The Modular Of Biological Network And Its Dynamics

The fundamental goal of biology is to understand every details and mecha-nism in biological system, while that of systems biology is to study the interactionand relationship between the subsystem and biological system. Systems biologyis an emerging interdisciplinary subject involving biology, mathematics and com-puter and so on.Chapter 1 is an introduction of the background of this paper and containthe basic material for later use. The origin and development of systems biologyare firstly introduced in this part, then the characteristics of this subject is ex-pounded in detail. It's very important to understand systems biology on howto study it, therefore, the methods of studying this subject have been given inthis paper. Coding and non-coding RNAs play important roles in gene regulationnetworks, so the mechanism of gene, esp sRNA, are elaborated carefully in Chap-ter 1. Biological networks consist of many modular or motifs, so it's necessaryto investigate the properties of these motifs. The research approach about themotifs is given in detail in this paper, for instance, dynamics and approximationmethod and so on. At last, several coupled feedback loops are elucidated in thischapter.Chapter 2 is a study on signal transduction and noise filtering in biologi-cal network. Many interacting biomolecular components in cells form differentpositive or negative feedback loops. When biological signals transduce throughcascades consisting of various loops they will be affected or even distorted. Es-pecially, how to process various signals buried in various intrinsic and extrinsicnoises is an important issue. This paper analyzes how the response time influ-ences noise filtering ability and how to enhance the ability by coupling differentfeedback loops. A parameter to measure the response time of the signal transduc-tion, i.e.,Ï„0.9, and its relationship between the response time and noise filtering will be discussed. The authors show clearly that the longer the response time is,the better the ability to filter noises will be. Therefore, to enhance the abilityto filter noises, the authors can prolong the response time by coupling differentpositive or negative feedback loops. The results provide a possible approach toenhance the ability to filter noises in larger biomolecular networks.Chapter 3 focuses on the study of regulation network of sRNA in gene net-works. The interplay of small noncoding RNAs (sRNAs), mRNAs, and proteinshas been shown to play crucial roles in almost all cellular processes. As key post-transcriptional regulators of gene expression, the mechanisms and roles of sRNAsin various cellular processes still need to be fully understood. When participatingin cellular processes, sRNAs mainly mediate mRNA degradation or translationalrepression. Here, we show how the dynamics of two minimal architectures is dras-tically affected by these two mechanisms. A comparison is also given to reveal theimplication of the fundamental differences. This study may help us to analyzecomplex networks assembled by simple modules more easily. A better knowledgeof the sRNA-mediated motifs is also of interest for bio-engineering and artificialcontrol.