The ultrastructure of the damaged and regenerating renal epithelium of goldfish Carassius auratus exposed to hexachlorobutadiene (HCBD) was examined. As in mammals, the target organelles for HCBD-induced nephrotoxicity are the mitochondria. Extensively swollen mitochondria appeared in proximal segments P2 and P3 within 12 h of HCBD exposure. By 1 week, swollen mitochondria were also present in P 1 epithelial cells. Initially, regenerating epithelial cells in the injured nephrons appeared insensitive to the toxicity. Once they developed more differentiated characteristics, they also developed swollen mitochondria. Newly formed developing nephrons appeared several weeks following toxicant exposure. These also appeared resistant to the toxicity until they became more differentiated. The inhibitor aminooxyacetic acid protected the epithelium from the toxicity, indicating a possible role for cysteine-conjugate β-lyase in the bioactivation of HCBD metabolites in the goldfish.

Larval striped bass Morone saxatilis were exposed to three hardness (40, 100, and 160 mg/L as CaCO3 equivalents) and two NaCl salinity (2.0 and 3.0‰) treatments for 10 d in a modified flow-through system. Salinity had a greater effect on larval survival than did hardness over the ranges tested. Elevated NaCl salinity appeared to be detrimental; larvae exposed to 3.0‰ NaCl had significantly higher mortality than did those exposed to 2.0‰ NaCl. At 2.0‰ salinity, hardness does not appear to play an important role in larval survival (probability of survival > 0.70). At 3.0‰ salinity, mortality was greatest at hardness levels of 40 and 100 mg/L (probability of survival = 0.06 and 0.01, respectively), whereas at 160 mg/L, mortality was reduced (probability of survival = 0.39). The reason for this response is not clear, although there may be an optimal ratio of different ions contributing to total salinity. By comparison, other studies in which diluted seawater was used indicated that salinities of 0.5-10.0‰ enhance the survival of striped bass larvae.

Comparisons were made of attachment and viability of rainbow trout (Salmo gairdneri) hepatocytes in short-term (2 days), primary culture on plastic, collagen-coated or extracellular matrix (ECM) coated dishes. Hepatocyte isolation routinely yielded cells with good viability (96%). Cells plated on ECM attached with high efficiency (93%) in contrast to cells cultured on plastic or collagen (∼20%). The cells plated on ECM flattened out and formed monolayers, while the cells on plastic and collagen rounded up and formed multi-cell aggregates in suspension. Viability of cells in all substrates remained high over the 2 day culture period. ECM is the first substrate to support trout-hepatocyte attachment in primary culture. Differentiated liver function was maintained in cells cultured on ECM as evidence by the induction of tyrosine aminotransferase by hydrocortisone (200%).