4/1-4/5 Biofilm Formation in D. Metalli

 D. Metalli is reported to form a biofilm when grown in a nutrient rich broth such as TGY, however we had yet to try this since our focus was on the biochemical tests which were all conducted on TGY and R2A plates. So, once we heard that this was a characteristic belonging to D. Metalli we had inoculated some of the bacteria into a 25mL flask of TGY and let it sit the in shaking incubator for 24-48 hours. After 48 hours of incubation in the shaking incubator there seemed to be no presence of a biofilm. There were no changes in the morphology when seen under a Gram Stain as well. I had asked one of the mentors about this and he suggested that I try leaving the flask in the incubator that doesn’t shake and leave it in there for 24 hours to see if any change occurs. After 24 hours there was a film like substance on the bottom of the flask that I had not seen before in any other species of Deinococcus. 

Visible Biofilm Formation at Bottom of Flask (1)


Visible Biofilm Formation at Bottom of Flask (2)




 After viewing this biofilm on the bottom of the TGY flask I had done a gram stain to see if there was any difference I could observe in the morphology of D. Metalli. At first there was not much that I could see that would suggest any major differences in the morphology, but on the second gram stain I could see that the cells weren’t uniform as they usually are. They were sort of stringy and filamentous, and we could see what we believe to be some of the biofilm. The reason this was so interesting to us was because biofilm formation is not a common characteristic among the Deinococcus genus and only occurs in a few other species within the genus. 

Biofilm Formation in D. Metalli
In the center of the picture you can see what we believe to be the biofilm and all around the biofilm are the cells that are not homogenizing to the nutrient rich broth and making that stringy structure that I previously mentioned. However, the biofilm is somewhat weak and will eventually homogenize to the broth if it is shaken enough. This sets it apart from D. Sonora since Sonora forms a sort of plaque that will not homogenize to the broth. 

Due to the lack of strength believed to be observed from this biofilm in D. Metalli we had hypothesized that if grown in a broth that was not nutrient rich, such as R2B, then this biofilm would not grow. We would also like to see if this species can be transformed. However, this testing would have to wait for a few weeks since in the next week we were focusing on the coming conference from the Arizona Nevada Academy of Science. 



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