From bacteria to biomedicine: Developing therapies exploiting NAD metabolism.

Nicotinamide adenine dinucleotide (NAD) serves as a critical cofactor in cellular metabolism and redox reactions. Bacterial pathways rely on NAD participation, where its stability and concentration govern essential homeostasis and functions. This review delves into the role and metabolic regulation of NAD in bacteria, highlighting its influence on physiology and virulence.

Comparative genomics of Brucella abortus and Brucella melitensis unravels the gene sharing, virulence factors and SNP diversity among the standard, vaccine and field strains.

Brucella abortus and Brucella melitensis are the primary etiological agents of brucellosis in large and small ruminants, respectively. There are limited comparative genomic studies involving Brucella strains that explore the relatedness among both species. In this study, we involved strains (n=44) representing standard, vaccine and Indian field origin for pangenome, single nucleotide polymorphism (SNP) and phylogenetic analysis.

Dissection of a sensorimotor circuit underlying pathogen aversion in C. elegans.

Background: Altering animal behavior to reduce pathogen exposure is a key line of defense against pathogen attack. In Caenorhabditis elegans, alterations in intestinal physiology caused by pathogen colonization and sensation of microbial metabolites may lead to activation of pathogen aversive behaviors ranging from aversive reflexes to learned avoidance. However, the neural circuitry between chemosensory neurons that sense pathogenic bacterial cues and the motor neurons responsible for avoidance-associated locomotion remains unknown.

The gut efflux pump MRP-1 exports oxidized glutathione as a danger signal that stimulates behavioral immunity and aversive learning.

Innate immune surveillance, which monitors the presence of potentially harmful microorganisms and the perturbations of host physiology that occur in response to infections, is critical to distinguish pathogens from beneficial microbes. Here, we show that multidrug resistance-associated protein-1 (MRP-1) functions in the basolateral membrane of intestinal cells to transport byproducts of cellular redox reactions to control both molecular and behavioral immunity in Caenorhabditis elegans. Pseudomonas aeruginosa infection disrupts glutathione homeostasis, leading to the excess production of the MRP-1 substrate, oxidized glutathione (GSSG).

Immunization with S19Δ Conferred Protection in Water Buffaloes against Virulent Challenge with Strain S544.

Vaccination of cattle and buffaloes with strain 19 has been the mainstay for control of bovine brucellosis. However, vaccination with S19 suffers major drawbacks in terms of its safety and interference with serodiagnosis of clinical infection. S19∆, a perosamine synthetase B gene deletion mutant, overcomes the drawbacks of the S19 vaccine strain.

TRPM channels mediate learned pathogen avoidance following intestinal distention.

Upon exposure to harmful microorganisms, hosts engage in protective molecular and behavioral immune responses, both of which are ultimately regulated by the nervous system. Using the nematode , we show that ingestion of leads to a fast pathogen avoidance behavior that results in aversive learning. We have identified multiple sensory mechanisms involved in the regulation of avoidance of The G-protein coupled receptor NPR-1-dependent oxygen-sensing pathway opposes this avoidance behavior, while an ASE neuron-dependent pathway and an AWB and AWC neuron-dependent pathway are directly required for avoidance.

Microbial colonization induces histone acetylation critical for inherited gut-germline-neural signaling.

The gut-neural axis plays a critical role in the control of several physiological processes, including the communication of signals from the microbiome to the nervous system, which affects learning, memory, and behavior. However, the pathways involved in gut-neural signaling of gut-governed behaviors remain unclear. We found that the intestinal distension caused by the bacterium Pseudomonas aeruginosa induces histone H4 Lys8 acetylation (H4K8ac) in the germline of Caenorhabditis elegans, which is required for both a bacterial aversion behavior and its transmission to the next generation.

Characterisation of Porcine Enteropathogenic Isolated in Northeastern India.

Introduction: Enteropathogenic (EPEC) is one of the main pathotypes causing gastroenteritis, particularly in young immunocompromised hosts. The study reports the prevalence, characterisation, and molecular epidemiology of EPEC from piglets in northeastern India.

