12/15/2010

TALK RADIO . . . AND ARSENIC



Hello, people who care about science education! I hope you are well and enjoying the buildup to the holiday season.

As it so happens, I will be back on the Alan Autry radio program (1300 KYNO) on between 11:00 and 12:00 on Tuesday morning, Dec. 21st. Regular readers of my blog may recall my first steps into this arena, and the considerable amount of traffic and comments it generated....so it will be interesting to see if this will be more of the same. I kind of doubt it, because just today Autry has announced that he will be stepping down from the program to pursue other interests. Here's hoping that his decision will not impact my understandable desire to spread a little science mojo!


Speaking of which . . .






I've been asked to address the exciting recent finding of bacteria in Mono Lake which are not only able to tolerate that body of water's extreme salinity, but which (evidence suggests) may be able to substitute arsenic (As) for phosphorus (P) in the building of the macromolecules of the cell.

It has been shown that these bacteria, when removed from the lake, continue to grow (at a reduced rate) on media that contains arsenic, but with virtually no phosphorus. This may mean that these bacteria have worked out the trick of making arsenolipids rather than phospholipids, AT(As) instead of ATP, and perhaps even incorporate arsenate groups into their DNA rather than phosphate groups.

If so, these remarkable bacteria may be evidence of how some sorts of bacteria flourished in extreme environments in the early Earth's oceans, or how alien lifeforms on other worlds might be able to use a different chemistry. NASA, which paid for the research, is understandably keen to emphasize that point.

Or maybe not. Notice the qualifiers? As often happens in science, media accounts tend to overstate the certainty of the finding and its implications. There are other possible explanations for the data produced by Felisa Wolfe-Simon and her team, and there has been sufficient heat generated over this that Science magazine has taken the rare step of making a current article available free to the public for a few weeks here.

Could be a lively discussion with the Mayor, and it certainly intrigues me as a high school science teacher, as this is something happening in our neck of the woods, and a topic of discussion in the popular culture. It's just the kind of thing that science teachers should be prepared to briefly discuss with students who are understandably intrigued by the fact it was found nearby, and that it might have a bearing on things like the origin of life either on Earth, or on outer space. It doesn't hurt that Wolfe-Simon sees the value of promoting her own research interests: her web site is a hoot.

And you know, it is fascinating to learn about the diversity of microbes and their adaptations to extreme environments. Wolfe-Simon's work is a logical extension of recent work that established the fact that microbes are involved in the cycling of arsenic in these soda lakes. You can read about that here.

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