[The head regeneration ofLineus sanguineus Rathke (Nemertini) under the influence of actinomycin-D....

Fragments ofLineus sanguineus were incubated in seawater, which contained different concentrations of actinomycin-D (1.9 μg/ml, 0.95 μg/ml and 0.48 μg/ml). After 4, 5, 6 and 10 days the regenerates were studied by histological and histochemical methods (glycogen, glucose-6-phosphate-dehydrogenase and RNA). Corresponding to actinomycin-D concentration certain phases of regeneration are inhibited. The phases of proliferation are less sensitive to actinomycin-D than the phases of differentiation. If morphogenetic areas are inhibited, the normally demonstrable histochemical characteristics: accumulation of glycogen and later, the increase of G-6-P-DH activity and RNA concentration do not appear.