World Congress of Malacology Antwerp ... - Unitas Malacologica

mussels showed elevated levels for GPx and CAT activities at any sampling time. In digestive gland,
LS mussels exhibited equal or higher levels of antioxidant activities than HS mussels for the
reference site; in the polluted site a reversion of the patterns for GPx and GRd activities and greater
levels of SOD activity for both location were observed.
These results suggest that patterns of activities of antioxidant enzymes are affected by environmental
contamination as well as ecophysiological stresses imposed by tidal conditions and the combination
of the 2 parameters can induce a specific response of these activities.
Spatial differences and temporal variations of antioxidant defences in an intertidal population
of the blue mussel Mytilus edulis
Letendre, Julie; Olivier, Stéphanie; Poret, Agnès; Leboulenger, François; Durand, Fabrice
Laboratoire d’Ecotoxicologie – Milieux aquatiques, EA 3222, Université du Havre, France,
Email: julie.letendre@univ-lehavre.fr
During the tidal cycle, blue mussels undergo an alternation of tissular normoxia - strong hypoxia -
hyperoxia due to the decrease in oxygen availability in emersion and the sudden re-oxygenation when
recovery occurs. To deal with the oxidative and energetic stresses implied by this context, this specie
may have evolved acclimation capacities of its antioxidant defences. Activity levels of antioxidant
enzymes (Cu/Zn superoxyde dismutase, Cu/Zn SOD; catalase, CAT; glutathione peroxydase, GPx,
glutathione reductase, GRd, glutathione-S-transferase, GST) were measured in gills and digestive
gland of mussels sampled at high shore (HS, air exposure > 6h/12h) and low shore (LS, air exposure
< 2h/12h) of the intertidal zone of Yport (Normandie, France) over the entire tidal cycle. Whatever
the phase of the cycle, activity levels observed in both tissues were higher in individuals from high
shore in a +40 to 100% manner than in LS mussels. In gills, CAT (HS: +30%, LS: +56%), GRd (HS:
+44%, LS: +53%) and GST (LS: +44%) activities present a transient increase after 2h of emersion, in
the same way as the GRd activity in digestive gland (HS: +49%, LS: +70%). These results suggest
that a global pro-oxidant condition is imposed by the high ranges of the shore and consequently the
resident organisms exhibit an acclimation of antioxidant capacities according to this context.
Phylogenetic and structural aspects of chiton hemocyanins
Lieb, Bernhard 1 ; Streit, Klaus 1 ; Möller, Vanessa 1 ; Eernisse, Douglas J. 2
1. Institute of Zoology, University of Mainz, Müllerweg6, 55099 Mainz, Germany,
Email: lieb@uni.mainz.de; kstreit@uni.mainz.de; vmm79@gmx.de
2. Department of Biological Science, California State University, Fullerton, CA 92834 USA,
Email: deernisse@fullerton.edu
The phylogeny of chitons is mainly based on morphological characters and one molecular analysis.
According to the most current evidence from both of these approaches, Polyplacophora can be
subdivided into two major groups: Lepidopleurida and Chitonida. Our molecular study, based on a
hemocyanin sequence data set, also confirms this fundamental division. As supported by morphology
but in contrast to the sole molecular analysis by A. Okuzo and co-authors, our maximum likelihood
analysis supported Callochiton is supported as a basal ingroup taxon of the monophyletic Chitonida,
rather than as basal within Lepidopleurida, as in the molecular study. Within the relatively sparsely
represented remaining members of Chitonida that have been sampled to date, we also found strong
bootstrap support for the monophyly of one of the two suborders, Chitonina but not for the other,
Acanthochitonina. However, our results are at least compatible with the possible monophyly of
Acanthochitonina, and we found strong support for the monophyly of three of its families:
Mopaliidae, Acanthochitoninae and the Lepidochitonidae, even if we were not able to resolve the
relationships among these when only partial hemocyanin sequences were analyzed. We are therefore
increasing our taxon sampling continuously and moving toward combining these gene sequences
with other molecular and morphological evidence. Beside these phylogenetic results, we discovered
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