Abiogenesis - Conceptual History - Complex Biological Molecules and Protocells

Complex Biological Molecules and Protocells

Sidney W. Fox also experimented with abiogenesis and the primordial soup theory producing a number of reports between 1964 and 1988. In one of his experiments, he allowed amino acids to dry out as if puddled in a warm, dry spot in prebiotic conditions. He found that, as they dried, the amino acids formed long, often cross-linked, thread-like, submicroscopic molecules now named "proteinoids".

In another experiment using a similar method to set suitable conditions for life to form, Fox collected volcanic material from a cinder cone in Hawaii. He discovered that the temperature was over 100 °C (212 °F) just 4 inches (100 mm) beneath the surface of the cinder cone, and suggested that this might have been the environment in which life was created—molecules could have formed and then been washed through the loose volcanic ash and into the sea. He placed lumps of lava over amino acids derived from methane, ammonia and water, sterilized all materials, and baked the lava over the amino acids for a few hours in a glass oven. A brown, sticky substance formed over the surface and when the lava was drenched in sterilized water a thick, brown liquid leached out. It turned out that the amino acids had combined to form proteinoids, and the proteinoids had combined to form small, cell-like spheres. Fox called these "microspheres", a name that subsequently was displaced by the more informative term protobionts. His protobionts were not cells, although they formed clumps and chains reminiscent of cyanobacteria. They contained no functional nucleic acids, but split asexually and formed within double membranes that had some attributes suggestive of cell membranes. Professor Colin S. Pittendrigh stated in December 1967 that "laboratories will be creating a living cell within ten years," a remark that reflected the typical contemporary levels of innocence of the complexity of cell structures.