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151.
Adrian C. Newton Christine A. Hackett David C. Guy 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(9):925-931
Powdery mildew populations were analysed to determine the effects of a resistance elicitor and cultivar mixtures on genetic complexity and diversity. Isolations were made from a range of spring barley monocultures and mixtures in a field trial, and characterised for virulence and RAPD profile. In a second trial, isolates were taken from a single mixture from untreated and resistance elicitor-treated areas and from the components of the mixture in monoculture. The mildew population was not only highly heterogeneous for virulence characteristics, but also proved heterogeneous within pathotypes for molecular markers, indicating the major impact of sexual recombination on population structure and the lack of clonal dominance. Various diversity measurements were compared and the value of dissimilarity measurement for revealing genetic distance within a population was highlighted. There was a trend towards increasing complexity as the season progressed, but there was no consistent relationship between cultivar or mixture, disease control treatment, fertiliser treatment, replicate or position in trial, and pathogen genotype. Whilst the resistance elicitor did reduce mildew by 78% in the first trial, and there was no interaction with fertiliser level in its expression, control was substantially less in the second trial. There were no differences between mildew isolates from elicitor and control treatments. It was felt that more effective and consistent resistance elicitors need to be developed before it can be stated that they are unlikely to be eroded by selecting resistant or adapted mildew genotypes. 相似文献
152.
David E Anderson Guy St Jean 《Veterinary Clinics of North America: Food Animal Practice》2008,24(2):319-34, vii
Surgery of the respiratory tract often is considered a last resort. However, these surgeries can be performed successfully, allowing for preservation of genetics and productivity. This article discusses surgery of the upper respiratory system. Aspects of physical, radiographic, endoscopic, and ultrasonographic examination are explored. Conditions of the nares, paranasal sinuses, nasopharynx, palate, nasolacrimal duct, pharynx, and larynx are covered. 相似文献
153.
The increased incidence and extended geographical reach of Dengue virus over the past two decades have made the development of an effective vaccine an international urgency. Various strategies are being pursued, including live, vectored and killed/recombinant preparations. For all approaches, the challenge is to induce a broad durable immune response against all four serotypes of Dengue virus simultaneously whilst avoiding the possible exacerbation of risk of developing the severe forms of disease through incomplete or modified responses. This review presents the current state of knowledge and discusses the challenges of further clinical development. 相似文献
154.
Elbers AR Backx A Meroc E Gerbier G Staubach C Hendrickx G van der Spek A Mintiens K 《Preventive veterinary medicine》2008,87(1-2):21-30
Starting August 2006, a major epidemic of bluetongue (BT) was identified in North-West Europe, affecting The Netherlands, Belgium, Germany, Luxemburg and the North of France. It was caused by BT virus serotype 8 (BTV-8), a serotype previously unknown to the European Union (EU). In this outbreak, the virus caused clinical disease in a few individual animals within cattle herds, whereas overt clinical disease was usually restricted to sheep. Investigations in Belgium suggested that the first clinical signs of BTV-8 appeared mid July 2006 in a cattle herd, while the first suspicion of a BT-outbreak in Belgium was reported on 17 August 2006. In the first 10 BTV-8 outbreaks in the Netherlands, the owners indicated that the first clinical signs started approximately 12-17 days before a suspicion was reported to the veterinary authorities via a veterinary practitioner. In BTV-8 affected sheep flocks, erosions of the oral mucosa, fever, salivation, facial and mandibular oedema, apathy and tiredness, mortality, oedema of the lips, lameness, and dysphagia were among the most frequent clinical signs recorded. The most prominent clinical signs in BTV-8 affected cattle herds were: crusts/lesions of the nasal mucosa, erosions of lips/crusts in or around the nostrils, erosions of the oral mucosa, salivation, fever, conjunctivitis, coronitis, muscle necrosis, and stiffness of the limbs. Crusts/lesions of nasal mucosa, conjunctivitis, hyperaemic/purple coloration and lesions of the teats, and redness/hypersensitivity of the skin were relatively more seen on outbreak farms with cattle compared to sheep. Mortality, oedema of the head and ears, coronitis, redness of the oral mucosa, erosions/ulceration of tongue mucosa, purple coloration of the tongue and tongue protrusion and dyspneu were relatively more seen on outbreak farms with sheep compared to cattle. 相似文献
155.
