Tuesday, April 24, 2012

Small lab techniques (or nerdy, depending on how you look at it)

Last week I needed to run a gel for approximately 19 lanes, but our small gel boxes only fit up to 14 lanes. Our large gel box fits plenty of lanes, but I only needed half of the length it provided and I didn't want to waste any agarose. I came up with a solution: the usage of lab tape to cut the length of the functioning casting tray into half. Check it out:
The frugal gel--using lab tape to prevent to use of excess agarose.
The plates have dense diatom populations at the initial streaking point.
In other creative news, I'm using lab tape to slow the growth of my diatom plates. Why might I be doing this? Well, I'm growing these diatom cultures on plates to select for single clones for use in my experiments. But as you can see in the plate to the right, I have really dense diatom streaks from the initial plating. You could just yell at me to plate fewer cells, but because of the slow growth rate of diatoms (in comparison to bacteria), I usually plate a lot more cells to ensure the diatoms inoculate the plates. Additionally, the growth of my diatoms appears to be sensitive to the initial density. That is, there appears to be a starting threshold density required for successful culture growth. Therefore I plate more cells that normal in order to ensure good culture growth.

Tape on the lid blocks light above the densely populated agar.
Working form these dense cultures, I streaked out a small portion of the dense cells in order to get some single colonies. In the meantime however, I don't want the dense portion of the plate to overgrow, use up all of the nutrients, and bleach while the single colonies proliferate. So, by using tape on the top of the petri dish, I can slow down the growth of the dense population while allowing full light exposure to the single colonies. (Continued below)

Color coding of discrete diatom genetic lines!
(Red refers to my diatoms transformed with my NR-EGFP-NR DNA contructs; orange, NR-EGFP-Actin; green, NiR-EGFP-Actin)

These plates are exposed to lights at 3 points.
Here we can see that my plates are exposed to 3 different light sources. Source #1 provides a majority of the light as it is perpendicular to the plate surface. Sources #2 & #3 run parallel to the plate surface, with most of the light passing over the top of the plate (and not the sides). The way I see it, by taping the tops of the plates, I'm preventing a majority of the light from hitting the densely populated plate regions. This densely populated plate region is still getting some light however, and they should persist on the plates just fine. This was inspired by a really cool discovery for my thesis work, but I won't spoil that surprise right now. 

A single layer of porch screen is added to the taped plates.

No comments:

Post a Comment