大黄素对豚鼠结肠带平滑肌细胞电和收缩性能的影响

联合应用平滑肌肌力张力测量技术和细胞内微电极记录技术,同步地现测豚鼠结肠带平滑肌自发的肌源性电活动和力学活动,研究了大黄素的药物作用。大黄素能缩短膜电位的波动周期,从而缩短峰电位集簇发放的周期;相应地,可使平滑肌的分节律收缩加快,幅值指数升高。大黄素又能促使细胞膜电位自发的周期性波动的出现,导致峰电位的集簇发放;相应地,可使强直收缩转化为分节律收缩,即促进收缩形式向有利于肠道推进功能的方向转化。以上结果表明,大黄素能有效地提高豚鼠结肠带平滑肌细胞的电兴奋性和收缩功能,并且对其电学和力学活动的影响之间有明确的对应关系。     

新疆野核桃自然保护区不同坡向丛生野核桃年龄结构及数量动态

通过对新疆野核桃自然保护区丛生野核桃(Juglans regia)进行普查,以径级结构代替年龄结构,采用匀滑技术编制种群静态生命表,并运用时间序列模型预测种群数量动态,从而获得丛生野核桃树的龄级结构与动态。结果表明,不同坡向丛生野核桃以中龄级为主,年龄结构呈两头小中间大的纺锤型;4个坡向种群年龄结构的动态指数Vpi虽大于0,但最大仅为19.10%,且Vpi’极低,最大为1.12%,阳坡种群增长趋势最高,抗干扰能力最强,种群稳定性最好,半阳坡种群增长趋势最弱,抗干扰能力最弱,种群稳定性最差;各坡向种群均存在多个死亡高峰,阳坡最高峰在15龄级,半阳坡在15和18龄级,阴坡和半阴坡均在9龄级,存活曲线更接近Deevey-Ⅱ型;在未来2、5、10龄级后,中龄级个体数量减少,老龄个体呈增加趋势,丛生野核桃种群稳定性难以长期维持。因此对丛生野核桃幼苗的保护非常关键。     

Genetic basis of kernel nutritional traits during maize domestication and improvement

The nutritional traits of maize kernels are important for human and animal nutrition, and these traits have undergone selection to meet the diverse nutritional needs of humans. However, our knowledge of the genetic basis of selecting for kernel nutritional traits is limited. Here, we identified both single and epistatic quantitative trait loci (QTLs) that contributed to the differences of oil and carotenoid traits between maize and teosinte. Over half of teosinte alleles of single QTLs increased the values of the detected oil and carotenoid traits. Based on the pleiotropism or linkage information of the identified single QTLs, we constructed a trait–locus network to help clarify the genetic basis of correlations among oil and carotenoid traits. Furthermore, the selection features and evolutionary trajectories of the genes or loci underlying variations in oil and carotenoid traits revealed that these nutritional traits produced diverse selection events during maize domestication and improvement. To illustrate more, a mutator distance–relative transposable element (TE) in intron 1 of DXS2, which encoded a rate‐limiting enzyme in the methylerythritol phosphate pathway, was identified to increase carotenoid biosynthesis by enhancing DXS2 expression. This TE occurs in the grass teosinte, and has been found to have undergone selection during maize domestication and improvement, and is almost fixed in yellow maize. Our findings not only provide important insights into evolutionary changes in nutritional traits, but also highlight the feasibility of reintroducing back into commercial agricultural germplasm those nutritionally important genes hidden in wild relatives.     

马蔺IlWRKY28基因的克隆与表达分析

马蔺(Iris lactea var. chinensis)是鸢尾属多年生草本盐生植物,具有很高的耐盐性和观赏价值。为研究马蔺耐盐的分子机制,通过cDNA末端快速扩增技术(RACE)从马蔺中克隆到一个WRKY转录因子基因IlWRKY28,获得了1 302 bp的全长cDNA序列,其包含一个108 bp 5′末端非翻译区(UTR),一个174 bp 3′末端UTR和一个1 020 bp开放阅读框。IlWRKY28编码339个氨基酸,预测的蛋白质分子量为37.22 kD,等电点为7.04。氨基酸序列分析显示,IlWRKY28包含一个保守的WRKY基序和一个C2H2型锌指结构域。系统发育分析表明,马蔺IlWRKY28与菠萝(Ananas comosus)AcWRKY28和藏北嵩草(Kobresia littledalei)ClWRKY28亲缘关系最近。荧光定量PCR分析显示,盐处理后,IlWRKY28基因在马蔺地上部显著上调表达。该研究结果为进一步研究IlWRKY28在马蔺适应高盐胁迫中的功能和作用机制奠定了重要的分子基础。     

微生物技术治理水体重金属镉、铬污染的研究进展

近年来,随着我国工农业迅速发展,"三废"的大量排放,水体中重金属污染愈发严重,其中重金属镉、铬的污染显得尤为突出。研究者利用微生物技术开展了大量治理污水中镉、铬的研究。本文就不同种类微生物对镉、铬的修复及作用机理进行论述,以期为微生物用于实际污水中镉、铬的治理提供参考。     

马氏珠母贝Caspase-3基因克隆和组织表达分析

半胱氨酸蛋白酶3 (Caspase-3)作为细胞凋亡通路中重要的效应蛋白,在细胞凋亡过程中发挥着重要作用.为初步探究马氏珠母贝Caspase-3(PmCaspase-3)的生物学功能,本研究利用cDNA末端快速扩增(RACE)技术克隆获得PmCaspase-3基因cDNA的全长序列并对其序列特征进行分析;同时利用实时荧光定量PCR (RT-qPCR)方法分析了PmCaspase-3基因mRNA在马氏珠母贝不同组织和不同发育时期的表达差异.结果 显示,PmCaspase-3基因cDNA全长为2233 bp,其中5'端非编码区长度为80 bp,3'端非编码长度为31 bp,开放阅读框长度为2088 bp,共编码695个氨基酸;生物信息学分析显示,PmCaspase-3含有Caspase家族特有的CASc结构域和半胱氨酸蛋白酶家族p20、p10活性位点以及多种磷酸化位点,经进化分析以及多序列比对可知与其他物种Caspase-3蛋白同源性较高.RT-qPCR结果表明,PmCaspase-3在肝胰腺中的表达量最高,在闭壳肌中的表达量最低;在发育过程中D型幼虫期和眼点期的表达量较高.     

