Development of resistance and cross-resistance in fenvalerate and deltamethrin selected strains of Spodoptera littoralis (Boisd.)     

Medhat R. Riskallah  Samir F. Abd-Elghafar  Mohamed R. Abo-Elghar  Moustafa E. Nassar 《Pest management science》1983,14(5):508-512

Resistances of 33- and 27-fold to the pyrethroids fenvalerate and deltamethrin, respectively, have been induced in larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd.) by selection of two subcolonies of a field population in the laboratory. Selected strains showed relatively high levels of resistance (11- to 36-fold) to all the tested pyrethroids, moderate levels of cross-resistance (3- to 13-fold) to DDT and the carbamate aminocarb, and a slight increase in tolerance levels to endrin and lindane. The pyrethroid-resistant strains, by contrast, manifested no cross-resistance to the organophosphorus compounds that were tested. Moreover, a negative crossresistance was observed in the pyrethroid-resistant strains to dicrotophos, methamidophos and the carbamate methomyl.  相似文献   

Biological control of Sclerotinia minor using a chitinolytic bacterium and actinomycetes   总被引：4，自引：0，他引：4  

K. A. El-Tarabily †  M. H. Soliman ‡  A. H. Nassar †  H. A. Al-Hassani  K. Sivasithamparam  F. McKenna  G. E. ST. J. Hardy 《Plant pathology》2000,49(5):573-583

Isolates of 85 bacteria and 94 streptomycete and 35 nonstreptomycete actinomycetes were obtained from a lettuce-growing field in Al-Ain, United Arab Emirates, on colloidal chitin agar, and screened for their ability to produce chitinase. Twenty-three bacteria and 38 streptomycete and 15 nonstreptomycete actinomycete isolates produced high levels of chitinase and were examined in vitro for their ability to suppress the growth of Sclerotinia minor , a pathogen causing basal drop disease of lettuce. The three most suppressive isolates were examined further for their production of β-1,3-glucanase and antifungal activity as well as their ability to colonize the roots and rhizosphere of lettuce in vitro and in planta . The three isolates, Serratia marcescens, Streptomyces viridodiasticus and Micromonospora carbonacea , significantly reduced the growth of S. minor in vitro , and produced high levels of chitinase and β-1,3-glucanase. Streptomyces viridodiasticus also produced antifungal metabolite(s) that significantly reduced the growth of the pathogen in vitro . When the pathogen was presented as the sole carbon source, all three isolates caused extensive hyphal plasmolysis and cell wall lysis. Serratia marcescens and St. viridodiasticus were competent to varying degrees in colonizing the roots of lettuce seedlings after 8 days on agar plates and the rhizosphere within 14 days in pots, with their competency being superior to that of M. carbonacea . All three isolates, individually or in combination, were antagonistic to S. minor and significantly reduced incidence of disease under controlled glasshouse conditions.  相似文献   

Comparison of innate immune agonists for induction of tracheal antimicrobial peptide gene expression in tracheal epithelial cells of cattle     

Lesley Berghuis  Khaled Taha Abdelaziz  Jodi Bierworth  Leanna Wyer  Gabriella Jacob  Niel A Karrow  Shayan Sharif  Mary Ellen Clark  Jeff L Caswell 《Veterinary research》2014,45(1)

Bovine respiratory disease is a complex of bacterial and viral infections of economic and welfare importance to the beef industry. Although tracheal antimicrobial peptide (TAP) has microbicidal activity against bacterial pathogens causing bovine respiratory disease, risk factors for bovine respiratory disease including BVDV and stress (glucocorticoids) have been shown to inhibit the induced expression of this gene. Lipopolysaccharide is known to stimulate TAP gene expression, but the maximum effect is only observed after 16 h of stimulation. The present study investigated other agonists of TAP gene expression in primary cultures of bovine tracheal epithelial cells. PCR analysis of unstimulated tracheal epithelial cells, tracheal tissue and lung tissue each showed mRNA expression for Toll-like receptors (TLRs) 1–10. Quantitative RT-PCR analysis showed that Pam3CSK4 (an agonist of TLR1/2) and interleukin (IL)-17A significantly induced TAP gene expression in tracheal epithelial cells after only 4–8 h of stimulation. Flagellin (a TLR5 agonist), lipopolysaccharide and interferon-α also had stimulatory effects, but little or no response was found with class B CpG ODN 2007 (TLR9 agonist) or lipoteichoic acid (TLR2 agonist). The use of combined agonists had little or no enhancing effect above that of single agonists. Thus, Pam3CSK4, IL-17A and lipopolysaccharide rapidly and significantly induce TAP gene expression, suggesting that these stimulatory pathways may be of value for enhancing innate immunity in feedlot cattle at times of susceptibility to disease.  相似文献   

Squamous Cell Carcinoma in a Capybara (Hydrochoerus hydrochaeris)     

Takahisa HAMANO  Fumio TERASAWA  Yoshiharu TACHIKAWA  Atsuko MURAI  Takashi MORI  Khaled EL-DAKHLY  Hiroki SAKAI  Tokuma YANAI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(9):1301-1304

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Evaluation of proposed mesqa improvements     

Herman Depeweg  Khaled Hussein Bekheit 《Irrigation and Drainage Systems》1997,11(4):299-322

