WEEK 3: Cross Contamination & Gram Staining

On February 13, I went ahead and began another isolation plate for E. coli due to the amount of time that had passed by. As you can see in the images below, the original cocci or circular shape of E. coli cells had denatured into coccobacilli mostly because of how old the bacteria had gotten. In addition to the E. coli isolation plate, I began one for Bacillus subtilis.  Both isolation plates were placed in an incubator to stay overnight and be checked for growth the next day.

The next day on February 14th, as I observed the growth on the TSA Isolation plates for E. coli and B. subtilis, I discovered that the B. subtilis plate had been contaminated with a different type of microbe. With further observation, we came to the conclusion that the broth culture of B. subtilis had been contaminated considering how much precautions I had taken to inoculate the first isolation plate. Therefore, the culture that I used to inoculate was disposed of, and a new culture was used to inoculate a new TSA plate to isolate some colonies of B. subtilis. 
After this was taken care of, I proceeded to move on to observing the E. coli plate, and after seeing that it was good, I went ahead and did a Gram stain. this time the cell shape was circular and violet.