圖注：A,，綠色熒光顯示在正常培養(yǎng)的細(xì)胞中,，石斑魚hepcidin 均勻分布于細(xì)胞核和細(xì)胞質(zhì)中；B,，在病毒感染細(xì)胞后,，hepcidin多肽凝聚于細(xì)胞邊緣（箭頭所示），形成屏障,，發(fā)揮抗病毒作用,。
石斑魚是熱帶和亞熱帶地區(qū)最重要的海水養(yǎng)殖魚類品種之一，據(jù)聯(lián)合國(guó)糧農(nóng)組織（FAO）統(tǒng)計(jì),，全球石斑魚年產(chǎn)量2007年已接近20萬(wàn)噸,，經(jīng)濟(jì)價(jià)值巨大。然而,，在大規(guī)模和高密度人工養(yǎng)殖條件下,，石斑魚的養(yǎng)殖成活率還不到40%，制約石斑魚養(yǎng)殖業(yè)健康可持續(xù)發(fā)展的主要瓶頸在于各種傳染性疾病的暴發(fā)和流行,。由于大量使用抗生素易造成病原耐藥性,、環(huán)境污染和食品安全等問(wèn)題，從海洋生物中發(fā)現(xiàn)天然抗菌和抗病毒物質(zhì),，發(fā)展可替代抗生素的免疫防控技術(shù),，已成為研究發(fā)展新趨勢(shì)。
中科院南海海洋研究所海洋生物資源可持續(xù)利用重點(diǎn)實(shí)驗(yàn)室（LMB）秦啟偉研究員領(lǐng)導(dǎo)的團(tuán)隊(duì),，從病毒感染后的赤點(diǎn)石斑魚脾組織差減文庫(kù)中成功克隆出2個(gè)新的抗菌肽基因EC-hepcidin1和EC-hepcidin2,。這兩個(gè)基因分別由267和263個(gè)堿基組成，編碼88和87個(gè)氨基酸,，其中每個(gè)多肽分子含有4個(gè)半胱氨酸殘基和2對(duì)二硫鍵,，兩個(gè)基因之間的相似度為79%。其基因組結(jié)構(gòu)與哺乳動(dòng)物的相似,，包括3個(gè)外顯子和2個(gè)內(nèi)含子,。石斑魚Hepcidin基因廣泛表達(dá)分布于魚體各組織，在病毒,、細(xì)菌和真菌病原感染后,，基因表達(dá)顯著升高，其中,，在肝臟組織中的表達(dá)量最高,。人工合成包含有2對(duì)二硫鍵的多肽具有很強(qiáng)的殺菌和抗病毒活性，是首次報(bào)道成功合成的具有很強(qiáng)生物功能活性的Hepcidin多肽分子,，在防治海水魚類重大病毒病方面具有很好的應(yīng)用前景,。
研究成果已于近日發(fā)表在農(nóng)林水產(chǎn)類國(guó)際著名期刊Fish & Shellfish Immunology, 2011，F(xiàn)ebruary,，30（2）：559-568,，并被選為該雜志的研究亮點(diǎn)(Research highlight)文章。論文發(fā)表后已在國(guó)際上引起了關(guān)注,，韓國(guó)和羅馬尼亞等國(guó)科學(xué)家致函通訊作者秦啟偉,，表示出對(duì)該研究的濃厚興趣。
該研究受到國(guó)家杰出青年基金,、973計(jì)劃項(xiàng)目和中科院知識(shí)創(chuàng)新工程重要方向項(xiàng)目資助,。（生物谷Bioon.com）
生物谷推薦原文出處：
Fish & Shellfish Immunology, 2011，F(xiàn)ebruary,，30（2）：559-568
Molecular cloning and characterization of two novel hepcidins from orange-spotted grouper, Epinephelus coioides.
Zhou JG, Wei JG, Xu D, Cui HC, Yan Y, Ou-Yang ZL, Huang XH, Huang YH, Qin QW.
Orange-spotted grouper, Epinephelus coioides is one of the most important economic species of marine-cultured fish in China and Southeast Asia countries. However, very little information of the innate immune mechanisms against microbial pathogens is available in grouper, Epinephelus sp. Hepcidin, as an antimicrobial peptide (AMP), is a very important component in the innate immune system and widespread in fish. In this study, two novel types of hepcidin gene (designated EC-hepcidin1 and EC-hepcidin2) were cloned from E. coioides. They consist of open reading frames (ORFs) of 267bp and 263bp encoding the putative peptides of 88 and 87 amino acids, respectively. The homologous identity of deduced amino acid sequences between EC-hepcidin1 and EC-hepcidin2 is up to 79%, and predicted mature regions of both them have four cysteines residues. Genomic DNAs of both EC-hepcidin1 and EC-hepcidin2 consist of three exons and two introns. RT-PCR results showed that EC-hepcidin1 transcript was most abundant in liver and less in stomach. However, the transcript of EC-hepcidin2 was only detected in liver. The expressions of both EC-hepcidins were up-regulated by microbial and viral challenges, and iron overload, respectively, and EC-hepcidin1 was more responsive. The growth of Gram-negative bacterium of Vibrio vulnificus and Gram-positive bacterium of Staphylococcus aureus was inhibited by synthetic EC-hepcidins, and EC-hepcidin1 displayed stronger antimicrobial activity. The replication of Singapore grouper iridovirus (SGIV) was inhibited in the EC-hepcidin1 and EC-hepcidin2 over-expressed stable transfected fish cell lines (GS/pcDNA-Hep1, GS/pcDNA-Hep2) indicative of the antiviral activity of EC-hepcidins. These data should offer important information on the antimicrobial and antiviral roles of EC-hepcidins, and will be help to the better understanding of molecular mechanisms of grouper innate immunity.
