Listeria monocytogenes in spontaneous abortions in humans and its detection by multiplex PCR

AIM: To assess the extent of Listeria monocytogenes in causation of human spontaneous abortions by isolation methods and PCR analysis for the presence of virulence-associated genes. METHODS AND RESULTS: A total of 305 samples comprising blood, urine, placental bits, faecal and vaginal swabs were collected from 61 patients with spontaneous abortions. Listeria spp. were isolated from 10 samples collected from nine (14.8%) patients. Confirmation of these isolates was based on biochemical tests, haemolysis on blood agar, CAMP test, phosphatidylinositol-specific phospholipase C (PI-PLC) assay followed by in vivo pathogenicity tests and multiplex PCR to detect virulence-associated genes (prfA, plcA, hlyA, actA and iap). Three isolates were confirmed as L. monocytogenes. Of these, two isolates turned out to be pathogenic and found to posses all five genes. However, the remaining two haemolytic L. monocytogenes isolates lacking the plcA gene and activity in the PI-PLC assay were found to be nonpathogenic by in vivo tests. CONCLUSIONS: The occurrence of pathogenic L. monocytogenes in cases of spontaneous abortions was 3.3%. It seems that the plcA gene and its expression have an important role as essential virulence determinants in pathogenic Listeria spp. SIGNIFICANCE AND IMPACT OF THE STUDY: The recovery of pathogenic L. monocytogenes isolates from cases of spontaneous abortion indicates the significance of listeric infection in pregnant women.     

转双价抗虫基因毛白杨无性系85号抗虫性研究

以优化的毛白杨无性系85号最适遗传转化体系为基础,通过农杆菌介导法将Bt(CryⅠAc)和API双价抗虫基因导入毛白杨无性系85号基因组.在高浓度卡那霉素的培养基上诱导不定芽和根,初步选择到200株转化植株,PCR检测显示,66株呈阳性反应.Southern杂交和ELISA检测进一步证明,Bt(CryⅠAc)和API双价抗虫基因已整合到毛白杨无性系85号基因组中,并得到了表达.对转化植株用舞毒蛾幼虫进行饲虫试验,结果显示昆虫幼虫的死亡率高达60.0%~77.8%,且存活幼虫的生长发育也受到了明显抑制.研究结果为杨树抗虫育种提供了新的种质资源.     

海洋单胞菌的研究进展

简要综述了近年国、内外对海洋单胞菌的一些研究进展,包括分类地位、生态分布、功能基因和活性分子等,并对其未来发展趋势进行了展望.     

The genetic basis of graves' disease

The presented comprehensive review of current knowledge about genetic factors predisposing to Graves' disease (GD) put emphasis on functional significance of observed associations. In particular, we discuss recent efforts aimed at refining diseases associations found within the HLA complex and implicating HLA class I as well as HLA-DPB1 loci. We summarize data regarding non-HLA genes such as PTPN22, CTLA4, CD40, TSHR and TG which have been extensively studied in respect to their role in GD. We review recent findings implicating variants of FCRL3 (gene for FC receptor-like-3 protein), SCGB3A2 (gene for secretory uteroglobin-related protein 1- UGRP1) as well as other unverified possible candidate genes for GD selected through their documented association with type 1 diabetes mellitus: Tenr-IL2-IL21, CAPSL (encoding calcyphosine-like protein), IFIH1(gene for interferon-induced helicase C domain 1), AFF3, CD226 and PTPN2. We also review reports on association of skewed X chromosome inactivation and fetal microchimerism with GD. Finally we discuss issues of genotype-phenotype correlations in GD.     

Molecular analysis of methane monooxygenase from Methylococcus capsulatus (Bath)

Methane monooxygenase (MMO) is the enzyme responsible for the conversion of methane to methanol in methanotrophic bacteria. In addition, this enzyme complex oxidizes a wide range of aliphatic and aromatic compounds in a number of potentially useful biotransformations. In this study, we have used biochemical data obtained from purification and characterization of the soluble MMO from Methylococcus capsulatus (Bath), to identify structural genes encoding this enzyme by oligonucleotide probing. The genes encoding the and subunits of MMO were found to be chromosomally located and were linked in this organism. We report here on the analysis of a recombinant plasmid containing 12 kilobases of Methylococcus DNA and provide the first evidence for the localization and linkage of genes encoding the methane monooxygenase enzyme complex. DNA sequence analysis suggests that the primary structures of the and subunit of MMO are completely novel and the complete sequence of these genes is presented.     

