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Localization polymorphism of EBV DNA genomes in the chromosomes of Burkitt lymphoma cell lines 总被引:1,自引:0,他引:1
The localization of Epstein-Barr virus (EBV) genomes in nuclei of the human lymphoblastoïd cell lines Raji, Jijoye, P3HR-1, Daudi and Ramos was investigated by in situ hybridization with biotinylated EBV DNA probes. We found that all sites of hybridization were associated with the chromosomes. Only some of these sites were present on both chromatids and these had a non-random distribution; these sites could represent EBV sequences integrated at specific points on the chromosomes. The total mean site number corresponded with the number of viral DNA copies estimated in the different cell lines by other techniques, but the copy number was highly variable from cell to cell in a given line. 相似文献
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Chong‐Yi Ma Wei Chen Lu Sun Wei Liu Dong‐Yang Zhang Bi‐Cheng Fu Kai‐Yu Liu Zhi‐Bo Jia Bao‐Dong Xie Shu‐Lin Jiang Ren‐Ke Li Hai Tian 《Journal of cellular and molecular medicine》2014,18(11):2298-2310
Sirtuin3 (SIRT3) is an important member of the sirtuin family of protein deacetylases that is localized to mitochondria and linked to lifespan extension in organisms ranging from yeast to humans. As aged cells have less regenerative capacity and are more susceptible to oxidative stress, we investigated the effect of ageing on SIRT3 levels and its correlation with antioxidant enzyme activities. Here, we show that severe oxidative stress reduces SIRT3 levels in young human mesenchymal stromal/stem cells (hMSCs). Overexpression of SIRT3 improved hMSCs resistance to the detrimental effects of oxidative stress. By activating manganese superoxide dismutase (MnSOD) and catalase (CAT), SIRT3 protects hMSCs from apoptosis under stress. SIRT3 expression, levels of MnSOD and CAT, as well as cell survival showed little difference in old versus young hMSCs under normal growth conditions, whereas older cells had a significantly reduced capacity to withstand oxidative stress compared to their younger counterparts. Expression of the short 28 kD SIRT3 isoform was higher, while the long 44 kD isoform expression was lower in young myocardial tissues compared with older ones. These results suggest that the active short isoform of SIRT3 protects hMSCs from oxidative injury by increasing the expression and activity of antioxidant enzymes. The expression of this short isoform decreases in cardiac tissue during ageing, leading to a reduced capacity for the heart to withstand oxidative stress. 相似文献
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Potential applications of cryogenic technologies to plant genetic improvement and pathogen eradication 总被引:1,自引:0,他引:1
Biao Wang Ren-Rui Wang Zhen-Hua Cui Wen-Lu Bi Jing-Wei Li Bai-Quan Li Elif Aylin Ozudogru Gayle M. Volk Qiao-Chun Wang 《Biotechnology advances》2014
Rapid increases in human populations provide a great challenge to ensure that adequate quantities of food are available. Sustainable development of agricultural production by breeding more productive cultivars and by increasing the productive potential of existing cultivars can help meet this demand. The present paper provides information on the potential uses of cryogenic techniques in ensuring food security, including: (1) long-term conservation of a diverse germplasm and successful establishment of cryo-banks; (2) maintenance of the regenerative ability of embryogenic tissues that are frequently the target for genetic transformation; (3) enhancement of genetic transformation and plant regeneration of transformed cells, and safe, long-term conservation for transgenic materials; (4) production and maintenance of viable protoplasts for transformation and somatic hybridization; and (5) efficient production of pathogen-free plants. These roles demonstrate that cryogenic technologies offer opportunities to ensure food security. 相似文献
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Effect of cotton nitrogen fertilization on Bemisia argentifolii populations and honeydew production 总被引:2,自引:0,他引:2
J.L. Bi G.R. Ballmer D.L. Hendrix T.J. Henneberry N.C. Toscano 《Entomologia Experimentalis et Applicata》2001,99(1):25-36
The impact of nitrogen fertilization on cotton plants, Gossypium hirsutum L., silverleaf whitefly, Bemisia argentifolii Bellows & Perring, population dynamics and honeydew production were investigated in the field at Riverside, California, USA. Treatments were soil applications of 0, 112, 168 and 224 kg nitrogen per hectare, and a soil application of 112 kg of nitrogen plus a foliar application of 17 kg nitrogen per hectare. Increased numbers of both adult and immature whiteflies occurred during population peaks with increasing amounts of applied nitrogen. Higher numbers of whiteflies resulted in increased levels of honeydew. Increasing plant nitrogen also enhanced cotton foliar photosynthetic rates and stomatal conductance, and altered concentrations of glucose, fructose and sucrose in cotton petioles. However, at our treatment levels nitrogen had no effect on seedcotton yield. Petiole glucose levels were significantly correlated with numbers of whitefly adults on leaves during their peak populations. Significant correlations between whitefly numbers and other cotton physiological parameters occurred on only a few sampling dates. 相似文献