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Dynamics of soil N2O emissions and functional gene abundance in response to biochar application in the presence of earthworms Full text
2021
Wu, Yupeng | Liu, Jiao | Shaaban, Muhammad | Hu, Ronggui
Nitrous oxide (N₂O) is a devastating greenhouse gas and acts as an ozone-depleting agent. Earthworms are a potential source of soil N₂O emissions. Application of biochar can mitigate earthworm-induced N₂O emissions. However, the underlying interactive mechanism between earthworms and biochar in soil N₂O emissions is still unclear. A 35-day laboratory experiment was conducted to examine the soil N₂O emission dynamics for four different treatments, earthworm presence with biochar application (EC), earthworm presence without biochar application (E), earthworm absence with biochar application (C) and earthworm absence without biochar application, and the control. Results indicated a negative impact of biochar on earthworm activity, displaying a significantly (p ≤ 0.05) lower survival rate and biomass of earthworms in treatment EC than E. Compared with the control, earthworm presence significantly (p ≤ 0.05) increased cumulative N₂O emissions, while application of biochar in the presence of earthworms significantly (p ≤ 0.05) decreased cumulative N₂O emissions (485 and 690 μg kg⁻¹ for treatments EC and E, respectively). Treatments E and EC significantly (p ≤ 0.05) increased soil microbial biomass carbon (MBC), ammonium (NH₄⁺-N), nitrate (NO₃⁻N), and dissolved organic carbon (DOC) content and soil pH as compared with the control. The gene copy number of 16 S rRNA, AOA, AOB, nirS, and nosZ increased for all treatments when compared with the control; however, a significant (p ≤ 0.05) difference among the studied genes was only observed for the nosZ gene (2.05 and 2.56 × 10⁶ gene copies g⁻¹ soil for treatments E and EC, respectively). Earthworm-induced soil N₂O emissions were significantly (p ≤ 0.05) reduced by biochar addition. The possible underlying mechanisms may include: (1) short-term negative impacts on earthworm activity; (2) a change of functional gene abundance in earthworm casts; and (3) an increase in soil pH due to addition of biochar.
Show more [+] Less [-]Estimations of benchmark dose for urinary metabolites of coke oven emissions among workers Full text
2021
Zou, Kaili | Wang, Sihua | Wang, Pengpeng | Duan, Xiaoran | Yang, Yongli | Yazdi, Mahdieh Danesh | Stowell, Jennifer | Wang, Yanbin | Yao, Wu | Wang, Wei
Coke oven emissions (COEs), usually composed of polycyclic aromatic hydrocarbons (PAHs) and so on, may alter the relative telomere length of exposed workers and have been linked with adverse health events. However, the relevant biological exposure limits of COEs exposure has not been evaluated from telomere damage. The purpose of this study is to estimate benchmark dose (BMD) of urinary PAHs metabolites from COEs exposure based on telomere damage with RTL as a biomarker. A total of 544 exposed workers and 238 controls were recruited for participation. High-performance liquid chromatography and qPCR were used to detect concentrations of urinary mono-hydroxylated PAHs and relative telomere length in peripheral blood leukocytes for all subjects. The benchmark dose approach was used to estimate benchmark dose (BMD) and its lower 95% confidence limit (BMDL) of urinary OH-PAHs of COEs exposure based on telomere damage. Our results showed that telomere length in the exposure group (0.75 (0.51, 1.08)) was shorter than that in the control group (1.05 (0.76,1.44))(P < 0.05), and a dose-response relationship was shown between telomere damage and both 1-hydroxypyrene and 3-hydroxyphenanthrene in urine. The BMDL of urinary 1-hydroxypyrene from the optimal model for telomere damage was 1.96, 0.40, and 1.01 (μmol/mol creatinine) for the total, males, and females group, respectively. For 3-hydroxyphenanthrene, the BMDL was 0.94, 0.33, and 0.49 (μmol/mol creatinine) for the total, males, and females. These results contribute to our understanding of telomere damage induced by COEs exposure and provide a reference for setting potential biological exposure limits.
