cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.6887051.v1
title: Replacing the 238th aspartic acid with an arginine impaired the oligomerization activity and inflammation-inducing property of pyolysin

description: <i>Trueperella pyogenes</i> (<i>T. pyogenes</i>) is an important opportunistic pathogen. Pyolysin (PLO) importantly contributes to the pathogenicity of <i>T. pyogenes</i>. However, the relationship between the structure and function and the virulence of PLO is not well documented. In the current study, recombinant PLO (rPLO) and three rPLO mutants were prepared. rPLO D238R, a mutant with the 238th aspartic acid replaced with an arginine, showed impairment in oligomerization activity on cholesterol-containing liposome and pore-forming activity on sheep red blood cell membrane. Further study employing the prepared mutants confirmed that the pore-forming activity of PLO is essential for inducing excessive inflammation responses in mice by upregulating the expression levels of IL-1β, TNF-α, and IL-6. By contrast, rPLO P499F, another mutant with impaired cell membrane binding capacity, elicited an inflammation response that was dependent on pathogen-associated molecular pattern (PAMP) activity, given that the mutant significantly upregulated the expression of IL-10 in macrophages and in mice, whereas rPLO did not. Results indicated that domain 1 of the PLO molecule plays an important role in maintaining pore-forming activity. Moreover, the PLO pore-forming activity and not PAMP activity is responsible for the inflammation-inducing effect of PLO. The results of this study provided new information for research field on the structure, function, and virulence of PLO. <b>Abbreviations</b>: <i>T. pyogenes: Trueperella pyogenes</i>; PLO: Pyolysin; rPLO: recombinant PLO; PAMP: pathogen-associated molecular pattern; CDCs: cholesterol-dependent cytolysins; PLY: pneumolysin; NLRP3: NLR family pyrin domain containing protein 3; PRRs: pattern recognition receptors; Asp: aspartic acid; TLR4: Toll-like receptor 4; Arg: arginine; Asn: asparagine; IPTG: Isopropyl-β-d-thiogalactoside; PBS: phosphate-buffered saline; sRBCs: sheep red blood cells; TEM: Transmission electron microscopy; RBCM: red blood cell membrane; SDS-PAGE: sodium dodecyl sulfate–polyacrylamide gel electrophoresis; NC membrane: nitrocellulose membrane; SDS-AGE: dodecyl sulfate agarose gel electrophoresis; MDBK cells: Madin–Darby bovine kidney cells; RPMI-1640 medium: Roswell Park Memorial Institute-1640 medium; FBS: fetal bovine serum; BMDMs: bone marrow-derived macrophages; TNF-α: tumor necrosis factor α; IL-1β: interleukin-1β; IFN-γ: interferon-γ; TGF-β: transforming growth factor-β; ELISA: enzyme-linked immunosorbent assay
DOI: 10.6084/m9.figshare.6886388
title: Persistent Zika virus infection in porcine conceptuses is associated with elevated <i>in utero</i> cortisol levels

description: Persistent Zika virus infection in porcine conceptuses is associated with elevated <i>in utero</i> cortisol levels
DOI: 10.6084/m9.figshare.6886388.v1
title: Persistent Zika virus infection in porcine conceptuses is associated with elevated <i>in utero</i> cortisol levels

description: Persistent Zika virus infection in porcine conceptuses is associated with elevated <i>in utero</i> cortisol levels
DOI: 10.6084/m9.figshare.7492001
title: Disarming <i>Staphylococcus aureus</i> from destroying human cells by simultaneously neutralizing six cytotoxins with two human monoclonal antibodies

description: Pathogenesis of <i>Staphylococcus aureus</i> is increasingly recognized to be driven by powerful toxins. <i>Staphylococcus aureus</i> employs up to six pore-forming toxins to subvert the human host defense and to promote bacterial invasion: alpha-hemolysin that disrupts epithelial and endothelial barriers and five leukocidins that lyse phagocytes involved in bacterial clearance. Previously, we described two human monoclonal antibodies (mAbs), ASN-1 that neutralizes alpha-hemolysin and four leukocidins (LukSF-PV, LukED, HlgAB, HlgCB), and ASN-2 that inactivates the 5<sup>th</sup> leukocidin, LukGH. In this study we tested the individual and combined effects of ASN-1 and ASN-2 in multiple <i>in vitro</i> models employing relevant human target cells. We found that diverse <i>S. aureus</i> isolates with different genetic backgrounds (based on MLST- and <i>spa</i>-typing) and antibiotic sensitivity (both MRSA and MSSA) displayed greatly different cytotoxin expression patterns influenced by the type of growth medium used. Both mAbs were required to fully prevent the lysis of human neutrophils exposed to the mixture of recombinant cytotoxins or native toxins present in the culture supernatants of <i>S.</i> <i>aureus</i> isolates. Flow cytometry confirmed the protective effects of ASN-1 + ASN-2 (known as ASN100) on granulocytes, monocytes, NK-cells and T-lymphocytes. ASN-1 alone preserved the integrity of a 3D-primary culture of human tracheal/bronchial mucociliary epithelial tissue infected with <i>S. aureus</i>. We conclude that simultaneous inhibition of alpha-hemolysin and five leukocidins by ASN100 blocks cytolytic activity of <i>S. aureus</i> towards human target cells <i>in vitro</i>.
DOI: 10.6084/m9.figshare.7492001.v1
title: Disarming <i>Staphylococcus aureus</i> from destroying human cells by simultaneously neutralizing six cytotoxins with two human monoclonal antibodies

