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Abstracts

XX conference

Modeling of biorhythms synchronization at different levels of system description

Zakharov A.P., Bratsun D.A.

Russia, 614600, Perm, Sibirskaya 24, (342)238-63-64, az1211@mail.ru, dmitribratsun@rambler.ru

1 pp. (accepted)

It is known that cyclic processes are typical for all levels of organism activity, beginning with processes of transcription/translation of genes and finishing with such external manifestations of activity of an organism on the whole as sleeping- wakefulness. There are three characteristic scales of the system description: microscopical (level of several genes), mezoscopical (cell level) and macroscopical (organism level). A certain approach is needed for studying the rhythms at each level.

On the basic level of description where the role of fluctuations is important, Gillespie method [1] was applied to numerically investigate the effect of synchronization of delayed stochastic fluctuations in a repressilator consisting of three genes. Mechanisms of synchronization and influence on the process of intrinsic noise are revealed. At a mezoscopical level synchronization of circadian rhythms is considered on the basis of a spatially extended dynamical model offered before [2]. Studies were made of the interaction of several cells that exchange chemical signals and establish collective behaviour. For the numerical solution of the task a new method of solving the problems of reaction-diffusion with time-delay was developed, that does not demand data storage for all time-slices within time-delay.

A macroscopical level of description is presented by numerical research of the model of growth of epithelial tissue offered in [3], which is complemented by the mechanism of circadian rhythms in separate cells and the possibility of direct exchange of signals through cellular membranes. As more than one thousand cells are involved in simulations at the same time, it allowed revealing the macroscopical effects which are invisible on the level of a cell. In particular, the appearance of synchronization waves is discovered that is consistent to the results of recent experimental works.

The work was supported by the Department of Science and Education of Perm region (project C26/244) and Program Strategic Development of Perm State Humanitarian Pedagogical University (project 031-F).

References

1. Bratsun D., Volfson D., Hasty J., Tsimring L. Delay-induced stochastic oscillations in gene regulation // PNAS, 2012. – Vol. 102, N. 41. – pp. 14593-14598.

2. Bratsun D.A., Zakharov A.P. Modeling spatio-temporal dynamics of circadian rhythms in Neurospora crassa, Computer Research and Modeling, Vol. 3, N. 2, pp. 191–213 (2011).

3. Salm М., Pismen L.M. Chemical and mechanical signaling in epithelial spreading // Phys. Biol. 2012. – Vol. 9, N. 2. – p. 026009.



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