The Tol-Pal system of Gram-negative bacteria is necessary for maintaining outer membrane integrity. It a multiprotein complex five envelope proteins, TolQ, TolR, TolA, TolB, and Pal. These proteins were first investigated in E. coli, subsequently been identified many other bacterial genera. However, the function Salmonella Choleraesuis pathogenesis still unclear. Here, we reported role three these phenotype biology S. Choleraesuis. We found that mutations tolA, tolB, tolR caused severe...

ABSTRACT We have developed a regulated delayed antigen synthesis (RDAS) system for use in recombinant attenuated Salmonella vaccine (RASV) strains to enhance immune responses by reducing the adverse effects of high-level synthesis. This includes chromosomal repressor gene, lacI , expressed from arabinose-regulated araC P BAD promoter. LacI serves regulate expression plasmid promoter, trc that directs In presence arabinose is produced, which binds blocking vivo an arabinose-poor environment,...

Mycoplasma synoviae (M. synoviae) is a serious avian pathogen that causes significant economic losses to chicken and turkey producers worldwide. The currently available live attenuated inactivated vaccines provide limited protection. objective of this study was identify potential subunit vaccine candidates using immunoproteomics reverse vaccinology analyses evaluate their preliminary Twenty-four candidate antigens were identified, five them, namely RS01790 (a putative sugar ABC transporter...

We hypothesized that the immunogenicity of live Salmonella enterica serovar Typhi vaccines expressing heterologous antigens depends, at least in part, on its rpoS status. As part our project to develop a recombinant attenuated S. vaccine (RASTyV) prevent pneumococcal diseases infants and children, we constructed three RASTyV strains synthesizing Streptococcus pneumoniae surface protein PspA test this hypothesis. Each vector strain carried ten engineered mutations designed optimize safety...

ABSTRACT Streptococcus pneumoniae is a leading cause of morbidity and mortality among children worldwide particularly in developing countries. In this study, we evaluated PsaA, conserved antigen important for S. adhesion to invasion into nasopharynx epithelia, its ability induce protective immunity against challenge when delivered by recombinant attenuated Salmonella vaccine (RASVs) strains. RASVs were engineered synthesize PsaA peptides various lengths. Vaccination with an RASV synthesizing...

Induction of strong immune responses against a vectored antigen in hosts immunized with live attenuated Salmonella vaccines is related part to the amount delivered and overall fitness vector relation its ability stimulate host system. Constitutive high-level synthesis causes metabolic burden vaccine strain that can reduce strain's interact lymphoid tissues, resulting compromised response. A solution this problem use systems regulate gene expression, permitting high levels only after has...

The genotypes of the H9N2 avian influenza viruses have changed since 2013 when almost all circulating in chickens China were genotype 57 (G57) with fittest lineage each gene. To characterize variant from 2011 to 2014, 28 isolated live poultry markets 2011–2014 and analyzed by genetic biological characterization. Our findings showed that 16 residues antigenicity, two potential N-linked glycosylation sites, one amino acid receptor binding site HA protein significantly 2011–2014. Moreover, NA...

Outbreaks of Marek's disease (MD), caused by virus (MDV), primarily occur in 10–12-week-old hens. We report a case MD breeding flock 24–30-week-old vaccinated broilers China. The clinical signs the affected chickens appeared at 24 weeks, and incidence tumours peaked 30 weeks. morbidity mortality hens were 5 % 80 %, respectively. Hematoxylin–eosin staining tissues showed typical characteristics MD. MDV infection was confirmed with an agar gel diffusion precipitation assay for antigen feather...

Abstract Salmonella is an important food-borne pathogen associated with public health and high economic losses. To investigate the prevalence characteristics of in a pig slaughterhouse Yangzhou, total 80 isolates were isolated from 459 (17.43%) samples 2016–2017. S. Derby (35/80, 43.75%) was most prevalent, followed by Rissen (16/80, 20.00%) Newlands (11/80, 13.75%). The highest rates susceptibility observed to cefoxitin (80/80, 100.0%) amikacin 100.0%), aztreonam (79/80, 98.75%)...

