Upregulation of outer membrane porin gene ompC contributed to enhancement of azithromycin susceptibility in multidrug-resistant Escherichia coli.

The outer membrane (OM) in gram-negative bacteria contains proteins that regulate the passive or active uptake of small molecules for growth and cell function, as well as mediate the emergence of antibiotic resistance. This study aims to explore the potential mechanisms for restoring bacteria to azithromycin susceptibility based on transcriptome analysis of bacterial membrane-related genes. Transcriptome sequencing was performed by treating multidrug-resistant Escherichia coli T28R with azithromycin or in combination with colistin and confirmed by reverse transcription-quantitative PCR (RT-qPCR). Azithromycin enzyme-linked immunosorbent assay (ELISA) test, ompC gene overexpression, and molecular docking were utilized to conduct the confirmatory research of the potential mechanisms. We found that colistin combined with azithromycin led to 48 differentially expressed genes, compared to azithromycin alone, such as downregulation of tolA, eptB, lpxP, and opgE and upregulation of ompC gene. Interestingly, the addition of colistin to azithromycin differentially downregulated the mph(A) gene mediating azithromycin resistance, facilitating the intracellular accumulation of azithromycin. Also, overexpression of the ompC elevated azithromycin susceptibility, and colistin contributed to further suppression of the Mph(A) activity in the presence of azithromycin. These findings suggested that colistin firstly enhanced the permeability of bacterial OM, causing intracellular drug accumulation, and then had a repressive effect on the Mph(A) activity along with azithromycin. Our study provides a novel perspective that the improvement of azithromycin susceptibility is related not only to the downregulation of the mph(A) gene and conformational remodeling of the Mph(A) protein but also the upregulation of the membrane porin gene ompC.IMPORTANCEUsually, active efflux via efflux pumps is an important mechanism of antimicrobial resistance, such as the AcrAB-TolC complex and MdtEF. Also, bacterial porins exhibited a substantial fraction of the total number of outer membrane proteins in Enterobacteriaceae, which are involved in mediating the development of the resistance. We found that the upregulation or overexpression of the ompC gene contributed to the enhancement of resistant bacteria to azithromycin susceptibility, probably due to the augment of drug uptakes caused and the opportunity of Mph(A) function suppressed by azithromycin with colistin. Under the combination of colistin and azithromycin treatment, OmpC exhibited an increased selectivity for cationic molecules and played a key role in the restoral of the antibiotic susceptibility. Investigations on the regulation of porin expression that mediated drug resistance would be important in clinical isolates treated with antibiotics.

Horizontal transfer characterization of ColV plasmids in blaCTX-M-bearing avian Escherichia coli.

Extended-spectrum-ß-lactamases (ESBLs)-producing Escherichia coli conferred resistance to most ß-lactams, except for carbapenems. To date, the transmission mechanism of blaCTX-M, as the most common ESBLs subtype, in E. coli has received sustained attention around the worldwide, but the research on the pathogenicity of blaCTX-M-bearing E. coli is still scarce. The aims of this study were to discern the spread characteristics of ColV (encoding colicin V) plasmids in blaCTX-M-positive E. coli. The multi-drug resistance traits, phylogroups, and ColV plasmid profilings were screened in 76 blaCTX-M-positive E. coli. Thereafter, the genetic profiles of E. coli G12 and GZM7 were determined by whole genome sequencing, conjugation and S1-pulsed-field gel electrophoresis. The median lethal dose was analyzed in E. coli G12 and TG12A, the ColV-plasmid transconjugant of G12. Of all 76 blaCTX-M-bearing E. coli, 67.11% exhibited resistance to at least 2 drugs in addition to ceftiofur, 14.47% carried ColV-positive plasmids, and 53.95% were phylogroup C. Further studies demonstrated that the blaCTX-M-bearing E. coli G12 was assigned to the predominant lineage O78:H4-ST117 of phylogroup G. In addition, its ColV-positive plasmid simultaneously carried multiple resistance genes, and could be independently transferred to confer partial pathogenicity on its host by plasmid mating. E. coli GZM7 was O53:H9-ST23 of phylogroup C, which belonged to another representative lineage of APEC (avian pathogenic E. coli). Its ColV-positive plasmid could complete conjugation with the help of the other coexisting-resistance conjugative plasmid, although it failed to transfer alone. Our findings highlight the flexibly horizontal transfer of ColV plasmids along with multidrug-resistant genes among blaCTX-M-bearing E. coli poses a threat to poultry health and food safety, which contributes to elucidate the concept of "One Health" and deserves particular concern.

