游泳力竭对冠脉结扎致大鼠慢性心衰模型的优化

目的: 通过结合力竭运动,优化冠脉结扎造大鼠缺血性慢性心力衰竭（心衰）模型的方法,综合评价模型实效性及稳定性。方法: 成年SD大鼠40只,施冠状动脉结扎术致心肌缺血模型,4周后B超检测左心室射血分数（LVEF）,成模11只为冠脉结扎组（以LVEF<40%为模型建立标准）,>40%的22只大鼠进行1 h/d×15 d的游泳运动,以加大心脏负荷促进心衰的进展,又成模8只大鼠为结扎后力竭组。实验结束后检测心功能指标,脑钠肽（BNP）及心肌组织形态学变化,与10只空白大鼠比较各指标变化。结果: 结扎后力竭组左心室射血分数（LVEF）为（38.70±10.10）%,冠脉结扎组LVEF为（39.20±11.10）%,较Control组（84.60±3.64）%明显降低（P＜0.01）;结扎后力竭组左室舒张末压（LVEDP）为（11.5±1.3） mm Hg,冠脉结扎组LVEDP为（10.68±4.45） mm Hg,较Control组（4.4±0.2） mm Hg显著升高（P＜0.01）;结扎后力竭组血浆BNP水平为(561.0±21.0) μg/L,冠脉结扎组BNP水平为（548.6±25.8） μg/L,较Control组（366.2±21.8） μg/L显著升高（P＜0.01）。Masson染色中,Control组切片纹路清晰且红染的心肌细胞较多,而冠脉结扎组与结扎后力竭组存在大量蓝染的胶原纤维,心肌纤维明显减少成条索状。4周时成模率约为35%,经力竭运动后实验组总成模率升高至约62%,虽冠脉结扎组与结扎后力竭组各指标无统计学差异,但提高成模率效果显著（P＜0.01）。结论: 游泳力竭运动可促进冠状动脉高位结扎致缺血性慢性心衰模型的成功率,成本经济,适合推广。     

Caput Ligation Renders Immature Mouse Sperm Motile and Capable to Undergo cAMP-Dependent Phosphorylation

Mammalian sperm must undergo two post-testicular processes to become fertilization-competent: maturation in the male epididymis and capacitation in the female reproductive tract. While caput epididymal sperm are unable to move and have not yet acquired fertilization potential, sperm in the cauda epididymis have completed their maturation, can move actively, and have gained the ability to undergo capacitation in the female tract or in vitro. Due to the impossibility of mimicking sperm maturation in vitro, the molecular pathways underlying this process remain largely unknown. We aimed to investigate the use of caput epididymal ligation as a tool for the study of sperm maturation in mice. Our results indicate that after seven days of ligation, caput sperm gained motility and underwent molecular changes comparable with those observed for cauda mature sperm. Moreover, ligated caput sperm were able to activate pathways related to sperm capacitation. Despite these changes, ligated caput sperm were unable to fertilize in vitro. Our results suggest that transit through the epididymis is not required for the acquisition of motility and some capacitation-associated signaling but is essential for full epididymal maturation. Caput epididymal ligation is a useful tool for the study of the molecular pathways involved in the acquisition of sperm motility during maturation.     

基于连接酶和磷酸化探针的单碱基突变检测方法研究

该文发展了一种基于表面连接酶反应及生物金属化的电化学方法用于单碱基突变的检测.金电极表面先固定捕获探针,然后和待检测的突变链及5'端磷酸化的连接探针杂交,在连接酶存在下,表面固定的探针会和连接探针连接起来.如果表面固定的探针和目标链不匹配,则连接反应不能进行.在90℃下进行热变性处理,形成的双链解开,进行了连接反应的连接探针连接到了金电极上.接着,生物素化的检测探针和连接产物杂交,再和链亲和素化的碱性磷酸酶反应,在碱性磷酸酶的作用下,非还原性的抗坏血酸磷酸酯(AA-P)转化成还原性的抗坏血酸(AA).溶液中的银离子在抗坏血酸的作用下,被还原生成银,从而使得银颗粒沉积在电极表面.用线性扫描伏安法来检测电极表面沉积的银.该方法已成功的用于检测编码K-Ras癌基因的第12位密码子的单碱基突变,检测下限低达80 fmol/L.     

