You can read more about this prestigious and competitive award here:
https://www.smartscholarship.org/smart/en?id=about_smart
Walking into Ben Parker’s lab, you are greeted by rows upon rows of small plants, each in their own enclosed container with a complex handwritten label. What initially looks like a greenhouse operation changes quickly when you look closely at the plants: each is covered by hundreds of tiny bugs, or pea aphids.
Parker’s lab utilizes the pea aphid as a model organism to study its life history traits and genetics and uses the findings to further understand larger questions in biology, evolutionary biology, and microbiology. The pea aphid system offers two main advantages: the insects give live birth to genetically identical offspring in just 10 days, and their bodies contain a simple microbial community, allowing Parker and his researchers to easily add or remove microbes in the systems and complete various mechanistic studies.
Bacteria are one microbe that inhabit aphids. They are vertically transmitted, which means they are passed from parents to offspring, and can form important symbiotic relationships with their hosts.
“The bacteria Regiella insectcola makes aphids resistant to the fungal pathogen Pandora neoaphidis,” Parker elaborates. “Not all aphids harbor Regiella, but those that do are more resistant to fungal infections.”
However, the bacteria are not entirely beneficial.
“One big question we are interested in is how the aphid’s immune system evolves to accommodate these beneficial bacteria in ways that still allow it to fight off bacterial pathogens,” Parker says.
For example, the lab has been focusing on the phenoloxidase mechanism, which is an enzyme aphids use in melanization (a method insects use to fight pathogenic microbes). Aphids harboring Regiella have reduced gene expression of the phenoloxidase enzyme producing genes.
The lab theorizes that this occurs because the bacteria are attempting to maximize their abundance, despite compromising the aphid’s ability to fight off other bacteria, but this finding is just a first glimpse into the mechanism.
“We want to understand that in a broader context,” Parker states. “We want to know what effects that has on interactions with pathogenic bacteria and how those mechanisms are evolving in natural populations.”
Viral genes are also vertically transmitted between aphid parents and their offspring. One such gene has interesting morphological effects on the host wherein in two genetically identical offspring, one can be winged while the other is wingless.
This occurrence is an example of a phenotypically plastic traits, or a morphological trait influenced by the environment. In this case, the environmental trait influencing gene expression is plant crowdedness, which aphids have evolved to sense. The viral gene triggers the production of winged offspring by making aphids more sensitive to crowding.
“When it is too crowded, they produce winged offspring, so they can fly to another plant and start over,” Parker explains.
Currently, the Parker lab is focusing their studies on the genome and microbiome of the Pandora neoaphidis fungal pathogen. Additionally, they are working to understand aphid immune systems and how different aphid genotypes interact with bacteria. This talented group undoubtedly has a promising future.
-By Taylor Mattioli
Hailing from Nepal, Bikash Bogati has traveled far to pursue his doctoral degree at the University of Tennessee. In Nepal, he obtained his undergraduate degree in medical microbiology and worked in a diagnostic microbiology lab. He now works with Elizabeth Fozo, associate professor of microbiology, studying how bacteria survive different stress conditions.
Specifically, he focuses on enterohemorrhagic E. coli, or EHEC, which is a food-borne pathogen. EHEC produces the Shiga toxin, which causes damage to the intestinal wall and severe illness in humans.
“I’m looking into a gene segment that codes for a type I toxin protein, called ZorO, to see how it helps the bacteria to survive in different stress conditions,” Bogati said.
Not much is known about this small protein or its specific function; however, when ZorO is artificially overproduced, cell growth stasis and death ensue.
“My dissertation work mostly focuses on what we overproduce as toxic [in the lab] might be helpful for the bacteria,” Bogati explains. “This protein can help the bacteria survive antibiotics that we have been testing in the lab.”
Understanding this system is important, as antibiotic resistance is a growing concern.
“It is really challenging to have antibiotics synthesized compared to how fast the bacteria are gaining resistance,” Bogati elaborates.
During his time at UT, Bogati has contributed to more than just the understanding of E. coli. In 2018, he was inspired to seek community service opportunities when he was asked, “what would you do if you had an extra hour in your day?”
“I said that I would do something for others, because whatever time I have, I’m using on myself,” he smiles. He now volunteers with Volunteer Assisted Transportation, which connects volunteer drivers to individuals in need of transportation.
