Iowa Alumni Magazine | April 2006 | Features

Me and My Microbes

By Tina Owen

The looks on their faces tell all—these undergraduates can't quite believe their professor's instructions. As they gradually realize they did hear correctly, they give thanks they're not in medical school.

"When we teach this course to second-year medical students, we send them off into the bathroom with swabs," explains microbiology professor Steve Clegg, who's leading this particular session of "Microbes and Our World."

These 30 students dotted around the lecture theater in the Seamans Center for Engineering Arts and Sciences get off lightly. They simply have to scrape their fingers along the inside of their mouths or nostrils in order to retrieve samples of bacteria, those tiny organisms that make their homes in our bodies—congregating by the millions on every inch of our skin, in our throats, noses, and lower gastrointestinal tracts. Grade schoolers are right—people have cooties.

Microbes, as they're more often referred to in the scientific community, include bacteria, viruses, fungi, and protozoan parasites. An unavoidable part of life, they exist on virtually every surface we touch, in the air we breathe and the water we drink. They flourish where we would perish—in volcanoes, industrial waste, ice caps, and other inhospitable environments. Luminescent varieties reveal their presence with an eerie glow, while magnetic bacteria chart a course for the North or South Poles.

As the semester progresses, students realize that these ubiquitous life-forms are more than simply odd, prevalent, or gross—they're also surprisingly influential. Bare billionths of a meter in size, these microscopic organisms have changed societies, improved national economies, and altered the course of human history. Says course director and associate professor of microbiology Rich Roller, "Both naturally and in the creative things that people do with them, microbes are part of our world."

Indeed, the course aims to help students appreciate the diversity and complexity of microbial life—and how essential these organisms are to human life. Microbes have a multitude of useful talents that we can harness. "Bacteria are chemists par excellence," adds Roller. "They do things that scientists with all their equipment can only do at great expense and effort."

Who puts the holes in Swiss cheese? Take a bow, Propionibacterium freudenreichii. This helpful little bacterium produces carbon dioxide bubbles that burst in ripening cheese. Lactobacillus sanfrancisco gives sourdough bread its distinctive tang. The Apergillus niger fungus produces enzymes that turn animal hides into leather, while Xanthomonas campestris provides the Xantham gum that thickens and stabilizes everyday products ranging from household paint to cosmetics. Microbes—in the shape of the Thermus aquaticus bacteria that makes an essential component of DNA testing—can even help track down murderers and settle a paternity suit.

The realization that these entities abound unseen in so many unsuspected places may turn your stomach or induce a frenzy of hand-scrubbing. After all, if someone says "microbes," most of us hear "germs." "This course can make you paranoid or you can accept that you'll never have totally clean hands," says Roller. "It helps you decide what's a reasonable and responsible level of cleanliness paranoia, and it shows it's impossible to isolate yourself from your environment."

Most human encounters with viruses or bacteria are harmless. After evolving together for millions of years, humans and microbes generally live in peaceful coexistence. Many of the bacteria on our skin actually defend us against more harmful organisms. Then there are viruses like herpes simplex, which causes cold sores. Although most people harbor the virus, only about 35 percent develop a cold sore. "I tell students that they likely have three or four viruses that are lifelong companions," says Roller. "I joke that they'll never find a friend as faithful."

Some of the most infamous and potentially deadly bacteria—syphilis, cholera, the plague—are the topics of several lecture sessions. That's when students get an inkling of how the course of human affairs can hinge on organisms whose inner workings still baffle and amaze scientists. How would European history have turned out if the Black Plague hadn't wiped out millions of people in the 14th century, or if syphilis hadn't spread through the mercenary forces recruited by King Charles VIII of France and ruined his plans to invade Italy in 1494? More recently, the AIDS virus brought issues of homosexu-ality into the open and created a new social discourse in America. "Epidemics have wrought really powerful changes in societies that have to face them," says Roller.

In terms of microbes' economic impact, Roller points out that "much of the developed world is now prosperous economically because we have healthy populations. We treat our water and food so they're not contaminated on a regular basis and we don't lose millions of children to viruses that cause deadly intestinal diseases."

Even students familiar with microbiology are usually surprised to realize the power and influence that these tiny organisms wield over human affairs. "Microbiology is a pretty recent development and it's really awesome to find out how far we've come in the field," says Chelsea Lloyd, a microbiology freshman from Quincy, Illinois, who describes herself as a micro nerd. "It's cool to learn how something so small can have such a huge impact on humanity."

Now in its third year, "Microbes and Our World" caters to non-science undergraduates as well as budding microbiologists. In an arrangement that's unusual for an introductory course in the College of Liberal Arts and Sciences, three professors—Clegg, Roller, and micro-biology professor William Johnson—teach the class, sharing their expertise in different areas. "One advantage of this expertise is that I can tell students fun and interesting stories that they might not get from someone who isn't a virologist," says Roller.

Of course, one person's definition of "fun" may not match another's. Students' reactions to the wonders of microbial life range from awe and amazement to disgust. In week four, they recoil in horrified fascination at the sight of the bacteria they collected earlier from their own bodies. More than 500 species of bacteria live in the human mouth, and, after incubating for several days in a Petri dish filled with nutrient-rich, blood-red agar, these samples have mushroomed into fuzzy black or grey colonies.

"It's pretty gross to know that human mouths are the filthiest in the animal kingdom, save the camel," says Lloyd. "If we think dog kisses are bad, just think about how nasty people kisses are! It makes me appreciate Listerine."

This class may be ripe with such "eeew!" moments, admits Roller, but it also provides students with a valuable perspective on their world. In an age where stories about microbes—from bird flu to antibiotic-resistant bacteria to biological warfare—fill the media, students need to respond to such reports in an educated and informed fashion. As Clegg points out, "A little bit of microbiology knowledge will go a long way."

To underscore these connections between microbiology and their lives, students submit written assignments in which they comment on media stories related to the class. For one assignment, Lloyd discovers that scientists are genetically altering bacteria to become photosensitive and act like photographic film. "It's a great 'development' in the field of synthetic biology," she jokes. "I didn't realize how easily bacteria can be manipulated to become useful to science." Such awe-inspiring and humbling revelations help cancel out the grosser aspects of this class.

"We try and give students an appreciation that microbes are really fascinating," says Roller. Perhaps it's the virologist in him speaking when he adds that microbes can also be things of beauty. When he flashes Powerpoint slides onto the classroom's wall-sized screen, though, his students are taken aback by an unexpected glimpse of the "germs" they thought they knew so well. Magnified and colorized to highlight their shapes and structure, these bacteria, viruses, and fungi look like modern works of art-cubes, spheres, and other shapes that dazzle in vivid hues of purple, green, orange, and blue.

"It seems weird to think of a virus as a beautiful thing, but if you envision it the right way, you can. Foot and mouth is an ugly disease but a pretty virus," Roller says. "It's good to give students perspective on these things. In their complexity and the way they work, microbes are really elegant organisms."