ABSTRACT
CONTENTS 10.1 Introduction .............................................................................................................................. 129 10.2 Gluconeogenesis in Saccharomyces cerevisiae ....................................................................... 130 10.3 General Pattern of Control of Catabolism in Aspergillus nidulans ........................................ 131 10.4 Regulation by Induction ........................................................................................................... 132 10.5 Substrates Metabolized Via the TCA Cycle ............................................................................ 133 10.6 Acetate Utilization ................................................................................................................... 133 10.7 Organelle Localization of Pathways ........................................................................................ 134 10.8 Peroxins .................................................................................................................................... 135 10.9 Fatty Acid Utilization ............................................................................................................... 136 10.10 Regulation of Fatty Acid Catabolism ....................................................................................... 137 10.11 Control of Gluconeogenesis ..................................................................................................... 138 10.12 Conclusions .............................................................................................................................. 139 References ........................................................................................................................................... 139
10.1 Introduction Most fi lamentous fungi have a saprophytic lifestyle where growth entails the utilization of environmental compounds as nutrients. These include sources of carbon, nitrogen, phosphorus, and sulfur. Of particular relevance here is the ability of fungi to metabolize a very diverse range of carbon compounds. Where a substrate is available as the sole carbon source then all cellular components must be synthesized from this compound via appropriate metabolic pathways. This, therefore, requires the organism to have the ability to rearrange the expression of gene-encoding enzymes catalyzing the appropriate steps in the pathways according to the substrates available. Commonly there is induction of enzymes specifi c to the breakdown of the particular compound. In addition, however, there is also a requirement for altering the central pathways of carbon metabolism so that the products of catabolism can be used to generate essential carbon-containing intermediates for biosynthesis of cellular components as well as energy and reducing power to deal with metabolic stresses. Furthermore, carbon metabolism plays a key role in various developmental stages such as asexual and sexual reproduction and for the provision of substrates for secondary metabolism. For fungal pathogens utilization of endogenous and exogenous carbon sources may have profound effects on pathogenicity [1,2].
