Assistant Professor of Biological Sciences
PhD, 2006 University of Georgia
Molecular basis for polar growth in Agrobacterium tumefaciens
Research descriptionPOSITIONS AVAILABLE:
Postdoctoral scholar, graduate student, laboratory technician, and undergraduate student positions available now. Email resume to firstname.lastname@example.org
My lab is interested in understanding the principles that govern bacterial morphology, a readily observable facet of microbial cell biology. One of the major unsolved questions in microbiology is how bacteria generate specific shapes. Bacteria exhibit an amazing diversity of shapes and sizes that are precisely reproduced at every generation, indicating that morphology plays an important role in the life of these bacteria (Figure 1). Impressive progress has been made in the past few years in understanding the mechanism of cell shape determination in a few model bacterial systems, including the discovery that bacteria possess a cytoskeleton, but we are still very far having a comprehensive understanding of how bacterial morphologies are generated. My lab takes advantage of recent technical advances in microscopy, construction of fluorescent fusion proteins, and high throughput sequencing, to make strides in understanding how bacteria generate specific morphologies.
In most bacteria, the cell wall is comprised of peptidoglycan and is a major determinant of cell shape. In a majority of rod-shaped bacteria, including E. coli, cells elongate by the lateral insertion of newly synthesized peptidoglycan along their sidewalls. In contrast, some rod-shaped bacteria utilize precise targeting of peptidoglycan to specific polar locations to enable cell elongation. Indeed, we have previously shown that constrained polar growth is responsible for elongation in many species of Rhizobiales, including Agrobacterium tumefaciens (Figure 2). My lab uses A. tumefaciens, a well-studied plant pathogen and causative agent of crown gall disease, as a model to understand how bacteria constrain peptidoglycan synthesis to specific cellular localizations. Presently, we are focused on addressing two key questions:
What is the mechanism underlying polar growth of A. tumefaciens?
What are the ecological and evolutionary benefits imparted by polar growth?
Knowledge gained though these studies will then be applied to enhance our understanding of the precisely targeted growth in other Alphaproteobacteria, including those that display remarkable morphologies. Our goal is to better understand the role of zonal peptidoglycan synthesis in generating both relatively simple and dramatically complex bacterial shapes.
Howell, M., Aliashkevich, A., Salisbury, A.K., Cava, F., Bowman, G.R., Brown, P.J.B. Absence of the polar organizing protein PopZ results in reduced and asymmetric cell division in Agrobacterium tumefaciens (2017) Journal of Bacteriology, 199 (17), art. no. e00101-17,
H. Attai, J. Rimbey, G.P. Smith, and P.J.B. Brown. 2017. Expression of a peptidoglycan hydrolase from lytic bacteriophages Atu_ph02 and Atu_ph03 triggers lysis of Agrobacterium tumefaciens. Appl Environ Microbiol. 83:e01498-17.
M. Howell, J.J. Daniel, and Pamela J.B. Brown. 2017. Live cell fluorescence microscopy to observe essential processes during microbial cell growth. J Vis Exp. 129:e56497.
Howell, M., Brown, P.J. Building the bacterial cell wall at the pole (2016) Current Opinion in Microbiology, 34, pp. 53-59.
Figueroa-Cuilan, W., Daniel, J.J., Howell, M., Sulaiman, A., Brown, P.J.B. Mini-Tn7 insertion in an artificial attTn7 site enables depletion of the essential master regulator ctrA in the phytopathogen agrobacterium tumefaciens (2016) Applied and Environmental Microbiology, 82 (16), pp. 5015-5025.
Williams, M., Hoffman, M.D., Daniel, J.J., Madren, S.M., Dhroso, A., Korkin, D., Givan, S.A., Jacobson, S.C., Brown, P.J.B. Short-stalked Prosthecomicrobium hirschii cells have a Caulobacter-like cell cycle (2016) Journal of Bacteriology, 198 (7), pp. 1149-1159
M.A. Williams*, M.D. Hoffman*, J.J. Daniel, S.M. Madren, A. Dhroso, D. Korkin, S.C. Jacobson, and P.J.B. Brown. 2016. Short-stalked Prosthecomicrobium hirschii cells have a Caulobacter-like cell cycle. J Bacteriol. 198: 1149-1159.
Hoffman, M.D., Zucker, L.I., Brown, P.J.B., Kysela, D.T., Brun, Y.V., Jacobson, S.C. 2015. Timescales and Frequencies of Reversible and Irreversible Adhesion Events of Single Bacterial Cells. Analytical Chemistry, 87(24):12032-12039.
C. Jiang, P.J.B. Brown, A. Ducret, and Y.V. Brun. 2014. Sequential evolution of bacterial morphology by co-option of a developmental regulator. Nature, 506(7489):489-493.
