采用稳定碳同位素法分析白羊草在不同干旱胁迫下的水分利用效率

本研究以黄土高原乡土草种白羊草(Bothriochloa ischaemum(L.)Keng.)为研究对象,采用盆栽控制实验,比较白羊草在3个水分处理(CK80%FC、MS60%FC和SS 40%FC)下的生物量积累和分配模式、瞬时水分利用效率(WUE)、不同部位(新叶、老叶、茎、细根、粗根)的稳定碳同位素组成(δ~(13)C)和碳同位素分辨率(Δ~(13)C)及其相互关系,以及干旱胁迫下影响水分利用效率的主导环境因子。结果表明:1)重度干旱胁迫显著降低植物整体生物量,显著增加根冠比和细根生物量比例;2)随着干旱胁迫加剧,白羊草各器官的δ~(13)C均呈上升趋势,Δ~(13)C呈减小趋势,SS处理不同器官δ~(13)C和Δ~(13)C没有显著差异,CK和MS处理的各器官δ~(13)C均值表现分别为细根粗根老叶新叶茎、细根新叶老叶粗根茎,CK和MS处理Δ~(13)C的值总体呈根叶茎。3)新叶的δ~(13)CNL和Δ~(13)CNL与WUE的相关系数均最大,说明利用稳定碳同位素方法测定白羊草水分利用效率具有可行性。4)不同水分处理的WUE的主导影响因子不同,CK、MS、SS水分处理WUE分别受到叶面温度、大气水汽压亏缺和空气温度的影响最大。为采用稳定碳同位素方法指示白羊草水分利用效率可行性及阐明植物的胁迫响应机制提供理论依据。     

Quantitative detection of BCR–ABL fusion gene and its application in monitoring chronic myeloid leukemia treatment

The BCR–ABL fusion gene in chromosome translocation, t (9; 22), and its product, p210BCR/ABL oncogenic tyrosine kinase, is the underlying molecular mechanism that leads to the development of CML. Quantitative detection of BCR–ABL fusion gene has become a reliable approach to diagnose and monitor CML. The aim of this study was to evaluate a Roche t (9; 22) kit in CML diagnosis, monitoring treatment responses, and identification of relapse. Using BCR–ABL fusion gene-expressing K562 cells, a series of standard samples were prepared and used to establish a curve for the calculation of BCR–ABL fusion gene expression in patient samples. Our results indicate that PCR detection system with aforementioned kit has good reproducibility. In addition, the relative concentration of BCR–ABL measured by PCR was in agreement with the patient’s response to the Imatinib treatment and bone marrow morphology remission. Furthermore, we found that the relative concentration of BCR–ABL fusion gene increased 1–3 months before CML relapse was clinically and cytogenetically diagnosed, suggesting that the PCR-based BCR–ABL fusion gene detection with t (9; 22) kit is able to diagnose the recurrence of CML at least 1 month earlier than the classic cytogenetic analysis. In conclusion, detection of BCR–ABL fusion gene expression in CML using Roche t (9; 22) kit has great clinical value in the primary diagnosis, monitoring treatment responses, and identification of relapse in CML patients.     

Interaction of the disintegrin and cysteine-rich domains of ADAM12 with integrin alpha7beta1

We describe a novel interaction between the disintegrin and cysteine-rich (DC) domains of ADAM12 and the integrin alpha7beta1. Integrin alpha7beta1 extracted from human embryonic kidney 293 cells transfected with alpha7 cDNA was retained on an affinity column containing immobilized DC domain of ADAM12. 293 cells stably transfected with alpha7 cDNA adhered to DC-coated wells, and this adhesion was partially inhibited by 6A11 integrin alpha7 function-blocking antibody. The X1 and the X2 extracellular splice variants of integrin alpha7 supported equally well adhesion to the DC protein. Integrin alpha7beta1-mediated cell adhesion to DC had different requirements for Mn2+ than adhesion to laminin. Furthermore, integrin alpha7beta1-mediated cell adhesion to laminin, but not to DC, resulted in efficient cell spreading and phosphorylation of focal adhesion kinase (FAK) at Tyr397. We also show that adhesion of L6 myoblasts to DC is mediated in part by the endogenous integrin alpha7beta1 expressed in these cells. Since integrin alpha7 plays an important role in muscle cell growth, stability, and survival, and since ADAM12 has been implicated in muscle development and regeneration, we postulate that the interaction between ADAM12 and integrin alpha7beta1 may be relevant to muscle development, function, and disease. We also conclude that laminin and the DC domain of ADAM12 represent two functional ligands for integrin alpha7beta1, and adhesion to each of these two ligands via integrin alpha7beta1 triggers different cellular responses.     