Municipal sludge biochar skeletal sodium alginate beads for phosphate removal.

A novel Fe/La decorative biochar filled in sodium alginate beads (SA-KBC-Fe/La) was prepared by a simple sol-gel method and applied to adsorb phosphate (P) efficiently from water in this study. The morphology, structure and chemical component of the hydrogel beads were characterized in detail. And the synthesized bead exhibited easy separation and high P uptake of 46.65 mg/g when the Fe: La was of 1: 2 at 298 K with initial P of 100 mg/L, which was much higher than SA gel bead. The adsorption showed that the optimal pH was 6, and the adsorption was met with pseudo-second-order kinetics and Langmuir isothermal models, indicating a chemical adsorption process. The adsorption capacity remained 82 % after 5 cycles of adsorption. The adsorption mechanism of P was mainly of ligand exchange and electrostatic attraction. Compared with other reported adsorbents, the modification of Fe/La could enhance the mechanical property of SA-KBC-Fe/La beads with increasing active sites. Additionally, the involved biochar could lead to excellent thermal stability and hierarchical porous structure of beads with larger specific surface area (54.22 m2/g). The study could provide new ideas for P removal and strategy for the final disposal of municipal sludge.

A new chemotherapy strategy for advanced hepatocellular carcinoma with exrahepatic metastasis: predictors of long-term survival.

The prognosis of hepatocellular carcinoma (HCC) with extrahepatic metastasis (EHM) is extremely poor. This study aimed to identify prognostic factors for systemic chemotherapy of HCC with EHM. Eighty-five patients who received systemic chemotherapy for HCC with EHM between May 2014 and October 2021 were retrospectively evaluated. Patient demographic data and characteristics of hepatic tumors and EHM were assessed to identify factors that were significantly associated with prognosis. Of the 85 patients, 68 (80.0%) had pulmonary metastasis, 11 (12.9%) had abdominal lymph node metastasis, 7 (8.2%) had abdominal metastasis, and 4 (4.7%) had bone metastasis. The median overall survival (OS) was 17.0 months, and the median progression-free survival (PFS) was 5.1 months. Univariate analysis of OS showed that synchronous EHM-HCC, serum albumin level<35 g/l and number of hepatic tumors>1 were significantly associated with poorer OS. The results of the multivariate analysis indicated that the serum albumin level and number of hepatic tumors were independent prognostic factors. Subgroup analysis of patients with 0, 1, or 2 of these independent prognostic factors showed that the median OS was 24.0 months, 16.2 months and 7.7 months and that the ORR was 38.3%, 22.6% and 0, respectively. Systemic chemotherapy is beneficial for well-selected HCC patients with EHM. The number of hepatic tumors and serum albumin level were independent risk factors for prognosis, and the number of risk factors significantly influenced OS. Therefore, these factors need to be considered before administering systemic chemotherapy for HCC patients with EHM.

Responses of plant immune system and rhizosphere soil microbiome to the elicitor BAR11 in Arabidopsis thaliana.

