Where did you obtain your soil sample?

I obtained my soil sample from outside the new S&E building next to the construction site.  Professor Salvo suggested this location, because she felt there would be interesting organisms there since the soil had not been turned over in many years.

Why did you choose this location?

Having stagnant soil allows for the growth of many different bacteria without disturbing any of them.  I chose this soil sample, because Professor Salvo and I knew there would be interesting organisms present that had not been disturbed in many years.

Did you expect a lot of isolates? Why or why not?

I expected some isolates, but I didn’t expect too many – the soil was sandy in texture and I thought that the organisms present would have a difficult time finding nutrients.  I did, however, think that this would make them more likely to produce antibiotics to fight for these nutrients.

Have your initial observations supported this?

My initial observations were that the bacteria grew out of control on my less dilute plates, but they grew beautifully on the more dilute plates.  I have also noticed a substantial amount of what appears to be AB production, but I will only know if this is the case after further analysis!  My observations that the less rich media (R2A) grew fewer bacteria was supported by the decrease in growth at the same dilution levels as the LB and AC plates.

What media did you choose?  How did your sample differ on the different media?

I chose the R2A (less rich), LB (rich), and AC (rich) medias.  I did this to support both bacteria that thrive in low nutrient environments as well as those that thrive in nutrient-rich environments.  I noticed that the bacteria grew at about the same rate in the R2A as the AC and LB when it was at a dilution 10 times less than the rich counterpart.  For example, when R2A was at 10^-1 and LB and AC were 10^-2 it seemed that they were closely related in growth.

What dilutions?

I ran my R2A at 10^0, 10^-1, and 10^-2 while I ran the LB and AC at dilutions of 10^-1, 10^-2, and 10^-3 dilution factors.

Will you need to redo any?

The dilutions worked beautifully.  The best example I can give of how well the dilutions worked was from the LB plates.   The 10^-1 plate had too many colonies to count, but the 10^-2 plate had 90 and the 10^-3 plate had 9 colonies.  This showed that the dilutions were accurate, and the plates were growing as expected.