HSP90AB1 is a host factor that promotes porcine deltacoronavirus replication.

Porcine deltacoronavirus (PDCoV) is an emerging enteropathogenic coronavirus. It causes mortality in neonatal piglets and is of growing concern because of its broad host range, including humans. To date, the mechanism of PDCoV infection remains poorly understood. Here, based on a genome-wide CRISPR screen of PDCoV-infected cells, we found that HSP90AB1 (heat shock protein 90 alpha family class B1) promotes PDCoV infection. Knockdown or KO of HSP90AB1 in LLC-PK cells resulted in a significantly suppressed PDCoV infection. Infected cells treated with HSP90 inhibitors 17-AAG and VER-82576 also showed a significantly suppressed PDCoV infection, although KW-2478, which does not affect the ATPase activity of HSP90AB1, had no effect on PDCoV infection. We found that HSP90AB1 interacts with the N, NS7, and NSP10 proteins of PDCoV. We further evaluated the interaction between N and HSP90AB1 and found that the C-tail domain of the N protein is the HSP90AB1-interacting domain. Further studies showed that HSP90AB1 protects N protein from degradation via the proteasome pathway. In summary, our results reveal a key role for HSP90AB1 in the mechanism of PDCoV infection and contribute to provide new host targets for PDCoV antiviral research.

Sialic acids as attachment factors in mosquitoes mediating Japanese encephalitis virus infection.

The role of Culex mosquitoes in the transmission of Japanese encephalitis virus (JEV) is crucial, yet the mechanisms of JEV infection in these vectors remain unclear. Previous research has indicated that various host factors participate in JEV infection. Herein, we present evidence that mosquito sialic acids enhance JEV infection both in vivo and in vitro. By treating mosquitoes and C6/36 cells with neuraminidase or lectin, the function of sialic acids is effectively blocked, resulting in significant inhibition of JEV infection. Furthermore, knockdown of the sialic acid biosynthesis genes in Culex mosquitoes also leads to a reduction in JEV infection. Moreover, our research revealed that sialic acids play a role in the attachment of JEV to mosquito cells, but not in its internalization. To further explore the mechanisms underlying the promotion of JEV attachment by sialic acids, we conducted immunoprecipitation experiments to confirm the direct binding of sialic acids to the last α-helix in JEV envelope protein domain III. Overall, our study contributes to a molecular comprehension of the interaction between mosquitoes and JEV and offers potential strategies for preventing the dissemination of flavivirus in natural environments.IMPORTANCEIn this study, we aimed to investigate the impact of glycoconjugate sialic acids on mosquito infection with Japanese encephalitis virus (JEV). Our findings demonstrate that sialic acids play a crucial role in enhancing JEV infection by facilitating the attachment of the virus to the cell membrane. Furthermore, our investigation revealed that sialic acids directly bind to the final α-helix in the JEV envelope protein domain III, thereby accelerating virus adsorption. Collectively, our results highlight the significance of mosquito sialic acids in JEV infection within vectors, contributing to a better understanding of the interaction between mosquitoes and JEV.

Insights into antibiotic and heavy metal resistance interactions in Escherichia coli isolated from livestock manure and fertilized soil.

Heavy metal and antibiotic-resistant bacteria from livestock feces are ecological and public health problems. However, the distribution and relationships of antibiotic resistance genes (ARGs), heavy metal resistance genes (HMRGs), and virulence factors (VFs) and their transmission mechanisms remain unclear. Therefore, we investigated the resistance of Escherichia coli, the prevalence of its ARGs, HMRGs, and VFs, and their transmission mechanisms in livestock fresh feces (FF), composted feces (CF), and fertilized soil (FS). In total, 99.54% (n = 221) and 91.44% (n = 203) of E. coli were resistant to at least one antibiotic and one heavy metal, respectively. Additionally, 72.52% (n = 161) were multi-drug resistant (MDR), of which Cu-resistant E. coli accounted for 72.67% (117/161). More than 99.34% (88/89) of E. coli carried multidrug ARGs, VFs, and the Cu resistance genes cueO and cusABCRFS. The Cu resistance genes cueO and cusABCRFS were mainly located on chromosomes, and cueO and cusF were positively associated with HMRGs, ARGs, and VFs. The Cu resistance genes pcoABCDRS were located on the plasmid pLKYL-P02 flanked by ARGs in PF18C from FF group and on chromosomes flanked by HMRGs in SAXZ1-1 from FS group. These results improved our understanding of bacterial multidrug and heavy metal resistance in the environment.

