In my lab we\'ve observed a phenomenon in which a culture of E. coli is found to
ID: 31769 • Letter: I
Question
In my lab we've observed a phenomenon in which a culture of E. coli is found to shift from normal rod growth to filamentous growth and then back to normal rod growth again several times over the course of 400 hours. This was shown by an OD600 graph which oscillates from high values (~5) to low (~0.5) (the culture was also viewed directly).
The shift to filamentous growth is usually associated with an SOS response in E. coli and this makes sense (the media is M9 supplemented with 0.2% casamino acid and 0.1mM thiamine hydrochloride), however we don't know why it switches back from filamentous to normal growth.
Has anyone observed a similar phenomenon? Does anyone have any suggestions why this might be happening?
Explanation / Answer
Expression of sfiA (sulA) causes filamentation during the SOS response, so presumably sfiA is induced, as part of SOS, in response to some sort of DNA damage. Once the DNA damage is repaired the SOS genes, including sfiA, will be repressed again and normal growth will resume.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.