scholarly journals Mercury Bioavailability in Fluvial Sediments Estimated Using Chironomus riparius and Diffusive Gradients in Thin-Films (DGT)

Environments ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 7
Author(s):  
Laura Marziali ◽  
Lucia Valsecchi
Keyword(s):  
Quality Standard ◽  
Chironomus Riparius ◽  
Passive Samplers ◽  
Fluvial Sediments ◽  
Top Predators ◽  
Aquatic Food ◽  
Accumulation Kinetics ◽  
Whole Life Cycle ◽  
Diffusive Gradients ◽  
Kinetics Of

Mercury bioavailability was assessed by exposing the dipteran Chironomus riparius for the whole life cycle to legacy-contaminated fluvial sediments (0.038–0.285 mg Hg kg−1 d.w.) and analyzing tissue concentrations in larvae at different exposure times (7, 11, and 16 days) and in adults. In the same experiment, diffusive gradients in thin-film passive samplers (DGTs), both piston- and probe-shaped, were co-deployed in the same sediments and retrieved at the same times as the organisms. To compare the two approaches, results showed a good agreement between accumulation kinetics of C. riparius and DGTs, both approximating an apparent steady-state. A strong correlation was found between values in tissues and in both types of DGTs (r between 0.74 and 0.99). Concentrations in mature larvae (19–140 µg kg−1 w.w.), which may represent a basal level of the aquatic food web, exceeded the European Environmental Quality Standard for biota (20 µg kg−1 w.w.), which aims at protecting the top predators from secondary poisoning. Body burdens in larvae and in adults were similar, showing negligible decontamination during metamorphosis and proving an efficient mercury transfer from sediments to terrestrial food webs.

scholarly journals Tbx21 and Foxp3 Are Epigenetically Stabilized in T-Bet+ Tregs That Transiently Accumulate in Influenza A Virus-Infected Lungs

2021 ◽  
Vol 22 (14) ◽  
pp. 7522
Author(s):  
Yassin Elfaki ◽  
Juhao Yang ◽  
Julia Boehme ◽  
Kristin Schultz ◽  
Dunja Bruder ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
T Cell Subsets ◽  
T Helper 1 ◽  
T Box ◽  
Cell Responses ◽  
Accumulation Kinetics ◽  
Kinetics Of

During influenza A virus (IAV) infections, CD4+ T cell responses within infected lungs mainly involve T helper 1 (Th1) and regulatory T cells (Tregs). Th1-mediated responses favor the co-expression of T-box transcription factor 21 (T-bet) in Foxp3+ Tregs, enabling the efficient Treg control of Th1 responses in infected tissues. So far, the exact accumulation kinetics of T cell subsets in the lungs and lung-draining lymph nodes (dLN) of IAV-infected mice is incompletely understood, and the epigenetic signature of Tregs accumulating in infected lungs has not been investigated. Here, we report that the total T cell and the two-step Treg accumulation in IAV-infected lungs is transient, whereas the change in the ratio of CD4+ to CD8+ T cells is more durable. Within lungs, the frequency of Tregs co-expressing T-bet is steadily, yet transiently, increasing with a peak at Day 7 post-infection. Interestingly, T-bet+ Tregs accumulating in IAV-infected lungs displayed a strongly demethylated Tbx21 locus, similarly as in T-bet+ conventional T cells, and a fully demethylated Treg-specific demethylated region (TSDR) within the Foxp3 locus. In summary, our data suggest that T-bet+ but not T-bet− Tregs are epigenetically stabilized during IAV-induced infection in the lung.

Kinetics of mercury accumulation by freshwater biofilms

2017 ◽  
Vol 14 (7) ◽  
pp. 458 ◽  
Author(s):  
Perrine Dranguet ◽  
Vera I. Slaveykova ◽  
Séverine Le Faucheur
Keyword(s):  
Food Webs ◽  
Food Chain ◽  
Microbial Composition ◽  
Biofilm Thickness ◽  
Aquatic Microorganisms ◽  
Uptake Rate Constant ◽  
The Difference ◽  
Accumulation Kinetics ◽  
Kinetics Of ◽  
Hg Accumulation

