Imaging of trace metal distribution in the cadmium ( Cd) hyperaccumulator Indian mustard by laser ablation inductively coupled plasma-mass spectrometry ( LA-ICP-MS ) was typically performed using spatial resolutions of 25 μm. Indian Mustard was submitted to 50 mol/L Cd for 14 days exposure and analysed using Nd:YAG laser (213 nm) . Intensities of 13 C, 34 S, 39 K, 44 Ca, 66 Zn, 111 Cd, 65 Cu and 31 P were measured by ICP-MS to study elemental distribution. Preferential Cd accumulation in vascular bundles was observed in stem tissue, whereas Cd was mainly localized to the mesophyll and vascular cells. The high relationship between Ca and Cd distribution indicated that the two elements had a very similar pathway. In vivo analytical method developed in this work was useful to study spatial element distribution across stem samples and had great potential for applications in other areas of plant pathology research.

Objective:To explore the effect of intratracheal transplantation human umbilical cord blood mesenchymal stem cells on pulmonary interstitial fibrosis by bleomycin in mice,compare the treatment in pulmonary fibrosis of intratracheal transplantation with tail vain injection human umbilical cord blood mesenchymal stem cells.Methods:The second generation of HUCBMSCs were cultured to the fourth generation.Sixty specific pathogen free male Kunming mice were randomly divided into 4 groups:negative control group ( Cont group) ,bleomycin group( BLM group) ,HUCBMSCs transplantation groupⅠ( MⅠgroup) and HUCBMSCs transplantation groupⅡ(MⅡ group),each group 15 mice.Pulmonary fibrosis models were induced by bleomycin via intratracheal perfusion in the latter three groups.Twenty four hours after model establishment,5-bromo-2-deoxyuridine( Brdu) marked HUCBMSCs were poured in trachea in MⅠgroup ,the same were injected into tail vein in MⅡ group.At the 7th,14th,28th day,5 mice in each group were executed re-spectively.The morphological changes of the lung tissues were observed by HE staining and Masson staining.The localization and distribution of human umbilical cord blood mesenchymal stem cells were determined by the method of immunohistochemistry.The hydroxyproline contents were measured by alkali hydrolysis assay.The protein levels of transforming growth factor β-1 ( TGF-β1 ) and smooth muscle alpha-actin(α-SMA) were detected by Western blot.Results:In the two mesenchymal stem cell transplantation groups, there were Brdu marked cells at the 7th,14th,28th days in lung tissue.The alveolitis and fibrosis in lung of the two mesenchymal stem cell transplantation groups were milder than which of the the bleomycin group(P<0.05).Hydroxyproline levels in the bleomycin groups at 3 time points showed a gradually rising trend,the highest level was at 28th day( P<0.01).The protein levels of TGF-β1 andα-SMA in the lung tissues ranked as follows:BLM group>MⅠ,MⅡgroup>Cont group(P<0.05),the difference between MⅠgroup and MⅡgroup was not statistically significant(P>0.05).Conclusion:The colonization of human umbilical cord blood mesenchymal stem cells can be seen in the damaged tissue via intratracheal transplantation which can alleviate pulmonary fibrosis in mice caused by bleomycin.

Reduced sulfur compounds ( RSCs) are one of the main pollutant species in the atmosphere, so it is of great significance to develop a rapid and on-line approaches for their detection. In this study, a portable time-of-flight mass spectrometer ( TOF-MS) with magnetic field enhanced photoelectron ionization source was designed to detect RSCs. The photoelectron ionization source was induced from vacuum ultraviolet photons which generated from vacuum ultraviolet (VUV) lamp with energy of 10. 6 eV. The energy of photoelectrons was controlled by adjusting the extraction voltage to produce the photoelectron ionization, and an annular magnet was used in the ionization region to improve the ionization efficiency of photoelectrons. From the simulation result by SIMION software, it was found that the introduction of magnet field made the motion trajectroies of electrons in the helical motion increase and the convergence of electron at the ionization source was achieved. Experimental results showed that after introducing the magnet filed, the sensitivity of H2 S, SO2 and CS2 was improved by a factor of 5. 3, 9. 4 and 6. 9, respectively. With a detection time of 50 s, the limits of detection for H2S, SO2 and CS2 were 0. 14, 0. 52 and 0. 31 mg/m3(S/N=3), respectively. It could be concluded that the portable TOF-MS with magnetic field enhanced photoelectron ionization source has great potential to be applied for on-line monitoring of volatile sulfides at the emission source.

Escherichia coli is a highly adaptable opportunistic pathogen bacterium that can form biofilms on the surface of implants and generates persistent cells,leading to life-threatening infections that are difficult to treat with antibiotics alone.Therefore,there is a need for an effective E.coli biofilm inhibitor to combat this public health threat.Indole is a novel quorum-sensing signaling molecule of E.coli discovered in recent years,which is of great significance in regulating bacterial growth and biofilm formation,and is a potential target for future research on new anti-biofilm preparations.This article reviews the research progress on the formation of Escherichia coli biofilms,the microbial metabolism of indole and its regulation of Escherichia coli biofilm formation,in order to provide information for clinical treatment and drug development.

[摘 要] 目的：探讨橙花叔醇通过Wnt-β-catenin通路抑制黑色素瘤A-375和WM-115细胞恶性生物学行为的分子机制。方法: 体外培养黑色素瘤细胞A-375和WM-115，用不同浓度的橙花叔醇处理，采用SRB法和克隆形成实验、FCM术、Transwell实验和细胞划痕实验、DCFH-DA染色法、qPCR和WB法分别检测橙花叔醇对A-375和WM-115细胞的增殖能力、细胞周期和凋亡、迁移能力、活性氧（ROS）水平和Wnt-β-catenin通路及其下游相关基因和相关蛋白表达的影响。利用ULCAN和GEPIA2数据库分析黑色素瘤中Wnt-β-catenin通路的激活与患者预后的关系。结果：与对照组比较，橙花叔醇处理组A-375和WM-115细胞的增殖能力受明显抑制（均P<0.01）、细胞周期阻滞于G2/M期（P<0.05或P<0.01）、细胞凋亡率增加（均P<0.01）、迁移能力降低（P<0.05或P<0.01）、ROS水平升高（均P<0.01）、Wnt-β-catenin通路被抑制而其下游基因和蛋白表达明显上调（均P<0.01）。数据库数据分析显示，WNT1基因高表达患者OS低于低表达患者（P<0.01）。结论：橙花叔醇通过上调A-375和WM-115细胞中ROS水平影响Wnt-β-catenin通路，从而抑制其恶性生物学行为；Wnt-β-catenin通路可能是黑色素瘤治疗的潜在靶点。