Search

Graphene as a typical conductive filler was previously introduced to enhance the protective performance of zinc-rich coatings (ZRC). However, it is not completely clear the correlation between shielding and cathodic protection performances under the effect of introduced graphene. Herein, the effects of graphene on the shielding performance and cathodic protection were explored, respectively. Results revealed that the introduced graphene tends to promote the corrosion of zinc particles, building chemical shielding effects by converting H2O and O2, etc. and then enhancing the physical shielding performance through the spontaneous formation of corrosion products. The chemical and physical shielding effects cooperatively enhance the shielding performance of zinc-rich topcoat (ZRT), which is conducive to prolonging the cathodic protection life of zinc-rich primer (ZRP). It clarifies the essence of graphene enhancing the protective performance of ZRC clearly, and provides theoretical guidance for improving the protective performance of zinc-rich protective coatings.

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 CDKN1Aand 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.

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.

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 Cregene was driven by the green tissue-specific promoter Zm1rbcSto generate transgenic maize KEY. Meanwhile, a gene cassette containing a Nosterminator (NosT) in front of the Cry1Ab/cgene was driven by the strong promoter ZmUbito generate another transgenic maize LOCK. By crossing KEY and LOCK plants, the expressed Cre recombinase under the control of the Zm1rbcSpromoter from KEY maize accurately removed the NosTof 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/cwere 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 furnacalisand 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.

1-Butyl-3-methylimidazolium chloride (BmimCl), an imidazolium-based ionic liquid, is considered the representative emerging persistent aquatic pollutant, and its environmental toxicity has attracted a growing concern. However, most of the investigations focused on monocultures or a single organism, with little information available on the complex syntrophic consortium that dominates the complex and successional biochemical processes, such as anaerobic digestion. In this study, the effect of BmimCl at environmentally relevant levels on glucose anaerobic digestion was therefore investigated in several laboratory-scale mesophilic anaerobic digesters to provide such support. Experimental results showed that BmimCl at 1–20 mg/L inhibited the methane production rate by 3.50–31.03%, and 20 mg/L BmimCl inhibited butyrate, hydrogen, and acetate biotransformation by 14.29%, 36.36%, and 11.57%, respectively. Toxicological mechanism studies revealed that extracellular polymeric substances (EPSs) adsorbed and accumulated BmimCl through carboxyl, amino, and hydroxyl groups, which destroyed the EPSs’ conformational structure, thereby leading to the inactivation of microbial cells. MiSeq sequencing data indicated that the abundance of Clostridium_sensu_stricto_1, Bacteroides, and Methanothrixdecreased by 6.01%, 7.02%, and 18.45%, respectively, in response to 20 mg/L BmimCl. Molecular ecological network analysis showed that compared with the control, the lower network complexity, fewer keystone taxa, and fewer associations among microbial taxa were found in the BmimCl-present digester, indicating the reduced stability of the microbial community.

ABSTRACTLncRNA have been increasingly shown that plays pivotal roles in the development of various diseases, including renal fibrosis. Nevertheless, the pathological function of Long non-coding RNA KCNQ1OT1 (KCNQ1OT1) in the renal fibrosis remains obscure. Unilateral ureteral obstruction (UUO) was used to induce renal fibrosis. We detected the expression levels of KCNQ1OT1 in the TGF-β1-induced HK-2 cells via RT-qPCR analysis. The functions of KCNQ1OT1 on the progression of renal fibrosis were examined by CCK-8, EdU, dual-luciferase reporter, and immunofluorescence analyses. In the present study, we found that sh-KCNQ1OT1 obviously attenuated UUO-induced renal fibrosis. Moreover, production of extracellular matrix (ECM), including α-SMA and Fibronectin levels, was significantly increased in kidney and HK-2 cells after UUO or TGF-β stimulation. Knockdown of KCNQ1OT1 inhibited cell proliferation and inhibits the α-SMA and Fibronectin expression of TGF-β1-induced HK-2 cells. In addition, bioinformatics analysis and dual-luciferase reporter assay indicated that miR-124-3p was a target gene of KCNQ1OT1. Mechanistically, silencing miR-124-3p abolished the repressive effects of KCNQ1OT1 on TGF-β1-induced HK-2 cells. In conclusion, KCNQ1OT1 knockdown plays an anti-fibrotic effect through promotion of miR-124-3p expression in renal fibrosis, which provides a promising therapeutic target for the treatment of renal fibrosis.

An attractive method for assembling densely substituted pyridine derivatives from 1-methyl-1,3-(ar)enynes and nitriles via a formal [4+2] cycloaddition has been established. The well-balanced affinities of two alkali metal salts enable C(sp3)–H bond activation and excellent chemo- and regioselectivities. Experimental studies revealed that nitrile functions only as a partial nitrogen source for pyridine synthesis, and the addition of a metalated imine intermediate to an intramolecular alkyne is the rate-limiting step.

