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
Regulatory Networks Controlling The Interaction Of Neisseria Gonorrhoeae With The Human Host
Funder
National Health and Medical Research Council
Funding Amount
$361,091.00
Summary
What does Neisseria gonorrhoeae switch on when entering a human cell? Neisseria gonorrhoeae is the causative agent of the sexually transmitted disease (STD) gonorrhoea and globally causes approximately 20-60 million new cases per annum (WHO). Gonococcal infection is the leading cause of pelvic inflammatory disease in women and ~ one third of patients will become infertile. Increased levels of resistance to traditional antibiotics have raised concerns for future treatment options. To date no succ ....What does Neisseria gonorrhoeae switch on when entering a human cell? Neisseria gonorrhoeae is the causative agent of the sexually transmitted disease (STD) gonorrhoea and globally causes approximately 20-60 million new cases per annum (WHO). Gonococcal infection is the leading cause of pelvic inflammatory disease in women and ~ one third of patients will become infertile. Increased levels of resistance to traditional antibiotics have raised concerns for future treatment options. To date no successful vaccine strategies have been developed for this organism, primarily because the cell surface proteins elicit limited immunological protection against other strains. To enable the development of innovative approaches to the control of gonococcal infections, we propose to investigate the regulatory networks in gonococci that are important for initial colonization and survival in the human host. We will examine the role of a class of proteins, called sigma factors, that control the expression of a large number of genes in a concerted fashion. The sigma factors themselves do not recognize environmental signals, but their activity is controlled by a complicated array of proteins that are responsive to changing conditions in the bacterial cell. We have for the first time in any bacterial pathogen, identified all of the genes controlled by sigma factors in the obligate human pathogen, Neisseria gonorrhoeae. We have also found that the mechanisms controlling the activity of the sigma factors in this organism are different to those found in other bacterial pathogens. Our aim is to understand the mechanisms that control sigma factors and to gain insight into how N. gonorrhoeae sense and responds to the host cell during infections.Read moreRead less
Transposable Element Mobility And Chromosomal Rearrangement In The Fungal Pathogen Cryptococcus During Human Infection
Funder
National Health and Medical Research Council
Funding Amount
$322,028.00
Summary
Pathogenic fungi present in the environment have emerged as an increasingly common threat to human health. Cryptococcus neoformans and the closely related species Cryptococcus gattii are the leading causes of life-threatening fungal meningitis, and Australia is one of the few countries where both species are prevalent. Although C. neoformans is an increasingly common cause of infection in immunocompromised patients such as those suffering from AIDS, approximately one in four infected individuals ....Pathogenic fungi present in the environment have emerged as an increasingly common threat to human health. Cryptococcus neoformans and the closely related species Cryptococcus gattii are the leading causes of life-threatening fungal meningitis, and Australia is one of the few countries where both species are prevalent. Although C. neoformans is an increasingly common cause of infection in immunocompromised patients such as those suffering from AIDS, approximately one in four infected individuals has no apparent immune system defect. For patients with AIDS, in the absence of antiretroviral therapy cryptococcal infection is incurable and requires lifelong treatment with antifungal medication to keep the infection in check. During infection, Cryptococcus is under tremendous stress enforced not only by the immune system and the presence of antifungals, but also by the high temperature, nutrient limiting environment encountered in the host. The proposed research will reveal how Cryptococcus evolves in this environment to enable persistence of infection despite medical intervention. I propose that naturally occurring mobile genetic elements present in the Cryptococcus genome cause chromosomal rearrangements during long term infection to produce gene deletions and duplications that facilitate survival. By characterising these changes and the genes associated with them, the research will identify novel genes involved in pathogenesis and will increase our understanding of the infection process. The expected outcome of this project is a detailed understanding of the roles mobile element movement and chromosomal rearrangement play in Cryptococcus during infection, and how these affect genes that contribute to the pathogenic process. The fundamental knowledge gained from this study will facilitate studies designed to combat infections in the clinical setting, provide new drug targets and help foster the development of more effective therapies.Read moreRead less
The diversity of HIV quasispecies within a single AIDS patient is far greater than the global diversity of influeneza annually, highlighting the enormous burden HIV imposes on the immune network. The capacity of HIV-1 to evolve quickly has significantly impaired our effort to produce effective vaccine and long lasting treatment strategy. This project utilizes multidisciplinary approaches to delineate determinants that drives the diversification of HIV-1.
