Electronic Metal-Support Interactions between Copper Nanoparticles and Nitrogen-Doped Ti3C2Tx MXene to Boost Peroxidase-like Activity for Detecting Astaxanthin.

Nanozymes with high activity and stability have emerged as a potential alternative to natural enzymes in the past years, but the relationship between the electronic metal-support interactions (EMSI) and catalytic performance in nanozymes still remains unclear. Herein, a copper nanoparticle nanozyme supported on N-doped Ti3C2Tx (Cu NPs@N-Ti3C2Tx) is successfully synthesized and the modulation of EMSI is achieved by introducing N species. The stronger EMSI between Cu NPs and Ti3C2Tx, involving electronic transfer and an interface effect, is revealed by X-ray photoelectron spectroscopy, soft X-ray absorption spectroscopy, and hard X-ray absorption fine spectroscopy at the atomic level. Consequently, Cu NPs@N-Ti3C2Tx nanozyme exhibits remarkable peroxidase-like activity, surpassing its counterpart (Cu NPs, Ti3C2Tx, Cu NPs-Ti3C2Tx), suggesting that EMSI significantly enhances catalytic performance. Benefiting from the excellent performance, the colorimetric platform based on Cu NPs@N-Ti3C2Tx nanozyme for detecting astaxanthin is constructed and shows a wide linear detection range of 0.01-50 µM and a limit of detection of 0.015 µM in the sunscreens. Density functional theory is further conducted to reveal that the excellent performance is ascribed to the stronger EMSI. This work opens an avenue for studying the influence of EMSI toward catalytic performance of nanozyme.

Dithionite promoted microbial dechlorination of hexachlorobenzene while goethite further accelerated abiotic degradation by sulfidation in paddy soil.

It is of great scientific and practical importance to explore the mechanisms of accelerated degradation of Hexachlorobenzene (HCB) in soil. Both iron oxide and dithionite may promote the reductive dechlorination of HCB, but their effects on the microbial community and the biotic and abiotic mechanisms behind it remain unclear. This study investigated the effects of goethite, dithionite, and their interaction on microbial community composition and structure, and their potential contribution to HCB dechlorination in a paddy soil to reveal the underlying mechanism. The results showed that goethite addition alone did not significantly affect HCB dechlorination because the studied soil lacked iron-reducing bacteria. In contrast, dithionite addition significantly decreased the HCB contents by 44.0-54.9%, while the coexistence of dithionite and goethite further decreased the HCB content by 57.9-69.3%. Random Forest analysis suggested that indicator taxa (Paenibacillus, Acidothermus, Haliagium, G12-WMSP1, and Frankia), Pseudomonas, richness and Shannon's index of microbial community, and immobilized Fe content were dominant driving factors for HCB dechlorination. The dithionite addition, either with or without goethite, accelerated HCB anaerobic dechlorination by increasing microbial diversity and richness as well as the relative abundance of the above specific bacterial genera. When goethite and dithionite coexist, sulfidation of goethite with dithionite could remarkably increase FeS formation and then further promote HCB dechlorination rates. Overall, our results suggested that the combined application of goethite and dithionite could be a practicable strategy for the remediation of HCB contaminated soil.

[Input Characteristics of Dry Deposition of Atmospheric Particulates and Metals in Farmland in the Suburb of Nanjing].

The dry deposition of heavy metals in atmospheric particulates is one of the important sources of heavy metals in agricultural areas, but there are few observational studies on the atmospheric deposition of heavy metals in agricultural areas. In this study, the concentrations of atmospheric particulates with different particle sizes and ten kinds of metal elements in them were analyzed by sampling a typical rice-wheat rotation area in the suburb of Nanjing for one year, and the dry deposition fluxes were estimated using the big leaf model, so as to understand the input characteristics of particulates and heavy metals. The results showed that the particulate concentrations and dry deposition fluxes were high in winter and spring but low in summer and autumn. In winter and spring, coarse particulates (2.1-9.0 µm) and fine particulates (<2.1 µm) had dual effects on particulate pollution, whereas in summer and autumn, particulate pollution was mainly attributed to the fine particulates. The concentrations of metal elements were the lowest in giant particulates (>9.0 µm) and were similar in coarse particulates and fine particulates, whereas Pb, Mn, As, and Cd elements were relatively high in fine particulates. The average annual dry deposition fluxes[g·(m2·a)-1] of particulates was giant particulates (8.31)>coarse particulates (5.99)>fine particulates (0.629). The order of average annual dry deposition fluxes[mg·(m2·a)-1] of the 10 metals was Ca(2096.4)>Al(1710.4)>Zn(855.0)>Fe(256.1)>Pb(40.35)>Cu(31.93)>V(26.21)>Mn(9.10)>As(2.48)>Cd(0.28). The average annual dry deposition fluxes of the 10 metal elements in fine particulates, coarse particulates, and giant particulates were 179.03, 2124.97, and 2724.18 mg·(m2·a)-1, respectively. These results will provide a reference for a more comprehensive understanding of the impact of human activities on the quality and safety of agricultural products and soil ecological environment.

