Formamide-based synthesis of nucleobases by metal(II) octacyanomolybdate(IV): implication in prebiotic chemistry

Quantum Dots in Peroxidase-like Chemistry and Formamide-Based Hot Spring Synthesis of Nucleobases

Quantum dots (QDs) are usually seen as artificial semiconductor particles exhibiting optical and electronic properties interesting for nanotechnological applications. However, they may also play a role in prebiotic chemistry. Starting from zinc acetate, cadmium acetate, and mercaptosuccinic acid, we demonstrate the formation of ZnCd QDs upon UV irradiation in prebiotic liquid formamide. We show that ZnCd QDs are able to increase the yield of RNA nucleobase synthesis from formamide up to 300 times, suggesting they might have served as universal catalysts in a primordial milieu. Based on the experimentally observed peroxidase-like activity of ZnCd QDs upon irradiation with visible light, we propose that QDs could be relevant to a broad variety of processes relating to the emergence of terrestrial life.

Chirality in Organic and Mineral Systems: A Review of Reactivity and Alteration Processes Relevant to Prebiotic Chemistry and Life Detection Missions

Chirality is a central feature in the evolution of biological systems, but the reason for biology’s strong preference for specific chiralities of amino acids, sugars, and other molecules remains a controversial and unanswered question in origins of life research. Biological polymers tend toward homochiral systems, which favor the incorporation of a single enantiomer (molecules with a specific chiral configuration) over the other. There have been numerous investigations into the processes that preferentially enrich one enantiomer to understand the evolution of an early, racemic, prebiotic organic world. Chirality can also be a property of minerals; their interaction with chiral organics is important for assessing how post-depositional alteration processes could affect the stereochemical configuration of simple and complex organic molecules. In this paper, we review the properties of organic compounds and minerals as well as the physical, chemical, and geological processes that affect organic and mineral chirality during the preservation and detection of organic compounds. We provide perspectives and discussions on the reactions and analytical techniques that can be performed in the laboratory, and comment on the state of knowledge of flight-capable technologies in current and future planetary missions, with a focus on organics analysis and life detection.

Role of the Interchangeable Cations on the Sorption of Fumaric and Succinic Acids on Montmorillonite and its Relevance in Prebiotic Chemistry

It has been proposed that clays could have served as key factors in promoting the increase in complexity of organic matter in primitive terrestrial and extraterrestrial environments. The aim of this work is to study the adsorption-desorption of two dicarboxylic acids, fumaric and succinic acids, onto clay minerals (sodium and iron montmorillonite). These two acids may have played a role in prebiotic chemistry, and in extant biochemistry, they constitute an important redox couple (e.g. in Krebs cycle) in extant biochemistry. Smectite clays might have played a key role in the origins of life. The effect of pH on sorption has been tested; the analysis was performed by UV-vis and FTIR-ATR spectroscopy, X-ray diffraction and X-ray fluorescence. The results show that chemisorption is the main responsible of the adsorption processes among the dicarboxylic acids and clays. The role of the ion, present in the clay, is fundamental in the adsorption processes of dicarboxylic acids. These ions (sodium and iron) were selected due to their relevance on the geochemical environments that possibly existed into the primitive Earth. Different mechanisms are proposed to explain the sorption of dicarboxylic acids in the clay. In this work, we propose the formation of complexes among metal cations in the clays and dicarboxylic acids. The organic complexes were probably formed in the prebiotic environments enabling chemical processes, prior to the appearance of life. Thus, the data presented here are relevant to the origin of life studies.

Prebiotic Organic Chemistry of Formamide and the Origin of Life in Planetary Conditions: What We Know and What Is the Future

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.