description: Pathogenesis of <i>Staphylococcus aureus</i> is increasingly recognized to be driven by powerful toxins. <i>Staphylococcus aureus</i> employs up to six pore-forming toxins to subvert the human host defense and to promote bacterial invasion: alpha-hemolysin that disrupts epithelial and endothelial barriers and five leukocidins that lyse phagocytes involved in bacterial clearance. Previously, we described two human monoclonal antibodies (mAbs), ASN-1 that neutralizes alpha-hemolysin and four leukocidins (LukSF-PV, LukED, HlgAB, HlgCB), and ASN-2 that inactivates the 5<sup>th</sup> leukocidin, LukGH. In this study we tested the individual and combined effects of ASN-1 and ASN-2 in multiple <i>in vitro</i> models employing relevant human target cells. We found that diverse <i>S. aureus</i> isolates with different genetic backgrounds (based on MLST- and <i>spa</i>-typing) and antibiotic sensitivity (both MRSA and MSSA) displayed greatly different cytotoxin expression patterns influenced by the type of growth medium used. Both mAbs were required to fully prevent the lysis of human neutrophils exposed to the mixture of recombinant cytotoxins or native toxins present in the culture supernatants of <i>S.</i> <i>aureus</i> isolates. Flow cytometry confirmed the protective effects of ASN-1 + ASN-2 (known as ASN100) on granulocytes, monocytes, NK-cells and T-lymphocytes. ASN-1 alone preserved the integrity of a 3D-primary culture of human tracheal/bronchial mucociliary epithelial tissue infected with <i>S. aureus</i>. We conclude that simultaneous inhibition of alpha-hemolysin and five leukocidins by ASN100 blocks cytolytic activity of <i>S. aureus</i> towards human target cells <i>in vitro</i>.
DOI: 10.6084/m9.figshare.7491935
title: Understanding <i>Mucor circinelloides</i> pathogenesis by comparative genomics and phenotypical studies

description: The increasing number of infections by species of Mucorales and their high mortality constitute an important concern for public health. This study aims to decipher the genetic basis of <i>Mucor circinelloides</i> pathogenicity, which displays virulence in a strain dependent manner. Assuming that genetic differences between strains may be linked to different pathotypes, we have conducted a study to explore genes responsible for virulence in <i>M. circinelloides</i> by whole genome sequencing of the avirulent strain NRRL3631 and comparison with the virulent strain CBS277.49. This genome analysis revealed 773 truncated, discontiguous and absent genes in the NRRL3631 strain. We also examined phenotypic traits resulting in reduced heat stress tolerance, chitosan content and lower susceptibility to toxic compounds (calcofluor white and sodium dodecyl sulphate) in the virulent strain, suggesting the influence of cell wall on pathogenesis. Based on these results, we focused on studying extracellular protein-coding genes by gene deletion and further pathotype characterization of mutants in murine models of pulmonary and systemic infection. Deletion of gene ID112092, which codes for a hypothetical extracellular protein of unknown function, resulted in significant reduction of virulence. Although pathogenesis is a multifactorial process, these findings highlight the crucial role of surface and secreted proteins in <i>M. circinelloides</i> virulence and should promote further studies of other differential genes.
DOI: 10.6084/m9.figshare.7491935.v2
title: Understanding <i>Mucor circinelloides</i> pathogenesis by comparative genomics and phenotypical studies

