Uno de los personajes más exitosos y conocidos de la historia de la literatura y el cine de ficción es el creado por la escritora Mary Shelley en 1817 en su libro "Frankenstein o el moderno Prometeo". Paradójicamente, uno de los científicos menos conocidos y más misteriosos de la historia de la ciencia británica es Andrew Crosse, el individuo real en el que, según se suele afirmar, Mary Shelley basó su historia(Haining, 1979). Durante los trabajos de documentación científica de la exposición "CRISTALES: UN MUNDO POR DESCUBRIR" hemos topado con varios artículos sobre este experto en electrocristalización que protagonizó uno de los episodios más controvertidos de la historia de la ciencia del siglo XIX, cuando se dieron a conocer sus experimentos sobre creación de vida en el laboratorio. Los enigmáticos experimentos que dieron lugar a la polémica son muy similares desde el punto de vista químico a los experimentos conocidos como jardines químicos. En este trabajo discuto esta propuesta y su relevancia en el contexto histórico de las investigaciones sobre creación de vida. ; European Research Council dentro del European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement nº 340863 ; Peer reviewed
The authors thank the European Research Council under the European Union's Seventh Framework Program (FP7/20072013)/ERC grant agreement no 340863 and ERC PoC LACRYS (837874) as well as Junta de Andalucia for financing the project P18-FR-5008. HC thanks the Deutsche Forschungsgemeinschaft DFG for financial support of the work on Biomorphs (CO 194/28-1). M.M., A.M., and A.M.-P. thank MIUR, (PRIN 2017) 2017E44A9P. Open access funding enabled and organized by Projekt DEAL. ; Photochemical activation is proposed as a general method for controlling the crystallization of sparingly soluble carbonates in space and time. The photogeneration of carbonate in an alkaline environment is achieved upon photo-decarboxylation of an organic precursor by using a conventional 365 nm UV LED. Local irradiation was conducted focusing the LED light on a 300 μm radius spot on a closed glass crystallization cell. The precursor solution was optimized to avoid the precipitation of the photoreaction organic byproducts and prevent photo-induced pH changes to achieve the formation of calcium carbonate only in the corresponding irradiated area. The crystallization was monitored in real-time by time-lapse imaging. The method is also shown to work in gels. Similarly, it was also shown to photo-activate locally the formation of barium carbonate biomorphs. In the last case, the morphology of these biomimetic structures was tuned by changing the irradiation intensity. ; European Research Council under the European Union's Seventh Framework Program (FP7/20072013)/ERC grant 340863 ; ERC PoC LACRYS 837874 ; Junta de Andalucia P18-FR-5008 ; German Research Foundation (DFG) CO 194/28-1 ; Ministry of Education, Universities and Research (MIUR) ; Research Projects of National Relevance (PRIN) 2017E44A9P ; Projekt DEAL
The identification of cellular life in the rock record is problematic, since microbial life forms, and particularly bacteria, lack sufficient morphologic complexity to be effectively distinguished from certain abiogenic features in rocks. Examples include organic pore-fillings, hydrocarbon-containing fluid inclusions, organic coatings on exfoliated crystals and biomimetic mineral aggregates (biomorphs). This has led to the interpretation and re-interpretation of individual microstructures in the rock record. The morphologic description of entire populations of microstructures, however, may provide support for distinguishing between preserved micro-organisms and abiogenic objects. Here, we present a statistical approach based on quantitative morphological description of populations of microstructures. Images of modern microbial populations were compared to images of two relevant types of abiogenic microstructures: interstitial spaces and silica–carbonate biomorphs. For the populations of these three systems, the size, circularity, and solidity of individual particles were calculated. Subsequently, the mean/SD, skewness, and kurtosis of the statistical distributions of these parameters were established. This allowed the qualitative and quantitative comparison of distributions in these three systems. In addition, the fractal dimension and lacunarity of the populations were determined. In total, 11 parameters, independent of absolute size or shape, were used to characterize each population of microstructures. Using discriminant analysis with parameter subsets, it was found that size and shape distributions are typically sufficient to discriminate populations of biologic and abiogenic microstructures. Analysis of ancient, yet unambiguously biologic, samples (1.0 Ga Angmaat Formation, Baffin Island, Canada) suggests that taphonomic effects can alter morphometric characteristics and complicate image analysis; therefore, a wider range of microfossil assemblages should be studied in the future before automated analyses can be developed. In general, however, it is clear from our results that there is great potential for morphometric descriptions of populations in the context of life recognition in rocks, either on Earth or on extraterrestrial bodies. ; This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Program (grant agreement no. 646894 to MVZ) and under the ERC Seventh Framework Programme FP7/2007- 2013 (grant agreement no. 340863 to JMG-R). JMG-R also acknowledges the Ministerio de Economía y Competitividad of Spain through the project CGL2016-78971-P. We are grateful to seven anonymous reviewers for their helpful comments. We thank four anonymous reviewers for their useful comments which greatly improved a previous version of the manuscript. This is IPGP contribution n°4098.
