生物技术在养羊业科学研究中的应用

介绍了冷冻精液、胚胎移植、胚胎冷冻、胚胎分割、体外受精、核移植克隆、基因导入等技术。这些技术的应用使养羊业育种和生产水平大为提高,产生了显著的经济效益。同时,为养羊业科研和生产开辟了新的途径。     

牙鲆胚胎玻璃化冷冻技术研究

对名优经济鱼类牙鲆(Paralichthys olivaceus)胚胎的玻璃化冷冻技术方法进行了研究。筛选出了适合于牙鲆胚胎平衡和培养的基础液BS2,对牙鲆不同时期胚胎在玻璃化液VS2中的耐受能力进行了研究,随着平衡时间的延长,胚胎成活率逐渐降低,4-5对肌节期、16-20对肌节期、尾芽期表现出对玻璃化液较强的适应能力。对洗脱液的种类和浓度进行了筛选,结果显示0．125mol／L．蔗糖洗脱成活率最高。在室温(21～22％)和6℃下分别对牙鲆不同时期胚胎在VS1中的成活率进行了比较研究,结果显示出15—20对肌节期在室温下的成活率高于低温,其它时期胚胎低温下的成活率高于室温。利用VS4、VS2、VS3分别对牙鲆尾芽期、肌效应期、出膜前期胚胎进行玻璃化冷冻保存,取得了5粒成活胚,4粒孵化出膜,成活时间为14～67h。     

国外简讯两则

日本德岛县某试验场试验用冷冻未受精卵繁殖肉牛获得成功。该试验利用未受精卵进行体外受精,再移到牛体内繁殖。此技术在世界上属首次成功。该试验场开发出除去卵细胞内水分的技术,结合通过与高品质的冷冻精子结合,在必要时可以用很低的成本繁殖出优质肉牛。(通讯员郭和平)     

等温DSC研究高韧性低收缩环氧体系固化过程中的玻璃化现象

对于环氧树脂等温固化研究一般集中于固化温度高于体系完全固化的玻璃化温度,文中在固化温度低于体系完全固化的玻璃化温度的条件下,对一种高韧性低收缩环氧树脂体系的等温固化行为进行研究,对试样先进行等温固化再进行非等温差示扫描量热(DSC)分析,可以在DSC曲线上观察到一吸热峰,标志体系开始发生玻璃化转变并进入结构松弛阶段。通过分析DSC数据得到体系各固化时间的固化度和玻璃化温度,并且用Kamal方程对实验数据进行拟合,结果表明体系的玻璃化时间与进入扩散控制的时间相一致,从而可以通过玻璃化时间来判断体系控制步骤的变化。     

利用免费的热能——空气压缩机的热能回收再利用系统

在生产压缩空气时必然会产生大量热能。如果把这些热能利用起来，就可以将空气压缩机的效率提高到94％左右。为了实现这一目标，有的企业已经在现有的空压机站补装了设备和系统，例如简单安装一台热交换设备。     

相互缠结的PMMA/SPS复合水基微乳液的研究Ⅱ.体系反应前后的粒度分布及形态表征

将聚苯乙烯磺化制成聚苯乙烯离聚体（SPS），利用相反转技术，将磺化聚苯乙烯离聚体制成具有纳米级稳定的水基微乳液，利用SPS微粒核为反应场所，引发另一单体MMA聚合，制备具有相互缠结结构的PMMA／SPS复合水基微乳液。通过粒度分布仪、透射电镜等分析仪器对体系反应前后粒径形态、大小变化进行了探讨；用DSC仪器分析了复合材料的玻璃化转变，发现体系具有良好的相容性。     

世界首条大功率太阳能LED路灯系统投入使用

全球首个双线双结大面积硅基高效薄膜太阳能电池项目在南昌竣工试产。江西赛维百世德太阳能高科技有限公司的这一项目，初期达到8．5％的稳定转换率，远高于目前非晶硅单结技术6％的转换率，并且随后将不断提高至12％。     

更利于细胞的培养——新型通风供气系统为细胞培养提供了有效的空气流通

培养中的细胞能够茁壮成长，需要成分含量、比例非常精确的空气。但是，面对变化无穷的细胞培养条件，送风系统往往“反应迟钝”，不能及时做出相应的调整。Bioengineering公司研发生产的新型无死角送风系统很好地解决了这一问题，保证了所输送空气的组成成分和DH值的稳定。[编者按]     

