Safety in numbers: Bacterial aggregation and adaptation to oxidative stress. This project is a new collaboration which links two molecular microbiologists with the complementary skills required to make new insights into the molecular processes that underpin bacterial aggregation and biofilm formation. Biofilms are of immense significance in medical, industrial and environmental settings and so the fundamental information gained from this project will have wider relevance to the field of microbio ....Safety in numbers: Bacterial aggregation and adaptation to oxidative stress. This project is a new collaboration which links two molecular microbiologists with the complementary skills required to make new insights into the molecular processes that underpin bacterial aggregation and biofilm formation. Biofilms are of immense significance in medical, industrial and environmental settings and so the fundamental information gained from this project will have wider relevance to the field of microbiology. An outcome of this proposal will be fundamental knowledge about the production of surface adhesins that will form the basis for rational treatment of disease in the future. Prevention of aggregation and biofilm formation would make bacterial populations more susceptible to conventional antibiotic treatment.Read moreRead less
Molecular mechanisms of pilin glycosylation in Neisseria: a model system for protein glycosylation in bacteria. The disease causing bacteria Neisseria meningitidis and Neisseria gonorrhoeae are important human pathogens. Cell surface structures, called pili, are known to be important in allowing the bacteria to stick to host cells. Genetic and structural studies have identified that the protein subunits, which make up pili, are glycosylated - modified by the addition of sugars. Until recently ....Molecular mechanisms of pilin glycosylation in Neisseria: a model system for protein glycosylation in bacteria. The disease causing bacteria Neisseria meningitidis and Neisseria gonorrhoeae are important human pathogens. Cell surface structures, called pili, are known to be important in allowing the bacteria to stick to host cells. Genetic and structural studies have identified that the protein subunits, which make up pili, are glycosylated - modified by the addition of sugars. Until recently glycosylation of Gram-negative bacterial proteins was not thought to occur, however our recent work with these bacteria, and other groups studying Pseudomonas and Campylobacter, have shown that this process may be widespread. In our previous studies, we have identified and analysed a number of genes involved in pili glycosylation, in bacteria, which make known sugar structures. We have used this information to developed models for how the biochemistry and physiology of the glycosylation system may work. With a well-established structure and many genes already identified, glycosylation in Neisseria represents the best available model system to study this novel and important process. In the proposed study we describe experiments planned to test our models and reveal the molecular detail of this process. This study could lead to major advances in our understanding of this process and, when understood, may have future applications in biotechnology.Read moreRead less
A comparative genomics approach to understanding host-endosymbiont interactions. Australia's unique ecosystems are vulnerable to invasion by exotic pests that threaten agriculture and human health. The bacterial symbiont Wolbachia is found in many major pests of agricultural and medical importance. Our results will give insights into how Wolbachia spreads into host populations and improve its use as a tool to impair insect transmission of disease, e.g. as an agent to carry genes into an insect p ....A comparative genomics approach to understanding host-endosymbiont interactions. Australia's unique ecosystems are vulnerable to invasion by exotic pests that threaten agriculture and human health. The bacterial symbiont Wolbachia is found in many major pests of agricultural and medical importance. Our results will give insights into how Wolbachia spreads into host populations and improve its use as a tool to impair insect transmission of disease, e.g. as an agent to carry genes into an insect population that limit disease transmission. Our results will also make fundamental contributions to understanding host-parasite evolution, host-parasite communication, and insect developmental processes, and will be of interest to a large international community of researchers in this field. Read moreRead less
The host specificity of bacterial pathogens. The vast majority of microorganisms that cause diseases in animals are host specific. In other words, they cause disease exclusively in a particular animal species, but are harmless for others. Despite considerable recent advances in our understanding of the mechanisms used by microorganisms in general to cause disease, in most cases the underlying basis of host-specificity is not known. In this project, we will use two animal pathogens, rabbit-spe ....The host specificity of bacterial pathogens. The vast majority of microorganisms that cause diseases in animals are host specific. In other words, they cause disease exclusively in a particular animal species, but are harmless for others. Despite considerable recent advances in our understanding of the mechanisms used by microorganisms in general to cause disease, in most cases the underlying basis of host-specificity is not known. In this project, we will use two animal pathogens, rabbit-specific enteropathogenic E. coli and the closely related bacterium, Citrobacter rodentium, which specifically infect rabbits and mice respectively, to investigate the molecular basis of host specificity.Read moreRead less
The biology of integrons and their role in bacterial adaptation. Bacteria evolve in ways that animals and plants do not. One of the tools available is the ability to share genes amongst individuals in a community. One example of this is the very rapid spread of antibiotic resistance genes in pathogens. Here we will be studying a genetic element that greatly contributes to this horizontal spread of genes. This will lead to a better understanding of how bacteria work, the direct benefits of whic ....The biology of integrons and their role in bacterial adaptation. Bacteria evolve in ways that animals and plants do not. One of the tools available is the ability to share genes amongst individuals in a community. One example of this is the very rapid spread of antibiotic resistance genes in pathogens. Here we will be studying a genetic element that greatly contributes to this horizontal spread of genes. This will lead to a better understanding of how bacteria work, the direct benefits of which includes the discovery of new pathways and genes for the biotechnology industry and greater understanding of how bacteria cause disease in us, other animals and in commercial crops.Read moreRead less
