鱼类抗菌肽的研究进展

抗菌肽是一类广泛存在于生物界的小分子短肽,具有广谱的抗菌、抗病毒、抗寄生虫及抗癌等生物活性。它是鱼类自身先天免疫系统的重要组成部分,结构复杂,种类多样。本文综述了目前发现的鱼类抗菌肽的结构特点、种类、生物学功能、抗菌机制以及基因工程上的研究进展。     

鱼源抗菌肽研究进展

<正>抗菌肽是生物体内的小分子多肽,是构成生物体先天免疫系统的重要成分。抗菌肽具有广谱抗菌及抗病毒等特性,细菌对抗菌肽比传统抗生素更难产生抗性,是传统抗生素的理想替代品。目前已从各种生物中分离出了逾2000种抗菌肽[1-3]。鱼类种类繁多,生境复杂,是抗菌肽的重要来源,目前已报道了150余种鱼源抗菌肽[4]。鱼源抗菌肽不仅具有抗菌肽的共有特征,如广谱抗菌性能、免疫调控性能,还有一些种类特异性,以利于鱼类应对复     

抗菌肽与鱼类肠道健康研究进展

我国是水产养殖大国,随着高密度、集约化养殖模式的发展,养殖中各种病害频繁发生,大量甚至提前使用抗生素进行病害预防相当普遍,抗生素的残留及耐药性对我国水产养殖业造成了严重影响。在纷纷寻求抗生素替代物的背景下,抗菌肽具有广谱抗菌性,较抗生素而言具有独特的抗菌机理,养殖过程中使用抗菌肽不易产生耐药性菌株,又具有提高鱼类等水生动物的生产性能及非特异性免疫功能等作用,正逐渐成为替代抗生素的新型抗菌药物而用于水产养殖中。目前有关抗菌肽在水产养殖上的应用研究主要集中在鱼类等水生动物自身产生的抗菌肽以及作为饲料添加剂的外源性抗菌肽。外源抗菌肽经摄食途径进入肠道,改善鱼类肠道的肠绒毛、肠皱襞高度及肌层厚层等组织形态结构,促进消化吸收功能;调节肠道菌群结构,在杀灭肠道有害微生物的同时增加益生菌含量,改善肠道微环境;在提高肠道消化酶活性和抗氧化能力等方面保障鱼类的肠道健康,同时提高鱼类生产性能、改善其品质、增强鱼体抗氧化和免疫功能[1-3]。笔者着重从水产养殖中抗菌肽饲料添加剂的来源及其与肠道菌群、肠道组织结构、肠道消化功能等相关研究进行总结分析,探讨存在的问题和对策,为抗菌肽在水产养殖中的应用,特别是保护鱼类肠道健康提供参考。     

鱼类抗菌肽研究进展（一）

<正>抗菌肽是一类广泛存在于自然界中的高度保守的多肽,在体外和体内都表现出广谱抗菌活性。抗菌肽最早在两栖动物中发现,随后在兔和人类中发现~([1])。鱼类中发现的最早的抗菌肽是1980年从美洲鲽中发现的,但直到1996年后才有突破性的进展,目前鱼类抗菌肽研究已取得与其他脊椎动物物种相同的进展,发现了piscidin家族(鱼类特有的抗     

鱼类铁调素（Hepcidin）的研究进展

铁调素是一类具有调节铁代谢功能的抗菌肽,在鱼类中广泛存在。文章介绍了Hepcidin的基本结构、生理功能,并总结了鱼类Hepcidin基因的克隆和表达、抗菌活性、铁代谢活性的研究进展,以期为鱼类Hepcidin的开发和利用奠定一定的基础。     

中华倒刺鲃血清凝集素对细菌凝集作用的观察报告

随着水产养殖业的繁荣,水污染加剧,养殖鱼类频频发生各种疾病,因此研究鱼类抗菌相关的特别是非特异性免疫因子,已成为世界研究热点。目前研究的鱼类抗菌相关因子主要包括:凝集素、抗菌肽、干扰素、补体、白细胞介素、溶菌酶、转铁蛋白、鱼精蛋白、金属硫蛋白、免疫球蛋白等等。     

再谈抗菌肽及其在水产养殖上的应用(上)

正随着我国水产养殖业快速发展,各种疾病频频发生,抗生素大量使用甚至滥用的情况也日趋严重,寻找抗生素的替代物已迫在眉睫。而抗菌肽作为一种新型的高效抗菌药物,由于其具有分子量小、水溶性好、抗菌谱广且作用机制特别、不易产生耐药性等优点,成为新型抗生素开发的良好候选资源。鱼类抗菌肽的研究不仅加深了人     

水产动物抗菌肽在水产养殖中的应用前景

抗菌肽fAntibacterial peptide）又叫抗微生物肽（AntimicrobialpepIide）、抗生素肽（Antihioticsppetide），是生物体内产生的一类具有强抗菌作用的小分子多肽，是生物体天然免疫防御系统的重要组成部分，最先由CBoman等经注射阴沟杆菌及大肠杆菌诱导惜古比天蚕蛹产生的具有抗菌活性的多肽，此后科学家在昆虫、被囊动物、两栖动物、鸟类、鱼类、哺乳动物及植物乃至人类等多种生物体中发现并分离获得内源性抗菌肽。     

