Gut Reactions

Beneath the powerful eyepiece of the Axioplan microscope, Leadbetter cranks up magnification and invites me into his world. “It’s like being an ecotourist in Wonderland,” he says. And indeed it is. In the microscope’s circular view field is a teeming miscellany of exotic beasties, a little alien universe populated by creatures as strange and comical, and somehow as endearing, as one of those kitschy bazaar scenes in a Star Wars prequel. The most common type have a long, thin corkscrew form; these are spirochetes, closely related to the bacteria that cause syphilis. There are protozoans resembling miniature snails, and inside their single-cell bodies are small pieces of red stuff. That’s wood, Leadbetter tells me. My favorite type is the one that looks like a sea lion, which snuffles around with its “nose” twitching, apparently searching for something. The “sea lion,” whose Latin name is Trichonympha, has long cilia trailing from its body that helps it swim. All of these organisms propel themselves by chemotaxis, charting paths along chemical gradients in the water.

Leadbetter has been studyingthis microbial Serengeti for the past 16 years, but he is constantly seeing new species he has not yet identified. It’s a daunting task simply to catalog the different types, let alone to understand what each one does. “Why,” for instance, “are there 100 types of microbe, and not just one?” he asks.

A protozoan

Related Content

• John O. Dabiri: The Jellyfish Genius
  May 15, 2013
• L.A.'s Scripps College Olive Oil Wins at Los Angeles International Extra Virgin Olive Oil Competition
  April 5, 2013
• Earthquake Warning System Worked During Anza 4.7 (VIDEO)
  March 13, 2013
• Bicyclist Hit Near Caltech, Dies
  June 17, 2013
• Earthquake: Big One Involving Los Angeles And San Francisco Possible, Says Caltech
  January 10, 2013

More About

• Jared Leadbetter
• California Institute of Technology
• Henry Moore
• Sciences
• Science and Technology

These microbes are one of the major reasons termites are such legendarily social creatures. When a new termite hatches from its egg, it has no gut flora; it must be fed its microbial complement by another termite. Leadbetter is particularly taken by this fact — termites are alive today because millions of generations of termites before them have handed on their gut flora to the succeeding generation. It’s an insectoid version of the Catholic Church’s apostolic succession, in which each new priest is fed the communal wafer by his father-confessor. Termites have no theology, of course, but their survival as a species depends on this pan-generational passing of the torch.

Leadbetter and his colleagues are trying to understand what it is exactly the microbes do. They are beginning the process of making a cross-genome map of all the DNA collectively operating in the gut colony. Ideally, they would like to sequence each microbe separately. This kind of very basic biology is what we need to understand if we are ever going to work out how to efficiently turn wood into ethanol. As Leadbetter notes, “Making ethanol is not hard; making it from wood is the problem.”

I asked Leadbetter how long it might be before wood-to-ethanol is economically feasible. Clearly, it’s a question he’s heard before — not least from the venture ­capitalists whose calls he usually ignores. “It all depends,” he answered, “on how much we are prepared to commit to doing the underlying science.” Unlike, say, particle physics, termite-gut ecology is complex stuff. It has taken nature a billion years to get to this point; it will take scientists at least a few decades to learn the ground rules. We ought not be priming the pumps just yet, Leadbetter suggests. But the end of oil is definitely nigh, and we must begin to look seriously for other fuel options. As prices climb at the pump, who knows, maybe this country will again get serious about supporting basic biological science.