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排序方式: 共有87条查询结果,搜索用时 15 毫秒
1.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
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Tissa Senaratna Bryan D. McKersie Stephen R. Bowley 《In vitro cellular & developmental biology. Plant》1990,26(1):85-90
Summary The use of somatic embryos from cell culture systems in the clonal propagation of plants would be greatly facilitated if the
somatic embryos could be dried and stored in a dormant state similar to true seeds. A cell culture system was developed for
alfalfa (Medicago sativa L.) line RL34 which gave high yields of somatic embryos in an approximately synchronized pattern. These somatic embryos were
treated with abscisic acid (ABA) at the cotyledonary stage of development to induce desiccation tolerance. With no visual
preselection, approximately 60% of the dried embryos converted into plants upon reimbibition. When high quality embryos were
selected prior to drying, 90 to 100% conversion rates were observed. The timing of the application of ABA in terms of embryo
development was critical with an optimum being at cotyledonary stage spanning approximately 4 days; thus, synchronized embryo
development is required for optimal expression in bulk samples. The vigor of the seedlings from dried somatic embryos was
greater than those from embryos which had not been dried, but remained substantially lower than those from true seeds. 相似文献
5.
Water-Deficit Tolerance and Field Performance of Transgenic Alfalfa Overexpressing Superoxide Dismutase 总被引:29,自引:1,他引:28 下载免费PDF全文
Transgenic alfalfa (Medicago sativa) expressing Mn-superoxide dismutase cDNA tended to have reduced injury from water-deficit stress as determined by chlorophyll fluorescence, electrolyte leakage, and regrowth from crowns. A 3-year field trial indicated that yield and survival of transgenic plants were significantly improved, supporting the hypothesis that tolerance of oxidative stress is important in adaptation to field environments. 相似文献
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The trait for somatic embryogenesis is being introduced sexually into alfalfa (Medicago sativa) breeding populations to facilitate genetic transformation of this crop. Cocultivation experiments were conducted with an agronomically-improved embryogenic clone from one such population as well as with two other embryogenic clones, one of which was the source of the embryogenic trait in the breeding populations. Transgenic plants were produced from the agronomically-improved clone whereas none were produced from the other two clones. Among the 16 transgenic plants analyzed there was a range in both copy number and number of integration sites for the NPT-II gene; those plants regenerated after a prolonged selection phase in vitro generally had the highest numbers in both respects. There was no evidence of sectoral chimerism of the transgene in a subsample of transgenic plants analyzed by PCR. 相似文献
7.
Approaches to breeding for salinity tolerance - a case study on Porteresia coarctata 总被引:2,自引:0,他引:2
R LATHA C SRINIVAS RAO H M SR SUBRAMANIAM P EGANATHAN M S SWAMINATHAN 《The Annals of applied biology》2004,144(2):177-184
Cereals are the world's major source of food for human nutrition. Among these, rice (Oryza sativa) is the most prominent and represents the staple diet for more than two-fifths (2.4 billion) of the world's population, making it the most important food crop of the developing world (Anon., 2000a). Rice production in vast stretches of coastal areas is hampered due to high soil salinity. This is because rice is a glycophyte and it does not grow well under saline conditions. In order to increase rice production in these areas there is a need to develop rice varieties suited to saline environments. Research has shown that Porteresia coarctata, a highly salt tolerant wild relative of rice growing in estuarine soils, is an important material for transferring salt tolerant characteristics to rice. It is quite possible that Porteresia may be used as a parent for evolving better and truly salt resistant varieties. The inadequate results and the difficulties associated with conventional breeding techniques necessitate the use of the tools of crop biotechnology in unravelling some of the characteristics of Porteresia that have been highlighted in this report. In view of the limited resources available for increasing salinity tolerance to the breeders to wild rice germplasm, Porteresia is undoubtedly one of the key source species for elevating salinity tolerance in cultivated rice. 相似文献
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The effects of acute ethanol feeding and of chronic benfluorex administration on the activities of some enzymes of glycerolipid synthesis in rat liver and adipose tissue. 下载免费PDF全文
P H Pritchard M Bowley S L Burditt J Cooling H P Glenny N Lawson R G Sturton D N Brindley 《The Biochemical journal》1977,166(3):639-642
Activation of adenylate cyclase in isolated rat liver plasma membranes by cholera toxin was demonstrated. The activation requires the presence of NAD+ and ATP and is irreversible. 相似文献
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The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献