Optimisation Of Salmonella Genotyping And Epidemiological Data Analysis For Detection And Investigation Of Outbreaks
Funder
National Health and Medical Research Council
Funding Amount
$508,051.00
Summary
Bacteria known as salmonella are the most important causes of food-borne diarrhoeal disease. They occasionally cause potentially fatal septicaemia, especially in young children and people with underlying disease. We estimate that more than 80,000 cases of salmonella infection occur in Australia, each year, at a cost to the community of $37 million. Salmonella are divided into more than 2000 different types, but one - called Typhimurium - causes about 40% of infections and a few others cause most ....Bacteria known as salmonella are the most important causes of food-borne diarrhoeal disease. They occasionally cause potentially fatal septicaemia, especially in young children and people with underlying disease. We estimate that more than 80,000 cases of salmonella infection occur in Australia, each year, at a cost to the community of $37 million. Salmonella are divided into more than 2000 different types, but one - called Typhimurium - causes about 40% of infections and a few others cause most of the rest. This means that is difficult to distinguish cases of salmonella infection that have originated from one source (an outbreak) from cases that have originated from another. Without this information, is it hard to track the source, which is usually inadequately cooked meat or chicken another food that has been contaminated with salmonella after preparation. There are several existing methods for fingerprinting salmonella, but they are quite slow or do not distinguish different strains well enough to identify outbreaks quickly. This means that sources of contaminated food are often not identified in time to prevent more cases occurring. We aim to develop a faster and more discriminatory system for fingerprinting salmonella, based on novel technology that can identify many small genetic sequences that occur in different combinations in different strains. As well, we will develop electronic scanning tools that will link the fingerprints of the salmonella strains with information about the people infected with them, such as the types of food and places where they have eaten, to identify patterns or clusters that indicate a common source. The more rapidly this can be done the sooner the source of contaminated food can be found and eliminated and additional cases can be prevented. This has important implications for public health - it will increase food safety and reduce illness and economic loss.Read moreRead less
Use Of Peptides From Phage Display Libraries To Probe The Function Of AMA-1 And Other Malaria Surface Proteins
Funder
National Health and Medical Research Council
Funding Amount
$316,650.00
Summary
Malaria remains a major cause of mortality and morbidity worldwide. Much current research is aimed at exploring the molecular interactions between malarial proteins and host components in order to gain a deeper understanding of parasite virulence mechanisms, design alternative anti-malarial approaches and improve vaccine design. The apical membrane antigen-1( AMA-1) is a surface exposed protein which is thought to play a crucial role in invasion of red blood cells by malaria parasites, and is cu ....Malaria remains a major cause of mortality and morbidity worldwide. Much current research is aimed at exploring the molecular interactions between malarial proteins and host components in order to gain a deeper understanding of parasite virulence mechanisms, design alternative anti-malarial approaches and improve vaccine design. The apical membrane antigen-1( AMA-1) is a surface exposed protein which is thought to play a crucial role in invasion of red blood cells by malaria parasites, and is currently one of the leading asexual stage vaccine candidates. While antibodies to AMA-1 prevents malaria invasion, little is known about the role of the antigen in the invasion process. The aim of this proposal is to investigate the molecular interactions that makes AMA-1 an important player in the invasion process. We propose to map the regions of AMA-1 responsible for binding a set of peptides which we have isolated from random peptide libraries. Since these peptides inhibit the invasion of parasites into red blood cells, regions of AMA1- that bind these peptides will be of functional significance. A further outcome will be the identification of peptide residues essential for the inhibition of invasion followed by in vitro evolution of these peptides to improve their binding and inhibitory properties. A molecular description of how AMA1 binding peptides prevent parasite invasion of host erythrocytes will improve our understanding of the invasion process, and aid in improving vaccines based on AMA-1. Furthermore, this peptide-AMA-1 interaction will be assessed as a possible target for the development of novel anti-malarial therapies. Using random peptide libraries we have selected peptides that specifically bind to other merozoite surface proteins thought to be involved in merozoite invasion of erythrocytes. The ability of these peptides to inhibit merozoite invasion will be examined and characterised as described above.Read moreRead less
Structural Basis For Inhibition Of Malaria Invasion By Targeting The Apical Membrane Antigen Of Plasmodium Falciparum.
Funder
National Health and Medical Research Council
Funding Amount
$434,134.00
Summary
3 million children die every year from malaria infections. A leading vaccine candidate is a protein from the malaria parasite called AMA1. Humans that have been infected with malaria make antibodies to this protein which can kill parasites, however little is known about how this occurs. We aim to identify regions of the protein that generate antibodies that prevent malaria parasites from invading human cells and help in the search for a vaccine against malaria.
