1.
Reliable reference genes for normalization of gene expression data in tea plants (Camellia sinensis) exposed to metal stresses.
Wang, ML, Li, QH, Xin, HH, Chen, X, Zhu, XJ, Li, XH
PloS one. 2017;(4):e0175863
Abstract
Tea plants [Camellia sinensis (L.) O. Kuntze] are an important leaf-type crop that are widely used for the production of non-alcoholic beverages in the world. Exposure to excessive amounts of heavy metals adversely affects the quality and yield of tea leaves. To analyze the molecular responses of tea plants to heavy metals, a reliable quantification of gene expression is important and of major importance herein is the normalization of the measured expression levels for the target genes. Ideally, stably expressed reference genes should be evaluated in all experimental systems. In this study, 12 candidate reference genes (i.e., 18S rRNA, Actin, CYP, EF-1α, eIF-4α, GAPDH, MON1, PP2AA3, TBP, TIP41, TUA, and UBC) were cloned from tea plants, and the stability of their expression was examined systematically in 60 samples exposed to diverse heavy metals (i.e., manganese, aluminum, copper, iron, and zinc). Three Excel-based algorithms (geNorm, NormFinder, and BestKeeper) were used to evaluate the expression stability of these genes. PP2AA3 and 18S rRNA were the most stably expressed genes, even though their expression profiles exhibited some variability. Moreover, commonly used reference genes (i.e., GAPDH and TBP) were the least appropriate reference genes for most samples. To further validate the suitability of the analyzed reference genes, the expression level of a phytochelatin synthase gene (i.e., CsPCS1) was determined using the putative reference genes for data normalizations. Our results may be beneficial for future studies involving the quantification of relative gene expression levels in tea plants.
2.
Analysis of four toxic metals in a single rice seed by matrix solid phase dispersion -inductively coupled plasma mass spectrometry.
He, X, Chen, L, Chen, X, Yu, H, Peng, L, Han, B
Scientific reports. 2016;:38472
Abstract
Toxic metals in rice pose great risks to human health. Metal bioaccumulation in rice grains is a criterion of breeding. Rice breeding requires a sensitive method to determine metal content in single rice grains to assist the variety selection. In the present study, four toxic metals of arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) in a single rice grain were determined by a simple and rapid method. The developed method is based on matrix solid phase dispersion using multi-wall carbon nanotubes (MWCNTs) as dispersing agent and analyzed by inductively coupled plasma mass spectrometry. The experimental parameters were systematically investigated. The limits of detection (LOD) were 5.0, 0.6, 10 and 2.1 ng g-1 for As, Cd, Cr, and Pb, respectively, with relative standard deviations (n = 6) of <7.7%, demonstrating the good sensitivity and precision of the method. The results of 30 real world rice samples analyzed by this method agreed well with those obtained by the standard microwave digestion. The amount of sample required was reduced approximately 100 fold in comparison with the microwave digestion. The method has a high application potential for other sample matrices and elements with high sensitivity and sample throughput.
3.
Development and application of metal materials in terms of vascular stents.
Wu, T, Chen, X, Fan, D, Pang, X
Bio-medical materials and engineering. 2015;(4):435-41
Abstract
BACKGROUND With life pace accelerated, poor diet habits developed, psychological burden enhanced and many other factors, the incidence of coronary heart disease, atherosclerosis and other cardiovascular cerebrovascular diseases has been increased year by year, which are serious threat to human health. OBJECTIVE Provide relational references for the similar researchers after metal stent materials were reviewed and prospected. METHODS This paper reviews the development and application of metal materials in terms of vascular stents, focusing on the advantages and disadvantages of 316L stainless steel, nitinol super-elastic alloys, cobalt-based alloys (Co-Cr-Ni-Mo-Mn), magnesium-based alloy, iron-based alloys and tantalum metal stents as well as in clinical practice research and application. RESULTS Recognize the advantages and disadvantages of different metal stent materials as well as in clinical practice research and application. CONCLUSIONS Although metal stents have been widely used in clinical practice, there are still many problems to be solved, especially to improve mechanical properties and biological activity. Strong immune rejection is also a problem. Therefore, it will be a significant direction for future material research to treat surface modification, further improve the biocompatibility, reduce the thrombosis and completely eliminate the rejection and vascular restenosis. In addition, the stent materials should be developed toward controllable degradation and special features in the future.