This gorgeous art was made with a surprising substance: live bacteria

Agar plates changed the way scientists cultivate tiny life. Now they are the canvas for a growing school of art.Thursday, 21 November 2019

Our relationship with microbes has always been complicated. We fear them as “germs,” the organisms behind disease, yet embrace them for their role in the food web and for producing fermented food products. When Antonie van Leeuwenhoek (1632-1723) first saw microbes under the microscope in the 1670s, he became known as the father of microbiology. But centuries passed before scientists could more easily grow them in the lab. Now, microbial growth is at the centre of what’s called agar art—using the common lab growth medium as a canvas and applying growing organisms to create what look like sketches, paintings, and even 3D artworks.

For the last five years, the American Society of Microbiology (ASM) has been running an agar art competition. This year brought in 347 entries across categories for scientists (Professional), non-scientists (Maker), and children (Kids). Entrants submitted photos of their agar art creations, ASM staff judged the submissions in each category, and the public voted on social media to award People’s Choice honours.

This year's winners, announced today, include a depiction of a Koi fish and a lotus flower by Arwa Hadid from Oakland University (Professional); Hungarian folk art by Zita Pöstényi from SYNLAB Hungary Ltd. (People’s Choice); a bacterial self-portrait by Korey Abram (Maker), and “The Circle of Life” representing the connectedness of the world by Kate Lin (Kids).

Growing microbes

Centuries ago, microbiologists grew bacteria on food ranging from potatoes to coagulated egg whites and meat. Robert Koch (1843-1910), known for a series of principles linking microorganisms to diseases, wanted to improve bacterial cultivation by using something that was solid, transparent, and could be sterilised. Gelatin seemed like a good choice, but it was problematic: It liquifies at 37°C (98.6°F), the temperature used to grow many microorganisms.

Angelina Hesse (1850-1934), an assistant and illustrator in Koch’s lab in Germany, discovered that an ingredient used in jellies and puddings could be used to create a better growth medium. That ingredient was agar, a gelatinous substance isolated from seaweed.

She mentioned this to her husband, who also worked in the lab. He reported the idea to Koch, who eventually used it to cultivate Mycobacterium tuberculosis, the bacterium behind tuberculosis. Unfortunately, Hesse never received credit for her discovery, but her contribution revolutionised the way scientists grow microbes.

To create agar plates, agar powder is mixed with nutrients and water, heated under pressure to sterilise the mixture, and poured into shallow dishes. When cooled, it solidifies into a smooth, semi-solid surface for bacterial growth, an upgrade from the foodstuff scientists were previously using.

Scientists have created a variety of agar plates to meet the needs of a diverse set of microorganisms, a colourful assortment that perfectly serves as an unconventional canvas for living art. Alexander Fleming (1881-1955), the scientist who discovered penicillin, was one of the early adopters of agar art. However, agar art did not gather steam for decades.

Art meets science

The ASM Agar Art Contest was born from a “pic of a day” series on social media. When an image of agar art from Rositsa Tashkova went viral in December 2014, ASM staff had an idea. By the following summer, they had launched their first agar art contest.

“The idea was to get our members involved in doing something fun that showed the outside world that scientists can be creative,” says Katherine Lontok, ASM’s public outreach manager. In its first year, the contest received 84 submissions. Since then, the contest has evolved in many ways.

“People are definitely getting every year more and more intricate with it, incorporating things like 3D agar and using spores and all different kinds of organisms,” says Lontok. In the previous years of the contest, subjects ranged from the natural world to the abstract, and included a facsimile of Vincent van Gogh’s "Starry Night".

Painting with microbes

Like other art forms, agar art involves some planning: coming up with the idea, envisioning the composition, choosing the medium, and choosing the colours. But it also involves a lot of waiting and patience. The microbes are painted onto the agar, invisible to the human eye. They then multiply on the agar to unveil the painted artwork within a couple days, in most cases.

Some microbes produce colour naturally. Streptomyces, which produce many of our antibiotics, release blue-green pigments in alkali conditions and red pigments in acidic conditions. The well-known Escherichia coli produce a beige colour. Microbes of all colours can be found right in our backyards. One agar artist collected soil from their backyard, diluted it, and spread it on the agar plate to see what could grow. After a period of growth, the plate revealed a palette of colours that they could use to create the art, in this case a purple and yellow butterfly.

Other microbes are genetically modified to fluoresce in bright pinks, greens, and blues. One submission this year included a fluorescent tree made from Bacillus subtilis, a soil microbe that is typically beige. By introducing genes for green and red fluorescent proteins, the artists could customise the appearance of these bacteria for their artistic needs.

Another artist, Janie Kim from Princeton University, combined both naturally occurring and engineered microbes to create “Marine Universe” representing the symbioses between bacteria and sea sponges, squid, fish, and algae. One type of bacteria came from a lab strain engineered to produce a blue colour, while the yellow and white bacteria used came from the artist’s skin. The artist mixed the different species of bacteria to create the green colour.

“The two bacteria are able to exist together to create art, much like marine symbioses themselves,” says Kim.

Beyond painting microbes onto the agar with toothpicks or inoculating loops, agar artists have used complex tools to create their pieces. The winners of the 2017 contest “printed” nanodroplets of yeast culture onto an agar plate using a robotic liquid dispenser; each droplet produced a separate yeast colony to create a sunset scene over the ocean. The artists called this biopointillism, after the Pointillism technique developed in the 1880s by artists including Georges Seurat.

Hello, world

Though microbes surround us all the time, most are unseen. Agar artists change that, revealing an invisible world limited only by the microbial palette and the creator’s imagination. Agar art is now incorporated into Danish art curricula and was featured at an event during the 2019 United Nations General Assembly. It’s also made in DIY biology labs, and the ASM Agar Art Contest has inspired other contests around the world.

“This is a great public outreach tool,” says Lontok. “It shows the beauty and diversity of microbes,” a side of microbiology that has historically been overlooked.

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