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Title: Francisella tularensis type A Strains Cause the Rapid Encystment of Acanthamoeba castellanii and Survive in Amoebal Cysts for Three Weeks post Infection

Abstract

Francisella tularensis, the causative agent of the zoonotic disease tularemia, has recently gained increased attention due to the emergence of tularemia in geographical areas where the disease has been previously unknown, and the organism's potential as a bioterrorism agent. Although F. tularensis has an extremely broad host range, the bacterial reservoir in nature has not been conclusively identified. In this study, the ability of virulent F. tularensis strains to survive and replicate in the amoeba Acanthamoeba castellanii was explored. We observe that A. castellanii trophozoites rapidly encyst in response to F. tularensis infection and that this rapid encystment phenotype (REP) is caused by factor(s) secreted by amoebae and/or F. tularensis into the co-culture media. Further, our results indicate that in contrast to LVS, virulent strains of F. tularensis can survive in A. castellanii cysts for at least 3 weeks post infection and that induction of rapid amoeba encystment is essential for survival. In addition, our data indicate that pathogenic F. tularensis strains block lysosomal fusion in A. castellanii. Taken together, these data suggest that the interactions between F. tularensis strains and amoeba may play a role in the environmental persistence of F. tularensis.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
972428
Report Number(s):
LLNL-JRNL-415174
TRN: US201006%%74
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Applied Environmental Microbiology, vol. 75, no. 23, December 15, 2009, pp. 5488
Additional Journal Information:
Journal Volume: 75; Journal Issue: 23
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; AMOEBA; CYSTS; DISEASES; INDUCTION; PHENOTYPE; STRAINS

Citation Formats

El-Etr, S H, Margolis, J, Monack, D, Robison, R, Cohen, M, Moore, E, and Rasley, A. Francisella tularensis type A Strains Cause the Rapid Encystment of Acanthamoeba castellanii and Survive in Amoebal Cysts for Three Weeks post Infection. United States: N. p., 2009. Web.
El-Etr, S H, Margolis, J, Monack, D, Robison, R, Cohen, M, Moore, E, & Rasley, A. Francisella tularensis type A Strains Cause the Rapid Encystment of Acanthamoeba castellanii and Survive in Amoebal Cysts for Three Weeks post Infection. United States.
El-Etr, S H, Margolis, J, Monack, D, Robison, R, Cohen, M, Moore, E, and Rasley, A. Tue . "Francisella tularensis type A Strains Cause the Rapid Encystment of Acanthamoeba castellanii and Survive in Amoebal Cysts for Three Weeks post Infection". United States. https://www.osti.gov/servlets/purl/972428.
@article{osti_972428,
title = {Francisella tularensis type A Strains Cause the Rapid Encystment of Acanthamoeba castellanii and Survive in Amoebal Cysts for Three Weeks post Infection},
author = {El-Etr, S H and Margolis, J and Monack, D and Robison, R and Cohen, M and Moore, E and Rasley, A},
abstractNote = {Francisella tularensis, the causative agent of the zoonotic disease tularemia, has recently gained increased attention due to the emergence of tularemia in geographical areas where the disease has been previously unknown, and the organism's potential as a bioterrorism agent. Although F. tularensis has an extremely broad host range, the bacterial reservoir in nature has not been conclusively identified. In this study, the ability of virulent F. tularensis strains to survive and replicate in the amoeba Acanthamoeba castellanii was explored. We observe that A. castellanii trophozoites rapidly encyst in response to F. tularensis infection and that this rapid encystment phenotype (REP) is caused by factor(s) secreted by amoebae and/or F. tularensis into the co-culture media. Further, our results indicate that in contrast to LVS, virulent strains of F. tularensis can survive in A. castellanii cysts for at least 3 weeks post infection and that induction of rapid amoeba encystment is essential for survival. In addition, our data indicate that pathogenic F. tularensis strains block lysosomal fusion in A. castellanii. Taken together, these data suggest that the interactions between F. tularensis strains and amoeba may play a role in the environmental persistence of F. tularensis.},
doi = {},
journal = {Applied Environmental Microbiology, vol. 75, no. 23, December 15, 2009, pp. 5488},
number = 23,
volume = 75,
place = {United States},
year = {2009},
month = {7}
}