Spatiotemporal Dynamics of Carbon Footprint of Main Crop Production in China.

As a major agricultural country, the comprehensive accounting of the dynamics and composition of the carbon footprint of major crops in China will provide a decision-making basis for environmental management and agricultural green development in the whole process of the major crop production system in China. To investigate the spatiotemporal dynamics of the carbon footprint for major crops in China, a life cycle-based carbon footprint approach was used to evaluate the carbon footprint per unit area (CFA) and per unit yield (CFY) of eight crops for the period of 1990 to 2019. Our results showed that the CFA for all major crops showed an increasing trend with time before 2016 but slowly decreased afterward, while the CFY decreased by 16-43% over the past 30 years due to the increase in crop yield. The three main grain crops, rice (4871 ± 418 kg CO2-eq · ha-1), wheat (2766 ± 552 kg CO2-eq · ha-1), and maize (2439 ± 530 kg CO2-eq · ha-1), showed the highest carbon footprint and contribution to the total greenhouse gas (GHG) emissions, mainly due to their larger cultivated areas and higher fertilizer application rates. CH4 emission was the major component of the carbon footprint for rice production, accounting for 66% and 48% of the CFA and CFY, respectively, while fertilizer production and usage were the largest components of carbon footprint for dryland crops, making up to 26-49% of the CFA and 26-50% of the CFY for different crops. The present study also highlighted the spatial and temporal patterns of the carbon footprint for major crops in China, which could serve as references for the development of best management practices for different crop production in China, to mitigate agricultural GHG emission and to pursue low-carbon agriculture.

Life Cycle Assessment on Agricultural Production: A Mini Review on Methodology, Application, and Challenges.

Agricultural Life Cycle Assessment (LCA) is an effective tool for the quantitative evaluation and analysis of agricultural materials production and operation activities in various stages of the agricultural system. Based on the concept of life cycle, it comprehensively summarizes the impact of agriculture on the environment, which is an effective tool to promote the sustainability and green development of agriculture. In recent years, agricultural LCA has been widely used in the agroecosystem for resource and environmental impacts analysis. However, some challenges still exist in agricultural LCA, i.e., the environmental impact assessment index system needs to be improved; its application in different production mode is limited; and combination research with other models needs more attention. This paper discusses the above-mentioned challenges and recommends research priorities for both scientific development and improvements in practical implementation. In summary, further research is needed to construct a regional heterogeneity database and develop innovated methodologies to develop more meaningful functional units for agricultural products to complement LCA by other models. These efforts will make agricultural LCA more robust and effective in environmental impacts assessment to support decision making from individual farm to regional or (inter)national for the sustainable future of agriculture.

Atomically dispersed Pd catalysts promote the oxygen evolution reaction in acidic media.

A Pd-doped Pt3Sn-based single atom alloy catalyst (Pd-Pt3Sn) was synthesized via a hydrothermal method. The overpotential of Pd-Pt3Sn is lower than that of commercial Pd/C and IrO2 catalysts at 10 mA cm-2. This is due to the synergistic effect between Pt, Sn and Pd and the influence of electronic effects on their catalytic performance.

Biochar-Polylactic Acid Composite Accelerated Reductive Dechlorination of Hexachlorobenzene in Paddy Soils under Neutral pH Condition.

