scholarly journals Heterogeneous radiolysis of urea. Implications in astrobiology and prebiotic chemistry

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Abigail E. Abigail E. Cruz-Hernández, ◽  
Maria Colin-Garcia ◽  
Alejandro Heredia-Barbero ◽  
Alicia Negron-Mendoza ◽  
Sergio Ramos-Bernal
Keyword(s):  
Organic Molecule ◽  
Prebiotic Chemistry ◽  
Solid Surfaces ◽  
Mineral Surfaces ◽  
Primitive Earth ◽  
High Doses ◽  
Living Organisms ◽  
Life On Earth ◽  
Emergence Of Life

AbstractUrea is an organic molecule present in most living organisms. Historically, it was the first organic molecule synthesized in the laboratory. In prebiotic chemistry, urea readily forms in different laboratory simulations using different energy sources. Furthermore, the role of solid surfaces, particularly minerals, might have been crucial to increase the complexity of the organic matter which may have led to the subsequent emergence of life on Earth. In this work, the radiolysis of urea in presence of a clay is studied to determine to what extent the mineral surfaces influence the decomposition of organics. The results indicate that urea is relatively stable to ionizing radiation in aqueous solutions and up to 20 kGy no decomposition is observed. Moreover, the presence of sodium montmorillonite, by a mechanism until now unknown, affects the radiolytic behavior and urea remains in the heterogeneous solution without a change in concentration even at very high doses (140 kGy). These results indicate that solids could have protected some organics, like urea, from degradation enabling them to remain in the environment on the primitive Earth.

scholarly journals Biocrystals in Plants: A Short Review on Biomineralization Processes and the Role of Phototropins into the Uptake of Calcium

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 591 ◽  
Author(s):  
Mayra Cuéllar-Cruz ◽  
Karina Sandra Pérez ◽  
María Eugenia Mendoza ◽  
Abel Moreno
Keyword(s):  
Calcium Uptake ◽  
Homo Sapiens ◽  
Short Review ◽  
Inorganic Materials ◽  
Organic Crystals ◽  
Biomineralization Process ◽  
The Origin Of Life ◽  
Living Organisms ◽  
Life On Earth

The biomineralization process is a mechanism inherent to all organisms of the Earth. Throughout the decades, diverse works have reported that the origin of life is tied to crystals, specifically to biominerals of silica that catalyzed RNA, and had some influence in the homochirality. Although the mechanism by which crystals surfaces (minerals) gave origin to life has not yet been proven, the truth is that, up to the present, biominerals are being synthetized by the organisms of different kingdoms in two basic ways: biologically induced and biologically controlled biomineralization. Paradoxically, this fact makes a fundamental difference between inorganic materials and those formed by living organisms, as the latter are associated with macromolecules that are bound to the mineral phase. Conserving growth and formation of these biogenic organic crystals inside cells is a fascinating subject that has been studied mainly in some of the kingdoms, like Monera (bacteria), Fungi (yeasts), and Animalia (Homo sapiens). Notwithstanding in the Plantae kingdom, the formation, conservation, and functions of crystals has not yet been completely elucidated and described, which is of particular relevance because life on Earth, as we know it, would not be possible without plants. The aim of the present work is to revise the different crystals of calcium oxalate synthetized inside the cells of plants, as well as to identify the mechanism of their formation and their possible functions in plants. The last part is related to the existence of certain proteins called phototropins, which not only work as the blue-light sensors, but they also play an important role on the accumulation of calcium in vacuoles. This new trend is shortly reviewed to explain the characteristics and their plausible role in the calcium uptake along with the biomineralization processes.

scholarly journals Genome Tree of Life: Deep Burst of Organism Diversity

2019 ◽  
Author(s):  
JaeJin Choi ◽  
Sung-Hou Kim
Keyword(s):  
Genome Sequence ◽  
Tree Of Life ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
A Genome ◽  
Living Organisms ◽  
Life On Earth ◽  
Large Groups ◽  
Emergence Of Life ◽  
Genome Tree

