All Events

Seminar
Tuesday, February 28, 2017   |   through Tuesday, February 28, 2017   |   4pm   |   T-639   |   Speaker: Igor Brodsky, Ph.D.   |   Host: Dr Ferric Fang
Journal Club
Friday, March 3, 2017   |   through Friday, March 3, 2017   |   9:30am
Seminar
Tuesday, March 7, 2017   |   through Tuesday, March 7, 2017   |   4pm   |   T-639   |   Speaker: Yves Brun, Ph.D.   |   Host: Dr Sam Miller

The diversity of shapes of organisms is one of the most fascinating aspects in the field of biology. While bacteria display a myriad of morphologies, the mechanisms that control morphogenesis and the evolution of bacterial morphology are not well understood. One mechanism that drives morphogenesis is the synthesis of peptidoglycan (PG) at specific subcellular sites, or zones. For example, zonal PG synthesis drives the formation of appendage-like extensions of the cell envelope called stalks at distinct sub-cellular positions in alphaproteobacteria, polar in the genus Caulobacter, subpolar in Asticcacaulis excentricus, and bilateral in Asticcacaulis biprosthecum. The SpmX developmental regulator of C. crescentus acquired a new function to drive stalk PG synthesis at subpolar and bi-lateral sites in the Asticcacaulis genus (1). Time-lapse microscopy analysis shows that SpmX initially localizes to a subpolar position in both A. biprosthecum and A. excentricus, where it remains static. Cell elongation in A. excentricus occurs mostly from the septum, and SpmX localization remains subpolar where it drives stalk synthesis. In stark contrast, A. biprosthecum cells elongate from the pole where SpmX is localized, ultimately yielding a cell where SpmX is localized laterally. Most alphaproteobacteria elongate polarly (2), whereas C. crescentus elongates mostly from the septum (3). Fluorescent D-amino acid labeling of areas of PG synthesis (4) in four genera of the Caulobacterales indicated that polar elongation was lost in this group, but reappeared in the more recently evolved A. biprosthecum. We hypothesize that it is the reappearance of a lost ancestral polar growth mode, rather than the targeting of SpmX to a new site, that led to the evolution of lateral stalk synthesis in A. biprosthecum. I will also summarize our recent use of FDAAs to directly analyze the spatio-temporal dynamics of peptidoglycan synthesis at the site of cell division in Bacillus subtilis and its correlation with the activity and dynamics of cytoskeletal and peptidoglycan synthesis proteins, revealing key aspects of their coordination. These studies have for the first time determined the connection between cytoskeletal proteins, peptidoglycan synthesis enzymes, and spatiotemporal patterns of peptidoglycan synthesis at the cell division site, revealing a key role for FtsZ treadmilling in guiding the progressive insertion of new cell wall, building increasingly smaller concentric rings of peptidoglycan to divide the cell (5).

 

 

1. Jiang, C., 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, 489-93.

2. Brown, P.J.B., M.A. de Pedro, D.T. Kysela, C. Van der Henst, J. Kim, X. De Bolle, C. Fuqua, and Y.V. Brun. 2012. Polar growth in the Alphaproteobacterial Order Rhizobiales. PNAS, 109: 1697-1701.

3. Aaron, M., Charbon, G., Lam, H., Schwarz, H., Vollmer, W., Jacobs-Wagner, C. 2007. The tubulin homologue FtsZ contributes to cell elongation by guiding cell wall precursor synthesis in Caulobacter crescentus. Molecular Microbiology, 64: 938-52.

4. Kuru, E., H.V. Hughes, P.J.B. 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. Angewandte Chemie, 51(50):12519-23.

5. Alexandre W. Bisson Filho*, Yen-Pang Hsu*, Georgia R. Squyres*, Erkin Kuru*, Fabai Wu, Calum Jukes, Cees Dekker#, Seamus Holden#, Michael S. VanNieuwenhze#, Yves V. Brun#, and Ethan C. Garner#. Treadmilling by FtsZ filaments drives peptidoglycan synthesis and bacterial cell division. Science, http://dx.doi.org/10.1126/science.aak9973. * co-first authors, #co-corresponding authors.

Journal Club
Friday, March 10, 2017   |   through Friday, March 10, 2017   |   9:30am
Seminar
Tuesday, March 14, 2017   |   through Tuesday, March 14, 2017   |   4pm   |   TBD   |   Speaker: Dr Tania Baker
Departmental Event
Wednesday, March 15, 2017   |   through Wednesday, March 15, 2017   |   12pm
Journal Club
Friday, March 17, 2017   |   through Friday, March 17, 2017   |   9:30am   |   TBD   |   Speaker: First year students

Rotation Talks

Other
Monday, March 20, 2017   |   through Friday, March 24, 2017
Seminar
Tuesday, March 28, 2017   |   through Tuesday, March 28, 2017   |   4pm   |   T-639   |   Speaker: Dr Alexander Horswill   |   Host: Dr Ferric Fang
TBD
Seminar
Tuesday, April 4, 2017   |   through Tuesday, April 4, 2017   |   4pm   |   T-639
Seminar
Tuesday, April 11, 2017   |   through Tuesday, April 11, 2017   |   4pm   |   T-639
Seminar
Tuesday, April 18, 2017   |   through Tuesday, April 18, 2017   |   4pm   |   T-639   |   Host: Department of Microbiology Graduate Students
Seminar
Tuesday, April 25, 2017   |   through Tuesday, April 25, 2017   |   4pm   |   T-639   |   Speaker: John D. MacMicking, Ph.D   |   Host: Dr Josh Woodward
Journal Club
Friday, April 28, 2017   |   through Friday, April 28, 2017   |   9:30am
Seminar
Tuesday, May 2, 2017   |   through Tuesday, May 2, 2017   |   4pm   |   T-639   |   Host: Dr Beth Traxler
Seminar
Tuesday, May 9, 2017   |   through Tuesday, May 9, 2017   |   4pm   |   T-639   |   Host: Dr Evgenni Sokurenko
Journal Club
Friday, May 12, 2017   |   through Friday, May 12, 2017   |   9:30am
Seminar
Tuesday, May 16, 2017   |   through Tuesday, May 16, 2017   |   4pm   |   T-639   |   Host: Dr Joseph Mougous
Departmental Event
Monday, May 22, 2017   |   through Monday, May 22, 2017   |   5pm
Seminar
Tuesday, May 23, 2017   |   through Tuesday, May 23, 2017   |   4pm   |   T-639   |   Host: Dr Carrie Harwood
Seminar
Tuesday, May 30, 2017   |   through Tuesday, May 30, 2017   |   4pm   |   T-639   |   Host: Dr Pradeep Singh
TBD
Seminar
Tuesday, June 6, 2017   |   through Tuesday, June 6, 2017   |   4pm   |   T-639
Journal Club
Friday, June 9, 2017   |   through Friday, June 9, 2017   |   9:30am   |   TBD

Rotation talks