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311.
Bruce D. Whitaker Jacqueline F. Nock Christopher B. Watkins 《Postharvest Biology and Technology》2000,20(3):227
In a 2-year study, fruit from eight red- and eight yellow-skinned ‘White Angel’בRome Beauty’ hybrid selections were stored for 21 weeks at 0.5°C plus 1 week at 20°C and evaluated for the incidence and severity of superficial scald. Five red-skinned (R-03, R-20, R-22, R-48 and R-85) and three yellow-skinned (Y-26, Y-55 and Y-65) selections were examined in both seasons. Peel-tissue samples taken at 0, 7, 14 and 21 weeks of storage were analyzed for concentrations of α-farnesene and its conjugated trienol (CTol) oxidation products by HPLC with UV detection. Three red-fruited (R-44, R-48 and R-85) and five yellow-fruited (Y-38, Y-40, Y-55, Y-65 and Y-67) lines exhibited scald symptoms. The remaining lines (R-01, R-03, R-16, R-20, R-22, Y-07, Y-26 and Y-28) were free of scald. Overall, production of α-farnesene and accumulation of CTols were not closely correlated with scald susceptibility. Data for the selections most prone to scald, Y-65, Y-40 and R-44, were consistent with the proposed role of α-farnesene oxidation products in scald induction, but for Y-55 and R-48, which developed mild to moderate scald and accumulated very little CTols, the data conflicted with the α-farnesene oxidation–scald induction hypothesis. Also, scald-resistant lines Y-07 and R-22 produced high levels of α-farnesene and reached CTol concentrations comparable to those in several scald-susceptible lines. We conclude that if CTol do play a role in scald induction, there must be other mitigating factors of at least equal importance. Moreover, our findings support the proposal that oxidation products of α-farnesene are not essential for scald development in fruit with severely compromised antioxidative defenses, but free radicals and/or toxic volatiles generated by α-farnesene oxidation can exacerbate scald symptoms. 相似文献
312.
Cerebrospinal Fluid Analysis and Clinical Outcome of Eight Dogs With Eosinophilic Meningoencephalomyelitis 总被引:2,自引:1,他引:1
Laura L. Smith-Maxie DVM MSc Joane P. Parent DVM MVSc Jacqueline Rand BVSc DVSc Brian P. Wilcock DVM PhD AIan M. Norris DVM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1989,3(3):167-174
Eight dogs, 14 weeks to 5.5 years of age, had signs of diffuse or multifocal meningoencephalomyelitis. The total white cell counts of the cerebrospinal fluid (CSF) ranged from 11 to 5,550 cells/microliters; the percentage of eosinophils ranged from 21% to 98%. The total CSF protein content range was 19 to 1,430 mg/dl. On necropsy, two dogs had granulomatous encephalomyelitis due to protozoan infection. The other six dogs, of which three were Golden Retriever dogs, appeared to have an idiopathic eosinophilic meningoencephalitis; four of these dogs recovered. The significance of eosinophils in CSF and the possible emergence of a new encephalitic syndrome of dogs involving a hypersensitivity to an unknown agent is also discussed. 相似文献
313.
Helene H. Wagner Silke Werth Jesse M. Kalwij Jacqueline C. Bolli Christoph Scheidegger 《Landscape Ecology》2006,21(6):849-865
The process of recolonization after disturbance is crucial for the persistence and dynamics of patch-tracking metapopulations.
We developed a model to compare the spatial distribution and spatial genetic structure of the epiphytic lichen Lobaria pulmonaria within the perimeter of two reconstructed 19th century disturbances with a nearby reference area without stand-level disturbance.
Population genetic data suggested that after stand-replacing disturbance, each plot was colonized by one or a few genotypes
only, which subsequently spread clonally within a local neighborhood. The model (cellular automaton) aimed at testing the
validity of this interpretation and at assessing the relative importance of local dispersal of clonal propagules vs. long-distance
dispersal of clonal and/or sexual diaspores. A reasonable model fit was reached for the empirical data on host tree distribution,
lichen distribution, and tree- and plot-level genotype diversity of the lichen in the reference area. Although model calibration
suggested a predominance of local dispersal of clonal propagules, a substantial contribution of immigration of non-local genotypes
by long-distance dispersal was needed to reach the observed levels of genotype diversity. The model could not fully explain
the high degree of clonality after stand-replacing disturbance, suggesting that the dispersal process itself may not be stationary
but depend on the ecological conditions related to disturbance. 相似文献
314.
315.
Journal of Plant Diseases and Protection - The application of entomopathogenic fungi against weevils of the genus Otiorhynchus spp. might represent an environmentally friendly management option for... 相似文献
316.
