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131.
Malone FE Wilson EC Pollock JM Skuce RA 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2003,50(10):500-504
Tuberculosis, associated with Mycobacterium bovis infection, occurs infrequently in sheep. A sheep flock, which was potentially exposed to a high level of infection from in-contact tuberculous cattle, was examined for evidence of infection. Six sheep that had given a positive reaction to the comparative intradermal tuberculin test were examined post mortem. Tuberculous lesions were present in four of these sheep. Lesion morphology and distribution in the sheep was similar to that in cattle. M. bovis was cultured from the lesions and the isolates were strain typed by spoligotyping and variable number of tandem repeats (VNTR) typing. Tuberculin-reacting sheep also reacted positively to an assay for in vitro release of interferon-gamma. This paper describes the first report of an outbreak of tuberculosis in sheep in either Britain or Ireland. The report describes immunology and pathology findings and, using molecular typing techniques, suggests that the sheep had been infected from in-contact cattle. 相似文献
132.
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134.
Delahay RJ Wilson GJ Smith GC Cheeseman CL 《Veterinary journal (London, England : 1997)》2003,166(1):43-51
Bovine tuberculosis (TB) is a serious zoonotic disease, which despite a largely successful test and slaughter programme has persisted in cattle herds in parts of the UK. The badger (Meles meles) is widely considered to represent a significant wildlife reservoir for the transmission of Mycobacterium bovis to cattle, and has been the subject of a variety of culling strategies since the mid 1970s. Nevertheless, the incidence of herd breakdowns has continued to rise, and the efficacy of culling is currently the subject of a large-scale field trial. One potential alternative tool for the management of disease in wildlife populations is vaccination. However, the successful development of an effective vaccine and a strategy for its delivery will require careful consideration of the practical constraints imposed by ecological factors. In the current paper, we discuss relevant ecological and epidemiological characteristics of badger populations and practical aspects of vaccine delivery in the field. 相似文献
135.
Wilson Pinto Cláudia Aragão Florbela Soares Maria Teresa Dinis & Luís E C Conceição 《Aquaculture Research》2007,38(11):1198-1204
Stressful husbandry conditions are likely to affect growth and amino acid metabolism in fish. In this study, chronic ammonia exposure was used to test the effects of a stressor on growth and amino acid metabolism of Senegalese sole juveniles. The fish were exposed for 52 days to 11.6 mg L−1 [low‐TAN (L‐TAN)] or 23.2 mg L−1 [high‐TAN (H‐TAN)] of total ammonia nitrogen (TAN), or to 0 mg L−1 (Control). Growth in L‐TAN groups was slightly but significantly different from the Control groups [relative growth rate (RGR=0.35±0.13 and 0.52±0.23% day−1 respectively)]. In H‐TAN groups, growth was severely affected (RGR=0.01±0.13% day−1). Stress parameters (plasma cortisol and glucose) showed slight or no significant differences between treatments. Plasma free amino acid (FAA) concentrations were affected after H‐TAN treatment. Increases in glutamine and aspartate concentrations in H‐TAN fish suggest alterations in amino acid metabolism related to nitrogen excretion processes. Some of the changes in FAA concentrations also suggest mobilization to energy supply and synthesis of metabolites related to stress response. Therefore, Senegalese sole seem to adapt to the L‐TAN concentration tested, but the H‐TAN concentration reduced growth and affected amino acid metabolism. 相似文献
136.
Peter S. Solomon T. J. Greer Wilson Kasia Rybak Kerrie Parker Rohan G. T. Lowe Richard P. Oliver 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(3):275-282
The interaction between Stagonospora nodorum and a susceptible wheat cultivar was investigated using a range of microscopic techniques. Germination of pycnidiospores
occurred approximately 3 h after making contact with the leaf surface and was followed by attempted penetration 8–12 h later.
Penetration was observed through stomata and also directly through periclinal and anticlinal epidermal cell walls. Penetration
down the anticlinal cell walls appeared to occur without a differentiated penetrating structure whilst structures identified
as either lateral appressoria or hyphopodia were typically present when penetrating over a periclinal cell wall. Once inside
the leaf, the fungus continued to grow for the next 4–5 days colonising all parts of the leaf except the vascular bundles.
