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Pille F Martens A Schouls LM Peelman L Gasthuys F Schot CS De Baere C Desmet P Vandenberghe F 《Research in veterinary science》2004,77(3):189-195
Standard culturing techniques are often unrewarding in confirming diagnosis of synovial infection in the equine patient. Several human studies report the use of sensitive polymerase chain reaction (PCR) techniques for the detection of bacterial involvement in acute synovitis. However, successful extraction of bacterial DNA directly from clinical samples from horses without prior culture has not been reported yet. The goal of this study was to develop a sensitive and reliable method for molecular detection and identification of bacterial species in synovial fluid from horses with infectious synovitis. Synovial fluid samples from 6 horses with culture confirmed synovial infection were used for broad range 16S rRNA gene PCR. Synovial aspirates of 2 healthy horses were used as negative controls. Following extraction and purification of synovial fluid DNA, all samples were processed by touchdown PCR. Amplicons were detected by reverse line blot hybridisation and visualised with chemiluminescence. Pathogen-specific detection of 16S rRNA gene sequences was successful in all 6 synovial fluid samples. No bacterial DNA was detected in the aspirates from the negative control horses using touchdown PCR followed by 25 additional cycles of amplification. The identity of the pathogens was confirmed by DNA sequencing of the amplicons. It can be concluded that broad range 16S rRNA gene PCR followed by reverse line blot hybridisation is a promising technique for detection of bacterial DNA in synovial fluid samples. Further research should aim at the detection of bacterial DNA in synovial fluid samples suspected of infection but having negative culture results. When the 16S PCR proves to be reliable and more sensitive than standard culturing techniques, it may become a powerful tool in the diagnosis of synovial infection. 相似文献
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A GIS-based plant prediction model for wetland ecosystems 总被引：5，自引：0，他引：5
An existing non-spatial model for the prediction of response of wetland plant species on ecological factors has been transformed into a GIS-based prediction model which produces spatial output at the landscape scale. The input, spatial patterns of the ecological factors, were constructed with geostatistical spatial interpolation (kriging). With this GIS-based model the spatial patterns of presence and absence of 78 wetland plant species are predicted for an area with wetlands in the Netherlands of approximately 500 square kilometers. The GIS-based model has been validated, and the estimated uncertainty of the input has been propagated through the model. At the species level the output shows spatially coherent and non-random patterns. The validation is affected by the propagation of input errors through the model. The number of valid predictions declines approximately 10–20% when 95% confidence intervals are used in the validation. This study shows that it is feasible to use a geostatistical interpolation method to construct spatial patterns of ecological factors on a landscape scale and to use these patterns as input for a GIS-based prediction model. The added uncertainty on the input values however, affects the number of valid predictions of the model. 相似文献
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Linking habitat suitability and seed dispersal models in order to analyse the effectiveness of hydrological fen restoration strategies 总被引：1，自引：0，他引：1
A.H. van Loon H. Soomers P.P. Schot M.F.P. Bierkens J. Griffioen M.J. Wassen 《Biological conservation》2011,(3):1025-1035
The effectiveness of measures targeted at the restoration of populations of endangered species in anthropogenically dominated regions is often limited by a combination of insufficient restoration of habitat quality and dispersal failure. Therefore, the joint prediction of suitable habitat and seed dispersal in dependency of management actions is required for effective nature management. Here we demonstrate an approach, which links a habitat suitability and a seed dispersal model. The linked model describes potential species distribution as a function of current species distribution, species-specific dispersal traits, the number of successful dispersal events, dispersal infrastructure and habitat configuration. The last two variables were related to water management actions. We demonstrate the applicability of the model in a strategy analysis of hydrological restoration measures for a large fen area in which still numerous endangered plant species grow.With the aid of the linked model, we were able to optimise the spatial planning of restoration measures, taking into account both the constraints of water management practices on abiotic restoration and the effects of habitat fragmentation on dispersal. Moreover, we could demonstrate that stand-alone habitat suitability models, which assume unlimited dispersal, may considerably overestimate restoration prospects. For these reasons, we conclude that linked habitat suitability and dispersal models can provide useful insights into spatially differentiated potentials and constraints of nature restoration measures targeted at the sustainable conservation of endangered plant populations whose habitats have been deteriorated due to undesirable effects of land and water management on abiotic conditions. These insights may contribute to the design of cost-effective nature restoration and conservation measures. 相似文献
