TP21
The session deals with three central "C's" relevant in discussions about living-matter origination and development on the Earth and other celestial objects: Concepts, Conditions and Cofactors.
All these approaches are dealing with transitions from non-living to living-matter and are integrating different technologies to shed some novel and interesting perspectives on one of the most puzzling unanswered questions of our science.
Session assets
Discussion on Slack
Oral and Poster presentations and abstracts
Understanding the origin of life (OoL) remains one of the most challenging challenges today with many scientific questions still unanswered. The complexity of the problem of the origin of life has spawned a large number of possible evolutionary scenarios. Their number, however, can be dramatically reduced by the simultaneous consideration of various bioenergetic, physical, and geological constraints. It is a widely accepted hypothesis that life originated from inanimate matter, being somehow a synthetic product of molecular organic aggregates, and as such the result of a kind of synthetic prebiotic biology [1]. In a multiverse perspective, supported by experimental data, I have already proposed the MuGeRo hypothesis in which both cosmic biotic “infection” and abiotic geochemistry contributing to trigger the emergence of life on Earth and beyond [2].
I proposed that spontaneous reactions demonstrated to occur in the environment supposed to exist in the young Earth might have provided the starting organic molecules on which peculiar component of rock (also meteorites) might have act as catalysts of molecular complexity initiating early life processes that, as has been proposed from other Authors are spontaneously and inevitable. In recent decades, the new scientific discipline of synthetic biology has set ambitious goals by pursuing the full design and manufacture of complete genetic circuits, or entire genomes, or even the whole minimal life in the laboratory. I hold that synthetic biology could also throw new and interesting perspectives on the topic of the origins of life and that, moreover, it could help challenge the most commonly accepted definitions of life, thus changing the way we might rethink life and its origins. Infact, following the bottom-up approach I reported experimental evidence that both extraterrestrial and terrestrial minerals and rocks containing iron produces the self-organizing M4 material (Fig.1 a-h) endowed of amino sugar-driven prebiotic synthetic processes supporting abiogenesis [2,3].
This is in addition to the hypothesis that early forms of life were already present in our solar system at the time of Earth formation [4].
Following the bottom-up approach and using the self-organized M4 material [5] obtained from meteorites and terrestrial rocks and minerals as a model for the emergence and early evolution of life on Earth, this work proposes an evolutionary scenario that satisfies the known constraints by proposing that life on Earth emerged, fueled by solar radiation, from non-enzymatic, photochemical and self-sustaining reactions, surviving through some form of redox chemistry.
The M4 material autopoietically self-assembled on hypersthenic chondrite or siderite and on fragments of same terrestrial rocks containing iron could have contributed to the chemical evolution of biomolecules by own catalytic activities that modify sugars and amino acids produced in the prebiotic environments.
Here I’m proposing that these non-enzymatic, self-sustaining, photochemical reactions might be a primitive examples of reaction network supporting abiogenic development of early life on Earth and/or beyond. Indeed, these non-enzymatic reactions appear efficient enough to provide the variety and abundance of biologically favorable molecules from which Darwinian selection operating at molecular level may have seeded protometabolic reaction in the pre-biotic contexts.
The aim of this work here is to present and discuss the new results of my ongoing experiments compared to those obtained in the past and more recently.
Indeed, the results that I obtained so far do not prove or exclude the possibility that M4 materials could be a kind of non-conventional form of pre-terrestrial life or earthly early life but demonstrate that they are certainly the results of reactions depending on mineral or rock (meteorites too) that might be considered prebiotic catalysis probably responsible for the emergence of a large pre-biotic pool of biologically favorable molecules.
Furthermore, I proposed that the photo-geochemical abiotic reactions could have given rise to a variety of independent biogenic events leading to a plurality of Darwinian Initial Life Forms (IDAs) from which the earliest forms of terrestrial life emerged giving rise to more than one LUCA (Last Universal Common Ancestor).
References
1.Longo, A. and Damer, B: Factoring origin of Life Hypotheses into the Search for Life in the Solar System and Beyond., Life, 2020, 10, 5:52,
2.del Gaudio, R.: Understanding the key requirement and the conditions that sparked life on Earth and beyond:clues and new knowledges supporting MuGeRo hypothesis., Europlanet Science Congress 2020, online, https://doi.org/10.5194/epsc2020-167, 2020.
3.del Gaudio, R.,: Transition from Non-Living to Living Matter: filling the gap with a laboratory-based approach according to a Land-based birthplace and Iron catalysis hypotheses at the origin of life on the early Earth and beyond., Europlanet Science Congress-DPS Joint Meeting 2019, Vol. 13, EPSC-DPS2019-80-1 EPSC-DPS2019-80-1.
4. Geraci, G., del Gaudio, R., D'Argenio, B., Rendiconti Lincei, Vol. 12, pp. 51-68, 2001.
5. Geraci, G., D’Argenio, B., del Gaudio R. Patent US9328337 B2, granted, 2016.
How to cite: del Gaudio, R.: Transition from Non-living to living Matter: can integration of MuGeRo hypothesis and synthetic prebiotic biology laboratory approach shed light on the origin of Life?, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-347, https://doi.org/10.5194/epsc2021-347, 2021.
Phosphorous, P, is a key biological element with major roles in replication, information transfer, and metabolism (Maciá, 2005). Interplanetary dust particles contain ∼0.1% P by weight, and meteoric ablation in the 1 μbar region of a planetary upper atmosphere will inject P, PO etc. into the atmosphere. These species will then undergo atmospheric processing before deposition at the surface. Orthophosphate (oxidation state +5) is the dominant form of inorganic P at the Earth’s surface; however, due to the low water solubility and reactivity of P(+5) salts, they have a poor bio-availability (Redfield, 1958). In contrast, less oxidised forms of P (particularly oxidation state +3) are far more bio-available. It has been suggested that these reduced forms of P may have originated from extra-terrestrial material that fell to Earth during the heavy bombardment period.
