•Factors affecting DnBP release from PVC microplastics were systematically studied.•More phthalate was released from microplastics with higher phthalate content.•Natural aging of plastics led to ...changed phthalate release.•Coexistence of fulvic acid and NaCl had a greater effect on phthalate release than fulvic acid alone.•Leaching of surface-active DOC from plastics could promote the release of phthalate plasticizer.
In recent years, great efforts have been made to understand the capacity of microplastics to adsorb environmental pollutants; however, relatively little is known about the ability of microplastics to release inherent additives into peripheral environments. In this study, we investigated the leaching behavior of phthalate plasticizer from polyvinyl chloride (PVC) microplastics, in aqueous solutions relevant to aquatic and soil environments. It was found that plastic properties, such as particle size, plasticizer content and aging of plastics had a great effect on the leaching of dibutyl phthalate (DnBP). Phthalate release was generally higher in smaller particles and particles with higher phthalate content. Whereas, plastic aging caused by solar irradiation could either enhance phthalate release by increasing plastic hydrophilicity or decrease the leaching by reducing readily available fractions of phthalate. Regarding environmental factors, solution pH (3–9) and ionic strength (0–0.2 M NaCl) were found to have minor effect on phthalate release, while fulvic acid (0–200 mg/L) greatly promoted the release by improving phthalate solubility and solution-plastic affinity. Interestingly, we found that more DnBP was leached out when fulvic acid and NaCl coexisted, and the results from dissolved organic carbon (DOC) and three-dimensional fluorescence spectroscopy analyzes suggested that the leaching of other fulvic acid-like additives might have played a role. These findings would be helpful for predicting the potential of microplastics to release toxic additives under different environmental conditions.
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Recently, the application of microbial fuel cells (MFCs) with cost-effective and long durable cathodic catalysts to generate electricity sustainably, has drawn much attention. This study investigated ...the use of nitrogen-doped carbon nanotubes (NCNTs) as the cathodic catalyst for oxygen reduction in MFCs to produce electricity efficiently and durably. The obtained maximum power density was 1600 +/- 50 mW m-2, which was higher than the commonly used platinum (Pt) catalyst (Pt/C) (1393 +/- 35 mW m-2). Also, the drop percentage of power densities with NCNTs was lower than with Pt/C over 25 cycles, indicating that MFCs with NCNTs as the cathodic catalyst could generate electricity more durably than those with Pt/C. Further investigation of the mechanisms revealed that MFCs with the bamboo-shaped and vertically aligned NCNTs had lower internal resistance and higher cathode potentials. Rotating ring-disk electrode voltammogram, Raman microspectroscopy and X-ray photoelectron spectroscopic analyses suggested that NCNTs possessed a higher electrocatalytic activity for the oxygen reduction reaction (ORR) via a four-electron pathway in neutral pH phosphate buffer solution (PBS). Cyclic voltammograms on NCNTs and Pt/C electrodes before and after a continuous potentiodynamic swept in neutral PBS demonstrated that NCNTs had a better durability for cathodic ORR than Pt/C, which drove MFCs with NCNTs to generate electricity durably.
Gibberellins (GAs) modulate jasmonate (JA) signaling, which is essential for stress response and development in plants. However, the molecular details of such phytohormone interaction remain largely ...unknown. Here, we show that the JA ZIM-domain 1 (JAZ1) protein, a key repressor of JA signaling, interacts in vivo with DELLA proteins, repressors of the GA pathway. DELLAs prevent inhibitory JAZ1 interaction with a key transcriptional activator of JA responses, MYC2, and, thus, enhance the ability of MYC2 to regulate its target genes. Conversely, GA triggers degradation of DELLAs, which allows JAZ1 to bind MYC2 and suppress MYC2-dependent JA-signaling outputs. Therefore, our results reveal one means by which GAs suppress cellular competence to respond to JA. Because DELLAs serve as central regulators that mediate the crosstalk of various phytohormones, our model also suggests a candidate mechanism by which JA signaling may be fine-tuned by other signaling pathways through DELLAs.
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► Gibberellins (GAs) inhibit DELLA-mediated upregulation of jasmonate (JA) target genes ► DELLAs compete the JA signaling repressor JAZ1 away from the JA effector MYC2 ► DELLA/JAZ binding derepresses MYC2's ability to regulate JA-responsive genes ► DELLAs promote cellular competence to respond to JA
► SCFA production from sludge and kitchen waste under alkaline conditions was optimized. ► The general microbial activity was enhanced under the optimum conditions. ► The activities of key enzymes ...reached the highest under the optimum conditions. ► The ratio of Bacteria to Archaea was improved under the optimum conditions. ► An excellent power output was achieved in MFCs fed with the fermentation liquid.