Show more [+] Less [-]Hydrolyzed polyacrylamide-containing wastewater treatment using ozone reactor-upflow anaerobic sludge blanket reactor-aerobic biofilm reactor multistage treatment system Full text
2021
Song, Tianwen | Li, Shanshan | Yin, Zichao | Bao, Mutai | Lu, Jinren | Li, Yang
Polymer flooding is one of the most important enhanced oil recovery techniques. However, a large amount of hydrolyzed polyacrylamide (HPAM)-containing wastewater is produced in the process of polymer flooding, and this poses a potential threat to the environment. In this study, the treatment of HPAM-containing wastewater was analyzed in an ozonic-anaerobic-aerobic multistage treatment process involving an ozone reactor (OR), an upflow anaerobic sludge blanket reactor (UASBR), and an aerobic biofilm reactor (ABR). At an HPAM concentration of 500 mg L⁻¹ and an ozone dose of 25 g O₃/g TOC, the HPAM removal rate reached 85.06%. With fracturing of the carbon chain, high-molecular-weight HPAM was degraded into low-molecular-weight compounds. Microbial communities in bioreactors were investigated via high-throughput sequencing, which revealed that norank_c_Bacteroidetes_vadinHA17, norank_f_Cytophagaceae, and Meiothermus were the dominant bacterial groups, and that Methanobacterium, norank_c_WCHA1-57, and Methanosaeta were the key archaeal genera. To the best of our knowledge, this is the first study in which HPAM-containing wastewater is treated using an ozonic-anaerobic-aerobic multistage treatment system. The ideal degradation performance and the presence of keystone microorganisms confirmed that the multistage treatment process is feasible for treatment of HPAM-containing wastewater.
Show more [+] Less [-]The role of Nrf2 in mitigating cadmium-induced oxidative stress of Marsupenaeus japonicus Full text
2021
Ren, Xianyun | Xu, Yao | Yu, Zhenxing | Mu, Cuimin | Liu, Ping | Li, Jian
Nuclear factor-erythroid 2-related factor-2 (Nrf2) is an important modulator of cellular responses against Cd in mammalian cells. However, whether such modulation is conserved in Marsupenaeus japonicas remains unknown.In our study, the shrimps were injected with dsRNA targeting Nrf2 at 4 μg g⁻¹ body weight (b.w.) or sulforaphane (SFN) at 5 μg g⁻¹ b.w., and then were exposed to 40 mg L⁻¹ CdCl₂ for 48 h. After Nrf2 knockdown, the Cd content increased, but decreased in the SFN group. This suggested that Nrf2 could promote Cd excretion. A terminal deoxynulceotidyl transferase nick-end-labeling (TUNEL) assay revealed that the Nrf2 knockdown increased the number of apoptotic cells in M. japonicas, while SFN decreased the number of apoptotic cells. After Nrf2 knockdown, the total antioxidant capacity (T-AOC), superoxide dismutase (Sod) activity, and related gene expression decreased significantly, while the malondialdehyde (MDA) content increased remarkably. By contrast, SFN injection alleviated the oxidative stress, as evidenced by increased T-AOC, Sod activity, sod mRNA expression and a reduced MDA content. Similarly, detoxification related enzyme activities (ethoxyresorufin O-deethylase and glutathione-S-transferase (GST)) and their corresponding gene expressions (cyp3a (cytochrome P450 family 3 subfamily A) and gst) were suppressed in the ds-Nrf2 injection group, while they were elevated in the SFN group. In addition, ds-Nrf2 activated mitochondrial apoptotic pathway, as evidenced the mRNA and protein levels of caspase-3, Bcl2 associated X protein (Bax), and p53, while SFN treatment suppressed them. These results displayed that in M. japonicus Cd-induced cellular oxidative damage probably acts via the Nrf2 pathway.
Show more [+] Less [-]Long-term effects of Cu(OH)2 nanopesticide exposure on soil microbial communities Full text
2021
Peixoto, Sara | Henriques, Isabel | Loureiro, Susana
Copper-based (nano)pesticides in agroecosystems may result in unintended consequences on non-target soil microbial communities, due to their antimicrobial broad spectrum. We studied the impact of a commercial Cu(OH)₂-nanopesticide, over 90 days, at single and season agricultural application doses, in the presence and absence of an edaphic organism (the isopod Porcellionides pruinosus), on microbial communities’ function, structure and abundance. Results were compared to the effects of Cu(OH)₂-ionic. The nanopesticide application resulted in significant changes on both bacterial and fungal communities’ structure, particularly at the season application. The exposed bacterial community presented a significantly lower richness, and higher diversity and evenness while the exposed fungal community presented lower diversity and richness. At the functional level, a significant increase on microbial ability of carbon utilization and a significant decrease on the β−glucosidase activity was observed for communities exposed to the nanopesticide. Regarding Cu forms, less pronounced effects were observed in soils spiked with Cu(OH)₂-ionic, which might result from lower Cu concentration in porewater. The presence of P. pruinosus did not induce significant changes in diversity indexes (fungal community) and community-level physiological profiling, suggesting an attenuation of the nanopesticide effect. This study revealed that Cu(OH)₂-nanopesticide, at doses applied in agriculture, impact the soil microbial community, possibly affecting its ecological role. On the other hand, invertebrates may attenuate this effect, highlighting the importance of jointly including different interacting communities in the risk assessment of nanopesticides in soils.