冷水机利用变流量冷冻水的若干设计问题

如今在市场上使用的变水量冷冻系统大都是实行二次双环路的形式。虽然在国内外的很多家生产企业都已经陆陆续续地使用这种配置方式来进行生产和作业，但是二次双环路的配置方式必须要配备至少两个以上的水泵才能够保证整个系统的正常运行。这无疑会给生产者带来设备投资压力。同时，冷水机在利用变流量冷冻水的过程当中的工作效率也会受到冷冻水送水以及回水混合状态的影响。不仪如此，在实际情况中空渊需要进行高负荷的运行的时候会与最大的工况设计系统会产生摩擦致使冷水机的整个负荷所能承载的容量得不到充分有效地利用。囚此，如果婴恕以上的这些可能存缸的问题不会发生，就可以适时地考虑单环路的空捌冷冻水系统。笔者将重点阐述和分析以单环路为配置方式的变流量系统枉空凋冷冻水系统中的优势，并什测在实际使用过程中会产生的问题以及捉出安全可靠的控制方法。     

超快冷冻胚胎移植试管婴儿诞生

据新华社报道 ,由湖南医科大学人类生殖工程研究室实施的我国首例超快速冷冻胚胎移植的试管婴儿 3月 17日在长沙顺利诞生 ,运用这一方法接受试管婴儿手术的不孕症患者今年37岁 ,去年 7月接受快速冷冻胚胎移植。专家认为 ,该超快速冷冻胚胎移植试管婴儿的诞生 ,为用此法取代慢速冷冻法的胚胎冷冻保存技术打下了基础超快冷冻胚胎移植试管婴儿诞生@范锦姬     

Attachment kinetics, proliferation rates and vinculin assembly of bovine osteoblasts cultured on different pre-coated artificial substrates

Primary bovine osteoblasts were used to study in-vitro effects of attachment on vinculin assembly in cells cultured on various artificial substrates. Materials coated with fibronectin and bovine serum albumin (BSA) as well as untreated materials (tissue culture polystyrene and Aclar foils) were chosen to investigate substrate-dependent proliferation during the first 3 days of culture. Proliferation was highest on fibronectin-coated substrates, followed by BSA-coated and untreated substrates. During the first 24 h of cultivation, cell attachment kinetics revealed no significant difference between the various substrates. After 24 h detachment rates obtained by calcium depletion with ethylenediaminetetraacetic acid were highest on uncoated materials, followed by BSA- and fibronectin-coated substrates. Phase contrast microscopy revealed typical osteoblast morphology after cell adhesion for 24 h. The dynamic attachment process was concomitant with the reassembly of vinculin into streak-like focal contacts clustered on the ventral side of cells. The kinetics of vinculin reassembly were independent of the underlying coating. Thus, fibronectin coating of artificial substrates increased the attachment strength and proliferation rate of osteoblasts. While the reassembly of vinculin in focal contacts seems to be a prerequisite of osteoblast attachment in vitro, it does not seem to have profound effects on the subsequent cell behaviour on artificial substrates. © Chapman & Hall     

Evaluation of a Microreservoir-Type Biodegradable Microcapsule for Controlled Release of Proteins

For the controlled release of a model protein bovine serum albumin, a biodegradable microreservoir-type microcapsule was prepared. BSA was incorporated into the microcapsules with high efficiency of 96.1 (±3.1)%. The encapsulation did not cause any changes in the molecular weight and conformation of BSA, which was proven by biochemical analyses such as gel electrophoresis, circular dichroism, and HPLC.

The compositions and fabrication technique of microcapsules were found to be closely related to the release of BSA from the microcapsules and their degradation. Depending on microcapsule formulations, the in vitro release profile of BSA was either monophasic or biphasic. The microcapsules provided various release rates. It was also possible to control the delay before the initiation of BSA release and total duration of its delivery.     

