Impacts of two bacteria in a plate or fight of bacteria !!!

Impacts of two bacteria in a plate !
Or fight of bacteria !!!

All of this experiment begin because in the real life we observe all the times a lot  of bacteria in the same place, but in our laboratory we never look different type of bacteria in the same !

So i asked to me, what can change if we put two bacteria together, and the answer is : the size, the shape and the colors of the colonies can change, if they have less nutriments near or because the other bacteria rejects things in the area.

I also observe the movements of my bacteria, because in my hypothesis if they have less  nutriments in a part of the plate, and if the bacteria can move to go in a place with more nutriments, they do it. 
To be able to move, the bacteria who I choose need to have less percent of agar, like 0,7 % (what i use).

So to see all of this, i create different kind plates and I use two specie of bacteria, the Salmonella typhimurium in yellow and the Serratia marcescens in red ! 

The two first are my controls, to have a referent point for my colonies !

The third is here to see what happend when the colonies of my two bacterias are closed, but not in contact (at the beginning, before the move of the colonies).

The fourth, not really clear on this, is to see what happend if we put the different colonies on one quarter of the plate for each bacteria, but if they have nothings except food in the other parts of the plate.

And the last one is to see what append, when the colonies are mixes in the plate ( colonies closed and everywhere in the plate.)

And at the end !!!!!

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Lot of things doesn’t work :C

 After put my plate at 37°C in the incubator, and after one day/night i have, that kind of thing :

Plate separate in half, with S. marcescence and Salmonella t

On my plates i was no able to disctinct the singles colonies, so i can't observe the size or the shape....... but we can see the movement and the colors of the colonies !

In this plate we see, the S.marcescence (in red ) move on grow a the place of the Salmonella t (in yellow/white), and colonize their place where the two colonies are in touch. 

Here, we can't see if the Salmonella t move, but in my plates separate in quarter .... 

Plate separate in half, with S. marcescence and Salmonella t

Whith this plate, we see the movements of the salmonella who go on the colonies, and we can see the salmonella move to ! But we observe the salmonella, on the empty place of the beginning (They have nothings in the parts with the point at the beginning of the experiment).

So my two bacteria move in the plate, and like i expected, the Salmonella t grow on the part with only nutriments, and (we have this impression) stay far of the S.marcescence colonies !

So this two bacteria have a pattern when they moves, the marcescence colonize the other bacteria, and the Salmonella t try to escape and move to have more nutriments.

Louise Jacquot septembre 2016

If you want to no more about Salmonella t and  S marcescence! 

      

          A field guide to bacterial swarming motility: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135019/

       Lot of information about S marcescens : https://microbewiki.kenyon.edu/index.php/Serratia_marcescens

         Informations abour Samonella typhimurium :https://microbewiki.kenyon.edu/index.php/Salmonella