Morphological, Host Range, and Genetic Characterization of Two Coliphages

Two coliphages, AR1 and LG1, were characterized based on their morphological, host range, and genetic properties. Transmission electron microscopy showed that both phages belonged to the Myoviridae; phage particles of LG1 were smaller than those of AR1 and had an isometric head 68 nm in diameter and a complex contractile tail 111 nm in length. Transmission electron micrographs of AR1 showed phage particles consisting of an elongated isometric head of 103 by 74 nm and a complex contractile tail 116 nm in length. Both phages were extensively tested on many strains of Escherichia coli and other enterobacteria. The results showed that both phages could infect many serotypes of E. coli. Among the enterobacteria, Proteus mirabilis, Shigella dysenteriae, and two Salmonella strains were lysed by the phages. The genetic material of AR1 and LG1 was characterized. Phage LG1 had a genome size of 49.5 kb compared to 150 kb for AR1. Restriction endonuclease analysis showed that several restriction enzymes could degrade DNA from both phages. The morphological, genome size, and restriction endonuclease similarities between AR1 and phage T4 were striking. Southern hybridizations showed that AR1 and T4 are genetically related. The wide host ranges of phages AR1 and LG1 suggest that they may be useful as biocontrol, therapeutic, or diagnostic agents to control and detect the prevalence of E. coli in animals and food.     

Genetic and Pathobiologic Characterization of Pandemic H1N1 2009 Influenza Viruses from a Naturally Infected Swine Herd

Since its initial identification in Mexico and the United States, concerns have been raised that the novel H1N1 influenza virus might cause a pandemic of severity comparable to that of the 1918 pandemic. In late April 2009, viruses phylogenetically related to pandemic H1N1 influenza virus were isolated from an outbreak on a Canadian pig farm. This outbreak also had epidemiological links to a suspected human case. Experimental infections carried out in pigs using one of the swine isolates from this outbreak and the human isolate A/Mexico/InDRE4487/2009 showed differences in virus recovery from the lower respiratory tract. Virus was consistently isolated from the lungs of pigs infected with A/Mexico/InDRE4487/2009, while only one pig infected with A/swine/Alberta/OTH-33-8/2008 yielded live virus from the lung, despite comparable amounts of viral RNA and antigen in both groups of pigs. Clinical disease resembled other influenza virus infections in swine, albeit with somewhat prolonged virus antigen detection and delayed viral-RNA clearance from the lungs. There was also a noteworthy amount of genotypic variability among the viruses isolated from the pigs on the farm. This, along with the somewhat irregular pathobiological characteristics observed in experimentally infected animals, suggests that although the virus may be of swine origin, significant viral evolution may still be ongoing.The zoonotic potential of swine influenza viruses is well recognized (18), and pigs have been considered a leading candidate for the role of intermediate host in the generation of reassortant influenza A viruses with pandemic potential. This has been largely based on genomic analysis of influenza A viruses isolated from swine and the fact that α2,3-linked sialic acid (avian-like) and α2,6-linked sialic acid (human-like) receptors are both abundant in the swine respiratory tract (12). Despite this, there is no direct evidence that the reassortment of the 1957 and the 1968 human pandemic viruses occurred in pigs (28). Furthermore, it is very likely that the 1918 pandemic virus was introduced to pigs from humans (8, 31). The origins of influenza A viruses that have been isolated from pigs include those that are wholly human or avian, as well as reassortants containing swine, human, and avian genes (2, 20, 29). Although there have been several instances of swine-to-human transmission, for example, that of triple-reassortant swine influenza (H1) viruses (rH1N1), which appeared after 1998, they did not lead to establishment of sustained transmission in the human population (23).In the early spring of 2009, Mexico and the United States reported clusters of human pneumonia cases caused by a novel H1N1 influenza A virus. This virus subsequently spread across the globe at an unprecedented rate, prompting the WHO to declare a pandemic in June 2009. Phylogenetic analysis has inferred that the virus is likely a reassortant between a North American triple-reassortant swine H1N1 or H1N2 virus and a Eurasian lineage H1N1 swine influenza virus (7, 19). Bayesian molecular-clock analysis of each gene of this novel H1N1 virus (24) concluded that the mean evolutionary rate is typical of that of swine influenza viruses but that the duration of unsampled diversity for each gene segment had means that ranged from 9.24 to 17.15 years, suggesting that the proposed ancestors of this virus may have been circulating undetected for nearly a decade. Inadequate surveillance and characterization of influenza A viruses that circulate in swine have been blamed for this evolutionary gap.On 28 April 2009 the Canadian Food Inspection Agency (CFIA) became involved in a suspected outbreak of swine influenza on a pig farm in Leslieville, Alberta, Canada. The farm was a 220-sow farrow-to-finish operation consisting of approximately 2,200 animals that ranged from newborn piglets to market weight pigs. The animals were not vaccinated against swine influenza, and although there had been prior problems with porcine reproductive and respiratory syndrome virus and Mycoplasma hypopneumoniae, two etiologic agents of the swine respiratory disease complex, the herd had been stable with respect to respiratory disease. Beginning 20 April, approximately 25% of the pregrower and grower pigs in two of the barns exhibited respiratory problems with clinical signs that included an acute onset of coughing, lethargy, and loss of appetite. These clinical signs were preceded by the hiring of a carpenter on 14 April to work on the ventilation system in the same two barns. This individual had been ill for 2 days after his return from Mexico on 12 April (10). Given the evolving situation in Mexico and the United States, the CFIA and Alberta Agriculture and Rural Development decided to place the herd under quarantine and to carry out a full epidemiological and laboratory investigation.Here, we report on the characterization of the first pandemic H1N1 2009 viruses to be isolated from a naturally infected pig herd. Genetic sequence data from several viruses isolated from this outbreak have provided a glimpse into the mutation frequencies associated with replication of the virus in the swine host. Experimental infections of pigs comparing one of these swine isolates with the human isolate A/Mexico/InDRE4487/2009(H1N1) were also carried out and have provided insights into the pathobiological behavior of these viruses in pigs.     