The expanding use of chitosan in sewage and sludge treatment processes raises concerns about its potential environmental impacts. However, investigations of the impacts of chitosan on sewage sludge anaerobic digestion where chitosan is present at substantial levels are sparse. This study therefore aims to fill this knowledge gap through both long-term and batch tests. The results showed that 4 g/kg total suspended solid (TSS) chitosan had no acute effects on methane production, but chitosan at 8–32 g/kg TSS inhibited methane production by 7.2–30.3%. Mass balance and metabolism of organic analyses indicated that chitosan restrained the transfer of organic substrates from solid phase to liquid phase, macromolecules to micromolecules, and finally to methane. Further exploration revealed that chitosan suppressed the secretion of extracellular polymeric substances of anaerobes by occupying the connection sites of indigenous carbohydrates and increased the mass transfer resistance between anaerobes and substrates, which thereby lowered the metabolic activities of anaerobes. Although chitosan could be partly degraded by anaerobes, it is much more persistent to be degraded compared with indigenous organics in sludge. Microbial community and key enzyme encoding gene analyses further revealed that the inhibition of chitosan to CO2-dependent methanogenesis was much severer than that to acetate-dependent methanogenesis.

Ce- or La-doped Cu/SSZ-13 catalysts were prepared by a hydrothermal method and Cu, Ce or La ions were incorporated through stepwise ion exchange. The catalyst activity was measured for the ammonia selective catalytic reduction reaction. The structure and composition of catalyst were characterized by using X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry solid-state NMR, NH3-TPD techniques, and the active components were examined by XPS and XANES. The results indicate that the Ce and La doping can both completely preserve the SCR activity of Cu/SSZ-13 above 300 °C, but there is also a decrease of activity below 200 °C. On the other hand, Ce doping is beneficial to the formation of framework aluminum, stabilizes molecular sieve framework and Cu active sites of Cu/SSZ-13, thereby improves the catalyst hydrothermal stability. But La doping will decrease the amount of framework aluminum and Cu active sites of Cu/SSZ-13 after hydrothermally aging, even destroy zeolite CHA structure. This is quite harmful to the catalyst hydrothermal stability.

Triclocarban (TCC), as a widely used antimicrobial agent, is accumulated in waste activated sludge at a high level and inhibits the subsequent anaerobic digestion of sludge. This study, for the first time, investigated the effectiveness of microbial electrolysis cell-assisted anaerobic digestion (MEC-AD) in mitigating the inhibition of TCC to methane production. Experimental results showed that 20 mg/L TCC inhibited sludge disintegration, hydrolysis, acidogenesis, and methanogenesis processes and finally reduced methane production from traditional sludge anaerobic digestion by 19.1%. Molecular docking revealed the potential inactivation of binding of TCC to key enzymes in these processes. However, MEC-AD with 0.6 and 0.8 V external voltages achieved much higher methane production and controlled the TCC inhibition to less than 5.8%. TCC in the MEC-AD systems was adsorbed by humic substances and degraded to dichlorocarbanilide, leading to a certain detoxification effect. Methanogenic activities were increased in MEC-AD systems, accompanied by complete VFA consumption. Moreover, the applied voltage promoted cell apoptosis and sludge disintegration to release biodegradable organics. Metagenomic analysis revealed that the applied voltage increased the resistance of electrode biofilms to TCC by enriching functional microorganisms (syntrophic VFA-oxidizing and electroactive bacteria and hydrogenotrophic methanogens), acidification and methanogenesis pathways, multidrug efflux pumps, and SOS response.

Extended-spectrum-β-lactamases (ESBLs)-producing Escherichia coliconferred resistance to most β-lactams, except for carbapenems. To date, the transmission mechanism of blaCTX-M, as the most common ESBLs subtype, in E. colihas received sustained attention around the worldwide, but the research on the pathogenicity of blaCTX-M-bearing E. coliis 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. coliG12 and GZM7 were determined by whole genome sequencing, conjugation and S1-pulsed-field gel electrophoresis. The median lethal dose was analyzed in E. coliG12 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. coliG12 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. coliGZM7 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. coliposes a threat to poultry health and food safety, which contributes to elucidate the concept of “One Health” and deserves particular concern.

