Ratiometric Gas Reporting: A Nondisruptive Approach To Monitor Gene Expression in Soils.
Hsiao-Ying ChengCaroline A MasielloIlenne Del ValleXiaodong GaoGeorge N BennettJonathan J SilbergPublished in: ACS synthetic biology (2018)
Fluorescent proteins are ubiquitous tools that are used to monitor the dynamic functions of natural and synthetic genetic circuits. However, these visual reporters can only be used in transparent settings, a limitation that complicates nondisruptive measurements of gene expression within many matrices, such as soils and sediments. We describe a new ratiometric gas reporting method for nondisruptively monitoring gene expression within hard-to-image environmental matrices. With this approach, C2H4 is continuously synthesized by ethylene forming enzyme to provide information on viable cell number, and CH3Br is conditionally synthesized by placing a methyl halide transferase gene under the control of a conditional promoter. We show that ratiometric gas reporting enables the creation of Escherichia coli biosensors that report on acylhomoserine lactone (AHL) autoinducers used for quorum sensing by Gram-negative bacteria. Using these biosensors, we find that an agricultural soil decreases the bioavailable concentration of a long-chain AHL up to 100-fold. We also demonstrate that these biosensors can be used in soil to nondisruptively monitor AHLs synthesized by Rhizobium leguminosarum and degraded by Bacillus thuringiensis. Finally, we show that this new reporting approach can be used in Shewanella oneidensis, a bacterium that lives in sediments.
Keyphrases
- gene expression
- heavy metals
- living cells
- quantum dots
- dna methylation
- fluorescent probe
- adverse drug
- room temperature
- escherichia coli
- sensitive detection
- risk assessment
- human health
- genome wide
- hydrogen peroxide
- organic matter
- label free
- healthcare
- copy number
- single cell
- energy transfer
- climate change
- polycyclic aromatic hydrocarbons
- single molecule
- transcription factor
- oxide nanoparticles
- cell therapy
- stem cells
- health information
- multidrug resistant
- staphylococcus aureus
- nitric oxide
- bone marrow
- bacillus subtilis