Highly Sensitive Whole-Cell Biosensor for Cadmium Detection Based on a Negative Feedback Circuit

Zhang, Guangbao; Hu, Shuting; Jia, Xiaoqiang

doi:10.3389/fbioe.2021.799781

Cited by 14 publications

(7 citation statements)

References 51 publications

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“…Therefore, we need to expand our cross-reactivity analysis and incorporate parts with only specific reactions to their analytes, generated via directed evolution [ 40 ]. Finally, a feedback circuit [ 41 ] or a genetic amplifier [ 42 ] could extend our recombinase-based WCB to improve detection limits.…”

Section: Resultsmentioning

confidence: 99%

A Recombinase-Based Genetic Circuit for Heavy Metal Monitoring

et al. 2022

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Rapid progress in the genetic circuit design enabled whole-cell biosensors (WCBs) to become prominent in detecting an extensive range of analytes with promise in many fields, from medical diagnostics to environmental toxicity assessment. However, several drawbacks, such as high background signal or low precision, limit WCBs to transfer from proof-of-concept studies to real-world applications, particularly for heavy metal toxicity monitoring. For an alternative WCB module design, we utilized Bxb1 recombinase that provides tight control as a switch to increase dose-response behavior concerning leakiness. The modularity of Bxb1 recombinase recognition elements allowed us to combine an engineered semi-specific heat shock response (HSR) promoter, sensitive to stress conditions including toxic ions such as cadmium, with cadmium resistance regulatory elements; a cadmium-responsive transcription factor and its cognitive promoter. We optimized the conditions for the recombinase-based cadmium biosensor to obtain increased fold change and shorter response time. This system can be expanded for various heavy metals to make an all-in-one type of WCB, even using semi-specific parts of a sensing system.

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Section: Resultsmentioning

confidence: 99%

A Recombinase-Based Genetic Circuit for Heavy Metal Monitoring

et al. 2022

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“…P. putida KT2440 has been engineered to improve sensitivity and specificity to Cd ( Zhang et al, 2021 ). In the whole-cell biosensor, CadR expression was maintained at a low level by a negative feedback loop and the mcherry gene was regulated by CadR.…”

Section: Heavy Metal Detectionmentioning

confidence: 99%

Synthetic bacteria for the detection and bioremediation of heavy metals

Thai

Lim

2023

Front. Bioeng. Biotechnol.

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Toxic heavy metal accumulation is one of anthropogenic environmental pollutions, which poses risks to human health and ecological systems. Conventional heavy metal remediation approaches rely on expensive chemical and physical processes leading to the formation and release of other toxic waste products. Instead, microbial bioremediation has gained interest as a promising and cost-effective alternative to conventional methods, but the genetic complexity of microorganisms and the lack of appropriate genetic engineering technologies have impeded the development of bioremediating microorganisms. Recently, the emerging synthetic biology opened a new avenue for microbial bioremediation research and development by addressing the challenges and providing novel tools for constructing bacteria with enhanced capabilities: rapid detection and degradation of heavy metals while enhanced tolerance to toxic heavy metals. Moreover, synthetic biology also offers new technologies to meet biosafety regulations since genetically modified microorganisms may disrupt natural ecosystems. In this review, we introduce the use of microorganisms developed based on synthetic biology technologies for the detection and detoxification of heavy metals. Additionally, this review explores the technical strategies developed to overcome the biosafety requirements associated with the use of genetically modified microorganisms.

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“…Among the circuits that followed, biosensors became the object of many research works due to their numerous possible applications 4 . Biosensors have been engineered to respond to several different inputs, e.g., heavy metals 5 , 6 , metabolites 7 , organophosphates 8 2,4-dinitrotoluene 9 , intracellular xylose 10 , and arsenic 11 .…”

Section: Introductionmentioning

confidence: 99%

Engineering a two-gene system to operate as a highly sensitive biosensor or a sharp switch upon induction with β-estradiol

Zhou

Liang

Marchisio

2022

Sci Rep

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The human estrogen receptor has been used for about thirty years, in the yeast S. cerevisiae, as a component of chimeric transcription factors. Its ligand, β-estradiol, permits to control the protein translocation into the nucleus and, as a consequence, the expression of the gene(s) targeted by the synthetic transcription factor. Activators that are orthogonal to the yeast genome have been realized by fusing the human estrogen receptor to an activation and a DNA-binding domain from bacteria, viruses, or higher eukaryotes. In this work, we optimized the working of a β-estradiol-sensing device—in terms of detection range and maximal output signal—where the human estrogen receptor is flanked by the bacterial protein LexA and either the strong VP64 (from herpes simplex virus) or the weaker B42 (from E. coli) activation domain. We enhanced the biosensor performance by thoroughly engineering both the chimeric activator and the reporter protein expression cassette. In particular, we constructed a synthetic promoter—where transcription is induced by the chimeric activators—based on the core sequence of the yeast CYC1 promoter, by tuning parameters such as the length of the 5′ UTR, the distance between adjacent LexA binding sites (operators), and the spacing between the whole operator region and the main promoter TATA box. We found a configuration that works both as a highly sensitive biosensor and a sharp switch depending on the concentration of the chimeric activator and the strength of its activation domain.

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Highly Sensitive Whole-Cell Biosensor for Cadmium Detection Based on a Negative Feedback Circuit

Cited by 14 publications

References 51 publications

A Recombinase-Based Genetic Circuit for Heavy Metal Monitoring

A Recombinase-Based Genetic Circuit for Heavy Metal Monitoring

Synthetic bacteria for the detection and bioremediation of heavy metals

Engineering a two-gene system to operate as a highly sensitive biosensor or a sharp switch upon induction with β-estradiol

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