A protease-based biosensor for the detection of schistosome cercariae

Abstract

Parasitic diseases affect millions of people worldwide, causing debilitating illnesses and death. Rapid and cost-effective approaches to detect parasites are needed, especially in resource-limited settings. A common signature of parasitic diseases is the release of specific proteases by the parasites at multiple stages during their life cycles. To this end, we engineered several modular Escherichia coli and Bacillus subtilis whole-cell-based biosensors which incorporate an interchangeable protease recognition motif into their designs. Herein, we describe how several of our engineered biosensors have been applied to detect the presence and activity of elastase, an enzyme released by the cercarial larvae stage of Schistosoma mansoni. Collectively, S. mansoni and several other schistosomes are responsible for the infection of an estimated 200 million people worldwide. Since our biosensors are maintained in lyophilised cells, they could be applied for the detection of S. mansoni and other parasites in settings without reliable cold chain access.

<i>Escherichia coli</i> as a Model Organism and Its Application in Biotechnology

“…Using qualitative reporters can be applied in ield research [70]. One good example is the detection of parasites without using cold-protected samples or complicated equipment for the detection process [86].…”

Opportunities for applying whole‐cell bioreporters towards parasite detection

“…To demonstrate these advantages, we recently designed and tested several WCBs that were engineered to detect Schistosoma mansoni, one of the causative agents of schistosomiasis (Webb et al, 2016). In our study, we used both E. coli and B. subtilis as the WCB chassis, which were designed to detect the presence of the elastase enzyme released by the cercarial larvae, as part of the infection process of primary hostssuch as humans (Gryseels et al, 2006).…”

“…This anchor is fused to a flexible linker module, which also comprises the cercarial elastase peptide recognition motif, which is then further fused to a tag module that can be antibody-labelled ( Fig. 1A; Webb et al, 2016). Thus, in the presence of viable cercariae the elastase recognition motif of these WCBs will be cleaved and, via the release of the antibody-labelled tag results in a detectable loss of colour, in the presence of the parasite (Fig.…”

“…One important issue that must be considered is the schistosoma cercarial detection limit of the WCBs. We previously considered what the detection limit might be in terms of the amount of elastase released by each individual cercarial larva and based upon our analyses we estimated that each larva produces elastase in the pg range (Webb et al, 2016). Therefore, we concluded that as the level of cercariae present in infected water courses can vary greatly, we may need to concentrate the number of cercariae present in the volume of water sample tested to enable detection using our WCBs.…”

FRET-Based Enzyme Activity Reporter: Practical Hints for Kinases as Indicators of Virulence

“…and Trypanosoma cruzi [3]). The abovementioned enzymes have been regarded from two angles, leading either to the development of inhibitory strategies or biosensors development [4].…”