Published 2010
| Version v1
Publication
Nitric oxide production is inhibited by xenobiotic compounds in the protozoan Paramecium primaurelia.
Contributors
Description
The notable increase in agricultural and industrial activities over the last decades has caused a
considerable increase in anthropogenic waste and, consequently, the presence of pollutants in both
water and sediments. For this reason, there is great interest in identifying alternative models and
bioassays complying with the 3Rs strategy (aimed at Reducing, Refining and Replacing tests on
vertebrate organisms in toxicological studies). Protozoa seem to be well suited to this strategy and it is
widely accepted that assays with protozoa are relevant to the study of environmental modifications due
to the presence of xenobiotic compounds.
Recently, we detected the presence of nitric oxide synthase (NOS)-related NADPH-diaphorase activity
and neuronal NOS-relatedmolecules, immunologically recognized by the anti-rat brain NOS antibody, in
a single-cell freshwater eukaryote, Paramecium primaurelia. In this work we have looked for the basal NO
production in living cells of P. primaurelia using the specific fluorescent probe 4,5-diaminofluorescein
diacetate (DAF-2 DA) and measuring the intracellular NO levels with image analysis. The NO production
was sensitive to compounds modulating NOS activity such as: S-methyl-tiocitrulline, an NOS activity
inhibitor, L-NAME, an analogue of arginine that inhibits NO production, arginine, an NOS substrate, or
sodium nitroprusside, an NO donor. The NO production in P. primaurelia was also shown to be sensitive
to mM concentrations of heavy metals (HgCl2 and CdCl2), or mM concentrations of pesticides (diazinon
and AFD 25), thus representing a potential biomarker for environmental biomonitoring. The possible
involvement of cellular Ca2+ concentration, assayed by the fluorescent probe chlortetracycline
hydrochloride, in NO production was examined after xenobiotic exposure.
Additional details
Identifiers
- URL
- http://hdl.handle.net/11567/217538
- URN
- urn:oai:iris.unige.it:11567/217538