Upregulation of occludin by cytolethal distending toxin facilitates Glaesserella parasuis adhesion to respiratory tract cells.

Virulent Glaesserella parasuis may engender systemic infection characterized by fibrinous polyserositis and pneumonia. G. parasuis causes systemic disease through upper respiratory tract infection, but the mechanism has not been fully characterized. Tight junction (TJ) proteins maintain the integrity and impermeability of the epithelial barriers. In this work, we applied the recombinant cytolethal distending toxin (CDT) holotoxin and cdt-deficient mutants to assess whether CDT interacted with TJ proteins of airway tract cells. Our results indicated that CDT induced the TJ occludin (OCLN) expression in newborn pig tracheal epithelial cells within the first 3 hours of bacterial infection, followed by a significant decrease. Overexpression of OCLN in target cells made them more susceptible to G. parasuis adhesion, whereas ablation of OCLN expression by CRISPR/Cas 9 gene editing technology in target cells decreased their susceptibility to bacterial adhesion. In addition, CDT treatment could upregulate the OCLN levels in the lung tissue of C57/BL6 mice. In summary, highly virulent G. parasuis strain SC1401 stimulated the tight junction expression, resulting in higher bacterial adhesion to respiratory tract cells, and this process is closely related to CDT. Our results may provide novel insights into G. parasuis infection and CDT-mediated pathogenesis.

Effects of environmental disinfection on microbial population and resistance genes: A case study of the microecology within a panda enclosure.

Widespread use of disinfectants raises concerns over their involvement in altering microbial communities and promoting antimicrobial resistance. This study explores the influence of disinfection protocols on microbial populations and resistance genes within an isolated enclosure environment and in the gut of giant pandas (GPs) held within. Samples of panda feces, air conditioning ducts, soil and bamboo were collected before and after disinfection. High-throughput sequencing characterized the microbial flora of GP gut and environmental microbes inside the artificial habitat. Microbial cultures showed that Escherichia coli (34.6%), Enterococcus (15.4%) and other pathogenic bacteria deposited in feces and the enclosure. Isolates exhibit a consistent resistance to disinfectant, with the greatest resistance shown to cyanuric acid, and the lowest to glutaraldehyde-dodecyl dimethyl ammonium bromide (GD-DDAB) and dodecyl dimethyl ammonium bromide (DDAB). The total number of the culturable bacteria in soil and bamboo were significantly diminished after disinfection but increased in the gut. After disinfection, the richness (Chao1 index) of environment samples increased significantly (P < 0.05), while the richness in gut decreased significantly (P < 0.05). Ten genera showed significant change in feces after disinfection. Metagenome sequencing showed that 126 types of virulence genes were present in feces before disinfection and 37 in soil. After disinfection, 110 virulence genes localized in feces and 53 in soil. Eleven virulence genes including ECP and T2SS increased in feces. A total of 182 antibiotic resistance genes (ARGs) subtypes, potentially conferring resistance to 20 classes of drugs, were detected in the soils and feces, with most belonging to efflux pump protein pathways. After disinfection, the number of resistance genes increased both in gut and soil, which suggests disinfection protocols increase the number of resistance pathways. Our study shows that the use of disinfectants helps to shape the microbial community of GPs and their habitat, and increases populations of resistant strain bacteria.

HSP90AB1 Is a Host Factor Required for Transmissible Gastroenteritis Virus Infection.

