Intrinsic p53 activation restricts gammaherpesvirus driven germinal center B cell expansion during latency establishment.

Gammaherpesviruses are DNA tumor viruses that establish lifelong latent infections in lymphocytes. For viruses such as Epstein-Barr virus and murine gammaherpesvirus 68, this is accomplished through a viral gene-expression program that promotes cellular proliferation and differentiation, especially of germinal center B cells. Intrinsic host mechanisms that control virus-driven cellular expansion are incompletely defined.

Flow cytometric measurement of CFTR-mediated chloride transport in human neutrophils.

Immune cells express a variety of ion channels and transporters in the plasma membrane and intracellular organelles, responsible of the transference of charged ions across hydrophobic lipid membrane barriers. The correct regulation of ion transport ensures proper immune cell function, activation, proliferation, and cell death. Cystic fibrosis (CF) is a genetic disease in which the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) chloride channel gene is defective, consequently, the CFTR protein is dysfunctional, and the chloride efflux in CF cells is markedly impaired.

Associations among rearing environment and the infant gut microbiome with early-life neurodevelopment and cognitive development in a nonhuman primate model ().

Early gut microbiome development may impact brain and behavioral development. Using a nonhuman primate model (), we investigated the association between social environments and the gut microbiome on infant neurodevelopment and cognitive function. Infant rhesus monkeys ( = 33) were either mother-peer-reared (MPR) or nursery-reared (NR).

MtlD as a therapeutic target for intestinal and systemic bacterial infections.

Unlabelled: The ability to treat infections is threatened by the rapid emergence of antibiotic resistance among pathogenic microbes. Therefore, new antimicrobials are needed. Here we evaluate mannitol-1-phosphate 5-dehydrogenase (MtlD) as a potential new drug target.

Functional role of the biofilm regulator CsgD in sv. Typhi.

Introduction: Typhoid fever is an infectious disease primarily caused by sv. Typhi ( Typhi), a bacterium that causes as many as 20 million infections and 600,000 deaths annually. Asymptomatic chronic carriers of S.

Neutrophil NADPH oxidase promotes bacterial eradication and regulates NF-κB-Mediated inflammation via NRF2 signaling during urinary tract infections.

The precise role of neutrophil-derived reactive oxygen species (ROS) in combating bacterial uropathogens during urinary tract infections (UTI) remains largely unexplored. In this study, we elucidate the antimicrobial significance of NADPH oxidase 2 (NOX2)-derived ROS, as opposed to mitochondrial ROS, in facilitating neutrophil-mediated eradication of uropathogenic Escherichia coli (UPEC), the primary causative agent of UTI. Furthermore, NOX2-derived ROS regulate NF-κB-mediated inflammatory responses in neutrophils against UPEC by inducing the release of nuclear factor erythroid 2-related factor 2 (Nrf2) from its inhibitor, Kelch-like ECH-associated protein 1 (Keap1).

The Neisseria meningitidis urethritis clade (NmUC) acts as a "chimeric pathogen" during infection of primary, human male, urethral epithelial cells.

Background: Clusters of male urethritis cases, caused by a novel clade of non-groupable Neisseria meningitidis (NmUC, "the clade"), have been reported globally. Genetic features unique to NmUC isolates include: the acquisition of the gonococcal denitrification loci, norB-aniA; a unique factor H binding protein (fHbp) variant; and loss of group C capsule and intrinsic lipooligosaccharide sialylation. We hypothesized that these characteristics might confer a colonization and survival advantage to NmUC during male urethral infection relative to non-clade group C Neisseria meningitidis.

Gcn2 rescues reprogramming in the absence of Hog1/p38 signaling in during thermal stress.

The fungus is an opportunistic pathogen of humans that reprograms its translatome to facilitate adaptation and virulence within the host. We studied the role of Hog1/p38 in reprogramming translation during thermal stress adaptation and found that this pathway acts on translation crosstalk with the Gcn2 pathway, a well-studied regulator of general translation control. Using a combination of molecular assays and phenotypic analysis, we show that increased output from the Gcn2 pathway in a Hog1 deletion mutant is associated with rescue of thermal stress adaptation at both molecular and phenotypic scales.

A temporary cholesterol-rich diet and bacterial extracellular matrix factors favor spp. biofilm formation in the cecum.