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
Viral Factors Contributing To Flavivirus-induced Cell Death And Pathogenicity
Funder
National Health and Medical Research Council
Funding Amount
$612,885.00
Summary
West Nile virus is a mosquito-transmitted pathogen that causes severe and fatal neurological disease in humans. There are currently no effective treatments or vaccines for this disease. In this project, we will investigate how West Nile virus and other viruses of the same group use a novel translational regulatory mechanism to modulate the host antiviral response and facilitate viral pathogenicity. This will provide valuable information for the development of effective treatments against this me ....West Nile virus is a mosquito-transmitted pathogen that causes severe and fatal neurological disease in humans. There are currently no effective treatments or vaccines for this disease. In this project, we will investigate how West Nile virus and other viruses of the same group use a novel translational regulatory mechanism to modulate the host antiviral response and facilitate viral pathogenicity. This will provide valuable information for the development of effective treatments against this medically important group of viral pathogens.Read moreRead less
Molecular Characterization Of E. Coli That Cause Urinary Tract Infection
Funder
National Health and Medical Research Council
Funding Amount
$387,114.00
Summary
The long term goals of the proposed research are to understand the processes by which uropathogenic Escherichia coli (UPEC) cause acute, recurrent and chronic infections and to identify new UPEC targets for therapeutic intervention. Urinary tract infections (UTI) are among the most common infectious diseases of humans and a major cause of morbidity and mortality. In the USA, UTI accounts for more than 1 million hospitalizations and $1.6 billion in medical expenditures each year. It is estimated ....The long term goals of the proposed research are to understand the processes by which uropathogenic Escherichia coli (UPEC) cause acute, recurrent and chronic infections and to identify new UPEC targets for therapeutic intervention. Urinary tract infections (UTI) are among the most common infectious diseases of humans and a major cause of morbidity and mortality. In the USA, UTI accounts for more than 1 million hospitalizations and $1.6 billion in medical expenditures each year. It is estimated that one in four women and one in twenty men will develop a UTI in their lifetime. The recurrence rate is high and no treatment other than antibiotics (often inefficient) is currently available. UPEC are the primary cause of UTI. In the last grant period, we focused on the molecular interplay that exists between different surface adhesins of UPEC. We succeeded in demonstrating functional interference between adhesins, motility organelles, aggregation factors and the capsule. We also discovered and partially characterized several novel UPEC adhesins that may play a role in pathogenesis. We established two novel technology sets: a mouse model of ascending UTI and the flow chamber biofilm model. In the next grant period, we will build on these concepts and experimental systems to gain a deeper understanding of the molecular mechanisms underlying UPEC virulence. We will characterize the role of several novel UPEC surface proteins in cell adhesin, aggregation, biofilm formation and colonization of the mouse urinary tract. We will employ an integrated approach that combines a powerful bacterial genetic system, a biofilm model, a mouse UTI model, microscopy and tissue culture systems to reveal the cellular, molecular, and structural basis for the pathogenesis of UTI. The work will facilitate the development of new vaccine approaches to prevent UTI, such as novel mechanisms for strain attenuation and vaccine design. The burden of UTI disease demands such research endeavours.Read moreRead less
Pathogenesis Of Infections With Yersinia Enterocolitica
Funder
National Health and Medical Research Council
Funding Amount
$339,634.00
Summary
Yersinia enterocolitica is a significant cause of food-poisoning, gastroenteritis and abdominal pain which may be mistaken for acute appendicitis. Y. enterocolitica is a heterogenous bacterial species only some strains of which are able to cause disease. Many of the disease-causing strains have readily identifiable virulence determinants which facilitate their detection in clinical microbiological laboratories. By contrast, other types, in particular the biotype 1A strains, lack these determinan ....Yersinia enterocolitica is a significant cause of food-poisoning, gastroenteritis and abdominal pain which may be mistaken for acute appendicitis. Y. enterocolitica is a heterogenous bacterial species only some strains of which are able to cause disease. Many of the disease-causing strains have readily identifiable virulence determinants which facilitate their detection in clinical microbiological laboratories. By contrast, other types, in particular the biotype 1A strains, lack these determinants, although many of them are significantly associated with disease. During the past few years, we have compared biotype 1A strains of Y. enterocolitica obtained from patients with those from non-clinical sources in a number of assays for virulence-associated properties. These studies have shown that clinical isolates differ from non-clinical ones in terms of their ability to (1) invade epithelial cells in vitro and intestinal absorptive cells in vivo, (2) escape from epithelial cells and macrophages they have invaded, (3) resist killing by macrophages, and (4) colonise the intestinal tracts of mice. The aim of the study is to identify the bacterial determinants responsible for these differences between clinical and non-clinical strains of Y. enterocolitica biotype 1A. This will be achieved by using genetic techniques to modify virulent strains of biotype 1A at random and then identify derivatives of these bacteria with altered virulence properties. We shall also use genetic techniques to identify genes that are specifically activated when the bacteria come into contact with animal cells and tissues. The results of this research will provide new insights into the virulence mechanisms of Y. enterocolitica and related bacteria, and will be used to develop diagnostic tests which will allow pathogenic strains to be distinguished from harmless ones.Read moreRead less
Urinary tract infections (UTI) are among the most common infectious diseases of humans and a major cause of morbidity and mortality. In the USA, UTI accounts for >$1.6 billion in medical expenses each year. It is estimated that 50% of women will develop a UTI in their lifetime. This research aims to understand the processes by which bacteria colonize the human bladder. The work has implications for the development of new approaches to prevent and treat UTI.
The Impact Of Influenza A Virus PB1-F2 Protein On Host Immunity And The Potential For Therapeutic Targeting
Funder
National Health and Medical Research Council
Funding Amount
$317,076.00
Summary
The 1918 influenza virus pandemic resulted in 50 million deaths globally and there is potential for new pandemics, such as the predicted H5N1 Bird Flu . Exact causes of such devastating lethality are not fully identified. Newly discovered influenza A virus (IAV) PB1-F2 protein is present in nearly all highly pathogenic IAVs and promotes virus virulence. This study will further examine the way in which PB1-F2 impacts the host, revealing potential therapeutic targets to lessen disease burden.