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排序方式: 共有640条查询结果,搜索用时 15 毫秒
1.
A W vd Giessen R Peters P A Berkers W H Jansen S H Notermans 《The Veterinary quarterly》1991,13(1):41-46
The contamination of poultry in the Netherlands with Salmonella enteritidis was tested. For this, different methods (detection of S. enteritidis in faecal samples of 25 g; detection of S. enteritidis in cloacal swabs; detection of S. enteritidis by serological testing of antibodies in serum) were compared for their efficiency to detect S. enteritidis in flocks of poultry. Testing of faecal samples clearly yielded the best results. This method was used in a transmission study, in which 14 flocks descending from a contaminated primary mother flock were screened for the presence of S. enteritidis. The method was also used for screening 49 flocks of laying hens and 52 flocks of broiler chickens throughout the Netherlands. From the transmission study it became clear that S. enteritidis, phage type 2 (Dutch phage set) was isolated both from the mother flock and from five of the descendent flocks. Screening of poultry flocks for the presence of salmonella revealed that salmonella was present in 47% of the layer flocks and in 94% of the broiler flocks. S. enteritidis was isolated from 15% of the flocks screened. 相似文献
2.
P. H. M. Roseboom D. Peters 《European journal of plant pathology / European Foundation for Plant Pathology》1984,90(4):133-141
Beet yellows virus can be detected in leaf extracts of infected sugarbeet plants by ELISA. The use of discs was studied and proved to be a valuable and qualitatively reliable method. Leaf material could be stored at 4o or 22°C for at least six days without affecting the detection of this virus by ELISA. A dramatic decrease in ELISA values was found when leaf extracts were frozen.In an analysis of the distribution of virus over the plant it was found that young leaves present at the moment of infection and those which had still to develop after infection will contain virus. Symptoms produced by systemic virus invasion occur on the oldest leaves containing virus.Samenvatting Het bietevergelingsvirus kan op betrouwbare wijze met de ELISA methode in geïnfecteerde bieteplanten worden aangetoond. Een aanzienlijke vereenvoudiging van de procedure kan worden bereikt met de zogenaamde disc-method, waarbij intacte ponsstukjes in de putjes van de ELISA-plaat worden geïncubeerd. Hierbij komt voldoende virus uit de ponsstukjes voor ELISA vrij. Bladmateriaal kon op verschillende wijzen bewaard worden zonder dat de mogelijkheid om het virus aan te tonen achteruitging. Met bladextracten die ingevroren waren, werden echter slechte resultaten verkregen.In een analyse naar de verdeling van het virus over het loof bleek het virus voor te komen in de geïnoculeerde bladeren, in die bladeren die op het tijdstip van inoculatie minder dan de helft van hun uiteindelijke lengte bereikt hadden en in de bladeren die nog moesten verschijnen. De symptomen ontwikkelden zich op de oudste systemisch geïnfecteerde bladeren. 相似文献
3.
The minimal infectious dose of the H52 strain of infectious bronchitis virus for organ cultures of oviduct and kidney was compared in chickens of different ages. Organ cultures of oviduct were found to be highly susceptible to infection regardless of the age of chicken and no difference in susceptibility could be demonstrated between cultures of the magnum and uterus regions of the mature oviduct. Kidney organ cultures were less susceptible and resistance to infection increased significantly (P less than 0.001) with the age of the chicken from which cultures were prepared. 相似文献
4.
K Deichsel H-O Hoppen RM Bruckmaier G Kolm C Aurich 《Reproduction in domestic animals》2005,40(2):117-122
Lactation in the mare is associated with changes in the release of metabolic as well as reproductive hormones. Plasma glucose concentration is constantly reduced in lactating compared with non-lactating mares. Several metabolic signals have been proposed to link nutrition and somatic metabolism with reproductive function. The following experiment was performed to study the effect of acute hypoglycaemia on the release of insulin-like growth factor-1 (IGF-1) and luteinizing hormone (LH) in cyclic mares. Different doses of insulin (0.1 and 0.2 IU/kg body weight) were given to induce a decrease in plasma glucose concentration, as existent in lactating mares. All horses treated with insulin developed a hypoglycaemia over a time period of nearly 10 h. The IGF-1 and LH were analysed before and after insulin administration. At no point of time, a significant difference between the two insulin treatments and the control treatment was observed. Therefore, the hypoglycaemic horse is apparently able to provide the brain with sufficient glucose. Short-term hypoglycaemia does not affect the hypothalamo-pituitary-ovarian axis, and concentrations of IGF-1 and LH remained stable during insulin-induced hypoglycaemia. An acute change in plasma glucose concentration is thus not or at least not the only metabolic signal that links nutrition and somatic metabolism with reproductive function in the horse mare. 相似文献
5.
A study was carried out to demonstrate that Rice yellow mottle virus (RYMV), a virus known to be transmitted by beetles, can spread between rice plants by direct leaf contact caused by wind. Almost all healthy plants surrounding an infected plant became infected when exposed to a fan blowing for 15 min at a distance of 50 cm. Spread of RYMV by plant contact, mediated by wind, was also demonstrated in field experiments, the extent of spread depending on plant density. Infection was almost 10 times higher in plots with a density of 33 plants m−2 than in plots with 16 plants m−2 . Less spread was observed in plots protected by 1·5 m high windscreens. It is suggested that wind-mediated spread of RYMV may result from abrasive contact between leaves of plants. 相似文献
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Evaluation of Serum Aspergillus‐Specific Immunoglobulin A by Indirect ELISA for Diagnosis of Feline Upper Respiratory Tract Aspergillosis
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10.
Louis R. Iverson Frank R. ThompsonIII Stephen Matthews Matthew Peters Anantha Prasad William D. Dijak Jacob Fraser Wen J. Wang Brice Hanberry Hong He Maria Janowiak Patricia Butler Leslie Brandt Christopher Swanston 《Landscape Ecology》2017,32(7):1327-1346