Development of non-antibiotic-resistant, chromosomally based, constitutive and inducible expression systems for aroA-attenuated Salmonella enterica Serovar Typhimurium.

Live-vaccine delivery systems expressing two model antigens from Mycoplasma hyopneumoniae, F2(P97) (Adh) and NrdF, were constructed using Salmonella enterica serovar Typhimurium aroA (STM-1), and immunogenicity in mice was evaluated. Recombinant plasmid-based expression (PBE) and chromosomally based expression (CBE) systems were constructed. The PBE system was formed by cloning both antigen genes into pJLA507 to create an operon downstream of temperature-inducible promoters.

Differences in macrophage activation by bacterial DNA and CpG-containing oligonucleotides.

Bacterial DNA activates mouse macrophages, B cells, and dendritic cells in a TLR9-dependent manner. Although short ssCpG-containing phosphodiester oligonucleotides (PO-ODN) can mimic the action of bacterial DNA on macrophages, they are much less immunostimulatory than Escherichia coli DNA. In this study we have assessed the structural differences between E.

Investigation of ansB and sspA derived promoters for multi- and single-copy antigen expression in attenuated Salmonella enterica var. typhimurium.

Five candidate promoters were examined to determine their utility in directing immunogenic levels of expression of the C fragment from tetanus toxin in attenuated S. enterica used as an oral vaccine in mice. Promoters derived from the genes encoding the stringent starvation protein (sspA) from E.

Plasmid-encoded Tet B tetracycline resistance in Haemophilus parasuis.

The complete sequence of two plasmids, pHS-Tet (5.1 kb) and pHS-Rec (9.5 kb), isolated from Haemophilus parasuis strain HS1543 has been obtained.

Analysis of the role of pglI in pilin glycosylation of Neisseria meningitidis.

Pilin is the major subunit of the essential virulence factor pili and is glycosylated at Ser63. In this study we investigated the gene pglI to determine whether it is involved in the biosynthesis of the pilin-linked glycan of Neisseria meningitidis strain C311#3. A N.

Genetic analysis of a plasmid encoding haemocin production in Haemophilus paragallinarum.

The full sequence of plasmid p250, isolated from Haemophilus paragallinarum strain HP250, has been obtained. The plasmid contains seven ORFs: a putative integrase, a putative replication protein (repB) and five ORFs similar to those from the haemocin (bacteriocin) hmcDCBAI operon from Haemophilus influenzae. Of 19 other non-plasmid-containing H.

Molecular analysis of a haemagglutinin of Haemophilus paragallinarum.

The gene encoding a haemagglutinin of H. paragallinarum, hagA, has been identified and the full-length nucleotide sequence determined. A approximately 39 kDa protein, recognized by an anti-haemagglutinin monoclonal antibody, mAb4D, was purified from H.