Study on the Interaction Mechanism of 2‐Aminoanthraquinone with Calf Thymus DNA

By utilizing multispectrosopic techniques, the toxic interaction of 2‐aminoanthraquinone (2‐AAQ) with calf thymus deoxyribonucleic acid (ctDNA) was investigated in vitro under simulated physiological conditions. The experimental results proved that 2‐AAQ has a toxic interaction with ctDNA. The binding capacity of DNA with 2‐AAQ is diminishing as the pH value of system increasing in the optimization of experimental condition. Moreover we selected pH 7.4, which is nearly physiological condition to enhance the practical significance. According to the Stern–Volmer equation, the quenching was the static quenching process. And the quenching constant can be derived from the fluorescence quenching spectrogram. Ultraviolet absorption spectra and the change in the fluorescence intensity at different ionic strengths further indicated that there was electrostatic binding between 2‐AAQ and ctDNA. The circular dichroism experiment showed that the DNA conformation varied from B to A conformation. The basic group enhanced after 2‐AAQ embedding. The double helix is more compact, and the DNA conformation changes. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:272‐278, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21487     

南海东海岛沉积物分离细菌的鉴定及其抑菌活性

[背景] 海洋微生物在活性物质开发方面具有巨大的应用前景,而目前有关南海东海岛微生物的研究鲜少。[方法] 对从东海岛沉积物中分离纯化的海洋细菌,采用形态学观察、生理生化以及16S rRNA基因序列的系统发育分析方法进行鉴定;以大肠杆菌（Escherichia coli）、枯草芽孢杆菌（Bacillus subtilis）和金黄色葡萄球菌（Staphylococcus aureus）作为指示菌,测定其抑菌活性;对具有抑菌活性的菌株扩增聚酮合酶（Polyketide synthase I,PKSI）基因,并与已知的PKSI氨基酸序列比对;选择具有PKSI基因的代表菌株,检测菌株及其发酵抑菌物的稳定性。[结果] 分离纯化到25株海洋细菌,分属于不动杆菌属（Acinetobacter）、交替单胞菌属（Alteromonas）、芽孢杆菌属（Bacillus）、嗜冷杆菌属（Psychrobacter）、假交替单胞菌属（Pseudo-alteromonas）、海洋单胞菌属（Oceanimonas）、葡萄球菌属（Staphylococcus）、微球菌属（Micrococcus）和海杆菌属（Marinobacter）。12株菌株通过基因筛选检测到PKSI编码基因,其中6株菌株具有抑菌活性和PKSI编码基因,并分属于芽孢杆菌属和交替单胞菌属;PKSI氨基酸序列同源性分析推测菌株DHD-15和DHD-a可能产生新的I型聚酮合酶结构。菌株DHD-15和DHD-L生长温度范围为15-40℃,可耐受10% NaCl高盐以及pH 3和pH 11的酸碱条件,但不耐高温;菌株DHD-15产生的抑菌物质可耐受100℃和pH 11的高温碱性条件,在50℃、pH 9条件下制备和室温保藏条件下抑菌活性较高,其稳定性较好。[结论] 南海东海岛沉积物筛选的细菌种具有抑菌活性,具有产聚酮类活性物质的潜力。     

Binding of tetracycline and chlortetracycline to the enzyme trypsin: spectroscopic and molecular modeling investigations

Tetracycline (TC) and chlortetracycline (CTC) are common members of the widely used veterinary drug tetracyclines, the residue of which in the environment can enter human body, being potentially harmful. In this study, we establish a new strategy to probe the binding modes of TC and CTC with trypsin based on spectroscopic and computational modeling methods. Both TC and CTC can interact with trypsin with one binding site to form trypsin-TC (CTC) complex, mainly through van der Waals' interactions and hydrogen bonds with the affinity order: TC>CTC. The bound TC (CTC) can result in inhibition of trypsin activity with the inhibition order: CTC>TC. The secondary structure and the microenvironment of the tryptophan residues of trypsin were also changed. However, the effect of CTC on the secondary structure content of trypsin was contrary to that of TC. Both the molecular docking study and the trypsin activity experiment revealed that TC bound into S1 binding pocket, competitively inhibiting the enzyme activity, and CTC was a non-competitive inhibitor which bound to a non-active site of trypsin, different from TC due to the Cl atom on the benzene ring of CTC which hinders CTC entering into the S1 binding pocket. CTC does not hinder the binding of the enzyme substrate, but the CTC-trypsin-substrate ternary complex can not further decompose into the product. The work provides basic data for clarifying the binding mechanisms of TC (CTC) with trypsin and can help to comprehensively understanding of the enzyme toxicity of different members of tetracyclines in vivo.     

