Lab2 background and protocol

Background

In this laboratory, you will learn and use a number of different terms.

Inoculate is to purposely grow an organism by putting it in some media, and to contaminate is to accidentally grow an unwanted organism.

Media contains all of the nutrients to grow an organism but there are no actual organisms in the media until you put them there.

There are two types of media that we will use – media that comes in a tube (broth, slants and deeps) and media that is put into a petri dish.

(Look at the power points to see pictures of the different types of media)
 

After we inoculate our organisms into media, we will then incubate the tubes or plates.

This means that we will let the organisms sit or sometimes shake at a certain temperature to allow them time to grow. We usually shake the tubes in an incubator and the plates will be placed in a different incubator that does not shake.

All of the media and tools that we will use in this laboratory are sterilized before we use them so that they are free of any organisms.

Throughout these procedures, you will use the aseptic technique so that you do not introduce any unwanted organisms into your cultures.

            Please look at the power points for this week to review the aseptic technique.

Another word that you should be familiar with is asepsis which is the absence of contamination.

Protocol

First lab period

Part A

Select a partner.

One of you will work with the organism Staphylcoccus aureus (SA) and the other person will work with the organism Proteus vulgaris (PV).

1 person of your group with inoculate  Staphylcoccus aureus  into a deep with a needle.

1 person of your group with inoculate  Staphylcoccus aureus  into a slant with a loop.

1 person of your group with inoculate  Staphylcoccus aureus  into a broth with a loop or a needle (I prefer a loop).

1 person of your group with inoculate  Proteus vulgaris into a deep with a needle.

1 person of your group with inoculate  Proteus vulgaris into a slant with a loop.

1 person of your group with inoculate  Proteus vulgaris into a broth with a loop or a needle (I prefer a loop).

Your group of 2 should have a total of 6 tubes:  2 deeps, 2 slants and 2 broths.

Part B

Everyone will work individually on this part.

Take 2 agar plates.

Streak one with the mixed culture (this may be labeled MX).

Streak the other culture with one of the liquid cultures that you previously made.

You will be streaking for isolation.

Second and third lab periods

In these two lab periods,  you will observe your tubes and plates and streak again.  You can try using an isolated colony if you have any.

When you are observing your tubes and cultures, there are various terms that can be used to describe them.

The picture below shows some terms that are frequently used to describe the growth in slants:

The picture below shows some terms that are frequently used to describe the growth in broths:

The picture below shows the motility in a deep:

The tube on the left is very motile, the tube on the right is slightly motile and the tube in the middle is non motile.

 
In order to describe the colonies on your plates, you will need to observe them under a dissecting microscope.

I have shown below, two figures that give terms to describe these colonies:

Please complete the following tables with the observations from your tubes and plates and put it in your notebook: