Painting with microbes

I had real trouble deciding on what to paint on with my microbes. You could say I had painters block. It wasn’t till I was pulling up to lab that I was inspired. I decided to paint stop signs to represent microbes telling us to stop underestimating them.

The first picture is the MacConkey agar plate. For this one I wanted to make a stop sign with  white  edges and letters. To contrast this I wanted to make the middle red. To do this I used the acidic lactose product  producing bacteria Citrobacter freundii  to lower the pH of the middle causing the agar to turn pink. For the white I used  Proteus mirabilis  an ammonia producing bacteria to raise the pH and turn the plate yellow-whitish. Both of these bacteria had to be gram negative since the agar selects for gram negatives.

The second picture is of the eosin methylene blue agar (EMB), which also selects for gram negatives, as well as turning lactose digesting bacteria black or dark red. For this picture I just wanted to make a stop sign with black letters and boarders, using the red agar plate to fill in the red in the middle. The bacteria I used was the  Citrobacter freundii, as it digests lactose and is gram negative.

The last picture is of the TSA plate where I used the red bacteria  Serratai marcescens  to  draw the boarder and letters. I miss judged the size of my letters and the P didn’t really fit.