Mutants in the lipopolysaccharide of Brucella ovis are attenuated and protect against B. ovis infection in mice     

Pedro Soler-Lloréns  Yolanda Gil-Ramírez  Ana Zabalza-Baranguá  Maite Iriarte  Raquel Conde-álvarez  Amaia Zú?iga-Ripa  Beatriz San Román  Michel S Zygmunt  Nieves Vizcaíno  Axel Cloeckaert  María-Jesús Grilló  Ignacio Moriyón  Ignacio López-Go?i 《Veterinary research》2014,45(1):72

Brucella spp. are Gram-negative bacteria that behave as facultative intracellular parasites of a variety of mammals. This genus includes smooth (S) and rough (R) species that carry S and R lipopolysaccharides (LPS), respectively. S-LPS is a virulence factor, and mutants affected in the S-LPS O-polysaccharide (R mutants), core oligosaccharide or both show attenuation. However, B. ovis is naturally R and is virulent in sheep. We studied the role of B. ovis LPS in virulence by mutating the orthologues of wadA, wadB and wadC, three genes known to encode LPS core glycosyltransferases in S brucellae. When mapped with antibodies to outer membrane proteins (Omps) and R-LPS, wadB and wadC mutants displayed defects in LPS structure and outer membrane topology but inactivation of wadA had little or no effect. Consistent with these observations, the wadB and wadC but not the wadA mutants were attenuated in mice. When tested as vaccines, the wadB and wadC mutants protected mice against B. ovis challenge. The results demonstrate that the LPS core is a structure essential for survival in vivo not only of S brucellae but also of a naturally R Brucella pathogenic species, and they confirm our previous hypothesis that the Brucella LPS core is a target for vaccine development. Since vaccine B. melitensis Rev 1 is S and thus interferes in serological testing for S brucellae, wadB mutant represents a candidate vaccine to be evaluated against B. ovis infection of sheep suitable for areas free of B. melitensis.  相似文献   

Purification of chinook salmon (Oncorhynchus tshawytscha) GH for receptor study     

Pierre-Yves Le Bail  Geneviève Boulard  Bruno Barenton  Michel Zygmunt 《Fish physiology and biochemistry》1989,7(1-6):243-251

A method for the purification of chinook Salmon (Oncorhynchus tshawytscha) GH, which retains its biological activity, is described. The biological activity was investigated with an established radioreceptor assay using liver membranes from pregnant rabbits and bovine GH as standard and labelled hormone. The enrichment of the preparation was checked with electrophoresis (SDS-PAGE). Extraction and further steps were carried out using low molarity alkaline buffer (pH 8–10, M = 100 mM). Three chromatography steps were performed (Concanavalin-A sepharose, Bio-gel P60, DEAE). Ion exchange chromatography was performed under isocratic conditions (using a 50 cm column). Two isoforms (sGH1 and sGH2) were isolated. The purification yield is 0.7% compared to lyophilized pituitaries. The molecule is homogeneous in SDS-PAGE. Contamination by prolactin, gonadotrophin and corticotrophin is negligible (< 0.5%). It could be demonstrated that the biological activity of the preparation is maintained since this preparation stimulates the growth of juvenile trout (Salmo gairdneri) and binds specifically (35%) to trout liver membranes.  相似文献   

The biodiversity of dictyostelids in mountain forests: A case study in the French Alps     

Yoan Paillet  Michel Satre 《Pedobiologia》2010,53(5):337-341

Forest management can seriously modify the biodiversity of forest dwelling species, but the consequences are poorly known for certain taxa, particularly soil fauna, for which few studies have been published. We compared the biodiversity of dictyostelids cellular slime moulds in a managed and an unmanaged forest in the French Alps and analysed the influence of environmental factors on species richness and abundance of dictyostelids. To our knowledge, this study is the first one undertaken in the European Alps. We must better understand the influence of various environmental factors on the biodiversity of these organisms if we want to accurately define their functional role in the soil. In our study, dictyostelids showed lower levels of diversity compared to previously published results. The mean species richness of dictyostelids was marginally higher in unmanaged than in managed forests and biodiversity indices were significantly correlated with elevation and pH. This suggests that environmental factors have a predominant effect on the biodiversity of dictyostelids and that the effect of forest management is secondary.  相似文献   

Development of Plant Roots Network in Polluted Soils: An X-ray Computed Microtomography Investigation     

Nicolas Seignez  Arnaud Gauthier  Florias Mess  Celia Brunel  Michel Dubois  Jean Luc Potdevin 《Water, air, and soil pollution》2010,209(1-4):199-207

