MicroRNA-138 Suppresses Neutrophil Gelatinase-Associated Lipocalin Expression and Inhibits Tumorigenicity

The expression of neutrophil gelatinase-associated lipocalin (NGAL) is up-regulated in some cancers; therefore NGAL has potential as a tumor biomarker. Although the regulation mechanism for this is unknown, one study has shown that it is likely to involve a microRNA (miRNA). Here, we investigate the relation between miRNA expression and NGAL expression, and the role of NGAL in tumorigenesis. Using miRNA target–detecting software, we analyze the mRNA sequence of NGAL and identify a target site for microRNA-138 (miR-138) in nucleotides 25–53 of the 3′ UTR. We then analyze NGAL and miR-138 expression in three cancer cell lines originating from breast, endometrial and pancreatic carcinomas (the MCF-7, RL95-2 and AsPC-1 cell lines), respectively, using quantitative (real-time) PCR and western blot analysis. Metastasis is a critical event in cancer progression, in which malignant cell proliferation, migration and invasion increase. To determine whether miR-138-regulated NGAL expression is associated with metastasis, the proliferation and migration of the cell line are examined after miR-138 transfection. Using nude mice, we examine both the tumorigenicity of these cell lines and of miR-138-transfected cancer cells in vivo, as well as the effect of treating tumors with an antibody against NGAL. Our results show that these cancer cell lines down-regulate NGAL when miR-138 is highly expressed. Ectopic transfection of miR-138 suppresses NGAL expression and cell migration in RL95-2 and AsPC-1 cells, demonstrating that miR-138-regulated NGAL expression is associated with cell migration. Additionally, injection of the NGAL antibody diminishes NGAL-mediated tumorigenesis in nude mice, and miR-138 transfection of cancer cells reduces tumor formation. As the cell proliferation data showed that the tumor size should be regulated by NGAL-related cell growth. Taken together, our results indicate that NGAL may be a good target for cancer therapy and suggest that miR-138 acts as a tumor suppressor and may prevent metastasis.     

Breaking the 10% Efficiency Barrier in Organic Photovoltaics: Morphology and Device Optimization of Well‐Known PBDTTT Polymers

With the advances in organic photovoltaics (OPVs), the invention of model polymers with superior properties and wide applicability is of vital importance to both the academic and industrial communities. The recent inspiring advances in OPV research have included the emergence of poly(benzodithiophene‐co‐thieno[3,4‐b]thiophene) (PBDTTT)‐based materials. Through the combined efforts on PBDTTT polymers, over 10% efficiencies have been realized recently in various types of OPV devices. This review attempts to critically summarize the recent advances with respect to five well‐known PBDTTT polymers and their design considerations, basic properties, photovoltaic performance, as well as device application in conventional, inverted, tandem solar cells. These PBDTTT polymers also make great contributions to the rapid advances in the field of emerging ternary blends and fullerene‐free OPVs with top performances. Addtionally, new challenges in developing novel photovoltaic polymers with more superior properties are prospected. More importantly, the research of highly efficient PBDTTT‐based polymers provides useful insights and builds fundamentals for new types of OPV applications with various architectures.     

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.     

Protective effects of MLIF analogs on cerebral ischemia-reperfusion injury in rats

The monocyte locomotion inhibitory factor (MLIF) is an anti-inflammatory oligopeptide produced by Entamoeba histolytica. Among its different effects, it inhibits locomotion of human monocytes, hence its original name. The carboxyl-terminal end group Cys-Asn-Ser is the pharmacophore of anti-inflammatory peptide Met-Gln-Cys-Asn-Ser. In this study, the N-terminal of Cys-Asn-Ser was modified. With the aim to enhance the antioxidant ability and penetrability of Cys-Asn-Ser, we designed and synthesized two tetrapeptides Tyr-Cys-Asn-Ser and His-Cys-Asn-Ser. The neuroprotective effects of Tyr-Cys-Asn-Ser and His-Cys-Asn-Ser on focal ischemia reperfusion were investigated, and their pharmacological activities compared with Cys-Asn-Ser were studied. In order to study the mechanism of neuroprotective effect of these peptides, the level of oxidative stress markers malondialdehyde (MDA) and superoxide dismutase (SOD) and pro-inflammatory factors interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and myeloperoxidase (MPO) were detected in brain tissue homogenate.     