Transmissible gastroenteritis virus (TGEV) is an important swine enteric coronavirus causing viral diarrhea in pigs of all ages. Currently, the development of antiviral agents targeting host proteins to combat viral infection has received great attention. The heat shock protein 90 (HSP90) is a critical host factor and has important regulatory effects on the infection of various viruses. However, its roles in porcine coronavirus infection remain unclear. In this study, the effect of HSP90 on TGEV infection was evaluated. In addition, the influence of its inhibitor VER-82576 on proinflammatory cytokine (IL-6, IL-12, TNF-α, CXCL10, and CXCL11) production induced by TGEV infection was further analyzed. The results showed that the knockdown of HSP90AB1 and HSP90 inhibitor VER-82576 treatment resulted in a reduction in TGEV M gene mRNA levels, the N protein level, and virus titers in a dose-dependent manner, while the knockdown of HSP90AA1 and KW-2478 treatment had no significant effect on TGEV infection. A time-of-addition assay indicated that the inhibitory effect of VER-82576 on TGEV infection mainly occurred at the early stage of viral replication. Moreover, the TGEV-induced upregulation of proinflammatory cytokine (IL-6, IL-12, TNF-α, CXCL10, and CXCL11) expression was significantly inhibited by VER-82576. In summary, these findings indicated that HSP90AB1 is a host factor enhancing TGEV infection, and the HSP90 inhibitor VER-82576 could reduce TGEV infection and proinflammatory cytokine production, providing a new perspective for TGEV antiviral drug target design.

Characterization of Functional B-Cell Epitopes at the Amino Terminus of Shigella Invasion Plasmid Antigen B (IpaB).

Shigella invasion plasmid antigen B (IpaB) plays an important role in causing shigellosis. While IpaB's protein structure, contribution to disease mechanism, and protective immunity against Shigella infection have been well studied, the significance of individual antigenic domains, especially at the N terminus, has not been systematically characterized. In an attempt to identify IpaB protein functional epitopes and to construct an optimized polyvalent multiepitope fusion antigen (MEFA) immunogen for development of a protein-based cross protective Shigella vaccine, in this study, we in silico identified immunodominant B-cell epitopes from the IpaB N terminus, fused each epitope to carrier protein CsaB (the major subunit of enterotoxigenic Escherichia coli CS4 adhesin) for epitope fusion proteins, immunized mice with each epitope fusion protein, examined IpaB-specific antibody responses, and assessed antibody functional activity against Shigella bacterial invasion. A total of 10 B-cell continuous epitopes were identified from IpaB N terminus, and after being fused to carrier protein CsaB, each epitope induced anti-IpaB IgG responses in the intramuscularly immunized mice. While in vitro antibody invasion inhibition assays demonstrated that antibodies derived from each identified epitope were functional, epitopes 1 (LAKILASTELGDNTIQAA), 2 (HSTSNILIPELKAPKSL), and 4 (QARQQKNLEFSDKI) induced antibodies to inhibit Shigella sonnei and Shigella flexneri invasion at levels similar to those of recombinant IpaB protein, suggesting that these three IpaB epitopes can be used potentially as IpaB-representing antigens to induce protective anti-IpaB antibodies and for construction of an epitope-based polyvalent MEFA protein immunogen for Shigella vaccine development. IMPORTANCE Currently, there are no effective measures for control or prevention of Shigella infection, the most common cause of diarrhea in children 3 to 5 years of age in developing countries. Challenges in developing Shigella vaccines include virulence heterogeneity among species and serotypes. To overcome virulence heterogeneity challenge and to develop a protein-based multivalent Shigella vaccine, we targeted a panel of virulence factors, including invasion plasmid antigens, identified functional antigenic domains or epitopes as representative antigens, and applied the novel epitope- and structure-based vaccinology platform multiepitope fusion antigen (MEFA) to integrate functional antigenic domains or epitopes into a backbone immunogen to produce a polyvalent immunogen for cross protective antibodies. Identification of functional IpaB epitopes from this study enhances our understanding of IpaB immunogenicity and allows us to directly utilize IpaB epitopes for construction of a cross protective polyvalent Shigella immunogen and to accelerate development of a protein-based Shigella vaccine.

Comparative transcriptome analysis reveals that deletion of CheY influences gene expressions of ABC transports and metabolism in Haemophilus parasuis.

Haemophilus (Glaesserella) parasuis is a commensal bacterium that causes Glässer's disease (GD) in swine. As a global transcriptional factor, CheY regulates the expression of hundreds of genes in H. parasuis. In this study, we measured changes in gene expression at the whole transcriptome level using RNAseq. We identified 2058 co-expressed genes, and found 624 differentially expressed genes (q < 0.05) in ΔcheY and SC1401. Several important GO annotations and signaling pathways were identified. RNA-seq results were assembled according to the reference genome, compared with the annotated gene model, and 12 new transcriptional regions were found. Finally, q-PCR results validated the RNA-seq results with 8 randomly selected genes. The present study indicated that CheY is mainly involved in the regulation of ABC transport, oxidative phosphorylation, and ß-Lactam resistance. We draw the regulatory network of CheY, which offers greater insight into the regulatory mechanism of CheY in H.parasuis.

