Analysis of morphogenetic mutants of hydra : III.Maxi andMini.

Minis have a doubling time of 2.4 days,maxis of 8 days.Minis regenerate head and foot 5 h faster thanmaxis.Minis have fewer tentacles (4.6) per head thanmaxis (6.1).Inmini the concentration of the head activator is equal to that inHydraattenuata, but the concentration of the head inhibitor is reduced (2-fold in the head, 1.2-fold in the body). The concentrations of the foot factors are normal.Minis respond likeHydra attenuata to head activator, foot activator and foot inhibitor, but they are less sensitive to head inhibitorInmaxi the concentration of the head activator is higher than inmini (5-fold in the head, 10-fold in the body) and that of the head inhibitor is also higher (4-fold in the head, 5-fold in the body). The concentration of the foot inhibitor is normal, that of the foot activator is doubled.Maxis are insensitive to added head activator and less sensitive to added head inhibitor and foot inhibitor. Their response to foot activator is normal.