20171006 生命科学领域三篇文献updates:眼泪发电:光

1Applied Physics Letters:科学家利用眼泪实现发电

近日爱尔兰利默克里大学的研究团队,首次证实对人类眼泪中的溶菌酶施压,也可达到发电效果.

据悉,参与研究的索利马尼教授表示:\"我们是第一支团队使用溶菌酶晶体证实压电效应的存在.\"报道称,人类的泪液与鸡蛋的蛋白一样,蕴含大量蛋白质,研究团队发现当眼泪中的\"溶菌酶\"晶体受压时,会产生一种名为\"压电效应\"的化学反应,并可把溶菌酶化成电力.团队相信,日后可把技术应用于收集能量和生物医药等范畴.

研究负责人赛尔德教授说:\"利用晶体是检测压电效应的黄金定律.\"这次研究结果刊登于科学学术杂志《应用物理信件》.

ABSTRACT

Here, we present experimental evidence of the direct piezoelectric effect in the globular protein, lysozyme. Piezoelectric materials are employed in many actuating and sensing applications because they can convert mechanical energy into electrical energy and vice versa. Although originally studied in inorganic materials, several biological materials including amino acids and bone, also exhibit piezoelectricity. The exact mechanisms supporting biological piezoelectricity are not known, nor is it known whether biological piezoelectricity conforms strictly to the criteria of classical piezoelectricity. The observation of piezoelectricity in protein crystals presented here links biological piezoelectricity with the classical theory of piezoelectricity. We quantify the direct piezoelectric effect in monoclinic and tetragonal aggregate films of lysozyme using conventional techniques based on the Berlincourt Method. The largest piezoelectric effect measured in a crystalline aggregate film of lysozyme was approximately 6.5?pC?N?1.These findings raise fundamental questions as to the possible physiological significance of piezoelectricity in lysozyme and the potential for technical applications.

2Science Advances: 光遗传学新工具--新型质子起动机

Liu Jie,Huang Juan,Guo Huan et al. The conserved and unique genetic architecture of kernel size and weight in maize and rice.[J] .Plant Physiol., 2017.

光遗传学(Optogenetics)是一门较新的技术,运用光控制活体组织神经元或肌肉细胞,在神经科学研究领域具有广泛应用.这种方法极为精确,能通过开启或关闭特定的信息传递通路控制单个神经元.类似的,亦可用于部分逆转视力或听力,以及控制肌肉收缩.

作为光遗传学的主要工具,光敏蛋白,被编辑插入细胞后会附着在细胞表面,当暴露在光线之下时将离子跨细胞膜移动.因此,一个改造后的神经元细胞的神经信号可被某个特定光脉冲激活或抑制,这取决于所使用的光敏蛋白.

来自德国尤里希研究中心团队描述了一个名叫NsXeR的新蛋白工具,它属于异视紫红质(xenorhodopsin)类.光暴露下,能激活单个神经元,使其向神经系统发出信号.同理,也能激活肌细胞.

因为受离子浓度变化影响,为了激活细胞,最好阻断钙离子运输.但是当蛋白非选择性地输送各种正离子(如Ca2+)时,可能出现不良副作用.

这种新发现的蛋白能避免失控的钙离子运输:它是选择性的,只泵质子(H+)进入细胞.由于这种选择性,相比它的主要竞争对手\"光敏通道蛋白(channelrhodopsin)\"不能区分正离子的特点,它具有相当大的优势.一个正电荷离子进入一个兴奋的细胞,会让内外膜之间的表面张力减小.膜的去极化导致一个神经或肌肉冲动.如果只泵入质子,在引起冲动的同时还可以减少其他副作用.

此外,异视紫红质不依赖离子浓度,能可靠地把质子泵入或泵出细胞.而光敏通道蛋白只允许离子从高浓度向低浓度方向运输.

\"目前我们已经掌握了该蛋白质如何工作的所有必要数据,这会成为我们优化改造光遗传学技术蛋白质工具参数的基础,\"第一作者高级研究员Vitaly Shevchenko说.

Abstract

Generation of an electrochemical proton gradient is the first step of cell bioenergetics. In prokaryotes, the gradient is created by outward membrane protein proton pumps. Inward plasma membrane native proton pumps are yet unknown. We describe comprehensive functional studies of the representatives of the yet noncharacterized xenorhodopsins from Nanohaloarchaea family of microbial rhodopsins. They are inward proton pumps as we demonstrate in model membrane systems, Escherichia coli cells, human embryonic kidney cells, neuroblastoma cells, and rat hippocampal neuronal cells. We also solved the structure of a xenorhodopsin from the nanohalosarchaeon Nanosalina (NsXeR) and suggest a mechanism of inward proton pumping. We demonstrate that the NsXeR is a powerful pump, which is able to elicit action potentials in rat hippocampal neuronal cells up to their maximal intrinsic firing frequency. Hence, inwardly directed proton pumps are suitable for light-induced remote control of neurons, and they are an alternative to the well-known cation-selective channelrhodopsins.

文章来源：《生命科学》 网址: http://www.smkxzz.cn/zonghexinwen/2020/1028/485.html