A class â lentogenic newcastle disease virus strain confers effective protection against the prevalent strains.

The traditional vaccine strains, such as LaSota, do not completely prevent the shedding of NDV. An ideal vaccine which could not only prevent the clinical signs, but significantly reduce the shedding of NDV is urgently needed for the eradication of ND. In this study, an NDV isolate APMV-1/Chicken/China (SC)/PT3/2016 (hereafter referred as PT3) was identified as a class Ⅰ NDV and a lentogenic strain. The antigenic relationship between PT3 and 3 other NDV strains, including vaccine strain LaSota and 2 prevalent genotype Ⅶd and Ⅵb strains were analyzed. The protective efficacy of PT3 and LaSota against challenge with genotype Ⅶd and Ⅵb strains were assessed. The antigenic analysis result showed that 4 strains belong to the single serotype and the PT3 antiserum exhibited the highest HI titer against 3 other NDV strains. The results of protective efficacy showed that both of LaSota and PT3 could provide 100% survivability for infected chickens. However, PT3 performed better in inducing higher humoral responses and reducing virus shedding than the LaSota strain. Lentogenic strains from Class I NDV appear to be promising vaccine candidates for the control of ND, and allows for the easy discrimination of field NDV and vaccine strains.

Identification, genotyping, and pathogenicity of Trichosporon spp. Isolated from Giant pandas (Ailuropoda melanoleuca).

BACKGROUND: Trichosporon is the dominant genus of epidermal fungi in giant pandas (Ailuropoda melanoleuca) and causes local and deep infections. To provide the information needed for the diagnosis and treatment of trichosporosis in giant pandas, the sequence of ITS, D1/D2, and IGS1 loci in 29 isolates of Trichosporon spp. which were isolated from the body surface of giant pandas were combination to investigate interspecies identification and genotype. Morphological development was examined via slide culture. Additionally, mice were infected by skin inunction, intraperitoneal injection, and subcutaneous injection for evaluation of pathogenicity. RESULTS: The twenty-nine isolates of Trichosporon spp. were identified as 11 species, and Trichosporon jirovecii and T. asteroides were the commonest species. Four strains of T. laibachii and one strain of T. moniliiforme were found to be of novel genotypes, and T. jirovecii was identified to be genotype 1. T. asteroides had the same genotype which involved in disseminated trichosporosis. The morphological development processes of the Trichosporon spp. were clearly different, especially in the processes of single-spore development. Pathogenicity studies showed that 7 species damaged the liver and skin in mice, and their pathogenicity was stronger than other 4 species. T. asteroides had the strongest pathogenicity and might provoke invasive infection. The pathological characteristics of liver and skin infections caused by different Trichosporon spp. were similar. CONCLUSIONS: Multiple species of Trichosporon were identified on the skin surface of giant panda, which varied in morphological development and pathogenicity. Combination of ITS, D1/D2, and IGS1 loci analysis, and morphological development process can effectively identify the genotype of Trichosporon spp.

A requirement of TolC1 for effective survival, colonization and pathogenicity of Actinobacillus pleuropneumoniae.

To establish infection in the host, pathogens have evolved sophisticated systems to cope with environmental conditions and to protect cells against host immunity. TolC is the outer membrane channel component of type 1 secretion systems and multidrug efflux pumps that plays critical roles during the infection process in many pathogens. However, little is known about the exact roles of TolC1 in the pathogenicity of A. pleuropneumoniae, an etiological agent of the porcine contagious pleuropneumoniae that causes severe respiratory disease. In this study, deletion of tolC1 causes apparent ultrastructural defects in A. pleuropneumoniae cell examined by transmission electron microscopy. The tolC1 mutant is hypersensitivity to oxidative, osmotic and acid challenges by in vitro stress assays. Analysis on secreted proteins shows that the excretion of ApxIIA and an ApxIVA-like protein, ApxIVA-S, is abolished in the absence of TolC1. This result confirms the essential role of TolC1 in the secretion of Apx toxins and this is the first identification of an ApxIVA-like protein in in vitro culture of A. pleuropneumoniae. Besides, disruption of TolC1 leads to a significant attenuation of virulence in mice by an intraperitoneal route of A. pleuropneumoniae. The basis for the attenuation is further investigated using a mouse intranasal infection model, which reveals an impaired ability to colonize and induce lesions in the lungs for the loss of TolC1 of A. pleuropneumoniae. In conclusion, our findings demonstrate significant roles of TolC1 in facilitating bacterial survival in hostile conditions, maximum colonization as well as pathogenicity during the infection of A. pleuropneumoniae.

