Trypsin inhibitory loop is an excellent lead structure to design serine protease inhibitors and antimicrobial peptides

The disulfide-bridged hendecapeptide ( CWTKSIPPKPC) loop, derived from an amphibian skin peptide, is found to have strong trypsin inhibitory capability. This loop, called the trypsin inhibitory loop ( TIL), appears to be the smallest serine protease inhib

云南保山猪线粒体DNA D loop区序列初步分析

为了解云南保山猪(Baoshan pig)的遗传多样性及其遗传背景，我们测定了19个个体线粒体DNA Dloop高变区1 1 5 363 - 1 5 801片段序列438帅。检测到1。种单倍型，包括8个多态位点，其中5次T/ C转换、1次G/ A转换、1次G/ C颠换和1次A/ T颠换，其A.T.GX碱基的平均含量分别为35.4%.26.9%.13.2%和24.5 %,A+ T含量(62 .3)明显高于G+ C含量(37 .7 %)。对于保山猪的保种及其持续利用有着重要的理论指导意义。

Genetic diversity and origin of Chinese cattle revealed by mtDNA D-loop sequence variation

To determine the origin and genetic diversity of Chinese cattle, we analyzed the complete mtDNA D-loop sequences of 84 cattle from 14 breeds/populations from southwest and west China, together with the available cattle sequences in GenBank. Our results sh

Dynamics of RNA with A6 bulge loop

In order to understand the behavior of RNAs with large bulges In solution, molecular dynamics was performed on the RNA molecule in water with A6 bulge. The result of simulation showed that nonstacked conformation Is the main conformation in large bulges, and the backbone of large bulge is of great conformational flexibility, but bulges-induced bends are relatively rigid. The fluctuation in bulge has little influence on the bend angle of RNAs.

Statistical correlation between protein secondary structure and messenger RNA stem-loop structure

Anew integrated sequence-structure database, called IADE (Integrated ASTRAL-DSSP-EMBL), incorporating matching mRNA sequence, amino acid sequence, and protein secondary structural data, is constructed. It includes 648 protein domains. Based on the IADE database, we studied the relation between RNA stem-loop frequencies and protein secondary structure. It was found that the alpha-helices and beta-strands on proteins tend to be preferably "coded" by mRNA stem region, while the coils on proteins tend to be preferably "coded" by mRNA loop region. These tendencies are more obvious if we observe the structural words (SWs). An SW is defined by a four-amino-acid-fragment that shows the pronounced secondary structural (alpha-helix or beta-strand) propensity. It is demonstrated that the deduced correlation between protein and mRNA structure can hardly be explained as the stochastic fluctuation effect. (C) 2003 Wiley Periodicals, Inc.

线粒体D-loop序列变异与东方鲀属鱼类系统发育

东方鲀属的红鳍东方鲀(Takifugu rubripes)是后基因组时代的一种重要模式生物。本研究中,利用东方鲀属11种鱼类(18尾)的D-loop基因序列,对东方鲀属鱼类的系统发育关系进行研究。经序列比对排定后,分析中D-loop序列有841个位点,其中395个位点为可变位点,267个位点为系统发育信息位点。分别采用邻接法(NJ)、最大简约法(MP)、最大似然法(ML)和贝叶斯方法构建了分子系统树。研究结果表明:(1)东方鲀属鱼类为一单系类群;(2)由横纹东方鲀(T. oblongus)和铅点东方鲀(T

线粒体DNA d-loop序列变异与鳅鮀亚科鱼类系统发育

对鳅鮀亚科(Gobiobotinae)2个属8个种10个个体线粒体控制区d-loop全序列进行了测定.以(鱼丹)亚科斑马鱼为外类群,对鳅鮀及鲤科(Cyprinidae)一些亚科代表种鱼类进行了系统发育分析.结果显示,鳅鮀鱼类是一个单系类群,与鮈和细鲫有较近的亲缘关系.从系统发育的角度看,鳅鮀亚科应归属于鮈亚科(Gobioninae).研究结果支持鳅鮀亚科分为异鳔鳅鳅属(Xenophyso-gobio)和鳅鮀属(Gobiobtia).

