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Selected Works of Jeffrey Margolis
Article
Contributions of Francisella tularensis subsp. novicida Chitinases and Sec Secretion System to Biofilm Formation on Chitin
Applied and Environmental Microbiology (2010)
  • Jeffrey J. Margolis, Stanford University School of Medicine
  • Sahar H. El-Etr, Lawrence Livermore National Laboratory
  • Lydia-Marie Joubert, Stanford University School of Medicine
  • Emily Moore, Brigham Young University
  • Richard Robinson, Brigham Young University
  • Amy Rasley, Lawrence Livermore National Laboratory,
  • Alfred M. Spormann, Stanford University
  • Denise M. Monack, Stanford University School of Medicine
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Abstract
Francisella tularensis, the zoonotic cause of tularemia, can infect numerous mammals and other eukaryotes.
Although studying F. tularensis pathogenesis is essential to comprehending disease, mammalian infection is
just one step in the ecology of Francisella species. F. tularensis has been isolated from aquatic environments and
arthropod vectors, environments in which chitin could serve as a potential carbon source and as a surface for
attachment and growth. We show that F. tularensis subsp. novicida forms biofilms during the colonization of
chitin surfaces. The ability of F. tularensis to persist using chitin as a sole carbon source is dependent on
chitinases, since mutants lacking chiA or chiB are attenuated for chitin colonization and biofilm formation in
the absence of exogenous sugar. A genetic screen for biofilm mutants identified the Sec translocon export
pathway and 14 secreted proteins. We show that these genes are important for initial attachment during biofilm
formation. We generated defined deletion mutants by targeting two chaperone genes (secB1 and secB2) involved
in Sec-dependent secretion and four genes that encode putative secreted proteins. All of the mutants were
deficient in attachment to polystyrene and chitin surfaces and for biofilm formation compared to wild-type F.
novicida. In contrast, mutations in the Sec translocon and secreted factors did not affect virulence. Our data
suggest that biofilm formation by F. tularensis promotes persistence on chitin surfaces. Further study of the
interaction of F. tularensis with the chitin microenvironment may provide insight into the environmental
survival and transmission mechanisms of this pathogen.
Disciplines
Publication Date
January, 2010
DOI
10.1128/AEM.02037-09
Publisher Statement
Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Citation Information
Jeffrey J. Margolis, Sahar H. El-Etr, Lydia-Marie Joubert, Emily Moore, et al.. "Contributions of Francisella tularensis subsp. novicida Chitinases and Sec Secretion System to Biofilm Formation on Chitin" Applied and Environmental Microbiology Vol. 76 Iss. 2 (2010) p. 596 - 608 ISSN: 0099-2240;
Available at: http://works.bepress.com/jeffrey-margolis/3/