Construction of targeted and integrative promoter-reporter plasmids pDK-K and pDK-G to measure gene expression activity in Haemophilus parasuis.

Haemophilus parasuis (H. parasuis) is rather difficult to manipulate genetically due to the diversity of restriction-modification systems and other mechanisms harbored by various isolates. This prevents exogenous plasmids from replicating in this species and hinders research efforts focused on transcriptional regulators in this bacterium. In this study, we generated a convenient promoter reporter system based on gene knock-in method using natural transformation in H. parasuis. Gene knock-in has proven useful as a powerful tool facilitating identification and studying the transcription activities of regulators under a variety of conditions that favor gene transcription or expression from an incorporated promoter. The vectors, pDK-K and pDK-G, carrying promoterless reporter lacZ gene and two homologous sequences flanking a knock-in site, may have some advantages over the extensively used plasmid-bearing reporter system in other bacteria in stability and ease of genetic manipulation in H. parasuis. The knock-in site was positioned at a site occupied by flanking genes that were both hypothetical and had the same transcription orientation, thus the expression of the reversely cloned promoter-lacZ fusion wouldn't be affected by the upstream promoter on the chromosome. The expression activity of lacZ gene under the transcriptional activation of a 300 bp promoter-proximal segment of cyaA, crp or comA genes in H. parasuis was separately validated using X-gal and o-nitrophenyl-ß-d-galactoside(ONPG) as substrates. The derivatives harboring promoter-lacZ fusion segments showed significantly higher ß-galactosidase activity levels than the promoterlessones both in TSB++ broth and on TSA++ plate as screened either by X-gal method or the standard Miller method. We also used pDK vector to further certify that the cyaA promoter is inducible and whose transcriptional levels were in correlation with the growth kinetics of the bacteria in TSB++. With this system, gene knock-in method based on natural transformation in H. parasuis proved to be useful in identifying transcriptional regulation of a certain promoter.

Hsp40 Protein DNAJB6 Interacts with Viral NS3 and Inhibits the Replication of the Japanese Encephalitis Virus.

The Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus prevalent in east and southeast Asia, the Western Pacific, and northern Australia. Since viruses are obligatory intracellular pathogens, the dynamic processes of viral entry, replication, and assembly are dependent on numerous host-pathogen interactions. Efforts to identify JEV-interacting host factors are ongoing because their identification and characterization remain incomplete. Three enzymatic activities of flavivirus non-structural protein 3 (NS3), including serine protease, RNA helicase, and triphosphatase, play major roles in the flaviviruses lifecycle. To identify cellular factors that interact with NS3, we screened a human brain cDNA library using a yeast two-hybrid assay, and identified eight proteins that putatively interact with NS3: COPS5, FBLN5, PPP2CB, CRBN, DNAJB6, UBE2N, ZNF350, and GPR137B. We demonstrated that the DnaJ heat shock protein family (Hsp40) member B6 (DNAJB6) colocalizes and interacts with NS3, and has a negative regulatory function in JEV replication. We also show that loss of DNAJB6 function results in significantly increased viral replication, but does not affect viral binding or internalization. Moreover, the time-course of DNAJB6 disruption during JEV infection varies in a viral load-dependent manner, suggesting that JEV targets this host chaperone protein for viral benefit. Deciphering the modes of NS3-interacting host proteins functions in virion production will shed light on JEV pathogenic mechanisms and may also reveal new avenues for antiviral therapeutics.

Mutation of I176R in the E coding region weakens Japanese encephalitis virus neurovirulence, but not its growth rate in BHK-21 cells.

