转基因鱼的研究进展及食品安全性

随着转基因技术的发展，各种转基因动物及转基因植物相继出现并应用于生产实践，给人们带来了巨大的利益。自1985年，世界上第一批转基因鱼诞生后，鱼类基因转移技术很快应用到鱼类育种中。20年来国内外主要进行了快速生长、抗寒（耐寒）、抗病等方面的转基因鱼的研究。本文主要介绍了几种常用的鱼类的基因转移技术和检测方法，转基因鱼的研究现状，并对其的食用安全性进行了讨论。     

鱼类基因转移技术研究进展

基因转移为鱼类遗传育种开辟了一条新的途径。自1985年第1例转基因鱼问世至今已获得十几种转基因鱼，在促进生长，提高鱼类抗逆性、抗病性等方面取得了巨大的成绩。本文主要结合国内外关于鱼类基因转移成功的报道，分析了各种转基因技术的可行性和优缺点，并对其作用机理、适用对象、条件优化、转化效率等几个方面做了概括性叙述。     

转“全鱼”GH基因黄河鲤胚胎发育观察研究

正转基因鱼是借助生物技术手段,将外源基因导入受体鱼内,通过外源基因的定点整合,使其优良性状在鱼体上得以表达,并经过人工选育而培育出的一类性状优良、遗传稳定而且具有较高经济价值的鱼类。中国科学院院士朱作言等于1985年率先在世界上成功研制出了转基因鱼,并建立了转基因鱼模型,此后鱼类基因转移技术在世界范围内迅速发展,     

转基因鱼所引发的思考

转基因鱼是借助生物技术的手段，将外源基因转入鱼体，通过外源基因的定点整合，使其优良性状在鱼体上得以表达，并经过人工选育而培育出的一类性状优良、遗传稳定且具有较高经济价值的鱼类。鱼类基因转移技术最先在我国建立。1985年我国科学家朱作言等人成功获得了转基因鲫，它证实了外源基因在受体鱼内的整合、     

转基因技术在鱼类育种中的应用前景

<正> 近10年来,随着转基因技术的日趋完善,转基因动物的研究得到迅速发展,为动物定向育种开辟了新的途径,在鱼类育种中也已获得了迅速发展。1 转基因鱼的产生及育种意义 由于鱼类属于低等脊椎动物,具有怀卵量大,容易进行胚胎体外操作等特点,用鱼类进行基因转移较之用其他动物既经济又有世代繁殖快等优     

鱼类转基因研究中存在的问题及对策

随着生物技术日新月异的变化 ,人类的技术思想有了质的飞跃。基因转移技术就是这种技术思想酝酿的创新点之一。鱼类是人类食物中主要的蛋白质来源之一。青鱼、草鱼、鲢鱼、鳙鱼、鲤鱼、广东鲮等是我国主要的淡水养殖鱼类。同农业一样 ,发展淡水养殖业也存在品种改良问题 ,发展和完善基因转移技术 ,将优良性状的基因 ,如生长激素、干扰素、抗冻蛋白、抗病等基因导入鱼受精卵内以达到遗传改良 ,为培育高产、优质及抗逆的养殖鱼类新品系提供新途径[1] [2 ] 。由于鱼类是低等脊椎动物 ,自身优势明显而使得转基因在鱼类研究中取得了重大的胜利。…     

转基因技术在鱼类育种上的应用

<正>随着转基因技术进入实用化阶段,其负面影响也逐渐显露出来,包括转基因品种对人类健康、生态环境等的安全性问题。但作为一种先进的育种手段,尽管人们对转基因技术有各种怀疑,其仍将在鱼类育种中发挥重要作用。一、转基因技术概述转基因技术是一种物种间的基因改良技术。转基因鱼是指将外源基因导入受体鱼的基因组内,并使其稳定整合并能遗传给后代的鱼类。目前,显微注射法是比较常用和有效的基因导入方法。近年来,作为分子生物学领域当     

总论

010969transfer水产养殖基因转移技术=Genetechnology及n squaeulture〔刊,英]/Levy JA,Marins LF,SallChezA//Hydrobiologia一2000,420(1)一91一94 水产养殖基因转移技术是将一种生物的基因转移给另一种生物以改良其特性,诸如提高生长率、饲料利用率、抗病、以及拓宽生态范围等。转基因生产鱼的程序如下:(1)设计构成遗传DNA;(2)将基因转移给胚细胞;(3)筛选转基因鱼;(4)测定转基因的表现与表型;(5)研究遗传;(6)筛选转基因稳定线。遗传改变生物特性具有显著的经济效益,但对生态环境有所威协,有利亦有弊。由于生产的转基因鱼供人类消费,…     

鱼类转基因技术研究进展

转基因技术作为鱼类育种的新途径,自20世纪80年代第一个转基因鱼模型建立以来,已经历30多年,获得了30多种转基因鱼。在提高生长速度、抗逆性等研究中取得了巨大的成就。本文主要对鱼类转基因研究现状及方向作以综述,并对其发展趋势进行展望。     

转基因鱼研究中存在的问题

针对转基因鱼技术中关于启动子和结构基因的选配、外源基因的定点整合、外源基因的可控表达、转基因鱼鉴定、建立转基因鱼纯系个体以及转基因鱼应用安全问题几个方面进行了论述.     

