Death Receptor Signaling During E. Coli And Salmonella Infection
Funder
National Health and Medical Research Council
Funding Amount
$586,076.00
Summary
Upon encountering invading microorganisms, the body’s immune system usually initiates an inflammatory response to recruit populations of immune cells to the site of infection. To counter this attack, many bacterial pathogens have evolved distinct ways of disarming the inflammatory response. We are investigating the discovery that gastrointestinal bacteria such as Salmonella and pathogenic E. coli specifically interfere with the messages sent by the body’s innate sensors to recruit killer immune ....Upon encountering invading microorganisms, the body’s immune system usually initiates an inflammatory response to recruit populations of immune cells to the site of infection. To counter this attack, many bacterial pathogens have evolved distinct ways of disarming the inflammatory response. We are investigating the discovery that gastrointestinal bacteria such as Salmonella and pathogenic E. coli specifically interfere with the messages sent by the body’s innate sensors to recruit killer immune cells.Read moreRead less
Shigella Flexneri O Antigen Polysaccharides: Biosynthesis, Function In Virulence, And Interaction With IcsA/VirG
Funder
National Health and Medical Research Council
Funding Amount
$468,055.00
Summary
Shigella flexneri bacteria cause dysentery in millions of humans each year. The bacterium invades and replicates within the cells of the large intestine. Inside cells, S. flexneri is able to use the host cell's actin-based motility machinery to become motile within the cells, and this can be seen as F-actin comet tails extending from one end of the cell. Bacterial cell surface components residing in the outer membrane are important for the bacterium's ability to cause disease. Two of these compo ....Shigella flexneri bacteria cause dysentery in millions of humans each year. The bacterium invades and replicates within the cells of the large intestine. Inside cells, S. flexneri is able to use the host cell's actin-based motility machinery to become motile within the cells, and this can be seen as F-actin comet tails extending from one end of the cell. Bacterial cell surface components residing in the outer membrane are important for the bacterium's ability to cause disease. Two of these components (lipopolysaccharides (LPS) and their polysaccharide chains (O antigens), and IcsA-VirG protein)) are required for initiating actin polymerisation, and mutations affecting synthesis of these components reduce ability to cause disease. In previous studies we have found that O antigen and the synthesis and function of IcsA are interrelated. This project will study how the O antigens are synthesised and their chain length determined by the Wzz protein, and the Wzz structure in relation to its function will also be characterised. The role played by O antigen in intracellular motility will be studied to determine the mechanisms involved. Infection of cells and cell free extracts, antibodies, and an enzyme which specifically degrades the O antigen, will be used to study how O antigen affect the interaction between bacteria with human cell proteins. The relationship between O antigen and IcsA function will be studied using monoclonal antibodies raised to IcsA. The effect of LPS on the outer membrane protease IcsP will be investigated, as will the effect of LPS lipid A mutations on O antigen and virulence. These studies will contribute to a better understanding of the biosynthesis of an ubiquitous bacterial cell surface component (O antigen), its function as a virulence factor in bacterial interactions with host cells. This may lead to novel therapeutic strategies to prevent and control Shigellosis and other bacterial infections.Read moreRead less
Diabolic Regulation Of Macrophage Cell Death Pathways By Legionella
Funder
National Health and Medical Research Council
Funding Amount
$616,912.00
Summary
The bacterial pathogen Legionella causes fatal pneumonia in immuno-compromised humans. Infections depend on a sophisticated secretion machinery that translocates hundreds of proteins into host cells. These proteins subvert several essential defense pathways, including cell death signals. This project will highlight how Legionella interfere with cell death pathways and control the survival of its host cells. These findings will facilitate the development of promising new anti-bacterial agents.
The Bacterial Type IX Secretion System In Polymicrobial Dysbiosis And Chronic Inflammation
Funder
National Health and Medical Research Council
Funding Amount
$1,900,000.00
Summary
Periodontitis (severe gum disease) affects 1 in 3 adults and has been linked with heart attacks, cancer and dementia. I will lead a multidisciplinary team investigating the interaction between disease causing bacteria in the mouth and the immune response which results in destruction of the tooth’s supporting tissues and allows bacteria to enter the blood stream. The expected outcome is the development of a novel therapy which will stop progression of disease associated with these pathogens.
Analysis And Regulation Of Leptospiral Virulence Factors.
Funder
National Health and Medical Research Council
Funding Amount
$630,465.00
Summary
Leptospirosis is a globally important infectious disease caused by Leptospira spp. This project aims to identify and characterise factors which play a role in disease development by knocking out genes, then investigating the impact on overall gene-protein expression in the mutant strain and its ability to cause disease. This will allow us to gain insights on mechanisms by which Leptospira spp. cause disease, leading to development of better methods of disease control and prevention.