Previously, we isolated the Japanese encephalitis virus (JEV) strain SCYA201201. In this study, we passed the SCYA201201 strain in Syrian baby hamster kidney (BHK-21) cells 120 times to obtain the SCYA201201-0901 strain, which exhibited an attenuated phenotype in mice. Comparison of SCYA201201-0901 amino acid sequences with those of other JEV strains revealed a single mutation, I176R, in the E coding region. Using reverse genetic technology, we provide evidence that this single E-I176R mutation does not affect virus growth in BHK-21 cells but significantly decreases JEV neurovirulence in mice. This study provides critical information for understanding the molecular mechanism of JEV attenuation.

Genomic changes in an attenuated genotype I Japanese encephalitis virus and comparison with virulent parental strain.

Genotype I Japanese encephalitis virus (JEV) strain SCYA201201 was previously isolated from brain tissues of aborted piglets. In this study, we obtained an attenuated SCYA201201-0901 strain by serial passage of strain SCYA201201-1 in Syrian baby hamster kidney cells, combined with multiple plaque purifications and selection for virulence in mice. We investigated the genetic changes associated with attenuation by comparing the entire genomes of SCYA201201-0901 and SCYA201201-1. Sequence comparisons identified 14 common amino acid substitutions in the coding region, with two nucleotide point mutations in the 5'-untranslated region (UTR) and another three in the 3'-UTR, which differed between the attenuated and virulent strains. In addition, a total of 13 silent nucleotide mutations were found after attenuation. These substitutions, alone or in combination, may be responsible for the attenuated phenotype of the SCYA201201-0901 strain in mice. This information will contribute to our understanding of attenuation and of the molecular basis of virulence in genotype I strains such as SCYA201201-0901, as well as aiding the development of safer JEV vaccines.

Polyamine-binding protein PotD2 is required for stress tolerance and virulence in Actinobacillus pleuropneumoniae.

Actinobacillus pleuropneumoniae is the cause of porcine contagious pleuropneumonia, which is one of the most important respiratory diseases in swine and causes huge economic losses in the swine industry. PotD, a polyamine-binding protein, has been well characterised in many pathogens of humans and animals. In this study, a ΔpotD2 mutant of A. pleuropneumoniae strain MS71 (serovar 1) was constructed successfully by homologous recombination. Growth curves of different strains showed that the growth of the ΔpotD2 mutant was affected greatly in the logarithmic phase compared with that of parental strain. In vitro stress assays revealed that the viability of ΔpotD2 mutant strain was significantly impaired under multiple environmental stresses, including high temperature, oxidation and hyperosmosis. Additionally, the ΔpotD2 mutant caused significantly decreased mortality in a mouse model. Taken together, the findings in this study suggest an important role of PotD2 in the growth, stress tolerance and virulence of A. pleuropneumoniae.

Degradation of 3-phenoxybenzoic acid by a filamentous fungus Aspergillus oryzae M-4 strain with self-protection transformation.

A novel filamentous fungus M-4 strain was isolated from soy sauce koji and identified as Aspergillus oryzae (Collection number: CGMCC 11645) on the basis of morphological characteristics and internal transcribed spacer sequence. M-4 could degrade 80.62 % of 3-phenoxybenzoic acid (3-PBA; 100 mg L-1) within 5 days. 3-PBA degradation occurred in accordance with first-order kinetics. The degradation metabolites of 3-PBA were identified through high-performance liquid chromatography-mass spectrometry (HPLC-MS). Relevant enzymatic activities and substrate utilization were also investigated, which indicated that M-4 could effectively degrade the intermediates of 3-PBA. Base on analysis of these metabolites, a novel biochemical pathway for the degradation of 3-PBA was proposed. There exists a mutual transformation between 3-phenoxy-benzyl alcohol and 3-PBA, which was firstly reported about the degradation of 3-PBA and may be attributed to self-protection transformation of M-4; subsequently, 3-PBA was gradually transformed into phenol, 3-hydroxy-5-phenoxy benzoic acid, protocatechuic acid and gallic acid. The safety of M-4 was evaluated via an acute toxicity test in vivo. The biodegradation ability of M-4 without toxic effects reveals that this fungus may be likely to be used for eliminating 3-PBA from contaminated environment or fermented foods.