Asymptomatic chronic carriers occur in approximately 5% of humans infected with serovar Typhi (. Typhi) and represent a critical reservoir for bacterial dissemination. While chronic carriage primarily occurs in the gallbladder (GB) through biofilms on gallstones, additional anatomic sites have been suggested that could also harbor .

Methods for detecting and monitoring Salmonella infection and chronic carriage in living mice using bioluminescent in vivo imaging.

serovar Typhi primarily persists in chronic carriers by forming biofilms on gallstones in the gallbladder. We have developed a gallstone mouse model to study chronic carriage. To better understand the infection timeline and differentiate between mice that have maintained long-term gallbladder carriage from those that have cleared infection, we utilized bioluminescent .

Typhi Haplotype 58 biofilm formation and genetic variation in isolates from typhoid fever patients with gallstones in an endemic setting in Kenya.

Although typhoid fever has largely been eliminated in high-income countries, it remains a major global public health concern especially among low- and middle-income countries. The causative agent, serovar Typhi ( Typhi), is a human restricted pathogen with a limited capacity to replicate outside the human host. Human carriers, 90% of whom have gallstones in their gallbladder, continue to shed the pathogen for an ill-defined period of time after treatment.

Antagonistic Effects of Actin-Specific Toxins on Typhimurium Invasion into Mammalian Cells.

Competition between bacterial species is a major factor shaping microbial communities. It is possible but remains largely unexplored that competition between bacterial pathogens can be mediated through antagonistic effects of bacterial effector proteins on host systems, particularly the actin cytoskeleton. Using Typhimurium invasion into cells as a model, we demonstrate that invasion is inhibited if the host actin cytoskeleton is disturbed by actin-specific toxins, namely, MARTX actin crosslinking (ACD) and Rho GTPase inactivation (RID) domains, TccC3, and 's own SpvB.

Extracellular DNA-protein interactions.

Intracellular DNA primarily serves as the cellular genetic material both in eukaryotes and prokaryotes. This function is often regulated by alterations in the DNA structure to accommodate transcription, recombination, and DNA replication. Extracellularly, both eukaryotic and prokaryotic cells take advantage of DNA plenty in addition to a permissive environment and create novel structures to fulfill multiple new roles.

Inflammasome-mediated pyroptosis in defense against pathogenic bacteria.

Macrophages, neutrophils, and epithelial cells are pivotal components of the host's immune response against bacterial infections. These cells employ inflammasomes to detect various microbial stimuli during infection, triggering an inflammatory response aimed at eradicating the pathogens. Among these inflammatory responses, pyroptosis, a lytic form of cell death, plays a crucial role in eliminating replicating bacteria and recruiting immune cells to combat the invading pathogen.

Limited proteolysis of neutrophil granule proteins by the bacterial protease RgpB depletes neutrophil antimicrobial capacity.

Neutrophils are highly abundant in the gingival tissues where they play an essential role in immune homeostasis by preventing microbial invasion. Here, we show that the oral periodontal pathogen Porphyromonas gingivalis utilizes its cysteine proteases (gingipains) to disengage phagosomal antimicrobial capacity. Arginine gingipains are a sub-family of trypsin-like proteases produced by P.

Noninflammatory 97-amino acid High Mobility Group Box 1 derived polypeptide disrupts and prevents diverse biofilms.

Background: Bacterial biofilm communities are embedded in a protective extracellular matrix comprised of various components, with its' integrity largely owed to a 3-dimensional lattice of extracellular DNA (eDNA) interconnected by Holliday Junction (HJ)-like structures and stabilised by the ubiquitous eubacterial DNABII family of DNA-binding architectural proteins. We recently showed that the host innate immune effector High Mobility Group Box 1 (HMGB1) protein possesses extracellular anti-biofilm activity by destabilising these HJ-like structures, resulting in release of biofilm-resident bacteria into a vulnerable state. Herein, we showed that HMGB1's anti-biofilm activity was completely contained within a contiguous 97 amino acid region that retained DNA-binding activity, called 'mB Box-97'.

Deciphering the relative importance of genetic elements in hypervirulent Klebsiella pneumoniae to guide countermeasure development.

Background: Quantitating the contribution of phenotype-responsible elements in hypervirulent Klebsiella pneumoniae is needed.

Methods: Isogenic mutants of four hypervirulent clinical isolates that produced K1 (ST23), K2 (ST86), K20 (ST1544), or K54 (ST29) capsules (mean 2.2 log LD (range 1.