Insights into growth stages and genotypes in airborne Pb accumulation in Oryza sativa L. grains: Utilizing isotope fingerprinting alongside a model study.

Atmospheric exposure is an important pathway of accumulation of lead (Pb) in Oryza sativa L. grains. In this study, source contributions of soil, early atmospheric exposure, and late atmospheric exposure, along with their bioaccumulation ratios were examined both in the pot and field experiments using stable Pb isotope fingerprinting technology combined with a three-compartment accumulation model. Furthermore, genotype differences in airborne Pb accumulation among four field-grown rice cultivars were investigated using the partial least squares path model (PLS-PM) linking rice Pb accumulation to agronomic traits. The findings revealed that during the late growth period, the air-foliar-grain transfer of Pb was crucial for rice Pb accumulation. Approximately 69-82% of the Pb found in polished rice was contributed by atmospheric source, with more than 80% accumulating during the late growth stage. The air accumulation ratios of rice grains were genotype-specific and estimated to be 0.364-1.062 m3/g during the late growth. Notably, grain size exhibited the highest standardized total effects on the airborne Pb concentrations in the polished rice, followed by leaf Pb and the upward translocation efficiency of Pb. The present study indicates that mitigating the health risks associated with Pb in rice can be achieved by controlling atmospheric Pb levels during the late growth stage and choosing Japonica inbred varieties characterized by large grain size.

Disparities and mechanisms of carbon and nitrogen conversion during food waste composting with different bulking agents.

The low C/N ratio, high moisture content, and low porosity of food waste require the addition of bulking agents for adjustment during the composting process. However, the effect and mechanism of different bulking agents on the reduction of carbon and nitrogen losses are unclear. Therefore, this study conducted experiments to evaluate and clarify the differences in carbon and nitrogen transformation between sawdust, rice husk and wheat bran in food waste composting. The results showed that the addition of bulking agents promoted the conversion of carbon and nitrogen into total organic carbon (TOC) and total organic nitrogen (TON) rather than CO2 and NH3. The carbon and nitrogen losses were reduced by 16.00-25.71% and 11.56-29.54%, respectively. Notably, the Sawdust group exhibited the highest carbon retention, whereas the Wheat_bran group demonstrated superior nitrogen retention. The succession of bacterial communities showed that sawdust enhanced the cellulolysis and xylanolysis functions while wheat bran promoted nitrogen fixation. Correlation analysis was further employed to speculate on potential interactions among carbon and nitrogen components. The incorporation of sawdust and rice husk improved humification partly due to the addition of lignocellulose and the accumulation of total dissolved nitrogen (DTN) in the substrate, respectively. In the process of ammonia assimilation, the addition of wheat bran promoted the accumulation of dissolved organic carbon (DOC), contributing to the synthesis of TON to a degree. These findings offer cost-effective strategies for conserving carbon and nitrogen from loss in food waste composting by selecting suitable bulking agents, ultimately producing high-quality fertilizer.

Microbiome-functionality in anaerobic digesters: A critical review.

Microbially driven anaerobic digestion (AD) processes are of immense interest due to their role in the biovalorization of biowastes into renewable energy resources. The function-versatile microbiome, interspecies syntrophic interactions, and trophic-level metabolic pathways are important microbial components of AD. However, the lack of a comprehensive understanding of the process hampers efforts to improve AD efficiency. This study presents a holistic review of research on the microbial and metabolic "black box" of AD processes. Recent research on microbiology, functional traits, and metabolic pathways in AD, as well as the responses of functional microbiota and metabolic capabilities to optimization strategies are reviewed. The diverse ecophysiological traits and cooperation/competition interactions of the functional guilds and the biomanipulation of microbial ecology to generate valuable products other than methane during AD are outlined. The results show that AD communities prioritize cooperation to improve functional redundancy, and the dominance of specific microbes can be explained by thermodynamics, resource allocation models, and metabolic division of labor during cross-feeding. In addition, the multi-omics approaches used to decipher the ecological principles of AD consortia are summarized in detail. Lastly, future microbial research and engineering applications of AD are proposed. This review presents an in-depth understanding of microbiome-functionality mechanisms of AD and provides critical guidance for the directional and efficient bioconversion of biowastes into methane and other valuable products.

