Today in class our goal is to determine how successful our culturing effort has been so far
1. Pull out your culture plates.
2. Count and record the # of colonies per plate. Use a marker to dot each colony as you count it to keep track.
3. Identify colony types (bacteria, fungi, yeast) using a microscope
4. Each person will perform a PCR of ~8 colonies
5. Select a few of your colonies for pure culture isolation – move isolates to new plates – you can do this for ~4 colonies
***KEEP CAREFUL TRACK of source sample, initial plate ID, & new plate ID in your notes***
Hints (this is Emily’s summary of Rytas’s geshtalt)
If you are looking at circular colonies:
Bacteria: Each distinct circular colony should represent an individual bacterial cell or group that has divided repeatedly. Being kept in one place, the resulting cells have accumulated to form a visible patch. Most bacterial colonies appear white, cream, or yellow in color, and fairly circular in shape.
Yeasts: Yeast colonies generally look similar to bacterial colonies. Some species, such as Candida, can grow as white patches with a glossy surface.
bacteria vs. yeast – bacterial cells are smaller — you can’t see the individual cells of a bacterial colony at 100X – you can see them if they are yeast colonies
Molds: Molds are actually fungi, and they often appear whitish grey, with fuzzy edges. They usually turn into a different color, from the center outwards.
If you are looking at filamentous colonies
Bacteria: things like Bacillus grown in dendritic patterns but you won’t be able to see distinguishable cells
Filamentous fungi – filamentous hyphae
**for some this may be hard unless you actually look at them under higher magnification**
****PRIZES FOR THE DAY*****
Most colonies
Most colors
Biggest single colony
