Abstract: With β-actin as reference genes and by means of the real-time fluorescence quantitative RT-PCR method, levels of mRNA expression of HSC70 and HSP70 in gill, mantle and digestive gland of Crassostrea hongkongensis exposed to NP varying in concentration (0, 0.01, 0.1, 1, 10, 100 and 300 μg•L^-1) were determined at 12, 24, 48, 96 and 192 h. Results show that 0.01 μg•L^-1 NP induced significantly expression of HSC70 and HSP70 mRNA in gill and disgestive gland(P<0.05). With rising NP concentration in treatment, the expression level increased gradually. Within a certain time period, 100 μg•L^-1 NP induced significantly a higher expression level than 300 μg•L^-1 NP did(P<0.05). When the expression of HSC70 gene in gill and digestive gland peaked at 96h, it did at 48h in mantle, and when the expression of HSP70 in gill peaked at 48h, it did at 24h in mantle and digestive gland. It is quite obvious that HSC70 and HSP70 genes in the oysters respond significantly to NP.

Key words: HSC70 gene, HSP70 gene, response, nonylphenol (NP), Crassostrea hongkongensis