Bioavailable metals and cellular effects in the digestive gland of marine limpets living close to shallow water hydrothermal vents

Bioavailability of heavy metals and their effects on the midgut cells of a phytopaghous insect inhabiting volcanic environments

“…Morphometric changes in digestive tissues have been used as common biomarkers for pollution exposure of anthropogenic and volcanic origin (Marigomez et al, 1996;Vega et al, 1989;Amaral et al, 2006a;Cunha et al, 2008). However, the present study shows that this trait is not reliable as a marker of the chronic metal exposure of P. unipuncta larvae, since the mean digestive epithelium thickness did not differ between both sites.…”

“…In contrast with heavy metal contents in soils and grass, larvae from the active volcanic environment presented higher concentrations of Cu, Mn, Rb and Zn, similarly to that observed by Cunha et al (2008) in the digestive gland of marine limpets from shallow water hydrothermal vents. Higher levels of Rb in organisms after volcanic exposure are not uncommon (Widom et al, 1997;Claude-Ivanaj et al, 2001;Durand et al, 2004), so the presence of Rb in samples from Água Azeda were expected, and thus the levels of this trace element could be used as a biomarker of exposure to volcanic environments, as previously suggested (Durand et al, 2004;Amaral et al, 2008).…”

“…Consequently, organisms living in such environment may be continually exposed to metals, either as particles or associated with gases (Hansell et al, 2006). The association between changes in the digestive epithelium and the occurrence of apoptosis under chronic metal and metalloid exposure, originated by volcanic activity, has been previously found in terrestrial (e.g., earthworms, and snails) and marine invertebrates (e.g., limpets) (Amaral and Rodrigues, 2005;Zaldibar et al, 2006;Cunha et al, 2008). Thus, it is important to look for organisms that can be used as biological indicators or sentinels for the presence of those pollutants under such conditions, and in which one can rapidly measure several biomarkers of exposure and/or effects.…”

“…Since the larval stages develop and feed usually on grass within a restricted area inside the pastures (Reis et al, 2003;Silva et al, 2003), these organisms, their food and inhabiting soils could be used to evaluate bioavailability and biotransference of trace metals in extreme environments of volcanic origin. Bearing this in mind, and since it is known that metals can promote and originate changes in the composition and diameter of digestive epithelia of several invertebrates that can be measured through variations in the mean radial epithelial thickness (Amaral et al, 2006a;Marigomez et al, 2006;Cunha et al, 2008), but also with apoptosis, another cellular response that may be triggered by metal stress. Apoptosis is involved in cell turnover, and has been suggested as a biomarker of the effect of bioavailable metals when its rates vary from normal (Amaral and Rodrigues, 2005;Cunha et al, 2008).…”

“…Bearing this in mind, and since it is known that metals can promote and originate changes in the composition and diameter of digestive epithelia of several invertebrates that can be measured through variations in the mean radial epithelial thickness (Amaral et al, 2006a;Marigomez et al, 2006;Cunha et al, 2008), but also with apoptosis, another cellular response that may be triggered by metal stress. Apoptosis is involved in cell turnover, and has been suggested as a biomarker of the effect of bioavailable metals when its rates vary from normal (Amaral and Rodrigues, 2005;Cunha et al, 2008). The present study aimed to determine whether larvae exposed and not exposed to volcanic activity show distinct metal body burdens, but also to analyze the effects of such metals on the midgut cell morphometry and apoptosis.…”