When we need to use a specific strain of yeast for a protocol, we first must grow it up overnight. Whether the strain is frozen in the -80°C Freezer or fresh on a yeast media plate, the process of overnighting is the same.
As with any procedure involving living organisms, sterile technique is a must. Please ensure you are following the proper sterile technique protocols.
Put a 1" sticker on top of each culture tube lid with the appropriate yeast genotype name. Label a piece of lab tape with the appropriate information (MM#, date, initials, Mating type, and any extra info about the strain). Put the lab tape on the tube.
If getting the yeast strain from the -80°C Freezer, wear both nitrile gloves and polar bear gloves. Take strains to be overnighted from -80°C Freezer referencing the -80C freezer map for the box location of the strain. Pull one box at a time; keep freezer closed as much as possible to prevent thawing. Do not touch cold tubes with ungloved hands. Use a sterile pipet tip to scrape a small amount of yeast from the tube.
If overnighting from a fresh colony, if you ever see more than one obvious colony size (this should be rare), stop and talk to someone about how to be sure you are using the correct colony / genotype, before proceeding. Use a sterile pipet tip to take a small amount of the colony. NEVER take all of the colony. Circle the colony on the plate and write your initials and date.
Flame off the lip of the appropriate culture tube containing LIQUID YPD. Tilt the culture tube toward you (over bench, not your lap), allow LIQUID YPD to flow toward lip. Dissolve yeast from pipette tip into YPD. Flame off the lip again and replace lid.
Place tubes into 30°C Shaking Incubator at an angle, and press the shake button. Allow to shake overnight.