Date of Award


Degree Name

Master of Science


Biological Sciences

First Advisor

Dr. Robert Eisenberg

Second Advisor

Dr. Karim Essani

Third Advisor

Dr. Silvia Rossbach

Access Setting

Masters Thesis-Open Access


The L-arabinose utilization pathway in Pseudomonas fluorescens is a unique metabolic pathway. In Pseudomonas, L-arabinose is converted to the end product α-ketogluterate and does not involve phosphorylated intermediates. This differs from the well studied L-arabinose pathway found in Escherichia coli which contains phosphorylated intermediates.

The enzymes of the L-arabinose pathway have been shown to be induced in the presence of L-arabinose in P. saccharophila. The current study determined regulatory properties of previously cloned chromosomal fragments of P. fluorescens which confer an L-arabinose positive phenotype to the surrogate host, Pseudomonas putida. Cells of P. putida containing plasmids pPZ221, pPZ222, pPZ224, pPZ226, pPZ227, pPZ228, or pPZ229 were grown on various substrates which provided sole carbon and energy sources and crude cell-free extracts of these cells were assayed for the enzyme L-arabinose dehydrogenase. The specific activities (μmole/min/mg protein) for L-arabinose dehydrogenase indicated that this enzyme was inducible and also expressed at high constitutive levels under some, but not all, growth conditions.

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