[Todos] Coloquios del Departamento de Física

[pdmitruk en df.uba.ar]

Recordamos el coloquio de hoy,




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                   COLOQUIOS DEL DEPARTAMENTO DE FÍSICA FCEyN - UBA


                               Charla, café y galletitas
                          En el Aula Federman, 1er piso Pabellón I,
                                  Ciudad Universitaria


           Finding your center: how E. coli utilizes spatiotemporal  
oscillations
                            to select the division site

                   Hoy jueves 26 de noviembre a las 14 hs

                                    KC Huang

                 Stanford University, Department of Bioengineering


In the past decade, fluorescence microscopy has fashioned a new
appreciation for the diversity of ways in which proteins and lipids
organize and segregate on bacterial membranes. Though some targeting
anchors are known, cellular symmetry breaking ultimately requires
molecular components that self-organize. In this talk, I will describe
physical mechanisms for self-organized polar localization. The
remarkable accuracy of cell division in E. coli and related bacteria
is partially regulated by the Min-protein system, which prevents
division near the cell ends by oscillating spatially from pole to
pole. We have developed a model of the Min system, using only known
properties of the proteins, which accurately reproduces the observed
oscillations in both rod-shaped and round cells. In particular, we
have shown that Min-protein oscillations can select the long axis in
nearly round cells, a potentially important factor in division-plane
selection in round bacteria such as Neisseria gonnorhoeae. These
results suggest that oscillations may provide a general mechanism by
which proteins can localize in response to features of cell geometry
incapable of localizing individual molecules.