Despite recent advances in our understanding of the function of long noncoding RNAs (lncRNAs), their roles and functions in DNA repair pathways remain poorly understood. By screening a panel of uncharacterized lncRNAs to identify those whose transcription is induced by double-strand breaks (DSBs), we identified a novel lncRNA referred to as LRIKthat interacts with Ku, which enhances the ability of the Ku heterodimer to detect the presence of DSBs. Here, we show that depletion of LRIKgenerates significantly enhanced sensitivity to DSB-inducing agents and reduced DSB repair efficiency. In response to DSBs, LRIKenhances the recruitment of repair factors at DSB sites and facilitates ?H2AX signaling. Our results demonstrate that LRIKis necessary for efficient repairing DSBs via nonhomologous end-joining pathway.

A palladium-catalyzed coupling procedure of alkenes with alkynylnitriles has been demonstrated for the synthesis of dichlorides. The reaction is the first example of nitrile-assisted C(sp3)–Cl formation promoted by coordination of a cyano group with an alkylpalladium(II) complex. The construction of a five-membered cycle intermediate successfully inhibits the β-hydride abstraction, resulting in direct C–Cl bond reductive elimination of alkylpalladium(II) chloride.

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.

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. mirabilisisolates 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 β-lactamase resistance genes blaOXA-1, blaCTX-M-1G, blaCTX-M-9Gand colistin resistance gene mcr-1were highly carried in the P. mirabilisisolates. 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. mirabilisisolates, 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. mirabilisstrains in this study. The findings were conducive to insight into the resistance mechanism of chicken P. mirabilisstrains and provide a theoretical basis for the use of antibiotics for the treatment of MDR P. mirabilisinfections in veterinary clinic.

ABSTRACTClinical isolates producing hybrid CTX-M β-lactamases, presumably due to recombination between the blaCTX-M-15and blaCTX-M-14elements, have emerged in recent years. Among the hybrid enzymes, CTX-M-64 and CTX-M-14 display the most significant difference in catalytic activity. This study aims to investigate the mechanisms underlying such differential enzymatic activities in order to provide insight into the structure/function relationship of this class of enzymes. Sequence alignment analysis showed that the major differences between the amino acid composition of CTX-M-64 and CTX-M-14 lie at both the N and C termini of the enzymes. Single or multiple amino acid substitutions introduced into CTX-M-64 and CTX-M-14 were found to produce only minor effects on hydrolytic functions; such a finding is consistent with the notion that the discrepancy between the functional activities of the two enzymes is not the result of only a few amino acid changes but is attributable to interactions between a unique set of amino acid residues in each enzyme. This theory is supported by the results of the thermal stability assay, which confirmed that CTX-M-64 is significantly more stable than CTX-M-14. Our data confirmed that, in addition to the important residues located in the active site, residues distal to the active site also contribute to the catalytic activity of the enzyme through stabilizing its structural integrity.

ABSTRACTA variety of CTX-M-type extended-spectrum β-lactamases (ESBLs), including hybrid ones, have been reported in China that are uncommon elsewhere. To better characterize the substrate profiles and enzymatic mechanisms of these enzymes, we performed comparative kinetic analyses of both parental and hybrid CTX-M enzymes, including CTX-M-15, -132, -123, -64, -14 and -55, that are known to confer variable levels of β-lactam resistance in the host strains. All tested enzymes were susceptible to serine β-lactamase inhibitors, with sulbactam exhibiting the weakest inhibitory effects. CTX-M-55, which differs from CTX-M-15 by one substitution, A77V, displayed enhanced catalytic activity (kcat/Km) against expanded-spectrum cephalosporins (ESCs). CTX-M-55 exhibits higher structure stability, most likely by forming hydrophobic interactions between A77V and various key residues in different helices, thereby stabilizing the core architecture of the helix cluster, and indirectly contributes to a more stable active site conformation, which in turn shows higher catalytic efficiency and is more tolerant to temperature change. Analyses of the hybrids and their parental prototypes showed that evolution from CTX-M-15 to CTX-M-132, CTX-M-123, and CTX-M-64, characterized by gradual enhancement of catalytic activity to ESCs, was attributed to introduction of different substitutions to amino acids distal to the active site of CTX-M-15. Similarly, the increased hydrolytic activities against cephalosporins and sensitivity to β-lactamase inhibitors, clavulanic acid and sulbactam, of CTX-M-64 were partly due to the amino acids that were different from CTX-M-14 and located at both the C and N termini of CTX-M-64. These data indicate that residues distal to the active site of CTX-Ms contributed to their enhanced catalytic activities to ESCs.