AbstractAn organism Tree of Life (organism ToL) is a conceptual and metaphorical tree to capture a simplified narrative of the evolutionary course and kinship among the extant organisms of today. Such tree cannot be experimentally validated but may be reconstructed based on characteristics associated with the extant organisms. Since the whole genome sequence of an organism is, at present, the most comprehensive descriptor of the organism, a genome Tol can be an empirically derivable surrogate for the organism ToL. However, a genome ToL has been impossible to construct because of the practical reasons that experimentally determining the whole genome sequences of a large number of diverse organisms was technically impossible. Thus, for several decades, gene ToLs, based on selected genes, have been commonly used as a surrogate for the organisms ToL. This situation changed dramatically during the last several decades due to rapid advances in DNA sequencing technology. Here we describe the main features of a genome ToL that are different from those of the broadly accepted gene ToLs: (a) the first two organism groups to emerge are the founders of prokarya and eukarya, (b) they diversify into six large groups and all the founders of the groups have emerged in a “Deep Burst” at the very beginning period of the emergence of Life on Earth and (c) other differences are notable in the order of emergence of smaller groups.Significance StatementTree of Life is a conceptual and metaphorical tree that captures a simplified narrative of the evolutionary course and kinship among all living organisms of today. Since the whole genome sequence information of an organism is, at present, the most comprehensive description of the organism, we reconstructed a Genome Tree of Life using the proteome information from the whole genomes of over 4000 different living organisms on Earth. It suggests that (a) the first two primitive organism groups to emerge are the founders of prokarya and eukarya, (b) they diversify into six large groups, and (c) all the founders of the groups have emerged in a “Deep Burst” at the very beginning period of the emergence of Life on Earth.

scholarly journals A Lizardite–HCN Interaction Leading the Increasing of Molecular Complexity in an Alkaline Hydrothermal Scenario: Implications for Origin of Life Studies

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 661
Author(s):  
Saúl A. Villafañe-Barajas ◽  
Marta Ruiz-Bermejo ◽  
Pedro Rayo-Pizarroso ◽  
Santos Gálvez-Martínez ◽  
Eva Mateo-Martí ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Hydrogen Cyanide ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Analytical Techniques ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Molecular Complexity ◽  
Molecule Production

Hydrogen cyanide, HCN, is considered a fundamental molecule in chemical evolution. The named HCN polymers have been suggested as precursors of important bioorganics. Some novel researches have focused on the role of mineral surfaces in the hydrolysis and/or polymerization of cyanide species, but until now, their role has been unclear. Understanding the role of minerals in chemical evolution processes is crucial because minerals undoubtedly interacted with the organic molecules formed on the early Earth by different process. Therefore, we simulated the probable interactions between HCN and a serpentinite-hosted alkaline hydrothermal system. We studied the effect of serpentinite during the thermolysis of HCN at basic conditions (i.e., HCN 0.15 M, 50 h, 100 °C, pH > 10). The HCN-derived thermal polymer and supernatant formed after treatment were analyzed by several complementary analytical techniques. The results obtained suggest that: I) the mineral surfaces can act as mediators in the mechanisms of organic molecule production such as the polymerization of HCN; II) the thermal and physicochemical properties of the HCN polymer produced are affected by the presence of the mineral surface; and III) serpentinite seems to inhibit the formation of bioorganic molecules compared with the control (without mineral).

scholarly journals How the Geomagnetic Field Influences Life on Earth – An Integrated Approach to Geomagnetobiology

2021 ◽  
Author(s):  
Weronika Erdmann ◽  
Hanna Kmita ◽  
Jakub Z. Kosicki ◽  
Łukasz Kaczmarek
Keyword(s):  
Solar Wind ◽  
Geomagnetic Field ◽  
Spatial Information ◽  
Positive Impact ◽  
Current Knowledge ◽  
Integrated Approach ◽  
Short Term ◽  
Living Organisms ◽  
Life On Earth ◽  
Emergence Of Life

AbstractEarth is one of the inner planets of the Solar System, but – unlike the others – it has an oxidising atmosphere, relatively stable temperature, and a constant geomagnetic field (GMF). The GMF does not only protect life on Earth against the solar wind and cosmic rays, but it also shields the atmosphere itself, thus creating relatively stable environmental conditions. What is more, the GMF could have influenced the origins of life: organisms from archaea to plants and animals may have been using the GMF as a source of spatial information since the very beginning. Although the GMF is constant, it does undergo various changes, some of which, e.g. a reversal of the poles, weaken the field significantly or even lead to its short-term disappearance. This may result in considerable climatic changes and an increased frequency of mutations caused by the solar wind and cosmic radiation. This review analyses data on the influence of the GMF on different aspects of life and it also presents current knowledge in the area. In conclusion, the GMF has a positive impact on living organisms, whereas a diminishing or disappearing GMF negatively affects living organisms. The influence of the GMF may also be an important factor determining both survival of terrestrial organisms outside Earth and the emergence of life on other planets.