小麦Kr基因在小麦与玉米或鸭茅状摩擦禾杂交中的失活

用３７个小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ）品种（系）为母本,分别与黑麦（Ｓｅｃａｌｅｃｅｒｅａｌｅ）、球茎大麦（Ｈｏｒｄｅｕｍｂｕｌｂｏｓｕｍ）、玉米（Ｚｅａｍａｙｓ）和鸭茅状摩擦禾（Ｔｒｉｐｓａｃｕｍｄａｃｔｙｌｏｉｄｅｓ）杂交,比较其亲和性,小麦和玉米或鸭茅状摩擦禾杂交比小麦与黑麦或球茎大麦杂交的亲和性显著提高。携带着显性Ｋｒ１和Ｋｒ２基因的小麦品种Ｈｏｐｅ与黑麦杂交,不能形成胚,而与玉米及鸭茅状摩擦禾杂交时,成胚率分别达１６．００％和３２．５０％。表明控制小麦与黑麦及球茎大麦杂交亲和性的Ｋｒ基因系统在小麦与玉米及小麦与鸭茅状摩擦禾属间杂交中失活。讨论了还存在有其它控制小麦属间杂交亲和性的遗传调控系统的可能性。     

Sequence-tagged-site (STS) markers of arbitrary genes: the utility of black spruce-derived STS primers in other conifers

 Sequence-tagged-site primers, previously developed based upon black spruce (Picea mariana) cDNA sequences, were tested for their ability to direct specific amplification in two individuals of each of 12 additional conifer species. Nearly all (95–97%) of the primers functioned well in congeneric trials, while a lower proportion (21–33%) scored positively in other Pinaceae genera. Outside of the Pinaceae, amplification of homologous products was not achieved. Products from the various species often differed in size from their homologs in black spruce. In one case a large difference in size was due to the lack of an intron in a jack pine product while in several other cases the differences were due to the presence or absence of large direct repeats in the DNA sequences. Length polymorphism was occasionally evident between the two individuals examined of a given species. We investigated marker polymorphism in detail in a panel of 15 white spruce (Picea glauca) trees. Allelic segregation among haploid megagametophytes was revealed directly at 16 loci by standard agarose-gel electrophoresis without any additional manipulation of amplification products. Polymorphisms observed at 12 of these loci were exclusively co-dominant. For this subset of 12 loci, the average number of alleles was 3.2 and the average observed heterozygosity was 0.37. Received: 10 April 1998 / Accepted: 22 April 1998     

Association between dwarfing genes ‘Rht1’ and ‘Rht2’ and resistance toSeptoria tritici Blotch in winter wheat (Triticum aestivum L. em Thell)

Summary Differences in levels of resistance toSeptoria tritici blotch were observed in plants with a specific height-reducing gene. When the gene Rht ₂ was present either as an isoline or in the progeny, a higher degree of resistance was found. The most susceptible plants were observed in populations carrying the Rht ₁ gene. Associations, as determined by phenotypic correlations, were detected betweenSeptoria tritici blotch and tall stature, late heading, and maturity. Plants having short stature, early heading, early maturity, and acceptable levels of resistance were identified in the F₂ population whenRht ₂ was present. Results of this study indicated that wheat breeders must select the appropriate dwarfing source that may confer resistance and grow large F₂ populations, in order to increase the probability of obtaining desired genotypes.     

玉米细胞质雄性不育及其育性恢复基因的研究进展

玉米是杂种优势利用最成功的作物之一,采用细胞质雄性不育(CMS)进行玉米杂交种生产已成为杂种优势利用的有力工具。CMS是由于细胞质和细胞核的基因表达产物的不协调而产生的不育性,可被核基因组中的恢复基因恢复。根据育性恢复专效性,玉米CMS材料主要分为T、C和S三种类型。综述了这三种类型不育及其恢复基因的研究进展,分析了在不育化制种中的应用情况。