Would you prefer smoking, non-smoking, or oxygen free? Lab Day 4

Monday, day 4

Today we started out lab by inoculating a thioglycolate tube with our unknown bacteria.  At the top of the tube we can see that the color is red, and as you look towards the bottom of the tube, the color changes to yellow.  The red color signifies an oxygen rich environment.  The yellow part of the tube signifies an oxygen poor environment.  We did this test to see where our bacteria would grow.  If it grows in both environments, then our bacteria is facilitative, but if it only grows on the top or on the bottom then it is an obligate aerobe or obligate anaerobe.

Our next test was completed to determine if our bacteria was motile or not.  This was comprised of simply inoculating a gelatinous tube with our bacteria.  We used our pointed rod and stuck it down to the bottom of the tube.  Tomorrow we will determine if our bacteria is motile or not.  If it is motile, then the bacteria will move side-to-side and form a cloudy region around it, but if it is not motile, then not much will happen.  

The next test we performed was done to determine if our sample was an anaerobe or aerobe.  We did this by first taking a clear bin and putting all of our bacteria in it.  Next, we added a blue colored test strip that helped us indicate if oxygen was present or not.  If the strip was blue, it meant that oxygen was present.  If the strip was white, this meant that the strip was in an oxygen poor environment.  This is important because we were testing to see if our bacteria will grow in oxygen poor environments, so knowing if oxygen is present is of great importance.   After we added the strip and bacteria, we placed in the container three bags that looked and felt like hand warmers.  These bags deplete all of the oxygen in the container.  

In the last part of the lab we started by inoculating a petri dish with our unknown bacteria.  Then we added a virus to the bacteria.  In theory, when we apply the virus to our bacteria, the viral bacteriophages will inject their DNA into the bacterial cell, multiply inside the cell, and cause the lytic cycle.  This should destroy some of our bacteria, at least in the area where we applied the virus.  We’ll see tomorrow how much damage is done.