Sublethal effects of ethylene dibromide on wound healing and morphogenesis in Hydra oligactis.

Morphogenetic activity (budding region regeneration, foot regeneration, tentacle regeneration, spikes, separation, and waist) was observed in Hydra oligactis with two tandemly arranged gastric regions (2g hydras) following exposure to a commercial ethylene dibromide (EDB) mixture. First-stage budding hydras were selected for this study. Animals were deprived of food 24 h prior to grafting and observed at 24, 48, and 72 h after grafting. The artificial pond water (APW) group was not treated with any chemicals prior to grafting. The acetone/APW group was pre-exposed to a concentration of 20 mg/L of acetone/APW 24, 48, and 72 h prior to grafting and observed at 24 h intervals for a three-day period. The EDB: acetone/APW group was exposed to a mixture containing 5 mg/L of EDB and 15 mg/L acetone for 24, 48, and 72 h prior to grafting and observed at 24-hr intervals for three days. All animals were incubated at 19 +/- 2 degrees C. Ethylene dibromide caused a significant decrease in 2 degrees foot regeneration at the 72 h observation interval for animals pre-exposed to EDB for 48 and 72 h. There was also a significant correlation between pre-exposure and a decrease in the number of 2 degrees feet regenerated. Tentacle regeneration was significantly suppressed following a 24-h pre-exposure to EDB. Waists at the graft border significantly increased at the 48 and 72 h observation times and separation of the graft border appeared at 72 h after grafting following 72 h pre-exposure of the animals to the chemical.