内蒙古赛罕乌拉国家级自然保护区猞猁食物构成初步分析

猞猁(Lynxlynx)是内蒙古赛罕乌拉国家级自然保护区内的顶级捕食者,在维持该地区生态平衡和调节猎物数量上具有重要地位。分析猞猁粪便样品残留物不仅能明确其猎物构成,了解与同域分布其他捕食者的关系,还能为制定物种保护措施和栖息地管理策略提供科学参考。本研究在2006至2008年间利用样线法在该区域收集到35份猞猁粪便样品。通过相对出现频率法对粪样进行食性分析,发现猞猁的主要食物组成以蒙古兔(Lepus tolai,30.85%)和植物(28.72%)较多;年度(χ~2=18.696,P <0.001)和季节性(χ~2=74.695,P <0.001)食物构成均存在显著差异。结果表明,蒙古兔在猞猁的食物组成中占最重要地位;猞猁的食物构成与季节有关,寒冷季节捕食大型猎物,而温暖季节捕食的小型猎物更常见。     

Study on the binding mode of a pyrrolotriazin derivative with JAK2 by docking and MD simulation

The pyrrolotriazin derivative 2-(4-(4-((7-(3-(N-methylmethylsulfonamido)phenyl)pyrrolo [2,1-f][1,2,4]triazin-2-yl)amino)phenyl)piperidin-1-yl)acetamide (PPA) is a potential Janus kinase 2 (JAK2) inhibitor. The binding mode between PPA and JAK2 was investigated by using a combined method of docking, molecular dynamics (MD) simulation and binding free-energy calculation. The docking calculations preliminarily indicated that there were two possible binding modes 1 and 2; MD simulations and binding free-energy calculations identified that binding mode 1 was more stable and favourable, with the lower MM-PBSA binding free energy of ?34.00?±?0.17?kcal/mol. Moreover, some valuable binding information is revealed as follows: the inhibitor PPA is suitably located at the ATP-binding site of JAK2 and the hydrophobic interaction plays an essential role. PPA not only interacts with residues Leu855, Val863, Ala880, Tyr931, Leu932 and Leu983 via hydrophobic interaction but also interacts with Ser936 and Asp994 by hydrogen bonds. These two factors are advantageous for PPA to strongly bind to JAK2. These results help to understand the action mechanisms and designing new compounds with a higher affinity to JAK2.     

Preparation of cadmium sulfide nanoparticles and their application for improving the properties of the electrochemical sensor for the determination of enrofloxacin in real samples

An advanced electrochemical sensor for the detection of enrofloxacin (ENR) based on the use of a modified electrode containing cadmium sulfide (CdS) nanoparticles (NPs) is reported. The CdS NPs were synthesized and characterized and then coated onto the electrode to fabricate a modified electrode that exhibited a lower limit of detection of 9.5 × 10^?8 mol·L^?1. This detection limit compares with a traditional electrode that exhibited a concentration detection range of 1.0 × 10^?2 to 1.0 × 10^?7 mol·L^?1. This modified electrode demonstrated good selectivity, reproducibility, response time (<40 s), lifetime (up to 12 wk), and pH range (3.3‐7.2) for the determination of ENR in real samples (eg, pig urine).     

LncRNA FOXC2-AS1 protects cardiomyocytes from doxorubicin-induced cardiotoxicity through activation of WNT1-inducible signaling pathway protein-1

Doxorubicin (Dox) is an anthracycline antibiotic that has been used to treat different cancers. Dox-induced cardiotoxicity is common in clinical practice, while its mechanism is unknown. It has been proved that lncRNA FOXC2-AS1 may promote doxorubicin resistance and WNT1-inducible signaling pathway protein-1 (WISP1) blocks doxorubicin-induced cardiomyocyte death. Our study aimed to investigate the involvement of lncRNA FOXC2-AS1 and WISP1 in doxorubicin-induced cardiotoxicity and to explore their interactions. In our study we observed that FOXC2-AS1 and WISP1 mRNA were downregulated in heart tissues of mice with Dox-induced cardiotoxicity. FOXC2-AS1 and WISP1 mRNA expression were positively correlated in mice with Dox-induced cardiotoxicity but not in healthy mice. Overexpression of FOXC2-AS1 promoted to viability of mice cardiomyocytes under Dox treatment and also increased the expression level of WISP1. In contrast, WISP1 overexpression showed no significant effect on FOXC2-AS1. We therefore conclude that lncRNA FOXC2-AS1 may upregulate WISP1 to protect cardiomyocytes from doxorubicin-induced cardiotoxicity.     

