Association of double-stranded RNA with whitefly-mediated silvering in squash     

N. BHARATHAN  W. R. GRAVES  K. R. NARAYANAN  D. J. SCHUSTER†  H. H. BRYAN  R. T. McMILLAN JR 《Plant pathology》1990,39(3):530-538

A disorder of unknown aetiology appearing as silvering on squash (Cucurbita pepo) leaves has become prevalent in south Florida. Typical symptoms, observed after 2 weeks of exposure to adults of Bemisia tabaci , the sweet potato whitefly (SPWF) include vein clearing followed by silvering of whole leaves. Fruits from affected plants are blanched or streaked longitudinally. The silverleaf syndrome was not mechanically transmissible when crude extracts of symptomatic leaves were used as inoculum. Two sizes of double-stranded RNA (dsRNA) of c. 4.6 and 4.2 kilobase pairs (kbp) were consistently observed in leaf extracts of caged, whitefly-infested, symptomatic plants. In contrast, caged plants not exposed to whiteflies showed no symptoms and contained no detectable dsRN A. In addition, squash plants exposed to SPWF colonies from California neither developed silverleaf symptoms nor contained any dsRNA. Double-stranded RNA could also be readily detected in whitefly-infested yellow summer squash and zucchini from the field. However, asymptomatic eggplant and watermelon infested with SPWF from nearby fields did not contain detectable dsRNA. Dot-spot hybridization assays using an RNA-specific probe detected homologous sequences in both adults and nymphs of SPWF that induced silverleaf symptoms but not in adults and nymphs of SPWF that could not induce silverleaf symptoms. These results, along with the non-endogenous nature of the detected dsRNA suggest that the dsRNA is or is associated with the causal agent of whitefly-mediated leaf silvering in squash.  相似文献   

Carbon monoxide toxicity: a case series     

Allyson C. Berent  DVM    Jeffrey Todd  DVM    Jennifer Sergeeff  DVM  DACVIM    Lisa L. Powell  DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2005,15(2):128-135

Objective: To describe diagnostics, therapy, and sequelae of acute carbon monoxide (CO) toxicity because of a motor vehicle generator in 4 dogs and 2 cats. Series summary: Four dogs and 2 cats presented for recumbency, disorientation, dyspnea, and stiffness after an estimated 6–8 hour exposure to exhaust from a generator. Diagnostics included a serum carboxyhemoglobin levels evaluation, arterial blood gas analysis, pulse oximetry readings, and blood pressure measurements. Initial therapy included oxygen (O₂) administration, intravenous bronchodilators, fluids, and a hemoglobin‐based O₂ carrying (HBOC) molecule. Following administration of the HBOC, 4 of the 6 animals showed dramatic clinical improvement. Two weeks after hospital discharge, the owner reported potential hearing deficits in all animals. Brain auditory evoked response (BAER) tests were conducted in all surviving animals and some degree of hearing impairment was documented in all cases, with complete clinical resolution noted 6 weeks later. Unique information provided: This report describes the therapeutic use of an HBOC in acute isolated CO toxicity (i.e. without the complications of smoke inhalation). In addition, delayed nervous system dysfunction was documented in all surviving animals.  相似文献   

Synthesis and herbicidal activity of some potent bicyclic ether herbicides     

Wendy S. Taylor  James E. Powell  Eileen L. Marsilii  Kathryn J. Leep 《Pest management science》1995,44(1):85-87

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Phytotoxicity of Methyl Bromide to Chrysanthemum Cuttings     

K. G. Gostick  D. F. Powell 《Plant pathology》1971,20(3):136-141

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Sporotrichosis in a dog   总被引：2，自引：0，他引：2  

G Koehne  H S Powell  R I Hail 《Journal of the American Veterinary Medical Association》1971,159(7):892-894

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Studies on the mechanism of vaccinal immunity to Marek''s disease   总被引：1，自引：0，他引：1  

