Wednesday, July 25, 2012

Angel's Glow, Under a Microscope

Sometimes the same science story can look very different depending on how you tell it. Instead of angels, you find worms. But that's not necessarily a bad thing.

This is what happened with "Angel's Glow." The Civil War caused a Judgment Day's worth of carnage and flesh wounds. Army doctors noticed that some soldiers' wounds glowed with a faint blue light, and that these wounds were almost always clean from infection. They called this the Angel's Glow of protection, and no doubt were thinking of angels that did it.

When science looked into the story it found no little dancers on the ends of pins, although it did find something that could dance on the end of a pin if so inclined. It found tiny "bugs," microbes that contained the glowing blue light. Science named these microbes Photorabdus luminescens, and you can find out all about them at their Microbe Wiki page (I did not know such a site existed, but it sure makes sense). That site has a nice picture of the blue glow coming from waxworms infected with Photorabdus:

Part B shows the same bacterium inside a different worm, Heterorhabditis bacteriophora. (Yes, I know it's green, not blue: they "painted" it that way with a green-glowing protein, so that shows what happens when you mix biological glows, I guess.) The interesting thing about this infection is that it's actually good for the worm. Photorabdus likes to be the only bacterium on the block, so it has developed an arsenal of potent and creative antimicrobial molecules that it lobs around the environment, taking out most other bacteria. Heterorhabditis apparently doesn't mind the antimicrobials, because they destroy bad bacteria that might infect it. So the worm has made a handshake deal with the bacterium: I'll give you a place to live (and a set of wheels to get around) IF you'll take out the other bacteria. And it seems to work very well, because Photoradbus is able to kill a lot of other things. It's an effective little bug, it just needs a worm to give it a ride.

Gardeners apparently use this worm all the time to kill ants and other insects. Now we know that this works because of the "Angel's Glow" -- the worm spreads the glowing bacteria around the garden and it goes its little glowing way, spreading insect death and destruction while sparing the life of its wormy host. Photorabdus even likes to take two forms, one of quiet little colonies inside the Heterorhabditis worm-car, but then it transforms into Superbad-Bacteria when it gets into the insect. A fascinating transformation, found in other small organisms like Malaria. I'd love to know more about how that happens at the protein level.

So how should this story be told? The blog post that first alerted me to it is titled "Worm Kills Insects by Vomiting Hulk-Like Bacteria." Well, that would work a little better if the Hulk were blue, but it was good enough to attract my attention. My thoughts on reading it is that the blog tells its story explicitly, in vivid, gross terms, dwelling on what a horrific death it must be for the insects. Ok, that's true but it's an editorial emphasis. I also found  happy gardeners, worms, and soldiers in the story. The horrific death is occurring to some organisms that have a pretty bad effect on the environment (whether they would be killing a soldier or ruining a garden given the chance). If you're pro-insect you can lobby against this process but I'm not so sure it's a bad thing for the pro-human people among us.

What this really is, is a case where the story reveals something about the storyteller. The storyteller can't help but put himself into the story. The story itself is a complex and networked mix of good and bad. It's gross but it's also beautiful, with the image of glowing wounds protected from further harm. It's something that has been harnessed by human ingenuity (and before that, by biological ingenuity) to create and maintain order. So you can talk about it with images of death and vomit, and I'll talk about it with images of well-manicured gardens and fathers who could return to their families because of a mysterious, ethereal blue glow. You may see demons-- but I see angels. It's all in the looking. (... when he looked up, he saw that the hillside around Elisha was filled with horses and chariots of fire ...)

And who's to say angels AREN'T there? After all, haven't you ever seen The Ten Commandments, with its depiction of the Angel of Death? Looks pretty familiar to me ...

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