Cesar Menor Salvan

University of Alcalá | UAH · Department of Physiology, Biochemistry and Molecular Biology

Malononitrile (C3H2N2) is a highly reactive compound that plays an important role in the synthesis of heterocyclic compounds and may have contributed to the formation of nucleobases and nucleosides in a pre-RNA world. Despite its significance in prebiotic chemistry and potential implications in astrobiology, its possible synthesis has not yet been...

This PDF contains the extensive Supplementary Data of the paper "Amber and the Cretaceous Resinous Event" at the end of it

THE PAPER IS IN OPEN ACCESS IN THE URL: https://doi.org/10.1016/j.earscirev.2023.104486 Amber is fossilized resin that preserves biological remains in exceptional detail, study of which has revolutionized understanding of past terrestrial organisms and habitats from the Early Cretaceous to the present day. Cretaceous amber outcrops are more abund...

The formose reaction is a plausible prebiotic chemistry, famed for its production of sugars. In this work, we demonstrate that the Cannizzaro process is the dominant process in the formose reaction under many different conditions, thus necessitating a catalyst for the formose reaction under various environmental circumstances. The investigated form...

Context. Cyanamide (NH 2 CN) and its tautomer carbodiimide (NHCHN) are believed to have been key precursors of purines and pyrimidines during abiogenesis on primitive Earth. The detection of guanine and cytosine in meteorites and comets provides evidence of their nonterrestrial formation. Although NH 2 CN has been found in several molecular clouds,...

Establishing plausible routes for the abiotic formation of nucleotides is a challenging problem because the phosphorylation of organic molecules is thermodynamically unfavorable in water, and because common phosphorous‐containing minerals such as apatite are highly insoluble. Reactions of reduced phases such as the meteoritic mineral schreibersite...

The prebiotic origins of ribose, nucleosides, and eventually RNA are enduring questions whose answers are central to the RNA World hypothesis. The abiotic synthesis of sugars was first demonstrated over a century ago, but no known prebiotic reaction produces ribose (an aldose sugar) selectively and in good yield. In contrast, ribulose and fructose...

Guanosine and pterins are depicted as the constellation Gemini. Guanine nucleosides are one of the immortal survivors of prebiotic chemistry, becoming the focus of many prebiotic reactions. 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) pa...

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...

The prebiotic origins of biopolymers and metabolic co‐factors are key questions in Origins of Life studies. In a simple warm little pond model, utilizing 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 s...

Background: Recently, increased tissue levels of AIF-1 have been shown in experimental colitis, supporting its role in intestinal inflammation. Therefore, we studied the levels of AIF-1 in Crohn's disease (CD). Methods: This study included 33 patients with CD (14 men and 19 women) who participated in the PREDICROHN project, a prospective multice...

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 b...

Sierra Aznar situada junto al río Majaceite, en territorio intermedio entre la campiña y la serranía, es conocida principalmente como yacimiento arqueológico de época romana. Destacan las construcciones relacionadas con el aprovechamiento del recurso natural hídrico de la sierra. Las investigaciones de nuestro proyecto comprenden la secuencia diacr...

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 dinosau...

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...

ABSTRACT Context. Formaldehyde is a potential biogenic precursor involved in prebiotic chemical evolution. The cold conditions of the inter�stellar medium (ISM) allow H2CO to be reactive, playing a significant role as a chemical intermediate in formation pathways leading to interstellar complex organic molecules. However, gas-phase molecular format...

Centimeter-sized crystals of orthorhombic calcium formate, α-Ca(HCO2)2 from Alkali Lake, Oregon, USA have been studied by means of powder and single-crystal X-ray diffraction analysis, infrared, and Raman spectroscopy. Based on the data on carbon isotope abundance in calcium formate and associated minerals, it was concluded that the formation of α-...

The former lignite pits of the Geiseltal in Saxony-Anhalt, Germany, were an important source of well-preserved Eocene animal and plant fossil remains, including resinites (fossil resins) from different botanical sources. We studied three different types of resinites with distinct morphological characteristics, collected at one of the Geiseltal pits...

Urea appears to be a key intermediate of important prebiotic synthetic pathways. Concentrated pools of urea likely existed on the surface of the early Earth, as urea is synthesized in significant quantities from hydrogen cyanide or cyanamide (widely accepted prebiotic molecules), it has extremely high water solubility, and it can concentrate to for...

