Space Dinos! Prebiotic Chemistry Meets Paleozoic Commentary

Source: Columbia Giving

When I open Google News, I usually expect to see trade agreements, protests, car shows, or sports quotes. But, when I read a title like Dinosaurs from Space! (Smithsonian), or Do Intelligent Dinosaurs Really Rule Alien Worlds? (Discovery),  I'm admittedly drawn in.

Ready for the real shocker? It's a paper published in JACS! No joke - here's the ACS presser. Bonus: the paper's written by a well-respected research lion - Ron Breslow, long a veteran of Columbia's chemistry department (Aside: I couldn't recall if ChemBark had seen Breslow's professorial "portrait," (right), courtesy of Columbia's University Giving Office).

The paper, a Perspective, reads fairly well: Breslow muses about the origin of homochirality on the early Earth, a subject near and dear to researchers such as Robert Shapiro, Albert Eschenmoser, Jack Szostak - and #1 on Philip Ball's list of chemical "grand challenges." Breslow recalls that scientists measured small enantiomeric excesses in amino acids, from 2-15% of the S (also called "L-") form, found in several meteorites that fell to Earth in the last 50 years. He then demonstrates, using a clever mix of solvation energies and autocatalytic reactions, some possible prebiotic setups leading to enrichment of single-enantiomer sugars and amino acids. 

Sound good? Well, it's all fine up until the closing paragraph - again, no exaggeration on my part:

"An implication of this work is that elsewhere in the universe there could exist life forms based on D amino acids and L sugars...Such life forms could even be advanced versions of dinosaurs,  if mammals did not have the good fortune to have the dinosaurs wiped out by an asteroidal collision, as on Earth. We would be better off not meeting them."

Artist's Representation: Life Elsewhere
Source: fanpop.com

I'm actually both horribly amused, and somewhat embarrassed by that conclusion. It's playful and exciting, yes, but, as others have pointed out, it sounds suspiciously like bait to draw sensationalist reviews and lure more casual readers. 

Well, two can play at this game! Without further ado, I'd like to offer a few novel O.O.L. speculations of my own: 
- On "Earth 2," in a far-off galaxy, a preference for body hair, muscles, and heavy brows favored Neanderthals over modern humans. 

- Life on distant planets proven to be highly evolved amoebas, who had the good fortune never to form into any multi-cellular critters.

D-amino acids + L sugars = Luck Dragons?
Source: Kristen Lamb

- In the land of Fantasia, a young boy named Atreyu must find the Nothing killing his world (wait, no, that's the Never Ending Story...).


- On Planet 2G, slightly different rules of gravity and lack of water, combined with a preponderance of slightly chiral amino acids led to...really beautiful crystal gardens, but not much life. (sorry, everyone!)

Super Tasters and Smells in Space

Back in Junior High School¹, my first chemistry teacher ran a fascinating experiment. He dabbed a small amount of dilute capsaicin on the back of a piece of bread, and handed it to each class member. Of course, most of us felt the burn, but not one girl - she was genetically insensitive to capsaicin’s painful effects.

The science of taste and smell fascinate me, since they not only underlie many of our daily chemical interactions, but provide clear survival benefit to the species. The ability to smell smoke or taste bitter alkaloids might allow you to detect fires or avoid poisonous foods. In 2006, Glindemann and coworkers reported the source of the “iron smell,” the dark, musky odor produced when you touch coins or metal handles. His group traced the smell back not to compounds in the metal itself, but to chemical changes of body oils spontaneously produced upon contact (one of the stronger odorants, 1-octen-3-one, shown at left). The chemists theorize that the ability to smell these metallic odors traces far back in our evolutionary history, to when “blood smell” helped early human hunters track their prey through the woods.

Well, if smells are so critical, pity the poor astronauts. Space missions show that after a few days in weightless conditions, astronauts can no longer smell or taste their food properly, and begin to crave hot spices and bold flavors. NPR reporter Joe Palca explored this condition, called “stuffy-nose effect” or the “Charlie Brown syndrome” (due to the enlarged appearance of your head in space when your facial tissues swell with fluid, an effect of lessened gravity).

Charlie Brown and Snoopy
Source: The Telegraph | Charles M. Schultz

Want to help test the phenomenon? A joint Cornell /U.Hawaii study is now recruiting applicants. You’ll live in a simulated Mars mission habitat in Hawaii, where researchers will test food preparation with limited ingredients. They’ll induce the “stuffy-nose effect” with specialized beds that keep the head slightly lower than the rest of the body, and test various spices and food replacements for space palatability.

Maybe these scientists shouldn’t worry about smell deprivation, and just recruit a bunch of supertasters. These genetically gifted sense superstars possess more taste buds (papillae) on the tongue surface than others, which can be observed by simply staining the tongue blue and looking in a mirror. Supertasters report heightened sensitivity to subtle changes in food or drink, and naturally cluster in occupations such as chefs or sommeliers.

Count the taste buds!
Source: NPR | Maggie Starbard

The physiological prowess of supertasters was first noted in back-to-back PNAS papers in the 1930s. Amazingly, the trend started when two chemists – Drs. Fox and Noller, of DuPont – exhibited markedly different reactions to the taste of phenyl thiocarbamide dust in the air. The two scientists then prepared several analogues of the parent thiocarbamide, and ran around asking people to taste them!

The second paper, from geneticist Albert Blakeslee at the Carnegie Institution in Cold Spring Harbor, tested the effect of dilution on the taste sensations of a few hundred people of different racial and ethnic backgrounds. On the menu, in addition to the DuPont compound, were hydrochloric acid, picric acid, salt, and saccharine. Blakeslee found that there were distinct groups of people who could taste at certain thresholds, the “tasters” and the “non-tasters.” Further research, as explained by food scientist John Hayes in a broadcast of the WNPR Colin McEnroe show a few nights back, has shown that humans actually fit into three distinct categories: “non-tasters,” “medium-tasters,” and “supertasters.” The updated test involves placing a small crystal of propylthiouracil (PTU, see above) on the tongue and recording the intensity of the each person’s reaction; supertasters recoil at the bitterness, while “non-tasters” barely notice a difference.

1.No, it wasn’t ‘middle school’ back then, and yes, I walked uphill both ways, in the snow, carrying my books.