cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.27314377.v1
title: The arginine/ornithine binding protein ArgT plays an essential role in <i>Brucella neotomae</i>/<i>Brucella melitensis</i> to prevent intracellular killing and contribute to chronic persistence in the host

description: <i>Brucella</i> species are facultative intracellular bacterial pathogens that cause the contagious zoonotic disease, brucellosis. <i>Brucella</i> spp. infect a wide range of animals, including livestock, wild animals, and marine mammals. Compared with other invasive bacterial pathogens, partial information is available on the virulence factors of <i>Brucella</i> that enable them to survive in the host. Here, we performed transposon-based random mutagenesis of <i>B. neotomae</i> and identified the arginine/ornithine binding protein, ArgT, as one of the crucial virulence determinants of <i>Brucella</i>. Deleting <i>ArgT</i> from <i>B. neotomae</i> or <i>B. melitensis</i> resulted in its attenuation in macrophages, which was restored upon complementation with an <i>ArgT</i> expression plasmid. We observed that macrophages infected with Δ<i>ArgT-B. neotomae</i> produced elevated levels of NO due to the inability of these mutants to deplete the host intracellular arginine through their importer. Furthermore, defective survival of Δ<i>ArgT B. neotomae</i> and <i>B. melitensis</i> was observed in the infected mice, which correlated with enhanced NO production in the mice. Our studies revealed that <i>ArgT</i> plays a vital role in preventing intracellular killing and contributes to the chronic persistence of <i>B. neotomae/B. melitensis</i> in the host. This study highlights the essential role of arginine in clearing intracellular infections and the subversion of this host defense mechanism by intracellular pathogens for their chronic persistence.
DOI: 10.6084/m9.figshare.25459375.v1
title: <i>Staphylococcus pseudintermedius</i> induces pyroptosis of canine corneal epithelial cells by activating the ROS–NLRP3 signaling pathway

description: <i>Staphylococcus pseudintermedius</i> (<i>S. pseudintermedius</i>) is a common pathogen that causes canine corneal ulcers. However, the pathogenesis remained unclear. In this study, it has been demonstrated that <i>S. pseudintermedius</i> invaded canine corneal epithelial cells (CCECs) intracellularly, mediating oxidative damage and pyroptosis by promoting the accumulation of intracellular reactive oxygen species (ROS) and activating the NLRP3 inflammasome. The canine corneal stroma was infected with <i>S. pseudintermedius</i> to establish the canine corneal ulcer model in vivo. The intracellular infectious model in CCECs was established in vitro to explore the mechanism of the ROS – NLRP3 signalling pathway during the <i>S. pseudintermedius</i> infection by adding NAC or MCC950. Results showed that the expression of NLRP3 and gasdermin D (GSDMD) proteins increased significantly in the infected corneas (<i>p &lt;</i> 0.01). The intracellular infection of <i>S. pseudintermedius</i> was confirmed with transmission electron microscopy and immunofluorescent 3D imaging. Flow cytometry analysis revealed that ROS and pyroptosis rates increased in the experimental group in contrast to the control group (<i>p</i> &lt; 0.01). Furthermore, NAC or MCC950 inhibited activation of the ROS – NLRP3 signalling pathway and pyroptosis rate significantly, by suppressing pro-IL-1β, cleaved- IL-1β, pro-caspase-1, cleaved-caspase-1, NLRP3, GSDMD, GSDMD-N, and HMGB1 proteins. Thus, the research confirmed that oxidative damage and pyroptosis were involved in the process of CCECs infected with <i>S. pseudintermedius</i> intracellularly by the ROS – NLRP3 signalling pathway. The results enrich the understanding of the mechanisms of canine corneal ulcers and facilitate the development of new medicines and prevention measures.
DOI: 10.6084/m9.figshare.27037087
title: Isolation and characterization of a novel S1-gene insertion porcine epidemic diarrhea virus with low pathogenicity in newborn piglets

