Date of Award

Spring 1993

Project Type


Program or Major


Degree Name

Doctor of Philosophy

First Advisor

Robert M Zsigray


The World Health Organization classified (Williams, 1983) Y. pestis as Y. pseudotuberculosis subsp. pestis on the basis of DNA homology, yet the two organisms cause markedly different disease. Portnoy and Falkow (1981) reported IS100 to influence the virulence of Y. pestis. IS100 was shown to be found in Y. pestis but not Y. pseudotuberculosis.

IS100 from Y. pestis was sequenced and shown by sequence analysis to fulfill the requirements of being an IS element. pIS1C, an 821 bp fragment of IS100 was transferred to Y. pseudotuberculosis Trp-Ca-, resulting in the ability of the cells to ferment rhamnose and delayed production of urease at 37$\sp\circ$C but not at 26$\sp\circ$C. These traits are normally associated with Y. pestis. Maxicell analysis revealed more products and larger products than could be expected from the coding capacity of the clone. Two-dimensional polyacrylamide gel electrophoresis analysis demonstrated a complex rearrangement of protein profile based on the presence of pIS1C. These data clearly indicate the thermo-regulatory involvement of IS100 at the molecular level.