Veterinarians’ perspective on a voluntary Johne’s disease prevention program in Ontario and western Canada     

Ulrike S. Sorge  Jeremy Mount  David F. Kelton  Ann Godkin 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(4):403-405

A survey was conducted to assess the beliefs of veterinarians on Johne’s disease (JD) and their attitudes towards the Canadian, risk assessment based, JD prevention program. The veterinarians surveyed believed Mycobacterium avium subsp. paratuberculosis may have zoonotic potential, liked the risk assessment based program, and thought it could lead to the prevention of other on-farm diseases.  相似文献   

Effect of fungicides on the complex of <Emphasis Type="Italic">Fusarium</Emphasis> species and saprophytic fungi colonizing wheat kernels     

Carmen Müllenborn  Ulrike Steiner  Michael Ludwig  Erich-Christian Oerke 《European journal of plant pathology / European Foundation for Plant Pathology》2008,120(2):157-166

Fusarium head blight of wheat, often associated with mycotoxin contamination of food and feed is caused by various Fusarium species. The efficacy of fungicide sprays for the control of the disease and mycotoxins varies from being highly effective to even increasing mycotoxin levels. The potential role of antagonistic fungi in this variability was investigated assessing sensitivity of Fusarium species and saprophytic fungi colonizing wheat kernels to fungicides. Saprophytes were tested for their antagonistic activity to the prevalent Fusarium species Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, and Fusarium poae. Fungal isolates from mature winter wheat kernels were Alternaria alternata, Arthrinium sp., Aspergillus niger, Epicoccum sp., Microdochium spp., Rhizopus oryzae and Trichoderma sp. In dual culture A. niger, R. oryzae and Trichoderma hamatum were more effective in reducing mycelial growth of Fusarium species than Microdochium majus; A. alternata and Epicoccum sp. were ineffective because of slow growth rates. Saprophytic fungi were sensitive to triazoles; however, prothioconazole and tebuconazole had stronger effects on mycelial growth of Fusarium species. ED₅₀ values also indicated significant differences in the sensitivity of Fusarium species to triazoles (range 0.1–1.7 mg l⁻¹). Azoxystrobin and fluoxastrobin were largely ineffective in inhibiting in vitro growth of Fusarium spp.; sensitivity of the other fungi was generally lower, except for M. majus which was highly sensitive. Due to differences in fungicide sensitivity among Fusarium spp. and ear-colonizing fungi antagonistic to Fusarium spp. fungicides are likely to modify the balance within the mycoflora of wheat ears which may also affect the mycotoxin contamination of grain.  相似文献   

Report on the 42nd joint meeting of the DPG-working group Nematology and the working group “free living nematodes”     

Daub  Matthias  Hakl  Ulrike  Maressa  Beira Hailu  Dehne  Heinz-Wilhelm  Hallmann  Johannes  Kiewnick  Sebastian  Eberlein  Caroline  Heuer  Holger  Moos  Jan H  Paulsen  Hans M  Westphal  Andreas  Sturhan  Dieter  Kiewnick  Sebastian  Wolf  Stefanie  Bühlmann  Andy  Frey  Jürg  Nuaima  Rasha  Heuer  Holger  Westphal  Andreas 《植物病害和植物保护杂志》2014,121(4):187-189

Journal of Plant Diseases and Protection -  相似文献   

Immunohistochemical investigation of Foxp3 expression in the intestine in healthy and diseased dogs     

Junginger J  Schwittlick U  Lemensieck F  Nolte I  Hewicker-Trautwein M 《Veterinary research》2012,43(1):23

