Roles of a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism in ABA signal production in Arabidopsis

ABA, acting as a stress signal, plays crucial roles in plant resistance to water stress. Because ABA signal production is based on ABA biosynthesis, the regulation of NCED, a key enzyme in the ABA biosynthesis pathway, is normally thought of as the sole factor controlling ABA signal production. Here we demonstrate that ABA catabolism in combination with a synergistic regulation of ABA biosynthesis plays a crucial role in governing ABA signal production. Water stress induced a significant accumulation of ABA, which exhibited different patterns in detached and attached leaves. ABA catabolism followed a temporal trend of exponential decay for both basic and stress ABA, and there was little difference in the catabolic half-lives of basic ABA and stress ABA. Thus, the absolute rate of ABA catabolism, i.e. the amount of ABA catabolized per unit time, increases with increased ABA accumulation. From the dynamic processes of ABA biosynthesis and catabolism, it can be inferred that stress ABA accumulation may be governed by a synergistic regulation of all the steps in the ABA biosynthesis pathway. Moreover, to maintain an elevated level of stress ABA sustained activation of NCED3 should be required. This inference was supported by further findings that the genes encoding major enzymes in the ABA biosynthesis pathway, e.g. NCED3, AAO3 and ABA3 were all activated by water stress, and with ABA accumulation progressing, the expressions of NCED3, AAO3 and ABA3 remained activated. Data on ABA catabolism and gene expression jointly indicate that ABA signal production is controlled by a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism.     

NF-κB信号通路在大鼠肝再生中调节肝细胞增殖的机理研究

为了解大鼠肝再生中肝细胞NF-κB信号通路对肝细胞增殖的调节作用,用Rat Genome 230 2.0芯片检测大鼠肝再生中NF-κB信号通路相关基因表达变化发现,芯片含138个NF-κB信号通路基因,其中46个基因与大鼠肝再生相关.用Ingenuity Pathway Analysis 9.0(IPA)软件解析上述基因表达变化预示的该信号通路调节肝细胞增殖作用发现,该通路的白细胞介素-1(IL-1)途径在大鼠肝再生起始阶段促进肝细胞增殖,生长因子(GF)途径在进展阶段促进肝细胞增殖,肿瘤坏死因子-α(TNF-α)途径在起始阶段促进肝细胞增殖,终止阶段抑制肝细胞增殖.     

Toll样受体信号通路的3条途径在大鼠肝再生中抑制库普弗细胞免疫反应

为从基因转录水平了解大鼠肝再生中Toll样受体信号通路调节库普弗细胞免疫反应的途径和方式,首先建立大鼠2/3肝切除(partial hepatectomy,PH)模型,从中分离库普弗细胞进行基因微阵列分析.发现Toll样受体信号通路的23个基因及其调节免疫反应的62个基因与大鼠肝再生相关.基因协同作用(Ep(t)值)和同类提取法分析表明,大鼠肝再生进展阶段,Toll样受体信号通路通过TLR/NF-κB,TLR/MAPK,TLR/IRF等3条途径和TLR4,MAL,UNC93B1,AP1S2,IRF1等5个关键基因抑制库普弗细胞免疫反应.     

基于距离相关性的乳腺癌通路串扰研究

乳腺癌(Breast Cancer, BC)作为女性最常见的恶性肿瘤迄今为止起因尚不明确,近年来针对单个基因或单条信号通路(pathway)的研究难以分析疾病的复杂发病机理。考虑到信号传导通路之间普遍存在相互关联和相互串扰的分子生物学特性,本文从基因之间的关联性出发,首先基于互信息(Mutual Information,MI)算法提取出了BC患病和健康对照样本中关联度具有明显变化的基因作为特征基因,在此基础上,基于KEGG通路分析获取特征基因所涉及的信号传导通路,并利用距离相关性(Distance Correlation,DC)算法度量它们之间的串扰关系,最终探寻到26条BC患病前后串扰关系变化较大的通路,通过生物学分析得到：胰岛素信号通路(Insulin signaling pathway)、I型糖尿病信号通路(Type I diabetes mellitus pathway)、核糖体(Ribosome pathway)信号通路等通路间的串扰及特征基因的显著变化对BC的发生和发展具有重要的推动作用,研究结果为探寻BC的致病机理提供了新的思路和有益的支撑。     

信号转导通路与异常黑胆质证NEI网络功能紊乱的关系

 为探讨信号转导通路与异常黑胆质证神经-内分泌-免疫(NEI)网络功能紊乱的关系,采用基因芯片技术检测异常黑胆质证与非异常黑胆质(异常血液质、异常黏液质、异常胆液质)证白细胞结构基因表达水平,筛选差异表达基因,利用生物信息学技术分析差异表达基因参与的相关信号转导通路。芯片结果提示,与非异常黑胆质证相比,异常黑胆质证白细胞中有75个结构基因表达上调,生物信息学分析显示差异表达基因中富集到信号转导生物学过程的基因有12个,这些基因主要涉及MAPK、Toll样受体和Wnt信号转导通路等。由此可见,MAPK、Toll样受体、Wnt信号转导通路在异常黑胆质证患者体内存在异常激活现象,这可能与异常黑胆质证神经-内分泌-免疫网络功能紊乱密切相关。     

