Protistology 6 (4) 245–250 (2010/11) |
Encystment-inducing factor “starvation” in ciliated protozoan Colpoda cucullus |
Yukari Otani and Tatsuomi Matsuoka Institute of Biological Science, Faculty of Science, Kochi University, Kochi, Japan Summary “Starvation” is known to be a common factor in encystment induction among a number of protozoans. Encystment induction by starvation may be responsible for consumption of encystment-suppressing nutrient molecules and/or their metabolic products. Encystment of Colpoda cucullus was suppressed and cells temporarily proliferated as a result of addition of D-glucose in the surrounding medium, whereas such encystment suppression and cell proliferation were cancelled in the presence of phlorizin, an inhibitor of D-glucose uptake. The results suggest that D-glucose or its metabolic products may affect the intracellular signaling pathway responsible for the encystment induction. When ATP synthesis was blocked by CCCP, oligomycin, or NaN3, the encystment suppression by D-glucose tended to be canceled. It is possible that final metabolic products of D-glucose including ATP, might be related to the suppression of encystment induction. Key words: Colpoda, encystment suppression, D-glucose, phlorizin, nutrients, starvation Address for correspondence: Tatsuomi Matsuoka. Institute of Biological Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan; e-mail: matsuok@cc.kochi-u.ac.jp |
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