Organic compounds in fluid inclusions of Archean quartz-Analogues of prebiotic chemistry on early Earth.

PubMed

Schreiber, Ulrich; Mayer, Christian; Schmitz, Oliver J; Rosendahl, Pia; Bronja, Amela; Greule, Markus; Keppler, Frank; Mulder, Ines; Sattler, Tobias; Schöler, Heinz F

2017-01-01

The origin of life is still an unsolved mystery in science. Hypothetically, prebiotic chemistry and the formation of protocells may have evolved in the hydrothermal environment of tectonic fault zones in the upper continental crust, an environment where sensitive molecules are protected against degradation induced e.g. by UV radiation. The composition of fluid inclusions in minerals such as quartz crystals which have grown in this environment during the Archean period might provide important information about the first organic molecules formed by hydrothermal synthesis. Here we present evidence for organic compounds which were preserved in fluid inclusions of Archean quartz minerals from Western Australia. We found a variety of organic compounds such as alkanes, halocarbons, alcohols and aldehydes which unambiguously show that simple and even more complex prebiotic organic molecules have been formed by hydrothermal processes. Stable-isotope analysis confirms that the methane found in the inclusions has most likely been formed from abiotic sources by hydrothermal chemistry. Obviously, the liquid phase in the continental Archean crust provided an interesting choice of functional organic molecules. We conclude that organic substances such as these could have made an important contribution to prebiotic chemistry which might eventually have led to the formation of living cells.

Prebiotic synthesis of phosphoenol pyruvate by α-phosphorylation-controlled triose glycolysis

NASA Astrophysics Data System (ADS)

Coggins, Adam J.; Powner, Matthew W.

2017-04-01

Phosphoenol pyruvate is the highest-energy phosphate found in living organisms and is one of the most versatile molecules in metabolism. Consequently, it is an essential intermediate in a wide variety of biochemical pathways, including carbon fixation, the shikimate pathway, substrate-level phosphorylation, gluconeogenesis and glycolysis. Triose glycolysis (generation of ATP from glyceraldehyde 3-phosphate via phosphoenol pyruvate) is among the most central and highly conserved pathways in metabolism. Here, we demonstrate the efficient and robust synthesis of phosphoenol pyruvate from prebiotic nucleotide precursors, glycolaldehyde and glyceraldehyde. Furthermore, phosphoenol pyruvate is derived within an α-phosphorylation controlled reaction network that gives access to glyceric acid 2-phosphate, glyceric acid 3-phosphate, phosphoserine and pyruvate. Our results demonstrate that the key components of a core metabolic pathway central to energy transduction and amino acid, sugar, nucleotide and lipid biosyntheses can be reconstituted in high yield under mild, prebiotically plausible conditions.

Prebiotic synthesis of imidazole-4-acetaldehyde and histidine

NASA Astrophysics Data System (ADS)

Shen, Chun; Yang, Lily; Miller, Stanley L.; Oró, J.

1987-09-01

The prebiotic synthesis of imidazole-4-acetaldehyde and imidazole-4-glycol from erythrose and formamidine has been demonstrated as well as the prebiotic synthesis of imidazole-4-ethanol and imidazole-4-glycol from erythrose, formaldehyde and ammonia. The products were identified by TLC, HPLC, and LC-MS by comparison with authentic samples. The maximum yields of imidazole-4-acetaldehyde, imidazole-4-ethanol, and imidazole-4-glycol obtained in these reactions are 1.6, 5.4, 6.8% respectively, based on the erythrose. Imidazole-4-acetaldehyde would have been converted to histidine on the primitive earth by a Strecker synthesis, and several prebiotic reactions would convert imidazole-4-glycol and imidazole-4-ethanol to imidazole-4-acetaldehyde.

Atmospheric Prebiotic Chemistry and Organic Hazes

NASA Technical Reports Server (NTRS)

Trainer, Melissa G.

2012-01-01

Earth's atmospheric composition at the time of the origin of life is not known, but it has often been suggested that chemical transformation of reactive species in the atmosphere was a significant source of pre biotic organic molecules. Experimental and theoretical studies over the past half century have shown that atmospheric synthesis can yield molecules such as amino acids and nucleobases, but these processes are very sensitive to gas composition and energy source. Abiotic synthesis of organic molecules is more productive in reduced atmospheres, yet the primitive Earth may not have been as reducing as earlier workers assumed, and recent research has reflected this shift in thinking. This work provides a survey of the range of chemical products that can be produced given a set of atmospheric conditions, with a particular focus on recent reports. Intertwined with the discussion of atmospheric synthesis is the consideration of an organic haze layer, which has been suggested as a possible ultraviolet shield on the anoxic early Earth. Since such a haze layer - if formed - would serve as a reservoir for organic molecules, the chemical composition of the aerosol should be closely examined. The results highlighted here show that a variety of products can be formed in mildly reducing or even neutral atmospheres, demonstrating that contributions of atmospheric synthesis to the organic inventory on early Earth should not be discounted. This review intends to bridge current knowledge of the range of possible atmospheric conditions in the prebiotic environment and pathways for synthesis under such conditions by examining the possible products of organic chemistry in the early atmosphere.

Prebiotic Synthesis of Diaminopyrimidine and Thiocytosine

NASA Technical Reports Server (NTRS)

Robertson, Michael P.; Levy, Matthew; Miller, Stanley L.

1996-01-01

The reaction of guanidine hydrochloride with cyanoacetaldehyde gives high yields (40-85%) of 2,4-diaminopyrimidine under the concentrated conditions of a drying lagoon model of prebiotic synthesis, in contrast to the low yields previously obtained under more dilute conditions. The prebiotic source of cyanoacetaldehyde, cyanoacetylene, is produced from electric discharges under reducing conditions. The effect of pH and concentration of guanidine hydrochloride on the rate of synthesis and yield of diaminopyrimidine were investigated, as well as the hydrolysis of diaminopyrimidine to cytosine, isocytosine, and uracil. Thiourea also reacts with cyanoacetaldehyde to give 2-thiocytosine, but the pyrimidine yields are much lower than with guanidine hydrochloride or urea. Thiocytosine hydrolyzes to thiouracil and cytosine and then to uracil. This synthesis would have been a significant prebiotic source of 2-thiopyrimidines and 5-substituted derivatives of thiouracil, many of which occur in tRNA. The applicability of these results to the drying lagoon model of prebiotic synthesis was tested by dry-down experiments where dilute solutions of cyanoacetaldehyde, guanidine hydrochloride, and 0.5 M NaCl were evaporated over varying periods of time. The yields of diaminopyrimidine varied from 1 to 7%. These results show that drying lagoons and beaches may have been major sites of prebiotic syntheses.

Prebiotic chemistry in eutectic solutions at the water-ice matrix.

PubMed

Menor-Salván, César; Marín-Yaseli, Margarita R

2012-08-21

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 significantly high rates from a prebiotic chemistry standpoint, and the labile products can be protected from degradation. The experimental study of the synthesis of nitrogen heterocycles at the ice-water system showed the efficiency of this scenario and could explain the origin of nucleobases in the inner Solar System bodies, including meteorites and extra-terrestrial ices, and on the early Earth. The same conditions can also favour the condensation of monomers to form ribonucleic acid and peptides. Together with the synthesis of these monomers, the ice world (i.e., the chemical evolution in the range between the freezing point of water and the limit of stability of liquid brines, 273 to 210 K) is an under-explored experimental model in prebiotic chemistry.

UV-light-driven prebiotic synthesis of iron-sulfur clusters

NASA Astrophysics Data System (ADS)

Bonfio, Claudia; Valer, Luca; Scintilla, Simone; Shah, Sachin; Evans, David J.; Jin, Lin; Szostak, Jack W.; Sasselov, Dimitar D.; Sutherland, John D.; Mansy, Sheref S.

2017-12-01

Iron-sulfur clusters are ancient cofactors that play a fundamental role in metabolism and may have impacted the prebiotic chemistry that led to life. However, it is unclear whether iron-sulfur clusters could have been synthesized on prebiotic Earth. Dissolved iron on early Earth was predominantly in the reduced ferrous state, but ferrous ions alone cannot form polynuclear iron-sulfur clusters. Similarly, free sulfide may not have been readily available. Here we show that UV light drives the synthesis of [2Fe-2S] and [4Fe-4S] clusters through the photooxidation of ferrous ions and the photolysis of organic thiols. Iron-sulfur clusters coordinate to and are stabilized by a wide range of cysteine-containing peptides and the assembly of iron-sulfur cluster-peptide complexes can take place within model protocells in a process that parallels extant pathways. Our experiments suggest that iron-sulfur clusters may have formed easily on early Earth, facilitating the emergence of an iron-sulfur-cluster-dependent metabolism.

Quantum chemical study of relative reactivities of a series of amines and nitriles - Relevance to prebiotic chemistry

NASA Technical Reports Server (NTRS)

Loew, G. H.; Berkowitz, D.; Chang, S.

1975-01-01

Using the Iterative Extended Huckel Theory (IEHT) calculations of the electron distribution and orbital energies of a series of thirteen amines, nitriles and amino-nitriles relevant to prebiotic and cosmo-chemistry have been carried out. Ground state properties such as the energy and nature of the highest occupied (HOMO) and lowest empty (LEMO) molecular orbitals, net atomic charges and number of nonbonding electrons have been identified as criteria for correlating the relative nucleophilicity of amine and nitrile nitrogens and the electrophilicity of nitrile and other unsaturated carbon atoms. The results of such correlations can be partially verified by known chemical behavior of these compounds and are used to predict and understand their role in prebiotic organic synthesis.

The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems.

PubMed

Hill, Hugh G M; Nuth, Joseph A

2003-01-01

The synthesis of important prebiotic molecules is fundamentally reliant on basic starting ingredients: water, organic species [e.g., methane (CH(4))], and reduced nitrogen compounds [e.g., ammonia (NH(3)), methyl cyanide (CH(3)CN) etc.]. However, modern studies conclude that the primordial Earth's atmosphere was too rich in CO, CO(2), and water to permit efficient synthesis of such reduced molecules as envisioned by the classic Miller-Urey experiment. Other proposed sources of terrestrial nitrogen reduction, like those within submarine vent systems, also seem to be inadequate sources of chemically reduced C-H-O-N compounds. Here, we demonstrate that nebular dust analogs have impressive catalytic properties for synthesizing prebiotic molecules. Using a catalyst analogous to nebular iron silicate condensate, at temperatures ranging from 500K to 900K, we catalyzed both the Fischer-Tropsch conversion of CO and H(2) to methane and water, and the corresponding Haber-Bosch synthesis of ammonia from N(2) and H(2). Remarkably, when CO, N(2), and H(2) were allowed to react simultaneously, these syntheses also yielded nitrogen-containing organics such as methyl amine (CH(3)NH(2)), acetonitrile (CH(3)CN), and N-methyl methylene imine (H(3)CNCH(2)). A fundamental consequence of this work for astrobiology is the potential for a natural chemical pathway to produce complex chemical building blocks of life throughout our own Solar System and beyond.

