7 Things you don't know about microbes
. . . but probably should
By Becky Beyers
Microbes are, literally, everywhere: In our guts, in soil, in plants, in food, in water, maybe even in outer space. Across the college, CFANS researchers are finding new ways to unearth the magic of microbial science. Until recently, researchers could only study microbes by growing a culture in labs, but new sequencing and molecular tools have made the difference over the last decade, fundamentally changing how scientists understand what microbes can do.
But what does the average person really know about microbes, anyway? Here are seven things you may not know about microbes or microorganisms (but probably should):
- There are a LOT of microbes in the world
Really, a lot
"A little gram of soil that's the size of the tip of your pinky has 10 million microbes," says Linda Kinkel, professor in the Department of Plant Pathology. "What they can do biochemically, physiologically—it's more fascinating than our imaginations can even dream of. Without microbes, all life would grind to a halt."
- Which came first, the plant or the microbe?
Sometimes it's hard to tell.
For example, Kinkel tells the story of the anticancer drug Taxol, which is produced from a substance found in the bark of yew trees. Two to four trees are needed for a single dose of the drug, but demand for Taxol is so great that within a few years after its cancer-fighting properties were discovered, the trees became endangered from over-harvesting. Eventually, scientists figured out that the basis for the drug can be found in the microbes that live on the trees, not the trees themselves, and now the drug can be manufactured without cutting down so many trees.
- Surviving the most extreme conditions?
Those bubbling hot springs at Yellowstone National Park? They're full of what's known as extremophilic microorganisms—they've adapted naturally to survive in the extreme conditions of more than 200 degrees F and very low PH. Scientists look for these microorganisms via a process known as "bioprospecting." Rob Gardner, associate professor at the West Central Research and Outreach Center, bioprospects in his research on algae as a source of renewable energy. While algae has highly promising attributes for fuel production, it contaminates easily, so scientists have to create growth conditions inhospitable to almost everything except algae—and the same microbes found through bioprospecting in places like Yellowstone. Those microbes may be useful in growing clean algae for fuel.
- They're the good guys
Like tiny superheroes, microbes work together to solve problems.
When people think of microbes, they often focus on disease-causing organisms. But most of the microbes on the planet are beneficial, says Michael Sadowsky, professor in the Department of Soil, Water and Climate. They carve out a niche, like the human body, where they form mutually beneficial, or commensal, relationships. They actually help the body fight disease, process food, and assist in a host of other functions. In fact, there are more microbes in the human body than human cells in the human body. There’s a connection between the microbes in your gut and brain activity, for example, that tells you when you’re hungry, when the food you ate is not very good, and even what to do about it.
- We are what we eat
Microbes can make food taste better and last longer.
From that first sip of coffee in the morning to the digestif you may have drunk after a meal, microorganisms play a role in almost all the foods and beverages you consume every day. In many ways, microorganisms have been our first food processors that have helped to shape the diets of humans. Prior to refrigeration, we had to rely on other methods to make our foods last throughout the year; many of these foods were fermented to make them last longer and some even taste better after fermentation. David Baumler, Assistant Professor with the Department of Food Science and Nutrition, is combining new methods of systems biology and genomics with food microbiology to start to understand the full complexity of the metabolic capabilities of yeasts and microorganisms, which will help optimize fermentation processes for better and tastier food and beverages.
- Their roots run deep
These are some serious family ties
When plants grow in soil, they form very close associations with microorganisms near their root systems and on the root surface, Sadowsky says. The number of microorganisms in this area, referred to as the rhizosphere and the rhizoplane, can be 10 to 100 times greater than the number living in the surrounding bulk soil. For plants like wheat, with especially large root systems, the number can be up to 1,000 times greater. They thrive on those very rich carbon, nitrogen, and phosphorous nutrients that are released by plants in a process called rhizodeposition.
- To prevent disease, eat lots of different foods
But not if you're a microbe.
Globally, scientists have found multiple cases of naturally occurring disease-suppressing soils, including one in Minnesota. These suppressive soils support high densities of antibiotic-producing microbes that kill plant pathogens. In every case, a monoculture—a single type of plants—has been growing in the soil for many years, Kinkel says. She’s duplicated the phenomenon in a long-term research trial at the U’s Cedar Creek Ecosystem Science Reserve. But monocultures are supposedly bad because they increase plant disease, Kinkel says, so how can they be good for disease suppression? It’s all about the microbes’ ability to fight pathogens, especially via antibiotics. “If you’re a microbe, and you’re in a setting with diverse plants, the different plants provide lots of different things to 'eat.' This means there may be little benefit to producing antibiotics to kill off competitors, so antibiotic-producing microbes decline in abundance. However, in long-term monoculture, food options are more limited. Antibiotic production offers a great means for fighting off competitors, including pathogens, and guaranteeing access to food. This model explains the association of long-term monoculture with antibiotic-based disease-suppressive soil communities, and suggests that nutrient management may be a valuable strategy for creating disease-suppressive soil communities in agriculture.