Material And Methods: A total of 457 faecal samples were collected, from which 1,286 strains were isolated and screened by PCR.

Host Mucin Is Exploited by Pseudomonas aeruginosa To Provide Monosaccharides Required for a Successful Infection.

One of the primary functions of the mucosal barrier, found lining epithelial cells, is to serve as a first-line of defense against microbial pathogens. The major structural components of mucus are heavily glycosylated proteins called mucins. Mucins are key components of the innate immune system as they aid in the clearance of pathogens and can decrease pathogen virulence.

Brucella abortus S19 rfbD mutant is highly attenuated, DIVA enable and confers protection against virulent challenge in mice.

Brucella abortus S19 is an important tool for controlling bovine brucellosis across the globe. However, vaccination with S19 suffers critical shortcomings such as, presence of residual virulence, induction of abortion and sero-diagnostic interference. In this study, rfbD gene deleted mutant S19 was developed.

Partial protection induced by Salmonella based Brucella vaccine candidate in pregnant guinea pigs.

Residual virulence is a major drawback in current Brucella vaccines. Live vaccines induce abortions in pregnant animals. Hence, a novel anti-Brucella vaccine was developed utilizing rough Salmonella delivering four Brucella antigens.

Intranasally administered anti-Brucella subunit vaccine formulation induces protective immune responses against nasal Brucella challenge.

The present study was aimed to develop a safe and effective anti-Brucella subunit vaccine for mucosal protection against the respiratory exposure of Brucella infection. A chitosan-based Brucella nasal vaccine (BNV) was formulated using well-known Brucella immunogens, sodC, omp19, BLS and PrpA and tested against nasal Brucella challenge in BALB/c mice. The mice were intra-nasally vaccinated with sterile phosphate buffer saline (PBS), BNV or BNV plus Brucella LPS, and humoral (systemic IgG and mucosal IgA) and cell-mediated immune responses were analyzed.

Engineering of a rough auxotrophic mutant Typhimurium for effective delivery.

Live vaccine vectors offer a remarkable platform for delivering immunogens and therapeutic molecules by mimicking natural intracellular infections; however, pre-existing anti-vector immunity can impede effective deployment. Measures to alleviate pre-existing immunity include the use of heterologous vectors, development of highly attenuated strain enabling greater payload, removal of major immunoreactive components from the vector, and/or augmentation of delivered antigens via increased presentation in antigen presenting cells. Here we report a Typhimurium (ST) vector-JOL1800 that embodies these requisite properties.

Safety implication of Salmonella based Brucella vaccine candidate in mice and in vitro human cell culture.

An anti-Brucella vaccine candidate comprising rough Salmonella vector delivering Brucella antigens was developed. This system provides a platform for live Brucella-free vaccine development as it can mimic active-intracellular infection of Brucella organism. Exploiting this phenomenon thus provides significant protection at a single dose and also re-assured the safety.

Immuno-profiles of BALB/c mice inoculated with Salmonella vector delivering B-cell mitogen hydroxyproline epimerase.

The enzyme 4-hydroxyproline 2-epimerase (PrpA) involves in modulation of host immunity and is also reported as a potent B-cell mitogen. Live attenuated Salmonella Typhimurium (ST) vector constitutively expressing heterologous Brucella abortus PrpA protein (ST-PrpA) was inoculated in BALB/c mice in order to investigate the influence of the enzyme, on safety aspects, humoral and cellular immunity as well as protective efficacies against wild type challenges. No aggravation of morbidity was observed upon mice inoculation of ST-PrpA.

Effect of immunization routes and protective efficacy of antigens delivered via vector vaccine.

An anti- vaccine candidate comprised of purified lipopolysaccharide (LPS) and a cocktail of four Typhimurium (ST)- vectors was reported previously. Each vector constitutively expressed highly conserved antigens (rB), , lumazine synthase (BLS), proline racemase subunit A, outer membrane protein-19 (Omp19), and Cu-Zn superoxide dismutase (SOD). The present study determined a relative level of protection conferred by each single strain.