Structure And Interactions Of The Malarial Vaccine Candidate AMA1
Funder
National Health and Medical Research Council
Funding Amount
$351,000.00
Summary
Malaria remains one the most lethal infectious diseases in the world today. It is directly responsible for 1-2 million deaths annually, many of these in children under 5 years of age. More than 300 million clinical cases are reported annually and over 40% of the global population (in excess of 2 billion people) are at risk. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial d ....Malaria remains one the most lethal infectious diseases in the world today. It is directly responsible for 1-2 million deaths annually, many of these in children under 5 years of age. More than 300 million clinical cases are reported annually and over 40% of the global population (in excess of 2 billion people) are at risk. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. AMA1 is an asexual stage antigen and a leading vaccine candidate. Little is known about the function of this protein, but it has been proposed to play a role in invasion of red blood cells. A clearer understanding of the structure of parasite antigens such as AMA1 that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens as vaccines and a deeper understanding of host-parasite interactions. The aims of this project are to determine the three-dimensional structures of the three major structural domains of AMA1 and of the complete AMA1 antigen. We shall also determine the structures, both in aqueous solution and bound to AMA1, of small peptides identified by phage display as being capable of binding to AMA1 and blocking parasite entry into red blood cells. The overall goal of this work is to determine the structure of AMA1 and define the structural basis for its interaction with small peptides capable of blocking its activity as well as the structural features necessary for AMA1 to react with protective antibodies. The structure of AMA1 will provide a molecular basis for the design of engineered antigens capable of eliciting a protective immune response against AMA1. The inhibitory peptide structures will likewise provide a molecular basis for the design of non-peptidic blockers of AMA1. Either or both of these may be useful therapeutics leads in the fight against malaria.Read moreRead less
Molecular Typing Of Salmonella Enterica Serovar Typhimurium
Funder
National Health and Medical Research Council
Funding Amount
$272,545.00
Summary
Salmonella mainly causes food poisoning and is a significant human health problem. Different Samonella forms are identified by serotyping and many serovars have been given a name . There are more than 2000 serovars. The best known serovar is Typhimurium which is the cause of 40% of salmonella infections. Typhimurium is so frequently involved in infections it is necessary to further divide it for outbreak investigations and long term monitoring of the organism. The only widely used method to subd ....Salmonella mainly causes food poisoning and is a significant human health problem. Different Samonella forms are identified by serotyping and many serovars have been given a name . There are more than 2000 serovars. The best known serovar is Typhimurium which is the cause of 40% of salmonella infections. Typhimurium is so frequently involved in infections it is necessary to further divide it for outbreak investigations and long term monitoring of the organism. The only widely used method to subdivide Typhimurium is phage typing, which is done only in major laboratories (2 in Australia). Phage typing is based on lysis patterns of a test isolate to a set of 34 phages. Phage typing has played a crucial role in tracking the organism, for example the emergence of a multidrug resistance new type (DT204c) in UK and US. The technique is simple but the problem is that reactions vary with slight change in conditions and scoring the reaction results is very subjective. We propose to replace the typing system with one based on the DNA method PCR, so it will be simple, fast and accurate. We will use a DNA fingerprinting technique called AFLP (amplified fragment length polymorphism) to find markers (DNA segments) that are specific to phage types and design PCR assays based on the markers we find. Such a typing system will retain the essence of phage typing by providing continuity of the valuable epidemiological database on phage types. Further the typing system could easily be expanded to accommodate any new types by finding more markers while the current phage typing system is very difficult to expand (last done in 1977 and is behind in our needs). This project will establish a general approach for designing typing systems based on molecular biology for other pathogens and could have a major impact on the surveillance of bacterial infections in the 21st century.Read moreRead less
Structure And Interactions Of The Malarial Surface Antigen AMA1
Funder
National Health and Medical Research Council
Funding Amount
$242,545.00
Summary
Malaria remains one of the most serious infectious diseases in the world today, being responsible for 1-2 million deaths annually. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. A clearer understanding of the structure of antigens in the parasite that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens ....Malaria remains one of the most serious infectious diseases in the world today, being responsible for 1-2 million deaths annually. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. A clearer understanding of the structure of antigens in the parasite that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens as vaccines and a deeper understanding of the host-parasite interaction. AMA1 is an asexual stage antigen and a leading vaccine candidate. Little is known about the function of this protein, but it has been proposed to play a role in invasion of red blood cells. The specific aims of this project are to determine the three-dimensional structures of the three major structural domains of AMA1 and of the complete AMA1 ectodomain. The interaction of one or more of these domains with Fab fragments of protective antibodies raised against intact AMA1 will then be investigated. We also intend to determine the conformations, both in aqueous solution and bound to AMA1, of oligopeptides identified by phage display as binding to AMA1 and blocking its binding to red blood cells. The overall goals of this work are to determine the structure of AMA1 and to define the structural basis for its interaction with antibodies and small peptides that are capable of blocking its activity. This information will provide a molecular basis for the design of either synthetic antigens capable of eliciting a protective immune response against AMA1 or peptidomimetic inhibitors of AMA1. Either or both of these may be useful in the prevention or treatment of malaria.Read moreRead less