D.T. Kysela, P.J.B. Brown, K.C. Huang, Y.V. Brun. 2013. Biological Consequences and Advantages of Asymmetric Bacterial Growth. Annu Rev Microbiol. 67: 417-435.
A. Sims, Y. Zhang, S. Gajaraj, P.B. Brown, and Z. Hu. 2013. Towards the development of microbial indicators for wetland assessment. Water Res. 47:1711-1725.
Z. Wan, P.J.B. Brown, E.N. Elliott, and Y.V Brun. 2013. The adhesive and cohesive properties of a bacterial polysaccharide adhesion are modulated by a deacetylase. Mol Microbiol. 88:486-500.
S.M. Madren, M.D. Hoffman, P.J.B. Brown, David T. Kysela, Yves V. Brun, and Stephen C. Jacobson. 2012. Microfluidic device for automated synchronization of bacterial cells. Analytical Chemistry, 84(20):8571-8578.
V.R. Pejaver, J. An, S. Rhee, A. Bhan, J.-H. Choi, B. Liu, H. Lee, P.J. Brown, D. Kysela, Y.V. Brun, and S. Kim. 2012. GeneclusterViz: a tool for conserved gene cluster visualization, exploration, and analysis. Bioinformatics 28(11):1527-1529.
P.J.B. Brown, M.A. DE Pedro, D.T. Kysela, C.V.d. Henst, X. DeBolle, C. Fuqua, and Y.V. Brun. 2012. Polar growth in Alphaproteobacteria. Proc Natl Acad Sci. 109(5):1697-1701.
E. Kuru, H.V. Hughes, P.J. Brown, E. Hall, S. Tekkam, F. Cava, M.A. de Pedro, Y.V. Brun, and M.S VanNieuwenhze. 2012. In situ probing of newly synthesized peptidoglycan in live bacteria with fluorescent D-amino acids. Angew Chem. 51:12519- 12523.
G. Li, P.J.B. Brown, J.X. Tang, J. Xu, E.M. Quardokus, C. Fuqua and Y.V. Brun. 2011. Surface contact stimulates the just-in-time deployment of bacterial adhesions. Mol Microbiol. 83(1):41-51.
Chertkov, O., Brown, P.J., Kysela, D.T., de Pedro, M.A., Lucas, S., Copeland, A., Lapidus, A., del Rio, T.G., Tice, H., Bruce, D., et al. 2011. Complete genome sequence of Hirschia baltica type strain (IFAM 1418 T). Standards in Genomic Sciences, 5(3):287-297.
P.J.B. Brown, D.T. Kysela, and Y.V. Brun. 2011. Polarity and the diversity of growth mechanisms in bacteria. Semin Cell Dev Biol. 22(8):790-798.
P.J.B. Brown, D.T. Kysela, A. Buechlein, C. Hemmerich, and Y.V. Brun. 2011. Genome sequences of eight morphologically diverse Alphaproteobacteria. J. Bacteriol. 193:4567-4568.
M.L. Kovarik, P.J.B. Brown, D.T. Kysela, C. Berne, A.C. Kinsella, Y.V. Brun, and S.C. Jacobson. 2010. Microchannel-Nanopore Device for Bacterial Chemotaxis Assays. Anal Chem 82:9357–9364.
G.G. Hardy, R.C. Allen, E. Toh, M. Long, P.J.B. Brown, J.L. Cole-Tobian, Y.V. Brun. 2010. A localized multimeric anchor attaches the Caulobacter holdfast to the cell pole. Mol Microbiol. 76:409-427.
Honors & Awards
Selected honors and awards
Mr. & Mrs. Shouson & Yunying-Kou Jen Junior Faculty Research Award in Biology 2017
Provost’s Outstanding Junior Faculty Teaching Award 2016
College of Arts and Science Purple Chalk Teaching Award 2015
Ruth L. Kirschstein National Research Service Award Postdoctoral Fellowship 2007
University of Georgia Outstanding Graduate Research in Life Sciences Award 2006
University of Georgia Outstanding Teaching Assistant Award 2004
Joy Williams Porter Graduate Fellowship Recipient 2003
Achievement Rewards for College Scientists (ARCS) Fellowship Recipient 2002
University of Georgia Presidential Fellow 2000
Jan. 23, 2017
Recipients of 2017 Faculty Fellow Awards in Biological Sciences announced
Sept. 21, 2016
Brown lab awarded NSF grant to study cell growth in a pathogenic soil bacterium
Feb. 24, 2015
Biology Takes Home Several Arts and Science Awards
April 22, 2014
Seven from biology take home awards at 2014 Life Sciences Week
Jan. 23, 2014
New study unravels mystery of cell shape diversity in bacteria
May 20, 2013
Pamela Brown’s photo voted “Most Popular” in contest
Nov. 16, 2012
Topics Course on Symbiotic Microbial-Host Interactions (BIO_SC 8002-01) (Spring 2013)