The 1953 Stanley L. Miller Experiment: Fifty Years of Prebiotic Organic Chemistry

NASA Technical Reports Server (NTRS)

Lazcano, Antonio; Bada, Jeffrey L.

2003-01-01

The field of prebiotic chemistry effectively began with a publication in Science 50 years ago by Stanley L. Miller on the spark discharge synthesis of amino acids and other compounds using a mixture of reduced gases that were thought to represent the components of the atmosphere on the primitive Earth. On the anniversary of this landmark publication, we provide here an accounting of the events leading to the publication of the paper. We also discuss the historical aspects that lead up to the landmark Miller experiment.

The atmosphere of the primitive earth and the prebiotic synthesis of organic compounds

NASA Technical Reports Server (NTRS)

Miller, S. L.; Schlesinger, G.

1983-01-01

The prebiotic synthesis of organic compounds is investigated using a spark discharge on various simulated prebiotic atmospheres at 25 C. It is found that glycine is almost the only amino acid produced from the model atmospheres containing CO and CO2. These results show that the maximum yield is about the same for the three carbon sources (CO, CO2, and CH4) at high H2/carbon ratios, but that CH4 is superior at low H2/carbon ratios. CH4 is found to yield a much greater variety of amino acids than either CO or CO2. If it is assumed that amino acids more complex than glycine were required for the origin of life, then these findings indicate the need for CH4 in the primitive atmosphere. The yields of cyanide and formaldehyde are shown to parallel the amino acid results, with yields of HCN and H2CO as high as 13 percent based on carbon. Ammonia is also found to be produced from N2 in experiments with no added NH3 in yields as high as 4.9 percent. These results indicate that large amounts of NH3 would have been synthesized on the primitive earth by electric discharges.

Influence of the UV Environment on the Synthesis of Prebiotic Molecules.

PubMed

Ranjan, Sukrit; Sasselov, Dimitar D

2016-01-01

Ultraviolet radiation is common to most planetary environments and could play a key role in the chemistry of molecules relevant to abiogenesis (prebiotic chemistry). In this work, we explore the impact of UV light on prebiotic chemistry that might occur in liquid water on the surface of a planet with an atmosphere. We consider effects including atmospheric absorption, attenuation by water, and stellar variability to constrain the UV input as a function of wavelength. We conclude that the UV environment would be characterized by broadband input, and wavelengths below 204 nm and 168 nm would be shielded out by atmospheric CO2 and water, respectively. We compare this broadband prebiotic UV input to the narrowband UV sources (e.g., mercury lamps) often used in laboratory studies of prebiotic chemistry and explore the implications for the conclusions drawn from these experiments. We consider as case studies the ribonucleotide synthesis pathway of Powner et al. (2009) and the sugar synthesis pathway of Ritson and Sutherland (2012). Irradiation by narrowband UV light from a mercury lamp formed an integral component of these studies; we quantitatively explore the impact of more realistic UV input on the conclusions that can be drawn from these experiments. Finally, we explore the constraints solar UV input places on the buildup of prebiotically important feedstock gasses like CH4 and HCN. Our results demonstrate the importance of characterizing the wavelength dependence (action spectra) of prebiotic synthesis pathways to determine how pathways derived under laboratory irradiation conditions will function under planetary prebiotic conditions.

Simultaneous existence of different enviroments in aqueous clay systems and its possible role in prebiotic synthesis.

PubMed

Lahav, N

1975-08-05

The formation of packets of parallel oriented platelets and separating distances of several angstrom units in montmorillonite-water systems produces an intrinsic inhomogeneity with respect to the proton donating power of internal and external zones. Stable packets can be induced by both inorganic and organic molecules or ions, in suspensions or in drying-out systems. The coexistence of zones with different proton donating power was demonstrated by the pH-sensitive color reaction of benzidine, where stable packets of montmorillonite platelets were formed by the use of either paraquat or diquat. The close proximity of the two types of zones, which can be of the order of several angstroms, produces the conditions which were defined by Katchalsky as essential for the polymerization of amino acids. Since these enviromental conditions are quite common in nature, both at present and in prebiotic times, it is proposed that the inhomogeneity of clay-water systems with respect to proton donating power should be taken into account in both theoretical and experimental efforts to demonstrate the catalytic activity of clays in prebiotic synthesis.

Synthesis of novel bioactive lactose-derived oligosaccharides by microbial glycoside hydrolases

PubMed Central

Díez-Municio, Marina; Herrero, Miguel; Olano, Agustín; Moreno, F Javier

2014-01-01

Prebiotic oligosaccharides are increasingly demanded within the Food Science domain because of the interesting healthy properties that these compounds may induce to the organism, thanks to their beneficial intestinal microbiota growth promotion ability. In this regard, the development of new efficient, convenient and affordable methods to obtain this class of compounds might expand even further their use as functional ingredients. This review presents an overview on the most recent interesting approaches to synthesize lactose-derived oligosaccharides with potential prebiotic activity paying special focus on the microbial glycoside hydrolases that can be effectively employed to obtain these prebiotic compounds. The most notable advantages of using lactose-derived carbohydrates such as lactosucrose, galactooligosaccharides from lactulose, lactulosucrose and 2-α-glucosyl-lactose are also described and commented. PMID:24690139

Prebiotic synthesis of histidine

NASA Technical Reports Server (NTRS)

Shen, C.; Yang, L.; Miller, S. L.; Oro, J.

1990-01-01

The prebiotic formation of histidine (His) has been accomplished experimentally by the reaction of erythrose with formamidine followed by a Strecker synthesis. In the first step of this reaction sequence, the formation of imidazole-4-acetaldehyde took place by the condensation of erythrose and formamidine, two compounds that are known to be formed under prebiotic conditions. In a second step, the imidazole-4-acetaldehyde was converted to His, without isolation of the reaction products by adding HCN and ammonia to the reaction mixture. LC, HPLC, thermospray liquid chromatography-mass spectrometry, and tandem mass spectrometry were used to identify the product, which was obtained in a yield of 3.5% based on the ratio of His/erythrose. This is a new chemical synthesis of one of the basic amino acids which had not been synthesized prebiotically until now.

Prebiotic Synthesis of Methionine and Other Sulfur-Containing Organic Compounds on the Primitive Earth: A Contemporary Reassessment Based on an Unpublished 1958 Stanley Miller Experiment

NASA Technical Reports Server (NTRS)

Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; Lazcano, Antonio

2010-01-01

Original extracts from an unpublished 1958 experiment conducted by the late Stanley L. Miller were recently found and analyzed using modern state-of-the-art analytical methods. The extracts were produced by the action of an electric discharge on a mixture of methane (CH4), hydrogen sulfide (H2S), ammonia (NH3), and carbon dioxide (CO2). Racemic methionine was farmed in significant yields, together with other sulfur-bearing organic compounds. The formation of methionine and other compounds from a model prebiotic atmosphere that contained H2S suggests that this type of synthesis is robust under reducing conditions, which may have existed either in the global primitive atmosphere or in localized volcanic environments on the early Earth. The presence of a wide array of sulfur-containing organic compounds produced by the decomposition of methionine and cysteine indicates that in addition to abiotic synthetic processes, degradation of organic compounds on the primordial Earth could have been important in diversifying the inventory of molecules of biochemical significance not readily formed from other abiotic reactions, or derived from extraterrestrial delivery.

Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules - An inventory for the origins of life

NASA Technical Reports Server (NTRS)

Chyba, Christopher; Sagan, Carl

1992-01-01

The contribution of organic-rich comets, carbonaceous asteroids, and interplanetary dust particles and of impact shock-synthesized organics in the atmosphere to the origin of life on earth is studied and quantitatively compared with the principal non-heavy-bombardment sources of prebiotic organics. The results suggest that heavy bombardment before 3.5 Gyr ago either produced or delivered quantities of organics comparable to those produced by other energy sources.

Synthesis of Organic Matter of Prebiotic Chemistry at the Protoplanetary Disc

NASA Astrophysics Data System (ADS)

Snytnikov, Valeriy; Stoynovskaya, Olga; Rudina, Nina

We have carried out scanning electron microscopic examination of CM carbonaceous chondrites meteorites Migey, Murchison, Staroe Boriskino aged more than 4.56 billion years (about 50 million years from the beginning of the formation of the Solar system). Our study confirmed the conclusion of Rozanov, Hoover and other researchers about the presence of microfossils of bacterial origin in the matrix of all these meteorites. Since the time of the Solar system formation is 60 - 100 million years, the primary biocenosis emerged in the protoplanetary disc of the Solar system before meteorites or simultaneously with them. It means that prebiological processes and RNA world appeared even earlier in the circumsolar protoplanetary disc. Most likely, this appearance of prebiotic chemistry takes place nowday in massive and medium-massive discs of the observed young stellar objects (YSO) class 0 and I. The timescale of the transition from chemical to biological evolution took less than 50 million years for the Solar system. Further evolution of individual biocenosis in a protoplanetary disc associated with varying physico-chemical conditions during the formation of the Solar system bodies. Biocenosis on these bodies could remove or develop under the influence of many cosmic factors and geological processes in the case of Earth. To complete the primary biosphere formation in short evolution time - millions of years - requires highly efficient chemical syntheses. In industrial chemistry for the efficient synthesis of ammonia, hydrogen cyanide, methanol and other organic species, that are the precursors to obtain prebiotic compounds, catalytic reactors of high pressure are used. Thus (1) necessary amount of the proper catalyst in (2) high pressure areas of the disc can trigger these intense syntheses. The disc contains the solids with the size from nanoparticle to pebble. Iron and magnesium is catalytically active ingredient for such solids. The puzzle is a way to provide hydrogen pressure inside the disc from tens to hundred atmospheres. We simulated unsteady processes in massive circumstellar discs around YSO class O and I. In the computational experiments, we have shown that at a certain stage of its evolution the circumstellar discs of gas and solids produces local areas of high pressure. According to the classical heterogeneous catalysis, a wide range of organic and prebiotic compounds could have been synthesized in these areas. Can we capture these areas of high pressure synthesis in observation of circumstellar discs? Due to the small sizes of such areas they can be hardly ever resolved even with the modern telescopes such as ALMA. However, we can try to detect their signatures in the disc, since the gas of the disc keep the set of organic synthesis products. The idea is to define the signature of the process using laboratory experiments. Varying gas temperature and pressure in laboratory setup we can carry out the catalytic high pressure syntheses and specify the set of gaseous products. These sets of organic compounds observed in the discs may serve as indicators of the emergence of high-pressure areas of prebiotic chemistry. Thus, there is a special interest to the study of YSO class 0 and I by means of observational astronomy. For these objects, first data on the presence of individual organic compounds in massive hydrogen-helium component of the discs appear. The origin of the organic compounds that are associated with chemical reactions in the discs should be separated from the set of organic compounds of the initial molecular cloud.

