Studies in iron metabolism in Mycobacterium smegmatis, Mycobacterium avium and other Mycobacteria
Research in this thesis is concerned with iron metabolism in Mycobacteria, with special regard to Mycobacterium smegmatis. A study of the enzyme ferrimycobactin reductase from this organism is made. This enzyme is believed to be responsible for the release of iron from ferrimycobactin at the cell wall-cytoplasm interface. The aim of this study is to characterise the activity further, with a view to understanding its mode of action. Additionally, an examination is carried out of the levels of certain important cellular components during iron-deficient and iron-sufficient growth of M. smegmatis. This is to observe what 'economies' the cell must make in times of shortage of an essential nutrient such as iron. The response of the cell, when growing iron-deficiently, is monitored when a sudden supply of iron is presented to the cell. The iron is added in several different 'forms' to determine whether these forms of addition of iron influence the response of the cell. Mycobactin is also employed in an attempt to resolve the overlap between M. avium and M. intracellulare. By examination of the mycobactins produced by strains of these organisms, it is hoped to determined whether the M. avium-intracellulare complex consists of one or two species. Lastly, a brief study is made of several Mycobacteria that are dependent upon mycobactin for growth, to determine whether these organisms produce a mycobactin of their own.