Nonparametric disequilibrium mapping of functional sites using haplotypes of multiple tightly linked single-nucleotide polymorphism markers

As the speed and efficiency of genotyping single-nucleotide polymorphisms (SNPs) increase, using the SNP map, it becomes possible to evaluate the extent to which a common haplotype contributes to the risk of disease. In this study we propose a new procedure for mapping functional sites or regions of a candidate gene of interest using multiple linked SNPs. Based on a case-parent trio family design, we use expectation-maximization (EM) algorithm-derived haplotype frequency estimates of multiple tightly linked SNPs from both unambiguous and ambiguous families to construct a contingency statistic S for linkage disequilibrium (LD) analysis. In the procedure, a moving-window scan for functional SNP sites or regions can cover an unlimited number of loci except for the limitation of computer storage. Within a window, all possible widths of haplotypes are utilized to find the maximum statistic S* for each site (or locus). Furthermore, this method can be applied to regional or genome-wide scanning for determining linkage disequilibrium using SNPs. The sensitivity of the proposed procedure was examined on the simulated data set from the Genetic Analysis Workshop (GAW) 12. Compared with the conventional and generalized TDT methods, our procedure is more flexible and powerful.     

PCR检测伪狂犬病病毒DNA

 根据伪狂犬病病毒 (PRV)gB基因的序列 ,设计并合成了一对引物 ,以闽A株细胞培养毒为模板 ,筛选最佳反应条件 ,建立了检测PRV的PCR方法 应用该方法对Fb、Bartha、BJ、GD、V2F4、S、S3、SR、Buk、Shope、Norden、MinkⅢ、HB、F8、F9、F12等毒株的细胞培养液进行基因扩增 ,均获得了分子量为 2 81bp的特异性目的DNA片段 ,而对Vero细胞与FMDV、SVDV、HCV、PRRSV、JEV、PPV等病毒进行检测 ,结果均为阴性 ,没有出现交叉反应 对PRV毒株扩增的产物测序 ,结果序列与文献报道一致 ,证明PCR扩增产物和方法的特异性 对 1994～ 2 0 0 0年期间送检的临床样品和保存的PRV毒种 ,用病毒分离、双抗体夹心ELISA和PCR等 3种方法进行检测 ,结果前 2种方法检测为阳性的 ,PCR检测均为阳性 ;PCR检测为阴性 ,前 2种方法检测也为阴性 ;可是 ,前 2种方法检测为阴性的 ,PCR却检测出部分阳性 ;经x2 检验 ,证明PCR检出率明显高于前 2种方法的检出率 对PRV闽A株细胞毒提取物DNA进行检测 ,其最低检出量为 15 8pg 对 1999～ 2 0 0 0年期间广东、福建、海南等省的 31个大中型猪场送检的 191份病料进行检测 .结果病料阳性率为 2 6 2 % ( 50 191) ,猪场阳性率为 71% ( 2 2 31) 实验结果表明 ,所建立的PCR技术可用于伪狂犬病的快速诊断     

小鼠2-细胞胚胎单个卵裂球体外培养及其发育形成囊胚的玻璃化冷冻保存技术的研究

单个卵裂球分离和培养是生产同卵双胎或一卵多胎动物的一种有效方法。在羊和牛已经获得了来源于2-细胞和4-细胞期胚胎的单个卵裂球的活体后代;在兔也获得来源于4-细胞胚胎的单个卵裂球后代;在猪已获得8-细胞单个卵裂球的后代。但多数的研究者发现,小鼠单个卵裂球培养后的体外发育率、移植妊娠率和产仔率都很低。上述均为新鲜胚移植结果,至于分离后卵裂球发育成的囊胚再进行玻璃化冷冻保存尚未见报道。本实     

Optimization of fermentation conditions for preparation of polygalacturonic acid transeliminase by Erwinia carotovora IFO3830

This paper is concerned with optimization of the fermentation conditions for preparation of alkaline pectin lyase (poly-galacturonic acid trans-eliminase, PATE) by Erwinia carotovora IFO3830 (E.C.IFO3830). The orthogonal matrix method was adopted as the experimental design method for media. The effects of media composition on the growth rate of E.C.IFO3830 are in the order of pectin > KH(2)PO(4)/Na(2)HPO(4) > MgSO(4) > (NH(4))(2)SO(4) > glucose > L-glutamate sodium, and those on PATE activity are in the order of glucose > pectin > L-glutamate sodium > KH(2)PO(4)/Na(2)HPO(4) > MgSO(4) > (NH(4))(2)SO(4). The strain of E.C.IFO3830 grows quickly and easily near an initial pH of 7.0, and especially at the alkaline range of pH 7.0-8.0. The growth rate profiles indicate that E.C.IFO3830 grows very quickly; its generation time t(1/2) is about 0.2 h. The appropriate fermentation period is about 10-20 h for a high level productivity of biomass and 25-35 h for high productivity of PATE enzyme.     

