David Deamer is a Research Professor in the Department of Biomolecular Engineering and Department of Chemistry and Biochemistry at the University of California, Santa Cruz. His undergraduate BSc degree was in Chemistry, at Duke University, Durham NC (1961) and his PhD in Physiological Chemistry from the Ohio State University School of Medicine (1965). Following post-doctoral research at UC Berkeley, he joined the faculty at UC Davis in 1967. In 1994 he moved his laboratory to UC Santa Cruz.
Prof. Deamer's research interest is the origin of cellular life on the Earth nearly four billion years ago. This work involves studies of meteorites that contain organic carbon compounds, and self-assembly of complex lipid-protein structures that exhibit some of the properties of life. A second research area concerns DNA transport through nanoscopic pores in membranes and developing a nanopore-based instrument that can analyse nucleic acids as individual molecules.
First life, and next life: the origins and synthesis of living cells
Mary Shelley's classic tale describes how Dr. Victor Frankenstein assembled a living creature from body parts. Several laboratories are now attempting to perform a reconstitution of life eerily similar to Frankenstein's dream, but on a microscopic scale. There is even a name for such science: synthetic biology. Synthetic life, defined as life that did not arise from preexisting life, spontaneously emerged more than three billion years ago, when the first living cells appeared in a sterile environment. Although the conditions that fostered primitive cellular life are still largely unconstrained, we can be reasonably confident that liquid water was required, together with a source of organic compounds and energy to drive polymerisation reactions. There must also have been a process by which the compounds were sufficiently concentrated to undergo physical and chemical interactions.
The self-assembled structures that resulted under these conditions are referred to as protocells, in that they exhibit certain properties of living cells and represent evolutionary steps toward the first forms of cellular life. Driven by the forces of natural selection, those first cells evolved into the biosphere we inhabit today. The complexity of a living system is wonderfully intricate, and there is still much to learn about simpler versions of life that must have been precursors to contemporary organisms. At some point it seems likely that we will know enough to try to fabricate a living system of molecules in the laboratory, and from this effort learn more about the origin of life. For instance, simple protocells have been produced by encapsulating enzymes and nucleic acids in cell-sized lipid vesicles. RNA and DNA have been enzymatically synthesized in such microenvironments, and encapsulated ribosomes can translate genes embedded in messenger RNA into specific proteins.
The most complex protocell so far incorporates a synthetic DNA molecule with several genes. The genes are enzymatically transcribed to messenger RNA, then expressed by ribosomes as proteins. This achievement is astonishing, but there is still far to go before a living cell can be assembled from a parts list. The reason is that well over a hundred genes must be expressed even in the simplest version of a complete artificial cell, half of these simply to assemble ribosomes. In my talk I will outline several approaches to synthetic life, and describe how we can learn about the origin of life by attempting to reassemble cells in the laboratory.