Show more [+] Less [-]Episodes of high tropospheric ozone reduce nodulation, seed production and quality in soybean (Glycine max (L.) merr.) on low fertility soils Full text
2021
Biancari, Lucio | Cerrotta, Clara | Menéndez, Analía I. | Gundel, Pedro E. | Martínez-Ghersa, M Alejandra
Driven by human activities, air pollution and soil degradation are threatening food production systems. Rising ozone in the troposphere can affect several physiological processes in plants and their interaction with symbiotic microorganisms. Plant responses to ozone may depend on both soil fertility and the ontogenetic stage in which they are exposed. In this work, we studied the effects of ozone episodes and soil fertility on soybean plants. We analysed soybean plant responses in the production of aboveground and belowground biomass, structural and functional attributes of rhizobia, and seed production and quality. The experiment was performed with plants grown in two substrates with different fertility (commercial soil, and soil diluted (50%, v/v) with sand). Plants were exposed to acute episodes of ozone during vegetative and reproductive stages. We observed that ozone significantly reduced belowground biomass (≈25%), nodule biomass (≈30%), and biological nitrogen fixation (≈21%). Plants exposed to ozone during reproductive stage growing in soil with reduced fertility had lower seed production (≈10% lower) and seed protein (≈12% lower). These responses on yield and quality can be explained by the observed changes in belowground biomass and nitrogen fixation. The negative impact of ozone on the symbiotic interaction with rhizobia, seed production and quality in soybean plants were greater in soils with reduced fertility. Our results indicate that food security could be at risk in the future if trends in ozone concentration and soil degradation processes continue to increase.
Show more [+] Less [-]Release of inhalable particles and viable microbes to the air during packaging peeling: Emission profiles and mechanisms Full text
2021
Han, Ruining | Yu, Chenglin | Tang, Xuening | Yu, Song | Song, Min | Shen, Fangxia | Fu, Pingqing | Hu, Wei | Du, Lin | Wang, Xinfeng | Herrmann, Hartmut | Wu, Yan
Packaging is necessary for preserving and delivering products and has significant impacts on human health and the environment. Particle matter (PM) may be released from packages and transferred to the air during a typical peeling process, but little is known about this package-to-air migration route of particles. Here, we investigated the emission profiles of total and biological particles, and the horizontal and vertical dispersion abilities and community structure of viable microbes released from packaging to the air by peeling. The results revealed that a lot of inhalable particles and viable microbes were released from package to the air in different migration directions, and this migration can be regulated by several factors including package material, effective peeling area, peeling speed and angles, as well as the characteristics of the migrant itself. Dispersal of package-borne viable microbes provides direct evidence that viable microbes, including pathogens, can survive the aerosolization caused by peeling and be transferred to air over different distances while remaining alive. Based on the experimental data and visual proof in movies, we speculate that nonbiological particles are package fibers fractured and released to air by the external peeling force exerted on the package and that microbe dispersal is attributed to surface-borne microbe suspension by vibration caused by the peeling force. This investigation provides new information that aerosolized particles can deliver package-borne substances and viable microbes from packaging to the ambient environment, motivating further studies to characterize the health effects of such aerosolized particles and the geographic migration of microbes via packaging.