免疫细胞与炎症介质在肠炎发病中的作用

肠炎的起因是多样的,但引起粘膜的损伤而出现各种临床症状的机制却是相似的。近年来免疫生物学,分子免疫学的发展对肠道粘膜免疫功能的了解有了巨大的进步。肠炎的起因是病原或过敏原刺激活化了先天免疫和特异免疫系统的细胞,由肠道上皮细胞、巨噬细胞和淋巴细胞分泌多种细胞因子,这些细胞因子再活化或动员更多的细胞,并进一步分泌更多的因子,形成病原、细胞和因子之间的级联反应。由细胞与因子的综合作用,造成肠道局部的炎症。炎症因子和抗炎因子比例的消长决定了炎症的转归和预后。对炎症因子及其拮抗剂作用机制的了解,将有助于肠炎的诊断和治疗。     

The suppressor of transgene RNA silencing encoded by Cucumber mosaic virus interferes with salicylic acid-mediated virus resistance

The Cucumber mosaic virus (CMV)-encoded 2b protein (Cmv2b) is a nuclear protein that suppresses transgene RNA silencing in Nicotiana benthamiana. Cmv2b is an important virulence determinant but nonessential for systemic spread in N. glutinosa, in contrast to its indispensable role for systemic infections in cucumber. Here, we report that Cmv2b became essential for systemic infections in older N. glutinosa plants or in young seedlings pretreated with salicylic acid (SA). Expression of Cmv2b from the genome of either CMV or Tobacco mosaic virus significantly reduced the inhibitory effect of SA on virus accumulation in inoculated leaves and systemic leaves. A close correlation is demonstrated between Cmv2b expression and a reduced SA-dependent induction of the alternative oxidase gene, a component of the recently proposed SA-regulated antiviral defense. These results collectively reveal a novel activity of Cmv2b in the inhibition of SA-mediated virus resistance. We used a N. tabacum line expressing a bacterial nahG transgene that degrades SA to provide evidence for a Cmv2b-sensitive antiviral defense mechanism in tobacco in which SA acts as a positive modifier but not as an essential component. We propose that SA induces virus resistance by potentiating a RNA-silencing antiviral defense that is targeted by Cmv2b.     

Antihypertensive effect of mechanism-based inhibition of renal arachidonic acid omega-hydroxylase activity

The cytochrome P-450 eicosanoid 20-hydroxyeicosatetraenoic acid (20-HETE) is a potent vasoconstrictor that is implicated in the regulation of blood pressure. The identification of selective inhibitors of renal 20-HETE formation for use in vivo would facilitate studies to determine the systemic effects of this eicosanoid. We characterized the acetylenic fatty acid sodium 10-undecynyl sulfate (10-SUYS) as a potent and selective mechanism-based inhibitor of renal 20-HETE formation. A single dose of 10-SUYS caused an acute reduction in mean arterial blood pressure in 8-wk-old spontaneously hypertensive rats. The decrease in mean arterial pressure was maximal 6 h after 10-SUYS treatment (17.9 +/- 3.2 mmHg; P < 0.05), and blood pressure returned to baseline levels within 24 h after treatment. Treatment with 10-SUYS was associated with a decrease in urinary 20-HETE formation in vivo and attenuation of the vasoconstrictor response of renal interlobar arteries to ANG II in vitro. These results provide further evidence that 20-HETE plays an important role in the regulation of blood pressure in the spontaneously hypertensive rat.     

Escherichia coli genes involved in resistance to pyrazinoic acid,the active component of the tuberculosis drug pyrazinamide

The natural resistance of Escherichia coli to pyrazinoic acid (POA), the active derivative of pyrazinamide, was investigated. The TolC mutant was found to be more susceptible to POA and other weak acids than the wild-type strain. Mutation in EmrB but not AcrB efflux protein slightly increased POA susceptibility. Two transposon mutants with increased susceptibility to POA were found to harbor mutations in acnA encoding aconitase-1 and ygiY encoding a putative two-component sensor protein. Complementation of the AcnA and YgiY mutants conferred resistance to POA, whereas the complemented TolC mutant became resistant to POA and other weak acids.