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排序方式: 共有162条查询结果,搜索用时 390 毫秒
71.
Nadine A. Vogt David L. Pearl Eduardo N. Taboada Richard J. Reid‐Smith Michael R. Mulvey Nicol Janecko Steven K. Mutschall Claire M. Jardine 《Zoonoses and public health》2019,66(1):60-72
From May through October 2016, we conducted a repeated cross‐sectional study examining the effects of temporal, spatial, flock and demographic factors (i.e. juvenile vs. adult) on the prevalence of Campylobacter and antimicrobial resistant Enterobacteriaceae among 344 fresh faecal samples collected from Canada geese (Branta canadensis) from four locations where birds nested in Guelph, Ontario, Canada. The overall prevalence of Campylobacter among all fresh faecal samples was 9.3% and was greatest in the fall when these birds became more mobile following the nesting season. Based on 40 gene comparative genomic fingerprinting (CGF40), the increase in prevalence noted in the fall was matched by an increase in the number of unique CGF40 subtypes identified. Resistance to colistin was detected most commonly, in 6% of Escherichia coli isolates, and was highest in the late summer months. All colistin‐resistant isolates were negative for the mcr‐1 to mcr‐5 genes; a chromosomal resistance mechanism (PmrB) was identified in all of these isolates. The prevalence of samples with E. coli exhibiting multi‐class resistance or extended spectrum beta‐lactamase was low (i.e. <2% of samples). The intra‐class correlation coefficients, estimated from the variance components of multilevel logistic regression models, indicated that the shedding of Campylobacter and antimicrobial resistant E. coli among geese within a flock (i.e. birds collected from the same site on the same day) was moderately correlated. Spatial, temporal, and spatiotemporal clusters identified using the spatial scan statistic, largely supported the findings from our multi‐level models. Salmonella was not isolated from any of the fresh faecal samples collected suggesting that its prevalence in this population of birds was very low. 相似文献
72.
M. Candolfi F. Bigler P. Campbell U. Heimbach R. Schmuck G. Angeli F. Bakker K. Brown G. Carli A. Dinter D. Forti R. Forster A. Gathmann S. Hassan M. Mead-Briggs M. Melandri P. Neumann E. Pasqualini W. Powell J. -N. Reboulet K. Romijn B. Sechser Th. Thieme A. Ufer Ch. Vergnet H. Vogt 《Journal of pest science》2000,73(6):141-147
This paper is a guidance document for side-effect testing with plant protection products on non-target arthropods under semi-field and field conditions. The principles, methods, endpoints and interpretation of non-target arthropod semi-field and field trials which should be conducted for registration of plant protection products in the European Union are presented and discussed. The recommendations presented reflect the opinions of the experts from authority, academia, industry and consulting which participated at the IOBC (International Organisation of Biological Control), BART (Beneficial Arthropod Regulatory Testing) group and EPPO (European Plant Protection Organisation) Joint Initiative workshop held in Versailles (France) on the 25–26 October, 1999. 相似文献
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Septic tenosynovitis was diagnosed in seven cattle on the basis of history, physical examination, radiographs, cytological examination of tendon sheath fluids, and microbial culture. A commercially available indwelling multifenestrated silicone rubber drain was used to perform frequent lavage of the flexor tendon sheaths. The sepsis resolved in all cattle. Five of six cattle for which long-term (> 1 year) follow-up information was available were clinically sound on the affected limb and had remained productive members of the herd. 相似文献
76.
Euphytica - Foliar application of two spring wheat varieties, Anza and Yecora 70, with RH-531 several days before meiosis in a field experiment almost completely prevented seed development. A... 相似文献
77.
R.D. Vogt H.M. Seip H. Orefellen G. Skotte C. Irgens J. Tyszka 《Water, air, and soil pollution》2001,130(1-4):745-750
Soil water at an acid-sensitive forested catchment in southwestern Poland has been studied for four years. Median base saturation (BS) is only 5% in the podzol B-horizons. Very low pH values in the soil water from the O-horizons (10- and 90 percentiles pH 3.5 and 4.3) increased to a typical median pH in the B-horizons of 4.4, mainly by release of inorganic labile aluminium (Ali). Median concentrations in the B horizons were 3.4mg Ali L?1. Al-soil/soilwater interactions were studied over a large span of sulphate concentrations resulting from both a generally decreasing S-deposition during the last decades and an increase in precipitation during the study period. These changes led sulphate to leach from the mineral soil. Aluminium mobilisation is better described by jurbanite- than by gibbsite solubility. For the soils with aluminium saturation (AlS) >90%, there is a tendency that the concentration of Al3+ decreases less than divalent base cations with a decrease in SO4 2? concentration. This causes the critical load molar ratio (RCL={Al3+}/{Ca2++Mg2+}) to increase with a decrease in the sulphate concentration in soil water, which is not in agreement with a simple cation-exchange model. 相似文献
78.
