作者机构：
[Zhou, Xi; Tang, Cheng; Chen, Ping; Zhang, Yunxiao; Liu, Zhonghua; Huang, Ying] Hunan Normal Univ, Coll Life Sci, Changsha 410081, Hunan, Peoples R China.;[Tao, Huai] Hunan Univ Chinese Med, Dept Biochem & Mol Biol, Changsha 410208, Hunan, Peoples R China.
通讯机构：
[Liu, Zhonghua] H;Hunan Normal Univ, Coll Life Sci, Changsha 410081, Hunan, Peoples R China.
关键词：
Jingzhaotoxin-II;Nav1.5;Action mechanism
摘要：
Jingzhaotoxin-II (JZTX-II) is a 32-residue peptide from the Chinese tarantula Chilobrachysjingzhao venom, and preferentially inhibits the fast inactivation of the voltage-gated sodium channels (VGSCs) in rat cardiac myocytes. In the present study, we elucidated the action mechanism of JZTX-II inhibiting hNav1.5, a VGSC subtype mainly distributed in human cardiac myocytes. Among the four VGSC subtypes tested, hNav1.5 was the most sensitive to JZTX-II (EC50 = 125 +/- 4 nM). Although JZTX-II had little or no effect on steady-state inactivation of the residual currents conducted by hNav1.5, it caused a 10 mV hyperpolarized shift of activation. Moreover, JZTX-II increased the recovery rate of hNav1.5 channels, which should lead to a shorter transition from the inactivation to closed state. JZTX-II dissociated from toxin-channel complex via extreme depolarization and subsequently rebound to the channel upon repolarization. Mutagenesis analyses showed that the domain IV (DIV) voltage-sensor domain (VSD) was critical for JZTX-II binding to hNav1.5 and some mutations located in S1-S2 and S3-S4 extracellular loops of hNav1.5 DIV additively reduced the toxin sensitivity of hNav1.5. Our data identified the mechanism underlying JZTX-II inhibiting hNav1.5, similar to scorpion a-toxins, involving binding to neurotoxin receptor site 3. (C) 2015 Elsevier Inc. All rights reserved.
作者机构：
[陈伶利; 宋岚; 张晓青; 钱纯; 李杰; 葛金文] Medical school of Hunan University of Chinese Medicine, Changsha 410208, China
关键词：
适体,核苷酸;tolC蛋白,大肠杆菌;抗药性
摘要：
目的:筛选大肠埃希菌外排泵tolC蛋白的核酸适配体。方法:重组表达大肠埃希菌外排泵外膜蛋白tolC,利用指数富集的配体系统进化技术(stematic evolution of ligand by exponential enrichment,SELEX)从单链DNA文库中筛选出一组能够特异性与其结合的核酸适配体。利用FITC荧光素标记技术检测每轮单链DNA文库与靶蛋白的亲和力,直至亲和力的上升趋于饱和,将最后一轮筛选产物克隆测序,并用DNAman软件分析其二级结构。结果:经过12轮筛选,单链DNA文库与靶标蛋白的亲和力趋向稳定,将第12轮筛选产物克隆测序,对获得的23个适配体进行分析。一级结构分析显示23个适配体并无共同的保守序列,但分别有3对和2对适配体序列完全一致。二级结构预测分析表明,茎环结构为适配体主要的结构形式,提示其可能是适配体与tolC蛋白蛋白特异性结合的基础。根据二级结构特点可将23个适配体分为4个家族,其中20号适配体与靶标蛋白亲和力最高。结论:成功利用SELEX技术筛选获得了特异结合tolC的高亲和力的核酸适配体,为大肠埃希菌耐药干预及机制研究奠定了基础。
摘要：
Oxytocin (OT) was reported to affect cognitive and emotional behavior by action in ventral tegmental area (VTA) and other brain areas. However, it is still unclear how OT activates VTA and related midline nucleus. Here, using patch-clamp recording, we studied the effects of OT on neuron activity in VTA and interfascicular nucleus (IF). OT dose-dependently and selectively excited small neurons located in medial VTA and the majority of IF neurons but not large neurons in lateral VIA. We found the hyperpolarization-activated current (I-h) and the membrane capacitance of OT-sensitive neuron were significantly smaller than those of OT-insensitive neurons. The action potential width of 01-sensitive neurons was about half that of OT-insensitive neurons. The OT effect was blocked by the OT receptor antagonist atosiban and WAY-267464 but not by tetrodotoxin, suggesting a direct postsynaptic activation of OT receptors. In addition, the phospholipase C (PLC) inhibitor U73122 antagonized the depolarization by OT. Both the nonselective cation channel (NSCC) antagonist SKF96365 and the Na+-Ca2+ exchanger (NCX) blocker SN-6 attenuated OT effects. These results suggested that the PLC signaling pathway coupling to NSCC and NCX contributes to the OT-mediated activation of neurons in medial VIA and IF. Taken together, our results indicate OT directly acted on medial WA and especially IF neurons to activate NSCC and NCX via PLC. The direct activation by OT of midbrain neurons may be one mechanism underlying OT effects on social behavior. (C) 2013 Elsevier Ltd. All rights reserved.
