Summary Symptomatic gonococcal infection, caused by the pathogen Neisseria gonorrhoeae (Gc), is characterized influx of polymorphonuclear leukocytes (PMNs) to site infection. Although PMNs possess several mechanisms oxidative killing, intact Gc can be found associated with PMNs, suggesting that defences against stress are crucial for its ability evade killing PMNs. We used microarrays identify genes were differentially expressed after transient exposure hydrogen peroxide (H 2 O ). Of 75...

The pilin antigenic variation (Av) system of Neisseria gonorrhoeae (Gc) mediates unidirectional DNA recombination from silent gene copies into the expression locus. A sequencing assay was developed to accurately measure Av in a population Gc strain FA1090 arising defined progenitor under non-selective culture conditions. This employs piliated parental variant with recA allele whose promoter is replaced by lac-regulatory elements, allowing for controlled induction Av. From this assay,...

Central to the field of bacterial pathogenesis is ability define if and how microbes survive after exposure eukaryotic cells. Current protocols address these questions include colony count assays, gentamicin protection electron microscopy. Colony assays only assess viability entire population are unable determine individual viability. Electron microscopy can be used bacteria provide information regarding their localization in host However, often display a range densities, making assessment...

Acute gonorrhea is characterized by neutrophilic inflammation that insufficient to clear Neisseria gonorrhoeae. Activated neutrophils release extracellular traps (NETs), which are composed of chromatin and decorated with antimicrobial proteins. The N. gonorrhoeae NG0969 open reading frame contains a gene (nuc) encodes putatively secreted thermonuclease (Nuc) contributes biofilm remodeling. Here, we report Nuc degrades NETs help resist killing neutrophils. Primary human released after...

Abstract CR3 (CD11b/CD18; αmβ2 integrin) is a conserved phagocytic receptor. The active conformation of binds the iC3b fragment complement C3 as well many host and microbial ligands, leading to actin-dependent phagocytosis. There are conflicting reports about how engagement affects fate phagocytosed substrates. Using imaging flow cytometry, we confirmed that binding internalization iC3b-opsonized polystyrene beads by primary human neutrophils was CR3-dependent. did not stimulate neutrophil...

Symptomatic infection with Neisseria gonorrhoeae (Gc) results in a potent polymorphonuclear leukocyte (PMN)-driven inflammatory response, but the mechanisms by which Gc withstands PMN attack are poorly defined. Here we report that can suppress oxidative burst, central component of antimicrobial arsenal. Primary human PMNs remained viable after exposure to liquid-grown, exponential-phase, opacity-associated protein (Opa)-negative strains FA1090 and MS11 did not generate reactive oxygen...

Symptomatic infection with Neisseria gonorrhoeae (Gc) is characterized by abundant neutrophil (PMN, polymorphonuclear leucocyte) influx, but PMNs cannot clear initial infection, indicating that Gc possess defences against PMN challenge. In this study, survival of liquid-grown was monitored after synchronous adherent, interleukin 8-treated human PMNs. 40-70% FA1090 survived 1 h exposure, which bacterial numbers increased. Assays viability dyes along soybean lectin to detect extracellular...

Infection with the human-specific bacterial pathogen Neisseria gonorrhoeae triggers a potent, local inflammatory response driven by polymorphonuclear leukocytes (neutrophils or PMNs). PMNs are terminally differentiated phagocytic cells that vital component of host innate immune and first responders to fungal infections. possess diverse arsenal components combat microorganisms, including production reactive oxygen species release degradative enzymes antimicrobial peptides. Despite numerous at...

ABSTRACT The Neisseria gonorrhoeae (the gonococcus [Gc]) opacity-associated (Opa) proteins mediate bacterial binding and internalization by human epithelial cells neutrophils (polymorphonuclear leukocytes [PMNs]). Investigating the contribution of Opa to gonococcal pathogenesis is complicated high-frequency phase variation opa genes. We therefore engineered a derivative Gc strain FA1090 in which all genes were deleted frame, termed Opaless. Opaless remained uniformly negative (Opa − ),...

Symptomatic infection with Neisseria gonorrhoeae (Gc) promotes inflammation driven by polymorphonuclear leucocytes (PMNs, neutrophils), yet some Gc survive PMN exposure during infection. Here we report a novel mechanism of gonococcal resistance to PMNs: phagosomes avoid maturation into phagolysosomes delayed fusion primary (azurophilic) granules, which contain antimicrobial components including serine proteases. Reduced phagosome-primary granule was observed in gonorrheal exudates and human...

