Engineered acetoacetate-inducible whole-cell biosensors based on the AtoSC two-component system

Abstract

Whole cell biosensors have great potential to be used as diagnostic and treatment tools in biomedical applications. Bacterial biosensors that respond to specific metabolites can help analyze spatio-temporal gradients in the body or cue expression of therapeutic agents in diseased sites. In this study, we developed an acetoacetate bacterial sensor by inserting the promoter of the atoSC two-component system (TCS) into a promoterless GFP expression plasmid and transformed it into E. coli DH5α and E. coli Nissle 1917, which both contain the atoSC TCS. This bacterial biosensor has a dynamic range of 0.01-1mM of acetoacetate, which is within the range of physiological concentrations in the blood, and exhibits up to a 100-fold change of induced GFP expression as measured by relative fluorescence. Comparing combinations among the two host strains and high/low-copy plasmid variations of the biosensor, we observed the fastest and highest response to acetoacetate with the E. coli Nissle 1917 low copy plasmid biosensor. Induction experiments on the biosensor using 50mM of the short chain fatty acids (SCFA) acetate, proprionate, and butyrate showed no response, indicating its specificity between acetoacetate and SCFAs. This acetoacetate bacterial sensor is a valuable contribution to the library of biosensors that may eventually be used for in vivo clinical applications.keywords: atoSC two-component system, synthetic biology, whole cell biosensor

Automated design of gene circuits with optimal mushroom-bifurcation behaviour

“…Interestingly this variety of behaviours was attained mainly by inducing differences in the degradation rates of the genes of the network, which is a common perturbation tool in synthetic biology Cameron & Collins (2014), and opens the door to the exploration of novel dynamical behaviour when protein degradation is coupled to other synthetic circuits Cookson et al (2011), Prindle et al (2014). The most interesting bifurcation diagram found is the isola, which not only could be useful for error checking of deployed biosensors, but could be useful in clinical applications, for example in vivo detection of inflammation (Riglar et al 2017) or metabolite levels (Rutter et al 2019, 2021). Finally, the minimal mushroom topologies identified reveal a new way to create multistable systems, avoiding the need for loading a single bistable switch with additional autoregulation (Lou et al 2010, Wu et al 2017, Leon et al 2016).…”

Engineering a symbiont as a biosensor for the honey bee gut environment

“…The development of tools to obtain spatial and/or temporal information in situ is hence much required to untangle the convoluted and dynamic interplay occurring within the microbiota and with its host. Synthetic biology holds promise to advance the field in this direction by engineering human commensal bacteria as live biosensors [7][8][9][10] .…”

Development of Lactococcus lactis Biosensors for Detection of Diacetyl

“…A plethora of biosensors have been developed over the past decades for biotechnological and medical applications (Close et al, 2009;Zhang and Keasling, 2011;Brutesco et al, 2017). One example of transcription-based biosensors is an E. coli acetoacetate sensor based on the GFP expression driven by the promoter of the atoSC genes encoding a two-component system, which is activated by acetoacetate (Gonzales et al, 2016).…”