耐热性碱性磷酸酯酶作为非放射性标记物的研究

通过生物素与亲和素－酶复合物系统或地高辛与抗地高辛－酶复合物系统可把酶间接标记到探针上．Ｒｅｎｚ等通过不同的化学方法直接把酶标记到探针上［１～３］．耐热性碱性磷酸酯酶ＦＤ－ＴＡＰ（ｔｈｅｒｍｏｓｔａｂｌｅａｌｋａｌｉｎｅｐｈｏｓｐｈａｔａｓｅ）具有耐...     

Perfect Terahertz Absorption with Graphene Surface Plasmons in the Modified Otto Configuration

Perfect terahertz (THz) absorption in the modified Otto configuration with the insertion of monolayer graphene sheet has been numerically demonstrated. This perfect absorption originates from the enhancement of the electrical field owing to the excitation of the transverse magnetic (TM) polarized surface plasmons at the interface of two dielectrics with monolayer graphene. It is found that the absorption peak occurs at the specific incident angles, which can be employed for realizing the angular absorbers. We further demonstrate that the angle of the peak absorption and the corresponding wavelength can be manipulated by changing the Fermi energy of monolayer graphene sheet via electrostatic biasing. Moreover, the behaviors of the perfect absorption are strongly dependent on the dielectric constants and thicknesses of the surrounding dielectrics.     

Mammalian <Emphasis Type="Italic">CYP2E1</Emphasis> gene triggered changes of relative ions fluxes,CaM content and genes expression profiles in <Emphasis Type="Italic">Petunia hybrida</Emphasis> cells to enhance resistance to formaldehyde

The influence of light quality and cytokinin content in media on growth, development, photosynthetic pigments and secondary metabolite content of Myrtus communis L. was evaluated in an in vitro culture. Various treatments with light emitting diodes (LEDs): 100% blue (B), a mix of 70% red and 30% blue (RB) and 100% red were applied and compared with a traditional fluorescent lamp as control. Axillary shoots were incubated on Murashige and Skoog medium with 30 g dm^?3 sucrose, 0.5% BioAgar, 0.5 μM 1-naphthaleneacetic acid and different concentrations of 6-benzyladenine (BA): 1, 2.5 and 5 µM. Cultures were maintained for 6 weeks in 23/21?±?1 °C (day/night), 80% relative humidity and 16/8 h photoperiod; photosynthetic photon flux density (PPFD) was 35 µmol m^?2 s^?1 in all treatments. Light spectra and BA content in media affected biometrical and phytochemical M. communis properties. Red LEDs and 5 µM BA resulted in the highest multiplication rate. The highest shoots were obtained under red LEDs, but with the lowest concentration of cytokinin in media. Fresh weight was greatest on LEDs containing blue light in the spectrum (B and RB); moreover, 5 µM BA increased dry weight. Photosynthetic pigment levels were lower under LED light compared to control lamps. Phenolic acids and flavonoids were identified in M. communis leaf extracts. Myricetin was the major constituent with highest concentration under red LEDs and highest BA level.     

Elevated Plasma SPARC Levels Are Associated with Insulin Resistance,Dyslipidemia, and Inflammation in Gestational Diabetes Mellitus

Objective

Recent studies suggested that secreted protein acidic and rich in cysteine (SPARC), a novel adipokine, is a key player in the pathology of obesity and type 2 diabetes. We aimed to determine whether concentrations of SPARC were altered in patients with gestational diabetes mellitus (GDM) compared to normal glucose tolerance (NGT) controls and to investigate the relationships between SPARC and metabolic parameters in pregnant women.

Design/Methods

Cross-sectional study of 120 pregnant women with GDM and 60 controls with NGT, in a university hospital setting. Plasma levels of SPARC, adiponectin, fibroblast growth factor 21 (FGF21), insulin and proinsulin were determined by ELISA.

Results

GDM women had higher SPARC and lower adiponectin than NGT subjects; no difference was found in FGF21. SPARC levels were the lowest in subjects in the third tertile of insulin sensitivity index (ISI_OGTT) and correlated positively with pre-pregnant BMI, insulin and 3 h glucose during 100-g OGTT, HOMA-IR, fasting proinsulin, hsCRP and white blood cells count, and negatively with ISI_OGTT, when adjusting for gestational age. Triglyceride (TG), Apolipoprotein A1, apolipoprotein B and lipoprotein (a) correlated with SPARC in partial Pearson correlation. Correlations between SPARC with adiponectin, systolic blood pressure and TG were marginally significant in partial Spearman correlation analysis. In multivariate regression analysis, SPARC was an independent negative indicator of ISI_OGTT.

Conclusions

SPARC levels are correlated significantly with inflammation and may also be correlated with dyslipidemia and represent an independent determinant of insulin resistance in late pregnancy, indicating a potential role of SPARC in the pathophysiology of GDM.     