A functional genomic approach for understanding metal ion adaptation in marine cyanobacteria. Unicellular marine cyanobacteria constitute 20-40% of total marine chlorophyll biomass and carbon fixation, and hence significantly impact the global carbon cycle and are very relevant to combating global warming. This research will reveal some of the major mechanisms by which marine cyanobacteria have adapted to metal levels in coastal and oligotrophic environments. Thus these results will help us und ....A functional genomic approach for understanding metal ion adaptation in marine cyanobacteria. Unicellular marine cyanobacteria constitute 20-40% of total marine chlorophyll biomass and carbon fixation, and hence significantly impact the global carbon cycle and are very relevant to combating global warming. This research will reveal some of the major mechanisms by which marine cyanobacteria have adapted to metal levels in coastal and oligotrophic environments. Thus these results will help us understand the distribution and diversity of these organisms in relation to global primary productivity. They will also lead to the development of more robust biomarkers for metal stress and pollution in coastal environments.Read moreRead less
Identifying Novel Biosynthetic Pathways in Mycobacteria using DNA Microarray Technology. DNA microarrays are a powerful new bioinformatics-based technology and an ideal tool for characterising complex biosynthetic pathways since the expression of all genes in the bacterial genome can be monitored in a single experiment. In this project we aim to construct and use a DNA microarray to identify novel biosynthetic pathways in mycobacteria. Of particular interest are pathways used to create compone ....Identifying Novel Biosynthetic Pathways in Mycobacteria using DNA Microarray Technology. DNA microarrays are a powerful new bioinformatics-based technology and an ideal tool for characterising complex biosynthetic pathways since the expression of all genes in the bacterial genome can be monitored in a single experiment. In this project we aim to construct and use a DNA microarray to identify novel biosynthetic pathways in mycobacteria. Of particular interest are pathways used to create components of the highly complex and poorly characterised cell wall. Since this structure is unique in the bacterial world, we expect to identify and characterise pathways that are unique to mycobacteria.Read moreRead less
Autotransporter proteins of Escherichia coli. Autoransporters are a novel class of proteins associated with bacterial virulence properties such as adhesion, invasion and biofilm formation. Despite this, limited information is available on their functional role. The aim of this project is to characterize several of the autotransporter proteins from pathogenic E. coli. The likely contribution of these proteins to infection suggests that they are potential targets for strain attenuation and vaccine ....Autotransporter proteins of Escherichia coli. Autoransporters are a novel class of proteins associated with bacterial virulence properties such as adhesion, invasion and biofilm formation. Despite this, limited information is available on their functional role. The aim of this project is to characterize several of the autotransporter proteins from pathogenic E. coli. The likely contribution of these proteins to infection suggests that they are potential targets for strain attenuation and vaccine strain construction. Many of these proteins also mediate bacterial aggregation and are therefore targets for novel drugs that inhibit this process. The project will be carried out with a high profile partner from Denmark and will provide opportunity for travel and technology development. Read moreRead less
Autotransporter proteins of enterohemorrhagic Escherichia coli O157:H7. Escherichi (E.) coli O157:H7 has caused hundreds of outbreaks in the United States and United Kingdom. Although not currently a major problem in Australia, the emergence of E. coli O157:H7 here would have serious implications for our meat and livestock industry. This study will provide important information for the selection of vaccine antigens used to prevent the colonisation of cattle with E. coli O157:H7 and other diarrho ....Autotransporter proteins of enterohemorrhagic Escherichia coli O157:H7. Escherichi (E.) coli O157:H7 has caused hundreds of outbreaks in the United States and United Kingdom. Although not currently a major problem in Australia, the emergence of E. coli O157:H7 here would have serious implications for our meat and livestock industry. This study will provide important information for the selection of vaccine antigens used to prevent the colonisation of cattle with E. coli O157:H7 and other diarrhoeagenic E. coli serotypes. A direct outcome of this will be improved human health, as E. coli O157:H7 can cause life threatening infections in humans. The study will also examine the contribution of specific adhesins to biofilm formation; measures to prevent biofilm formation may reduce the persistence and spread of E. coli O157:H7 in the environment.Read moreRead less
Host cell targets of bacterial virulence effectors. The research described in this proposal will result in a better understanding of the cell biology of host-pathogen interactions. We are in a unique position to analyze the importance of protein/protein interactions between bacterial virulence determinants and host cell proteins using a range of cell biology techniques to address the fundamental, molecular basis of the host-pathogen interaction. In addition we will construct a new genetic tool ....Host cell targets of bacterial virulence effectors. The research described in this proposal will result in a better understanding of the cell biology of host-pathogen interactions. We are in a unique position to analyze the importance of protein/protein interactions between bacterial virulence determinants and host cell proteins using a range of cell biology techniques to address the fundamental, molecular basis of the host-pathogen interaction. In addition we will construct a new genetic tool to identify novel bacterial virulence determinants. We anticipate that a greater knowledge of the factors that contribute to the host-pathogen interaction will provide new insights into the subversion of host cell processes by bacterial pathogens of animals, plants and humans.
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