Influence of Abiotic Factors in the Chemical Origin of Life: Biomorphs as a Study Model

New Insights on the Origin of Life: The Role of Silico-Carbonates of Ba (II) to Preserve DNA against Highly Intense UV Radiation

Understanding the origin of life on our planet has generated diverse theories. Currently, the theory is that life has a single origin; however, its starting point has not been defined. As evidenced, it is indispensable to unify the different theories to reach a single theory that would also allow linking the different areas of knowledge to finally understand the mechanism by which life originated on Earth. In this regard, aiming at contributing to the unification of the diverse theories on the origin of life, in this work, the hypothesis based on the condition that silica-carbonates of alkaline earth metals, called biomorphs, are the ones that could unify all the proposed theories on the origin of life is proposed. Aimed at evaluating if this hypothesis is viable, this work assessed whether biomorphs are able to protect the DNA from continuous UV radiation under two conditions that emulate the habitats that could have co-existed in the Precambrian and, after the radiation, evaluated the time during which DNA remained inside the biomorphs. Our results showed that biomorphs can protect the DNA for months after continuous UV exposure. It was also determined that biomorphs protect the DNA from external factors in different habitats, like normal atmospheric conditions and in aqueous environments. The obtained data allowed me to infer that biomorphs may be the gap that unifies the diverse proposed theories on the origin of life in our Planet.

Protection of the DNA from Selected Species of Five Kingdoms in Nature by Ba(II), Sr(II), and Ca(II) Silica-Carbonates: Implications about Biogenicity and Evolving from Prebiotic Chemistry to Biological Chemistry

The origin of life on Earth is associated with the Precambrian era, in which the existence of a large diversity of microbial fossils has been demonstrated. Notwithstanding, despite existing evidence of the emergence of life many unsolved questions remain. The first question could be as follows: Which was the inorganic structure that allowed isolation and conservation of the first biomolecules in the existing reduced conditions of the primigenial era? Minerals have been postulated as the ones in charge of protecting theses biomolecules against the external environment. There are calcium, barium, or strontium silica-carbonates, called biomorphs, which we propose as being one of the first inorganic structures in which biomolecules were protected from the external medium. Biomorphs are structures with different biological morphologies that are not formed by cells, but by nanocrystals; some of their morphologies resemble the microfossils found in Precambrian cherts. Even though biomorphs are unknown structures in the geological registry, their similarity with some biological forms, including some Apex fossils, could suggest them as the first "inorganic scaffold" where the first biomolecules became concentrated, conserved, aligned, and duplicated to give rise to the pioneering cell. However, it has not been documented whether biomorphs could have been the primary structures that conserved biomolecules in the Precambrian era. To attain a better understanding on whether biomorphs could have been the inorganic scaffold that existed in the primigenial Earth, the aim of this contribution is to synthesize calcium, barium, and strontium biomorphs in the presence of genomic DNA from organisms of the five kingdoms in conditions emulating the atmosphere of the Precambrian era and that CO₂ concentration in conditions emulating current atmospheric conditions. Our results showed, for the first time, the formation of the kerogen signal, which is a marker of biogenicity in fossils, in the biomorphs grown in the presence of DNA. We also found the DNA to be internalized into the structure of biomorphs.

Modification of Surfaces with Vaterite CaCO3 Particles

Former studies have demonstrated a strong interest toward the crystallization of CaCO3 polymorphs in solution. Nowadays, CaCO3 crystallization on solid surfaces is extensively being studied using biomolecules as substrates for the control of the growth aiming at various applications of CaCO3. Calcium carbonate exists in an amorphous state, as three anhydrous polymorphs (aragonite, calcite and vaterite), and as two hydrated polymorphs (monohydrocalcite and ikaite). The vaterite polymorph is considered as one of the most attractive forms due to its large surface area, biocompatibility, mesoporous nature, and other features. Based on physical or chemical immobilization approaches, vaterite can be grown directly on solid surfaces using various (bio)molecules, including synthetic polymers, biomacromolecules such as proteins and peptides, carbohydrates, fibers, extracellular matrix components, and even biological cells such as bacteria. Herein, the progress on the modification of solid surfaces by vaterite CaCO3 crystals is reviewed, focusing on main findings and the mechanism of vaterite growth initiated by various substances mentioned above, as well as the discussion of the applications of such modified surfaces.