Increased ability to compete for food by growth hormone-transgenic coho salmon Oncorhynchus kisutch (Walbaum)

In salmonids, growth hormone (GH) stimulates growth, appetite and the ability to compete for food. This study tested the hypothesis that increased GH levels in GH-transgenic coho salmon Oncorhynchus kisutch (Walbaum) increase competitive ability through higher feeding motivation. The transgenic strain of salmon used contained a gene construct consisting of the sockeye metallothionein-B promoter fused to the type 1 growth gene coding region. The transgenic animals (mean size = 250 g) were F₁ individuals. In six consecutive feeding trials, the intake of contested food pellets by size-matched pairs consisting of one control (1 year older non-transgenic coho salmon) and one GH-transgenic coho salmon was compared. Pellets were provided sequentially until neither fish took three consecutive pellets; the identity of the fish taking each pellet was noted. Calculated on the three first pellets offered at each feeding trial, the transgenic coho salmon consumed 2.5 times more contested pellets than the controls, supporting the hypothesis that GH transgenesis increases the ability to compete for food. Overall, the transgenic fish consumed 2.9 times more pellets that the non-transgenic controls, indicating a high feeding motivation of the transgenic fish throughout the feeding trials. It appears that GH transgenesis and GH treatments can induce similar changes in the feeding behaviour of salmonids. Depending on how transgenic and wild individuals differ in other fitness-related characters, escaped GH transgenic fish may compete successfully with native fish in the wild.     

转生长激素基因中华倒刺鲃的构建及其检测

用从斑点叉尾鮰(Ictalurus punctatus)cDNA文库克隆到的生长激素基因,与鲤β肌蛋白启动子、大麻哈鱼生长激素基因的poly(A)终止信号序列等调控元件共同构建了表达重组质粒pFV2 cfGH。提取重组质粒,用精子载体法导入中华倒刺鲃(Spinibarbus sinensis)的受精卵中,经孵化培养成转基因成鱼。抽提423尾转基因实验鱼血总DNA,经PCR检测表明:斑点叉尾鮰生长激素基因已导入中华倒刺鲃基因组中,导入率为17.26%。同时通过RT-PCR技术检测阳性中华倒刺鲃中生长激素基因的表达情况。     

转生长激素基因鲤的快速生长效应及传代

报道了转生长激素基因鲤阳性群体的建立科“超级鲤”的获得。给出了“超级鲤”和对照组连续4年的生长实验结果及“超级鲤”子代连续3年的生长对照的体重数据。结果显示,外源生长激素基因对受体鲤具有快速生长效应,但具有这种超速生长作用的个体在转基因鲤群体中占极少数。此效应能传递给子代,子代中快速生长个体的比例大大高于转基因实验群体。     

人生长激素基因在团头鲂和鲤中的整合和表达

采用显微注射方法，将带有小鼠ＭＴ－１基因启动顺序与人生长激素ｈＧＨ基因顺序重组的线状ＤＮＡ片段，注入团头鲂和鲤的受精卵，获得成活的实验鱼。经斑点、Ｓｏｕｔｈｅｒｎ杂交、Ｎｏｒｔｈｅｒｎ杂交、放射免疫和酶联等方法检测，表明外源基因在受体鱼中得到整合、转录、翻译和表达，并具促生长效应。转基因雌鱼和雄鱼有性繁殖所获得的子鱼带有外源基因，表明外源基因能通过性细胞传递给子代，并仍具促生长效应。     

Utilization of Transgenic Fish in Developing Countries: Potential Benefits and Risks

Recombinant DNA and gene transfer technology now allow the transfer, inheritance and expression of specific DNA or gene sequences into fish. Preliminary results on the performance of the resulting transgenic fish have been quite dramatic in some cases, especially when growth hormone genes are transferred. Utilization of high performance transgenic fish has the potential to greatly increase aquaculture production in developing countries and increase the income of poor farmers. Growth of some transgenic fish has been increased more than 10-fold in laboratory conditions. Response appears to be greatest in unimproved fish, which in most cases would benefit developing countries the most. The potential increase in production and production efficiency from successful transgenic fish application could relieve pressure on habitat destruction for food production, relieve pressure on overfished natural stocks and discourage introduction of exotic species. Application of transgenic fish in aquaculture has just begun and could expand within a few years. However, prior to commercialization of transgenic fish, public education, environmental risks and food safety issues should be addressed. Genetically improved fish generated by recombinant DNA technology probably do not pose any greater risk to the environment than fish genetically improved through traditional selective breeding, but environmental risk data is lacking to verify this hypothesis. Environmental risk data will be needed in a case-by-case basis until more is known concerning the aquaculture potential and ecological risk of transgenic fish. Research institutions need to address the lack of environmental risk data to help ensure that any future application of transgenic fish in developing (and developed) countries be done in an environmentally and socioeconomically sound manner. Socioeconomic study is lacking for detailed cost-benefit analysis, and policy research is needed for proper application or regulation of transgenic fish in these countries.     

