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101.
Lester GE Hodges DM Meyer RD Munro KD 《Journal of agricultural and food chemistry》2004,52(8):2167-2173
Activities of the antioxidant enzymes ascorbate peroxidase, catalase, dehydroascorbate reductase, glutathione reductase, guaiacol peroxidase, monodehydroascorbate reductase, and superoxide dismutase were assayed in honeydew (Cucumis melo L.) fruit and spinach (Spinacia oleracea L.) leaves either as fresh, frozen to -80 degrees C, frozen in liquid nitrogen, freeze-dried, or acetone powder, representing the various ways tissues are treated prior to enzyme extraction. Treated tissues were analyzed following treatment or stored for up to 8 weeks at -80 degrees C. Enzyme activities in fruit frozen with or without liquid nitrogen and leaves frozen with or without liquid nitrogen or freeze-dried were equal to those of fresh tissue. Enzyme activities in freeze-dried or acetone-powdered fruit and leaves and in acetone-powdered tissues were significantly higher or lower than those in fresh tissue. Enzyme activities in both tissues frozen with or without liquid nitrogen and stored for 8 weeks at -80 degrees C changed little; those in freeze-dried and acetone-powdered tissues, however, significantly increased/decreased over the same period. Fresh tissue should be used in antioxidant enzyme assays, but if storage is necessary, tissues should be placed directly into a -80 degrees C freezer. 相似文献
102.
Kathleen G. Haynes Xinshun Qu Barbara J. Christ 《American Journal of Potato Research》2014,91(3):254-259
Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum (phu-stn). The objective of this study was to determine if resistance to late blight could be improved by recurrent maternal half-sib selection in the phu-stn population. Four clones from each of 72 maternal half-sib families plus the check cultivar ‘Atlantic’ were evaluated for late blight resistance in replicated field trials in Pennsylvania. The most late blight resistant clone from each of the 72 families was randomly intermated to advance the population. The cycle 1, 2, and 3 populations were evaluated in 1996–1997, 2003–2004, and 2009–2010, respectively. Percent infected foliage was recorded several times towards the end of the growing season and used to compute area under the disease progress curve (AUDPC). Mean AUDPC was 652 (cycle 1), 556 (cycle 2), and 276 (cycle 3), whereas the mean AUDPC of ‘Atlantic’ ranged from 775 to 863 each cycle. Narrow-sense heritability for resistance was estimated as 0.78, 0.77, and 0.80 in cycles 1, 2, and 3, respectively. Recurrent maternal half-sib selection continues to improve the levels of resistance to late blight in this diploid population with no adverse effect on the amount of additive genetic variance. Additional improvements for late blight resistance are likely to occur if this approach is continued. 相似文献
103.
Samer AbuBakr Simone L. Macmil Mark A. Nanny Kathleen E. Duncan 《Soil biology & biochemistry》2008,40(8):2055-2062
Enzymatic transformation of humic acids (HA), fulvic acids (FA) and indole was examined using naphthalene 1,2-dioxygenase (NDO). NDO was used as a model for dioxygenase enzymes found in various microbial species. Indole was used as a model substrate for NDO-catalyzed reactions resulting in condensation products. Although NDO is not classified as a soil enzyme, all HA and FA tested were susceptible to NDO-induced transformation. The extent of NDO-specific NADH oxidation in solutions containing HA and FA paralleled the percent aromaticity of the HA and FA. Furthermore, the UV–Vis absorptive properties of NDO-treated HA and FA were altered in a manner suggesting condensation reactions similar to the formation of indigo from indole. Condensation reactions were enhanced in NDO-treated mixtures containing indole and an FA. NDO retained activity for 2 weeks under ambient conditions, and retained some enzymatic activity for 9 days based on detection of specific metabolites by HPLC, suggesting prolonged extracellular activity. Humic substances have not previously been known to be substrates for dioxygenases; even more significant was that dioxygenase enzymes can facilitate condensation reactions between indole-like functional groups well-known to be present in HA and FA. These results illustrate how dioxygenases can be potential humic-modifying enzymes when released into the environment upon microbial death and concurrent cell lysis which could alter the bioavailability of organic contaminants associated with dissolved organic matter through specific modulation of enzyme activity involving substrate competition. 相似文献
104.
