An Integrative Approach to Computational Modelling of the Gene Regulatory Network Controlling Clostridium botulinum Type A1 Toxin Production
Fig 3
Diagrammatic representation of the computational gene expression sub-model.
(Top Left) show the role of the BotR sigma factor, and of the three TCSs reported to regulate positively toxigenesis in C. botulinum Group I type A1 strain, along with the negative TCS regulator. (Top Right) our hypothesis of how the availability of nutrients (species N) regulates directly and indirectly (via CodY) toxin production, and how the quorum sensing signal (species S) together with the two positive TCS regulators, recognise the quorum-sensing pathway whose effect on toxin production was experimentally observed in the work of Cooksely and colleagues [28]. (Lower), the dashed arrows represent regulation mechanisms, whereas solid lines model mass transfer reactions. The species N (Nutrients) and S (quorum-sensing signal) are shared with the population sub-model. The state of each bacterial cell is assumed to be the same. Species CBO_0786, CBO_0787 (and their phospho forms), BotR and BoNT are subject to degradation (reactions not graphically depicted).