鱼类品种培育新技术

鱼类新品种的培育对水产养殖业的发展起着极其重要的作用。本文对可应用于鱼类新品种培育的新技术－－基因转移染色体片段转移、嵌合体制作技术、克隆、细胞融合以及航天育种技术做了简要概述,以期通过这些技术的综合应用能够创造出优质、高产、抗逆的鱼类新品种。     

1980—2007年大亚湾鱼类物种多样性、区系特征和数量变化

根据2004—2005年大亚湾海域底拖网鱼类调查数据,并结合1980—2007年的历史资料,分析了该海域鱼类的种类组成、区系特征、多样性、优势种和数量变化趋势.结果表明： 2004—2005年,大亚湾海域共记录鱼类107种,分属13目50科,以中下层鱼类的种类最多,为48种,其次是中上层和底层种类,分别为37种和21种.大亚湾鱼类区系具热带和亚热带特性,以暖水性种类占绝对优势,为97种,暖温性种类为10种.多样性指数以夏季最高（3.82）,其次是冬季（3.37）和秋季（3.00）,春季最低（2.40）.Pielou均匀度指数的季节变化情况与多样性指数相似.1980—2007年大亚湾海域鱼类群落特征发生了明显的变化：鱼类种类数减少,优势种更替明显.鱼类种类数由1980年的157种减少至1990年的110种,2004—2005年继续减少至107种;鱼类优势种由1980年以带鱼和银鲳等优质鱼为主,更替为以小型和低值的小沙丁鱼、小公鱼和二长棘鲷幼鱼为主.用包含年际变化趋势和季节性周期变化的回归模型模拟1980—2007大亚湾鱼类资源密度的变化,鱼类资源密度在1980—1999年和1990—2007年两个时期均呈下降趋势,但1990—2007年间下降幅度比1980—1999年间大;1980—1999年鱼类资源密度的季节波动幅度较平缓（振幅为0.099）,而1990—2007年的季节波动较大（振幅为0.420）,说明1990—2007年阶段大亚湾鱼类数量的季节变化更为显著.     

鱼类基因转移育种的几个问题

１９８５年,世界上第一批转基因鱼诞生。随后,鱼类基因转移迅速应用到培育高产、优质和抗逆的养殖鱼类新品种,并在解决发育生物学分子生物学和生理学等方面的难题中发挥了重要作用。目前,研究者已经建立了三种成熟的鱼类基因转移方法,即显微注射、电脉冲和精子携带法,证实了转移大受体鱼基因组中的整合、性腺传递、表达和转译表达产物的生物活性。最近,“全鱼”生长激素（ＧＨ）基因的克隆与应用,使快速生长转ＧＨ基因鱼的研     

碗莲杂交育种研究初报

莲是我国传统的著名花卉之一,素来深受人民所喜爰。作者试图通过有性杂交育种的途径,选育出适于家庭种植的荷花新类型——碗莲。在一九七九年进行品种间杂交的基础上,对其杂种一代进行了繁殖观察、选优试种,几年来的试验结果表明:选育的三个优良株系(7908—A、7903—B、7904—A)较亲本优越,有一定的观赏价值,是很有希望的碗莲新品种。本文报导了碗莲新品种选育的初步结果,     

鱼类转基因研究

本文综述了鱼类转基因研究的意义、鱼类基因转移研究的特点、转基因鱼的构建及检测技术、我国鱼类转基因研究的进展和鱼类基因转移研究中存在的主要问题。     

鱼类转基因研究

本文综述了鱼类转基因研究的意义、鱼类基因转移研究的特点、转基因鱼的构建及检测技术、我国鱼类转基因研究的进展和鱼类基因转移研究中存在的主要问题。     

鱼类基因转移的研究战略

本文总结了八五年以来世界各实验室在鱼类基因转移研究方面的概况。指出生长激素(GH)基因转移已形成第一热点,分析了形成这一热点的原因,提出作为第一主攻方向应进一步解决启动子、“全鱼”基因和生长速度测定等问题。认为抗冻蛋白(AFP)基因转移已形成第二热点。但在我国应把珠蛋白基因转移作为第二主攻方向。文章最后提出了在重视“导弹”技术的同时,应重视和加强“霰弹”技术的研究,以加速鱼类基因转移技术的发展。     

