Abstract
The sensitive Ames test (the modified Kado microsuspension procedure) was applied to assess the mutagenicity of dust collected on filters in air conditioners. The major modification consists of using “amino acids enriched minimal glucose -agar base” developed by S. Arimoto to accelerate. growth of His+revertants and to shorten incubation period.
This procedure was approximately four to 18 times more sensitive than the modified Ames test (preincubation method by Yahagi et al.) for detecting mutagens in air particulate extracts and approximately four to 64 times more sensitive for the chemical mutagens, benzo (a) pyrene [B (a) P], 2-nitrofluorene [2-NF], 1-nitropyrene [1-NP] and 2-aminoanthracene [2-AA].
By using this method, it was able to obtain His revertant colonies of observable size after 18-24 h of incubation at 37°C.(48-72 h of incubation is required in original Ames test.)
The modified procedure was applied to assess the mutagenicity of dust collected on filters in six air conditioners in our institute. Dust in smoking room generally showed higher mutagenic activity than those in the other rooms (laboratory for atomic absorption spectrometry, laboratory for gas chromatography, laboratory for analysis of pesticide residues and so on).
It was suggested that the mutagenic activity, tar content and B (a) P content were generally related with the frequency of using fire.
Microsuspension procedure is applicable in testing sample of limitted mass.
