Expression and functional characterization of platelet-derived growth factor receptor-like gene

AIM:To investigate the role of platelet-derived growth factor receptor-like gene(PDGFRL)in the anti-cancer therapy for colorectal cancers(CRC).METHODS:PDGFRL mRNA and protein levels were measured by reverse transcription-polymerase chain reaction(RT-PCR)and immunohistochemistry in CRC and colorectal normal tissues.PDGFRL prokaryotic expression vector was carried out in Escherichia coli(E.coli),and purified by immobilized metal affinity chromatography.The effect of PDGFRL protein on CRC HCT-116 cells was detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide(MTT),clone counting,cell cycle,and wound healing assay.RESULTS:Both RT-PCR and immunohistochemistry showed that the expression of PDGFRL in colorectal normal tissues was higher than in cancer tissues.Recombinant pET22b-PDGFRL prokaryotic expression vector was successfully expressed in E.coli,and the target protein was expressed in the form of inclusion bodies.After purification and refolding,recombinant human PDGFRL(rhPDGFRL)could efficiently inhibit the proliferation and invasion of CRC HCT-116 cells detected by MTT,clone counting and wound healing assay.Moreover,rhPDGFRL arrested HCT-116 cell cycling at the G0/G1 phase.CONCLUSION:PDGFRL is a potential gene for application in the anti-cancer therapy for CRC.

Fine-scale genetic structure of Eremosparton songoricum and implication for conservation

Eremosparton songoricum (Litv.) Vass. is a clonal shrub that reproduces both asexually by under-ground rhizomes and sexually by seeds. It is now a rare species with a narrow distribution in fragmented habitat patches in the Gurbantunggut Desert of Xinjiang, China. The objective of this study was to determine the spatial pattern or structure of genetic variation within population. The within-populations genetic structure of E. songoricum in a plot (10 m×10 m) was analyzed using inter simple sequence repeats (ISSR) markers. Correlograms of Moran’s I showed significant positive value was about 7 m, but changed into a negative correlation with the increase of distance, indicating strong genetic structure. The natural character of clonal reproduction, restricted seed and pollen dispersal were the main factors of influencing the spatial pattern. The knowledge of clonal structures within populations was crucial for understanding evolutionary processes and ecological adaptation. This study provided basic data for the conservation and management of E. songoricum, especially for sampling strategies for ex situ conservation.

Identification of genes upregulated by recombinant interferon-alpha in HepG2 cells by suppressive subtractive hybridization analysis

BACKGROUND: Interferon-alpha (IFN-alpha) is an important cytokine with multiple functions, but the target genes transactivated by IFN-alpha remain largely unknown. A study of such genes will help to understand the mechanism of function of IFN-alpha. To isolate the gene transcripts specifically upregulated by IFN-alpha in HepG2 cells, we conducted suppressive subtractive hybridization (SSH) analysis. METHODS: SSH was used to analyze the target genes transactivated by recombinant IFN-alpha protein, and a subtractive cDNA library was constructed from HepG2 cells treated with recombinant IFN-alpha (rIFN-alpha, 2000 IU/ml) for 16 hours as tester, and cells not treated with rIFN-alpha as driver. The SSH PCR products from the library were cloned into pGEM-T easy vector and with BLASTX, the positive clones were randomly selected, sequenced and compared to the database in GenBank of the 35 differentially expressed gene fragments from the library, 6 clones showed significant homology to other known proteins. RESULTS: The subtractive cDNA library of genes upregulated by IFN-alpha was constructed successfully, rIFN-alpha upregulated the expression of the RAN binding protein 5 (RANBP5), NADH dehydrogenase, exosome component 3 (EXOSC3), zinc finger RNA binding protein, Dickkopf homolog 1 (DKK1) and acetyl-coenzyme A acetyltransferase 2 (ACAT2). CONCLUSIONS: These results suggest that rIFN-alpha can upregulate the expression of important genes to exert its functions, and provide new clues for discovering the molecular mechanisms of action of IFN-alpha.