description: The increasing number of infections by species of Mucorales and their high mortality constitute an important concern for public health. This study aims to decipher the genetic basis of <i>Mucor circinelloides</i> pathogenicity, which displays virulence in a strain dependent manner. Assuming that genetic differences between strains may be linked to different pathotypes, we have conducted a study to explore genes responsible for virulence in <i>M. circinelloides</i> by whole genome sequencing of the avirulent strain NRRL3631 and comparison with the virulent strain CBS277.49. This genome analysis revealed 773 truncated, discontiguous and absent genes in the NRRL3631 strain. We also examined phenotypic traits resulting in reduced heat stress tolerance, chitosan content and lower susceptibility to toxic compounds (calcofluor white and sodium dodecyl sulphate) in the virulent strain, suggesting the influence of cell wall on pathogenesis. Based on these results, we focused on studying extracellular protein-coding genes by gene deletion and further pathotype characterization of mutants in murine models of pulmonary and systemic infection. Deletion of gene ID112092, which codes for a hypothetical extracellular protein of unknown function, resulted in significant reduction of virulence. Although pathogenesis is a multifactorial process, these findings highlight the crucial role of surface and secreted proteins in <i>M. circinelloides</i> virulence and should promote further studies of other differential genes.
DOI: 10.6084/m9.figshare.7491935.v1
title: Understanding <i>Mucor circinelloides</i> pathogenesis by comparative genomics and phenotypical studies

description: The increasing number of infections by species of Mucorales and their high mortality constitute an important concern for public health. This study aims to decipher the genetic basis of <i>Mucor circinelloides</i> pathogenicity, which displays virulence in a strain dependent manner. Assuming that genetic differences between strains may be linked to different pathotypes, we have conducted a study to explore genes responsible for virulence in <i>M. circinelloides</i> by whole genome sequencing of the avirulent strain NRRL3631 and comparison with the virulent strain CBS277.49. This genome analysis revealed 773 truncated, discontiguous and absent genes in the NRRL3631 strain. We also examined phenotypic traits resulting in reduced heat stress tolerance, chitosan content and lower susceptibility to toxic compounds (calcofluor white and sodium dodecyl sulphate) in the virulent strain, suggesting the influence of cell wall on pathogenesis. Based on these results, we focused on studying extracellular protein-coding genes by gene deletion and further pathotype characterization of mutants in murine models of pulmonary and systemic infection. Deletion of gene ID112092, which codes for a hypothetical extracellular protein of unknown function, resulted in significant reduction of virulence. Although pathogenesis is a multifactorial process, these findings highlight the crucial role of surface and secreted proteins in <i>M. circinelloides</i> virulence and should promote further studies of other differential genes.
DOI: 10.6084/m9.figshare.7007330
title: Genomic analysis of the original Elberg <i>Brucella melitensis</i> Rev.1 vaccine strain reveals insights into virulence attenuation

description: The live attenuated <i>Brucella melitensis</i> Rev.1 Elberg-originated vaccine strain has been widely used to control brucellosis in small ruminants. However, despite extensive research, the molecular mechanisms underlying the attenuation of this strain are still unknown. In the current study, we conducted a comprehensive comparative analysis of the whole-genome sequence of Rev.1 against that of the virulent reference strain, <i>B. melitensis</i> 16M. This analysis revealed five regions of insertion and three regions of deletion within the Rev.1 genome, among which, one large region of insertion, comprising 3,951 bp, was detected in the Rev.1 genome. In addition, we found several missense mutations within important virulence-related genes, which may be used to determine the mechanism underlying virulence attenuation. Collectively, our findings provide new insights into the <i>Brucella</i> virulence mechanisms and, therefore, may serve as a basis for the rational design of new <i>Brucella</i> vaccines.
DOI: 10.6084/m9.figshare.7492058
title: Identification of a novel gene in ROD9 island of <i>Salmonella</i> Enteritidis involved in the alteration of virulence-associated genes expression

description: <i>Salmonella enterica</i> subsp. I serovar Enteritidis (<i>S</i>. Enteritidis), one of the causative agents for non-typhoidal gastrointestinal diseases in humans is an intracellular bacterium and mechanism for its invasion into host cells is critical to cause infection. The virulence of the pathogen is explained by the expression of genes located on its pathogenicity islands, mostly encoded under SPI-1 and SPI-2. However, <i>S</i>. Typhimurium SL1344, despite sharing ∼98% of its genome with <i>S.</i> Enteritidis P125109, lacks few regions of differences (ROD) that are hypothesized to impart virulence potential to <i>S.</i> Enteritidis. In this study, we created different mutants in the ROD9 island of <i>S.</i> Enteritidis, also referred as SPI-19 and identified a novel locus, <i>SEN1005</i>, encoding a hypothetical protein that is involved in its pathogenesis. Δ<i>SEN1005</i> displayed significantly reduced entry into cultured epithelial cells as well as uptake by macrophages and failed to cause acute colitis in C57BL/6 mice at day 3 post-infection (p.i.). Additionally, the global transcriptome analysis revealed a highly repressed SPI-1 and other down-regulated genes responsible for flagellar assembly, chemotaxis and motility in the mutant which correlated with decreased invasion and abated inflammation as compared to the wild-type. Therefore, our findings revealed that Δ<i>SEN1005</i> was attenuated <i>in vitro</i> as well as <i>in vivo</i> and we propose this hypothetical protein to play a role in altering the expression of genes involved in <i>Salmonella</i> virulence.
DOI: 10.6084/m9.figshare.7492058.v1
title: Identification of a novel gene in ROD9 island of <i>Salmonella</i> Enteritidis involved in the alteration of virulence-associated genes expression