description: Porcine epidemic diarrhea virus (PEDV) causes diarrhea and vomiting in piglets, leading to a mortality rate of 100%. Due to the high frequency of mutation, it is important to monitor the evolution of PEDV and develop potential vaccine candidates. In this study, two PEDV strains (ZJ2022 and ZQ2022) were identified by PCR. These strains were subsequently isolated, and their genome sequences, growth characteristics, and pathogenicity were compared. Phylogenetic and recombination analyses revealed that both strains belonged to GIIa-subgroup, and ZQ2022 was identified as a recombinant strain derived from ZJ2022. Further sequence analysis showed that the ZJ2022 strain had a modified top region of the S1 protein due to a three amino acid insertion (T380_Y380insGGE) in the S1 gene. According to the virus growth curve, ZJ2022 exhibited better cellular adaptation than ZQ2022, with higher viral titers from 8 hpi to 24 hpi. Additionally, ZQ2022 exhibited a high level of pathogenicity, causing severe diarrhea in piglets at 36 hpi and a 100% mortality rate by 96 hpi. In contrast, ZJ2022 showed lower pathogenicity, inducing severe diarrhea in piglets at 60 hpi, with a mortality rate of 60% at 96 hpi and 100% at 120 hpi. In summary, our findings provided evidence of the undergoing mutations in Chinese PEDV strains. Furthermore, the S gene insertion strain ZJ2022 exhibited strong cellular adaptability and low pathogenicity, making it a potential candidate strain for vaccine development.
DOI: 10.6084/m9.figshare.27037087.v1
title: Isolation and characterization of a novel S1-gene insertion porcine epidemic diarrhea virus with low pathogenicity in newborn piglets

description: Porcine epidemic diarrhea virus (PEDV) causes diarrhea and vomiting in piglets, leading to a mortality rate of 100%. Due to the high frequency of mutation, it is important to monitor the evolution of PEDV and develop potential vaccine candidates. In this study, two PEDV strains (ZJ2022 and ZQ2022) were identified by PCR. These strains were subsequently isolated, and their genome sequences, growth characteristics, and pathogenicity were compared. Phylogenetic and recombination analyses revealed that both strains belonged to GIIa-subgroup, and ZQ2022 was identified as a recombinant strain derived from ZJ2022. Further sequence analysis showed that the ZJ2022 strain had a modified top region of the S1 protein due to a three amino acid insertion (T380_Y380insGGE) in the S1 gene. According to the virus growth curve, ZJ2022 exhibited better cellular adaptation than ZQ2022, with higher viral titers from 8 hpi to 24 hpi. Additionally, ZQ2022 exhibited a high level of pathogenicity, causing severe diarrhea in piglets at 36 hpi and a 100% mortality rate by 96 hpi. In contrast, ZJ2022 showed lower pathogenicity, inducing severe diarrhea in piglets at 60 hpi, with a mortality rate of 60% at 96 hpi and 100% at 120 hpi. In summary, our findings provided evidence of the undergoing mutations in Chinese PEDV strains. Furthermore, the S gene insertion strain ZJ2022 exhibited strong cellular adaptability and low pathogenicity, making it a potential candidate strain for vaccine development.
DOI: 10.6084/m9.figshare.27996796
title: Three transporters, including the novel Gai1 permease, drive amino acid uptake in <i>Histoplasma</i> yeasts

description: The dimorphic fungus <i>Histoplasma capsulatum</i>, which almost exclusively resides within host phagocytic cells during infection, must meet its nutritional needs by scavenging molecules from the phagosome environment. The requirement for gluconeogenesis, but not fatty acid catabolism, for intracellular growth, implicates amino acids as a likely intracellular nutrient source. Consequently, we investigated <i>Histoplasma</i> growth on amino acids. Growth assays demonstrated that <i>Histoplasma</i> yeasts readily utilize most amino acids as nitrogen sources but only efficiently catabolize glutamine, glutamate, aspartate, proline, isoleucine, and alanine as carbon sources. An amino acid permease-based conserved domain search identified 28 putative amino acid transporters within the <i>Histoplasma</i> genome. We characterized the substrate specificities of the major <i>Histoplasma</i> amino acid transporters using a <i>Saccharomyces cerevisiae</i> heterologous expression system and found that <i>H. capsulatum</i> Dip5, Gap3, and a newly described permease, Gai1, comprise most of <i>Histoplasma</i>’s amino acid import capacity. <i>Histoplasma</i> yeasts deficient in these three transporters are impaired for growth on free amino acids but proliferate within macrophages and remain fully virulent during infection of mice, indicating that free amino acids are not the principal nutrient source within the phagosome to support <i>Histoplasma</i> proliferation during infection.
DOI: 10.6084/m9.figshare.27996796.v1
title: Three transporters, including the novel Gai1 permease, drive amino acid uptake in <i>Histoplasma</i> yeasts

