19 Accumulation of Okadaic Acid and Detoxifying Enzymes in the Digestive. . .
223
to S-D-lactoilglutathione by the GLO I activity. This S-D-lactoilglutathione is
subsequently hydrolyzed to D-lactate and glutathione (GSH) by GLO II enzyme.
Our results show an increase of GLO I activity with OA intoxication in both sexes
(Fig. 19.1d) with a statistically significant correlation in males (r: 0.370, p < 0.05)
(Table 19.1). This enzyme also shows a significant correlation with GR (r: 0.771,
p < 0.01) and GST (r: 0.737, p < 0.01) activities in males, and with CPR (r: 0.334,
p < 0.05) and GR (r: 0.557, p < 0.01) activities in females (Table 19.1). These
results are consistent with induction by OA of GLO I in Mytilus as also obtained
by Auriemma and Battistella (2004).
Other oxidative defence enzymes that seem to be related to the episodes of intoxication by OA in mussels are glutathione peroxidase (GPXtot) and catalase (CAT).
GPXtot activity increases in both sexes during intoxication, showing in females
a negative correlation with accumulated OA (r: 0.366, p < 0.01) (Fig. 19.1e;
Table 19.1) and positive one with CPR (r: 0.440, p < 0.01), GST (r: 0.608, p < 0.01)
and with GLO I (r: 0.312, p < 0.0) activities. In males its activity is only correlated
with GST (r: 0.430, p < 0.01) and GLO I (r: 0.412, p < 0.01) (Table 19.1). On the
other hand, CAT activity has no correlation with accumulated OA (Fig. 19.1f), but
shows significant correlation with CPR (r: 0.338, p < 0.0 5) and GST (r: 0.416,
p < 0.01) in males and with GPXtot (r: 0.317, p < 0.05) in females.
Despite the preliminary nature of this work, the results obtained suggest the
involvement of the microsomal monooxygenase enzymatic system dependent on
cytochrome P450 in the okadaic acid biotransformation in Mytilus galloprovincialis.
Moreover, the different enzymatic correlations in males and females seem to
indicate sexual differences in the metabolic pathways followed. However, to confirm
this and to define other possible enzymes and pathways involved in OA degradation
and elimination in mussels further studies will be required.
Acknowledgment The authors thank Antonio Antepazos and the fishermen of the “Antepazos I”,
who kindly provided the mussels used in this work. This work was supported by a grant from
Autonomous Galician Government (Ref. 2008/cp390) within the Strategic Action: EPITOX.
References
Aebi H (1984) Catalase in vitro. Methods Enzymol 105:121–126
Auriemma R, Battistella S (2004) Biochemical and histological alterations of Mytilus galloprovincialis digestive gland after exposure to okadaic acid and derivatives. Invertebr Survive J 1:66–71
Blanco J, Mari˜ no C, Mart´ ın H, Acosta CP (2007) Anatomical distribution of diarrhetic shellfish
poisoning (DSP) toxins in the mussel Mytilus galloprovinciallis. Toxicon 50:1011–1018
Bochetti R, Regoli F (2006) Seasonal variability of oxidative biomarkers, lysosomal parameters,
metallothioneins and peroxisomal enzymes in the Mediterranean mussel Mytilus galloprovincialis from Adriatic. Chemosphere 65:913–921
Borkovic SS, Saponjic JS, Pavlovic SZ, Blagojevic DP, Milosevic SM, Kovacevic TB, Radojicic
RM, Spasic MB, Zikic RV, Saicic ZS (2005) The activity of antioxidant defense enzymes in
the mussel Mytilus galloprovincialis transplanted into the northwest Mediterranean Sea. Comp
Biochem Physiol 138C:411–427
223
to S-D-lactoilglutathione by the GLO I activity. This S-D-lactoilglutathione is
subsequently hydrolyzed to D-lactate and glutathione (GSH) by GLO II enzyme.
Our results show an increase of GLO I activity with OA intoxication in both sexes
(Fig. 19.1d) with a statistically significant correlation in males (r: 0.370, p < 0.05)
(Table 19.1). This enzyme also shows a significant correlation with GR (r: 0.771,
p < 0.01) and GST (r: 0.737, p < 0.01) activities in males, and with CPR (r: 0.334,
p < 0.05) and GR (r: 0.557, p < 0.01) activities in females (Table 19.1). These
results are consistent with induction by OA of GLO I in Mytilus as also obtained
by Auriemma and Battistella (2004).
Other oxidative defence enzymes that seem to be related to the episodes of intoxication by OA in mussels are glutathione peroxidase (GPXtot) and catalase (CAT).
GPXtot activity increases in both sexes during intoxication, showing in females
a negative correlation with accumulated OA (r: 0.366, p < 0.01) (Fig. 19.1e;
Table 19.1) and positive one with CPR (r: 0.440, p < 0.01), GST (r: 0.608, p < 0.01)
and with GLO I (r: 0.312, p < 0.0) activities. In males its activity is only correlated
with GST (r: 0.430, p < 0.01) and GLO I (r: 0.412, p < 0.01) (Table 19.1). On the
other hand, CAT activity has no correlation with accumulated OA (Fig. 19.1f), but
shows significant correlation with CPR (r: 0.338, p < 0.0 5) and GST (r: 0.416,
p < 0.01) in males and with GPXtot (r: 0.317, p < 0.05) in females.
Despite the preliminary nature of this work, the results obtained suggest the
involvement of the microsomal monooxygenase enzymatic system dependent on
cytochrome P450 in the okadaic acid biotransformation in Mytilus galloprovincialis.
Moreover, the different enzymatic correlations in males and females seem to
indicate sexual differences in the metabolic pathways followed. However, to confirm
this and to define other possible enzymes and pathways involved in OA degradation
and elimination in mussels further studies will be required.
Acknowledgment The authors thank Antonio Antepazos and the fishermen of the “Antepazos I”,
who kindly provided the mussels used in this work. This work was supported by a grant from
Autonomous Galician Government (Ref. 2008/cp390) within the Strategic Action: EPITOX.
References
Aebi H (1984) Catalase in vitro. Methods Enzymol 105:121–126
Auriemma R, Battistella S (2004) Biochemical and histological alterations of Mytilus galloprovincialis digestive gland after exposure to okadaic acid and derivatives. Invertebr Survive J 1:66–71
Blanco J, Mari˜ no C, Mart´ ın H, Acosta CP (2007) Anatomical distribution of diarrhetic shellfish
poisoning (DSP) toxins in the mussel Mytilus galloprovinciallis. Toxicon 50:1011–1018
Bochetti R, Regoli F (2006) Seasonal variability of oxidative biomarkers, lysosomal parameters,
metallothioneins and peroxisomal enzymes in the Mediterranean mussel Mytilus galloprovincialis from Adriatic. Chemosphere 65:913–921
Borkovic SS, Saponjic JS, Pavlovic SZ, Blagojevic DP, Milosevic SM, Kovacevic TB, Radojicic
RM, Spasic MB, Zikic RV, Saicic ZS (2005) The activity of antioxidant defense enzymes in
the mussel Mytilus galloprovincialis transplanted into the northwest Mediterranean Sea. Comp
Biochem Physiol 138C:411–427