Microbial elicitors have been shown to boost plant immunity by inducing defense responses to reduce plant disease. However, little is known about the changes in plant microbiome and metabolism in the process of enhancing plant immunity with elicitors. The protein elicitor BAR11, from Saccharothrix yanglingensis Hhs.015, induces defense responses in Arabidopsis thaliana that enhances resistance to pathogens. In this study, bar11 was inserted into Col-0 A. thaliana to obtain BAR11-Trans plant by Agrobacterium-mediated immersion transformation. BAR11-Trans exhibited an elevated defense level against Pseudomonas syringae pv. tomato DC3000 while experiencing a decline in biomass production of above-ground parts. In the process, BAR11-Trans increased the activity of phenylalanine ammonia lyase (PAL) and catalase (CAT), and up-regulated genes related to plant defense pathways. Furthermore, BAR11-Trans decreased root tip reactive oxygen species (ROS) levels while increasing ROS burst in the leaves. Soil transplantation experiments showed that soil planted with BAR11-Trans could enhance the resistance of Col-0 A. thaliana to DC3000. Analysis of A. thaliana rhizosphere soil through 16S rRNA amplified sequencing revealed that BAR11-Trans increased the relative abundance and diversity of the rhizosphere microbial community, leading to the recruitment of more plant probiotics. Additionally, the accumulation of kaempferitrin and robinin in BAR11-Trans influenced the physicochemical properties of rhizosphere soil and the composition of the bacterial community. In summary, BAR11-Trans exhibited heightened defense levels compared to Col-0, leading to increased secretion of secondary metabolites and the recruitment of a greater number of microorganisms to adapt to the environment. These findings offer novel insights for the potential application of elicitors in agricultural disease control.

Anxiety, depression symptoms, and psychological resilience among hospitalized COVID-19 patients in isolation: A study from Wuhan, China.

OBJECTIVE: To investigate the status of anxiety, depression, and psychological resilience among individuals with COVID-19, and their interrelationships to provide a scientific basis for developing psychological intervention strategies for these patients. METHODS: A total of 126 patients with COVID-19 who were admitted to Wuhan Huoshenshan Hospital were recruited in this study. A comprehensive survey was conducted using a general information questionnaire, the Self-Rating Anxiety Scale, the self-rating depression scale, and the Chinese version of the psychological Connor-Davidson resilience scale; a questionnaire-based survey was conducted. RESULTS: Significant differences in anxiety scores were observed among COVID-19 patients with different education levels and the number of immediate family members. The differences in depression scores were noted among patients of different age groups, and marital statuses were also significant. The total psychological resilience score and the scores of all dimensions are negatively correlated with anxiety and depression. Furthermore, the patient's gender, the number of immediate family members, and the psychological resilience dimensions are associated with the severity anxiety of patients. Patient age and psychological resilience are associated with the depression level of patients. CONCLUSION: Patients with COVID-19 exhibit elevated levels of both anxiety and depression. Notably, psychological resilience emerges as a protective factor against the development of anxiety and depression.

CRISPR-Cas9-based functional interrogation of unconventional translatome reveals human cancer dependency on cryptic non-canonical open reading frames.

Emerging evidence suggests that cryptic translation beyond the annotated translatome produces proteins with developmental or physiological functions. However, functions of cryptic non-canonical open reading frames (ORFs) in cancer remain largely unknown. To fill this gap and systematically identify colorectal cancer (CRC) dependency on non-canonical ORFs, we apply an integrative multiomic strategy, combining ribosome profiling and a CRISPR-Cas9 knockout screen with large-scale analysis of molecular and clinical data. Many such ORFs are upregulated in CRC compared to normal tissues and are associated with clinically relevant molecular subtypes. We confirm the in vivo tumor-promoting function of the microprotein SMIMP, encoded by a primate-specific, long noncoding RNA, the expression of which is associated with poor prognosis in CRC, is low in normal tissues and is specifically elevated in CRC and several other cancer types. Mechanistically, SMIMP interacts with the ATPase-forming domains of SMC1A, the core subunit of the cohesin complex, and facilitates SMC1A binding to cis-regulatory elements to promote epigenetic repression of the tumor-suppressive cell cycle regulators encoded by CDKN1A and CDKN2B. Thus, our study reveals a cryptic microprotein as an important component of cohesin-mediated gene regulation and suggests that the 'dark' proteome, encoded by cryptic non-canonical ORFs, may contain potential therapeutic or diagnostic targets.

