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Bacterial blood culture results of 292 privately owned cats presented to the Clinic for Small Animal Medicine, Ludwig Maximilian University Munich with signs of sepsis were evaluated retrospectively. Of the blood cultures, 23% were positive. In 88%, a single bacterial species was isolated. Of all bacterial isolates, 45% were Gram-positive, 43% were Gram-negative, and 12% were obligate anaerobes. The most frequently isolated bacteria were Enterobacteriaceae, obligate anaerobic species, Staphylococcus species and Streptococcus species. Of the cats with positive blood cultures, 32% were pretreated with antibiotics. Of all bacterial isolates, 77% were susceptible to enrofloxacin, 69% to chloramphenicol, 67% to gentamicin, and 64% to amoxycillin clavulanic acid. Only enrofloxacin reached an in vitro efficacy of more than 70% against Gram-positive and more than 74% against Gram-negative bacteria. 相似文献
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Tappeiner Ulrike Leitinger Georg Zariņa Anita Bürgi Matthias 《Landscape Ecology》2021,36(8):2317-2328
Landscape Ecology - Landscape ecology early on developed the awareness that central objects of investigation are not stable over time and therefore the historical dimension must be included, or at... 相似文献
4.
Philippe Desbordes Bernd Essigmann Stephanie Gary Oliver Gutbrod Michael Maue Hans‐Georg Schwarz 《Pest management science》2020,76(10):3340-3347
Succinate dehydrogenase inhibitors (SDHIs) have played a crucial role in disease control to protect cereals as well as fruit and vegetables for more than a decade. Isoflucypram, the first representative of a newly installed subclass of SDHIs inside the Fungicide Resistance Action Committee (FRAC) family of complex II inhibitors, offers unparalleled long‐lasting efficacy against major foliar diseases in cereals. Herein we report the chemical optimization from early discovery towards isoflucypram and the first hypothesis of its altered binding mode in the ubiquinone binding site of succinate dehydrogenase. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献
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Nodulation and root growth increase in lower soil layers of water‐limited faba bean intercropped with wheat 下载免费PDF全文
Below‐ground niche complementarity in legume–cereal intercrops may improve resource use efficiency and root adaptability to environmental constraints. However, the effect of water limitation on legume rooting and nodulation patterns in intercropping is poorly understood. To advance our knowledge of mechanisms involved in water‐limitation response, faba bean (Vicia faba L.) and wheat (Triticum aestivum L.) were grown as mono‐ and intercrops in soil‐filled plexiglass rhizoboxes under water sufficiency (80% of water‐holding capacity) and water limitation (30% of water‐holding capacity). We examined whether intercropping facilitates below‐ground niche complementarity under water limitation via interspecific root stratification coupled with modified nodulation patterns. While no significant treatment effects were measured in intercropped wheat growth parameters, water limitation induced a decrease in shoot and root biomass of monocropped wheat. Likewise, shoot biomass and height, and root length of monocropped faba bean significantly decreased under water limitation. Conversely, water limitation stimulated root biomass of intercropped faba bean in the lower soil layer (15–30 cm soil depth). Similarly, total nodule number of faba bean roots as well as nodule number in the lower soil layer increased under intercropping regardless of water availability. Under water limitation, intercropping also led to a significant increased nodule biomass (48%) in the lower soil layer as compared to monocropping. The enhanced nodulation in the lower soil layer and the associated increase in root and shoot growth provides evidence for a shift in niche occupancy when intercropped with wheat, which improves water‐limited faba bean performance. 相似文献
7.
