PCR-based determination of colonization patterns during potato tuber infection by single and multiple pathogens     

A. El Hadrami  O. Wally  L. R. Adam  F. Daayf 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(3):201-218

Potato tubers piled in storage are prone to infection by numerous pathogens. Each pathogen can cause damage alone, but severe losses often arise when more than one pathogen is involved. Currently, only a visual diagnosis is practiced on potato tubers before storing them, which does not allow any prediction of further disease spread. The aim of the present study was to determine differences in patterns of tissue colonization by several tuber decay pathogens and how late blight infection affects further tuber colonization by other important tuber pathogens. This study was conducted using artificial inoculation of potato tubers and PCR to provide an early and accurate diagnosis of disease development for major potato tuber rots, and to assess potential synergism/antagonism between Phytophthora infestans and other pathogens in stored tubers. In order to accurately follow the progress of each pathogen in tuber tissues, samples were collected over time from both the surface (peel, 0–2 mm depth) and internal tissues (flesh, depth > 2 mm) of the tubers at various distances from the inoculation site, at 3, 5, 7, 10, 12, 14, 17, and 19 days after inoculation. Successful detection of single or multiple pathogens was achieved using specific PCR-primers for each pathogen. Pathogens were always detected several centimeters ahead of the visible lesions. This tracking enabled us to determine the extent of colonization both on the tuber’s surface and in internal tissues by each tested pathogen, either after single or multiple infections involving P. infestans as the primary pathogen. The presence of P. infestans was shown to enhance the development of Pectobacterium atrosepticum and to slow down that of P. erythrospetica and Pythium ultimum. No noticeable effect on further tuber colonization by F. sambucinum, V. dahliae or V. albo-atrum was observed in the presence of P. infestans. This approach involving more than one pathogen is more realistic than classical studies considering single pathogens, and may be helpful in monitoring the sanitary status of stored tubers. Our results make the outcome of certain combinations of pathogens in potato tubers more predictable and may result in more efficient preventive measures.  相似文献   

Epidural anaesthesia in donkeys.     

M Shoukry  M Saleh  K Fouad 《The Veterinary record》1975,97(23):450-452

Epidural anaesthesia was tested on 40 donkeys. The second intercoccygeal space was found suitable for satisfactory induction and a dose of 8 to 10 ml of 1 per cent procaine hydrochloride was recommended for inducing posterior epidural anaesthesia and 30 ml of 2 per cent for anterior epidural anaesthesia.  相似文献   

Application of micromechanical models to tensile properties of wood–plastic composites     

Sébastien Migneault  Ahmed Koubaa  Fouad Erchiqui  Abdelkader Chaala  Karl Englund  Michael P. Wolcott 《Wood Science and Technology》2011,45(3):521-532

Wood–plastic composites (WPC) were produced with white birch pulp fibers of different aspect ratios (length-to-diameter), high-density polyethylene, and using two common processes: extrusion or injection molding. Three additive levels were also used: no additive, compatibility agent, and process lubricant. Fiber size was measured with an optical fiber quality analyzer. Tensile properties of WPC were measured and modeled as a function of fiber aspect ratio. Models were fitted to experimental values using the minimum sum of squared error method. A shift from the oriented fiber case (injection molding) to the randomly oriented fiber case (extrusion) was achieved using a fiber orientation factor. Fiber/matrix stress transfer increased with increasing fiber aspect ratio. Stress transfer was reduced with the use of process lubricant. Unexpectedly, the compatibility agent had the same effect. Fiber strength and stiffness contributions to the composite were lower than those of intrinsic fiber properties.  相似文献   

Expression of p53 during apoptosis induced by D-galactosamine and the protective role of PGE1 in cultured rat hepatocytes     

Fouad D  Ataya FS  Muntane J 《Pakistan journal of biological sciences: PJBS》2011,14(21):976-983

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US-8 and US-11 genotypes ofPhytophthora infestans from potato and tomato respond differently to commercial fungicides     

Fouad Daayf  Harold W. Platt 《American Journal of Potato Research》2003,80(5):329-334

Isolates ofPhytophthora infestans collected in Canada in 1997 from both potatoes and tomatoes, were tested on potato leaf discs for their response to an equal active ingredient concentration (10 μg a.i./mL) of the following commercial fungicides: Acrobat MZ (Dimethomorph and Mancozeb), Ridomil Gold (metalaxyl-m), Dithane (Mancozeb), Curzate (Cymoxanil), Bravo (Chlorothalonil), and Tattoo C (Propamocarb and Chlorothalonil). Relative percent leaf infection values, estimated on fungicide-treated vs fungicide-free leaf discs, were compared among isolates from the US-8 and US-11 genotypes isolated from the two host plants. Based on an equal concentration of each fungicide’s active ingredients, variations in relative percent leaf infection were recorded between US-8 and US-11 genotypes, and between potato and tomato isolates within each genotype. Bravo and Tattoo C used with similar active ingredients concentrations were the most inhibitory to all groups of isolates. Dithane and Ridomil Gold provided uniform low inhibition againstP. infestans when tested on potato leaf discs. The different behavior ofP. infestans isolates from potato vs tomato suggests that management of late blight in these two important crops must take such differences into consideration. In particular, the nature and concentration of the fungicides to be applied must take into account any information available about genotypes present on each crop.  相似文献   