AhBG1转基因拟南芥的ABA敏感性和抗旱性研究

为探究花生基因AhBG1对拟南芥ABA敏感性和抗旱性的影响,以过表达AhBG1拟南芥为材料,检测其ABA敏感性及脱水处理下ABA质量分数、叶片失水率、干旱存活率及ABA稳态相关基因表达变化. 结果表明:AhBG1是编码花生β-葡萄糖苷酶的家族成员,定位于细胞质;与野生型相比,AhBG1过表达拟南芥植株在干旱条件下体内ABA水平提高,干旱存活率增加,增强有关生物合成途径和信号转导途径相关基因上调,抑制氧化代谢途径相关基因表达. AhBG1蛋白可能催化ABA-GE形成ABA,提高植物体内ABA的质量分数,通过影响ABA稳态相关基因的表达从而提高植物的抗旱性.     

基于人类线粒体基因功能网络的线粒体蛋白功能预测

本研究旨在利用生物信息学的方法建立高可信度线粒体基因清单,通过整合14个全基因组和线粒体水平的异质组学证据,利用朴素贝叶斯模型建立了线粒体基因功能网络,然后基于此网络预测线粒体相关KEGG pathway新的组件,确定部分线粒体基因功能.本研究预测得到78个线粒体相关KEGG pathway新的组件.     

基于表达谱分析筛选肾母细胞瘤关键基因

为探究肾母细胞瘤(Nephroblastoma)发生的关键基因,并筛选出潜在的治疗靶点及生物标志,采用由GEO数据库获取的基因芯片GSE11151和GSE53224,经归一化处理后,通过GO和KEGG分析筛选出差异基因,并通过构建蛋白互作网络获得其中的关键基因.总计获得差异基因404个,其中上调基因385个,下调基因19个.PMCH、CCR5、CCR7、RGS1和KNG1作为关键基因,涉及趋化因子信号通路、G蛋白偶联信号通路,参与肿瘤微环境的形成.这5个关键基因在肾母细胞瘤的发生中有着重要作用,并可能作为潜在治疗靶点及生物标志.     

不同温度下环渤海典型湿地沉积物中二苯并噻吩降解率与功能基因响应关系研究

为了揭示不同温度下环渤海典型湿地沉积物中二苯并噻吩(DBTs)的降解途径, 选择辽河口芦苇湿地、天津北大港滩涂湿地和黄河河口湿地的3种不同湿地沉积物, 在模拟季节性温度条件下, 培养56天, 测定DBT的降解率, 分析DBT降解功能基因的丰度, 建立DBT降解率与功能基因群组定量响应关系模型, 解析不同温度下3种湿地沉积物中DBT的降解途径。实验结果表明, 3种湿地沉积物中DBT的降解率均随培养温度升高而升高, 4ºC培养时, DBT的降解率排序为黄河河口湿地>天津北大港滩涂湿地>辽河口芦苇湿地; 30ºC培养时, DBT的降解率排序为北大港滩涂湿地>黄河河口湿地>辽河口芦苇湿地; catA与dszB基因影响DBT的降解速率。低温条件和中温条件下, 在3种湿地中, 代表Kodama途径的nagAc/nahAc和nidA基因分别起主要作用, 代表4S途径的dszB基因在黄河河口湿地及北大港滩涂湿地中有重要作用。     

基于网络药理学与分子对接探索人参-五味子配伍治疗特发性肺间质纤维化的分子机制

基于网络药理学与分子对接方法,探讨中药人参-五味子配伍治疗特发性肺间质纤维化(idiopathic pulmonary fibrosis,IPF)的潜在分子机制.通过GeneCards、CTD、GEO等数据库预测IPF疾病靶标基因,从TCMSP平台筛选人参-五味子有效活性成分及其治疗靶标,构建中药-活性成分-靶标基因调...     