In a previous publication the conversion of waste activated sludge (WAS) to short-chain fatty acid (SCFA) was reported to be significantly enhanced by carbohydrate addition. Herein, the effect of carbon to nitrogen (C/N) ratio, pH (especially alkaline pH), temperature and hydraulic retention time (HRT) (or solid retention time (SRT)) on SCFA production and the related mechanisms were investigated when kitchen waste was added to WAS fermentation system. By response surface methodology, the conditions for maximal SCFA production were optimized, i.e. pH 8, C/N ratio 22, temperature 37°C and time 6d. Mechanism exploration revealed that under the optimum conditions the general activity of anaerobic microorganisms, the activities of key acid-forming enzymes, and the ratio of Bacteria to Archaea were improved remarkably, whereas the increase of methane production was negligible. With the fermentation liquid from WAS and kitchen waste as the fuel in microbial fuel cells (MFCs), the performance of electricity generation was enhanced significantly compared with those in MFCs fed with ultrasonic-pretreated WAS or ultrasonic-pretreated WAS plus smashed kitchen waste, due to the increase of SCFA content and the decrease of viscosity of the fuel.
is most broadly cultivated in the world due to its broader adaptation to the environment and successful breeding of early maturity varieties. However, how cotton responds to environmental cues to ...adjust flowering time to achieve reproductive success is largely unknown.
functions as an essential integrator for the endogenous and exogenous signals to maximize reproduction. Thus we identified six
-like genes in Gossypium that clustered into two groups.
contained a large intron and clustered with monocot
, while
3 were close to dicot
.
expression gradually increased during seedling development suggesting their conserved function in promoting flowering, which was supported by the early flowering phenotype of
lines and the delayed flowering of cotton silencing lines. Furthermore,
responded to short-day and high temperature conditions, while
responded to long-day conditions.
might function to promote flowering in response to low temperature and cold. Taken together, our results demonstrate that
respond differently to light and temperature and act cooperatively to activate
expression to promote floral transition and enlighten us in cotton adaptation to environment that is helpful in improvement of cotton maturity.
The control of environmental pollutants is a global concern. Recently, heteroatom-doped graphene has drawn increasing attention due to their widespread applications in removing and detecting ...environmental pollutants. Owing to the introduction of heteroatoms into pristine graphene, the properties of heteroatom-doped graphene have been significantly enhanced in physic, chemistry, and biology. This review focuses on the approaches for synthesis and characterization of boron-, sulfur-, and phosphorus-doped graphene and their applications in the fields of adsorption, catalysis, and detection for environmental pollutants. The mechanisms of environmental applications, including π–π interactions, complexation, hydrophobic interactions, electronic conductivity, and active sites and reactive radicals, are elaborated. Furthermore, the challenges associated with the use of heteroatom-doped graphene materials and their prospective applications are also proposed.
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•The synthesis and characterization of heteroatom-doped graphene are summarized.•Adsorption of organic pollutants, metals, etc., by doped graphene are discussed.•Great ability for catalytic degradation of pollutant by doped graphene is referred.•Good sensitivity for detecting contaminants by doped graphene is introduced.•Mechanisms for contaminants removal by doped graphene and prospects are proposed.
Zanthoxylum bungeanum seed oil (ZSO) with high free fatty acids (FFA) can be used for biodiesel production by ferric sulfate-catalyzed esterification followed by transesterification using calcium ...oxide (CaO) as an alkaline catalyst. Acid value of ZSO with high FFA can be reduced to less than 2
mg KOH/g by one-step esterification with methanol-to-FFA molar ratio 40.91:1, ferric sulfate 9.75% (based on the weight of FFA), reaction temperature 95
°C and reaction time 2
h, which satisfies transesterification using an alkaline catalyst. The response surface methodology (RSM) was used to optimize the conditions for ZSO biodiesel production using CaO as a catalyst. A quadratic polynomial equation was obtained for biodiesel conversion by multiple regression analysis and verification experiments confirmed the validity of the predicted model. The optimum combination for transesterification was methanol-to-oil molar ratio 11.69:1, catalyst amount 2.52%, and reaction time 2.45
h. At this optimum condition, the conversion to biodiesel reached above 96%. This study provided a practical method to biodiesel production from raw feedstocks with high FFA with high reaction rate, less corrosion, less toxicity, and less environmental problems.
