Cell-Cell Signaling in Archaea: How <em>Haloferax volcanii </em>Talk to Each Other Priyanka Chatterjee

Format:

Book

Thesis/Dissertation

Author/Creator:

Chatterjee, Priyanka, author.

Contributor:

University of Pennsylvania. Cell and Molecular Biology., degree granting institution.

Language:

English

Subjects (All):

0287.

0306.

0379.

0410.

Local Subjects:

0287.

0306.

0379.

0410.

Physical Description:

1 electronic resource (200 pages)

Contained In:

Dissertations Abstracts International 87-07B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2025

Language Note:

English

Summary:

Archaea play crucial roles in global geochemical cycles, have increasing promise for biotechnological applications, and are found in many diverse environments. However, little is known about many fundamental biological processes of archaea, such as their intra- or interspecies communication, leaving much unknown about this domain of life. Quorum sensing (QS) is a population density-dependent form of microbial communication. The model archaeon Haloferax volcanii displays distinct morphologies across population densities: cells in culture at early-log phase are rod-shaped while cells in late-log phase are pleomorphic disks. Our studies reveal that applying cell-free conditioned medium (CM) from a late-log culture to a fresh Hfx. volcanii culture results in exclusively disk-shaped cells at early-log phase and a lack of motility. These results enabled us to establish a robust system for studying QS in archaea. Using this system, we determined that the regulatory proteins DdfA and CirA are involved in the Hfx. volcanii QS response pathway, because the corresponding deletion mutants do not display the QS-mediated morphology and motility changes. Combining these phenotypic observations with quantitative proteomics, we identified an extensive set of proteins differentially abundant in response to CM. We then pioneered a high-throughput flow-cytometry based method to distinguish between the Hfx. volcanii rods and disks, enabling us to conduct a genetic screen to identify genes part of the biosynthesis pathway of the QS signal. We identified the cytochrome P450 cyc2 and the molybdopterin synthase large subunit homolog moaE as involved in signal production. Furthermore, we characterized the QS signal to be an amphipathic small molecule and optimized an efficient extraction and purification method. We also indicate the potential for interspecies and inter-domain crosstalk: another haloarchaeal species can produce the Hfx. volcanii QS signal, and CM from Hfx. volcanii can activate a bacterial QS bioreporter. Finally, we identified key residues of two biosynthetic components of the archaeal flagella important for a novel form of motility regulation and determine that CirA is a master regulator of motility. These discoveries of archaeal QS and the collective coordinated behaviors influenced by population density significantly advance our understanding of microbial communication and the regulatory networks governing QS-mediated phenotypes

Notes:

Advisors: Pohlschröder, Mechthild Committee members: Zhu, Jun; Goulian, Mark; Zackular, Joseph; McCallum, Monica; Miyashiro, Tim

Source: Dissertations Abstracts International, Volume: 87-07, Section: B.

Ph.D. University of Pennsylvania 2025

Vendor supplied data

Local Notes:

School code: 0175

ISBN:

9798276001586

Access Restriction:

Restricted for use by site license