The COVID Digest, 16Jun2022
On the road, part 2
This week my family is still on the road on our journey from Kansas City to Yellowstone National Park and back. You may have heard that Yellowstone National Park made the national news due to massive flooding that shut down the park. We were in the park that day. More on that experience in a bit.
My husband and kids and I had never been to Yellowstone, but it was somewhere I’ve wanted to go since I first started learning about molecular biology. And that’s the basis for today’s science lesson that I’m excited to share with you.
A big portion of Yellowstone National Park is a not totally dormant supervolcano where there is a lot of hydrothermal activity in the form of geysers, hot springs, fumaroles, mud pots and more. There are many areas where humans are not supposed to walk, because the crust that separates above ground from below ground is really thin, super hot, and sometimes acidic. As the National Park Service repeatedly warns, Yellowstone is a dangerous place. That doesn’t stop bison from walking onto that crust, but it led to several really stern conversations with my boys about staying on the boardwalk, not running or shoving. The ground seems to be on fire in many parts of the park.
One of the main attractions of Yellowstone National Park is the Grand Prismatic Spring (shown below, not my image) and it was the thing I was most excited to see.
There is a boardwalk that visitors can walk on to see the pool from ground level. From here, it’s hard to see the whole thing, but you can feel and see the steam. In a picture like the one above, you don’t see the steam, likely because it was taken on a really hot day. While we were there, the spring was completely covered in steam unless a good wind blew it off. From ground level, it was hard to see the green and blue parts of the spring. But you could see the color reflected in the steam. You can gain a sense of how it appeared at ground level in the photo below. If you want to be elevated and able to see the full Grand Prismatic Spring, use the Fairy Falls trail near the Grand Prismatic Spring parking lot. The best time to visit is midday on a sunny and hot day to see the best colors and as little obscuring steam as possible.
The Grand Prismatic Spring is the largest hot spring in the United States, discovered in 1871. The average water temperature is 160 degrees Fahrenheit and it measures 160 feet deep by 370 feet wide. That is some hot water, but not quite boiling (about 212 degrees Fahrenheit). The color we see at the edges - green, yellow and orange are because of pigmented bacteria that are uniquely adapted to surviving at a particular temperature on a gradient of hot to cold. The center of the pool (blue) is thought to be sterile because it is the hottest part of the spring. In the photo above of my boys, you can see some of these bacterial mats (in brown) that form what look like flat rocks, but they’re made of bacteria. It’s a pretty cool thing to think that thousands of people flock to Yellowstone’s Grand Prismatic Spring every year to marvel at a hot spring full of bacteria.
But bacteria like the ones found in the Grand Prismatic Spring are important for more than just their looks. These are called thermophiles where “philes” means loving and “thermo” means heat. In other words, these are organisms that love hot water or hot conditions. One of my boys asked if they could make us sick. Most likely no, because they’re adapted to living at 160 degrees and their body temperature is 98 degrees. Just like we feel sick and not our best outside of our optimal temperature range, the bacteria function in much the same way. But their ability to survive hot temperatures is important for molecular biology, particularly Polymerase Chain Reaction (PCR) which is the technique used as a gold standard diagnostic test for COVID-19 and other diseases.
PCR is basically a big copy machine for DNA (or RNA). But in order to make those copies you first need to pull the twisted ladder of DNA apart and then use an enzyme (a type of protein) called a DNA polymerase to make the new DNA using the newly pulled apart DNA as a template. DNA melts or denatures at 95 degrees Celsius, nearly boiling temperature. Our bodies run at 37 degrees Celsius, so our DNA polymerase enzymes can’t be used for this. That’s because if you heat a protein too much, it can also denature, sometimes irreversibly. Think of how egg white transforms from a clear liquid to a white solid when you fry an egg. That’s denatured protein. So the challenge was to find a DNA polymerase that could survive high temperatures that would melt or denature DNA, but still be functional to do the DNA copying afterwards. Organisms that live at high temperatures have enzymes that run at high temperatures.
Not far from the Grand Prismatic Spring is the Mushroom Pool in the Lower Geyser Basin at Yellowstone National Park. This hot spring is not marked on the visitor routes nor is it searchable in their app. So I suspect this one might be more remote or hard to access, requiring a permit. But this is where Thomas Brock found Thermus aquaticus, a bacterium that could survive in boiling water, in the late 1960s.
Separately, an American biochemist named Kary Mullis was trying to invent PCR. But he ran into the problem described above: you needed an enzyme stable enough to withstand high heat and still perform the job. He was awarded the Nobel Prize for his invention of the PCR technique in 1993. It has revolutionized molecular biology research and diagnostic testing. So it was a shame to not be able to access the Mushroom Pool to sort of pay homage. But maybe it was good enough to nerd out over some of the cousins of Thermus aquaticus at the nearby hot springs.
It goes to show that we should continue to support and get excited about basic research - the things that may or may not have a direct human benefit. Because those discoveries are sometimes the things that lead to enormous progress in human applied research fields.
I mentioned that we were in the park the day the flooding happened. In fact, all of my photos above are from the day of the floods. It was raining that morning and we were warned at the south entrance that much of the north loop was closed due to high water. The Park has really bad cell coverage, so we didn’t get alerts or other warnings as to what was happening. When we arrived at a place in the park with decent coverage, we found out all the gates had been closed for inbound traffic but we didn’t know why. We figured with the north loop being closed they just wanted to control overcrowding of the park. In a way, it felt like a gift of a day because we could go see the things we wanted to see without the usual crowds.
As we progressed, we stopped in to the Old Faithful Inn to use the restroom and we overheard someone saying that we made the national news due to flooding. But we still didn’t know how bad things were. No one at the hotel was panicking, or encouraging anyone to leave, including staff and park rangers.
About mid-afternoon we again bounced into a spot with decent cell service and our phones buzzed repeatedly with alerts and panicked texts from friends and relatives asking how we were. It was then that we understood that the entire park was being closed, all employees were being sent home, and we needed to leave.
We certainly weren’t expecting to be part of history on this vacation. We were among the last people to see Yellowstone National Park in the state it was in prior to the floods. The brochures all say that “Yellowstone is a dangerous place.” But I think they’re typically referring to bears and hydrothermal features, not a catastrophic flood. I hope they are able to repair the damage as quickly and safely as possible. One of our big reasons for going this year was that we wanted to see the park before climate change altered it any more. So I’m really glad we went when we did.
COVID-19 is not over, of course. In fact, the map below shows the community transmission levels throughout the country. The country remains on fire with COVID-19, as people go on about their lives. Disease is declining in the northeast, where this wave began, but rising elsewhere.
Another bit of news is that Dr. Anthony Fauci has COVID-19. I certainly hope he gets better soon and has an uneventful case. But it was an interesting point of pride for me to say that I outlasted Dr. Fauci. Maybe you have too.
The biggest news of the week, however, is that we are finally getting vaccines authorized for children 6 months to 5 years old. I know this will come as a relief to many parents who have struggled to protect their kids from this pandemic.
That’s it for this week. Next week’s newsletter will be back to the usual content as our vacation comes to an end.
Thank you for your support of the COVID Digest.
My Ph.D. is in Medical Microbiology and Immunology and I am Chair of the Division of Natural Sciences and Mathematics at the University of Saint Mary. I've worked at places like Creighton University, the Centers for Disease Control & Prevention and Mercer University School of Medicine. All thoughts are my professional opinion, do not represent the views or opinions of my employer and should not be considered medical advice.