鱼类铁调素生物学功能与体外表达的研究进展

<正>近年来，细菌性疾病频发，抗生素不规范使用导致细菌耐药性问题日益严重^[1]。研发新的抗菌药物，替代抗生素是解决细菌耐药性问题的一个方向。抗菌肽是具有抗菌作用的小分子多肽，相比于抗生素，不易产生耐药性，可作为抗生素耐药细菌治疗的潜在药物^[2-3]。其中鱼类铁调素(Hepcidin)具有广谱的抗菌活性，抗菌效果明显，已成为当前抗菌肽研究的热点。     

水产动物抗菌肽研究进展

抗菌肽是一类广泛存在于自然界生物体内的小分子多肽物质,为机体固有免疫系统的重要组成部分,对革兰氏阴性菌、革兰氏阳性菌、真菌、病毒和寄生虫等均具有较好的抑制或杀伤作用。抗菌肽具有无污染、无残留、广谱抗菌及不易产生耐药性等特点,有望代替抗生素用于水产动物病原性疾病的防控。近年来,抗菌肽已在水生甲壳动物、水产软体动物、鱼类和两栖类等水产动物中得到报道,但其分类和作用机制有待深入研究。本文对不同水产动物中的抗菌肽进行了分类,对各类抗菌肽的结构特征和功能进行了分析,并从直接杀伤作用、非膜靶向作用和免疫调节作用等三个方面对抗菌肽的免疫作用机制进行了分析,期望能够为今后在水产动物中开展抗菌肽的相关研究和应用提供一定的理论支持。     

Antiparasitic activity of the antimicrobial peptide HbβP‐1, a member of the β‐haemoglobin peptide family

A family of antimicrobial peptides (AMPs) derived from the β‐subunit of haemoglobin was recently isolated from channel catfish, Ictalurus punctatus, infected with Ichthyophthirius multifiliis (ich), an important freshwater fish parasite that causes ichthyophthiriosis. We previously discovered that one of these AMPs, HbβP‐1, had strong cidal activity against ich as well as another ectoparasite, Tetrahymena pyriformis. HbβP‐1 toxicity was specific, primarily affecting the trophozoite (trophont) stage of ich. Here, we show that HbβP‐1 acts more rapidly to kill smaller (presumably less mature) trophonts of ich, taking almost twice as long to kill larger trophonts (P < 0.0001). It acts more rapidly than an unrelated AMP, piscidin 1, which is haemolytic and also lethal to ich trophonts. HbβP‐1 is potently and selectively lethal to the trophont stage of the dinoflagellate ectoparasite, Amyloodinium ocellatum, one of the most important pathogens of warmwater marine fish. HbβP‐1 has no effect on the fish gill cell line feeder layer (G1B cells) used to propagate Amyloodinium, further suggesting a highly selective action. These findings suggest that HbβP‐1 or related AMPs might function in protecting marine as well as freshwater fish and that HbβP‐1 has highly selective activity against specific life stages of important fish ectoparasites.     

Bacteriocins and their applications for the treatment of bacterial diseases in aquaculture: a review

Aquaculture is one of the fastest growing food producing sectors in the world. The increase in the world population requires faster growth in aquaculture for better food availability and to overcome malnutrition. But this worldwide growth of aquaculture is overwhelmed by catastrophic fish diseases and spoilage during cultivation and preservation problems caused by pathogenic bacteria. Various remedies are available for food preservation and also from the bacterial diseases in the fish production. Due to the emergence of antibiotic resistance and adverse effects, an alternative to antibiotic is the need of the hour. The proteins such as bacteriocins, i.e. ribosomally synthesized antimicrobial peptides (AMPs) and possess antagonistic against closely related and other bacteria. These proteins are produced by most lineages of bacteria which are playing key roles in recognition and possess a cognate immunity system for self‐protection as well as host protection from infections. These proteins are potent immunomodulators with broad spectrum inhibition properties which are further used as novel therapeutic agents. In this review, we have tried to summarize the bacteriocins on the basis of their classifications, structural and functional attributes, mode of actions, bacteriocins isolated from fish and gut microbiota and presence of beneficiary bacteria in the fish gut. Further, this study highlighted where further research is a prerequisite to increase our basic understanding and search for novel bacteriocins to elucidate the proteins/peptides having antimicrobial properties for disease control in aquaculture as an alternative to antibiotics.     

