Detection of phospholipase a activity from campylobacter concisus

This was a conference oral presentation at the 2002 ASM Annual Scientific Meeting in Melbourne.<br /

Antigen Presentation Ability of Salmonella Carrying DNA Vaccine Model and MCP-3 gene

The objective of this study is to determine the antigen presentation ability of a DNA vaccine model that is co-delivered with that of recombinant Salmonella enterica serovar Typhimurium (STM1) expressing chemokine macrophage chemotactic protein-3 (MCP-3). The DNA vaccine, pVROVA, was constructed by amplification of the ovalbumin coding region from sOVA-C1. Dendritic cells (DCs) were obtained from IL-4 and GMCSF stimulated mouse bone marrow stem cell. Cultured DCs were incubated with STM1 carrying a model ovalbumin gene (pVROVA). Furthermore, MHC class I antigen presentation of a dominant OVA peptide was assayed in vitro. The experiments were designed to determine the effect of co-delivering MCP-3 with that of ovalbumin in STM1. Our results show that a plasmid pROVA-carrying ovalbumin gene was succesfully constructed and sequence analysis of the ovalbumin-coding revealed an identity match of 100% with that of the chicken ovalbumin DNA sequences from the GenBank database. We also found that the presence of the MCP-3 encoding plasmid in STM1 or E. coli DH1 could increase the recovery of both STM1 and E. coli DH1 over those that carry the empty plasmids. Antigen presentation assay also indicates that MCP-3 can positively influence the presentation of ovalbumin. Conclusion: the infection of DCs by STM1-carrying DNA vaccine and MCP-3 results in an increase of processing and presentation of ovalbumin in vitro. Keywords : DNA vaccine, MCP-3, APC, Salmonella, Dendritic cell

Ferrets exclusively synthesize Neu5Ac and express naturally humanized influenza A virus receptors

Mammals express the sialic acids ​N-acetylneuraminic acid (​Neu5Ac) and ​N-glycolylneuraminic acid (​Neu5Gc) on cell surfaces, where they act as receptors for pathogens, including influenza A virus (IAV). ​Neu5Gc is synthesized from ​Neu5Ac by the enzyme cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH). In humans, this enzyme is inactive and only ​Neu5Ac is produced. Ferrets are susceptible to human-adapted IAV strains and have been the dominant animal model for IAV studies. Here we show that ferrets, like humans, do not synthesize ​Neu5Gc. Genomic analysis reveals an ancient, nine-exon deletion in the ferret CMAH gene that is shared by the Pinnipedia and Musteloidia members of the Carnivora. Interactions between two human strains of IAV with the sialyllactose receptor (sialic acid—α2,6Gal) confirm that the type of terminal sialic acid contributes significantly to IAV receptor specificity. Our results indicate that exclusive expression of ​Neu5Ac contributes to the susceptibility of ferrets to human-adapted IAV strains

Biological Effects of a De Novo Designed Myxoma Virus Peptide Analogue: Evaluation of Cytotoxicity on Tumor Cells

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Determinants of mortality in non-neutropenic ICU patients with candidaemia

Introduction: Candidaemia in critically-ill intensive care unit (ICU) patients is associated with high crude mortality. Determinants of mortality – particularly those amenable to potential modification – are incompletely defined. Methods: A nationwide prospective clinical and microbiological cohort study of all episodes of ICU-acquired candidaemia occurring in non-neutropenic adults was undertaken in Australian ICUs between 2001 and 2004. Multivariate Cox regression analyses were performed to determine independently significant variables associated with mortality. Results: 183 episodes of ICU-acquired candidaemia occurred in 183 patients during the study period. Of the 179 with microbiological data, Candida albicans accounted for 111 (62%) episodes and Candida glabrata, 32 (18%). Outcome data were available for 173: crude hospital mortality at 30 days was 56%. Host factors (older age, ICU admission diagnosis, mechanical ventilation and ICU admission diagnosis) and failure to receive systemic antifungal therapy were significantly associated with mortality on multivariate analysis. Among the subset who received initial fluconazole therapy (n = 93), the crude mortality was 52%. Host factors (increasing age and haemodialysis receipt), but not organism- (Candida species, fluconazole MIC), pharmacokinetic- (fluconazole dose, time to initiation), or pharmacodynamic-related parameters (fluconazole dose:MIC ratio) were associated with mortality. Process of care measures advocated in recent guidelines were implemented inconsistently: follow-up blood cultures were obtained in 68% of patients, central venous catheters removed within five days in 80% and ophthalmological examination performed in 36%. Conclusions: Crude mortality remains high in Australian ICU patients with candidaemia and is overwhelmingly related to host factors but not treatment variables (the time to initiation of antifungals or fluconazole pharmacokinetic and pharmacodynamic factors). The role and timing of early antifungal intervention in critically-ill ICU patients requires further investigation.Deborah J.E. Marriott, E. Geoffrey Playford, Sharon Chen, Monica Slavin, Quoc Nguyen, David Ellis and Tania C. Sorrell for the Australian Candidaemia Stud

An evaluation of the immunogenicity and protective responses to Brachyspira hyodysenteriae recombinant SmpB vaccination

SmpB is an outer membrane protein of Brachyspira hyodysentariae that is present in some strains of the bacterium. It shares the same locus as SmpA, but all strains tested to date contain either one protein or the other, never both. In this study we have evaluated the efficacy of vaccination with SmpB to elicit immune responses in mice and to protect against a subsequent challenge. Immunised mice develop humoral and cellular responses to SmpB delivered as either a DNA vaccine or a recombinant protein, although the magnitude of the responses is greater after protein vaccination. The responses induced after protein vaccination offer moderate protection against disease and indicate that SmpB has potential as a component of a vaccine against B. hyodysentariae