|Budget Amount *help
¥3,300,000 (Direct Cost : ¥3,300,000)
Fiscal Year 2000 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1999 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1998 : ¥1,700,000 (Direct Cost : ¥1,700,000)
We investigated the steps during the foot formation (basal disk cell differentiation) in hydra. First, in the animals (Pelmatohydra robusta) which were amputated their feet in the peduncle region, the foot regeneration advanced in the position dependent manner, but the regeneration rate in the animals which were amputated their feet in the gastric column region was random. Second, both the upper and the lower peduncle tissues differentiated into the basal disk cells when they were located at the basal end of the regenerating animals after amputation of feet at the either regions. They could also differentiate into basal disk cells when they were transplanted to the body column. However, explants from the upper region of the peduncle did not differentiate into the basal disk cells while explants from the lower peduncle did. In some cases of these experiments, all of the ectodermal epithelial cells of the lowest peduncle explant differentiated into basal disk cells. The lowest part of the peduncle, whether it was explanted or was located at the basal end of a foot amputated animal, began to differentiate into the basal disk cells immediately (only four hours) after the removal of original basal disk. These results suggest that the body column and the peduncle is in different states each other from the view of basal disk cell differentiation. Another state difference between the upper peduncle and the lower peduncle is also suggested. We, therefore, concluded that in the upper peduncle ectodermal epithelial cells have been specified their fate of differentiation but are not yet determined to basal disk cells, whereas in the lower peduncle they have been determined already but do not differentiate basal disk cells, yet.
Now, we are studying roles of apoptosis in the basal disk size regulation mechanism, and trying to detect apoptosis in Hydra by TUNEL method. We are also trying to isolate Caspase gene from P.robusta and have isolated cDNA fragment.