Catalysis and prebiotic RNA synthesis

NASA Technical Reports Server (NTRS)

Ferris, James P.

1993-01-01

The essential role of catalysis for the origins of life is discussed. The status of the prebiotic synthesis of 2',5'- and 3'5'-linked oligomers of RNA is reviewed. Examples of the role of metal ion and mineral catalysis in RNA oligomer formation are discussed.

Geochemical Origin of Biological Molecules

NASA Astrophysics Data System (ADS)

Bassez, Marie-Paule

2013-04-01

A model for the geochemical origin of biological molecules is presented. Rocks such as peridotites and basalts, which contain ferromagnesian minerals, evolve in the presence of water. Their hydrolysis is an exothermic reaction which generates heat and a release of H2 and of minerals with modified structures. The hydrogen reacts with the CO2 embedded inside the rock or with the CO2 of the environment to form CO in an hydrothermal process. With the N2 of the environment, and with an activation source arising from cosmic radiation, ferromagnesian rocks might evolve towards the abiotic formation of biological molecules, such as peptide like macromolecules which produce amino acids after acid hydrolysis. The reactions concerned are described. The production of hydrothermal CO is discussed in geological sites containing ferromagnesian silicate minerals and the low intensity of the Earth's magnetic field during Paleoarchaean Era is also discussed. It is concluded that excitation sources arising from cosmic radiation were much more abundant during Paleoarchaean Era and that macromolecular structures of biological relevance might consequently form during Archaean Eon, as a product of the chemical evolution of the rocks and of their mineral contents. This synthesis of abiotically formed biological molecules is consecutively discussed for meteorites and other planets such as Mars. This model for the geochemical origin of biological molecules has first been proposed in 2008 in the context of reactions involving catalysers such as kaolinite [Bassez 2008a] and then presented in conferences and articles [Bassez 2008b, 2009, 2012; Bassez et al. 2009a to 2012b]. BASSEZ M.P. 2008a Synthèse prébiotique dans les conditions hydrothermales, CNRIUT'08, Lyon 29-30/05/2008, Conf. and open access article:http://liris.cnrs.fr/~cnriut08/actes/ 29 mai 11h-12h40. BASSEZ M.P. 2008b Prebiotic synthesis under hydrothermal conditions, ISSOL'08, P2-6, Firenze-Italy, 24-29/08/2008. Poster at the Conference and abstract in OLEB, 2008, 39 (3-4) 223. BASSEZ M.P. 2009 Prebiotic synthesis under hydothermal conditions, C. R. Chimie, Académie des Sciences, Paris 12 (6-7) : 801-807. BASSEZ M.P. 2012 A model for a geochemical origin of life in preparation BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2009a Organic analysis of peridotite rocks from Ashadze and Logatchev hydrothermal sites, Int. J. Mol. Sci. 10(7): 2986-2998. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2009b Organic analysis of peridotite rocks from the MAR, AGU fall meeting, P43C-1441, San Francisco, 14-18/12/2009. BASSEZ M.P., TAKANO Y. 2010a Prebiotic organic globules, Nature Precedings: Posted 21 Jul http://hdl:10101/npre.2010.4694.1. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2010b Organic analysis of peridotite rocks, First chemical steps towards the Origin of Life colloquium, Turin 16-17/09/2010. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2011a A search for prebiotic molecular signatures inside rocks, Geobiology in Space exploration workshop, P sans n°, Marrakech 07-14/02/2011. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2011b Detection of molecular biosignatures inside rocks, Origins 2011 ISSOL and Bioastronomy conference, P2-17, Montpellier, 04-08/07/2011. BASSEZ M.P., TAKANO Y., 2011c Organic microstructures, Origins 2011 ISSOL and Bioastronomy conference, P2-34, Montpellier, 04-08/07/2011. BASSEZ M.P., TAKANO Y. KOBAYASHI K. 2011d Prebiotic organic microstructures, Nature Precedings: Posted 14 Nov. http://hdl.handle.net/10101/npre.2011.4694.2 BASSEZ M.P., TAKANO Y., KOBAYASHI K. 2012a Prebiotic organic microstructures, Origin of Life Gordon Research Conference P4, Galveston, 08-13/01/2012. BASSEZ M.P., TAKANO Y., KOBAYASHI K. 2012b Prebiotic organic microstructures, Orig. Life Evol. Biosph. 42 (4) : 307-316.

Abiotic Organic Chemistry in Hydrothermal Systems.

NASA Astrophysics Data System (ADS)

Simoneit, B. R.; Rushdi, A. I.

2004-12-01

Abiotic organic chemistry in hydrothermal systems is of interest to biologists, geochemists and oceanographers. This chemistry consists of thermal alteration of organic matter and minor prebiotic synthesis of organic compounds. Thermal alteration has been extensively documented to yield petroleum and heavy bitumen products from contemporary organic detritus. Carbon dioxide, carbon monoxide, ammonia and sulfur species have been used as precursors in prebiotic synthesis experiments to organic compounds. These inorganic species are common components of hot spring gases and marine hydrothermal systems. It is of interest to further test their reactivities in reductive aqueous thermolysis. We have synthesized organic compounds (lipids) in aqueous solutions of oxalic acid, and with carbon disulfide or ammonium bicarbonate at temperatures from 175-400° C. The synthetic lipids from oxalic acid solutions consisted of n-alkanols, n-alkanoic acids, n-alkyl formates, n-alkanones, n-alkenes and n-alkanes, typically to C30 with no carbon number preferences. The products from CS2 in acidic aqueous solutions yielded cyclic thioalkanes, alkyl polysulfides, and thioesters with other numerous minor compounds. The synthesis products from oxalic acid and ammonium bicarbonate solutions were homologous series of n-alkyl amides, n-alkyl amines, n-alkanes and n-alkanoic acids, also to C30 with no carbon number predominance. Condensation (dehydration) reactions also occur under elevated temperatures in aqueous medium as tested by model reactions to form amide, ester and nitrile bonds. It is concluded that the abiotic formation of aliphatic lipids, condensation products (amides, esters, nitriles, and CS2 derivatives (alkyl polysulfides, cyclic polysulfides) is possible under hydrothermal conditions and warrants further studies.

Divergent prebiotic synthesis of pyrimidine and 8-oxo-purine ribonucleotides

NASA Astrophysics Data System (ADS)

Stairs, Shaun; Nikmal, Arif; Bučar, Dejan-Krešimir; Zheng, Shao-Liang; Szostak, Jack W.; Powner, Matthew W.

2017-05-01

Understanding prebiotic nucleotide synthesis is a long standing challenge thought to be essential to elucidating the origins of life on Earth. Recently, remarkable progress has been made, but to date all proposed syntheses account separately for the pyrimidine and purine ribonucleotides; no divergent synthesis from common precursors has been proposed. Moreover, the prebiotic syntheses of pyrimidine and purine nucleotides that have been demonstrated operate under mutually incompatible conditions. Here, we tackle this mutual incompatibility by recognizing that the 8-oxo-purines share an underlying generational parity with the pyrimidine nucleotides. We present a divergent synthesis of pyrimidine and 8-oxo-purine nucleotides starting from a common prebiotic precursor that yields the β-ribo-stereochemistry found in the sugar phosphate backbone of biological nucleic acids. The generational relationship between pyrimidine and 8-oxo-purine nucleotides suggests that 8-oxo-purine ribonucleotides may have played a key role in primordial nucleic acids prior to the emergence of the canonical nucleotides of biology.

Application of the Organic Synthetic Designs to Astrobiology

NASA Astrophysics Data System (ADS)

Kolb, V. M.

2009-12-01

In this paper we propose a synthesis of the heterocyclic compounds and the insoluble materials on the meteorites. Our synthetic scheme involves the reaction of sugars and amino acids, the so-called Maillard reaction. We have developed this scheme based on the combined analysis of the regular and retrosynthetic organic synthetic principles. The merits of these synthetic methods for the prebiotic design are addressed.

From the Primitive Atmosphere to the Prebiotic Soup to the Pre-RNA World

NASA Technical Reports Server (NTRS)

Miller, Stanley L.

1996-01-01

Organic compounds would have been produced in an earth's atmosphere that was reducing. The soup would contain amino and hydroxy acids, together with smaller amounts of purines and pyrimidines. The presence' of sugars is less likely, although they can be produced by the formose reaction from formaldehyde. However, the prebiotic synthesis of RNA has not been demonstrated. One problem is that ribose is not produced selectively over other pentoses and hexoses, except under special conditions. The second problem is that ribose is unstable, with a half-life at pH7 and 100 C of 73 minutes (44 years at 0 C). Other sugars are similarly unstable. Another problem is that there is no efficient prebiotic synthesis of polyphosphates, nor the glycosidic bond of nucleosides. This suggests that there may have been an informational macromolecule that preceded RNA. The RNA world refers to the time when RNA carried both the genetic information and the catalytic activity, and was subsequently converted to the DNA/protein world when protein synthesis began. Preceeding the RNA world was the Pre-RNA world, where a backbone different from ribose phosphate was used, and the bases may have been different from adenine, uracil, guanine and cytosine. We have shown recently that cytosine and uracil can be synthesized efficiently under prebiotic conditions using a dried lagoon model instead of the usual dilute ocean hypothesis. In addition, we have shown that uracil adds formaldehyde efficiently to give 5- hydroxymethyl uracil, which in turn adds various nucleophiles to give uracil analogs of most of the amino acids that occur in proteins. For example, the ammonia, guanidine and imidazole adducts from the analogs of lysine, arginine and histidine. This suggests that the catalytic potential of RNA may have been much more extensive than previously assumed. The major problem is finding out what was the precursor to the ribose phosphate backbone. This will be the key to developing prebiotic self-replicating systems.

