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Germs on My Phone?! Engage Biology Nonmajors with This (Gross) Lab

To personalize her labs, Beatrice Fineschi, PhD, has students collect bacteria from their phones and chairs, then use high-tech methods to ID it.

Educator

Beatrice Fineschi, PhD

Associate Instructional Professor of Biological Sciences, University of Chicago

PhDin Biology, MS in Biology, BS in Biology

What is life? How does it work and evolve? These are two fundamental questions at the heart of the Core Biology course taught by Beatrice Fineschi, PhD, an associate instructor at the College of the University of Chicago. Though biology is a relevant topic for all students—given that they are biological organisms who encounter other biological organisms every day—Fineschi found that undergraduates who are not science majors do not always see it that way. In fact, she has noticed an increase in the number of distractions and a decrease in their engagement over the course of her teaching career.

To address this, Fineschi has pulled from both low-tech (traditional) and high-tech approaches to create an approach that is as attention-grabbing on day one as it is during finals week. One excellent example is her makeover of the typical bacteria identification lab that is a staple of introductory biology courses.

Though this is often taught using virtual labs or professionally prepared slides, Fineschi has found a way to make the most of today’s technology to provide a personalized, hands-on lab that students love.

Below, she shares her steps, beginning with the skin-crawling question that sets everything in motion.

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Context

“I love teaching students in the lab, since we have such cutting-edge technology that allows me to provide a sophisticated experience. But I also relate what we are doing to their lives. They get to see and touch and do things, which I believe they need to do to appreciate the topic.”

— Beatrice Fineschi, PhD

Course: BIOS 10130 Core Biology

Course description: What is life? How does it work and evolve? This course uses student-centered interactive learning in the lab, assigned readings from both the popular press and primary scientific literature, and directed writing exercises to explore the nature and functions of living organisms, their interactions with each other, and their environment.

Fineschi’s ideas for adding excitement to bacteria ID labs

Fineschi starts the semester not with a dry syllabus read but with a juicy sales pitch. “Do you think there are bacteria here—on our bodies, on our chairs, on our phones?” she asks the class. Students usually look at their devices and laugh—or cringe. Then comes the pitch: “What if I told you that there are millions of bacteria all around us, and that in a few weeks, you will tell me at least one type of bacteria that is in this room?”

Once she has their attention, she follows up with the most exciting bullet points she can think of: They will be doing DNA analysis using high-tech equipment, and they will be doing it all themselves, with minimal teacher guidance. (They also tackle evolutionary biology and antibiotic resistance, which are familiar and interesting to most college students, regardless of their major.)

Make sure they have the background to do the work

This step is the practical nuts and bolts of how labs work, and it occurs during the second week. As soon as students enter the lab, Fineschi shares a PowerPoint presentation that demonstrates the tools that they will be using, including test tubes, pipettes, Petri dishes, and reagents. “If I don’t do this, students get lost when they actually have to start their experiments,” she says. “It’s just not practical to explain the different elements as students are starting to work.”

Have students pick the items they want to test for bacteria

Also in the second week, Fineschi asks students to take samples of bacteria in the classroom environment. Sources can include the floor, their phone, a door handle, their skin, and their clothes, for example. Each student gets one sterile cotton swab and one Petri dish so they each can isolate and identify one specific bacterium. She reminds the students (repeatedly) to thoroughly and clearly label their samples with their own name and the specific location they swabbed. (She then collects the dishes and puts them in the lab’s incubator for 24 hours before moving them into the lab’s refrigerator, where they will remain until the next lab period.)

Ask for students’ observations of “their” bacteria

When Fineschi hands the samples back to the students in Week 3, she has them observe what has happened, write descriptions of what they see, and take photos to record the results. The students get excited about this part because they are so personally connected to their sample, says Fineschi. They say things like, “Look what was growing on my phone!”

Students will see different kinds of colonies of bacteria growing in their Petri dishes. Depending on the source of their sample, they will see colonies that differ in size, shape, color, and sheen. Students will take pictures with their phone, write a description, and share the results with the rest of the class.

Teach students the finer points of DNA extraction and identification

Students then choose a single colony for further analysis. This will be the colony that they will identify. The first step is to extract the DNA from the chosen bacteria and amplify a specific section of the bacterial genome DNA, a portion of the 16S gene. This gene is the gold standard for bacterial taxonomic identification.

In Week 4, students analyze their results by comparing their sequence to other sequences in the National Center for Biotechnoloy Information (NCBI)’s GenBank, an annotated database of all publicly available DNA sequences. They use BLAST, a sequence alignment tool also available through NCBI, to find the sequences that best match their own. Because these are real data, the result may not be picture-perfect, and they will often find more than one match. Students make a hypothesis about which of the matches is most likely to correspond to the species that they isolated by doing their own research on the biology and distribution of the candidate bacteria.

This laboratory exercise culminates with students writing their results on the board and discussing their reasoning with the rest of the class.

A final thought: Use homework to encourage reflection and learning

Since students need to remember what they did in each lab to connect the various topics they learn about, Fineschi assigns homework that students must complete between lab sessions.

“I found that if I didn’t do this, students would come each week and not remember what they did before, why it matters, and how it’s connected to what they are doing next,” she says. These assignments can be very simple—e.g., writing a paragraph about a topic such as, “Why did we extract the bacteria last week?”

Outcomes

Fineschi feels that her lab lesson works as intended. “The outcome is reality, it’s not from a kit,” she says. “This is the students’ personal experience, and what they learn—in addition to the biology topics we cover in the course—is that scientific results vary and are very complex.”

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