重组人胸腺肽α1在大肠杆菌中的表达纯化和鉴定

用PCR将化学合成的人胸腺肽α1基因扩增并克隆到pMD18-T载体中,经过KpnI／SacI酶切、连接将胸腺肽基因插入到表达载体pET32b中硫氧还蛋白下游．将重组质粒转化至表达宿主BL21(DE3)中,经IPTG诱导,Zn—Sepharose亲和层析纯化以及复性处理,从每升菌液中可获得35mg硫氧还蛋白-胸腺肽α1融合蛋白．经凝血因子Xa酶切、Zn—Sepharose亲和层析以及反相高效液相色谱纯化获得3．8mg重组人胸腺肽．小鼠胸腺细胞凋亡实验表明,重组人胸腺肽能显地抑制地赛米松诱导的小鼠胸腺细胞的凋亡,且该抑制作用与重组人胸腺肽的浓度呈剂量依赖关系．     

Involvement of penaeidins in defense reactions of the shrimp Litopenaeus stylirostris to a pathogenic vibrio

The present study reports for the first time the involvement of an antimicrobial peptide in the defense reactions of a shrimp infected by a pathogenic Vibrio, Vibrio penaeicida. New members of the penaeidin family were characterized in the shrimp Litopenaeus stylirostris by RT-PCR and RACE-PCR from hemocyte total RNAs, and by mass spectrometry detection and immunolocalization of mature peptides in shrimp hemocytes. In infected shrimps, bacteria and penaeidin distribution colocalized in the gills and the lymphoid organ that represented the main infected sites. Moreover, the shrimp immune response to infection involved massive hemocyte recruitment to infection sites where released penaeidin may participate in the isolation and elimination of the bacteria, We show that the ability of the shrimps to circumvent shrimp infections is closely related to a recovery phase based on the hematopoietic process.Received 25 November 2003; received after revision 8 January 2004; accepted 21 January 2004     

Hemokinins and endokinins

The mammalian tachykinins are a family of peptides that, until recently, has included substance P (SP), neurokinin A and neurokinin B. Since, the discovery of a third preprotachykinin gene (TAC4), the number of tachykinins has more than doubled to reveal several species-divergent peptides. This group includes hemokinin-1 (HK-1) in mouse and rat, endokinin-1 (EK-1) in rabbit, and EKA, EKB, human HK-1 (hHK-1) and hHK(4–11) in humans. Each exhibits a remarkable selectivity and potency for the tachykinin NK₁ receptor similar to SP. Their peripheral expression has led to the proposal that they are the endogenous peripheral SP-like endocrine/paracrine agonists where SP is not expressed. Moreover, their strong cross-reactivity with a specific SP antibody leads us to question many of the proposed locations and roles of SP in the periphery. Additionally, three orphan tachykinin gene-related peptides are identified on TAC4, in rabbit, EK-2 and in humans, EKC and EKD.Received 25 January 2004; received after revision 18 February 2004; accepted 27 February 2004     

Respective roles of short-and long-range interactions in protein folding

A new method was presented to discuss the respective roles of short- and long-range interactions in protein folding. It‘s based on an off-lattice model, which is also being called as toy model. Simulated annealing algorithm was used to search its native conformation. When it is applied to analysis proteins lagt and laho, we find that helical segment catmot fold into native conformation without the influence of long-range interactions. That‘s to say that long-range interactions are the main determinants in protein folding.     

4-Hydroxynonenal-modified amyloid-beta peptide inhibits the proteasome: possible importance in Alzheimer's disease