Elbers AR Backx A Mintiens K Gerbier G Staubach C Hendrickx G van der Spek A 《Preventive veterinary medicine》2008,87(1-2):31-40
Data collected in the Netherlands during the Bluetongue serotype 8 (BTV-8) epidemic indicated that in outbreak cattle herds, predominantly dairy and nursing cows were clinically affected and not young stock, beef cattle, beef calves, or breeding animals. In outbreak sheep flocks, mainly ewes and - if present - rams, were clinically affected and not the lambs. Median morbidity rate in outbreak herds was 1.85 per 100 sheep-month at risk and 0.32 per 100 cattle-month at risk for sheep and cattle, respectively. The mean proportion of BT-affected animals in outbreak herds that recovered from clinical disease was approximately eight times higher for cattle compared to sheep in the Netherlands. Median mortality rate in outbreak herds was 0.5 per 100 sheep-month at risk of dying and 0 per 100 cattle-month at risk of dying for sheep and cattle, respectively. Median recovery time of both sheep and cattle that recovered from clinical disease in outbreak herds was 14 days. Median case fatality was 50% in sheep outbreak flocks and 0% in outbreak cattle herds. It is concluded that morbidity and mortality in outbreak cattle herds was very limited during the BTV-8 epidemic in the Netherlands in 2006. In outbreak sheep flocks, morbidity was limited, with exceptions for a few flocks. However, almost 50% of the clinically sick sheep died in outbreak sheep herds. 相似文献
156.
Mark D.G. Pinches Guy Liebenberg Mark F Stidworthy 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2008,37(4):443-446
Abstract: A 7‐year‐old neutered male polecat‐type ferret (Mustela putorius furo) was presented for evaluation of a cutaneous mass close to the preputial orifice. Cytologic examination of a fine‐needle aspirate revealed numerous large clumps of amorphous pink mucinous material and numerous large clumps of slightly pleomorphic epithelial cells. The cells were arranged in papillary structures, palisades, and loosely cohesive sheets with a vaguely honeycomb appearance. Occasional acinar formations were also seen. The cells had moderate to large amounts of finely granular gray to gray–blue cytoplasm. The cells were round to wispy and elongated, with indistinct borders. Often, anuclear cytoplasmic clumps were seen free in the background or adjacent to intact cells. Nuclei were round to oval and usually off‐center. Chromatin was finely stippled and contained 1–3 indistinct nucleoli. Anisokaryosis and anisocytosis were moderate. Binucleated cells were noted occasionally. The cytologic features were consistent with a carcinoma of probable apocrine origin. Histopathologic examination supported a diagnosis of secretory apocrine adenocarcinoma of the preputial skin. Secretory apocrine adenocarcinomas of the prepuce are seen relatively frequently in ferrets, although their cytologic appearance has not been described widely. These neoplasms carry a poor prognosis although prompt surgical removal with wide and deep surgical margins and adjunctive radiotherapy may improve survival. 相似文献
157.
Yoshiaki Nakagawa Guy Smagghe Soichi Kugimiya Kazunari Hattori Tamio Ueno Luc Tirry Toshio Fujita 《Pest management science》1999,55(9):909-918
Insecticidal activity against the Colorado potato beetle, Leptinotarsa decemlineata, was measured for a series of substituted N-tert-butyl-dibenzoylhydrazines, in which one of the benzoyl moieties closer to the tert-butyl group was fixed as being 2-chloro-substitued and the other variously substituted singly or doubly. The effects of substituents on the activity were quantitatively analysed using the classical quantitative structure–activity relationship (QSAR) procedure. The activity against the Colorado potato beetle increases with the molecular hydrophobicity. In addition, various types of steric effect are at work, depending upon the positions. Hydrogen-bonding acceptor substituents at the para position enhance the activity. There seem to be threshold (or optimum) values, albeit position-dependent, in the molecular hydrophobicity, above which the activity starts to decrease. This biphasic contribution of the molecular hydrophobicity to activity against coleopterous larvae is the most conspicuous difference in substituent effects from those found for similar compounds against lepidopterous pest insects, and may be the basis of the variations in the activity spectrum for certain compounds in this series. The introduction of bulkier substituents into the meta- and para-positions of the benzene ring, apart from the tert-butyl group, is unfavorable to activity. LD50 values against Colorado potato beetle larvae of methoxyfenozide (RH-2485) and tebufenozide (RH-5992) were in the order of 10−7 mol per insect, whereas those of RH-5849, and halofenozide (RH-0345) were very low, 10−9–10−10 mol per insect being selective to the coleopterous larvae. © 1999 Society of Chemical Industry 相似文献
158.
159.
Kamangar Saman Bahrami Taning Clauvis Nji Tizi De Jonghe Kris Smagghe Guy 《植物病害和植物保护杂志》2019,126(6):529-534
Journal of Plant Diseases and Protection - Potato virus Y (PVY) is a destructive plant virus causing important damage in different crops, particularly in potato. PVY is transmitted in a... 相似文献
160.
Landscape Ecology - Studying biodiversity in light of increased fragmentation in agroecosystems requires the understanding of scale-dependent and multi-scale determinants of various community... 相似文献