Drought Alleviates the Negative Effects of Microplastics on Soil Micro-Food Web Complexity and Stability

Soil ecosystems are under considerable pressure due to anthropogenic factors, including microplastics (MPs) pollution and drought. However, little is known about the interactive effects of MPs and drought on soil organisms, especially soil micro-food web. We conducted a microcosm experiment with MPs pollution (including two types and two sizes of MPs) and drought to investigate their interaction effects on soil microbial, protist, and nematode communities in soil micro-food web. We found that MPs significantly decreased the complexity and stability of soil micro-food web, with greater negative effects of biodegradable and smaller-sized MPs than conventional and larger-sized MPs. Drought had negative effects on soil micro-food web in the non-MPs pollution soils while increasing the complexity and stability of soil micro-food web in the MPs pollution soils. Drought increased the proportion of negative correlations between bacteria and fungi in the biodegradable MPs soils while decreasing the proportion of negative correlations between protists and nematodes in the smaller-sized MPs soils. Our study reveals that drought may alleviate the negative effects of MPs on soil micro-food web by reducing competition among lower trophic levels in the biodegradable MPs pollution soils while reducing competition among higher trophic levels in the smaller-sized MPs pollution soils

Eeffect of desflurane on SMAC release and capase-3 cleavage.

<p>Western blot analysis showing cytosolic SAMC (A) and total caspase-3 (B). Equal loading was confirmed by western blot with an anti-β-actin antibody. The cytosolic SMAC and total caspsase-3 concentrations were calculated by averaging the results obtained from five independent experiments. Data are presented as mean±SD. *<i>P</i><0.05 versus CON group, ^#<i>P</i><0.05 versus DES+A/R group.</p

Effect of desflurane on expression of Bcl-2, c-IAP1 and SOD activity.

<p>Western blot analysis showing concentration of Bcl-2 (A), c-IAP1 (B). Equal loading was confirmed by western blot with an anti-β-actin or anti-tubulin antibody. The Bcl-2 and c-IAP1protein concentrations were calculated by averaging the results obtained from five independent experiments. The SOD activity was measured by WST-1 assay (C). Data are presented as mean±SD. *<i>P</i><0.05 versus CON group, ^#<i>P</i><0.05 versus DES+A/R group.</p

Desflurane preconditioning induced oscillation of NF-κB between nucleus and cytoplasm.

<p>Broken arrow refers to unconfirmed part of current study.</p

Experiment protocols.

<p>HUVECs submitted to the anoxia and reoxygenation (A/R) and pretreated with and without 1.0 minimum alveolar concentration (MAC) desflurane or 5 µM BAY11-7082 (BAY). For cell viability, apoptosis, SOD activity assays, the cell samples were collected at the end of experiments. For western blot analysis, cell samples were collected at the end of reoxygenation (samples were collected at 45 min after baseline in CON group and 15 min after desflurane exposure in DES group).</p

HUVECs immunofluorescence stained with anti-factor VIII related antibody.

<p>Column 1 is the image of factor VIII (green) in cytoplasm, column 2 is the image of nuclei (blue) and column 3 is the merged image. Magnification ×40.</p

Effect of desflurane on NF-κB p65 nuclear translocation.

<p>Immunofluorescence assay showing NF-κB p65 subunit (green) translocated to nuclei (blue) after exposure to desflurane or A/R. Arrowheads signify some positive nuclei. Magnification ×200.</p

Effect of desflurane preconditioning on HUVECs submitted to A/R.

<p>Cells were submitted to A/R with or without pretreated with desflurane for 30 min or 5 µM BAY11-7082 (BAY). The viability was measured by MTT assay (A). The apoptosis rate was measured by FACSan flow cytometry (B). Data are presented as mean±SD. n = 6/group. *<i>P</i><0.05 versus CON group,^#<i>P</i><0.05 versus DES+A/R group.</p

Kaplan–Meier survival curves according to serum sodium concentration.

<p>The serum sodium level affects mainly the 3-year mortality rate of patients. The 3-year cumulative survival rates for patients with moderate/severe and mild hyponatremia were 47.8%±8.5% and 59.8%±5.0%, respectively, and 78.2%±3.8% for normonatremic patients (Log-Rank, <i>P</i><0.001).</p

Mean serum sodium concentration in patients according to CD4 count and WHO stage.

<p>Serum sodium concentration decreases with a reduction in CD4 count and an increases with WHO stage (F = 7.004, <i>P</i><0.001).</p