The amyloid β-peptide (Aβ) is a 4-kDa species derived from the amyloid precursor protein, which accumulates in the brains of patients with Alzheimer’s disease. Although we lack full understanding of the etiology and pathogenesis of selective neuron death, considerable data do imply roles for both the toxic Aβ and increased oxidative stress. Another significant observation is the accumulation of abnormal, ubiquitin-conjugated proteins in affected neurons, suggesting dysfunction of the proteasome proteolytic system in these cells. Recent reports have indicated that Aβ can bind and inhibit the proteasome, the major cytoslic protease for degrading damaged and ubiquitin-conjugated proteins. Earlier results from our laboratory showed that moderately oxidized proteins are preferentially recognized and degraded by the proteasome; however, severely oxidized proteins cannot be easily degraded and, instead, inhibit the proteasome. We hypothesized that oxidatively modified Aβ might have a stronger (or weaker) inhibitory effect on the proteasome than does native Aβ. We therefore also investigated the proteasome inhibitory action of Aβ _1–40 (a peptide comprising the first 40 residues of Aβ) modified by the intracellular oxidant hydrogen peroxide, and by the lipid peroxidation product 4-hydroxynonenal (HNE). H₂O₂ modification of Aβ _1–40 generates a progressively poorer inhibitor of the purified human 20S proteasome. In contrast, HNE modification of Aβ _1–40 generates a progressively more selective and efficient inhibitor of the degradation of fluorogenic peptides and oxidized protein substrates by human 20S proteasome. This interaction may contribute to certain pathological manifestations of Alzheimer’s disease Received 26 September 2000; accepted 26 September 2000     

The use of monthly indicators to forecast quarterly GDP in the short run: an application to the G7 countries

The delayed release of the National Account data for GDP is an impediment to the early understanding of the economic situation. In the short run, this information gap may be at least partially eliminated by bridge models (BM) which exploit the information content of timely updated monthly indicators. In this paper we examine the forecasting ability of BM for GDP growth in the G7 countries and compare their performance to that of univariate and multivariate statistical benchmark models. We run four alternative one‐quarter‐ahead forecasting experiments to assess BM performance in situations as close as possible to the actual forecasting activity. BM are estimated for GDP both for single countries (USA, Japan, Germany, France, UK, Italy and Canada), and area‐wide (G7, European Union, and Euro area). BM forecasting ability is always superior to that of benchmark models, provided that at least some monthly indicator data are available over the forecasting horizon. Copyright © 2007 John Wiley & Sons, Ltd.     

动物抗菌肽的研究及应用

抗菌肽是具有抗菌活性的一类短肽,广泛存在于生物界.研究表明,除了具有广谱抗菌活性外,抗菌肽还具有抗病毒、抗真菌、抗寄生虫及抗肿瘤等生物活性.基于对抗菌肽的分类与特性、结构与活性、作用机理等方面进行系统的分析,综述了抗菌肽研究进展及应用前景.     

无人值守设备远程无线监测系统设计

阐述了以GSM网络为平台,利用SMS短消息技术实现对无人值守设备的远程无线监测.同时,提出了一种以Internet网络为依托,实现WEB网页数据发布的通信模式.介绍了系统组成、结构设计及其软硬件实现.其设计方法具有一定的通用性和先进性,可广泛应用于各领域的无人监测系统中.     

基于单位阵的循环移位构造LDPC码的研究

高码率LDPC码的性能研究正日益受到信道编码界的关注，在许多带宽受限的信道环境下提高码率是提高信息传输速率的有效途径之一．这里通过对基于单位阵的循环移位矩阵构造LDPC码方法的研究，从理论上系统分析了此种构造方法．仿真结果表明，该LDPC码的构造方法能有效规避指定长度环，并在高码率下具有很好的编译码性能．     

Study on peptide-peptide interaction using high-performance affinity chromatography and quartz crystal microbalance biosensor

The specific interaction between sense and antisense peptides was studied by high-performance affinity chromatography （HPAC） and quartz crystal microbalance （QCM） biosensor. Fragment 1-14 of human interferon-β （hlFN-βwas chosen as sense peptide and its three antisense peptides （AS-IFN 1, AS-IFN 2, and AS-IFN 3） were designed according to the degeneracy of genetic codes. The affinity column was prepared with sense peptide as ligand and the affinity chromatographic behavior was evaluated. Glu-substituted antisense peptide （AS-IFN 3） showed the strongest binding to immobilized sense peptide at pH 7.5. A quartz crystal microbalance-flow injection analysis （QCM-FIA） system was introduced to investigate the recognition process in real-time. The equilibrium dissociation constants between sense peptide and AS-IFN 1, AS-IFN 2 and AS-IFN 3 measured 2.08×10^-4, 1.31×10^-4 and 2.22×10^-5 mol/L, respectively. The mechanism study indicated that the specific recognition between sense peptide and AS-IFN 3 was due to sequence-dependent and multi-modal affinity interaction.