School of Biological Sciences

This story by Jennifer Woodruff is shared jointly with the University of Colorado Denver.

In response to rising global temperatures, many plants and animals are moving to higher elevations to survive in cooler temperatures. But a new study from the University of Colorado Denver (CU Denver) and Georgia Tech finds that for flying insects — including bees and moths — this escape route may have insurmountable issues that could mean their doom.

The research team examined more than 800 species of insects from around the world and discovered that many winged insects are moving to higher elevations much slower than their non-flying counterparts. This is because the thinner air at higher elevations provides less oxygen for species to use. Because flight requires more oxygen to generate energy for movement than other styles of movement, such as walking, these species are migrating more slowly.

The team’s findings were published in this week’s Nature Climate Change journal. Jesse Shaich, postbaccalaureate student at CU Denver, is also a member of the research team.

“When we think about where species will be able to live under climate change in the coming decades, we need to remember that animals are sensitive to more than just how hot or cold they are,” said CU Denver Assistant Professor of Integrated Biology Michael Moore, who led the study.

Declining insect biodiversity has direct impact on humans

If flying insects’ native habitats get too warm too quickly, and they can’t find a suitable alternative or adapt in time, that will likely lead to their extinction. Beyond just being bad for the bugs themselves, loss of insects is bad news for humans as well. Most crop pollinators are the flying species the researchers expect to be vulnerable, and their extinction would be catastrophic to global food supply. Not only would this have implications for agriculture and food supply chains, but similar challenges are likely true for other species that need a lot of oxygen to live.

“Our earth’s biodiversity is rapidly declining, especially amongst insects. The global loss of insects will be ecologically catastrophic, so we urgently need to understand why and how this is happening,” said James Stroud, assistant professor of Biological Sciences at Georgia Tech.

Broadening research on high elevation challenges

To conserve as many species as possible, researchers need to grasp the full scope of challenges plants and animals face, whether they can overcome these challenges, and to predict the locations where they can survive. High elevation environments are also difficult for new species because of the scarcity of food, stronger winds, more extreme cold snaps, and increased ultraviolet radiation.

Moore concludes, “If we want to design effective conservation strategies, we must consider a broader range of environmental factors that species need to live.”

About Georgia Institute of Technology
The Georgia Institute of Technology, or Georgia Tech, is one of the top public research universities in the U.S., developing leaders who advance technology and improve the human condition. The Institute offers business, computing, design, engineering, liberal arts, and sciences degrees. Its more than 45,000 undergraduate and graduate students, representing 50 states and more than 148 countries, study at the main campus in Atlanta, at campuses in France and China, and through distance and online learning. As a leading technological university, Georgia Tech is an engine of economic development for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society.

About the University of Colorado Denver
The University of Colorado Denver is the state’s premier public urban research university and equity-serving institution. Globally connected and locally invested, CU Denver partners with future-focused learners and communities to design accessible, relevant, and transformative educational experiences for every stage of life and career. Across seven schools and colleges in the heart of downtown Denver, our leading faculty inspires and works alongside students to solve complex challenges through boundary-breaking innovation, impactful research, and creative work. As part of the state’s largest university system, CU Denver is a major contributor to the Colorado economy, with 2,000 employees and an annual economic impact of $800 million. For more information, visit ucdenver.edu.

https://doi.org/10.1038/s41558-023-01794-2

Acknowledgments: Support was generously provided by the University of Colorado Denver (to M.P.M. and J.S.) and Washington University in St. Louis and the Georgia Institute of Technology (to J.T.S.). Conversations with J. de Mayo, J. Grady and A. Lenard and input from three reviewers improved this study.

Synthetic pesticides were first developed in the 1930s, but began to be widely used in agriculture in the 1950s and 1960s. Scientists have since discovered how toxic certain chemicals like DDT can be to ecologies and humans, but researchers still want to know more about their environmental impact on animal pollinators like bees, wasps, flies, butterflies, moths, beetles, and bats at the genetic level.

A School of Biological Sciences postdoctoral scholar will have a chance to help the U.S. Department of Agriculture (USDA) fill in the blanks in that knowledge, thanks to a two-year fellowship from the agency’s National Institute of Food and Agriculture (NIFA).

