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The prebiotic origins of biopolymers and metabolic co‐factors are key questions in Origins of Life studies. In a simple warm‐little‐pond model, using a drying phase to produce a urea‐enriched solution, we present a prebiotic synthetic path for the simultaneous formation of neopterins and tetrahydroneopterins, along with purine nucleosides. We show that, in the presence of ribose and in a formylating environment consisting of urea, ammonium formate, and water (UAFW), the formation of neopterins from pyrimidine precursors is robust, while the simultaneous formation of guanosine requires a significantly higher ribose concentration. Furthermore, these reactions provide a tetrahydropterin–pterin redox pair. This model suggests a prebiotic link in the origin of purine nucleosides and pterin cofactors that provides a possible deep prebiotic temporal connection for the emergence of nucleic acids and metabolic cofactors. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue are the groups of César Menor‐Salván, Facundo Fernández and Nicholas V. Hud at the University of Alcala and the Georgia Institute of Technology. The image depicts the authors contemplating the origin of pterins and guanosine nucleosides from a common precursor, with the art‐gallery setting embodying their feeling that the common synthetic pathways of these molecules in both the prebiotic world and in biochemistry is a natural work of (chemical) art. Read the full text of the article at 10.1002/chem.202200714. [ABSTRACT FROM AUTHOR]

One of the major components of the organic solvent extractable fraction of Cretaceous ambers is 1,6-dimethyl-5-isopentyltetralin, a compound that has been incorrectly or not identified in previous reports on the molecular composition of Cretaceous ambers. Here, the purification and structural identification of 1,6-dimethyl-5-isopentyltetralin is reported from amber samples of the Cretaceous Peñacerrada II deposit at Peñacerrada, Álava (Basque-Cantabrian Basin, Spain). The structural identification of 1,6-dimethyl-5-isopentyltetralin allowed the complete identification of related compounds, comprising the family of 1,6-dimethyl-5-alkyltetralins. This suggests that those compounds, with concentrations up to 27% of the total organic extract of amber from Peñacerrada, are characteristic for labdane-type biomarkers in Cretaceous fossil resins and their distributions indicate different compositional families, related to their botanical and topographic origin. Also, the name amberene is proposed for the main molecule of this group. The relative proportion of the amberene-type compounds suggests three compositional families for the Cretaceous Spanish ambers. [ABSTRACT FROM AUTHOR]

Keywords: pterins; guanosine; origins of life; RNA world; phosphorylation EN pterins guanosine origins of life RNA world phosphorylation 1 1 1 07/13/22 20220711 NES 220711 B Guanosine and pterins are depicted as the constellation Gemini b . However, like Pollux from Greek mythology, guanosine would not have been born alone - pterins would have been formed in equal (or, in this case, even in major) parts through prebiotic reactions. Pterins, guanosine, origins of life, RNA world, phosphorylation. [Extracted from the article]

The origin of nucleobases and other heterocycles is a classic question in the chemistry of the origins of life. The construction of laboratory models for the abiotic synthesis of nitrogen heterocycles in plausible natural conditions also aids the understanding and prediction of chemical species in the Solar System. Here, we report a new explanation for the origin of hydantoins, purines, and pyrimidines in eutectic water/ice/urea solutions driven by ultraviolet irradiation (in the 185-254 nm range, UVC) of acetylene under anoxic conditions. An analysis of the products indicates the synthesis of hydantoin and 5-hydroxyhydantoin, the purines uric acid, xanthine, and guanine, and the pyrimidines uracil and cytosine. The synthesis occurred together with the photo-oxidation of bases in a complex process for which possible pathways are proposed. In conclusion, an acetylene-containing atmosphere could contribute to the origin of nucleobases in the presence of a urea/water system by an HCN-independent mechanism. The presence of ice has a dual role as a favorable medium for the synthesis of nucleobases and protection against degradation and as a source of free radicals for the synthesis of highly oxidized heterocycles. A mechanism for the origin of hydantoins and uracil from urea in plausible conditions for prebiotic chemistry is also proposed. [ABSTRACT FROM AUTHOR]