The organization has had a large impact on Bogati’s view of America, and he has learned much from those he drives.
“As an international student, we are used to the school life, and we don’t have much interaction with people outside of school,” he laughs. “I started getting to know their lives. I now realize our lives are all pretty similar.”
His eyes shine as he talks about the veterans, teachers, and other passengers he has connected with. “We can learn so much from their lives and experiences.”
After he obtains his PhD, Bogati will continue to study infectious diseases and antibiotic resistance as a post-doctoral researcher at Emory University. He is eager to continue volunteering as well.
-By Taylor Mattioli
Chances are, many have heard of the fungal pathogen Candida albicans without realizing it. The pathogen causes many diseases, including yeast infections, which cause significant issues for women worldwide, and thrush, which is a mouth yeast infection that is common in babies and AIDS sufferers.
Andy Wagner, a doctoral researcher in Todd Reynolds’s lab, focuses his work on this pesky pathogen. Wagner explains that while yeast infections may be uncomfortable, they are generally mild and easily treated; however, Candida albicans can occasionally cause bloodstream infections. Although rare, these infections have a mortality rate of about 30-50 percent, and they can be especially problematic for people with compromised immune systems.
Wagner’s work specifically focuses on the idea that microbiologists can alter how the disease is recognized by the patient’s immune system to create a more favorable outcome for the patient. To make these alterations, Wagner focuses on Candida albicans’ cell wall, which is composed of three main layers: a basal layer composed of chitin, a middle layer composed of beta glucans, and an outer protein coat.
“The host’s immune system recognizes the beta glucans layer of this cell wall,” Wagner explains. “The outer protein coat serves as a barrier that prevents it from being recognized by the host immune system.”
Inducing the cell to expose its beta glucans layer is no easy task.
“There are signal transduction pathways that sense an outside change and will transmit the signal into the fungus to make it change its structural organization,” Wagner explains. “We found that if we can disrupt these signal transduction pathways, we can get the fungus to inappropriately expose the beta glucans layer.”
Essentially, by altering the signaling pathways, Wagner alters how the cell wall is made. Currently, he is seeing overproduction of the basal layer and underproduction of the outer protein layer.
“The basal layer is definitely being affected, which prevents the cell wall from being put together correctly,” Wager states. That, in turn, is making the recognizable basal layer more visible to the host’s immune receptors. This process is aptly termed “unmasking.”
Wagner’s results are promising. “If we infect mice with these mutant fungus cells, we find they are able to recognize and clear the infection and survive longer,” he smiles.
In the future, Wagner wants to continue working on disease-causing fungi, and he is hopeful that unmasking can be applied to other fungi as well.
For researchers looking to unravel the mysteries of Jupiter’s moon Europa, a resource has emerged as a potential key to unlocking if the moon is habitable — the Juneau Icefield.
The University of Tennessee is ranked seventh in the scientific front of ecology and environmental sciences for cyanobacterial bloom research, according to the sixth annual Research Fronts report, “Phosphorus loads and pollution and health risk of cyanobacterial bloom.”
The Research Fronts report identifies the hottest emerging specialty areas in scientific research. Fronts are formed when several highly cited papers are frequently cited together, showing a common theme of research. Identifying and tracking these fronts provide advantages for publishers, research administrators, policy makers, and others who support and advance the research field.
The amount of core research papers published from an institution determines ranking within a research field. UT published four core papers out of the total 38 included in the report.
Cyanobacterial blooms occur when large amounts of wastewater containing phosphorus and nitrogen enter a body of water from industrial, agricultural, or residential areas, turning the water blue or green from an increase in algae. Toxins released by the blooms can result in ecological fallout, endangering the health and safety of the water, aquatic plants, and animals.
Core papers in the field of cyanobacterial bloom research focused on four main aspects: the impact of nutrient loads on the blooms; diversity, growth, metabolism, genetics, and toxin production of different cyanobacteria species; health-risks associated with cyanobacteria toxins; and control strategies for controlling blooms in specific areas.
Steven Wilhelm, the Kenneth and Blair Mossman Professor of Microbiology, is a key researcher at UT for cyanobacterial blooms. Wilhelm’s lab uses biomolecular tools such as DNA and RNA sequencing, metabolomics, and others to study cyanobacteria, viruses, bacteria, and algae.