Mysterious Microbe Offers Clues to How Cancer Works

A tiny aquatic microbe that has been swimming around the planet for more than a billion years has stunned scientists who have discovered that it has a sophisticated communications network that is more elaborate than that found in higher life forms, including humans. What makes the finding particularly surprising is the microbe has only one cell, so it's sort of like living in a community with only one telephone. Who are you going to talk to?

The microbe, known as Monosiga brevicollis, has fascinated scientists for more than a century because it could be the bridge between fungus and multi-celled animals, and thus, the pathway the first organisms followed into the animal kingdom. We share some of the same genes, tyrosine kinases, except the microbe has a lot more of them, 128 to just 90 found in humans.

That particular gene allows the cells in a human body to talk to each other, and respond to external stimuli, talents that would seem to be of little use to a single-celled organism.

Earlier this year scientists from several research institutions completed mapping the microbe's genome, but when some of them took a closer look at the data, they found far more kinases than they had expected.

"We were absolutely stunned," said computational biologist Gerard Manning of the Salk Institute for Biological Studies in La Jolla, Calif. Manning is the lead author of a report on the findings in a recent online edition of the Proceedings of the National Academy of Sciences.

This particular microbe has been suspected of being at least part of the bridge to the animal world, and the first critter across the path is believed to have been the sponge, Manning said in a telephone interview. If that's true, then another gap in the evolutionary trail has been closed, but that's not the only reason scientists are excited over the findings.

It turns out that this very simple microbe is a lot like us, and the more we understand it, the more we are likely to understand ourselves, Manning said. It's important, he added, because the same gene that gives the microbe the ability to communicate is implicated in most forms of human cancer.

"One reason this kind of research is important is we don't really understand our bodies," he said. "We don't fully understand how we work, and how things break down in disease. My background is working on these kinases in cancer. While this isn't going to directly cure cancer, it's going to help us learn more about the fundamentals, and sooner or later, that will trickle down into understanding humans, and understanding sick humans.

"If we understand kinases, we will understand more about cancer."

Of course, that's not the only reason. It's also because it's "amazing," he added.

The microscopic microbe is found in nearly every body of water, from the Arctic to the swamps of Florida. While no fossils have been found, scientists are confident it was here more than a billion years ago because of genes it shares with fungi that came before it, and animals that came later, especially the sponge, where many believe it all began.

And as might be expected, they live a pretty simple life, which probably hasn't changed much since the very beginning, although nobody knows all that much about them. Scientists don't even know if the microbes have sex, or reproduce by dividing.

So, it's no surprise that no one knows why the microbes, that have survived all these years by eating bacteria, have such an extensive communications system, but Manning has a hunch.

"These organisms spin around, and that causes bacteria to swim into them," he said. "They have a little collar that traps the bacteria, then they eat them. So, you could guess they need to talk to the bacteria, or find out when they've landed on them, and that's communication."

And it's quite possible, he added, that they do talk to each other, at least when they are nearby.

At this point, the microbe appears to be the "first one-celled organism that looks so much like humans," at least genetically speaking, Manning said. But this research is only one element in a rapidly growing scientific field that affects virtually everything we know about life on Earth.

For decades, scientists were left with yeast and fruit flies and that worm, C. elegans, to piece together the genetic framework for life. But the rage now is to complete the genetic story, or the genome, of every creature, and that is changing everything.

It is a very good time to be studying genetics.

"It's amazing," Manning said. "I never stop thinking how lucky I am.

"I'd like to think that, in a thousand years, this is the stuff that people will still know," he added. "They will have forgotten about George Bush and Iraq and the Dow, but this is the stuff we are made of."

Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.

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