description: <i>Salmonella enterica</i> subsp. I serovar Enteritidis (<i>S</i>. Enteritidis), one of the causative agents for non-typhoidal gastrointestinal diseases in humans is an intracellular bacterium and mechanism for its invasion into host cells is critical to cause infection. The virulence of the pathogen is explained by the expression of genes located on its pathogenicity islands, mostly encoded under SPI-1 and SPI-2. However, <i>S</i>. Typhimurium SL1344, despite sharing ∼98% of its genome with <i>S.</i> Enteritidis P125109, lacks few regions of differences (ROD) that are hypothesized to impart virulence potential to <i>S.</i> Enteritidis. In this study, we created different mutants in the ROD9 island of <i>S.</i> Enteritidis, also referred as SPI-19 and identified a novel locus, <i>SEN1005</i>, encoding a hypothetical protein that is involved in its pathogenesis. Δ<i>SEN1005</i> displayed significantly reduced entry into cultured epithelial cells as well as uptake by macrophages and failed to cause acute colitis in C57BL/6 mice at day 3 post-infection (p.i.). Additionally, the global transcriptome analysis revealed a highly repressed SPI-1 and other down-regulated genes responsible for flagellar assembly, chemotaxis and motility in the mutant which correlated with decreased invasion and abated inflammation as compared to the wild-type. Therefore, our findings revealed that Δ<i>SEN1005</i> was attenuated <i>in vitro</i> as well as <i>in vivo</i> and we propose this hypothetical protein to play a role in altering the expression of genes involved in <i>Salmonella</i> virulence.
DOI: 10.6084/m9.figshare.7182062.v2
title: BabA-mediated adherence of pediatric ulcerogenic <i>H. pylori</i> strains to gastric mucins at neutral and acidic pH

description: <i>Helicobacter pylori</i> infection can result in non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), adenocarcinoma, and gastric lymphoma. <i>H. pylori</i> reside within the gastric mucus layer, mainly composed of mucins carrying an array of glycan structures that can serve as bacterial adhesion epitopes. The aim of the present study was to characterize the binding ability, adhesion modes, and growth of <i>H. pylori</i> strains from pediatric patients with NUD and PUD to gastric mucins. Our results showed an increased adhesion capacity of pediatric PUD <i>H. pylori</i> strains to human and rhesus monkey gastric mucins compared to the NUD strains both at neutral and acidic pH, regardless if the mucins were positive for Lewis b (Le<sup>b</sup>), Sialyl-Lewis x (SLe<sup>x</sup>) or LacdiNAc. In addition to <i>babA</i> positive strains being more common among PUD associated strains, <i>H. pylori babA</i> positive strains bound more avidly to gastric mucins than NUD <i>babA</i> positive strains at acidic pH. Binding to Le<sup>b</sup> was higher among <i>babA</i> positive PUD <i>H. pylori</i> strains compared to NUD strains at neutral, but not acidic, pH. PUD derived <i>babA</i>-knockout mutants had attenuated binding to mucins and Le<sup>b</sup> at acidic and neutral pH, and to SLe<sup>x</sup> and DNA at acidic pH. The results highlight the role of BabA-mediated adherence of pediatric ulcerogenic <i>H. pylori</i> strains, and points to a role for BabA in adhesion to charged structures at acidic pH, separate from its specific blood group binding activity.
DOI: 10.6084/m9.figshare.7182062
title: BabA-mediated adherence of pediatric ulcerogenic <i>H. pylori</i> strains to gastric mucins at neutral and acidic pH

