The Effect of Different Light Wavelengths on the Dust Microbiome

Presenter: Andy Siemens

Mentors: Jessica Green and Erica Hartmann, Biology

Poster: 59

Major: Biology 

Different light treatments affect the growth of certain bacterial strains in the built environment, however little is known about the effect of light on an entire bacterial community. The goal of this study is to investigate the impact of UV vs. visible light on the viability of the dust microbiome. We developed a method to quantify viable dust by treating samples with the DNA-binding agent propidium monoazide (PMA), which prevents the amplification of DNA from non-viable cells during polymerase chain reaction (PCR). This technique was used to determine the amount of DNA from live vs. dead cells by comparing amplified 16S gene copy numbers with and without PMA treatment using quantitative PCR (qPCR). As a pilot study, dust samples were treated with broad-spectrum light to determine the appropriate dosage for killing dust microbes. The built environment was simulated using light boxes designed by the Energy Studies in Buildings Laboratory. Experiments were performed in triplicate using identical box setups for each trial. In future experiments, the relationship between different wavelengths of light and bacterial viability will be tested by subjecting dust samples to sunlight with UV wavelengths removed, sunlight with visible and infrared wavelengths removed, and dark conditions. The results from these studies will influence the choice of light filtering in windows for buildings such as hospitals where the elimination of pathogens is extremely important.

Dust Microbial Communities Have Dosage-Dependent Responses to Daylight

Presenter: Andrew Siemens

Faculty Mentor: Jessica Green, Erica Hartmann

Presentation Type: Oral

Primary Research Area: Science

Major: Biology

Funding Source: UO UnderGrEBES Research Grant, University of Oregon Institute of Ecology and Evolution, $500; UO Undergraduate Research Opportunity Grant, UO Undergraduate Research Opportunity Program, $1000

Different light treatments affect the growth of certain bacterial strains in the built environment, however little is known about the effect of light on an entire bacterial community. The goal of this study is to investigate the impact of daylighting, specifically UV vs. visible light, on the viability of the dust microbiome. We collected dust samples and treated them with varying doses of broad-spectrum light. Using a method we developed to quantify the viability of microbes in dust, we determined the amount of DNA from live vs. dead cells by comparing 16S ribosomal gene copy numbers in each sample. The results from broad-spectrum light exposure revealed a decrease in dust viability as the amount of total light exposure increases. Subsequently, the relationship between different wavelengths of light and bacterial viability was tested by subjecting dust samples to sunlight with UV wavelengths removed, sunlight with visible and infrared wavelengths removed, and dark conditions. We achieved a gradient of lighting conditions that will help us determine whether the effect of daylighting on viability is impacted by UV light as compared to visible light. The results from this research could influence the choice of light filtering in windows for buildings such as hospitals where the elimination of pathogens is extremely important.