My qualification to teach Microbiology at the College comes from my degree in Immunology & Molecular Pathogenesis that came from a Department of Microbiology. There I took graduate courses in Virology, Biochemistry, Eukaryotic & Prokaryotic Cell Biology and of course, Immunology. Last week I was telling my department chair that when I first started teaching Microbiology I didn’t actually *feel* qualified to teach it. He didn’t understand, so I explained that while I had the required coursework, my experience was mostly in Virology and Eukaryotic Cell Biology – that was (and still is) my intellectual comfort zone. Microbiology courses tend to be focused more on Bacteriology.
He screwed his eyebrows up a bit. To him, viruses are “microbiology” every bit as much as bacteria. I laughed and explained that in the research world, there are two separate cultures: microbiologists and virologists. Microbiologists work on bacterial cells. Because viruses require eukaryotic cells* to make more of themselves virologists work on viruses and eukaryotic cells. Every department I ever worked in (4 different ones at 3 different institutions) had this divide. Maybe not necessarily a divide, but it was a self-segregation thing – the bacterial labs tended to cluster together, tended to have their own separate journal club meetings. At one level this makes sense as bacterial cells and eukaryotic cells are very different, the techniques used to study them are very different, the informal nomenclature for genes is different so a virologist listening to a presentation on the cell biology of bacteria in a room full of microbiologists is going to be swimming in a sea of jargon. The immune system reacts to both and in my experience immunology labs bridged the gap and ensured that any given departmental audience would have a more balanced expertise.
Anyhow, to my department chair “Microbiology” is one box and he is unable to mentally organize the contents of that box. Well he is fully capable, but to him the differences between the components of the box are abstract. He shared with me a similar phenomena in Chemistry (his background), rattling off several sub-disciplines that to me seemed, well, they didn’t seem organizable to me. Some of those sub-disciplines he had felt unqualified to teach. Both he and I are smart people and know that the other’s discipline can be organized and that there are differences between subdisciplines but the point is that for both of us there is a scale to the other’s discipline below which our intuition evaporates.
This seems very similar to what we are trying to give our students: the ability to mentally organize boxes of related information at both higher and lower scales. For instance all our students come in knowing that they have a heart and that it pumps blood (1:1 ratio). In Anatomy & Physiology they increase the magnification to learn the relationship of arteries, capillaries and veins (1:10 ratio), then the specialized structure of the red blood cells, and the endothelial cells that make up the vessel walls (1:100 ratio), then the subcellular structure of endothelial cells and red blood cells that matches their function (1:1000 ratio), then the function of individual proteins in those cells (the role of ribosomes in gene expression, the role of hemoglobin in oxygen transport) (1:10000 ratio). In my experience, the higher the aspect ratio (in either direction), the more abstract and difficult it is for my students to learn. Many times they are so overwhelmed learning the names of things that they don’t appreciate connections between the different scale levels… for instance how a ribosome (1:10000) in a bacteria can make a pilin protein which becomes part of a extracellular structure (1:1000) that allows the cell to stick to a layer of human epithelial cells in the mouth (1:10) and that we aren’t talking about one bacterial cell but a population of bacterial cells (10:1) expressing this pilin and that sticking better to the host can make a bacteria more pathogenic (1000:1). All because of something that happened at the 1:10000 scale.
In a sense, what I do is try to help students to (1) realize there is a scale thing going on and (2) develop their own ability to pack the information together at different scales.
* – whenever I say “virus” here, I mean “eukaryotic virus”. Of course there are viruses that infect bacteria, and to understand them you would have to study bacterial cells. But labs that worked on bacterial viruses were always hanging out with the bacteriologists and I with the eukaryotic cell biologists. You see the problem.