Characterization of PUD-1 and PUD-2, Two Proteins Up-Regulated in a Long-Lived daf-2 Mutant

C. elegans PUD-1 and PUD-2, two proteins up-regulated in daf-2(loss-of-function) (PUD), are homologous 17-kD proteins with a large abundance increase in long-lived daf-2 mutant animals of reduced insulin signaling. In this study, we show that both PUD-1 and PUD-2 are abundantly expressed in the intestine and hypodermis, and form a heterodimer. We have solved their crystal structure to 1.9-Å resolution and found that both proteins adopt similar β-sandwich folds in the V-shaped dimer. In contrast, their homologs PUD-3, PUD-4, PUDL-1 and PUDL-2 are all monomeric proteins with distinct expression patterns in C. elegans. Thus, the PUD-1/PUD-2 heterodimer probably has a function distinct from their family members. Neither overexpression nor deletion of pud-1 and pud-2 affected the lifespan of WT or daf-2 mutant animals, suggesting that their induction in daf-2 worms does not contribute to longevity. Curiously, deletion of pud-1 and pud-2 was associated with a protective effect against paralysis induced by the amyloid β-peptide (1-42), which further enhanced the protection conferred by daf-2(RNAi) against Aβ.     

山羊乳中上皮粘蛋白MUC1的遗传多态性

采用SDS PAGE方法研究了波尔山羊、成都麻羊、安哥拉山羊×藏山羊F1、建昌黑山羊、安哥拉山羊×建昌黑山羊F1乳MUC1的生化遗传特性。结果表明 :山羊乳MUC1呈现出多态性 ,表现为 1条或 2条迁移率不同的区带。SDS PAGE分析发现 4种分子量的MUC1区带 ,即A、B、C和D ,分子量分别为 2 6 4、 2 41、 2 31和 2 2 0kDa ,大于牦牛和荷斯坦牛乳中的MUC1。基因型与山羊品种有关 ,在波尔山羊中最丰富 ,有 10种基因型 ,基因杂合度为 0 72 72 ;建昌黑山羊有 3种基因型 ,基因杂合度为 0 495 0 ;而在成都麻羊中仅发现CC基因型。经适合性检验 ,波尔山羊、成都麻羊、建昌黑山羊乳MUC1基因座基因型分布符合哈代 -温伯格定律     

Immunological Characterization of cdc2 and wee1 Proteins during the Growth and Differentiation of Dictyostelium discoideum

Two different antibody preparations, raised independently against the conserved EGVPSTAIREISLLKE sequence of the protein kinases encoded by the Schizosaccharomyces pombe cdc2 gene and its species homologs, immunoblotted a Dictyostelium protein of 32 kDa (p32). This polypeptide bound to p13^suc1-agarose beads, suggesting that it represents the Dictyostelium cdc2 and / or cdk2 products. The amounts of p32 detectable in cell free extracts and bound to p13^suc1-agarose were unaltered during the growth of cells synchronized for division. Although there was also essentially no change in the level of p32 during differentiation, the protein from the pseudoplasmodial stage of development did not bind to p13^suc1-agarose, implicating a developmentally regulated modification of the kinase. One of the EGVPSTAIREISLLKE antibodies also recognized a protein of 49 kDa (p49) that increased in amount dramatically during aggregation and then remained at elevated levels throughout the remainder of the differentiation process. This protein was present in low amounts throughout the growth of cells synchronized for division and was not absorbed by p13^suc1-agarose.
A 103 kDa protein (p103) was detected by Western blot analysis using antibodies raised against two different peptides corresponding to sequences in the S. pombe protein kinase p105^wee1, which is a putative upstream negative regulator of p34^cdc2 in fission yeast. The levels of p103 were constant during differentiation and during the growth of cells synchronized for division.     

