Action mechanisms of the secondary metabolite euplotin C: signaling and functional role in Euplotes.

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.

Identification and characterization of a 38 kDa glycoprotein functionally associated with mating activity of Paramecium primaurelia.

In Paramecium primaurelia mating interactions take place immediately after mixing mating-competent cells of opposite mating types. The cells clump in clusters (mating reaction) and then separate in pairs. Previous results have shown that sialic acid-containing glycoconjugates are present on the cell surface and are involved in mating-cell pairing.

Effects of xenobiotic compounds on the cell activities of Euplotes crassus, a single-cell eukaryotic test organism for the study of the pollution of marine sediments.

It is now widely accepted that assays with protists are relevant to be exploited for the study of environmental modifications due to the presence of xenobiotic compounds. In this work, the possibility of utilizing Euplotes crassus, an interstitial marine ciliate, for the pre-chemical screening of estuarine and coastal sediments was evaluated. For this purpose, the effects of exposure to pollutants were tested on the cell viability, fission rate and lysosomal membrane stability of E.

Effects of organophosphate compounds on a soil protist, Colpoda inflata (Ciliophora, Colpodidae).

Many investigations on protists indicate that they play an important role in agricultural soils. We have tested the effects of three organophosphate (OP) pesticides, basudin, cidial, and fenix, on the soil ciliate Colpoda inflata, and examined its viability, fission rate, ability to excyst and extrude macronuclear chromatin into cytoplasm. Exposure to these OPs caused a dose-dependent effect on cell viability, and significantly reduced the mean fission rate at a concentration of 1/10(5) v/v.

Detection of NADPH-diaphorase activity in Paramecium primaurelia.

Recently, we showed that Paramecium primaurelia synthesizes molecules functionally related to the cholinergic system and involved in modulating cell-cell interactions leading to the sexual process of conjugation. It is known that nitric oxide (NO) plays a role in regulating the release of transmitter molecules, such as acetylcholine, and that the NO biosynthetic enzyme, nitric oxide synthase (NOS), shows nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity. In this work, we detected the presence of NADPH-d activity in P.

Effects of a 50 Hz magnetic field on Dictyostelium discoideum (Protista).

Some studies have demonstrated that a few biological systems are affected by weak, extremely low frequency (ELF) electromagnetic fields (EMFs), lower than 10 mT. However, to date there is scanty evidence of this effect on Protists in the literature. Due to their peculiarity as single-cell eukaryotic organisms, Protists respond directly to environmental stimuli, thus appearing as very suitable experimental systems.

Cholinesterase activity and effects of its inhibition by neurotoxic drugs in Dictyostelium discoideum.

Recently, we found acetylcholinesterase (AChE) activity in the ciliate protozoan Paramecium primaurelia. As in the slime mould Dictyostelium discoideum the presence of a serine esterase was found with strong sequence identity to Torpedo AChE, we extended to D. discoideum the investigation on the characterization and possible functions of cholinesterases (ChEs).