Deficiency of mouse mast cell protease 4 mitigates cardiac dysfunctions in mice after myocardium infarction

Mouse mast cell protease-4 (mMCP4) is a chymase that has been implicated in cardiovascular diseases, including myocardial infarction (MI). This study tested a direct role of mMCP4 in mouse post-MI cardiac dysfunction and myocardial remodeling. Immunoblot and immunofluorescent double staining demonstrated mMCP4 expression in cardiomyocytes from the infarct zone from mouse heart at 28 day post-MI. At this time point, mMCP4-deficient Mcpt4^?/? mice showed no difference in survival from wild-type (WT) control mice, yet demonstrated smaller infarct size, improved cardiac functions, reduced macrophage content but increased T-cell accumulation in the infarct region compared with those of WT littermates. mMCP4-deficiency also reduced cardiomyocyte apoptosis and expression of TGF-β1, p-Smad2, and p-Smad3 in the infarct region, but did not affect collagen deposition or α-smooth muscle actin expression in the same area. Gelatin gel zymography and immunoblot analysis revealed reduced activities of matrix metalloproteinases and expression of cysteinyl cathepsins in the myocardium, macrophages, and T cells from Mcpt4^?/? mice. Immunoblot analysis also found reduced p-Smad2 and p-Smad3 in the myocardium from Mcpt4^?/? mice, yet fibroblasts from Mcpt4^?/? mice showed comparable levels of p-Smad2 and p-Smad3 to those of WT fibroblasts. Flow cytometry, immunoblot analysis, and immunofluorescent staining demonstrated that mMCP4-deficiency reduced the expression of proapoptotic cathepsins in cardiomyocytes and protected cardiomyocytes from H₂O₂-induced apoptosis. This study established a role of mMCP4 in mouse post-MI dysfunction by regulating myocardial protease expression and cardiomyocyte death without significant impact on myocardial fibrosis or survival post-MI in mice.     

Low expression of miR-186-5p regulates cell apoptosis by targeting toll-like receptor 3 in high glucose–induced cardiomyocytes

To investigate the effect and mechanism of microRNA-186-5p (miR-186-5p) on the apoptosis in high glucose (HG)–treated cardiomyocytes. Diabetic cardiomyopathy model was established in cardiomyocytes by stimulating with HG. The expressions of miR-186-5p and toll-like receptor 3 (TLR3) were detected by quantitative polymerase chain reaction or Western blot analysis, respectively. Apoptosis was detected in HG-treated cardiomyocytes by flow cytometry and Western blot analysis. The interaction between miR-186-5p and TLR3 was explored by bioinformatics analysis and luciferase activity assay. Results showed that miR-186-5p expression was downregulated in HG-treated cardiomyocytes and its overexpression reversed HG-induced apoptosis and cleaved caspase-3 protein expression. Moreover, TLR3 was indicated as a target of miR-186-5p and regulated by miR-186-5p. Knockdown of TLR3 suppressed HG-induced apoptosis and cleaved caspase-3 protein expression. Besides, restoration of TLR3 ablated the effect of miR-186-5p on cell apoptosis. Collectively, miR-186-5p attenuated HG-induced apoptosis by regulating TLR3 in cardiomyocytes, providing novel biomarker for treatment of diabetic cardiomyopathy.     

Investigation of the molecular interactions of triclocarban with human serum albumin using multispectroscopies and molecular modeling

Triclocarban (TCC), as a broad spectrum antibacterial agent widely used in personal care products, has recently been recognized as environmental pollutant with the potential of adversely affecting wildlife and human health. However, the behavior of TCC in blood circulatory system and the potential toxicity of TCC at the molecular level have been poorly investigated. In this study, the effect of TCC on human serum albumin (HSA) and the binding mechanism of TCC to HSA were examined using spectroscopic techniques and molecular modeling methods. The fluorescence results suggested that the fluorescence of HSA was quenched by TCC through a static quenching mechanism and nonradiation energy transfer, and TCC was bound to HSA with moderately strong binding affinity via hydrophobic interaction based on the analysis of the thermodynamic parameters. The site marker competitive experiments revealed that TCC bound into subdomain IIA (site I) of HSA. In addition, the results obtained from the circular dichroism, Fourier transform infrared (FT-IR), 8-anilino-1-naphthalenesulfonic acid fluorescence, synchronous fluorescence, three-dimensional fluorescence spectra and dynamic light scattering suggested the change in the microenvironment and conformation of HSA during the binding reaction. Finally, the best binding mode of TCC and specific interaction of TCC with amino acid residues were determined using molecular docking and molecular dynamics simulations. In a word, the present studies can provide a way to help us well understand the transport, distribution and toxicity effect of TCC when it diffused in the human body.

Communicated by Ramaswamy H. Sarma