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21.
A new selective medium (APCA medium) was developed for the isolation of Burkholderia caryophylli , the causal agent of carnation bacterial wilt, from both plants and soil. The optimal concentration and combination of antibiotics was investigated to determine the most selective condition for growing B .  caryophylli . The resultant composition of the medium per litre was: 0·79 g (NH4)2SO4, 1·0 g KH2PO4, 0·5 g MgSO4 · 7H2O, 0·2 g KCl, 2·0 g D-arabinose, 5 mg crystal violet, 50 mg cycloheximide, 50 mg polymyxin B sulphate, 50 mg ampicillin sodium, 10 mg chloramphenicol, 25 mg blue tetrazolium, and 15 g agar. Plating efficiency ranged from 119 to 174% with an average of 141% compared to that of nutrient agar. The bacterium was successfully isolated from contaminated soil and plant tissues with this medium. Moreover, the medium almost completely inhibited the growth of other plant pathogenic bacteria and soil saprophytes. This selectivity was high enough to detect B . caryophylli in contaminated soil.  相似文献   
22.
To develop a high density linkage map in faba bean, a total of 1,363 FBES (Faba bean expressed sequence tag [EST]-derived simple sequence repeat [SSR]) markers were designed based on 5,090 non-redundant ESTs developed in this study. A total of 109 plants of a ‘Nubaria 2’ × ‘Misr 3’ F2 mapping population were used for map construction. Because the parents were not pure homozygous lines, the 109 F2 plants were divided into three subpopulations according to the original F1 plants. Linkage groups (LGs) generated in each subpopulation were integrated by commonly mapped markers. The integrated ‘Nubaria 2’ × ‘Misr 3’ map consisted of six LGs, representing a total length of 684.7 cM, with 552 loci. Of the mapped loci, 47% were generated from multi-loci diagnostic (MLD) markers. Alignment of homologous sequence pairs along each linkage group revealed obvious syntenic relationships between LGs in faba bean and the genomes of two model legumes, Lotus japonicus and Medicago truncatula. In a polymorphic analysis with ten Egyptian faba bean varieties, 78.9% (384/487) of the FBES markers showed polymorphisms. Along with the EST-SSR markers, the dense map developed in this study is expected to accelerate marker assisted breeding in faba bean.  相似文献   
23.
Leg weakness in pigs is a serious problem in the pig industry. We performed a whole genome quantitative trait locus (QTL) analysis to find QTLs affecting leg weakness traits in the Landrace population. Half-sib progeny ( n  = 522) with five sires were measured for leg weakness traits. Whole genome QTL mapping was performed using a half-sib regression-based method using 190 microsatellite markers. No experiment-wide significant QTLs affecting leg weakness traits were detected. However, at the 5% chromosome-wide level, QTLs affecting leg weakness traits were detected on chromosomes 1, 3, 10 and 11 with QTL effects ranging from 0.07 to 0.11 of the phenotypic variance. At the 1% chromosome-wide level, QTLs affecting rear feet score and total leg score were detected on chromosomes 2 and 3 with QTL effects of 0.11 and 0.13 of the phenotypic variance, respectively. On chromosome 3 and 10, some QTLs found in this study were located at nearby positions. The present study is one of the first reports of QTLs affecting fitness related traits such as leg weakness traits, that segregate within the Landrace population. The study also provides useful information for studying QTLs in purebred populations.  相似文献   
24.
Canine CD20 gene     
The human CD20 antigen, a 35kDa cell surface nonglycosylated hydrophobic phoshpoprotein is expressed consistently on almost all human B-cells, and its monoclonal antibody is used for the therapy on human B-cell lymphoma. In the present study, canine CD20 gene was cloned and sequenced, and the expression of CD20 mRNA was investigated in canine peripheral blood mononuclear cells (PBMCs), and lymph nodes from healthy dogs, and canine lymphoma cells. Using canine cDNA as a template, full-length of canine CD20 gene was sequenced by 5'-RACE and 3'-RACE methods. The full-length of the cDNA sequence of canine CD20 was 1239bp encoding 297 amino acids. The amino acid sequences of canine CD20 showed 73 and 68% sequence similarities with those of human and mouse, respectively. Canine CD20 was predicted to contain domains of amino acid sequences consisting of two extracellular domains (EM), four transmembrane domains (TM), and three intracellular domains (IC) as in human CD20. Canine CD20 mRNA was detected in PBMCs and lymph node from healthy dogs, and B-cells of canine lymphoma, but not in T-cell lymphoma cells and non-T and non-B-cell lymphoma cells by RT-PCR analysis. From these results, canine CD20 might be targeted for monoclonal antibody therapy against B-cell lymphoma of dogs.  相似文献   
25.