Initialization of metabolism in prebiotic petroleum

NASA Astrophysics Data System (ADS)

Mekki-Berrada, Ali

The theoretical and bibliographical work on the geochemical origin of life, which I present here, it works on the assumption that: "The class of more complex molecules of life that can have a geochemical and abiotic origin is the class of fatty acid with long aliphatic chain". This idea comes from the controversy over the abiotic oil industry, and the first measurements of abiotic oil at mid-ocean ridges (Charlou J.L. et al. 2002, Proskurowski G. et al. 2008). To go further and propose a comprehensive experimentation on the origin of life, I propose in this article the idea that the prebiotic soup or prebiotic petroleum would stem from the diagenesis of the gas clathrates/sediments mixture. Gas, H2S H2 N2 CH4 CO2, are produced at mid-ocean ridges, and at large-scale at the seafloor, by serpentinization. Sediments contain hydrogenophosphates as a source of phosphate and minerals to the surface catalysis. Extreme conditions experienced by some prokaryotes and pressures and temperatures of submarine oilfields of fossil petroleum are close. The hydrostatic pressure is around 1.5 kbar and the temperature is below 150 °C. This experiment I propose is quite feasible today since these conditions are used: In research and exploration of fossil petroleum; In the field of organic chemistry called "green chemistry" and where temperatures remain low and the pressure can reach 10 kbar; to study the biology of prokaryotes living in the fossil petroleum of industrial interest, these studies are quite comparable to experiment with prebiotic oil; Finally, this experiment can be based on research on abiotic CH4 on Mars and abiotic hydrocarbons on Titan. The next step in the theoretical research of the origin of life is the abiotic synthesis of liposomes. Abiotic synthesis liposomes just requires synthesis of glycerol and ethanolamine (or serine) esterifying the phosphate and fatty acid. The state of research on the abiotic synthesis of these molecules shows that synthesis of glycerol in the laboratory and in industry are so drastic and complex that I proposed initialization metabolism in fatty acid vesicles with hydrogenation by H2 of glyceraldehyde-P or dihydroxyacetone-P to glycerol-3P after esterification to the fatty acid. Hydrogenation is assumed to be facilitated by the catalyst power of the multi-anionic surface of these vesicles. https://en.wikiversity.org/wiki/Prebiotic_Petroleum

Prebiotic syntheses of vitamin coenzymes: I. Cysteamine and 2-mercaptoethanesulfonic acid (coenzyme M)

NASA Technical Reports Server (NTRS)

Miller, S. L.; Schlesinger, G.

1993-01-01

The reaction of NH3 and SO3(2-) with ethylene sulfide is shown to be a prebiotic synthesis of cysteamine and 2-mercaptoethanesulfonic acid (coenzyme M). A similar reaction with ethylene imine would give cysteamine and taurine. Ethylene oxide would react with NH3 and N(CH3)3 to give the phospholipid components ethanolamine and choline. The prebiotic sources of ethylene sulfide, ethylene imine and ethylene oxide are discussed. Cysteamine itself is not a suitable thioester for metabolic processes because of acyl transfer to the amino group, but this can be prevented by using an amide of cysteamine. The use of cysteamine in coenzyme A may have been due to its prebiotic abundance. The facile prebiotic synthesis of both cysteamine and coenzyme M suggests that they were involved in very early metabolic pathways.

Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation

PubMed Central

Saladino, Raffaele; Carota, Eleonora; Botta, Giorgia; Kapralov, Mikhail; Timoshenko, Gennady N.; Rozanov, Alexei Y.; Krasavin, Eugene; Di Mauro, Ernesto

2015-01-01

Liquid formamide has been irradiated by high-energy proton beams in the presence of powdered meteorites, and the products of the catalyzed resulting syntheses were analyzed by mass spectrometry. Relative to the controls (no radiation, or no formamide, or no catalyst), an extremely rich, variegate, and prebiotically relevant panel of compounds was observed. The meteorites tested were representative of the four major classes: iron, stony iron, chondrites, and achondrites. The products obtained were amino acids, carboxylic acids, nucleobases, sugars, and, most notably, four nucleosides: cytidine, uridine, adenosine, and thymidine. In accordance with theoretical studies, the detection of HCN oligomers suggests the occurrence of mechanisms based on the generation of radical cyanide species (CN·) for the synthesis of nucleobases. Given that many of the compounds obtained are key components of extant organisms, these observations contribute to outline plausible exogenous high-energy–based prebiotic scenarios and their possible boundary conditions, as discussed. PMID:25870268

Mimicking the surface and prebiotic chemistry of early Earth using flow chemistry.

PubMed

Ritson, Dougal J; Battilocchio, Claudio; Ley, Steven V; Sutherland, John D

2018-05-08

When considering life's aetiology, the first questions that must be addressed are "how?" and "where?" were ostensibly complex molecules, considered necessary for life's beginning, constructed from simpler, more abundant feedstock molecules on primitive Earth. Previously, we have used multiple clues from the prebiotic synthetic requirements of (proto)biomolecules to pinpoint a set of closely related geochemical scenarios that are suggestive of flow and semi-batch chemistries. We now wish to report a multistep, uninterrupted synthesis of a key heterocycle (2-aminooxazole) en route to activated nucleotides starting from highly plausible, prebiotic feedstock molecules under conditions which mimic this scenario. Further consideration of the scenario has uncovered additional pertinent and novel aspects of prebiotic chemistry, which greatly enhance the efficiency and plausibility of the synthesis.

The prebiotic synthesis of oligonucleotides

NASA Technical Reports Server (NTRS)

Oro, J.; Stephen-Sherwood, E.

1974-01-01

This paper is primarily a review of recent developments in the abiotic synthesis of nucleotides, short chain oligonucleotides, and their mode of replication in solution. It also presents preliminary results from this laboratory on the prebiotic synthesis of thymidine oligodeoxynucleotides. A discussion, based on the physicochemical properties of RNA and DNA oligomers, relevant to the molecular evolution of these compounds leads to the tentative hypothesis that oligodeoxyribonucleotides of about 12 units may have been of sufficient length to initiate a self replicating coding system. Two models are suggested to account for the synthesis of high molecular weight oligomers using short chain templates and primers.

Oxidative acylation using thioacids

NASA Technical Reports Server (NTRS)

Liu, R.; Orgel, L. E.

1997-01-01

Several important prebiotic reactions, including the coupling of amino acids into polypeptides by the formation of amide linkages, involve acylation. Theae reactions present a challenge to the understanding of prebiotic synthesis. Condensation reactions relying on dehydrating agents are either inefficient in aqueous solution or require strongly acidic conditions and high temperatures. Activated amino acids such as thioester derivatives have therefore been suggested as likely substrates for prebiotic peptide synthesis. Here we propose a closely related route to amide bond formation involving oxidative acylation by thioacids. We find that phenylalanine, leucine and phenylphosphate are acylated efficiently in aqueous solution by thioacetic acid and an oxidizing agent. From a prebiotic point of view, oxidative acylation has the advantage of proceeding efficiently in solution and under mild conditions. We anticipate that oxidative acylation should prove to be a general method for activating carboxylic acids, including amino acids.

Synthesis of β-Peptide Standards for Use in Model Prebiotic Reactions

NASA Astrophysics Data System (ADS)

Forsythe, Jay G.; English, Sloane L.; Simoneaux, Rachel E.; Weber, Arthur L.

2018-05-01

A one-pot method was developed for the preparation of a series of β-alanine standards of moderate size (2 to ≥12 residues) for studies concerning the prebiotic origins of peptides. The one-pot synthesis involved two sequential reactions: (1) dry-down self-condensation of β-alanine methyl ester, yielding β-alanine peptide methyl ester oligomers, and (2) subsequent hydrolysis of β-alanine peptide methyl ester oligomers, producing a series of β-alanine peptide standards. These standards were then spiked into a model prebiotic product mixture to confirm by HPLC the formation of β-alanine peptides under plausible reaction conditions. The simplicity of this approach suggests it can be used to prepare a variety of β-peptide standards for investigating differences between α- and β-peptides in the context of prebiotic chemistry.

Studies of Life on Earth are Important for Mars Exploration

NASA Technical Reports Server (NTRS)

DesMarais, D. J.

1998-01-01

The search for evidence of the early martian environment and a martian biosphere is benefitted by diverse studies of life on Earth. Most fundamentally, origin-of-life research highlights the challenge in formulating a rigorous definition of life. Because such definitions typically list several of life's most basic properties, they also help to define those observable features that distinguish life and thus might be sought through telescopes, spacecraft, and analyses of extraterrestrial samples. Studies of prebiotic chemistry also help by defining the range of environments and processes that sustain prebiotic organic synthesis. These studies might indicate if and where prebiotic processes occur today on Earth and elsewhere. Such studies should also help to identify which localities are good candidates for the origin of life. A better understanding of the most fundamental principles by which molecules are assembled into living systems will help us to appreciate possible alternatives to the path followed by life on Earth. These perspectives will sharpen our ability to recognize exotic life and/or those environments that can sustain it.

The composition of the primitive atmosphere and the synthesis of organic compounds on the early Earth

NASA Technical Reports Server (NTRS)

Bada, J. L.; Miller, S. L.

1985-01-01

The generally accepted theory for the origin of life on the Earth requires that a large variety of organic compounds be present to form the first living organisms and to provide the energy sources for primitive life either directly or through various fermentation reactions. This can provide a strong constraint on discussions of the formation of the Earth and on the composition of the primitive atmosphere. In order for substantial amounts of organic compounds to have been present on the prebiological Earth, certain conditions must have existed. There is a large body of literature on the prebiotic synthesis of organic compounds in various postulated atmospheres. In this mixture of abiotically synthesized organic compounds, the amino acids are of special interest since they are utilized by modern organisms to synthesize structural materials and a large array of catalytic peptides.

