Topics covered in this volume:BR 1. Metal ion transport in eukaryotic microorganisms: insights from ISaccharomyces cerevisiae/IBR 2. Iron uptake by fungi: contrasted mechanisms with internal or external reductionBR 3. Dynamics of metabolism and its interactions with gene expression during sporulation in ISaccharomyces cerevisiae/IBR 4. Carbon and nitrogen metabolism in rhizobiumBR 5. Redundancy of aerobic respiratory chains in bacteria? Routes, reasons and regulations