Deregulation of Ribosome Biogenesis in Nitrite-Oxidizing Bacteria Leads to Nitrite Accumulation.

Nitrite (NO2-) accumulation caused by nitrite-oxidizing bacteria (NOB) inhibition in nitrification is a double-edged sword, i.e., a disaster in aquatic environments but a hope for innovating nitrogen removal technology in wastewater treatment. However, little information is available regarding the molecular mechanism of NOB inhibition at the cellular level. Herein, we investigate the response of NOB inhibition on NO2- accumulation established by a side-stream free ammonia treatment unit in a nitrifying reactor using integrated metagenomics and metaproteomics. Results showed that compared with the baseline, the relative abundance and activity of NOB in the experimental stage decreased by 91.64 and 68.66%, respectively, directly resulting in a NO2- accumulation rate of 88%. Moreover, RNA polymerase, translation factors, and aa-tRNA ligase were significantly downregulated, indicating that protein synthesis in NOB was interfered during NO2- accumulation. Further investigations showed that ribosomal proteins and GTPases, responsible for bindings between either ribosomal proteins and rRNA or ribosome subunits, were remarkably downregulated. This suggests that ribosome biogenesis was severely disrupted, which might be the key reason for the inhibited protein synthesis. Our findings fill a knowledge gap regarding the underlying mechanisms of NO2- accumulation, which would be beneficial for regulating the accumulation of NO2- in aquatic environments and engineered systems.

Green tissue-targeted expression of the Cry1Ab/c gene in transgenic maize using the Cre/loxP system as an alternative strategy against lepidopteran pests.

Genetically modified (GM) proteins in edible tissues of transgenic maize are of intense public concern. We provided a Cre/loxP-based strategy for manipulating the expression of transgenes in green tissues while locking them in nongreen tissues. First, the Cre gene was driven by the green tissue-specific promoter Zm1rbcS to generate transgenic maize KEY. Meanwhile, a gene cassette containing a Nos terminator (NosT) in front of the Cry1Ab/c gene was driven by the strong promoter ZmUbi to generate another transgenic maize LOCK. By crossing KEY and LOCK plants, the expressed Cre recombinase under the control of the Zm1rbcS promoter from KEY maize accurately removed the NosT of LOCK maize. Consequently, the expression of blocked Cry1Ab/c was enabled in specific green tissues in their hybrids. The expression level and concentration of Cry1Ab/c were observed using a strategy with high specific accumulation in green tissues (leaf and stem). Still, only a small or absent amount was observed in root and kernel tissues. Furthermore, we assessed the bioactivity of transgenic maize against 2 common lepidopteran pests, Ostrinia furnacalis and Spodoptera frugiperda, in the laboratory and field. The transgenic plants showed high plant resistance levels against the 2 pests, with mortality rates above 97.2% and damage scales below 2.2 compared with the control group. These findings are significant for exploring novel genetic engineering techniques in GM maize and providing a feasible strategy for transgenes avoiding expression in edible parts. In addition, implementing the Cre/loxP-mediated system could relieve public sentiment toward the biosafety of GM plants.

Stigma and its correlates among patients with Crohn's disease: A cross-sectional study in China.

Objectives: Crohn's disease is an incurable disease characterized by unpredictable intestinal symptoms, which unavoidably affect patients' lives and contribute to feelings of stigma. This study aimed to explore the status and its correlates of stigma among patients with Crohn's disease. Methods: Using a convenience sampling, 146 hospitalized patients with Crohn's disease were recruited in a tertiary hospital in Southern China from October 2020 to March 2021. The participants were assessed by demographic and disease-related questionnaires, the Social Impact Scale (SIS), Inflammatory Bowel Disease-Self-Efficacy Scale (IBD-SES), and Social Support Rating Scale (SSRS). Multivariate linear regression analysis was conducted to explore the influencing factors of stigma among patients with Crohn's disease. Results: The mean SIS score was 58.14 ± 10.74, representing a moderate effect of stigma, and 85.6% (125/146) of the patients experienced moderate to high levels of stigma. The multiple linear regression analysis showed that perceived public awareness of the disease, family income, age, and self-efficacy were the main influencing factors of stigma, which could explain 52% of the total variation of stigma among patients with Crohn's disease. Conclusion: Stigma among patients with Crohn's disease is influenced by perceived public awareness of the disease, family income, age, and self-efficacy. Interventions aimed at improving self-efficacy and public awareness should be considered to alleviate the level of stigma, especially for those aged 40 years or older or low-income patients.