Environmental contextMercury (Hg) is a major environmental contaminant due to its toxicity, accumulation and biomagnification along the food chain. We demonstrate that Hg accumulation by biofilms, one possible entry point for Hg into food webs, is rapid and depends on biofilm structure and composition. These findings have important implications for the understanding of Hg bioavailability and effects towards aquatic microorganisms. AbstractMercury contamination is of high concern due to its bioaccumulation, toxicity and biomagnification along the food chain. Biofilms can accumulate Hg and contribute to its incorporation in freshwater food webs. Nevertheless, the accumulation kinetics of Hg by biofilms is not well described and understood. The aim of the present study was thus to gain mechanistic understanding of Hg accumulation by biofilms. Kinetics of Hg uptake by biofilms of different ages (e.g. different compositions) was characterised by determining Hg contents in biofilms with and without a cysteine-washing step. Hg accumulation was rapid in both biofilms, with the uptake rate constant of the younger biofilm 10 times higher than that of the older biofilm. Moreover, accumulated Hg reached a plateau at 24h exposure in the younger biofilm, whereas it increased linearly in the older biofilm. The observed difference in Hg uptake by the studied biofilms is likely a result of the difference in biofilm thickness (and thus Hg diffusion inside the biofilm matrix) and microbial composition. These findings have important implications for the understanding of Hg bioavailability and effects towards aquatic microorganisms.

Transfer Kinetics of Polar Organic Compounds over Polyethersulfone Membranes in the Passive Samplers Pocis and Chemcatcher

2012 ◽  
Vol 46 (12) ◽  
pp. 6759-6766 ◽  
Author(s):  
Etiënne L. M. Vermeirssen ◽  
Conrad Dietschweiler ◽  
Beate I. Escher ◽  
Jürgen van der Voet ◽  
Juliane Hollender
Keyword(s):  
Organic Compounds ◽  
Passive Samplers ◽  
Polar Organic Compounds ◽  
Kinetics Of

Biphasic accumulation kinetics of [99mTc]-hexakis-2-methoxyisobutyl isonitrile in tumour cells and its modulation by lipophilic P-glycoprotein ligands

2005 ◽  
Vol 25 (2-3) ◽  
pp. 201-209 ◽  
Author(s):  
Teréz Márián ◽  
László Balkay ◽  
Gábor Szabó ◽  
Zoárd T. Krasznai ◽  
Zoltán Hernádi ◽  
...  
Keyword(s):  
Tumour Cells ◽  
P Glycoprotein ◽  
Accumulation Kinetics ◽  
Kinetics Of

scholarly journals Tissue Accumulation Kinetics of Ciclesonide‐active Metabolite and Budesonide in Mice

2013 ◽  
Vol 112 (6) ◽  
pp. 401-411 ◽  
Author(s):  
Ulla Mårs ◽  
Roland d'Argy ◽  
Karin Hallbeck ◽  
Anna Miller‐Larsson ◽  
Staffan Edsbäcker
Keyword(s):  
Active Metabolite ◽  
Tissue Accumulation ◽  
Accumulation Kinetics ◽  
Kinetics Of

Desorption kinetics of tetracyclines in soils assessed by diffusive gradients in thin films

2020 ◽  
Vol 256 ◽  
pp. 113394
Author(s):  
Suyu Ren ◽  
Yi Wang ◽  
Ying Cui ◽  
Yan Wang ◽  
Xiaochun Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Desorption Kinetics ◽  
Diffusive Gradients ◽  
Kinetics Of

Accumulation of VO Defects in N-Si at High-Temperature Pulse Electron Irradiation: Generation and Annealing Kinetics, Dependence on Irradiation Intensity

2011 ◽  
Vol 178-179 ◽  
pp. 404-409
Author(s):  
Mykola Kras'ko ◽  
Anatolii Kraitchinskii ◽  
Andrii Kolosiuk ◽  
Volodymyr Neimash ◽  
Vasyl Voitovych ◽  
...  
Keyword(s):  
Electron Irradiation ◽  
Electron Pulse ◽  
Maximal Concentration ◽  
Pulse Irradiation ◽  
Generation Efficiency ◽  
Simultaneous Generation ◽  
Irradiation Intensity ◽  
Order Of Magnitude ◽  
Accumulation Kinetics ◽  
Kinetics Of

Accumulation kinetics of vacancy-oxygen (VO) complexes in Czochralski (Cz) n-Si at 360 °C and 1 MeV electron pulse irradiation has been investigated. It is shown that during the irradiation and simultaneous generation and annealing of VO centers, the accumulation kinetics has non-linear dependence with saturation. It is found that there is a maximal concentration of VO centers, which depends on the radiation intensity (J) and temperature as well. It is also established the annealing of VO centers can substantially be stimulated by the intensity of electron irradiation. An increase of J from 1.25×1015 to 1.25×1016 electrons/(сm2s) does not influence the generation efficiency of VO, though it accelerates their annealing by more than one order of magnitude.

Sign in / Sign up

Export Citation Format

Share Document