怒江裂腹鱼鳃的显微和超微结构

鳃为鱼类重要的呼吸器官，是鱼类进行离子交换、酸碱调节和含氮废物排泄的重要结构基础，也是鱼类重要的外周黏膜免疫器官之一，在抵御病原微生物侵染过程中发挥重要的免疫屏障作用。当前，硬骨鱼类鳃黏膜免疫反应是研究热点之一。本文首先对硬骨鱼类鳃的结构和特点进行分析，之后综述了抗菌肽、干扰素、白细胞介素、Toll样受体、补体等先天性免疫相关分子以及T细胞受体和免疫球蛋白等适应性免疫相关分子在硬骨鱼类鳃黏膜中的表达规律、分子功能，最后探讨了化学因素 (重金属、杀虫剂等)、生物因素 (细菌、病毒、真菌、和寄生虫等)以及营养物质和疫苗等对硬骨鱼类鳃黏膜结构的影响，以期为深入研究鳃在鱼类黏膜免疫反应中的角色和应答机制提供指导，为硬骨鱼类病原性疾病的免疫防控策略的制定提供理论基础。

Effects of dietary protein levels on the disease resistance,immune function and physical barrier function in the gill of grass carp (Ctenopharyngodon idella) after challenged with Flavobacterium columnare

Gill is not only an important respiratory organ of teleost, but also a structural foundation for ion exchange, acid-base regulation and nitrogenous waste excretion of fish. Importantly, it is one of peripheral mucosal immune organs of fish. The mucosal immune response of gill is the hot research topic. In this paper, we firstly analyzed the structure and features of gill. Then, we summarized the gene expressions and molecular functions of molecules involved in the innate immunity and adaptive immunity in gill. Antimicrobial peptides (AMPs), including NK-lysins, β-defensins, piscidins and hepcidins, are important innate immune molecules in fish gill, which can directly inhibit or kill a variety of pathogenic microorganisms. Fish type I interferon (IFN) and type II IFN in gill can be up-regulated by bacteria, viruses and parasites, indicating their important roles in gill immune response against pathogens. The interleukin (IL)-1, IL-2, IL-6, IL-10, IL-17 and heterodimer ILs are mainly expressed in gill, but possess distinct time-dependent patterns following pathogen invasion. Toll-like receptors (TLRs) are important pattern recognition receptors of fish. The TLR1-4, TLR7, TLR9, TLR12, TLR18, TLR21-22 are highly expressed in gill and up-regulated by pathogens. Fish possess similar complement molecules as mammals, and these complement molecules are highly expressed in gill and significantly up-regulated during pathogen invasion. T-cell receptors (TCRs) and immunoglobulins are the main adaptive immune molecules in gill. Similar to mammals, fish have four types of TCRs (TCRα, TCRβ, TCRγ and TCRδ). These four TCRs are induced by bacteria or parasites in gill. Three types of immunoglobulins (IgM, IgD, and IgZ/T) exist in gill. IgM and IgD in gill are involved in the recognition and binding of specific antigens, while IgZ/T is responsible for the mucosal immune response. Lastly, the effects of chemical factors (such as heavy metals, pesticides), biotic factor (such as bacteria, virus, parasites), nutriments, and vaccines on the structures of gill were analyzed. Heavy metals (such as copper, arsenic, mercury), pesticides, and pathogens invasion can destroy the normal structure of gills. Nutriments and vaccines have positive regulatory effects on the immune function of fish gill. This study may provide guidance for further study of the functional role and response mechanism of gill in fish mucosal immune response, and provide theoretical basis for the research and development of immune prevention and control strategies for pathogenic diseases of teleost.