A. B. S. Poléo E. Lydersen B. O. Rosseland F. Kroglund B. Salbu R. D. Vogt A. Kvellestad 《Water, air, and soil pollution》1994,75(3-4):339-351
The present study is mainly focusing on mortality variations of fish due to changing Alchemistry of mixing zones. An artificial mixing zone was made by pumping water from a limed stream and an acidic tributary into a mixing channel. Atlantic salmon (Salmo salar L.) parr were exposed to the mixed water, limed stream water, and acidic tributary water. Mortality, blood haematocrit and plasma Cl?-concentration were recorded. Neither mortality, nor changes in haematocrit and plasma Cl? were observed when fish were exposed to limed water, while in both acidic and mixed water, mortalities and loss of plasma Cl? were observed. The highest mortality rates were found within the initial part (0 to 20 s) of the mixing zone. Blood haematocrit increased only in fish exposed to acidic tributary water. Our results shows that changes in Al-chemistry and subsequent Al-polymerization occur when acidic tributary water is mixed with limed stream water. We have also demonstrated that the toxicity which can arise in mixing zones are greater than in the original acidic water before mixing. The variations in mortality observed are associated with the quality and quantity of Al-polymerization as well as ageing of the polymers. 相似文献
79.
João Barateiro Diogo Tiago Natal-da-Luz José Paulo Sousa Christian Vogt Carsten Nowak 《Journal of Soils and Sediments》2007,7(6):388-392
Background, Aims, and Scope The springtail Folsomia candida is a commonly used model species in ecotoxicological soil testing. The species reproduces parthenogenetically and, thus,
laboratories use different clonal lineages. In this study, we investigated if genetic divergence between F. candida strains impacts the reaction to chemical stress and may thus affect the outcome of toxicity tests.
Methods In two exposure assays (life-cycle reproduction test and avoidance behaviour test), three laboratory strains of F. candida from Portugal (PTG), Spain (SPN) and Denmark (DNK) were exposed to different concentrations of the reference chemical phenmedipham.
Genetic divergence among strains was estimated based on mitochondrial COI sequence data.
Results No significant differences between tolerance towards phenmedipham exposure were observed in a reproduction test. In contrast,
one strain (SPN) showed a decreased susceptibility to phenmedipham compared to the other strains (PTG and DNK) in the avoidance
assay.
Discussion A phylogenetic tree based on mitochondrial COI sequences revealed clear genetic differentiation between both ‘reaction types’.
Thus, we found a potential lineage dependent stress reaction in avoidance behaviour towards the pesticide.
Conclusions Our findings have implications for the comparability of test results among laboratories. Reproduction tests seem to be more
robust towards interclonal genetic differentiation than avoidance tests.
Recommendations and Perspectives We recommend the use of molecular tools for simple and cost effective genetic characterization of F. candida strains used in chemical avoidance tests. Closer investigations concerning the relation between genetic relatedness and chemical
response will provide a more detailed and comprehensive picture on the role of intraspecific genetic differentiation in stress
tolerance.
ESS-Submission Editor: Prof. Dr. Henner Hollert (henner.hollert@bio5.rwth-aachen.de) 相似文献
80.
In order to gain insight into the community structure and the biodegradative potential of bacteria residing in a BTEX-contaminated field site, with benzene as main pollutant, an investigation strategy with a variety of cultivation-independent and -dependent approaches was undertaken. Based on 16S ribosomal DNA sequence analysis, sampling stations in the center of the pollution plume were found to be dominated by a bacterial consortium affiliated with various members of the class of Proteobacteria and Firmicutes, including different sporulating and non-sporulating sulfate-reducing bacteria and members of the genus Geobacter. Non-polluted samples retrieved from outside the plume revealed several phylotypes which were also observed in the centre of the plume. Bacterial sequences retrieved from the fringe of the plume were dominated by several genera of beta Proteobacteria subclass which were not associated with other phylotypes obtained in this study. All sampling stations were tested positive for catechol 2,3-dioxygenase genes, indicating the presence of microorganisms with the genetic potential degrading aromatic compounds via the meta-cleavage pathway. The groundwater system at the down-gradient edge of the plume was characterized, in contrast to all other sampling stations in the center and outside the plume, by high numbers of cultivable bacteria and cultivable aerobic benzene and toluene degraders. These findings are also in accordance with the investigations based on fluorescent in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes, suggesting the presence of an actively benzene degrading bacterial community of beta Proteobacteria at the fringe of the pollution plume. 相似文献