Involvement of Jasmonate-signaling pathway in the herbivore-induced rice plant defense

The expression patterns of eight defense- related genes in the herbivore-infested and jasmonate- treated (jasmonic acid, JA and its derivative MeJA) rice leaves were analyzed using RT-PCR. The results showed that Spodoptera litura Fabricius (Lepidoptera: Noctuidae) herbi-vory induced the expression of lipoxygenase (LOX) and al-lene oxide synthase (AOS) genes that are involved in the jasmonate-signaling pathway. Moreover, S. litura damage resulted in the expression of farnesyl pyrophosphate syn-thase (FPS), Bowman-birk proteinase inhibitor (BBPI), phenylalanine ammonia-lyase (PAL) and other rice defense- related genes that were also induced by aqueous JA treat-ment or gaseous MeJA treatment. These indicated that in rice leaves, the JA-related signaling pathway was involved in the S. litura-induced chemical defense. Mechanical damage and brown planthopper (BPH), Nilaparvata lugens (St錶) (Homoptera: Delphacidae) damage induced the expression of LOX gene, but both treatments did not induce the expression of AOS gene. However, BPH damage induced the expression of acidic pathogen-related protein 1 (PR-1a), Chitinase (PR-3), and PAL genes, which is involved in the salicylate- signaling pathway. It was suggested that salicylate-related signaling pathway or other pathways, rather than jas-monate-signaling pathway was involved in the BPH-induced rice plant defense.     

A bioinformatic evaluation of potential allergenicity of 85 candidate genes in transgenic organisms

The potential of genetically modified organisms(GMOs) to increase allergenicity or predispositions to allergies has attracted much attention.An approach that will properly and holistically evaluate the allergenicity of GMOs is yet to be found.Here,85 transgenes that have been reported in both international and domestic studies during recent years are summarized case by case;49 of the transformed genes were from plant sources and 36 were from animal sources.EVALLERTM,a web server for the in silico assessment of potential protein allergenicity,was used to evaluate the potential of the transgenic proteins as allergens.The biomedical journals listed in Highwire(http://highwire.stanford.edu/) were searched and reviewed to decipher whether any of the transformed genes were linked to allergenicity or human health.The EVALLER analysis identified 5 allergenic genes,whilst our literature review found 11 genes that were either related to allergic cases or to clinical adverse events;all 16 of these genes have been used in GMOs.The analysis pathway that we have developed can help guide the selection of genes to be used in genetic modification.The pathway also provides a paradigm for allergenicity analysis of transgene candidates.     

AA818342等6个新基因参与大鼠再生肝8种细胞的PLC信号转导

为了解AA818342、BM389035、BF289002、BF403759、AI170687、AI715484等6个新基因在PLC信号通路中的作用及与大鼠肝再生的相关性,分离大鼠再生肝8种细胞,检测它们的基因表达变化,分析新基因与已知基因的序列同源性、共表达关系及参与的生理活动.结果表明,AA818342与col8a1同源,在30 h和72 h再生肝的卵圆细胞中表达下调,在各期再生肝的库普弗细胞中表达上调.BM389035与itga1同源,在168 h再生肝的树突状细胞中表达下调.BF289002与gnai1同源,在12 h和168 h再生肝的卵圆细胞表达上调.BF403759与cacna1d同源,在2 h再生肝的星形细胞表达上调.AI170687与mef2c同源,在36 h再生肝的树突状细胞中表达下调.AI715484与prkce同源,在2 h再生肝的星形细胞中表达上调.上述基因转录谱预示,AA818342等6个新基因属于PLC信号通路成分,参与大鼠再生肝8种细胞的PLC信号转导.     

The secretion of lecithinase of Pseudomonas alcaligenes S2 was via type Ⅱ secretion pathway

Strain S2 is a lecithin （or phosphatidylcholine）- solubilizing bacterium, which was isolated from the rice rhizosphere in rural areas of Beijing, China. On the basis of a polyphasic study involving phenotypic tests, physiological and biochemical tests, 16S rDNA sequence analysis, G＋C content determination and DNA-DNA hybridizations analysis, strain S2 was identified as Pseudomonas alcaligenes. R alcaligenes S2 was mutagenized with Tn5 and four mutants showing decreased or increased solubilizing ability of lecithin were isolated based on the halo size around colonies on the solid plate supplemented with egg yolk. To characterize the genes of R alcaligenes S2 involved in solubilization of lecithin, the EcoR I fragments of the chromosomes from the four mutant strains carrying a single transposon were cloned, and the DNA sequences flanking the Tn5 were determined. The Tn5 insertion sites in the mutants M808, M1329 and M1400, showing decreased solubilizing ability of lecithin, were found to be located in the xcpS, xcpX and xcpW , respectively, whose products XcpS, XcpX and XcpW were the components of type Ⅱ secretion pathway. Complementation of xcpS, xcpX and xcpW could restore the corresponding mutants M808, M1329 and M1400 to solubilize lecithin. The data suggested that mutation in one of these xcp genes would lead to the absence of mature lecithinase secretion into the extracellular medium. The data also indicated that the secretion of lecithin-hydrolyzing enzyme of R alcaligenes was via type Ⅱ secretion pathway. In the mutant M20 showing increasing lecithin-hydrolyzing activity, the interrupted gene showed 86% identity with chpA of Pseudomonas aeruginosa PAO1, whose product plays an important role in controlling twitching motility of the bacterial ceils.