Search results for "METHYLMERCURY"

Environmental and biological factors are joint drivers of mercury biomagnification in subarctic lake food webs along a climate and productivity gradi…

2021

Subarctic lakes are getting warmer and more productive due to the joint effects of climate change and intensive land-use practices (e.g. forest clear-cutting and peatland ditching), processes that potentially increase leaching of peat- and soil-stored mercury into lake ecosystems. We sampled biotic communities from primary producers (algae) to top consumers (piscivorous fish), in 19 subarctic lakes situated on a latitudinal (69.0-66.5 degrees N), climatic (+3.2 degrees C temperature and +30% precipitation from north to south) and catchment land-use (pristine to intensive forestry areas) gradient. We first tested how the joint effects of climate and productivity influence mercury biomagnific…

2017

Abstract Background Results on the association between prenatal exposure to methylmercury (MeHg) and child neuropsychological development are heterogeneous. Underlying genetic differences across study populations could contribute to this varied response to MeHg. Studies in Drosophila have identified the cytochrome p 450 3A (CYP3A) family as candidate MeHg susceptibility genes. Objectives We evaluated whether genetic variation in CYP3A genes influences the association between prenatal exposure to MeHg and child neuropsychological development. Methods The study population included 2639 children from three birth cohort studies: two subcohorts in Seychelles (SCDS) (n = 1160, 20 and 30 months of…

Methylmercury-induced developmental toxicity is associated with oxidative stress and cofilin phosphorylation. Cellular and human studies

2017

Environmental exposure to methylmercury (MeHg) during development is of concern because it is easily incorporated in children’s body both pre- and post-natal, it acts at several levels of neural pathways (mitochondria, cytoskeleton, neurotransmission) and it causes behavioral impairment in child. We evaluated the effects of prolonged exposure to 10–600 nM MeHg on primary cultures of mouse cortical (CCN) and of cerebellar granule cells (CGC) during their differentiation period. In addition, it was studied if prenatal MeHg exposure correlated with altered antioxidant defenses and cofilin phosphorylation in human placentas (n = 12) from the INMA cohort (Spain). Exposure to MeHg for 9 days in v…

The ascidian Styela plicata hemocytes as a potential biomarker of marine pollution: In vitro effects of seawater and organic mercury.

2017

Toxic metals, such as mercury, contribute substantially to anthropogenic pollution in many estuarine environments. Animals living in those environments, particularly invertebrate filter feeders like tunicates, can be used as bioindicators. In an attempt to identify cellular markers for revealing pollution, this study examined in vitro the effects of different concentrations of methyl mercury on Styela plicata hemocytes. The harvested hemocytes from S. plicata that were exposed to the metal had a significant mortality, cellular count and morphometric alterations. These findings provided evidence of MeHg immunotoxic effects on S. plicata, resulting in hemocyte death and morphological changes …

Dietary exposure to trace elements and health risk assessment in the Region of Valencia (Spain). A Total Diet Study

2016

ABSTRACTDietary exposure of the Valencian region population to lead, cadmium, inorganic arsenic (iAs), chromium, copper, tin and methylmercury (meHg) was assessed in a total diet study carried out in the region of Valencia in 2010–11. A total of 8100 food samples were collected and analysed. Occurrence data were combined with consumption data to estimate dietary exposure in adults (> 15 years of age) and young children (6–15 years of age). The estimated intake was calculated by a probabilistic approach. Average intake levels (optimistic scenario) for lead, iAs, chromium and tin were 0.21, 0.08, 1.79 and 1.87 µg kg−1 bw day−1 respectively; for Cd and meHg average intake levels were 0.77 and …

In vitro effects of methylmercury on ascidian (Styela plicata) immunocyte responses

2007

This study shows that high methylmercury concentrations are cytotoxic for Styela plicata hemocytes, whereas sublethal concentrations affect immunocyte responses. Moreover, hemocytes exposed to the xenobiotic present a significantly enhanced phenoloxidase activity as revealed in the hemocyte lysate supernatant compared with the control. Although the cytotoxic activity of S. plicata hemocytes toward rabbit erythrocytes is a PO-dependent cell-target reaction due to quinone products, it was significantly decreased by suitable methylmercury concentrations in the medium. The same xenobiotic concentrations decreased the hemocyte phagocytic activity toward yeast. In both the responses cell-target c…

Effetti tossici del metilmercurio sulle risposte immunitarie dell'ascidia Styela plicata

2008

Prevalence of heterotrophic methylmercury detoxifying bacteria across oceanic regions

2022

10 pages, 4 figures, 1 table, supporting information https://doi.org/10.1021/acs.est.1c05635

Sequestration of organomettalic compounds by synthetic and naturally occuring polycarboxylate ligands. Binding of monomethylmercury(II) by polyacryli…

2007

The sequestering capacity of synthetic and naturally occurring polycarboxylate ligands towards mono- methylmercury(II) was evaluated by stability quantitative data on the interaction of CH3Hgþ with different molecular weight synthetic polyacrylates (2 and 20 kDa average M.wt) and alginate (70– 100 kDa) extracted from brown algae Macrocystis pyrifera. The influence of ionic medium was evaluated by measurements on the CH3Hgþ-polyacrylate systems in NaNO3 medium at different ionic strengths (0.10, 0.25, 0.50 and 0.75mol Lÿ1), and a Debye–Hu¨ ckel type equation was used for the dependence of complex formation constants on ionic strength. Measurements on the CH3Hgþ - alginate system were carried…

A multinjection strategy for mercury speciation.

2005

Abstract A multiinjection strategy has been developed to increase the sampling throughput of the high-performance liquid chromatography determination of inorganic-mercury, methylmercury, ethylmercury and phenylmercury. The method involves the injection of samples each 3.5 min, in spite of the fact that phenylmercury retention time corresponds to 9.04 min. In the selected conditions, the sampling frequency was 11 h −1 in front of that of 6 h −1 , obtained by conventional injection of each sample after the complete elution of Hg species. Additionally, the analytical reagents consumption was reduced drastically in almost 50%. The main characteristics of the chromatographic separation were main…