猪MyoG基因内含子1的一个遗传多态性及其遗传效应分析

以长白猪(73),大白猪(68),沂蒙黑猪(57)和莱芜猪(83)为研究对象,采用PCR-SSCP方法 对猪MyoG基因遗传多态性进行分析,并研究基因型与初生重、日增重、肌肉嫩度和背膘厚的相关性.根据猪MyoG 基因的DNA序列（M14331）设计引物,结果在内含子1扩增的片段上发现了一个多态性,检测到2个等位基因(A、B),3种基因型（AA、AB、BB）,并对纯合子进行测序,发现2　943位G→C突变.基因型在不同猪种分布的多重比较,结果表明,大白猪与长白猪、沂蒙黑猪和莱芜猪比较差异显著（P<0.05）,莱芜猪与长白猪和沂蒙黑猪比较差异显著（P<0.05）,长白猪与沂蒙黑猪比较差异不显著（P>0.05）.固定效应模型分析结果表明,初生重及嫩度基因型间差异显著（P<0.01）,而日增重及背膘厚基因型间差异不显著（P>0.05）.最小二乘分析结果表明,BB基因型个体与AA基因型个体比较肌肉嫩度的差异显著（P<0.05）,AA基因型个体与AB和BB基因型个体比较背膘厚的差异显著（P<0.05）.因此,推测MyoG基因对猪肉品质、生长速度及背膘厚存在一定的影响,将 MyoG基因应用于猪育种过程中的标记辅助选择将可以改善猪肉品质,提高生长速度,加快猪的育种进程.     

云南汉族群体FIBRA、DHFRP2、ACTBP2基因座多态性及其法医学应用

采用Amp-FLP分型方法,调查云南汉族群体FIBRA、DHFRP2、ACTBP2基因座的遗传多态性,并将其应用于法医学实践。200份EDTA抗凝血采自昆明地区无血缘关系汉族个体,采用酚—氯仿法提取DNA;法医物证实际检案及亲子鉴定检材取自昆明医学院法医系物证教研室检案,各种动物血痕取自动物中心,采用酚—氯仿法或Chelex法提取DNA,PCR扩增,非变 性聚丙烯酰胺凝胶垂直板电泳,硝酸银染色分型。结果表明,FIBRA、DHFRP2、ACTBP2基因座分别观察到15、7、13个等位基因,基因型数分别是57、25、61。3个STR基因座的杂合度（H）分别为：0.8940、0.8174、0.9130;多态信息容量（PIC）分别是:0.8908、0.8045、0.9117;个人识别力（Dp）分别是：0.9733、0.9416、0.9772;非父排除率（Epp）分别是：0.7994、0.6542、0.8348,基因型频率分布均符合Hardy-Weinberg平衡。20个家系调查结果表明,3个基因组均符合孟德尔遗传规律。 Genetic Polymorphism of FIBRA,DHFRP2 and ACTBP2 and Their Forensic Application in Yunnan Han Population JING Qiang,NIE Sheng-jie Department of Forensic Medicine,Kunming Medical College,Yunnan Province 650031,China Abstract:To investigate the genetic polymorphism of FIBRA,DHFRP2 and ACTBP2 in Yunnan Han population as well as their application in forensic science,EDTA-blood specimens were collected from 200 healthy individuals.The DNA were extracted either by the Chloro form,phenol method or by the Chelex-100 method.The PCR products were analyzed by PAG vertical electrophoresis,following by silver staining.All gene frequencies,discrimination power (DP),exclusion of paternity probability (EPP),heterozygosity (H),polymorphisms information content (PIC),matching probability (PM) as well as the Hardy-Weinberg test were calculated.The obtained data are beneficial in the understanding of population genetics of the three STR loci in Yunnan Han population and the results suggest that these loci are valuable genetic markers for paternity testing and personal identification in forensic science practice. Key words：short tandem repeat; Amp-FLP; genetic polymorphism     