Abstract: The composition of terpenoids from well preserved Cretaceous fossil resins and plant tissues from the amber bearing deposits of El Soplao and Reocín in Cantabria (northern Spain) have been analyzed using gas chromatography–mass spectrometry and the results are discussed using the terpenoid composition of extant conifers as a reference. Amber is present at many horizons within two units of coastal to shallow marine siliciclastics of Albian and Cenomanian age. The fossil resins are associated with black amber (jet) and abundant, well preserved plant cuticle compressions, especially those of the extinct conifer genus Frenelopsis (Cheirolepidiaceae). We report the molecular characterization of two types of amber with different botanical origins. One of them is characterized by the significant presence of phenolic terpenoids (ferruginol, totarol and hinokiol) and pimaric/isopimaric acids, as well as their diagenetic products. The presence of phenolic diterpenoids together with the lack of abietic and dehydroabietic acids excludes both Pinaceae and Araucariaceae as sources for this type of amber. The biological diterpenoid composition is similar to that observed for extant Cupressaceae. The second type of amber is characterized by the absence of phenolic terpenoids and other specific biomarkers. Some terpenoids with uncertain structure were detected, as well as the azulene derivative guaiazulene. Our results suggest that the amber from Cantabria could be fossilized resin from Frenelopsis and other undetermined botanical sources. The biological terpenoid assemblage confirms a chemosystematic relationship between Frenelopsis and modern Cupressaceae. [Copyright &y& Elsevier]

Abstract: Two different simulation experiments of prebiotic synthesis were carried out in a CH4/N2/H2 atmosphere with spark discharge activation of aqueous aerosols and liquid water. In both cases, a hydrophilic tholin and a hydrophobic tholin were obtained. The methodology developed by our group for the characterisation of hydrophilic tholins [Ruiz-Bermejo, M., Menor-Salván, C., Mateo-Martí, E., Osuna-Esteban, S., Martín-Gago, J.A., Veintemillas-Verdaguer, S., 2008. Icarus 198, 232–241] was used in order to study the hydrophobic tholins. The gas precursors of the tholins from mixtures containing CH4, with and without H2, were studied. We propose that the formation of the hydrophobic tholins involves the formation of unsaturated oligomeric hydrocarbon chains from vinyl and acetylene monomers, as well as allene derivatives formed in the gas phase after the incorporation of polar groups into these hydrocarbon chains. Finally, we compare our results concerning hydrophobic tholins with HCN polymers, since it is generally suggested that the polymeric material formed in spark experiments are possible oligomers of HCN, and that Titan’s tholins could be poly-HCN. [Copyright &y& Elsevier]

Abstract: Tholins are complex organic materials produced by irradiation of several carbon and nitrogen rich atmospheres. They could have played a key role in the origin of life on Earth because their ability to release important bioorganics, which are nowadays present in proteins, nucleic-acid bases and other important biostructures. Usually, the yield of these compounds is higher after acid hydrolysis, however little is known about the structure and chemical composition of the tholins. In this work, we propose the use of different spectroscopic and separation techniques, which are not usually applied in this field, in order to obtain complete information about the tholin structure and behavior. Two different simulation experiments of prebiotic synthesis were carried out in CH4/N2/H2 atmosphere out from spark discharge activation of aqueous aerosols and liquid water, respectively. In both cases, a hydrophilic tholin and a hydrophobic tholin were obtained. Herein, we report the application of this methodology to our hydrophilic tholins and we review, briefly, some astrobiological aspects related to these complex substances. [Copyright &y& Elsevier]

The idea of an autotrophic organism as the first living being on Earth leads to the hypothesis of a protometabolic, complex chemical system. In one of the main hypotheses, the first metabolic systems emerged from the interaction between sulfide minerals and/or soluble iron-sulfide complexes and fluids rich in inorganic precursors, which are reduced and derived from crustal or mantle activity. Within this context, the possible catalytic role of pyrrhotite, one of the most abundant sulfide minerals, in biomimetic redox and carbon fixation reactions was studied. Our results showed that pyrrhotite, under simulated hydrothermal conditions, could catalyze the pyruvate synthesis from lactate and that a dynamic system formed by coupling iron metal and iron-sulfur species in an electrochemical cell could promote carbon fixation from thioacetate esters. [ABSTRACT FROM AUTHOR]

Dinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here, we describe the amber from the Lower Cretaceous dinosaur bonebed of Ariño (Teruel, Spain) using a multidisciplinary approach. Amber is found in both a root layer with amber strictly in situ and a litter layer mainly composed of aerial pieces unusually rich in bioinclusions, encompassing 11 insect orders, arachnids, and a few plant and vertebrate remains, including a feather. Additional palaeontological data--charophytes, palynomorphs, ostracods--are provided. Ariño arguably represents the most prolific and palaeobiologically diverse locality in which fossiliferous amber and a dinosaur bonebed have been found in association, and the only one known where the vast majority of the palaeontological assemblage suffered no or low-grade pre-burial transport. This has unlocked unprecedentedly complete and reliable palaeoecological data out of two complementary windows of preservation--the bonebed and the amber--from the same site. [ABSTRACT FROM AUTHOR]

This study presents the thermogravimetry (TG) of hydrophobic tholins, obtained from different simulation experiments of prebiotic synthesis carried out in a CH/N/H atmosphere with spark discharge activation of aqueous aerosols and liquid water. Differential thermal analysis and differential scanning calorimetry were also used to evaluate the thermal behaviour of these complex organic compounds that could play an important role in prebiotic chemistry. A coupled thermogravimetry-mass spectrometry system allowed us to analyse the principal volatile thermal decomposition and fragmentation products of the hydrophobic tholins under dynamic conditions and an inert atmosphere. During their thermal degradation, which occurs in two stages, a wide variety of hydrocarbon products including methane, vinyl monomers (such as ethylene and propylene), acetylene, oligomers, and some other unknown compounds are found. Besides, a thermally stable structure is present (graphitic structure) in these particular organic substances. Finally, data collected from TG experiments in an oxidative atmosphere showed significant differences at temperatures above 240 °C. According to these results, the different techniques of thermal analysis here applied have proved to be an adequate methodology for the study and characterization of these complex systems, structures of which remain controversial even in these days. [ABSTRACT FROM AUTHOR]

Abstract: The primary geochemical process at methane seeps is anaerobic oxidation of methane (AOM), performed by methanotrophic archaea and sulfate-reducing bacteria (SRB). The molecular fingerprints (biomarkers) of these chemosynthetic microorganisms can be preserved in carbonates formed through AOM. However, thermal maturity and aerobic degradation can change the original preserved compounds, making it difficult to establish the relation between AOM and carbonate precipitation. Here we report a study of amino acid and lipid abundances in carbonate matrices of aerobically altered pipes recovered from the seafloor of the Gulf of Cadiz (SW Iberian Peninsula). This area is characterized by a complex tectonic regime that supports numerous cold seeps. Studies so far have not determined whether the precipitation of carbonate pipes in the Gulf of Cadiz is a purely chemical process or whether microbial communities are involved. Samples from this site show signs of exposure to oxygenated waters and of aerobic alteration, such as oxidation of authigenic iron sulfides. In addition, the degradation index, calculated from the relative abundance of preserved amino acids, indicates aerobic degradation of organic matter. Although crocetane was the only lipid identified from methanotrophic archaea, the organic compounds detected (n-alkanes, regular isoprenoids and alcohols) are compatible with an origin from AOM coupled with bacterial sulfate reduction (BSR) and subsequent aerobic degradation. We establish a relation among AOM, BSR and pipe formation in the Gulf of Cadiz through three types of analysis: (1) stable carbon and oxygen isotopic composition of carbonate minerals; (2) carbonate microfabrics; and (3) mineralogical composition. Our results suggest that carbonate pipes may form through a process similar to the precipitation of vast amounts of carbonate pavements often found at cold seeps. Our approach suggests that some organic compound patterns, in combination with additional evidence of AOM and BSR, may help indicate the source of altered methane-derived carbonates commonly occurring in ancient and modern deposits. [Copyright &y& Elsevier]