ABSTRACT: Intestinal immune regulation including development of oral tolerance is of great importance for the maintenance of intestinal homeostasis. Concerning this, regulatory T cells (Tregs) occupy a pivotal role in cell-mediated immunosuppression. Dysregulation of mucosal immunology leading to an abnormal interaction with commensal bacteria is suggested to play a key role in the pathogenesis of Inflammatory Bowel Disease (IBD) in men and dogs. The aim of this study was to characterise the expression of Foxp3 in the normal canine gut of 18 dogs (mean age: 6.03 years), in 16 dogs suffering from IBD (mean age: 5.05 years), and of 6 dogs with intestinal nematode infection (mean age: 0.87 years) using immunohistochemistry. In the duodenum, Tregs in healthy dogs declined from villi (median: 10.67/62 500 μm2) to crypts (median: 1.89/62 500 μm2). Tregs were further increased in the villi of middle-aged dogs (median: 18.92/62 500 μm2) in contrast to juvenile (median: 3.50/62 500 μm2) and old (median: 9.56/62 500 μm2) individuals. Compared to healthy controls, animals suffering from IBD revealed reduced numbers of Tregs in duodenal villi (median: 4.13/62 500 μm2). Dogs with intestinal nematode infection displayed increased numbers of Tregs (median: 21.06/62 500 μm2) compared to healthy animals.Age-related changes indicate a progressive establishment of oral tolerance and immunosenescence in the canine elderly. The results further suggest that a defect in Treg homeostasis may be involved in the pathogenesis of canine IBD. In contrast, increased numbers of Tregs in the duodenum may be due to nematode infection.  相似文献   

Effect of elevated CO₂ on soil N dynamics in a temperate grassland soil     

Christoph Müller  Tobias Rütting  M. Kaleem Abbasi  Ronald J. Laughlin  Claudia Kammann  Tim J. Clough  Robert R. Sherlock  Jens Kattge  Hans-Jürgen Jger  Catherine J. Watson  R. James Stevens 《Soil biology & biochemistry》2009,41(9):1996-2001

The response of terrestrial ecosystems to elevated atmospheric CO₂ is related to the availability of other nutrients and in particular to nitrogen (N). Here we present results on soil N transformation dynamics from a N-limited temperate grassland that had been under Free Air CO₂ Enrichment (FACE) for six years. A ¹⁵N labelling laboratory study (i.e. in absence of plant N uptake) was carried out to identify the effect of elevated CO₂ on gross soil N transformations. The simultaneous gross N transformation rates in the soil were analyzed with a ¹⁵N tracing model which considered mineralization of two soil organic matter (SOM) pools, included nitrification from NH₄⁺ and from organic-N to NO₃⁻ and analysed the rate of dissimilatory NO₃⁻ reduction to NH₄⁺ (DNRA). Results indicate that the mineralization of labile organic-N became more important under elevated CO₂. At the same time the gross rate of NH₄⁺ immobilization increased by 20%, while NH₄⁺ oxidation to NO₃⁻ was reduced by 25% under elevated CO₂. The NO₃⁻ dynamics under elevated CO₂ were characterized by a 52% increase in NO₃⁻ immobilization and a 141% increase in the DNRA rate, while NO₃⁻ production via heterotrophic nitrification was reduced to almost zero. The increased turnover of the NH₄⁺ pool, combined with the increased DNRA rate provided an indication that the available N in the grassland soil may gradually shift towards NH₄⁺ under elevated CO₂. The advantage of such a shift is that NH₄⁺ is less prone to N losses, which may increase the N retention and N use efficiency in the grassland ecosystem under elevated CO₂.  相似文献   

Stimulation of methane consumption by endogenous CH₄ production in aerobic grassland soil     

Claudia Kammann  Simone Hepp  Christoph Müller 《Soil biology & biochemistry》2009,41(3):622-629