Analysis of Regulatory Mechanism of AcrB and CpxR on Colistin Susceptibility Based on Transcriptome and Metabolome of Salmonella Typhimurium.

With the increasing and inappropriate use of colistin, the emerging colistin-resistant isolates have been frequently reported during the last few decades. Therefore, new potential targets and adjuvants to reverse colistin resistance are urgently needed. Our previous study has confirmed a marked increase of colistin susceptibility (16-fold compared to the wild-type Salmonella strain) of cpxR overexpression strain JSΔacrBΔcpxR::kan/pcpxR (simplified as JSΔΔ/pR). To searching for potential new drug targets, the transcriptome and metabolome analysis were carried out in this study. We found that the more susceptible strain JSΔΔ/pR displayed striking perturbations at both the transcriptomics and metabolomics levels. The virulence-related genes and colistin resistance-related genes (CRRGs) were significantly downregulated in JSΔΔ/pR. There were significant accumulation of citrate, α-ketoglutaric acid, and agmatine sulfate in JSΔΔ/pR, and exogenous supplement of them could synergistically enhance the bactericidal effect of colistin, indicating that these metabolites may serve as potential adjuvants for colistin therapy. Additionally, we also demonstrated that AcrB and CpxR could target the ATP and reactive oxygen species (ROS) generation, but not proton motive force (PMF) production pathway to potentiate antibacterial activity of colistin. Collectively, these findings have revealed several previously unknown mechanisms contributing to increased colistin susceptibility and identified potential targets and adjuvants for potentiating colistin treatment of Salmonella infections. IMPORTANCE Emergence of multidrug-resistant (MDR) Gram-negative (G-) bacteria have led to the reconsideration of colistin as the last-resort therapeutic option for health care-associated infections. Finding new drug targets and strategies against the spread of MDR G- bacteria are global challenges for the life sciences community and public health. In this paper, we demonstrated the more susceptibility strain JSΔΔ/pR displayed striking perturbations at both the transcriptomics and metabolomics levels and revealed several previously unknown regulatory mechanisms of AcrB and CpxR on the colistin susceptibility. Importantly, we found that exogenous supplement of citrate, α-ketoglutaric acid, and agmatine sulfate could synergistically enhance the bactericidal effect of colistin, indicating that these metabolites may serve as potential adjuvants for colistin therapy. These results provide a theoretical basis for finding potential new drug targets and adjuvants.

Prevalence of the optrA gene among Streptococcus suis isolates from diseased pigs and identification of a novel integrative conjugative element ICESsu988S.

Aim of this study was to investigate the prevalence and genetic environment of the oxazolidinone resistance gene optrA in Streptococcus suis (S. suis) isolates from diseased pigs in China. A total of 178 S. suis isolates were screened for the optrA gene by PCR. The phenotypes and genotypes of optrA-positive isolates were investigated by antimicrobial susceptibility testing, core genome Multilocus Sequence Typing (cgMLST), capsular serotypes determination and whole-genome sequencing (WGS). Fifty-one (28.7%) S. suis isolates were positive for optrA. Phylogenetic analysis indicated that the spread of the optrA among S. suis isolates was primarily due to horizontal transfer. Analysis of S. suis serotypes from diseased pigs revealed substantial diversity. The genetic environment of optrA was complex and diverse and could be divided into 12 different types. Interestingly, we identified a novel integrative and conjugative element ICESsu988S, carrying optrA and erm(T) genes. This is to the best of our knowledge the first report of the optrA and erm(T) co-located on an ICE in S. suis. Our results showed a high prevalence of optrA gene in S. suis isolates in China. Further research is needed to evaluate the importance of ICEs, as they horizontally propagate important clinical resistance genes.

