Department of Environmental ToxicologyStudent News

Dogs have many jobs, but one you may not expect is identifying grapevines coated in a destructive and highly contagious fungus. Although dogs can detect serious vine infections by smell, scientists don't know exactly what odor molecules are triggering the response.

Researchers are now analyzing volatile chemicals emanating from grape leaves infected by a fungus called powdery mildew with the goal of improving training for vineyard canines.

Nayelly Rangel, a graduate student at Texas Tech University, will present the team's results at the Spring meeting of the American Chemical Society (ACS).

"Powdery mildew is one of the most contagious diseases that affects grapevine plants," says Rangel. "It reduces plant growth, fruit quality and quantity, and it can lead to a decline in wine quality."

The current method to identify an infection relies on humans looking for tell-tale patches of gray powder along plant leaves. But, by then, the condition is usually serious and requires large amounts of fungicide to eradicate.

Past research showed that dogs can identify powdery mildew by smell. But not much is known about the chemistry of what these animals smell, or whether the plants' odor profile changes as the infection progresses.

"Our four-legged friends don't talk, so we're trying to understand what they are encountering when they're sniffing," says Paola Prada-Tiedemann, a professor of forensic science at Texas Tech University who is leading the study.

So, the researchers set out to identify which volatile organic compounds, or airborne scents, grapevine leaves give off at different stages of powdery mildew infection.

First, the team needed a technique that would keep leaf samples intact for dog training. So, they placed a leaf inside a vial and inserted a tiny absorptive fiber into the vial to pick up chemicals from the air above a leaf. From there, the researchers characterized the volatile organic compounds (VOCs) stuck to the fiber by inserting it directly into a gas chromatograph-mass spectrometer.

"Our approach is unique because we're testing the exact location where a canine sniffs the grape leaf," says Rangel. "So, we're analyzing the same airspace in both scenarios, whether we're in the chemistry lab or the canine lab."

So far, the team has optimized their process from the VOCs emitted from healthy leaves. Initial results from comparisons of healthy and fungus-impacted grapes revealed that the baseline odors emitted from healthy leaves include more acidic odor compounds than sick ones.

In fact, healthy leaves released fewer vapors over time, says Rangel, in contrast to sick leaves that expelled more VOCs as the infection grew.

Next, the researchers will analyze the chemical composition of what's wafting off the leaves at different stages of infection. Once they've identified a few key molecules, they will present each one individually to the canines, measure the animals' responses to each, and test the smallest amount needed for detection. Like how certain scents, such as vinegar, are strong in small amounts, the researchers think that dogs may pick up on certain VOCs more easily than others. Using those compounds for training could enable more sensitive and accurate mildew identification, especially early-stage infections.

"The ultimate goal is to move away from the visual diagnosis of mildew to odor diagnosis as the gold standard," says Prada-Tiedemann. "Even when we can't see it ourselves, the dog sitting next to a plant can tell you with their nose, 'uh oh, that vine's starting to go.'"

By "bridging the canine to chemistry," as Prada-Tiedemann says, the team wants to find a more efficient solution for protecting grapevines from a widespread and damaging disease. After all, she adds, "We all want good wine!"

Lihua Lou in the College of Engineering and Computing is investigating bioengineered heart tissue

Science & Technology
By David Drucker

September 21, 2023 at 11:00am

There are only so many ways to heal a broken heart, at least medically speaking. But thanks to new research, a promising treatment may be on the way.

Just ask FIU postdoctoral researcher Lihua Lou, who has been named the 2023 Early Career Stop Heart Disease Researcher of the Year by the Florida Heart Research Foundation. She is conducting research as part of an international team called CELL-MET to see how lab-made patches of tissue could repair damaged heart muscles.

CELL-MET is the National Science Foundation Engineering Research Center in Cellular Metamaterials, led by Boston University. FIU and the University of Michigan are major team members.

“It is my true honor to be recognized as this year’s Early Career Stop Heart Disease Researcher,” Lihua said. “I am incredibly proud to be a member of this research team conducting interdisciplinary research to find an innovative treatment for heart disease.”

One person dies every 33 seconds in the United States from cardiovascular disease, according to the Centers for Disease Control and Prevention. One of the main barriers to fighting heart disease is that damaged heart muscle tissue does not regenerate easily on its own. The CELL-MET team’s idea to overcome this obstacle is to replace damaged cells using a patch made of lab-made cardiac tissue which, when placed onto a damaged heart, could infuse healthy cells into an injured area.

Lou is specifically researching the patch’s ability to resist deformation under stress and its other mechanical and material characteristics. She works alongside FIU Distinguished University Professor Arvind Agarwal, a co-principal investigator of the team.

“I am incredibly proud to see Dr. Lou acknowledged by the Florida Heart Foundation,” Agarwal said. “This award is a testament to her outstanding work ethic, team-first mentality and exceptional research abilities.”

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Lou uses a micro-indentation system for soft and ultra-soft materials.

With the award, Lou looks to develop a ‘golden standard’ for the mechanical properties of bioengineered cardiac tissue – a reference guide when creating heart bandages in the future. She will also work to create specialized equipment for measuring this data for cardiac tissue and similar tissues.

“Dr. Lou's groundbreaking work and her unwavering dedication to addressing the challenges of heart disease positioned her as an exemplary candidate for our award,” said the Florida Heart Research Foundation’s Medical Advisory Committee in a joint statement. “Her contributions extend beyond her research endeavors. Dr. Lou’s active involvement in cross-institutional projects, including collaborations with various universities, showcases her commitment to collaborative scientific advancement.”

“Additionally, Dr. Lou's mentorship of aspiring researchers and her prolific publication record of 22 journal papers underline her dedication to fostering scientific growth.”

Prior to FIU, Lou obtained a Master’s degree in textiles science and engineering, where she researched nanomaterials. She later earned a Ph.D. in environmental science, where she studied toxicology and how materials interact with the human body. She connects the dots across disciplines in her research today.

Other institutions involved in the research at CELL-MET include Brown University, CNEA (Argentina), Columbia University, École Polytechnique Fédérale de Lausanne (Switzerland), Fort Valley State University, Harvard Medical School, National University of Ireland, NHS College, North Carolina State University, Queen’s University Belfast (Northern Ireland) and the Wyss Institute.