The Physiology of Contractile Vacuoles
| Autor: | J. E. Padfield, J. A. Kitching, M. H. Rogers |
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| Rok vydání: | 1960 |
| Předmět: | |
| Zdroj: | Journal of Experimental Biology. 37:73-82 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.37.1.73 |
| Popis: | The suctorian Discophrya collini (Root) has been subjected to D2O–H2O mixtures containing up to 99·7 % D2O. In 25 % D2O or over there is a rapid but temporary shrinkage of the body. This shrinkage is difficult to estimate owing to the wrinkling of the body surface, but amounts to at least 10% in the undiluted (99.7%) D2O. During the period of temporary shrinkage the contractile vacuole ceases activity. Normal activity is resumed when the normal volume is regained. In concentrations of D2O too low to cause shrinkage there is a temporary fall in the rate of vacuolar output. Return to H2O leads to a brief but often very considerable rise in vacuolar output. It is concluded that D2O penetrates less rapidly than H2O. A difference of at least 10 % in the diffusion constants in the membrane would be required to explain our results. We cannot exclude this as unreasonable from our data, although an explanation based on differences in the equilibrium properties of D2O and H2O might also be invoked. |
| Databáze: | OpenAIRE |
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