Effects of Starvation and Resumption of Feeding on the Cell Populations of Hydra oligactis

In steady state Hydra, one group of stem cell derived cell types, nematocytes, are regularly turned over due to feeding. The effects of removal of this normal physiological stimulus to cell turnover (by starvation) and its subsequent reimposition (by resumption of feeding) on the population dynamics of Hydra cell types was investigated. Starvation resulted in marked alterations in both the nerve and nematocyte populations. Upon resumption of feeding the regulatory activities necessary to restore steady state cell population proportions appear to be initiated, although the temporal expression of these controls is unique to each cell type.