¶ 30 July 2021
Well, “tomorrow” became a 5 day wait. Status of the cultures in the 4°C fridge:
I'd like to make an LB agar control plate for this round of streaking. Using the lab microwave I boiled a bottle of LB agar from lab stock, then kept it warm on a hot plate set at a plate temperature of 85°C, which appears to keep the bottle contents around 50°C. I let the bottle temperature stabilize over two hours while having supper.
This worked! When I came back and poured my first plate, the agar was still fully liquid. No semisolid or solid chunks poured out like last time. Following Wendy's plate-pouring protocol (7/30/2021 snapshot), I poured my “LB only” control plate first. Then I added 250 µL of 1000x chloramphenicol stock solution to the agar and swirled to mix before pouring the other plates, which will be labeled “LB+chloro”. I let my plates dry with their lids slightly open under the laminar airflow for 45 minutes:
After 45 minutes, the plates were solid and most of the lids no longer showed any condensation, implying that the plates have dried enough. I proceeded to streak them, one plate per tube, following Wendy's plate streaking protocol (7/30/2021 snapshot). As mentioned before, I have two control plates, LB only and LB+chloro. Using a lab marker (VWR black) I divided each plate in half. Here's what I expect to happen in each half if the antibiotic is effective and my technique was sterile:
| blank | DH5α | |
| LB only | no growth | colonies/"lawn" |
| LB+chloro | no growth | no growth |