ABSTRACTThree hybrid CTX-M β-lactamases, CTX-M-64, CTX-M-123, and CTX-M-132, with N and C termini matching CTX-M-1 group enzymes and centers matching CTX-M-9 group enzymes, have been identified. The hybrid gene sequences suggested recombination between blaCTX-M-15and blaCTX-M-14, the two most common blaCTX-Mvariants worldwide. However, blaCTX-M-64and blaCTX-M-123are found in an ISEcp1-blaCTX-Mtransposition unit with a 45-bp “spacer,” rather than the 48 bp usually associated with blaCTX-M-15, and 112 bp of IncA/C plasmid backbone. This is closer to the context of blaCTX-M-55, which has one nucleotide difference from blaCTX-M-15, on IncI2 plasmid pHN1122-1. Here, we characterized an IncI2 plasmid carrying blaCTX-M-15with a 45-bp spacer (pHNY2-1) by complete sequencing and also sequenced IncI2 plasmids carrying blaCTX-M-64(pHNAH46-1) or blaCTX-M-132(pHNLDH19) and an IncI1 plasmid carrying blaCTX-M-123(pHNAH4-1). pHNY2-1 has the same ISEcp1-blaCTX-M-IncA/C insertion as pHN1122-1, pHNAH46-1, and pHNLDH19, and all four plasmid backbones are almost identical. pHNAH4-1 (IncI1 sequence type 108 [ST108]) carries a transposition unit that includes a 2,720-bp fragment of the IncI2 backbone, suggesting ISEcp1-mediated transfer of blaCTX-M-IncA/C-IncI2 to an IncI1 plasmid. All three hybrid blaCTX-Mgenes may have resulted from recombination between blaCTX-M-14and blaCTX-M-15with a 45-bp spacer on an IncI2 plasmid. Five additional Escherichia coliisolates of different sequence types from different provinces, farms, and/or animals had blaCTX-M-64on a pHNAH46-1-like IncI2 plasmid and 9 had blaCTX-M-123on a pHNAH4-1-like IncI1 ST108 plasmid. Thus, epidemic IncI plasmids may be responsible for the spread of blaCTX-M-64and blaCTX-M-123between different animals and different locations in China.

A palladium-catalyzed coupling reaction of alkynylsulfones with alkenes has been described, which provides an efficient and practical entry to various functionalized dichlorinated vinyl sulfones. This method features excellent regio- and stereoselectivities, good functional group compatibility, as well as mild reaction conditions. Mechanistic studies suggest that the reaction goes through sequential syn-chloropalladation, alkene insertion, and C(sp3)–Cl bond formation processes, and the sulfonyl group is crucial to the stereoselectivity control of the reaction.

ABSTRACTThe chimeric blaCTX-M-123gene was identified in two ceftazidime-resistant Escherichia coliisolates from animals in different Chinese provinces. Like other CTX-M-1/9 group hybrids (CTX-M-64 and CTX-M-132), the ends (amino acids 1 to 135 and 234 to 291) of CTX-M-123 match CTX-M-15 while the central part (122 to 241) matches CTX-M-14. blaCTX-M-123is carried on related, but not identical, ∼90-kb IncI1 plasmids in the two isolates, and one isolate simultaneously carries the group 1 blaCTX-M-55gene on an additional IncI2 plasmid.

ABSTRACTpHN1122-1 carrying blaCTX-M-55, from an Escherichia coliisolate from a dog, was completely sequenced. pHN1122-1 has an IncI2 replicon and typical IncI2-associated genetic modules, including mok/hok-finO-yafA/B, nikABC, and two transfer regions, traand pil, as well as a shufflon. blaCTX-M-55is found within a 3.084-kb ISEcp1transposition unit that includes a fragment of IncA/C plasmid backbone. pHN1122-1 and closely related plasmids were identified in other E. coliisolates from animals in China.

The Richards’ equation is widely used to simulate the saturation distributions in porous medium. Due to the high nonlinear of hydraulic diffusivity, it is usually difficult to obtain the analytical solutions, especially for finite boundaries. In this paper, the Richards equation for horizontal infiltration problem with finite Dirichlet boundaries is solved. The whole infiltrating process is divided into three state: the free infiltrating state, the transition state and the steady one, in which the transition state is considered as the key problem for analytical solving. Based on Boltzmann transformation and series expansion technique, an intermediate variable is introduced and an approximate analytical solution is derived for transition state. In addition, the exact solutions for other states are also given in the appendix. The present solutions can be applied for arbitrary nonlinear hydraulic diffusivity in Richards’ equation. Two examples for power law and exponential law diffusivities are shown to confirm the accuracy of present method.

Here, the mechanisms of colistin heteroresistance (CHR) were assessed in 12 Escherichia coliisolates from swine in China. CHR was investigated by population analysis profile tests. CHR stability was studied by culturing isolates for five overnight incubation periods in colistin-free medium. Subsequently, the mcr-1gene and mutations in PmrAB, PhoPQ, and MgrB were screened in parental isolates and resistant subpopulations. Additionally, the expression levels of phoPQ, its target gene pagP, and its negative regulator gene mgrB, as well as pmrABand its target genes pmrHFIJKLMand pmrC, were determined by real-time relative quantitative PCR.