Sarah Orr, who researches in Professor Michael Goodisman’s lab, receives the grant for her project proposal, “Effects of Pesticide Exposure on Developmental Genetics in Bumblebees.” The award is part of a new USDA/NIFA $11.6 million funding initiative for projects that promote healthy populations of animal pollinators in agricultural systems where reliance of crops on pollinators is increasing, but pollinator numbers are declining.

“I am honored and ecstatic to have received this prestigious postdoctoral fellowship from USDA,” Orr says. “It’s rewarding to see how my research can have important implications in agriculture broadly in the U.S. Being able to bring in my own funding and serve as the project director on a grant as a postdoc has also been exciting. It’s a brief glimpse into what it will be like to hopefully be a faculty member myself in the future.”

Orr knows that pesticides play an important role in agricultural production and human food supply. Her scientific goal is to help find a balance between the risks and benefits of pesticide use.

“My investigation into the genetic effects of pesticides is unique and somewhat novel,” she says. “Beyond traditional toxicological methods, my project will improve our understanding of how pesticides may affect the developmental genetics of bumblebees.”

Homing in on key pollinators

Bumblebees are social insects native to North America and important pollinators for food crops including tomatoes, blueberries, and eggplant. As with most social insects, bumblebees live in colonies made up of a single queen and hundreds of sterile workers. “This genetic structure provides a really interesting model to study integrated development,” Orr says.

Orr’s project will investigate how pesticides affect the integrated developmental processes of Bombus impatiens bumblebees by examining changes in gene expression. Orr’s research will attempt to determine if pesticides impact the ratio of males to females in bee colonies, and how pesticides affect morphological traits of both worker and queen bees.

Orr says that new chemicals are approved before science can fully explore all of the potential environmental impact from their use. “For example, a lot of my research will focus on sulfoxaflor, a relatively new pesticide on the market,” she says, “and scientists are continuing to discover negative consequences of sulfoxaflor on native bee populations.”

USDA/NIFA New Contract/Grant/Agreement No. 2023-67012-39886, Proposal No. 2022-09642, Effects of Pesticide Exposure on Developmental Genetics in Bumblebees
Initial Award Year: 2023
Investigator: S.E. Orr

Researchers at the Georgia Institute of Technology (Georgia Tech) have received funding to study the concept of using modified strains of probiotic bacteria – that are already part of the human gut microbiome – to stimulate the formation of antibodies against the flu virus in the body’s mucosal membranes. Respiratory viruses like influenza infect the body through mucosal membranes, and the proof-of-concept project will help evaluate whether snippets of influenza proteins – tiny fragments of the virus – could be added to two common bacterial strains to create the antibody response. Antibodies in the mucosal membranes might then complement those created by traditional intramuscular injections to head off flu infection.

The research, supported by the Air Force Research Laboratory (AFRL), will study whether or not the harmless bacteria can be successfully modified to carry snippets of a viral coat protein that could stimulate the desired response in mucosal membranes lining the gut. Beyond reducing influenza infection in the general population, improved protection against the flu could have a significant impact on the U.S. military, which wants to provide the best possible protection for its warfighters to reduce possible impacts on readiness and training from influenza outbreaks.

At Georgia Tech, the project is a collaboration between researchers at the Georgia Tech Research Institute (GTRI) and the Georgia Tech School of Biological Sciences. All of the research at Georgia Tech will be done using BSL-2 facilities designed for this type of study. The award does not include research on animals or humans.

“Ultimately, this could one day make vaccination programs much more effective,” said Michael Farrell, a GTRI principal research scientist. “This isn’t going to be a replacement for flu vaccines as they currently exist, but it could act as an adjuvant – something that’s done in addition to vaccination to increase the overall immune response. To benefit from it, you might take a pill like you do with probiotics now.”

Using Common Probiotic Bacteria as Vehicles

The project will focus on two common probiotic bacteria: Escherichia coli – a gram-negative bacterium better known as E. coli – and Lactococcus lactis, a gram-positive bacterium found in cheese, buttermilk, and other dairy food items. The researchers will attempt to coax the bacteria to express the influenza virus’ Hemagglutinin (HA) receptor protein on their outer cell surface. There, the protein would stimulate an antibody response in the gut mucosal membrane as it passes through the body’s gastrointestinal tract.

“We’re using some well-established probiotic bacteria that have been utilized for dozens of years, are well vetted and safe for humans,” said Brian Hammer, an associate professor in the School of Biological Sciences who specializes in bacterial genetics. “Ultimately, the idea is to use these bacteria as a chassis to create living vaccines, since the body already tolerates them both well.”