Characterization of a novel ß-cypermethrin-degrading Aspergillus niger YAT strain and the biochemical degradation pathway of ß-cypermethrin.

Aspergillus niger YAT strain was obtained from Chinese brick tea (Collection number: CGMCC 10,568) and identified on the basis of morphological characteristics and internal transcribed spacer (ITS) sequence. The strain could degrade 54.83 % of ß-cypermethrin (ß-CY; 50 mg L(-1)) in 7 days and 100 % of 3-phenoxybenzoic acid (3-PBA; 100 mg L(-1)) in 22 h. The half-lives of ß-CY and 3-PBA range from 3.573 to 11.748 days and from 5.635 to 12.160 h, respectively. The degradation of ß-CY and 3-PBA was further described using first-order kinetic models. The pathway and mechanism of ß-CY degraded by YAT were investigated by analyzing the degraded metabolites through high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Relevant enzymatic activities and substrate utilization were also investigated. ß-CY degradation products were analyzed. Results indicated that YAT strain transformed ß-CY into 3-PBA. 3-PBA was then gradually transformed into permethric acid, protocatechuic acid, 3-hydroxy-5-phenoxy benzoic acid, gallic acid, and phenol gradually. The YAT strain can also effectively degrade these metabolites. The results indicated that YAT strain has potential applications in bioremediation of pyrethroid insecticide (PI)-contaminated environments and fermented food.

Genomic traits of multidrug resistant enterotoxigenic Escherichia coli isolates from diarrheic pigs.

Diarrhea caused by enterotoxigenic Escherichia coli (ETEC) infections poses a significant challenge in global pig farming. To address this issue, the study was conducted to identify and characterize 19 ETEC isolates from fecal samples of diarrheic pigs sourced from large-scale farms in Sichuan Province, China. Whole-genome sequencing and bioinformatic analysis were utilized for identification and characterization. The isolates exhibited substantial resistance to cefotaxime, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, ampicillin, tetracycline, florfenicol, and sulfadiazine, but were highly susceptible to amikacin, imipenem, and cefoxitin. Genetic diversity among the isolates was observed, with serotypes O22:H10, O163orOX21:H4, and O105:H8 being dominant. Further analysis revealed 53 resistance genes and 13 categories of 195 virulence factors. Of concern was the presence of tet(X4) in some isolates, indicating potential public health risks. The ETEC isolates demonstrated the ability to produce either heat-stable enterotoxin (ST) alone or both heat-labile enterotoxin (LT) and ST simultaneously, involving various virulence genes. Notably, STa were linked to human disease. Additionally, the presence of 4 hybrid ETEC/STEC isolates harboring Shiga-like toxin-related virulence factors, namely stx2a, stx2b, and stx2e-ONT-2771, was identified. IncF plasmids carrying multiple antimicrobial resistance genes were prevalent, and a hybrid ETEC/STEC plasmid was detected, highlighting the role of plasmids in hybrid pathotype emergence. These findings emphasized the multidrug resistance and pathogenicity of porcine-origin ETEC strains and the potential risk of epidemics through horizontal transmission of drug resistance, which is crucial for effective control strategies and interventions to mitigate the impact on animal and human health.

The S2 Subunit of Infectious Bronchitis Virus Affects Abl2-Mediated Syncytium Formation.

The S2 subunit serves a crucial role in infectious bronchitis virus (IBV) infection, particularly in facilitating membrane fusion. Using reverse genetic techniques, mutant strains of the S2 locus exhibited substantially different syncytium-forming abilities in chick embryonic kidney cells. To determine the precise formation mechanism of syncytium, we demonstrated the co-ordinated role of Abl2 and its mediated cytoskeletal regulatory pathway within the S2 subunit. Using a combination of fluorescence quantification, RNA silencing, and protein profiling techniques, the functional role of S2 subunits in IBV-infected cells was exhaustively determined. Our findings imply that Abl2 is not the primary cytoskeletal regulator, the viral S2 component is involved in indirect regulation, and the three different viral strains activate various cytoskeletal regulatory pathways through Abl2. CRK, CRKL, ABI1, NCKAP1, and ENAH also play a role in cytoskeleton regulation. Our research provides a point of reference for the development of an intracellular regulatory network for the S2 subunit and a foundation for the rational design of antiviral drug targets against Abl2.