By Shannon Garrick '17
Ever wonder what bacteria you have in your belly button? Although it may sound odd, learning what microbes reside in that cavernous space may tell to you a lot about your personal microbiome, and maybe your innate health.
The microbiome is a major topic in popular science, with articles daily on how we exchange microbial clouds with one another, the effects of antibiotic use and our diet on our gut microbiota, and even the medical benefit of coating newborns in the microbiome of their mothers. The microbiome is important because we are learning about the huge role diverse bacterial species play in many physiological processes, including immunity (having certain bacteria that can help protect you from developing allergies and asthma) and digestion (not having the right flora can cause problems).
So why is our belly button bacteria specifically interesting and important? Dr. Carmony Hartwig, Assistant Professor of Biology, challenged her Spring 2016 Microbiology and Immunology class, as well as the two previous Microbiology and Immunology classes, to investigate this question by swabbing their belly buttons and culturing whatever microbes happen to reside there. Using aseptic technique and bacterial culturing each student had the opportunity to visually and genetically identify one select species of their microbial residents in order to learn more about the morphology, biochemical metabolism and commonality of the species that we all share on our skin. This multi-week laboratory exercise substitutes the common 'unknown' identification laboratory with a true unknown - one that lives on each student! In addition to solving this mystery, students gained a hands-on experience with several common microbiology and biotechnology skills such as aseptic technique, microbial culturing, conducting biochemical tests, DNA extraction, and PCR and sequencing of specific bacterial genes as they attempted to identify their 'unknown' microbe.
But the quest for delimiting our navel microbes didn't stop there. Starting in September 2015, Nadine Brockmann and Virginia Merida, both seniors, began doing independent research with Hartwig on belly button bacteria in both athlete and non-athlete Catawba College student populations. Nadine, who took Microbiology and Immunology in the fall of 2014, and Virginia, who was currently enrolled in the 2016 course, were interested in expanding the class project to explore the potential differences in these distinct populations in an effort to understand the connection with microbial skin content with overall human health. The athletic groups tested included random sampling of aquatic and non-aquatic sports, in order to additionally investigate the environmental influence on microbial composition in the athletic populations.
They obtained consent from both athlete and non-athlete populations, took swabs from over 40 student belly buttons, cultured the bacteria, looked at the total species morphology, species richness and abundance, completed DNA extractions, amplified the 16S ribosomal gene using PCR and sent their PCR products out for sequence analysis. After the gene sequences came back, they used bioinformatics (The Sequence Manipulation Suite, NCBI BLAST and GenBank) to identify what species of bacteria comprised each individual's belly button.
Results from this study showed few differences in the bacterial species abundance between non-athletes and athletes (aquatic and non-aquatic), but there were differences in the overall species composition of bacterial communities. Aquatic athletes had very little to no Staphylococcus when compared to non-aquatic, indoor and outdoor athletes. Aquatic athletes also had higher numbers of Cornyebacterium compared to the non-aquatic athletes. Overall, these findings suggest that although regular exercise does not significantly alter the abundance or richness of our navel microbiota, our environment can affect the species composition of our most well-protected body parts. How this relates to overall human health or the ability of common skin microbes to prevent colonization by disease-causing bacteria requires further exploration.
Both Nadine and Virginia presented at the State of North Carolina Undergraduate Research and Creativity Symposium (SNCURCS; Fall 2015), at the Regional Association of Southeastern Biologist (ASB) conference on April 1st, 2016, and at Catawba's Research and Creativity Symposium (CRCS) on April 14th, 2016. Hartwig plans on continuing this exercise in future courses and with interested research students.