Transgene integration - an analysis in autotransgenic Labeo rohita Hamilton (Pisces: Cyprinidae)

Transgenic Labeo rohita founder population was analyzed for the presence of autotransgene having histone 3 promoter and growth hormone (GH) cDNA (LRH3-GHcDNA) or total GH gene (LRH3-GH2.8) by PCR with transgene specific primers. Transgene specific amplification was seen with LRH3-GHcDNA in five out of seven individuals and all three fishes with LRH3-GH2.8, indicating their transgenic nature. Transgene integration was also studied by Southern hybridization of DNA isolated from blood of the transgenic fishes with two different probes (histone 3 promoter and cDNA of L. rohita). Autotransgene integration was confirmed in all PCR positive transgenic individuals. The site of integration of the transgene in the genome of the four transgenic fish could be determined by inverse PCR. Two individuals showed integration at the same site whereas in the remaining two individuals the integration sites were different.     

Effects of 3,5,3′-triiodo-L-thyronine (T3) and 6-n-propyl-2-thiouracil (PTU) on growth of GH-transgenic coho salmon, Oncorhynchus kitsutch

GH-transgeniccoho salmon (Oncorhynchus kitsutch) juveniles were fed diets containing 3,5,3-triiodo-L-thyronine (T₃; 30 ng/g fish) or 6-n-propyl-2-thiouracil (PTU; 20 ug/g fish), to assess the effect of these drugs on the physiology, growthand survival in comparison with untreated transgenicand non-transgenic salmon. After 84 days, food intake, feed efficiency, survival, growth, hepato-somatic index (HSI), viscera-somatic index (VSI), plasma L-thyroxine (T₄), T₃and growth hormone (GH) levels,and cranial morphological abnormalities were determined. Growth of transgenic salmon was significantly faster than the nontransgenic salmon,and was increased by exogenous T₃and reduced by PTU. Food intake of transgenic salmon was higher than that of the nontransgenic group, but was reduced by exogenous PTU administration. Food conversion efficiency of transgenic salmon was lower than that of nontransgenic salmon,and also was increased by T₃ but reduced by PTU in the transgenic fish. The survival rate in all transgenic groups was significantly higher than that of nontransgenic,and transgenic T₃and PTU treatment groups showed higher survivals than the transgenic-control group. The HSIand VSI of the transgenic fish were higher than the nontransgenic fish;and both parameters in the transgenic salmon were increased by PTU, but reduced by T₃. The plasma T₄ level in transgenic salmon was approximately 1.5-fold higher relative to the nontransgenic fish, whereas no difference was observed among the transgenic groups. Plasma T₃ levels in transgenic salmon were also approximately 2-fold higher relative to the nontransgenic fish. However, the plasma T₃ level in transgenic animals was increased by exogenous T₃ administration, but was reduced by exogenous PTU to that observed in nontransgenic salmon. The plasma GH level of transgenic fish was higher than that of the nontransgenic salmon,and the level was increased by the exogenous T₃, whereas exogenous PTU did not reduce significantly GH levels in transgenic salmon. Transgenic fish also displayed cranium, jawand opercular abnormalities typical of the effects of this gene construct incoho salmon, indicating that some imbalance in growth processes has been induced. However, these abnormalities (especially cranial disruptions) were diminished by administration of exogenous PTU. In conclusion, exogenous T₃and PTU treatments can induce hyperthyroidismand hypothyroidism, respectively,and have inverse effects on growthand skeletal abnormalities of transgenic salmon constitutively expressing GH.     

Development of Cre–loxP technology in zebrafish to study the regulation of fish reproduction

One cannot seek permission to market transgenic fish mainly because there is no field test or any basic research on technological developments for evaluating their biosafety. Infertility is a necessary adjunct to exploiting transgenic fish unless completely secure land-locked facilities are available. In this study, we report the generation of a Cre transgenic zebrafish line using a cytomegalovirus promoter. We also produced fish carrying the Bax1 and Bax2 plasmids; these genes were separated by two loxP sites under a zona pellucida C promoter or were driven by an anti-Müllerian hormone promoter. We inserted a red fluorescent protein gene between the two loxP sites. After obtaining transgenic lines with the two transgenic fish crossed with each other (Cre transgenic zebrafish x loxP transgenic zebrafish), the floxed DNA was found to be specifically eliminated from the female or male zebrafish, and apoptosis gene expressions caused ovarian and testicular growth cessation and degeneration. Overexpression of the Bax1 and Bax2 genes caused various expression levels of apoptosis-related genes. Accordingly, this transgenic zebrafish model system provides a method to produce infertile fish and may be useful for application to genetically modified fish.     

转基因鱼研究中存在的问题

针对转基因鱼技术中关于启动子和结构基因的选配、外源基因的定点整合、外源基因的可控表达、转 基因鱼鉴定、建立转基因鱼纯系个体以及转基因鱼应用安全问题几个方面进行了论述。