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N.M.?PieterseEmail author H. Olde?Venterink P.P.?Schot A.W.M.?Verkroost 《Landscape Ecology》2005,20(6):743-753
There is an ongoing debate as to whether nutrient contamination of groundwater under agricultural fields may cause nutrient-enrichment
and subsequent eutrophication in discharge areas. Often, there is only circumstantial evidence to support this supposition
(proximity of agricultural fields, direction of water flow, highly productive vegetation). Research on solute transport along
a flow path is necessary to evaluate the risk for eutrophication. In this paper we present results of such a study. Two transects
were established in a discharge meadow, a few meters downstream from fertilized cornfields. Highly productive vegetation in
parts of the meadow suggested nutrient-enrichment caused by inflow of contaminated groundwater. This supposition was supported
by an analysis of groundwater flow paths, residence times and chloride as tracer for pollution. However, the fate of nutrients
along the flow path indicated otherwise. While we found high concentrations of DIN (dissolved inorganic nitrogen), P and K
under the cornfields, DIN and P concentrations drop below detection limit when groundwater enters the meadow. Only K progressed
into the meadow but did not enter the root zone. We conclude that (1) polluted groundwater from the cornfields did not cause
the nutrient-enrichment, as indicated by the highly productive vegetation. Restoration projects in discharge areas should
not focus upon measures in upstream areas if only circumstantial evidence is available. Solute transport should be considered
as well. (2) Because K clearly showed to be the most mobile nutrient, its importance for nutrient-enrichment in discharge
wetlands merits more attention in future research. 相似文献
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van Oostrom H Doornenbal A Schot A Stienen PJ Hellebrekers LJ 《Veterinary journal (London, England : 1997)》2011,(3):338-344
The sedative and analgesic effects of continuous rate infusion (CRI) of dexmedetomidine (DEX) were investigated in Beagle dogs (n = 8) using auditory and somatosensory evoked potentials (AEPs and SEPs) recorded before, during and after a CRI of saline or DEX (1.0, 3.0, 5.0 μg/kg bolus, followed by 1.0, 3.0, 5.0 μg/kg/h CRI, respectively).The results showed a significant reduction in AEP at doses of 1.0 μg/kg/h and above and a significant reduction of the SEP at doses of 3.0 and 5.0 μg/kg/h. Neither the AEP nor the SEP was further reduced at 5.0 μg/kg/h when compared to 3.0 μg/kg/h, although a slower return towards baseline values was observed at 5.0 μg/kg/h. The mean plasma levels (±SEM) of DEX during infusion were 0.533 ± 0.053 ng/mL for the 1.0 μg/kg/h dose, 1.869 ± 0.063 ng/mL for the 3.0 μg/kg/h dose and 4.017 ± 0.385 for the 5.0 μg/kg/dose. It was concluded that in adult dogs, a CRI of DEX had a sedative and analgesic effect that could be described quantitatively using neurophysiological parameters. Sedation was achieved at lower plasma levels than required for analgesia, and DEX had a longer (but not larger) effect with infusion rates above 3.0 μg/kg/h. 相似文献
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Dependency of local mesotrophic fens on a regional groundwater flow system in a poldered river plain in the Netherlands 总被引：1，自引：0，他引：1
The effect of regional, subregional and local groundwater flow systems on mesotrophic fen ecosystems was studied in the polders of the Vecht River plain that borders the Pleistocene ice-pushed moraine of Het Gooi. Variation in the vegetation and in the habitat factors (groundwater and peat soil) of fens depends whether or not the fens are connected to the outflow of the regional groundwater system.Changes in the regional groundwater flow system, caused by changes in the water management of the polders, are probably responsible for the deterioration of mesotrophic fens. Drastic measures will have to be taken to restore the hydrology on a regional scale if the mesotrophic fens are to be saved from extinction.Hydrological research that integrates the results of regional and local studies is essential if the ecology of fen ecosystems is to be understood. 相似文献
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