鳜骨骼肌快肌和慢肌的组成特征比较

骨骼肌组成特征是鱼类肉质性状评价的重要基础。为全面了解鳜（Siniperca chuatsi）肉质性状的组成特征，通过制作骨骼肌石蜡切片，比较了鳜快肌和慢肌两种类型骨骼肌的组织学特征，快肌和慢肌在肌纤维细胞直径、形态上存在差异。利用SDS聚丙烯酰胺凝胶电泳（SDS-PAGE）分析了鳜快肌和慢肌的蛋白质组成特征，它们在50～60 ku和10～15 ku大小的条带中存在差异。克隆了鳜快肌和慢肌肌球蛋白重链（MHC）S1结构域的序列，快肌和慢肌S1结构域cDNA序列长度分别为2 523 bp、2 520 bp，编码841、840个氨基酸，氨基酸序列的相似度为87.6%，以两个loop区的差异最大。研究结果表明，鳜快肌、慢肌在肌纤维细胞形态、蛋白质组成以及肌球蛋白重链分子结构上均存在较明显的差异，这些差异与其担负不同的运动功能相关。

Comparison on characterization of fast twitch and slow twitch skeletal muscles of mandarin fish Siniperca chuatsi

Muscle fibers and their molecular composition are the important base for evaluation on fish meat quality. To fully understand the characterization of fast twitch and slow twitch muscles of mandarin fish Siniperca chuatsi, histological characters of two different skeletal muscles (fast twitch and slow twitch muscles) were analyzed by paraffin sections, and these two muscle fibres had different shapes and diameters. Protein compositions of fast muscle and slow muscle were compared according to the number of protein bands and their mobility separated by polyacrylamide gel electrophoresis (SDS-PAGE), and some specific bands existed in 50-60 ku and 10-15 ku. The subfragment 1(S1) cDNA of the fast and slow muscle moysin heavy chain were cloned and sequenced by PCR method, the S1 sequences of fast and slow muscle were 2 523 bp and 2 520 bp, which encoded 841and 840 amino acids, respective. They shared 87.6% identities in amino acid sequence, of which loop-1 and loop-2 regions were highly variable. These results showed that fast muscle and slow muscle had significant differences at histological, protein composition and molecular levels, which suggested their different motion functions.