When some experiments are a mess

Sometimes in Science the data you expect from your experiments do not appear. This is the reason why Biology, or Microbiology in this case, is an experimental Science. As you already know last experiments should have indicated a putative mutation frequency affected by the uv treatment. However, we have only data from the plates incubated at Paula’s Home (Fig. 1; 3I plates). The plates incubated in the Lab (3G plates) are a real mess!

 

Figure 1: images of the plates with identical dilutions of 3I (Paula’splates) and 3G (Labplates)isolates. Above plates indicating total bacteria (TY plates). Below plates indicating mutants in SacB gene (Sacarose plates). In 3G plates the bacterial spread was not properly done. Plates were not dried before to perform incubations.It is difficult to count colonies and to be sure of the dilutions performed.

Which is this difference of this result with the previous one (see last entries)?

 As I mention, something (just a Little detail) was wrong. I found out that the plate were humid when I saw one day later after incubation. This humidity is critical to form single colonies (also occur in previous experiments). Does it!!!.

However, in spite we can not yet estimate the mutant frequency. We can deduce that the experiments are, in principle,well performed. Uv treatments looks to have in effect on bacteria, and the dilutions calculated are probably right in order to get the accurate conclussions of our work.

Come onstudents!!

We have to planify the next experiments in order to avoid this error. Plates must be dry by standing opened for a while (3-5 min) before to close with parafilm and put in the incubators.

Again, next session is awaiting us!!

That is Science!! Be patients and consistents.

Francisco Martínez-Abarca

Estación Experimental del Zaidín. CSIC.

Granada