Chemical defence by mono-prenyl hydroquinone in a freshwater ciliate, Spirostomum ambiguum

Abstract

Several species of ciliates produce and accumulate low molecular weight toxic compounds in specialised membrane-bound ejectable organelles: extrusomes. These compounds can be used in predator–prey interaction for killing prey as well as for chemical defence. Here, we describe the isolation and characterisation of 2-(3-methylbut-2-enyl)benzene-1,4-diol(mono-prenyl hydroquinone), the extrusomal defensive toxin of the freshwater heterotrich ciliate Spirostomum ambiguum. The toxin was purified at homogeneity by RP-HPLC, and its structural characterisation was carried out through NMR and MS measurements. In vivo experiments involving S. ambiguum and Climacostomum virens in predator–prey interaction, and the analysis of cytotoxic activity of mono-prenyl hydroquinone on a panel of free-living freshwater ciliates, indicated that the toxin is very effective in S. ambiguum’s chemical defence

Phagotrophic Protist Diversity in the Groundwater of a Karstified Aquifer – Morphological and Molecular Analysis

“…As the highest trophic level in the karstified aquifer system, metazoa related to Stenostomum feed on protists and microorganisms (Buonanno ; Buonanno et al. ) while Plectidae are preferentially bacterivorous (Bert et al. ).…”

Antimicrobial activity of the protozoan toxin climacostol and its derivatives

“…These substances include keronopsin isolated from Pseudokeronopsis rubra Ehrenberg, 1836 (Höfle et al 1994), euplotins (Dini et al 1993;Guella et al 1994), raikovenal (Guella et al 1995;Rosini et al 1998) and epoxyfocardin (Guella et al 1996) from Euplotes species, blepharismin from Blepharisma japonicum Suzuki, 1954(Gioffrè et al 1993Checcucci et al 1997), stentorin from Stentor coeruleus Ehrenberg, 1830 (Tao et al 1993;Cameron et al 1995), spirostomin from Spirostomum teres Claparede et Lachmann, 1858(Sera et al 2006, maristentorin from Maristentor dinoferus Lobban et al, 2002(Mukherjiee et al 2006, climacostol from Climacostomum virens Ehrenberg, 1833 (Miyake et al 2003), and monoprenyl-hydroquinone from Spirostomum ambiguum Ehrenberg, 1835 (Buonanno et al 2012). Interestingly, due to its antimicrobial and pro-apoptotic activity in some tumor cell lines, the sesquiterpenoid euplotin C was recently proposed for the design of new drugs (Savoia et al 2004;Cervia et al 2006Cervia et al , 2007.…”

Phytoplankton growth inhibited by the toxic and bacterivorous ciliate Uronema marinum (Protozoa, Ciliophora)

“…Chemicals exchanged via cell-to-cell contact, by ciliates of the genus Euplotes for instance, inhibit the growth of competitive ciliates (Guella et al 2010). The freshwater ciliate Spirostonum ambi gu um uses toxins as a chemical defence, but it is suggested that the chemicals are also used to limit the presence of competitors (Buonanno et al 2012).…”

“…Chemicals exchanged via cell-to-cell contact, by ciliates of the genus Euplotes for instance, inhibit the growth of competitive ciliates (Guella et al 2010). The freshwater ciliate Spirostonum ambi gu um uses toxins as a chemical defence, but it is suggested that the chemicals are also used to limit the presence of competitors (Buonanno et al 2012).A possible function of the presumed Uro ne ma marinum toxin is to kill algal or perhaps other planktonic cells in order to release dissolved organic matter (DOM) in the water, which can then serve as a substrate for heterotrophic bacteria. More DOM means more bacteria and because U. marinum is assumed to be mainly bacterivorous, an increase in bacterial abundance would be beneficial for the ciliate.…”

“…Additionally, it would be interesting to investigate the cellular localization of the extrusomes containing the toxin and the physiological mechanism of their discharge. Comparable studies have been performed on the chemical de fence of heterotrich ciliates (Miyake et al 2003, Buonanno et al 2012. Toxin concentrations as well as fluxes of carbon from phytoplankton to bacteria and Uronema should be quantified.…”