核磁共振技术在土壤-植物-大气连续体研究中的应用

植物体内的水分状态与传输过程是土壤-植物-大气连续体(SPAC)水分传输理论的核心内容,也是研究植物水分利用与调控的基础.植物体内水分的传输过程受外界环境影响较大,植物需要通过对体内水分状态的适当调整来适应环境变化和维持自身的生长发育.由于蒸发通量、压力室、高压流速仪、热脉冲等传统检测方法往往会对植株造成破坏和损伤,因此难以准确反映和定量描述植物体内水分传输的真实过程.核磁共振技术(NMR)由于其无损、非侵入的特点,在植物水分分布和传输相关研究中日益得到关注.本文概述了NMR在检测植物体内水分分布、传输以及含量测定等方面的研究进展,还分析了目前NMR技术在SPAC系统研究中存在的问题及可能的解决方法,并指出NMR技术将来可能在植物水分生理、植物与环境互作以及水分代谢等相关研究领域的应用.NMR技术在SPAC系统研究中的应用在我国仍处于初级阶段,开发户外便携式、开放式检测仪器是NMR技术在SPAC研究领域进一步应用和推广的关键所在.     

生物实验学习软环境的创设

以情境认知和学习理论为指导,结合生物实验学习实际运用的成效,阐述了生物实验学习软环境创设的操作要领。     

微波杀菌过程中大肠杆菌与金黄色葡萄球菌细胞膜通透性的改变

对细胞膜通透性变化的研究是认识微波杀菌机理的途径之一。用荧光探针检测微波处理后细胞内Ca2 浓度的变化,可以精确地表征细胞膜通透性的改变。选用二乙酸荧光素(FDA)和Fluo-3/AM两种荧光染料,对大肠杆菌(Escherichiacoli)和金黄色葡萄球菌(Staphylococcus aureus)经微波处理后的酯酶活性及细胞膜通透性进行研究,结果表明大肠杆菌与金黄色葡萄球菌的胞内非特异性酯酶(NSE)活性及细胞膜通透性的变化情形有所不同。在50℃、55℃、60℃和65℃微波处理条件下,大肠杆菌细胞膜通透性分别增加了20.7%、28.1%、74.8%、89.8%,而金黄色葡萄球的增加不显著,分别比对照组提高了4.1%、6.0%、21.9%和19.7%。细胞膜通透性的改变与微生物致死率有一定的相关性,也可能是微波杀菌非热效应的表现之一。     

草地螟寄生蝇与寄主间的关系及控害作用

草地螟寄生蝇是草地螟Loxotego stictialisL.的重要天敌,但其发生种类、控害作用尚不明确。通过室内饲养,结合历年田间调查对康保县草地螟寄生蝇种类、田间分布、寄生率及消长规律进行研究,结果表明康保县草地螟寄生蝇发生种类有5种。田间呈聚集分布,种群数量大,寄生率高,控害作用显著。对开展草地螟预测预报,保护利用天敌资源和综合治理提供了科学依据。     

Proteome analysis of hepatocellular carcinoma by two-dimensional difference gel electrophoresis: novel protein markers in hepatocellular carcinoma tissues

Hepatocellular carcinoma (HCC) is a highly malignant tumor, and chronic infection with hepatitis B virus is one of its major risk factors. To identify the proteins involved in HCC carcinogenesis, we used two-dimensional fluorescence DIGE to study the differentially expressed proteins in tumor and adjacent nontumor tissue samples. Samples from 12 hepatitis B virus-associated HCC patients were analyzed. A total of 61 spots were significantly up-regulated (ratio >/= 2, p 相似文献   

蛋白激酶C对血管内皮细胞锚蛋白、CD44表达及亚细胞分布的影响

通过外源性底物对[γ-32P]-ATP的摄入量来测定豆蔻酰佛波醇乙酯(phorbol-myristate-acetate,PMA)处理后的人脐静脉内皮细胞(humanumbilicalveinendothelialcells,HUVECs)膜蛋白激酶C(proteinkinaseC,PKC)的活性;利用间接免疫荧光标记和Western印迹方法分析蛋白激酶C活性对锚蛋白及CD44的亚细胞分布及蛋白质表达的影响。结果发现HUVECs的锚蛋白及CD44表达水平趋势与PKC活性变化相吻合;PKC活化导致CD44在细胞膜上呈聚集状,而锚蛋白则移位并聚集于CD44处;PKC抑制剂能抑制PKC活化所带来的上述作用。结果表明PKC活化通过磷酸化作用能上调锚蛋白及CD44表达,并同时导致二者发生一致性运动及共分布。     