糖尿病视网膜病变患病率的流行病学调查：在中国6省13473名糖尿病患者中的横断面研究

目的本研究旨在探究中国糖尿病患者中糖尿病视网膜病变（DR）和视力威胁性糖尿病视网膜病变（STDR）的患病率和严重程度。研究设计、设置与参与者本研究为横断面流行病学调查，研究对象为中国内地地区的糖尿病患者（N=13473）。研究对象为被内科医师诊断为糖尿病，并转诊到筛查门诊的糖尿病患者（其中住院患者占1／3，城市居民占1／3，农村居民占1／3）。研究对象的每只眼睛应用彩色、免散瞳和非立体眼底照相机拍摄2张眼底照片，并根据英国DR分级指南进行分级。主要结果和测量指标DR与STDR的患病率和严重程度。结果在参与本研究的13473例糖尿病患者中，共发现4591例DR和1769例STDR患者，DR的总体患病率为34．08％[95％可信区间（凹）33．28％～34．88％]，其中STDR的总体患病率为13．13％（95％C112．56％～13．70％）。在所有研究对象中，12780例参与了眼底照片分级（94．86％）。年龄大于65岁的研究对象患DR或STDR的可能性较低（P〈0．001）。性别对是否患病没有显著影响（P〉0．05）。STDR患者与非STDR患者相比，视力损伤更为严重（P〈0．001）。中国北方DR和STDR的患病率高于南方（P〈0．001）。DR的患病率与糖尿病患病时间f比值比（鲫）2．63；95％C12．42～2．86；P〈0．001]以及糖尿病发病年龄（OR 0．38；95％CI为0．35～0．41；P〈0．001）密切相关。结论DR和STDR在中国内地地区的患病率偏高，并且不同地区患病率存在差异。在DR中，非增殖性DR更常见，但STDR更需要及时的诊断和治疗，特别是在经济欠发达地区。本研究强调了中国内地地区DR筛查和治疗的重要性。

Selective Adsorption of Co（II） by Mesoporous Silica SBA-15-Supported Surface Ion Imprinted Polymer： Kinetics, Isotherms, and Thermodynamics Studies

A novel surface ion implinted adsorbent [Co（II）-IIP] using polyethyleneimine （PEI） as function monomer and ordered mesoporous silica SBA-15 as support matrix was prepared for Co（II） analysis with high selectivity. The prepared polymer was characterized by Fourier transmission infrared spectrometry, scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption isotherm. Bath experiments of Co（II） adsorption onto Co（II）-IIP were performed under the optimum conditions. The experimental data were analyzed by pseudo-first-order and pseudo-second-order kinetic models. It was found that the pseudo-second-order model best correlated the kinetic data. The intraparticle diffusion and liquid film diffusion were applied to discuss the adsorption mechanism. The results showed that Co（II） adsorption onto IIP was controlled by the intraparticle diffusion mechanism, along with a considerable film diffusion contribution. Langmuir, Freundlich and Dubinin-Radushkevich adsorption models were applied to determine the isotherm parameters. Langmuir model fitted the experiment data well and the maximum calculated capacity of Co（II） reached 39.26 mg/g under room temperature. The thermodynamic data were indicative of the spontaneousness of the endothermic sorption process of Co（II） onto Co（II）-IIP. Co（II）-IIP showed high affinity and selectivity for template ion compared with non imprinted polymer （NIP）.

Dual-Source Nuclear Monomers of UV-B Light Receptor Direct Photomorphogenesis in Arabidopsis

Dear Editor,The ultraviolet （UV）-B wavelength （280-315 nm） is an indispensable component of the sunlight that reaches the earth＇s surface. Long-wavelength and Iow-fluence UV-B specifically induces plant photomorphogenesis, which is characterized by inhibition of hypo- cotyl elongation, promotion of anthocyanin accumulation, and eventually tolerance against UV-B stress （Jenkins, 2009）.

DFT Studies on Detonation Properties, Pyrolysis Mechanism, and Stability of the Nitro and Hydroxyl Derivatives of Benzene

Ninety-one nitro and hydroxyl derivatives of benzene were studied at the B3LYP/6-31G＊ level of density functional theory. Detonation properties were calculated using the Kamlet-Jacobs equation. Three candidates （pentanitrophenol, pentanitrobenzene, and hexanitrobenzene） were recommended as potential high energy density compounds for their perfect detonation performances and reasonable stability. The pyrolysis mechanism was studied by analyzing the bond dissociation energy （BDE） and the activation energy （Ea） of hydrogen transfer （H--T） reaction for those with adjacent nitro and hydroxyl groups. The results show that Ea is much lower than BDEs of all bonds, so when there are adjacent nitro and hydroxyl groups in a molecule, the stability of the compound will decrease and the pyrolysis will be initiated by the H--T process. Otherwise, the pyrolysis will start from the breaking of the weakest C--NO2 bond, and only under such condition, the Mulliken population or BDE of the C--NO2 bond can be used to assess the relative stability of the compound.