Capsaicin inhibits intestinal Cl- secretion and promotes Na+ absorption by blocking TRPV4 channels in healthy and colitic mice

Although capsaicin has been studied extensively as an activator of the transient receptor potential vanilloid cation channel subtype 1 (TRPV1) channels in sensory neurons, little is known about its TRPV1-independent actions in gastrointestinal health and disease. Here, we aimed to investigate the pharmacological actions of capsaicin as a food additive and medication on intestinal ion transporters in mouse models of ulcerative colitis (UC). The short-circuit current (I_sc) of the intestine from WT, TRPV1-, and TRPV4-KO mice were measured in Ussing chambers, and Ca²⁺ imaging was performed on small intestinal epithelial cells. We also performed Western blots, immunohistochemistry, and immunofluorescence on intestinal epithelial cells and on intestinal tissues following UC induction with dextran sodium sulfate. We found that capsaicin did not affect basal intestinal I_sc but significantly inhibited carbachol- and caffeine-induced intestinal I_sc in WT mice. Capsaicin similarly inhibited the intestinal I_sc in TRPV1 KO mice, but this inhibition was absent in TRPV4 KO mice. We also determined that Ca²⁺ influx via TRPV4 was required for cholinergic signaling–mediated intestinal anion secretion, which was inhibited by capsaicin. Moreover, the glucose-induced jejunal I_scvia Na⁺/glucose cotransporter was suppressed by TRPV4 activation, which could be relieved by capsaicin. Capsaicin also stimulated ouabain- and amiloride-sensitive colonic I_sc. Finally, we found that dietary capsaicin ameliorated the UC phenotype, suppressed hyperaction of TRPV4 channels, and rescued the reduced ouabain- and amiloride-sensitive I_sc. We therefore conclude that capsaicin inhibits intestinal Cl^- secretion and promotes Na⁺ absorption predominantly by blocking TRPV4 channels to exert its beneficial anti-colitic action.     

Formation of Adeno-Associated Virus Circular Genomes Is Differentially Regulated by Adenovirus E4 ORF6 and E2a Gene Expression

A central feature of the adeno-associated virus (AAV) latent life cycle is persistence in the form of both integrated and episomal genomes. However, the molecular processes associated with episomal long-term persistence of AAV genomes are only poorly understood. To investigate these mechanisms, we have utilized a recombinant AAV (rAAV) shuttle vector to identify circular AAV intermediates from transduced HeLa cells and primary fibroblasts. The unique structural features exhibited by these transduction intermediates included circularized monomer and dimer virus genomes in a head-to-tail array, with associated specific base pair alterations in the 5′ viral D sequence. In HeLa cells, the abundance and stability of AAV circular intermediates were augmented by adenovirus expressing the E2a gene product. In the absence of E2a, adenovirus expressing the E4 open reading frame 6 gene product decreased the abundance of AAV circular intermediates, favoring instead the linear replication form monomer (Rf_m) and dimer (Rf_d) structures. In summary, the formation of AAV circular intermediates appears to represent a new pathway for AAV genome conversion, which is consistent with the head-to-tail concatemerization associated with latent-phase persistence of rAAV. A better understanding of this pathway may increase the utility of rAAV vectors for gene therapy.     