Microbiome data analysis via machine learning models: Exploring vital players to optimize kitchen waste composting system.

Composting, reliant on microorganisms, effectively treats kitchen waste. However, it is difficult to precisely understand the specific role of key microorganisms in the composting process by relying solely on experimental research. This study aims to employ machine learning models to explore key microbial genera and to optimize composting systems. After introducing a novel microbiome preprocessing approach, Stacking models were constructed (R2 is about 0.8). The SHAP method (SHapley Additive exPlanations) identified Bacillus, Acinetobacter, Thermobacillus, Pseudomonas, Psychrobacter, and Thermobifida as prominent microbial genera (Shapley values ranging from 3.84 to 1.24). Additionally, microbial agents were prepared to target the identified key genera, and experiments demonstrated that the composting quality score was 76.06 for the treatment and 70.96 for the control. The exogenous agents enhanced decomposition and improved compost quality in later stages. In summary, this study opens up a new avenue to identifying key microorganisms and optimizing the biological treatment process.

Soil minerals and organic matters affect ARGs transformation by changing the morphology of plasmid and bacterial responses.

Soil environment is a vital place for the occurrence and spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Extracellular DNA-mediated transformation is an important pathway for ARGs horizontal transfer and widely exists in soil environment. However, little information is available on how common soil components affect ARGs transformation. Here, three minerals (quartz, kaolinite, and montmorillonite) and three organic matters (humic acid, biochar, and soot) were selected as typical soil components. A small amount in suspension (0.2 g/L) of most soil components (except for quartz and montmorillonite) promoted transformant production by 1.1-1.6 folds. For a high amount (8 g/L), biochar significantly promoted transformant production to 1.5 times, kaolinite exerted a 30 % inhibitory effect. From the perspective of plasmid, biochar induced a higher proportion of supercoiled plasmid than kaolinite; more dissolved organic matter and metal ions facilitated plasmid aggregation under the near-neutral pH, thus promoted transformation. As for the influence of materials on recipient, although biochar and kaolinite both increased reactive oxygen species (ROS) level and membrane permeability, biochar up-regulated more ROS related genes, resulting in intracellular ROS production and up-regulating the expression of carbohydrate metabolism and transformation related genes. While kaolinite inhibited transformation mainly by causing nutrient deficiency.

Soil Component: A Potential Factor Affecting the Occurrence and Spread of Antibiotic Resistance Genes.

In recent years, antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in soil have become research hotspots in the fields of public health and environmental ecosystems, but the effects of soil types and soil components on the occurrence and spread of ARGs still lack systematic sorting and in-depth research. Firstly, investigational information about ARB and ARGs contamination of soil was described. Then, existing laboratory studies about the influence of the soil component on ARGs were summarized in the following aspects: the influence of soil types on the occurrence of ARGs during natural or human activities and the control of exogenously added soil components on ARGs from the macro perspectives, the effects of soil components on the HGT of ARGs in a pure bacterial system from the micro perspectives. Following that, the similarities in pathways by which soil components affect HGT were identified, and the potential mechanisms were discussed from the perspectives of intracellular responses, plasmid activity, quorum sensing, etc. In the future, related research on multi-component systems, multi-omics methods, and microbial communities should be carried out in order to further our understanding of the occurrence and spread of ARGs in soil.

Conjugation-mediated transfer of antibiotic resistance genes influenced by primary soil components and underlying mechanisms.

