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51.
Erik Jongedijk Henk Tigelaar Jeroen S. C. van Roekel Sandra A. Bres-Vloemans Ilma Dekker Peter J. M. van den Elzen Ben J. C. Cornelissen Leo S. Melchers 《Euphytica》1955,85(1-3):173-180
Summary Simultaneous expression of a tobacco class I chitinase and a class I -1,3-glucanase gene in tomato resulted in increased fungal resistance, whereas transgenic tomato plants expressing either one of these genes were not protected against fungal infection. After infection with Fusarium oxysporum f.sp. lycopersici, a 36% to 58% reduction in disease severity was observed in resistant tomato lines. Two transgenic lines largely recovered from the initial infection by the time wild-type tomato plants had died.The overall results are consistent with the observation that class I chitinases and class I -1,3-glucanases synergistically inhibit the growth of fungi in vitro and provide the first experimental support to the hypothesis that such synergy can contribute to enhanced fungal resistance in planta. 相似文献
52.
ABSTRACT: Polymerase chain reaction (PCR) restriction fragment length polymorphism analysis of mitochondrial DNA was applied to the genetic structure and evolutionary history of the more ancestral Pangasianodon hypophthalmus ( n = 82), and the recently speciated catfish Pangasius bocourti ( n = 90) from the Cambodian Mekong River. Both pangasiids were characterized by a lack of genetic population structure that may result from high levels of contemporary gene flow. Genetic diversity was lower in P. hypophthalmus than in P. bocourti . However, a different evolutionary history was inferred for both species based on genealogical and demographic analyses (mismatch analysis, Tajima's D- and Fu's F S -tests). The genetic profile of the more ancestral P. hypophthalmus shows indications of a recent population bottleneck, whereas the recently speciated P. bocourti shows signatures of historical population expansion. This study stresses the importance of preserving the migration routes in the Cambodian Mekong basin in order to maintain the genetic diversity and long-term integrity of both species. 相似文献
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Jeroen VosLinden Vincent 《Agricultural Water Management》2011,98(4):705-714
Volumetric water control (VWC) is widely seen as a means to increase productivity through flexible scheduling and user incentives to apply just enough water. However, the technical and social requirements for VWC are poorly understood. Also, many experts assert that VWC in large-scale open canals with many smallholders is not feasible. This article debates the practice of VWC, drawing on field studies in the arid North Coast of Peru. Here the large-scale Chancay-Lambayeque irrigation system achieved high allocation, distribution and financial performance with on demand delivery to some 22,000 smallholdings, under a VWC approach, with full cost recovery for operation and maintenance. This study shows there are options to promote VWC if its different elements - volumetric allocation, distribution, metering and pricing - are planned together. 相似文献
55.
Jordana M Wilderjans H Boswell J Dewulf J Smith RK Martens A 《Veterinary surgery : VS》2011,40(3):277-283
Objective: To report outcome after the surgical treatment of lacerations of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), suspensory ligament (SL), and/or distal sesamoidean ligaments (DSL) in horses. Study Design: Case series. Animals: Horses (n=106) with lacerations of the SDFT, DDFT, SL, and/or DSL. Methods: Medical records (1988–2002) were reviewed for signalment, limb and tendon/ligament involvement (location and extent of injury, tendon sheath involvement), method of repair, and outcome. Results: The median age of horses was 7 years and the follow‐up time ranged from 1 to 10 years. Fifty‐five percent of horses returned to their previous level of performance, 27% to a lower level, and 18% were euthanatized. Multivariate statistical analysis demonstrated that the number of structures transected had the most significant influence on outcome. No significant association was detected between outcome and tendon sheath involvement, tendon suturing, casting, or limb affected. Fetlock hyperextension was the most significant complication. Conclusions: A high survival rate can be expected after SDFT, DDFT, SL, and/or DSL lacerations in horses, but only 55% of affected horses returned to their previous activity level. The number of structures affected was the major factor determining whether horses returned to an equal level of performance. 相似文献
56.
