Evidence of Catalytic Activities from and Inside Meteorites. Did They Contribute to the Early Life by Increasing Molecular Complexity of a “Primitive Soup”?

The origin and dispersion of Life in the Universe is a long debated scientific and philosophical issue and, in this context, much work has been devoted to the analysis of different types of meteorites to reveal in them the signature or the remnants of possible forms of life. We have developed and applied an innovative approach (Geraci et al. 2007), aimed at revealing not life itself, or organic components, but the ability of meteorites to perform reactions operative in present-day life. To this aim we have carried out experiments on several fragments of iperstenic chondrites, looking for conditions permitting them to express catalytic activity. We found that, in suitable environments, components of the meteorite fragments are able to catalyze inorganic and organic reactions. Samples initially used were different specimens from two iperstenic chondrite swarms (Mòcs and Holbrook) fallen, respectively, in 1882 in Transylvania and in 1912 in the desert of Arizona, to minimize the possibility that the observed properties depended on the conservation conditions. Furthermore, similar results were obtained also using fragments of other iperstenic chondrites fallen on Earth in areas with different climates and in different years, each with a different background. Particularly, we report here that fragments of iperstenic chondrite perform, in specific conditions (Geraci et al. 2007), glycosidase activity on α- and β-glycoside bonds and esterase activity both in water and in organic solvents. Those activities have been revealed also on substrates commonly employed in biomolecular laboratory analyses. In addition, meteorite fragments produce complex metal-organic structures whose material is endowed of physical and chemical properties not present in the starting meteorite sample, such as an amazing magnetism and ability to absorb light. Those structures appear hollow, semi-transparent and pigmented orange-red, from pale to deep ruby. Their exterior is made of repetitive micro–nano units, having one side flat, laying on a thin organic layer, and the other brush-like. They appear only in aerobic conditions, indicating that redox reactions have a role in their autopoietic formation. Moreover, when damaged, they are capable to regenerate/repair themselves upon suitable external stimulation. Preliminary analytical results on the complexity of their organic and inorganic areas and on their repetitive polymeric structures demonstrate the ability of their growth processes to selectively accumulate and use externally provided biomolecules, some of which appear even chemically modified and in new molecular combinations. The results so far obtained do not prove or exclude the possibility that those structures, having a complex chemistry, might be examples of proto-metabolic reactions occurred in a pre-biotic context. However, they are certainly the result of a number of coordinated activities and only some of them can be attributed to the meteorite components. The data presented here lend support to the hypothesis that these “activities” might have participated to increase the molecular complexity of an initial “primitive soup” contributing to trigger the emergence of life.