The net CH₄ flux in terrestrial ecosystems is mostly the result of simultaneous gross CH₄ production (P₄CH) and gross CH₄ consumption (C₄CH) rates. However, it is not well-understood how endogenous P₄CH may influence C₄CH and hence the net CH₄ flux outcome in upland soils. Gross CH₄ consumption may be either stimulated or outweighed by P₄CH, resulting in higher or lower net CH₄ uptake rates, respectively. To investigate gross CH₄ fluxes, we incubated intact soil cores taken from a permanent grassland with and without difluoromethane (DFM; blocks CH₄ oxidation). The gross CH₄ consumption was calculated by taking the DFM-measured rate of P₄CH into account. Most of the oxic cores exhibited a more than 30 times higher C₄CH than P₄CH rate. However, four cores showed a considerably higher gross CH₄ production, accompanied by a stimulated gross CH₄ uptake which was entirely masked in the net CH₄ flux (C₄CH/P₄CH ratios of 0.9-2.3). In three of the four cores macro-fauna (earthworms and Scarab beetle larvae) were present. Removing the animals and homogenizing the intact core structure lowered P₄CH by 27-100%. Subsequent incubation of Scarabidae larvae such as Pachnoda sp., Cetonia sp. and others revealed animal CH₄ and N₂O production rates within the range of those observed in the inhabited cores. Moreover, in-situ soil air CH₄ concentrations obtained from four depth profiles (0-50 cm depth) at the grassland site also indicated that temporarily, small-scale local hot spots of CH₄ and N₂O production existed within otherwise aerobic soil profiles. These spots indicated a stimulated CH₄ uptake after the CH₄ source (of whatever nature) had ceased. The results suggest that soil macro-fauna, anaerobic soil microsites or both combined may provide suitable conditions for CH₄ production in otherwise oxic soil environments. Hence, endogenous CH₄ production in upland soil may partially be related to the density and species composition of soil invertebrates, with a potential impact on the CH₄ sink capacity of these soils.  相似文献   

In search for the ecological and toxicological relevance of sediment re-mobilisation and transport during flood events   总被引：3，自引：2，他引：1  

Jan Wölz  Catrina Cofalla  Sebastian Hudjetz  Sebastian Roger  Markus Brinkmann  Burkhard Schmidt  Andreas Schäffer  Ulrike Kammann  Gottfried Lennartz  Markus Hecker  Holger Schüttrumpf  Henner Hollert 《Journal of Soils and Sediments》2009,9(1):1-5

In response to increasing concerns about the potential toxicological impacts of (extreme) flood events, scientists from several disciplines have joined to form the interdisciplinary research project named FLOODSEARCH. FLOODSEARCH is one of the recent Pathfinder Projects supported by the German Excellence Initiative via the Exploratory Research Space at RWTH Aachen (ERS). FLOODSEARCH aims to combine methodologies of hydraulic engineering and ecotoxicology in a new interdisciplinary approach to assess the risks associated with the re-mobilisation of particulate bound contaminants often observed after severe flood events. Impacts of extreme flood events and aspects of re-mobilisation of sediment-bound toxic compounds will be characterised and evaluated in controlled experiments fusing flood simulation technologies with biological effects assessment. The overall goal is to establish a novel and more realistic approach towards flood event testing that can be applied to a number of different questions and species. Specifically, model aquatic species such as rainbow trout (Onchorhynchus mykiss) will be exposed to particle-bound contaminants in flood-like conditions in a specifically designed annular flume that permits monitoring of both physical/chemical and biological parameter. Ultimately, this approach will assist to further our understanding of the potential biological risks associated with increasingly frequent extreme flood events, e.g., as a consequence of climate change, by bridging the gap between the physical (re-)mobilisation of contaminants and resulting toxicological impacts on aquatic organisms. Thus, it is the objective of the project to derive relationships between the hydrodynamic parameters such as velocities and turbulences, the parameters associated to sediment transport such as sediment concentration and grain sizes and the biological parameters.  相似文献   

Primed N2O emission from native soil nitrogen: A 15N‐tracing laboratory experiment          下载免费PDF全文

Philipp Schleusner  Carlo Lammirato  Jens Tierling  Ulrike Lebender  Tobias Rütting 《植物养料与土壤学杂志》2018,181(4):621-627

