TUDelft/22 September 2008

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Contents

September 22nd 2008

3A Assembly

We've received our last thermopart from GeneArt and have started construction of the two remaining parts today. The parts under construction are now K115030 and K115035.

Growing induced cultures

We've started low temperature (26ºC) growing of induced strains today. Cultures grown contained either pSB1AT3 + P1010, K115012, K115029, K115031, K115032 or K115034. Some had different plasmids, either pSB1AT3 or pSB1AK3, so we've grown them on Ampicillin to reduce growing conditions variation. We aimed for lysis on Wednesday (OD=0.6). However that was planned for T=20ºC, and the temperature of our water bath could not go below 26ºC. We'll lyse the cells when they are ready.

Protein determination

To find better values to correct luciferase measurements for (instead of OD), we've measured total protein content. To make results easier to view we've made the following calculation: Correct luminescence for protein content by dividing each measured luminescence by the protein content of the sample. Normalize the luminescence of the thermosensitive construct K115034 for the luminescence of the control construct K115012. Results displayed in table 1 are the final outcomes for these normalized values per sample treatment. Please note that these first measurements are more important for optimalization of our protocols, not for reliable results of our constructs.


Table 1: Normalized luciferase expression of construct K115034 under various growing/lysing conditions
Growth schemeLysis methodProtein content (ug/ml)Normalized luciferase expression
Induced: 20 h @ Tr Sonification 0.87 1.76
Induced: 20 h @ 37oC Sonification 1.88 0.35
Non induced: 15 h @ 37oC; induced: 5 h @ Tr Sonification 2.37 316.65
Induced: 40 hours @ Tr Sonification 2.47 0.09
Induced: 40 hours @ Tr Promega Lysis buffer 2.37 0.24

Much conclusions still can't be drawn on these data. There was an indication the R0080 arabinose induction might not be working properly. Either we'll have to use F2620 as promoter or just keep growth at the temperature desired. Another option might be to use the commercial pBAD vector.