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甜瓜(Cucumis melo)基因目录   总被引：2，自引：0，他引：2  

Michel Pitrat  刘文革 《中国瓜菜》2000,(2):37-40

１９９８年在国际葫芦科遗传协会年报（ＣＧＣ Ｒｅｐｏｒｔ）第 ２１期发表了最新的一份甜瓜基因目录，它包括１２０个基因，特全文翻译出来，供读者参考。  相似文献   

Experimental udder infection with Escherichia coli. 2. Morphological changes of the epithelium in the area of the glands of the milk cistern and the large milk ducts     

P Sterba  G Michel  J Schulz 《Archiv fuer experimentelle veterinaermedizin》1990,44(5):740-756

Optical light, transmission, and scanning electron microscopy were used in investigations of epithelia in the glandular region of the milk cistern and greater lactiferous ducts and yielded the following findings, four and six hours from infection: degeneration and necrosis of epithelial cells, intraepithelial foreign cell infiltration (neutrophilic granulocytes, lymphocytes, macrophages), intra-epithelial oedema and locally delimited epithelial loss. The lesions differed by intensity in various regions, so that a distinction could be made among five froms of epithelial alterations. The epithelial cells revealed their capability of absorbing pathogenic material and storing it in cytoplasmic vacuoles. This was considered to reflect active involvement of epithelium in antibacterial defence, and consequently, to reflect the role played by epithelium as a defence barrier in the milk cistern and greater lactiferous ducts.  相似文献   

Hemagglutinating activity associated with bovine herpesvirus type 1   总被引：1，自引：0，他引：1  

Pierre Trpanier  Cecile Sguin  Yolande Bastien  Gaston Boulay  Gilles Lussier  Michel Trudel 《Veterinary microbiology》1985,10(6):517-523

Using C57BL/HPB mouse erythrocytes, hemagglutination has been observed with the Los Angeles and Colorado-1 strains of bovine herpesvirus type 1 and with 12 other Canadian field isolates as well. The specificity of the hemagglutination observed with the viral strains has been confirmed by a hemagglutination-inhibition assay.  相似文献   

Type IV secretion and Brucella virulence     

Maria Laura Boschiroli  Safia Ouahrani-Bettache  Vincent Foulongne  Sylvie Michaux-Charachon  Gisele Bourg  Annick Allardet-Servent  Chantal Cazevieille  Jean-Phillipe Lavigne  Jean Pierre Liautard  Michel Ramuz  David O&#x;Callaghan 《Veterinary microbiology》2002,90(1-4)

The type IV secretion system, encoded by the virB region, is a key virulence factor for Brucella. The 12 genes of the region form an operon that is specifically induced by phagosome acidification in cells after phagocytosis. We speculate that the system serves to secrete unknown effector molecules, which allow Brucella to pervert the host cell endosomal pathways and to create a novel intracellular compartment in which it can replicate.  相似文献   

Plant transposable elements,with an emphasis on grass species     

Fran?ois?Sabot  Delphine?Simon  Michel?BernardEmail author 《Euphytica》2004,139(3):227-247

Transposable elements are presents in all known genomes so far, and have the faculty of changing their genomic location and/or number of copies within the genome. They are mobile endogenous genetic elements, with a large variety of structure and transposition mechanism. In crops, they compose the major part of the nucleic DNA, up to 80% in some cereals like maize and wheat. Despite their omnipresence, they are largely unknown and uncharacterized within the Poaceae family. In this review, we describe a possible classification of the elements present in this family, some of their known transposition mechanism, their known activity and possible action in crops, and their possible origin.  相似文献   

Metaphase-I analysis of a Triticum aestivum x T. monococcum hybrid by the C-banding technique     

Juan M. González  Sylvie Bernard  Michel Bernard 《Euphytica》1993,68(3):187-192

Summary The meiotic pairing behaviour at metaphase I of a Triticum aestivum×Triticum monococcum hybrid has been studied by means of the C-banding technique to ascertain the homology between the chromosomes in the A genome of the two species. The technique allowed the A and B genome chromosomes and the 2D, 3D and 5D chromosomes to be identified. Differences in the level of chromosome pairing in the A genome were noted. The T. monococcum 4A chromosome did not pair with any of the T. aestivum chromosomes in any of the metaphase I cells analysed. Two reciprocal translocations between the 2B and 2D chromosomes on one side and the 2A and 3D on the other side have been identified. The usefulness of the C-banding technique in the study of chromosome homology among species related to wheat is discussed.  相似文献