Bassler Lab Members

Bassler Lab Team

Bassler Lab Team

Principal Investigator

Bonnie Bassler
Bonnie L. Bassler
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Research Interest:  Cell-to-cell communication in bacteria.
Bonnie L. Bassler Biography »

Curriculum Vitaepdf-icon-25x25


Postdoctoral Fellows

 
Nina Hoyland-Kroghsbo
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Research Interest: The global threat of multi-drug resistant bacteria urgently demands alternatives to conventional antibiotics. Two promising alternatives to traditional antibiotics are bacteriophage (phage) therapy and inhibitors of bacterial cell-cell communication, known as quorum sensing (QS). Bacteria in high cell density maximally engage in QS. These cells are particularly vulnerable to phage infections, which could rapidly spread and kill the population. QS-control of antiphage activities would enable bacteria to specifically activate defenses when they are at the highest risk of infection. I am investigating to what extent bacteria use QS to regulate their antiphage defenses. Whereas QS-inhibitory compounds are generally studied for their capacity to inhibit bacterial virulence, I will study whether they additionally have the ability to increase the vulnerability of pathogenic bacteria to phages.

Anisa
Anisa Ismail

Research Interest: Intestinal epithelial cells provide the crucial interface (400 m2) between mammalian hosts and a vast consortium of microbial partners. Yet, little is known about the mechanisms regulating our beneficial relations with commensal bacteria.  The fact that bacteria and mammalian intestinal cells are in constant contact with one another, combined with the universal use of intercellular communication in prokaryotes and eukaryotes, has led me to speculate that  bacteria- and/or mammalian-secreted signals are involved in maintaining homeostasis via intra- and inter-kingdom communication.  I am investigating these ideas by studying Bacteroides fragilis-eukaryotic cell interactions in a mouse model.  B. fragilis is a prominent member of the normal gut microflora that plays a vital role in maintaining intestinal health by directing host anti-inflammatory responses. However, the mechanisms underlying these interactions are not known.  Anisa's ongoing studies in the lab will focus on how resident gut bacteria influence intestinal health through quorum sensing behaviors, and I will characterize quorum sensing factors directing collective behaviors in B. fragilis.


 
Sampriti Mukherjee
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Research Interest: Quorum sensing (QS) regulates biofilm development in various bacteria and biofilms play crucial role in bacterial infections as well as clog filters and reactors in industries. Sampriti investigates the spatio-temporal regulation of QS during biofilm development in realistic environments using microfluidics, live cell-imaging and genetic tools. Designing successful synthetic strategies to inhibit or to enhance biofilms in clinical or industrial settings hinges on our understanding of how quorum sensing controls biofilm development.

 
Jon Paczkowski
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Research Interest: We are at a pivotal point in modern health care due to the presence and proliferation of antibiotic resistance in various pathogenic bacteria.  P. aeruginosa is an important pathogen that affects cystic fibrosis patients as well as the immunocompromised, such as cancer patients receiving chemotherapy.  It has a well-defined quorum sensing (QS) network that is directly linked to biofilm formation and virulence.  I am interested in understanding the molecular mechanism of small molecule activation and inhibition of the two main QS receptors, LasR and RhlR.  I am taking a biochemical and biophysical approach to understand how these receptors bind small molecules, how they are activated, and how their function can be modified to modulate the QS network thereby altering virulence and pathogenesis. 

Kai
Kai Papenfort

Research Interest: Quorum sensing (QS) controls the expression of hundreds of genes in each cell, yet it is not understood how these genes are simultaneously controlled nor whether regulation is identical in all cells in a population. Kai uses deep-sequencing technologies and fluorescent microscopy to investigate gene expression changes in populations and in individual cells undergoing QS to discover the regulatory players and mechanism that drive collective behaviour.


 
Jing Yan
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Research Interest: Many bacteria have the amazing ability to switch between different lifestyles, between living in the fluid and dwelling in a biofilm. This flexible strategy presumably increases their competence in a fluctuating environment. Using V. cholerae as the model organism and combing microscopy, microfluidic, and genetic tools, I am testing this ecological hypothesis that is naturally linked to the infectious cycle of V.cholerae. At the same time, I am uncovering the molecular mechanism of the less understood dispersal process. By developing fluorescent reporters, I wish to observe the spatial heterogeneity in the gene expression within a biofilm, which will reveal how the complicated processes of biofilm formation and disintegration are actively controlled, both spatially and temporally.