Fernando Alferez Yolanda Lluch Jacqueline K. Burns 《Postharvest Biology and Technology》2008,49(1):69-76
The role of phospholipase A2 (PLA2) activity in development of postharvest peel pitting in mature ‘Fallglo’ tangerines [Bower citrus hybrid (Citrus reticulata Blanco × C. reticulata Blanco × C. paradisi Macf.) × Temple (C. reticulata Blanco × Citrus sinensis L.)] and ‘Navel’ oranges (Citrus sinensis L. Osbeck) was investigated. Changes in RH from 30% to 90% followed by fruit waxing increased electrolyte leakage and PLA2 activity in flavedo, and induced pitting. Treatment with an aqueous dip of aristolochic acid (AT), a specific inhibitor of secretory phospholipase A2 (sPLA2) activity, immediately before transfer from 30% to 90% RH storage, markedly reduced peel pitting symptoms. Five genes encoding various phospholipase As isolated from citrus (three patatin-like and two sPLA2-like sequences) differentially accumulated in healthy areas, areas with developing lesions and necrotic lesions of disordered fruit. Other PLA2, phospholipase C, and phospholipase D inhibitors also reduced peel pitting; however, PLA2 inhibitors were the most effective in preventing the disorder. In addition, phospholipase inhibitors promoted fruit decay, suggesting that innate resistance is impacted by phospholipase action. Together, the results provide evidence for involvement of phospholipase activity in development of postharvest peel pitting symptoms in citrus fruit. 相似文献
317.
Pernilla Gransson Pl Axel Olsson Jacqueline Postma Ursula Falkengren-Grerup 《Soil biology & biochemistry》2008,40(9):2260
Acidic soils are harsh environments for plants. One of the major problems is the potential toxicity of aluminium (Al) and hydrogen ions at a pH below 5; another is the shortage of nutrients usually accompanying soil acidity. The aim of this study was to elucidate the relationship between arbuscular mycorrhizal (AM) colonisation and soil acidity (measured by pH and Al concentration) in order to evaluate the possibility that AM fungi facilitate the existence of plants on acidic soils. We sampled tussocks of four grass species, Elymus caninus, Poa nemoralis, Deschampsia cespitosa and Deschampsia flexuosa, together with samples of the surrounding soil, in oak forests of varying soil pH in southern Sweden. We determined pH, easily reacting Al (Alr), extractable Al (AlBaCl2) and phosphate in the soil samples, analysed the shoots for Al and phosphorous and quantified the degree of AM and fine endophyte (FE) colonisation in the roots. E. caninus was found on the least acidic soils and had the highest AM colonisation of all the species studied, while D. flexuosa, which was found on the most acidic soils, had the lowest AM colonisation. P. nemoralis and D. cespitosa were intermediate with respect to pH and AM colonisation. The colonisation of AM fungi exceeded FE colonisation for E. caninus and P. nemoralis, while the opposite was true for the two Deschampsia species. Our results indicated a negative relationship between Alr and the degree of AM colonisation at the within-species level. The low colonisation of AM fungi on acidic soils may to some extent be explained by a sensitivity of AM fungi to Alr: this parameter showed a stronger negative association with AM colonisation than did pH and AlBaCl2. We hypothesize that Al toxicity is a critical factor for plant nutrition in forest soils through the impact on symbiotic fungi. 相似文献
318.
Rebekka R.E. Artz Stephen J. Chapman A.H. Jean Robertson Jacqueline M. Potts Fatima Laggoun-Défarge Sébastien Gogo Laure Comont Jean-Robert Disnar Andre-Jean Francez 《Soil biology & biochemistry》2008,40(2):515-527
Vegetational changes during the restoration of cutover peatlands leave a legacy in terms of the organic matter quality of the newly formed peat. Current efforts to restore peatlands at a large scale therefore require low cost and high throughput techniques to monitor the evolution of organic matter. In this study, we assessed the merits of using Fourier transform infrared (FTIR) spectra to predict the organic matter composition in peat samples at various stages of peatland regeneration from five European countries. Using predictive partial least squares (PLS) analyses, we were able to reconstruct peat C:N ratio and carbohydrate signatures with reasonable accuracy, but not the micromorphological composition of vegetation remains. Despite utilising different size fractions, both carbohydrate (<200 μm fraction) and FTIR (bulk soil) analyses report on the composition of plant cell wall constituents in the peat and therefore essentially reveal the composition of the parent vegetational material. The accuracy of the FTIR-based PLS models for C:N ratios and carbohydrate signatures was adequate to allow for their use as initial screening tools in the evaluation of the present and future organic matter composition of peat during monitoring of restoration efforts. 相似文献
319.
320.
Prisca Noble Bernard Collin Jacqueline Lecomte-Beckers Adrien Magnée Jean M. Denoix Didier Serteyn 《Veterinary journal (London, England : 1997)》2010,183(2):148-152
This study describes an equine joint friction test using a cartilage-on-cartilage arrangement and investigates the influence of age and load on the frictional response. Osteochondral plugs were extracted from equine shoulder joints (2–5 years, n = 12; 10–14 years, n = 15), and mounted in a pin-on-disc tribometer. The frictional response was then measured under constant conditions (2 N; 20 °C; 5 mm/s), and with increasing load (2 N, 5 N, 10 N). In all experiments, the friction coefficient of young cartilage was significantly (P < 0.001) smaller than obtained from old cartilage, while the application of a greater load resulted in a significant (P < 0.001) decrease in friction coefficient only in old cartilage. It was concluded that cartilage ageing was responsible for an increase in friction coefficient under these experimental conditions. Moreover, where young cartilage lubrication remained stable, cartilage ageing may have been responsible for lubrication regime change. The cartilage-on-cartilage model could be used to better understand lubrication regime disturbances in healthy and diseased equine joints, and to test the efficacy of various bio-lubricant treatments. 相似文献