Tradescantia stamen hair mutation bioassay

Area of Science:

• Environmental Toxicology
• Genetics
• Biotechnology

Background:

• The International Programme on Chemical Safety (IPCS) initiated a collaborative study to assess plant-based mutagenicity testing systems.
• The Tradescantia stamen hair mutation (Trad-SH) assay (clone 4430) was selected for its potential as a mutagen screening tool.

Purpose of the Study:

• To evaluate the efficiency and reliability of the Trad-SH assay in detecting mutagens.
• To compare results across multiple international laboratories using standardized protocols.

Main Methods:

• Five laboratories in different countries tested four coded chemicals: azidoglycerol (AG), N-methyl-N-nitrosourea (MNU), sodium azide (NaN3), and maleic hydrazide (MH).
• Pink mutations in Tradescantia stamen hairs were scored between day 7 and day 14 following a standardized protocol.
• Data from individual laboratories were analyzed and compared after chemical codes were revealed.

Main Results:

• Azidoglycerol (AG) showed mutagenic effects at doses of 50-100 µg/ml in one of two testing labs.
• Maleic hydrazide (MH) produced positive mutagenic responses across all labs (1-45 µg/ml), though without a linear dose-response.
• N-methyl-N-nitrosourea (MNU) was mutagenic in all five labs (10-80 µg/ml), and sodium azide (NaN3) was mutagenic in three labs (3-80 µg/ml) despite toxicity.

Conclusions:

• The Trad-SH assay (clone 4430) is a reliable system for screening chemicals for mutagenic potential.
• The assay's utility extends beyond laboratory conditions, suggesting potential for in situ monitoring of environmental pollutants.