On the expansion of bacteria through soft agar
Condensed Matter lunchtime seminar
On the expansion of bacteria through soft agar
- Event time: 1:00pm
- Event date: 30th April 2007
- Speaker: Ottavio Croze (University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Event details
Agar is a polysaccharide gel derived from
seaweed which is routinely used for the culture of bacteria. Growth
plates consist of a nutrient broth mixed with high concentrations of
agar (10-20 g/litre) resulting in a 'hard' gel on which bacterial
colonies grow. When investigating the swimming and chemotactic**
behaviour of bacteria it is however customary to use 'soft' low
concentration (1-3.5 g/litre) agar gels. In such 'motility assays'
the centre of soft agar Petri dishes is seeded with a drop of
bacterial culture and incubated at constant temperature. The initial
bacterial colony then expands across the plate producing stunning
patterns. Biologically, the spreading is an easy way to assess
motile dysfunction; further, the spatial separation afforded by the
spreading allows to select for more or less motile/chemotactic
bacteria. Physically, however, one would like to find out how the
spreading occurs in the first place. In particular, given that the
bacteria have to make their way through a gelatinous network, what
is the influence of the agar concentration on the colony expansion
speed? I will discuss possible answers suggested by the results of
macroscopic experiments I have performed, as well as some very
preliminary microscopic investigations.
**chemotaxis: the ability of bacteria to direct their motion towards chemically favourable environments (and away from toxic ones!).
**chemotaxis: the ability of bacteria to direct their motion towards chemically favourable environments (and away from toxic ones!).
About Condensed Matter lunchtime seminars
This is a weekly series of informal talks given primarily by members of the institute of condensed matter and complex systems, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..