新发现接通了基因组调控的一条逻辑链

生物学一条被勘察了无数次的信号通路可能还藏有不为人知的功能:防止蛋白生产线出现瓶颈效应。大肠杆菌需摄入含碳丰富的养分才能生长,并按照固定的顺序选择碳源。例如,当葡萄糖充足时,它就会停止合成用来运输和分解其他碳源(如乳糖或麦芽糖)的酶。20世纪40年代,剑桥大学生化学家Helen Epps和Ernest Gale观察到此现象,并将它命名为葡萄糖效应。现在知道其他糖类也能触发类似的响应,它们被统称为分解代谢抑制效应。     

第24届国际统计物理大会记事

1 Cairns印象 2010年7月17日搭乘香港往Cairns的国泰午夜航班,安顿下来后,眯上眼睛刚进入梦乡,飞机已开始降落.第一次踏上南半球的土地,学生时代的好奇和兴奋未减,跟前的景色却又一次无情地证明了地球村的有限.Cairns是澳大利亚东北部的一座海滨小镇,清新、安逸、平和、山水相依,天空优雅飞翔的海鸟和海滩上健身慢跑的人影,让人想起加州、地中海或我们山东半岛的一座座海滨城镇.如果不是太阳从东往北逆时针移动,还真不觉得已来到了袋鼠的故乡.     

Sub-diffusive scaling with power-law trapping times

Thermally driven diffusive motion of a particle underlies many physical and biological processes. In the presence of traps and obstacles, the spread of the particle is substantially impeded, leading to subdiffusive scaling at long times.The statistical mechanical treatment of diffusion in a disordered environment is often quite involved. In this short review,we present a simple and unified view of the many quantitative results on anomalous diffusion in the literature, including the scaling of the diffusion front and the mean first-passage time. Various analytic calculations and physical arguments are examined to highlight the role of dimensionality, energy landscape, and rare events in affecting the particle trajectory statistics. The general understanding that emerges will aid the interpretation of relevant experimental and simulation results.     

A computational study of the chemokine receptor CXCR1 bound with interleukin-8

CXCR1 is a G-protein coupled receptor, transducing signals from chemokines, in particular the interleukin-8(IL8)molecules. This study combines homology modeling and molecular dynamics simulation methods to study the structure of CXCR1-IL8 complex. By using CXCR4-v MIP-II crystallography structure as the homologous template, CXCR1-IL8 complex structure was constructed, and then refined using all-atom molecular dynamics simulations. Through extensive simulations, CXCR1-IL8 binding poses were investigated in detail. Furthermore, the role of the N-terminal of CXCR1 receptor was studied by comparing four complex models differing in the N-terminal sequences. The results indicate that the receptor N-terminal affects the binding of IL8 significantly. With a shorter N-terminal domain, the binding of IL8 to CXCR1 becomes unstable. The homology modeling and simulations also reveal the key receptor-ligand residues involved in the electrostatic interactions known to be vital for complex formation.     

Synergistic Effect of Auto-Activation and Small RNA Regulation on Gene Expression

Auto-activation and small ribonucleic acid （RNA）-mediated regulation are two important mechanisms in controlling gene expression. We study the synergistic effect of these two regulations on gene expression. It is found that under this combinatorial regulation, gene expression exhibits bistable behaviors at the transition regime, while each of these two regulations, if working solely, only leads to monostability. Within the stochastic framework, the base pairing strength between sRNA and mRNA plays an important role in controlling the transition time between on and off states. The noise strength of protein number in the off state approaches 1 and is smaller than that in the on state. The noise strength also depends on which parameters, the feedback strength or the synthesis rate of small RNA, are tuned in switching the new insight into gene-regulation mechanism and can be gene expression on and off. Our findings may provide applied in synthetic biology.