| Popis: |
Salinity acclimation of the euryhaline ciliate Paramecium calkinsi evaluated by swimming velocity was accomplished within four to five days. In two series of the main experiment, acclimation continued for two and three days when actinomycin D (an inhibitor of DNA-dependent RNA polymerase) was added after various periods of the ciliate incubation at a different salinity (0, 3, 6, and 24 h). Experimental results indicate that the inhibitory effect of actinomycin D on salinity acclimation of P. calkinsi is manifested only within the first day of the ciliate incubation in an altered environment; by the end of this period, their swimming velocity becomes similar to the control one (acclimation in the absence of the inhibitor). Thus, the expression of genes associated with salinity acclimation in the paramecium is largely completed within the first day, while acclimation continues for at least 4–5 days. We propose that the acclimation-competent species possess a correspondingly more complex genetic program. |
