27 November, 2003

Setting Up Our Lab and Preparing to Process

Now that we’ve returned from our first trip to the Dry Valleys, it is time to start processing the samples we collected.

Before we can start working with our samples, we needed to gather science equipment, organize our lab, and prepare the media upon which the yeast and bacteria will grow. Helping us accomplish this task are the final members of the team, Scott Craig and Barb Schulz. Scott and Barb left exactly a week after us and arrived while we were in the Dry Valleys. It is nice to finally have the entire “Yeasty Boyz” team together.

Rusty and I started our day with a trip to the Crary Lab stock room to gather the needed materials and lab equipment. An hour or two later we returned with several carts containing balances, centrifuges, pH meters, conductivity meters, shaker baths, tube rockers, incubator baths, and many other needed supplies and misc. equipment. While we were gathering equipment, Barb, Regina, and Laurie set up the lab by unpacking boxes, putting away materials, sterilizing work areas, and organizing the lab. Since microbes are found all over (on countertops, on us, etc.) we have to be concerned about possible contamination. One way to ensure that the “critters” that grow on our plates are indeed organisms we collected from Antarctic soils is to sterilize our instruments with an autoclave. An autoclave acts somewhat like a pressure cooker in that the items are heated under extreme pressure and temperature. After 20-30 min in the autoclave, any critters that might have been on the item would have been killed, thus making it sterile. Since a lot of our equipment needed to be sterilized, Barb and I spent much of the day autoclaving bottles of water and misc. instruments and items that will come in contact with our samples.

Since we are studying living organisms, we must provide a proper food source and climate in order for them to grow. Bacteria and yeast are grown in plastic Petri dishes, or plates, that contain a gelatin type food source, known as agar and then incubated at a temperature that is conducive for growth. Since we are looking at both bacteria and yeast in Antarctic soils, we must use plates that contain different types of “food”. Bacteria will be grown on Luria-Bertani (LB) agar and the yeast will grow on Yeast Peptone Dextrose (YPD) agar. We also add 2 antibiotics (chloramphenicol and ampicillin) to the YPD agar. Why would we want to put antibiotics only on our yeast plates? (Hint: What do antibiotics target?)

Now that our lab is organized, and the media has been prepared and poured, we will be ready to plate our samples tomorrow.

1. A photo of our lab taken before we left for the Dry Valleys

2. The Crary Lab Stock Room

3. Here I am pushing one of the carts containing our gathered lab equipment

4. Items that have not yet been autoclaved.

5. These items were not taken off the grill, but rather out of the autoclave. Obviously this is not your normal masking tape. Why would we want to use a tape that changes when it reaches a certain temperature?

6. Our lab a little more organized

7. Liquid media in a shaker bath. Why would we want to shake it before pouring it? Is the media sterile? How do you know?

8. Here is the color-coded system that will be used on our plates to indicate the type of media. What do the thick lines mean? And the thin lines? (Hint: Look at the key) We will have two different types of plates. What will our plates look like?

9. Me, Dr. Connell, and Dr. Redman color-coding the plates

10. Dr. Rusty Rodriguez pouring the liquid media into the plates. The media will sit over night to cool and solidify.

11. Can you tell which plate is which? Why is the agar on the two sets of plates different colors?