At Home in 'Rocco's Lab'
Virginia Woolf once famously said, "A woman must have money and a room of her own if she is to write fiction." It might as accurately be said that a scientist must have funding and a lab of her/his own. In the summer of 2004 the nearly 50 Carl Sagan Center (CSC) scientists of the SETI Institute moved to a new facility with three vacant laboratory spaces and instantly acquired entire new vistas of research. One of those laboratories has been fully outfitted and operational for nearly six months now. That has made all the difference to Dr. Rocco Mancinelli and the other astrobiologists who analyze their samples in the Microbial Ecology and Molecular Microbiology Laboratory--Lab 2 or simply 'Rocco's lab" to friends.
Astrobiologists, those cross disciplinary scientists dedicated to investigating the broad question of life in the universe, often study extremophiles, organisms that live at the edges of what life is known to tolerate. Bubbling acidic hotsprings, deep ocean blacksmokers, and deep dark caves are the sources of some researchers' extremophiles-those that love high temperatures, great pressures or live without light, but Dr. Mancinelli gets his microbes wherever there is lots of salt. Halophiles are salt lovers and thrive where salt abounds in concentrations that would kill most ordinary organisms. Halophiles are incredibly robust creatures.
Mancinelli has flown them in the vacuum and freezing temperatures of space, exposed to intense radiation, and most of them returned alive and well. He regularly collects them from salty mountain lakes high in the Bolivian Andes, but he can also find them right next door in the San Francisco Bay. In fact, halophiles are found in all waters with high salt content, that is, from 15% up to the saturation point. There are halophiles in all three known branches of living systems (domains of life), that is, the Archea, organisms having characteristics of both the Bacteria and the Archaea, Bacteria, the most prevalent organisms on earth and the Eukaryotes, which include the most complex organisms on earth including you and me. Because these halophilic microbes are so ubiquitous and so robust, they are great candidates for the kind of organism that might once have lived or possibly even still survives, on Mars.
Once samples arrive in the Halophile Lab, they are studied to see what they contain. Lake or seawater samples are usually stored at 4? in the refrigerator before analyses begin and then a bit is "innoculated" into a flask of halobroth, a rich salty solution that encourages the organisms to thrive and multiply. A bit of this resulting mixture is then "streaked" onto a set of Petri dishes or "plated" with more halobroth, and colonies of organisms often result. In this way, often simply through visual inspection, a single organism can be identified, reintroduced to a halobroth flask, cultured and plated and ultimately isolated for further study. Once a single organism is isolated, the real fun begins.
Some of the halophilic organisms are incubated at a range of temperatures, such as 4?, 12?, ambient and 37? C to see how they survive and grow. Mostly, they do quite well, growing more slowly at the low temperatures and growing more rapidly at the warm temperatures. Some of them are irradiated with ultra violet (UV) light in the controlled laboratory setting and then carefully studied to see how they are affected and to gain clues to their survival strategies, whether it be from the salt itself or from some clever genetic mechanism. Some of them are really put through their paces with freeze and thaw cycles. Most of them still manage to survive even this sort of radical environmental change. Again, they are carefully studied to see just what constitutes the survival mechanism.
While Rocco's Lab is not his first, by any means, all these carefully controlled studies are greatly facilitated by having an on-site laboratory dedicated to the study of microbial ecology and under the management of a single researcher. The team takes strict care of both the organisms and the lab itself. Having a lab dedicated to specific aspects of microbial ecological research has greatly advanced the team's ability to make progress. In fact, Dr. Mancinelli and his team are about to embark on a next-steps series of experiments to complement the characterization studies of the halophiles: studies of the nitrogen cycle, how nitrogen is fixed and released in soils in dry, high altitude Mars analogues. Mancinelli believes that nitrogen, a critical element for biologic systems, may be a key bio-marker. Now that he has a lab of his own, he might just find out.
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