Origins And Relationships Of Shigella And Enteroinvasive Escherichia Coli
Funder
National Health and Medical Research Council
Funding Amount
$377,310.00
Summary
Shigella is a well known highly infectious human pathogen with as few as 10 cells allowing effective spread by infected food or water, and also by person to person contact. Shigellosis is a particularly significant disease for children due to lack of pre-existing immunity and greater chance of transfer by fecal-oral route. One group of E. coli called Enteroinvasive E. coli (EIEC) resembles Shigella in many aspects from disease symptoms to biochemical properties. EIEC is a major cause of diarrhoe ....Shigella is a well known highly infectious human pathogen with as few as 10 cells allowing effective spread by infected food or water, and also by person to person contact. Shigellosis is a particularly significant disease for children due to lack of pre-existing immunity and greater chance of transfer by fecal-oral route. One group of E. coli called Enteroinvasive E. coli (EIEC) resembles Shigella in many aspects from disease symptoms to biochemical properties. EIEC is a major cause of diarrhoea in less developed countries and has also caused large outbreaks in developed countries. It is now clear that Shigella and E. coli are really one species. EIEC and Shigella strains are variants of E. coli with humans as the only host. However separation of the two in all records and most studies means that there is no integrated understanding of the forms. We aim to study the relationships of Shigella and EIEC and expect significant insights into the origins of Shigella-EIEC. This will facilitate diagnosis and understanding of the disease(s) and lead to a far better classification . EIEC-Shigella strains have arisen from other E. coli independently. This has happened seven times in the derivation of Shigella and we expect more such events with EIEC. An interesting phenomenon during this process is that strains tend to lose metabolic functions. In this study we will look at what, why and how functions are lost. O antigens are important in evading the host immune system. Shigella strains obtained many O antigens, the majority apparently from other species. This is quite likely the key to its success. We will look at how Shigella obtained new O antigens. This project will be significant in the understanding of Shigell-EIEC, a very significant human pathogen, and in general for understanding emergence of new pathogens.Read moreRead less
Identifying The Physiological Conditions That Promote Lateral Gene Transfer And Evolution Of New Streptococcal Pathovars
Funder
National Health and Medical Research Council
Funding Amount
$415,907.00
Summary
In the last few decades, the diseases caused by the three human pathogens, groups A, B and G streptococcus have undergone a transformation. The exchange of DNA between these species is speculated to play a role in this changing disease association. In this proposal we will identify the specific physiological and growth conditions that promote DNA transfer. Such information may help in our understanding of how new pathogenic strains of streptococci arise.
Analysis Of Rho GTPase Signalling Pathways In An Epithelial To Mesenchymal Transition During Development Of The Mesoderm
Funder
National Health and Medical Research Council
Funding Amount
$409,500.00
Summary
A critical step in the progression of cancers that are derived from epithelial tissues is a transition from an epithelial cell type to a migratory mesenchymal cell type that can spread to other parts of the body. This change in cell behaviour also occurs, apparently by a similar mechanism, during the development of some normal tissue types. Here we propose to use an animal model of this process, coupled with advanced molecular genetic and cell biological techniques, to investigate a newly discov ....A critical step in the progression of cancers that are derived from epithelial tissues is a transition from an epithelial cell type to a migratory mesenchymal cell type that can spread to other parts of the body. This change in cell behaviour also occurs, apparently by a similar mechanism, during the development of some normal tissue types. Here we propose to use an animal model of this process, coupled with advanced molecular genetic and cell biological techniques, to investigate a newly discovered cell signalling mechanism required for the transition of cells from an epithelial form to a mesenchymal form. Understanding the molecular steps in this new pathway and discovering new genes involved will provide tools for understanding and preventing the metastasis of cancer cells.Read moreRead less
Conditional Knockout Of The Murine Patched Gene For The Study Of Skin Differentiation And Cancer.
