Dynamic transcriptional changes in benzo[a]pyrene exposed Hydra

Abstract

Transcriptional changes induced by Benzo[a]pyrene (BaP) acute toxicity in Hydra magnipapillata were evaluated. The median lethal concentrations of the animals (LC50) were determined to be 78.5 mg/L, 53.6 mg/L and 28.9 mg/L after exposure to BaP for 24 h, 48 h and 72 h, respectively. Morphological responses of hydra polyps to 50 mg/L of BaP by exposure time were observed. Differential gene expression profiling of the hydra polyp was performed with a cDNA microarray after exposure to 500 &micro g/L of BaP (about 1/100 of 48-h LC50) for 4 h, 12 h, 24 h, and 48 h to understand the changes in the acute toxicity by exposure time. The gene expression levels of molecular chaperones, antioxidative enzyme were altered at the early phase of the exposure. Transcription of the genes related to development, tumorigenesis, apoptosis, and necrosis were affected by the 4 h BaP exposure group. After 12 h exposure, developmental process, inflammatory process, calcium metabolism, innate immune and sodium-potassium channel related metabolism in hydra polyp seemed to be affected since the transcription of the genes which related to those biological process were induced or repressed by BaP exposure. Neurotransmission might be suppressed tumorigenesis and DNA damage might be induced in 24 h BaP exposed hydra group. Finally, carcinogenesis, DNA damage and protein degradation process seemed to be induced after 48 h exposure, on the other han BaP for 24 h, 48 h and 72 h, respectively. Morphological responses of hydra polyps to 50 mg/L of BaP by exposure time were observed. Differential gene expression profiling of the hydra polyp was performed with a cDNA microarray after exposure to 500 &micro g/L of BaP (about 1/100 of 48-h LC50) for 4 h, 12 h, 24 h, and 48 h to understand the changes in the acute toxicity by exposure time. The gene expression levels of molecular chaperones, antioxidative enzyme were altered at the early phase of the exposure. Transcription of the genes related to development, tumorigenesis, apoptosis, and necrosis were affected by the 4 h BaP exposure group. After 12 h exposure, developmental process, inflammatory process, calcium metabolism, innate immune and sodium-potassium channel related metabolism in hydra polyp seemed to be affected since the transcription of the genes which related to those biological process were induced or repressed by BaP exposure. Neurotransmission might be suppressed tumorigenesis and DNA damage might be induced in 24 h BaP exposed hydra group. Finally, carcinogenesis, DNA damage and protein degradation process seemed to be induced after 48 h exposure, on the other han