2025 Summer Research for Undergraduates (REU) in Aerobiome Research
Have you ever considered the air to be a place that is full of living microscopic organisms that is constantly changing?
Our team of researchers has, and we are working together to investigate a wide range of important and unanswered questions:
- What microbes are in the air?
- Where do they come from, and where do they go?
- What do they do while they are in the air?
If these sound like interesting questions to you, then consider joining our team of diverse scientists for a unique and exciting summer research program.
The BROADN REU program at Colorado State University is sponsored by the National Science Foundation (NSF) and offers undergraduates a mentored research experience to work with a diverse team of scientists to investigate how the microbiome of the air is altered by environmental stresses, and how it impacts human, animal, and environmental health. Our goal is to train undergraduate researchers in the interdisciplinary laboratories conducting research aligned with BROADN’s research goals.
We also strive to honor CSU’s commitment to diversity, equity, and inclusion.
BROADN will host a summer REU program at Colorado State University's Fort Collins Campus from May 27 - August 1, 2025.
Priority Application Deadline: Friday, February 7, 2025 by 11:59 PM MST.
Eligibility Criteria
Students who will graduate at the end of spring semester 2025 are not eligible for this program.
Participants must be either U.S. citizens or permanent residents of the U.S. or its possessions (NSF requirement).
During the application process, you will be asked to submit unofficial course transcripts and provide email contact information for one person who can write a letter of recommendation for you. Letters of recommendation must be submitted by the application deadline. For assistance or questions regarding letters of recommendation, please see here.
Potetial Summer Research Projects
Please reference at least two of the below projects* that are of interest to you during the application process. Click on the project titles for more information.
*We will do our best to match students with their desired choice based on preference and availability, but please note that projects are subject to change.
Participants will:
- Conduct original scientific research on a project in a BROADN advisor’s research group.
- Participate in a cohort of undergraduate students working on interrelated projects in parallel.
- Develop professional skills for communicating science (elevator speeches, formal presentations, science communication in popular media).
- Discuss resources for professional pathways in STEM careers.
Participants will receive:
- A stipend of $600/week for 10 weeks ($6,000 total). These funds are considered a scholarship/fellowship and may be taxable. NOTE: If you receive financial aid, please check with your Office of Financial Aid prior to accepting the stipend, regarding any potential impacts to your financial aid package.
- Room and board (includes on-campus housing and a meal plan).
- Roundtrip travel coverage to and from the CSU Fort Collins campus.
For more information or questions about the application process, please contact: [email protected], BROADN REU program director.
Potential Summer Research Projects
Project 1: Characterizing Spore Emissions of Cronartium ribicola
Lead Investigators: Angela Bosco-Lauth; Jeffery Marano Jane Stewart; Mark Hernandez
Abstract: While plant pathogens often spread via airborne dispersion, detecting the pathogenic fractions within the greater aerobiome is difficult using conventional aerosol samplers. To investigate this, we will utilize a small growth chamber (10 ft3) to characterize spore emissions profiles (AKA: “source strength”) of Ribes plants infected with Cronartium ribicola urediniospores (causative agent of white pine blister rust) under controlled conditions (temperature, humidity and light) in a limited aerosol volume. Infected Ribes plants will be placed in these chambers with settling plates at various levels (below, adjacent, above) the plants.
A low volume condensation sampler (VIVAS Biospot) and a high-volume sampler (SASS) will be co-located with the plants in the chamber to determine aerosol load and to compare sampler efficiency as determined by total DNA and qPCR. Sampling will be performed in triplicate and the entire process repeated using infected white pine samplings, which host a different life-stage (aeciospores) of C. ribicola. The information gained by these experiments will provide a baseline for sampler detection efficiency at multiple life stages of C. ribicola using pathogen DNA recovery and will inform the spore emission patterns of infected plants. This work will inform future experiments designed to capture spore emissions in a larger greenhouse setting.
Project 2: Gene discovery: How do microbes survive in the aerobiome?
Lead Investigators: Jan Leach; Brad Borlee
Abstract: Bacillus are bacteria that have been routinely isolated from the air in sampling performed as part of BROADN. The goal of these projects will be to discover variants of Bacillus that have lost functions predicted to be important for survival of the microbes in the air. In these laboratory-based projects, the students will screen for one or two survival traits that might include resistance to antibiotics, attachment, biofilm/surfactant production, desiccation tolerance, and/or pigment production. A library of Bacillus strains (called an mGWAS population) will be screened using established techniques to identify variants that lack the survival trait.
The students will learn microbiological techniques (media preparation, bacterial culture manipulation, and library screening protocols) as well as data analysis and presentation skills. Each student will participate and present in a laboratory meeting, where they will receive feedback from graduate students and post docs. Depending on how quickly the variant strains are identified, the students could participate in the computational analysis (a genome-wide association analysis) to identify the genes that account for the trait variation. The projects will be directly supervised by a collaborative team of BROADN PIs (Leach and Borlee).
Project 3: Unmasking Aerobiome Superpowers: Genetic Dissection of Microbial Survival Traits
Lead Investigator: Brad Borlee
The Borlee laboratory is focused on developing tools, resources, and assays to test mechanistic models of how bacteria sense and respond to environmental stress. The aerobiome is an untapped reservoir for understanding the physiology of microbes with respect to the organism’s response and adaptation to the extreme environment that bacteria encounter when transiting through the air. In our efforts to better understand the behavior of organisms that survive in the atmosphere, we have isolated bacteria that can survive the stressors of flying through the air.
