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Escherichia coli-induced meningitis remains a life-threatening disease despite recent advances in the field of antibiotics-based therapeutics, necessitating continued research on its pathogenesis. The current study aims to elucidate the mechanism through which hemolysin-coregulated protein 1 (Hcp1) induces the apoptosis of human brain microvascular endothelial cells (HBMEC). Co-immunoprecipitation coupled with mass spectrometric (MS) characterization led to the identification of IQ motif containing GTPase activating protein 1 (IQGAP1) as a downstream target of Hcp1. IQGAP1 was found to be up-regulated by Hcp1 treatment and mediate the stimulation of HBMEC apoptosis. It was shown that Hcp1 could compete against Smurf1 for binding to IQGAP1, thereby rescuing the latter from ubiquitin-dependent degradation. Subsequent study suggested that IQGAP1 could stimulate the MAPK signaling pathway by promoting the phosphorylation of ERK1/2, an effect that was blocked by U0126, an MAPK inhibitor. Furthermore, U0126 also demonstrated therapeutic potential against E. coli meningitis in a mouse model. Taken together, our results suggested the feasibility of targeting the MAPK pathway as a putative therapeutic strategy against bacterial meningitis.

Cemented waste rock-tailing backfill (CWTB), as an artificial false roof in the downward-filling mining method, with its fracture mechanical properties, directly affects the safety of workers. However, few studies have been conducted on CWTB. Therefore, in this study, three-point bending tests and digital image correlation were used to systematically investigate the effects of waste rock aggregate content (10, 20, 30, 40, and 50 %) on the bending mechanical properties (bending strength, post-peak toughness, and fracture toughness) and deformation characteristics (crack extension length and crack opening length) of CWTB. In addition, based on the partition modelling method, a mesoscopic DEM model of CWTB was proposed to reveal the crack extension mechanism and contact force evolution trends of CWTB beams. The results showed that increasing the waste rock aggregate content decreased the flexural strength and increased the post-peak toughness of CWTB. The waste rock aggregate content affected the contact force distribution characteristics and contact force variation was the mesoscopic reason for the evolution of the mechanical properties of CWTB. This study provided important experimental data and simulation basis for the engineering application of CWTB. • The flexural fracture behavior of cemented waste rock tailing backfill (CWTB) was investigated. • The fracture development of CWTB beams with different waste rock aggregate contents was visualized using the DIC technique. • A 3D mesoscopic DEM model for CWTB considering real aggregate shape is proposed. • Contact force and microcrack evolution law of CWTB beams under three-point bending load was revealed using PFC3D. [ABSTRACT FROM AUTHOR]

Partial substitution of chemical fertilizer with organic fertilizer (PSCFOF) can improve soil quality and reduce the overreliance of crop yield on chemical fertilizers. However, the relationship between alterations in crop yield and soil microbial community in response to various substitution ratios is not comprehensively understood. This study aimed to investigate the impact of PSCFOF on soil nutrient supply, enzyme activity, bacterial and fungal community, and crop yield. An 11-year (2009 – 2021) field experiment was carried out in a winter wheat–summer maize double-cropping system with four fertilization regimes (no fertilizer, NF; pure chemical fertilizer, NPK; 30% organic substitution, NPKLM; and 50% organic substitution, NPKHM). Co-occurrence network analysis was applied to examine the importance of ecological clusters and keystone species in controlling microbial activities and crop yields. There were no significant differences in soil nutrient contents and annual crop yield between the NPK and NPKLM treatments. However, the NPKHM treatment resulted in significant reductions in crop yield by 9.49%− 16.78%, despite increasing soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), and available phosphorus (AP) by 9.05%, 7.26%, 11.67%, and 26.62%, respectively. This contrasting effect was primarily attributed to the influence of a specific ecological cluster (module 2), rather than the entire microbial community. Long-term 50% organic substitution would suppress keystone species within module 2, such as Aggregatilinea , Luteimonas , Usitatibacter and Microvirga. These species were specifically correlated with soil carbon enzyme activities, including β-glucosidase, invertase, and dehydrogenase, and contributed significantly and positively to crop yield. Organic substitution at different ratios altered soil nutrient content, enzyme activities and microbial community in different intensities and directions. Long-term 30% organic substitution could preserve soil fertility and microbial community, leading to stable crop yield; whereas 50% organic substitution could inhibit keystone species, reduce extracellular enzyme activity and ultimately lead to a decrease in crop yield. Our results highlight the importance of ecological clusters within soil microbial co-occurrence network in regulating crop yield, presenting a new perspective on the variations in crop yield resulting from varying ratios of organic substitution. [Display omitted] • Organic substitution at different ratios had contrasting effects on crop yield. • Organic substitution mitigated microbial diversity loss from chemical fertilizer. • A specific microbial cluster impacted crop yield rather than the overall community. • High organic substitution reduced keystone species linked to enzyme and crop yield. [ABSTRACT FROM AUTHOR]

