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Hussein Rohde posted an update 4 hours, 2 minutes ago
Multigenerational effects of silver nanoparticles (Ag-NPs) on reproduction of the soil nematode Caenorhabditis elegans have been observed previously. However, mechanisms of this reproductive sensitivity are unknown. Here we examine whether epigenetic changes occur as a result of multigenerational exposure to Ag-NPs and whether such modifications can be inherited by unexposed generations. Changes at histone methylation markers, histone 3 lysine 4 dimethylation (H3K4me2) and histone 3 lysine 9 trimethylation (H3K9me3), known to affect reproduction, as well as changes in the expression of the genes encoding demethylases and methyltransferases associated with the selected markers, were investigated. We exposed C. elegans at EC30 to AgNO3, pristine Ag-NPs, and its environmentally transformed product, sulfidized Ag-NPs (sAg-NPs). Histone methylation levels at H3K4me2 increase in response to pristine Ag-NP exposure and did not recover after rescue from the exposure, suggesting transgenerational inheritance. Compared to pristine Ag-NPs, exposure to transformed sAg-NPs significantly decreased H3K4me2 and H3K9me3 levels. These changes in the histone methylation were also supported by expression of spr-5 and jmjd-2 (H3K4me2 and H3K9me3 demethylases, respectively) and set-30 (H3K4me2 methyltransferase). Our study demonstrates that multigenerational exposure to Ag-NPs induces epigenetic changes that are inherited by unexposed offspring. However, environmental transformations of Ag-NPs may also reduce toxicity via epigenetic mechanisms, such as changes at histone methylation. Mankind is taking advantage of numerous services by small shallow lakes such as drinking water supply, irrigation, and recreational function; however, many of these lakes suffer from eutrophication. Given the key role of phosphorus (P) in eutrophication process, one of the effective restoration methods especially for small shallow lakes is removal of sediments enriched with nutrients. In our study, we used interannual, seasonal, and spatial data to examine the changes in sediment P mobility after removal of sediments in 2016 from a 1-ha highly eutrophic lake. We measured the sediment redox potential, analyzed soluble reactive P (SRP) in the pore water and P fractional composition of the surface sediments, and calculated the diffusive flux of P in three locations in two continuous years (2017 and 2018) after the excavation. Similar measurements were done before sediment removal at central site of the lake in 2015. Removing nutrient-rich sediment also removed 6400 kg of P, and thus the potential for release of P from sediments decreased on a long-term scale. However, a large pool of releasable P was rebuilt soon after the sediment removal due to high external P loading, resulting in extensive anoxia of sediment surface and associated internal P loading as high as 1450 mg m-2 summer-1. Moreover, the Fe-P and labile P fractions were the most important sources of P release, as evidenced by their considerable seasonal and interannual changes after the sediment removal. The sediment total Fe negatively correlated with diffusive flux of P, pore water SRP, and near-bottom water total P and SRP concentrations which indicated a strong linkage between sediment P dynamics and Fe after the restoration. Sediment removal could be a beneficial restoration approach, but the effects on lake water quality remain only short-term unless there is an adequate control on external loading to the lake. Our study underpins the mechanism of organo-mineral interaction between black carbon (BC, biochar) and associated minerals in the historical BC-rich Amazonian Dark Earth (ADE) by using synchrotron-based microscopic (TXM), microspectroscopic (μFTIR) and spectroscopic (XAS and μ-diffraction) approaches. The BC-rich ADE contained over 100% more poorly crystalline minerals than the adjacent tropical soil. Linear combination fitting of k-spacing in the X-ray Absorption Spectra (XAS) revealed that ferrihydrite contributed to 81.1% of the Fe-minerals in BC. A small but distinct peak was observed at 5.7 Å-1 in the extended X-ray absorption fine structure k oscillation of BC, revealing the presence of FeC (including Fe-O-C) covalent bonds. No FeC path was yielded by the XAS fitting when an obvious peak downshift of the first (FeFe1) shell was observed, suggesting that the availability of inner-sphere FeC complexation was limited to the BC surface and interphase region. The main minerals for organo-mineral complexation in the soil. A new diffusive gradients in thin films technique (ZrO-AT DGT) with zirconium oxide, A-62 MP and T-42H resins containing in a single binding gel was developed for simultaneous measurement of nitrate (NO3-N), ammonium (NH4-N) and phosphate (PO4-P). The DGT uptake was found to be independent of pH variation from 3.2-8.7. Ionic strengths below 5, 10 and 750 mmol·L-1 NaCl did not affect DGT uptake of NH4-N, NO3-N and PO4-P, respectively. This new DGT was deployed in natural freshwater environments, with in situ measurements of the three nutrients found to be accurate. FRAX486 supplier It ensured that rinsing the exposed surface of the DGT device at 3-day intervals can prevent biofouling. Additionally, a hybrid sensor comprising the novel DGT binding layer overlying an O2 planar optrode was tested in sediments to evaluate the dynamics of O2 and the three nutrients. Results showed that PO4-P and NO3-N fluxes decreased while fluxes of NH4-N increased under aerobic conditions. Nearly simultaneous variation in O2 and NO3-N was observed at the sediment-water interface (SWI) and transformation of NO3-N and PO4-P was found to be sensitively influenced by O2 dynamics. Pork is the main meat produced and consumed in the Philippines. The majority of pigs are raised by smallholders who experience a range of constraints to their pig production. This study presents the findings of the first part of an overarching project that used an Ecohealth approach and aimed to improve the production and competitiveness of the smallholder pig system in an area of the Philippines. A participatory approach was embraced, combining conventional and participatory epidemiology methods followed by a stakeholder discussion. The first aim was to identify management and health-related constraints to pig production among smallholder famers in San Simon, Pampanga, Philippines. The second aim was for the project team and stakeholders to jointly prioritise activities for the immediate future to address these constraints. Key management and health-related constraints identified included inadequate water supply to pigs, particularly lactating and gestating sows, and a range of feeding-related issues. Diarrhoea was recognised as the disease syndrome of highest priority and limited record keeping meant that farmers were unable to assess the productivity and profitability of their pig farming enterprises.