S-STEM Scholar Evan Russell's Blog

Introduction          We have observed that the resazurin compound appears to be cleared by enzymatic activity created by the inoculates. Alternatively, it is possible that the resazurin is turning from blue to pink to clear before we are able to observe the color shift or perhaps the concentration of resazurin is simply to low to be able to adequately see the pink color.           We have also observed that the cells do not seem to twitch to the same extent as they did last semester. This may be caused by a lower concentration of cells initially inoculated.          Malic also appears to act as a repellant as cells grow around the malic pellet. It also is possible that malic simply kills the cells and inhibits growth rather than acting as a true repellent. We also want to look into whether or not the density of the pellet itself is also acting to inhibit growth.          Oddly, almo...

  Introduction          This week we received our first look at the twitch plates mixed with resazurin to try to better visualize results. We looked at building better concentration gradients for the chemoattractants as well. Overall, we decided to investigate multiple new avenues to better track twitch using different dyes, plate sizes and chemoattractant gradients.  Methods Twitch Motility Assay Protocol 1) Select media (e.g. 0.75% SMA and 0.5% agar) 2) Prepare a sterile hood by wiping everything down with ethanol 3) Melt media down 4) Wipe down all inoculating materials and insert them into the sterile hood 5) Dispense 10 ml of media into empty petri dishes containing five pronged molds to allow for insertion sites a. Use a sterile 10 ml pipette 6) Let plates cool 7) Remove molds 8) Use UV light for 15 minutes to ensure sterilization of plates  9) Inoculate center of plate (directly onto the plastic) 10) Dispense 100-150 m...

Introduction This week we are going to use SMA plates mixed with Resazurin to show the spread of our twitching bacteria in a way that is both visually pleasing and easy to spot. The resazurin mixed with SMA will create blue or violet plates that should turn pink in areas where bacteria are present because the process of reducing NAD+ reacts with the resazurin and changes the color. Thus, even when we cant see the twitching cells anywhere besides the inoculation site, we will still be able to see where they are by the color shift. Methods Twitch Motility Assay Protocol 1) Select media (e.g. 0.75% SMA and 0.5% agar) 2) Prepare a sterile hood by wiping everything down with ethanol 3) Melt media down 4) Wipe down all inoculating materials and insert them into the sterile hood 5) Dispense 10 ml of media into empty petri dishes containing five pronged molds to allow for insertion sites a. Use a sterile 10 ml pipette 6) Let plates cool 7) Remove molds 8) Use UV light for 1...

Introduction     This week we are going to introduce attractants to cells sooner in order to get a better directed motion. This should help the inoculates encounter the attractants at a much earlier stage. P81 will be inoculated as the experimental condition with D. radiodurans (a non twitcher) used for comparison.      Additionally, we will have to repour the resazurin plates. Autoclaving them caused them to oxidize more than we would have hoped. According to literature, if we keep the media below 50C it should remain unoxidized (which can be visually confirmed by a blue color). Methods Twitch Motility Assay Protocol 1) Select media (e.g. 0.75% SMA and 1% agar) 2) Prepare a sterile hood by wiping everything down with ethanol 3) Melt media down 4) Wipe down all inoculating materials and insert them into the sterile hood 5) Dispense 10 ml of media into empty petri dishes containing five pronged molds to allow for insertion sites a. Use a sterile 10 ml...