IBAM   22618
INSTITUTO DE BIOLOGIA AGRICOLA DE MENDOZA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Mercury biotransformation monitoring in vitis vinifera cv malbec by liquid chromatography coupled to atomic spectrometries
Autor/es:
ADRIÁN SPISSO ; FERNANDA SILVA; FEDERICO J.V. GOMEZ; PABLO PACHECO
Reunión:
Simposio; Secon Latin American Metabolic Profiling Symposium; 2016
Resumen:
The present study evaluates the changes in Hg distribution for a two-year period in vines (Vitis vinifera cv Malbec) by coupling different liquid chromatography [LC] modes to atomic spectrometries; inductively coupled plasma mass spectrometry [ICP MS] and atomic fluorescence spectrometry [AFS]. To this end, vines were administered with 100 mg L-1 Hg solution for 3 days, simulating acute poisoning by watering with Hg contaminated waters. Sampling of roots, stems and leaves was performed one week after administration and at regular periods for two years, depending on availability. Total Hg was evaluated by microwave assisted digestion [MAD] of plant organs followed by ICP MS determination. Hg distribution according to molecular weight was evaluated by coupling size exclusion chromatography [SEC] to ICP MS. Hg metabolites like Hg-phytochelatins [Hg-PCs] complexes; or methyl mercury, phenyl mercury, dimethyl mercury and ethyl mercury were evaluated by reversed phase chromatography [RPC] coupled to AFS, by two dimension chromatography. Results showed that vines uptake Hg translocating it from roots through stems to leaves. Roots accumulated the highest Hg concentration. Hg in stems and leaves was accumulated mostly as organic Hg, bind to different moieties [1]. SEC showed that Hg is distributed mainly in high molecular weight [HMW] fractions of 669 kDa in vine plants. In stems and leaves, Hg−S associations were found in 669 and 66 kDa fractions. Hg−S association at medium molecular weight [MMW] fraction, 66 kDa, which suggests a possible protein or peptide binding affecting vines normal physiology. From these outcomes, Hg-PCs complexes were evaluated by RPC-AFS in this fraction, in a second dimension chromatography. Chromatograms showed Hg-PC2, Hg-PC3 and Hg-PC4 presence only in roots [2]. Since Hg contamination through organomercurials is more harmful than Hg2+ itself, methyl mercury, dimethyl mercury, and phenyl mercury, more toxic Hg species were evaluated by RPC-AFS with negative results.The initial Hg concentration of 86.43 ± 15.98 μg g−1 absorbed by vines was reduced to 32% after six months, and to 11% after one year post administration. After two years Hg was only detectable in roots, at concentrations close to control plants (0.06 ± 0.01 μg g−1). Regard Hg distribution according to molecular weight, after one year the only detectable fraction detected was the HMW fractions of 669 kDa. No MMW or low molecular weight [LMW] fractions associated to Hg were determined one year after administration; however sulfur fractions of MMW and LMW determined at initial stages were continuously detected. These observations, along with PCs detection, show elevated Hg metabolism in MMW and LMW fractions. Hg associations to HMW fractions probed to be more conserved since they were continuously detected after one year post Hg administration.