Regulation of short-chain fatty acids in the immune system.

A growing body of research suggests that short-chain fatty acids (SCFAs), metabolites produced by intestinal symbiotic bacteria that ferment dietary fibers (DFs), play a crucial role in the health status of symbiotes. SCFAs act on a variety of cell types to regulate important biological processes, including host metabolism, intestinal function, and immune function. SCFAs also affect the function and fate of immune cells. This finding provides a new concept in immune metabolism and a better understanding of the regulatory role of SCFAs in the immune system, which impacts the prevention and treatment of disease. The mechanism by which SCFAs induce or regulate the immune response is becoming increasingly clear. This review summarizes the different mechanisms through which SCFAs act in cells. According to the latest research, the regulatory role of SCFAs in the innate immune system, including in NLRP3 inflammasomes, receptors of TLR family members, neutrophils, macrophages, natural killer cells, eosinophils, basophils and innate lymphocyte subsets, is emphasized. The regulatory role of SCFAs in the adaptive immune system, including in T-cell subsets, B cells, and plasma cells, is also highlighted. In addition, we discuss the role that SCFAs play in regulating allergic airway inflammation, colitis, and osteoporosis by influencing the immune system. These findings provide evidence for determining treatment options based on metabolic regulation.

Revealing an unrecognized role of free ammonia in sulfur transformation during sludge anaerobic treatment.

Free ammonia (FA), the unionized form of ammonium, is presented in anaerobic fermentation of waste activated sludge (WAS) at high levels. However, its potential role in sulfur transformation, especially H2S production, during WAS anaerobic fermentation process was unrecognized previously. This work aims to unveil how FA affects anaerobic sulfur transformation in WAS anaerobic fermentation. It was found that FA significantly inhibited H2S production. With an increase of FA from 0.04 to 159 mg/L, H2S production reduced by 69.9%. FA firstly attacked tyrosine-like proteins and aromatic-like proteins in sludge EPSs, with CO groups being responded first, which decreased the percentage of α-helix/(ß-sheet + random coil) and destroyed hydrogen bonding networks. Cell membrane potential and physiological status analysis showed that FA destroyed membrane integrity and increased the ratio of apoptotic and necrotic cells. These destroyed sludge EPSs structure and caused cell lysis, thus strongly inhibited the activities of hydrolytic microorganisms and sulfate reducing bacteria. Microbial analysis showed that FA reduced the abundance of functional microbes (e.g., Desulfobulbus and Desulfovibrio) and genes (e.g., MPST, CysP, and CysN) involved in organic sulfur hydrolysis and inorganic sulfate reduction. These findings unveil an actually existed but previously overlooked contributor to H2S inhibition in WAS anaerobic fermentation.

Nano-Zero-Valent Zinc-Modified Municipal Sludge Biochar for Phosphorus Removal.

Municipal sludge biochar (MSBC) can be used to absorb phosphorus in water for waste treatment. Nano-zero-valent zinc (nZVZ) was uniformly attached to MSBC to obtain a highly efficient phosphorus-absorbing composite material, nZVZ-MSBC. Characterization by FTIR, XPS, XRD, and BET showed that nZVZ was uniformly dispersed on the surface of the MSBC. Zinc loading was able to greatly improve the adsorption performance of MSBC for phosphorus. Adsorption experiments illustrated that the adsorption process conformed to the Langmuir model, and the maximum adsorption amount was 186.5 mg/g, which is much higher than that for other municipal sludge biochars. The adsorption process reached 80% of the maximum adsorption capacity at 90 min, and this gradually stabilized after 240 min; adsorption equilibrium was reached within 24 h. The optimum pH for adsorption was 5. The main adsorption mechanism was chemical adsorption, but physical adsorption, external diffusion, internal diffusion, and surface adsorption also played roles. The potential for application as an efficient adsorbent of phosphorus from water was confirmed. In addition, a novel strategy for municipal sludge disposal and resource utilization is provided.