In order to clarify the effect of biochar-polylactic acid (PLA) composite on reductive dechlorination of HCB in paddy soils, an anaerobic incubation experiment was conducted with four treatments of Sterile control, Control, Biochar, and Biochar-PLA in Hydragric Acrisols (Ac) and Gleyi-Stagnic Anthrosols (An). The results showed that in Ac, biochar addition significantly promoted HCB degradation during the whole incubation period, but biochar-PLA composite inhibited HCB dechlorination due to the low soil pH in the early period and then accelerated HCB degradation while soil pH climbed to nearly neutral. The dechlorination rate of HCB in An was: Biochar-PLA > Biochar > Control > Sterilization control. The degradation rate of HCB in An was faster than in Ac, due to the higher iron content and neutral pH condition in An. The results indicated that biochar-PLA composite promoted the reductive dechlorination of HCB efficiently in paddy soil under nearly neutral pH condition.

Effects of nitrogen deposition and litter layer management on soil CO2, N2O, and CH4 emissions in a subtropical pine forestland.

Forestland soils play vital role in regulating global soil greenhouse gas (GHG) budgets, but the interactive effect of the litter layer management and simulated nitrogen (N) deposition on these GHG flux has not been elucidated clearly in subtropical forestland. A field trial was conducted to study these effects by using litter removal method under 0 and 40 kg N ha-1 yr-1 addition in a subtropical forestland in Yingtan, Jiangxi Province, China. Soil CO2 emission was increased by N addition (18-24%) but decreased by litter removal (24-32%). Litter removal significantly (P < 0.05) decreased cumulative N2O emission by 21% in treatments without N addition but only by 10% in treatments with 40 kg N ha-1 yr-1 addition. Moreover, litter-induced N2O emission under elevated N deposition (0.094 kg N2O-N ha-1) was almost the same as without N addition (0.088 kg N2O-N ha-1). Diffusion of atmospheric CH4 into soil was facilitated by litter removal, which increased CH4 uptake by 55%. Given that the increasing trend of atmospheric N deposition in future, which would reduce litterfall in subtropical N-rich forest, the effect of surface litter layer change on soil GHG emissions should be considered in assessing forest GHG budgets and future climate scenario modeling.

Nitrogen and phosphorus enrichment accelerates soil organic carbon loss in alpine grassland on the Qinghai-Tibetan Plateau.

Anthropogenic activities have substantially increased soil nutrient availability, which in turn affects ecosystem processes and functions, especially in nutrient-limited ecosystems such as alpine grasslands. Although considerable efforts have been devoted to understanding the responses of plant productivity and community composition to nitrogen (N) and phosphorus (P) enrichment, the nutrient enrichment effects on soil organic carbon (SOC) and microbial functions are not well understood. A four-year field experiment was established to evaluate the influence of continuous N and P enrichment on plant growth and SOC content in an alpine grassland of the Qinghai-Tibetan Plateau. The study included four treatments: Control without addition, N addition, P addition, and N plus P addition. N addition strongly increased aboveground plant biomass and decreased species richness by promoting growth of the dominant grasses species. In contrast, N and P enrichment significantly decreased SOC, especially the recalcitrant organic C content in the surface layer (0-10 cm) by reducing the slow C pool and enlarging the active C pool. Microbial biomass and activities of C-degrading enzymes (ß-glucosidase, cellulase and polyphenol oxidase) and an N-degrading enzyme (chitinase) increased with nutrient inputs. The CO2 emissions during a 300 d incubation period were positively correlated with the cellulase and chitinase activities, while the slow C pool was negatively correlated with the cellulase and polyphenol oxidase activities. Consequently, N and P enrichment accelerated decomposition of the recalcitrant C by stimulating microbial growth and increasing enzyme activities, leading to negative impacts on soil C sequestration. Overall, the results indicate that alpine grassland soils of the Qinghai-Tibetan Plateau may be changing from a C sink to a C source under increasing N and P availability, and improvement of alpine grassland management through nutrient inputs should consider not only the aboveground biomass for grazing, but also the soil C sequestration and ecosystem functioning.

Effect of application of dairy manure, effluent and inorganic fertilizer on nitrogen leaching in clayey fluvo-aquic soil: A lysimeter study.

