Team:Cambridge/Diary/Week 4

Monday

Scandal in the lab! It appears that someone at Caltech has edited our wiki, initially inserting the word 'chicken' into our project page. Then they broke our Java script - potentially accidentally. Easily rectified, but still irritating, especially since the project description deadline was yesterday. Have we been the victim of a not-so-droll ivy league-ish prank? Or is some oddly minded person co-opting this student's account? We've emailed their project supervisor, so hopefully it shouldn't happen again.

One night seems to have been too little time to accurately determine if the transformation worked, as we now have lots of e.coli colonies on the plates. The bacillus plates have not been so successful, but the plasmid was not optimized to bacillus, potentially explaining their failure. We will need to make sure that we include more controls in future to work out where our experiments fail, if they should fail.

In any case, we were able to induce the pBAD promoter with arabinose in the e.coli cells. Results can be seen in the lab book page.

The construct we are hoping to submit to DNA 2.0 has also been partially designed. The fusion of the lux α subunit and the mOrange protein has been completed, as described in the project page (link in when a little more complete). The v.haveyi operon that we are hoping to have codon optimized has also been tided up, with more appropriate spacings between the genes.

Additionally, Andreas managed to finish his Arduino device. It now gives a response that is proportional to the ratio of the light intensities on the two light dependent resistors. By using a couple of coloured filters over the top of these resistors, we can measure the necessary spectral properties of our engineered luciferases. All the engineers need to do now is come up with a user interface.

Tuesday

Apologies from the editing parties at Caltech, apparently the remaining changes were not meant to be there. Unfortunately they also edited Brown's wiki. A storm may be brewing, depending how seriously they take the changes...

Anyway, apart from that little drama, lots happened in the lab today. Jolyon recieved his magnesium ion riboswitch primers - see what we did with them in the lab book. Paul and Andreas also made a short film link about their instrumentation.

Tom worked on making the construct we need to get ordered from DNA 2.0 using their program Gene Designer. He ran into a few issues, but Jim A. was able to give a few hints, and put him into contact with some friendly people in Newcastle who specialize in working with bacillus. If they don't know the answers, no one will.

We're also having some problems deciding what approach to take with the input side of things. Our system should be very flexible, so it would be good to use many different biobricks from the registry. However, very few have been characterized in bacillus. Ideally we would want to find some way of transferring existing biobricks from e.coli so that they were reliable in bacillus, but we may find getting the right sensory proteins into bacillus complex. The idea was floated that we might want to approach the problem as a business problem, and do some market research into what the hypothetical end consumers of our product might want to sense. This would mean pitching to a specific group, potentially obscuring the main point of the project (the breadth and flexibility of the lux based system and its quantitative measurement of concentrations). For example, if we decided to create an agricultural kit as our prototype kit, we would want to create nitrate sensors, iron sensors, osmolarity sensors, fluride sensors etc. However, this would mean leaving out some very interesting additional sensory components. See what we eventually went with on our human practices page link here when we've decided.

Wednesday

The day started with gel electrophoresis of the PCR fragments that were made yesterday. As can be seen in the lab book, our genomic extraction appears to have been successful. However, we haven't managed to make our vector properly. Another day of PCR and gel electrophoresis, I fear...

Prototyping of the hardware that we are hoping to use progressed to foam

Thursday

Friday

Charlie had a brief chat with Dr. Vijayraghavan about potential applications of our project. She offered some useful advice given her proximity to the Bangalore and Caltech teams. See what she had to say in the human practices page link!.

Our bacteria shine ever brighter, with their induction by arabinose creating more successful results than before. In particular, Andreas took them down to the dark room and tested if his electronics were sensitive to the light levels given off by the cultures. And surprisingly enough, it worked! A full 0.10 change in the detected P.D across the LDRs. The change was reliable and reproducible. The only worry is the speed at which light is produced by the bacteria after induction; full luminesence only takes place about 5 hours after the inducing arabinose is added.

Construct design by Tom continued, with the construct for the ratiometric emission by YFP and CFP based upon inducer concentration being made in a couple of hours. Difficulties persist with the construction of the lux operon for bacillus however. There really isn't enough data in the literature to make the RBS's properly.