Tributyltin inhibits the oligomycin-sensitive Mg-ATPase activity in Mytilus galloprovincialis digestive gland mitochondria.
Tributyltin (TBT), widely employed in the past in antifouling paints, is one of the most toxic organic pollutants. Although recently banned, it still threatens coastal water ecosystems and accumulates in filter-feeding molluscs. TBT is known to act as a membrane-active toxicant; however data on mussels are scanty and exposure effects on mitochondrial ATPase activities remain hitherto unexplored. TBT effects on the mitochondrial Mg-ATPase activities in the digestive gland of Mytilus galloprovincialis were investigated both in vitro and in TBT-exposed mussels. Both an oligomycin-sensitive Mg-ATPase (OS Mg-ATPase) (70% of total Mg-ATPase activity) and an oligomycin-insensitive ATPase (OI Mg-ATPase) (30%) were found. The OS-Mg-ATPase was as much as 70% in vitro inhibited by 0.7 μM (203 μg/L) TBT, while higher concentrations promoted a partial inhibition release up to 5.0 μM TBT; higher than 10.0 μM TBT concentrations yielded nearly complete enzyme inhibition. Concentrations higher than 1 μM TBT enhanced the OI Mg-ATPase. Mussels exposed to 0.5 and 1.0 μg/L TBT in aquaria showed a 30% depressed OS Mg-ATPase activity, irrespective of TBT dose and exposure time (24 and 120 h). The OI Mg-ATPase activity was apparently refractory to TBT exposure and halved both in control and TBT-exposed mussels after 120 h exposure.
Ventrella
Vittoria
V
Department of Biochemistry "G. Moruzzi", Section of Veterinary Biochemistry, University of Bologna, Via Tolara di sopra, 50-40064 Ozzano Emilia (BO), Italy. vittoria.ventrella@unibo.it
Nesci
Salvatore
S
Trombetti
Fabiana
F
Bandiera
Patrizia
P
Pirini
Maurizio
M
Borgatti
Anna Rosa
AR
Pagliarani
Alessandra
A
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004064:Digestive System / Q000201:enzymology / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D049878:Mytilus / Q000187:drug effects* / Q000201:enzymology; D009840:Oligomycins / Q000633:toxicity; D014220:Trialkyltin Compounds / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D009840:Oligomycins; D014220:Trialkyltin Compounds; D014874:Water Pollutants, Chemical; C011559:tributyltin; D017301:Ca(2+) Mg(2+)-ATPase