Integrating domain similarity to improve protein complexes identification in TAP-MS data

Background

Detecting protein complexes in protein-protein interaction (PPI) networks plays an important role in improving our understanding of the dynamic of cellular organisation. However, protein interaction data generated by high-throughput experiments such as yeast-two-hybrid (Y2H) and tandem affinity-purification/mass-spectrometry (TAP-MS) are characterised by the presence of a significant number of false positives and false negatives. In recent years there has been a growing trend to incorporate diverse domain knowledge to support large-scale analysis of PPI networks.

Methods

This paper presents a new algorithm, by incorporating Gene Ontology (GO) based semantic similarities, to detect protein complexes from PPI networks generated by TAP-MS. By taking co-complex relations in TAP-MS data into account, TAP-MS PPI networks are modelled as bipartite graph, where bait proteins consist of one set of nodes and prey proteins are on the other. Similarities between pairs of bait proteins are computed by considering both the topological features and GO-driven semantic similarities. Bait proteins are then grouped in to sets of clusters based on their pair-wise similarities to produce a set of 'seed' clusters. An expansion process is applied to each 'seed' cluster to recruit prey proteins which are significantly associated with the same set of bait proteins. Thus, completely identified protein complexes are then obtained.

Results

The proposed algorithm has been applied to real TAP-MS PPI networks. Fifteen quality measures have been employed to evaluate the quality of generated protein complexes. Experimental results show that the proposed algorithm has greatly improved the accuracy of identifying complexes and outperformed several state-of-the-art clustering algorithms. Moreover, by incorporating semantic similarity, the proposed algorithm is more robust to noises in the networks.

     

Serum Uric Acid and Non-Alcoholic Fatty Liver Disease in Non-Diabetic Chinese Men

Increased serum uric acid (SUA) levels may be involved in the development of non-alcoholic fatty liver disease (NAFLD) in men presenting with metabolic syndrome (MetS) and/or insulin resistance. We aimed to determine the independent relationship between SUA and NAFLD in non-diabetic Chinese male population, and to explore the determinants of SUA levels among indexes of adiposity, lipid, and genotypes pertaining to triglycerides metabolism, inflammation, oxidative stress, and SUA concentrations. A total of 1440 men, classified depending on the presence of ultrasonographically detected NAFLD, underwent a complete healthy checkup program. Genotypes were extracted from our previously established genome-wide association study database. After adjusting for age, smoking, drinking, body mass index, homeostasis model assessment of insulin resistance, C-reactive protein, creatinine, alanine aminotransferase (ALT) and components of metabolic syndrome, the odds ratio for NAFLD, comparing the highest with the lowest SUA quartile, was 2.81 (95% confidence interval 1.66–4.76). A stepwise multivariate linear regression analysis (R² = 0.238, P<0.001) retained age, waist circumference, serum creatinine, triglycerides, the Q141K variant in ABCG2 (rs2231142) and NAFLD as significant predictors of SUA levels (all P<0.001). Besides, ALT and Met196Arg variant in TNFRSF1B (rs1061622) additionally associated with SUA among individuls with NAFLD. Our data suggest that in Chinese men, elevated SUA is significantly associated with NAFLD, independent of insulin resistance and other metabolic disorders, such as central obesity or hypertriglyceridemia. Meanwhile, among subjects with NAFLD, index of liver damage, such as elevated ALT combined with genetic susceptibility to inflammation associated with increased SUA levels.     

Regeneration of Soft Tissues Is Promoted by MMP1 Treatment after Digit Amputation in Mice

The ratio of matrix metalloproteinases (MMPs) to the tissue inhibitors of metalloproteinases (TIMPs) in wounded tissues strictly control the protease activity of MMPs, and therefore regulate the progress of wound closure, tissue regeneration and scar formation. Some amphibians (i.e. axolotl/newt) demonstrate complete regeneration of missing or wounded digits and even limbs; MMPs play a critical role during amphibian regeneration. Conversely, mammalian wound healing re-establishes tissue integrity, but at the expense of scar tissue formation. The differences between amphibian regeneration and mammalian wound healing can be attributed to the greater ratio of MMPs to TIMPs in amphibian tissue. Previous studies have demonstrated the ability of MMP1 to effectively promote skeletal muscle regeneration by favoring extracellular matrix (ECM) remodeling to enhance cell proliferation and migration. In this study, MMP1 was administered to the digits amputated at the mid-second phalanx of adult mice to observe its effect on digit regeneration. Results indicated that the regeneration of soft tissue and the rate of wound closure were significantly improved by MMP1 administration, but the elongation of the skeletal tissue was insignificantly affected. During digit regeneration, more mutipotent progenitor cells, capillary vasculature and neuromuscular-related tissues were observed in MMP1 treated tissues; moreover, there was less fibrotic tissue formed in treated digits. In summary, MMP1 was found to be effective in promoting wound healing in amputated digits of adult mice.