大菱鲆Lily-型凝集素（SmLTL）晶体结构解析及抵御盾纤毛虫侵染机制研究

Ciliate disease is multiple diseases in the industrial aquaculture of turbot. Normal chemicals not only have difficulties in preventing its outbreak efficiently, but bringing serious problems, such as the safety of aquatic products and environmental pollution. Therefore, exploring a new kind of green and safe insecticidal substance is the urgent need for the healthy and continuous development of sea fish aquaculture. Lily type Lectin is a kind of mucous lectin that can be secreted by a mannose-binding fish itself, which can take part in fishes’ innate immune systems. Earlier works of this research group have firstly confirmed that Lily type lectin in turbot has the ability of inhibiting the activity of Philasterides dicentrarchi. However, there are barely reports about the insecticidal mechanism of this kind of lectin. Based on the earlier works, the drawn-up research analyzes SmLTL’s insecticidal specialty through its influence on shield ciliates’ microstructures; lunches SmLTL protein crystals’ structural measurement and model building to analyze the interaction mechanism between lectin and glycosyl; Makes use of yeast two-hybrid technique to screen shield ciliates’ bodies and SmLTL interacted glycoprotein to explore its protein interaction mode. All of these works are done to explain SmLTL insecticidal mechanism. This research will enrich molecular species of fish lectins and help to analyze the defense mechanism of mucous lectins, which can provide theoretical bases for researching its functions in innate immune systems.

盾纤毛虫病是大菱鲆工厂化养殖中多发性疾病，常规化学药物不仅难于有效遏制该病的暴发，还会带来水产品安全和环境污染等严重问题，故探寻绿色安全的新型杀虫物质是海水鱼类养殖业健康持续发展的迫切需求。Lily-型凝集素是一种与甘露糖结合的鱼体自身分泌的粘液凝集素，参与鱼类的先天免疫，本课题组前期工作已首次确认大菱鲆Lily-型凝集素(SmLTL)具有抑制盾纤毛虫活性的能力。但对于该类型凝集素抗虫机制研究却鲜有报道。拟申请课题在前期工作基础上，开展SmLTL对盾纤毛虫显微结构影响，分析其抗虫特性；开展SmLTL蛋白晶体结构测定与模型构建，解析凝集素与糖基相互作用机制；利用酵母双杂交技术，筛选盾纤毛虫体与SmLTL互作蛋白，探究其蛋白互作模式；等研究工作，阐述SmLTL抵御盾纤毛虫侵染机制。本研究将丰富鱼类凝集素的分子种类，有助于解析粘液凝集素的防御机制，为其在先天免疫系统中的功能研究提供理论依据。