description: The dimorphic fungus <i>Histoplasma capsulatum</i>, which almost exclusively resides within host phagocytic cells during infection, must meet its nutritional needs by scavenging molecules from the phagosome environment. The requirement for gluconeogenesis, but not fatty acid catabolism, for intracellular growth, implicates amino acids as a likely intracellular nutrient source. Consequently, we investigated <i>Histoplasma</i> growth on amino acids. Growth assays demonstrated that <i>Histoplasma</i> yeasts readily utilize most amino acids as nitrogen sources but only efficiently catabolize glutamine, glutamate, aspartate, proline, isoleucine, and alanine as carbon sources. An amino acid permease-based conserved domain search identified 28 putative amino acid transporters within the <i>Histoplasma</i> genome. We characterized the substrate specificities of the major <i>Histoplasma</i> amino acid transporters using a <i>Saccharomyces cerevisiae</i> heterologous expression system and found that <i>H. capsulatum</i> Dip5, Gap3, and a newly described permease, Gai1, comprise most of <i>Histoplasma</i>’s amino acid import capacity. <i>Histoplasma</i> yeasts deficient in these three transporters are impaired for growth on free amino acids but proliferate within macrophages and remain fully virulent during infection of mice, indicating that free amino acids are not the principal nutrient source within the phagosome to support <i>Histoplasma</i> proliferation during infection.
DOI: 10.6084/m9.figshare.25744097
title: Loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing K1-ST23 hypervirulent <i>Klebsiella pneumoniae</i>

description: This study aimed at revealing the underlying mechanisms of the loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing hypervirulent <i>Klebsiella pneumoniae</i> (hvKp). Here we longitudinally recovered 3 non-carbapenemase-producing K1-ST23 hvKp strains at a one-month interval (KP29105, KP29499 and KP30086) from an elderly male. Antimicrobial susceptibility testing, whole genome sequencing, transcriptomic sequencing, gene cloning, plasmid conjugation, quantitative real-time PCR (qRT-PCR), and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) were conducted. Among the 3 hvKp strains, KP29105 was resistant to the third- and fourth-generation cephalosporins, KP29499 acquired resistance to both ceftazidime-avibactam and carbapenems, while KP30086 restored its susceptibility to ceftazidime-avibactam, imipenem and meropenem but retained low-level resistance to ertapenem. KP29105 and KP29499 carried plasmid-encoded genes <i>bla</i><sub>CTX-M-15</sub> and <i>bla</i><sub>CTX-M-71</sub>, respectively, but KP30086 lost both. Cloning of gene <i>bla</i><sub>CTX-M-71</sub> and conjugation experiment of <i>bla</i><sub>CTX-M-71</sub>-carrying plasmid showed that the transformant and transconjugant were susceptible to ceftazidime-avibactam but had a more than 8-fold increase in MICs. Supplementation with an outer membrane permeabilizer could reduce the MIC of ceftazidime-avibactam by 32 folds, indicating that porins play a key role in ceftazidime-avibactam resistance. The OmpK35 of the 3 isolates was not expressed, and the OmpK36 of KP29499 and KP30086 had a novel amino acid substitution (L359R). SDS-PAGE and qRT-PCR showed that the expression of porin OmpK36 of KP29499 and KP30086 was significantly down-regulated compared with KP29105. In summary, we reported the rare ceftazidime-avibactam resistance in a non-carbapenemase-producing hvKp strain. Resistance plasmid carrying <i>bla</i><sub>CTX-M-71</sub> and mutated OmpK36 had a synergetic effect on the resistance.
DOI: 10.6084/m9.figshare.25744097.v1
title: Loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing K1-ST23 hypervirulent <i>Klebsiella pneumoniae</i>