Elucidation of metabolic responses in mud crab Scylla paramamosain challenged to WSSV infection by integration of metabolomics and transcriptomics

White spot syndrome virus (WSSV) is a severe pathogen of mud crab Scylla paramamosain (S. paramamosain). Hemolymph, containing three types of hemocytes, is the key immunoregulatory tool of mud crab in response to pathogens. Herein, the metabonomics and transcriptomics analysis of hemocytes were adopted to investigate the immune response of S. paramamosain challenged to WSSV. We established the metabolic and transcriptional profiles of mud crab hemocytes with different treatments, including the control group (WT), WSSV early infected group (WSSV-6 h) and WSSV later infected group (WSSV-72 h). The results showed that 68 metabolites were dysregulated both in WSSV-infected mud crab of early stage and later stage, while 4452 genes were up-regulated and 9746 genes were down-regulated in WSSV-6 h, and 2016 genes were up-regulated and 6229 genes were down-regulated compared in WSSV-72 h. We found that several pathways were dysregulated at both metabolic and transcriptional levels, including ABC transporters, purine metabolism, taurine and hypotaurine metabolism in the WSSV early infected group, cysteine metabolism, methionine metabolism and biosynthesis of unsaturated fatty acids in the WSSV later infected group. In this context, through the integration of metabolomics and transcriptomics, our study provided a more comprehensive understanding of the biological process in mud crab against viral invasion.

Synthesis of Nucleic Acid Bases by Metal Ferrite Nanoparticles from a Single Carbon Atom Precursor Molecule: Formamide

The synthesis of prebiotic molecules from simple precursors is believed to be a crucial scheme in order to study the origin of life processes. The present study describes the one-pot synthesis of purine and pyrimidine nucleic acid bases in the presence of pre-biologically significant binary metal oxide nanoparticles, metal ferrites, namely NiFe2O4, CoFe2O4, CuFe2O4, ZnFe2O4 and MnFe2O4. The products identified are cytosine, isocytosine, 4(3H)-pyrimidinone, adenine, hypoxanthine and purine. The ability of isocytosine (a constitutional isomer of cytosine) to recognize cytosine and guanine through normal and reversed Watson-Crick pairing respectively, demonstrates an important storyline for the genesis of ancient nucleic acids. The relevance of other synthesized nucleic acid bases with respect to the origin of life is also discussed. The divalent metal ions in iron oxide make it an appropriate catalytic system because it demonstrates excellent catalytic performance for the nucleic acid bases synthesis with significantly high yield, as compared to pure iron oxide and some other minerals like silica, alumina, manganese oxides and double metal cyanide complexes.

P2Y Receptors in Immune Response and Inflammation

Metabotropic pyrimidine and purine nucleotide receptors (P2Y receptors) are expressed in virtually all cells with implications in very diverse biological functions, including the well-established platelet aggregation (P2Y12), but also immune regulation and inflammation. The classical P2Y receptors bind nucleotides and are encoded by eight genes with limited sequence homology, while phylogenetically related receptors (e.g., P2Y12-like) recognize lipids and peptides, but also nucleotide derivatives. Growing lines of evidence suggest an important function of P2Y receptors in immune cell differentiation and maturation, migration, and cell apoptosis. Here, we give a perspective on the P2Y receptors' molecular structure and physiological importance in immune cells, as well as the related diseases and P2Y-targeting therapies. Extensive research is being undertaken to find modulators of P2Y receptors and uncover their physiological roles. We anticipate the medical applications of P2Y modulators and their immune relevance.

Purinergic regulation of the immune system

Cellular stress or apoptosis triggers the release of ATP, ADP and other nucleotides into the extracellular space. Extracellular nucleotides function as autocrine and paracrine signalling molecules by activating cell-surface P2 purinergic receptors that elicit pro-inflammatory immune responses. Over time, extracellular nucleotides are metabolized to adenosine, leading to reduced P2 signalling and increased signalling through anti-inflammatory adenosine (P1 purinergic) receptors. Here, we review how local purinergic signalling changes over time during tissue responses to injury or disease, and we discuss the potential of targeting purinergic signalling pathways for the immunotherapeutic treatment of ischaemia, organ transplantation, autoimmunity or cancer.