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11.
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Shoot cultures were established from nodal explants of 3 pear cultivars by subculture on Murashige and Skoog medium containing mixtures of 3 cytokinins. Zeatin and 6·(γ,γ-dimethylallylamino)purine were both supplied at 10 μM and benzyladenine as follows: ‘William's Bon Chrétien’, 6 μM; ‘Packham's Triumph’, 8 μM; ‘Beurré Bosc’, 10 μM. Production of axillary shoots was greater by basal explants (4–6) comprising the remnants of the previous subculture than by apical explants (2–3) comprising the distal parts of extension shoots. Up to 80% of microcuttings of all cultivars formed roots in vitro with either γ-indolebutyric acid, 10 μM, or α-naphthaleneacetic acid, 10 μM, and approximately 50% of rooted microcuttings were successfully established as container-grown plants. Use of aseptic methods for producing own-rooted pears is discussed in relation to fruit growing and fruit improvement.  相似文献   
13.
ABSTRACT Pseudomonas fluorescens B5 and Bacillus subtilis MBI 600 colonized sugar beet seedlings at matric potentials of -7 x 10(3), -140 x 10(3), and -330 x 10(3) Pa and under five temperature regimes ranging from 7 to 35 degrees C, with diurnal fluctuations of 5 to 22 degrees C. No interaction between matric potential and temperature was observed. In situ bioluminescence indicated physiological activity of Pseudomonas fluorescens B5. Colonization of the root at >/=4 cm below the seed decreased at very low matric potential (-330 x 10(3) Pa). Total population size of Pseudomonas fluorescens B5 per seedling was significantly increased at -140 x 10(3) Pa. However, matric potential had no significant effect on the population density of Pseudomonas fluorescens per gram of root fresh weight and did not affect the distribution of the population down the root. Total population size per seedling and downward colonization by Pseudomonas fluorescens B5 were significantly reduced at high temperatures (25 to 35 degrees C). Maximum colonization down the root occurred at intermediate temperature (15 degrees C) at both matric potentials (-7 x 10(3) and -140 x 10(3) Pa). Addition of B. subtilis MBI 600 to the seed had no effect on rhizosphere populations of Pseudomonas fluorescens B5. Populations of B. subtilis MBI 600, which consisted largely of spores, were slightly reduced at lower matric potentials and were not affected by temperature. Survival and dry weight of plants in soils infested with Pythium spp. decreased with increasing soil temperature and matric potential, indicating an increase in disease pressure. However, there was no significant interaction between the two factors. At -330 x 10(3) Pa, soil dryness but not Pythium infection was the limiting factor for plant emergence. At temperatures of 7 to 25 degrees C and matric potentials of -7 x 10(3) to 120 x 10(3) Pa, treatment with Pseudomonas fluorescens B5 increased plant survival and dry weight. At 7 degrees C and -120 x 10(3) Pa, there was almost complete emergence of seeds treated with Pseudomonas fluorescens B5. Antagonistic activity of Pseudomonas fluorescens B5 decreased with increasing soil temperature and decreasing matric potential. At 25 to 35 degrees C and -7 x 10(3) Pa, no effect was observed. In regimes with different day and night temperatures, the maximum (day) temperature was decisive for disease development and antagonistic activity. B. subtilis MBI 600 displayed no significant antagonistic effect against Pythium ultimum and did not influence the performance of Pseudomonas fluorescens B5 in combined inocula.  相似文献   
14.
OBJECTIVE: To describe a modified ventral stabilization technique for surgical management of atlantoaxial subluxation in dogs and to evaluate the outcome. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Nineteen client-owned dogs. METHODS: Medical records of 19 dogs with a radiographic diagnosis of atlantoaxial subluxation surgically managed by a modified ventral fixation technique (cortical screws, Kirschner wires, polymethylmethacrylate) were reviewed. Data on pre- and post-operative neurologic status, surgical technique, and complications were retrieved. Follow-up evaluation was performed at approximately 1 month. Telephone interview of the owner was used for long-term assessment (median follow-up for 17 surviving dogs was 10.5 months). RESULTS: Adequate reduction and stabilization was achieved in all dogs based on radiographic assessment immediately after surgery. Improved neurologic outcome occurred in 16 dogs at 1 month and in 15 dogs at follow-up; 2 dogs died of post-operative complications within 24 hours of surgery. One dog was euthanatized at the owners' request because of recurrent neck pain associated with implant failure after 1 month. Two dogs required surgery to remove broken and migrated implants, but further stabilization was not necessary. CONCLUSIONS: Adequate stabilization and improved neurologic outcome was achieved in most dogs. However, on account of the small size of the study and the variable neurologic signs of the dogs on admission, the surgical technique described could not be compared to those previously reported. CLINICAL RELEVANCE: The surgical technique described is an effective means of surgical treatment for atlantoaxial subluxation.  相似文献   
15.
Extract

The time has come, perhaps, to speak of things other than the biological in relation to animal life.  相似文献   
16.
Objective— To investigate the development of gingival hyperplasia in dogs after renal transplantation and administration of microemulsified cyclosporine A (MCsA).
Study Design— Experimental study.
Animals— Healthy adult mongrel dogs (n=5).