Abstract: This paper presents a thermogravimetry (TG) study of hydrogen cyanide polymers, synthesized from the reaction of equimolar aqueous solutions of sodium cyanide and ammonium chloride. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were also used to evaluate the thermal behaviour of these black polymers, which play an important role in prebiotic chemistry. A coupled TG–mass spectrometer (MS) system allowed us to analyze the principal volatile thermal decomposition and fragmentation products of the isolated HCN polymers under dynamic conditions and an inert atmosphere. After dehydration, a multi-step decomposition occurred in this particular polymeric system, due to the release of ammonia, hydrogen cyanide (depolymerization reaction), isocyanic acid (or cyanic acid) and formamide; these two latter species allow us identify bond connectivities. Finally, data collected from TG experiments in an oxidative atmosphere showed significant differences at higher temperatures, above 400 °C. According to these results, the different techniques of thermal analysis here applied have demonstrated to be an adequate methodology for the study and characterization of this complex macromolecular system, whose structure remains controversial even today. [Copyright &y& Elsevier]

Organophosphates were likely an important class of prebiotic molecules. However, their presence on the early Earth is strongly debated because the low availability of phosphate, which is generally assumed to have been sequestered in insoluble calcium and iron minerals, is widely viewed as a major barrier to organophosphate generation. Herein, we demonstrate that cyanide (an essential prebiotic precursor) and urea‐based solvents could promote nucleoside phosphorylation by transforming insoluble phosphate minerals in a "warm little pond" scenario into more soluble and reactive species. Our results suggest that cyanide and its derivatives (metal cyanide complexes, urea, ammonium formate, and formamide) were key reagents for the participation of phosphorus in chemical evolution. These results allow us to propose a holistic scenario in which an evaporitic environment could concentrate abiotically formed organics and transform the underlying minerals, allowing significant organic phosphorylation under plausible prebiotic conditions. [ABSTRACT FROM AUTHOR]

Organophosphates were likely an important class of prebiotic molecules. However, their presence on the early Earth is strongly debated because the low availability of phosphate, which is generally assumed to have been sequestered in insoluble calcium and iron minerals, is widely viewed as a major barrier to organophosphate generation. Herein, we demonstrate that cyanide (an essential prebiotic precursor) and urea‐based solvents could promote nucleoside phosphorylation by transforming insoluble phosphate minerals in a "warm little pond" scenario into more soluble and reactive species. Our results suggest that cyanide and its derivatives (metal cyanide complexes, urea, ammonium formate, and formamide) were key reagents for the participation of phosphorus in chemical evolution. These results allow us to propose a holistic scenario in which an evaporitic environment could concentrate abiotically formed organics and transform the underlying minerals, allowing significant organic phosphorylation under plausible prebiotic conditions. [ABSTRACT FROM AUTHOR]

The poor reactivity of insoluble phosphates, such as apatite-group minerals, has been a long-appreciated obstacle for proposed models of prebiotic organophosphate formation. This obstacle presents a significant challenge to the nascent development of an RNA world and other models for the origins of life on Earth. Herein, we demonstrate that a scenario based on the formation of a urea/ammonium formate/water (UAFW) eutectic solution leads to an increase in phosphorylation when compared to urea alone for phosphate sources of varying solubility. In addition, under evaporative conditions and in the presence of MgSO4, the UAFW eutectic mobilizes the phosphate sequestered in water-insoluble hydroxyapatite, giving rise to a marked increase in phosphorylation. These results suggest that the prebiotic concentrations of urea in a geologically plausible evaporitic environment could solve the problem of organic phosphorylation on a prebiotic Earth. [ABSTRACT FROM AUTHOR]

