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Updated: Aug 1, 2025
High-Throughput Screening of Microbial Isolates with Impact on Caenorhabditis elegans Health
Published on: April 28, 2022
Host-microbiota affects the toxicity of Aflatoxin B1 in Caenorhabditis elegans
Bowen Tang1, Kathy S Xue1, Jia-Sheng Wang1
1Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, 30602, USA.
Abstract:
Aflatoxins are a group of potent fungal metabolites produced by Aspergillus and commonly contaminate groundnuts and cereal grains. Aflatoxin B1 (AFB1), the most potent mycotoxin, has been classified as Group 1 human carcinogen because it can be metabolically activated by the cytochrome P450 (CYP450) in the liver to form AFB1-DNA adducts and induce gene mutations. Increasing evidence has shown the gut microbiota as a key mediator of AFB1 toxicity through multiple interactive host-microbiota activities. To identify specific bacterial activity that modulates AFB1 toxicity in Caenorhabditis (C.) elegans, we established a 3-way (microbe-worm-chemical) high-throughput screening system using C. elegans fed E. coli Keio collection on an integrated robotic platform, COPAS Biosort. We performed 2-step screenings using 3985 Keio mutants and identified 73 E. coli mutants that modulated C. elegans growth phenotype. Four genes (aceA, aceB, lpd, and pflB) involved in the pyruvate pathway were identified from the screening and confirmed to increase the sensitivity of all animals to AFB1. Taking together, our results indicated that disturbances in bacterial pyruvate metabolism might have a significant impact on AFB1 toxicity in the host.
Insights
Disturbances in bacterial pyruvate metabolism significantly impact aflatoxin B1 (AFB1) toxicity. This study identified specific E. coli genes affecting AFB1 sensitivity in Caenorhabditis elegans, offering insights into host-microbe interactions.
Area of Science:
- Microbiology
- Toxicology
- Genetics
Background:
- Aflatoxins, potent fungal toxins, contaminate food and are Group 1 human carcinogens.
- Aflatoxin B1 (AFB1) is activated by cytochrome P450, forming DNA adducts and inducing mutations.
- Gut microbiota plays a crucial role in mediating AFB1 toxicity through host-microbe interactions.
Purpose of the Study:
- To identify specific bacterial activities modulating AFB1 toxicity.
- To investigate the role of bacterial pyruvate metabolism in AFB1 sensitivity.
- To establish a high-throughput screening system for microbe-chemical-host interactions.
Main Methods:
- Utilized a 3-way (microbe-worm-chemical) high-throughput screening system with Caenorhabditis elegans and E. coli Keio mutants.
- Employed an integrated robotic platform (COPAS Biosort) for screening 3985 E. coli mutants.
- Performed 2-step screenings to identify mutants affecting C. elegans growth phenotype.
Main Results:
- Identified 73 E. coli mutants that modulated C. elegans growth.
- Pinpointed four genes (aceA, aceB, lpd, pflB) in the pyruvate pathway.
- Confirmed that these pyruvate pathway genes increase host sensitivity to AFB1.
Conclusions:
- Bacterial pyruvate metabolism significantly influences AFB1 toxicity in the host.
- Disturbances in bacterial metabolism can alter susceptibility to mycotoxins.
- The findings provide a foundation for understanding host-microbiota-toxin interactions.
