TY - JOUR
T1 - Action mechanisms of the secondary metabolite euplotin C
T2 - Signaling and functional role in Euplotes
AU - Trielli, Francesca
AU - Cervia, Davide
AU - Di Giuseppe, Graziano
AU - Ristori, Chiara
AU - Kruppel, Thomas
AU - Burlando, Bruno
AU - Guella, Graziano
AU - Viarengo, Aldo
AU - Bagnoli, Paola
AU - Delmonte Corrado, Maria Umberta
AU - Dini, Fernando
PY - 2008/9
Y1 - 2008/9
N2 - Among secondary metabolites, the acetylated hemiacetal sesquiterpene euplotin C has been isolated from the marine, ciliated protist Euplotes crassus, and provides an effective mechanism for reducing populations of potential competitors through its cytotoxic properties. However, intracellular signaling mechanisms and their functional correlates mediating the ecological role of euplotin C are largely unknown. We report here that, in E. vannus (an Euplotes morphospecies that does not produce euplotin C and shares with E. crasssus the same interstitial habitat), euplotin C rapidly increases the intracellular concentration of both Ca2+ and Na+, suggesting a generalized effect of this metabolite on cation transport systems. In addition, euplotin C does not induce oxidative stress, but modulates the electrical properties of E. vannus through an increase of the amplitude of graded action potentials. These events parallel the disassembling of the ciliary structures, the inhibition of cell motility, the occurrence of aberrant cytoplasmic vacuoles, and the rapid inhibition of phagocytic activity. Euplotin C also increases lysosomal pH and decreases lysosomal membrane stability of E. vannus. These results suggest that euplotin C exerts a marked disruption of those homeostatic mechanisms whose efficiency represents the essential prerequisite to face the challenges of the interstitial environment.
AB - Among secondary metabolites, the acetylated hemiacetal sesquiterpene euplotin C has been isolated from the marine, ciliated protist Euplotes crassus, and provides an effective mechanism for reducing populations of potential competitors through its cytotoxic properties. However, intracellular signaling mechanisms and their functional correlates mediating the ecological role of euplotin C are largely unknown. We report here that, in E. vannus (an Euplotes morphospecies that does not produce euplotin C and shares with E. crasssus the same interstitial habitat), euplotin C rapidly increases the intracellular concentration of both Ca2+ and Na+, suggesting a generalized effect of this metabolite on cation transport systems. In addition, euplotin C does not induce oxidative stress, but modulates the electrical properties of E. vannus through an increase of the amplitude of graded action potentials. These events parallel the disassembling of the ciliary structures, the inhibition of cell motility, the occurrence of aberrant cytoplasmic vacuoles, and the rapid inhibition of phagocytic activity. Euplotin C also increases lysosomal pH and decreases lysosomal membrane stability of E. vannus. These results suggest that euplotin C exerts a marked disruption of those homeostatic mechanisms whose efficiency represents the essential prerequisite to face the challenges of the interstitial environment.
KW - Action potentials
KW - Cation homeostasis
KW - Ciliated protists
KW - Lysosomes
KW - Marine microorganisms
KW - Oxidative stress
KW - Phagocytosis
KW - Sesquiterpenoids
UR - http://www.scopus.com/inward/record.url?scp=54249165439&partnerID=8YFLogxK
U2 - 10.1111/j.1550-7408.2008.00335.x
DO - 10.1111/j.1550-7408.2008.00335.x
M3 - Article
SN - 1066-5234
VL - 55
SP - 365
EP - 373
JO - Journal of Eukaryotic Microbiology
JF - Journal of Eukaryotic Microbiology
IS - 5
ER -