Effects of Hg(II) exposure on MAPK phosphorylation and antioxidant system in D. melanogaster.
The heavy metal mercury is a known toxin, but while the mechanisms involved in mercury toxicity have been well demonstrated in vertebrates, little is known about toxicological effects of this metal in invertebrates. Here, we present the results of our study investigating the effects associated with exposure of fruit fly Drosophila melanogaster to inorganic mercury (HgCl2 ). We quantify survival and locomotor performance as well as a variety of biochemical parameters including antioxidant status, MAPK phosphorylation and gene expression following mercury treatment. Our results demonstrate that exposure to Hg(II) through diet induced mortality and affected locomotor performance as evaluated by negative geotaxis, in D. melanogaster. We also saw a significant impact on the antioxidant system including an inhibition of acetylcholinesterase (Ache), glutathione S-transferase (GST) and superoxide dismutase (SOD) activities. We found no significant alteration in the levels of mRNA of antioxidant enzymes or NRF-2 transcriptional factor, but did detect a significant up regulation of the HSP83 gene. Mercury exposure also induced the phosphorylation of JNK and ERK, without altering p38(MAPK) and the concentration of these kinases. In parallel, Hg(II) induced PARP cleavage in a 89 kDa fragment, suggesting the triggering of apoptotic cell death in response to the treatment. Taken together, this data clarifies and extends our understanding of the molecular mechanisms mediating Hg(II) toxicity in an invertebrate model.
Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900, Brazil.
M T
MT
Paula
A P
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Zemolin
A P
AP
Vargas
R M
RM
Golombieski
E L S
EL
Loreto
A P
AP
Saidelles
R S
RS
Picoloto
E M M
EM
Flores
A B
AB
Pereira
J B T
JB
Rocha
T J S
TJ
Merritt
J L
JL
Franco
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Posser
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D004331:Drosophila melanogaster / Q000187:drug effects* / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D015227:Lipid Peroxidation; D008124:Locomotion / Q000187:drug effects; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008627:Mercuric Chloride / Q000633:toxicity; D008628:Mercury / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation; D013482:Superoxide Dismutase / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D000975:Antioxidants; D008627:Mercuric Chloride; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000110:Acetylcholinesterase; D008628:Mercury