Structure of plant photosystem I−light harvesting complex I supercomplex at 2.4 Å resolution

Photosystem I (PSI) is one of the two photosystems in photosynthesis, and performs a series of electron transfer reactions leading to the reduction of ferredoxin. In higher plants, PSI is surrounded by four light-harvesting complex I (LHCI) subunits, which harvest and transfer energy efficiently to the PSI core. The crystal structure of PSI-LHCI supercomplex has been analyzed up to 2.6 Å resolution, providing much information on the arrangement of proteins and cofactors in this complicated supercomplex. Here we have optimized crystallization conditions, and analyzed the crystal structure of PSI-LHCI at 2.4 Å resolution. Our structure showed some shift of the LHCI, especially the Lhca4 subunit, away from the PSI core, suggesting the indirect connection and inefficiency of energy transfer from this Lhca subunit to the PSI core. We identified five new lipids in the structure, most of them are located in the gap region between the Lhca subunits and the PSI core. These lipid molecules may play important roles in binding of the Lhca subunits to the core, as well as in the assembly of the supercomplex. The present results thus provide novel information for the elucidation of the mechanisms for the light-energy harvesting, transfer and assembly of this supercomplex.     

胸腹腔镜联合Ivor Lewis食管癌根治术对食管癌患者肺功能、红细胞免疫及应激反应的影响

目的:探讨胸腹腔镜联合Ivor Lewis食管癌根治术对食管癌患者红细胞免疫、肺功能及应激反应的影响。方法:选取2016年5月~2018年6月期间我院收治的食管癌患者150例。根据随机数字表法将患者分为A组(n=75)和B组(n=75),A组予以开胸Ivor Lewis食管癌根治术,B组予以胸腹腔镜联合Ivor Lewis食管癌根治术,比较两组围术期指标、肺功能、红细胞免疫、应激反应及并发症。结果:B组手术时间、住院时间短于A组,术中出血量少于A组(P<0.05);两组清扫淋巴结数目比较无差异(P>0.05)。两组术后1个月第1秒末用力呼气容积(FEV1)、用力呼吸肺活量(FVC)、FEV1/FVC均降低,但B组高于A组(P<0.05)。两组术后3d白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)均升高,但B组低于A组(P<0.05)。两组术后3d红细胞免疫复合物花环率(RBC-ICR)升高,但B组低于A组(P<0.05);红细胞C3b受体花环率(RBC-C3bRR)、肿瘤红细胞花环率(TRR)降低,但B组高于A组(P<0.05)。两组患者术后并发症发生率比较差异无统计学意义(P>0.05)。结论:胸腹腔镜联合Ivor Lewis食管癌根治术治疗食管癌患者,可有效改善围术期各项指标,减轻对机体肺功能、红细胞免疫及应激反应的影响,且不增加并发症发生率。     

三氟苯嘧啶不同种子处理方式对稻飞虱的控制效应

为探明三氟苯嘧啶不同种子处理方式对稻飞虱的田间防治效果、防治时长以及对稻田蜘蛛和水稻的安全性,为该药剂种子处理防治稻飞虱提供科学依据,本研究设置10％三氟苯嘧啶悬浮剂按不同浓度(0.375、0.75、1.125和1.5 g a.i./kg种子)对水稻种子分别以干种子拌种(干拌)、清水浸种后拌种(湿拌)和药剂浸种3种方式,清水处理作为空白对照.结果表明,3种处理方式下的水稻发芽率和出苗率均与空白对照间无显著差异,播种后100 d,各浓度对稻飞虱的防治效果均在90％以上;当药剂浓度相同时,干拌与湿拌防治时长要优于药剂浸种;不同浓度三氟苯嘧啶药剂处理在3种方式下稻田蜘蛛种群数量均略低于空白对照田蜘蛛数量.因此,水稻生产中使用三氟苯嘧啶0.375～1.5 g a.i./kg种子干拌或湿拌处理,可有效降低田间稻飞虱种群数量,对天敌蜘蛛影响较小,对水稻种子发芽、出苗安全,可在水稻生产中推广使用.     

