Novel mechanisms of bacterial arsenic metabolism - arsenate reduction and arsenite oxidation. Novel arsenic metabolising bacteria (i.e., arsenate respiring and arsenite oxidising), which are both phylogenetically and physiologically unique, have been isolated from arsenic-contaminated areas in Australia. The arsenate respiring bacterium, Chrysiogenes arsenatis, is of particular interest as it is the only organism reported able to respire with arsenate using the respiratory substrate acetate as t ....Novel mechanisms of bacterial arsenic metabolism - arsenate reduction and arsenite oxidation. Novel arsenic metabolising bacteria (i.e., arsenate respiring and arsenite oxidising), which are both phylogenetically and physiologically unique, have been isolated from arsenic-contaminated areas in Australia. The arsenate respiring bacterium, Chrysiogenes arsenatis, is of particular interest as it is the only organism reported able to respire with arsenate using the respiratory substrate acetate as the electron donor. It is proposed that physiological, biochemical and molecular biological studies be carried out to better understand the mechanisms by which these organisms metabolise arsenic. The knowledge gained from these studies will have worldwide application in the development of an arsenic bioremediation system.Read moreRead less
Feasting on protein? Strategies of organic nitrogen acquisition by plant roots. Crops require large amounts of nitrogen for growth. Application of nitrogen fertiliser enhances yield, but causes off-site nitrogen pollution, a main threat to ecosystem integrity. Most nitrogen in soil occurs as organic complexes that are broken down by soil organism into small compounds, which are taken up roots or lost from the soil. This project will generate fundamental knowledge of how an Australian species and ....Feasting on protein? Strategies of organic nitrogen acquisition by plant roots. Crops require large amounts of nitrogen for growth. Application of nitrogen fertiliser enhances yield, but causes off-site nitrogen pollution, a main threat to ecosystem integrity. Most nitrogen in soil occurs as organic complexes that are broken down by soil organism into small compounds, which are taken up roots or lost from the soil. This project will generate fundamental knowledge of how an Australian species and a crop species with unusual root specialisations access soil organic nitrogen, thus increasing the efficiency of nitrogen use and reducing nitrogen loss. The research employs cutting-edge techniques for sustainable resource use, improved efficiency of crops and farming systems, and preservation of Australia's biodiversity.Read moreRead less
Structural Investigation Into The Regulation Of The Colony Stimulating Factor Receptor, C-FMS.
Funder
National Health and Medical Research Council
Funding Amount
$287,321.00
Summary
The colony stimulating factor receptor, c-FMS is a member of a family of protein signalling molecules expressed on the cell surface that are implicated in the development of serious diseases in humans, such as inflammatory diseases and cancer. A number of important proteins bind to and regulate c-FMS in different ways. I intend to visualise these interactions to further understand how c-FMS activity is controlled by alternative means.