Graduate Students

Amanda Hurley
Amanda Hurley
 
Research Interest: The autoinducer CAI-1 is produced, secreted and sensed by the transmembrane histidine kinase CqsS in Vibrio cholerae. CAI-1-mediated signaling induces quorum sensing and consequently represses virulence factors such as TCP and CTX. I am interested in the artificial activation of quorum sensing in V. cholerae using small molecules, which target either CqsS or the downstream transcription factor LuxO. I want to identify the mechanism by which these pro-quorum sensing molecules inhibit the CqsS and LuxO, which will illuminate how two-component signal transduction occurs in V. cholerae. In addition, these small molecules have the potential to be developed into therapeutics for the disease cholera.

 Xiaobo
Xiaobo Ke
 
Research Interest: LuxN is a membrane-bound receptor for acyl-homoserine lactone (AHL) autoinducers. The molecular interaction between AHL and luxN remain elusive because of lack of structural information about LuxN. I want to exploit AHL homologs and other LuxN antagonists to study their interactions with LuxN using genetics. In addition, I am interested in how the receptor respond to mixture of signals in vivo, which will be helpful for interfering quorum-sensing.

 
 Minyoung Kevin Kim
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Research Interest: In natural habitats and in industrial and medical settings, bacteria commonly live adhered to surfaces in biofilms and are exposed to fluid flow. QS controls biofilm formation, however it is not known how QS functions under constant or intermittent (e.g. pulsatile) flow, or how QS and biofilm formation vary as a function of position along a flow, nor is it known how surface topography impact QS-mediated communication in flow. In addition, it is also unknown how QS within biofilm formation vary as a function of depth in flow. Kevin explores these questions using Staphylococcus aureus and Vibrio cholerae; two pathogens in which QS regulates virulence. Understanding the ramifications of these spatially and temporally non-uniform QS responses will be crucial for successful deployment of synthetic pro- and anti-QS strategies to enhance beneficial bacteria and to combat harmful bacteria in medicine and industry.

 
Amelia McCready
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Research Interest: For the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing plays a pivotal role in pathogensis. The two main quorum sensing systems LasI/R and RhlI/R regulate a large portion of the genome and control the production of many virulence factors. However, there is much yet to learn about these two systems and their targets. I am working on identifying and characterizing inhibitors of the receptors LasR and RhlR. I am also interested in investigating how these inhibitors will effect P. aeruginosa biofilms and in vivo infections. Finally, I hope to use these inhibitors as tools to understand more about how LasR and RhlR function: including how they form homodimers, interact with DNA and interact with RNA polymerase.

 
Alice Min
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Research Interest: At the heart of the Vibrio harveyi quorum sensing (QS) circuit lie five homologous small RNAs (sRNAs), Qrr 1-5 (quorum regulatory RNAs). The Qrr sRNAs control the levels of AphA and LuxR, the master low cell density (LCD) and high cell density (HCD) QS regulators, respectively. Hence, the Qrrs are key dictators of whether V. harveyi will engage in individual or group behavior. Given the critical role that the Qrr sRNAs play in QS, I am investigating whether there exist additional sRNAs that influence QS. Using high-throughput whole genome microarrays and RNA-sequencing, the Bassler group recently discovered dozens of intergenic sRNAs in V. harveyi, which could play roles in QS. I study one of these sRNAs, QsrA (quorum sensing-regulated sRNA A), which exhibits more than 30-fold gene expression change between LCD-locked and HCD-locked V. harveyi strains. I investigate the mechanism of QsrA regulation, the targets QsrA itself regulates, and the biological role of QsrA. My characterization of QsrA will elucidate finer details of the V. harveyi QS circuit and could lead to novel ways to manipulate QS-mediated behaviors, such as biofilm production and virulence, in V. harveyi and possibly other Vibrio species.

 

Undergraduate Students

 
Lynessa McGee
 

 
Deirdre Ricaurte
 

  Emily Wohl  

Research Associates

jian-ping
Jian-Ping Cong
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Julie Valastyan
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Lab Specialist

Ed
Ed Kennedy
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Faculty Assistant

Jennifer Munko
Jennifer Munko
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P (609) 258-5659

 


Collaborators

Fred Hughson
Fred Hughson
Princeton University, Molecular Biology
Hughson Lab

 


Semmelhack
Martin Semmelhack
Princeton University, Chemistry

 


Howard Stone
Howard Stone
Princeton University, Mechanical and Aerospace Engineering
Stone Lab

 


Ned Wingreen
Ned Wingreen
Princeton University, Molecular Biology
Wingreen Lab