Soil is the main natural reservoir of antibiotic resistant bacteria and antibiotic resistance genes (ARGs). Their dissemination and proliferation were largely motivated by conjugative transfer, while the influence of soil components on bacterial conjugative transfer and the underlying mechanisms remain poorly understood. In the present study, two Escherichia coli strains were exposed to soil minerals (quartz, kaolinite and montmorillonite) and organic matters (humic acid, biochar and soot) respectively to investigate their impact on ARGs conjugation. The results showed that quartz had no significant effect on conjugation; montmorillonite promoted the growth of the donor, but inhibited the recipient and conjugant; kaolinite and three organic matters significantly promoted the production of conjugant, while biochar promoted and then inhibited it with time prolong. Within the range of bacterial concentration involved in this study, the concentration of conjugant increased with the ratio of the concentration of donor and recipient (RD/R), indicating that the variation of conjugant production was mainly mediated by changing RD/R. Further observation of biochar treatment group showed that the bacterial responses such as cell membrane permeability, cell surface hydrophobicity and biofilm formation ability shifted with the exposure time, which might be a potential factor affecting conjugative transfer. Collectively, our findings suggest that the type and exposure time of soil components jointly affected conjugation, while the change of RD/R and related bacterial responses are the main underlying mechanisms.

Could sulfidation enhance the long-term performance of nano-zero valent iron in the peroxymonosulfate activation to degrade 2-chlorobiphenyl?

Sulfidation can enhance the hydrophobicity of nano-zero valent iron (nZVI) and improve its long-term degradation performance in reduction technology. However, whether sulfidation can enhance its long-term performance in sulfate radical-based advanced oxidation processes hasn't been systematically studied. Herein sulfide-modified nZVI (S-nZVI) was prepared by different sulfidation methods and S/Fe ratios. The behavior of S-nZVI on the peroxymonosulfatec (PMS) activation to degrade 2-chlorobiphenyl for continuous 5 rounds was investigated. The results showed that sulfidation couldn't always promote the long-term degradation performance. S-nZVI prepared by one-step sulfidation method with high S/Fe ratio (S-nZVIonestep-7%, S-nZVIonestep-14%) exhibited inferior degradation performance than unmodified nZVI (52.2%). This was because that the electron donor Fe0 was consumed rapidly and the crystalline lepidocrocite accumulated on the surface, thus inhibited PMS activation. In contrast, S-nZVI prepared by post-sulfidation method with high S/Fe ratio (S-nZVIpost-7%, S-nZVIpost-14%) exhibited more Fe0 residual, less FeOx accumulation, and more catalytic Fe2+ regeneration. Consequently, S-nZVIpost exhibited superior degradation capacity (69.3%). Moreover, the radical quenching experiments revealed that the primary free radicals involved in the degradation were transformed from SO4•- to •OH with prolongation of the degradation. Additionally, Fe (IV) contributed to the degradation through non-radical mechanism, especially in the S-nZVIpost-7%/PMS system.

Adsorption-reduction coupling mechanism and reductive species during efficient florfenicol removal by modified biochar supported sulfidized nanoscale zerovalent iron.

Sulfidized nanoscale zerovalent iron (S-nZVI) was a promising material for degrading halogenated contaminants, but the easy aggregation limits its application for in-situ groundwater remediation. Hence, S-nZVI was decorated onto modified biochar (mBC) to obtain better dispersity and reactivity with florfenicol (FF), a widely used antibiotic. Uniform dispersion of S-nZVI particles were achieved on the mBC with plentiful oxygen-containing functional groups and negative surface charge. Thus, the removal rate of FF by S-nZVI@mBC was 2.5 and 3.1 times higher than that by S-nZVI and S-nZVI@BC, respectively. Adsorption and dechlorination of FF showed synergistic effect under appropriate mBC addition (e.g., C/Fe mass ratio = 1:3, 1:1), probably due to the enrichment of FF facilitates its reduction. In contrast, the contact between FF and S-nZVI could be hindered under more mBC addition, significantly decrease the reduction rate of FF and the reduction capacity of per unit Fe0. In addition, sulfur dose altered the surface species of surface Fe and S, and removal rates of FF correlated well with surface reductive species, i.e., FeS (r = 0.90, p < 0.05) and Fe0 (r = 0.98, p < 0.01). These mechanistic insights indicate the importance of rational design for biochar supported S-nZVI, which can lead to more efficient FF degradation.

Exploring key physicochemical sediment properties influencing bioleaching of heavy metals.

