Team:Imperial College/B.subtilis

Throughout this summer we worked with B. subtilis as a chassis. Although it has great potential, it is not commonly used and very few BioBricks are available for it; as part of our project we aimed to increase subtilis's accessibility as a chassis. The major results of our work are summarised on this page, and it is also summarised on the new B. subtilis chassis page on the Registry of Biological Standard Parts.

In order to pursue our project we had to design and build a variety of BioBrick parts for B. subtilis. These can be split up into three groups:

• Promoter and Ribosome Binding Sites (RBS) - These promoter and RBS combinations include a number of inducible and constitutive promoters combined with weak and strong ribosome binding sites.
• Coding Regions - These parts include specific coding regions concerned with our project such as biomaterials, and more general coding regions such as antibiotic resistance genes that can be used for selection markers.
• Integration Sites - As an alternative to maintaining genetic devices on extra-chromosomal plasmids we investigated the construction of parts to allow integration of genetic devices into the B. subtilis chromosome.

In order to expand the use of B. subtilis as a potential chassis we investigated the different protocols used for the transformation of B. subtilis. B. subtilis is used as the model for gram positive bacterium and have been extensively studied. A variety of protocols have been developed for the transformation of B. subtilis. We investigated two different protocols, one relying upon natural competence of stressed B. subtilis and the other using electroporation. The protocols and results were both fully documented to further the use of B. subtilis as a chassis - The protocols can be found in the wet lab section (transformation 1 & 2), and you can click "Details" below to see the results of the transformation.

>>> Details >>>

Growth Curve

We characterised the growth rate of B. subtilis in LB media at 37^oC. This curve provides useful information when inducing protein synthesis in B. subtilis and when characterising parts such as promoters. In addition to collecting this growth curve information, we modelled the growth rate of B. subtilis which can be found in the Growth Curve section of the Dry Lab.

Motility

We also went some way toward characterising the motility of the chassis but more detailed information on that side of the chassis characterisation can be found on the Major Results page and the motility section of the dry lab.