Immunization of guinea pigs with Salmonella delivered anti-Brucella formulation reduces organs bacterial load and mitigates histopathological consequences of Brucella abortus 544 challenge.

With an objective to generate safe and effective anti-Brucella vaccine, an attenuated live Salmonella Typhimurium vector delivering heterologous Brucella immunogenic proteins SOD, Omp19, BLS, and PrpA formulated with purified Brucella abortus lipopolysaccharide was evaluated on a guinea pig model. This model represents high susceptibility to Brucella infections and showed similarities in reproducing human pathologies. On safety perspectives, the vaccine formulation induced no observable alterations on general health and histology of the vaccinated guinea pigs.

Development and trial of vaccines against .

The search for ideal brucellosis vaccines remains active today. Currently, no licensed human or canine anti-brucellosis vaccines are available. In bovines, the most successful vaccine (S19) is only used in calves, as adult vaccination results in orchitis in male, prolonged infection, and possible abortion complications in pregnant female cattle.

Brucella lipopolysaccharide reinforced Salmonella delivering Brucella immunogens protects mice against virulent challenge.

Intracellular pathogen Salmonella exhibits natural infection broadly analogous to Brucella, this phenomenon makes Salmonella a pragmatic choice for an anti-Brucella vaccine delivery platform. In this study we developed and formulated a combination of four attenuated Salmonella Typhimurium live vector strains delivering heterologous Brucella antigens (rBs), namely lumazine synthase, proline racemase subunit A, lipoprotein outer membrane protein-19, and Cu-Zn superoxide dismutase. With an aim to develop a cross-protecting vaccine, Brucella pan-species conserved rBs were selected.

Pathogenic traits of Salmonella Montevideo in experimental infections in vivo and in vitro.

Salmonella serovar Montevideo (SM) is frequently associated with human Salmonella infections and causes gastrointestinal disease, cases are common particularly among individuals who come in close contact with live poultry or poultry meat products. To characterize SM disease in chickens, the pathogenic traits and tissue predilections of the disease were investigated. Dissemination of fluorescent-tagged SM (JOL1575GFP) was monitored after oral and intramuscular mock infections of specific-pathogen-free chickens.

A live attenuated mutant of Salmonella Montevideo triggers IL-6, IFN-γ and IL-12 cytokines that co-related with humoral and cellular immune responses required for reduction of challenge bacterial load in experimental chickens.

A live attenuated Salmonella enterica serovar Montevideo (SM) mutant JOL1599 was constructed by deletion of virulence-associated genes. The protective efficacy and immune response profiles of chickens immunized with JOL1599 were investigated. Immunized chickens demonstrated significant increases in plasma IgG and lymphocyte proliferative responses (P≤0.

Immunization with Salmonella Enteritidis secreting mucosal adjuvant labile toxin confers protection against wild type challenge via augmentation of CD3CD4 T-cell proliferation and enhancement of IFN-γ, IL-6 and IL-10 expressions in chicken.

The protective efficacy and immunological profiles of chickens immunized with an attenuated Salmonella Enteritidis (SE) constitutively secreting double mutant heat labile enterotoxin (dmLT) were investigated. The dmLT is a detoxified variant of Escherichia coli heat labile toxin and is a potent mucosal adjuvant capable of inducing both humoral and cell-mediated immunity. In this study, four-week-old chickens were inoculated with SE-dmLT strain JOL1641, parental SE strain JOL1087 or phosphate buffered saline control.

Virulence Associated Genes-Deleted Montevideo Is Attenuated, Highly Immunogenic and Confers Protection against Virulent Challenge in Chickens.

To construct a novel live vaccine against serovar Montevideo (SM) infection in chickens, two important bacterial regulatory genes, and , which are associated with invasion and virulence, were deleted from the wild type SM genome. Attenuated strains, JOL1625 (Δ), JOL1597 (Δ), and JOL1599 (ΔΔ) were thereby generated. Observations with scanning electron microscopy suggested that JOL1625 and JOL1599 cells showed increased ruffled surface which may be related to abundant extracellular polysaccharide (EPS) production.