Shelf Life 11: Green Grow the Salamanders

"We maintain about 80 live cultures of microorganisms, including algae. And about half of them are unique to our collection." 

-Eunsoo Kim, Assistant Curator in the Division of Invertebrate Zoology

Collecting The Invisible

The Museum’s collections house many eye-catching items, from the towering Tyrannosaurus to striking totem poles. But there is also a whole category of significant specimens that are imperceptible to the naked eye. We’re talking microbes: single-celled organisms stored in petri dishes or on glass slides. 

Model of the Actissa princeps made of blown glass.
A blown glass model of Actissa princeps, from the Museum’s collection. This model is still on display in the Hall of Biodiversity.

Microbes at the Museum

This episode of Shelf Life looks at how Museum researchers are currently studying the surprising role single-celled algae play in the life of the spotted salamander—and comes on the heels of the opening of a new exhibition, The Secret World Inside You, that is all about the intricate relationship between humans and the invisible microbes that live on us and in us.

But the Museum first began collecting microbiological specimens and creating exhibitions about the roles of microbes in human health more than a century ago.

Two children and an adult look at and interact with a digital Museum exhibit about microbes.
Now, visitors can "feed" digital microbes at The Secret World Inside You. 
Denis Finnin/© AMNH

In 1908, the Museum organized an exhibition about tuberculosis, then a common disease and one of the leading causes of death worldwide. Many New Yorkers of the time would have been painfully familiar with the symptoms of the highly contagious illness and its dire consequences.

Glass model of a microbe, shaped like a radial circle.
Elegant glass models were an early way of displaying microbes. 
AMNH/Library Archives

Far fewer were acquainted with the cause of the deadly disease: Mycobacterium tuberculosis, a strain of infectious, airborne bacteria that attacks the lungs. New Yorkers were so eager for more information about the infection, and about the invisible invaders that caused it, that lines for the Museum’s exhibition snaked around the block. Up to 10,000 visitors saw the show in a single day. 

Historical image of long line of people waiting to enter building with sign reading: International Tuberculosis Exhibition.
In 1908, visitors lined up around the block to see Museum’s exhibition on tuberculosis. 

The staggering success of the tuberculosis exhibition spurred the creation of the Museum’s Department of Public Health (DPH), which focused on producing exhibitions and educational materials about the biology behind food safety, water purification, and urban sanitation. One exhibition, developed to educate the public about the spread of diseases, featured a giant model of the malaria-transmitting Anopheles mosquito that’s still on display today.

Large model of an Anopheles mosquito, 75 times normal size of the insect.
The Anopheles mosquito model in the Hall of North American Forests was originally part of an exhibition on how diseases spread.
D. Finnin/© AMNH

In addition to public education, the new department’s curator, Charles-Edward Winslow, also pushed for better ways to study the organisms that caused diseases. His efforts led to the creation of a collection of microscopic life, which Winslow called the Living Museum, aimed at helping researchers cultivate, study, and classify different types of microorganisms. Winslow solicited live cultures from all over the country. Within two years, he had gathered 578 bacterial strains and provided 1,700 cultures to researchers at more than 120 labs and universities.

Man in a suit sits in a chair, shown in profile.
Charles-Edward Winslow oversaw the Museum's Department of Public Health.

Like other collections, the Living Museum designated type specimens that would serve the same purpose as their counterparts in collections of fishes, insects, or dinosaurs—offering a guiding and definitive specimen against which others could be compared. According to Winslow, it was “the first attempt in this country to standardize these life forms through museum methods.” 

A Foundational Collection

The Living Museum—which became known as the Winslow Culture Collection—included some of the most virulent germs around, including bacteria known to cause typhoid, cholera, and, of course, tuberculosis. But it also included beneficial microbes like those used in the production of yogurt, underlining humanity’s complex relationship its microbial neighbors. 

Clusters of Mycobacterium tuberculosis specimens.
Cultured specimens of the bacteria Mycobacterium tuberculosis
Courtesy of Centers for Disease Control

When the Department of Public Health was later folded into the Department of Public Education, the Museum’s first-of-its-kind culture collection lived on. In 1925, it moved to a new home at the Army Medical Museum in Washington D.C., where, under the care of the Society of American Bacteriologists (now the American Society of Microbiologists), it became the basis for one of the most important collections of microbial life on the planet: the American Type Culture Collection (ATCC).

Today, when researchers want a sample of an existing microbe species to study, or to describe a new one, they turn to the ATCC. Winslow's library of microbial type specimens has grown and flourished and become the specialized collection he envisioned nearly a century ago, and much more. What began as the Living Museum has become an active and widely used clearinghouse for microbial specimens, cell lines, and more, supplying scientists doing microbial research and medical studies with materials that are central to their work. 

Microscopic Marvels

Winslow’s collection of cultures, stored in petri dishes, glass slides, and vials full of glycerol, was the Museum’s first collection of microbes, but not its last. Today, the Museum is home to a number of collections of microscopic life.

Among these, the oldest is the Kirby-Cleveland collection, which details the microbes that live in the guts of termites and make it possible for these wood-eating insects to thrive on their specialized diet. Assembled beginning in the 1920s by entomologist Harold Kirby and curated by a number of his colleagues across the country following his death, the collection arrived at its permanent home in the Museum in 1991. In 2000, these specimens were joined by a similar collection assembled by late Harvard entomologist L.R. Cleveland.

The Kirby-Cleveland collections consists of thousands of specimens on slides, as well as photographs, illustrations, and even blown-glass models of gut bacteria. These specimens helped propel the modern study of symbiotic relationships and are still consulted by researchers today.

“This collection presages the founding of the field of symbiosis. Before the ability to sequence DNA, researchers would pick up a termite, squeeze out its poop, and find a lot of microscopic life, like protists and bacteria, that let it feed on just wood,” says Susan Perkins, associate curator in the Museum’s Division of Invertebrate Zoology.

Illustrations of termites and wood roaches of various sizes.
 Illustrations of some of the termites and wood roaches the microbes in this collection came from. 

Betsey Dyer, a professor of biology at Wheaton College who has worked in the collection, agrees. “The Kirby collection is one of the most complete collections… of a morphologically complex microbial group that diversified into thousands of species,” Dyer says.

Kirby’s collecting also led to the discovery that geography can shape the makeup of a termite’s gut population, Perkins says, pointing out that termites from Africa have distinctly different microbial membership than those in America.

The Museum also has a living collection of single-celled algae and hosts active research on their surprisingly complex biology. In 2012, Assistant Curator Eunsoo Kim showed that some algae don’t live by photosynthesis alone—they also hunger for an occasional bite of bacteria.

New information about microbes isn’t just present in collections devoted to them, though. Perkins points out that, for instance, the Museum’s growing Ambrose Monell Cryo Collection (AMCC) of frozen tissue samples holds more than meets the eye. 

“Because we have these tissue samples, we also have the microorganisms that live in that tissue,” says Perkins, who has harvested the malaria-causing parasites she researchers from the frozen tissue of bats and lizards in the AMCC. “We have specific microbe collections, but really, the entire collection is available for study.”