It doesn’t take a philosopher to answer the question of “What is life?” According to science writer Carl Zimmer, the popular blogger behind the Loom, the answer can be found by studying Escherichia coli, a common bacterium living in your gut. “E. coli is an oracle,” he says, that tells about life and how life works.
Zimmer is a recent expert in the beauty and history of this bacterium, the topic of his new book “Microcosm: E. coli and the new science of life.” Wearing a tie covered in pictures of microbes, he told fans at the Harvard Book Store yesterday evening that he wanted to write about this “unjustly neglected” player in biology, because its scientific contributions are often unknown to the general public.
German pediatrician Theodor Escherich first discovered the bacterium in 1885 while investigating a string of childhood illnesses. As he looked at samples of sick children’s diapers under a microscope, he observed thousands of fast-growing rod-shaped bacteria. Since then, the bacterium has become a model organism for many scientific experiments. A French researcher once said, “What is true for E. coli is true for the elephant.”
The bacterium is popular because it is easy to grow, a crucial characteristic for bioengineering. The gene for insulin, a hormone produced by the pancreas and used in the treatment of diabetes, is routinely placed in E.coli. As the bacterium multiplies, scientists harvest the insulin and sell it in giant vats – much better than the previous method of stealing pancreases from butchers.
Zimmer, with the help of a fist-sized stuffed model, gave an enjoyable description of E.coli. He demonstrated the way it coils its hair-like flagellum to move forward, and then uncoils them to tumble around a Petri dish as well as the “nose” it uses to detect which tasty molecules to move towards. He even showed E. coli sex, which consists of a bacterium protruding a long tube to another bacterium, and exchanging genes.
Just as E. coli redefines the meaning of sex from the “exchanging of gametes” to the “exchanging of genes,” it also redefines other aspects of living organisms. Different strains of E. coli are found in nature, and even more are produced daily in labs. Despite their genetic differences, they are still considered the same “species,” making biologists question the definition of species. E. coli has been manipulated so much that some strains have fragments of DNA matching no other organism.
So, next time you hear mention of E. Coli, don’t think food poisoning – think knowledge.
Story and photograph of Carl Zimmer by guest blogger Mai Nitta.