Coffee Spoons (Part One)

If you’re anything like me, you responded to recent news articles on the global coffee and chocolate shortage with a wail.  My own dismayed “Nooooo!” was just about fit for a Star Wars movie.  I love coffee and chocolate, especially together: their rich color; their smoky, bitter, very lightly sweetened tastes; the caffeine… the caffeine.

I imagine chocolate coming from Europe and coffee coming from Seattle, but of course it wasn’t always that way. Though chocolate has a venerable place in European culture, it got there just five hundred years ago in the Columbian exchange; and any coffee aficionado worth their grounds can tell you that both Arabica and robusta beans are native to Ethiopia.

When plants full of the same psychoactive compound start turning up across oceans, you start to wonder when they evolved that compound, and why.  And the plot thickens: caffeine is also found in tea, of course, not to mention the kola nut from Nigeria, and the yerba mate holly, guarana, and guayusa from the Amazon.  If you’ve been keeping score, that’s three continents’ worth of caffeinated delights, and those are only the plants that humans consume.

Caffeine is what’s known among plant biologists as a specialized metabolite. It isn’t absolutely needed to keep the plant alive, but improves its chances a little; human addicts may feel the same effect. Plants synthesize caffeine mostly in seeds and nascent leaves, where the compound paralyzes pests that try and eat these vulnerable tissues. The caffeine molecule looks a great deal like the universally-used nucleotide (DNA component) adenosine, and it does its work both in the human brain and the insect physiology by impersonating adenosine’s energy-carrying cousin ATP.

Caffeine biosynthesis is a fairly simple pathway. Once you have adenosine around, which every organism known to science does, it’s just a matter of cutting one or two bonds and switching out a methyl group or two to generate caffeine. It’s the kind of metabolite that, if gene products were patents, would make you smack your forehead and shout, “Why didn’t I think of that first?!” Therefore it’s not surprising that caffeine biosynthesis has evolved at least twice in plants: they have plenty of enzymes that specialize in cutting bonds and transferring methyls, it was only a matter of time and slightly altered specificity.  In fact, these researchers say, based on protein sequence analysis, that the same cutting-and-switching enzymes that held down one job in the plant left for the new caffeine-synthesis job several times in different plant lineages. So, although tea, coffee, and chocolate have the same delectable effects on our brains, they came to these effects independently.

Knowing this stuff won’t help us solve the caffeine shortage that is sure to give many of us metaphorical (and also withdrawal-induced) headaches over the next harvest season. Besides a sudden reversal of global climate change, it’s not clear what can do that. But at least we know that this precious metabolite is a feature of many plants, probably some we haven’t found yet.  And if all else fails, there’s always straight-up pharmacological synthesis!


How we spin a scientific story

It’s a common metaphor among scientists that to report your data is to tell your audience a story. No one gets excited about finding the answer to a question they aren’t invested in, which only makes sense; to be excited about results, you have to know where they fit into the field of previous knowledge and what will happen next.  And narrative is a great way to convey all that, to make an audience interested in a problem

That’s why the first ten minutes of any academic presentation are devoted to making a case for why the question is interesting, worth the scientist’s time and the audience’s attention.  Call it setting the stage, beginning the story, catching the audience up to where the excitement begins. The research question makes the dramatic conflict; if a presentation is really good, then the hero is clever and thorough in their approach to answering the question, but not self-aggrandizing (such are the hazards of telling a story about yourself). Once the question is answered, in full or in part, the denouement must remind the audience why they’re supposed to care; how will we all live happily ever after, or else what are the prospects for a sequel? (Applications for funding, though in theory they have only the very beginning of the story, are especially glowing when they pitch the sequels).

As in fiction, in a good scientific story the hero is relatable; knowing only what they have been told, the audience can see why the approaches the researcher took are sensible, can imagine taking such approaches themselves. This is what makes it tricky for scientists to tell nonscientists about their research. You can always assume that a roomful of cell biologists will agree that cell cycle control is an interesting topic. A roomful of normal people will want to know the point.  That’s why the world is full of publications like Discover and Scientific American, which make it their business to communicate why the eggheads are so excited.

Popular science writing tends to slant toward the novel, the gross, and the health-related: topics that are intrinsically interesting. When it is bad, it is very, very bad (here’s a great sendup of the crappy pop-sci story).  But when it is good, it is splendid.

This blog will be about how scientists and writers communicate science: to one another and the public.  What’s compelling?  What isn’t?  And what genuinely cool answers are out there waiting to be shared?