Researchers at AFRL and Georgia Tech envision that a single pill or capsule would carry the bacteria into the gastrointestinal tract to provide the necessary antibody stimulation. The bacteria would be modified so they could not reproduce, preventing them from becoming part of the body’s gut microbiome – a diverse collection of bacteria that live in the body and help carry out specific functions, including metabolizing food and modulating the immune system.

“We know the human microbiome is intimately involved in human health and disease, influencing processes in ways that have both positive and negative outcomes for us,” said Richard Agans, senior research biological scientist at the U.S. Air Force School of Aerospace Medicine (USAFSAM). “Recently, we have started to better understand how the microbiome communicates with our bodies and how we can identify, target, and promote the beneficial aspects. Currently, we are working to determine how to utilize these microbial communities to better protect our warfighters as well as the general public.”

Overcoming Challenges of Manipulating Bacteria

Hammer’s lab specializes in manipulating proteins of organisms such as bacteria and viruses to create novel fusions. Among the techniques available is the new CRISPR-Cas, the gene-editing technology that was the subject of a Nobel Prize in 2020, but other more traditional techniques may also be used to get the influenza surface protein where the researchers want it to be.

Among the challenges ahead is that adding a new component to bacterial organisms can be difficult.

“In general, bacteria have evolved with the genetic components they need to survive,” Farrell explained. “If you add something else, they may just kick it out. It’s very hard to find a neutral location in the bacterial genome where we can stably add new functionality. This is especially true for this effort, in which there will be no cointroduction of antimicrobial resistance markers.”

In addition, the probiotic bacteria strains that are widely used in research as model organisms, or “lab rats,” are adapted to living in laboratory conditions. This project, however, will use natural commensal strains that co-exist in humans. That approach may make it even more challenging to add the appropriate material for expressing the viral proteins on the bacteria cell surfaces, Hammer said.

“We used to perceive that genes could be shuffled around in the bacteria without much effect on them, but we’re learning now that location really matters,” he said. “One of the concerns is that tools that work on the ‘lab rat’ versions of these bacteria will not be as readily accepted by these commensals.”

As part of the project, the researchers will have to show that the addition of the protein doesn’t cause instability in the bacteria, and that the modified bacteria generate the correct response when exposed to human immune cells in culture.

Proof of Concept Could Lead to Broader Vaccine Therapies

Beyond its importance to the military, influenza was chosen to study this adjuvant approach because a number of vaccines exist for this virus, and they have been well studied over the years. If this approach works with influenza, the combination of pill and injection might be useful for vaccines against other respiratory viruses.

“If this is ultimately successful, it could be the first foray into showing that these vehicles, these probiotics, could potentially be scaled up for lots of different therapeutic uses,” said Hammer. “By customizing the cargo, this approach could be rapidly adapted to address new and emerging threats that may arise in the future.”

Project Provides Student Opportunity

The two-year project life was chosen because of the expected difficulty – and because another of its goals is to train a master’s degree student in the bacterial modification techniques being utilized.

The Georgia Tech researchers have chosen an underrepresented minority student who holds an undergraduate degree in biology from Kennesaw State University and has worked in a commercial DNA laboratory. Katrina Lancaster will begin work on this project during fall semester, collaborating with both Hammer and Farrell – and the students and other researchers in their labs.

“This student will have excellent opportunities, not only to learn the skills in the lab and take the coursework, but also to develop a rich network of connections, both in the School of Biological Sciences and at GTRI, that will be helpful in moving forward and advancing their career,” Hammer said. “It’s a really beautiful combination of components for this project.”

The project is funded through the AFRL’s Minority Leaders Research Collaboration Program (ML-RCP).

“Partnering with academic institutions, such as GTRI, presents great opportunities for our team to interact and work with top minds in these fields to develop better outcomes for everyone,” Agans said. “We are especially grateful for the opportunity to mentor and provide opportunities for underrepresented students with STEM aspirations. We are excited to work with GTRI in this endeavor and envision this being just the first step.”

USAFSAM is part of the Air Force Research Laboratory’s 711th Human Performance Wing.

Writer: John Toon (john.toon@gtri.gatech.edu)
GTRI Communications
Georgia Tech Research Institute
Atlanta, Georgia

This story first appeared in the GTRI newsroom.