Khalid S. Khan Andreas Gattinger Franz Buegger Michael Schloter Rainer Georg Joergensen 《Soil biology & biochemistry》2008,40(5):1217-1224
An incubation experiment was carried out to investigate whether salinity at high pH has negative effects on microbial substrate use, i.e. the mineralization of the amendment to CO2 and inorganic N and the incorporation of amendment C into microbial biomass C. In order to exploit natural differences in the 13C/12C ratio, substrate from two C4 plants, i.e. highly decomposed and N-rich sugarcane filter cake and less decomposed N-poor maize leaf straw, were added to two alkaline Pakistani soils differing in salinity, which had previously been cultivated with C3 plants. In soil 1, the additional CO2 evolution was equivalent to 65% of the added amount in the maize straw treatment and to 35% in the filter cake treatment. In the more saline soil 2, the respective figures were 56% and 32%. The maize straw amendment led to an identical immobilization of approximately 48 μg N g−1 soil over the 56-day incubation in both soils compared with the control soils. In the filter cake treatment, the amount of inorganic N immobilized was 8.5 μg N g−1 higher in soil 1 than in soil 2 compared with the control soils. In the control treatment, the content of microbial biomass C3-C in soil 1 was twice that in soil 2 throughout the incubation. This fraction declined by about 30% during the incubation in both soils. The two amendments replaced initially similar absolute amounts of the autochthonous microbial biomass C, i.e. 50% of the original microbial biomass C in soil 1 and almost 90% in soil 2. The highest contents of microbial biomass C4-C were equivalent to 7% (filter cake) and 11% (maize straw) of the added C. In soil 2, the corresponding values were 14% lower. Increasing salinity had no direct negative effects on microbial substrate use in the present two soils. Consequently, the differences in soil microbial biomass contents are most likely caused indirectly by salinity-induced reduction in plant growth rather than directly by negative effects of salinity on soil microorganisms. 相似文献
8.
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
9.
Nitrogen inputs from biological nitrogen fixation contribute to productivity and sustainability of agroforestry systems but
they need to be able to offset export of N when trees are harvested. This study assessed magnitudes of biological nitrogen
fixation (natural 15N abundance) and N balance of Acacia mangium woodlots grown in farmer’s fields, and determined if N2 fixation capacity was affected by tree age. Tree biomass, standing litter, understory vegetation and soil samplings were
conducted in 15 farmer’s fields growing A. mangium as a form of sequential agroforestry in Claveria, Misamis Oriental, Philippines. The trees corresponded to ages of 4, 6,
8, 10 and 12 years, and were replicated three times. Samples from different plant parts and soils (0–100 cm) were collected
and analyzed for δ15N and nutrients. The B-value, needed as a reference of isotopic discrimination when fully reliant on atmospheric N, was generated by growing A. mangium in an N2-free sand culture in the glasshouse. Isotopic discrimination occurring during N2 fixation and metabolic processes indicated variation of δ15N values in the order of nodules > old leaves > young leaves > stems > litterfall and roots of the trees grown in the field,
with values ranging from −0.8 to 3.5‰ except nodules which were enriched and significantly different from other plant parts
(P < 0.0001). Isotopic discrimination was not affected by tree age (P > 0.05). Plants grown in N free sand culture exhibited the same pattern of isotopic discrimination as plants grown in the
field. The estimated B-value for the whole plant of A. mangium was −0.86‰. Mature tree stands of 12 years accumulated up to 1994 kg N ha−1 in aboveground biomass. Average proportion of N derived from N2 fixation of A. mangium was 54% (±22) and was not affected by age (P > 0.05). Average yearly quantities of N2 fixed were 128 kg N ha−1 in above-ground biomass amounting to 1208 kg N fixed ha−1 over 12 years. Harvest of 12-year old trees removed approximately 91% of standing aboveground biomass from the site as timber
and fuel wood. The resulting net N balance was +151 kg N ha−1 derived from remaining leaves, twigs, standing litter, and +562 kg N ha−1 when tree roots were included in the calculation. The fast growing A. mangium appears to be a viable fallow option for managing N in these systems. However, other nutrients have to be replaced by using
part of the timber and fuel wood sales to compensate for large amounts of nutrient removed in order for the system to be sustainable. 相似文献
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