d-Ribose glycates β(2)-microglobulin to form aggregates with high cytotoxicity through a ROS-mediated pathway

β(2)-Microglobulin (β(2)M) modified with advanced glycation end products (AGEs) is a major component of the amyloid deposits in hemodialysis-associated amyloidosis (HAA). However, the effect of glycation on the misfolding and aggregation of β(2)M has not been studied so far. Here we examine the molecular mechanism of aggregate formation of HAA-related ribosylated β(2)M in vitro. We find that the glycating agent d-ribose interacts with human β(2)M to generate AGEs that form aggregates in a time-dependent manner. Ribosylated β(2)M molecules are highly oligomerized compared with unglycated β(2)M, and have granular morphology. Furthermore, such ribosylated β(2)M aggregates show significant cytotoxicity to both human SH-SY5Y neuroblastoma and human foreskin fibroblast FS2 cells and induce intracellular reactive oxygen species (ROS). Presence of the antioxidant N-acetylcysteine (1.0mM) attenuated intracellular ROS and prevented cell death induction in both SH-SY5Y and FS2 cells, indicating that the cytotoxicity of ribosylated β(2)M aggregates depends on a ROS-mediated pathway in both cell lines. In other words, d-ribose reacts with β(2)M and induces the ribosylated protein to form granular aggregates with high cytotoxicity through a ROS-mediated pathway. These findings suggest that ribosylated β(2)M aggregates could contribute to the dysfunction and death of cells and could play an important role in the pathogenesis of β(2)M-associated diseases such as HAA.     

Effect of a traditional Chinese medicine preparation Xindi soft capsule on rat model of acute blood stasis: a urinary metabonomics study based on liquid chromatography-mass spectrometry

Xindi soft capsule is a traditional Chinese medicine preparation which consists of sea buckthorn flavonoids and sea buckthorn berry oil. In this study, a urinary metabonomics method based on the ultra-performance liquid chromatography combined with quadrupole time-of-flight tandem mass spectrometry (UPLC Q-TOF MS) was used to evaluate the efficacy and study the mechanism of traditional Chinese medicine preparation to blood stasis. With pattern recognition analysis (principal component analysis and partial least squares-discriminate analysis) of urinary metabolites, a clear separation of acute blood stasis model group and healthy control group was achieved, the dose groups were located between acute blood stasis model group and healthy control group showing a tendency of recovering to healthy control group, high dose and middle dose were more effective than low dose. Some significantly changed metabolites like cholic acid, phenylalanine and kynurenic acid have been found and identified and used to explain the mechanism. The work shows that the metabonomics method is a valuable tool in the research mechanism of traditional Chinese medicine.     

大黄酚和大黄素甲醚的制备性分离

经系统分离得到大黄酚和大黄素甲醚的混合物后,取该混合物约1g,用少量的氯仿溶解,加入少量的层析用硅胶（100～200目）拌匀,减压使氯仿蒸干。将吸附有大黄酚和大黄素甲醚的硅胶装在已装好的硅胶层析柱的上端,然后进行洗脱。通过实验,得到了最佳分离大黄酚和大黄素甲醚的条件：硅胶与混合物的质量比=150：1;层析柱长与直径的比=23：1;洗脱剂比例：石油醚（60～90℃）：乙酸乙酯（V/V）=17：1;减压淋洗。     

Enzymatic esterification between n-alcohol homologs and n-caprylic acid in non-aqueous medium under microwave irradiation

The enzymatic esterification between n-alcohol homologs and n-caprylic acid catalyzed by lipozyme RM IM (LRI) in microwave field was investigated. Some interesting findings were obtained. The optimum reaction temperature slightly shifted from that in enzymatic esterification by conventional heating. n-Alcohol homologs used in this experiment showed substrate specificity in terms of the odd and even carbon numbers. THF expressed abnormal solvent effect. Whereas in the contrastive enzymatic esterification by conventional heating, the above mentioned substrate specificity and solvent effect were not observed. All the above phenomena could be explained by both thermal and non-thermal effect of microwave on enzyme and substrates. Further investigation revealed that microwave irradiation reduced the apparent activation energy of the enzymatic reaction according to Arrhenius equation, which is considered as one of the causes increasing initial reaction rate.