Tom Meyns Jan Van Steelant Emily Rolly Jeroen Dewulf Freddy Haesebrouck Dominiek Maes 《Veterinary journal (London, England : 1997)》2011,187(3):388-392
A cross-sectional study was conducted to identify herd-level factors that may influence the prevalence and severity of macroscopically visible pulmonary lesions in pigs at slaughter. Data were collected following abattoir inspection of 50 randomly-selected batches of 6335 pigs and by interviewing the producers. Macroscopic lung lesions were identified and scored semi-quantitatively in ?80 pigs/herd and the prevalence of pleuritis and pneumonia was 20.76% and 23.85%, respectively. Following multivariable analysis, the seroprevalence of Actinobacillus pleuropneumoniae (P < 0.001) and Mycoplasma hyopneumoniae (P = 0.018) and the number of pigs/nursery pen (P = 0.023) were positively associated, whereas average weaning age was negatively associated (P = 0.001) with the pleuritis score. Risk factors associated with a higher prevalence of pneumonia were the presence of pleuritis (P = 0.001) and the frequent purchasing of pigs (P = 0.020). The findings of this study indicate that the prevalence of pleuritis and pneumonia remains high in Belgium and management factors are central to disease control. 相似文献
57.
Rienske A.R. Mortier Herman W. Barkema Karin Orsel Gregory P. Muench Janet M. Bystrom Oscar Illanes Jeroen De Buck 《The Canadian veterinary journal. La revue veterinaire canadienne》2015,56(12):1266-1270
Five calves were inoculated orally at 2 weeks of age with a dose of 5 × 109 colony-forming units of Mycobacterium avium subspecies paratuberculosis (MAP) on 2 consecutive days. Two calves developed clinical Johne’s disease at 12 and 16 months of age after being consistently positive for MAP on fecal culture and antibody enzyme-linked immunosorbent assay (ELISA), starting 2 to 3 weeks and 4 to 5 months after inoculation, respectively. 相似文献
58.
Fermented liquid feed is feed that has been mixed with water at a ratio ranging from 1:1.5 to 1:4. By mixing with water, lactic acid bacteria and yeasts naturally occurring in the feed proliferate and produce lactic acid, acetic acid and ethanol which reduces the pH of the mixture. This reduction in pH inhibits pathogenic organisms from developing in the feed. In addition, when this low pH mixture is fed, it reduces the pH in the stomach of pigs and prevents the proliferation of pathogens such as coliforms and Salmonella in the gastrointestinal tract. For piglets, the use of fermented liquid feed offers the possibility of simultaneously providing feed and water, which may facilitate an easier transition from sow’s milk to solid feed. Secondly, offering properly produced fermented liquid feed may strengthen the role of the stomach as the first line of defense against possible pathogenic infections by lowering the pH in the gastrointestinal tract thereby helping to exclude enteropathogens. Finally, feeding fermented liquid feed to pigs has been shown to improve the performance of suckling pigs, weaner pigs and growing-finishing pigs. In this review, current knowledge about the use of fermented liquid feed in pig diets will be discussed. This will include a discussion of the desirable properties of fermented liquid feed and factors affecting fermentation. In addition, advantages and disadvantages of fermented liquid feed will be discussed including its effects on gastrointestinal health, intestinal pH and the types of bacteria found in the gastrointestinal tract as well as the effects of fermented liquid feeds on pig performance. 相似文献
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Aten JA Stap J Krawczyk PM van Oven CH Hoebe RA Essers J Kanaar R 《Science (New York, N.Y.)》2004,303(5654):92-95
Interactions between ends from different DNA double-strand breaks (DSBs) can produce tumorigenic chromosome translocations. Two theories for the juxta-position of DSBs in translocations, the static "contact-first" and the dynamic "breakage-first" theory, differ fundamentally in their requirement for DSB mobility. To determine whether or not DSB-containing chromosome domains are mobile and can interact, we introduced linear tracks of DSBs in nuclei. We observed changes in track morphology within minutes after DSB induction, indicating movement of the domains. In a subpopulation of cells, the domains clustered. Juxtaposition of different DSB-containing chromosome domains through clustering, which was most extensive in G1 phase cells, suggests an adhesion process in which we implicate the Mre11 complex. Our results support the breakage-first theory to explain the origin of chromosomal translocations. 相似文献