L.N Payne  P.C Powell  M.C Rennie  L.J.N Ross 《Comparative immunology, microbiology and infectious diseases》1978,1(1-2):31-36

Current knowledge of the nature of the antigens and of the host immune responses in vaccinal immunity to Marek's disease is reviewed. It is suggested that a two-step mechanism of resistance operates. The first step involves humoral and cell-mediated responses directed against viral antigens; the second step occurs after challenge with Marek's disease virus and consists of cellmediated responses directed against tumour cells.  相似文献   

Cloning,expression, purification,and biological activity of five feline type I interferons   总被引：1，自引：0，他引：1  

Wonderling R  Powell T  Baldwin S  Morales T  Snyder S  Keiser K  Hunter S  Best E  McDermott MJ  Milhausen M 《Veterinary immunology and immunopathology》2002,89(1-2):13-27

Type I interferons (IFN) are important mediators of the host defense against viral infections in mammals. In humans multiple subtypes of IFN-alpha exist, most of which possess antiviral activity. Little is known about the type I IFN genes in cats and the role they may play in feline immunological responses to viruses. We have isolated cDNAs encoding five feline IFN-alpha (feIFN) subtypes that share from 95 to 99% amino acid sequence identity. FeIFN-alpha5 has five additional amino acids inserted at position 139, which are not present in the other four subtypes. Sequence identity of the feIFN proteins encoded by the five clones compared to human IFN-alpha2 is approximately 60%. Unlike most of the human subtypes, each of the five feline IFN sequences has an N-glycosylation recognition site. Expression of all five feIFN-alpha subtypes in Chinese hamster ovary (CHO) cells was confirmed by Western blot analysis, and all resulting proteins were glycosylated. The antiviral activity of each feIFN-alpha subtype produced in transiently transfected CHO cell cultures was tested in vitro. In addition, subtype feIFN-alpha6 was expressed in the yeast, Pichia pastoris. The resulting secreted mature recombinant protein was purified and demonstrated significant antiviral activity and induction of 2',5'-oligoadenylate synthetase activity in vitro.  相似文献   

Xylitol intoxication associated with fulminant hepatic failure in a dog     

Jeffrey M. Todd  DVM    Lisa L. Powell  DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2007,17(3):286-289

Objective: To describe a case of xylitol intoxication causing fulminant hepatic failure in a dog. Case summary: A 2.5‐year‐old castrated male English Springer Spaniel weighing 26 kg, was presented after ingestion of half of a loaf of bread containing the sweetener xylitol. Toxic effects of the xylitol in this dog included vomiting, mild hypoglycemia and fulminant hepatic failure. Clinical management of acute hepatic failure and subsequent coagulopathy with supportive care and fresh frozen plasma is described. The dog was discharged 3 days after admission after a full clinical recovery. New or unique information provided: This paper describes the clinical consequence and successful treatment of fulminant hepatic failure in a dog following ingestion of xylitol.  相似文献   

Simulation study of the competitive ability of erect, semi-erect and prostrate cowpea (Vigna unguiculata) genotypes   总被引：1，自引：1，他引：1  

G WANG  ME MCGIFFEN JR  JL LINDQUIST†  JD EHLERS  & I SARTORATO‡ 《Weed Research》2007,47(2):129-139

Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterised, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the competition of cowpea genotypes and sunflower than companion field experiments for the competition of cowpea and purslane. The validated simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habit on final biomass production of cowpea and sunflower. The model suggested that erect growth habit was more competitive than semi‐erect and prostrate growth habit, when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass. Our simulation approach is suggested as a method for crop breeders to gauge the likely success of selection for competitive crops before undertaking expensive long‐term breeding experiments.  相似文献   

Successful medical treatment of splenic abscesses in a horse     

CM STEEL  RA LONSDALE  JR BOLTON 《Australian veterinary journal》1998,76(8):541-542

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