Bacterial reduction in genotoxicity of Direct Red 28 dye.
Direct Red 28 (DR28) is a benzidine-based azo dye widely used in several countries. It has also been a subject of intense research for its anti-prion activity. Like other benzidine-based azo dyes, it is also carcinogenic and toxic. However, there are very few studies addressing its detoxification. In the present study, a Bacillus velezensis strain was used for detoxification of DR28. Toxicity was checked by a battery of highly sensitive genotoxicity assays like comet assay, DNA ladder formation, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and flow cytometric Annexin V binding assay. HL-60 cell line was used as the test system. All the assays showed an initial increase in toxicity upon biodegradation due to release of mutagenic products, like benzidine and 4-aminobiphenyl, from the dye. These intermediates caused significant DNA damage and induced apoptosis in HL-60 cells. Then the culture degraded these mutagenic intermediates, due to which the toxicity was reduced gradually, finally resulting in nearly complete detoxification.
Bafana
Amit
A
Environmental Biotechnology Division, National Environmental Engineering Research Institute, Nagpur, India. abafana@rediffmail.com
Jain
Minakshi
M
Agrawal
Gaurav
G
Chakrabarti
Tapan
T
D000704:Analysis of Variance; D017304:Annexin A5; D001407:Bacillus / Q000378:metabolism*; D001673:Biodegradation, Environmental; D045744:Cell Line, Tumor; D020552:Comet Assay; D003224:Congo Red / Q000633:toxicity*; D053938:DNA Fragmentation / Q000187:drug effects*; D004787:Environmental Pollution / Q000517:prevention & control*; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D009152:Mutagenicity Tests
D017304:Annexin A5; D003224:Congo Red