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Figure 2 | BMC Systems Biology

Figure 2

From: A predictive computational model of the kinetic mechanism of stimulus-induced transducer methylation and feedback regulation through CheY in archaeal phototaxis and chemotaxis

Figure 2

Illustration of the flow assay used for measuring transient demethylation rates. The assay performed by [3436, 38] to detect demethylation rates of Halobacterium salinarum is a slight variation of an assay originally used for E. coli [40]. Cells are incubated in the presence of [methyl-3H]-methionine and puromycine (inhibitor of protein biosynthesis) to label the transducer methyl-groups. Cells are then transferred to the filter unit and chemotaxis stimuli are applied by switching between complex medium (without peptone) and complex medium with peptone. Phototaxis stimuli are applied by exposing the cells on the filter to light. Fractions are collected with fixed sampling rate T S and are subsequently processed by liquid scintillation counting to determine the release of volatile [methyl-3H]-methionine as [methyl-3H]-methanol. Due to turbulent flow and mixing kinetics, the measurements and the chemo-stimuli are subject to certain dynamics (time constants T in , T out , and T delay ) that extend the time course of the methanol release [35, 36]. For further details see Methods.

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