description: This study aimed at revealing the underlying mechanisms of the loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing hypervirulent <i>Klebsiella pneumoniae</i> (hvKp). Here we longitudinally recovered 3 non-carbapenemase-producing K1-ST23 hvKp strains at a one-month interval (KP29105, KP29499 and KP30086) from an elderly male. Antimicrobial susceptibility testing, whole genome sequencing, transcriptomic sequencing, gene cloning, plasmid conjugation, quantitative real-time PCR (qRT-PCR), and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) were conducted. Among the 3 hvKp strains, KP29105 was resistant to the third- and fourth-generation cephalosporins, KP29499 acquired resistance to both ceftazidime-avibactam and carbapenems, while KP30086 restored its susceptibility to ceftazidime-avibactam, imipenem and meropenem but retained low-level resistance to ertapenem. KP29105 and KP29499 carried plasmid-encoded genes <i>bla</i><sub>CTX-M-15</sub> and <i>bla</i><sub>CTX-M-71</sub>, respectively, but KP30086 lost both. Cloning of gene <i>bla</i><sub>CTX-M-71</sub> and conjugation experiment of <i>bla</i><sub>CTX-M-71</sub>-carrying plasmid showed that the transformant and transconjugant were susceptible to ceftazidime-avibactam but had a more than 8-fold increase in MICs. Supplementation with an outer membrane permeabilizer could reduce the MIC of ceftazidime-avibactam by 32 folds, indicating that porins play a key role in ceftazidime-avibactam resistance. The OmpK35 of the 3 isolates was not expressed, and the OmpK36 of KP29499 and KP30086 had a novel amino acid substitution (L359R). SDS-PAGE and qRT-PCR showed that the expression of porin OmpK36 of KP29499 and KP30086 was significantly down-regulated compared with KP29105. In summary, we reported the rare ceftazidime-avibactam resistance in a non-carbapenemase-producing hvKp strain. Resistance plasmid carrying <i>bla</i><sub>CTX-M-71</sub> and mutated OmpK36 had a synergetic effect on the resistance.
DOI: 10.6084/m9.figshare.27178225
title: The intricate pathogenicity of Group A <i>Streptococcus</i>: A comprehensive update

description: Group A <i>Streptococcus</i> (GAS) is a versatile pathogen that targets human lymphoid, decidual, skin, and soft tissues. Recent advancements have shed light on its airborne transmission, lymphatic spread, and interactions with neuronal systems. GAS promotes severe inflammation through mechanisms involving inflammasomes, IL-1β, and T-cell hyperactivation. Additionally, it secretes factors that directly induce skin necrosis via Gasdermin activation and sustains survival and replication in human blood through sophisticated immune evasion strategies. These include lysis of erythrocytes, using red cell membranes for camouflage, resisting antimicrobial peptides, evading phagocytosis, escaping from neutrophil extracellular traps (NETs), inactivating chemokines, and cleaving targeted antibodies. GAS also employs molecular mimicry to traverse connective tissues undetected and exploits the host’s fibrinolytic system, which contributes to its stealth and potential for causing autoimmune conditions after repeated infections. Secreted toxins disrupt host cell membranes, enhancing intracellular survival and directly activating nociceptor neurons to induce pain. Remarkably, GAS possesses mechanisms for precise genome editing to defend against phages, and its fibrinolytic capabilities have found applications in medicine. Immune responses to GAS are paradoxical: robust responses to its virulence factors correlate with more severe disease, whereas recurrent infections often show diminished immune reactions. This review focuses on the multifaceted virulence of GAS and introduces novel concepts in understanding its pathogenicity.
DOI: 10.6084/m9.figshare.27178225.v2
title: The intricate pathogenicity of Group A <i>Streptococcus</i>: A comprehensive update

description: Group A <i>Streptococcus</i> (GAS) is a versatile pathogen that targets human lymphoid, decidual, skin, and soft tissues. Recent advancements have shed light on its airborne transmission, lymphatic spread, and interactions with neuronal systems. GAS promotes severe inflammation through mechanisms involving inflammasomes, IL-1β, and T-cell hyperactivation. Additionally, it secretes factors that directly induce skin necrosis via Gasdermin activation and sustains survival and replication in human blood through sophisticated immune evasion strategies. These include lysis of erythrocytes, using red cell membranes for camouflage, resisting antimicrobial peptides, evading phagocytosis, escaping from neutrophil extracellular traps (NETs), inactivating chemokines, and cleaving targeted antibodies. GAS also employs molecular mimicry to traverse connective tissues undetected and exploits the host’s fibrinolytic system, which contributes to its stealth and potential for causing autoimmune conditions after repeated infections. Secreted toxins disrupt host cell membranes, enhancing intracellular survival and directly activating nociceptor neurons to induce pain. Remarkably, GAS possesses mechanisms for precise genome editing to defend against phages, and its fibrinolytic capabilities have found applications in medicine. Immune responses to GAS are paradoxical: robust responses to its virulence factors correlate with more severe disease, whereas recurrent infections often show diminished immune reactions. This review focuses on the multifaceted virulence of GAS and introduces novel concepts in understanding its pathogenicity.
DOI: 10.6084/m9.figshare.27036604
title: <i>Streptococcus suis</i> 5’-nucleotidases contribute to adenosine-mediated immune evasion and virulence in a mouse model

