Team:BCCS-Bristol/Calendar-Main/2 July 2008

Meeting: Weekly Status Meeting

Time: 4:00pm - 5:00pm

Location: BCCS Office

Agenda

• Presentation about previous iGEM projects related to chemotaxis.
• Update on the current modelling.
• Discussion about mechanics based simulation.
• Task list and allocations
• AOB

Attendees

Summary

1. Previous iGEM Projects (Slides USCF & Cambridge, Rice, Modelling):
   • UCSF 2006 - Produced orthogonal CheW/CheW* to allow chemoattractant to be selected. Bacteria strain UU1250 (Parkinson Lab) was used with the CheW knocked out. The reason for picking CheW was this it is a fairly small protein which would hopefully degrade quickly (could also be tagged) allowing switching to occur quickly. Parts for each receptor are available, but the success of the project is not known.
   • Cambridge 2006 - Was a large project where bi-directional cell signalling was implemented to produce ordered patterns in RFPs and GFPs. They used performed motility test and found that MC1000 and MG1655 (Suggested by Nigel) performed well. They contributed parts for quorum sensing that have been shown to work successfully.
   • Rice 2006 - Used chemotaxis toward B.subilis pheromones to collate around a colony and when enough bacteria present produce a lethal substance. Used the RP8611 E.coli strain which has null MCP receptors.
   • Harvard 2007 - These appear to have considered the idea of coating particles with proteins that stick to membrane proteins on the bacteria. Once enough bacteria are present (quorum sensing) a light signal is produced. Also, because beads are magnetised the bacteria can then be moved around. Unfortunately, the full project could not be evaluated so further work needs to be performed.
2. The modelling of the chemoattractant switch is underway and the mathematics and simulation has been completed. Unfortunately, no actual parameter values have been found yet so estimates were entered. These showed that the switch seems to work as expected only expressing a single CheW/CheW* as required. Parameters need to be found for each variable, however, a more pressing matter was ensuring that a mechanics based simulation was produced to evaluate how well the method we are proposing will work.
3. During the questions session several important points were made. The first was that the movement that a bacteria will make will be a biased random walk and as such it may not impart the full force possible on the particle to move. This may not be such a problem if recruitment can cause swarming behaviour around the particle allowing for a mean force of the group to be imparted, however, simulations should be produced to evaluate this. Secondly, if the forces are less than initially anticipated, it will be important to damp any external influences and so vibration free tables may be necessary. This can be evaluated after the feasibility study.

Actions

• (Jenn, Sophie W, Joe, Rodger) Continue to research the Harvard 2007 project, and collate all from projects that would be suitable to use.
• (Ian, Sophie W, Sophie A, Tom G) Start to research and develop mechanics based model for the project.
• (Tom G, Ghizzi, Maria) Start work in the lab carrying out feasibility studies.