Sugars are essential for the formation of genetic elements such as RNA and as an energy/food source. Thus, the formose reaction, which autocatalytically generates a multitude of sugars from formaldehyde, has been viewed as a potentially important prebiotic source of biomolecules at the origins of life. When analyzing our formose solutions we find t...

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—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 t...

Eisen und Cyanid: Cyanid könnte als geochemisches Reagens in der präbiotischen Phosphorylierung eine Rolle gespielt haben. Cyanid und seine Metallkomplexe können Phosphat aus unlöslichen Eisen- und Calcium-Mineralien transformieren und herauslösen, was darauf hindeutet, dass auf der frühen Erde Phosphat mobiler und präbiotische Phosphorylierung ein...

Urea is formed in significant quantities in classic prebiotic model reactions and simply by hydrolysis of cyanide. It is a very interesting molecule, with chemical properties that make it a potential precursor of nucleobases and related molecules, as well as a promoter of phosphorylation. In addition, urea’s physico-chemical properties allow it to...

The origin of life is one of the biggest unsolved scientific questions. This book deals with the formation and first steps of the chemical evolution of nucleic acids, including the chemical roots behind the origin of their components from the simplest sources in a geochemical context. Chemical evolution encompasses the chemical processes and intera...

Uniform iron oxide magnetic nanoparticles have been synthesized using a microwave assisted synthesis method in organic media and their colloidal, magnetic, and relaxometric properties have been analyzed after its transference to water and compared with those nanoparticles prepared by thermal decomposition in organic media. The novelty of this synth...

Figure S1. GC-MS trace (total ion chromatogram) of the methylated fatty acid composition of the solid iron oleate (A) and liquid iron oleate (B). Table S1. Fatty acid composition of synthesized iron oleates. Figure S2. X-ray diffraction pattern for liquid iron oleate. Figure S3. TEM image of solid iron oleate, where a hydrophobized hydroxide nanoma...

There is an increasing need for the development of simple, rapid and sustainable techniques to control quality of olive oils, ensure geographical origin and fight against adulterant agents and label frauds. Also it would be desirable to rapidly assess the amount of degradation of olive oils in food industry processes for food safety issues. Leaving...

Accumulated evidences suggest an early role of urea-derived non-canonical nucleobases in RNA chemical evolution. In this conference we presented our initial results on the prebiotic synthesis of pyrimidines of the barbituric acid family and purines in a urea-rich environment. We showed that urea and malonic acid could be condensed by drying-rewetti...

Resumen: La atmósfera que respiramos actualmente es el resultado de un proceso de cambios e interacciones en el que la geología, la entra-da de objetos extraterrestres y el nacimiento y evolución de la vida han jugado un papel esencial. En este artículo resumimos el conocimiento sobre el origen y la evolución de la composición de la atmósfera del p...

Raman spectroscopy studies have been performed on the one hand to identify different materials related to spent nuclear fuel (SNF), and on the other hand to study the behavior of SNF at different storage conditions. Specifically, the expected oxidation of the SNF matrix under dry storage conditions and the formation of secondary phases (SP), as a r...

Raman spectroscopy is a non-destructive, fast and reliable technique for the identification of the desloizite group of lead vanadates. Mineral and non-natural member of this group have published and described spectra, except in the case of cechite, a rare lead and iron vanadate mineral, first described in samples from Alexander mine and the Posepny...

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 scena...

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 scena...

Charles Darwin schwebte 1871 die spontane Bildung biologischer Moleküle „in warmen Tümpeln mit allen möglichen Ammoniak- und Phosphatsalzen” vor. In ihrer Zuschrift (DOI: 10.1002/ange.201606239) untersuchen C. Menor-Salvan, N. V. Hud et al. die Möglichkeit dieses präbiotischen Szenarios. Wenn sie eine Lösung von Ammoniumformiat, Harnstoff und Epsom...

In 1871, Charles Darwin envisioned the spontaneous formation of biological molecules “in some warm little pond with all sort of ammonia and phosphoric salts”. C. Menor-Salvan, N. V. Hud, and co-workers tested the feasibility of this prebiotic scenario as described in their Communication (DOI: 10.1002/anie.201606239). When a solution containing ammo...

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 re...

Uraninite is a mineral considered as an analogue of the spent fuel, and the study of its alteration products has been used to predict the secondary phases produced during the fuel storage under specific environmental conditions. In this work, we study by Raman spectroscopy the alteration by weathering of the primary uraninite from the uranium depos...