半滑舌鳎肝脏细胞系的建立与鉴定

以半滑舌鳎肝脏组织为材料,探索了组织细胞分离培养条件,建立了半滑舌鳎组织细胞培养技术及半滑舌鳎肝脏细胞系（HTLC）。该细胞系的培养基是添加了抗生素、胎牛血清（FBS）、花鲈血清（SPS）、成纤维生长因子（bFGF）的MEM。HTLC形态呈纤维状,在培养基中生长迅速,经200多天的培养,成功传代30多代。检测了温度、FBS浓度、bFGF对其生长的影响,结果表明,在24～30℃生长良好,但当温度低于12℃时细胞生长速度明显减慢;在一定浓度范围内,其生长速度随血清浓度的升高而增快,血清浓度过高或过低对其生长不利;在培养基中添加bFGF可以使细胞生长速度显著提高;其二倍体核型为2n=21t。将绿色荧光蛋白（GFP）报告基因通过脂质体介导的方法转入HTLC中并成功地获得了表达,转化率为20％左右。该细胞系的建立为研究鱼类病毒学、免疫学、遗传学、功能基因组学提供了很好的实验材料。     

Evaluation of a Microreservoir-Type Biodegradable Microcapsule for Controlled Release of Proteins

Abstract

For the controlled release of a model protein bovine serum albumin, a biodegradable microreservoir-type microcapsule was prepared. BSA was incorporated into the microcapsules with high efficiency of 96.1 (±3.1)%. The encapsulation did not cause any changes in the molecular weight and conformation of BSA, which was proven by biochemical analyses such as gel electrophoresis, circular dichroism, and HPLC.

The compositions and fabrication technique of microcapsules were found to be closely related to the release of BSA from the microcapsules and their degradation. Depending on microcapsule formulations, the in vitro release profile of BSA was either monophasic or biphasic. The microcapsules provided various release rates. It was also possible to control the delay before the initiation of BSA release and total duration of its delivery.     

Oxygen consumption of single bovine embryos probed by scanning electrochemical microscopy

Oxygen consumption of individual bovine embryos was noninvasively quantified by scanning electrochemical microscopy (SECM). A probe microelectrode was used to scan near a single embryo surface in a culture medium to monitor the oxygen reduction current at 37 degrees C, under a water-saturated atmosphere of 5% CO2 and 95% air. The oxygen concentration profiles near the embryos were in good agreement with the theoretical spherical diffusion. When an embryo reached the stage of a morula with a 74-microm radius on day 6 after in vitro fertilization, the oxygen concentration difference (deltaC) between the bulk solution and the morula surface was 6.90 +/- 1.35 microM. The oxygen consumption rate (F) of the single morula was estimated to be (1.40 +/- 0.27) x 10(-14) mol s(-1). After the SECM measurement, the embryo was continuously cultured for another 2 days and grew to the stage of a blastocyst with a 100-microm radius. For the blastocyst, the deltaC values for the inner cell mass side and the trophoblast side were 16.40 +/- 1.83 and 9.14 +/- 1.68 microM, respectively. The oxygen consumption rate of the blastocyst was found to be in the range of (2.50 +/- 0.46) x 10(-14) mol s(-1) < F < (4.49 +/- 0.50) x 10(-14) mol s(-1). We have carried out SECM measurements for 19 embryos, and the results were compared in detail with these from an optical microscopic observation. The deltaC values for the morulae on day 6 after in vitro fertilization were strongly related to the morphological embryo quality. The morulae showing a larger deltaC value developed into blastocysts of a larger size, and the deltaC value after the subsequent 2 days of cultivation was found to be increased.     

Fabrication of a PLGA-collagen peripheral nerve scaffold and investigation of its sustained release property in vitro

This study deals with the fabrication of a peripheral nerve scaffold prepared with poly (lactic acid -co- glycolic acid) [PLGA] and acellularized pigskin collagen micro particles and the investigation of its sustained release property in vitro. We took bovine serum albumin [BSA] as model drug to investigate the sustained-release property of the scaffold in vitro. The results showed the scaffold could release BSA steadily with a rate of 6.6 ng/d (r = 0.994) or so. In a 1-month test period, the accumulative release ratio of BSA from the scaffold was up to 43%, and the shape of the scaffold was still originally well kept. In addition, the scaffold outcome non-immunogenicity, good cell adhesion and biodegradability. The results indicated a scaffold constructed by this technique would be a potential implanting support with prolonged sustained release function, such as for the use of nerve scaffold.     