Epidemic characteristics of the SXT/R391 integrated conjugative elements in multidrug-resistant Proteus mirabilis isolated from chicken farm.

This study was designed to depict prevalence and antimicrobial resistance characteristics of Proteus mirabilis (P. mirabilis) strains in 4 chicken farms and to probe the transfer mechanism of resistance genes. A total of 187 P. mirabilis isolates were isolated from 4 chicken farms. The susceptibility testing of these isolates to 14 antimicrobials showed that the multidrug resistance (MDR) rate was as high as 100%. The ß-lactamase resistance genes blaOXA-1, blaCTX-M-1G, blaCTX-M-9G and colistin resistance gene mcr-1 were highly carried in the P. mirabilis isolates. An MDR strain W47 was selected for whole genome sequencing (WGS) and conjugation experiment. The results showed that W47 carried 23 resistance genes and 64 virulence genes, and an SXT/R391 integrated conjugative elements (ICEs) named ICEPmiChn5 carrying 17 genes was identified in chromosome. ICEPmiChn5 was able to be excised from the chromosome of W47 forming a circular intermediate, but repeated conjugation experiments were unsuccessful. Among 187 P. mirabilis isolates, 144 (77.01%, 144/187) isolates carried ICEPmiChn5-like ICEs, suggesting that ICEs may be the major vector for the transmission of resistance genes among MDR chicken P. mirabilis strains in this study. The findings were conducive to insight into the resistance mechanism of chicken P. mirabilis strains and provide a theoretical basis for the use of antibiotics for the treatment of MDR P. mirabilis infections in veterinary clinic.

Catalytic Degradation of Ciprofloxacin in Aqueous Solution by Peroxymonosulfate Activated with a Magnetic CuFe2O4@Biochar Composite.

A magnetic copper ferrite and biochar composite (CuFe2O4@BC) catalyst was prepared by an improved sol-gel calcination method and initially used for the removal of antibiotics ciprofloxacin (CIP) by activated peroxymonosulfate (PMS). Using CuFe2O4@BC as the activator, 97.8% CIP removal efficiency could be achieved in 30 min. After a continuous degradation cycle, CuFe2O4@BC catalyst still exhibited great stability and repeatability and could also be quickly recovered by an external magnetic field. Meanwhile, the CuFe2O4@BC/PMS system presented good stability for metal ion leaching, which was far less than the leaching of metal ions in the CuFe2O4/PMS system. Moreover, the effects of various influencing factors, such as initial solution pH, activator loading, PMS dosage, reaction temperature, humic acid (HA), and the inorganic anions were explored. The quenching experiments and the electron paramagnetic resonance (EPR) analysis manifested that hydroxyl radical (•OH), sulfate radical (SO4•-), superoxide radical (O2•-), and singlet oxygen (1O2) were generated in the CuFe2O4@BC/PMS system, while 1O2 and O2•- are mainly involved in the degradation process. The synergistic effect between CuFe2O4 and BC enhanced the structural stability and electrical conductivity of the material, which promoted the bonding between the catalyst and PMS, resulting in the enhanced catalytic activity of CuFe2O4@BC. This indicates that CuFe2O4@BC activating PMS is a promising remediation technique for CIP-contaminated water.

Robust and dynamic underwater adhesives enabled by catechol-functionalized poly(disulfides) network.

