Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: A model for generating circadian rhythm by coupling ultradian oscillators | Theoretical Biology and Medical Modelling BioMed Central Research Open Access A model for generating circadian rhythm by coupling ultradian oscillators Verner Paetkau 1 Roderick Edwards2 and Reinhard Illner2 Address Department of Biochemistry and MicrobiologyUniversity of Victoria Victoria British Columbia Canada and 2Department of Mathematics and Statistics University of VictoriaVictoria British Columbia Canada Email Verner Paetkau - vhp@ Roderick Edwards - edwards@ Reinhard Illner - rillner@ Corresponding author Published 23 February 2006 Received 06 September 2005 Theoretical Biology and Medical Modelling 2006 3 12 doi 1742-4682-3-12 Accepted 23 February 2006 This article is available from http content 3 1 12 2006 Paetkau et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Organisms ranging from humans to cyanobacteria undergo circadian rhythm that is variations in behavior that cycle over a period about 24 hours in length. A fundamental property of circadian rhythm is that it is free-running and continues with a period close to 24 hours in the absence of light cycles or other external cues. Regulatory networks involving feedback inhibition and feedforward stimulation of mRNA transcription and translation are thought to be critical for many circadian mechanisms and genes coding for essential components of circadian rhythm have been identified in several organisms. However it is not clear how such components are organized to generate a circadian oscillation. Results We propose a model in which two independent transcriptional-translational oscillators with periods much shorter than 24 hours are coupled to drive a forced oscillator that has a .