芽孢杆菌B3的鉴定及其对常见污染真菌的拮抗作用

从平菇废弃培养料中分离获得一株细菌B3,通过对其进行形态学、培养特征比较研究和16SrDNA序列分析,鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。在与常见的三种食用菌污染真菌脉孢菌(Neurospora sp.)、木霉(Trichoderma sp.)及鬼伞(Coprinus sp.)分别进行对峙培养时,都有明显的抑菌作用,形成的抑菌带分别为0.38cm、0.57cm及0.56cm,而与平菇(Pleurotus ostreatus)、鸡腿菇(Coprinus comatus)及草菇(Volvariella volvacea)分别进行对峙培养时,除对草菇有明显的抑制作用外,对平菇和鸡腿菇的抑制作用很小。在混接B3菌株麸皮菌剂栽培料培养基上,B3菌株对三种污染真菌的抑制作用都很明显;可抑制木霉分生孢子形成、脉孢菌分生孢子萌发及鬼伞菌丝扩展;但不抑制平菇菌丝的生长。     

Complete genome sequence of the probiotic bacterium Lactobacillus casei LC2W

Lactobacillus casei LC2W, a patented probiotic strain (Z. Wu, European patent EP 1642963 B1, February 2009), has been isolated from Chinese traditional dairy products and implemented in industrial production as starter culture. Here we present the complete genome sequence of LC2W and the identification of a gene cluster implicated in the biosynthesis of exopolysaccharides.     

Exosomes derived from umbilical cord mesenchymal stem cells alleviate viral myocarditis through activating AMPK/mTOR‐mediated autophagy flux pathway

Human umbilical cord mesenchymal stem cell‐derived exosomes (hucMSC‐exosomes) have been implicated as a novel therapeutic approach for tissue injury repair and regeneration, but the effects of hucMSC‐exosomes on coxsackievirus B3 (CVB3)‐induced myocarditis remain unknown. The object of the present study is to investigate whether hucMSC‐exosomes have therapeutic effects on CVB3‐induced myocarditis (VMC). HucMSC‐exosomes were identified using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and Western blot. The purified hucMSC‐exosomes tagged with PKH26 were tail intravenously injected into VMC model mice in vivo and used to administrate CVB3‐infected human cardiomyocytes (HCMs) in vitro, respectively. The effects of hucMSC‐exosomes on myocardial pathology injury, proinflammatory cytokines and cardiac function were evaluated through haematoxylin and eosin (H&E) staining, quantitative polymerase chain reaction (qPCR) and Doppler echocardiography. The anti‐apoptosis role and potential mechanism of hucMSC‐exosomes were explored using TUNEL staining, flow cytometry, immunohistochemistry, Ad‐mRFP‐GFP‐LC3 transduction and Western blot. In vivo results showed that hucMSC‐exosomes (50 μg iv) significantly alleviated myocardium injury, shrank the production of proinflammatory cytokines and improved cardiac function. Moreover, in vitro data showed that hucMSC‐exosomes (50 μg/mL) inhibited the apoptosis of CVB3‐infected HCM through increasing pAMPK/AMPK ratio and up‐regulating autophagy proteins LC3II/I, BECLIN‐1 and anti‐apoptosis protein BCL‐2 as well as decreasing pmTOR/mTOR ratio, promoting the degradation of autophagy flux protein P62 and down‐regulating apoptosis protein BAX. In conclusion, hucMSC‐exosomes could alleviate CVB3‐induced myocarditis via activating AMPK/mTOR‐mediated autophagy flux pathway to attenuate cardiomyocyte apoptosis, which will be benefit for MSC‐exosome therapy of myocarditis in the future.