Effects of Dragonfly Wing Structure on the Dynamic Performances

The configurations of dragonfly wings, including the corrugations of the chordwise cross-section, the microstructure of the longitudinal veins and membrane, were comprehensively investigated using the Environmental Scanning Electron Microscopy (ESEM). Based on the experimental results reported previously, the multi-scale and multi-dimensional models with different structural features of dragonfly wing were created, and the biological dynamic behaviors of wing models were discussed through the Finite Element Method (FEM). The results demonstrate that the effects of different structural features on dynamic behaviors of dragonfly wing such as natural frequency/modal, bending/torsional deformation, reaction force/torque are very significant. The corrugations of dragonfly wing along the chordwise can observably improve the flapping frequency because of the greater structural stiffness of wings. In updated model, the novel sandwich microstructure of the longitudinal veins remarkably improves the torsional deformation of dragonfly wing while it has a little effect on the flapping frequency and bending deformation. These integrated structural features can adjust the deformation of wing oneself, therefore the flow field around the wings can be controlled adaptively. The fact is that the flights of dragonfly wing with sandwich microstructure of longitudinal veins are more efficient and intelligent.     

不同发育期诸氏鲻虾虎鱼对钻井液的敏感性比较

目的筛选试验鱼适宜急性毒性试验的发育期。方法将诸氏鲻虾虎鱼早期仔鱼、中期仔鱼、晚期仔鱼、稚鱼、幼鱼及成鱼暴露于一定浓度的钻井液中,比较钻井液对不同发育期诸氏鲻虾虎鱼的急性毒性。结果早期仔鱼48 h LC50为157 mg/L,中期仔鱼48 h LC50大于500 mg/L;中期仔鱼96 h LC50为79 mg/L,晚期仔鱼96h LC50为625 mg/L,稚鱼、幼鱼、成鱼96 h LC50显著大于500 mg/L;卤虫无节幼体96 h LC50为105 mg/L;不同发育期诸氏鲻虾虎鱼对钻井液的敏感性顺序为：早期仔鱼〉中期仔鱼〉晚期仔鱼〉稚、幼、成鱼。结论诸氏鲻虾虎鱼的早期仔鱼适用于海洋污染物急性毒性评价。     

激光诱变小麦后代材料籽粒贮藏蛋白编码基因变异的研究

本研究采用SDS—PAGE分析了冀麦七号、冀麦18和冀早15三个品种激光后代籽粒贮藏蛋白的变异情况。结果表明,高分子量麦谷蛋白和醇溶蛋白亚基变异较小,其控制位点为Glu—1和Gl—3或Gli—1;而低分子量部分变异较大,其控制位点多在Glu—3、Gli—2和Gli—3。这些变异具有一定的随机性。有关激光诱变对小麦面粉品质的影响有待进一步研究。     

马铃薯StPSKRs基因的克隆及其亚细胞定位分析

该研究采用同源克隆与PCR扩增方法,从马铃薯品种‘Desiree’中克隆植物磺肽素受体基因StPSKR1和StPSKR2的全长cDNA,并对其进行生物信息学分析及亚细胞定位分析,为深入研究StPSKR1和StPSKR2基因在马铃薯生长发育和生物胁迫中的作用提供理论依据。结果发现:(1)通过同源克隆与PCR扩增获得StPSKR1和StPSKR2的全长cDNA片段,并将其克隆到pGWB5-GFP载体;测序结果显示这2个基因编码的蛋白质与数据库给定的蛋白质序列保持一致,表明成功克隆到StPSKR1和StPSKR2基因。(2)StPSKR1位于马铃薯1号染色体上,cDNA全长3 042 bp,编码1 013个氨基酸,预测蛋白相对分子质量为112.16 kD,理论等电点6.27;StPSKR2位于7号染色体,cDNA全长3 135 bp,编码1 044个氨基酸,相对分子量为114.99 kD,理论等电点6.19。(3)生物信息学分析显示,StPSKR1和StPSKR2都属于跨膜蛋白。(4)亚细胞定位结果显示,StPSKR1和StPSKR2均定位于细胞膜上。     

Purification and characterization of high antioxidant peptides from duck egg white protein hydrolysates

The hydrolysate from duck egg white protein (DEWP) prepared by “SEEP–Alcalase” at degree of hydrolysis (DH) value of 21% (namely HSA₂₁) exhibited high antioxidant capacity in different oxidation systems. A consecutive chromatographic method was then developed for separation and purification of HSA₂₁, including ion-exchange chromatography, macroporous adsorption resin (MAR) and gel filter chromatography. The final peptides “P_21-3–75-B” were obtained with significantly enhanced antioxidant activity (p < 0.05). It was further confirmed that the product mainly consisted of five oligopeptides (Mr: 202.1, 294.1, 382.1, 426.3, and 514.4 Da). Furthermore, the antioxidant activity of P_21-3–75-B kept stable after in vitro digestive simulation. Antioxidant capacity of the purified peptides was closely related to the molecular mass, hydrophobic amino acid residues, acidic amino acid and some antioxidant amino acids. This research provided a valuable route for producing new natural-source peptides with strong antioxidant capacity and high nutritious value for our daily intake.     