Kathleen A Linn Alison S Templer Joanne R Paul-Murphy Robert T O'Brien Barry K Hartup Julia A Langenberg 《Journal of zoo and wildlife medicine》2003,34(2):144-152
Tendon ossification in the crus and tarsometatarsal regions of cranes makes ultrasonography difficult everywhere except for joints, where ossification is absent. Normal ultrasonographic anatomy of the adult Florida sandhill crane (Grus canadensis pratensis) intertarsal joint is described on the basis of ultrasonography that was performed on the limbs of a cadaver, which were dissected and cross-sectioned subsequently, to correlate ultrasonographic images with anatomic structures. Intertarsal joints of five normal sandhill cranes and two cranes with known intertarsal abnormalities were then imaged bilaterally in transverse and sagittal planes. Ultrasonographic imaging can be used to evaluate the soft-tissue structures on the dorsal and plantar aspects of the intertarsal joint of cranes, and it is a useful adjunct to physical and radiographic examination for localizing injuries to this area. 相似文献
105.
106.
David C. Dorman DVM PhD Kathleen A. Coddington MS DVM Ralph C. Richardson DVM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1990,4(5):254-257
Twenty-six cases of accidental 5-fluorouracil (5-FU) ingestions by dogs were reviewed from phone calls to the Illinois Animal Poison Information Center. Cases were collected from January 1, 1987 to December 31, 1988. Of the 26 calls involving 5-FU exposures, 12 were classified as "toxicosis," 13 as "suspected toxicosis," and one as "exposure." Dogs were the only species involved in 5-FU cases received during this time. Accurate estimates of the amount of 5-FU ingested by dogs could be made in 17 cases. Ingestion of more than 20 mg/kg of 5-FU was associated with the development of toxicosis. None of the 12 dogs that ingested oral doses in excess of 43 mg/kg (estimated) survived. Clinical signs associated with 5-FU poisoning in the dog were death, seizures, vomiting (with and without blood), tremors, diarrhea (with and without blood), ataxia, and depression. Clinical signs generally developed within 45 to 60 minutes after exposure, and deaths occurred 6 to 16 hours after ingestion. 相似文献
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109.
Flow cytometric characterization of peripheral blood leukocyte populations of 3 neotropical snake species: Boa constrictor,Bothrops jararaca,and Crotalus durissus 下载免费PDF全文
110.
Jean M. Daniels Alicia S.T. Robbins Weston R. Brinkley Kathleen L. Wolf John M. Chase 《Urban Forestry & Urban Greening》2014,13(2):285-289
Urban forestry professionals are increasingly challenged to find cost-effective strategies for resource conservation and management. Many organizations partner with citizen groups to host events that enlist volunteers to perform stewardship tasks like tree planting and trail maintenance. These volunteer programs incur costs to both the managing agency and partners, such as staffing, tools, and transportation. Volunteers contribute uncompensated time and expertise. Little is known about these contributions, yet citizen stewards and host groups represent an important human dimension of urban forest management. Using a survey administered to volunteers and host organizations at restoration events in King County Parks, WA, USA, we developed a cost-based approach to estimate the value of stewardship activities that occurred in the spring field season of 2011. Expenditures included volunteer and event host time and direct cost of traveling to and from events, on-site labor, equipment, and preparation costs. Results suggest that contributions made by volunteers and hosts are significant; the combined costs associated with the 17 sampled events was approximately $35,700. These efforts represent a small subset of the more than 1000 volunteer environmental stewardship activities that take place annually in King County. 相似文献