Electron-induced origins of prebiotic building blocks of sugars: mechanism of self-reactions of a methanol anion dimer

NASA Astrophysics Data System (ADS)

Karsili, Tolga N. V.; Fennimore, Mark A.; Matsika, Spiridoula

The elementary synthesis of prebiotic molecules has attracted vast attention in recent years. Due to their rich surface chemistry and lack of suitable atmosphere, comets represent an important host for such synthesis, especially since they are routinely irradiated with short wavelength electromagnetic radiation and energetic cosmological electrons. Using high-level electronic structure theory, we present the details of the reactivity associated with the electron-impact induced prebiotic synthesis of ethylene glycol (a carbohydrate building block) from elementary methanol. The results suggest that the experimentally observed intermediates and fragment products can be viably formed by both neutral excited-state chemistry and by dissociative electron attachment - highlighting the importance of a theoretical mapping of the relevant potential energy surfaces that ultimately act as an important guide to the experimental results.

Life’s Order, Complexity, Organization, and Its Thermodynamic–Holistic Imperatives

PubMed Central

Egel, Richard

2012-01-01

In memoriam Jeffrey S. Wicken (1942–2002)—the evolutionarily minded biochemist, who in the 1970/80s strived for a synthesis of biological and physical theories to fathom the tentative origins of life. Several integrative concepts are worth remembering from Wicken’s legacy. (i) Connecting life’s origins and complex organization to a preexisting physical world demands a thermodynamically sound transition. (ii) Energetic ‘charging’ of the prebiosphere must precede the emergence of biological organization. (iii) Environmental energy gradients are exploited progressively, approaching maximum interactive structure and minimum dissipation. (iv) Dynamic self-assembly of prebiotic organic matter is driven by hydrophobic tension between water and amphiphilic building blocks, such as aggregating peptides from non-polar amino acids and base stacking in nucleic acids. (v) The dynamics of autocatalytic self-organization are facilitated by a multiplicity of weak interactions, such as hydrogen bonding, within and between macromolecular assemblies. (vi) The coevolution of (initially uncoded) proteins and nucleic acids in energy-coupled and metabolically active so-called ‘microspheres’ is more realistic as a kinetic transition model of primal biogenesis than ‘hypercycle replication’ theories for nucleic acid replicators on their own. All these considerations blend well with the current understanding that sunlight UV-induced photo-electronic excitation of colloidal metal sulfide particles appears most suitable as a prebiotic driver of organic synthesis reactions, in tight cooperation with organic, phase-separated, catalytic ‘microspheres’. On the ‘continuist vs. miraculist’ schism described by Iris Fry for origins-of-life considerations (Table 1), Wicken was a fervent early protagonist of holistic ‘continuist’ views and agenda. PMID:25371269

Prebiotic selection and assembly of proteinogenic amino acids and natural nucleotides from complex mixtures

NASA Astrophysics Data System (ADS)

Islam, Saidul; Bučar, Dejan-Krešimir; Powner, Matthew W.

2017-06-01

A central problem for the prebiotic synthesis of biological amino acids and nucleotides is to avoid the concomitant synthesis of undesired or irrelevant by-products. Additionally, multistep pathways require mechanisms that enable the sequential addition of reactants and purification of intermediates that are consistent with reasonable geochemical scenarios. Here, we show that 2-aminothiazole reacts selectively with two- and three-carbon sugars (glycolaldehyde and glyceraldehyde, respectively), which results in their accumulation and purification as stable crystalline aminals. This permits ribonucleotide synthesis, even from complex sugar mixtures. Remarkably, aminal formation also overcomes the thermodynamically favoured isomerization of glyceraldehyde into dihydroxyacetone because only the aminal of glyceraldehyde separates from the equilibrating mixture. Finally, we show that aminal formation provides a novel pathway to amino acids that avoids the synthesis of the non-proteinogenic α,α-disubstituted analogues. The common physicochemical mechanism that controls the proteinogenic amino acid and ribonucleotide assembly from prebiotic mixtures suggests that these essential classes of metabolite had a unified chemical origin.

The case for a Martian origin for Earth life

NASA Astrophysics Data System (ADS)

Benner, Steven A.; Kim, Hyo-Joong

2015-09-01

Classical prebiotic chemistry, which has for the last half century explored the reactivity of small organic molecules in glassware environments under the control of chemists, has left unanswered multiple paradoxes with respect to the origins of life. Many of these can be approached, and possibly solved, by placing organic molecular reactivity within the context of the rocks, minerals, hydrosphere, and atmosphere of a prebiotic earth. This new direction in prebiotic chemistry is discussed here, with special emphasis on the role of minerals in constraining the inherent propensity of carbohydrates to devolve to form unproductively complex mixtures of materials. We focus in particular on minerals containing the elements boron and molybdenum, which is produced in discontinuous synthesis model for the emergence of RNA as the first Darwinian molecule. Further, the role of desert environments to manage the "water paradox" is discussed in the context of many classes of processes that have been proposed to deliver RNA under prebiotic conditions. If current models are correct to suggest that early Earth may have been largely flooded at the time when life originated, Then those desert environments may not have been available. However, the inventory of water on Mars has always been less than on Earth and, as Kirschvink has pointed out, intercourse between the two planets was frequent during the time when life is emerging on either planets. This suggests that desert like environments may have been present on early Mars, if they were not present on early Earth.

Photoinduced catalytic synthesis of biologically important metabolites from formaldehyde and ammonia under plausible "prebiotic" conditions

NASA Astrophysics Data System (ADS)

Delidovich, I. V.; Taran, O. P.; Simonov, A. N.; Matvienko, L. G.; Parmon, V. N.

2011-08-01

The article analyzes new and previously reported data on several catalytic and photochemical processes yielding biologically important molecules. UV-irradiation of formaldehyde aqueous solution yields acetaldehyde, glyoxal, glycolaldehyde and glyceraldehyde, which can serve as precursors of more complex biochemically relevant compounds. Photolysis of aqueous solution of acetaldehyde and ammonium nitrate results in formation of alanine and pyruvic acid. Dehydration of glyceraldehyde catalyzed by zeolite HZSM-5-17 yields pyruvaldehyde. Monosaccharides are formed in the course of the phosphate-catalyzed aldol condensation reactions of glycolaldehyde, glyceraldehyde and formaldehyde. The possibility of the direct synthesis of tetroses, keto- and aldo-pentoses from pure formaldehyde due to the combination of the photochemical production of glycolahyde and phosphate-catalyzed carbohydrate chain growth is demonstrated. Erythrulose and 3-pentulose are the main products of such combined synthesis with selectivity up to 10%. Biologically relevant aldotetroses, aldo- and ketopentoses are more resistant to the photochemical destruction owing to the stabilization in hemiacetal cyclic forms. They are formed as products of isomerization of erythrulose and 3-pentulose. The conjugation of the concerned reactions results in a plausible route to the formation of sugars, amino and organic acids from formaldehyde and ammonia under presumed 'prebiotic' conditions.

Prebiotic Peptide (Amide) Bond Synthesis Accelerated by Glycerol and Bicarbonate Under Neutral to Alkaline Dry-Down Conditions

NASA Technical Reports Server (NTRS)

Forsythe, J. G.; Weber, A. L.

2017-01-01

Past studies of prebiotic peptide bond synthesis have generally been carried out in the acidic to neutral pH range [1, 2]. Here we report a new process for peptide bond (amide) synthesis in the neutral to alkaline pH range that involves simple dry-down heating of amino acids in the presence of glycerol and bicarbonate. Glycerol was included in the reaction mixture as a solvent and to provide hydroxyl groups for possible formation of ester intermediates previously implicated in peptide bond synthesis under acidic to neutral conditions [1]. Bicarbonate was added to raise the reaction pH to 8-9.

A new family of extraterrestrial amino acids in the Murchison meteorite.

PubMed

Koga, Toshiki; Naraoka, Hiroshi

2017-04-04

The occurrence of extraterrestrial organic compounds is a key for understanding prebiotic organic synthesis in the universe. In particular, amino acids have been studied in carbonaceous meteorites for almost 50 years. Here we report ten new amino acids identified in the Murchison meteorite, including a new family of nine hydroxy amino acids. The discovery of mostly C 3 and C 4 structural isomers of hydroxy amino acids provides insight into the mechanisms of extraterrestrial synthesis of organic compounds. A complementary experiment suggests that these compounds could be produced from aldehydes and ammonia on the meteorite parent body. This study indicates that the meteoritic amino acids could be synthesized by mechanisms in addition to the Strecker reaction, which has been proposed to be the main synthetic pathway to produce amino acids.

Reaction of cytidine nucleotides with cyanoacetylene: support for the intermediacy of nucleoside-2',3'-cyclic phosphates in the prebiotic synthesis of RNA.

PubMed

Crowe, Michael A; Sutherland, John D

2006-06-01

A robust and prebiotically plausible synthesis of RNA is a key requirement of the "RNA World" hypothesis, but, to date, no such synthesis has been demonstrated. Monomer synthesis strategies involving attachment of preformed nucleobases to sugars have failed, and, even if activated 5'-nucleotides could be made, the hydrolysis of these intermediates in water makes their efficient oligomerisation appear unlikely. We recently reported a synthesis of cytidine-2',3'-cyclic phosphate 1 (C>p) in which the nucleobase was assembled in stages on a sugar-phosphate template. However, 2',3'-cyclic nucleotides (N>p's) also undergo hydrolysis, in this case giving a mixture of the 2'- and 3'-monophosphates. This hydrolysis has previously been seen as making the, otherwise promising, oligomerisation of N>p's seem as unlikely as that of the 5'-activated nucleotides. We now find that cyanoacetylene, the reagent used for the second stage of nucleobase assembly in the synthesis of C>p, also reverses the effect of the hydrolysis by driving efficient cyclisation of C2'p and C3'p back to C>p. Excess cyanoacetylene also derivatises the nucleobase, but this modification is reversible at neutral pH. These findings significantly strengthen the case for N>p's in a prebiotic synthesis of RNA.

Prebiotic materials from on and off the early Earth

PubMed Central

Bernstein, Max

2006-01-01

One of the greatest puzzles of all time is how did life arise? It has been universally presumed that life arose in a soup rich in carbon compounds, but from where did these organic molecules come? In this article, I will review proposed terrestrial sources of prebiotic organic molecules, such as Miller–Urey synthesis (including how they would depend on the oxidation state of the atmosphere) and hydrothermal vents and also input from space. While the former is perhaps better known and more commonly taught in school, we now know that comet and asteroid dust deliver tons of organics to the Earth every day, therefore this flux of reduced carbon from space probably also played a role in making the Earth habitable. We will compare and contrast the types and abundances of organics from on and off the Earth given standard assumptions. Perhaps each process provided specific compounds (amino acids, sugars, amphiphiles) that were directly related to the origin or early evolution of life. In any case, whether planetary, nebular or interstellar, we will consider how one might attempt to distinguish between abiotic organic molecules from actual signs of life as part of a robotic search for life in the Solar System. PMID:17008210

Prebiotic materials from on and off the early Earth.

