Transport Pathways Of Host-derived Iron In Schistosomes Parasites
Funder
National Health and Medical Research Council
Funding Amount
$322,091.00
Summary
This project will identify the diversity and biological roles of receptors for metabolic iron expressed on the body surface of the parasitic blood flukes (schistosomes) of humans. Schistosomes are a major health problem in many tropical countries and are responsible for significant human morbidity and lost productivity. Adult worms feed on human blood, from which derive amino acids for the production of many hundreds of eggs released per day into the human blood stream. The intense cellular resp ....This project will identify the diversity and biological roles of receptors for metabolic iron expressed on the body surface of the parasitic blood flukes (schistosomes) of humans. Schistosomes are a major health problem in many tropical countries and are responsible for significant human morbidity and lost productivity. Adult worms feed on human blood, from which derive amino acids for the production of many hundreds of eggs released per day into the human blood stream. The intense cellular response induced by parasite eggs trapped in body organs is the major cause of chronic human disease. We have discovered two intriguing phenomena of iron metabolism in schistosomes. Firstly, schistosomes have a greater reliance on iron than many other organisms, storing a surfeit in cells that produce the protein-rich egg shell. Secondly, a major transmembrane iron transporter of the parasites, thought to be involved in the uptake of iron, is found on the parasite external body surface and not in the parasite intestine. The extensive nutritional dependence of these worms on iron and the surface location of mediators of iron uptake raise the exciting possibility that we have uncovered a novel system that might be exploited for vaccine or drug-mediated control of these significant human parasites. If we can dissect the pathways schistosomes use to derive iron from their hosts, we may be able to generate vaccines to block this nutritional pathway, or use drugs to block embryogenesis. This project is a fact-finding mission that asks if the host-interactive tegument of these parasites is a major source of metabolic iron. Molecules we demonstrate to be present on the surface will be tested as vaccine candidates in mouse vaccine trialsRead moreRead less
Multi-copper Oxidase Mediated Iron Uptake In Ps. Aeruginosa And Other Pathogenic Bacteria: Mechanism And Role In Disease
Funder
National Health and Medical Research Council
Funding Amount
$73,500.00
Summary
Iron is essential for the growth of bacteria. One of the mechanisms used by humans (and other animals) to defend against bacteria that cause disease is to trap iron by binding it to a set of iron binding proteins eg. transferrin. In this way there is no free iron in the system, so bacteria that survive in humans have had to evolve specific mechanisms to remove the iron form these host proteins. The mechanisms of iron uptake in pathogenic bacteria have been studied extensively, and the iron uptak ....Iron is essential for the growth of bacteria. One of the mechanisms used by humans (and other animals) to defend against bacteria that cause disease is to trap iron by binding it to a set of iron binding proteins eg. transferrin. In this way there is no free iron in the system, so bacteria that survive in humans have had to evolve specific mechanisms to remove the iron form these host proteins. The mechanisms of iron uptake in pathogenic bacteria have been studied extensively, and the iron uptake systems are considered to be important of virulence factors (bacterial factors essential for causing disease). Humans and other higher organisms like Yeast have an iron uptake system that uses multi copper oxidase proteins (MCOs). These proteins have a ferroxidase activity, which converts iron from a protein bound insoluable form Fe (III) to a soluble form Fe(II), allowing it to be released from iron binding proteins. We have searched the genomes of many bacteria for a similar system and have discovered that many bacteria have MCOs. We wanted to test the idea that the bacteria MCOs we have identified may be involved in iron uptkae. If so, it would represent a huge step forward in understanding this important process and could lead to products for prevention or better treatment of infectious disease. We chose the disease causing bacterium Pseudomonas aeruginosa for our study. We have shown that the MCO has ferroxidase activity (Fe(III)>Fe(II), we have made a mutation in the MCO gene had have shown that the bacterium lacking MCO will not grow under certain conditions. These conditions are consistent with a defect in iron uptake. We have identified but not characterised several other key compnents of this iron uptake system. In the proposed work we wish to investigate all of the components of this iron uptake system in this important pathogen, and to initiate studies in other bacteria pathogens.Read moreRead less
Mechanisms Of Intestinal And Systemic Iron Homeostasis In Early Infancy
Funder
National Health and Medical Research Council
Funding Amount
$485,835.00
Summary
Iron is essential trace element for normal health. Iron requirements are particularly high during early postnatal life to meet the needs of the growing infant. To accommodate these needs, intestinal iron absorption is extremely high at this time. We have previously shown that the iron absorption mechanism during suckling differs from that in adults and this project explores that mechanism in more detail. These studies have important implications for infant nutrition and dietary supplementation.
Mechanisms Of Intestinal Iron Absorption And Consequences Of Iron Supplementation During The Perinatal Period
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
Iron intake is particularly high during pregnancy and in the newborn to meet the requirements of the growing fetus and neonate. While it is widely recommended that women take iron supplements at this time, too much iron may adversely affect pregnancy outcome. The aim of this study is to understand the factors controlling iron intake in the perinatal and the consequences of excess iron. This will provide the physiological information required to make rational decisions about iron supplementation.