Spotlight
Molecular Pathogenesis
- Molecular PathogenesisIdentification of the Chromosomal Region Essential for Serovar-Specific Antigen and Virulence of Serovar 1 and 2 Strains of Erysipelothrix rhusiopathiae
Erysipelothrix rhusiopathiae causes swine erysipelas, an infection characterized by acute septicemia or chronic endocarditis and polyarthritis. Among 17 E. rhusiopathiae serovars, determined based on heat-stable peptidoglycan antigens, serovars 1 and 2 are most commonly associated with the disease;...
- Molecular PathogenesisDelineating the Physiological Roles of the PE and Catalytic Domains of LipY in Lipid Consumption in Mycobacterium-Infected Foamy Macrophages
Within tuberculous granulomas, a subpopulation of Mycobacterium tuberculosis resides inside foamy macrophages (FM) that contain abundant cytoplasmic lipid bodies (LB) filled with triacylglycerol (TAG). Upon fusion of LB with M. tuberculosis-containing phagosomes, TAG is hydrolyzed and reprocessed by...
- Molecular PathogenesisSecreted Phosphatase and Deoxyribonuclease Are Required by Pseudomonas aeruginosa To Defend against Neutrophil Extracellular Traps
Neutrophil extracellular traps (NETs) are produced by neutrophils as an innate immune defense mechanism to trap and kill microbial pathogens. NETs are comprised of ejected chromatin that forms a lattice structure enmeshed with numerous antimicrobial proteins.
- Molecular PathogenesisMethylthioadenosine Suppresses Salmonella Virulence
In order to deploy virulence factors at appropriate times and locations, microbes must rapidly sense and respond to various metabolite signals. Previously, we showed a transient elevation of the methionine-derived metabolite methylthioadenosine (MTA) concentration in serum during systemic Salmonella enterica serovar Typhimurium infection.
- Molecular PathogenesisA Light-Regulated Type I Pilus Contributes to Acinetobacter baumannii Biofilm, Motility, and Virulence Functions
Transcriptional analyses of Acinetobacter baumannii ATCC 17978 showed that the expression of A1S_2091 was enhanced in cells cultured in darkness at 24°C through a process that depended on the BlsA photoreceptor. Disruption of A1S_2091, a component of the A1S_2088-A1S_2091 polycistronic operon predicted to code for a type I chaperone/usher pilus assembly system,...
- Molecular PathogenesisCyclo-(l-Phe-l-Pro), a Quorum-Sensing Signal of Vibrio vulnificus, Induces Expression of Hydroperoxidase through a ToxR-LeuO-HU-RpoS Signaling Pathway To Confer Resistance against Oxidative Stress
Vibrio vulnificus, an opportunistic human pathogen, produces cyclo-(l-Phe-l-Pro) (cFP), which serves as a signaling molecule controlling the ToxR-dependent expression of innate bacterial genes, and also as a virulence factor eliciting pathogenic effects on human cells by enhancing intracellular reactive oxygen species...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
- Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsPlasmodium vivax Merozoite Surface Protein 1 Paralog as a Mediator of Parasite Adherence to Reticulocytes
Plasmodium vivax parasites preferentially invade reticulocytes in human beings. P. vivax merozoite surface protein 1 (PvMSP1) and PvMSP1 paralog (PvMSP1P) may have important functions in reticulocyte adherence during invasion.
- Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsThe Protozoan Parasite Toxoplasma gondii Selectively Reprograms the Host Cell Translatome
The intracellular parasite Toxoplasma gondii promotes infection by targeting multiple host cell processes; however, whether it modulates mRNA translation is currently unknown. Here, we show that infection of primary murine macrophages with type I or II T. gondii strains causes a profound...
- Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsGain-of-Function Analysis Reveals Important Virulence Roles for the Yersinia pestis Type III Secretion System Effectors YopJ, YopT, and YpkA
Virulence of Yersinia pestis in mammals requires the type III secretion system, which delivers seven effector proteins into the cytoplasm of host cells to undermine immune responses. All seven of these effectors are conserved across Y. pestis strains, but three, YopJ, YopT, and YpkA, are apparently...
- Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsGene Regulation by Redox-Sensitive Burkholderia thailandensis OhrR and Its Role in Bacterial Killing of Caenorhabditis elegans
Fatty acid hydroperoxides are involved in host-pathogen interactions. In both plants and mammals, polyunsaturated fatty acids are liberated during infection and enzymatically oxidized to the corresponding toxic hydroperoxides during the defensive oxidative burst that is designed to thwart the infection.
Bacterial Infections
- Bacterial InfectionsShort-Chain Fatty Acids Alter Metabolic and Virulence Attributes of Borrelia burgdorferi
Borrelia burgdorferi responds to a variety of host-derived factors and appropriately alters its gene expression for adaptation under different host-specific conditions. We previously showed that various levels of acetate, a short-chain fatty acid (SCFA), altered the protein profile of B. burgdorferi...