Bioleaching is a promising technology to remediate sediments contaminated by heavy metals. However, the complex heterogeneities of the sediments can reduce the acidification efficiency and the heavy metal removal rate, thus hindering the practical application of sediment bioleaching. This experiment conducted comparative bioleaching experiments between the inoculated group (average leaching percentages: Cu 67.64%; Zn 54.44%; Ni 29.59%) and the non-inoculated control group (Cu 37.10%; Zn 41.04%; Ni 19.89%) on 28 sediments characterized by different physicochemical properties to explore the key factors influencing bioleaching. The results indicated that the bioleaching process was predominated by the indigenous bioleaching bacteria and the bioleaching inoculum, respectively. The ACCpH=4 (acid-consuming capacity), TOC (total organic carbon), and TN (total nitrogen) of the sediments played an essential role in influencing the microbial community structure and bioleaching performance: the ACCpH=4, as the inhibitive factor, could influence the succession growth of the indigenous bioleaching bacteria and the inoculum during the bioleaching process, while the TOC and TN, as the contributing factor, could influence the metabolism of the indigenous bioleaching bacteria. Based on these results, the bioleaching process was improved with the classification and pretreatments of sediment to realize successful bioleaching of all types of the sediments examined in this research.

INSM1 Expression in Mesenchymal Tumors and Its Clinicopathological Significance.

Background: Insulinoma-associated protein 1 (INSM1) has been identified as a nuclear marker of neuroendocrine tumors. Although INSM1 appears to be a subtle and specific biomarker for neuroendocrine tumor, its expression and clinicopathological significance in mesenchymal tumors remain unclear. Methods: We analyzed INSM1 mRNA level in GEO database and conducted immunohistological staining to detect the expression of INSM1 on 576 mesenchymal tumors from pathology department of Tongji Hospital. Results: At transcription level, INSM1 expression in AITL (angioimmunoblastic T-cell lymphoma) was higher than their adjacent normal tissues as well as Hodgkin's lymphoma. Moreover, INSM1 expression in well-differentiated liposarcoma (WDLPS) was significantly higher than normal fat (P = 0.014) and dedifferentiated liposarcoma (DDLPS) (P = 0.0248). At protein level, the positive rate of INSM1 in AITL was 18/48 (47.4%), while in DDLPS was 9/20 (45%). INSM1 expression in AITL was significantly higher than Hodgkin's lymphoma (P = 0.008). And INSM1 expression in WDLPS was significantly lower than DDLPS (P = 0.015). Conclusion: The combination of GEO data and immunohistochemistry data indicated that the expression level of INSM1 was higher in AITL compared with normal control, suggesting that INSM1 may be involved in pathogenesis of AITL. The abnormal expression of INSM1 was found in WDLPS, and the positive rate of INSM1 was higher in DDLPS than in WDLPS. INSM1 may be involved in the regulation of liposarcoma development. There were significant differences in the expression of INSM1 between AITL and Hodgkin's lymphoma and WDLPS and DDLPS. These findings may assist in the differential diagnosis of these tumors when common markers are difficult to identify, enriching the diagnostic index system of mesenchymal tumors.

Improving kitchen waste composting maturity by optimizing the processing parameters based on machine learning model.

As a novel analytical method based on big data, machine learning model can explore the relationship between different parameters and draw universal conclusions, which was used to predict composting maturity and identify key parameters in this study. The results showed that the Stacking model exhibited excellent prediction accuracy. SHapley Additive exPlanations (SHAP) and Partial Dependence Analysis (PDA) were performed to evaluate the importance of different parameters as well as their optimal interval. Optimal starting conditions should be maintained in the mesophilic state (temperature: 30-45℃, moisture content: 55-65%, pH: 6.3-8.0), and nutrients (total nitrogen > 2.3%, total organic carbon > 35%) should be adjusted in the thermophilic state. Experiments revealed that model-based optimization strategies could improve composting maturity because they could optimize compost microbial flora and perform complex carbon cycle functions. In conclusion, this study provides new insights into the enhancement of the composting process.

Potential threat of antibiotics resistance genes in bioleaching of heavy metals from sediment.

