laperry
Forum Newbie
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I am working with Vibrio fischeri and I have this phenotype on motility agar that I can't explain. I have attached a picture of it. There appear to be some kind of clusters in the agar (all of it is in the agar, they are not swarming) Additionally, near this region with the clusters, they "repel" surrounding bacteria, however when given more space, they will form a secondary ring that has no clusters and will run right into a neighboring ring. Does anyone know what could be causing this, have any suggestions, or just seen something like this before?? (i do have more pictures too)
Attached Files:
H901521.jpg (78 KB, 10 downloads)
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| bactitech
Forum Elite
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I have never seen motility agar in plate form. I've only ever used semi-solid agar in tube form (SIM). Did you inoculate the organisms in the grid pattern? They must be moving out from the central inoculum. That is really weird. Why are you using a motility agar? Are all these circles the same organism?
Why are you working with this particular Vibrio? I'm pretty unfamiliar with this genus, as we have to set up special plates (TCBS) agar if a doc wants it checked for on stool cultures. I've never heard of this particular species.
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Clinical Microbiology since 1974
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| laperry
Forum Newbie
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The reason you probably haven't heard much about this particular vibrio species is because it is not pathogenic. Although, much like other pathogens it has the mechanisms to bypass host immune defenses, and also cause apoptosis of host tissues ( it uses virulence factors like TCT in whooping cough, rtx, and others). It is a symbiont! although the particular isolate in my picture is not a symbiotic isolate. fischeri inhabits temperate and subtropical waters around the globe and participates in symbioses with multiple species of squid and fish. the squid symbiosis has been studied in many ways for the last 20 years, and is highly specialized, so much so that isolates of vibrio fischeri from different locations (related squid from different locations, or water, or fish) have a difficult time colonizing squid. the v.fischeri in my picture is an isolate taken from seawater that I evolved for improved symbiosis by passaging it through a series of juvenile squid. Now I am recovering the fruits of those labors and trying to figure what their causes are. that may be about ten times more than you ever wanted to know, but if anyone is interested post more questions and i'd be happy to address them. thoughts, suggestions, and anything on this soft agar aggregation are also very welcome. (I used a pin replicator into a plate with 0.3% agar. I am screening for motility because it has been shown to be an important factor in squid colonization)
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