Funder
National Health and Medical Research Council
Funding Amount
$423,564.00
Summary
Basal cell carcinoma (BCC) is the most common cancer in Australia. We recently isolated the BCC gene, Patched (PTCH) from analysis of patients with Naevoid Basal Cell Carcinoma Syndrome (NBCCS). Individuals with NBCCS have a wide variety of developmental defects in addition to a cancer predisposition which includes medulloblastoma, rhabdomyosarcoma and ovarian fibroma as well as multiple BCCs. This application proposes the generation of an animal model for skin development and cancer by selectiv ....Basal cell carcinoma (BCC) is the most common cancer in Australia. We recently isolated the BCC gene, Patched (PTCH) from analysis of patients with Naevoid Basal Cell Carcinoma Syndrome (NBCCS). Individuals with NBCCS have a wide variety of developmental defects in addition to a cancer predisposition which includes medulloblastoma, rhabdomyosarcoma and ovarian fibroma as well as multiple BCCs. This application proposes the generation of an animal model for skin development and cancer by selectively removing patched gene function from specific cell of the skin. In doing this we will be able to determine the exact role of this gene in skin development, and how mutation causes common skin cancer.Read moreRead less
Characterization Of Neutralizing Antibody Responses In HCV Infected Individuals.
Funder
National Health and Medical Research Council
Funding Amount
$478,076.00
Summary
Hepatitis C virus is a major human pathogen infecting 200 million people world-wide. Currently, there is no vaccine to prevent infection and treatment regimes are only partially effective. IInitial HCV infection is frequently asymptomatic and 30% of people spontaneously clear the virus. The remaining 70% of people develop a life-long chronic infection that causes progressive liver disease, cirrhosis and in some cases liver cancer. The reason why some people are able to clear virus has been attri ....Hepatitis C virus is a major human pathogen infecting 200 million people world-wide. Currently, there is no vaccine to prevent infection and treatment regimes are only partially effective. IInitial HCV infection is frequently asymptomatic and 30% of people spontaneously clear the virus. The remaining 70% of people develop a life-long chronic infection that causes progressive liver disease, cirrhosis and in some cases liver cancer. The reason why some people are able to clear virus has been attributed to the development of a strong cellular immune response and antibody is belived to play a monir role in achieving viral clearance. However, measurememnt of antibody responses in HCV infected pateints is routinely performed using conventional diagnostic tests that do not measure antibody that can help neutralize and clear virus. We have developed an assay that accurately measures the level of NAb in patient sera. We have found that chronically infected patients have broadly reactive neutralizing antibodies but that patients who clear virus, naturally or through treatment do not have broadly reactive neutralizing antibodies. Possibly explaining this phenomenon is that early during infection, antibody is frequently specific only to the infecting virus therefore to detect neutralizing antibodies, homologous viral sequences must be examined. In addition, we have found evidence that HCV can evade neutralzing antibodies through masking of sites to which antibodies bind. We propose to explore whether acutely infected patients develop NAb to autologous viral sequences, and how do these viral sequences and the antibody titre change throughout the course of infection and treatment. We also plan to determine the mechanism of neutralization resistance through the use of mutagenesis of resistant HCV glycoproteins. These studies are aimed at gaining a thorough understanding of the true role of antibody in HCV infection and its influence on viral evolution.Read moreRead less
How Do P75 And Sortilin Facilitate TrkA-mediated Survival Signalling?
