Penn Senior Barbara Biney Is Unlocking the Genetic Secrets of Heartworm-resistant Mosquitoes
By Erica Andersen
Certain mosquitoes don’t get heartworm, and Barbara Biney was keen to find out why.
Biney, a senior at the University of Pennsylvania, pursued the opportunity to work in the lab of Michael Povelones, an assistant professor of pathobiology at Penn’s School of Veterinary Medicine, beginning in her sophomore year. The lab studies the way the mosquito immune system kills invading pathogens like malaria, which may one day lead to new ways to curb the spread of these diseases.
“That’s what brought me to this lab,” says Biney, who was born in Ghana and grew up in Mountlake Terrace, Wash. “I was really interested in doing research in something that hit home.”
This summer, Biney completed research in the Povelones lab. She worked with two strains of the Aedes aegypti mosquito, the very same that made headlines in recent years for transmitting Zika, dengue and other human-afflicting diseases. One of these strains is used as a laboratory model for canine heartworm, though it is not a natural vector for the disease. The other is what scientists label “refractory,” or unable to pass along canine heartworm.
“Mosquitoes have their own immune system,” says Biney. “If the mosquito can kill off the pathogen before it bites someone, it’s not going to pass on the disease.”
The lab has an idea of which genes may be responsible for this resilience, and it was Biney’s job to suppress those genes to see whether the affected mosquitoes then become susceptible to heartworm. Normally, when a gene is expressed, messenger RNA carries a code of nucleotide bases from DNA in the nucleus of the cell to structures called ribosomes in the cell’s cytoplasm, where the sequence is translated into proteins. Biney spent her days making folded pieces of double-stranded RNA, which can be used to disable messenger RNA. By disrupting the flow of genetic information from DNA to protein, Biney was able to silence the genes that Povelones suspects are involved in the mosquito’s resistance.
She used special sequences called primers to tailor the dsRNA to certain genes.
“Primers clip onto the site that codes for the gene that you want to target,” Biney says. “You have to design a primer so it fits the right part of the genome.”
Once she was able to get the right primer, she could use the target gene’s template to synthesize, amplify and purify the dsRNA. She later injected this dsRNA into anesthetized resistant mosquitoes under a microscope.
Biney, a biology major, is also a track-and-field athlete. Sometimes, after she had set up an experiment, say a polymerase chain reaction to make copies of a particular segment of DNA, she’d leave the lab to do a workout before returning to check the purity of the reaction’s product. Her long days were filled with a mix of research, class, studying and training. Now in her final year at Penn, she says she’s proud of how hard she’s worked to get where she is.
“My friends are really understanding, and everyone knows me by now,” Biney says. “I do my work. That’s why I came here.”
As another track season begins she says, “I am still very excited about the things that I can do athletically.”
This past season the women’s outdoor track team placed in the top two at Ivy League championships. Barbara believes this level of achievement will continue into the next season, and she hopes to attend the NCAA championships.
Biney plans to apply to medical school and hopes to return to Ghana one day to work in a health-related capacity.
“I want to give back to my homeland in a context that I can excel in, which is health and medicine,” she says. She was only a year old when she moved to the United States but says her parents “definitely emphasized” her West African heritage. “I’ve been back three times,” Biney says. “It’s a big part of who I am.”
Her research at Penn during the summer was funded by the Jumpstart for Juniors grant, which provides research money for students during the summer following their junior year. It allowed Biney to do the science she loves and get paid for it.
“I’m not necessarily in a position where I can work for free,” she says. “The grant made it possible for me to stay here and spend a lot more time in the lab, and I’m very appreciative of it.”