YPS
- 5g yeast extract
- 10g peptone
- 10g sucrose or sugar
- 500ml distilled water
- First step measure everything, then put all the ingredients in a glass bottle, shake it until no lumps of dry ingredients are noticeable. Remove the bottle cap wrap it in foil, top the bottle with a piece of foil, add the autoclave tape as it is a process indicator for steam sterilizers. Put the bottle and bottle cap in the autoclave (machine that applies high-temperature steam to sterilize objects).
Though autoclave tape may have changed color during the sterilization process, this does not necessarily mean that an item is fully sterile. The tape will change upon exposure to the desired temperature it is indicated for. However, for proper steam sterilization to occur, the entire item needs to reach and maintain a temperature of 121 degrees Celsius for 15 to 20 minutes to ensure the items' sterility.
Note that autoclave tape and the indicators do not prove that the sterilization process has killed organisms. Instead, they demonstrate that the autoclave has reached a temperature of 121 degrees Celsius. Environmental, Health and Safety recommends that you do not use autoclave tape as the only indicator of decontamination or sterilization.
When using autoclave tape, attach it to the exterior of the item you want to sterilize. Depending on the kind of autoclave tape you use, the tape will change to a specific color.
Yeasts are eukaryotic microorganisms whose genomes have been comprehensively studied and some have been sequenced. They are relatively easy to grow under laboratory conditions. Moreover, despite their small genome size, they display cellular features and processes that are highly conserved amongst most eukaryotes. For instance, they have membrane-bound organelles, cytoskeleton, nuclear DNA, and transcription mechanisms that are similar to those found in higher eukaryotes. Furthermore, yeasts have many well-characterized secretory proteins and pheromones. Several yeast genes involved in protease processing and secretion have also been identified. Thus, yeasts can be used for several eukaryotic gene and protein studies with the aid of suitable molecular biology tools. Some applications for yeast cultures include synthesis of protein expression systems, the study of specific gene or protein functions, and the analyses of novel protein interactions.
YEAST MEDIA OPTIONS
1. YPD medium
A nutritious medium available in liquid (broth) or solid (agar) forms for the growth and propagation of yeast cultures. It primarily contains of bacteriological peptone, yeast extract, and glucose. This medium is non-selective for Candida, Pichia, Saccharomyces, and Zygosaccharomyces.
2. Yeast Synthetic Drop-out Medium Supplements
The selection of plasmids in yeast is usually based on the use of auxotrophic mutant strains, which cannot grow without a specific medium component (like an amino acid, purine, or pyrimidine). Transformation with a plasmid containing the mutated gene enables the transformant to grow on a medium lacking the required component. Thus, drop-out medium supplements can be used to select transformed yeast cultures.
Please refer to the selection guide below for further details.
3. Yeast Nitrogen Base (YNB with or without amino acids)
Yeast Nitrogen Base is a highly-referenced growth medium used for the cultivation of yeast. This nutrient-rich microbial medium contains nitrogen, vitamins, trace elements, and salts. It is suitable for use in classifying yeasts based on amino acid and carbon requirements. With an added carbon source, YNB with amino acids can be used for susceptibility testing of fungi.