Funder
National Health and Medical Research Council
Funding Amount
$559,354.00
Summary
Neurotrophins are the classical growth factors that regulate neuronal survival and death throughout the nervous system in both the developing and adult animal. These factors signal through one of three receptors, but precisely how the receptors interact to propagate cell survival is unclear. The goal of this grant is to unravel the molecular basis underpinning this life and death signalling decision so that we can then devise ways to promote cell survival in neurodegenerative conditions
Structure, Formation And Evolution Of Multiple Antibiotic And Mercury Resistance Regions In Gram-negative Bacteria
Funder
National Health and Medical Research Council
Funding Amount
$550,500.00
Summary
Antibiotic resistance and particularly resistance to several different antibiotics simultaneously is becoming alarmingly common in bacteria that cause infectious diseases in humans and animals. New antibiotics are proving slow to appear and the most obvious way to increase the effectiveness and the useful lifetime of existing antibiotics is though attempting to reduce the prevalence of resistant bacteria. This can only be done using good surveillance that allows the places where resistant bacter ....Antibiotic resistance and particularly resistance to several different antibiotics simultaneously is becoming alarmingly common in bacteria that cause infectious diseases in humans and animals. New antibiotics are proving slow to appear and the most obvious way to increase the effectiveness and the useful lifetime of existing antibiotics is though attempting to reduce the prevalence of resistant bacteria. This can only be done using good surveillance that allows the places where resistant bacteria and resistance genes are present in large numbers, e.g. in food-production animals, in hospitals, in the human gut or in the environment, to be identified. Very little data of this type is available internationally and even less for the Australian situation. Using recent knowledge of resistance genes and modern molecular techniques the work will identify which resistance genes and combinations of resistance genes confering resistance to antibbiotics used either in the clinic or administered to food-producing animals or both are found in Australian isolates. By examining multiply antibiotic resistant isolates from these two and other sources the flow of resistance genes and resistant bacteria between these two reservoirs will be tracked accurately. This will allow the sources relevant to difficult to treat or untreatable infections acquired in the hospital setting to be identified and appropriate action taken.Read moreRead less
The Downstream Targets Of Patched/Hedgehog Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$423,055.00
Summary
The patched-hedgehog gene pathway is disturbed in common human cancer, including basal cell carcinoma of the skin, medulloblastoma, rhabdomyosarcoma and ovarian fibroma. This application proposes to look at the genes turned off and on by the patched gene. By identifying these genes and examining their function we will identify the exact genetic disturbance which results in a large proportion of common human cancer. Once we find these genes this opens up the possibilities of designing drugs which ....The patched-hedgehog gene pathway is disturbed in common human cancer, including basal cell carcinoma of the skin, medulloblastoma, rhabdomyosarcoma and ovarian fibroma. This application proposes to look at the genes turned off and on by the patched gene. By identifying these genes and examining their function we will identify the exact genetic disturbance which results in a large proportion of common human cancer. Once we find these genes this opens up the possibilities of designing drugs which specifically block the action of the geneticdefect and thereby treating the tumours.Read moreRead less
Genetic Variation And Host-parasite Interactions Of Sarcoptes Scabiei
Funder
National Health and Medical Research Council
Funding Amount
$294,536.00
Summary
Scabies is a disease of skin caused by the burrowing of the 'itch' mite Sarcoptes scabiei. Although up to 45 different host species can be infested by this mite, this organism is currently classified as a single species existing as multiple strains or varieties. Previous studies have failed to identify any structural differences between host-associated populations, suggesting a single gene pool. Our recent molecular study of scabies in people and dogs, from Aboriginal communities in the Northern ....Scabies is a disease of skin caused by the burrowing of the 'itch' mite Sarcoptes scabiei. Although up to 45 different host species can be infested by this mite, this organism is currently classified as a single species existing as multiple strains or varieties. Previous studies have failed to identify any structural differences between host-associated populations, suggesting a single gene pool. Our recent molecular study of scabies in people and dogs, from Aboriginal communities in the Northern Territory and the North and South Americas, using DNA fingerprinting techniques, suggested mites cluster by host species with no evidence of cross-transmission. However although this data seems to suggest that these sub-species deserve species status, another molecular study suggests Sarcoptes is a single species, presumably a result of interbreeding. Understanding interbreeding between populations is important in the control of the disease and in controlling resistance to acaricides. We wish to further characterise the genetic separation of different 'strains' or populations of mites by studying the evolutionary gene flow between host-associated populations. We will use a mitochondrial DNA marker that will clarify fine scale transmission processes and more clearly delineate the biological species status of S. scabiei. Recent in vitro data and clinical evidence in a patient with severe crusted scabies indicated resistance to ivermectin, the treatment of choice for these patients. We will investigate the role and genetic mechanisms of ivermectin resistance. This is important for future control programs, as acaricide resistance can spread rapidly in parasite populations.Read moreRead less