Genetic and molecular approaches to synthesis and action of the yeast killer toxin

Summary The K1 killer toxin ofSaccharomyces cerevisiae is a secreted, virally-coded protein lethal to sensitive yeasts. Killer yeasts are immune to the toxin they produce. This killer system has been extensively examined from genetic and molecular perspectives. Here we review the biology of killer yeasts, and examine the synthesis and action of the protein toxin and the immunity component. We summarise the structure of the toxin precursor gene and its protein products, outline the proteolytic processing of the toxin subunits from the precursor, and their passage through the yeast secretory pathway. We then discuss the mode of action of the toxin, its lectin-like interaction with a cell wall glucan, and its probable role in forming channels in the yeast plasma membrane. In addition we describe models of how a toxin precursor species functions as the immunity component, probably by interfering with channel formation. We conclude with a review of the functional domains of the toxin structural gene as determined by site-directed mutagenesis. This work has identified regions associated with glucan binding, toxin activity, and immunity.     

PPARδ inhibits IL-1β-stimulated proliferation and migration of vascular smooth muscle cells via up-regulation of IL-1Ra

Activation of peroxisome proliferator-activated receptor (PPAR) δ by GW501516, a specific PPARδ ligand, significantly inhibited interleukin (IL)-1β-induced proliferation and migration of vascular smooth muscle cells (VSMCs). This effect of GW501516 was dependent on transforming growth factor-β, and was mediated through the up-regulation of IL-1 receptor antagonist. The inhibitory effect of GW501516 on VSMC proliferation was associated with cell cycle arrest at the G1 to S phase transition, which was accompanied by the induction of p21 and p53 along with decreased cyclin-dependent kinase 4 expression. Inhibition of cell migration by GW501516 was associated with the down-regulation of matrix metalloproteinase (MMP)-2 and MMP-9 in IL-1β-treated VSMCs. Inhibition of extracellular signal-regulated kinase significantly reduced the GW501516-mediated inhibition of IL-1β-stimulated VSMC proliferation. These results suggest that PPARδ plays an important role in the pathophysiology of diseases associated with the proliferation and migration of VSMCs.     

分数阶Fourier域多通道采样的滤波器组高效实现

研究了分数阶Fourier域周期非均匀采样以及多通道采样的滤波器组高效插值和重建方法．首先，根据分数阶Fourier变换的性质，得到了分数阶Fourier域插值和采样的恒等结构；然后根据该恒等结构，得到了从分数阶Fourier域多通道采样和周期非均匀采样中重建原始信号的滤波器组高效实现方法；最后建立了分数阶Fourier域多通道采样和分数阶Fourier域滤波器组的关系，并进一步说明可以通过分数阶Fourier域准确重建滤波器组，导出分数阶Fourier域新的采样和重建策略．     

Investigations of ZnO thin films deposited by a reactive pulsed laser ablation

Highly transparent ZnO thin films were deposited at different substrate temperatures by pulsed laser deposition in an oxygen atmosphere.The thin films were characterized by various techniques including X-ray diffraction,scanning electron microscopy,optical absorption,and photoluminescence.We demonstrated that oriented wurtzite ZnO thin films could be deposited at room temperature using a high purity zinc target.Variable temperature photoluminescence revealed new characteristics in the band edge emission.The...     

Novel Elastomeric Fabrics for the Treatment of Hypertrophic Burn Scars Using Polyhexamethylene Biguanide Antimicrobial Agents

In burn treatments,microorganisms on pressure garments during pressure therapy can prevent rehabilitation by causing functional,hygienic,and aesthetic difficulties. As bacterium is one of the most trouble-causing organisms,they can threaten patients causing infection during the long period of use of these garments.Novel burn pressure garments having durable antimicrobial property were developed using polyhexamethylene biguanide( PHMB)antimicrobial agent procedure on highly elastic nylon 66 /spandex fabrics in powernet,flat warp and weft knitted structures using paddry-cure method. Commercial wireless pressure sensors were used to control pressures at an acceptable medical range. Antimicrobial activity,wash durability,Fourier transform infrared spectroscopy(FTIR) and Scanning electron microscopy(SEM) analyses were conducted for the treated samples. Antimicrobial test results following AATCC 100 Test Method showed 99% reduction of bacteria for the fabric samples treated with PHMB. A small but significant decrease in antimicrobial activity was observed even after50 launderings. These treatments also yield good results to prevent odor,decrease infection by preventing and /or blocking microbial growth according to the antimicrobial mechanism and support reducing of scarring by providing a hygienic environment around the scar.     

A family study of endophenotypes for psychosis within an early intervention programme in Hong Kong: Rationale and preliminary findings

The study of endophenotypes may be a viable strategy to tackle the genetic complexity and phenotypic heterogeneity of psychosis, but this research direction is relatively under-developed in China as compared to Western countries. We have recently initiated one of the first family studies of endophenotypes for psychosis in China. Patients entering an established early psychosis intervention service are recruited into this research project for phenotyping, endophenotyping and genotyping. At the endophenotypic...     

A hybrid-stress solid-shell element for non-linear analysis of piezoelectric structures

This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures.To subdue shear,trapezoidal and thickness locking,the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed.With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement,an extended Hellinger-Reissner functional can be derived.By choosing the ass...