ABSTRACT Neisseria gonorrhoeae successfully overcomes host strategies to limit essential nutrients, termed nutritional immunity, by production of TonB-dependent transporters (TdTs)—outer membrane proteins that facilitate nutrient transport in an energy-dependent manner. Four gonococcal TdTs utilization iron or chelates from host-derived proteins, including transferrin (TbpA), lactoferrin (LbpA), and hemoglobin (HpuB), addition xenosiderophores other bacteria (FetA). The roles the remaining...

Symptomatic infection by Neisseria gonorrhoeae (Gc) produces a potent inflammatory response, resulting in neutrophil-rich exudate. A population of Gc can survive the killing activities neutrophils for reasons not completely understood. Unlike other Gram-negative bacteria, releases monomeric peptidoglycan (PG) extracellularly, dependent on two nonessential, nonredundant lytic transglycosylases (LTs), LtgA and LtgD. PG released LtgD stimulate host immune responses. We report that ΔltgAΔltgD...

The mucosal inflammatory response to Neisseria gonorrhoeae (Gc) is characterized by recruitment of neutrophils the site infection. Gc survives exposure limiting ability make antimicrobial products and expressing factors that defend against these products. multiple transferable resistance (Mtr) system a tripartite efflux pump, comprised inner membrane MtrD, periplasmic attachment protein MtrC, outer channel MtrE. MtrCDE exports diverse array substrates, including certain detergents, dyes,...

The complement cascade is a front-line defense against pathogens. Complement activation generates the membrane attack complex (MAC), 10-11 nm diameter pore formed by proteins C5b through C8 and polymerized C9. MAC embeds within outer of Gram-negative bacteria displays bactericidal activity. In absence C9, C5b-C8 complexes can form 2-4 pores on membranes, but their relevance to microbial control poorly understood. Deficiencies in terminal components uniquely predispose individuals infections...

Polymorphonuclear leukocytes (PMNs) are terminally differentiated phagocytes with pivotal roles in infection, inflammation, tissue injury, and resolution. PMNs display a breadth of responses to diverse endogenous exogenous stimuli, making understanding these innate immune responders vital yet challenging achieve. Here, we report 22-color spectral flow cytometry panel profile primary human for surface marker expression activation, degranulation, phagocytosis, migration, chemotaxis,...

The complement cascade is a front-line defense against pathogens. Complement activation generates the membrane attack complex (MAC), 10-11 nm diameter pore formed by proteins C5b through C8 and polymerized C9. MAC embeds within outer of Gram-negative bacteria displays bactericidal activity. In absence C9, C5b-C8 complexes can form 2-4 pores on membranes, but their relevance to microbial control poorly understood. Deficiencies in terminal components uniquely predispose individuals infections...

ABSTRACT The bacterial pathogen Salmonella typhimurium colonizes its animal hosts by inducing internalization into intestinal epithelial cells. This process requires reorganization of the actin cytoskeleton apical plasma membrane elaborate ruffles that engulf bacteria. Members Rho family small GTPases are critical regulators structure, and in nonpolarized cells, GTPase Cdc42 has been shown to modulate entry. Because architecture cells is organized differently from we examined role two...

ABSTRACT The sexually transmitted infection gonorrhea is caused exclusively by the human-specific pathogen Neisseria gonorrhoeae . Type IV pili are an essential virulence factor uniformly expressed on clinical gonococcal isolates and required for several aspects of pathogenesis, including adherence to host tissues, autoagglutination, twitching motility, uptake DNA during transformation. Symptomatic characterized influx neutrophils or polymorphonuclear leukocytes (PMNs) site infection. PMNs a...

ABSTRACT Neisseria gonorrhoeae (the gonococcus, Gc) triggers a potent inflammatory response and recruitment of neutrophils to the site infection. Gc survives exposure despite these cells' antimicrobial products, such as reactive oxygen species (ROS). ROS production in is initiated by NADPH oxidase, which converts into superoxide. The subunits oxidase are spatially separated between granules (gp91 phox /p22 ) cytoplasm (p47 , p67 p40 ). Activation promotes coassembly at phagosome and/or...