Archive for January, 2012

Arsenic: Still Poisonous

In December 2010, NASA announced a momentous discovery: bacteria that could use arsenic instead of phosphorus in its genetic material, a direct substitution in the DNA. This would be a huge deal if true, rewriting much of what we know about basic biology. People were hoping for alien life forms, but this would be nearly as important, if much less glitzy.

We already knew that bacteria could use arsenic in their metabolism; the ability to use it in their DNA would mean that they didn’t need phosphorus at all. The most abundant elements in living organisms are: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. All are believed to be essential for life. Substituting arsenic for phosphorus would alter that basic principle.

Scientists were immediately skeptical of the claims of Dr. Wolfe-Simon and her colleagues. Many insightful critiques were published online, but the authors of the original paper stated that they would only answer peer-reviewed rebuttals. Our own Dr. Athena Andreatis discussed the arsenic findings on her blog, and for Science in My Fiction.

Such a tremendous claim requires immaculate science and immaculate reporting, and neither were apparent.

In June 2011, the original paper finally saw print in Science (it had been available online since December). The reason for the delay: eight additional peer-reviewed technical comments on the original paper, and a response to those comments by the original authors.

I read all of them carefully with the intent of writing a summary to accompany my earlier essays about the arsenic bacteria, but never did. The short version of what I would have said: The eight comments pointed out several errors in methods and analysis. Some of the most major problems were described by several of the comments. I’m not the right kind of biologist to appreciate the nuances of molecular technique, but these descriptions of failings in the research were convincing.

Dr. Wolfe-Simon’s response boiled down to, “We did so do it right.” There wasn’t a substantive response to any of the problems raised.

The story isn’t over, but perhaps close. Dr. Rosie Redfield, one of the most outspoken critics of the original study and author of one of the Science comments, has tried to replicate the arsenic study with stricter methods and failed. Dr. Redfield and her colleagues found no arsenic in any of the bacterial DNA.

The original study appears to be a case of how not to do science. Based on interviews, Dr. Wolfe-Simon and her collaborators set out to demonstrate that this particular bacterium could substitute arsenic for phosphorus, and did not consider alternative scenarios or design methods that might clearly disprove their hypothesis. Their results were rushed into public without adequate peer review, but with much fanfare from NASA.

But since then, science has proceeded exactly as it should. Other scientists have raised issues in clear, technical fashion, and have tried to replicate these controversial results with more appropriate methods.

Although the key bits are or will be peer reviewed, much of the discussion has occurred openly on the internet, at least among the critics. None of the authors on the original paper have spoken up publicly, to the best of my knowledge, and have only responded to the comments that appeared in Science.

This has been a fascinating story to follow, but for the way the research was presented and followed up on than for the findings themselves. I try to end these articles with some consideration of story ideas. Here, I think the story comes from the people involved, rather than the science itself. (As, arguably, all the best science fiction does.) The discovery could have been anything, but the misinterpretation, critique and defense are what make it so interesting.

Edit (1 Feb. 2012): Dr. Redfield has now posted her mansucript on Arxiv for public comment. I have not read it yet, but wanted to let you know.

Soylent Green for dinner?

Medicine Drug Pills on PlateI find that there are few things that are more comforting than a tasty home-cooked meal. But cooking can take a fair amount of my time and energy, and requires that all the necessary ingredients on hand. Sometimes when I’m busy or tired or just feeling lazy, I wish there was a box of “people chow” in my cupboard that would make well-balanced and tasty meal, or perhaps a pill that could substitute for a satisfying dinner.

It’s not surprising that in the late 19th and early 20th century, when food preparation was much more labor intensive and time consuming than it is today, that writers who imagined scientifically advanced utopian societies of the future frequently described “instant” food that required no cooking.

The idea was common enough for writer Anna Bowman Dodd to satirize it in her 1887 novella The Republic of the Future, or, Socialism a reality:

The food is sent to us by electricity through the culinary conduits. Every thing is blown to us in a few minutes’ time, if it be necessary, if the food is to be eaten hot. If the food be cereals or condensed meats, it is sent by pneumatic express, done up in bottles or in pellets. All such food is carried about in one’s pocket. We take our food as we drink water, wherever we may happen to be, when it’s handy and when we need it.

Thus women were freed from the drudgery of the kitchen. Or as Dodd put it:

The perfecting of the woman movement was retarded for hundreds of years, as you know, doubtless, by the slavish desire of women to please their husbands by dressing and cooking to suit them. When the last pie was was made into the first pellet, woman’s true freedom began.

Dodd made it sound as if this would be a bad thing. But many thought that scientifically developed food substitutes would a positive development. At least in the first half of the 20th century, there were regular articles in the popular press about the “dream” of creating a meal in pill form.

And, of course, the pulp science fiction writers incorporated the idea into their stories.

By the way, have you folks eaten?”
“Not in a week,” said Karl.
“Von Sternberger’s food tablets,” informed the girl.
Carruthers nodded. His deep-set eyes regarded them appraisingly. “Any ill effects?”
“None whatever,” spoke Danzig. “Neither of us have the slightest craving for food.”
~ “Prisoners on the Electron” by Robert H. Leitfred (1930)

Sounds convenient, right? But here we are in the first part of the 21st century and most of us eat food that isn’t too far different from what people were eating a century ago.

So why don’t we have the equivalent of “Von Sternberger’s food tablets”? It turns out there are a number of reasons.

