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People: Team Members



Joshua Modell

Principal Investigator

Josh got his PhD from MIT in the lab of Michael Laub and did his postdoctoral work at Rockefeller University with Luciano Marraffini. Outside of the lab, Josh enjoys cooking, eating, ball sports, and constantly filling his rear bike wheel with air. Josh wonders whether there is a hole or if that’s simply what it’s like to be a bike commuter, riding and pumping, riding and pumping. Josh claims to be training for a half-marathon, but some question his dedication, most of all, his wife Cleo. Cleo mentioned that there is a 5k on the same day as the half-marathon, and Josh felt patronized, which is exactly what Cleo wanted. Now, everyone’s watching to see what he will do… | @jwmodell


Marissa Feeley

BCMB PhD Candidate

Marissa obtained her B.S. in Biology from Suffolk University in Boston, MA. She worked at the Broad Institute conducting CRISPR screens in human cancer cell lines before returning home to Baltimore, MD to dip her pipette into microbiology. Outside of lab, Marissa enjoys rock climbing, biking, visiting local breweries, going to the beach, and confidently singing the wrong lyrics to songs. She also collects musical instruments that she intends to teach herself, only to find she’s instead mastered the art of collecting dust on said instruments. Maybe if she didn’t binge true crime shows and podcasts, she’d actually have the time to learn.


Joshua Garcia Colon

BCMB PhD Candidate

Josh earned his B.S. in Cellular and Molecular Biology from UAGM in San Juan, Puerto Rico. He then did his post-baccalaureate work at UNC Chapel Hill where he studied the contact-dependent growth inhibition system of Burkholderia thailandensis. He came to graduate school with an interest in bacterial defense mechanisms and is now at the front row watching bacteria/phage battles on his day to day. In his free time, Josh enjoys being active, doing sports, relaxing at a scenic spot, or driving someplace new.

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Nick Keith

BCMB PhD Candidate

Nick received his BS in Biology from the University of North Carolina - Chapel Hill. Outside of lab, he devotes the majority of his time to planning his next backpacking adventure (both the hiking and world-traveling types). Since he’ll never actually be able to find the money or time for those trips, he instead spends his free time playing the banjo and other instruments, making home renovations, and trying to clicker train his stubborn cat. If all goes as planned, he recommends following his newly-trained adventure cat’s Instagram influencer account.


Katie King

BCMB PhD Student

Katie received BAs in Biology and Italian from UNC Chapel Hill where she studied how coagulation factors influence obesity and its comorbidities. She now spends her time at Hopkins warmed by the flame of a truly giant bunsen burner while exploring the rich lives of famously bloodless microbes. Outside of lab she can be found climbing (and falling) off rock walls, cooking questionable recipes, and perusing a graveyard of past hobbies that grows by the week. She has put her liberal arts experience to use by learning just enough Italian to say that un giorno governerà il mondo e tutti i microbi all’interno!


Melina Mohammadi

Undergraduate Researcher

Melina is a sophomore studying Chemical and Biomolecular Engineering at Johns Hopkins University. Outside of lab, Melina enjoys gathering with friends to play games, try out new restaurants, and steadily work through their movie to-watch list. She recommends Ferris Bueler's Day Off for a laugh, and The Grand Budapest Hotel for both laughs and tears. At the end of the day she can be found sharing life updates and advice with her mom and sister, catching up over video call with her family in Iran, and finally playing some Stardew Valley in bed before calling it a night. If she was as diligent in real life as she was at taking care of her pretend farm, she would become an unstoppable force. But perhaps the world isn't ready for that just yet.

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Rhett A. Snyder

BCMB MD/PhD Candidate

Rhett received his BS in Microbiology at Indiana University where he discovered his love for bacteria starting with Caulobacter crescentus. After studying the human immune system for a while, he decided to go back to his prokaryotic roots and research the (arguably cooler) bacterial immune system. When not in lab, Rhett is most often found caring for his vastly growing indoor jungle. The genus hoya is currently his favorite with over 150 species in cultivation. He hopes to one day utilize his honed skills from lab to hand-pollinate and create unique hybrid crosses. Outside of bacteria and plants, Rhett enjoys a variety of board games, time spent near any water source, and quiet evenings with his partner, Levi, and three cats, Jinx, Nixi, and Garbo. 


Peter Sparklin

Research Technologist

Peter received his M.S. in Bioinformatics from University of Maryland Global Campus. Outside of his budding interest in molecular biology and coding, Peter loves growing flowers, hiking, and writing bad poems about dogs and cats to put in Rachael's lunchbox. He can proficiently operate a backhoe, snowplow, and/or chainsaw if the situation calls for it


Marie Stoltzfus

BCMB PhD Candidate

Marie received her BS in biology from Millersville University where she studied gene expression in squid muscle. At Hopkins, she transitioned to molecular microbiology, significantly decreasing her risk of being inked. When she isn’t pipetting or troubleshooting NGS protocols, Marie enjoys baking for friends and lab mates, hiking, and dabbling in new hand-crafts whenever the opportunity arises.


Sarah Voss

BCMB PhD Candidate

Sarah received her BS in Biochemistry at Texas State University before packing everything she owns into her Prius and driving across the country to join the BCMB program and the Modell lab. When she’s not in lab, she is probably in her Prius. Going anywhere that’s not home and doing anything that doesn’t cost too much money. Sarah really has to save her money because she spends it all on iced lattes. Yes, it would cost less if she just made coffee at home or used the fancy espresso machine in lab, but we all know it tastes better when someone else makes it. And Sarah is definitely drinking lattes for the taste- not because she’s addicted to caffeine or anything.

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Adam Wilson

Undergraduate Researcher

Adam started his college journey as a proud Lumberjack at Northern Arizona University, before transferring to Johns Hopkins. He has a habit of switching majors, but seems to have settled (finally) into Molecular and Cellular Biology. Once upon a time, you could find Adam climbing a big wall in Yosemite or skiing from the summit of Oregon’s Mount Hood, but in his new Baltimore environs, he attempts to keep up his skills at the local climbing gym. He enjoys binging Netflix, reading sci-fi and fantasy, and playing D&D. He also likes pizza and coffee, though not necessarily together.

Former members

Rachael Workman - BCMB PhD Student, 2018-2023

Alex Tsantilas - Undergraduate Researcher/Research Technologist, 2021-2023

Philipp Andesner - Research Specialist, 2021-2023              

Bella Cabrera - BSI-SIP Summer Intern, Summer 2020; PREP Scholar, 2021-2022              

Sakshi Chavan - Biotechnology Master's Student, 2019-2021

Leo Graeff - Undergraduate Researcher, 2018-2020

Binh Nguyen - Research Technologist, 2018-2020

Teja Pammi - Research Technologist, 2018-2020

Suzanne Sebald - 2018-2020

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