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Suspended-sediment transport in an intensively cultivated watershed in southeastern California   总被引：1，自引：0，他引：1  

Peng Gao  Gregory B. Pasternack  Khaled M. Bali  Wesley W. Wallender 《CATENA》2007,69(3):1289

The purpose of this study is to investigate the variation of sediment movement at multiple spatial and two temporal scales of an agricultural watershed in southeastern California where surface runoff is primarily supplied by irrigation. An extensive turbidity and stage monitoring program based on grab sampling using 500-mL plastic bottles and in situ monitoring using both turbidity sensors and pressure transducers was designed to capture the spatial and temporal heterogeneities of suspended-sediment loads. The obtained turbidity values and stages at weekly and 5-min time scales were subsequently converted to suspended-sediment concentrations and water discharges, respectively, using established calibration methods. Weekly data were analyzed using a mass-balance approach to distinguish erosion and deposition processes in drain channels at various spatial scales. Further analysis on weekly data led to an empirical model describing the process of sediment transport at various spatial scales. The model revealed that drain channels at larger spatial scales (i.e. downstream channels) tended to be dominated by weekly net deposition, while those at smaller spatial scales (i.e. upstream channels) were controlled by weekly net erosion. However, analysis of the 5-min data showed that in small-scale drain channels, large amount of sediment was indeed deposited over a short period of one week (about one day). In the rest of the week, low-intensity erosion prevailed. Therefore, sediment transport in the study watershed was generally controlled by deposition, which supports the necessity of on-going drain-channel dredging by Imperial Irrigation District.  相似文献   

Cassava Genetic Resources: Extinct Everywhere in Brazil     

Nagib M. A. Nassar 《Genetic Resources and Crop Evolution》2006,53(5):975-983

Wild cassava, Manihot spp. are sources of many useful characters. Their occurrence in natural habitats is diminishing day after day and a number of them almost have come to extinction. It is suggested that in situ conservation should be followed. It is appealed to concerned authorities to make an effort for their salvation.  相似文献   

Theileria infection in camels (Camelus dromedarius) in Egypt.     

A M Nassar 《Veterinary parasitology》1992,43(1-2):147-149

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Effects of nymphal density (Bactericera trigonica) and feeding on photosynthetic pigments,proline content and phenolic compounds in carrot plants     

Othmen  Soukaina Ben  Boussaa  Faten  Hajji-Hedfi  Lobna  Abbess  Khaled  Dbara  Soumaya  Chermiti  Brahim 《European journal of plant pathology / European Foundation for Plant Pathology》2022,163(1):51-59

European Journal of Plant Pathology - Insect feeding induces physiological and biochemical changes in host plants. Indeed, symptom severity often depends on insect density. Recently, the carrot...  相似文献   

Greenhouse gas emissions and nutrient supply rates in soil amended with biofuel production by-products     

Khaled D. Alotaibi  Jeff J. Schoenau 《Biology and Fertility of Soils》2013,49(2):129-141

Ethanol production results in distiller grain, and biodiesel produces glycerol as by-product. However, there is limited information on effects of their addition on evolution of N₂O and CO₂ from soils, yet it is important to enable our understanding of impacts of biofuel production on greenhouse gas budgets. The objective of this study was to evaluate the direct effects of adding wet distillers grain (WDG), thin stillage (TS), and glycerol at three rates on greenhouse gas emissions (N₂O and CO₂) and nutrient supply rates in a cultivated soil from the Canadian prairies. The WDG and TS application rates were: 100, 200, or 400 kg N ha^?1, whereas glycerol was applied at: 40, 400, or 4,000 kg C ha^?1 applied alone (G???N) or in a combination with 300 kg N ha^?1 (G?+?N). In addition, conventional amendments of urea (UR) and dehydrated alfalfa (DA) were added at the same rates of total N as the by-products for comparative purposes. The production of N₂O and CO₂ was measured over an incubation period of 10 days in incubation chambers and Plant Root Simulator? resin membrane probes were used to measure nutrient (NH ₄ ⁺ -N, NO ₃ ^? -N, and PO ₄ ^?3 -P) supply rates in the soil during incubation. Per unit of N added, urea tended to result in the greatest N₂O production, followed by wet distillers grain and thin stillage, with glycerol and dehydrated alfalfa resulting in the lowest N₂O production. Cumulative N₂O production increased with increasing the rate of N-containing amendments and was the highest at the high rate of UR treatment. Addition of urea with glycerol contributed to a higher rate of N₂O emission, especially at the low rate of glycerol. The DA and WDG resulted in the greatest evolution of CO₂ from the soil, with the thin stillage resulting in less CO₂ evolved per unit of N added. Addition of N fertilizer along with glycerol enhanced microbial activity and decomposition. The amendments had significant impacts on release of available nutrient, with the UR treatments providing the highest NO ₃ ^? -N supply rate. The TS treatments supplied the highest rate of NH ₄ ⁺ -N, followed by WDG compared to the other amendments. The WDG treatments were able to provide the greatest supply of PO ₄ ^?3 -P supply in comparison to the other amendments. Microbial N immobilization was associated with glycerol treatments applied alone. This study showed that the investigated biofuel by-products can be suitable soil amendments as a result of their ability to supply nutrients and N₂O emissions that did not exceed that of the conventional urea fertilizer.  相似文献