Browsing by Author "Wang, Mei"
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Item Evolutionary divergence of function and expression of laccase genes in plants(Indian Academy of Sciences, 2020-03) Liu, Mingyue; Dong, Hui; Wang, Mei; Liu, QingpoLaccases (LACs) are versatile enzymes that catalyze oxidation of a wide range of substrates, thereby functioning in regulation of plant developmental processes and stress responses. However, with a few exceptions, the function of most LACs remains unclear in plants. In this study, we newly identified 4, 12, 22, 26, 27, 28 and 49 LAC genes for Physcomitrella patens, Amborella trichopoda, Zea mays, Ricinus communis, Vitis vinifera, Triticum aestivum and Glycine max, on the basis of exhaustive homologous sequence searches. In these plants, LACs differ greatly in sequence length and physical properties, such as molecular weight and theoretical isoelectric point (pI), but majority of them contain a signal peptide at their N-terminus. The originality of LACs could be traced back to as early as the emergence of moss. Plant LACs are clearly divided into seven distinct classes, where six ancient LACs should be present prior to the divergence of gymnosperms and angiosperms. Functional divergence analysis reveal that functional differentiation should occur among different groups of LACs because of altered selective constraints working on some critical amino acid sites (CAASs) within conserved laccase domains during evolution. Soybean and maize LACs have significantly different exon frequency (6.08 vs 4.82), and they are unevenly distributed and tend to form gene clusters on some chromosomes. Further analysis shows that the expansion of LAC gene family would be due to extensive tandem and chromosomal segmental duplications in the two plant species. Interestingly, *81.6% and 36.4% of soybean and maize LACs are potential targets of miRNAs, such as miR397a/b, miR408d, or miR528a/b etc. Both soybean and maize LACs are tissuespecifically and developmental-specifically expressed, and are in response to different external abiotic and biotic stressors. These results suggest a diversity of functions of plant LAC genes, which will broaden our understanding and lay solid foundation for further investigating their biological functions in plants.Item Fluctuation of circulating tumor cells in patients with lung cancer by real-time fluorescent quantitative-PCR approach before and after radiotherapy.(2005-10-14) Ge, Mingjian; Shi, De; Wu, Qingchen; Wang, Mei; Li, LiangbinBACKGROUND AND AIMS: The failure to reduce the mortality of patients with solid tumours is mainly a result of the early dissemination of cancer cells to secondary site, which is usually missed by conventional diagnostic procedures used for tumour staging. The possibility to use easily accessible body fluids as a source for circulating tumour cells (CTCs) detection enables longitudinal observations of the disease. In the study, we evaluated the CTCs in lung cancer following locoregional radiation therapy. METHODS: Samples of 5 ml peripheral blood was taken from each lung cancer patients (n=15) both before and after the radiotherapy course. Meanwhile tumour size was determined by chest X-ray or computed tomography. Using cytokeratin 19(CK19) as marker, the blood samples were subjected to real time RT-PCR assay. All patients with lung cancer were treated with primary definitive and mediastinal radiotherapy. RESULTS: Compare to that of pre-treatment, the value of CK19 mRNA in peripheral blood after therapy decreased dramatically (5.0932+/-1.0628 vs. 4.2493+/-0.8323, t=3.192, P=0.007). The change of CK19 mRNA level before and after radiotherapy was closely related to the type (NSCLC vs. SCLC, 0.5389+/-0.9030 vs. 1.6826+/-0.9467, t=2.1465, P=0.051). Meanwhile, there appeared to be a close link between the grade (Well/Mod vs. Poor) and the change of CK19 mRNA (0.5024 vs. 1.5271, t=2.017, P=0.065). The change of CK19 mRNA level was related to variation of tumour burden during radiotherapy (r=0.0575, P=0.025). Of the 15 cases studied, 12 cases were positive before radiotherapy (12/15, 80%). The positive rate was 53% (8/15) after radiotherapy, meaning that four patients converted into negative after radiotherapy. CONCLUSIONS: The disseminated circulating cancer cells can be affected by radiotherapy; meanwhile further more systemic adjuvant treatment should be conducted. Due to concordance between molecular response and radiological remission, assessment of the therapeutic response might be possible by serial quantitative of CTCs.