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•Cancer stem cells (CSCs) are regarded as one of the important targets that mediate tumor resistance.•Tumor hypoxic microenvironment plays an important role in regulating resistance ...of CSCs to chemotherapy and radiotherapy.•Hypoxia maintains the stemness of CSCs through regulation of self-renewal signaling pathways, microRNAs, drug transporters and EMT.•HIFs have emerged as therapeutic targets in cancer therapy.
Drug resistance is a major obstacle in the treatment of tumors, which easily lead to relapse or poor prognosis. Cancer stem cells (CSCs) are regarded as one of the important targets that mediate tumor resistance. Increasing evidence shows that the tumor hypoxia microenvironment is closely related to the resistance of CSCs to chemotherapy and radiotherapy. In this review, we intend to review the articles that have described how the hypoxic microenvironment affects CSC stemness and mediates tumor resistance and provide new directions and methods in the clinical treatment of tumors. Here, we also discuss the feasibility and development prospects of using hypoxia-inducible factors (HIFs) that regulate the hypoxic microenvironment of tumors as targeted agents to treat tumors, as well as to reduce or even reverse the resistance of tumors to chemotherapy and radiotherapy.
Most of the reported studies on anaerobic fermentation of sludge focused on the influences of operating conditions, pretreatment methods, and its characteristics, and little attention was paid to ...those of persistent organic pollutants (POPs) which widespreadly appeared in sludge. In this study, the effect of nonylphenol, a typical POPs in waste activated sludge (WAS), on anaerobic fermentation for volatile fatty acids (VFAs) accumulation was investigated. The concentration of VFAs during WAS anaerobic fermentation was found to be affected positively from 2856 mg COD/L in the control (without NP) to 5620 mg COD/L with NP of 200 mg/kg dry sludge. Mechanism exploration exhibited that the main reason for the enhanced VFAs accumulation in the presence of NP was that more acetic acid was generated during the acidification of WAS, which was increased by almost three times (3790 versus 1310 mg COD/L). In WAS fermentation systems, the abundance of anaerobic functional microorganisms was advantageous to the accumulation of acetic acid. Further investigation by the pure acetogen revealed that both the viability and activity of Proteiniphilum acetatigenes were improved by NP during anaerobic fermentation, resulting in more production of acetic acid and showing good agreement with that in the real WAS fermentation systems.
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•WAS anaerobic fermentation was positively influenced by nonylphenol.•The production of VFAs, especially acetic acid was enhanced by nonylphenol.•NP stimulated WAS acidification but affected solubilization and hydrolysis little.•The microorganism abundance was advantageous to the accumulation of acetic acid.•The viability and activity of acetogen were improved in the presence of NP.
Hypoxic tumor microenvironment and maintenance of stemness contribute to drug resistance in breast cancer. However, whether Hypoxia-inducible factor-2α (HIF-2α) in hypoxic tumor microenvironment ...mediates conversion to a stem cell phenotype and chemoresistance of breast tumors has not been elucidated.
The mRNA and protein expressions of HIF-1α, HIF-2α, Wnt and Notch pathway were determined using qRT-PCR and western blot. Cell viability and renew ability were assessed by MTT, Flow cytometric analysis and soft agar colony formation.
In our study, acute hypoxia (6-12 h) briefly increased HIF-1α expression, while chronic hypoxia (48 h) continuously enhanced HIF-2α expression and induced the resistance of breast cancer cells to Paclitaxel (PTX). Furthermore, HIF-2α overexpression induced a stem cell phenotype, the resistance to PTX and enhanced protein expression of stem cell markers, c-Myc, OCT4 and Nanog. Most importantly, Wnt and Notch signaling, but not including Shh, pathways were both activated by HIF-2α overexpression. Dickkopf-1 (DKK-1), a Wnt pathway inhibitor, and L685,458, an inhibitor of the Notch pathway, reversed the resistance to PTX and stem phenotype conversion induced by HIF-2α overexpression. In addition, HIF-2α overexpression enhanced tumorigenicity and resistance of xenograft tumors to PTX, increased activation of the Wnt and Notch pathways and induced a stem cell phenotype in vivo.
In conclusion, HIF-2α promoted stem phenotype conversion and induced resistance to PTX by activating Wnt and Notch pathways.
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