Painting with Microbes

Samantha Smith F01

Just a wink and a nudge to my favorite book “East of Eden” by John Steinbeck. I have a a pretty cross stitch of this at home, which admittedly looks a lot better. Perhaps I will stick to my day job and leave the microbe painting to those more artistic than myself.

I used the Eosin Methylene Blue Agar plate for this painting, hoping to achieve a stark different in coloration from the two sources I chose. The lettering and the vine were done with Escherichia coli.  This bacteria is gram negative so is not inhibited by the eosin or methylene blue of the medium. It also produced a deep black color with a metallic green sheen as it ferments lactose with strongly acidic end products. (The green sheen is actually quite pretty, though you can’t tell from the photo). The filigree and leaves are colonies of  Enterobacter aerogenes  which is also gram negative. It produces a pink color because it does ferment lactose, but the end products of fermentation are much less acidic than that of  E. coli.

I would like to add that I had a lot of fun in this assignment and seeing the variety of agar art from the ASM Agar Art Contests.


Painting with Microbes

Extending an Olive Branch – Kyle Callegari, BIOL 342 Sec. 1


Johnny Bravo – Kyle Callegari, BIOL 342 Sec. 1


Yin Yang – Kyle Callegari, BIOL 342 Sec. 1


For the first bacteria plate, on TSA medium, my intent was solely to become more comfortable with streaking a design on a solid medium plate.   I tested adding varied amounts of bacteria and played around with the amount of strokes before swabbing for more bacteria.   I additionally became comfortable using the different sides of the inoculation loop for different width strokes.   The TSA medium is not differential or selective.

The Eosin methylene blue agar is a selective and differential medium used to culture gram-negative bacteria.   Johnny Bravo’s facial features grew a dark purple color indicating rapid lactose fermentation.   This bacteria produces acidic waste quickly and in turn absorbed the dark dye.   The tan strains have remained uncolored because they do not ferment lactose, but rather remove amino acid groups from the lactose medium increasing the pH. I used S. marcescens, and E. aerogenes on this plate My intent with this piece was was to create a recognizable figure that recalls fond memories.

The MacConkey agar is a selective and differential solid medium designed to isolate gram-negative bacteria.   It has dye that indicates the fermentation of lactose by turning pink when the process is occurring.   I used S. marcescens and C. freundii on this plate.   The yin yang symbol represents inseparable and contradictory opposites, and dates back to the third century.   It is possible S. marcescens has a faster growth rate than C. freundii, and that is why the bacteria in pink didn’t establish as well.