联合TCGA和GEO数据库筛选乳腺癌易感基因

本研究是利用公共基因芯片数据库筛选乳腺癌的预后基因,预测和探索这些基因在乳腺癌进展中的可能机制和临床价值.首先,我们筛选了公共基因芯片数据库(gene expression omnibus,GEO)GSE22820和癌症基因组图谱(the cancer genome atlas,TCGA)乳腺癌数据库的重叠差异表达基因,联合R语言分析乳腺癌组织与癌旁正常组织差异表达的基因;其次,基于STRING数据库及Cytoscape软件构建蛋白质相互作用网络图,分析并识别了中枢基因和前3个模块;之后进行了更多的功能分析,包括基因本体(gene ontology,GO)和京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路分析以及基因集富集分析(gene set enrichment analysis,GSEA),以研究这些基因的作用以及潜在的潜在机制;最后进行了Kaplan-Meier分析和Cox比例风险分析,以阐明这些基因的诊断和预后效果.相关数据分析表明15个基因的表达水平与生存预后相关,高表达基因患者的总生存时间短于低表达患者(P＜0.05);Cox比例风险分析表明UBE2T、ER-CC6L和RAD51这3个基因是预后生存的独立因素(P＜0.05);GSEA分析表明在UBE2T、ERCC6L和RAD51基因中细胞周期、基础转录因子和卵母细胞减数分裂明显富集.最终,我们得出结论,这3种基因标志物的高表达是乳腺癌预后不良因素,可作为预测乳腺癌患者转移和预后的有效生物标志物.     

基于GEO数据库的肝癌相关基因的筛选及验证

肝细胞癌(hepatocellular carcinoma,HCC)是中国高发的恶性肿瘤之一,识别肝细胞癌发生发展相关基因,对于深入研究肝癌发病机制和开发诊疗靶点均具有重要意义.本研究利用GEO2R工具从基因表达汇编数据库(Gene Expression Omnibus Database,GEO)筛选5个数据集中共有的差异表达基因作为潜在的肝癌相关基因.利用Metascape网站,对差异表达基因进行功能富集及信号通路分析.结合GEPIA(Gene Expres-sion Profiling Interaction Analysis)网站筛选具有临床意义的基因.利用荧光定量PCR技术验证与肝癌预后相关的差异表达基因,候选肝癌相关基因,为后续的深入研究奠定扎实的基础.结果显示,从5个数据集中共发现94个共有的差异表达基因.文献检索后发现24个基因与肝癌发生发展的关系少见文献报道,属于肝癌中未知功能基因.利用GEPIA分析癌症基因组图谱(the cancer genome atlas,TCGA)中数据后发现,GINS1在肝癌组织中高表达,与肝癌患者生存期呈负相关;CFHR4和DNASE1L3在肝癌组织中显著低表达,与肝癌患者生存期呈正相关.荧光定量PCR技术证实GINS1在81.3％的肝癌组织中呈现高表达,CFHR4和DNAS-E1L3分别在71.9％和93.8％肝癌组织中低表达.因此,本研究发现GINS1、CFHR4和DNASE 1L3在肝癌组织中显著差异表达,与肝癌患者的预后密切相关,可能作为潜在的判断肝癌患者预后的分子标志物和研发肝癌治疗的潜在靶标.     

Longitudinal virological changes and underlying pathogenesis in hospitalized COVID-19 patients in Guangzhou,China

Science China Life Sciences - Prolonged viral RNA shedding and recurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in coronavirus disease 2019 (COVID-19) patients have been...     

Transmission of synovial sarcoma from a single multi-organ donor to three transplant recipients: case report

Quick and reliable testing of EGFR and KRAS is needed in non-small cell lung cancer (NSCLC) to ensure optimal decision-making for targeted therapy. The Idylla™ platform was designed for Formalin-Fixed Paraffin-Embedded (FFPE) tissue sections but recently several studies were published that evaluated its potential for cytological specimens. This study aimed to validate the Idylla™ platform for the detection of EGFR/KRAS mutations in cytological NSCLC samples prepared as cytoblocks using AGAR and paraffin embedding. The KRAS Idylla™ test were performed on 11 specimens with a known KRAS mutation. The EGFR Idylla™ test was performed on 18 specimens with a known primary EGFR mutation and 7 specimens with a primary EGFR-EGFR T790M resistance mutation combination. Concordant KRAS and primary EGFR mutations were detected for both KRAS and primary EGFR mutations. Samples with a total CQ value of < 26 could be considered negative. Samples with a total CQ value of > 26 could not be assessed (probability of false-negative). In specimens with a primary EGFR-EGFR T790M resistance mutation combination, 5/7 cases were not concordant. Our results confirm the conclusion of recent reports that the Idylla™EGFR assay is not suitable in a resistance to EGFR TKI setting, also not in our cytological NSCLC samples prepared as cytoblocks using AGAR and paraffin embedding. KRAS and primary EGFR mutations were detected using the Idylla™ assays in virtually all cytological NSCLC samples. This analysis was rapid and time-saving compared to other mutation detection assays and may be useful if the amount of material is insufficient to perform a full set of molecular tests.