Chromogenic Escherichia coli reporter strain for screening DNA damaging agents

Abstract

The presence of pollutants in soil and water has given rise to diverse analytical and biological approaches to detect and measure contaminants in the environment. Using bacterial cells as reporter strains represents an advantage for detecting pollutants present in soil or water samples. Here, an Escherichia coli reporter strain expressing a chromoprotein capable of interacting with soil or water samples and responding to DNA damaging compounds is validated. The reporter strain generates a qualitative signal and is based on the expression of the coral chromoprotein AmilCP under the control of the recA promoter. This strain can be used simply by applying soil or water samples directly and rendering activation upon DNA damage. This reporter strain responds to agents that damage DNA (with an apparent detection limit of 1 µg of mitomycin C) without observable response to membrane integrity damage, protein folding or oxidative stress generating agents, in the latter case, DNA damage was observed. The developed reporter strain reported here is effective for the detection of DNA damaging agents present in soils samples. In a proof-of-concept analysis using soil containing chromium, showing activation at 15.56 mg/L of Cr(VI) present in soil and leached samples and is consistent with Cr(III) toxicity at high concentrations (130 µg). Our findings suggest that chromogenic reporter strains can be applied for simple screening, thus reducing the number of samples requiring analytical techniques.

Biologically synthesized silver nanoparticles as potent antibacterial effective against multidrug-resistant Pseudomonas aeruginosa

“…The bacterial cell, and DNA damage induced by the nanoparticles were evaluated using biosensors containing the promoter regions of the genes uspA, recA and fabA , fused to the blue chromo‐protein AmilCP, which construction was described in Mora‐Garduño et al. (2022). To determine general stress, DNA damage and membrane damage respectively, a biosensor reporter strain was used.…”

“…Evaluation of cell and DNA damage using biosensors The bacterial cell, and DNA damage induced by the nanoparticles were evaluated using biosensors containing the promoter regions of the genes uspA, recA and fabA, fused to the blue chromo-protein AmilCP, which construction was described in Mora-Garduño et al (2022).…”

High-Throughput Screening Method Using Escherichia coli Keio Mutants for Assessing Primary Damage Mechanism of Antimicrobials

“…As a proof-of-concept, a previously reported plasmid bearing the recA promoter controlling the expression of a chromoprotein (AmilCP) [16] was transformed into BW25113 and ∆recA strains to evaluate the sensitivity of the reporter plasmid in the parental and mutant genetic backgrounds. Transformant cells were tested as described previously and transformants were selected in LB-ampicillin (200 µg/mL) [16]. Plates were recorded using a digital camera.…”

“…We showed that the silver NPs produced cell membrane and DNA damage, and that the plausible mechanism of both damaged structures is the production of ROS [15]. The value of bioreporter strains is that the effect of antimicrobials and nanomaterials may be determined based on primary damage information in vivo [16].…”

“…Microorganisms 2024, 12, 793 2 of 16 Furthermore, mobile genetic elements, such as plasmids, encode bona fide resistance genes, some of which are clinically relevant, and the effect of the environment as a selective pressure to enhance the transmission of such elements is important [5,6]. Beyond these, deciphering the remaining physiological cell response mechanisms involved in antibiotic resistance is a fertile field for discovering novel targets for controlling multi-resistant microorganisms.…”