猪2号染色体遗传连锁图谱的构建与QTL定位分析

构建了猪2号染色体的遗传连锁图谱,并进一步进行了重要生产性状数量性状位点的定位,结果表明,7个微卫星位点均为中高度多态性位点,多态信息含量为0．40182－0．58477,可以满足遗传连锁图谱构建的要求,构建的资源家系遗传连锁图谱总长152．9cM,位点的排列顺序与USDA结果一致,但除了Sw2516与Sw1201标记区间外,所有标记区间距离均大于USDA图谱,将连锁图谱与性状记忆结合起来,进一步进行了猪数量性状位点定位的研究,在2号染色体发现了显著影响活体估测瘦肉率等活体估测性状的QTLs,此外还发现眼肌高度和背最长肌大理石纹的QTLs,其中影响活体估测瘦肉率的QTL达到了染色体显著的水平（P＜0．01）,且解释性状的表型变异达21．55％,影响眼肌高度和背最长肌大理石纹的QTLs分别可以解释10．12％和10．97％的表型变异,影响活体估测性状的QTLs加性效应与显性效应作用方向相反,影响眼肌高度的QTL加性效应与显性效应相同,在大白猪中具有增效等位基因,定位的QTLs效应较大,为在群体中开展分子标记辅助育种奠定了理论基础。     

细胞色素P450 1A1基因多态性与我国某些肿瘤遗传易感性

近年来有关细胞色素P450基因多态性与肿瘤遗传易感性的研究正日益吸引越来越多的关注,本文对我国近年来有关细胞色素P450 1A1(CYP1Al)基因多态性与几种肿瘤遗传易感性的研究进行探讨,推测我国几种高发病率肿瘤的发生与我国CYP1A1基因多态分布状况有关,以此为进一步研究CYP1A1与肿瘤的关系作参考。     

中国广东人红细胞PGM_1亚型遗传性多态现象

采用薄层聚丙烯酰胺凝胶等电聚焦技术,调查了中国(广东)406名无亲缘关系的正常人红细胞磷酸葡萄糖变位酶-1(PGM_1)亚型的遗传多态性。除了常见的10种亚型外,还发现了由一个新的变异型等位基因和常见的4个等位基因杂合产生的9例变异型。PGM_1位点的等位基因频率PGM_1~(1+)、PGM_1~(1-)、PGM_1~(2+)、PGM-1~(2-)和PGM_1~(V丰)(变异型等位基因)分别为0.5973、0.1256、0.1724、0.0936和0.0111;群体处于Hardy-Weinberg式平衡状态。变异型等位基因以多态频率出现,可能成为该群体的一个重要的遗传性特征。     

Immunological Characterization of Iron-Regulated Membrane Proteins in the Cyanobacterium Anacystis nidulans R2

Antibodies cross-reactive with specific membrane proteins were used to investigate membrane development in Anacystis nidulans R2 during recovery from iron stress. Polyclonal antibodies prepared using the iron-regulated chlorophyll (Chl)-protein CPVI-4 (HB Pakrasi, HC Riethman, LA Sherman 1985 Proc Natl Acad Sci USA 82: 6903-6907) as antigen were characterized and used to identify three iron stress-induced polypeptides of 36, 35, and 34 kilodaltons on immunoblots of polyacrylamide gels. The 34 kilodalton protein was shown to be a component of the Chlbinding CPVI-4 complex. The 36 kilodalton protein is an unrelated, intrinsic membrane protein tightly regulated by iron (designated IrpA), whereas the 35 kilodalton immunoreactive component is an extremely abundant glycoprotein (GP35). An analysis of photosystem II (PSII)-associated Chl-proteins during recovery from iron stress demonstrates that CPVI-4 is associated with most of the Chl present in iron-starved cells, whereas the PSII core polypeptides are present in very low levels; upon recovery, CPVI-4 diminishes in abundance as the relative levels of the other PSII proteins increase. The abundance of CPVI-4 in iron-stressed cells and the distribution of Chl among individual Chl-proteins during recovery suggest a possible role for CPVI-4 in the direction of membrane assembly during recovery from iron stress.     

Immunogenetic analysis of H-2 mutations. III. Genetic mapping and involvement in immune reactions of the H-2ka mutation.

Mutation M523 (H-2ka) occurred spontaneously in strain CBA/CaLacSto and was discovered during routine skin graft testing for genetic homogeneity. By linkage and complementation tests, the mutation was previously mapped in the K end of the H-2 complex. We demonstrate that the mutation occurred in the K region, without affecting the I region in the K end of the complex. The mutant antigens cause rejection of skin grafts, stimulate cells in mixed lymphocyte culture, and function as stimulators as well as targets in cell-mediated lymphocytotoxicity. Yet, they are serologically indistinguishable from the antigens of the original strain and do not induce formation of humoral antibodies upon immunization of the CBA strain. Together with the results obtained on testing of other H-2 mutants, the data strongly support the notion that classical H-2 antigens (i.e., products of the H-2K and H-2D loci) can function as lymphocyte-stimulating determinants, and that I-region differences are not required for the induction of strong cell-mediated lymphocytotoxicity.