Like a lot of C. elegans researchers who stroll the booths at conferences looking for the panacea that will expedite my experiments, I have had my eyes on LabTie’s freeze dried bacteria for a couple of months now. It could be a great way to reduce the variability of food source and streamline worm maintenance without having to deal with overnight incubation.
I finally got some free freeze dried OP50 samples from the 2017 international worm meeting in June. So I decided to put this food source to the test before potentially making it part of my worms’ diet.
If this food source turns out to be of good quality, it would definitely be a game changer in our lab. We have limited space and are still waiting for a centrifuge that we would use to prepare liquid food source when we quantify feeding behavior in our microfluidics chip.
We’re going to start small, but we have a couple of questions that I’d like to tackle:
- Do worms eat this freeze dried OP50 recipe?
- Does their feeding behavior differ on fresh OP50 compared to freeze dried OP50?
- Does it affect the worms’ developmental and aging process?
We usually grow our worms on a bacterial lawn and resuspend a pellet of fresh (less than 1-week old) OP50 to feed them in the ScreenChip while we record their behavior.
The table below shows the difference between the bacterial preparation of the freeze dried bacteria, versus our current protocol (fresh OP50 inoculate).
Table 1: Final concentrations of freeze dried and fresh OP50
|Type of Culture||Weight (mg)||Buffer||Volume (mL)||Final Cont (mg/mL)|
|Freeze dried OP50||bacterial lawn liquid culture
|Fresh OP50 inoculate||liquid food source||100 (not 100% dry)||M9||1||~50|
I want to test our current protocol in parallel with the LabTie formula, following their protocol (see table 1), so we are going to look at a couple of experimental conditions.
Here is our experimental design for now:
Figure 1: Experimental plan (FDB: Freeze dried bacteria, D1-5: Day 1-5 adults)
Left: We’ll start by testing the feeding behavior of Day 1 adult C. elegans who have been cultured on a classic lawn of fresh OP50 (acute exposure).
Right: We’ll then look into how C. elegans grows on a freeze dried bacteria lawn. We are planning on testing feeding and morphology over time.
Other users have reported contamination issues, so we’ll keep a couple of unseeded plates over time to control for contamination as well. I’ll post the data as we go along, as well as some pictures.
To be continued…