“七五”期间我国农业生物技术发展的回顾

一、概况我国自第七个国民经济五年发展计划以来,作为增强农业发展后劲的重要战略措施,发展农业生物技术受到了广泛重视,在中央及有关部委领导关心下,农业生物技术被正式列入国家科技发展计划,在基础设施建设、科研经费投入、人才队伍建设等方面得到了较大支持. 我国农业生物技术研究起步于七十年代中期,但是由国家有计划地组织研究是在“七五”期间开始的.目前的研究领域主要有: 1.生物技术改良作物遗传性状利用花药培养技术培育作物新品种;植物细胞培养和融合技术以及体细胞无性系变异体离体筛选技术在培育作物优良新品种中的应用;应用基因工程技术定向转移优良目的基因,改良作物品种.还有蔬菜、花卉和果树等植物的快繁、脱毒等.     

人工诱变技术在植物抗病育种中的应用(综述)

介绍人工诱变技术在植物抗病育种中的主要成就,并探讨其发展方向及前景。人工诱变技术与杂交育种、基因转移及离体筛选等手段相结合,提高了育种效率,拓宽了抗病育种的范围。该技术在植物抗病育种中的成功应用,将有利于培育植物抗病新品种,促进农业的增产增收及可持续发展。     

应用流式细胞术测定17种中国野生蔷薇核DNA含量

以17种中国野生蔷薇为试材,采用改良的LB 01裂解液,以4种不同的标准植物——大豆（Glycine max Merr.‘Polanka’）、绿豆（Vigna radiata（L.） Wilczek）、番茄（Lycopersicon esculentum Miller）和玉米（Zea mays L.）为外标,以二倍体材料丽江蔷薇（Rosa×lichiangensis Yü et Ku）为内部参照,利用流式细胞术对其核DNA含量及染色体倍性进行检测,并采用常规染色体压片法验证倍性准确性。本研究首次检测了3个二倍体种——商城蔷薇（Rosa shangchengensis T.C.Ku）、广东蔷薇（Rosa kwangtungensis Yü et Tsai）和无刺刺梨（Rosa roxburghii f.inermis S.D.Shi）,1个三倍体种——伞房蔷薇（Rosa corymbulosa Rolfe）和1个四倍体种——弯刺蔷薇（Rosa beggeriana Schrenk）的核DNA含量及基因组大小。结果表明,流式细胞术检测结果与常规染色体压片法结果一致,可对中国野生蔷薇的倍性研究进行补充。本研究结果可丰富中国蔷薇属植物的细胞遗传学背景资料并为繁育新品种提供理论依据。     

牛卵核移植技术的应用

用去核的牛卵母细胞进行核移植,形成重构胚,胚胎移植后,可产生克隆牛。将克隆牛的肉和奶制成肉粉和奶粉饲喂大鼠,大鼠的生理功能不受影响。牛卵核移植技术为珍稀动物的保护提供了一条重要途径,对于细胞治疗的研究也具有重要意义。通过牛卵核移植技术,可构建异种克隆胚胎,用以研究核质相互作用。将牛卵核移植技术和体细胞基因修饰技术相结合,可生产转基因克隆牛。     

