武陵洞蛭卵茧的形态结构和化学组成

Morphology and Chemical Composition of Sinospelaeobdella wulingensis Cocoons

摘要

卵茧是蛭类生活史中一个重要的阶段, 对卵茧进行研究具有重要的生态生物学意义。武陵洞蛭(Sinospelaeobdella wulingensis)是近年新发现的中国洞蛭属的模式种, 其在洞穴顶壁繁衍后代, 具有不同于水蛭和山蛭的生态生物学特征。鉴于武陵洞蛭的特殊性, 以及卵茧在洞蛭适应性进化过程中的关键作用, 本文对武陵洞蛭卵茧的形态结构和化学组成进行了初步研究, 结果显示: 1) 武陵洞蛭的卵茧大致呈椭球形, 长径(10.80±1.71) mm、短径(8.32±1.60) mm, 重量(135.3±76.8) mg; 2) 卵茧由外到内包括茧壁外层(蜂窝状)、茧壁内层、蛋白液和受精卵; 3) 茧内含有17种水解氨基酸和11种游离氨基酸, 其中谷氨酸和丙氨酸分别在水解氨基酸和游离氨基酸中的相对含量最高; 4) 在卵茧中共鉴定出68种可信蛋白质, 其中27种为未鉴定蛋白质, 其余41种可信蛋白质主要分为6类, 即抗氧化蛋白5种、酶蛋白12种、细胞骨架蛋白6种、结合蛋白12种、热休克蛋白2种、其他蛋白质4种。以上卵茧的形态结构和化学组成是洞蛭对洞穴生态环境长期适应的结果, 卵茧对洞蛭物种进化和种群存续的关键作用值得深入系统的研究。

Abstract

Cocoons are a key life-history stage of leeches, so it is of great ecobiological significance to clarify their morphological features and chemical composition. Wuling cave leeches (Sinospelaeobdella wulingensis) are the type species of the newly-described genus Sinospelaeobdella, which breed on the roof wall of karstic caves, and differ from water and land leeches ecobiologically. In view of the particularity of Wuling cave leeches and the key role of cocoons in the adaptive evolution of leeches, morphology and chemical composi-tion of the cocoons were preliminarily studied. The results showed that: 1) Cocoons of Wuling cave leeches were roughly ellipsoidal, with a long diameter of (10.80±1.71) mm and a short one of (8.32±1.60) mm, and a weight of (135.3±76.8) mg; 2) From outside to inside, each cocoon had the outer layer (honeycomb) and in-ner layer of cocoon-wall, protein fluid and fertilized egg; 3) There were 17 kinds of hydrolyzed amino acids and 11 kinds of free amino acids in the cocoon, among which the relative contents of glutamic acid and ala-nine were the highest; 4) There were 68 kinds of trusted proteins identified in the cocoon, of which 27 were unidentified, and the remaining 41 could be divided into 6 categories, namely 5 antioxidant proteins, 12 en-zyme proteins, 6 cytoskeletal proteins, 12 binding proteins, 2 heat shock proteins and 4 other proteins. The morphological characteristics and chemical composition of the cocoons reflect long-term adaptation of leeches to cave ecological environments. The crucial role of the cocoon in the species evolution and population sur-vival of the leeches deserves further systematic investigation.

关键词

武陵洞蛭 / 卵茧 / 形态结构 / 化学组成

Key words

Sinospelaeobdella wulingensis / cocoon / morphology / chemical composition