摘要：
Schistosomiasis japonicum remains a considerable economic and public health concern in China, the Philippines and Indonesia. Currently available measures to control the unique intermediate host Oncomelania hupensis are frequently associated with severe side effects. Previous studies have demonstrated that linalool-rich extracts from various plants exhibited promising biological activities including cytotoxic, anti-microbial and anti-parasitic properties. We identified the components of leaf extracts from Cinnamomum camphora by gas chromatography coupled to mass spectrometry (GC-MS) and investigated molluscicidal and larvicidal effects of linalool against O. hupensis and Schistosoma japonicium. The ultrastructural alterations in gills, salivary gland, stomach and hepatopancreas of snails were observed under the light microscope and transmission electron microscope, and lesions to tegument of cercaria were examined under a light microscope and fluorescence microscope. We then evaluated the effects of linalool on skin penetration and migration of schistosomula and adult survival by measurement of worm burden and egg counts in Balb/C mice infected with linalool-treated cercariae. In the present work, 44 components were identified from the leaf extracts of C. camphora, of which linalool was the most abundant constituent. Linalool exhibited the striking molluscicidal and larvicidal effects with LC50 = 0.25 mg/L for O. hupensis and LC50 = 0.07 mg/L for cercaria of S. japonicium. After exposure to linalool, damage to the gills and hepatopancreas of the snails, and to the tegument and body-tail joint of cercariae was apparent. In addition, linalool markedly reduced the recovered schistosomulum from mouse skin after challenge infection, and therefore decreased the worm burden in infected animals, but not fecundity of female adults of the parasite. Our findings indicated that linalool might be a novel chemotherapeutic agent against S. japonicium and the snail intermediate host.
作者机构：
[张波] School of Medicine, Hunan University of Chinese Medicine, Changsha 410208;[张波; 张健] Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education, School of Life Sciences, Hunan Normal University, Changsha 410081, China;[周芳亮; 严杰; 卢芳国] School of Medicine, Hunan University of Chinese Medicine, Changsha 410208, China
摘要：
Mesenchymal stem cells (MSCs) are multipotent stem cells that give rise to various cell types of the mesodermal germ layer. Because of their unique ability to home in on injured and cancerous tissues, MSCs are of great potential in regenerative medicine. MSCs also contribute to reparative processes in different pathological conditions, including cardiovascular diseases and cancer. However, many studies have shown that only a small proportion of transplanted MSCs can actually survive and be incorporated into host tissues. The effects of MSCs cannot be fully explained by their number. Recent discoveries suggest that microparticles (MPs) derived from MSCs may be important for the physiological functions of their parent. Though the physiological role of MSC-MPs is currently not well understood, inspiring results indicate that, in tissue repair and anti-cancer therapy, MSC-MPs have similar pro-regenerative and protective properties as their cellular counterparts. Thus, MSC-MPs represent a promising approach that may overcome the obstacles and risks associated with the use of native or engineered MSCs.
摘要：
Three heterocyclic hypervalent organoantimony chlorides RN(CH2C6H4)(2)SbCI (2a R = t-Bu, 2b R = Cy, 2c R = Ph) and their chalcogenide derivatives [RN(CH2C6H4)(2)Sb](2)O (3a R = t-Bu, 3b R = Cy, 3c R = Ph) were synthesized and characterized by techniques such as H-1 NMR, C-13 NMR, X-ray diffraction, and elemental analysis. It is found that the anti-proliferative activity detected over these compounds can be attributed to the coordination bond between the antimony and nitrogen atoms of these compounds. Moreover, a preliminary study on mechanistic action suggests that the inhibition effect is ascribable to cell cycle arrest and cell apoptosis. (C)2014 Elsevier Masson SAS. All rights reserved.
