Abstract
Heavy metals such as mercury (Hg) pose a significant health hazard through
bioaccumulation and biomagnification. By penetrating cell membranes, heavy metal
ions may lead to pathological conditions. Here we examined the responses of
Ammonia parkinsoniana, a benthic foraminiferan, to different concentrations of Hg in
the artificial sea water. Confocal images of untreated and treated specimens using
fluorescent probes (Nile Red and Acridine Orange) provided an opportunity for
visualizing the intracellular lipid accumulation and acidic compartment regulation. With
increased Hg over time, we observed an increased number of lipid droplets, which may
have acted as a detoxifying organelle where Hg is sequestered and biologically
inactivated. Further, Hg seems to promote the proliferation of lysosomes both in terms
of number and dimension that, at the highest level of Hg, resulted in cell death. We
report, for the first time, the presence of Hg within the foraminiferal cell: at the basal
part of pores, in the organic linings of the foramen/septa, and as cytoplasmic
accumulations.