一种非手术性小鼠胚胎移植技术

为了提高非手术性小鼠胚胎移植技术的成功率,利用塑料移植导管模拟非手术胚胎移植过程,通过观察染料在子宫角的分布而评估胚胎移植效果,并在此基础上将自然妊娠3.5 d的小鼠囊胚经子宫颈移植受体小鼠。结果表明:将CD-1小鼠囊胚移植假孕2.5 d小鼠单侧子宫角,平均70.9%的胚胎能够发育至成活新生仔鼠,建立了高效非手术性小鼠胚胎移植技术。该方法简便快捷、不易污染、费用低,无需专业的手术器械,且符合实验动物伦理原则,完全可以取代手术法胚胎移植技术,更重要的是,它为人类和其他大动物的胚胎移植提供了研究模型。     

Below-ground nitrogen transfer between different grassland species: Direct quantification by 15N leaf feeding compared with indirect dilution of soil 15N

Nitrogen (N) transfer from one species to another is important for the N cycling in low-input grassland. In the present work, estimates obtained by an indirect ¹⁵N dilution technique were compared with estimates obtained by a direct ¹⁵N leaf feeding technique over two complete growing seasons in red clover-ryegrass and white clover-ryegrass mixtures under field conditions. The direct technique confirmed that N transfer between clovers and ryegrass is a bi-directional process. The transfer of N from both clovers to ryegrass occurred within 25 days upon the first labelling event. A very high N transfer occurred from white clover to the associated ryegrass, 4.5 and 7.5 g m⁻² in the 1st and 2nd production year, respectively. The corresponding values for transfer from red clover to the associated ryegrass were 1.7 and 3.6 g m⁻². Quantified relatively to the total above-ground N content of white clover- ryegrass and red clover-ryegrass mixtures, the N transfer exceeded 50% and 10%, respectively, in three out of seven harvests. The N transfer from ¹⁵N labelled grass to associated clovers constituted a relatively constant proportion of approx. 8% of the above-ground N content of the mixtures. Estimates based on the soil ¹⁵N dilution technique generally underestimated the net N transfer by more than 50% compared to the direct ¹⁵N labelling technique. Furthermore, the indirect ¹⁵N dilution technique estimated only marginal differences between red and white clover in the quantities of N transferred, whereas the direct ¹⁵N labelling technique showed the N transfer from white clover to the associated ryegrass to be significantly higher than that involving red clover. It is concluded that N transfer is a much more dynamic and quantitatively important process in grassland than previously recognised. This revised version was published online in June 2006 with corrections to the Cover Date.     

Comparative Study on the Suitability of Two Techniques for Measuring the Transfer of Lipophilic Drug Models from Lipid Nanoparticles to Lipophilic Acceptors

Due to their particle size in the submicrometer range, lipid nanoparticles are suitable for parenteral administration. In order to obtain information on their potential in vivo performance, a simple and effective in vitro assay to evaluate the drug release behavior of such particles is required. This study compares the use of different experimental setups for this purpose. Lipid nanoparticles from trimyristin which were loaded with fluorescent lipophilic drug models (a temoporfin and Nile red) were used as donor particles. The transfer of the two drug models to multilamellar vesicles (MLV) and emulsion droplets as lipophilic acceptor compartments was examined. The determination of the transferred substance was performed either after separation by centrifugation or by an in situ flow cytometric technique. The transfer of temoporfin was slow to the acceptor MLV and very rapid to the acceptor emulsion. With both acceptors, the transfer of temoporfin stopped at a concentration much lower than the theoretical equilibrium values. The transfer of the less lipophilic drug Nile red was very rapid to both acceptors with equilibrium concentrations close to the expected values. The transfer results of temoporfin especially to the acceptor MLV obtained with the two detection techniques were comparable while the centrifugation technique indicated an apparently higher Nile red transfer rate than the flow cytometric technique. Both techniques are equally suitable to study the transfer of temoporfin, while the flow cytometric technique is advantageous to measure the very rapid transfer of Nile red.Key words: drug transfer, flow cytometry, lipid nanoparticles, liposomes, ultracentrifugation     

Direct cell to cell transfer of organelles by microinjection

Summary A new technique for transfer of organelles to plant cells is presented. The organelles are removed from the donor protoplast by micromanipulation and microinjected directly into the acceptor cells. First results obtained by this technique for transfer of chloroplasts and fluorescently labelled mitochondria are presented.     