Dairy farm manure and effluent are applied to cropland in China to provide a source of plant nutrients, but there are concerns over its effect on nitrogen (N) leaching loss and groundwater quality. To investigate the effects of land application of dairy manure and effluent on potential N leaching loss, two lysimeter trials were set up in clayey fluvo-aquic soil in a winter wheat-summer maize rotation cropping system on the North China Plain. The solid dairy manure trial included control without N fertilization (CK), inorganic N fertilizer (SNPK), and fresh (RAW) and composted (COM) dairy manure. The liquid dairy effluent trial consisted of control without N fertilization (CF), inorganic N fertilizer (ENPK), and fresh (FDE) and stored (SDE) dairy effluent. The N application rate was 225kgNha-1 for inorganic N fertilizer, dairy manure, and effluent treatments in both seasons. Annual N leaching loss (ANLL) was highest in SNPK (53.02 and 16.21kgNha-1 in 2013/2014 and 2014/2015, respectively), which were 1.65- and 2.04-fold that of COM, and 1.59- and 1.26-fold that of RAW. In the effluent trial (2014/2015), ANLL for ENPK and SDE (16.22 and 16.86kgNha-1, respectively) were significantly higher than CF and FDE (6.3 and 13.21kgNha-1, respectively). NO3- contributed the most (34-92%) to total N leaching loss among all treatments, followed by dissolved organic N (14-57%). COM showed the lowest N leaching loss due to a reduction in NO3- loss. Yield-scaled N leaching in COM (0.35kgNMg-1 silage) was significantly (P<0.05) lower than that in the other fertilization treatments. Therefore, the use of composted dairy manure should be increased and that of inorganic fertilizer decreased to reduce N leaching loss while ensuring high crop yield in the North China Plain.

Responses of manure decomposition to nitrogen addition: Role of chemical composition.

Understanding the interactions among organic manure chemical composition, decomposition and nitrogen (N) fertilization is critical for sustainable agriculture management. Six organic manures were incubated in a cultivated black soil with or without N addition for one year, and carbon dioxide (CO2) emissions from these organic manures were monitored. Chemical compositions of the organic manures were determined by elemental analysis, proximate chemical analysis, and carbon (C)-13 nuclear magnetic resonance spectroscopy, and evaluated after cupric-oxide oxidation for lignin biomarkers. During the experimental period, 19-44% of manure C was decomposed without N addition, which decreased to 17-35% with N addition, except for the composted furfural residue with rice dregs. However, during different decomposition stages, N effect changed from stimulation to inhibition, or behaved as increasing inhibition. During stage 1 (days 0-100) when N stimulation effect reached a maximum, CO2 emissions from manure had positive relationships with labile C fraction indicators, including total sugars, soluble polyphenols, and lignin cinnamyl/vanillyl ratio regardless of N addition. N effect on manure decomposition was related to the C/N ratio and labile organic C content. During stage 2 (days 101-267), N effect shifted to inhibition, with CO2 emissions from manure negatively related to lignin vanillyl-units content. The magnitude of N inhibition increased linearly with the aromaticity of dissolved organic C, and was strengthened by nitrate in manure. Finally, N inhibition effect reached a maximum during stage 3 (days 268-365), increasing with higher aromatic C in manure. Critical factors for manure decomposition shifted from total sugars, soluble polyphenols, and lignin cinnamyl-units to recalcitrant lignin vanillyl-units and aromatic C fraction, which mediated the type and magnitude of N effect on decomposition. Our results suggested that the potential for enhancing soil C sequestration with organic manures would magnify under combined application with N fertilizer in the long term.

Extreme rainfall and snowfall alter responses of soil respiration to nitrogen fertilization: a 3-year field experiment.

