STRESS PROTEIN EXPRESSION IN AMPELISCA-ABDITA (AMPHIPODA) EXPOSED TO SEDIMENTS FROM SAN-FRANCISCO BAY

Stress proteins (heat shock proteins, hsps) form part of the cellular protein repair system, and are induced by a wide variety of stressors. To determine their suitability as tools for assessing sublethal sedim ent toxicity, we measured levels of members of the stress protein fami lies hsp60 and hsp70 in benthic estuarine amphipods (Ampelisca abdita) exposed to sediments from .23 different sampling sites in San Francis co Bay for 10 d. Concentrations of sediment-associated xenobiotics wer e determined Per cent survival was recorded and surviving animals were analysed for stress proteins using western blotting techniques. An in verse correlation (r(2)=0.44) was seen between amphipod survival and h sp64 levels, and hsp64 levels were positively correlated with concentr ations of total polycyclic aromatic hydrocarbons (PAHs) (r(2)=0.5). Pr incipal component analysis revealed that amphipod mortality was linked to a combination of several PAHs (phenanthrene, fluoranthene, pyrene, benzo(a)pyrene) and di-n-butylphthalate at southern San Francisco Bay sites. At northern San Francisco Bay sites, negative correlations wer e found between hsp64 levels and organotin compounds (MBT, DBT, TBT), and between hsp71 levels and the PAHs, benzo(b,k)fluoranthene and benz o(G,H,I)perylene, suggesting an inhibitory effect of these compounds o n stress protein expression. (C) 1998 Elsevier Science Ltd. All rights reserved.