PubMed

Bernstein, Max

2006-10-29

One of the greatest puzzles of all time is how did life arise? It has been universally presumed that life arose in a soup rich in carbon compounds, but from where did these organic molecules come? In this article, I will review proposed terrestrial sources of prebiotic organic molecules, such as Miller-Urey synthesis (including how they would depend on the oxidation state of the atmosphere) and hydrothermal vents and also input from space. While the former is perhaps better known and more commonly taught in school, we now know that comet and asteroid dust deliver tons of organics to the Earth every day, therefore this flux of reduced carbon from space probably also played a role in making the Earth habitable. We will compare and contrast the types and abundances of organics from on and off the Earth given standard assumptions. Perhaps each process provided specific compounds (amino acids, sugars, amphiphiles) that were directly related to the origin or early evolution of life. In any case, whether planetary, nebular or interstellar, we will consider how one might attempt to distinguish between abiotic organic molecules from actual signs of life as part of a robotic search for life in the Solar System.

Simulating the UV Environment For the Synthesis of Prebiotic Molecules

NASA Astrophysics Data System (ADS)

Ranjan, S.; Sasselov, D.

2014-03-01

UV radiation plays a key role in the era of biogenesis. The young Sun was more UV-active than the modern Sun (Ribas et al. 2010), and the Earth lacked an ozone layer, implying a larger UV flux both on Earth, as well as on asteroids/comets. Ultraviolet radiation can help drive prebiotic molecule synthesis (e.g., Chyba et al. 1992; Powner et al. 2009) or destroy biologically important molecules (e.g., Johns et al. 1967). These effects are wavelength dependent: they are sensitive to ionzation, bond, and ro-vibrational transition energies of biologically relevant molecules and their precursors. When simulating the environment at biogenesis it is therefore important to ensure realistic levels of UV input, in both magnitude and spectral shape. Many laboratory simulations of biomolecule synthesis under prebiotic conditions to date have been done with atomic lamps (e.g., Powner et al. 2007). These lamps are safe, stable, and affordable UV sources, well-suited for initial studies. However, their emission spectra are a poor match to prebiotic conditions: low-pressure lamps are characterized by line emission, while higher-pressure lamps do not well-reproduce the spectrum of the young Sun. In this paper, we present spectra that are more realistic approximations to prebiotic conditions. Using published opacity lists and atmospheric models, we compute the attenuation of the flux from a young Sunanalog due to water, and from the present-day Sun due to a planetary atmosphere. We compare these spectra to those emitted by lamps used in studies today, and explore the potential biological implications of the differences. We conclude by discussing possibilities for better simulating the prebiotic UV environment in lab setups.

A hydrogen-rich early Earth atmosphere.

PubMed

Tian, Feng; Toon, Owen B; Pavlov, Alexander A; De Sterck, H

2005-05-13

We show that the escape of hydrogen from early Earth's atmosphere likely occurred at rates slower by two orders of magnitude than previously thought. The balance between slow hydrogen escape and volcanic outgassing could have maintained a hydrogen mixing ratio of more than 30%. The production of prebiotic organic compounds in such an atmosphere would have been more efficient than either exogenous delivery or synthesis in hydrothermal systems. The organic soup in the oceans and ponds on early Earth would have been a more favorable place for the origin of life than previously thought.

Atmospheric production of glycolaldehyde under hazy prebiotic conditions.

PubMed

Harman, Chester E; Kasting, James F; Wolf, Eric T

2013-04-01

The early Earth's atmosphere, with extremely low levels of molecular oxygen and an appreciable abiotic flux of methane, could have been a source of organic compounds necessary for prebiotic chemistry. Here, we investigate the formation of a key RNA precursor, glycolaldehyde (2-hydroxyacetaldehyde, or GA) using a 1-dimensional photochemical model. Maximum atmospheric production of GA occurs when the CH4:CO2 ratio is close to 0.02. The total atmospheric production rate of GA remains small, only 1 × 10(7) mol yr(-1). Somewhat greater amounts of GA production, up to 2 × 10(8) mol yr(-1), could have been provided by the formose reaction or by direct delivery from space. Even with these additional production mechanisms, open ocean GA concentrations would have remained at or below ~1 μM, much smaller than the 1-2 M concentrations required for prebiotic synthesis routes like those proposed by Powner et al. (Nature 459:239-242, 2009). Additional production or concentration mechanisms for GA, or alternative formation mechanisms for RNA, are needed, if this was indeed how life originated on the early Earth.

Redox Energy and Sulfur Chemistry in Prebiotic Polymer Synthesis and Replication

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1997-01-01

In the past year we have made significant progress in three research areas: (1) Most importantly, we discovered a new pathway of prebiotic amino acid synthesis in which formaldehyde and glycolaldehyde (substrates of the formose reaction) react with ammonia yielding alanine and homoserine in the presence of thiol catalysts. This thiol-dependent synthesis of amino acids undoubtedly occurs via amino acid thioester intermediates capable of forming peptides. This 'one-pot' reaction system operates under mild aqueous conditions, and like modern amino acid biosynthesis, uses sugar intermediates which are converted to amino acids by energy-yielding redox disproportionation. (2) Finally, in preparation for the analysis of Martian meteorite samples, we upgraded our HPLC system and developed an improved method capable of detecting a I femtomole of amino acid enantiomers. (3) We completed our analysis of the energetics of metabolism that revealed that life depends on biosynthetic processes driven by chemical energy made available by the redox disproportionation of carbon groups of sugars. We established that the favorable energy of redox disproportionation is based on the universal reduction potentials of carbon groups. We concluded that it is hard to imagine any other organic molecule besides sugars (formaldehyde oligomers) having the energy and reactivity needed to drive either modem biosynthesis or the chemical processes behind its origin.

Evidence for reactive reduced phosphorus species in the early Archean ocean

PubMed Central

Pasek, Matthew A.; Harnmeijer, Jelte P.; Buick, Roger; Gull, Maheen; Atlas, Zachary

2013-01-01

It has been hypothesized that before the emergence of modern DNA–RNA–protein life, biology evolved from an “RNA world.” However, synthesizing RNA and other organophosphates under plausible early Earth conditions has proved difficult, with the incorporation of phosphorus (P) causing a particular problem because phosphate, where most environmental P resides, is relatively insoluble and unreactive. Recently, it has been proposed that during the Hadean–Archean heavy bombardment by extraterrestrial impactors, meteorites would have provided reactive P in the form of the iron–nickel phosphide mineral schreibersite. This reacts in water, releasing soluble and reactive reduced P species, such as phosphite, that could then be readily incorporated into prebiotic molecules. Here, we report the occurrence of phosphite in early Archean marine carbonates at levels indicating that this was an abundant dissolved species in the ocean before 3.5 Ga. Additionally, we show that schreibersite readily reacts with an aqueous solution of glycerol to generate phosphite and the membrane biomolecule glycerol–phosphate under mild thermal conditions, with this synthesis using a mineral source of P. Phosphite derived from schreibersite was, hence, a plausible reagent in the prebiotic synthesis of phosphorylated biomolecules and was also present on the early Earth in quantities large enough to have affected the redox state of P in the ocean. Phosphorylated biomolecules like RNA may, thus, have first formed from the reaction of reduced P species with the prebiotic organic milieu on the early Earth. PMID:23733935

An efficient process for obtaining prebiotic oligosaccharides derived from lactulose using isomerized and purified whey permeate.

PubMed

Sabater, Carlos; Olano, Agustín; Prodanov, Marin; Montilla, Antonia; Corzo, Nieves

2017-12-01

One of the most promising uses of whey permeate (WP) is the synthesis of prebiotic oligosaccharides. Herein, commercial WP was submitted to chemical isomerization catalysed by sodium borate at an alkaline pH and subsequent purification using anion-exchange resins to remove boron. Subsequently, purified mixtures were used to synthesize prebiotic oligosaccharides using β-galactosidase from Bacillus circulans. Isomerization of concentrated WP (200 g L -1 lactose) gave rise to levels of lactulose up to 155.5 g L -1 after 30 min of reaction (molar ratio of boron/lactose, 1/1; pH 12; 70 °C). Boron was removed from the isomerized WP (IWP) using the combination of a strong acid (IR-120, H + ) and a weak base (IRA-743) anion-exchange resins, reducing its level to <1 ppm, without loss of lactulose. During the transglycosylation reaction of purified IWP (lactose/lactulose ratio, 1/2.4) maximum content of prebiotic compounds was achieved, i.e. 690 g kg -1 WP after 3 h of reaction. This study shows that combined chemical-enzymatic reactions together with the purification of IWP results in an efficient synthesis of prebiotic oligosaccharides. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Stereoselective aminoacylation of RNA

NASA Technical Reports Server (NTRS)

Usher, D. A.; Needels, M. C.; Brenner, T.

1986-01-01

Prebiotic chemistry is faced with a major problem: how could a controlled and selective reaction occur, when there is present in the same solution a large number of alternative possible coreactants? This problem is solved in the modern cell by the presence of enzymes, which are not only highly efficient and controllable catalysts, but which also can impose on their substrates a precise structural requirement. However, enzymes are the result of billions of years of evolution, and we cannot invoke them as prebiotic catalysts. One approach to solving this problem in the prebiotic context is to make use of template-directed reactions. These reactions increase the number of structural requirements that must be simultaneously present in a molecule for it to be able to react, and thereby increase the selectivity of the reaction. They also can give a large increase in the rate of a reaction, if the template constrains two potential coreactants to lie close together. A third benefit is that information that is present in the template molecule can be passed on to the product molecules. If the earliest organisms were based on proteins and nucleic acids, then the investigation of peptide synthesis on an oligonucleotide template is highly relevant to the study of the origin of life.

Structural and electronic properties of barbituric acid and melamine-containing ribonucleosides as plausible components of prebiotic RNA: implications for prebiotic self-assembly.

