Plasmids are extra mini-chromosomes that are present in many bacteria. They carry information that enables their hosts to survive and prosper in hostile environments. Plasmids are able to spread rapidly between bacteria, ensuring that the information they carry is rapidly disseminated throughout bacterial populations. Many plasmids carry information that increases the virulence of their host bacteria, because it adds to their repertoire of toxins and other adjuncts to invasiveness and colonisati ....Plasmids are extra mini-chromosomes that are present in many bacteria. They carry information that enables their hosts to survive and prosper in hostile environments. Plasmids are able to spread rapidly between bacteria, ensuring that the information they carry is rapidly disseminated throughout bacterial populations. Many plasmids carry information that increases the virulence of their host bacteria, because it adds to their repertoire of toxins and other adjuncts to invasiveness and colonisation, or enables them to survive in the presence of antibiotics. The emergence of multi-drug resistant bacteria and the rapid spread of the ability of bacteria to withstand most antibiotics available to date were mediated by plasmids. Plasmids also carry information that ensures their own survival. The consequence of this is that their bacterial hosts retain the plasmids, even when it is no longer beneficial to do so. For example, plasmids carrying information for resistance to antibiotics are not lost when their bacterial hosts grow in the absence of antibiotics. This is because plasmids have control systems, which ensure that on the one hand, replication of the plasmid keeps pace with the replication of its host, and on the other hand that the plasmid does not produce so many copies of itself that it overwhelms its host. This project examines the intricate regulatory system that a group of antibiotic-resistance plasmids uses to ensure that on average each plasmid molecule is replicated once per bacterial cell cycle. This system uses an antisense RNA, a tertiary RNA structure (pseudoknot) that acts as a translational switch, and a protein that interacts with different sequences on the plasmid to initiate replication. Detailed knowledge of the processes underlying this complex system is required if we are to develop new treatments that will lead to elimination of antibiotic-resistance and virulence-contributing plasmids from populations of pathogenic bacteria.Read moreRead less
Plasmids are additional mini-chromosomes carried by many bacteria. They carry information that enables their hosts to prosper in otherwise hostile environments. Plasmids spread rapidly between bacteria, efficiently disseminating plasmid-borne information throughout bacterial populations. Many plasmids carry information that increases the virulence of their host. The emergence of multi-drug resistant bacteria and the rapid spread of the information enabling bacteria to withstand most antibiotics ....Plasmids are additional mini-chromosomes carried by many bacteria. They carry information that enables their hosts to prosper in otherwise hostile environments. Plasmids spread rapidly between bacteria, efficiently disseminating plasmid-borne information throughout bacterial populations. Many plasmids carry information that increases the virulence of their host. The emergence of multi-drug resistant bacteria and the rapid spread of the information enabling bacteria to withstand most antibiotics available today, were mediated by plasmids. Plasmids also carry information that ensures their own survival. Consequently, their hosts retain the plasmids even when it is no longer beneficial for them to do so. For example, plasmids mediating resistance to antibiotics are not lost when bacterial hosts are grown in the absence of those antibiotics. That is because plasmids have control systems, which ensure both that replication of the plasmid keeps pace with that of its host, and that the plasmid does not produce so many copies of itself that it overwhelms its host or places it at a competitive disadvantage amongst other bacteria. This project examines the intricate regulatory system that enables two groups of antibiotic-resistance plasmids to ensure that, on average, each plasmid molecule is replicated once per bacterial cell cycle. This system uses a tertiary RNA structure as a molecular switch, an antisense RNA as the regulator of this switch, and a protein that interacts with DNA sequences on the plasmid and with a bacterial protein, to initiate replication. Information gained from studies of plasmid systems is essential to the development of treatments for the elimination of antibiotic-resistance and virulence-contributing plasmids from populations of pathogenic bacteria. Antisense RNAs are not only a powerful research tool, but are also being developed for therapeutic use. Understanding how these RNAs interact with their targets will increase their effectiveness.Read moreRead less
DNA Segregation In Multiresistant Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$306,592.00
Summary
Strains of Golden Staph bacteria resistant to many antibiotics are a major cause of hospital-acquired, and increasingly community-acquired, infections in Australia and around the world. Bacterial growth depends on the faithful inheritance of genetic material, which is facilitated by active DNA segregation. This project will elucidate key aspects of segregation processes so that treatments can be devised that interfere with the growth of this important pathogen and the development of resistance.
Identification And Analysis Of Novel Replication Initiation Factors In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$311,789.00
Summary
Multi-drug resistant Golden staph is a serious medical problem around the world because strains are often resistant to commonly used treatments; new drugs are therefore urgently required. DNA replication is a fundamental process that is essential for the survival of all cellular organisms. This project aims to identify and characterise novel factors involved in DNA replication in Golden staph, which represent potential drug targets.