Biosynthesis of DNA and cell surface macromolecules with sugar residues by developing Hydra 'embryo' cultured in the presence of vinblastine

초록

The effect of vinblastine on synthesis of DNA and surface glycoproteins in the aggregate regeneration of Hydra attenuata in vitro were investigated from its beginning to 60 hours of development. 〔³H〕 thymidine incorporation into DNA was increased from 24 hours of development particularly after 36 hours and proceeded the elaboration of buds. Although nuclear incorporation of labeled materials occurred evenly over the both layers of embryo, labeled cells were more concentrated at the early developing buds where interstitial cells are primary cell type. In the presence of vinblastine, the interstitial cells failed to increase in number and the epithelial cells failed to maintain their sheetlike arrangement and attachments and the results of a combined autoradiographic study and biological data demonstrated that vinblastine markedly inhibits the incorporation and depresses the DNA synthesis, that is, the reduced amount of labeled DNA in vinblastine treated embryo was due to a lack of incorporation rather than an inability to pick up the labeled materials from the medium. And inhibition of the DNA synthesis would be more likely to prevent cells from entering prophase, rather than to arrest them in metaphase. The binding of 〔³H〕 Concanavalin A to the surface macromolecules was also reduced similar to the pattern of DNA synthesis by prior vinblastine treatment. It may be considered chat the reduction of surface macromolecules could be related to the depressed DNA synthesis and accounted for the cellular detachment, consequent disorganization of histoarchitecture and dissociation of embryo by vinblastine.

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