Summary
A carnivorous ciliate,Didinium nasutum, captures a prey,Paramecium spp., by discharging extrusomes (i.e., toxicysts) from the proboscis. To directly examine the role of Ca2+ for the discharge, we injected Ca2+ intoD. nasutum. Injection of Ca2+ evoked discharge of toxicysts, if the site of the injection was the periphery region of the proboscis. After the discharge,D. nasutum, opened the proboscis and swallowed the discharged toxicysts. These observations demonstrate that a rise in cytoplasmic Ca2+ level is an actual cause of toxicyst discharge inD. nasutum.
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Abbreviations
- EGTA:
-
ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid
- FITC:
-
fluorescein isothiocyanate
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Iwadate, Y., Katoh, K., Kikuyama, M. et al. Ca2+ triggers toxicyst discharge inDidinium nasutum . Protoplasma 206, 20–26 (1999). https://doi.org/10.1007/BF01279249
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DOI: https://doi.org/10.1007/BF01279249