About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.
Hello, everyone. I need help! I am currently taking Microbiology, and have the Unknown microbe project. I have identified my microbe as E.coli. My problem is that I forgot to get all of my information from my streak plate to describe my colony. All that I wrote down was that I thought it was circular, with an entire edge, smooth, and raised. Also I have that it looked translucent and white. I wasn't too confident that I described it properly, and have been trying to find a description for E.coli so that I could compare it to what I wrote down. Does anyone have this information, or a link to a website where I can find it? I have searched and can not find anything. My professor wants us to list the pigmentation, opacity, form, margin, surface, and elevation. I would greatly appreciate the help!
No, I am not trying to make up data. I already have the conclusion. I simply want to find out if my description of my colony matches what it should be. I no longer have my streak plate, and I am curious to see if my description is correct. If it is not, at this point there is nothing I can do about it - I just want to know if what I saw is correct. My professor has already advised me that I am correct in my findings, that it is E.coli. Our lab manual just does not have a description of the colonies, and I am not 100% sure of how to tell if what I thought the colony was is correct. In our lab we only did descriptions of the colonies once, and I am just not sure if I looked at this one properly. Regardless, E.coli is not a microbe that you could identify by a Streak Plate only, so why would you think making up data for a streak plate would match my conclusion? I simply want to know if what I noticed was correct or not - I am not trying to "make up" any data.
Maybe I should re-phrase this. So as not to be accused of "making up data" - rather than giving me a link to any information, I have already provided my findings in my first post, which were:
Can someone simply advise me if my description is correct for E.coli? I just want to know if I was able to properly describe my colony. I already have positive tests in other areas that have 100% determined my microbe as E.coli. I know my other tests are correct - I simply want to know if I described my colony correctly. I have only had to describe one other colony in my lab, and quite honestly – while this should be an easy thing to do, I seem to lack confidence in this area. For me, the hardest part is telling elevation while looking at the Petri dish. Color, opacity, and margin I get. I’m not sure I understand how to tell surface or not. Elevation is hard for me to see, and form is sometimes hard for me to tell as well, although that I believe I can figure out. This is my first micro class, and the first time I’ve had to do these things. I was simply wondering if I was correct. If no one wants to advise me of that, then I will certainly just wait to see what my professor says, and that is fine. Thanks, anyway.
You are correct some strains of E. coli are smooth, circular and raised. (Some E.coli is iregular and rough). White and opaque also sound right but I can't be 100% positive.
Do you retain your isolate on a slant or in the freezer? An new plate would grow colonies in 24 hours. Then you could be certian.
BDeis - thanks so much for your reply. I do still have my unknown sample - so I could go and do another streak plate on Monday, just to be certain. Our professor keeps our unknowns in tubes in the refridgerator (as a broth). I believe I could get enough growth on the plate by Tuesday, if I place it in an incubator instead of doing it at room temperature only. I believe that I saw it correctly - but I was just a little uncertain. I truly appreciate your response. I also hadn't thought about the fact that it would only take me 24 hours to do another streak plate - so I will try that as well. THANKS!!!
Just did this in lab with my prof. My specimen of E.coli had: circular form, filamentous margin (I had a hard time seeing this), raised elevation. We used an antiquated-looking piece of equipment called a "disecting microscope" that magnifies to 200x. So as far as the color? It's unpigmented ("white") and perhaps b/c of this scope that really, the light source was basically an unattached lamp that you had to tilt to get better lighting... to me the E.coli looked a little darker than transluscent. I could not see through the center, but I could kind of through the edge.
can someone tell me the meaning of "existence" in identifying microbes? and what existence does E. coli?
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