As part of Global City Sampling Day, teams of University of Miami students fanned out across Miami-Dade County on Monday, June 21, 2021, taking microbial samples on surfaces at each of the 23 Metrorail stops. Their efforts will help create a map of the community of microorganisms that inhabit the city.
Metrorail’s Civic Center station bustled with rush-hour activity. Then, the two University of Miami students showed up with packets of swabs and collection vials.
One of them, Umer Bakali, quickly got to work, dipping a swab into a reagent, then rubbing it vigorously back and forth on the buttons of a ticket kiosk. His teammate, Chitvan Killawala, stood nearby, recording the process on a spreadsheet while holding one of the vials into which the swab would be placed for safekeeping and preservation.
The two then swabbed an escalator handrail and an elevator button before hopping aboard a southbound train for the Culmer and Overtown stations, where they would repeat the entire routine, drawing stares from curious onlookers.
Bakali and Killawala were two of 15 University of Miami students and employees who participated in Global City Sampling Day (gCSD) on June 21.
From Boston to Buenos Aires, Cairo to Copenhagen, Miami to Marseille, and Seattle to Singapore, teams of researchers and citizen scientists fanned out across 54 cities on five continents to collect samples of DNA, RNA, and microbes from surfaces at airports, subways, bus terminals, and other mass transit stations.
The samples—all 6,000 of them—will be packaged and shipped to Weill Cornell Medicine in New York City. There, researchers who lead the international consortium MetaSUB (short for Metagenomics and Metadesign of Subways and Urban Biomes) will spend several months analyzing them using a technique called shotgun sequencing—which will detect microbes, including bacteria and viruses, that use DNA or RNA as their genetic material.
The data will augment an ongoing microbial census of the community of microorganisms that inhabit each city. That census, which MetaSUB has been compiling since 2015, includes new molecules and enzymes that could potentially be used in diagnostic, industrial, or therapeutic applications, according to Christopher Mason, a professor of physiology and biophysics at Weill Cornell Medicine and the co-founder of MetaSUB.
“For example, the more than 800,000 CRISPR arrays we recently found can be used as new tools to remove disease-causing mutations in patients,” said Mason, referring to regions in the bacterial genome that can help defend against invading viruses.
And in the age of COVID-19, fighting viruses is something that hit close to home for many of the University of Miami students who collected samples at each of the 23 Metrorail stations during gCSD.
“The elephant in the room is definitely the COVID-19 pandemic,” said Bakali, a Ph.D. student in biochemistry at the Miller School of Medicine, who commutes on Metrorail each day. “We know, of course, that COVID-19 is a virus. But that doesn’t make it any less important that we take into account what people interact with every single day as they’re going through their methods of transit.”
For Killawala, gCSD allowed him to visualize what he wants to become in the future, he said. The graduate student in biomedical engineering, whose 74-year-old grandfather in India died from complications of the coronavirus, is developing electronic sensors that will analyze molecules in a patient’s breath to detect diseases.
“We’ll be able to ‘smell’ physiological problems we can’t see, much like what we’re doing with this sampling of microbes that are naked to the human eye,” Killawala explained.
