Europlanet Science Congress 2021
Virtual meeting
13 – 24 September 2021
Europlanet Science Congress 2021
Virtual meeting
13 September – 24 September 2021

TP21

TP
The emergence of Life in our Solar System and Beyond 

This session seeks papers on the biological, physicochemical, astrophysical, and paleontological studies of the living-matter origination problem, mechanism, conditions necessary and sufficient for living-matter origination and development on the Earth and other celestial objects; promising celestial objects for the living-matter occurrence, and other experimental, theoretical, and observational works related to the emergence and development of Life in our Solar System and beyond are welcomed.
This includes work related to theme of the Origins of Life to study interstellar chemistry, meteorites and comets chemistry as well as the chemistry of planets. A central issue in the research on the emergence of life is the paradoxical role of water in pre-biotic chemistry. Infact,on the one hand, water is essential for all known life, on the other hand it is highly destructive for key biomolecules such as nucleic and polypeptides.
A truly interdisciplinary approach is needed to delve into the core of the issue of emergence of life, because in addition to physics and chemistry it is also need to deploy a number of other sciences. We rely on contribution caming from mathematical or philosophical perspectives not only on astrobiology moreover we think that a part of the answers may lie in scientists who working on cancer research, genetics, space exploration paleontology who are not necessarily involved in this field. I argue that synthetic biology field, challenging most accepted definitions of life too, might also shed some novel and interesting perspectives on one of the most puzzling unanswered questions of science.

Public information:

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.

Co-organized by EXO
Convener: Rosanna del Gaudio | Co-conveners: Frank Trixler, Terence Kee
Public information:

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

Chairpersons: Terence Kee, Frank Trixler, Rosanna del Gaudio
General Concepts
EPSC2021-14
|
solicited
Sohan Jheeta

It is believed that some of the necessary organic molecules may have been formed in specific areas of space (namely dark molecular clouds, eg Horsehead nebula) and delivered on to the Earth during the early heavy bombardment period of its history, approximately 4.3-4.0 billion years ago. These organic molecules may have played a pivotal role in the formation of life on Earth. In addition, it is believed that life on Earth was formed within a very short geological time frame of only 200-300 million years. So, it is not unreasonable to suppose that these molecules were initially made in space which in effect could be, metaphorically speaking, a huge chemical laboratory.


The research (drawn from my own experimental astrochemistry) highlighted during this oral presentation focuses on the formation of molecules under a variety of simulated space conditions (eg different temperatures, levels of radiation energies and types of impinging radiations). There are two sorts of chemistry that take place in space, solid and gas phase, and although only 25% of the chemistry in space occurs in the solid phase, this will be the focus of my oral presentation.

How to cite: Jheeta, S.: Where were the molecules of life made?, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-14, https://doi.org/10.5194/epsc2021-14, 2021.

EPSC2021-347
Rosanna del Gaudio

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,

https://doi.org/10.3390/life10050052

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.

EPSC2021-373
Andrea Greiner de Herrera and Frank Trixler

The "water paradox" is an obstinate problem in the research on the chemical evolution towards the emergence of life. It states that although aqueous environments are essential for life, they hamper key condensation reactions such as nucleotide polymerisation. To overcome this paradox several hypotheses have been proposed, including scenarios based on alternative solvents like formamide, condensing agents like cyanamide, high temperatures of over 150 °C or wet/dry cycles in surface ponds. However, when appraising the prebiotic plausibility of such scenarios some general weaknesses appear. Besides the fact that all known life manages the water paradox without needing such proposed conditions, the principle that evolution builds on existing pathways indicates that the same physicochemical effects were probably involved in the abiotic origin of biopolymers as now being tapped by life via complex enzymes.

Here we show that abiotic temporal nanoconfinements of water can act as natural reactions vessels for prebiotic RNA formation. We present evidence for spontaneous, abiotic polymerisation of nucleotides in water. According to our results the reaction is enabled by the rise of anomalous properties of water when being temporarily confined between nanoscale separated particles of geological ubiquity within aqueous suspensions. These findings can solve the water paradox in such a way that nanofluidic effects in aqueous particle suspensions open up an abiotic route to biopolymerisation and polymer stabilisation under chemical and thermodynamic conditions which also exist within the intracellular environment of living cells. The fact that polymerase enzymes also form temporal nanoconfined water clusters inside their active site implies that the same physico-chemical effects are tapped for nucleotide condensation in water both by biochemical pathways and the reported abiotic route. This indicates that our model is consistent with evolutionary conservatism stretching back to the era of prebiotic chemical evolution. The consistency is further supported by the fact that water is not trapped by nanoconfinements within the polymerase core but can exchange with the surrounding intracellular fluid – a situation which is also prevalent in nanofluidic environments within aqueous particle suspensions. Our experimental finding that under the reported conditions an amino acid catalyses the abiotic polymerisation of nucleotides may give a hint to a nanofluidic origin of cooperation between amino acids and nucleotides evolving to the interdependent synthesis of proteins and nucleic acids in living cells.

The effect of abiotic RNA polymerisation in temporal nanoconfined water does not depend on highly specific mineral species and geological environments as watery suspensions of micro- and nanoparticles are virtually ubiquitous – they exist, for example, in the form of sediments with pore water, hydrothermal vent fluids containing precipitated inorganic and polyaromatic particles or dispersed aggregates inside water-filled cracks in the crust of the earth and possibly of icy moons in the outer solar system.

References

Greiner de Herrera, A., Markert, T. & Trixler, F. Temporal nanofluidic confinements induce prebiotic condensation in water. Preprint, DOI: 10.21203/rs.3.rs-163645/v3

How to cite: Greiner de Herrera, A. and Trixler, F.: Abiotic RNA Formation in Natural Nanoconfinements of Water: Overcoming the Water Paradox via a Nanofluidic Bridge Between Geochemistry and Biochemistry, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-373, https://doi.org/10.5194/epsc2021-373, 2021.

Environmental Conditions
EPSC2021-322
John Plane, Wuhu Feng, and Kevin Douglas

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.