Show more [+] Less [-]Mitigating the toxic effects of CdSe quantum dots towards freshwater alga Scenedesmus obliquus: Role of eco-corona Full text
2021
Chakraborty, Debolina | Ethiraj, K.R. | Cantiracēkaran̲, Nā. | Mukherjee, Amitava
The extensive use of semiconducting nanoparticles such as quantum dots in biomedical and industrial products can lead to their inadvertent release into the freshwater system. Natural exudates in the aquatic system comprising extracellular polymeric substance (EPS) and protein-rich metabolites can eventually adsorb onto the quantum dots (QDs) surface and form an eco-corona. The alterations in the physio-chemical and toxicological behavior of CdSe/ZnS QDs under the influence of eco-corona in the freshwater system have not been explored yet. In the present study, lake water medium conditioned with exudate secreted by Scenedesmus obliquus was utilized as an eco-corona forming matrix. The time-based evolution of the eco-corona on the differently charged CdSe/ZnS QDs was analyzed using transmission electron microscopy and dynamic light scattering. Aging of amine-QDs in algal exudate for 72 h showed enhanced aggregation (Mean Hydrodynamic Diameter- 1969 nm) as compared to carboxyl-QDs (1543 nm). Further, eco-coronation tends to impart an overall negative charge to the QDs. The fluorescence intensity of amine-QDs was quenched by 84% due to the accumulation of higher eco-corona. An integrative effect of surface charge and accumulated eco-corona layer influenced the Cd²⁺ ion leaching from the QDs. An enhancement in the algal cell viability treated with carboxyl - CdSe/ZnS (90%) and amine- CdSe/ZnS QDs (94%) aged for 72 h suggested that eco-corona can effectively mitigate the inherent toxicity of the QDs. The oxidative stress markers in the algal cells (LPO, SOD, and CAT) were in correlation with the cytotoxicity results. The algal photosynthetic efficiency depended on the deposition of eco-coronated QDs on the cell surface. Cellular uptake results indicated low Cd²⁺ concentration of nearly 13.9 and 11.5% for carboxyl- and amine- CdSe/ZnS QDs respectively. This suggests that eco-coronation directly influences the bioavailability of engineered nanoparticles.
Show more [+] Less [-]A straightforward synthesis of visible light driven BiFeO3/AgVO3 nanocomposites with improved photocatalytic activity Full text
2021
Bavani, Thirugnanam | Madhavan, Jagannathan | Prasad, Saradh | AlSalhi, Mohamad S. | AlJaafreh, Mamduh J.
Herein, an efficient visible-light-driven BiFeO₃/AgVO₃ nanocomposite was effectively fabricated via a facile co-precipitation procedure. The physicochemical properties of BiFeO₃/AgVO₃ nanocomposites were investigated via Fourier transform-infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), UV visible diffuse reflectance spectroscopy (DRS) and photoelectrochemical studies (PEC). The photocatalytic activity (PCA) of BiFeO₃/AgVO₃ nanocomposites was assessed with regard to the photocatalytic degradation of Rhodamine-B (RhB) when subjected to visible light irradiation (VLI). Upon 90 min of illumination, the optimal 3%-BiFeO₃/AgVO₃ nanocomposite showed a greater photocatalytic degradation, which was ∼3 times higher than the bare AgVO₃. The lower PL intensity of 3%-BiFeO₃/AgVO₃ nanocomposite exposed the low recombination rate, which improved the photo-excited charge carriers separation efficiency. The experimental outcomes showed that the BiFeO₃/AgVO₃ nanocomposite might be an encouraging material for treatment of industrial and metropolitan wastewater. Moreover, a plausible RhB degradation mechanism was proposed proving the participation of the generated OH and O₂– radicals in the degradation over BiFeO₃/AgVO₃ nanocomposite.
Show more [+] Less [-]Pendimethalin induces apoptosis in testicular cells via hampering ER-mitochondrial function and autophagy Full text
2021
Ham, Jiyeon | Lim, Whasun | Song, Gwonhwa
Pendimethalin (PDM) is a dinitroaniline crop pesticide that is extensively utilized worldwide. However, the reproductive toxicity and cellular mechanisms of PDM have not been identified. Therefore, we elucidated the adverse effects of PDM on the reproductive system using mouse testicular Leydig and Sertoli cells (TM3 and TM4 cells, respectively). Our results demonstrated that PDM suppressed the viability and proliferation of TM3 and TM4 cells. Additionally, PDM induced cytosolic calcium upregulation and permeabilization of mitochondrial membrane potential in both TM3 and TM4 cells. We also verified that PDM activates the endoplasmic reticulum (ER) stress pathway and autophagy. Furthermore, we confirmed that activation of ER stress and autophagy were blocked by 2-aminoethoxydiphenyl borate (2-APB) treatment. Finally, we confirmed PDM-induced cell cycle arrest and apoptosis in TM3 and TM4 cells. Thus, we first demonstrated that PDM impedes the survival of testis cells, and further, their function.
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