Simultaneous recording of cytosolic Ca2+ levels inDidinium andParamecium during aDidinium attack onParamecium

摘要: The carnivorous ciliateDidinium nasutum captures prey such asParamecium by discharging extrusomes, known as toxicysts, while the attackedParamecium defensively discharges trichocysts. Several authors have suggested that both discharges, toxicysts ofDidinium and trichocysts ofParamecium, are evoked rise in cytosolic Ca2+ level each cell. However, these putative increases levels not yet been recorded simultaneously cells during aDidinium attack onParamecium. We injected fluorescent indicator Ca-Green 1 dextran into bothDidinium andParamecium, observed asDidinium attackedParamecium. When aParamecium came contact with theDidinium proboscis, showed a significant basal portion of proboscis. One video frame (33 ms) after onset inDidinium, theParamecium also an increase Ca2+. This is first simultaneous recording changes predator-prey interaction ciliates. possible roles discussed relation to discharge defensive behavior ofParamecium.