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Clostridium acetobutylicum P262 is an endospore-forming Gram positive anaerobic bacterium, and for many years this organism has been used in the industrial fermentation for the production of acetone and butanol from carbohydrate substrates. The aims of this thesis included studies on small phosphorylated molecules involved in energy metabolism and cell differentiation, and an investigation into the genetics and molecular biology of C. acetobutylicum electron transport genes. To facilitate quantitation of nucleoside triphosphates in extracts of C. acetobutylicum, a chromatographic data acquisition and analysis system was constructed. Samples were prepared from C. acetobutylicum cultures by treatment with formic acid, and nucleotides contained in these extracts were separated by strong anion exchange HPLC. The developed manual integration system features the ability to collect and store chromatographic data, allowing for multiple integration using different calibration curves. Nucleoside triphosphate profiles were obtained from batch fermentations of the C. acetobutylicum P262 wild type, sporulation deficient (spo-1) and solvent deficient (ds-1) strains. The nucleoside triphosphate profiles of the wild type and spo-1 mutant were similar and were characterized by a trough in nucleotide levels which occurred just prior to the pH break point, the onset of the stationary growth phase, clostridial stage formation and the transition from the acidogenic to the solventogenic phase. The nucleoside triphosphate concentrations during the exponential growth phase were much lower than those found during the stationary phase. Exponential phase nucleotide levels in the cls-1 mutant were comparable to those observed in the wild type and spo-1 mutant. Unlike the wild type and spo-1 strains, the cls-1 mutant, which does not switch to solventogenesis, did not demonstrate an increase in nucleotide levels after the cessation of cell division. The involvement of nucleotide levels, particularly that of GTP, in the differentiation of C. acetobutylicum was indicated by the effect of inhibitors, which have been shown to decrease ribonucleotide levels in other organisms and cause an increase in sporulation. The antibacterial agent metronidazole, was used as a tool for the isolation of C. acetobutylicum electron transport genes. Since it was desired to clone these genes in Escherichia coli, and investigation into the activation of metronidazole by E. coli strains was necessary. E. coli strains with lesions in their DNA repair systems were more susceptible to metronidazole than wild type strains. However, it has been reported that DNA repair deficient strains of E. coli that also had a diminished ability to reduce chlorates and nitrates were no more susceptible to metronidazole than their wild type parents (Jackson et al., 1984; Yeung et al., 1984). To isolate a suitable E. coli cloning host for the selection of C. acetobutylicum electron transport genes which activated metronidazole, transposon mutagenesis of the recA E. coli strain CC118 with TnphoA, was used to construct the recA, metronidazole resistant E. coli strain Fl9. F19 was shown to have diminished nitroreductase activity, which was presumed to be responsible for the metronidazole resistant phenotype. However, the recA mutation renders E. coli F19 highly susceptible to the reduced toxic intermediates of metronidazole. The E. coli F19 recA, nitroreductase deficient mutant was used for the isolation of C. acetobutylicum genes on recombinant plasmids which activated metronidazole. Twenty-five E. coli F19 clones which contained different recombinant plasmids were isolated. The clones were tested for nitroreductase, pyruvate-Fd­oxidoreductase and hydrogenase activities. Nitroreductase and pyruvate-Fd­oxidoreductase activity was not demonstrated in any of the isolated clones, and only one clone tested positive for hydrogenase activity. DNA hybridization and restriction endonuclease mapping revealed that four of the C. acetobutylicum insert DNA fragments on recombinant plasmids were linked in an 11.1 kb chromosomal fragment. It was determined that this 11.1 kb fragment contained at least two regions responsible for activating metronidazole. The one gene responsible for making E. coli F19 extremely sensitive to metronidazole was localized to a 2 kb region. The nucleotide sequence of this 2 kb region was determined and two truncated open reading frames and one complete open reading were present. The complete open reading frame was shown to be responsible for activating metronidazole. The deduced amino acid sequence of this open reading frame was determined to be 160 amino acids in length, and database searches showed good similarity to flavodoxin proteins from many organisms. Based on alignments to the amino acid sequences of these flavodoxins, as well as the fact that Chen and Blanchard (1979) reported that reduced flavodoxin can transfer electrons to metronidazole, the sequence corresponding to this C. acetobutylicum metronidazole activating gene was identified as coding for a flavodoxin gene. The role of flavodoxin in C. acetobutylicum and other organisms is presented. Possible relationships between the cloned C. acetobutylicum flavodoxin gene and metronidazole sensitivity are discussed.