With week 14 we continue research after the earlier contamination setback. As can be confirmed from photos 1-3, the colonies re-grown after the contaminated colonies were disposed of are pure E.Coli. We have obtained and are now working with a new E.Coli strain as well: E.Coli strain B, with hopes that the new strain will be a more prolific host for the phages and produce better results faster and more effectively. A bubbler setup was created (Photos 4, 5) to grow the phages, again, in hopes that the process will be more productive and give stronger results and phage output. The last step of the process to purify phages was to run the phage/E.Coli broth through a sterile filter mechanism to filter out E.Coli cells and cell parts and get a pure phage stock (Photo 6).
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Week 13 is a continuation of growth of E.Coli and testing for killing using the phages. A small setback occurred during this round of testing that involved a contamination problem. It was found that the E.Coli stock we had been working with had gotten contaminated somewhere along the way and the reason we weren't seeing as much killing of our culture was because it was the wrong culture and the pages aren't built to kill it. After gram staining (pictures 1,2, and 5) we could see that instead of a gram-negative individual bacillus (pink, individual, rod-shaped cells) we were looking at a gram-positive strepto-bacillus (purple, chain-linked, rod-shaped cells). Unfortunately thus is the nature of microbiology and bacteriology; when working with subjects and organisms this small and numerous often contamination occurs and there is no clear source or fault. It just happens. Despite this, we will kill all contaminated sources and continue onward with experimentation. Setbacks happen, but all we can do is learn from this and press forward. |