The goal of prebiotic chemistry is the depiction of molecular evolution events preceding the emergence of life on Earth or elsewhere in the cosmos. Plausible experimental models require geochemical scenarios and robust chemistry. Today we know that the chemical and physical conditions for life to flourish on Earth were at work much earlier than thought, i.e., earlier than 4.4 billion years ago. In recent years, a geochemical model for the first five hundred million years of the history of our planet has been devised that would work as a cradle for life. Serpentinization processes in the Hadean eon affording self-assembled structures and vesicles provides the link between the catalytic properties of the inorganic environment and the impressive chemical potential of formamide to produce complete panels of organic molecules relevant in pre-genetic and pre-metabolic processes. Based on an interdisciplinary approach, we propose basic transformations connecting geochemistry to the chemistry of formamide, and we hint at the possible extension of this perspective to other worlds. ; Agenzia Spaziale Italiana (ASI) ASI DC-VUM-2017-034 2019-3-U.0 CUP F86C16000000006 ; European Research Council (ERC) 340863 ; Spanish Government CGL2016-78971-P ; Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades of Junta de Andalucia PY18-5008
The authors thank the European Research Council under the European Union's seventh Framework Program (FP7/2007-2013)/ERC grant agreement no. 340863 and the Spanish "Ministerio de Educacion y Ciencia" for the financial support of the project CGL2016-78971-P, the Italian Space Agency for co-funding the Life in Space project (ASI N. 2019-3-U.0) and MIUR 2017-PNR cod. 2017BMK8JR. This work is supported by the Italian Space Agency (ASI) DC-VUM-2017-034 contratto ASI N. 2019-3-U.0, CUP F86C16000000006 "Vita nello spazioOrigine, presenza, persistenza della vita nello spazio, dalle molecole agli estremofili". ; We have designed a set of experiments to test the role of borosilicate reactor on the yielding of the Miller–Urey type of experiment. Two experiments were performed in borosilicate flasks, two in a Teflon flask and the third couple in a Teflon flask with pieces of borosilicate submerged in the water. The experiments were performed in CH4, N2, and NH3 atmosphere either buffered at pH 8.7 with NH4Cl or unbuffered solutions at pH ca. 11, at room temperature. The Gas Chromatography-Mass Spectroscopy results show important differences in the yields, the number of products, and molecular weight. In particular, a dipeptide, multi-carbon dicarboxylic acids, PAHs, and a complete panel of biological nucleobases form more efficiently or exclusively in the borosilicate vessel. Our results offer a better explanation of the famous Miller's experiment showing the efficiency of borosilicate in a triphasic system including water and the reduced Miller–Urey atmosphere. ; European Research Council (ERC) 340863 ; Spanish Government CGL2016-78971-P ; Agenzia Spaziale Italiana (ASI) 2019-3-U.0 ; Ministry of Education, Universities and Research (MIUR) 2017BMK8JR ; Agenzia Spaziale Italiana (ASI) 2019-3-U.0 DC-VUM-2017-034 CUP F86C16000000006
The precipitation of barium and strontium carbonate in alkaline silica gels or silica solutions produces nanocrystalline self-assembled composite materials displaying biomimetic shapes and textures. We have crystallized concomitantly in time and space two anhydrous polymorphs of calcium carbonate, under similar conditions at different temperatures. The orthorhombic phase aragonite produces nanocrystalline aggregates exhibiting non-crystallographic morphologies and complex textures characteristic of silica biomorphs. Conversely, the simultaneously forming trigonal phase, calcite, yields rhombohedral crystals that experience fibrous growth and that maintain memory of the point symmetry group of the crystalline structure. Experiments performed at different temperatures (room temperature, 45, 60 and 80 °C) revealed that the higher the temperature the higher the aragonite/calcite precipitation ratio, but the crystallization of calcite was never fully inhibited. We have studied the growth mechanism, the growth texture and the morphogenesis for both cases. We have found that the dramatic difference between the crystallization behaviours of the two mineral phases is due to the difference in the growth mechanism at the nanoscale. ; The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 340863. G. Zhang acknowledges the Spanish Consejo Superior de Investigaciones Científicas for the pre-doctoral fellowship, within the programme ''Junta para la Ampliación de Estudios''. The authors also acknowledge Alicia González Segura from the Centre of Scientific Instrumentation of the University of Granada for her technical assistance.