- Bacterial InfectionsEdwardsiella piscicida Type III Secretion System Effector EseK Inhibits Mitogen-Activated Protein Kinase Phosphorylation and Promotes Bacterial Colonization in Zebrafish Larvae
Bacteria utilize type III secretion systems (T3SS) to deliver effectors directly into host cells. Hence, it is very important to identify the functions of bacterial (T3SS) effectors to understand host-pathogen interactions.
- Bacterial Infections | SpotlightMalaria Parasite-Mediated Alteration of Macrophage Function and Increased Iron Availability Predispose to Disseminated Nontyphoidal Salmonella Infection
Disseminated infections with nontyphoidal Salmonella (NTS) are a significant cause of child mortality in sub-Saharan Africa. NTS infection in children is clinically associated with malaria, suggesting that malaria compromises the control of disseminated NTS infection.
- Bacterial Infections | SpotlightUrine Cytokine and Chemokine Levels Predict Urinary Tract Infection Severity Independent of Uropathogen, Urine Bacterial Burden, Host Genetics, and Host Age
Urinary tract infections (UTIs) are among the most common infections worldwide. Diagnosing UTIs in older adults poses a significant challenge as asymptomatic colonization is common.
- Bacterial InfectionsIn Vivo Intradermal Delivery of Bacteria by Using Microneedle Arrays
Infectious diseases propagated by arthropod vectors, such as tularemia, are commonly initiated via dermal infection of the skin. However, due to the technical difficulties in achieving accurate and reproducible dermal deposition, intradermal models are less commonly used.
- Bacterial InfectionsNovel Immunoprotective Proteins of Streptococcus pneumoniae Identified by Opsonophagocytosis Killing Screen
The success of polysaccharide conjugate vaccines represents a major advance in the prevention of pneumococcal disease, but the power of these vaccines is limited by partial spectrum of coverage and high cost. Vaccines using immunoprotective proteins are a promising alternative type of pneumococcal vaccines.
Host Response and Inflammation
- Host Response and InflammationAssociation of Antibodies to VAR2CSA and Merozoite Antigens with Pregnancy Outcomes in Women Living in Yaoundé, Cameroon
Plasmodium falciparum infections are serious in pregnant women, because VAR2CSA allows parasitized erythrocytes to sequester in the placenta, causing placental malaria (PM). In areas of endemicity, women have substantial malarial immunity prior to pregnancy, including antibodies to merozoite antigens, but produce antibodies to VAR2CSA only during pregnancy.
... - Host Response and Inflammation | SpotlightPlatelets Enhance Dendritic Cell Responses against Staphylococcus aureus through CD40-CD40L
Staphylococcus aureus is a major human pathogen that can cause mild to severe life-threatening infections in many tissues and organs. Platelets are known to participate in protection against S. aureus by direct killing and by enhancing the activities of neutrophils and macrophages in clearing...
- Host Response and InflammationInterleukin-17A Exacerbates Disease Severity in BALB/c Mice Susceptible to Lung Infection with Mycoplasma pulmonis
Mycoplasmas are atypical bacteria that disrupt the immune response to promote respiratory tract infections and secondary complications. However, not every immunologic response that protects or damages the host during mycoplasma infection is known.
- Host Response and InflammationReduction of Articular and Systemic Inflammation by Kava-241 in a Porphyromonas gingivalis-Induced Arthritis Murine Model
Rheumatoid arthritis (RA) is an inflammatory disease that has been linked to several risk factors, including periodontitis. Identification of new anti-inflammatory compounds to treat arthritis is needed.
- Host Response and Inflammation | SpotlightCaspase-1 and Caspase-11 Mediate Pyroptosis, Inflammation, and Control of Brucella Joint Infection
Brucellosis, caused by the intracellular bacterial pathogen Brucella, is a zoonotic disease for which arthritis is the most common focal complication in humans. Here we investigated the role of inflammasomes and their effectors, including interleukin-1 (IL-1), IL-18, and pyroptosis, on inflammation and control of infection during...
- Host Response and InflammationRegulation of the Peptidoglycan Amidase PGLYRP2 in Epithelial Cells by Interleukin-36γ
Interleukin-36 (IL-36) cytokines are important regulators of mucosal homeostasis and inflammation. We have previously established that oral epithelial cells upregulate IL-36γ expression in response to the bacterial pathogen Porphyromonas gingivalis.
- Host Response and InflammationSslE (YghJ), a Cell-Associated and Secreted Lipoprotein of Neonatal Septicemic Escherichia coli, Induces Toll-Like Receptor 2-Dependent Macrophage Activation and Proinflammation through NF-κB and MAP Kinase Signaling
SslE (YghJ), a cell surface-associated and secreted lipoprotein, was identified as a potential vaccine candidate for extraintestinal pathogenic Escherichia coli, providing nearly complete protection from sepsis in a mouse model. We earlier found that SslE from neonatal septicemic E. coli could...