These bacteria possess superpowers that allow them to kill fungi, nucleate the formation of ice, and produce pigments that may potentially protect them from UV damage. This project will involve the construction and screening of a library of transposon insertion mutants to identify the genes that contribute to the superpowers that aerobiome isolates employ to survive in the atmosphere and colonization of the new environments that they are deposited into. Students will learn how to make a transposon library of bacterial mutants and screen the library for mutants that no longer nucleate the formation of ice, produce pigments, survive desiccation, and inhibit fungal growth.
Project 4: Innovative Bioaerosol Sampling and Analysis: Developing and Evaluating a High-Efficiency Virtual Impactor for Environmental and Health Applications
Lead Investigators: Shantanu Jathar; Marina Nieto-Caballero
At the Laboratory of Air Quality Research (LAQR), we study the emissions, transformations, properties, and impacts of atmospheric aerosols. Aerosols of natural and anthropogenic origin (which include bioaerosols) have outsized impacts on air quality, climate, human health and ecosystems. LAQR aims to develop an innovative virtual impactor (or concentrator) designed to capture bioaerosols efficiently, thus optimizing the collection of airborne biological particles in a liquid medium. This advancement is particularly important for applications in environmental monitoring, public health, and biodefense, where reliable bioaerosol sampling and detection are crucial. As part of this project, the REU intern will play a key role in the analysis of bioaerosols collected during laboratory and field experiments.
The intern will utilize a range of techniques to detect, identify, and quantify bioaerosols in collected samples. These methods include: Optical Microscopy: for initial visualization and morphological assessment. Quantitative Polymerase Chain Reaction (qPCR): to accurately quantify specific microbial populations. Omics Approaches: for in-depth molecular analysis and identification of diverse microbial communities. Culturing Techniques: to isolate and grow viable bioaerosol species for further characterization. REU students will collaborate with a graduate student leading the instrument’s development and optimization. This partnership will involve learning about the principles of virtual impactors, contributing to performance characterization studies, and assisting in troubleshooting and refining the instrument to ensure optimal bioaerosol capture efficiency.
The intern will also be involved in both controlled laboratory experiments and real-world field applications, gathering data that will contribute to a comprehensive understanding of the virtual impactor’s performance across various environments. This position will offer a hands-on experience in both analytical laboratory techniques and applied environmental science instrumentation. The intern will gain insight into interdisciplinary research combining microbiology, analytical chemistry, and engineering principles, contributing to impactful advancements in bioaerosol research and technology.
Project 5: Fungal Resilience: Unraveling Survival Mechanisms of Fungi Under Atmospheric Stress
Lead Investigator: Jane Stewart
The Stewart lab primarily studies the ecology, biology and genetics of forest pathogens. In relation to BROADN, we are characterizing fungal pathogen survivability under harsh atmospheric conditions. In the air, lofted airborne spores are exposed to rapid dehydration and some fungi lose viability within a few hours whereas in other species, like ectomycorrhizal basidiomycetes, spore can survive for at least 4 years under various storage conditions. Other studies that have suggested the mechanism for resistance to dehydration may be the ability to fold and then rehydrate or that trehalose accumulation, a nonreducing disaccharide of glucose, plays a role in protection to environmental stressors by protecting proteins and cellular membranes from inactivation or denaturation. There is a need to further characterize these adaptations across a broad range of fungi found within the aerobiome in natural environments.
Project 6: Ice Nucleation Dynamics in the Aerobiome: Analyzing INP Spectra Under Diverse Atmospheric Conditions
Lead Investigators: Sonia Kreidenweis; Brad Borlee
In this project, the REU student will work with data and samples from the 2023 springtime campaigns at the Central Plains Experiment Range (CPER) NEON site, analyzing the spectra of ice nucleating particles (INPs) on selected days across the entire campaign. We will focus on filters from days and nights that were impacted by different wind directions and meteorological conditions, such as very dry, overnight rainy, and stormy, to look at how upwind conditions may have affected the INPs. The project can be largely computational for those mostly interested in the data analysis aspect, but an interested student can also train on the CSU ice spectrometer to learn how to obtain the INP spectra and possibly also obtain and analyze samples in summer 2025.
Project 7: Investigating DNA Stability and Microbial Survival: Evaluating Filter Storage Conditions for Bioaerosol Samples
Lead Investigators: Sonia Kreidenweis; Mark Hernandez; Marina Nieto-Caballero
This project involves investigation of DNA losses from filters that have not been held frozen after sampling or treated in other ways designed to minimize the degradation of DNA. We are exploring whether we can identify which types of bacteria and fungi might survive under different filter storage options and time periods, especially comparing freezing of samples to holding them at room temperature. For this project, sampling using IMPROVE coarse mass sampling protocols will be conducted, for known mixtures of microbes generated into an environmental chamber and also for outdoor samples. Filters will then be split into different fractions that will be stored according to several different protocols (e.g., frozen, at room temperature, at room temperature but with desiccant). Total DNA will be quantified immediately after sampling and then after 1 day, 1 week, and 1 month of storage to evaluate stability.