Our lab is broadly interested in insect immunity and learning what influences the ability of the immune system to successfully fight off infection.  We are interested in studying this from many perspectives - ecological, physiological and biochemical - and many projects span one or more of these perspectives. We are interested not only in factors that impact resistance – the ability to control pathogen load, but also factors that impact tolerance – the ability to withstand the damage and consequences at a given pathogen load. 

Below are general descriptions of the research we’re tackling, but visit our lab members page to see a list of current students doing research in the lab and a brief description of their projects! Our lab welcomes emails from any interested students or potential collaborators (moria.chambers@bucknell.edu)!

Investigating Bacterial Pathogenesis in Fruit Flies

Using Drosophila melanogaster as a model host, we are dissecting the interactions between host immunity, metabolism and behavior. This model system is very amenable to student research and our lab has many projects accessible to undergraduate and even high school researchers.  Drosophila are very easy to maintain and have many genetic tools easily available for order from stock centers.  We also have a suite of natural pathogens that enable study of naturally evolved bacterial-host interactions.  To learn more about using fruit flies as an infection model - watch our short JOVE video, which was authored by two of my student mentees while I was at Cornell!

Infections sustained for a lifetime are one of the most widespread categories of infections, yet these chronic infections are often neglected by researchers in favor of an emphasis on high mortality, transient acute infections. Humans can be chronically infected with a diverse array of parasites while exhibiting minimal clinical symptoms (e.g. Toxoplasma gondii, varicella zoster virus, Borrelia burgdorferi).  Chronic infections are sometimes associated with nutritive and behavioral disorders suggesting that these diseases have the potential to metabolically and behaviorally alter their host.

Using Drosophila melanogaster, we found that chronic infection causes flies to be better at fighting future infections and more susceptible to starvation stress (published in PLoS One 2019). My students at Bucknell, led by Frank Satriale (‘19) and Abby Wukitch (‘22), then found that this protection is due to a combination of improved tolerance and resistance, and this was published in Infection and Immunity (2023) with six Bucknell undergraduate co-authors. Our current work focuses of determining the impact of timing and genetics on this protective effect.

This work also serves as the foundation for the two course-based undergraduate research experiences (CUREs) that I’ve developed. I have first-year students in BIO202, a CURE required for all Biology majors, focusing on questions they can tackle using survival and bacterial load assays in the fly to let them design experiments on how various factors influence tolerance and resistance. Over the years, students have assessed the impact of genetic mutations that alter fat storage on response to infection and how this intersects with dietary affects. This fall, students will be tackling how a bacterial species isolated from wild-caught fireflies affects fruit flies!

In Biochemical Methods (BIO340/CHEM358), a course required for Cell Biology and Biochemistry majors, I have students isolate RNA from infected fruit flies, and use qRT-PCR to assess gene expression to help us learn more about response to infection.

Assessing Firefly Immunity

Although fireflies are among the most charismatic insect species, recent reports suggest that populations of some species are declining. Likely contributors to firefly declines include anthropogenic changes like climate change and light pollution, and changes to land use leading to habitat loss. In collaboration with Dr. Sarah Lower (Biology), we’re particularly interested in studying what factors influence fireflies ability to respond to infection and how immunity is regulated across life-span as fireflies spend up up to two years as larvae and only a few weeks as adults.

Very little was known about firefly immunity before we began working on it, but in our first summer we determined that Common Eastern fireflies, Photinus pyralis, were susceptible to two commonly used bacterial pathogens and surprisingly unaffected by high doses of two bacterial pathogens that are very virulent in other insect species. We also found that the initial body condition of the fireflies and when the fireflies are caught (adults are flying around PA from June-August) impacts their ability to survive infection. This resulted in our first publication on firefly immunity, published in Ecological Entomology in 2023 with three undergraduate co-authors: Madden Tuffy (‘21), Deeshani Patel (‘22), and Zhengkai Zhu (‘22) (spotlighted by the Bucknellian, NorthCentralPA.com & WITF The Spark) .

This has been a rapidly expanding avenue of inquiry for the lab with the work funded by the Pennsylvania Firefly Festival and the Pittsburgh Foundation. We have had at least three undergraduates a summer working on the projects for the past two years!

During that time we’ve assessed how body condition and seasonality impacts tolerance and resistance, assessed the impact of dietary sugar on survival and whether our results another local firefly, Photinus scintillans, is affected by similar factors. Student have presented this work at local symposia and at the Society for Integrated and Comparative Biology Conference and are currently drafting manuscripts to be submitted in the upcoming year.

Harnessing Insect Antimicrobial Peptides

While antibiotic resistant bacteria are increasing in number, the investment in antibiotics by pharmaceutical companies remains low due to the minimal financial incentive. There is a need for new antibiotics to help combat antibiotic resistance bacteria, and one potential source of novel antimicrobials are insects, which have large amounts of diversity that remains untapped! In collaboration with Prof. Sarah Smith (Chemistry), we are specifically interested in how insect antimicrobial peptide might be adapted for therapeutic use focusing on how small changes in the amino acid sequences impact both the structure and function of the peptides.

Student have presented this work at local symposia and at the American Society for Biochemistry and Molecular Biology Annual Meeting and are currently drafting our first manuscript for submission.