ABSTRACT Efficiency of nonpathogenic Fusarium oxysporum Fo-B2 for the biological control of Fusarium wilt of tomato, caused by F. oxysporum f. sp. lycopersici CU1, was examined in different environments: a growth chamber with sterile soil-less medium, a greenhouse with fumigated or nonfumigated soil, and nonfumigated field plots. Inoculation of Fo-B2 onto tomato roots significantly reduced the severity of disease, but the efficiency of disease suppression decreased as the experimental environment became less controlled. Relationships between the recovery of Fo-B2 from hypocotyls and the disease severity indicated that the biocontrol agent was most effective when it colonized vascular tissues intensively. Moreover, the degree of Fo-B2 colonization was greatly reduced when the seedlings were grown in nonfumigated soil. Dose-response models (negative exponential, hyperbolic saturation, and logistic) were fit to observed data collected over a range of inoculum densities of the pathogen and the antagonist; the logistic model provided the best fit in all environments. The ratios of an 50% effective dose parameter for Fo-B2 to that of CU1 increased as the environment became less controlled, suggesting that environmentally related efficiency reduction impacted the antagonist more than the pathogen. The results suggest that indigenous soil microbes were a primary factor negatively influencing the efficiency of Fo-B2. Therefore, early establishment of the antagonist in a noncompetitive environment prior to outplanting could improve the efficacy of biological control.  相似文献   
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27.
A better understanding of the relationships among different cropping systems, their effects on soil microbial ecology, and their effects on crop health and productivity is necessary for the development of more efficient, sustainable crop production systems. We used denaturing gradient gel electrophoresis (DGGE) to determine the impacts of crop rotations and crop types on bacterial and fungal communities in the soil. The communities of bacterial 16S rRNA genes and fungal 18S rRNA genes were analyzed in experimental field plots that were kept under 4 different crop rotation systems from 1999 to 2008 (continuous cabbage (Brassica oleracea var. capitata L.), cabbage–lettuce (Lactuca sativa L.) rotation, cabbage–radish (Raphanus sativus L. var. longipinnatus L.H. Bailey) rotation, and a 3-year crop rotation). A principal component analysis (PCA) and a canonical correspondence analysis (CCA) revealed that both the bacterial and fungal communities in bulk soils were influenced by the crop rotation systems. However, the primary factors influencing each community differed: bacterial communities were most affected by soil properties (especially carbon content), while fungal communities were influenced most strongly by rotation times. To elucidate factors that may cause differences in crop rhizosphere microbial communities, the microbial communities in the harvested cabbage rhizospheres were also analyzed. The results suggest that the fungal communities in bulk soil are related to the rhizosphere fungal communities. Our present study indicates that the microbial communities in bulk and rhizosphere soils could be managed by crop rotation systems.  相似文献   
28.
Paddy field is a major emission source of methane. Methane is the terminal product of anaerobic decomposition of organic matter and generated by methanogenic archaea under flooded conditions in paddy fields. This study aimed to reveal the effect of winter flooding on methanogenic archaeal community structure in paddy fields of Andosols under organic farming. Soil samples were collected from experimental paddy fields in the Field Science Center, Tohoku University, for two years. They were under flooding conditions during winter with organic farming, under non-flooding conditions during winter with organic farming and under non-flooding conditions during winter with conventional farming (non-organic farming). Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of methanogenic archaeal 16S rRNA gene revealed that the DGGE patterns were nearly the same irrespective of the treatment and sampling times. Twenty-three bands were observed from each treatment and 4, 13 and 6 sequences were closely related to Methanomicrobiales, Methanosarcinales and Methanocellales, respectively. Real-time quantitative PCR analysis indicated that the abundance of methanogenic archaeal 16S rRNA gene and mcrA gene, encoding α subunit of methyl-coenzyme M reductase, was not significantly different among the paddy fields. This study first revealed a methanogenic archaeal community in an Andosol paddy field and showed that the community was not affected by winter flooding under organic farming.  相似文献   
29.
To analyze genetic relationships among Colletotrichum gloeosporioides isolates; 34 isolates were collected from strawberries all over Japan, but primarily from Chiba Prefecture, and 20 were isolated from hosts other than strawberry. These isolates were assayed for virulence on strawberries and subjected to a fingerprint (FP) analysis by repetitive extragenic palindromic-PCR. Most of the isolates that were highly virulent to strawberries had relatively similar FPs even though they were isolated from various host plants (strawberry, cyclamen, nipplefruit and Japanese pear) in different regions. A cluster analysis revealed that the highly virulent and the weakly virulent isolates tended to form individual clusters, indicating that the highly virulent strains of C. gloeosporioides, which were genetically close to isolates with similar FPs and distinguishable from the weakly virulent strains, were responsible for strawberry anthracnose in Japan.  相似文献   
30.
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