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排序方式: 共有298条查询结果,搜索用时 15 毫秒
1.
Patrick Rehmann Andrea Gr?ne Bruno Gottstein Jürg V?llm Heinz Sager Martin Janovsky Luca N Bacciarini 《Journal of veterinary diagnostic investigation》2005,17(2):183-186
Five animals in a colony of cynomolgus monkeys (Macaca fascicularis) died or were euthanatized because of alveolar echinococcosis, during a period of 5 years. The remainder of the colony was screened for possible infection with Echinococcus multilocularis, using serology and ultrasonography. A total of 46 animals out of a group of 55 were examined. The presence of anti-Em2 antibodies analyzed with enzyme-linked immunosorbent assay was demonstrated in 3 monkeys. In 2 of these 3 monkeys, multilocular structures compatible with metacestodal cysts in the liver were identified, using ultrasonography. The presence of alveolar echinococcosis was subsequently confirmed at postmortem examination in 1 animal. The other animals are still alive. Two other monkeys were negative in the serological examination but had cystic structures in the liver, which were identified as bile duct cysts at postmortem examination in 1 animal. The other monkey is still alive. These findings suggest that serology for antibodies against the Em2 antigen may represent a useful method in identifying animals that might be infected with E. multilocularis and are therefore at risk of developing fatal alveolar echinococcosis. 相似文献
2.
Environmental effects on soil NO concentrations and root N uptake in beech and spruce forests 下载免费PDF全文
Fang Dong Judy Simon Michael Rienks Jürgen Schäffer Klaus von Wilpert Heinz Rennenberg 《植物养料与土壤学杂志》2016,179(2):244-256
This study aimed to investigate the shifts in net nitrogen (N) uptake and N compounds of fine roots over the vegetation period (i.e., spring, summer, autumn) and correlate this with NO concentration in the soil. Soil NO concentration was measured using gas lysimeters for collection and a chemiluminescence analyzer for quantification. Net N uptake by the roots was determined using the 15N enrichment technique. N pools were quantified using spectrophotometric techniques. Soil NO concentrations at beech and spruce forest sites were highest in spring (June), and lowest in winter (December). Total N of the roots was similar during the seasons and between the two years under study despite considerable variation of different N compounds. Net N uptake generally increased with higher N supply. Correlation analysis revealed a positive relationship between soil NO concentration and net N uptake only for spruce trees. This relationship seemed to be modulated by environmental factors and tree species. 相似文献
3.
Tetracyclines are widely used in farm animals. This can cause drug residues in products of animal origin and, after excretion of these substances, in animal slurry and in soil fertilized with that slurry. In this paper, we present a method based on a microbiological assay coupled with HPLC for the detection of oxytetracycline, tetracycline, and chlortetracycline in eggs. After a simple liquid extraction of the samples and HPLC separation, fractions were collected on microtiter plates, and the tetracyclines were analyzed using the Staphylococcus aureus assay. This method was able to identify residues of tetracyclines in eggs at a level set by regulatory agencies (i.e., 200 microg/kg). In addition, it was shown that the described microbiological method can be used as a screening assay for the detection of tetracyclines and possible biologically active metabolites in animal slurry and soil samples. Employing the same extraction procedure, it was demonstrated that LC-MS-MS allowed the quantification of 20-400 microg/kg in eggs with recoveries ranging from 71 to 109% and RSDs of 3-15%. 相似文献
4.
Stabilization mechanisms of organic matter in four temperate soils: Development and application of a conceptual model 总被引:2,自引:0,他引:2
Margit von Lützow Ingrid Kögel‐Knabner Bernard Ludwig Egbert Matzner Heinz Flessa Klemens Ekschmitt Georg Guggenberger Bernd Marschner Karsten Kalbitz 《植物养料与土壤学杂志》2008,171(1):111-124
Based on recent findings in the literature, we developed a process‐oriented conceptual model that integrates all three process groups of organic matter (OM) stabilization in soils namely (1) selective preservation of recalcitrant compounds, (2) spatial inaccessibility to decomposer organisms, and (3) interactions of OM with minerals and metal ions. The model concept relates the diverse stabilization mechanisms to active, intermediate, and passive pools. The formation of the passive pool is regarded as hierarchical structured co‐action of various processes that are active under specific pedogenetic conditions. To evaluate the model, we used data of pool sizes and turnover times of soil OM fractions from horizons of two acid forest and two agricultural soils. Selective preservation of recalcitrant compounds is relevant in the active pool and particularly in soil horizons with high C contents. Biogenic aggregation preserves OM in the intermediate pool and is limited to topsoil horizons. Spatial inaccessibility due to the occlusion of OM in clay microstructures and due to the formation of hydrophobic surfaces stabilizes OM in the passive pool. If present, charcoal contributes to the passive pool mainly in topsoil horizons. The importance of organo‐mineral interactions for OM stabilization in the passive pool is well‐known and increases with soil depth. Hydrophobicity is particularly relevant in acid soils and in soils with considerable inputs of charcoal. We conclude that the stabilization potentials of soils are site‐ and horizon‐specific. Furthermore, management affects key stabilization mechanisms. Tillage increases the importance of organo‐mineral interactions for OM stabilization, and in Ap horizons with high microbial activity and C turnover, organo‐mineral interactions can contribute to OM stabilization in the intermediate pool. The application of our model showed that we need a better understanding of processes causing spatial inaccessibility of OM to decomposers in the passive pool. 相似文献
5.
