TERMITE TUMMIES REVEAL NUTRITIONAL POWERHOUSES
EAST LANSING, Mich. - Secrets of energy conversion - and maybe the ways to make cows produce less gas and more milk - might lie in the belly of a termite, an MSU microbiologist reports.
The gut of termites houses one of the densest and most diverse microbial populations in nature, with 65 percent of the volume of the gut packed with microbial cells. John Breznak, Michigan State University professor of microbiology, has discovered that some of these microbes have the astonishing ability to convert intestinal gases of termites into a useful nutrient. The findings are reported in the Jan. 29 edition of Science Magazine.
"Studying termites is important in understanding how complex communities of microbes function with each other and how they interact in a mutually beneficial way with the animal," Breznak said. "If one is interested in digestion you can learn a lot from all kinds of animals."
The microbes Breznak's team focused on are spirochetes, corkscrew and wavy-shaped bacteria that are present in unusually high numbers in a termite's gut. While they've been known to be residents there for a century, Breznak's team is the first to isolate them and culture them in a test tube.
Once that was accomplished, they found that the spirochetes are able to take hydrogen and carbon dioxide - which are important intermediates in digestion of wood by termites -- and turn it into acetic acid.
Acetic acid - which essentially is vinegar - and is an important nutrient for the termite. It provides up to 100 percent of the termite's daily nutritional needs, and it looks like spirochetes can provide as much as a third of it from these simple gases.
"So termites are eaters of plant material, but really it's through the action of the termites' own enzymes as well as with the assistance of microbes that they actually extract most of the nutrients from the food they eat," Breznak said.
Discoveries made with termite tummies could provide answers to problems elsewhere. For example, cattle stomachs also are host to a variety of microbes that assist the animal in digesting food. The big digestive difference between cows and wood-eating termites is that microbes in cow stomachs take the hydrogen gas and carbon dioxide and converts it to methane.
Cows can't use it, so they belch it out.
This is a loss of energy for the cow and also increases atmospheric methane, a greenhouse gas that contributes to global warming. Understanding how spirochetes create nutrition from these gases in termites could provide clues to make a cow's microbes work more efficiently.
"If cows could have some of their microbes convert more of the hydrogen and carbon dioxide to acetic acid instead of methane, that would mean more milk, meat and fiber per kilogram of feed," Breznak said. "I have a hunch farmers would be very happy about that.
Another benefit: Since certain spirochetes also cause ailments such as Lyme disease, syphilis and periodontal disease "what we learn from one group may also help us understand the more notorious members," Breznak said. In addition to Breznak, J. Leadbetter, T. Schmidt, and J. Graber are listed as authors on the Science paper. The research was funded by the National Science Foundation.
"Termites are remarkable animals with their gut flora - it's like looking at an orchestra," he said. "There are violins playing here, flutes over there and chimes way in back. The overall sound quality is a reflection of how many instruments there are and how well they perform together."
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