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Media. We will be working with 4 types of media in this lab. One type is put in a petri dish The other three types are in tubes A broth media is all liquid and is inoculated with a needle or a loop A slant culture is completely solid and is inoculated with a loop
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We will be working with 4 types of media in this lab • One type is put in a petri dish • The other three types are in tubes • A broth media is all liquid and is inoculated with a needle or a loop • A slant culture is completely solid and is inoculated with a loop • A deep media is partially solid and is inoculated with a needle • A slant and a deep differ in the amount of agar that they have
This is a needle Shown below is a picture of a loop and a needle This is a loop
Notice that there are colonies that grow on top of the agar This is the media in a petri dish
The growth is observed under a dissecting microscope The terms to the left are used to describe the colonies Growth on plates can be described as colony morphology
The slant is on the left The broth is in the middle The deep is on the right These media are grown in a tube
This is what a broth culture looks like when there is growth; notice there are no colonies present
How can you tell if your culture is pure? • View their colonial morphology by streaking the culture on a plate • View their cellular morphology by preparing a smear (staining it) and viewing them at 1000X magnification
What would you see if your culture was not pure? • Streak plate would have colonies with different colonial morphologies • Cells under the microscope would have different cellular morphologies and staining properties • Gram + and gram – • Rods and cocci
How can you culture become contaminated? • Leaving it open too long • Accidentally touching or setting down your loop or needle • Working in an environment that contains a lot of airborne contaminants • Forgetting to flame your loop or needle properly • Resting your broth on its side so that some of the fluid goes up into the cap and down the side of the tube
The tube on the left is very motile The tube in the middle is not motile The tube on the right is motile Hold up the tubes and look for growth and cloudiness around the needle inoculation point to determine motility The deep media is used to measure motility