Bioleaching is considered a promising technology for remediating heavy metals pollution in sediments. During bioleaching, the pressure from the metals bioleached is more likely to cause the spread of antibiotic resistance genes (ARGs). The changes in abundance of ARGs in two typical heavy metal bioleaching treatments using indigenous bacteria or functional bacteria agent were compared in this study. Results showed that both treatments successfully bioleached heavy metals, with a higher removal ratio of Cu with functional bacteria agent. The absolute abundances of most ARGs decreased by one log unit after bioleaching, particularly tetR (p = 0.02) and tetX (p = 0.04), and intI1 decreased from 106 to 104 copies/g. As for the relative abundance, ARGs in the non-agent treatment increased from 3.90 × 10-4 to 1.67 × 10-3 copies/16S rRNA gene copies (p = 0.01), and in the treatment with agent, it reached 6.65 × 10-2 copies/16S rRNA gene copies, and intI1 relative abundance was maintained at 10-3 copies/16S rRNA gene copies. The relative abundance of ARGs associated with efflux pump mechanism and ribosomal protection mechanism increased the most. The co-occurrence network indicated that Cu bioleached was the environmental factor determining the distribution of ARGs, Firmicutes might be the potential hosts of ARGs. Compared to bioleaching with indigenous bacteria, the addition of functional bacteria agent engendered a decrease in microbial alpha diversity and an increase in the amount of Cu bioleached, resulting in a higher relative abundance of ARGs. Heavy metal pollution can be effectively removed from sediments using the two bioleaching treatments, however, the risk of ARGs propagation posed by those procedures should be considered, especially the treatment with functional bacteria agents. In the future, an economical and efficient green technology that simultaneously reduces both the absolute abundance and relative abundance of ARGs should be developed.

Airborne lead: A vital factor influencing rice lead accumulation in China.

Traditionally, lead (Pb) in rice grains has been thought to be mostly derived from soil, and the contribution of aerosol Pb remains so far unknown. Based on a meta-analysis, we surprisingly found rice Pb content decreased proportionally with urban atmospheric Pb concentrations in major rice-growing provinces in China during 2001-2015, suggestive of the strong influence of long-range Pb transport on agricultural environment. With the combination of field survey, field experiment, as well as a predictive model, we confirmed high contribution of atmospheric exposure to rice grain Pb in China. We for the first time developed a predictive mathematical model which revealed that aerosol Pb accumulation ratios of rice grains were related to both grain weight and accumulation types. We successfully predicted the national-scale rice Pb in China on the basis of the public data of urban PM2.5 from 19 rice-growing provinces and proposed a seasonal atmospheric Pb limit of 0.20 µg m-3 based on the safe threshold level of Pb in rice, which was much lower than the current limit of 1 µg m-3 set in China.

Neglected resistance risks: Cooperative resistance of antibiotic resistant bacteria influenced by primary soil components.

Various antibiotic resistant bacteria (ARB) can thrive in soil and resist such environmental pressures as antibiotics through cooperative resistance, thereby promoting ARB retention and antibiotic resistance genes transmission. However, there has been finite knowledge in regard to the mechanisms and potential ecological risks of cooperative resistance in soil microbiome. In this study, soil minerals and organic matters were designed to treat a mixture of two Escherichia coli strains with different antibiotic resistance (E. coli DH5α/pUC19 and E. coli XL2-Blue) to determine how soil components affected cooperative resistance, and Luria-Bertani plates containing two antibiotics were used to observe dual-drug resistant bacteria (DRB) developed via cooperative resistance. Results showed quartz, humic acid, and biochar promoted E. coli XL2-Blue with high fitness costs, whereas kaolin, montmorillonite, and soot inhibited both strains. Using fluorescence microscope and PCR, it was speculated DRB could resist the antibiotic pressure via E. coli XL2-Blue coating E. coli DH5α/pUC19. E. coli DH5α/pUC19 dominated cooperative resistance. Correlation analysis and scanning electron microscope images indicated soil components influenced cooperative resistance. Biochar promoted cooperative resistance by increasing intracellular reactive oxygen species, thereby reducing the dominant strain concentration required for DRB development. Kaolin inhibited cooperative resistance the most, followed by soot and montmorillonite.

The effect of black carbon on the chemical degradability of PCB1 via TENAX desorption technology from the perspective of adsorption states.

