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Detection of traces of tetracyclines from fish with a bioluminescent sensor strain incorporating bacterial luciferase reporter genes 总被引:3,自引:0,他引:3
Pellinen T Bylund G Virta M Niemi A Karp M 《Journal of agricultural and food chemistry》2002,50(17):4812-4815
Bioluminescent Escherichia coli K-12 strain for the specific detection of the tetracycline family of antimicrobial agents was optimized to work with fish samples. The biosensing strain contains a plasmid incorporating the bacterial luciferase operon of Photorhabdus luminescens under the control of the tetracycline responsive element from transposon Tn10 (Korpela et al. Anal. Chem. 1998, 70, 4457-4462). The extraction procedure of oxytetracycline from rainbow trout (Oncorhynchus mykiss) tissue was optimized. There was neither need for centrifugation of homogenized tissue nor use of organic solvents. The lowest levels of detection of tetracycline and oxytetracycline from spiked fish tissue were 20 and 50 microg/kg, respectively, in a 2-h assay. The optimized assay protocol was tested with fish that were given a single oral dose of high and low concentrations of oxytetracycline. The assay was able to detect oxytetracycline residues below the European Union maximum residue limits, and the results correlated well with those obtained by conventional HPLC (R = 0.81). 相似文献
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Kurittu J Lönnberg S Virta M Karp M 《Journal of agricultural and food chemistry》2000,48(8):3372-3377
The potentiality of using a luminescent Escherichia coli strain for the specific detection of tetracycline residues in raw bovine milk was investigated. The sensor cells contain a reporter plasmid carrying the bacterial luciferase operon of Photorhabdus luminescens under the control of the tetracycline responsive control region from transposon Tn10. Incubation of the cells with the sample containing tetracyclines increases the light emission of the sensor cells. The most sensitive tetracycline detection was achieved in 120 min and by using CDTA as a chelating agent in the assay. Heat-treatment of milk before the assay decreased the variations in background luminescence signals and in tetracycline-induced luminescence between different milk samples. The detection limits for tetracycline, oxytetracycline, chlortetracycline, doxycycline, methacycline, demeclocycline, and minocycline were between 2 and 35 ng/mL. Nontetracycline antibiotics did not significantly interfere with the detection of tetracyclines. 相似文献
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Pöykiö Risto Taskila Eero Perämäki Paavo Nurmesniemi Hannu Kivilinna Veli-Antti Kuokkanen Toivo Virta Pirkko 《Water, air, and soil pollution》2004,158(1):325-343
This paper compares the long-term data of EOX (Extractable Organic Halogens) determinations in sediments, trichloroguaiacol, i.e. 3,4,5-trichloroguaiacol and 4,5,6-trichloroguaiacol, determinations in the bile of perch (Perca fluviatilis L.) and changes in bottom fauna communities (Pontoporeia affinis L., Mesidotea entomon L., Valvata spp. L.) during 1994–2003. The study area is located at Kemi, on the Gulf of Bothnia, Northern Finland, and is affected by effluent discharged from the pulp and paper mills of Stora Enso Oyj and Oy Metsä-Botnia Ab. The Kemi municipal sewage plant, and River Kemijoki also impose a load in the same area. The main purpose of the study was to assess whether the state of the exposed water ecosystem has improved on the basis of the concentrations of organochlorine compounds in sediment and in perch, due to the modernisation of the wastewater treatment at the mills. In addition, we also investigated whether the changes in the bottom fauna community indicate an improvement in the purification of the effluents. The results indicate that the concentrations of trichloroguaiacols (–1) in perch reflect the decreased discharges of chlorinated substances from the mills. The EOX concentrations in bottom sediments have also decreased to below 50 of Cl g–1 in most parts of the study area, which is in good agreement with the reduction in the discharge of organochlorines. According to the long-term changes in bottom fauna, the reduction in the discharge of organochlorine compounds due to modernisation of the pulp mills is reflected in a recovery of the benthic fauna, especially Valvata spp. L. and Pontoporeia affinis L. 相似文献
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Bäckman L Nyberg L Soveri A Johansson J Andersson M Dahlin E Neely AS Virta J Laine M Rinne JO 《Science (New York, N.Y.)》2011,333(6043):718
Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory. 相似文献
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The aim of the study was to examine how the thickness and species of softwood influence cupping during cyclic conditions.
The study was conducted with full-scale test walls in laboratory conditions. On the basis of the results, the thickness and
species of softwood both have a significant influence on cupping of the cladding board. The boards made of Norway spruce were
considerably more resistant to cupping than those made of Scots pine sapwood. Boards made of Scots pine sapwood were more
likely to remain curved after each drying period. It appears probable that the cupping sensitivity of Scots pine sapwood affects
the durability of the cladding, e.g., causing cracking formation on the surface and peeling of the coating. From the curving
results, it is possible to estimate surface elongation and durability of the wood surface and of the coating in cyclic conditions. 相似文献
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