粉防己碱对血管性痴呆大鼠齿状回S1000B蛋白表达的研究

目的：探讨粉防己碱（Tet）对血管性痴呆（VaD）大鼠齿状回S1000B蛋白表达的影响以及在血管性痴呆发病中的作用。方法：运用双侧颈总动脉永久性结扎（2-VO法）建立VaD大鼠模型,Nissl染色观察海马齿状回（DG）神经元内的尼氏小体的变化,免疫荧光观察海马DG区S100B的表达情况,F1uo-3/AM探针负载后检测各组大鼠海马内〔Ca2＋〕i浓度变化,探讨Tet改善VaD大鼠神经功能的分子机制。结果：Nissl染色后,Tet干预组大鼠海马DG区尼氏小体较模型组显著增多;免疫标记发现Tet干预组大鼠DG区神经元内S100B蛋白的表达量明显增多;Tet干预组大鼠海马〔Ca2＋〕i浓度显著下降（p〈0.05）。结论：Tet可改善大鼠脑缺血损伤引起的学习记忆能力障碍,可能与Tet下调S100B蛋白,抑制钙离子有关。     

用HT_c rf SQUID对动物心肌的受损进行检测

通过对健康兔子进行冠状动脉结扎手术,建立急性心肌梗死的动物模型,使用自行研制的HTcrfSQUID梯度计和常规心电图仪,实施并完成了几例兔子正常心脏和急性心肌梗死心脏的心磁图/心电图测量,这在国内尚属首次。通过对比不同缺血状况下心磁图/心电图随时间的演变行为,发现结扎前后MCG呈现显著变化。     

Protein Spin Labeling with a Photocaged Nitroxide Using Diels–Alder Chemistry

EPR spectroscopy of diamagnetic bio-macromolecules is based on site-directed spin labeling (SDSL). Herein, a novel labeling strategy for proteins is presented. A nitroxide-based spin label has been developed and synthesized that can be ligated to proteins by an inverse-electron-demand Diels–Alder (DA_inv) cycloaddition to genetically encoded noncanonical amino acids. The nitroxide moiety is shielded by a photoremovable protecting group with an attached tetra(ethylene glycol) unit to achieve water solubility. SDSL is demonstrated on two model proteins with the photoactivatable nitroxide for DA_inv reaction (PaNDA) label. The strategy features high reaction rates, combined with high selectivity, and the possibility to deprotect the nitroxide in Escherichia coli lysate.     

A Modular Ligation Strategy for Asymmetric Bivalent Nucleosomes Trimethylated at K36 and K27

In nature, individual histones in the same nucleosome can carry identical (symmetric) or different (asymmetric) post-translational modification (PTM) patterns, increasing the combinatorial complexity. Embryonic stem cells exhibit “bivalent” nucleosomes, some of which are marked by an asymmetric arrangement of H3K36me3 (an activating PTM) and H3K27me3 (a repressive PTM). Here we describe a modular synthetic method to access such asymmetrically modified nucleosomes and show that H3K36me3 inhibits the activity of the methyltransferase PRC2 locally while still prolonging its chromatin binding time.     

Efficient and Chemoselective Surface Immobilization of Proteins by Using Aniline‐Catalyzed Oxime Chemistry

Site‐specific immobilization of peptides and proteins is crucial to ensure their functionality in surface‐based assays. We report the use of aniline‐catalyzed oxime ligations as a very efficient and broadly applicable method to covalently attach the N terminus of proteins and peptides to a surface functionalized with alkoxy‐amine groups.

     

用MM2分子力学研究轴向配体与咕啉之间的相互作用

用分子力学MM2方法,研究了不同轴向配体与咕啉之间的相互作用,分别考察了Co-C键、Co-N键以及Co-S键之间的成键特征,以及考察了第六个轴向配体的配位作用对第五个轴向配体所产生的影响。同时,也讨论了MM2方法在该研究中的优缺点。