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Movers And Shakers

Patrick Ymele-Leki and Jamel Ali want to understand how bacteria form impenetrable biofilms

These friends and chemical engineers hope to find new insights into biofilm biochemistry to guide the development of new antibiotics

by Frieda Wiley, special to C&EN
February 22, 2021 | A version of this story appeared in Volume 99, Issue 6

Patrick Ymele-Leki and Jamel Ali met in 2011, when Ali was a graduate student pursuing his master’s degree in chemical engineering at Howard University and Ymele-Leki had recently joined the same department as an assistant professor. It’s unusual for friendships to be forged across the student-professor divide, but since then, the pair have stuck together like two microbes in a biofilm.

A photo of Patrick Ymele-Leki.
Credit: Michael A. McCoy
Patrick Ymele-Leki

Patrick Ymele-Leki

Home countries: France and Cameroon

Education: AS, Montgomery College, 2001; BS, 2003, and PhD, 2009, University of Maryland, Baltimore County

Current position: Professor of chemical engineering, Howard University

Go-to stress reliever: Movies and animes

Book that made an impact on him: Makes Me Wanna Holler: A Young Black Man in America, by Nathan McCall

A photo of Jamel Ali.
Credit: Mark Wallheiser/FAMU-FSU College of Engineering
Jamel Ali

Jamel Ali

Hometown: Washington, DC

Education: BS, 2011, and MS, 2013, Howard University; PhD, Drexel University, 2016

Current position: Professor of chemical and biomedical engineering, Florida A&M University–Florida State University College of Engineering

Go-to stress reliever: Classical music

Best professional advice he’s received: Find a field that you’re passionate about and one that is not oversaturated.

These films, which bacteria make by releasing sugars, form a barrier impenetrable by many molecules and help make the microbes resistant to antibiotics. In August of 2020, the National Science Foundation awarded Ymele-Leki and Ali—now a professor at Florida A&M University–Florida State University College of Engineering—a grant to study the detailed mechanisms by which bacteria create these biofilms.

Little is known about how biofilms form. Ymele-Leki and Ali hope to uncover the details of how the flow of surrounding fluids affects biofilm formation early in the process. In the bloodstream, the gut, and environments such as groundwater, water treatment systems, catheters, ship hulls, and industrial piping, bacteria experience mechanical forces caused by the flow of liquids.

Ymele-Leki and Ali are evaluating how external flow affects the microbes’ ability to stick to surfaces and the initial distribution of bacteria on surfaces. Next, they’ll measure the forces that flow exerts on biofilms and how these bacterial interactions drive biofilm formation.

“These flows have a huge impact on the ability of bacteria to stick to surfaces, stay firmly attached, and grow,” Ali says. Bacteria have power in numbers. When they congregate in biofilms, they gain properties they do not possess individually. For example, thanks to enhanced cell signaling and changes in gene expression, microbes living in biofilms are up to 1,000 times as resistant to antibiotics as individual cells are. Ali says he hopes this research will provide fundamental insights into how a bacterium’s external environment influences its survival and interaction with its microbial kin.

Ramesh C. Chawla, a chemical engineer at Howard University, says Ali and Ymele-Leki have a lot in common—and not just their research interests. “They are both diligently committed to their work, inquisitive yet patient, likely to come up with out-of-the-box approaches to tackling major scientific challenges,” he says. The pair work on more than science. Their personal backgrounds drive their passion for outreach as well. Both, Chawla says, are “equally passionate about mentoring a younger generation of scientists and developing outreach programs for underrepresented middle and high school students.”

The scientists bonded when they met because they both have international backgrounds. Born in France to parents of Cameroonian descent, Ymele-Leki immigrated to the US to go to college. Ali was born in the US to an Indo-Trinidadian father and an African American mother. At the time, his father was pursuing a graduate degree at Howard, while his mother was working for the Federal Bureau of Investigation. Ymele-Leki and Ali pursued similar academic routes, earning PhDs in chemical engineering and then teaching at historically Black colleges and universities (HBCUs).

In their individual labs, the pair work on complementary aspects of microbiology. Ymele-Leki is searching for new antibiotic candidates. Ali, with the help of middle and high school mentees in his lab, is investigating how nutrient types and concentrations affect the virulence of various microorganisms.

The researchers hope their work will ultimately pave the way for new antibiotics that can fight resistant bacteria. Their achievements, Ymele-Leki and Ali say, are a by-product of the chemical bond between friends who became colleagues.


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