Long-term exposure to groundwater contaminated with excessive fluoride (F−) can cause irreversible damage to ecosystems and human health. It is necessary for searching economical and reliable solutions to eliminate excess F− within aquatic environments. Herein, the doping technique was applied to modify the biosynthetic hydroxyapatite, and the maximum defluoridation efficiency (90.37%) was obtained in the La@HAP system. The introduction of Fe and Al species prominently reduced the dosage of La species while ensuring the ideal defluoridation effect. At optimal conditions (preparation parameters: biosynthetic time 12 h, pH 7.0, and dosage of La–Fe and La–Al 2 mM; operation parameters: pH 7.0, dosage 0.3 g L−1, and F− content 3.0 mg L−1), the average defluoridation efficiencies of La–Fe@HAP and La–Al@HAP reached 63.42% and 79.79%, respectively. Kinetic results indicated that the F− adsorption on both bimetallic composite adsorbents was better fitted with the pseudo-second-order model, and a higher initial F− content inhibited the reaction rate. Compared with La–Fe@HAP, La–Al@HAP exhibited lower sensitivity to coexisting anions and humic acid, and higher selectivity to F−. Electrostatic interaction and ligand exchange were the main mechanisms for enhancing the adsorption properties of biosynthetic hydroxyapatite, and F− removal was principally depended on the La species (La > Al > Fe). This study provides inspiration for saving the usage of rare earth metals and designing high-performance and low-cost adsorbents with low pH dependence. [Display omitted] • Biosynthetic hydroxyapatite modified by bimetallic hydroxides was synthesized. • La–Al@HAP consistently outperformed La–Fe@HAP at F− adsorption capacity. • La–Al@HAP was less sensitive to coexisting phosphate and humic acid than La–Fe@HAP. • F− was removed via ion exchange, electrostatic interaction, and ligand exchange. • F− adsorption was principally depended on the La species (La > Al > Fe). [ABSTRACT FROM AUTHOR]

Construct a bacteria-algae symbiotic dynamic sponge bioremediation system to simultaneously remove multiple pollutants under micro-pollution conditions. The average removal efficiencies of NH 4 + -N, PO 4 3- -P, total nitrogen (TN), and Ca 2+ were 98.35, 78.74, 95.64, and 84.92 %, respectively. Comparative studies with Auxenochlorella sp. sponge and bacterial sponge bioremediation system confirmed that NH 4 + -N and TN were mainly removed by bacterial heterotrophic nitrification - aerobic denitrification (HN-AD). PO 4 3- -P was removed by algal assimilation and the generation of Ca 3 (PO 4 ) 2 and Ca 5 (PO 4 ) 3 OH, and Ca 2+ was removed by algal electron transfer formation of precipitates and microbially induced calcium precipitation (MICP) by bacteria. Algae provided an aerobic environment for the bacterial HN-AD process through photosynthesis, while respiration produced CO 2 and adsorbed Ca 2+ to promote the formation of calcium precipitates. Immobilization of Ca 2+ with microalgae via bacterial MICP helped to lift microalgal photoinhibition. The bioremediation system provides theoretical support for research on micropolluted water treatment while increasing phosphorus recovery pathways., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The removal of complex pollutants from oligotrophic water is an important challenge for researchers. In this study, the HCl-modified loofah sponge crosslinked polyethyleneimine loaded with biochar (LS/PEI@biochar) biofilm reactor was adapted to achieve efficient removal of complex pollutants in oligotrophic water. On the 35 d, the average removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH 4 + -N), calcium (Ca 2+ ), and phosphate (PO 4 3- -P) in water was 51, 95, 81, and 77 %, respectively. Additionally, it effectively used a low molecular weight carbon source. Scanning electron microscopy (SEM) results showed that the LS/PEI@biochar biocarrier had superior biofilm suspension performance. Meanwhile, analysis of the biocrystals confirmed Ca 2+ and PO 4 3- removal through the generation of CaCO 3 (calcite and vaterite) and Ca 5 (PO 4 ) 3 OH. This study demonstrated that the system has great efficiency and application prospect in treating oligotrophic water on the laboratory scale, and will be further validated for practical application on large-scale oligotrophic water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An Acinetobacter calcoaceticus strain HM12 capable of heterotrophic nitrification-aerobic denitrification (HN-AD) under nutrient-poor conditions was isolated, with an ammonia nitrogen (NH 4 + -N) removal efficiency of 98.53%. It can also remove heavy metals by microbial induced calcium precipitation (MICP) with a Ca 2+ removal efficiency of 75.91%. Optimal conditions for HN-AD and mineralization of the strain were determined by kinetic analysis (pH = 7, C/N = 2.0, Ca 2+  = 70.0 mg L -1 , NH 4 + -N = 5.0 mg L -1 ). Growth curves and nitrogen balance elucidated nitrogen degradation pathways capable of converting NH 4 + -N to gaseous nitrogen. The analysis of the bioprecipitation showed that Zn 2+ and Cd 2+ were removed by the MICP process through co-precipitation and adsorption (maximum removal efficiencies of 93.39% and 80.70%, respectively), mainly ZnCO 3 , CdCO 3 , ZnHPO 4 , Zn 3 (PO 4 ) 2 and Cd 3 (PO 4 ) 2 . Strain HM12 produces humic and fulvic acids to counteract the toxicity of pollutants, as well as aromatic proteins to increase extracellular polymers (EPS) and promote the biomineralization process. This study provides a experimental evidence for the simultaneous removal of multiple pollutants from nutrient-poor waters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)