Possible role of Prussian blue nanoparticles in chemical evolution: interaction with ribose nucleotides

2015 ◽  
Vol 15 (1) ◽  
pp. 17-25
Author(s):  
Rachana Sharma ◽  
Md. Asif Iqubal ◽  
Kamaluddin
Keyword(s):  
Prussian Blue ◽  
Genetic Material ◽  
Building Blocks ◽  
Mineral Surfaces ◽  
Primitive Earth ◽  
Prussian Blue Nanoparticles ◽  
Group A ◽  
Pseudo Second Order ◽  
Langmuir Constants

AbstractRibonucleotides (RMPs) are the building blocks of genetic material consisting of a sugar group, a phosphate group and a nucleobase. Prussian blue (PB) is an ancient compound which is supposed to have formed under the conditions of primitive Earth. The interaction between nucleotides and mineral surfaces is of primary importance in the context of prebiotic chemistry. In the present work, the adsorption of RMPs on PB has been studied in the concentration range 0.4 × 10−4–3.0 × 10−4 M of RMPs at pH 7.5, T = 27°C and found to be 53.1, 41.7, 25.8 and 24.0% for adenosine 5′-monophosphate (5′-AMP), guanosine 5′-monophosphate, cytidine 5′-monophosphate and uridine 5′-monophosphate, respectively. Optimum conditions for the adsorption were studied as a function of concentration, time, amount of adsorbent and pH and data obtained were found to fit the Langmuir adsorption isotherm. Langmuir constants (KL and Xm) values were calculated. Fourier transform infrared spectroscopy, Raman spectroscopy, field-emission scanning electron microscopy and X-ray diffractometry techniques were used to investigate the interaction of RMPs on PB surface. Adsorption kinetics of 5′-AMP on PB has been found to be pseudo-second order. Results obtained from this study should prove valuable for a better understanding of the mechanism of RMP–PB interaction.

Dynamics of bioenergetic microcompartments

2013 ◽  
Vol 394 (2) ◽  
pp. 163-188 ◽  
Author(s):  
Karin B. Busch ◽  
Gabriele Deckers-Hebestreit ◽  
Guy T. Hanke ◽  
Armen Y. Mulkidjanian
Keyword(s):  
Energy Loss ◽  
Protein Complexes ◽  
Electron Flow ◽  
Atp Generation ◽  
Membrane Protein Complexes ◽  
Electron Transfer Pathways ◽  
Living Organisms ◽  
Life On Earth ◽  
Energy Converting

Abstract The vast majority of life on earth is dependent on harvesting electrochemical potentials over membranes for the synthesis of ATP. Generation of membrane potential often relies on electron transport through membrane protein complexes, which vary among the bioenergetic membranes found in living organisms. In order to maximize the efficient harvesting of the electrochemical potential, energy loss must be minimized, and this is achieved partly by restricting certain events to specific microcompartments, on bioenergetic membranes. In this review we will describe the characteristics of the energy-converting supramolecular structures involved in oxidative phosphorylation in mitochondria and bacteria, and photophosphorylation. Efficient function of electron transfer pathways requires regulation of electron flow, and we will also discuss how this is partly achieved through dynamic re-compartmentation of the membrane complexes into different supercomplexes. In addition to supercomplexes, the supramolecular structure of the membrane, and in particular the role of water layers on the surface of the membrane in the prevention of wasteful proton escape (and therefore energy loss), is discussed in detail. In summary, the restriction of energetic processes to specific microcompartments on bioenergetic membranes minimizes energy loss, and dynamic rearrangement of these structures allows for regulation.

scholarly journals Neopanspermia – Evidence That Life Continuously Arrives at the Earth from Space

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Milton Wainwright ◽  
◽  
N. Chandra Wickramasinghe ◽  
Gensuke Tokoro ◽  
◽  
...  
Keyword(s):  
Fungal Spores ◽  
Pollen Grains ◽  
Bilateral Symmetry ◽  
Primitive Earth ◽  
The Earth ◽  
Habitable Zones ◽  
Order Of Magnitude ◽  
Life On Earth ◽  
Biological Entities ◽  
Emergence Of Life

