Transilluminators are especially useful to see DNA bands on a gel. While there is an old upcycled imager in the P1, this has detector problems, so sometimes much of the gel is not even visible... Therefore, we have been trying out new 'DIY-transilluminators' with a little help from some Hackteria friends and others (htgaa)!
Urs brought his GaudiLabs kit to Hackuarium on 2dec, and he helped Rachel do the soldering and put it all together.
The design file is freely available, as is the LED circuit board design.
To note: There are many other cute generic lab equipment kits that he has available via his Gaudi Labs!
This blue transilluminator definitely could use a diffuser of some sort to help avoid seeing the whole circuit board below, and the circuit board itself fluoresces in this blue LED light, which is an unsolved problem that Urs is looking into further.
The first five pictures in the gallery show various stages of the process of soldering the components and the fluorescence of the board itself.
Dan also ordered bigger filters and a string of bright blue LEDs to try making a new 'midi' size transilluminator, soon!
11dec17 gel - second PTC PCR test
The chemical PTC can be tasted or not tasted, depending on a GC polymorphism in the TAS2R38 bitter taste receptor.
Primers for this test and the protocol were obtained from Delphine Ducoulombier of l'Eprouvette.
Originally, these are based on a Cold Spring Harbour lab test (in their DNA Learning Center). Q5 polymerase was used for the amplification, and DNA from Sam (a non-taster) and Rachel (a taster) was used for the test. The DNA was a quick GnG prep that had been concentrated by pptn, after apparently no product was obtained the first PCR attempt, (but Rachel's sample had less DNA than Sam's... also less cells to start!). Stages of looking at the first gel (2% agarose in TAE) are shown in images 6-8 of the gallery.
A new set of PCR reactions with concentrated DNA was run on 11dec, and some of the reactions was cut with HaeIII. Images from this expt are shown as 9-10 in gallery, and RA even cut off one side of the gel to see if other bands from the pcr reaction might be visible if closer to the LED light source.
It is clear that this DIY transilluminator is not as sensitive as the UNIL 'SafeImager' from Promega - image 12...
After using the UNIL box, it was clear that the non-taster band, which does not cut with HaeIII (predicted size 221bp), is visible from Sam's DNA, but still virtually no product is visible from Rachel's... (tasters are expected to have the band cut for 177 + 44bp - perhaps there is a difference in the HaeIII cut lane of RA, vs the uncut, with something smaller perhaps just there??)
The PCR test should be done again with more input DNA from RA, but also the midi size trans-illuminator should be built.