Chemical degradation is one of the crucial methods for the remediation of hydrophobic organic compounds (HOCs) in soil/sediment. The sequestration effect of black carbon (BC) can affect the adsorption state of HOCs, thereby affecting their chemical degradability. Our study focused on the chemical degradability of 2-Chlorobiphenyl (PCB1) sequestrated on the typical BC (fly ash (FC), soot (SC), low-temperature biochar (BC400) and high-temperature biochar (BC900)) by iron-nickel bimetallic nanomaterials (nZVI/Ni) based on TENAX desorption technology. The results showed that PCB1 adsorbed in various states were simultaneously dechlorinated by nZVI/Ni. Specifically, rapid-desorption-state PCB1 tended to degrade more easily than resistant-desorption-state PCB1. Moreover, the degradation mechanism varied according to the type of BC. In the case of FC and SC, the degradation rate was lower than the desorption rate for the PCB1 in rapid and slow desorption states, and the degradation rate of PCB1 in the resistant desorption state was negligible. The PCB1 on FC and SC was first desorbed from BC and then degraded. However, in terms of BC400 and BC900, the degradation rate was higher than the desorption rate, and the degradation rate of the resistant-desorption-state PCB1 was 1.4 × 10-2 h-1 and 4.1 × 10-2 h-1, respectively. The graphitized structure of BC900 can directly transfer electrons, so more than 90% of the resistant-desorption-state PCB1 could be degraded. In addition, BC may affect the longevity of nZVI/Ni, thereby affecting its degradability. Therefore, the chemical degradability of BC-adsorbed HOCs should be comprehensively evaluated based on the adsorption state and the properties of BC.

CNNM proteins selectively bind to the TRPM7 channel to stimulate divalent cation entry into cells.

Magnesium is essential for cellular life, but how it is homeostatically controlled still remains poorly understood. Here, we report that members of CNNM family, which have been controversially implicated in both cellular Mg2+ influx and efflux, selectively bind to the TRPM7 channel to stimulate divalent cation entry into cells. Coexpression of CNNMs with the channel markedly increased uptake of divalent cations, which is prevented by an inactivating mutation to the channel's pore. Knockout (KO) of TRPM7 in cells or application of the TRPM7 channel inhibitor NS8593 also interfered with CNNM-stimulated divalent cation uptake. Conversely, KO of CNNM3 and CNNM4 in HEK-293 cells significantly reduced TRPM7-mediated divalent cation entry, without affecting TRPM7 protein expression or its cell surface levels. Furthermore, we found that cellular overexpression of phosphatases of regenerating liver (PRLs), known CNNMs binding partners, stimulated TRPM7-dependent divalent cation entry and that CNNMs were required for this activity. Whole-cell electrophysiological recordings demonstrated that deletion of CNNM3 and CNNM4 from HEK-293 cells interfered with heterologously expressed and native TRPM7 channel function. We conclude that CNNMs employ the TRPM7 channel to mediate divalent cation influx and that CNNMs also possess separate TRPM7-independent Mg2+ efflux activities that contribute to CNNMs' control of cellular Mg2+ homeostasis.

Assessment and prediction of the effect of ageing on the adsorption of nonylphenol in black carbon-sediment systems.

Black carbon (BC) is a promising sediment amendment, as proven by its considerable adsorption capacity for hydrophobic organic pollutants and accessibility, but its reliability when used for the removal of pollutants in natural sediments still needs to be evaluated. For example, the ageing process, resulting in changing of surface physicochemical properties of BC, will decrease the adsorption capacity and performance of BC when applied to sediment pollution control. In this study, how the ageing process and BC proportion affect the adsorption capacity of BC-sediment systems was modelled and quantitatively investigated to predict their adsorption capacity under different ageing times and BC additions. The results showed that the ageing process decreased the adsorption capacity of both BC-sediment systems, due to the blockage of the non-linear adsorption sites of BC. The adsorption capacity of rice straw black carbon (RC)-sediment systems was higher than that of fly ash black carbon (FC)-sediment systems, indicating that RC is more efficient than FC for nonylphenol (NP) pollution control in sediment. The newly established model for the prediction of adsorption capacity fits the experimental data appropriately and yields acceptable predictions, especially when based on parameters from the Freundlich model. However, to fully reflect the influence of the ageing process on BC-sediment systems and make more precise predictions, it is recommended that future work considering more factors and conditions, such as modelling of the correlation between the adsorption capacity and the pore volume or specific surface area of BC, be applied to build an accurate and sound model.

