Fle. Chu et al., Cellular responses and disease expression in oysters (Crassostrea virginica) exposed to suspended field - contaminated sediments, MAR ENV RES, 53(1), 2002, pp. 17-35
Exposure of oysters to water soluble fractions derived from field-contamina
ted sediments (FCS) containing predominantly lower molecular weight organic
aromatic compounds, has been previously demonstrated to enhance pre-existi
ng infections caused by the protozoan parasite, Perkinsus marinus (Dermo),
and the prevalence of experimentally induced infections. To further explore
the role of pollution on the onset and progression of disease, effects of
suspended FCS from an estuarine creek in Virginia, USA, dominated by higher
molecular weight polycyclic aromatic hydrocarbons (PAHs) on cellular respo
nses and Dermo disease expression in oysters (Crassostrea virginica) were e
xamined. Sediments were collected from a PAH polluted estuarine creek in Vi
rginia, USA. To test effects on cellular response, oysters from Maine were
exposed daily to 0, 1.0, 1.5, or 2.0 g suspended FCS (corresponding to 0, 7
0.2, 105, or 140 mug PAHs, respectively) for 5, 10, 20, and 40 days. Hemocy
te activities and plasma lipid, protein and lactate dehydrogenase (LDH) lev
els were then measured. Exposure stimulated neutral red uptake, MTT reducti
on, and H-3-leucine incorporation in oyster hemocytes at various exposure t
imes, but did not affect the plasma protein, lipid and LDH levels. To test
effects on Dermo expression, oysters from a Dermo enzootic area, with an in
itial estimated infection prevalence of 39%, were exposed daily to 0, 1.0,
1.5, or 2.0 g suspended FCS (corresponding to 0, 75.0, 113, or 150 mug PAHs
, respectively) for 30 days. Exposure enhanced disease expression in oyster
s. However, no significant change was noted in any measured cellular or hum
oral parameters. (C) 2001 Elsevier Science Ltd. All rights reserved.