What if some of your common practices in the lab were actually having a significant effect on your results...and you just didn’t know about it? Recently, a group of researchers from Utica College found that the practice of using parafilm to seal agar petri dishes containing the model organism, Caenorhabditis elegans, actually has a significant effect on its early development.
C. elegans is a nematode and a well-established model organism which is often used to model various aspects of development. This organism is often grown on Nematode Growth Media (NGM) agar in a petri dish.
NGM can sometimes dry out or become contaminated by microbes, so to prevent this, researchers often wrap up the petri dish with parafilm, the way you wrap up food containers with plastic wrap in the kitchen. This practice has been used for a long time, however, it has never been fully explored to see if it actually affects nematode development. In this study, researchers tackled this very question and investigated whether wrapping NGM agar plates with parafilm had an effect on larval growth and development.
In their study, the researchers found that both the larval growth rate and length change after 48 hours were significantly increased when the NGM agar plates were wrapped with parafilm.
Researchers also found reduced variability in growth among parafilm-wrapped replicates in this study. This echoes findings of a which looked at the effects of parafilm on the model plant, Arabidopsis thaliana. Overall, this suggests that parafilm helps to create a standardized condition for measuring responses in model organisms.
Any researcher that uses parafilm as common practice with their organism should be aware of these possible effects and take the time to identify if this practice of wrapping up has any influence on their results. And in addition, perhaps there are other types of common practices out there that can affect results...that we just don’t know about yet.