Surface display of the COE antigen of porcine epidemic diarrhoea virus on Bacillus subtilis spores.

Porcine epidemic diarrhoea virus (PEDV) infects pigs of all ages by invading small intestine, causing acute diarrhoea, vomiting, and dehydration with high morbidity and mortality among newborn piglets. However, current PEDV vaccines are not effective to protect the pigs from field epidemic strains because of poor mucosal immune response and strain variation. Therefore, it is indispensable to develop a novel oral vaccine based on epidemic strains. Bacillus subtilis spores are attractive delivery vehicles for oral vaccination on account of the safety, high stability, and low cost. In this study, a chimeric gene CotC-Linker-COE (CLE), comprising of the B. subtilis spore coat gene cotC fused to the core neutralizing epitope CO-26 K equivalent (COE) of the epidemic strain PEDV-AJ1102 spike protein gene, was constructed. Then recombinant B. subtilis displaying the CLE on the spore surface was developed by homologous recombination. Mice were immunized by oral route with B. subtilis 168-CLE, B. subtilis 168, or phosphate-buffered saline (PBS) as control. Results showed that the IgG antibodies and cytokine (IL-4, IFN-γ) levels in the B. subtilis 168-CLE group were significantly higher than the control groups. This study demonstrates that B. subtilis 168-CLE can generate specific systemic immune and mucosal immune responses and is a potential vaccine candidate against PEDV infection.

LRRC8A promotes Glaesserella parasuis cytolethal distending toxin-induced p53-dependent apoptosis in NPTr cells.

Glaesserella parasuis is an early colonizer of the swine upper respiratory tract and can break through the respiratory barrier for further invasion. However, the mechanisms underlying G. parasuis increases epithelial barrier permeability remain unclear. This study demonstrates that G. parasuis cytolethal distending toxin (CDT) induces p53-dependent apoptosis in new-born piglet tracheal (NPTr) cells. Moreover, we report for the first time that leucine-rich repeat-containing protein 8A (LRRC8A), an essential subunit of the volume-regulated anion channel (VRAC), involves in apoptosis of NPTr cells mediated by G. parasuis CDT. Pharmacological inhibition of VRAC with either PPQ-102 or NS3728 largely attenuated CDT-induced apoptosis in NPTr cells. Additionally, experiments with cells knocked down for LRRC8A using small interfering ribonucleic acid (siRNA) or knocked out LRRC8A using CRISPR/Cas9 technology showed a significant reduction in CDT-induced apoptosis. Conversely, re-expression of Sus scrofa LRRC8A in LRRC8A-/- NPTr cells efficiently complemented the CDT-induced apoptosis. In summary, these findings suggest that LRRC8A is pivotal for G. parasuis CDT-induced apoptosis, providing novel insights into the mechanism of apoptosis caused by CDT.

Duplications of Human Longevity-Associated Genes Across Placental Mammals.

Natural selection has shaped a wide range of lifespans across mammals, with a few long-lived species showing negligible signs of ageing. Approaches used to elucidate the genetic mechanisms underlying mammalian longevity usually involve phylogenetic selection tests on candidate genes, detections of convergent amino acid changes in long-lived lineages, analyses of differential gene expression between age cohorts or species, and measurements of age-related epigenetic changes. However, the link between gene duplication and evolution of mammalian longevity has not been widely investigated. Here, we explored the association between gene duplication and mammalian lifespan by analyzing 287 human longevity-associated genes across 37 placental mammals. We estimated that the expansion rate of these genes is eight times higher than their contraction rate across these 37 species. Using phylogenetic approaches, we identified 43 genes whose duplication levels are significantly correlated with longevity quotients (False Discovery Rate (FDR) < 0.05). In particular, the strong correlation observed for four genes (CREBBP, PIK3R1, HELLS, FOXM1) appears to be driven mainly by their high duplication levels in two ageing extremists, the naked mole rat (Heterocephalus glaber) and the greater mouse-eared bat (Myotis myotis). Further sequence and expression analyses suggest that the gene PIK3R1 may have undergone a convergent duplication event, whereby the similar region of its coding sequence was independently duplicated multiple times in both of these long-lived species. Collectively, this study identified several candidate genes whose duplications may underlie the extreme longevity in mammals, and highlighted the potential role of gene duplication in the evolution of mammalian long lifespans.

