Mutagenicity of algal metabolites of benzo(a)pyrene for Salmonella typhimurium

Abstract

The metabolism and growth effects of benzo(a)pyrene (BaP) were studied using a freshwater green alga, Selenastrum capricornutum. Algal cultures were incubated under gold light with BaP added at concentrations of 40, 160, 400, and 1,200 micrograms/liter for the periods of 1-4 days. The metabolites and BaP were identified and quantified from ethyl acetate extracts of both algal cells and incubation medium. The ethyl acetate extracts were evaluated for genotoxicity using a micro-volume Salmonella typhimurium forward mutation assay with resistance to 8-azaguanine for selection. This assay detected the presence of small quantities of BaP and was particularly sensitive to the mutagenicity of BaP diols. Of those extracts prepared from algae and medium from cultures exposed to 400 micrograms BaP/liter (10 micrograms/25 ml culture), only algal cell extracts from one day's growth were mutagenic. In cultures exposed to 1,200 micrograms BaP/liter (30 micrograms/25 ml culture), mutagenic materials were produced or persisted in both algae and media throughout the 4-day incubation. The observed mutagenic response can be attributed in part to the presence of unmetabolized BaP or to BaP diols.

Contribution à l'évaluation écotoxicologique du Tébuthiuron - un herbicide de la classe des urées substituées

“…En effet, différentes interactions (détoxication, activation, accumulation) sont possibles lorsque des végétaux sont exposés à des produits chimiques ayant un potentiel génotoxique (LEVINE, 1984 ;PLEWA et ai, 1984 ;SCHOENY, 1985 ;HARWOOD et ai, 1989). Le choix de 1 mg • L~1 de TB comme concentration d'exposition à S. caphcornutum repose sur les résultats d'un test de pré-exposition de type « exposition-récupération •> où les algues ont été soumises à une gamme de concentrations de TB durant 4 h (fiQ-2).…”

Promutagen Activation by the Green Alga Selenastrum Capricornutum

“…Although green plants are known to activate many compounds, few studies have examined the activation of promutagens by the protists [12][13][14][15]. We have recently identified and characterized an ascorbate-dependent peroxidase in the unicellular green alga Selenastrum capricornutum [16].…”

Promutagen activation by the green algaSelenastrum capricornutum

“…Although green plants are known to activate many compounds, few studies have examined the activation of promutagens by the protists [12–15]. We have recently identified and characterized an ascorbate‐dependent peroxidase in the unicellular green alga Selenastrum capricornutum [16].…”