Only in the later phase of the infection was total host cell collapse apparent. Evidence of polyphenolic compounds was observed.
The infection cycle was completed within 7 days as indicated by sporulation on the leaf surface. These results have allowed
us to understand how the fungus physically interacts with the leaf and will help the overall understanding of the infection
process. 相似文献
137.
T L Huber M C Peed R C Wilson D D Goetsch 《American journal of veterinary research》1979,40(6):792-794
Absorption of endotoxin from the gastrointestinal tract was evaluated in hay-fed and lactic acidotic sheep duodenally infused with 10 mg of Escherichia coli endotoxin, and in lactic acidotic sheep not infused. The effect of abomasal fluid on biological activity of endotoxin was also evaluated. Leukopenia was the criterion used for detecting endotoxemia. Absorption of endotoxin from the gastrointestinal tract was not detected in either hay-fed or lactic acidotic sheep. Endotoxin appeared to maintain its activity after incubation with abomasal fluid, and the presence of endogenous endotoxin in abomasal contents was indicated. The results indicate that endotoxin of alimentary origin may not be involved in the lactic acidosis syndrome in ruminants. 相似文献
138.
T cell activation by lipopeptide antigens 总被引:2,自引:0,他引:2
Moody DB Young DC Cheng TY Rosat JP Roura-Mir C O'Connor PB Zajonc DM Walz A Miller MJ Levery SB Wilson IA Costello CE Brenner MB 《Science (New York, N.Y.)》2004,303(5657):527-531
Unlike major histocompatibility proteins, which bind peptides, CD1 proteins display lipid antigens to T cells. Here, we report that CD1a presents a family of previously unknown lipopeptides from Mycobacterium tuberculosis, named didehydroxymycobactins because of their structural relation to mycobactin siderophores. T cell activation was mediated by the alphabeta T cell receptors and was specific for structure of the acyl and peptidic components of these antigens. These studies identify a means of intracellular pathogen detection and identify lipopeptides as a biochemical class of antigens for T cells, which, like conventional peptides, have a potential for marked structural diversity. 相似文献
139.
Many specialist species are declining as a result of habitat loss and fragmentation, such that conservation actions typically aim to stem rates of decline rather than bring about genuine recovery. Here, we document the recovery of a species from former population refuges. An extensive survey of the entire British range of Hesperia comma, conducted in 2000, recorded over three times the number of tetrads (2 km × 2 km grid squares) occupied in 1982. This was accompanied by a fourfold increase in the number of populations and a 10-fold increase in the habitat area occupied. The improving status of H. comma is the product of good habitat management, recovering rabbit populations and climate warming, which have improved the quality, and increased the availability, of suitable habitat. This has enabled remnant metapopulations to expand, via distance-dependent colonisation, through large networks of habitat. Metapopulation recovery in H. comma demonstrates that landscape-scale conservation can be successful. 相似文献
140.
Noel E.A. Murphy Robert Loughman Robin Wilson Evans S. Lagudah Rudi Appels Michael G.K. Jones 《Euphytica》2000,113(3):227-231
Septoria nodorum blotch is the most important leaf disease of wheat in Western Australia. A potentially useful source of resistance
has been identified in an accession of Aegilops tauschii. To study the genetics of resistance of this source a cross was made between the resistant Ae. tauschii accession, RL5271, and a susceptible accession, CPI110889. The resistant parent took significantly longer to develop symptoms,
developed significantly fewer lesions and expressed significantly lower levels of disease than the susceptible parent. The
F1 mean response for disease severity indicated there was no complete dominance. The F3 families were classified using three
approaches. In the first approach the individual F3 plant response was used to classify the F3 families. In the second approach
the F3 family means and standard errors were used to classify the F3 families. In the final approach Best Linear Unbiased
Predictors of disease score and standard error for each F3 family derived from a REML analysis were used to classify the F3
families. The genotypic ratios generated by each of the approaches suggested that resistance is controlled by a single gene.
The effectiveness of the resistance and its simple genetic control in the Ae. tauschii, accession RL5271 may be a useful resistance source for use in a bread wheat breeding program.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献