Glaesserella parasuis QseBC two-component system senses epinephrine and regulates capD expression.

IMPORTANCE: The key bacterial pathogen Glaesserella parasuis, which can cause Glässer's disease, has caused significant financial losses to the swine industry worldwide. Capsular polysaccharide (CPS) is an important virulence factor for bacteria, providing the ability to avoid recognition and killing by the host immune system. Exploring the alteration of CPS synthesis in G. parasuis in response to epinephrine stimulation can lay the groundwork for revealing the pathogenic mechanism of G. parasuis as well as providing ideas for Glässer's disease control.

HtrA is involved in stress response and adhesion in Glaesserella parasuis serovar 5 strain Nagasaki.

Glaesserella parasuis is an important pathogen that causes fibrinous polyserositis, peritonitis and meningitis in pigs, leading to considerable economic losses to the swine industry worldwide. It is well established that the serine protease HtrA is closely associated with bacterial virulence, but the role of HtrA in G. parasuis pathogenesis remains largely unknown. To characterize the function of the htrA gene in G. parasuis, a ΔhtrA mutant was constructed. We found that the ΔhtrA mutant showed significant growth inhibition under heat shock and alkaline stress conditions, indicating HtrA is involved in stress tolerance and survival of G. parasuis. In addition, deletion of htrA gene resulted in decreased adherence to PIEC and PK-15 cells and increased phagocytic resistance to 3D4/2 macrophages, suggesting that htrA is essential for adherence of G. parasuis. Scanning electron microscopy revealed morphological surface changes of the ΔhtrA mutant, and transcription analysis confirmed that a number of adhesion-associated genes are downregulated, which corroborated the aforementioned phenomenon. Furthermore, G. parasuis HtrA induced a potent antibody response in piglets with Glässer's disease. These observations confirmed that the htrA gene is related to the survival and pathogenicity of G. parasuis.

Factors influencing self-management behavior during the "Blanking Period" in patients with atrial fibrillation: A cross-sectional study based on the information-motivation-behavioral skills model.

BACKGROUND: Atrial fibrillation (AF) is becoming increasingly common. Effective self-management during the "Blanking Period" is critical. The Information-Motivation-Behavioral skills (IMB) model can be used to study health behaviors in chronic disease patients, but it has not been studied in AF patients. OBJECTIVE: The goal of this study was to explore the influencing factors and interaction pathways of self-management behavior in AF patients during the "Blanking Period" using the IMB model. METHODS: From June to December 2021, a cross-sectional design was conducted. Patients with AF during the "Blanking Period" (N=220) were recruited. They filled out several quantitative questionnaires, including the Jessa Atrial Fibrillation Knowledge Questionnaire, the Confidence in Atrial Fibrillation Management Scale, the Perceived Social Support Scale, the All Aspects of Health Literacy Scale, and the Self-care Scale for Chronic Atrial Fibrillation Patients. Data were analyzed using correlation analysis, multiple regression analysis, and path analysis. RESULTS: Total score of self-management behavior was (33.83 ± 10.66). AF knowledge (ß = 0.252, P < 0.001), self-management confidence (ß = 0.219, P < 0.001), social support (ß = 0.291, P < 0.001), and health literacy (ß = 0.262, P < 0.001) were all positively correlated with patients' self-management behavior, accounting for 66.50 percent of the total variance. CONCLUSIONS: During the "Blanking Period", the IMB model can be used to predict the factors that influence self-management behavior in AF patients. By using IMB model, interventions targeting patient-specific influencing factors could improve self-management behavior and quality of life in AF patients.

Effect of social support on illness perception in patients with atrial fibrillation during "Blanking Period": Mediating role of sense of mastery.

AIM: To explore whether sense of mastery can mediate the relationship between social support and illness perception in patients with atrial fibrillation (AF) who were at the "Blanking Period." DESIGN: A cross-sectional design. METHODS: 405 patients with AF who were at the "Blanking Period" in the Affiliated Hospital of Qingdao University were recruited; they completed a set of questionnaires, including the Perceived Social Support Scale, the Personal Mastery Scale and the Brief Illness Perception Questionnaire. RESULTS: Social support and sense of mastery were both adversely connected to illness perception. The indirect effect of social support on illness perception through sense of mastery was negative, accounting for 86.04% of the total effect. CONCLUSION: During the "Blanking Period," better social support and sense of mastery contribute to a positive illness perception of AF patients. Social support also can influence patients' illness perception indirectly via the mediator of sense of mastery.

