Activation of Notch-1 enhances epithelial-mesenchymal transition in gefitinib-acquired resistant lung cancer cells

Despite an initial response to EGFR tyrosine kinase inhibitors (EGFR-TKI) in EGFR mutant lung cancer, most patients eventually become resistant and result in treatment failure. Recent studies have shown that epithelial to mesenchymal transition (EMT) is associated with drug resistance and cancer cell metastasis. Strong multiple gene signature data indicate that EMT acts as a determinant of insensitivity to EGFR-TKI. However, the exact mechanism for the acquisition of the EMT phenotype in EGFR-TKI resistant lung cancer cells remains unclear. In the present study, we showed that the expression of Notch-1 was highly upregulated in gefitinib-resistant PC9/AB2 lung cancer cells. Notch-1 receptor intracellular domain (N1IC), the activated form of the Notch-1 receptor, promoted the EMT phenotype in PC9 cells. Silencing of Notch-1 using siRNA reversed the EMT phenotype and restored sensitivity to gefitinib in PC9/AB2 cells. Moreover, Notch-1 reduction was also involved in inhibition of anoikis as well as colony-formation activity of PC9/AB2 cells. Taken together, these results provide strong molecular evidence that gefitinib-acquired resistance in lung cancer cells undergoing EMT occurs through activation of Notch-1 signaling. Thus, inhibition of Notch-1 can be a novel strategy for the reversal of the EMT phenotype thereby potentially increasing therapeutic drug sensitivity to lung cancer cells.     

Genetic Variation Analysis of Mugil cephalus in China Sea Based on Mitochondrial COI Gene Sequences

In this study, genetic diversity and population genetic structure of flathead grey mullet, Mugil cephalus, among four China Sea populations were investigated by COI sequences. All the populations studied had high values of haplotype and nucleotide diversity, except for the Yellow Sea population. In the phylogenetic tree, these haplotypes clustered in two groups, one for the populations from the Bohai and East China seas, and the other from the Yellow and South China seas. Analysis of molecular variance indicated that the northern populations (Bohai and East China) had lower genetic divergence (0.0725, P > 0.05) than that of the southern population (South China) (0.4530-0.6827, P < 0.001), suggesting that two distinct genetic groups exist in Chinese waters. Tests of neutral evolution and mismatch distribution indicated that no historical demographic expansion occurred in these populations. The results provide new information for genetic assessment, fishery management, and conservation of this species.     

东亚大都市学生头型的比较研究

为了研讨居住区域的气候条件和社会经济环境对头型的影响,采用国际通用的人体测量法,调查测量了东亚三个国家四个集团３４７２名６－１７岁学生的头长和头宽,经统计学处理求得其平均值、头指数,回归方程,并作性差和地区差检验,其结果表明：中国大连学生为特圆头型,菲律宾马尼拉学生为圆头型,地理位置在大连和马尼拉之间的日本东京的学生的头型也位于二者之间,生活富裕集团的头长和头宽明显大于生活贫穷集团的学生,但头型二     

Broadening the versatility of lentiviral vectors as a tool in nucleic acid research via genetic code expansion

With the aim of broadening the versatility of lentiviral vectors as a tool in nucleic acid research, we expanded the genetic code in the propagation of lentiviral vectors for site-specific incorporation of chemical moieties with unique properties. Through systematic exploration of the structure–function relationship of lentiviral VSVg envelope by site-specific mutagenesis and incorporation of residues displaying azide- and diazirine-moieties, the modifiable sites on the vector surface were identified, with most at the PH domain that neither affects the expression of envelope protein nor propagation or infectivity of the progeny virus. Furthermore, via the incorporation of such chemical moieties, a variety of fluorescence probes, ligands, PEG and other functional molecules are conjugated, orthogonally and stoichiometrically, to the lentiviral vector. Using this methodology, a facile platform is established that is useful for tracking virus movement, targeting gene delivery and detecting virus–host interactions. This study may provide a new direction for rational design of lentiviral vectors, with significant impact on both basic research and therapeutic applications.     