A Unique Target in the Purine Biosynthesis of the Pathogen Helicobacter pylori. The uptake systems of purine and analogues of the human pathogen Helicobacter pylori will be characterised because they can be utilised to introduce cytotoxic compounds into the cells. The first step in de novo purine biosynthesis of the bacterium is catalysed by two different enzymes, which are components of other biosynthetic pathways. These unique properties make them excellent potential therapeutic targets. Their ....A Unique Target in the Purine Biosynthesis of the Pathogen Helicobacter pylori. The uptake systems of purine and analogues of the human pathogen Helicobacter pylori will be characterised because they can be utilised to introduce cytotoxic compounds into the cells. The first step in de novo purine biosynthesis of the bacterium is catalysed by two different enzymes, which are components of other biosynthetic pathways. These unique properties make them excellent potential therapeutic targets. Their individual combined activities in purine biosynthesis will be characterised in situ and in vitro. Isogenic mutants with inactivated genes encoding for these enzymes will be constructed to investigate their role in the survival of the organism.Read moreRead less
Cellular Responses to Adversity: Oxidative Stress and Protection Against Oxidative Damage. A deficiency in the protein haem oxygenase-1 causes severe biological consequences in animals and humans. These include decreased reproduction, retarded development, the inability of the body to handle iron, chronic inflammation and increased susceptibility to age-associated diseases. This study will determine how a deficiency of the protein alters cells at the level of genes, proteins and protein function ....Cellular Responses to Adversity: Oxidative Stress and Protection Against Oxidative Damage. A deficiency in the protein haem oxygenase-1 causes severe biological consequences in animals and humans. These include decreased reproduction, retarded development, the inability of the body to handle iron, chronic inflammation and increased susceptibility to age-associated diseases. This study will determine how a deficiency of the protein alters cells at the level of genes, proteins and protein functions. By doing so, the project will illuminate how haem oxygenase-1 alters cell functions in a beneficial way. This information will eventually assist in preventing the serious disorders associated with deficiency of haem oxygenase-1. It will also provide the basis for novel treatments to slow down age-associated diseases.Read moreRead less
Biosynthesis of nonribosomal peptide toxins in cyanobacteria: A functional characterisation of microcystin synthetase. Microcystins are potent toxins and tumour promoters produced by cyanobacteria associated with blue-green algal blooms. This non-ribosomal peptide is produced by microcystin synthetase, a unique enzyme complex comprised of peptide synthetases, polyketide synthases, and integrated accessory enzymes. We have identified and characterised the extensive gene cluster encoding this enzy ....Biosynthesis of nonribosomal peptide toxins in cyanobacteria: A functional characterisation of microcystin synthetase. Microcystins are potent toxins and tumour promoters produced by cyanobacteria associated with blue-green algal blooms. This non-ribosomal peptide is produced by microcystin synthetase, a unique enzyme complex comprised of peptide synthetases, polyketide synthases, and integrated accessory enzymes. We have identified and characterised the extensive gene cluster encoding this enzyme. This project describes the biochemical characterisation of specific enzyme activities within microcystin synthetase and how they determine the final structure and toxicity of the many forms of microcystin. Interactions between this enzyme complex and its substrate amino acids will provide information for the genetic engineering of this and similar natural products.Read moreRead less
Regulation Of The Cardiovascular Disease-Associated Protease Inhibitor Cystatin C For Therapeutic Application
Funder
National Health and Medical Research Council
Funding Amount
$498,505.00
Summary
Proteases can contribute to atherosclerosis, so they are normally controlled by the endogenous inhibitor, Cystatin C (Cst C). Some conditions cause reduction in Cst C levels and hence disease. On the other hand, excess Cst C can form toxic aggregates. In this project, we will identify mechanisms controlling Cst C expression and aggregation to find therapeutic strategies to treat cardiovascular diseases associated with Cst C.
Regulation Of Synthesis, Dimerisation And Secretion Of The Amyloidogenic Protease Inhibitor Cystatin C
Funder
National Health and Medical Research Council
Funding Amount
$423,565.00
Summary