Campylobacter jejuni Cytolethal Distending Toxin Induces GSDME-Dependent Pyroptosis in Colonic Epithelial Cells.

Background: Cytolethal distending toxin (CDT) is a critical virulence factor of Campylobacter jejuni, and it induces cell death and regulates inflammation response in human epithelial cells. Pyroptosis is an inflammatory form of programmed cell death (PCD), but whether it is involved in CDT-mediated cytotoxicity remains elusive. Aims: This study explores the role and mechanism of pyroptosis in CDT-mediated cytotoxicity. Methods: HCT116 and FHC cell lines were treated with CDT. Cell Counting Kit-8 (CCK-8) assay was used to detect cell viability. Western blotting was used to measure the expression of related proteins in the pathway, and cell morphology observation, annexin V/propidium iodide (PI) staining and lactate dehydrogenase (LDH) release assay were performed to evaluate the occurrence of pyroptosis. Result: Our results show that C. jejuni CDT effectively induces pyroptosis in a dose- and time- dependent manner in human colonic epithelial cells owing to its DNase activity. Specific pyroptotic features including large bubbles emerging from plasma membrane and LDH release were observed upon CDT treatment. Moreover, CDT-induced pyroptosis involves the caspase-9/caspase-3 axis, which is followed by gasdermin E (GSDME) cleavage rather than gasdermin D (GSDMD). N-acetyl cysteine (NAC), a reactive oxygen species (ROS) inhibitor, attenuates the activation of caspase-9/3, the cleavage of GSDME and pyroptotic characteristic, therefore demonstrating ROS initiates pyroptotic signaling. Conclusions: We first clarify a molecular mechanism that CDT induces pyroptosis via ROS/caspase-9/caspase-3/GSDME signaling. These findings provide a new insight on understanding of CDT-induced pathogenesis at the molecular level.

Glaesserella parasuis autotransporters EspP1 and EspP2 are novel IgA-specific proteases.

Background: Glaesserella parasuis causes Glässer's disease, which is associated with severe polyarthritis, fibrinous polyserositis and meningitis, and leads to significant economic losses to the swine industry worldwide. IgA is one of the most important humoral immune factors present on mucosal surfaces, and it plays a crucial role in neutralizing and removing pathogens. G. parasuis is able to colonize the mucosal membrane of respiratory tract without being eliminated. Nevertheless, the immune evasion mechanism of G. parasuis in thwarting IgA remains unclear. Aims: The object of this study is to characterize the IgA degradation activity of Mac-1-containing autotransporter EspP1 and EspP2 from G. parasuis. Methods: The swine IgA was purified and incubated with EspP1 and EspP2 respectively. Western blotting was used to detect the cleavage of swine IgA. Generation of EspP1 and EspP2 mutant protein were used to explore the putative active sites of EspPs. LC-MS/MS based N/C-terminal sequencing was performed to measure the cleavage sites in swine IgA. Result: Our results show that G. parasuis EspP1 and EspP2 cleave swine IgA in a dose- and time- dependent manner. G. parasuis lose the IgA protease activity after simultaneously delete espP1 and espP2 indicating that EspP1 and EspP2 are the only two IgA proteases in G. parasuis. The IgA protease activity of EspP1 and EspP2 is affected by the putative active sites which contain Cys47, His172 and Asp194/195. Swine IgA is cleaved within Cα1 and Cα3 domains upon incubation with EspPs. Moreover, EspPs can degrade neither IgG nor IgM while G. parasuis possess the ability to degrade IgM unexpectedly. It suggests that G. parasuis can secrete other proteases to cleave IgM which have never been reported. Conclusion: We report for the first time that both EspP1 and EspP2 are novel IgA-specific proteases and cleave swine IgA within the Cα1 and Cα3 domains. These findings provide a theoretical basis for the EspPs-induced immune evasion.

Identification of Haemophilus parasuis genes uniquely expressed during infection using in vivo-induced antigen technology.

