Formal Lab Session - 17th September 2009

Stochastic switch team

Today we ran the minipreps for sac and ara transformed cells however- perhaps due to poor miniprep procedure- the sac test digest yeilded poor results, however the ara transformants miniprep gave a ~200bp band along with the backbone in 8/12 lanes:

Midi prep cultures were set up using cultures corresponding to lanes 1 and 3 for ara.

To test whether the poor sac result was due to the miniprep more miniprep cultures were set up to do tomorrow.

Today also we did fragment preps for Goksels sspb the ara fragment, and a cwlJ fragment for Hanny:

Metal Sensing Team

Introduction

In yesterday's lab session the Metal Sensing team carried out mini-preps on the 12 colonies of potential cotC-GFP-smtA E. coli transformants and analysed them. Despite them showing incorrectly sized bands when digested and ran on gel, the team proceded to carry out preparations to midi-prep colony 8 on the basis of consistency of the band patterns and the theory that the digests may not have worked properly. The midi-prep will be done today.

The team also prepared to ligate the cadA promoter to the BBa_J33206 BioBrick (which contains the arsR gene and arsR binding site and has the promoter cut out) but only got as far as digesting the two fragments. The cadmium-sensor has been put on hold as of the General Meeting on 16/09/09.

Additionally the metal sensing team prepared for transformation in Bacillus subtilis by carrying out the evening steps of the protocol - this will mean that if the midi-preps are a success then B. subtilis can be transformed with cotC-GFP-smtA in pMUTIN4 today!

Today's lab work will focus on midi-prepping colony 8 (which is a potential cotC-GFP-smtA transformant E. coli colony). The DNA will then be analysed by digesting a sample with BamHI and HindIII and running it on agarose gel through DNA gel electrophoresis. If successful, the DNA will be used to transform B. subtilis cells; if unsuccessful the ligations of pMUTIN4 to cotC-GFP-smtA will have to be repeated on another day.

Practical Outline

The tasks the Metal Sensing team hope to carry out by the end of the day include the following:

Midi-prep colony 8 of the potential cotC-GFP-smtA transformant E. coli DH5-alpha cells.
Digest the midi-prepped DNA with BamHI and HindIII
Analyse the digested products through DNA gel electrophoresis:
1. If successful, use midi-prepped DNA to transform Bacillus subtilis
2. If unsuccessful, prepare to carry out a second attempt at ligating cotC-GFP-smtA to pMUTIN4.

Procedure

1) Midi-prep of potential cotC-GFP-smtA transformant E. coli cells

To carry out the midi-prep we used Sigma-Aldrich's GenElute HP Midi-prep kit (and the protocol attached to it). We conducted steps 1-6 and then steps 7b to 11b (the Spin Method) followed by the DNA concentration step. There was only one major change to the protocol:

For the DNA concentration step instead of transferring the eluted DNA to one centrifuge tube, the DNA was transferred into two Eppendorf tubes. This change means that we now have access to a centrifuge capable of reaching 13,000rpm; if we had stuck to using the centrifuge tubes described in the protocol then we wouldn't be able to reach the required g-force.

Once the midi-prep process was completed the DNA was placed in the -20ºC freezer.