Bacterial outer membrane vesicles (OMVs) are considered a promising vaccine platform for their high built-in adjuvanticity and ability to efficiently induce immune responses. OMVs can be engineered with heterologous antigens based on genetic engineering strategies. However, several critical issues should still validated, including optimal exposure the OMV surface, increased production of foreign antigens, nontoxicity, induction powerful protection. In this study, lipoprotein transport...

H9N2 avian influenza virus has spread worldwide, and vaccination with an inactivated is currently the major prevention method in China. To further understand effect of selection pressure from antibodies on evolution virus, F/98 (A/Chicken/Shanghai/F/98), which vaccine representative East China, was used for serial passaging 20 generations chickens without vaccination. After plaque purification trachea lung tissues, 390 quasispecies were obtained. The second-generation under had undergone...

Infectious bronchitis (IB) is a highly infectious viral disease of chickens which causes significant economic losses in the poultry industry worldwide. An effective vaccine against IB urgently needed to provide both biosafety and high-efficiency immune protection. In this study, S1 protein virus was delivered by recombinant attenuated Salmonella typhimurium vector form candidate χ11246(pYA4545-S1). S. χ11246 carried sifA− mutation with regulated delayed systems, striking balance between host...

We are developing a Salmonella vectored vaccine to prevent infant pneumonia and other diseases caused by Streptococcus pneumoniae. One prerequisite for achieving this goal is construct evaluate new recombinant attenuated (RASV) strains suitable use in neonates infants. enterica serovar Typhimurium strain chi9558(pYA4088) specifies delivery of the pneumococcal protective antigen PspA can protect adult mice from challenge with S. This completely safe oral day-old mice. Here we assess...

A/Chicken/Beijing/1/94 (Ck/BJ/1/94) avian influenza virus (AIV), a prototype of the H9N2 subtype, is phylogenetically similar in its hemagglutinin (HA) and neuraminidase (NA) genes to A/Chicken/Shanghai/F/98 (Ck/SH/F/98; H9N2) AIV, natural reassortant between different sublineages. To understand role HA NA airborne transmission we compared route relative replication efficiency these strains specific-pathogen-free chickens. Three recombinant viruses were generated by reverse genetics,...

Streptococcus suis is one of the major pathogens that cause economic losses in swine industry worldwide. However, current bacterins only provide limited prophylactic protection field. An ideal vaccine against S. should protect pigs clinical diseases caused by multiple serotypes, or at least dominant serotype a given geographic region. A new recombinant Salmonella enterica Choleraesuis vector, rSC0011, based on regulated delayed attenuation system and antigen synthesis system, was developed...

ABSTRACT Colanic acid (CA) is a common exopolysaccharide produced by many genera in the Enterobacteriaceae . It critical for biofilm formation on HEp-2 cells and chicken intestinal tissue Salmonella In this study, we generated different CA synthesis gene mutants evaluated immune responses induced these mutants. One of mutations, Δ( wza-wcaM ) 8 , which deleted whole operon synthesis, was introduced into two vaccine strains attenuated auxotrophic traits or regulated delayed attenuation...

Vaccines constitute a unique selective pressure, different from natural selection, drives the evolution of influenza virus. In this study, A/Chicken/Shanghai/F/1998 (H9N2) was continually passaged in specific pathogen-free embryonated chicken eggs with or without pressures antibodies induced by homologous maternal antibodies. Genetic mutations, antigenic drift, replication, and pathogenicity virus were evaluated. Antigenic drift viruses occurred 47th generation (vF47) under pressure on 52nd...

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative intracellular pathogen that damages gastrointestinal tissue and causes severe diarrhoea. The mechanisms by which disrupts epithelial barrier increases the paracellular permeability are incompletely understood. Our present study aims to determine role of Gli1, transcription factor activated in sonic hedgehog (Shh) pathway, decreasing levels apical junction proteins Salmonella-infected human colonic cancer cell line,...