Extreme precipitation is predicted to be more frequent and intense accompanying global warming and may have profound impacts on soil respiration (Rs) and its components, that is, autotrophic (Ra) and heterotrophic (Rh) respiration. However, how natural extreme rainfall or snowfall events affect these fluxes are still lacking, especially under nitrogen (N) fertilization. In this study, extreme rainfall and snowfall events occurred during a 3-year field experiment, allowing us to examine their effects on the response of Rs, Rh, and Ra to N supply. In normal rainfall years of 2011/2012 and 2012/2013, N fertilization significantly stimulated Rs by 23.9% and 10.9%, respectively. This stimulation was mainly due to the increase of Ra because of N-induced increase in plant biomass. In the record wet year of 2013/2014, however, Rs was independent on N supply because of the inhibition effect of the extreme rainfall event. Compared with those in other years, Rh and Ra were reduced by 36.8% and 59.1%, respectively, which were likely related to the anoxic stress on soil microbes and decreased photosynthates supply. Although N supply did not affect annual Rh, the response ratio (RR) of Rh flux to N fertilization decreased firstly during growing season, increased in nongrowing season and peaked during spring thaw in each year. Nongrowing season Rs and Rh contributed 5.5-16.4% to their annual fluxes and were higher in 2012/2013 than other years due to the extreme snowfall inducing higher soil moisture during spring thaw. The RR of nongrowing season Rs and Rh decreased in years with extreme snowfall or rainfall compared to those in normal years. Overall, our results highlight the significant effects of extreme precipitation on responses of Rs and its components to N fertilization, which should be incorporated into models to improve the prediction of carbon-climate feedbacks.

Grazing improves C and N cycling in the Northern Great Plains: a meta-analysis.

Grazing potentially alters grassland ecosystem carbon (C) and nitrogen (N) storage and cycles, however, the overall direction and magnitude of such alterations are poorly understood on the Northern Great Plains (NGP). By synthesizing data from multiple studies on grazed NGP ecosystems, we quantified the response of 30 variables to C and N pools and fluxes to grazing using a comprehensive meta-analysis method. Results showed that grazing enhanced soil C (5.2 ± 4.6% relative) and N (11.3 ± 9.1%) pools in the top layer, stimulated litter decomposition (26.8 ± 18.4%) and soil N mineralization (22.3 ± 18.4%) and enhanced soil NH4(+) (51.5 ± 42.9%) and NO3(-) (47.5 ± 20.7%) concentrations. Our results indicate that the NGP grasslands have sequestered C and N in the past 70 to 80 years, recovering C and N lost during a period of widespread grassland deterioration that occurred in the first half of the 20(th) century. Sustainable grazing management employed after this deterioration has acted as a critical factor for C and N amelioration of degraded NGP grasslands and about 5.84 Mg C ha(-1) CO2-equivalent of anthropogenic CO2 emissions has been offset by these grassland soils.

[Efficacy and prognostic factors of induction therapy combined with autologous stem cell transplantation in 201 patients with multiple myeloma].

OBJECTIVE: To explore the efficacy and prognostic factors of induction therapy combined with autogenetic peripheral blood stem cells transplantation (APBSCT)in patients with multiple myeloma (MM). METHODS: From January 1998 to May 2015, 201 patients with MM were enrolled. All patients received APBSCT after induction therapy. With the follow up to 20 June 2015, the overall survival (OS), progression free survival (PFS)and prognostic factor were analyzed. RESULTS: ① With a media follow up of 36.67 months, the median PFS and OS were 22.87 (17.48- 28.26)and 69.63 (63.57- 75.69)months, 5-year PFS and OS were 17% and 49%, respectively. ②After APBSCT, when the subgroup (n= 112) achieved complete response (CR)compared with the subgroup (n=89) not achieved CR, the median PFS were 32.93 (21.03-44.83) and 18.13 (14.46-21.80) months (P<0.001), respectively; And the media OS were 96.77 (71.79- 121.75)and 54.70 (49.53- 59.87) months (P=0.004), respectively. The risks for disease progression and death declined in CR subgroup. ③ Two subgroups included or not included bortezomib/thalidomide at induction therapy (123 patientsvs 21 patients), the media PFS were 31.67 (24.36- 38.98)and 15.20 (10.11- 20.29) months (P=0.013), respectively; And the media OS were 76.30 (55.44- 97.15)and 52.03 (33.76- 70.30) months (P=0.014), respectively. ④According to the ISS stage, the media OS of stageⅠ, Ⅱ, Ⅲ were 99.47 (59.58-139.36), 66.77 (52.17-81.37), 53.97 (28.71-79.23) (P< 0.001), respectively. The risk for death of stage Ⅱ, Ⅲ were 2.16 and 3.04 times higher than stage Ⅰ, with no difference in terms of PFS. ⑤ The media PFS in IgD (n=22) and IgG (n=101) type MM were 11.17 (10.27- 13.13)and 35.43 (22.69- 48.17)months (P=0.007) , respectively; The media OS were 30.83 (0.24-61.42)and 70.70 (53.52-87.88) months (P=0.039), respectively. The risk for disease progression of IgD type was 2.47 times higher than IgG type. ⑥ Patients received 1 line induction therapy (n=132) compared with more than 1 line (n=69), the media PFS were 25.43 (16.09- 34.77)and 20.27 (15.04- 25.50) months (P=0.042). ⑦Cox analysis showed that CR after APBSCT and ISS stage were independent prognostic factors for OS. IgD type MM and CR after APBSCT were independent prognosis factor for PFS. CONCLUSION: CR after APBSCT and ISS stage were independent prognostic factors for OS in MM. CR after APBSCT was independent prognostic factor for PFS in MM. However, disease progression more likely occurred in IgD type MM, which was independent negative prognostic factor for PFS in MM.

