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Microbiology

Selected Works

Jeffrey Margolis

Articles 1 - 7 of 7

Full-Text Articles in Life Sciences

Environmental Implications Of Francisella Tularensis Biofilms, Jeffrey J. Margolis '00 Mar 2017

Environmental Implications Of Francisella Tularensis Biofilms, Jeffrey J. Margolis '00

Jeffrey Margolis

Francisella tularensis survives in one of the widest environmental ranges of any pathogen. Numerous mammals and arthropod vectors are infected by this highly virulent organism. How this zoonotic pathogen persists outside of its many hosts remains unexplored. We aimed to examine how F. tularensis interacts with environmental surfaces, and hypothesized that biofilm formation may enable survival of this organism in nature. By understanding the role these surface-attached bacterial communities play in F. tularensis ecology, we hope to gain insight into the mechanisms of environmental persistence and transmission of this pathogen.

We identify chitin as a potential non-host niche for F. …

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Dermacentor Andersoni Transmission Of Francisella Tularensis Subsp. Novicida Reflects Bacterial Colonization, Dissemination, And Replication Coordinated With Tick Feeding, Kathryn E. Reif, Guy H. Palmer, Massaro W. Ueti, Glen A. Scoles, J. J. Margolis, D. M. Monack, Susan M. Noh Nov 2011

Dermacentor Andersoni Transmission Of Francisella Tularensis Subsp. Novicida Reflects Bacterial Colonization, Dissemination, And Replication Coordinated With Tick Feeding, Kathryn E. Reif, Guy H. Palmer, Massaro W. Ueti, Glen A. Scoles, J. J. Margolis, D. M. Monack, Susan M. Noh

Jeffrey Margolis

Ticks serve as biological vectors for a wide variety of bacterial pathogens which must be able to
efficiently colonize specific tick tissues prior to transmission. The bacterial determinants of tick colonization
are largely unknown, a knowledge gap attributed in large part to the paucity of tools to genetically
manipulate these pathogens. In this study, we demonstrated that Francisella tularensis subsp. novicida, for
which a complete two-allele transposon mutant library has been constructed, initially infects the midguts
of 100% of acquisition-fed Dermacentor andersoni nymphs, with stable colonization and replication during
a subsequent molt. Increased dissemination to and marked replication within …

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Contributions Of Francisella Tularensis Subsp. Novicida Chitinases And Sec Secretion System To Biofilm Formation On Chitin, Jeffrey J. Margolis, Sahar H. El-Etr, Lydia-Marie Joubert, Emily Moore, Richard Robinson, Amy Rasley, Alfred M. Spormann, Denise M. Monack Dec 2009

Contributions Of Francisella Tularensis Subsp. Novicida Chitinases And Sec Secretion System To Biofilm Formation On Chitin, Jeffrey J. Margolis, Sahar H. El-Etr, Lydia-Marie Joubert, Emily Moore, Richard Robinson, Amy Rasley, Alfred M. Spormann, Denise M. Monack

Jeffrey Margolis

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, …

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Francisella Tularensis Type A Strains Cause The Rapid Encystment Of Acanthamoeba Castellanii And Survive In Amoebal Cysts For Three Weeks Postinfection, Jeffrey J. Margolis, Sahar H. El-Etr, Denise Monack, Richard A. Robinson, Marissa Cohen, Emily Moore, Amy Rasley Nov 2009

Francisella Tularensis Type A Strains Cause The Rapid Encystment Of Acanthamoeba Castellanii And Survive In Amoebal Cysts For Three Weeks Postinfection, Jeffrey J. Margolis, Sahar H. El-Etr, Denise Monack, Richard A. Robinson, Marissa Cohen, Emily Moore, Amy Rasley

Jeffrey Margolis

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 to 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 …

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Influence Of The Hydrodynamic Environment On Quorum Sensing In Pseudomonas Aeruginosa Biofilms, Jeffrey J. Margolis, Mary Jo Kirisits, Boloroo L. Purevdorj-Gage, Benjamin Vaughan, David L. Chopp, Paul Stoodley, Matthew R. Parsek Oct 2007

Influence Of The Hydrodynamic Environment On Quorum Sensing In Pseudomonas Aeruginosa Biofilms, Jeffrey J. Margolis, Mary Jo Kirisits, Boloroo L. Purevdorj-Gage, Benjamin Vaughan, David L. Chopp, Paul Stoodley, Matthew R. Parsek

Jeffrey Margolis

We provide experimental and modeling evidence that the hydrodynamic environment can impact quorum
sensing (QS) in a <em>Pseudomonas aeruginosa</em> biofilm. The amount of biofilm biomass required for full QS induction of the population increased as the flow rate increased.

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In Vivo Negative Selection Screen Identifies Genes Required For Francisella Virulence, David S. Weiss, Anna Brotcke, Thomas Henry, Jeffrey J. Margolis, Kaman Chan, Denise M. Monack Apr 2007

In Vivo Negative Selection Screen Identifies Genes Required For Francisella Virulence, David S. Weiss, Anna Brotcke, Thomas Henry, Jeffrey J. Margolis, Kaman Chan, Denise M. Monack

Jeffrey Margolis

<em>Francisella tularensis</em> subverts the immune system to rapidly grow within mammalian hosts, often causing tularemia, a fatal disease. This pathogen targets the cytosol of macrophages where it replicates by using the genes encoded in the <em>Francisella</em> pathogenicity island. However, the bacteria are recognized in the cytosol by the host’s ASC/caspase-1 pathway, which is essential for host defense, and leads to macrophage cell death and proinflammatory cytokine production. We used a microarray-based negative selection screen to identify <em>Francisella</em> genes that contribute to growth and/or survival in mice. The screen identified many known virulence factors including all of the Francisella pathogenicity island …

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Induced Biliary Excretion Of Listeria Monocytogenes, Jonathan Hardy, Jeffrey J. Margolis, Christopher H. Contag Feb 2006

Induced Biliary Excretion Of Listeria Monocytogenes, Jonathan Hardy, Jeffrey J. Margolis, Christopher H. Contag

Jeffrey Margolis

Listeria monocytogenes is a ubiquitous gram-positive bacterium that can cause systemic and often lifethreatening
disease in immunocompromised hosts. This organism is largely an intracellular pathogen; however,
we have determined that it can also grow extracellularly in animals, in the lumen of the gallbladder. The
significance of growth in the gallbladder with respect to the pathogenesis and spread of listeriosis depends on
the ability of the bacterium to leave this organ and be disseminated to other tissues and into the environment.
Should this process be highly inefficient, growth in the gallbladder would have no impact on pathogenesis or
spread, but if …

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