Discrete and Continuum Multiscale Behaviour in Bacterial Communication - Multiscale Computer Modeling in Biomechanics and Biomedical Engineering - page 294

Discrete and Continuum Multiscale
Behaviour in Bacterial Communication

Sara Jabbari and John R. King

Abstract The interacting effects operating on subcellular (gene regulatory pro-
cesses), cellular (interactions between neighbouring cells) and population (sig-
nalling molecule transport) scales are exemplified and explored through simple
multiscale models. Specific attention is focused on how the upregulation (or
downregulation) of small numbers of discrete cells can influence the behaviour of
the population as a whole, by investigating toy models for positive autoregulation
and by the simulation of a much more detailed model for quorum sensing within a
Gram-positive population of bacteria. The implications for delays associated with
gene expression are also investigated in a spatio-temporal context through the
analysis of blow-up behaviour, as a mathematical symptom of upregulation
through positive feedback, in some model reaction-diffusion delay equations.

1 Bacterial Communication

The belief that bacteria within a colony operate independently of one another was
abandoned in the 1970s with the discovery of cell-density dependent behaviour in
the marine bacterium Vibrio fischeri [ 16 ]. It was found that these bacteria emit
light only when present at sufficiently high concentrations, most likely either to
obtain camouflage from predators (by mimicking moonlight on the water's sur-
face) or to attract mates; at lower bacterial concentrations, the amount of light

S. Jabbari
University of Birmingham, Edgbaston, Birmingham B15 2TT, England
e-mail: [e-mail]
J. R. King (

)
Centre for Mathematical Medicine and Biology, University of Nottingham,
University Park, Nottingham NG7 2RD, UK
e-mail: [e-mail]

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