The theory of panspermia in a variety of forms remains an important theory to account for the origin of life on Earth and possibly also on other planetary bodies orbiting the “habitable zones” of stars. A form of panspermia we review here, that can be called neopanspermia, encapsulates the concept that a continuing infall of microbiota from space contributes both to the inception of life on Earth and its subsequent evolution. We discuss the development of the theory of panspermia and show how, over the past decade, we have used balloon-borne samplers (lofted to heights approaching 30km) to isolate unusual Biological Entities (BEs) which, we maintain, are continuously arriving at the Earth from space. These BEs are carbon-based, show bilateral symmetry, contain DNA and are in the range 10-40 micrometres in dimension. Their sizes are an order of magnitude higher than par-ticles (including bacteria and viruses) of terrestrial origin that are normally recovered in the strato-sphere. The fact that Earth-organisms (e.g. pollen grains, grass-shards and fungal spores) have not been found in our samples provides additional evidence that the isolated BEs originate from space and are of extraterrestrial provenance. We propose that such incoming microorganisms led to the emergence of life on the primitive Earth between 3.83 and 4 billion years ago and thereafter have continuously contributed to its evolution.

Collagen-Induced Platelet Aggregation: -Evidence Against the Essential Role of Platelet Adenosine Diphosphate

1979 ◽  
Vol 42 (04) ◽  
pp. 1193-1206 ◽  
Author(s):  
Barbara Nunn
Keyword(s):  
Platelet Aggregation ◽  
Time Course ◽  
Essential Role ◽  
Atp Release ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
High Doses ◽  
Induced Aggregation

SummaryThe hypothesis that platelet ADP is responsible for collagen-induced aggregation has been re-examined. It was found that the concentration of ADP obtaining in human PRP at the onset of aggregation was not sufficient to account for that aggregation. Furthermore, the time-course of collagen-induced release in human PRP was the same as that in sheep PRP where ADP does not cause release. These findings are not consistent with claims that ADP alone perpetuates a collagen-initiated release-aggregation-release sequence. The effects of high doses of collagen, which released 4-5 μM ADP, were not inhibited by 500 pM adenosine, a concentration that greatly reduced the effect of 300 μM ADP. Collagen caused aggregation in ADP-refractory PRP and in platelet suspensions unresponsive to 1 mM ADP. Thus human platelets can aggregate in response to collagen under circumstances in which they cannot respond to ADP. Apyrase inhibited aggregation and ATP release in platelet suspensions but not in human PRP. Evidence is presented that the means currently used to examine the role of ADP in aggregation require investigation.

Multiple interactions in riverine biofilms - surfactant adsorption, bacterial attachment and biodegradation

1995 ◽  
Vol 31 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Graham F. White
Keyword(s):  
Organic Pollutants ◽  
Bacterial Attachment ◽  
Solid Surfaces ◽  
Sediment Surface ◽  
Liquid Interfaces ◽  
Polluted Soils ◽  
Biofilm Bacteria ◽  
The Impact ◽  
Multiple Interactions

Many organic pollutants, especially synthetic surfactants, adsorb onto solid surfaces in natural and engineered aquatic environments. Biofilm bacteria on such surfaces make major contributions to microbial heterotrophic activity and biodegradation of organic pollutants. This paper reviews evidence for multiple interactions between surfactants, biodegradative bacteria, and sediment-liquid interfaces. Biodegradable surfactants e.g. SDS, added to a river-water microcosm were rapidly adsorb to sediment surface and stimulated the indigenous bacteria to attach to the sediment particles. Recalcitrant surfactants and non-surfactant organic nutrients did not stimulate attachment Attachment of bacteria was maximal when biodegradation was fastest, and was reversed when biodegradation was complete. Dodecanol, the primary product of SDS-biodegradation, markedly stimulated attachment. When SDS was added to suspensions containing sediment and either known degraders or known non-degraders, only the degraders became attached, and attachment accelerated surfactant biodegradation to dodecanol. These cyclical cooperative interactions have implications for the design of biodegradability-tests, the impact of surfactant adjuvants on biodegradability of herbicides/pesticides formulated with surfactants, and the role of surfactants used to accelerate bioremediation of hydrocarbon-polluted soils.

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