Research On The Structure And Function Of Complex Biology Networks Form The Perspective Of The Graph And Cybernetics Theories

Despite much effort,identification of complex molecular network structures and study of their organizing and functional roles remain a formidable challenge in systems biology,which however is essential in reaching a systematic understanding of large-scale cell regulation networks and hence gaining capacity of exerting effective interference to cell activity.The past decade witnessed much progress on analyzing structures and dynamics of complex biological systems.Topology analysis may capture the property of the whole network.But this type of analysis is purely based on the network structures and may not be able to dynamically sense the variation due to the change between two basic elements.Conversely,deterministic computation concentrate on the investigation of dynamics of given networks.However,the estimation of kinetic parameter and incurred computational load severely limits our ability for performing detailed analysis.For all these reasons more effective analysis toolkits are called for.Combining control and graph theoretic methods,we proposed an algorithm to collect all the paths belonging to the forward module and extract feedbacks from the rest of a cell signaling networks.We successfully retrieved one signaling forward module and hierarchical feedback modules of three important signaling networks.We found that global and local feedbacks act in very different ways and on distinct features of the information flow conveyed by signal transduction but work highly coordinately to implement specific biological functions.Combination of the three networks structural and dynamical characteristics,we put forward an abstract model of cell signal transduction.It can not only effectively evolution,but also can reasonably explain how cells transmit signals quickly from the input to output in a controlled manner.The redundancy embodied with multiple signal-relaying channels and feedback controls bestow great robustness.While system dynamics is the sensitive to the parameters correlated with reaction hubs and the deletion of local feedbacks embodying the systematic fragility.However,the boundary between robustness and fragility is blured by Survival of the fittest since they are in unity under evolution.The current investigation reveals intriguing general features of the organization of cell signaling networks and their relevance to biological function,which may find interesting applications in analysis,design and control of bio-networks.The exploration for the structural basis of the neural system is the key question to understand the mechanism of the functional performance.However,it is still a challenging problem to understand the functional segregation and integration by investigating the signal transferring at the basic neuronal connectivity level.In this work,for the the most complete neural system–C.elegans neuronal system,we analyzed the signal flow of the neuronal network with 302 neurons by the decomposition method,and identified the important neuronal circuits contributing to the two functions.The two different neuronal circuits by our methods not only involve the crucial neurons revealed by the previous experiments,but also imply the other neurons' functions.Furthermore,we identified various neuronal subcircuits which play different roles in the specific functional performance,and their relationship between two different functions.This work may provide the theoretical basis for the future experimental exploration for functional implements.