大肠杆菌F18菌株敏感和抵抗基因型仔猪十二指肠基因表达谱差异分析

文章运用Agilent 双标记表达谱芯片, 基于已建立的苏太猪大肠杆菌F18菌株敏感性和抗性型全同胞配对个体, 分析十二指肠组织基因表达谱差异, 旨在筛选导致仔猪断奶后腹泻和水肿病发生的大肠杆菌F18菌株受体相关基因, 探讨造成大肠杆菌病抗性和敏感性资源家系抗性差异的分子生物学机理。研究结果显示, 以Fold change绝对值大于2倍进行筛选, 在敏感型(GG基因型)对抗性型(AA基因型)配对组中, 差异基因共13个, 其中上调6个, 下调7个, 在以敏感型(AG基因型)对抗性型(AA基因型)配对组中, 共筛选出差异基因6个, 其中上调4个, 下调2个。经GO分析发现差异基因的生物学过程主要涉及免疫应答、胞外区修饰(如糖基化)、细胞黏附、信号转导等。通路发现大肠杆菌F18菌株抵抗性和敏感性差异基因主要涉及糖脂合成代谢以及炎症免疫相关通路, 经芯片筛选出的相关基因的功能还需进一步的研究验证。     

Temporary effect of postharvest UV-C irradiation on gene expression profile in tomato fruit

To obtain an overall view on gene expression during the early stage (24 h) of tomato fruit in response to postharvest UV-C irradiation (4 kJ/m(2)), we performed a microarray analysis by using Affymetrix Tomato Genechip. The results showed that 274 and 403 genes were up- or down-regulated, respectively, more than two folds in postharvest tomato fruit irradiated with UV-C as compared with that in control fruit. The up-regulated genes mainly involve in signal transduction, defense response and metabolism. Conversely, genes related to cell wall disassembly, photosynthesis and lipid metabolism were generally down-regulated. These results opened ways to probe into the molecular mechanisms of the effects of postharvest UV-C irradiation on increased disease resistance, delayed softening, better quality maintenance and prolonged postharvest life in tomato fruit.     

An inducible transgenic Cre mouse line for the study of hippocampal development and adult neurogenesis

The hippocampus is crucial for higher brain functions, such as learning, memory, and emotion. Many diseases like epilepsy and Down's syndrome are associated with abnormalities in early hippocampal development. In addition, adult dentate neurogenesis is thought to be defective in several classes of psychiatric disorders. However, the mechanisms regulating hippocampal development and adult neurogenesis remain unclear. One of the limitations to studying these processes is the scarcity of available specific mouse tools. Here, we report an inducible transgenic Cre mouse line, Frizzled 9‐CreER?, in which tamoxifen administration induces Cre recombinant. Our data show that Cre is expressed in the developing hippocampal primordium, confined to the granule cell layer at P20 and further limited to the subgranular zone in the adult dentate gyrus. Cre recombinase shows very high activity in all of these regions. Thus, this transgenic line will be a powerful tool in understanding the mechanisms of hippocampal development, adult neurogenesis, and associated diseases. genesis 49:919–926, 2011. © 2011 Wiley Periodicals, Inc.     

Crystallization and preliminary X-ray crystallographic analysis of spruce budworm antifreeze protein.

Antifreeze proteins have the ability to bind to ice with high affinity and inhibit further crystal growth. The insect antifreeze protein from spruce budworm exhibits very high thermal hysteresis activity and is implicated in the protection of overwintering larvae from freezing. This protein has been crystallized in 20-25% polyethylene glycol (Mr 6000), 0.4 M NaCl, 0.1 M Tris-HCl, pH 8.5, by vapor diffusion using the hanging drop method. The resulting crystals are very thin (typically <0.01 mm in the shortest dimension), and only after repeated seeding could crystals be grown large enough for data collection using synchrotron radiation. The crystals belong to the monoclinic space group C2, with cell dimensions a = 82.28 A, b = 62.29 A, c = 63.63 A, and beta = 113.7 degrees. Molecules in the asymmetric unit are related by a twofold axis of symmetry with two molecules present. Native data to a resolution of 2.6 A have been collected with 90.3% completeness and a Rsym of 6.9%.