Previous studies have focused on the direct delivery of P to the surface in meteorites, to undergo processing through aqueous phase chemistry (Pasek, 2008). In contrast, the atmospheric chemistry of P has so far been ignored. Most of the mass of extra-terrestrial P entering a planetary atmosphere is carried by interplanetary dust particles (IPDs) with a mass of ~5 μg and a radius of ~100 μm (Carrillo-Sánchez et al., 2016). A substantial fraction of these particles ablate due to aerobraking, at heights of ~80 km on Mars, 92 km on Earth, and 115 km on Venus (Carrillo-Sánchez et al., 2020). The vaporized P atoms will then undergo chemical processing to form a variety of compounds, in which P may exist in different oxidation states due to the presence of both oxidizing and reducing agents in the upper atmospheres of the terrestrial planets. Here we present the first study of the meteoric ablation of phosphorous, and its subsequent chemical processing to form a variety of compounds including P in the biologically important P(+3) state.
The ablation of PO – relative to Ca – was studied in the Leeds Meteoric Ablation Simulator, and a new version of our Chemical Ablation Model (CABMOD) was developed to include the thermodynamics of P oxides in a molten meteoroid (Carrillo-Sánchez et al., 2020). The speciation of P in anhydrous chondritic porous Interplanetary Dust Particles was made by K-edge X-ray absorption near edge structure (XANES) spectroscopy at the Diamond Synchrotron; this work demonstrated that P mainly occurs in phosphate-like domains. An astronomical dust model which predicts the amounts of dust in the inner solar system produced by Jupiter Family comets, the asteroid belt, and Long Period comets, was then combined with CABMOD to predict the injection rate profile of P, PO and PO2 into the atmospheres of Mars, Earth and Venus - the Meteoric Input Function (Carrillo-Sánchez et al., 2020).
We then measured the kinetics of P, PO and OPO with a variety of atmospheric constituents using the laser flash photolysis/laser induced fluorescence technique (Douglas et al., 2019; Douglas et al., 2020). Electronic structure (ab initio quantum) calculations were also combined with statistical rate theory to produce an atmospheric chemistry network for phosphorus (Figure 1). This network shows the pathways from OPO to H3PO3 and H3PO4. These phosphorus-oxy acids then combine with the metal-containing molecules (e.g. NaHCO3, FeOH), also produced by meteoric ablation, to form metal phosphites and phosphates. These compounds polymerize into nm-sized meteoric smoke particles, which are transported down to the surface over several years (Dhomse et al., 2013).
This chemistry, together with the phosphorus MIF, was then put into the global chemistry-climate model WACCM. Figure 2 shows the predicted percentage of P(+3) to total P in meteoric smoke particles above 60 km, as a function of latitude and season. This study demonstrates that biologically important phosphorous acid (H3PO3) can form and then react with meteoric metal species to generate bio-available metal hydrogen phosphites. The global input of reduced P(+3) to the Earth’s surface is estimated to be around 600 kg year-1.
Figure 1. Schematic diagram of the chemistry of phosphorus in the earth’s mesosphere and lower thermosphere. The green and red arrows indicate the important pathways from OPO to H3PO3 and H3PO4, respectively.
Figure 2. Percentage of P(+3) to total P in meteoric smoke particles above 60 km, as a function of latitude and month (averaged over 3 years).
References
Carrillo-Sánchez, J.D., Bones, D.L., Douglas, K.M., Flynn, G.J., Wirick, S., Fegley, B., Araki, T., Kaulich, B., Plane, J.M.C., 2020. Injection of meteoric phosphorus into planetary atmospheres. Planet. Space Sci. 187, art. no. 104926.
Carrillo-Sánchez, J.D., Nesvorny, D., Pokorny, P., Janches, D., Plane, J.M.C., 2016. Sources of cosmic dust in the Earth's atmosphere. Geophys. Res. Lett. 43, 11979-11986.
Dhomse, S.S., Saunders, R.W., Tian, W., Chipperfield, M.P., Plane, J.M.C., 2013. Plutonium-238 observations as a test of modeled transport and surface deposition of meteoric smoke particles. Geophys. Res. Lett. 40, 4454-4458.
Douglas, K.M., Blitz, M.A., Mangan, T.P., Plane, J.M.C., 2019. Experimental Study of the Removal of Ground- and Excited-State Phosphorus Atoms by Atmospherically Relevant Species. J. Phys. Chem. A 123, 9469-9478.
Douglas, K.M., Blitz, M.A., Mangan, T.P., Western, C.M., Plane, J.M.C., 2020. Kinetic Study of the Reactions PO + O2 and PO2 + O3 and Spectroscopy of the PO Radical. J. Phys. Chem. A 124, 7911-7926.
Maciá, E., 2005. The role of phosphorus in chemical evolution. Chemical Society Reviews 34, 691-701.
Pasek, M.A., 2008. Rethinking early Earth phosphorus geochemistry. Proceedings of the National Academy of Sciences 105, 853-858.
Redfield, A.C., 1958. The biological control of chemical factors in the environment. American Scientist 46, 205-221.
How to cite: Plane, J., Feng, W., and Douglas, K.: Phosphorus Chemistry in Planetary Upper Atmospheres, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-322, https://doi.org/10.5194/epsc2021-322, 2021.