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06/30/2017
Deceptive Plants and Animals
CHAPTER 82 Revisiting Lichen and Other Topics
Long time readers will know that for many years I wrote a weekly column for this Web site. It was in 2010 that I began writing just one column a month. In the first of these monthly columns (dated 1/28/2010, see archives), I expounded at length about lichens and the fact that a lichen is not a plant or an animal, but a combination of an alga and a fungus. You see lichens on trees and rocks and all over the place, worldwide. Accordingly, I was intrigued when I read an article by Erica Gies titled "The Meaning of Lichen" in the June 2017 issue of Scientific American. In her article Gies deals primarily with the work of Trevor Goward, one of those mavericks who holds no scientific degree but whose keen and extended observations of lichen in Wells Gray Provincial Park in British Columbia has inspired work by others that has profoundly influenced the field of lichenology.
The worlds of algae and fungi are not only interesting scientifically but have a very practical side. Take the case of one fungus, the mushroom. Just the other day, I served my wife some Campbell's mushroom soup to which I added some pan fried mushrooms from our local Acme store. While I felt comfortable serving the mushrooms, I also knew that some varieties are poisonous. In fact, toxic species of mushrooms number in the hundreds. The same situation holds for lichen. One form of lichen, known as horsehair lichen has long been a traditional food for First Nation peoples in British Columbia. This brown colored lichen contrasts with the yellow colored tortured horsehair lichen, which you do not want to eat. It's poisonous! So, what's the difference between the two forms? Surprisingly, analyses showed that the edible and toxic forms of these horsehair lichens are both composed of the same alga and fungus! Weird!
Here's where Trevor Goward comes into play. Goward is one of those old fashioned types of curious individuals with a remarkable sense of observation and a keen interest in the nature of stuff that surrounds him. Years ago he observed lichens in the Wells Gray park and ever since has spent huge amounts of time observing their habitats and characteristics, so much so that he has written many papers and essays on lichens and has become renowned for his works on these symbiotic organisms. Apparently, given his lack of a scientific degree, some of his writings have engendered controversy and even ridicule. Toby Spribille, a University of Montana botanist, is one who definitely is not one of those critics and is quoted as thinking Goward's essays are brilliant.
Inspired by Goward, Spribille hooked up with John McCutcheon, a microbiologist at the University of Montana, to begin analyses of the DNAs of the toxic and edible forms of the horsehair lichens. Judging from the host of co-authors who joined Spribille and McCutcheon on a groundbreaking paper published last year in Science, this effort expanded to include workers in Europe. What was the groundbreaking news in their paper? For well over a century, back to the 1860s, it has been known that a lichen is a partnership between an alga and a fungus. The alga , through photosynthesis, provides the food for the fungus. This partnership is a classic model of symbiosis, in which one organism helps another. Later, some lichens were found to contain cyanobacteria as the provider of the food for the fungus. (We all owe our existence to cyanobacteria, the organism that was responsible for putting oxygen in our atmosphere billions of years ago.) What Spribille and his colleagues showed in their Science paper was that in some lichens there is a third partner, a new form of yeast. This yeast is different from the yeasts used to make bread or those used in making our beer. The yeast is a fungus in the so-called Basidiomycota family that includes mushrooms and other types of fungi. The researchers found that there were significant amounts of the yeast in some forms of lichen, notably in the poisonous yellow horsehair lichen. In contrast, the edible brown horsehair lichens sampled had little or no yeast in them. I guess the lesson to be learned is to choose your lichens as carefully as you choose your mushrooms to dine upon.
The DNA work of Spribille and his colleagues suggest that the yeast had developed along with the other components of the lichen for over 100 million, maybe even 200 million years. A major thrust of Gies's article in Scientific American is to promote a kind of back-to-nature approach a la Goward and Thoreau , as opposed to strictly working in the lab to determine how nature works. She points out the work of a friend of Goward's, Stuart Crawford, an ethnobotanist. Crawford collected writings dating from a European cookbook of the 1950s back to ancient Egypt in which mention was made of using lichens to bake bread and ferment alcoholic beverages. Unwittingly, those folks seemed to know that there was yeast in some lichens long ago!
Sometimes it's difficult to distinguish one form of life from another. In the July 2017 issue of National Geographic there's a fascinating article by Laurent Ballesta on life in the waters below the ice in Antarctica. Ballesta describes the challenges of making your way through a hole drilled in the 10=foot thick ice and exploring the world in the salty water below the ice at temperatures of 29 degrees Fahrenheit, below the 32 degree freezing point of pure water. It takes real stamina and courage to drop through that hole and count on being able to manage getting back through the hole before it closes up. Ballesta says it took seven months for him to recover from the nerve damage he suffered during his dives into the harsh conditions. Among the photos in the article of life below the ice was one of a feather star, an animal that I would swear was a plant. The animal has what looks like at least a dozen arms that look like fronds of a plant. I was so impressed with the picture that I Googled "feather star" and I strongly suggest you do the same. You will come across films of these amazing creatures swimming. Some of them don't look as plant-like as the one pictured in the Geographic article but they are all unique examples of aquatic life.
Now for another weird story, this one about the possibility of using one's own body to power a heart pacemaker. My wife's brother who is 94, recently debated whether at his age he should undergo surgery to replace the lithium battery powering his pacemaker. He did have it replaced and is doing fine. Could there be in the future a pacemaker powered by the body itself - no battery needed? The July/August issue of Discover magazine contained an article titled "The Body Electric" by Stephen Ornes. The article features the work of Canan Dagdeviren on piezoelectric materials. Dagdeviren and I share something - the origin of our interest in science. Her interest in science was literally sparked when she was 7 years old on an outing for a picnic in the forested hills near her home in Turkey, where she was born and raised. After gathering wood for a fire , her mother took two rocks and pounded them together forming sparks to start the fire. Seeing fire come from rocks really impressed young Canan. I too was inspired by sparks as a child less than 7 in Denver, Colorado. I was out in a field with a neighbor, Clarence McComas, an older boy. He struck a rock with a metal rod of some sort and sparks lit up the evening darkness. I was amazed.
But let's get back to piezoelectric materials. These are materials that generate a charge when you flex or bend them and they return back to their original shape. Dagdeviren was intrigued by them and got a fellowship to come to the USA to get her PhD at the University of Illinois at Urbana-Champaign. There, she worked in a group headed by John Rogers, a Bell Labs alumnus, whom Dagdeviren calls the "king of flexible devices". Rogers' lab was known for producing devices involving flexible, soft materials. While in his group, Dagdeviren came up with a flexible device that looks like a sticker that could be placed in the body to take advantage of motions of the lungs or diaphragm to flex the piezoelectric material and generate charges in the process. The charges generate a tiny current that could be fed to a pacemaker, which doesn't need much current to control the heart beats. Apparently the device has been tested on cows and who knows? People like my brother-in-law may not have to undergo surgeries to replace that pesky battery.
Incidentally, Dagdeviren is now starting up a group at MIT working on various kinds of flexible and sticky medical devices that might be used for sensing different bodily activities, properties or functions. Dagdeviren's work here in the USA exemplifies the value of encouraging immigration or extended stays by individuals from other countries. This isn't true just for science. With my wife's increasing interactions with healthcare workers, especially caregivers, we find the overwhelming majority to be from other countries. Right now, we have a very nice young woman from a country bordering Turkey coming in several days a week. In the past month or so, I've discovered and become a fan of Morning Joe. Need I say more?
Next column on or about August 1, hopefully.
Allen F. Bortrum
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