MicroRNA-7 arrests cell cycle in G1 phase by directly targeting CCNE1 in human hepatocellular carcinoma cells

Growing evidence has demonstrated that the aberrant expression of miRNA is a hallmark of malignancies, indicating the important roles of miRNA in the development and progression of cancer. MiR-7 is considered as a tumor suppressor miRNA in multiple types of cancer. However, the role of miR-7 in human hepatocellular carcinoma (HCC) and its underlying mechanism remain elusive. In this study, we found that overexpression of miR-7 arrested cell cycle at G1 to S transition in HCC. By combinational use of bioinformatic prediction, reporter assay, quantitative real-time PCR (qRT-PCR) and Western blot, we confirmed that CCNE1, an important mediator in G1/S transition is one of new direct target genes of miR-7. Further studies revealed that silencing of CCNE1 recapitulated the effects of miR-7 overexpression, whereas enforced expression of CCNE1 reversed the suppressive effects of miR-7 in cell cycle regulation. Finally, analysis of qRT-PCR showed a reciprocal relationship between miR-7 and CCNE1 in clinical cancer tissues and multiple types of tumor cell lines. These findings indicate that miR-7 exerts tumor-suppressive effects in hepatocarcinogenesis through the suppression of oncogene CCNE1 expression and suggest a therapeutic application of miR-7 in HCC.     

基于复合叶片特征的计算机植物识别方法

该文探讨如何根据植物的叶片特征,利用图像处理和机器学习的方法对植物进行分类。鉴于现有的叶片分类系统多采用单一的特征,如几何和纹理等,仅能在小规模数据库上得到较好的结果。然而,随着样本种类的增多,单一特征在不同种类叶片之间的相似性非常明显,致使分类正确率降低。该研究使用多种复合特征,并提出了原创的预处理方法以及宽度、叶缘频率特征,较传统的几何特征更为详尽。研究结果显示,复合特征可以有效避免算法过拟合问题,使之适用于更大的数据库。通过提取21类植物的叶片宽度、颜色、叶缘和纹理共292维特征,对1 915张数字图像进行了分类,正确率达到93%,并分析了各类特征对分类结果的影响。研究结果表明,在不影响分类正确率前提下,可将特征减少到约100维。     

Crystal structure of cell adhesion molecule nectin-2/CD112 and its binding to immune receptor DNAM-1/CD226

The nectin and nectin-like molecule (Necl) family includes important cell adhesion molecules (CAMs) characterized by their Ig-like nature. Such CAMs regulate a broad spectrum of cell-cell interactions, including the interaction between NK cells and cytotoxic T lymphocytes (CTLs) and their target cells. CAM members nectin-2 (CD112) and Necl-5 (CD155) are believed to form homodimers (for nectin-2) or heterodimers in their functions for cell adhesion, as well as to interact with immune costimulatory receptor DNAX accessory molecule 1 (DNAM-1) (CD226) to regulate functions of both NK and CTL cells. However, the structural basis of the interactive mode of DNAM-1 with nectin-2 or Necl-5 is not yet understood. In this study, a soluble nectin-2 Ig-like V-set domain (nectin-2v) was successfully prepared and demonstrated to bind to both soluble ectodomain and cell surface-expressed full-length DNAM-1. The 1.85-? crystal structure of nectin-2v displays a perpendicular homodimer arrangement, revealing the homodimer characteristics of the nectin and Necls. Further mutational analysis indicated that disruption of the homodimeric interface of nectin-2v led to a failure of the homodimer formation, as confirmed by crystal structure and biochemical properties of the mutant protein of nectin-2v. Interestingly, the monomer mutant also loses DNAM-1 binding, as evidenced by cell staining with tetramers and surface plasmon resonance assays. The data indicate that interaction with DNAM-1 requires either the homodimerization or engagement of the homodimeric interface of nectin-2v. These results have implications for immune intervention of tumors or autoimmune diseases in the DNAM-1/nectin-2-dependent pathway.     

He—Ne激光对君子兰幼果和胡萝卜根的愈伤组织形成及生长的影响

利用6mv的He—Ne激光器,每天对君子兰幼果、胡萝卜根的外植体辐照5分钟,连续辐照20天,对愈伤组织的形成和生长有一定的促进作用。但同样条件下,辐照10分钟,对君子兰幼果,胡萝卜根的愈伤组织形成和生长都有明显的抑制作用。     

激光辐照真菌的酯酶,淀粉酶同工酶研究

本文报导了用He—Ne激光辐照真菌米曲酶的酯酶同工酶和淀粉同工酶的分析研究结果,实验表明激光对米曲霉同工酶有一定的影响。