We want to thank again our commentators for their stimulating ideas and insightful comments that we are sure helped to clarify and develop our ideas. Authors acknowledge funding from the European Research Council (ERC) under the European Union's Seven Framework Program grant agreement n∘ 340863 (JMG-R) and under the Horizon 2020 research and innovation program grant agreement n∘ 646894 (MvZ). JMG-R also acknowledges the Ministerio de Economía y Competitividad of Spain for funding the project CGL2016-78971-P . This is IPGP contribution n∘ 4161 .
The condensation of formamide has been shown to be a robust chemical pathway affording molecules necessary for the origin of life. It has been experimentally demonstrated that condensation reactions of formamide are catalyzed by a number of minerals, including silicates, phosphates, sulfides, zirconia, and borates, and by cosmic dusts and meteorites. However, a critical discussion of the catalytic power of the tested minerals, and the geochemical conditions under which the condensation would occur, is still missing. We show here that mineral self‐assembled structures forming under alkaline silica‐rich solutions are excellent catalysts for the condensation of formamide with respect to other minerals. We also propose that these structures were likely forming as early as 4.4 billion years ago when the whole earth surface was a reactor, a global scale factory, releasing large amounts of organic compounds. Our experimental results suggest that the conditions required for the synthesis of the molecular bricks from which life self‐assembles, rather than being local and bizarre, appears to be universal and geologically rather conventional. ; We acknowledge funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007–2013)/European Research Council grant agreement no. 340863 (Prometheus). Spanish Ministerio de Economia y Competitividad is acknowledged for Project CGL2016‐78971‐P, AEI/FEDER. MIUR Ministero dell′Istruzione, dell′Università della Ricerca and Scuola Normale Superiore (Pisa, Italy), project PRIN 2015 STARS in the CAOS—Simulation Tools for Astrochemical Reactivity and Spectroscopy in the Cyberinfrastructure for Astrochemical Organic Species, cod. 2015F59J3R, is acknowledged. This work was supported by COST Action TD 1308.
The condensation of formamide has been shown to be a robust chemical pathway affording molecules necessary for the origin of life. It has been experimentally demonstrated that condensation reactions of formamide are catalyzed by a number of minerals, including silicates, phosphates, sulfides, zirconia, and borates, and by cosmic dusts and meteorites. However, a critical discussion of the catalytic power of the tested minerals, and the geochemical conditions under which the condensation would occur, is still missing. We show here that mineral self-assembled structures forming under alkaline silica-rich solutions are excellent catalysts for the condensation of formamide with respect to other minerals. We also propose that these structures were likely forming as early as 4.4 billion years ago when the whole earth surface was a reactor, a global scale factory, releasing large amounts of organic compounds. Our experimental results suggest that the conditions required for the synthesis of the molecular bricks from which life self-assembles, rather than being local and bizarre, appears to be universal and geologically rather conventional. ; We acknowledge funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007–2013)/European Research Council grant agreement no. 340863(Prometheus). Spanish Ministerio de Economia y Competitividad is acknowledged for Project CGL2016-78971-P , AEI/FEDER. MIUR Ministero dell'Istruzione, dell'Universit/ della Ricerca and Scuola Normale Superiore (Pisa, Italy), project PRIN 2015 STARS in the CAOS—SimulationTools for Astrochemical Reactivityand Spectroscopy in the Cyberinfrastructure for Astrochemical OrganicSpecies, cod. 2015F59J3R,isacknowledged.This work was supported by COST Action TD 1308
Beyond fundamental aspects of crystal growth and morphology, the growth of minerals is a challenging subject because in most cases we face a problem with unknown growth conditions. Actually, in the field of geological studies, we have to decipher the growth conditions of a crystal using the information contained in the very crystal. One of these characteristics of crystals that contain information about their growth is their morphology and time evolution. In this article, we introduce the subject of crystal morphology by using three important minerals, calcite, halite and gypsum, as three didactic case studies to illustrate the application of the current knowledge in the field. ; D.A. and L.P. are grateful to Marco Rubbo and Marco Bruno (DST-Torino) for their fruitful discussion and cooperation. J.M.G-R. and F.O. acknowledge funding from the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement n° 340863, and from the Ministerio de Economía y Competitividad, proyecto CGL2013-43371-P