Handmade cloning: the future way of nuclear transfer?

The topic of this review is an alternative technique for somatic cell nuclear transfer. Removal of the zona pellucida facilitates manipulations of mammalian oocytes and early embryos, and problems related to their subsequent culture are commonly overestimated. This approach enables radical modifications to somatic cell nuclear transfer, and the handmade cloning (HMC) technique is now successfully applied to an increasing numbers of species. HMC radically decreases costs and the need for a skilled workforce; furthermore, it increases productivity, enables cryopreservation, and results in birth rates comparable, or even higher, than those achievable by micromanipulation-based traditional cloning (TC). The new technique can accelerate technology transfer and standardization and, eventually, might contribute to the widespread application of cloning. Additionally, HMC offers unique possibilities for the automation of somatic cell nuclear transfer.     

Reconstruction of the thumb with a trimmed-toe transfer technique

The trimmed-toe transfer is a new modification of the existing great-toe transfer technique for thumb reconstruction. This procedure was devised to circumvent patient concerns regarding overly large reconstructed digits following total great-toe-to-hand transfer. This technique involves reduction of both the bony and soft-tissue elements along the medial aspect of the transferred great toe in order to produce a more normal sized thumb. Follow-up of the initial 20 patients from 1983 to 1986 demonstrates good stability, grip strength, and pinch strength. Although compared with total great-toe transfer a modest reduction in joint motion of trimmed toes has been observed, the overall appearance and usefulness of the reconstructed thumbs have been excellent.     

Capacity of aquatic bacteria to act as recipients of plasmid DNA.

A total of 68 gram-negative freshwater bacterial isolates were screened for their ability to receive and express plasmids from Pseudomonas aeruginosa donors. The plate mating technique identified 26 of the isolates as recipient active for the self-transmissible wide-host-range plasmid R68; 10 were recipient active by R68 mobilization for the wide-host-range plasmid cloning vector R1162. Frequencies of transfer were compared by using three conjugal transfer procedures: broth, plate, and filter mating. For every recipient tested, a solid environment was superior to a liquid environment for transfer. The broth mating technique failed to demonstrate R68 transfer in 63% of the recipient-active isolates. Filter mating, in general, yielded the highest transfer frequencies. The more-rapid plate mating procedure, however, was just as sensitive for testing the capacity of natural isolates to participate in conjugal plasmid transfer.     

Capacity of aquatic bacteria to act as recipients of plasmid DNA

A total of 68 gram-negative freshwater bacterial isolates were screened for their ability to receive and express plasmids from Pseudomonas aeruginosa donors. The plate mating technique identified 26 of the isolates as recipient active for the self-transmissible wide-host-range plasmid R68; 10 were recipient active by R68 mobilization for the wide-host-range plasmid cloning vector R1162. Frequencies of transfer were compared by using three conjugal transfer procedures: broth, plate, and filter mating. For every recipient tested, a solid environment was superior to a liquid environment for transfer. The broth mating technique failed to demonstrate R68 transfer in 63% of the recipient-active isolates. Filter mating, in general, yielded the highest transfer frequencies. The more-rapid plate mating procedure, however, was just as sensitive for testing the capacity of natural isolates to participate in conjugal plasmid transfer.     

Replica plating of mammalian cells using low melt agarose

We have developed a technique to replica plate mammalian cells grown on plastic dishes using low melt agarose. This method is simpler than previously described methods that use polyester membranes to grow and transfer cells. We have tested the effectiveness of this technique on normal and immortal cell lines and have found that we can transfer cells with an efficiency of 80–90%. We have used this technique to rapidly screen clones for insertion of a lentivirally encoded gene without a selectable marker.