontoscolex corethrurus)未來是否可能入侵到較高海拔的環境。實驗方法是在不同季節的高海拔及中海拔採集棋盤遠環蚓(Amynthas tessellatus tessellatus)，帶回實驗室分析其脂肪酸的組成。另將平地黃頸蜷蚓帶回實驗室以不同溫度飼養後分析其脂肪酸的組成。結果顯示合歡山棋盤遠環蚓在低溫時不飽和脂肪酸比例較高，相對的飽和脂肪酸較低且高海拔蚯蚓的DHA較中低海拔蚯蚓高，冬季時DHA較夏季時高，但黃頸蜷蚓蜷無此現象。再者黃頸蜷蚓的總脂肪酸組成比例並不會因飼養於低溫而有顯著差異，因此黃頸蜷蚓可能無法在短期內調節脂肪酸組成來適應低溫環境，由此推測黃頸蜷蚓在台灣要擴散到高海拔地區是有困難的。
The aim of my research is to understand the relationship between the composition changes of cellular lipids in earthworms and their cold resistance. It has been well known that the lipid bilayer membrane with more unsaturated fatty acid including EPA (Eicosapentaenoic acid) & DHA (Docosahexaenoic acid) can resist lower temperature damage. Therefore the fatty acid composition of cell membrane is a suitable index to evaluate the ability of cold resistancen in animals. To find out whether does the earthworm’s cellular lipids compositions change in low temperature, earthworms were collocated from different seasons and different altitudes, or were kept and acclimated at different temperatures. The results showed that Amynthas tessellatus tessellatus has higher proportion of unsaturated fatty acids and lower the proportion of saturated fatty acids at low temperature. Especialy, the amount of DHA in A. tessellatus tessellatus from high altitude was higher than that from media altitude. Also, the amount of DHA in those earthworms collected from winter time was higher than that from summer time. The total fatty acid composition in Pontoscolex corethrurus had no significant difference under different temperature acclimatuon. Because Pontoscolex corethrurus does not have physiological mechanism to regulate their fatty acid composition during temperature changing situation. It might infer that Pontoscolex corethrurus should be difficult to spread to higher altitude areas in Taiwan.
|Appears in Collections:||生命科學系|
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