Mn/Fe superoxide dismutase interaction fingerprints and prediction of oligomerization and metal cofactor from sequence

Fe- and Mn-containing superoxide dismutase (sod) enzymes are closely related and similar in both amino acid sequence and structure, but differ in their mode of oligomerization and in their specificity for the Fe or Mn cofactor. The goal of the present work is to identify and analyze the sequence and structure characteristics that ensure the cofactor specificities and the oligomerization modes. For that purpose, 374 sod sequences and 17 sod crystal structures were collected and aligned. These alignments were searched for residues and inter-residue interactions that are conserved within the whole sod family, or alternatively, that are specific to a given sod subfamily sharing common characteristics. This led us to define key residues and inter-residue interaction fingerprints in each subfamily. The comparison of these fingerprints allows, on a rational basis, the design of mutants likely to modulate the activity and/or specificity of the target sod, in good agreement with the available experimental results on known mutants. The key residues and interaction fingerprints are furthermore used to predict if a novel sequence corresponds to a sod enzyme, and if so, what type of sod it is. The predictions of this fingerprint method reach much higher scores and present much more discriminative power than the commonly used method that uses pairwise sequence comparisons.     

Kisspeptins在孕早期血浆和胎盘组织中的表达及其意义

目的:研究kisspeptins在孕早期血浆和胎盘组织中的表达,拟探讨其来源及其在妊娠中意义.方法:采用酶联免疫吸附法(ELISA),检测40例孕早期妇女和35例正常未妊娠妇女血浆kisspeptins的表达水平,且分析其与hCG的相关性;采用免疫组织化学方法进行其组织学定位.结果:(1)kisspeptins在妊娠组...     

噬菌体抗体文库的构建及人源抗HIV-1 gp 160抗体的筛选

构建人源噬菌体抗体文库如下：ＨＩＶ感染者脾细胞中提取ｍＲＮＡ,经反转录再以人ＩｇＧ重链Ｆｄ两端及轻链“通用”引物分别扩增Ｆａｂ基因片段,依次插入到噬菌粒载体ｐＣｏｍｂ３中,电转化大肠杆菌ＸＬ１－Ｂｌｕｅ,经辅助噬菌体救助,重组噬菌体得以溶源裂解,Ｆａｂ表达于噬菌体包膜蛋白Ⅲ的Ｎ端．此噬菌体抗体库的容量为５×１０５．筛选抗ＨＩＶ－１同时又具有能被抗独特型抗体“ＩＦ７”所识别的独特型的阳性抗体：以重组包膜糖蛋白ｇｐ１６０及ｇｐ４１多肽对噬菌体抗体文库进行三次淘选,使抗ｇｐ１６０的特异性抗体得到１００倍的富集．然后通过直接ＥＬＩＳＡ和竞争性ＥＬＩＳＡ实验筛选出两株结合性较好的特异性抗ｇｐ１６０抗体－３Ｂ株与１Ｄ株．直接ＥＬＩＳＡ实验表明这两株克隆均能被“１Ｆ７”所识别,为抗独特型多肽的筛选奠定了基础．     

Biocathode microbial fuel cell for efficient electricity recovery from dairy manure

Microbial fuel cells (MFCs) represent a new biological method for generating electricity directly from biodegradable compounds. Efficiency of MFCs using manure as substrate is generally low. This study proposed a new design by incorporating biocathodes into a three-chamber MFC, which yielded maximum power densities much higher than those reported in literature. The new design placed cylindrical anode chamber for easy stirring and two symmetrical cathodic chambers with reduced anode-cathode distance. The biocathodes were applied to reduce charge transfer resistance. Additionally, biocathode microbial community was cultured to enrich favorable microorganisms. With external loading of 100 Ω, the power densities for new biocathode MFC using 2, 4, 6, 8 and 10% total solids diary manure reached 7.85±1.0 W m(-3), 7.84±1.20 W m(-3), 8.15±0.20 W m(-3), 7.60±0.97 W m(-3) and 5.63±0.97 W m(-3), respectively. The pH drop as a result of manure hydrolysis limited the power output. To provide detailed information of the microbial community in the biocathode MFC, the 454-pyrosequencing technique was adopted. The Firmicutes, γ-, β-, α- and δ-Proteobacteria, Bacteroidetes and Actinobacteria were the major groups on the anode, while γ-, β-, and α-Proteobacteria, Bacteroidetes and Actinobacteria were the predominant groups on the cathode.