description: <i>Helicobacter pylori</i> infection can result in non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), adenocarcinoma, and gastric lymphoma. <i>H. pylori</i> reside within the gastric mucus layer, mainly composed of mucins carrying an array of glycan structures that can serve as bacterial adhesion epitopes. The aim of the present study was to characterize the binding ability, adhesion modes, and growth of <i>H. pylori</i> strains from pediatric patients with NUD and PUD to gastric mucins. Our results showed an increased adhesion capacity of pediatric PUD <i>H. pylori</i> strains to human and rhesus monkey gastric mucins compared to the NUD strains both at neutral and acidic pH, regardless if the mucins were positive for Lewis b (Le<sup>b</sup>), Sialyl-Lewis x (SLe<sup>x</sup>) or LacdiNAc. In addition to <i>babA</i> positive strains being more common among PUD associated strains, <i>H. pylori babA</i> positive strains bound more avidly to gastric mucins than NUD <i>babA</i> positive strains at acidic pH. Binding to Le<sup>b</sup> was higher among <i>babA</i> positive PUD <i>H. pylori</i> strains compared to NUD strains at neutral, but not acidic, pH. PUD derived <i>babA</i>-knockout mutants had attenuated binding to mucins and Le<sup>b</sup> at acidic and neutral pH, and to SLe<sup>x</sup> and DNA at acidic pH. The results highlight the role of BabA-mediated adherence of pediatric ulcerogenic <i>H. pylori</i> strains, and points to a role for BabA in adhesion to charged structures at acidic pH, separate from its specific blood group binding activity.
DOI: 10.6084/m9.figshare.7182062.v1
title: BabA-mediated adherence of pediatric ulcerogenic <i>H. pylori</i> strains to gastric mucins at neutral and acidic pH

description: <i>Helicobacter pylori</i> infection can result in non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), adenocarcinoma, and gastric lymphoma. <i>H. pylori</i> reside within the gastric mucus layer, mainly composed of mucins carrying an array of glycan structures that can serve as bacterial adhesion epitopes. The aim of the present study was to characterize the binding ability, adhesion modes, and growth of <i>H. pylori</i> strains from pediatric patients with NUD and PUD to gastric mucins. Our results showed an increased adhesion capacity of pediatric PUD <i>H. pylori</i> strains to human and rhesus monkey gastric mucins compared to the NUD strains both at neutral and acidic pH, regardless if the mucins were positive for Lewis b (Le<sup>b</sup>), Sialyl-Lewis x (SLe<sup>x</sup>) or LacdiNAc. In addition to <i>babA</i> positive strains being more common among PUD associated strains, <i>H. pylori babA</i> positive strains bound more avidly to gastric mucins than NUD <i>babA</i> positive strains at acidic pH. Binding to Le<sup>b</sup> was higher among <i>babA</i> positive PUD <i>H. pylori</i> strains compared to NUD strains at neutral, but not acidic, pH. PUD derived <i>babA</i>-knockout mutants had attenuated binding to mucins and Le<sup>b</sup> at acidic and neutral pH, and to SLe<sup>x</sup> and DNA at acidic pH. The results highlight the role of BabA-mediated adherence of pediatric ulcerogenic <i>H. pylori</i> strains, and points to a role for BabA in adhesion to charged structures at acidic pH, separate from its specific blood group binding activity.
DOI: 10.6084/m9.figshare.7492016
title: O-specific polysaccharide confers lysozyme resistance to extraintestinal pathogenic <i>Escherichia coli</i>

description: Extraintestinal pathogenic <i>Escherichia coli</i> (ExPEC) is the leading cause of bloodstream and other extraintestinal infections in human and animals. The greatest challenge encountered by ExPEC during an infection is posed by the host defense mechanisms, including lysozyme. ExPEC have developed diverse strategies to overcome this challenge. The aim of this study was to characterize the molecular mechanism of ExPEC resistance to lysozyme. For this, 15,000 transposon mutants of a lysozyme-resistant ExPEC strain NMEC38 were screened; 20 genes were identified as involved in ExPEC resistance to lysozyme—of which five were located in the gene cluster between <i>galF</i> and <i>gnd</i>, and were further confirmed to be involved in O-specific polysaccharide biosynthesis. The O-specific polysaccharide was able to inhibit the hydrolytic activity of lysozyme; it was also required by the complete lipopolysaccharide (LPS)-mediated protection of ExPEC against the bactericidal activity of lysozyme. The O-specific polysaccharide was further shown to be able to directly interact with lysozyme. Furthermore, LPS from ExPEC strains of different O serotypes was also able to inhibit the hydrolytic activity of lysozyme. Because of their cell surface localization and wide distribution in Gram-negative bacteria, O-specific polysaccharides appear to play a long-overlooked role in protecting bacteria against exogenous lysozyme.