Molecular Mechanisms Of Persistence Of Mycobacterium Tuberculosis
Funder
National Health and Medical Research Council
Funding Amount
$398,142.00
Summary
Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB. It infects about third of all people in the world and kills several million people each year. People with active TB spread the mycobacteria in aerosols from their breath. When another person inhales an infected aerosol the mycobacteria enter their lungs and establish a new infection. During the course of infection M. tuberculosis is exposed to a variety of harsh environments inside the lungs which normally kill other bacte ....Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB. It infects about third of all people in the world and kills several million people each year. People with active TB spread the mycobacteria in aerosols from their breath. When another person inhales an infected aerosol the mycobacteria enter their lungs and establish a new infection. During the course of infection M. tuberculosis is exposed to a variety of harsh environments inside the lungs which normally kill other bacteria. M. tuberculosis is able to survive and adapt to those harsh environments. M. tuberculosis has an especially thick and tough cell wall which protects it. M. tuberculosis can adapt to the environments it encounters in a patient by changing their cell walls. The wall also protects mycobacteria from chemicals so it is resistant to many common antibiotics. There are some drugs to treat TB however M. tuberculosis is building up resistance to those drugs so we need to find new ones We will determine how mycobacteria synthesize their special cell wall and how they adapt during an infection. If we know how the details of how M. tuberculosis protects itself then we can find potential weakness which could be targets for the development of new drugs to treat TB.Read moreRead less
Dissemination And Virulence Properties Of The She Pathogenicity Island Of Shigella Flexneri.
Funder
National Health and Medical Research Council
Funding Amount
$110,625.00
Summary
Bacterial species belonging to the genus Shigella are responsible for intestinal diseases ranging from mild diarrhoea to life threatening bacillary dysentery. Such diseases kill over a million people, mainly infants in developing countries, every year and lead to serious morbidity and mortality even in industrialised countries with well developed health care systems. In many cases the virulence of Shigella species is augmented by large fragments of DNA, called pathogenicity islands, that carry g ....Bacterial species belonging to the genus Shigella are responsible for intestinal diseases ranging from mild diarrhoea to life threatening bacillary dysentery. Such diseases kill over a million people, mainly infants in developing countries, every year and lead to serious morbidity and mortality even in industrialised countries with well developed health care systems. In many cases the virulence of Shigella species is augmented by large fragments of DNA, called pathogenicity islands, that carry genes which contribute to the development of disease (pathogenesis) in humans. Pathogenicity islands are important genetic elements which appear to spread independantly throughout bacterial populations and therefore contribute to the emergence of new virulence traits in bacteria. Recently, we identified two related pathogenicity islands carried by both Shigella flexneri and other species of the genus Shigella. The two pathogenicity islands belong to a unique class of genetic elements found in Shigella species and virulent strains of the intestinal bacterium E. coli. Our current study is aimed at (1) understanding the mechanisms by which one of these islands, the she pathogenicity island, spreads from one bacterial strain to another to introduce disease-producing or virulence genes to new bacteria and (2) to study how the sigA virulence gene, carried on the she pathogenicity island, contributes to disease development in humans. We know that sigA encodes a protein toxin which contributes to the loss of fluid from the intestines of rabbits that have been experimentally infected with Shigella flexneri. We propose to study the structure and function of the SigA protein to determine how it interacts with tissues to produce a pathological state. Such studies will enhance our understanding of the process of disease development and contribute to the investigation and assessment of new strategies for therapeutic intervention.Read moreRead less
GPI Anchored Forms Of The Dengue Virus NS1 Protein: Production And Role In Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$203,448.00
Summary
Dengue viruses are carried by mosquitoes and infect millions of people around the world, particularly in tropical countries of SE Asia, Central and South America, Africa and recently in Australia (North Queensland and NT). There is no vaccine or drug available for preventing or treating the infections, which are characterised by severe illness that involves inflammation and fevers that can sometimes be fatal. This study focuses on an unusual form of a dengue virus protein (called NS1) which we h ....Dengue viruses are carried by mosquitoes and infect millions of people around the world, particularly in tropical countries of SE Asia, Central and South America, Africa and recently in Australia (North Queensland and NT). There is no vaccine or drug available for preventing or treating the infections, which are characterised by severe illness that involves inflammation and fevers that can sometimes be fatal. This study focuses on an unusual form of a dengue virus protein (called NS1) which we have identified. We plan to study the role that this protein plays in the more severe and often fatal forms of dengue infection (dengue haemorrhagic fever and dengue shock syndrome). In these more severe and life threatening forms of dengue the blood vessels of these patients become leaky. It is thought that this is caused by the secretion of certain chemicals (cytokines) from infected cells. We have shown that dengue infected human cells, which have the unusual form of NS1 protein on their surface, are capable of being activated by antibodies. Antibodies are proteins which are produced by the human body to fight infection. We aim to study whether cytokines are secreted from infected human blood cells activated in this way and whether these cytokines cause blood vessels to become leaky. We will also study how the virus produces this variant form of NS1 in the two host species that the virus infects; mosquito and human. These studies will increase our understanding of dengue virus infection and will provide valuable information concerning the role that this unusual form of the degue virus protein NS1 plays in the severe forms of dengue fever; dengue haemorrhagic fever and dengue shock syndrome.Read moreRead less
Genome Wide Investigations Of Mycobacterium Tuberculosis To Reveal Processes Of Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$396,341.00
Summary
Tuberculosis remains a global health burden of staggering proportions. Around 1 in 3 people are infected with Mycobacteria tuberculosis, the organism responsible for the disease, which kills 2 million people annually. The emergence of strains now resistant to almost all of our front line drugs has placed extra pressure on researchers who are attempting to develop new protective vaccines and the critical antibiotics required to eradicate the disease. Furthermore the current global HIV pandemic is ....Tuberculosis remains a global health burden of staggering proportions. Around 1 in 3 people are infected with Mycobacteria tuberculosis, the organism responsible for the disease, which kills 2 million people annually. The emergence of strains now resistant to almost all of our front line drugs has placed extra pressure on researchers who are attempting to develop new protective vaccines and the critical antibiotics required to eradicate the disease. Furthermore the current global HIV pandemic is making the situation far worse as HIV kills the very cells of the body that protect us from tuberculosis. This research project will fill the significant gaps in our knowledge of M. tuberculosis infection, specifically identify the genes of the organism which allow it to invade and spread throughout the body. M. tuberculosis infection consists of 3 characteristic stages, i.e. colonisation, spread and long term survival in specialised structures called granulomas. It is from these granulomas that the bacterium can emerge after long periods of inactivity to cause clinical tuberculosis. Using a mouse model of infection I will define the genes needed by the bacterium to survive at these 3 key stages of disease thereby providing for a better knowledge base from which to design new vaccine strategies and to create effective drugs.Read moreRead less