Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Changes in the non-protein thiol pool and production of Dissolved Gaseous Mercury in the marine diatom Thalassiosira weissflogii under mercury exposure. |
| Abstract | Two detoxification mechanisms working in the marine diatom Thalassiosira weissfloggii to cope with mercury toxicity were investigated. Initially, the effect of mercury on the intracellular pool of non-protein thiols was studied in exponentially growing cultures exposed to sub-toxic HgCl2 concentrations. T. weissfloggii cells responded by synthesizing metal-binding peptides, named phytochelatins (PCs), besides increasing the intracellular pool of glutathione and ?-glutamylcysteine (?-EC). Intracellular Hg and PC concentrations increased with the Hg concentration in the culture medium, exhibiting a distinct dose-response relationship. However, considerations of the PCs-SH:Hg molar ratio suggest that also glutathione could be involved in the intracellular mercury sequestration. The time course of the non-protein thiol pool and Hg intracellular concentration shows that PCs, glutathione and ?-EC represent a rapid cellular response to mercury, although their role in Hg detoxification seems to lose importance at longer incubation times. The occurrence of a process of reduction of Hg(II) to Hg° and subsequent production of dissolved gaseous mercury (DGM) was also investigated at lower Hg concentrations, at which the PC synthesis doesn't seem to be involved. The significant (P<0.01) correlation between the cellular density in solution and the production of DGM suggests that this diatom is capable of directly producing DGM, both in light and dark conditions. This finding has been confirmed by the absence of DGM production in the culture media containing formaldehyde-killed cells. Finally, the relationship between these two different pathways of Hg detoxification is discussed. |
| Source | Science of the total environment 408, pp. 286–293 |
| Keywords | Dissolved gaseous mercuryNon-protein thiolsphytochelatinsPhytoplanktonThalassiosira weissflogii |
| Journal | Science of the total environment |
| Editor | Elsevier, Lausanne ;, Paesi Bassi |
| Year | 2009 |
| Type | Articolo in rivista |
| DOI | 10.1016/j.scitotenv.2009.09.047 |
| Authors | Morelli E.; Ferrara R.; Bellini B.; Dini F.; Di Giuseppe G.; Fantozzi L. |
| Text | 9798 2009 10.1016/j.scitotenv.2009.09.047 ISI Web of Science WOS 000272564500014 Dissolved gaseous mercury Non protein thiols phytochelatins Phytoplankton Thalassiosira weissflogii Changes in the non protein thiol pool and production of Dissolved Gaseous Mercury in the marine diatom Thalassiosira weissflogii under mercury exposure. Morelli E.; Ferrara R.; Bellini B.; Dini F.; Di Giuseppe G.; Fantozzi L. Elisabetta Morelli, Romano Ferrara, Barbara Bellini, Laura Fantozzi Istituto di Biofisica CNR , Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa, Italy; Fernando Dini, Graziano Di Giuseppe Dipartimento di Biologia, Universita di Pisa, Via A. Volta 4, 56126 Pisa, Italy Two detoxification mechanisms working in the marine diatom Thalassiosira weissfloggii to cope with mercury toxicity were investigated. Initially, the effect of mercury on the intracellular pool of non protein thiols was studied in exponentially growing cultures exposed to sub toxic HgCl2 concentrations. T. weissfloggii cells responded by synthesizing metal binding peptides, named phytochelatins PCs , besides increasing the intracellular pool of glutathione and glutamylcysteine EC . Intracellular Hg and PC concentrations increased with the Hg concentration in the culture medium, exhibiting a distinct dose response relationship. However, considerations of the PCs SH Hg molar ratio suggest that also glutathione could be involved in the intracellular mercury sequestration. The time course of the non protein thiol pool and Hg intracellular concentration shows that PCs, glutathione and EC represent a rapid cellular response to mercury, although their role in Hg detoxification seems to lose importance at longer incubation times. The occurrence of a process of reduction of Hg II to Hg° and subsequent production of dissolved gaseous mercury DGM was also investigated at lower Hg concentrations, at which the PC synthesis doesn t seem to be involved. The significant P<0.01 correlation between the cellular density in solution and the production of DGM suggests that this diatom is capable of directly producing DGM, both in light and dark conditions. This finding has been confirmed by the absence of DGM production in the culture media containing formaldehyde killed cells. Finally, the relationship between these two different pathways of Hg detoxification is discussed. 408 Articolo pubblicato STOTEN_2009.pdf Articolo in rivista Elsevier 0048 9697 Science of the total environment Science of the total environment Sci. total environ. FERRARA ROMANO laura.fantozzi FANTOZZI LAURA BELLINI BARBARA elisabetta.morelli MORELLI ELISABETTA TA.P05.015.002 Meccanismi di risposta cellulare a contaminanti ambientali |