The Results: Motility, Colony/Morphology, Strep, and More!

The results are in!

Were our bacteria samples motile?

Our Environmental Sample:
As seen below, there is only cloudiness evident on the length of the pin down this tube.  This proves the bacteria to be non-motile.  The bacteria grew throughout the length of the tube; however, it grew better in the bottom of the tube in anaerobic conditions (in the absence of oxygen).  Because of this growth pattern, we presume that our bacteria is an aerotolerant anaerobe bacteria.  This type of bacteria grows better in the absence of oxygen but can still grow if oxygen is present.

 Sample "F":

This sample, our unknown, is also non-motile because the cloudiness is only evident where the pin was inserted into the agar medium.  However, this bacteria grew better in aerobic conditions because the bacteria flared out on the surface of the agar.  We concluded that this was a facultative anaerobe  because they do not require oxygen for growth but utilize it when it is available.  Clearly, this bacteria utilized the oxygen present at the top of the agar medium because it grew much more rapidly there.

Left: Sample "F"  Right: Environmental Sample

This picture above is another record of our observations.  Looking at the bacteria in front of a light source helps reveal cloudiness.

Another way that we tested for motility was by observing LIVE bacteria!  We did this by using our broth samples that we prepared last class.

First, we swirled the broth tubes by flicking them with our fingers until cloudiness appeared.  After this, we applied Vasoline to the slip cover to later keep it stationed on the depression slide.  

We added a drop of the broth to the cover slip using a sterilized inoculating loop and aseptic technique.  The cover slip was then stuck to the depression slide with the drop hanging over the depression.  This is necessary to see bacteria moving!

 However, to no surprise, no bacteria was moving in our suspended drops of broth.  The only thing observable was the bacteria drifting through the broth, but not moving by its own means -- proving it to be non-motile.

What is the colony/morphology of our unknown?

This is "F":

To identify the colony/morphology of "F" we needed to view it under a microscope.  Here is "F" -- MAGNIFIED!

Sadly, our culture of "F" overgrew and we were unable to locate a single colony; however, above are some pictures of our results.  We started a new culture on a new agar plate for next class to fully be able to idnetify the colony and morphology of our unknown.  However, from what we could examine, "F" is a small cocci bacteria.  It has a flat and ridged appearance and is cream.  However, what is science without a hypothesis?  This misfortune gives us an opportunity to predict the colony and morphology of "F."  We predict that "F" will form entire, circular colonies that are opaque.

DID DR. JOSEPH HAVE STREP?

 Lysing did occur! But does that mean that he has strep?  Luckily for him, NO!  It is hard to see in the picture above, but the green residues reveals an incomplete lysis of the bacteria in the back of his throat.  The bacteria that causes strep throat is known as Streptococcus pyogenes.  In encountering the antibiotics that were present in the agar medium, this bacteria undergoes complete lysis; because complete lysis did not occur, the bacteria that causes strep is absent from the throat culture.

What happened with the T-4 Virus?

Dr. Joseph put the same bacteriophage in both of the agar plates above, but with different bacteria in them.  On the left, there is a patch of clear agar reading "JAP" (professor's initials) that indicates that lysing of bacteria did occur.  However, the second bacteria (on the right) was not affected by the T-4 bacteriophage.  This is because each bacteriophage has its own set of hosts!  Just as only certain viruses affect humans, certain bacteriophages affect certain bacteria!  This proves a point: every virus has a host range!

What will happen next week?  Plenty of surprises!  What will our new culture of "F" reveal?  Will our predictions be correct? Turn on your computer next week and check it out!