A microscopical examination of curdlan production by an Agrobacterium sp. We will investigate the secretion of the insoluble polysaccharide curdlan, a (1,3)-beta-glucan, from the surfaces of Agrobacterium cells and the assembly of the individual polysaccharide chains into microfibrils. Using state-of-the-art techniques in time lapse and electron microscopy we will compare the images of wild type curdlan-producing cells with those of mutants impaired in the production of curdlan. The outputs will ....A microscopical examination of curdlan production by an Agrobacterium sp. We will investigate the secretion of the insoluble polysaccharide curdlan, a (1,3)-beta-glucan, from the surfaces of Agrobacterium cells and the assembly of the individual polysaccharide chains into microfibrils. Using state-of-the-art techniques in time lapse and electron microscopy we will compare the images of wild type curdlan-producing cells with those of mutants impaired in the production of curdlan. The outputs will be information on the mechanics of curdlan production that will complement that emerging from our molecular biological and biochemical studies. These will have implications for understanding bacterial polysaccharide production in general and may have a commercial outcome in enhanced curdlan production.Read moreRead less
Ubiquinone in Giardia: Amitochondrial component in an amitochondriate parasite. Giardia intestinalis is a fascinating organism, it is one of the most primitive nucleated organisms known and is responsible for ~280 million infections annually. Ubiquinone is usually associated with mitochondrial function, however it has been found in Giardia, which lacks this organelle. Our initial studies show that in Giardia, ubiquinone plays essential roles in electron transport pathways associated with membr ....Ubiquinone in Giardia: Amitochondrial component in an amitochondriate parasite. Giardia intestinalis is a fascinating organism, it is one of the most primitive nucleated organisms known and is responsible for ~280 million infections annually. Ubiquinone is usually associated with mitochondrial function, however it has been found in Giardia, which lacks this organelle. Our initial studies show that in Giardia, ubiquinone plays essential roles in electron transport pathways associated with membrane energisation and oxidative stress management. Elucidation of these mechanisms will have a major impact on the understanding of Giardia and other anaerobic organisms as well as being of significant evolutionary and medical importance.
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NmlR-dependent thiol-based redox systems and their role in global stress responses in bacteria. All cells sense changes to their environment and respond by altering their metabolism. A major environmental change is oxidative stress which damages cells. Cells have the ability to sense oxidative stress and alter metabolic processes to defend against the damage that it elicits. This proposal will characterize a novel oxidative stress defense system that is found in a number of bacterial pathogens t ....NmlR-dependent thiol-based redox systems and their role in global stress responses in bacteria. All cells sense changes to their environment and respond by altering their metabolism. A major environmental change is oxidative stress which damages cells. Cells have the ability to sense oxidative stress and alter metabolic processes to defend against the damage that it elicits. This proposal will characterize a novel oxidative stress defense system that is found in a number of bacterial pathogens that need to defend themselves against attack by the host. The project may identify new ways to manage these bacterial pathogens. It may also provide an insight into oxidative stress defense processes that are linked to pathologies in humans.Read moreRead less
The Fine Tuned Physiology of Microaerophilic Gastric Spirilla. The aim of the project is to understand the molecular basis of fundamental properties of the physiology of enterogastric spiral bacteria of the genera Campylobacter and Helicobacter. The characteristics of these obligate microaerophiles which will be investigated are their aerobic respiratory chains, the special metabolites and enzymes involved in thiol-disulphide redox balance, and their essential requirement for carbon dioxide. Mic ....The Fine Tuned Physiology of Microaerophilic Gastric Spirilla. The aim of the project is to understand the molecular basis of fundamental properties of the physiology of enterogastric spiral bacteria of the genera Campylobacter and Helicobacter. The characteristics of these obligate microaerophiles which will be investigated are their aerobic respiratory chains, the special metabolites and enzymes involved in thiol-disulphide redox balance, and their essential requirement for carbon dioxide. Microaerobes include some bacteria, archea and protozoa. Realisation of the widespread habitats and importance of microaerophiles, has led recently to a vigorous interest in understanding their physiology. Knowledge of the basic properties of microaerophily has potential applications to Environmental Microbiology, Agriculture, Industrial Microbiology, Veterinary Science and Medicine.Read moreRead less
Regulation of proteolysis by specialised adaptor proteins. Training research scientists of the future forms an integral part of this research program and this collaboration will provide an excellent opportunity for young Australian scientists to be exposed to the very professional and competitive environment of basic research, as it exists in Germany. It will expose early career researchers to new ideas and emerging methodologies arming them with valuable skills, which they will transfer to Aust ....Regulation of proteolysis by specialised adaptor proteins. Training research scientists of the future forms an integral part of this research program and this collaboration will provide an excellent opportunity for young Australian scientists to be exposed to the very professional and competitive environment of basic research, as it exists in Germany. It will expose early career researchers to new ideas and emerging methodologies arming them with valuable skills, which they will transfer to Australia. The involvement of Prof. Turgay in the Deutsche Forschungsgemeinschaft (DFG) Priority Programme: Proteolysis in Prokaryotes also provides a unique opportunity for these young researchers to interact with several of the worlds leading scientists in the area of proteolysis, enhancing Australia's reputation at the forefront of science.Read moreRead less
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
Disulfide catalysis and protein folding in bacterial virulence. The molecular mechanisms that underpin disulfide bond formation have had a major impact on our understanding of protein folding and function. This project will make a major contribution to fundamental areas of disulfide catalysis pathways in bacterial pathogens and thus help maintain a strong international profile for Australian research in this field. The work will lead to training of research scientists and students in techniques ....Disulfide catalysis and protein folding in bacterial virulence. The molecular mechanisms that underpin disulfide bond formation have had a major impact on our understanding of protein folding and function. This project will make a major contribution to fundamental areas of disulfide catalysis pathways in bacterial pathogens and thus help maintain a strong international profile for Australian research in this field. The work will lead to training of research scientists and students in techniques that include molecular genetics, protein biochemistry and structural biology. Our findings may impact future directions for vaccine research on pathogens that cause life threatening infections in humans and therefore lead to improved health and reduced health care expenditure.Read moreRead less
Structural analysis and functional inactivation of bacterial transcription complexes. RNA polymerase is an essential enzyme in all living cells. Its role is to convert the genetic information stored in genes into a message that can be converted into protein. As such, the bacterial RNA polymerase represents an ideal target for the development of new antibiotics which will be important in maintaining the health of the Australian community and also in protecting the community from the very real thr ....Structural analysis and functional inactivation of bacterial transcription complexes. RNA polymerase is an essential enzyme in all living cells. Its role is to convert the genetic information stored in genes into a message that can be converted into protein. As such, the bacterial RNA polymerase represents an ideal target for the development of new antibiotics which will be important in maintaining the health of the Australian community and also in protecting the community from the very real threat of bioterrorism organisms such as anthrax. This project is designed to identify molecules for development as new antibiotics that are effective against RNA polymerase.Read moreRead less
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
Sensing atmosphere: Understanding the HNOX-protein gas-sensing capability and how it is affected by heme-oxidation. The project investigates how gas sensing heme-proteins from the novel HNOX (Heme-Nitric Oxide) family are able to discriminate between different gaseous ligands such as O2 and NO and how oxidation of the heme alters this response. The gas-sensing capability of the HNOX proteins is crucial for organisms ranging from bacteria to humans. Thus, understanding of these signalling mechani ....Sensing atmosphere: Understanding the HNOX-protein gas-sensing capability and how it is affected by heme-oxidation. The project investigates how gas sensing heme-proteins from the novel HNOX (Heme-Nitric Oxide) family are able to discriminate between different gaseous ligands such as O2 and NO and how oxidation of the heme alters this response. The gas-sensing capability of the HNOX proteins is crucial for organisms ranging from bacteria to humans. Thus, understanding of these signalling mechanisms will have a strong impact on many scientific fields from the control of pathogen growth to human blood pressure regulation. This collaboration will establish Australian scientists and as world-leading in the field of NO and redox signalling. This development will also be of substantial benefit for the training of the next generation of Australian students and scientists.Read moreRead less