Analysis of the formation of flower shapes in wild species and cultivars of tree peony using the MADS-box subfamily gene

Tree peony (Paeonia suffricotisa) cultivars have a unique character compared with wild species; the stamen petalody results in increased whorls of petals and generates different flower forms, which are one of the most important traits for cultivar classification. In order to investigate how petaloid stamens are formed, we obtained the coding sequence (666 bp) and genomic DNA sequence of the PsTM6 genes (belongs to B subfamily of MADS-box gene family) from 23 tree peony samples, Five introns and six exons consisted of the genomic DNA sequence. The analysis of cis-acting regulatory elements in the third and fourth intron indicated that they were highly conserved in all samples. Partial putative amino acids were analyzed and the results suggested that functional differentiation of PsTM6 paralogs apparently affected stamen petalody and flower shape formation due to due to amino acid substitution caused by differences in polarity and electronic charge. Sliding window analysis indicated that the different regions of PsTM6 were subjected to different selection forces, especially in the K domain. This is the first attempt to investigate genetic control of the stamen petalody based on the PsTM6 sequence. This will provide a basis for understanding the evolution of PsTM6 and its the function of in determining stamen morphology of tree peony.     

绿盲蝽危害对枣树叶片生化指标的影响

绿盲蝽已在棉区爆发成灾,并逐渐向枣树等北方果树转移危害,已对我国北方果树生产造成严重威胁。绿盲蝽刺吸危害后,能诱导植物产生一系列生化反应。通过生物化学方法研究绿盲蝽不同危害程度对枣树叶片生化指标的影响,探讨受害枣树叶片对绿盲蝽危害的应激反应的变化规律。结果表明,受害枣树叶片内可溶性糖含量随着危害程度的加重先升高,后降低;蛋白质含量随受害程度的加重而呈现降低趋势;游离氨基酸含量随受害程度的加重逐渐升高。受害后枣树叶片内3种防御性酶随受害程度的加重发生不同程度的变化,超氧化物歧化酶(Superoxide Dismutase,SOD)的活性随着危害程度的加重先升高后下降;过氧化物酶(Peroxidase,POD)的活性总体升高;不同受害程度枣树叶片内过氧化氢酶(Catalase,CAT)的活性之间以及它们与未受害枣树叶片内过氧化氢酶(CAT)的活性之间均未达到显著性差异水平。总之,随着绿盲蝽危害程度的加重,枣树叶片内可溶性糖、蛋白质、游离氨基酸含量以及防御性酶活性发生了不同程度的变化,枣树叶片内除过氧化氢酶(CAT)的活性变化外,可溶性糖、游离氨基酸和蛋白质的含量变化以及超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性变化与绿盲蝽危害胁迫有明显的关系,说明枣树叶片对绿盲蝽的危害胁迫产生了应激反应,且叶片内除过氧化氢酶(CAT)外的其他生化指标与绿盲蝽的不同危害程度有一定的相关性。研究结果为理解枣树受绿盲蝽危害后的应激反应机制提供了材料,对绿盲蝽可持续治理具有重要指导意义。     

中国昆明小鼠亚群蛋白质多态性的研究

本文报道采用电泳技术对北京、上海、长春3市的4个中国昆明小鼠(简称KM)实验群体中24个蛋白质标志研究的结果,与我国1981年从美国引进的NIH小鼠进行比较,显示出:(1)KM小鼠亚群间等位基因组成无明显差异,它们间遗传距离为0.008—0.027,与群体封闭时间成正相关;(2)4个KM小鼠群体间聚类分析发现S:KM群体为特殊一类,该结果与KM亚群间下颌骨分析结果相符;(3)KM与Swiss来源的NIH小鼠群体间在E(?)-3、Es-10、Got-2、Glo-1、Gpt-1、和Mpi-1座位上的等位基因组成存在显著差异,它们之间的遗传距离平均值为0.131±0.011,证实中国KM小鼠为非Swiss来源的一个亚种。     