For one, we humans normally eat a wide variety of foods – a much wider variety than most other primates. A number of studies have shown that the diversity of foods we eat reflects the quality of our diet. Of course, that association is likely due at least in part to the link between poverty and a less diverse diet. Perhaps the lack of variety wouldn’t be a problem if scientists developed a food that met all human dietary requirements. It turns out not to be that simple.

We don’t actually yet know all the components that would make up an ideal human diet. For example, there are many compounds produced by plants – phytochemicals – that are thought to have anti-oxidant and other physiological properties. We are still learning what these compounds are and how they affect the human body, despite the bold claims of the dietary supplement sellers.

Another problem is humans have trouble eating the same food for every meal. Just imagine: there are 9 calories in one gram of fat, the most calorie-dense nutrient. That means you would need to eat a half pound of pure fat to get the 2000 calories burned daily by the average adult woman.  That’s a bare minimum, since balanced diets need to include less calorie-dense  components like proteins, carbohydrates and fiber.  While it’s not at all difficult to eat a pound (or more) of a tasty variety of foods per day, it’s harder to imagine happily swallowing a half pound of pills or eating a couple of pounds of not-particularly-tasty food pellets on a daily basis.

It’s not like people haven’t tried. A Canadian fellow named Adam Scott tried eating “monkey chow” for a week. At least in theory that diet should serve the nutritional requirements of most primates, including humans. The result? Scott lost weight, was tired and had serious cravings. While a diet of nutritious pellets might work as an alternative to Weight Watchers, it wouldn’t a very good replacement for human food. More seriously, even people who are malnourished have trouble eating enough food when the prescribed therapeutic diet is too monotonous.

And even if there is variety in our diet, food needs to taste good for humans to be healthy in both mind and body. For example, NASA has found that the “psychological well being” of astronauts depends at least in part on providing food that is tasty and has a “pleasant mouthfeel” . Because of that, NASA has moved away from the unappetizing food pastes and powders used to sustain astronauts on the Mercury missions, and worked on developing foods that the astronauts actually enjoy eating.

Naturally, science fiction has reflected many of those limitations.  In more recent SF stories, it’s more likely for mass-produced rations to be provided starving masses on resource-depleted and overpopulated Earth than to be eaten by the scientific or social elites.

All the TV shows have morale-builder commercials telling us how important our work is, how the whole world depends on us for food. It’s all true. They don’t have to keep reminding us. If we didn’t do what we do there would be hunger in Texas and kwashiorkor among the babies in Oregon. We all know that. We contribute five trillion calories a day to the world’s diet, half the protein ration for about a fifth of the global population. It all comes out of the yeasts and bacteria we grow off the Wyoming shale oil, along with parts of Utah and Colorado. The world needs that food.
~ Gateway by Frederik Pohl (1977)

Living on such food produced for basic sustenance, rather than for optimal health or pleasure, is a pretty bleak vision of the future.

Of course not all science fictional food is so unappetizing. In the resource-rich Star Trek universe, almost everyone can dine well on delicious synthetic food produced by replicators if they don’t want to cook for themselves.

Having access to a variety of food that tastes good, is nutritious and is available at the push of a button – that’s the future I’m hoping for.

Further reading:

• Paleo-Future’s “Meal in a pill” archives.

• Future Food section of David Szondy’s Tales of Future Past.

• NASA’s Space Food Fact Sheets and their Space Food and Nutrition site for students and educators.

• Cooper et al. “Developing the NASA Food System for Long-Duration Missions” J. Food Sci. 76(2):R40-R48 (2011) doi: 10.1111/j.1750-3841.2010.01982.x

Photo by on Flickr

Special Relativity for Dummies, I mean writers

So, practically everyone knows thanks to Albert Einstein that on a starship traveling close to the speed of light time will pass more slowly than in the rest of the universe, though it does seem that not everyone understands how that works.  For example, I recall reading a passage in The Andalite Chronicles where the narrator explained that they were traveling to earth at a sub-light speed that would take them about three days because if they went at maximum burn they might make it in a few hours but that would be years on earth.  That’s just wrong, relativity slows down time onboard the ship, it doesn’t speed up time outside or anything.
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All Aboard The Science Bandwagon

The crime rate may be down, but there are still plenty of villains to catch. Fortunately, science is on the case. That’s true in real life, where physicists devise more accurate ways to interpret blood spatter, and mathematicians analyze the patterns in gang violence to help solve old crimes and suppress future criminal activity. And it’s true on television, where forensic science has developed a vast and squeeing fandom.

Predictably, that fandom overlaps speculative fiction fandom quite a bit, but sadly, television science appears to have eclipsed science in sci-fi altogether. While it’s wonderful that scientists and Hollywood are forging new alliances for the sake of conjuring realism and as a canny method of reminding the masses that science is relevant to their interests, it’s disheartening to watch literature surrender that influence one sparkly vampire at a time.

No, it’s worse than disheartening. It’s uninteresting. And it’s unhealthy for speculative fiction to eschew – even disdain – science. Reading science-less sci-fi is like eating a junk food diet. How can the genre with science in its name be taken seriously if it’s about as intellectually nutritive as a Twinkie? Was it inevitable that television would eventually surpass literature as inspiration as well as entertainment?

Wonder of wonders, TV viewers like a little science in their fiction! Given the overlap between television audiences and people who read books, it’s probably safe to assume that readers also like a little science in their fiction. We should get back on that bandwagon.

Welcome to the future – what’s the date?

Or to 2012, at least. Changing the numbers on the calendar often prompts me to think about calendars, and I’m not the only one. This year even more so than usual, what with all the Mayan calendar hype, and a proposed calendar reform in the news.

What’s wrong with what we’ve got, and why are calendars so complicated anyway?

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