Comparative activity and stability under salinity conditions of different antimicrobial peptides isolated from aquatic animals

This study reports the in vitro activity of six antimicrobial peptides (AMPs) produced by aquatic animals (most marine invertebrates): tachyplesin (Tach), magainin (Mag), clavanin (Clav), penaeidin (Pen), mytilin (Myt) and antilipopolysaccharide factor (ALF) against marine vibrios, filamentous fungi and yeast. Their stability under salinity conditions and seawater was also examined. The results showed that Mag, Myt and especially Tach and ALF (minimum inhibitory concentration<1.5 μM) had a potent activity against all tested vibrio species, whereas Clav and Pen were ineffective (up to 50 μM). With respect to the antifungal activity, each AMP had a different potency according to the fungal species. In general terms, Tach was the most potent peptide, followed by Mag. Interestingly, Tach, Myt and ALF had a significant effect on the filamentous fungus Fusarium solani that could be pathogenic to marine organisms. All AMPs had a tendency to decrease or lose their activity at high salinity (>225 mM NaCl). Tach and Myt were the most stable peptides, maintaining significant activity under seawater salinity (450 mM). Curiously, all peptides lost their effect under seawater conditions. The results suggest that Tach, ALF and Myt are the most promising candidates for potential therapeutic use in farmed-marine species, because all have a significant and broad antimicrobial activity maintained at high salinity.     

Cathelicidins enhance protection of channel catfish,Ictalurus punctatus,and channel catfish ♀ × blue catfish,Ictalurus furcatus ♂ hybrid catfish against Edwarsiella ictaluri infection

Cathelicidins are a class of antimicrobial peptides (AMPs) known to possess rapid and direct antimicrobial activities against a variety of microorganisms. Recently identified cathelicidins derived from alligator and sea snake were found to be more effective in inhibiting microbial growth than other AMPs previously characterized. The ability of these two cathelicidins along with the peptides, cecropin and pleurocidin, to protect channel catfish (Ictalurus punctatus, Rafinesque) and hybrid catfish (I. punctatus ♀ × blue catfish, Ictalurus furcatus, Valenciennes ♂) against Edwardsiella ictaluri, one of the most prevalent pathogens affecting commercial catfish industry, was investigated. Cathelicidin-injected fish (50 µg ml⁻¹ fish⁻¹) that were simultaneously challenged with E. ictaluri through bath immersion at a concentration of ~1 × 10⁶ CFU/ml had increased survival rates compared with other peptide treatments and the infected control. Bacterial numbers were also reduced in the liver and kidney of channel catfish and hybrid catfish in the cathelicidin treatments 24 hr post-infection. After 8 days of challenge, serum was collected to determine immune-related parameters such as bactericidal activity, lysozyme, serum protein, albumin and globulin. These immune-related parameters were significantly elevated in fish injected with the two cathelicidins as compared to other peptide treatments. These results indicate that cathelicidins derived from alligator and sea snake can stimulate immunity and enhance the resistance to E. ictaluri infection in channel catfish and hybrid catfish.     

钙对肉品质的影响研究进展

钙是最常见的营养元素之一,但最近的研究发现钙除了最基本的生理功能之外,还有改善肉质的作用,本文就钙改善肉质的研究进展及作用机理作一概述。     

鲆鲽类白化机理的研究进展

鲆鲽类体色白化，在苗种生产过程中常见。很多学者对其进行过研究，然而关于白化的机理仍然不清楚。本文就近年来国内外有关鲆鲽类白化机理的研究从营养、遗传、环境、生理等方面进行综述。     

盐度影响海水硬骨鱼类渗透压调节机理的研究与展望

盐度是硬骨鱼类生存环境中一个十分重要的生态因子,对于鱼类的存活、受精卵的发育以及仔鱼、幼鱼、成鱼的健康生长都是极为重要的。为了探索盐度的影响机理,本文对国内外的研究概况以及与海水硬骨鱼类渗透压调节相关的细胞、调节酶、调节激素、离子转运通道进行了详细的论述,并提出今后的研究方向和展望。     

鱼类性别相关基因及性别特异标记的研究进展

对动物性别的研究一直深受人们关注,以哺乳类为代表已经取得了许多可喜的成果。由于鱼类在脊椎动物系统进化中处于承前启后的地位,是脊椎动物中分布最广、种类最多的类群,具有多种多样的生物学特征和重大的经济价值,所以,对于鱼类性别决定机理的研究具有重大意义。本文主要介绍了鱼类性别决定相关基因和性别特异标记的研究进展。     

Evidence for synergism of the antimicrobial peptide piscidin 2 with antiparasitic and antioomycete drugs

Piscidins are potent, broad‐spectrum, host‐produced antimicrobial peptides (AMPs) that appear to constitute the most common AMP family in teleost fish. Here, we show that piscidin 2 has potent activity against the water mould Saprolegnia, one of the most important pathogens of freshwater fish. The minimum oomyceticidal concentration (MOC₁₀₀) of piscidin 2 against zoospores of three pathogenic isolates of Saprolegnia ranged from 12.5 to 25.0 μg mL^?1. This piscidin concentration is well within levels that have been estimated to be present in at least some fish (1–32.5 μg mL^?1). In the presence of either copper or malachite green, two drugs commonly used to treat water moulds, there was evidence for partial synergism (PSYN) with piscidin 2. There was also evidence for PSYN after exposure of the ciliate parasite Tetrahymena pyriformis to piscidin 2 plus copper. Our data provide further evidence that piscidins may be an important host defence against skin and gill pathogens and that the piscidin levels in host tissue might influence the success of drug treatments.