[Somatic polyploidy in neurons of the gastropod molluscs. II. Dynamics of DNA synthesis in the process of postnatal growth of CNS neurons in Succineid snail].
A study was made of the age dynamics of polyploidization and dynamics of DNA synthesis in neuron cell nuclei during the postnatal growth of the gastropod pulmonate snail Succinea lauta. According to cytophotometrical results, the degree of polyploidization in neuron nuclei increases from young to adult individuals, varying from 2c to 16,384c. In the visceral complex, the maximum and medium ploidy values of the neuron nuclei are higher by almost 4-8 times than those in cerebral and pedal ganglia. The medium level of ploidy in adult snails increases by 5.7 times in the visceral complex of ganglia and by 4.1-4.2 times in the pedal and cerebral ganglia. According to 3H-thymidine autoradiography, DNA synthesis in neuron nuclei occurs during the whole life of the snail. In young individuals the neurons have the highest activity of DNA synthesis--the index of labeled nuclei of neurons making in total 50.2%. In older age, a steady decrease in the index of labeled nuclei is observed--in total to 35.8% and 7.0% in small and large adult snails, respectively. The state of summer hibernation completely stops DNA syntheses in neurons, but emergency from hibernation is accompanied by restoration of DNA syntheses.
Kirsanova
I A
IA
Far East State University, Vladivostok.
Anisimov
A P
AP
D000818:Animals; D001345:Autoradiography; D002454:Cell Differentiation / Q000502:physiology; D004261:DNA Replication; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D011123:Polyploidy; D012908:Snails / Q000166:cytology / Q000235:genetics* / Q000254:growth & development
Somaticheskaia poliploidiia v neĭronakh briukhonogikh molliuskov. II. Dinamika sinteza DNK v protsesse postnatal'nogo rosta neĭronov TsNS ulitki Iantarki.