Mitochondrial d-loop sequence variation and phylogeny of gobiobotine fishes

The mitochondrial DNA control region is amplified and sequenced from 8 genera and 10 species of gobiobotine fishes. The phylogenetic tree of Gobiobotinae and some representative species of other Cyprinid subfamilies obtained by the method of neighborhood joining, maximum likelihood and maximum parsimony with Danio rerio as an outgroup indicates that Gobiobotinae fishes are a monophyletic group which is close to Gobioninae subfamily. Gobiobotinae should be included into subfamily Gobioninae in terms of phylogenetic analysis. The research result supports that Gobiobotinae can be divided into genus Xenophysogobio and Gobiobotia. Xenophysogabio is the most primitive genera in the subfamily.

Degenerate four-wave mixing based all-optical wavelength conversion in a semiconductor optical amplifier and highly-nonlinear photonic crystal fiber parametric loop mirror

The idler is separated from the co-propagating pump in a degenerate four-wave mixing (DFWM) with a symmetrical parametric loop mirror (PALM), which is composed of two identical SOAs and a 70 m highly-nonlinear photonic crystal fiber (HN-PCF). The signal and pump are coupled into the symmetrical PALM from different ports, respectively. After the DFWM based wavelength conversion (WC) in the clockwise and anticlockwise, the idler exits from the signal port, while the pump outputs from its input port. Therefore, the pump is effectively suppressed in the idler channel without a high-speed tunable filter. Contrast to a traditional PALM, the DFWM based conversion efficiency is increased greatly, and the functions of the amplification and the WC are integrated in the smart SOA and HN-PCF PALM. (C) 2008 Elsevier B.V. All rights reserved.

Pump-Suppressed Nondegenerate Four-Wave Mixing in a Highly Nonlinear Photonic Crystal Fiber Sagnac Loop

We propose a configuration for suppressing pumps in a broad- and flat-hand tunable nondegenerate four-wave mixing (FWM) wavelength converter. The signal and pumps are coupled into a highly nonlinear photonic crystal fiber symmetrical Sagnac loop. After the FWM wavelength conversion in the loop, the idler is separated from the pumps without a filter. In our experiment, a flat wavelength conversion bandwidth of 36 rim, conversion efficiency of-11 dB., pump-to-signal suppression ratio of 48 dB, and idler-to-pump suppression ratio of 15 dB are achieved.

A novel hybrid phase-locked-loop frequency synthesizer using single-electron devices and CMOS transistors

This paper proposes a novel phase-locked loop (PLL) frequency synthesizer using single-electron devices (SEDs) and metal-oxide-semiconductor (MOS) field-effect transistors. The PLL frequency synthesizer mainly consists of a single-electron transistor (SET)/MOS hybrid voltage-controlled oscillator circuit, a single-electron (SE) turnstile/MOS hybrid phase-frequency detector (PFD) circuit and a SE turnstile/MOS hybrid frequency divider. The phase-frequency detection and frequency-division functions are realized by manipulating the single electrons. We propose a SPICE model to describe the behavior of the MOSFET-based SE turnstile. The authors simulate the performance of the PILL block circuits and the whole PLL synthesizer. Simulation results indicated that the circuit can well perform the operation of the PLL frequency synthesizer at room temperature. The PILL synthesizer is very compact. The total number of the transistors is less than 50. The power dissipation of the proposed PLL circuit is less than 3 uW. The authors discuss the effect of fabrication tolerance, the effect of background charge and the SE transfer accuracy on the performance of the PLL circuit. A technique to compensate parameter dispersions of SEDs is proposed.

A novel fast lock-in phase-locked loop frequency synthesizer with direct frequency presetting circuit

This paper proposes a novel, fast lock-in, phase-locked loop (PLL) frequency synthesizer. The synthesizer includes a novel mixed-signal voltage-controlled oscillator (VCO) with a direct frequency presetting circuit. The frequency presetting circuit can greatly speed up the lock-in process by accurately the presetting oscillation frequency of the VCO. We fully integrated the synthesizer in standard 0.35 mu m, 3.3 V complementary metal-oxide-semiconductors (CMOS) process. The entire chip area is only 0.4 mm(2). The measured results demonstrate that the synthesizer can speed up the lock-in process significantly and the lock-in time is less than 10 mu s over the entire oscillation frequency range. The measured phase noise of the synthesizer is -85 dBc/Hz at 10 kHz offset. The synthesizer avoids the tradeoff between the lock-in speed and the phase noise/spurs. The synthesizer monitors the chip temperature and automatically compensates for the variation in frequency with temperature.