Role of Yersinia Murine Toxin in Survival of Yersinia pestis in the Midgut of the Flea Vector
B. Joseph Hinnebusch,1*
Amy E. Rudolph,2
Peter Cherepanov,3
Jack E. Dixon,2
Tom G. Schwan,1
Åke Forsberg3
Transmission by flea bite is a relatively recent adaptation
that distinguishes Yersinia pestis, the plague bacillus,
from closely related enteric bacteria. Here, a plasmid-encoded
phospholipase D (PLD), previously characterized as Yersinia murine
toxin (Ymt), was shown to be required for survival of Y. pestis in the midgut of its principal vector, the rat flea
Xenopsylla cheopis. Intracellular PLD activity appeared to
protect Y. pestis from a cytotoxic digestion product of
blood plasma in the flea gut. By enabling colonization of the flea
midgut, acquisition of this PLD may have precipitated the transition of
Y. pestis to obligate arthropod-borne transmission.
1 Laboratory of Human Bacterial Pathogenesis,
Rocky Mountain Laboratories, National Institute of Allergy and
Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
2 Department of Biological Chemistry,
University of Michigan Medical School, Ann Arbor, MI 48109, USA.
3 Department of Medical Countermeasures, Swedish
Defense Research Agency, S-901 82 Umeå, and Department of Molecular
Biology, Umeå University, S-901 87 Umeå, Sweden.
*
To whom correspondence should be addressed. E-mail:
jhinnebusch{at}niaid.nih.gov
Present address: Pharmacia Corporation, St. Louis, MO
63167, USA.
