Browsing by Author "Muruke, Masoud Hadi Salum"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Regulation of Nitrogen Metabolism in Bacillus fastidiosus
    (University of Dar es Salaam, 1993) Muruke, Masoud Hadi Salum
    Some aspects of nitrogen metabolism in Bacillus fastidiosus are reported. Chapter 1 deals with the general information on B. fastidiosus as reported by other workers. The organism is reported to exhibit complex behaviour in terms of its nutritional requirements. General characteristics of the organism are studied and reported in Chapter 2. Growth experiments confirmed that only urate, allantoin and allantoate are used either as sole carbon and nitrogen source or as nitrogen source in the presence of glycerol as carbon source. Chapter 3 reports on the growth of B. fastidiosus on ammonium as a nitrogen source under defined conditions . In the presence of small amounts of brain heart infusion (BHI) and allantoin (or allantoate or urate), B. fastidiosus utilized externally supplied ammonia as a nitrogen source. Contrary to the previous observations, transport of ammonia into the cells was thus possible. The internal ammonium pools of allantoin/glycerol-grown cells did not differ with cells grown on ammonia/glycerol, but generally increased with the increase in allantoin concentration. In Chapter 4 additional nitrogen sources for B. fastidiosus are reported. Urea and ureidoglycolate were used as growth substrates only in the presence of brain heart infusion and allantoin. The specific activities of NADP-dependent glutamate dehydrogenase (GDH) of cells grown on different concentrations of allantoin, ammonia, urea and ureidoglycolate are reported. The results indicate that NADPdependent GDH activity is regulated only by the allantoin concentrations. Furthermore, the regulation is not linked with the internal ammonium concentrations of the cells or the concentration of the externally supplied ammonia. Chapter 5 describes the results on the regulation of some enzymes involved in allantoin degradation namely, allantoinase, urease, glyoxylate carboiigase and NADPdependent GDH, and an enzyme involved in glycerol metabolism, glycerol-3-phosphate dehydrogenase. Only NADP-dependent GDH was found to be regulated by allantoin or allantoate. Glycerol-3-phosphate dehydrogenase was found to be induced by the presence of glycerol but not regulated by its concentrations. Other enzymes studied were found to be constitutive. Specific activities of NADP-dependent GDH and urease were influenced by BHI. Chapter 6 reports on a two step purification of urate oxidase from B. fastidiosus using Fast Flow Columns. The procedure was found to be faster than the previous methods and convenient for large scale production of uricase. Having a low generation time, B. fastidiosus could be a suitable source of the enzyme uricase.