ORCID Profile
0000-0002-1891-7365
Current Organisation
University of Aveiro
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Publisher: Wiley
Date: 12-2008
DOI: 10.1897/08-154.1
Abstract: The present study examined how subcellular partitioning of Cd in plants with different strategies to store and detoxify Cd may affect trophic transfer of Cd to the isopod Porcellio dilatatus. The plant species used were Lactuca sativa, a horticultural metal accumulator species Thlaspi caerulescens, a herbaceous hyperaccumulator species and the nonaccumulator, T. arvense. Taking into account that differences in subcellular distribution of Cd in plants might have an important role in the bioavailability of Cd to a consumer, a differential centrifugation technique was adopted to separate plant leaf tissues into four different fractions: cell debris, organelles, heat-denatured proteins, and heat-stable proteins (metallothionein-like proteins). Plants were grown in replicate hydroponic systems and were exposed for 7 d to 100 microM Cd spiked with 109Cd. After a 14-d feeding trial, net assimilation of Cd in isopods following consumption of T. caerulescens and T. arvense leaves reached 16.0 +/- 2.33 and 21.9 +/- 1.94 microg/g animal, respectively. Cadmium assimilation efficiencies were significantly lower in isopods fed T. caerulescens (10.0 +/- 0.92%) than in those fed T. arvense (15.0 +/- 1.03%). In further experiments, Cd assimilation efficiencies were determined among isopods provided with purified subcellular fractions of the three plants. On the basis of our results, Cd bound to heat-stable proteins was the least bioavailable to isopods (14.4-19.6%), while Cd bound to heat-denatured proteins was the most trophically available to isopods (34.4-52.8%). Assimilation efficiencies were comparable in isopods fed purified subcellular fractions from different plants, further indicating the importance of subcellular Cd distribution in the assimilation. These results point to the ecological relevance of the subcellular Cd distribution in plants, which directly influence the trophic transfer of Cd to the animal consumer.
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.ECOENV.2010.06.020
Abstract: Cadmium (Cd) is a widespread environmental contaminant, strongly mutagenic and known to cause DNA damage in plants. In this work, flow cytometry (FCM) was applied to determine if in vivo exposure to Cd would induce genotoxic effects at the genome level. The hyper-accumulator Thlaspi caerulescens (J. & C. Presl), the related non-accumulator Thlaspi arvense L. and the accumulator crop species Lactuca sativa L. were germinated in distilled water and grown in modified Hoagland's medium with increasing concentrations of Cd(NO3)2 (0, 1, 10 and 100 microM). After 28 days of exposure, shoot and root growth was recorded and the tissues were harvested for Cd and FCM analysis. In general, roots from treated plants contained higher content of Cd than leaves and growth inhibition was observed in the treated plants. Nuclear DNA content was estimated and the G0/G1 full peak coefficient of variation (FPCV), as an indicator of clastogenic damage, was recorded. In T. arvense and T. caerulescens no significant differences were detected between control and exposed plants. Leaves of L. sativa exposed to 10 microM Cd presented a statistically significant increase in FPCV values in comparison with the control group. Furthermore, roots exposed to 100 microM Cd presented a reduction in nuclear DNA content and an increase in FPCV when compared to the control. FCM data indicates that no major DNA damage was induced on both Cd-exposed Thlaspi species and L. sativa leaves. On the contrary, results obtained with L. sativa roots suggests clastogenic damage in these organs exposed to 100 microM of Cd.
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.ECOENV.2008.08.002
Abstract: Laboratory and field studies have provided encouraging insights into the capacity of plants to act as biomonitors of environmental quality through the use of biomarkers. However, a better understanding of the overall process of Cd-induced senescence, describing the cascade of Cd effects in plants is needed for a selection of relevant biomarkers of Cd stress. In order to approach this, 5-week old Lactuca sativa L. were exposed for 14 days to 100muM Cd(NO(3))(2) and harvested at days 0, 1, 3, 7 and 14. The parameters measured included classical endpoints (shoot and root growth) and biochemical endpoints related to photosynthesis, nutrients content, and oxidative stress. Cadmium-exposed plants displayed nutrient imbalances in leaves and roots. Photosynthetic efficiency was significantly decreased and lipid peroxidation was enhanced. Antioxidant enzymes were significantly altered during exposure-catalase was inhibited by the end of exposure and peroxidase was induced at day 1 in young leaves. These alterations culminated in a decrease in shoot growth after 14-days exposure to Cd. Biochemical alterations could be used in integrative approaches with classical endpoints in ecotoxicological tests for Cd and after further testing in real scenarios conditions, they could form the basis of a plant biomarkers battery for monitoring and predicting early effects of exposure to Cd.
Publisher: Elsevier BV
Date: 07-2007
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.MRGENTOX.2008.10.012
Abstract: Cadmium (Cd) is a cytotoxic, mutagenic and carcinogenic metal. Mutagenesis is indicative of genetic instability and can be assayed by use of microsatellite markers (simple sequence repeats, SSRs). These are tandem-repeated tracts of DNA composed of units that are 1-6 base pairs (bp) long, spread throughout the genome and highly polymorphic. SSRs can be used in the detection of genomic DNA damage and/or mutational events (e.g. deletions, insertions, point mutations). In order to study chronic exposure to cadmium, Lactuca sativa L. seeds were germinated in distilled water and grown on modified Hoagland's medium, both supplemented with 0, 10 and 100microM Cd(NO(3))(2). After 28 days of exposure, the plants were harvested to assess shoot and root length and accumulation of cadmium. DNA was extracted from young and expanded leaves and roots in order to analyse microsatellite instability (MSI). Mutagenic effects of cadmium were evaluated on nine microsatellite loci. No MSI was found in leaves, but a 2-bp deletion in one lettuce root SSR was detected among the SSRs that were analysed. Thus, SSR analyses may provide a complementary tool in the assessment of different genotoxic effects of compounds on plants.
No related grants have been discovered for Marta Monteiro.