Soils can naturally be a source of the potent greenhouse gas nitrous oxide (N₂O). By contrast, the largest anthropogenic source of N₂O is the application of nitrogen (N) fertilizer on agricultural soil, but it is unclear if fertilizer‐supported N₂O emission only originates from the fertilizer N directly or through additionally stimulated N₂O production from native soil N. Even though native soil N also includes mineral N already in soil before fertilizer application, organic N is the principal native N pool and thereby provides for mineral N cycling and N₂O emission. Here, we tested (1) the contribution of native soil N to N₂O emission after mineral N fertilizer application and (2) whether it is affected by different soil organic matter (SOM) contents by conducting a laboratory ¹⁵N‐tracing experiment with agricultural soil from a long‐term field trial with two treatments. Both field treatments are fertilized with mineral N, whereas only one of the two receives liquid manure causing higher SOM content. Soil sampling was conducted in March 2016 shortly before fertilizer application in the field. The application of ¹⁵N‐labeled fertilizer more than doubled the N₂O production from native N sources compared to the non‐fertilized control incubations. This primed N₂O production contributed by 5–8% to the fertilizer‐induced N₂O emission after one week of incubation and was similar for both field treatments regardless of liquid manure application. Therefore, further research is needed to link N₂O priming to its potential production pathways and sources. While the observed effect may be important in soils, the amount of applied N fertilizer remains the largest concern being responsible for the majority of N₂O emission.  相似文献   

Sind Pollenspritzungen oder Pollendispenser Alternativen zur herkömmlichen Bestäubung der Apfelbäume durch Bienen?     

Ulrike Kubersky  O. Boecking  D. Wittmann 《Erwerbs-Obstbau》2005,47(5):117-123

The efficacy of different methods of applying cv. ‘Golden Delicious‘ pollen to ‘Cox Orange‘ apple trees inside insect-proof cages was investigated: (1) spraying pollen suspended in water directly into the trees while they were in bloom (treatment A); (2) pollen transfer by honeybees (treatment B) or by bumblebees (treatment C), both of which had to pass through a dispenser loaded with cv. ‘Golden Delicious‘ pollen; (3) transfer by honeybees of pollen from cv ‘Golden Delicious‘ trees bearing compatible pollen and maintained in pots within the same cages (treatment D). Naturally pollinated cv. ‘Cox Orange‘ apple trees outside the cages in the orchard served as controls. For methods A–C normal commercially available ‘Golden Delicious‘ pollen was used for hand pollination, and its efficacy was assessed with reference to the amount of fruit that set. The fruit-set at the time of harvesting differed significantly (Nemenyi test) with the different methods of pollination: 1.0% (±2.0) of the blossoms ripened to yield marketable apples after treatment A, 6.1% (±5.2) after treatment B, 4.9% (±4.6) after treatment C, and 20.4% (±11.5) after treatment D, while the corresponding figure for the control trees was 7.3% (±2.8) and that for hand pollination, 41,9%. The low fruit-set after an aqueous suspension of cv. ‘Golden Delicious‘ pollen was sprayed on the test trees shows that this procedure did not result in adequate pollination. The density of pollen grains was determined on filter papers during spraying and was an average of 3 (±2.6, range 0.0–8.6) pollen grains/cm². When the pollen dispensers were used, the fruit-set was lower than on the hand-pollinated control trees. Despite the success of manual pollination with exogenous cv. ‘Golden Delicious‘ pollen, pollen spraying to enhance pollination, as specified in current instructions, cannot be recommended for commercial apple growing in Germany.  相似文献   

Extended summaries sci pesticides group symposium biological control: Use of living organisms in the management of invertebrate pests,pathogens and weeds.     

Birgit Krebs  Helmut Junge  Andrea Ockhardt  Birgit Hoding  Dagmar Heubner  Ulrike Erben 《Pest management science》1993,37(4):427-429

The following are extended summaries based on material presented at a meeting of the SCI Pesticides Group, held on 19-20 October 1992 at the SCI, 14/15 Belgrave Square, London SWIX 8PS, UK. The summaries published here are entirely the responsibility of the authors and do not necessarily reflect the views of the Editorial Board of Pesticide Science.  相似文献