Image 1. R2A with 0.01% of methylene blue.
At STC, we have hardly ever touched on AgarArt, a popular classroom topic among microbiology students and teachers (we see you, Mark!). In the unlikely case that you do not know AgarArt, you find numerous examples on Twitter with the hashtag #AgarArt. And, behold, ASM even holds an annual ASM Agar Art contest.
In AgarArt, budding and experienced microbiologists live out their creativity, using microbes basically like paint to generate a colorful image on a support that promotes growth. Perhaps we have a slightly different idea of AgarArt, namely that microbiologists just provide microbes with a "canvas" on which these can then show their creativity during growth on it. Surprises guaranteed! Recently, we learned from one such approach on Twitter, and here are now a few more words...
by Manuel Porcar
At DARWIN, beyond our main commercial goal of developing microbial solutions for the industry, we are also trying to develop new artistic bio-inspired languages in which microorganisms may play a key role. In the frame of such exploration, we are developing culture media that combine the nutrient requirements of conventional microbiological media with a format and colors that are more visually appealing. The images correspond to square Petri Dishes filled with microbiological media R2A or TSA, with added colorants as indicated in the figure legends.
Image 2. TSA with 0,2% of food-grade green colorant
R2A agar medium agar, 15 g/L, casein acid hydrolysate, 0.5 g/L, dextrose, 0.5 g/L, dipotassium phosphate, 0.3 g/L, magnesium sulfate, 0.024 g/L, proteose peptone, 0.5 g/L, sodium pyruvate, 0.3 g/L, starch, soluble, 0.5 g/L, yeast extract, 0.5 g/L.
TSA agar medium agar, 15 g/L, casein peptone (pancreatic), 15 g/L, sodium chloride, 5 g/L, soya peptone (papainic), 5 g/L.
The colorants were added mainly to add contrast to the often pale and/or transparent microbiological media. The solid media were inoculated by indirectly stamping human skin (hand). A stamp-like device − think of Esther Lederberg's replica plating technique − was placed on a volunteer's hand and then stamped on the media. The plates were incubated in a storage room for a few weeks, and then some colonies forming "paths" were detected. By microscopic observation, mites were found to have colonized the dishes. At this point we considered to repeat the experiment but, since the purpose of this inoculation was aesthetic, and in order to introduce some more drama and "action", the dishes were kept in the same room and, as a result, mites continued to spread the colonies all along their paths. Petri dishes were incubated in total for two months at room temperature, and then pictures were taken (Note that the tiny yellowish stripes on most of the bacterial colonies in Image 1 came as reflections from the ceiling lights (neon tubes) in the lab).
Image 3. TSA with 0,01% phenol red
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Manuel Porcar is CEO of DARWIN, and performed the experiments together with Carmen Alonso, head of communication and marketing, and Manuel Gómez, R&D manager.
Image 4. TSA with 0,01% bromocresol purple
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