Las Cruces is a base-metal deposit in the Iberian Pyrite Belt, one of the world's best-known ore provinces. Here we report the occurrence of major Pb-Ag-Au mineralization resulting from recent sub-surface replacement of supergene oxyhydroxides by carbonate and sulphide minerals. This is probably the largest documented occurrence of recent microbial...

We study the bias induced by a weak (200 mT) external magnetic field on the preferred handedness of sodium chlorate crystals obtained by slow evaporation at ambient conditions of its saturated saline solution with 20 ppm of added racemic (dl) hydrophobic amino acids. By applying the Fisher test to pairs of experiments with opposing magnetic field o...

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...

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...

This study presents the thermogravimetry (TG) of hydrophobic tholins, obtained from different simulation experiments of prebiotic synthesis carried out in a CH4/N2/H2 atmosphere with spark discharge activation of aqueous aerosols and liquid water. Differential thermal analysis and differential scanning calorimetry were also used to evaluate the the...

The theory of the chemo-autotrophic origin of life, also called the "iron-sulfur world hypothesis", proposes that the system FeS/FeS2 present in the primitive Earth crust gave the reductive power necessary to conduct the first protometabolic redox reactions. Some experimental studies demonstrated the redox activity of the FeS/SH2 system, but none o...

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 cha...

A crystalline ice matrix at subzero temperatures can maintain a liquid phase where organic solutes and salts concentrate to form eutectic solutions. This concentration effect converts the confined reactant solutions in the ice matrix, sometimes making condensation and polymerisation reactions occur more favourably. These reactions occur at signific...

The data presented here provide a novel contribution to the understanding of the structural features of HCN polymers and could be useful in further development of models for prebiotic chemistry. The interpretation of spectroscopic and analytical data, along with previous results reported by other authors, allowed us to propose a mechanism for the a...

Some terrestrial areas have favourable environmental features that allow the preservation and scientific study of processes which can be used as geomarkers. The crater-like Richat structure (Sahara desert, Mauritania) is a recently proposed protected natural area, which can be considered as one of these sites. Volcanic, hydrothermal and arid enviro...

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...

The particular mineralogy formed in the acidic conditions of the Río Tinto has proven to be a first-order analogue for the acid-sulfate aqueous environments of Mars. Therefore, studies about the formation and preservation of biosignatures in the Río Tinto will provide insights into equivalent processes on Mars. We characterized the biomolecular pat...

Clasically, prebiotic chemistry has focused on the production and identification of simple organic molecules, many of them forming part of "intractable polymers" named tholins. In a previous work, we demonstrated that in experiments using an external energy source and inorganic carbon the aqueous aerosols improved the formation of hydrophilic tholi...

The Iberian Pyrite Belt (SW Iberia) is one of the largest sulfur anomalies in the Earth's crust. In the southern Iberian Pyrite Belt, more than 820Mt of exhalative massive sulfides were deposited in less than one million years at the Devonian–Carboniferous boundary. The shale of the ore-bearing horizon contains biomarkers indicating major biogenic...

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 pre...

: El Soplao outcrop, an Early Cretaceous amber deposit recently discovered in northern Spain (Cantabria), has been shown to be the largest site of amber with arthropod inclusions that has been found in Spain so far. Relevant data provided herein for biogeochemistry of the amber, palynology, taphonomy and arthropod bioinclusions complement those pre...

Thermochemical calculations of gas/fluid speciation in submarine hydrothermal fluids and volcanic gas suggest the pre-biotic atmosphere was methane rich and strongly reducing. This supports the Urey-Miller model for the origin of life.

The aim of this work is to investigate the fate of organic molecules, which were synthesized in methane-rich atmospheres by spark discharges, in Fe2+-rich aqueous solutions.

El Soplao outcrop, an Early Cretaceous amber deposit recently discovered in northern Spain (Cantabria), has been shown to be the largest site of amber with arthropod inclusions that has been found in Spain so far. Relevant data provided herein for biogeochemistry of the amber, palynology, taphonomy and arthropod bioinclusions complement those previ...

Prebiotic chemistry studies the possible origins of the building blocks of living organisms, as well as their chirality. The hypothesis commonly accepted to explain the origin of life is that simple inorganic molecules, for instance, CH4, CO2, N2, NH3, reacted together in order to form simple organic compounds that then underwent subsequent reactio...

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,...