Toxicity of the quinalphos metabolite 2-hydroxyquinoxaline: growth inhibition, induction of oxidative stress, and genotoxicity in test organisms.
The quinalphos metabolite 2-hydroxyquinoxaline (HQO), previously shown to photocatalytically destroy antioxidant vitamins and biogenic amines in vitro, was tested for toxicity in several small aquatic organisms and for mutagenicity in Salmonella typhimurium. In the rotifer Philodina acuticornis, HQO caused the disappearance of large individuals and increased hydroperoxide concentration. The latter effect was not only observed in animals kept in a light/dark cycle, but also in constant darkness, indicating that HQO can assume a reactive state and/or form reactive intermediates under the influence of either light or redox-active metabolites, in particular, free radicals. Cell proliferation was inhibited in the ciliate Paramecium bursaria. In the dinoflagellate Lingulodinium polyedrum, which allows early detection of cellular stress on the basis of bioluminescence measurements, strong rises in light emission became apparent on the 2nd day of exposure to HQO and continued until cells died between 12 and 18 days of treatment. Oxidative damage of protein by HQO was demonstrated by measuring protein carbonyl in L. polyedrumin vivo as well as in light-exposed bovine serum albumin in vitro. In an Ames test of mutagenicity, HQO proved to be genotoxic in both light- and dark-exposed bacteria. HQO appears as a source of secondary quinalphos toxicity, which deserves further attention.
Riediger
Sonja
S
Institute of Zoology and Anthropology, University of Goettingen, Berliner Str. 28, D-37073 Goettingen, Germany.
Behrends
Andreas
A
Croll
Björn
B
Vega-Naredo
Ignacio
I
Hänig
Nils
N
Poeggeler
Burkhard
B
Böker
Jutta
J
Grube
Sascha
S
Gipp
Juliane
J
Coto-Montes
Ana
A
Haldar
Chandana
C
Hardeland
Rüdiger
R
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D004141:Dinoflagellida / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D007306:Insecticides / Q000378:metabolism / Q000633:toxicity; D008027:Light; D008163:Luminescent Measurements; D009152:Mutagenicity Tests; D009946:Organothiophosphorus Compounds / Q000378:metabolism / Q000633:toxicity*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D010247:Paramecium / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D011810:Quinoxalines / Q000378:metabolism / Q000633:toxicity*; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D013997:Time Factors
D007306:Insecticides; D009946:Organothiophosphorus Compounds; D011810:Quinoxalines; C098565:2-hydroxyquinoxaline; C009145:quinalphos