Cellular Activity of Typhimurium ArtAB Toxin and Its Receptor-Binding Subunit.

Salmonellosis is among the most reported foodborne illnesses in the United States. The Typhimurium DT104 phage type, which is associated with multidrug-resistant disease in humans and animals, possesses an ADP-ribosylating toxin called ArtAB. Full-length AB has been found on a number of broad-host-range non-typhoidal species and serovars.

Evaluation of the Efficacy of a Cholera-Toxin-Based Vaccine against Bovine Intramammary Challenge.

() is a primary agent of bovine mastitis and a source of significant economic loss for the dairy industry. We previously reported antigen-specific immune induction in the milk and serum of dairy cows following vaccination with a cholera toxin A and B subunit (CTA/B) based vaccine containing the iron-regulated surface determinant A (IsdA) and clumping factor A (ClfA) antigens of (IsdA + ClfA-CTA/B). The goal of the current study was to assess the efficacy of this vaccine to protect against infection after intramammary challenge.

Center of Biomedical Research Excellence in Matrix Biology: Building Research Infrastructure, Supporting Young Researchers, and Fostering Collaboration.

The Center of Biomedical Research Excellence in Matrix Biology strives to improve our understanding of extracellular matrix at molecular, cellular, tissue, and organismal levels to generate new knowledge about pathophysiology, normal development, and regenerative medicine. The primary goals of the Center are to i) support junior investigators, ii) enhance the productivity of established scientists, iii) facilitate collaboration between both junior and established researchers, and iv) build biomedical research infrastructure that will support research relevant to cell-matrix interactions in disease progression, tissue repair and regeneration, and v) provide access to instrumentation and technical support. A Pilot Project program provides funding to investigators who propose applying their expertise to matrix biology questions.

Expression, immunogenicity and variation of iron-regulated surface protein A from bovine isolates of Staphylococcus aureus.

Staphylococcus aureus iron-regulated surface protein A (IsdA) is a fibrinogen and fibronectin adhesin that also contributes to iron sequestration and resistance to innate immunity. IsdA is conserved in human isolates and has been investigated as a human vaccine candidate. Here we report the expression of isdA, the efficacy of anti-IsdA responses and the existence of IsdA sequence variants from bovine Staphylococcus.

Burrowing Owls, Pulex irritans, and Plague.

Western Burrowing Owls (Athene cunicularia hypugaea) are small, ground-dwelling owls of western North America that frequent prairie dog (Cynomys spp.) towns and other grasslands. Because they rely on rodent prey and occupy burrows once or concurrently inhabited by fossorial mammals, the owls often harbor fleas.

Immunogenicity of a West Nile virus DIII-cholera toxin A2/B chimera after intranasal delivery.

West Nile virus (WNV) causes potentially fatal neuroinvasive disease and persists at endemic levels in many parts of the world. Despite advances in our understanding of WNV pathogenesis, there remains a significant need for a human vaccine. The domain III (DIII) region of the WNV envelope protein contains epitopes that are the target of neutralizing antibodies.

Mucosal immunization with a Staphylococcus aureus IsdA-cholera toxin A2/B chimera induces antigen-specific Th2-type responses in mice.

Staphylococcus aureus is a leading cause of opportunistic infection worldwide and a significant public health threat. The iron-regulated surface determinant A (IsdA) adhesin is essential for S. aureus colonization on human nasal epithelial cells and plays an important role in iron acquisition and resistance to human skin defenses.

Purification and characterization of Yersinia enterocolitica and Yersinia pestis LcrV-cholera toxin A(2)/B chimeras.

Yersinia pestis is a virulent human pathogen and potential biological weapon. Despite a long history of research on this organism, there is no licensed vaccine to protect against pneumonic forms of Y. pestis disease.

Characterization of fluorescent chimeras of cholera toxin and Escherichia coli heat-labile enterotoxins produced by use of the twin arginine translocation system.

Cholera toxin (CT) is an AB(5) toxin responsible for the profuse secretory diarrhea resulting from Vibrio cholerae infection. CT consists of a pentameric, receptor-binding B subunit (CTB) and a monomeric A subunit (CTA) that has latent enzymatic activity. In addition to its enterotoxicity, CT has potent mucosal adjuvant activity and can also function as a carrier molecule with many potential applications in cell biology.

Cholera holotoxin assembly requires a hydrophobic domain at the A-B5 interface: mutational analysis and development of an in vitro assembly system.

Cholera toxin (CT) and related Escherichia coli enterotoxins LTI and LTIIb have a conserved hydrophobic region at the AB(5) interface postulated to be important for toxin assembly. Hydrophobic residue F223 in the A subunit of CT (CTA) as well as residues 174, L77, and T78 in the B subunit of CT (CTB) were replaced individually with aspartic acid, and the resulting CTA and CTB variants were analyzed for their ability to assemble into holotoxin in vivo. CTA-F223D holotoxin exhibited decreased stability and toxicity and increased susceptibility to proteolysis by trypsin.

FimZ binds the Salmonella typhimurium fimA promoter region and may regulate its own expression with FimY.

The FimZ protein, an activator of FimA production in Salmonella typhimurium, acts in conjunction with FimY to facilitate the expression of type 1 fimbriae. The predicted amino acid sequence of FimZ suggests that this protein may be a DNA-binding protein related to BvgA, a sensory regulator of virulence gene expression in Bordetella pertussis. Purification of FimZ following overexpression of the protein by a strong inducible promoter and gel mobility shift assays confirm that FimZ is a 25-kDa polypeptide that binds to the promoter region offimA.