Principal Investigator


Joseph P. Zackular, PhD

Principal Investigator
Assistant Professor of Pathology and Laboratory Medicine
Division of Protective Immunity
University of Pennsylvania
Children's Hospital of Philadelphia

B.S. - University of Massachusetts - Amherst, 2008
M.S. - University of Massachusetts - Amherst, 2009
Ph.D. - University of Michigan, 2014 - (Dr. Patrick Schloss Lab)
Postdoc - Vanderbilt University - (Dr. Eric Skaar Lab)

Joe is originally from North Reading, Massachusetts and he received his B.S. and M.S from The University of Massachusetts-Amherst. He earned his Ph.D. in Microbiology & Immunology from the University of Michigan in the laboratory of Dr. Patrick Schloss, where he studied the role of the gut microbiome in colorectal cancer. Joe did his postdoctoral training in the laboratory of Dr. Eric Skaar at Vanderbilt University where he studied the impact of nutritional immunity and dietary metals on Clostridium difficile infection.

Twitter: @joeyzacks


Research Staff


Jessica Hart

Research Technician

Jessi joined the Zackular lab as a Research Technician in November 2018. She earned her B.A. in Earth and Environmental Science from Temple University in 2017. At Temple, Jessi worked as a research assistant in the laboratory of Dr. Erik Cordes studying anthropogenic impacts to deep-sea corals. Prior to this, she studied plant-pollinator interactions of a local native wildflower affected by habitat fragmentation with Dr. Rachel Spigler. Jessi is from Reading, Pennsylvania.


Orlaith Keenan

Research Technician

Orlaith graduated from the University of California, Santa Barbara in 2019 with a B.S. in Microbiology. As an undergrad, she worked at Apeel Sciences, a company that develops edible coatings to extend the shelf life of fresh produce. While at Apeel, she isolated and identified fungal pathogens from moldy fruits and screened plant-derived molecules for antifungal activity against the pathogens. Orlaith is excited to start working with gut bacteria and learn about the various ways they impact human health.

Postdoctoral Research Fellows

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Arwa Abbas, PhD

Postdoctoral Research Fellow

Arwa is a postdoctoral researcher hailing from the Bushman Lab at the University of Pennsylvania. She graduated from Rutgers, the State University of New Jersey in 2012 with a B.S in Biotechnology and a minor in Biochemistry. While her undergraduate research focused on environmental bacteria, she studied the human viral microbiome in graduate school and successfully defended her thesis (without even needing the aid of a lightsaber) in the spring of 2019. Now, she’s eager to get back to bacteria in the Zackular lab! When she’s not at the bench (sometimes even then), she is often doodling.

Graduate Students

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Joshua Soto-Ocana

Graduate Student (CAMB-CB)

Every story has a beginning and Josh’s started in Puerto Rico. He graduated from the University of Puerto at Mayagüez in 2018 with a B.S. in Industrial Microbiology, a B.S. in Biology, and a minor in Biochemistry.  While his undergraduate research was focused on organic chemistry and biochemistry, he was always very passionate about cancer and microbiology. That’s why he decided to join the Zackular lab and the Cancer Biology graduate program at Penn. Josh is eager to investigate the metabolic crosstalk between the host, microbiota and immune system in colorectal cancer. When he is not at the bench he enjoys going to the beach, chasing waterfalls, biking, and working out.


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Alexander B. Smith

Graduate Student (CAMB-MVP)

Alex is a graduate student in the Microbiology, Virology, and Parasitology program. He comes from a small town in central PA and graduated with a B.S. in Biochemistry and Molecular Biology from Penn State University. During his undergrad, he studied the genetic basis for modifications made to E. coli lipopolysaccharide in the lab of Dr. Timothy Meredith. He’s excited to get his hands in the anaerobic chamber and start deciphering the interspecies interactions between C. difficile and Enterococcus. When he’s not in lab, Alex enjoys cooking, working out, and exploring Philly.



Undergraduate Students

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Paula C. Rangel

Post-Baccalaureate student

Paula is a premed post-bacc student at the University of Pennsylvania. She graduated from the University of California, Berkeley in 2018 with a B.A. in Spanish Linguistics, a B.A. in Molecular and Cell Biology, and a minor in Comparative Ethnic Studies. She is passionate about immunology and infectious diseases and has high hopes of becoming a family physician and serving Spanish speaking immigrants in California!



Mauricio Alvarez


Mauricio hails from Colombia and he joined the Zackular Lab as an undergraduate research assistant in the winter of 2019.  Mauricio is studying Biology and Chemistry at the University of Pennsylvania and is planning on pursuing an MD-PhD after graduation. When he is not studying or in lab, he also “enjoys” his time conducting physical chemistry research, training as a triathlete, or as member of the Penn Equestrian Team.


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Nile Bayard

Undergraduate summer student

Born and raised in Philadelphia, Nile Bayard is a rising sophomore at Haverford College. He is planning to major in biology and wants to pursue a PhD. While he isn’t sure exactly what he wants to study for his PhD, Nile is certain that he wants to conduct biological research now and in the future!


Rotation Students

Spring, 2019:

Joshua Soto (CAMB-CB)

Alexander Smith (CAMB-MVP)

Summer, 2019:


Ying Yang (CAMB-MVP)

Ying is an incoming graduate student of CAMB-MVP at the University of Pennsylvania. She earned her M.S. in Biotechnology from the University of Pennsylvania, where she studied the mechanisms of T cell responses during flu/bacterial co-infection. She was born and received her B.S. in China. She is interested in host-pathogen interactions and started a rotation in the summer of 2019 in the Zackular lab.


Lab pets



Website manager
Emotional support dog

Beaker is from Kalamazoo, Michigan.  He's 9 years old and when he's not in the lab he is usually sleeping, barking, or eating. His favorite thing to do is go on long walks and chase squirrels.



Creative design engineer

Erl is originally from Nashville, Tennessee.  He's 2 years old and when he's not in the lab he loves watching birds, playing with his brother, and meowing at the wall.  



Grants Administration

Gretchen enjoys sitting in the sun and chasing strings.

Research Openings

Graduate students:

The Zackular Lab is looking for excited and motivated graduate students to join the team. If you are a current member of the Immunology Graduate Group (IGG) or the Cell & Molecular Biology Group (CAMB), reach out to Dr. Zackular directly to discuss rotation and thesis projects. Prospective students interested in the Zackular Lab should strongly consider applying to the CAMB or IGG programs at the University of Pennsylvania.

Postdoctoral fellows:

We are currently looking for highly motivated postdoctoral fellows interested in the gut microbiota, host-pathogen interactions, and bacterial pathogenesis. Prospective postdocs interested in clinical, basic, or computational research in these areas of research are strongly encouraged to apply for a position. To apply, contact Dr. Zackular directly with a cover letter, copy of your updated CV, and the contact information of 2-3 references.

Research Technicians:

Research technicians work to maintain the day to day lab operations and have the opportunity to drive independent research projects. Currently, we are not looking for research technicians for the lab, but if you are interested in a research technician position in the future, contact Dr. Zackular directly or visit careers at CHOP for openings.

Undergraduate researchers:

The Zackular lab is committed to giving trainees at all levels the opportunity to gain research experience and receive mentorship. If you are an undergraduate student at the University of Pennsylvania and would like to work in the laboratory, reach out to Dr. Zackular directly. Undergraduate researchers will work along side other trainees in the laboratory and be given the opportunity to develop an independent research project or thesis project.