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91.
Yu-Kuang H. Chen Jiwan P. Palta John B. Bamberg Heiyoung Kim Geraldine T. Haberlach John P. Helgeson 《Euphytica》1999,107(1):1-8
The expression of freezing tolerance was characterized in interspecific somatic hybrids between S. tuberosum (tbr) and two
cold-hardy wild species, S. brevidens (brd) and S. commersonii (cmm). The nonacclimated freezing tolerance (NA) and acclimation
capacity (ACC, increase in freezing tolerance in response to low nonfreezing temperature), two main genetic components of
freezing tolerance, were evaluated separately. In contrast to cmm, which exhibited excellent NA and ACC, the freezing tolerance
of brd was mainly due to ACC. However, the ACC of brd was only moderately expressed in the somatic hybrids. The NA of cmm
was also suppressed in combination with tbr genomes. However, with acclimation, some of the tbr (+) cmm somatic hybrids achieved
freezing tolerance comparable to pure hardy species such as brd used in this study. Analysis of chloroplast DNA type by RFLP
markers revealed no significant difference in ACC between somatic hybrids carrying chloroplasts from either tbr or cmm. The
reasons for the reduced expression of freezing tolerance from either the brd or cmm parent and the utilization of these somatic
hybrids in breeding programs are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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John P. Helgeson Geraldine T. Haberlach Mark K. Ehlenfeldt Greg Hunt John D. Pohlman Sandra Austin 《American Journal of Potato Research》1993,70(6):437-452
Hexaploid somatic hybrids have been obtained by fusion of protoplasts fromSolanum brevidens (PI 218228, 2x = 2n = 24) andS. tuberosum (PI 203900 or cv. Russet Burbank; 2x = 4n = 48). In the work reported here, pentaploid progeny derived from sexual crosses between the somatic hybrids and the potato cultivar, Katahdin were assessed for transfer of disease resistances and improvement of agronomic traits. Segregation was noted in disease resistances to race 0 ofPhytophthora infestans and to tuber soft rot caused byErwinia spp., indicating that sexual transfer of traits captured by protoplast fusion had occurred. The pentaploid progeny showed substantial variation in and often improvement of some agronomic traits as compared to the somatic hybrids. The results indicate that interspecific somatic hybridization can produce material with potential for use in a potato breeding program 相似文献
94.
Cameron RG Luzio GA Vasu P Savary BJ Williams MA 《Journal of agricultural and food chemistry》2011,59(6):2717-2724
Methyl ester distribution in pectin homogalacturonan has a major influence on functionality. Enzymatic engineering of the pectin nanostructure for tailoring functionality can expand the role of pectin as a food-formulating agent and the use of in situ modification in prepared foods. We report on the mode of action of a unique citrus thermally tolerant pectin methylesterase (TT-PME) and the nanostructural modifications that it produces. The enzyme was used to produce a controlled demethylesterification series from a model homogalacturonan. Oligogalacturonides released from the resulting demethylesterified blocks introduced by TT-PME using a limited endopolygalacturonase digestion were separated and quantified by high-pressure anion-exchange chromatography (HPAEC) coupled to an evaporative light-scattering detector (ELSD). The results were consistent with the predictions of a numerical simulation, which assumed a multiple-attack mechanism and a degree of processivity ~10, at both pH 4.5 and 7.5. The average demethylesterified block size (0.6-2.8 nm) and number of average-sized blocks per molecule (0.8-1.9) differed, depending upon pH of the enzyme treatment. The mode of action of this enzyme and consequent nanostructural modifications of pectin differ from a previously characterized citrus salt-independent pectin methylesterase (SI-PME). 相似文献
95.
Boston SE Higginson G Monteith G 《Journal of the American Animal Hospital Association》2011,47(5):336-341
The objective of this retrospective study was to evaluate the presence of concurrent splenic and cardiac hemangiosarcoma (HSA). Dogs were divided into two groups: group 1 included 23 dogs with splenic HSA, and group 2 included 31 dogs with a cardiac HSA. All dogs were fully assessed for metastasis with thoracic radiography, abdominal and/or cardiac ultrasound, and/or postmortem examination. Two dogs (8.7%) in group 1 had a concurrent cardiac mass. Neither of these dogs had pericardial effusion, and both were golden retrievers. Thirteen of the dogs in group 1 presented with a hemoabdomen. Concurrent intra-abdominal metastasis was noted in seven dogs. In group 2, 9/31 (29%) of the dogs had a concurrent splenic HSA, and 13/31 (42%) of the dogs had evidence of metastasis to another site. There was a significant association between age and the presence of nonsplenic metastasis (odds ratio, 0.457). The rate of concurrent right atrial mass detected by cardiac ultrasound in dogs with splenic HSA was 8.7%, which is less than previously reported. For dogs with right atrial HSA, the risk of metastasis to nonsplenic sites decreases with age. 相似文献
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99.
Jana Baron Abdelghani Bin-Tarif Rebecca Herbert Lorraine Frost Geraldine Taylor Michael D Baron 《Veterinary research》2014,45(1):22
Peste des petits ruminants is a viral disease of sheep and goats that has spread through most of Africa as well as the Middle East and the Indian subcontinent. Although, the spread of the disease and its economic impact has made it a focus of international concern, relatively little is known about the nature of the disease itself. We have studied the early stages of pathogenesis in goats infected with six different isolates of Peste des petits ruminants virus representing all four known lineages of the virus. No lineage-specific difference in the pathogenicity of the virus isolates was observed, although there was evidence that even small numbers of cell culture passages could affect the degree of pathogenicity of an isolate. A consistent reduction in CD4+ T cells was observed at 4 days post infection (dpi). Measurement of the expression of various cytokines showed elements of a classic inflammatory response but also a relatively early induction of interleukin 10, which may be contributing to the observed disease. 相似文献
100.
Sheath blight (ShB) disease, caused by Rhizoctonia solani, is an economically important rice disease worldwide, especially in intensive production systems. Several studies have been
conducted to identify sources for ShB resistance in different species of rice, including local accessions and landraces. To
date, none of the genotypes screened are immune to ShB, although variation in levels of resistance have been reported. Several
quantitative trait loci (QTL) for ShB resistance have been identified using mapping populations derived from indica or japonica rice. A total of 33 QTL associated with ShB resistance located on all 12 rice chromosomes have been reported, with ten of
these co-localizing with QTL for morphological attributes, especially plant height, or for heading date. Sixteen QTL, from
the same or differing genetic backgrounds, have been mapped at least twice. Of these, nine QTL were independent of morphological
traits and heading date. We hypothesize that two main, distinct, mechanisms contribute to ShB resistance: physiological resistance
and disease escape. Strategies to improve our understanding of the genetics of resistance to ShB are discussed. 相似文献