Salmonella
Observation | Host-Microbe BiologyRIPK3-Dependent Recruitment of Low-Inflammatory Myeloid Cells Does Not Protect from Systemic Salmonella InfectionMacrophages employ multiple strategies to limit pathogen infection. For example, macrophages may undergo regulated cell death, including RIPK3-dependent necroptosis, as a means of combatting intracellular bacterial pathogens. However, bacteria have evolved mechanisms to evade or exploit immune responses. Salmonella is an intracellular pathogen that avoids and manipulates immune detection within macrophages. We examined the...
Research Article | Host-Microbe BiologyGenotoxic Effect of Salmonella Paratyphi A Infection on Human Primary Gallbladder CellsBacterial infections are increasingly being recognized as risk factors for the development of adenocarcinomas. The strong epidemiological evidence linking Helicobacter pylori infection to stomach cancer has paved the way to the demonstration that bacterial infections cause DNA damage in the host cells, initiating transformation. In this regard, the role of bacterial...
Research Article | Molecular Biology and PhysiologyAcetylation of Surface Carbohydrates in Bacterial Pathogens Requires Coordinated Action of a Two-Domain Membrane-Bound AcyltransferaseAcyltransferase-3 (AT3) domain-containing membrane proteins are involved in O-acetylation of a diverse range of carbohydrates across all domains of life. In bacteria they are essential in processes including symbiosis, resistance to antimicrobials, and biosynthesis of antibiotics. Their mechanism of action, however, is poorly characterized. We analyzed two acetyltransferases as models for this important family of membrane...
Observation | Molecular Biology and PhysiologyTumble Suppression Is a Conserved Feature of Swarming MotilityBacteria within a swarm move characteristically in packs, displaying an intricate swirling motion in which hundreds of dynamic rafts continuously form and dissociate as the swarm colonizes an increasing expanse of territory. The demonstrated property of E. coli to reduce its tumble bias and hence increase its run duration during swarming is expected to maintain and...
Research Article | Host-Microbe BiologyLinearized Siderophore Products Secreted via MacAB Efflux Pump Protect Salmonella enterica Serovar Typhimurium from Oxidative StressNontyphoidal Salmonella bacteria induce a classic inflammatory diarrhea by eliciting a large influx of neutrophils, producing a robust oxidative burst. Despite substantial progress understanding the benefits to the host of the inflammatory response to Salmonella, little is known regarding how Salmonella can simultaneously resist the damaging effects of the oxidative burst. The multidrug efflux pump MacAB...
Research Article | Host-Microbe BiologySpoT Induces Intracellular Salmonella Virulence Programs in the PhagosomePathogenic bacteria experience nutritional challenges during colonization and infection of mammalian hosts. Binding of the alarmone nucleotide guanosine tetraphosphate (ppGpp) to RNA polymerase coordinates metabolic adaptations and virulence gene transcription, increasing the fitness of diverse Gram-positive and Gram-negative bacteria as well as that of actinomycetes. Gammaproteobacteria such as Salmonella synthesize ppGpp by...
Research Article | Host-Microbe BiologyAn Advanced Human Intestinal Coculture Model Reveals Compartmentalized Host and Pathogen Strategies during Salmonella InfectionInfection research routinely employs in vitro cell cultures or in vivo mouse models as surrogates of human hosts. Differences between murine and human immunity and the low level of complexity of traditional cell cultures, however, highlight the demand for alternative models that combine the in vivo-like properties of the human system with straightforward experimental perturbation. Here, we introduce a 3D...
Research Article | Host-Microbe BiologyA Genome-Wide Knockout Screen in Human Macrophages Identified Host Factors Modulating Salmonella InfectionSalmonella exploits macrophages to gain access to the lymphatic system and bloodstream to lead to local and potentially systemic infections. With an increasing number of antibiotic-resistant isolates identified in humans, Salmonella infections have become major threats to public health. Therefore, there is an urgent need to identify alternative approaches to anti-infective therapy, including host-directed therapies. In...
Editor's Pick Research Article | Host-Microbe BiologyEstablishment of Chronic Typhoid Infection in a Mouse Carriage Model Involves a Type 2 Immune Shift and T and B Cell Recruitment to the GallbladderThe existence of chronic typhoid carriers has been in the public eye for over 100 years in part because of the publicity around Typhoid Mary. Additionally, it has been known for decades that the gallbladder is the main site of persistence and recently that gallstones play a key role. Despite this, very little is known about the physiological conditions that allow Salmonella...
Research Article | Ecological and Evolutionary ScienceSystems Biology and Pangenome of Salmonella O-AntigensLipopolysaccharides are a major component of the outer membrane in Gram-negative bacteria. They are composed of a conserved lipid structure that is embedded in the outer leaflet of the outer membrane and a polysaccharide known as the O-antigen. O-antigens are highly variable in structure across strains of a species and are crucial to a bacterium’s interactions with its environment. They constitute the first line of defense against both...