- Host Response and InflammationLow Levels of T Cell Exhaustion in Tuberculous Lung Granulomas
The hallmarks of pulmonary Mycobacterium tuberculosis infection are lung granulomas. These organized structures are composed of host immune cells whose purpose is to contain or clear infection, creating a complex hub of immune and bacterial cell activity, as well as limiting pathology in the lungs.
- Host Response and InflammationHigh Mobility Group Protein 1 Reverses Immune System Paralysis in Late-Phase Sepsis
High mobility group protein 1 (HMGB1) is considered to be the primary inflammatory factor triggering immune paralysis in late-phase sepsis. In this study, however, we wanted to explore the possibility of using HMGB1 to boost local differentiation of bone marrow cells (BMCs) into regulatory dendritic cells (DCs) in vivo, thereby inducing immune reversal in late-phase sepsis and improving the prognosis.
Fungal and Parasitic Infections
- Fungal and Parasitic InfectionsATG Genes Influence the Virulence of Cryptococcus neoformans through Contributions beyond Core Autophagy Functions
The process of autophagy is conserved among all eukaryotes from yeast to humans and is mainly responsible for bulk degradation of cellular contents and nutrient recycling during starvation. Autophagy has been suggested to play a role in the pathogenesis of the opportunistic human fungal pathogen Cryptococcus neoformans, potentially through a contribution to the export...
- Fungal and Parasitic InfectionsInvadosome-Mediated Human Extracellular Matrix Degradation by Entamoeba histolytica
Entamoeba histolytica is a protozoan parasite that causes invasive amoebiasis when it invades the human colon. Tissue invasion requires a shift from an adhesive lifestyle in the colonic lumen to a motile and extracellular matrix (ECM) degradative lifestyle in the colonic tissue layers.
Microbial Immunity and Vaccines
- Microbial Immunity and VaccinesIdentification of Mycobacterial Ribosomal Proteins as Targets for CD4+ T Cells That Enhance Protective Immunity in Tuberculosis
Mycobacterium tuberculosis remains a threat to global health, and a more efficacious vaccine is needed to prevent disease caused by M. tuberculosis. We previously reported that the mycobacterial ribosome is a major target of CD4+ T cells in mice immunized with a genetically modified...
- Microbial Immunity and VaccinesTailoring a Plasmodium vivax Vaccine To Enhance Efficacy through a Combination of a CSP Virus-Like Particle and TRAP Viral Vectors
Vivax malaria remains one of the most serious and neglected tropical diseases, with 132 to 391 million clinical cases per year and 2.5 billion people at risk of infection. A vaccine against Plasmodium vivax could have more impact than any other intervention, and the use of a vaccine targeting multiple antigens may result in higher efficacy against sporozoite infection...
- Microbial Immunity and VaccinesTerminal Deoxynucleotidyl Transferase Is Not Required for Antibody Response to Polysaccharide Vaccines against Streptococcus pneumoniae and Salmonella enterica Serovar Typhi
B cell antigen receptor (BCR) diversity increases by several orders of magnitude due to the action of terminal deoxynucleotidyl transferase (TdT) during V(D)J recombination. Unlike adults, infants have limited BCR diversity, in part due to reduced expression of TdT.
- Microbial Immunity and Vaccines | SpotlightPD-L1, TIM-3, and CTLA-4 Blockade Fails To Promote Resistance to Secondary Infection with Virulent Strains of Toxoplasma gondii
T cell exhaustion is a state of hyporesponsiveness that develops during many chronic infections and cancer. Neutralization of inhibitory receptors, or “checkpoint blockade,” can reverse T cell exhaustion and lead to beneficial prognoses in experimental and clinical settings.
- Microbial Immunity and Vaccines | SpotlightStandardization of Pneumococcal Biofilm Release to PncO Expression, a Predictive Measurement of Virulence
A critical component in clinical trials for vaccines against pneumococcal disease is the establishment of robust preclinical models and clinical correlates of protection, which, in the case of the causative bacterial agent Streptococcus pneumoniae, include standard sepsis/pneumonia mouse models and opsonophagocytic activity (OPA), respectively. Despite broad usage,...
- Microbial Immunity and VaccinesTransgenic Eimeria tenella Expressing Profilin of Eimeria maxima Elicits Enhanced Protective Immunity and Alters Gut Microbiome of Chickens
Coccidiosis is one of the most serious diseases of livestock and birds in the world. Vaccination with live-parasite anticoccidial vaccines with genetic manipulation improving the immunogenicity of vaccine strains would be the best means for controlling coccidiosis in breeder and layer stocks, even in fast-growing broilers.
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