TY - JOUR
T1 - Significance of metallothioneins and lysosomes in cadmium toxicity and homeostasis in the digestive gland cells of mussels exposed to the metal in presence or absence of phenanthrene
AU - Viarengo, A.
AU - Moore, M. N.
AU - Mancinelli, G.
AU - Mazzucotelli, A.
AU - Pipe, R. K.
N1 - Funding Information:
cellular stress, was significantly reduced (P < 0-01) in mussels exposed to Cd for 9 days (Table 1), but returned to the control value in the digestive cells of mussels transferred to uncofitaminated seawater for 28 days (Table l), when most of the cytosolic Cd was bound to thioneins. These data demonstrate the importance of metallothionein induction in the alleviation of the cytotoxic effects provoked by high levels of metal accumulation, v This experiment was intended to clarify the reasons for the long half-life of Cd and demonstrated that lysosomes were not able to eliminate Cd either bound to insoluble thionein polymers or to lipid peroxidation products such as lipofuscin. 8 The absence of both types of mechanisms was confirmed by the lack of any lysosomal cytochemical reaction products for -SH rich protein (Shikata-orcein reaction) 3 or lipofuscin (Schmorl reaction). 9 The absence of activity of these two important mechanisms of metal sequestration and elimination via excretion of the residual bodies 3's is in agreement with the persistent presence of the metal in the digestive gland of the mussels. Finally, the results presented also demonstrate that the simultaneous exposure of mussels to Cd and phenanthrene, an established lysosomal destabiliser, 6 does not significantly alter the accumulation of the metal or the mechanisms of homeostasis (Table 1). This indicates that the role of lysosomes in cadmium elimination or sequestration is probably minimal as opposed to the situation with copper. 3 Some of this work forms part of the programme of the Cellular Processes Research Group of the Institute for Marine Environmental Research, a component of the Natural Environment Research Council. The work was partly funded by Contract No. EI4140RX from the Water Research Centre (WRC Environment).
PY - 1985
Y1 - 1985
N2 - Metallothioneins and lysosomes are known to be involved in cellular detoxication and sequestration of certain metals1-3 and both have been identified in this role in elimination of copper from marine mussels (Mytilus edulis/galloprovincialis).3 Cadmium (Cd), however, has been shown to persist in the cells of the digestive gland for long periods with only minimal elimination. An experiment was designed to test the effects of Cd on the fragility of lysosomal membranes in the digestive cells as a measure of cellular injury,4,5 metallothionein content of the digestive gland and cadmium concentration in this organ. Phenanthrene was used also to destabilise lysosomal membranes6 in order to test if increased lysosomal fragility interfered with cadmium metabolism and detoxication. The results demonstrated that Cd induced metallothionein synthesis and that elimination of Cd was minimal after 28 days in clear seawater. Lysosomal fragility was initially increased but this effect was soon reversed, even with continued exposure to Cd. The lysosomal destabiliser, phenanthrene, did not appear to affect accumulation of Cd or levels of metallothionein.
AB - Metallothioneins and lysosomes are known to be involved in cellular detoxication and sequestration of certain metals1-3 and both have been identified in this role in elimination of copper from marine mussels (Mytilus edulis/galloprovincialis).3 Cadmium (Cd), however, has been shown to persist in the cells of the digestive gland for long periods with only minimal elimination. An experiment was designed to test the effects of Cd on the fragility of lysosomal membranes in the digestive cells as a measure of cellular injury,4,5 metallothionein content of the digestive gland and cadmium concentration in this organ. Phenanthrene was used also to destabilise lysosomal membranes6 in order to test if increased lysosomal fragility interfered with cadmium metabolism and detoxication. The results demonstrated that Cd induced metallothionein synthesis and that elimination of Cd was minimal after 28 days in clear seawater. Lysosomal fragility was initially increased but this effect was soon reversed, even with continued exposure to Cd. The lysosomal destabiliser, phenanthrene, did not appear to affect accumulation of Cd or levels of metallothionein.
UR - http://www.scopus.com/inward/record.url?scp=0022372767&partnerID=8YFLogxK
U2 - 10.1016/0141-1136(85)90076-5
DO - 10.1016/0141-1136(85)90076-5
M3 - Article
SN - 0141-1136
VL - 17
SP - 184
EP - 187
JO - Marine Environmental Research
JF - Marine Environmental Research
IS - 2-4
ER -