Impact of Organic Amendments on Groundwater Nitrogen Concentrations for Sandy and Calcareous Soils     

Fouad H. Jaber  Sanjay Shukla  Peter J. Stoffella  Thomas A. Obreza  Edward A. Hanlon 《Compost science & utilization》2013,21(3):194-202

Experiments were conducted on calcareous and sandy soils to investigate the effects of organic amendments for vegetable production on groundwater nitrogen (N) concentration in south Florida. The treatments consisted of applying yard and food residuals compost, biosolids compost, a cocompost of the municipal solid waste and biosolids, and inorganic fertilizer. Nitrate nitrogen (NO₃-N), ammonium nitrogen (NH₄-N), and total N concentrations were collected for a period of two years for both soils. Statistical analysis results revealed that for the three species tested, there were no significant differences among treatments. NO₃-N concentrations for all treatments remained less than the maximum contamination level (10 mg/L). NO₃-N transport to groundwater was higher in calcareous soil (mean=5.3 mg/L) than in sandy soil (mean=0.6 mg/L). NH₄-N concentrations ranged from 0 to 13.6 mg/L throughout the experiment. Calcareous soil had lower NH₄-N concentrations (mean=0.1 mg/L) than sandy soils (mean=0.7 mg/L). Total N ranged from 0.4 to 21.7 mg/L for all treatments for both soils reflecting high adsorption of dissolved organic N in both soils. Overall, results indicated that all the compost treatments were comparable to inorganic fertilizer with regard to N leaching and N concentrations in the groundwater while producing similar or higher yields.  相似文献   

Farmers' knowledge,perceptions, and farm-level management practices of citrus pests and diseases in Morocco     

Lahlali  Rachid  Jaouad  Manal  Moinina  Alieu  Mokrini  Fouad  Belabess  Zineb 《植物病害和植物保护杂志》2021,128(5):1213-1226

Journal of Plant Diseases and Protection - This paper documents pest management practices adopted by citrus farmers in two of the citrus-growing regions in Morocco. The survey data propose possible...  相似文献   

Egg production, egg quality and crop content of Rhode Island Red hens grazing on natural tropical vegetation     

Khaled Abouelezz Fouad Mohammed  Luis Sarmiento-Franco  Ronald Santos-Ricalde  Javier Francisco Solorio-Sanchez 《Tropical animal health and production》2013,45(2):367-372

The aim of this experiment was to study the suitability of the outdoor system for Rhode Island Red hens under the tropical conditions of southern Mexico. Twelve floor pens, each containing four birds, were divided randomly into two groups. The first group was raised indoors only, while each of the second group replicates had access to an outdoor area with natural-grown vegetation from 0800 to 1700 hours daily. Both groups fed ad libitum on a commercial layers diet. The results revealed no differences in body weight between treatments. The outdoor group recorded significantly higher egg laying rate (86.90 vs. 78.05 %), higher egg mass (50.66 vs. 45.30 g egg/hen/day), and higher feed intake (103.70 vs. 97.67 g/day) versus the indoor group. The outdoor group had eggs with darker yellow yolks (9.46 vs. 5.46), lower yolk, and higher albumen proportions (P?<?0.05) versus the indoor group. The crop content of the outdoor hens consisted of 86.55 % concentrated feed, 6.30 % plant material, 2.27 % grit stones, 1.69 % snails and oyster shells, 1.25 % seeds, 0.95 % farm wastes, and 0.99 % insects, worms, and larvae. Of the outdoor hens, 43.1 % was observed to be in the range at each scanning time. The outdoor system in the tropics had beneficial effects on Rhode Island Red hen performance, and the hens utilized the outdoor area effectively and obtained various feed items.  相似文献   

Differential activation and suppression of potato defence responses by Phytophthora infestans isolates representing US‐1 and US‐8 genotypes     

X. Wang  A. El Hadrami  L. R. Adam  F. Daayf 《Plant pathology》2008,57(6):1026-1037

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The role of crop-pollinator relationships in breeding for pollinator-friendly legumes: from a breeding perspective     

Reid G. Palmer  Paola T. Perez  Evelyn Ortiz-Perez  Fouad Maalouf  María José Suso 《Euphytica》2009,170(1-2):35-52

Breeders are encouraged to develop breeding approaches that strive to integrate food production into the healthy functioning of agro-ecosystems. In the case of legumes, this approach should preserve bee fauna by providing suitable floral resources within the crops themselves. In parallel, legume breeding for sustainable agriculture is linked to the development of environmental services. Foraging places and nesting sites for solitary and social bees are some of the ecological services provided for legumes. Crops with floral attractiveness and rewards for insects can be used to enhance pollinator conservation as well as crop yield and yield stability. We analyze how understanding crop-pollinator relationships (CPR) can contribute to the production of high-yielding and pollinator-friendly varieties by examining: (1) The status of knowledge on mating systems and floral traits; (2) The contribution of CPR understanding to plant breeding for both hybrid-seed production and open-pollinated population improvement.  相似文献