Enhanced chemiluminescence enzyme‐linked immunoassay for the determination of DNA methyltransferase 1 in human serum

The occurrence of many diseases is closely related to the high expression of DNA methyltransferase 1 (DNMT1). However, most studies are focused on the detection of DNMT1 activity, a few are concerned with the detection of DNMT1 content. In this study, we developed a simple and highly sensitive chemiluminescence (CL) assay for the detection of DNMT1 content. In this method, anti‐DNMT1 monoclonal antibody was coated on a polystyrene microplate to capture DNMT1. Then anti‐DNMT1 polyclonal antibody and goat anti‐rabbit immunoglobulin G with horseradish peroxidase (IgG‐HRP) were respectively added to combine with captured DNMT1 to form a sandwich structure. Finally, the HRP could catalyze CL substrate and achieve CL signal response. Based on this novel sensitive strategy, the recovery percents were in the ranges from 71.5% to 91.0%. The precision of intra‐assays and inter‐assays were 5.45%–11.29% and 7.03%–11.25%, respectively. The method was successfully applied for the determination of DNMT1 in human serum. The detection results of serum samples showed that the proposed assay had a high correlation with enzyme‐linked immunosorbent assay (ELISA) kit. Compared with the ELISA kit (limit of detection = 0.1 ng/mL), the method has a lower limit of detection of 0.042 ng/mL. Therefore, our method has the potential for the detection of DNMT1 content in clinical diagnosis.     

Evolutionary dynamics of ecological niche in three Rhinogobio fishes from the upper Yangtze River inferred from morphological traits

In the past decades, it has been debated whether ecological niche should be conserved among closely related species (phylogenetic niche conservatism, PNC) or largely divergent (traditional ecological niche theory and ecological speciation) and whether niche specialist and generalist might remain in equilibrium or niche generalist could not appear. In this study, we employed morphological traits to describe ecological niche and test whether different niche dimensions exhibit disparate evolutionary patterns. We conducted our analysis on three Rhinogobio fish species (R. typus, R. cylindricus, and R. ventralis) from the upper Yangtze River, China. Among the 32 measured morphological traits except body length, PCA extracted the first four principal components with their loading scores >1.000. To find the PNC among species, Mantel tests were conducted with the Euclidean distances calculated from the four principal components (representing different niche dimensions) against the pairwise distances calculated from mitochondrial cytochrome b sequence variations. The results showed that the second and the third niche dimension, both related to swimming ability and behavior, exhibited phylogenetic conservatism. Further comparison on niche breadth among these three species revealed that the fourth dimension of R. typus showed the greatest width, indicating that this dimension exhibited niche generalism. In conclusion, our results suggested that different niche dimensions could show different evolutionary dynamic patterns: they may exhibit PNC or not, and some dimensions may evolve generalism.     

芒草种植对土壤细菌群落结构和功能的影响

芒草作为第二代能源植物的代表,其生长过程中根际土壤细菌群落的结构与功能尚不清楚.本研究以种植5年的芒草(湘杂芒1号)为研究对象,选取裸地作为对照,采用16S rRNA基因Miseq测序技术研究其细菌群落组成,同时采用PICRUSt功能预测分析其功能.结果表明: 芒草根际细菌由变形菌门、酸杆菌门、放线菌门、绿弯菌门、拟杆菌门和芽单胞菌门等23个门、231个属的细菌组成,表现出群落组成的丰富性.细菌群落分析表明,种植湘杂芒1号改变了根际细菌群落结构,其细菌群落多样性低于裸地对照.PICRUSt功能预测分析表明,湘杂芒1号根际细菌主要涉及氨基酸运输和代谢、细胞壁/细胞膜/膜结构的生物合成、信号转导机制等24个基因功能家族,表现出功能上的丰富性,并有22个基因功能家族预测基因相对丰度高于裸地,表明种植湘杂芒1号提高了根际细菌功能.对氮、磷循环相关基因进行分析表明,种植湘杂芒1号改变了土壤氮、磷代谢能力.