A plethora of painful molecules

Pain is a fundamental experience with a complex and multi-layered neurobiological basis. In recent years a powerful battery of techniques has been brought to bear to unravel the mechanisms by which painful stimuli are transduced and processed. There have been several recent discoveries regarding the molecular transduction mechanisms in nociceptors and novel molecular and cellular mechanisms underlying the spinal processing of painful stimuli. The mechanisms by which sensory neurons initiate hyperalgesia and touch evoked pain (allodynia) have been addressed particularly successfully in recent studies. The rich variety of key molecular players that have emerged in physiological and pathophysiological pain states reflects the sophistication and uniqueness of this vitally important sense.     

Chloroplast phylogeographic patterns of Calligonum sect. Pterococcus (Polygonaceae) in arid Northwest China

To understand the impacts of past climatic change and geological events on the evolutionary history of Calligonum sect. Pterococcus, including C. aphyllum, C. rubicundum and C. leucocladum, a total of 128 individuals from 14 populations, mainly from arid Northwest China, were sampled. Two cpDNA intergenic spacer regions (rpl32‐trnL and ycf6‐psbM) were sequenced and 11 haplotypes were identified. Levels of genetic differentiation between populations was low in C. rubicundum (F_ST = 0.54317, p < 0.001) and C. aphyllum (F_ST = 0.55795), while much higher in C. leucocladum (F_ST = 0.95800, p < 0.001), possibly as an effct of differences in geographic distributions and habitats. Analysis of molecular variance (AMOVA) revealed that most of the total genetic variations occurred among species (72.97%). Among eleven identified haplotypes, only H1 and H2 were shared between C. aphyllum and C. rubicundum, while nine were private for one of the three species. The eleven identified haplotypes were divided into two major clades, but they did not yield three species‐specific lineages. Calligonum sect. Pterococcus therefore not appeared reciprocally monophyletic, more likely due to incomplete lineage sorting than hybridization. Mismatch distribution analysis suggested that only C. aphyllum has experienced recent demographic expansion. Divergence time among the 11 haplotypes was estimated at between 2.84 Ma and 0.06 Ma. Within the two clades, haplotype divergence began in early Pleistocene and mainly occurred during the middle to late Pleistocene and was most likely triggered by Quaternary climatic oscillations and increasing aridity of the region.     

ITMSQ: A software tool for N‐ and C‐terminal fragment ion pairs based isobaric tandem mass spectrometry quantification

Tandem MS (MS2) quantification using the series of N‐ and C‐terminal fragment ion pairs generated from isobaric‐labelled peptides was recently considered an accurate strategy in quantitative proteomics. However, the presence of multiplexed terminal fragment ion in MS2 spectra may reduce the efficiency of peptide identification, resulting in lower identification scores or even incorrect assignments. To address this issue, we developed a quantitative software tool, denoted isobaric tandem MS quantification (ITMSQ), to improve N‐ and C‐terminal fragment ion pairs based isobaric MS2 quantification. A spectrum splitting module was designed to separate the MS2 spectra from different samples, increasing the accuracy of both identification and quantification. ITMSQ offers a convenient interface through which parameters can be changed along with the labelling method, and the result files and all of the intermediate files can be exported. We performed an analysis of in vivo terminal amino acid labelling labelled HeLa samples and found that the numbers of quantified proteins and peptides increased by 13.64 and 27.52% after spectrum splitting, respectively. In conclusion, ITMSQ provides an accurate and reliable quantitative solutionfor N‐ and C‐terminal fragment ion pairs based isobaric MS2 quantitative methods.     

Identification of a Bifunctional UDP-4-keto-pentose/UDP-xylose Synthase in the Plant Pathogenic Bacterium Ralstonia solanacearum Strain GMI1000, a Distinct Member of the 4,6-Dehydratase and Decarboxylase Family

The UDP-sugar interconverting enzymes involved in UDP-GlcA metabolism are well described in eukaryotes but less is known in prokaryotes. Here we identify and characterize a gene (RsU4kpxs) from Ralstonia solanacearum str. GMI1000, which encodes a dual function enzyme not previously described. One activity is to decarboxylate UDP-glucuronic acid to UDP-β-l-threo-pentopyranosyl-4″-ulose in the presence of NAD⁺. The second activity converts UDP-β-l-threo-pentopyranosyl-4″-ulose and NADH to UDP-xylose and NAD⁺, albeit at a lower rate. Our data also suggest that following decarboxylation, there is stereospecific protonation at the C5 pro-R position. The identification of the R. solanacearum enzyme enables us to propose that the ancestral enzyme of UDP-xylose synthase and UDP-apiose/UDP-xylose synthase was diverged to two distinct enzymatic activities in early bacteria. This separation gave rise to the current UDP-xylose synthase in animal, fungus, and plant as well as to the plant Uaxs and bacterial ArnA and U4kpxs homologs.     

镉离子诱导BA/F3β细胞发生奇特的细胞凋亡

细胞凋亡一般都伴随有ＤＮＡ 片段化, 活性氧含量增加, 并能被过量的Ｂｃｌ２ 所抑制。以ＢＡ／Ｆ３β细胞为模型, 利用ＭＴＴ 检测、Ｈｏｃｈｅｓｔ 染色以及透射电镜检测等技术却发现, 镉离子虽然可以诱导该细胞凋亡, 但是这种凋亡没有ＤＮＡ 片段化, 也没有活性氧含量增加。此外, 过量Ｂｃｌ２ 对这种凋亡也没有保护作用。因此, 可以确认镉离子诱导ＢＡ／Ｆ３β细胞发生了奇特的细胞凋亡。     

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   

谷子种质资源抗黑穗病鉴定与过氧化物酶研究

对全国2050份谷子种质资源进行了抗黑穗病鉴定,对不同抗、感黑穗病的谷子种质资源进行了过氧化物酶活性、过氧化物酶同工酶的比较研究。结果表明,谷子不同种质资源对黑穗病的抗性存在着明显的差异。谷子种质资源对黑穗病的抗性比较稳定。谷子感染黑穗病后,抗病品种的过氧化物酶活性明显高于感病品种。过氧化物酶同工酶可以作为一种遗传标记。     

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.     

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.