Remember arsenic life? In 2010 NASA researchers thought they'd found evidence that certain bacteria could use arsenic in their DNA where all other forms of life on Earth use phosphate. Then it turned out their research was really flawed. Then it turned out they were wrong. In general, there was a to-do.

Fast forward to this month, when scientists from the Weizmann Institute of Science in Rehovot, Israel published a study in which they were trying to figure out how bacteria can tell the difference between phosphate and arsenate and "know" to prefer the phosphate. They used phosphate-collecting proteins from four different species of bacteria in their research, including the one that had been at the center of the arsenic life controversy. And along the way, they discovered a fun twist to that story.

This new study suggests that "arsenic life" bacteria is, indeed, able to survive in arsenate-heavy solutions where other bacteria fail. But, the Weizmann researchers say their data shows that success isn't due to a preference for arsenic, or even an ability to use it. Instead, "arsenic life" is probably just much, much, much, much better at collecting and using every tiny trace of phosphate it can get its metaphorical paws on.

The researchers looked at five types of phosphate-binding protein — which bind phosphate in a molecular pathway that brings it into the cells — from four species of bacteria. Two of the bacterial species were sensitive to arsenate and two were resistant to it. To test how effective these proteins were at discriminating between phosphate and arsenate, the researchers put them in solution with a set amount of phosphate and different concentrations of arsenate for 24 hours, and then checked which of the molecules the proteins would bind to.

Their threshold for when ‘discrimination’ broke down was when 50% of the proteins ended up bound to arsenate — indicating that the ability to discriminate had been overwhelmed. Even in solutions containing 500-fold more arsenate than phosphate, all five proteins were still able to preferentially bind phosphate. And one protein, from the Mono Lake bacterium, could do so at arsenate excesses of up to 4,500-fold over phosphate.

... The latest paper shows that the “arsenic monster” GFAJ-1 goes to a huge amount of effort, “even more than other life”, to avoid arsenate, says Wolfgang Nitschke from the Mediterranean Institute of Microbiology in Marseilles, France, who co-authored a commentary questioning the conclusion that GFAJ-1 could replace phosphate with arsenate.

Read the rest of the story at Nature News

Image: Mono Lake with Tufa Towers at Sunrise 16Oct2011., a Creative Commons Attribution (2.0) image from mikebaird's photostream

In early 2011, Felisa Wolfe-Simon published a scientific paper purporting to show evidence that bacteria from California's Mono Lake could, if pressed, live without the essential element phosphorous, and use arsenic, instead.

The story was wildly misconstrued in the press. (No, nobody ever found alien life happening naturally in Lake Mono.) And the evidence and methodology of Wolfe-Simon's research was roundly trounced, not just in academic journals, but also in blogs.

And that's all left Wolfe-Simon in a very weird position. She's certainly not the first scientist to publish a high-profile paper that other researchers tore to shreds. But, because the "arsenic life" story was so high-profile, she's now worried her career might be over. Is that fair? In Popular Science, Tom Clynes presents a nuanced profile of Felisa Wolfe-Simon that doesn't really answer that question definitively. Frankly, there probably isn't a really clear black/white answer out there. But Clynes does do a really good job of introducing us to Wolfe-Simon as a person, and her story exposes flaws in the peer-review process and the traditional avenues of scientific debate, indicts the media and PR professionals for creating the very sensational story that led to such a harsh response, and shows what can happen when a scientist is unprepared to deal with the public presentation of their own work.

In other words, this story is about lots of people making mistakes, including, but not limited to, Felisa Wolfe-Simon.

In June, Science reported that Wolfe-Simon had left Oremland’s USGS laboratory to look for a location with better molecular and genetic research facilities. “Actually,” Wolfe-Simon says, “I didn’t leave out of choice. Ron basically evicted me from the group. It was a political decision on his part that I don’t understand, and I didn’t see it coming.” Although she received a NASA fellowship in 2010 that provides support through 2013, she is still seeking a new home for her work.

I find it hard not to feel sympathy for her. In a matter of weeks she was catapulted to fame, then singled out and assaulted with professional and personal criticism, some of which resulted from missteps beyond her control. Wolfe-Simon is an early-career researcher in a field dominated by older men. Few scientists, no matter how established, would have the skills to navigate the situation that she found herself in. What made the level of criticism so extraordinary is that the paper, in itself, is not so flawed that it should not have been published. The argument was compelling, the conclusions were measured, the data was thorough, and the paper made it through the same peer-review process as other articles in Science.

It will take a few years to better answer the questions surrounding GFAJ-1. In the meantime, Benner—who says he would be “more than astonished” if arsenic replaces phosphorus in any genetically relevant molecule in GFAJ-1—says Wolfe-Simon’s hypothesis is ultimately useful if it motivates people to look in new places and ask bigger questions.

Wolfe-Simon says the paper’s publicity attracted new collaborators who she wouldn’t have otherwise met, some of whom are already analyzing GFAJ-1. And her fame has played out in surprising ways. Recently, her husband, Jonathan, an engineer, was speaking with a colleague who asked if he happened to be married to Felisa Wolfe-Simon. When he said yes, the colleague said, “My seven-year-old daughter dressed up as Felisa for her school’s science day!” The girl wore a sun hat, with her pants rolled up and flip-flops on her feet, dressed for a day wading the waters of Mono Lake in search of bacteria.