The so-called "biomorphs" are a fascinating and beautiful group of polycrystalline, self-assembled silicaalkaline carbonate composite materials, which are usually obtained by crystallization process of carbonates with the presence of silica in alkaline environments. They are characterized by the hierarchy of their structures in addition to complex and curved morphologies which resemble the morphologies of crystallization under the control of living organisms. The first work related to biomorphs was reported in the 1980s, in which barium carbonate was slowly crystallized in alkaline silica gel by counterdiffusion method and biomorphic barium carbonate with noncrystallographic twisted ribbon was formed (Garcia-Ruiz, 1985) ; European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) ERC grant agreement nº 340863 / JAE-PRE program ; Peer reviewed
[EN] The search for signs of life in the ancient rock record, extreme terrestrial environments, and other planetary bodiesrequires a well-established, universal, and unambiguous test of biogenicity. This is notably true for cellular remnantsof microbial life, since their relatively simple morphologies resemble various abiogenic microstructures that occur innature. Although lists of qualitative biogenicity criteria have been devised, debates regarding the biogenicity of manyancient microfossils persist to this day. We propose here an alternative quantitative approach for assessing thebiogenicity of putative microfossils. In this theoretical approach, different hypotheses—involving biology or not anddepending on the geologic setting—are put forward to explain the observed objects. These hypotheses correspond tospecific types of microstructures/systems. Using test samples, the morphology and/or chemistry of these systems arethen characterized at the scale of populations. Morphologic parameters include, for example, circularity, aspect ratio,and solidity, while chemical parameters could include elementary ratios (e.g., N/C ratio), isotopic enrichments (e.g.,d13C), or chirality (e.g., molar proportion of stereoisomers), among others. Statistic trends distinguishing the differentsystems are then searched for empirically. The trends found are translated into ''decision spaces'' where the differentsystems are quantitatively discriminated and where the potential microfossil population can be located as a singlepoint. This approach, which is formulated here on a theoretical level, will solve several problems associated with theclassical qualitative criteria of biogenicity. Most importantly, it could be applied to reveal the existence of cellular lifeon other planets, for which characteristics of morphology and chemical composition are difficult to predict. ; The Ministerio de Economia y competividad of Spain for funding the project CLG2016-78971-P. This project has received funding from the EuropeanResearch Council, under the European Union's Horizon2020 research and innovation programme (grant agreementno. 694894) and the Seventh Framework Programme-FP7/2007-2013 (grant agreement no. 340863) ; Peer reviewed
Archean hydrothermal environments formed a likely site for the origin and early evolution of life. These are also the settings, however, were complex abiologic structures can form. Low-temperature serpentinization of ultramafic crust can generate alkaline, silica-saturated fluids in which carbonate–silica crystalline aggregates with life-like morphologies can self-assemble. These "biomorphs" could have adsorbed hydrocarbons from Fischer–Tropsch type synthesis processes, leading to metamorphosed structures that resemble carbonaceous microfossils. Although this abiogenic process has been extensively cited in the literature and has generated important controversy, so far only one specific biomorph type with a filamentous shape has been discussed for the interpretation of Archean microfossils. It is therefore critical to precisely determine the full distribution in morphology and size of these biomorphs, and to study the range of plausible geochemical conditions under which these microstructures can form. Here, a set of witherite-silica biomorph synthesis experiments in silica-saturated solutions is presented, for a range of pH values (from 9 to 11.5) and barium ion concentrations (from 0.6 to 40 mmol/L BaCl2). Under these varying conditions, a wide range of life-like structures is found, from fractal dendrites to complex shapes with continuous curvature. The size, spatial concentration, and morphology of the biomorphs are strongly controlled by environmental parameters, among which pH is the most important. This potentially limits the diversity of environments in which the growth of biomorphs could have occurred on Early Earth. Given the variety of the observed biomorph morphologies, our results show that the morphology of an individual microstructure is a poor criterion for biogenicity. However, biomorphs may be distinguished from actual populations of cellular microfossils by their wide, unimodal size distribution. Biomorphs grown by diffusion in silica gel can be differentiated by their continuous gradient in size, spatial density, and morphology along the direction of diffusion. ; This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement nº 646894) and under the ERC Seventh Framework Programme FP7/2007-2013 (grant agreement n° 340863). JMG-R also acknowledges the Ministerio de Economía y Competitividad of Spain through the project CGL2016-78971-P. We acknowledge the analytical platform PARI and Stefan Borenstazjn for SEM imaging. Prof. Y. Tsukii and The Protist Information Server (http://protist.i.hosei.ac.jp/) are acknowledged for the use of pictures of cyanobacteria. This is IPGP contribution n° 3912. We are grateful to two anonymous reviewers for their helpful comments.