The poor reactivity of insoluble phosphates, such as apatite-group minerals, has been a long-appreciated obstacle for proposed models of prebiotic organophosphate formation. This obstacle presents a significant challenge to the nascent development of an RNA world and other models for the origins of life on Earth. Herein, we demonstrate that a scenario based on the formation of a urea/ammonium formate/water (UAFW) eutectic solution leads to an increase in phosphorylation when compared to urea alone for phosphate sources of varying solubility. In addition, under evaporative conditions and in the presence of MgSO4, the UAFW eutectic mobilizes the phosphate sequestered in water-insoluble hydroxyapatite, giving rise to a marked increase in phosphorylation. These results suggest that the prebiotic concentrations of urea in a geologically plausible evaporitic environment could solve the problem of organic phosphorylation on a prebiotic Earth. [ABSTRACT FROM AUTHOR]

Chronic venous disease (CVD) is a multifactorial vascular disorder frequently manifested in lower limbs in the form of varicose veins (VVs). Women are a vulnerable population for suffering from CVD, especially during pregnancy, when a plethora of changes occur in their cardiovascular system. Previous studies have indicated a worrisome association between CVD in pregnancy with the placental structure and function. Findings include an altered cellular behavior and extracellular matrix (ECM) composition. Integrin-linked kinase (ILK) is a critical molecule involved in multiple physiological and pathological conditions, and together with cadherins, is essential to mediate cell to ECM and cell to cell interplay, respectively. Thus, the aim of this study was to evaluate the implication of ILK and a set of cadherins (e-cadherin, cadherin-6 and cadherin-17) in placentas of women with CVD in order to unravel the possible pathophysiological role of these components. Gene expression (RT-qPCR) and protein expression (immunohistochemistry) studies were performed. Our results show a significant increase in the gene and protein expression of ILK, cadherin-6 and cadherin-17 and a decrease of e-cadherin in the placenta of women with CVD. Overall, this work shows that an abnormal expression of ILK, e-cadherin, cadherin-6 and cadherin-17 may be implicated in the pathological changes occurring in the placental tissue. Further studies should be conducted to determine the possible associations of these changes with maternal and fetal well-being. [ABSTRACT FROM AUTHOR]

Speciation, an evolutionary process by which new species form, is ultimately responsible for the incredible biodiversity that we observe on Earth every day. Such biodiversity is one of the critical features which contributes to the survivability of biospheres and modern life. While speciation and biodiversity have been amply studied in organismic evolution and modern life, it has not yet been applied to a great extent to understanding the evolutionary dynamics of primitive life. In particular, one unanswered question is at what point in the history of life did speciation as a phenomenon emerge in the first place. Here, we discuss the mechanisms by which speciation could have occurred before the origins of life in the context of chemical evolution. Specifically, we discuss that primitive compartments formed before the emergence of the last universal common ancestor (LUCA) could have provided a mechanism by which primitive chemical systems underwent speciation. In particular, we introduce a variety of primitive compartment structures, and associated functions, that may have plausibly been present on early Earth, followed by examples of both discriminate and indiscriminate speciation affected by primitive modes of compartmentalization. Finally, we discuss modern technologies, in particular, droplet microfluidics, that can be applied to studying speciation phenomena in the laboratory over short timescales. We hope that this discussion highlights the current areas of need in further studies on primitive speciation phenomena while simultaneously proposing directions as important areas of study to the origins of life. [ABSTRACT FROM AUTHOR]

The cover page of the journal "Angewandte Chemie" is presented.

Charles Darwin schwebte 1871 die spontane Bildung biologischer Moleküle “in warmen Tümpeln mit allen möglichen Ammoniak ‐ und Phosphatsalzen” vor. In der Zuschrift auf S. 13443 ff. untersuchen C. Menor ‐ Salván, N. V. Hud et al. die Möglichkeit dieses präbiotischen Szenarios. Wenn sie eine Lösung von Ammoniumformiat, Harnstoff und Epsomit (die gezeigten Magnesiumsulfatkristalle) erhitzten, bildete sich ein Eutektikum, das Phosphat aus unlöslichem Apatit freisetzte, was zur Phosphorylierung von Nucleosiden führte. [ABSTRACT FROM AUTHOR]