Electron Donor Substances and Iron Oxides Stimulate Anaerobic Dechlorination of DDT in a Slurry System with Hydragric Acrisols.

The interactive effects between electron donor substances and iron (Fe) oxides have significant influence on electron transfer and the growth of Fe-reducing bacteria, which may affect the reductive dechlorination of 1,1,1-trichoro-2,2-bis(p-chlorophenyl)ethane (DDT) in soils. To evaluate the roles of volatile fatty acids and Fe(III) oxide in accelerating the reductive dechlorination of DDT in Hydragric Acrisols, a batch anaerobic incubation experiment was conducted in a slurry system with the following seven treatments: sterile soil, control (DDT-contaminated soil), lactic acid, propionic acid, goethite, lactic acid + goethite, and propionic acid + goethite. Results showed that after 20 d of incubation, DDT residues for these treatments decreased by 34, 65, 77, 81, 77, 90, and 92% of the initial quantities, respectively, with 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethane as the dominant metabolite. The application of lactic acid had no significant effect on DDT dechlorination in the first 8 d while the methanogenesis rate increased quickly but accelerated DDT dechlorination after Day 8 while the methanogenesis rate decreased and Fe(II) contents increased. The application of propionic acid enhanced DDT dechlorination rates throughout the incubation. The amendment by goethite stimulated microbial reduction of Fe(III) oxides to generate Fe(II), which was an efficient electron donor, thus accelerating DDT dechlorination significantly in the early incubation period. A synergetic interaction that accelerated DDT dechlorination, either between lactic acid and goethite or between propionic acid and goethite, was obtained. The results will be of great significance to develop efficient in situ remediation technology of DDT-contaminated soil.

Accelerated anaerobic dechlorination of DDT in slurry with Hydragric Acrisols using citric acid and anthraquinone-2,6-disulfonate (AQDS).

The application of electron donor and electron shuttle substances has a vital influence on electron transfer, thus may affect the reductive dechlorination of 1,1,1-trichoro-2,2-bis(p-chlorophenyl)ethane (DDT) in anaerobic reaction systems. To evaluate the roles of citric acid and anthraquinone-2,6-disulfonate (AQDS) in accelerating the reductive dechlorination of DDT in Hydragric Acrisols that contain abundant iron oxide, a batch anaerobic incubation experiment was conducted in a slurry system with four treatments of (1) control, (2) citric acid, (3) AQDS, and (4) citric acid+AQDS. Results showed that DDT residues decreased by 78.93%-92.11% of the initial quantities after 20days of incubation, and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethane (DDD) was the dominant metabolite. The application of citric acid accelerated DDT dechlorination slightly in the first 8days, while the methanogenesis rate increased quickly, and then the acceleration effect improved after the 8th day while the methanogenesis rate decreased. The amendment by AQDS decreased the Eh value of the reaction system and accelerated microbial reduction of Fe(III) oxides to generate Fe(II), which was an efficient electron donor, thus enhancing the reductive dechlorination rate of DDT. The addition of citric acid+AQDS was most efficient in stimulating DDT dechlorination, but no significant interaction between citric acid and AQDS on DDT dechlorination was observed. The results will be of great significance for developing an efficient in situ remediation strategy for DDT-contaminated sites.

MicroRNA-451 regulates stemness of side population cells via PI3K/Akt/mTOR signaling pathway in multiple myeloma.