PubMed

Kaur, Sarabjeet; Sharma, Purshotam; Wetmore, Stacey D

2017-11-22

The RNA world hypothesis assumes that RNA was the first informational polymer that originated from prebiotic chemical soup. However, since the reaction of d-ribose with canonical nucleobases (A, C, G and U) fails to yield ribonucleosides (rNs) in substantial amounts, the spontaneous origin of rNs and the subsequent synthesis of RNA remains an unsolved mystery. To this end, it has been suggested that RNA may have evolved from primitive genetic material (preRNA) composed of simpler prebiotic heterocycles that spontaneously form glycosidic bonds with ribose. As an effort toward evaluating this hypothesis, the present study uses density functional theory (DFT) to assess the suitability of barbituric acid (BA) and melamine (MM) to act as prebiotic nucleobases, both of which have recently been shown to spontaneously form a glycosidic bond with ribose and organize into supramolecular assemblies in solution. The significant strength of hydrogen bonds involving BA and MM indicates that such interactions may have played a crucial role in their preferential selection over competing heterocycles that interact solely through stacking interactions from the primordial soup during the early phase of evolution. However, the greater stability of stacked dimers involving BA or MM and the canonical nucleobases compared to those consisting solely of BA and/or MM points towards the possible evolution of intermediate informational polymers consisting of prebiotic and canonical nucleobases, which could have eventually evolved into RNA. Analysis of the associated rNs reveals an anti conformational preference for the biologically-relevant β-anomer of both BA and MM rNs, which will allow complementary WC-like hydrogen bonding that can stabilize preRNA polymers. Large calculated deglycosylation barriers suggest BA rNs containing C-C glycosidic bonds are relevant in challenging prebiotic environments such as volcanic geotherms, while lower barriers indicate the MM rNs containing C-N-C glycosidic linkages may have been more likely synthesized from simple precursors such as urea-ice in icy (polar) regions. Together, our quantum chemical data clarifies the physicochemical interactions and stability of potential prebiotically-relevant constituents of BA and MM polymeric assemblies, and complements information from previous experimental studies to bolster the candidature of these heterocycles as prebiotic nucleobases.

The relative importance of prebiotic synthesis on the Earth and input from comets and meteorites

NASA Technical Reports Server (NTRS)

Miller, S. L.

1991-01-01

The prebiotic synthesis of hydrogen cyanide and formaldehyde was studied by the action of electric discharges on various model primitive atmospheres containing CH4, CO, and CO2. Photochemical production rates would also have been important and were calculated for HCN and H2CO. A reasonable rate of synthesis of amino acids from these sources is about 10 n moles/(sq cm yr) or 0.10 moles/sq cm in 10(exp 7) yrs. This would give a concentration of 3 x 10(exp -4) M in an ocean of the present size (300 liters/sq cm). The amino acids cannot accumulate over a longer period because the entire ocean passes through the 350 C submarine vents in 10(exp 7) yrs, which decomposes all the organic compounds. A number of workers have calculated the influx of comets and meteorites on the primitive earth, both as a destructive process for organic compounds and for any life that was present, as well as a source of organic compounds. Some of the amino acids from the meteorite proposed to have hit the earth 65 x 10(exp 6) yrs ago were detected at the Cretaceous/Tertiary boundary sediments. The problem with proposing a large scale input of organic compounds from meteorites and comets is that they must survive passage through the atmosphere and impact. There are some processes that would allow survival such as showers of centimeter to meter sized meteorites and various aerodynamic braking processes for larger objects. Even if a significant amount of the organic material survived impact, the destructive processes in the hydrothermal vents would remove these compounds on the average in 10(exp 7) yrs or less. If it is assumed that the input rate was sufficient to overcome these destructive processes, then too much carbon and water, especially from comets, would have been added to the surface of the earth. It was concluded that while some organic material was added to the earth from comets and meteorites, the amount available from these sources at a given time was only a few percent of that from earth based syntheses.

Temperature oscillations near natural nuclear reactor cores and the potential for prebiotic oligomer synthesis.

PubMed

Adam, Zachary R

2016-06-01

Geologic settings capable of driving prebiotic oligomer synthesis reactions remain a relatively unexplored aspect of origins of life research. Natural nuclear reactors are an example of Precambrian energy sources that produced unique temperature fluctuations. Heat transfer models indicate that water-moderated, convectively-cooled natural fission reactors in porous host rocks create temperature oscillations that resemble those employed in polymerase chain reaction (PCR) devices to artificially amplify oligonucleotides. This temperature profile is characterized by short-duration pulses up to 70-100 °C, followed by a sustained period of temperatures in the range of 30-70 °C, and finally a period of relaxation to ambient temperatures until the cycle is restarted by a fresh influx of pore water. For a given reactor configuration, temperature maxima and the time required to relax to ambient temperatures depend most strongly on the aggregate effect of host rock permeability in decreasing the thermal expansion and increasing the viscosity and evaporation temperature of the pore fluids. Once formed, fission-fueled reactors can sustain multi-kilowatt-level power production for 10(5)-10(6) years, ensuring microenvironmental longevity and chemical output. The model outputs indicate that organic synthesis on young planetary bodies with a sizeable reservoir of fissile material can involve more sophisticated energy dissipation pathways than modern terrestrial analog settings alone would suggest.

Project Cassini: a Saturn Orbiter/titan Probe Mission Proposal

NASA Astrophysics Data System (ADS)

Gautier, D.; Ip, W. H.

1984-12-01

Titan is the only moon in the solar system with a substantial atmosphere. The organic chemistry of its N2-CH4 atmosphere may resemble that of the earth's primitive atmosphere before life arose. The investigation of the synthesis of prebiotic molecules in Titan's atmosphere and the atmospheric and surface environments of this planet-sized moon will be the focal point of the Cassini Project proposed to the European Space Agency for an international Saturn Orbiter/Titan Probe mission.

Thermal Studies of Ammonium Cyanide Reactions: A Model for Thermal Alteration of Prebiotic Compounds in Meteorite Parent Bodies

NASA Technical Reports Server (NTRS)

Hammer, P. G.; Locke, D. R.; Burton, A. S.; Callahan, M. P.

2017-01-01

Organic compounds in carbonaceous chondrites were likely transformed by a variety of parent body processes including thermal and aqueous processing. Here, we analyzed ammonium cyanide reactions that were heated at different temperatures and times by multiple analytical techniques. The goal of this study is to better understand the effect of hydrothermal alteration on cyanide chemistry, which is believed to be responsible for the abiotic synthesis of purine nucleobases and their structural analogs detected in carbonaceous chondrites.

Catalytic Role of Manganese Oxides in Prebiotic Nucleobases Synthesis from Formamide.

PubMed

Bhushan, Brij; Nayak, Arunima; Kamaluddin

2016-06-01

Origin of life processes might have begun with the formation of important biomonomers, such as amino acids and nucleotides, from simple molecules present in the prebiotic environment and their subsequent condensation to biopolymers. While studying the prebiotic synthesis of naturally occurring purine and pyrimidine derivatives from formamide, the manganese oxides demonstrated not only good binding for formamide but demonstrated novel catalytic activity. A novel one pot manganese oxide catalyzed synthesis of pyrimidine nucleobases like thymine is reported along with the formation of other nucleobases like purine, 9-(hydroxyacetyl) purine, cytosine, 4(3 H)-pyrimidinone and adenine in acceptable amounts. The work reported is significant in the sense that the synthesis of thymine has exhibited difficulties especially under one pot conditions and also such has been reported only under the catalytic activity of TiO2. The lower oxides of manganese were reported to show higher potential as catalysts and their existence were favored by the reducing atmospheric conditions prevalent on early Earth; thereby confirming the hypothesis that mineral having metals in reduced form might have been more active during the course of chemical evolution. Our results further confirm the role of formamide as a probable precursor for the formation of purine and pyrimidine bases during the course of chemical evolution and origin of life.

Catalytic Diversity in Alkaline Hydrothermal Vent Systems on Ocean Worlds

NASA Astrophysics Data System (ADS)

Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik

2016-10-01

Hydrothermal systems formed by serpentinization can create moderate-temperature, alkaline systems and it is possible that this type of vent could exist on icy worlds such as Europa which have water-rock interfaces. It has been proposed that some prebiotic chemistry responsible for the emergence of life on Earth and possibly other wet and icy worlds could occur as a result ofredox potential and pH gradients in submarine alkaline hydrothermal vents (Russell et al., 2014). Hydrothermal chimneys formed in laboratory simulations of alkaline vents under early Earth conditions have precipitate membranes that contain minerals such as iron sulfides, which are hypothesized to catalyze reduction of CO2 (Yamaguchi et al. 2014, Roldan et al. 2014) leading to further organic synthesis. This CO2 reduction process may be affected by other trace components in the chimney, e.g. nickel or organic molecules. We have conducted experiments to investigate catalytic properties of iron and iron-nickel sulfides containing organic dopants in slightly acidic ocean simulants relevant to early Earth or possibly ocean worlds. We find that the electrochemical properties of the chimney as well as the morphology/chemistry of the precipitate are affected by the concentration and type of organics present. These results imply that synthesis of organics in water-rock systems on ocean worlds may lead to hydrothermal precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent systems.Therefore, further understanding on the electroactive roles of various organic species within hydrothermal chimneys will have important implications for habitability as well as prebiotic chemistry. This work is funded by NASA Astrobiology Institute JPL Icy Worlds Team and a NAI Director's Discretionary Fund award.Yamaguchi A. et al. (2014) Electrochimica Acta, 141, 311-318.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Roldan, A. (2014) Chem. Comm. 51, 35: 7501-7504.

Pre-biotic organic matter from comets and asteroids

NASA Technical Reports Server (NTRS)

Anders, Edward

1989-01-01

Only meteoritic fragments small enough to be gently decelerated by the atmosphere (10 to the -12th g to 10 to the -6th g) can deliver organic matter intact. The amount of such 'soft-landed' organic carbon can be estimated from data for the infall rate of meteoritic matter. At present rates, only about 0.0006 g/sq cm intact organic carbon would accumulate in 100 million years, but at the higher rates of about four billion yr ago, about 20 g/sq cm may have accumulated in the few hundred million years between the last cataclysmic impact and the beginning of life. It may have included some biologically important compounds that did not form by abiotic synthesis on earth.

Orotidine-Containing RNA: Implications for the Hierarchical Selection (Systems Chemistry Emergence) of RNA.

