Expression of a Shrimp Kunitz-type Protease Inhibitor in Pichia pastoris and Activity Analysis

SKPI(shrimp Kunitz-type protease inhibitor)是日本囊对虾(Marsupenaeus japonicus)体内的一个小分子多肽,含有一个Kunitz型结构域,属于丝氨酸蛋白酶抑制剂。目前已知丝氨酸蛋白酶抑制剂在节肢动物免疫系统中起着非常重要的作用,为了了解SKPI在对虾天然免疫系统中的作用,首先对其进行了重组表达。从日本囊对虾肝胰腺中扩增skpi的cDNA片段,插入改造后的pPIC9K酵母表达载体,获得的重组质粒转化至毕赤酵母GS115进行表达。由于改造的pPIC9K载体加入了6-His标签,因此利用Ni Sepharose High Performance对SKPI进行了高效纯化。初步的活性研究表明,重组表达的SKPI能特异性地抑制胰蛋白酶的水解活性。SKPI(shrimp Kunitz-type protease inhibitor) from Marsupenaeus japonicus is a member of serine protease inhibitors which play an important role in the arthropod immunity.To fully understand its function in the innate immunity of shrimp,the skpi gene was cloned into a modified pPIC9K vector with a 6-His tag and expressed by Pichia pastoris GS115.The secretory SKPI was purified from the medium with high purity by using Ni Sepharose High Performance.This results also indicated that the purified SKPI could inhibit the activity of trypsin specifically.国家高技术研究与发展计划项目(No.2006AA100311);; 福建处科技厅资助重点项目(No.2006N0039)~

Single-walled carbon nanotube embedded porous carbon nanofiber with enhanced electrochemical capacitive performance

Active carbon nanofibers (CNFs) with porous structure show highly electrochemical double-layer capacitance for supercapacitors because of their large specific area. However, their poor crystallization induced the low conductivity, which could largely limit the electrochemical performance of the porous CNFs. In this research, porous CNFs with single-walled carbon nanotubes (SWCNTs) were prepared by electrospinning and high temperature carbonization. The introduction of SWCNTs into porous CNFs could largely enhance the conductivity of the porous CNF nanotextiles, thus the electrochemical performance of the composite nanotextile was largely enhanced. The specific capacitance of the composite could achieve 417 F/g at a current density of 0.5 A/g, and keep 193 F/g at the high current density of 10 A/g. Furthermore its specific capacitance could keep 96% after 2000 cycles of charge/discharge at the current density of 10 A/g. This nanotextile could be a promising candidate for the binder-free and filler-free electrodes of high-performance supercapacitors. (C) 2015 Elsevier B.V. All rights reserved

Rational control on floating catalysts for the growth of carbon nanotube assemblies: From vertically aligned carbon nanotube arrays to carbon nanotube films

Floating catalyst chemical vapor deposition (FCCVD) has been widely used for the growth of various carbon nanotube (CNT) macrostructures, mainly including vertically aligned CNT (VACNT) arrays and none-woven CNT films. However, it is still unclear for the reason why these CNT macrostructures with largely different morphologies were received via the similar method. In this research, it revealed that the growth temperature largely affected the nucleation status of floating catalysts and thus controlled the morphologies of CNT macrostructures from VACNT arrays to none-woven CNT films. In low temperatures (below 800 degrees C), VACNTs were grown by bottom-up mechanism with several CNTs, but not one individual from bottom to up along the array height direction. Furthermore, VACNT arrays were only grown on some substrates that can induce iron atoms aggregating to catalyst particles with a suitable size. When increasing the growth temperature higher than 800 degrees C, more catalyst particles were nucleated in the gas flow, which induced the formation of none-woven CNT films composed of thin CNTs (single-walled CNTs and double-walled CNTs). This research was significative for understanding CNT growth mechanism via FCCVD process and the synthesis of different CNT macrostructures by this strategy. (C) 2015 Elsevier B.V. All rights reserved

Carbon Nanotube/Graphene Hybrid Nanostructures and Their Application in Supercapacitors

In this paper, we review the preparation methods of carbon nanotube (CNT)/graphene composite materials for the electrode of supercapacitors, and introduce the developments of CNT/graphene/pseudocapacitive material ternary composite materials with highly electrochemical performance. The rational designed CNT/graphene composite nanostructures could largely utilize the characteristics of carbon nanomaterials for electrochemical double-large supercapacitors, such as large specific area, high conductivity and befitting porous structure, and also achieve large mass loading of pseudo-capacitive materials with high dispersion for pseudocapacitors. As a result, these composite materials are promising candidates for the electrode materials of high-performance supercapacitors with high capacitance, excellent rate performance and long lifetime

Facile synthesis and characterization of Au-Cu, Pt-Cu nanotubes by sacrificial template method

Bimetallic nanotubes with noble metals have already shown more versatile performances than single-metallic nanotubes. However, most of the current methods to prepare bimetallic nanotubes are based on existed hard template, which could not be easily removed after the formation of bimetallic nanotubes. It is still a challenge for synthesizing bimetallic nanotubes without the template removing subsequently. In this research, we developed a novel method to prepare noble metal-copper (Cu) bimetallic nanotubes with Cu nanowires as the sacrificial template. The aqueous solutions with chloroauric acid or palladium chloride were used to bring displacement reaction with Cu nanowires. The simultaneous alloying effect and Kirkendall effect result in hollow nanostructures. The Cu nanowire was converted to a bimetallic hollow with Au-Cu or Pt-Cu alloy nanotubes. This facile method could achieve large-scale preparation of bimetallic nanotubes with noble metals. Furthermore, this alloy nanotube shows superior electrochemical catalytic performance than single-metallic nanoparticles. (C) 2014 Elsevier Ltd. All rights reserved