Side population (SP) cells are an enriched source of cancer-initiating cells with stemness characteristics, generated by increased ABC transporter activity, which has served as a unique hallmark for multiple myeloma (MM) stem cell studies. Here we isolated and identified MM SP cells via Hoechst 33342 staining. Furthermore, we demonstrate that SP cells possess abnormal cell cycle, clonogenicity, and high drug efflux characteristics-all of which are features commonly seen in stem cells. Interestingly, we found that bortezomib, As2O3, and melphalan all affected apoptosis and clonogenicity in SP cells. We followed by characterizing the miRNA signature of MM SP cells and validated the specific miR-451 target tuberous sclerosis 1 (TSC1) gene to reveal that it activates the PI3K/Akt/mTOR signaling in MM SP cells. Inhibition of miR-451 enhanced anti-myeloma novel agents' effectiveness, through increasing cells apoptosis, decreasing clonogenicity, and reducing MDR1 mRNA expression. Moreover, the novel specific PI3K/Akt/mTOR signaling inhibitor S14161 displayed its prowess as a potential therapeutic agent by targeting MM SP cells. Our findings offer insights into the mechanisms regulating MM SP cells and provide a novel strategy to overcome resistance to existing therapies against myeloma.

Epigenetic modification of MiR-429 promotes liver tumour-initiating cell properties by targeting Rb binding protein 4.

OBJECTIVE: Liver tumour-initiating cells (T-ICs) are critical for hepatocarcinogenesis. However, the underlying mechanism regulating the function of liver T-ICs remains unclear. METHODS: Tissue microarrays containing 242 hepatocellular carcinoma (HCC) samples were used for prognostic analysis. Magnetically activated cell sorting was used to isolate epithelial cell adhesion molecule (EPCAM)-positive cells. The gene expressions affected by miR-429 were determined by arrays. Co-immunoprecipitation was used to study interactions among retinoblastoma protein (RB1), Rb binding protein 4 (RBBP4) and E2F transcription factor 1 (E2F1). The DNA methylation status in CpG islands was detected by quantitative methylation analysis. miRNAs in microvesicles were isolated by a syringe filter system. RESULTS: The significant prognosis factor miR-429 was upregulated in HCC tissues and also in primary liver T-ICs isolated from clinical samples. The enrichment of miR-429 in EPCAM+ T-ICs contributed to hepatocyte self-renewal, malignant proliferation, chemoresistance and tumorigenicity. A novel functional axis involving miR-429, RBBP4, E2F1 and POU class 5 homeobox 1 (POU5F1 or OCT4) governing the regulation of liver EPCAM+ T-ICs was established in vitro and in vivo. The molecular mechanism regulating miR-429 expression, involving four abnormal hypomethylated sites upstream of the miR-200b/miR-200a/miR-429 cluster, was first defined in both EPCAM+ liver T-ICs and very early-stage HCC tissues. miR-429 secreted by high-expressing cells has the potential to become a proactive signalling molecule to mediate intercellular communication. CONCLUSIONS: Epigenetic modification of miR-429 can manipulate liver T-ICs by targeting the RBBP4/E2F1/OCT4 axis. This miRNA might be targeted to inactivate T-ICs, thus providing a novel strategy for HCC prevention and treatment.

[Combined stress of enhanced UV-B radiation and 1,2,4-trichlorobenzene contamination on the growth of green vegetable].

A pot experiment was conducted to study the effects of UV-B radiation enhancement alone, 1,2,4-trichlorobenzene (TCB) contamination soil alone, and the combined stress on the growing process, stomatal resistance and leaf structure of green vegetable. The results showed that 1,2,4-TCB contamination alone had more significant inhibitory effect on the growth of green vegetable than the combined stress. Both UV-B radiation enhancement and 1,2,4-TCB contamination reduced the stomatal resistance of front and reverse leaves. Enhanced UV-B radiation resulted in the albino of leaves. 1,2,4-TCB contamination resulted in the fading of leaf color and the appearing of black spots on leaf surfaces, and the enhanced UV-B radiation strengthened the black-spot symptom. In conclusion, the effects of UV-B radiation enhancement alone, 1,2,4-trichlorobenzene (TCB) contamination soil alone and the combined stress on the growth indicators of green vegetable were different.