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Updated: May 2, 2026
Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System
Published on: December 21, 2016
Sensitivity of Salmonella YG5161 for detecting PAH-associated mutagenicity in air particulate matter
Gisela A Umbuzeiro1, Fábio Kummrow, Daniel Alexandre Morales
1Faculty of Technology, State University of Campinas (Unicamp), Limeira, SP, Brazil.
Abstract:
The Salmonella/microsome assay is the most used assay for the evaluation of air particulate matter (PM) mutagenicity and a positive correlation between strain TA98 responses and benzo[a]pyrene (B[a]P) levels in PM has been found. However, it seems that the major causes of PM mutagenicity in this assay are the nitro and oxy-PAHs. Salmonella YG5161, a 30-times more responsive strain to B[a]P has been developed. To verify if YG5161 strain was sufficiently sensitive to detect mutagenicity associated with B[a]P mutagenicity, PM samples were collected in Brazil and Sweden, extracted with toluene and tested in the Salmonella/microsome microsuspension assay. PAHs and B[a]P were determined and the extracts were tested with YG5161 and its parental strain TA1538. The extracts were also tested with YG1041 and its parental strain TA98. For sensitivity comparisons, we tested B[a]P and 1-nitropyrene (1-NP) using the same conditions. The minimal effective dose of B[a]P was 155 ng/plate for TA1538 and 7 ng/plate for YG5161. Although the maximum tested dose, 10 m(3) /plate containing 9 ng of B[a]P in the case of Brazilian sample, was sufficient to elicit a response in YG5161, mutagenicity was detected at a dose as low as 1 m(3) /plate (0.9 ng). This is probably caused by nitro-compounds that have been shown to be even more potent than B[a]P for YG5161. It seems that the mutagenicity of B[a]P present in PM is not detectable even with the use of YG5161 unless more efficient separation to remove the nitro-compounds from the PAH extract is performed.
Insights
The Salmonella/microsome assay detects air particulate matter mutagenicity. A new Salmonella strain, YG5161, is more sensitive to benzo[a]pyrene (B[a]P), but nitro-compounds interfere with detecting B[a]P mutagenicity.
Area of Science:
- Environmental Science
- Toxicology
- Genetics
Background:
- The Salmonella/microsome assay is standard for evaluating air particulate matter (PM) mutagenicity.
- A correlation exists between TA98 strain responses and benzo[a]pyrene (B[a]P) levels in PM.
- Nitro- and oxy-polycyclic aromatic hydrocarbons (PAHs) are major contributors to PM mutagenicity in this assay.
Purpose of the Study:
- To assess the sensitivity of the newly developed Salmonella YG5161 strain for detecting B[a]P mutagenicity in PM.
- To compare the mutagenicity detection capabilities of YG5161 and its parental strain TA1538, and YG1041 with TA98.
- To investigate the influence of nitro-PAHs on B[a]P mutagenicity detection in PM extracts.
Main Methods:
- Collected PM samples from Brazil and Sweden.
- Extracted PM samples with toluene and tested in the Salmonella/microsome microsuspension assay using strains YG5161, TA1538, YG1041, and TA98.
- Quantified PAHs and B[a]P, and compared sensitivity using B[a]P and 1-nitropyrene (1-NP).
Main Results:
- Salmonella YG5161 showed significantly higher sensitivity to B[a]P (7 ng/plate) compared to TA1538 (155 ng/plate).
- Mutagenicity was detected in YG5161 at lower PM doses (1 m³/plate) than previously observed, likely due to potent nitro-compounds.
- Despite YG5161's enhanced sensitivity, the mutagenicity of B[a]P in PM remained undetectable without removing interfering nitro-compounds.
Conclusions:
- The Salmonella YG5161 strain offers improved sensitivity for detecting B[a]P mutagenicity.
- Nitro-compounds present in PM extracts significantly impact and potentially mask the detection of B[a]P mutagenicity.
- Effective separation techniques are necessary to accurately assess B[a]P mutagenicity in air particulate matter using this assay.