Honokiol antagonizes doxorubicin resistance in human breast cancer via miR-188-5p/FBXW7/c-Myc pathway.

BACKGROUND: Honokiol, a natural phenolic compound derived from Magnolia plants, is a promising anti-tumor compound that exerts a wide range of anti-cancer effects. Herein, we investigated the effect of honokiol on doxorubicin resistance in breast cancer. METHODS: Doxorubicin-sensitive (MCF-7 and MDA-MB-231) and doxorubicin-resistant (MCF-7/ADR and MDA-MB-231/ADR) breast cancer cell lines were treated with doxorubicin in the absence or presence of honokiol; then, the following tests were performed: flow cytometry for cell apoptosis, WST-1 assay for cell viability, qPCR and western blot for the expression of miR-188-5p, FBXW7, and c-Myc. MiR-188-5p mimic, miR-188-5p inhibitor, siFBXW7, and c-Myc plasmids were transfected into cancer cells to evaluate whether miR-188-5p and FBXW7/c-Myc signaling are involved in the effect of honokiol on doxorubicin resistance in breast cancer. A dual luciferase reporter system was used to study the direct interaction between miR-188-5p and FBXW7. RESULTS: Honokiol sensitized doxorubicin-resistant breast cancer cells to doxorubicin-induced apoptosis. Mechanically, upregulation of miR-188-5p was associated with doxorubicin resistance, and honokiol enhanced doxorubicin sensitivity by downregulating miR-188-5p. FBXW7 was confirmed to be a direct target gene of miR-188-5p. FBXW7/c-Myc signaling was involved in the chemosensitization effect of honokiol. Honokiol induced apoptosis in MCF-7/ADR and MDA-MB-231/ADR cells. However, FBXW7 silencing or c-Myc transfection resulted in resistance to the honokiol-induced apoptotic effect. CONCLUSION: These findings suggest that downregulation of miR-188-5p by honokiol enhances doxorubicin sensitivity through FBXW7/c-Myc signaling in human breast cancer. Our study finds an important role of miR-188-5p in the development of doxorubicin resistance in breast cancer, and enriches our understanding of the mechanism of action of honokiol in cancer therapy.

The dominant effect of black carbon on the chemical degradability of PCB1: Sequestration or/and catalysis.

Black carbon (BC) plays a crucial role in the migration, transformation, and remediation of hydrophobic organics (HOCs) in soil/sediment. Previous studies mainly focus on the sorption characteristic of BC, while the chemical degradability of HOCs, which is affected by sequestration and catalytic effects of BC, has not yet been systematically studied. In this study, the dechlorination process of 2-chlorobiphenyl (PCB1), adsorbed on BC prepared at different pyrolysis temperatures, by bimetal modified nano zero-valent iron (nZVI/Pd) was investigated. The results showed that, on the one hand, adsorption limited the dechlorination process. PCB1 in the resistant desorption state exhibited lower degradation efficiency than that in other adsorption state. On the other hand, the catalysis of high-temperature BC reduced the inhibition of adsorption on dechlorination to some extent. As the pyrolysis temperature rose from 400 °C to 900 °C, the degradation efficiency of adsorbed PCB1 within 48 h improved from 53.5% to 95.3%, and the rate constant (kobs) increased from 0.104 h-1 to 0.197 h-1. High-temperature BC promoted the electrons release of Fe0 and the generation of [H], and its conductivity improved the electron utilization efficiency so that the dechlorination reaction could proceed both on the surface of nZVI/Pd particles and BC, thereby promoting the dechlorination of PCB1. Therefore, adsorption effect dominated degradability of PCB1 sequestrated by low-temperature BC, while for high-temperature BC, synergistic catalytic effect played a dominant role. These findings indicate that reductive efficiency of nZVI should be systematically evaluated according to different types of BC in soil/sediment.