Methods— As part of study on renal transplantation, dogs administered MCsA (20 mg/kg/day), azathioprine, and prednisolone to prevent graft rejection were monitored for development of gingival changes. Prednisolone was discontinued after 3 months. MCsA dose was adjusted to maintain whole blood trough concentration of 400–700 ng/mL. Gingival change was evaluated by weekly examination and photodocumentation, and gingival biopsy for histopathology was performed at 28 weeks.
Results— One dog was lost because of acute graft rejection. Gingival hyperplasia developed in 3 of 4 dogs. The earliest gingival changes occurred in the interdental papillae at 20 weeks after transplantation. On histopathology, the underlying connective tissue was thickened and contained increase numbers of fibroblasts and inflammatory infiltrates.
Conclusions— Long-term immunosuppression with an MCsA-based treatment likely induces substantial gingival hyperplasia when therapeutic, immunosuppressive blood levels of MCsA were maintained for 32 weeks.
Clinical Relevance— MCsA is used for immune-mediated diseases and preventing rejection after transplant in dogs. MCsA blood levels, and gingival hyperplasia should be monitored by routine examination of the interdental papilla in dogs administered MCsA for long periods.  相似文献   
17.
Fossil cephalopods are frequently encrusted by epibionts; however, determining whether encrustation occurred prior to or post‐mortem to the host, and whether the final environment of deposition corresponds to the habitat of encrustation is complex. The present paper describes cirripede epibionts, their calcareous bases and their attachment scars on 6 post‐mortem shells of Nautilus macromphalus, collected from deep water off New Caledonia. The cirripedes have left both cemented calcareous bases of Hexelasma and scars associated with bioerosion and discoloration produced by verrucomorph barnacles. Live cirripedes included a Metaverruca recta, with articulated opercular plates and organic tissue (on a shell that had been exposed on the sea floor for at least 150 years), and specimens of Hexelasma velutinum, one of which was partly attached to an internal surface of a shell. The disposition of verrucomorphs indicates that most Nautilus shells were colonized post‐mortem rather than during a floating stage. However, as cirripedes are known to have colonized living Nautilus, some Hexelasma, preserved only as calcareous eroded bases, may represent specimens that settled on a living Nautilus. The degree of bioerosion and discoloration induced by verrucomorph barnacles varies according to the surface preservation of Nautilus shells, with deeper and discolored traces preserved on old and degraded shells. Traces made by verrucomorphs described here are ellipsoidal and a new ichnotaxon, Anellusichnus ellipticus, is proposed to accommodate them. Importantly, verrucomorphs and other cirripede taxa with membranous bases that were attached to pristine shells may not leave any substantial scars, and, thus, will be difficult to detect in the fossil record.  相似文献   
18.
19.
Zymoseptoria tritici, the causal agent of septoria tritici blotch (STB), remains a significant threat to European wheat production with the continuous emergence of fungicide resistance in Z. tritici strains eroding the economic sustainability of wheat production systems. The life cycle of Z. tritici is characterized by a presymptomatic phase (latent period, LP) after which the pathogen switches to an aggressive necrotrophic stage, when lesions bearing pycnidia quickly manifest on the leaf. As minimal knowledge of the possible role of the LP in supporting STB resistance/susceptibility exists, the goal of this study was to investigate the spatial and temporal association between the LP and disease progression across three locations (Ireland – Waterford, Carlow; UK – Norwich) that represent commercially high, medium and low STB pressure environments. Completed over two seasons (2013–2015) with commercially grown cultivars, the potential of the LP in stalling STB epidemics was significant as identified with cv. Stigg, whose high level of partial resistance was characterized by a lengthened LP (c. 36 days) under the high disease pressure environment of Waterford. However, once the LP concluded it was followed by a rate of disease progression in cv. Stigg that was comparable to that observed in the more susceptible commercial varieties. Complementary analysis, via logistic modelling of intensive disease assessments made at Carlow and Waterford in 2015, further highlighted the value of a lengthened LP in supporting strong partial resistance against STB disease of wheat.  相似文献   
20.
Insight into pathogen population dynamics provides a key input for effective disease management of the potato late blight pathogen Phytophthora infestans. Phytophthora infestans populations vary from genetically complex to more simple with a few clonal lineages. The presence or absence of certain strains of P. infestans may impact the efficacy of fungicides or host resistance. Current evidence indicates that genetically, the Irish populations of P. infestans are relatively simple with a few clonal lineages. In this study, P. infestans populations were genetically characterized based on samples collected at the national centre for potato breeding during the period 2012–16. The dominance of clonal lineages within this P. infestans population was confirmed and the potential selection pressure of fungicide treatment (2013–15) and host resistance (2016) on this clonal P. infestans population was then investigated. It was found that fungicide products did not notably affect the genetic structure of sampled populations relative to samples from untreated control plants. In contrast, samples taken from several resistant potato genotypes were found to be more often of the EU_13_A2 lineage than those taken from control King Edward plants or potato genotypes with low resistance ratings. Resistant potato varieties Sarpo Mira and Bionica, containing characterized R genes, were found to strongly select for EU_13_A2 strains.  相似文献   
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