摘要：
The Notch signaling pathway plays versatile roles during heart development. However, there is contradictory evidence that Notch pathway either facilitates or impairs cardiomyogenesis in vitro. In this study, we developed iPSCs by reprogramming of murine fibroblasts with GFP expression governed by Oct4 promoter, and identified an effective strategy to enhance cardiac differentiation through timely modulation of Notch signaling. The Notch inhibitor DAPT (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester) alone drove the iPSCs to a neuronal fate. After mesoderm induction of embryoid bodies initiated by ascorbic acid (AA), the subsequent treatment of DAPT accelerated the generation of spontaneously beating cardiomyocytes. The timed synergy of AA and DAPT yielded an optimal efficiency of cardiac differentiation. Mechanistic studies showed that Notch pathway plays a biphasic role in cardiomyogenesis. It favors the early-stage cardiac differentiation, but exerts negative effects on the late-stage differentiation. Therefore, DAPT administration at the late stage enforced the inhibition of endogenous Notch activity, thereby enhancing cardiomyogenesis. In parallel, DAPT dramatically augmented the expression of Wnt3a, Wnt11, BMP2, and BMP4. In conclusion, our results highlight a practicable approach to generate cardiomyocytes from iPSCs based on the stage-specific biphasic roles of Notch signaling in cardiomyogenesis.
期刊：
American Journal of Pathology,2013年182(3):886-894 ISSN：0002-9440
通讯作者：
Tanowitz, Herbert B.
作者机构：
[Weiss, Louis M.; Desruisseaux, Mahalia S.; Zhao, Dazhi; Factor, Stephen M.; Tanowitz, Herbert B.; Nagajyothi, Fnu; Huang, Huan] Albert Einstein Coll Med, Dept Pathol, Div Parasitol & Trop Med, Bronx, NY 10461 USA.;[Kuliawat, Regina] Albert Einstein Coll Med, Dept Dev & Mol Biol, Bronx, NY 10461 USA.;[Weiss, Louis M.; Desruisseaux, Mahalia S.; Tanowitz, Herbert B.; Singh, Rajat; Schwartz, Gary J.; Pessin, Jeffrey E.] Albert Einstein Coll Med, Dept Med, Div Infect Dis, Bronx, NY 10461 USA.;[Weiss, Louis M.; Desruisseaux, Mahalia S.; Tanowitz, Herbert B.; Singh, Rajat; Schwartz, Gary J.; Pessin, Jeffrey E.] Albert Einstein Coll Med, Dept Med, Div Endocrinol, Bronx, NY 10461 USA.;[Singh, Rajat; Schwartz, Gary J.; Pessin, Jeffrey E.] Albert Einstein Coll Med, Diabet Res Ctr, Bronx, NY 10461 USA.
通讯机构：
[Tanowitz, Herbert B.] A;Albert Einstein Coll Med, Dept Pathol, 1300 Morris Pk Ave, Bronx, NY 10461 USA.
摘要：
Chagas disease, caused by Trypanosoma cruzi, is an important cause of morbidity and mortality primarily resulting from cardiac dysfunction, although T. cruziin fection results in inflammation and cell destruction in many organs. We found that T. cruzi (Brazil strain) infection of mice results in pancreatic inflammation and parasitism within pancreatic beta-cells with apparent sparing of a cells and leads to the disruption of pancreatic islet architecture, beta-cell dysfunction, and surprisingly, hypoglycemia. Blood glucose and insulin levels were reduced in infected mice during acute infection and insulin levels remained low into the chronic phase. In response to the hypoglycemia, glucagon levels 30 days postinfection were elevated, indicating normal a-cell function. Administration of L-arginine and a beta-adrenergic receptor agonist (CL316, 243, respectively) resulted in a diminished insulin response during the acute and chronic phases. Insulin granules were docked, but the lack of insulin secretion suggested an inability of granules to fuse at the plasma membrane of pancreatic beta-cells. In the liver, there was a concomitant reduced expression of glucose-6-phosphatase mRNA and glucose production from pyruvate (pyruvate tolerance test), demonstrating defective hepatic gluconeogenesis as a cause for the T. cruzi-induced hypoglycemia, despite reduced insulin, but elevated glucagon levels. The data establishes a complex, multi-tissue relationship between T. cruzi infection, Chagas disease, and host glucose homeostasis. (Am 3 Pathol 2013, 182:886-894; http:// dx.doi.org/10.1016/j.ajpath.2012.11.027)
