Impacts at the cellular level were evaluated in shore crab haemocytes by assessing membrane integrity (cellular viability) and immune function (phagocytosis) which were negatively impacted (decreased cellular viability and phagocytosis) by contaminant exposure. However, only those crabs exposed to pyrene during lab exposures showed significant decreases in cellular viability and phagocytosis index. In C. maenas, lysosomes are found within the hyaline
regorafenib which are important in terms of phagocytic activity (the innate immune function in crustaceans) ( Ratcliffe and Rowley, 1979). There are ca. 2.5 × 108 circulating haemocytes in C. maenas, and around 80% of these cells are capable of phagocytosis, thereby underscoring the phagocytic ability of this species ( Smith and Ratcliffe, 197
cool . Pyrene is biotransformed by shore crabs into more hydrophilic compounds for excretion by phase I metabolism ( Dam et al., 2006), however, PAHs exert their toxic effect by either the parent compound or subsequently, during metabolism resulting in production of reactive oxygen species (ROS) ( Livingstone, 1991 and Livingstone, 199
cool . Resulting toxic effects in shore crab haemocytes include, membrane destabilisation and immune function alteration ( Dissanayake et al., 2008a and Dissanayake et al., 2008b). Although, significant impact at the cellular level was only observed in laboratory pyrene-exposed individuals, it provides an insight into the mechanism of acute contaminant exposure. Pyrene, like other PAHs which are polar hydrophobic contaminants, are sequestered in the lysosomal compartment of cells. Lysosomal damage arising from the accumulation of contaminants and formation of oxyradicals causes increased membrane permeability and subsequent release of
acid hydrolases into the cytoplasm, resulting in cellular damage/cell death (as shown by decreased cellular viability) and, subsequently, resulting in a reduced immune function (as shown by reduced phagocytic ability) ( Lowe et al., 1995, Grundy et al., 1996a and Grundy et al., 1996b).