Multifunctional nanofibrous scaffold for tissue engineering

In tissue engineering, scaffolds with multiscale functionality, especially with the ability to release locally multiple or specific bioactive molecules to targeted cell types, are highly desired in regulating appropriate cell phenotypes. In this study, poly (epsilon-caprolactone) (PCL) solutions (8% w/v) containing different amounts of bovine serum albumin (BSA) with or without collagen were electrospun into nanofibres. As verified by protein release assay and fluorescent labelling, BSA and collagen were successfully incorporated into electrospun nanofibres. The biological activity of functionalised fibres was proven in the cell culture experiments using human dermal fibroblasts. By controlling the sequential deposition and fibre alignment, 3D scaffolds with spatial distribution of collagen or BSA were assembled using fluorescently labelled nanofibres. Human dermal fibroblasts showed preferential adhesion to PCL nanofibres containing collagen than PCL alone. Taken together, multiscale scaffolds with diverse functionality and tunable distribution of biomolecules across the nanofibrous scaffold can be fabricated using electrospun nanofibres.     

磺化氧化石墨烯/聚砜复合膜的制备及抗污染性能

采用浸没沉淀-相转化法制备了磺化氧化石墨烯/聚砜（SGO/PSf）复合膜,对SGO/PSf复合膜的亲水性、纯水通量、孔隙率、表面Zeta电位、膜断面和表面形貌进行测定。为了分析SGO/PSf复合膜的抗污染性能,采用自制牛血清白蛋白（BSA）探针,借助原子力显微镜（AFM）测定了SGO/PSf复合膜与BSA之间的黏附力。结果表明,由于SGO与聚乙烯吡咯烷酮（PVP）的协同作用,SGO含量为0.5wt%的SGO/PSf复合膜的表面自由能最大（114.47 mJ/m2）,亲水性最好,对BSA的截留率为97.5%,污染恢复率达到80.06%。BSA与SGO含量为0.5wt%的SGO/PSf复合膜之间的黏附力最小（-0.61 mN/m）,说明SGO含量为0.5wt%的SGO/PSf复合膜的抗污染能力最强。      

BSA-PLGA微球的优化制备及特性

目的:优化BSA-PLGA微球制备工艺,并对其包封率、形态、体外释放药物及微球包裹前后BSA的稳定性进行评价。方法:以PLGA为载体,采用复乳溶剂挥发法制备BSA-PLGA微球。Micro BCA法测定微球的包封率和载药量,扫描电子显微镜观察微球的形态,激光粒度仪测定粒度及分布,聚丙烯酰胺凝胶电泳(SDS-PAGE)研究微球包裹前后BSA分子结构的完整性,同时考察体外释药性能。结果:根据优化工艺制备的微球外观圆整,平均粒径(2275.8±256.9)nm,包封率(82.59±2.92)%,载药量(13.76±0.49)×10-2%,包裹前后BSA结构稳定,体外释放28天以上,释放曲线符合Higuchi方程。结论:本研究获得了较优化的BSA-PLGA微球制备工艺,所制备的微球具有较高的包封率和明显的缓释效果。     

Preparation, structure and drug release behaviour of chitosan-based nanofibres

Biomimetic polymeric nanofibres are of great interest in tissue engineering and wound repair because of their structural similarity to extracellular matrix. In this work, biomimetic chitosan-based nanofibres with various diameters were prepared by ionically cross-linking with tripolyphosphate (TPP) in adipic acid medium and characterised using transmission electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. Using dexamethasone sodium phosphate (DMP) and bovine serum albumin (BSA) as low and high molecular-weight bioactive molecule models, respectively, drug loading and in vitro release behaviours of chitosan-TPP nanofibres were investigated. The drug-loaded chitosan-TPP nanofibres showed a prolonged release profile with three distinct stages in physiological conditions because of the complicated release mechanisms involving diffusion of the drug and degradation of the nanofibre, and BSA-loaded nanofibres showed a smaller release rate than DMP-loaded nanofibres. It is proposed that biomimetic chitosan-based nanofibres may be of use in tissue engineering for sustained release of bioactive agents.