基于微卫星标记的苹果绵蚜种群遗传结构动态

【目的】苹果绵蚜是我国重要的入侵害虫,对苹果生产造成了严重危害。近年来,苹果绵蚜扩散面积增大,危害加重。了解苹果绵蚜入侵过程中的分子生态变化,可为该虫的综合防控提供依据。【方法】利用微卫星标记技术,选择6个微卫星位点对山东省6个地区(烟台、威海、青岛、潍坊、聊城、泰安)2012—2015年苹果绵蚜种群遗传结构变化规律进行分析。【结果】2012—2015年,山东省6个地区的苹果绵蚜遗传多样性随时间推移逐渐降低。其中,2012年的遗传多样性极显著高于2013—2015年;2013—2015年之间虽然差异不显著,但随时间推移,等位基因观测值(Na)和期望杂合度(He)等遗传多样性指数有逐渐降低的趋势。通过无限等位基因模型、双相突变模型和逐步突变模型分析发现,6个地区的苹果绵蚜均经历了瓶颈效应,是遗传多样性降低的主要原因。对6个微卫星位点分析发现,Erio20、Erio75和Erio78扩增到的苹果绵蚜等位基因数量以及这3个位点的多样性指数随时间推移逐渐降低。【结论】Erio20、Erio75和Erio78是引起苹果绵蚜遗传多样性降低的主要多态位点。苹果绵蚜可能进化出了"超级克隆"基因型,因此,其可在我国适应不同生态环境并增大扩散范围。     

Interleukin-33/ST2 signaling promotes production of interleukin-6 and interleukin-8 in systemic inflammation in cigarette smoke-induced chronic obstructive pulmonary disease mice

Interleukin-33 is a newly described member of the interleukin-1 family. Recent research suggests that IL-33 is increased in lungs and plays a critical role in chronic airway inflammation in cigarette smoke-induced chronic obstructive pulmonary disease (COPD) mice. To determine the role of IL-33 in systemic inflammation, we induced COPD mice models by passive cigarette smoking and identified the IL-33 expression in bronchial endothelial cells and peripheral blood mononuclear cells (PBMCs) of them. After isolation, PBMCs were cultured and stimulated in vitro. We measured expressions of interleukin-6 and interleukin-8 in PBMCs in different groups. The expression of IL-33 in bronchial endothelial cells and PBMCs of COPD mice were highly expressed. Stimulated by cigarette smoke extract (CSE), the expression of IL-6 and IL-8 were induced and enhanced by IL-33. PBMCs of COPD mice produced more IL-6 and IL-8 stimulated by CSE and IL-33. Expression of IL-6 and IL-8 were decreased when stimulated by IL-33 together with soluble ST2. The mRNA production of ST2 in IL-33 stimulated PBMCs was increased. Being pretreated with several kinds of MAPK inhibitors, the secretions of IL-6 and IL-8 in PBMCs did not decrease except for the p38 MAPK inhibitor. We found that IL-33 could induce and enhance the expression of IL-6 and IL-8 in PBMCs of COPD mice via p38 MAPK pathway, and it is a promoter of the IL-6 and IL-8 production in systemic inflammation in COPD mice.     

Effect of SpyTag/SpyCatcher cyclization on stability and refolding of green fluorescent protein

Biotechnology Letters - To study the effect of SpyTag/SpyCatcher cyclization on stability and refolding of protein, we constructed a cyclized green fluorescent protein (SRGFP) and its derivative to...     

基于对虾白斑综合症病毒极早期启动子的新型杆状病毒表达载体的构建与分析

摘要：【目的】构建携带有受杆状病毒多角体启动子控制的疱疹性口腔炎病毒糖蛋白(vesicular stomatitis virus glycoprotein, VSV G)和受白斑综合症病毒极早期基因(immediately-early gene 1,ie1)启动子控制的绿色荧光蛋白(enhanced green fluorescent protein, EGFP)两个表达阅读框的新型重组病毒vAc-G-EGFP,分析其在无脊椎动物和脊椎动物细胞系中表达报道基因的能力。【方法】 利用Bac-To-Bac 系统构建重组杆状病毒,利用病毒感染或转导实验介导报道基因在待测细胞系中的表达,用荧光显微镜和免疫印迹技术分析报道基因在待测细胞系中的实时表达情况。 【结果】成功构建了分别含VSV G 和 ie1启动子两个阅读框的重组杆状病毒vAc-G-EGFP,发现vAc-G-EGFP可以在无脊椎和脊椎动物细胞系中有效表达报道基因EGFP,免疫印迹实验显示,在不同时间点EGFP于这两类细胞中的表达存在差异。【结论】 基于白斑综合症病毒ie1启动子并携带有VSV G表达框的单一杆状病毒载体可以实现同时在不同种类细胞系中有效表达外源基因。本文构建的新型杆状病毒表达载体有希望普遍应用于基础和应用生物学研究。