人USP14蛋白在大肠杆菌中表达纯化的初步研究

采用PCR技术从人胎脑cDNA文库中克隆了usp14(ubiquitin-specific peptidase 14)基因编码区全长序列。序列分析表明人usp14基因含有peptidase蛋白酶C19A保守区,将usp14基因与pET-28b(+)载体相连,构建表达载体pET28b/usp14;把该表达载体转入大肠杆菌Rosetta(DE3)pLyS,以Isopropyl-D-thiogalactopyranoside(IPTG)诱导25°C 6小时,USP14蛋白获得高效表达。对表达产物进行Western blotting检测,并用Ni-NTA亲和层析技术获得了纯化的人USP14蛋白,表达的目的蛋白大小约为56kDa。     

汞对小麦幼苗损伤机制研究

本文研究汞对小麦种子萌发过程中幼苗膜脂过氧化水平，细胞膜透性，保护酶（CAT、SOD、POD)活性，可溶性糖和可溶性蛋白质含量的影响．结果表明，随着汞浓度的升高，细胞膜脂质过氧化水平升高．细胞膜透性增大，CAT活性降低、POD、SOD活性升高，组织可溶性糖和可溶性蛋白质含量升高．     

肠道机器人无线电能传输装置的研制

无线供能技术的突破促进了医疗、军事、航空航天、便携式通信设备等领域的发展.本文通过运用电磁感应原理,设计了基于ICPT无线供能技术的肠道机器人无线电能传输装置.通过智能感应终端与充电线圈的耦合,自动校准线圈位置,提高了无线电能传输的效率,最终实现了对肠道机器人的高效无线充电.由于可以对肠道机器人进行无线充电,肠道机器人自身携带电池容量可减小到原来的三分之一,肠道机器人体积相应缩小,减小了由于机器人体积过大对肠道造成的损伤,增加了安全性,此充电方法可以保证肠道机器人作业电能需求.本文还证明了运用电磁感应原理无线传能的可行性、列举了此方法在其它领域的典型应用.     

仁扇舟蛾幼虫肠道可培养细菌群落结构分析

[目的]了解仁扇舟蛾(Clostera restitura)肠道共生细菌的主要类群及其群落结构特征,明确仁扇舟蛾幼虫前、中和后肠可培养细菌的种类及群落结构组成,为进一步研究特异功能细菌的生理生化特征和功能提供基础.[方法]选取仁扇舟蛾5龄幼虫进行肠道解剖,分离前、中和后肠不同肠段,研磨稀释10-1～10-6,分别涂布于...     

温度和pH对驼背鲈消化酶活力的影响

采用酶学分析方法研究了温度和pH对驼背鲈3种主要消化酶(蛋白酶、脂肪酶、淀粉酶)活力的影响。结果表明:在设定的温度和pH范围内,驼背鲈消化酶活力均随着温度和pH的升高呈先升后降的趋势。其中,胃蛋白酶的最适温度为40~45℃,肠、幽门盲囊、肝蛋白酶的最适温度均为40℃;胃脂肪酶的最适温度为35℃,幽门盲囊的最适温度为40~45℃,其他部位均为40℃;胃淀粉酶的最适温度为40℃,其他部位均为35℃。胃蛋白酶的最适pH为3.2,肠、幽门盲囊、肝的最适pH均为8.2;胃、肝脂肪酶的最适pH分别为7.2、8.2,其他部位均为6.2;胃淀粉酶的最适pH为7.2~8.2,其他器官的最适pH均为7.2。各部位在最适温度和pH下,脂肪酶酶活力顺序为肠胃肝幽门盲囊,淀粉酶酶活力顺序为肠幽门盲囊胃肝;蛋白酶在最适温度和pH下的酶活力顺序分别为肠胃肝幽门盲囊、肠胃幽门盲囊肝。     

肠道内窥镜活检机器人系统

基于肠道活检诊疗任务,设计了气囊钳位和活检机构,研制出肠道胶囊内窥镜机器人,完成了在肠道中的自主运动、视频检查和活检取样任务,并通过实验检测了肠道活检机器人系统的性能.结果表明:采用花瓣气囊能够减小容积,缩短打气时间,并使钳位力提高至1.56N;所用活检钳的剪切力大于10N,且活检过程可视、动作可重复;在无线供能条件下,所研制的系统运行稳定.     

Precursors to regulatory peptides: their proteolytic processing

Summary Precursors to regulatory peptides undergo maturation processes which include protelytic processing. The enzymes involved in this process remove the hydrophobic peptide located at the amino-terminus of the precursor. Endoprotease cleavage also occurs at single and two adjacent basic residues, this is followed by a removal of basic residues located at the C-terminus of the peptides by a carboxypeptidase-like enzyme.     

Hummingbird flight: Sustaining the highest mass-specific metabolic rates among vertebrates

Resting and maximal mass-specific metabolic rates scale inversely with body mass. Small hummingbirds achieve the highest known mass-specific metabolic rates among vertebrate homeotherms. Maximal capacities for O₂ and substrate delivery to muscle mitochondria, as well as mitochondrial oxidative capacities in these animals may be at the upper limits of what are structurally and functionally possible given the constraints inherent in vertebrate design. Such constraints on the evolutionary design of functional capacities may play an important role in determining the lower limits to vertebrate homeotherm size and the upper limits to mass-specific metabolic rate.     

Debriding ability of a novel multi-enzyme preparation isolated from Antarctic krill (Euphausia superba)

Summary The wound-debriding activity of various types of proteolytic enzymes and proteases from Antarctic krill (multi-enzyme system consisting of both endo- and exopeptidases) was evaluated. The results, based on the enzymatically acieved weight reduction of a necrotic animal material (excised rat skin) in vitro, clearly showed that the multi-enzyme system (krill) had a higher degrading activity than the single enzyme preparation, or that with only a few enzymes. The debriding effect of the krill enzymes was markedly related to the enzyme concentration, resulting in 70–100% substrate degradation after 24 h. The digesting capacity of trypsin reached about 50%, but an increase in concentration of this enzyme did not substantially influence its overall activity. The effect of streptokinase-streptodornase, collagenase and plasmin-desoxyribonuclease was weak (10–20% digested).     

Plasma and hepatic antioxidant control and vitamin A nutritional status

Twenty-seven rats were divided into three groups and fed on diets containing 0.3, 6 or 60 RE (retinol equivalent) retinyl palmitate/g food. After 7 weeks, hepatic vitamin A uptake was found to be more efficient in vitamin A-deficient rats than in rats given adequate vitamin A. We showed that during the metabolic adaptation of the animals to the level of vitamin A in the diet, extensive modifications occur in the antioxidant defences of the organism. In parallel with the increase in the level of vitamin A, the decrease in the level of -tocopherol in the plasma can bring about a greater susceptibility of the lipoproteins to oxidative stress. Similarly, the decrease in the hepatic -tocopherol level and in glutathione peroxidase activity leads to the weakening of the liver's antioxidant defences.