Cell Origin Research Is in Hot Water


Researchers have tried for decades to replicate the conditions and compounds they think were necessary for the first living cell to evolve. Their experimental failures have collectively sent the clear message that such an event is extremely unlikely or even impossible. Even some of the most basic chemicals found in all cells require already-intact cells to make and maintain more.

Still, many scientists continue to search for an origin of life by strictly natural means. In a recent study published in Astrobiology, Marcello Guzman, a postdoctoral fellow at the School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences at Harvard University, focused on shallow marine hydrothermal vents as possible ancient environments that hypothetically could have spawned life from non-life.1

Guzman took cues from some of the lowermost fossil structures in sedimentary rocks, called stromatolites, even though considerable debate surrounds them. Many stromatolites are dome-topped rocky features that form from debris deposited by a cyanobacterial colony, but it is not clear whether other stromatolite-like structures were caused by cyanobacteria, or more simply by accretion of debris from ancient hydrothermal vents.

Living stromatolite colonies in Shark Bay, Australia, consist of complicated photosynthetic cells, which look exactly like well-preserved cells found in some fossil stromatolites. Each of these cells has more primary biological information than those of standard bacteria. They not only carry the instructions to manufacture the cellular machinery that converts and utilizes chemical energy, but they also have everything they need to capture and store raw sunlight energy―as well as produce and secrete a sticky substance to which their cells adhere in order to form colonies.

Not even the most advanced technology created by humans can capture and store energy like the cyanobacteria that formed many of the fossil stromatolites. And if humans are the best technicians in all creation and yet cannot replicate these abilities, then it would seem counterintuitive to propose that anything like these cells could have been the first to have emerged from raw chemicals.2

Guzman suspected that some ancient cell-like system was an integral step toward the first cell. This “prebiotic metabolism” must have operated “without enzymes playing a role,” presumably because enzymes are molecule-sized machines that are too rich in information to have arrived by any time-and-chance process alone. He told Astrobiology Magazine that “maybe metabolites in the environment allowed the first cells to have the chemistry they needed to run. Maybe in the first cell, a mineral catalyzed certain reactions.”1

However, experiments involving prefabricated organic compounds that were injected into deep hydrothermal vent environments have totally failed.3 The primary origin-of-life researcher involved with these experiments stated in 2006 that “the reason this is significant is that it has been proposed that clay promotes interesting chemical reactions relating to the origin of life. However, in our experiments, the organic compounds became so strongly held to the clay particles that they could not undergo any further chemical reactions.”4

So, since deep vents won’t work, Guzman is testing the possibility of shallow vents. He used ultraviolet light shining on a semiconducting compound called zinc-sulfide, while it was in the presence of concentrated and prefabricated organic compounds, to produce some chemical reactions that are similar to what algae perform with their enzymes. He and study co-author Scot Martin were able to coax very small amounts of a carbon-containing compound called pyruvate, plus other chemicals, from the sugar lactate. Pyruvate is a small but key compound involved in photosynthetic reactions.

But this result is irrelevant to the origin of enzymes or the coordinated multi-enzyme cascade systems that precisely manipulate these smaller chemicals within a living cell. Far from being a breakthrough in origin of life research, the claim that this finding is even a relevant step toward the construction of a cell—let alone a photosynthetic cell—is similar to claiming that a lab experiment that produces a gooey mixture including some plastic provides evidence for the natural formation of laptop computers.

Astrobiology Magazine very accurately reported that “scientists still don’t know exactly what chemical elements were needed for the origin of life on Earth.”1 But those few scientists who are even willing to consider the problem of the origin of information are even more frustrated.5 As long as they seek for life’s source solely in nature, their frustrations will only mount.

References

  1. Herath, A. K. Shallow Origins. Astrobiology Magazine news release, December 21, 2009, reporting research published in Guzman, M. I. and S. T. Martin. 2009. Prebiotic Metabolism: Production by Mineral Photoelectrochemistry of α-Ketocarboxylic Acids in the Reductive Tricarboxylic Acid Cycle. Astrobiology. 9 (9): 833-842.
  2. Thomas, B. The Finest Solar Technology Doesn’t Come from a Lab. ICR News. Posted on icr.org October 7, 2008, accessed January 6, 2010.
  3. Deamer, D. et al. 2006. Self-assembly processes in the prebiotic environment. Philosophical Transactions of the Royal Society B: Biological Sciences. 361 (1474): 1809-1818.
  4. Life on Earth ‘unlikely to have emerged in volcanic springs.’ The Royal Society press release, February 13, 2006.
  5. Thomas, B. 2009. Dawkins’ Latest Book: The Greatest Lie on Earth. ICR News. Posted on icr.org September 23, 2009, accessed January 4, 2010.

Image credit: Paul Harrison

* Mr. Thomas is Science Writer at the Institute for Creation Research.

Article posted on January 13, 2010.