On Belkin et al (1996) and later studies, kanamycin was omitted due to inhibit protein synthesis as it's mechanism of action but on van Dyk et al (1994) kanamycin was included in luminescence reading.
When ampicillin used instead of kanamycin, no luminescence inhibiton was observed. E. coli bioluminescence contain pUCD615 with luxCDABE, recA/grpE/fabA/katG promoter and kanamycin and ampicillin resistance.
At least in Belkin work, the luciferase is produced after exposure to the condition (peroxide etc). I guess they want to avoid possibility that kanamycin will inhibit production of luciferase. You will never know how the uptake of kanamycin or the resistance mechanism activity will be changed after treatment with peroxide etc.
It might not be necessary so that even in the presence of kanamycin the sensoring will work more or less.
Kanamycin is a potent antibiotic. Even when bacteria are resistant to it they can show significant growth inhibition due to its impacts.
To see this for yourself, grow colonies of this strain or any kanamycin E. coli strain that is stable (such as the KEIO strains) on kanamycin plates and blank agar plates. The kanamycin colonies will be much smaller after growth overnight. This growth "inhibition" can influence the test results as the bioluminescent output is influenced by the cell growth.
BTW, I am a good friend of Belkin and know van Dyk, and even work with those strains in my lab as well. ^^ (Look at my publications for proof if you desire)
When we do these experiments, I also advise my students to grow the bacteria on KAN/AMP plates to prevent any possible contamination but once we inoculate LB media, only ampicillin is used.
Hope that this helps.
Thanks very much Hannes and Robert.
For Robert, I have read your journal too.
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