Archean hydrothermal environments formed a likely site for the origin and early evolution of life. These are also the settings, however, were complex abiologic structures can form. Low-temperature serpentinization of ultramafic crust can generate alkaline, silica-saturated fluids in which carbonate–silica crystalline aggregates with life-like morphologies can self-assemble. These "biomorphs" could have adsorbed hydrocarbons from Fischer–Tropsch type synthesis processes, leading to metamorphosed structures that resemble carbonaceous microfossils. Although this abiogenic process has been extensively cited in the literature and has generated important controversy, so far only one specific biomorph type with a filamentous shape has been discussed for the interpretation of Archean microfossils. It is therefore critical to precisely determine the full distribution in morphology and size of these biomorphs, and to study the range of plausible geochemical conditions under which these microstructures can form. Here, a set of witherite-silica biomorph synthesis experiments in silica-saturated solutions is presented, for a range of pH values (from 9 to 11.5) and barium ion concentrations (from 0.6 to 40 mmol/L BaCl). Under these varying conditions, a wide range of life-like structures is found, from fractal dendrites to complex shapes with continuous curvature. The size, spatial concentration, and morphology of the biomorphs are strongly controlled by environmental parameters, among which pH is the most important. This potentially limits the diversity of environments in which the growth of biomorphs could have occurred on Early Earth. Given the variety of the observed biomorph morphologies, our results show that the morphology of an individual microstructure is a poor criterion for biogenicity. However, biomorphs may be distinguished from actual populations of cellular microfossils by their wide, unimodal size distribution. Biomorphs grown by diffusion in silica gel can be differentiated by their continuous gradient in size, spatial density, and morphology along the direction of diffusion. ; This project has received funding from the European Research Council(ERC) under the European Union's Horizon 2020 research and inno -vation programme (grant agreement nº 646894) and under the ERC Seventh Framework Programme FP7/2007-2013 (grant agreementn° 340863). JMG-R also acknowledges the Ministerio de Economía y Competitividad of Spain through the project CGL2016-78971-P. We acknowledge the analytical platform PARI and Stefan Borenstazjnfor SEM imaging. Prof. Y. Tsukii and The Protist Information Server (http://protist.i.hosei.ac.jp/) are acknowledged for the use of picturesof cyanobacteria. This is IPGP contribution n° 3912. We are gratefulto two anonymous reviewers for their helpful comments
Mineral vesicles and chemical gardens are self-organized biomimetic structures that form via abiotic mineral precipitation. These membranous structures are known to catalyze prebiotic reactions but the extreme conditions required for their synthesis has cast doubts on their formation in nature. Apart from model solutions, these structures have been shown to form in serpentinization-driven natural silica-rich water and by fluid-rock interaction of model alkaline solutions with granites. Here, for the first time, we demonstrate that self-assembled hollow mineral vesicles and gardens can be synthesized in natural carbonate-rich soda lake water. We have synthesized these structures by a) pouring saturated metal salt solutions, and b) by immersing metal salt pellets in brines collected from Lake Magadi (Kenya). The resulting structures are analyzed by using SEM coupled with EDX analysis, Raman spectroscopy, and powder X-ray diffraction. Our results suggest that mineral self-assembly could have been a common phenomenon in soda oceans of early Earth and Earth-like planets and moons. The composition of the obtained vesicles and gardens confirms the recent observation that carbonate minerals in soda lakes sequestrate Ca, thus leaving phosphate behind in solution available for biochemical reactions. Our results strengthens the proposal that alkaline brines could be ideal sites for "one-pot" synthesis of prebiotic organic compounds and the origin of life. ; European Research Council (ERC) 340863 ; Spanish Government CGL2016-78971-P ; "Ministerio de Ciencia, Innovacion y Universidades" of the Spanish government BES-2017-081105