Mark K. Sears Cindy Bowhey Heinz Braun Gerald R. Stephenson 《Pest management science》1987,20(3):223-231
In laboratory experiments, residues of diazinon applied to turfgrass, Poa pratensis L., that could be dislodged by rubbing with cheese-cloth, declined from c. 10% of the total applied when the grass was vigorously rubbed immediately after application to 0.3% after 1 day. Sunlight did not influence the rate of decline in dislodgeable residues or residues remaining on or within the leaf blades. In field experiments where 4.5 kg ha?1 of diazinon was applied in liquid or granular form, about 20 times more diazinon was dislodged from the liquid formulation immediately after application than from the granular. By 1 day after application the percentage of the total applied diazinon that could be dislodged was equal for both formulations. Rainfall had a significant effect on the amount dislodged from grass blades, but mowing did not. Similar rates of decline in the dislodgeable fraction of diazinon, chlorpyrifos and isofenphos were observed in field experiments. Recovery of the dislodgeable fraction declined to 0.25% or less of the total amount of any of these insecticides by 1 day after application. However, residues in the thatch remained sufficiently high for control of insects for up to 7 days after application for diazinon and 14 days for chlorpyrifos and isofenphos. 相似文献
6.
Alfons Pascual Alfred Rindlisbacher Heinz Schmidli Erich Stamm 《Pest management science》1995,44(4):369-379
The biological activity of a series of N-(pyrid-3-yl)thioureas and -carbodiimides, analogues of the insecticide/acaricide diafenthiuron, towards the carmine spider mite (Tetranychus cinnabarinus Boisd.) and the two-spotted spider mite (T. urticae Koch) was analysed using QSAR methodology. A canonical correlation analysis allowed for the establishment of a prediction model and the identification of outliers within that model. The chemodynamic behaviour of certain compounds in the two series, including these outliers, determined by using photochemical experiments in the laboratory as well as in the glasshouse, was shown to be responsible for anomalous results obtained in the biological tests. It was found from the above study that the biological activity towards both spider mite species is extremely sensitive to the kinetics of formation of the carbodiimides from the corresponding thioureas and to the photostability of the former. The results obtained with a thiourea which underwent no appreciable photochemical transformation into the corresponding carbodiimide supported the hypothesis that the thioureas are also in-vivo propesticides of the acaricidal carbodiimides. 相似文献
7.
Lahrmann KH Steinberg C Dahms S Heller P 《Berliner und Münchener tier?rztliche Wochenschrift》2003,116(1-2):67-73
A longitudinal observational study in 180 pig breeding herds was performed to calculate prevalences of herd specific factors as well as typical limb disorders and to estimate their associations in a 2-step regression analysis. Regarding herd size, genetics, feeding and weight gain herds were distributed almost equal. The population density and the hygiene status were considered proper in most herds. In the farrowing units partially slatted floors of metal or plastic with slats > 9 mm, in the weaning units fully slatted floors of plastic, and in the rearing units fully slatted floors of concrete were most common. Less than 6% of the farms housed their pigs on solid concrete with straw bedding. Herd prevalences of fault floors varied between 18 and 43%. As a herd health problem (morbidity > 25%) claw hematomas and limb abrasions in just 1-week old piglets, overgrown claws and bursa swellings in weaned pigs, and bursa swellings in rearing pigs were wide spread. Leg deformations by osteopathy or arthritis occurred only sporadically. In the risk analysis claw hematomas of piglets were associated with slatted floors, particulary with slats < 10 mm. Abrasions were associated with concrete and rough floor surfaces at all. Overgrown claws and bursa swellings in weaned and in rearing pigs were associated with damaged, slippery or rough floor surfaces. Other associations were not detected. The quality of floor might be more important than the type of housing. 相似文献
8.
9.
R Heinz S.W Lee A Saparno R.N Nazar J Robb 《Physiological and Molecular Plant Pathology》1998,52(6):385-396
It is generally believed thatVerticilliummoves slowly up a plant through spore trapping sites in the vascular tissue in a stepwise fashion. In a resistant plant, rapid defence responses around these sites slow pathogen growth and often restrict the fungus to the root and stem base. In a susceptible plant, the fungus escapes and eventually proliferates logarithmically in the upper stem and leaves. In the present study Craigella tomatoes were infected withVerticillium albo-atrum. Amounts of pathogen were monitored in the upper stems by a PCR-based quantitative assay and S1nuclease protection was used to study expression of a fungal induced phenylalanine ammonia lyase gene (tPAL5) during a 2–21 day time course. Even in resistant plants fungal colonization and PAL gene expression were found to be fully systemic from the earliest sporulation events (i.e. 2–4 days post-inoculation) and to occur in cycles, the PAL gene cycle following the colonization cycle. Peaks of pathogen growth occurred at 2–4 days and 12–15 days, succeeded by intermittent periods of fungal elimination. The results indicated that wilt is more systemic and also more dynamic in terms of fungal population fluctuations than previously thought. 相似文献
10.