description: <i>Streptococcus suis</i> (<i>S. suis</i>) is an important swine bacterial pathogen and causes human infections, leading to a wide range of diseases. However, the role of 5’-nucleotidases in its virulence remains to be fully elucidated. Herein, we identified four cell wall-anchored 5’-nucleotidases (Snts) within <i>S. suis</i>, named SntA, SntB, SntC, and SntD, each displaying similar domains yet exhibiting low sequence homology. The malachite green reagent and HPLC assays demonstrated that these recombinant enzymes are capable of hydrolysing ATP, ADP, and AMP into adenosine (Ado), with the hierarchy of catalytic efficiency being SntC&gt;SntB&gt;SntA&gt;SntD. Moreover, comprehensive enzymatic activity assays illustrated slight variances in substrate specificity, pH tolerance, and metal ion requirements, yet highlighted a conserved substrate-binding pocket, His–Asp catalytic dyad, metal, and phosphate-binding sites across Snts, with the exception of SntA. Through bactericidal assays and murine infection assays involving in site-mutagenesis strains, it was demonstrated that SntB and SntC collaboratively enhance bacterial survivability within whole blood and polymorphonuclear leukocytes (PMNs) <i>via</i> the Ado-A2aR pathway <i>in vitro</i>, and within murine blood and organs <i>in vivo</i>. This suggests a direct correlation between enzymatic activity and enhancement of bacterial survival and virulence. Collectively, <i>S. suis</i> 5’-nucleotidases additively contribute to the generation of adenosine, influencing susceptibility within blood and PMNs, and enhancing survival within blood and organs <i>in vivo</i>. This elucidation of their integral functions in the pathogenic process of <i>S. suis</i> not only enhances our comprehension of bacterial virulence mechanisms, but also illuminates new avenues for therapeutic intervention aimed at curbing <i>S. suis</i> infections.
DOI: 10.6084/m9.figshare.27036604.v1
title: <i>Streptococcus suis</i> 5’-nucleotidases contribute to adenosine-mediated immune evasion and virulence in a mouse model

description: <i>Streptococcus suis</i> (<i>S. suis</i>) is an important swine bacterial pathogen and causes human infections, leading to a wide range of diseases. However, the role of 5’-nucleotidases in its virulence remains to be fully elucidated. Herein, we identified four cell wall-anchored 5’-nucleotidases (Snts) within <i>S. suis</i>, named SntA, SntB, SntC, and SntD, each displaying similar domains yet exhibiting low sequence homology. The malachite green reagent and HPLC assays demonstrated that these recombinant enzymes are capable of hydrolysing ATP, ADP, and AMP into adenosine (Ado), with the hierarchy of catalytic efficiency being SntC&gt;SntB&gt;SntA&gt;SntD. Moreover, comprehensive enzymatic activity assays illustrated slight variances in substrate specificity, pH tolerance, and metal ion requirements, yet highlighted a conserved substrate-binding pocket, His–Asp catalytic dyad, metal, and phosphate-binding sites across Snts, with the exception of SntA. Through bactericidal assays and murine infection assays involving in site-mutagenesis strains, it was demonstrated that SntB and SntC collaboratively enhance bacterial survivability within whole blood and polymorphonuclear leukocytes (PMNs) <i>via</i> the Ado-A2aR pathway <i>in vitro</i>, and within murine blood and organs <i>in vivo</i>. This suggests a direct correlation between enzymatic activity and enhancement of bacterial survival and virulence. Collectively, <i>S. suis</i> 5’-nucleotidases additively contribute to the generation of adenosine, influencing susceptibility within blood and PMNs, and enhancing survival within blood and organs <i>in vivo</i>. This elucidation of their integral functions in the pathogenic process of <i>S. suis</i> not only enhances our comprehension of bacterial virulence mechanisms, but also illuminates new avenues for therapeutic intervention aimed at curbing <i>S. suis</i> infections.