Developing molecular approaches to the creation of robust and water-resistant adhesive materials promotes a fundamental understanding of interfacial adhesion mechanisms as well as future applications of biomedical adhesive materials. Here, we present a simple and robust strategy that combines natural thioctic acid and mussel-inspired iron-catechol complexes to enable ultra-strong adhesive materials that can be used underwater and simultaneously exhibit unprecedentedly high adhesion strength on diverse surfaces. Our experimental results show that the robust crosslinking interaction of the iron-catechol complexes, as well as high-density hydrogen bonding, are responsible for the ultra-high interfacial adhesion strength. The embedding effect of the hydrophobic solvent-free network of poly(disulfides) further enhances the water-resistance. The dynamic covalent poly(disulfides) network also makes the resulting materials reconfigurable, thus enabling reusability via repeated heating and cooling. This molecule-engineering strategy offers a general and versatile solution to the design and construction of dynamic supramolecular adhesive materials.

Surfactant enhances anaerobic fermentative hydrogen sulfide production: Changes in sulfur-containing organics structure and microbial community.

The presence of surfactants in waste activated sludge (WAS) system is generally regarded as beneficial to sludge treatment such as enhancing sludge dewatering and improving value-added fermentation products generation. However, in this study, it was firstly found that sodium dodecylbenzene sulfonate (SDBS, a typical surfactant) obviously increased toxic hydrogen sulfide (H2S) gas production from WAS anaerobic fermentation at environmentally relevant concentrations. Experimental results showed that H2S production from WAS significantly increased from 53.24 × 10-3 to 111.25 × 10-3 mg/g volatile suspended solids (VSS) when SDBS level increased from 0 to 30 mg/g total suspended solid (TSS). It was found that SDBS presence destroyed WAS structure and enhanced sulfur containing organics release. SDBS reduced the proportion of α-helix structure, damaged disulfide bridges and protein conformation, and effectively destroyed protein structure. SDBS promoted sulfur containing organics degradation and provided more readily hydrolyzed micro-molecule organics for sulfide production. Microbial analysis showed that SDBS addition enhanced the abundance of functional genes encoding protease, ATP-binding cassette transporters, and amino acids lyase, enhanced the activities and abundance of hydrolytic microbes, thus increased sulfide production from the hydrolysis of sulfur containing organics. Compared with the control, 30 mg/g TSS SDBS increased organic sulfurs hydrolysis and amino acids degradation by 47.1 % and 63.5 %, respectively. Key genes analysis further showed that SDBS addition promoted sulfate transport system and dissimilatory sulfate reduction. SDBS presence also lowered fermentation pH, promoted the chemical equilibrium transformation of sulfide, thus increased H2S gas release.

ICEGpa1804, a novel integrative and conjugative element carrying eight resistance genes, identified in Glaesserella parasuis.

ICEGpa1804 was identified in the genome of a serovar 2, ST279 isolate EHP1804 carrying eight different resistance genes from 200 Glaesserella parasuis strains isolated from swine with lower respiratory tract infection in seven provinces of China. Susceptibility testing for EHP1804 was determined by broth microdilution, and its genetic profile was determined by whole-genome sequencing. The complete ICEGpa1804 was analysed by polymerase chain reaction, conjugation assay and bioinformatics tools. The conjugation assay was performed using EHP1804 as the donor and G. parasuis V43 (rifampicin-resistant) as the recipient. ICEGpa1804 has a size of 71,880 bp and contains 83 genes, including eight resistance genes [tet(B), blaRob-1, aphA1, strA, strB, aac(3)-IId, catA3 and sul2]. The conjugation assay showed that ICEGpa1804 could be transferred to G. parasuis V43 with frequencies of 4.3 × 10-7. To the best of the authors' knowledge, this is the first study to identify a novel integrative and conjugative element (ICE) carrying eight resistance genes and seven insertion sequence (IS) elements from a G. parasuis isolate. Tn6743, a novel transposon carrying six resistance genes, was identified. Moreover, ISGpa1, a novel IS256 family insertion element, is the first characterized example of a G. parasuis insertion element. Multiple mobile genetic elements involved in resistance genes were located in chromosomal ICEGpa1804, which showed that ICEs may serve as a vital platform for the accumulation of resistance genes.