I ended that workday the same way I ended many days at my old job: alone, and in the dark. I sat in a room which acted as both an office and a microscopy room for the muscle stem cell lab where I worked as a technician. Evidence of the dual nature of the room was apparent even if you didn’t notice the huge microscopes that dominated the desktops. Binders full of invoices and catalogs dating back several years filled the shelves along each wall, just like you’d see in any office. Someone entering the room would be greeted by a heavy black curtain. This kept light from entering the room when the door opened — most microscopy works better without incident light. It also served as a warning that the room was occupied by bleary-eyed microscopists intent on their specimens, who wouldn’t appreciate being startled or made to lose their place. Microscopy was a big part of my job, so I often found myself in this room, with the lights out, past quitting time.
My eyes were glued to the eyepiece of the lab’s workhorse, a Nikon TE2000 “Eclipse” microscope. It was a venerable example of an “inverted microscope”, where the objectives — the parts of the scope that take in light and direct it to the eyepiece — are below the specimen. For technical reasons, this design generates a slightly better image, but it also lets you put a dish of live cells onto the stage and view them through the bottom of the dish without disturbing them, which I needed to do that night. It was late and I wanted to leave, but a lab tech never runs out of chores, some of which can’t wait till tomorrow.
I was checking to see how my colleague’s cultures were doing. Cell cultures are tricky to grow, and need to be monitored regularly. It was a tedious but necessary task I had done many times before. I settled in for another half hour or so of seeing muscle cells sloshing around and didn’t anticipate I would see anything new. Those late work days often made me wonder: aren’t there jobs that pay better and don’t require me to work evenings babysitting cells in a dark room?
There were better jobs, of course, but this was a job in science, which had entranced me growing up. It had seemed like an exotic, noble profession. The practicality of law and medicine never had the same appeal. Science combined the excitement of discovery with the enjoyment of solving a difficult puzzle. Hunched over the eye-piece of the Nikon TE2000, I began to realize these pay-offs would come between periods of difficult, often tedious work. Sometimes I wondered if it was worth it.
My practical training in science began when I was an undergrad and started working with a grad student studying Japanese quail. I made the same deal made by apprentices since time immemorial: do the menial tasks and eventually you’ll get to do the interesting, challenging work, too. Those menial tasks included mucking out bird cages, labeling test tubes, and lubricating probes to take the rectal temperatures of understandably jumpy quail. It did provide some pay-off moments, though. Helping the grad student develop a way to measure and manipulate the birds’ hormones was pretty gratifying. It helped us figure out how the stress level of the mother could be transferred to the offspring.
After my graduate student “adviser” graduated, I got a job in the muscle stem cell lab as a technician. My work involved isolating individual muscle fibers from mice and studying the stem cells that inhabit these fibers. I learned a lot of skills related to microscopy, cell culture, and molecular biology.
I learned these skills gradually, though. Much of my time was spent culturing cells, taking pictures of those cells, and then counting them. By hand. I didn’t get to design the experiments at first, and I didn’t have a good background in stem cell biology, so it was easy for me to feel like a factory worker, mechanically peering into the scope to check culture after culture.
The cell culture I was looking at at the moment had started out as a few isolated stem cells two weeks ago. In a mouse, these cells would divide and fuse with existing muscle fibers. In a petri dish, these cells can only fuse with each other. When just a few fuse, they look like a plump, transparent, slug-like lump of tissue with several nuclei in their cytoplasm. These “slugs” can grow quite large after a week or so, and start resembling tubes—like miniature muscle fibers. It’s difficult to keep these cultures alive much longer, though.
But now I was looking at a plate covered by these tubes. It was so dense that tubes were growing into each other, resulting in a large bulge of nuclei where they met. And now they didn’t just look like muscle fibers—they started acting like them. At irregular intervals, the largest fibers would twitch. I jumped when I saw it. Each tube was beating at its own rhythm, flexing and contracting with no particular purpose. No one had warned me they would do that, and I didn’t expect it. Why should I? They’re just muscle cells—no neurons could tell them when to twitch.
The next day I told my supervisor, who wasn’t surprised at all: that’s simply what happens when muscle cultures become really dense. It wasn’t a eureka moment, then, but more of a wow moment.
But the eureka moments aren’t the only ones worth reveling in — it’s also the wows. Those long trudges between moments of discovery can take you through some bizarre, interesting places. I guess I would have been home earlier if I had another job, but then I would have missed the mass of writhing, twitching muscle — a graphic, memorable illustration of the regenerative capability built into our bodies.
Joshua Richardon is a postdoc studying the microbiome and microbial genomics at the US Army Research Institute of Infectious Diseases.