Chemical Defence by Sterols in the Freshwater Ciliate Stentor polymorphus .
Federico BuonannoFrancesco TrentiGabriele AchilleAdriana VallesiGraziano GuellaClaudio OrtenziPublished in: Biology (2022)
Heterotrich ciliates typically retain toxic substances in specialized ejectable organelles, called extrusomes, which are used in predator-prey interactions. In this study, we analysed the chemical defence strategy of the freshwater heterotrich ciliate Stentor polymorphus against the predatory ciliate Coleps hirtus , and the microturbellarian flatworm Stenostomum sphagnetorum . The results showed that S. polymorphus is able to defend itself against these two predators by deploying a mix of bioactive sterols contained in its extrusomes. Sterols were isolated in vivo and characterized by liquid chromatography-mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR), as ergosterol, 7-dehydroporiferasterol, and their two peroxidized analogues. The assessment of the toxicity of ergosterol and ergosterol peroxide against various organisms, indicated that these sterols are essential for the effectiveness of the chemical defence in S. polymorphus.
Keyphrases
- magnetic resonance
- mass spectrometry
- liquid chromatography
- high resolution
- high resolution mass spectrometry
- randomized controlled trial
- systematic review
- oxidative stress
- palliative care
- molecular docking
- drinking water
- computed tomography
- gas chromatography
- magnetic resonance imaging
- simultaneous determination
- contrast enhanced
- gram negative
- solid state
- molecular dynamics simulations