Haemophilus parasuis is the etiological agent of Glässer's disease which is characterized by fibrinous polyserositis, arthritis and meningitis. The pathogenesis of this bacterium remains largely unknown. Genes expressed in vivo may play an important role in the pathogenicity of H. parasuis. The development of in vivo-induced antigen technology (IVIAT) has provided a valuable tool for the identification of in vivo-induced genes during bacterial infection. In this study, IVIAT was applied to identify in vivo-induced antigens of H. parasuis. Pooled swine H. parasuis-positive sera, adsorbed against in vitro-grown cultures of H. parasuis SH0165 and Escherichia coli BL21 (DE3), were used to screen the inducible expression library of genomic proteins from whole genome sequenced H. parsuis SH0165. Finally, 24 unique genes expressed in vivo were successfully identified after secondary and tertiary screening with IVIAT. These genes were implicated in cell surface proteins, metabolism, stress response, regulation, transportation and other processes. Quantitative real-time PCR showed that the mRNA levels of 24 genes were all upregulated in vivo relative to in vitro, with 13 genes were detected significantly upregulated in H. parasuis infected pigs. Several potential virulence-associated genes were found to be uniquely expressed in vivo, including espP, lnt, hutZ, mreC, vtaA, pilB, tex, sunT and aidA. The results indicated that the proteins identified using IVIAT may play important roles in the pathogenesis of H. parasuis infection in vivo.

High areal capacitance of vanadium oxides intercalated Ti3C2 MXene for flexible supercapacitors with high mass loading.

Flexible all-solid-state supercapacitors (ASSSs) have caught the scientific attention to meet the explosive demand for portable and wearable electronic devices. However, it is difficult for flexible electrode materials to obtain a high areal capacitance at a high mass loading, which limits their commercial applications. In this study, vanadium oxide (V2O5) nanoparticles are introduced into Ti3C2 flakes with the aid of cetyltrimethylammonium bromide (CTAB). The intercalation of V2O5 particles in the interlayer of Ti3C2 establishes a hierarchical structure and facilitates the electrolyte penetration. As a result, the prepared CT-Ti3C2@V2O5 composite electrode achieves a high areal capacitance of 2065 mF cm-2 at 3 mA cm-2 and superior active mass loading (15 mg cm-2). Meanwhile, over 93% capacitance is maintained after 6000 cycles at 18 mA cm-2. The ASSS based on CT-Ti3C2@V2O5 delivers a high areal capacitance of 477 mF cm-2 at 1 mV s-1 and exhibits stable performance at different bending states, which reaches to the advanced level for the ASSSs based on MXenes.

Enhanced photoreduction degradation of polybromodiphenyl ethers with Fe3O4-g-C3N4 under visible light irradiation.

As typical persistent organic pollutants, polybrominated diphenyl ethers (PBDEs) have aroused high environmental concern due to their toxicity and recalcitrant degradation. Herein, we report the enhanced photoreduction degradation of polybromodiphenyl ethers with Fe3O4-g-C3N4 under visible light irradiation (>420 nm). A series of high activity photocatalysts Fe3O4-g-C3N4 (named FeOCN-x) have been synthesized by an in situ growth method. The characterization of the prepared FeOCN-x nanocomposites has been examined by SEM, TEM, ultraviolet-visible diffuse reflectance spectroscopy, a vibrating sample magnetometer, X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer-Emmer-Teller surface area analysis. FeOCN-x hybrids all exhibit good magnetic separation properties with the saturation magnetization at 300 K varying from 0.4 to 6.3 emu g-1. Under visible light irradiation, FeOCN-x hybrids show enhanced photocatalytic activity for the debromination of PBDEs compared with g-C3N4. Among all the hybrids, FeOCN-4 with a 4 wt% Fe3O4 content gives the highest reaction rate, which is 6.7 times as high as that in pure g-C3N4. The FeOCN-x nanocomposites not only exhibit good photostability, but could also be easily recovered by magnetism. The results of the kinetic isotope effects (KIE) and the trapping agent experiments show that the rate determining step in the degradation reaction of PBDEs with FeOCN-x is the rate of electron accumulation in the conductive band. A possible photoreductive mechanism has been proposed. This study shows that the easily magnetically separable recycled photocatalyst FeOCN-x, with high visible light activity, could be an excellent candidate for dealing with halogen pollutants.