The cells that compose our tissues are embedded in a complex mesh of extracellular proteins (for example collagen) that provide support, strenght and elasticity to the tissues. This extracellular matrix is not static; it is constantly remodelled when, for example, the cells of the immune system move through interstitial spaces to monitor the healthiness of the tissues. When infections or injuries occur, the inflammatory reactions that develop, and the processes involved in tissue repair, also in ....The cells that compose our tissues are embedded in a complex mesh of extracellular proteins (for example collagen) that provide support, strenght and elasticity to the tissues. This extracellular matrix is not static; it is constantly remodelled when, for example, the cells of the immune system move through interstitial spaces to monitor the healthiness of the tissues. When infections or injuries occur, the inflammatory reactions that develop, and the processes involved in tissue repair, also involve profound changes in the composition of the extracellular matrix. Such processes are also important for tumour growth; the cancer cells need to clear their way through interstitial space to escape to circulation and metastasize. During all these processes, the cells release to the extracellular space proteases that degrade collagen and the other components of the extracellular matrix. Obviously, these proteases must be tightly regulated to prevent them running out of control, so the cells also produce inhibitors of the proteases. The amount of proteases and inhibitors contained in the extracellular space must be maintained properly. If this equilibrium is disrupted, this can lead to pathology For instance, atherosclerosis is caused in part by excessive proteolysis of the blood vessel wall. In this project we want to study the mechanisms of one of the most abundant and important inhibitors of extracellular proteolysis: Cystatin C. We have discovered that certain cells of the immune system called dendritic cells posses interesting mechanisms to regulate how much Cystatin C they secrete. Furthermore, one of this mechanisms, which consists of pairing the protein to produce inactive dimers, may be the cause of some diseases characterised by accumulation of Cystatin C in the extracellular space. Our study may allow us to design therapies for the treatment of pathologies associated with defective or excessive production of Cystatin C.Read moreRead less
Characterisation of the oxygen-sensing asparaginyl hydroxylase, FIH-1, and hydroxylase-specific antagonists. This research will provide fundamental information on how cells and whole organisms can sense and respond accordingly to oxygen deficiency. This information is fundamental for our understanding of embryo development and adult life in different environments, and central to the diagnosis and treatment of diseases such as stroke, cardiovascular disease, and cancer. This research will contrib ....Characterisation of the oxygen-sensing asparaginyl hydroxylase, FIH-1, and hydroxylase-specific antagonists. This research will provide fundamental information on how cells and whole organisms can sense and respond accordingly to oxygen deficiency. This information is fundamental for our understanding of embryo development and adult life in different environments, and central to the diagnosis and treatment of diseases such as stroke, cardiovascular disease, and cancer. This research will contribute to our basic knowledge of these processes, provide invaluable information about the specific genes and proteins involved, and provide direct information about the therapeutic potential of specific drugs or inhibitors designed to target this oxygen response in human disease.Read moreRead less
The Biosynthesis Of Mycobactin T, A Virulence Factor From Mycobacterium Tuberculosis.
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
Mycobacterium tuberculosis is the causative agent of tuberculosis. The drug isoniazid led to a dramatic and sustained decline in mortality due to tuberculosis. This led to it being described in medical literature in 1988 as a disappearing disease which was now fairly easy to treat. However, the advent of HIV and the rapid rise of multidrug resistant M. tuberculosis led to dramatic changes. The risk that an HIV infected individual will develop active tuberculosis is 7% per year, compared to a lif ....Mycobacterium tuberculosis is the causative agent of tuberculosis. The drug isoniazid led to a dramatic and sustained decline in mortality due to tuberculosis. This led to it being described in medical literature in 1988 as a disappearing disease which was now fairly easy to treat. However, the advent of HIV and the rapid rise of multidrug resistant M. tuberculosis led to dramatic changes. The risk that an HIV infected individual will develop active tuberculosis is 7% per year, compared to a lifetime risk of 10% for an immunocompetent person. Similarly, the prevalence of drug resistant strains of M. tuberculosis is over 5% in many regions, including SE asia. Mycobacterial infections are regarded as the leading cause of morbidity and mortality world wide and WHO estimates that 30 million deaths will occur in the next decade due to these infections. Clearly, new drugs are required to combat the rising menace of this organism. The aim of this project is to detail the unique metabolic pathways in M. tuberculosis that produce Mycobactin T, essential to the virulence of this organism. Mycobactin T helps the bacteria obtain iron, an essential nutrient. These factors make the mycobaction pathway an ideal drug target and an understanding of its biochemistry is essential to its eventual exploitation for intervention in M. tuberculosis infections. We hypothesise that it may already provide the unknown site of action of a clinically employed, antituberculosis drug para-aminosalicylate (PAS). This project will i) fully define the structure of mycobactin T; ii) clone and overexpress key genes which catalyse the first three steps of mycobactin formation; iii) purify and characterise the overexpressed proteins with respect to their biochemical function; iv) examine the interaction of PAS with the proteins likely to be targeted by this antimycobacterial agent. The results of this work will provide the basis for the development of future anti-tuberculosis drugs.Read moreRead less