PubMed

Kim, Eun-Kyong; Martin, Vincent; Krishnamurthy, Ramanarayanan

2017-09-12

The prebiotic synthesis of canonical nucleobases from HCN is a cornerstone for the RNA world hypothesis. However, their role in the primordial pathways to RNA is still debated. The very same process starting from HCN also gives rise to orotic acid, which (via orotidine) plays a crucial role in extant biology in the de novo synthesis of uridine and cytidine, the informational base-pairs in RNA. However, orotidine itself is absent in RNA. Given the prebiotic and biological relevance of orotic acid vis-à-vis uracil, we investigated orotidine-containing RNA oligonucleotides and show that they have severely compromised base-pairing properties. While not unexpected, these results suggest that the emergence of extant RNA cannot just be a consequence of the plausible prebiotic formation of its chemical constituents/building blocks. In combination with other investigations on alternative prebiotic nucleobases, sugars, and linkers, these findings imply that the selection of the components of extant RNA occurred at a higher hierarchical level of an oligomer/polymer based on its functional properties-pointing to a systems chemistry emergence of RNA from a library of precursors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alternative bases in the RNA world: the prebiotic synthesis of urazole and its ribosides

NASA Technical Reports Server (NTRS)

Kolb, V. M.; Dworkin, J. P.; Miller, S. L.

1994-01-01

Urazole is a five-membered heterocyclic compound which is isosteric with uracil's hydrogen-bonding segment. Urazole reacts spontaneoulsy with ribose (and other aldoses) to give a mixture of four ribosides: alpha and beta pyranosides and furanosides. This reaction occurs in aqueous solution at mild temperatures. Thermodynamic and kinetic parameters for the reaction of urazole with ribose were determined. In contrast, uracil is completely unreactive with ribose under these conditions. Urazole's unusual reactivity is ascribed to the hydrazine portion of the molecule. Urazole can be synthesized from biuret and hydrazine under prebiotic conditions. The prebiotic synthesis of guanazole, which is isosteric in part to diaminopyrimidine and cytosine, is accomplished from dicyandiamide and hydrazine. Kinetic parameters for both prebiotic reactions were measured. Urazole and guanazole are transparent in the UV, which would be a favorable property in the absence of an ozone layer on the early Earth. Urazole makes hydrogen bonds with adenine in DMSO similar to those of uracil, as established by H NMR. All of these properties make urazole an attractive potential precursor to uracil and guanazole a potential precursor to cytosine in the RNA or pre-RNA world.

XANES Analysis of Organic Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

DTIC Science & Technology

2011-01-01

indicate that they contain molecular precursors of prebiotic interest such as amino acids, nitrile-bearing compounds, and amphiphilic compounds. In...living organisms on Earth remains a mystery. Among the most studied scenarios are those encompassing an extraterres- trial origin of prebiotic ...products of these residues have been partly identified using chromatography techniques, which indicate that they contain molecular precursors of prebiotic

Gas Phase Chemistry and Molecular Complexity: How Far Do They Go?

NASA Astrophysics Data System (ADS)

Balucani, Nadia

2016-07-01

The accumulation of organic molecules of increasing complexity is believed to be an important step toward the emergence of life. But how massive organic synthesis could occur in primitive Earth, i.e. a water-dominated environment, is a matter of debate. Two alternative theories have been suggested so far: endogenous and exogenous synthesis. In the first theory, the synthesis of simple organic molecules having a strong prebiotic potential (simple prebiotic molecules SPMs, such as H2CO, HCN, HC3N, NH2CHO) occurred directly on our planet starting from simple parent molecules of the atmosphere, liquid water and various energy sources. Miller's experiment was a milestone in this theory, but it was later recognized that the complexity of a planet cannot be reproduced in a single laboratory experiment. Some SPMs have been identified in the N2-dominated atmosphere of Titan (a massive moon of Saturn), which is believed to be reminiscent of the primitive terrestrial atmosphere. As such, the atmosphere of Titan represents a planetary scale laboratory for the comprehension of SPM formation in an environment close enough to primitive Earth and is the current frontier in the endogenous theory exploration. In the exogenous theory, SPMs came from space, the carriers being comets, asteroids and meteorites. The rationale behind this suggestion is that plenty of SPMs have been observed in interstellar clouds (ISCs), including star-forming regions, and in small bodies like comets, asteroids and meteorites. Therefore, the basic idea is that SPMs were formed in the solar nebula, preserved during the early phases of the Solar System formation in the body of comets/asteroids/meteorites and finally delivered to Earth by cometary and meteoritic falls. In this contribution, the status of our knowledge on how SPMs can be formed in the gas phase, either in the primitive terrestrial atmosphere or in the cold nebula from which the Solar System originated, will be presented. Particular attention will be given to neutral-neutral reactions.

Oceanic protection of prebiotic organic compounds from UV radiation

NASA Technical Reports Server (NTRS)

Cleaves, H. J.; Miller, S. L.; Bada, J. L. (Principal Investigator)

1998-01-01

It is frequently stated that UV light would cause massive destruction of prebiotic organic compounds because of the absence of an ozone layer. The elevated UV flux of the early sun compounds this problem. This applies to organic compounds of both terrestrial and extraterrestrial origin. Attempts to deal with this problem generally involve atmospheric absorbers. We show here that prebiotic organic polymers as well as several inorganic compounds are sufficient to protect oceanic organic molecules from UV degradation. This aqueous protection is in addition to any atmospheric UV absorbers and should be a ubiquitous planetary phenomenon serving to increase the size of planetary habitable zones.

Prebiotic syntheses of purines and pyrimidines

NASA Technical Reports Server (NTRS)

Basile, B.; Oro, J.; Lazcano, A.

1984-01-01

The results of experimental and theoretical investigations of the prebiotic synthesis of purines and pyramidines are surveyed. Topics examined include the synthesis of purines from HCN via 4,5-disubstituted imidazole derivatives in aqueous solutions or liquid NH3, simultaneous formation of amino acids and purines by electron irradiation of CH4-NH3-H2O mixtures, synthesis of pyrimadines from cynoacetylene, energetics, formation of bases under anhydrous or concentrated conditions, formation of bases under dilute conditions, Fischer-Tropsch-type reactions, and the role of activated intermediates. It is pointed out that the precursor compounds have been detected in the interstellar medium, on Titan, and in other solar-system bodies, and that solar-nebula HCN concentrations of the order of 1-10 mM have been estimated on the basis of meteorite measurements.

Prebiological evolution and the physics of the origin of life

NASA Astrophysics Data System (ADS)

Delaye, Luis; Lazcano, Antonio

2005-03-01

The basic tenet of the heterotrophic theory of the origin of life is that the maintenance and reproduction of the first living systems depended primarily on prebiotically synthesized organic molecules. It is unlikely that any single mechanism can account for the wide range of organic compounds that may have accumulated on the primitive Earth, suggesting that the prebiotic soup was formed by contributions from endogenous syntheses in reducing environments, metal sulphide-mediated synthesis in deep-sea vents, and exogenous sources such as comets, meteorites and interplanetary dust. The wide range of experimental conditions under which amino acids and nucleobases can be synthesized suggests that the abiotic syntheses of these monomers did not take place under a narrow range defined by highly selective reaction conditions, but rather under a wide variety of settings. The robustness of this type of chemistry is supported by the occurrence of most of these biochemical compounds in the Murchison meteorite. These results lend strong credence to the hypothesis that the emergence of life was the outcome of a long, but not necessarily slow, evolutionary processes. The origin of life may be best understood in terms of the dynamics and evolution of sets of chemical replicating entities. Whether such entities were enclosed within membranes is not yet clear, but given the prebiotic availability of amphiphilic compounds this may have well been the case. This scheme is not at odds with the theoretical models of self-organized emerging systems, but what is known of biology suggest that the essential traits of living systems could have not emerged in the absence of genetic material able to store, express and, upon replication, transmit to its progeny information capable of undergoing evolutionary change. How such genetic polymer first evolved is a central issue in origin-of-life studies.

Prebiological evolution and the physics of the origin of life.

PubMed

Delaye, Luis; Lazcano, Antonio

2005-03-01

The basic tenet of the heterotrophic theory of the origin of life is that the maintenance and reproduction of the first living systems depended primarily on prebiotically synthesized organic molecules. It is unlikely that any single mechanism can account for the wide range of organic compounds that may have accumulated on the primitive Earth, suggesting that the prebiotic soup was formed by contributions from endogenous syntheses in reducing environments, metal sulphide-mediated synthesis in deep-sea vents, and exogenous sources such as comets, meteorites and interplanetary dust. The wide range of experimental conditions under which amino acids and nucleobases can be synthesized suggests that the abiotic syntheses of these monomers did not take place under a narrow range defined by highly selective reaction conditions, but rather under a wide variety of settings. The robustness of this type of chemistry is supported by the occurrence of most of these biochemical compounds in the Murchison meteorite. These results lend strong credence to the hypothesis that the emergence of life was the outcome of a long, but not necessarily slow, evolutionary processes. The origin of life may be best understood in terms of the dynamics and evolution of sets of chemical replicating entities. Whether such entities were enclosed within membranes is not yet clear, but given the prebiotic availability of amphiphilic compounds this may have well been the case. This scheme is not at odds with the theoretical models of self-organized emerging systems, but what is known of biology suggest that the essential traits of living systems could have not emerged in the absence of genetic material able to store, express and, upon replication, transmit to its progeny information capable of undergoing evolutionary change. How such genetic polymer first evolved is a central issue in origin-of-life studies.

The Prebiotic Synthesis of Ethylenediamine Monoacetic Acid, The Repeating Unit of Peptide Nucleic Acids

NASA Technical Reports Server (NTRS)

Nelson, Kevin E.; Miller, Stanley L.

1992-01-01

The polymerization of ribonucleic acids or their precursors constitutes an important event in prebiotic chemistry. The various problems using ribonucleotides to make RNA suggest that there may have been a precursor. An attractive possibility are the peptide nucleic acids (PNA). PNAs are nucleotide analogs that make use of a polymer of ethylenediamine monoacetic acid (EDMA or 2-amninoethyl glycine) with the bases attached by an acetic acid. EDMA is an especially attractive alternative to the ribose phosphate or deoxyribose phosphate backbone because it contains no chiral centers and is potentially prebiotic, but there is no reported prebiotic synthesis. We have synthesized both EDMA and ethylenediamine diacetic acid (EDDA) from the prebiotic compounds ethylenediamine, formaldehyde, and hydrogen cyanide. The yields of EDMA range from 11 to 79% along with some sEDDA and uEDDA. These reactions work with concentrations of 10(exp -1)M and as low as 10(exp -4)M, and the reaction is likely to be effective at even lower concentrations. Ethylenediamine is a likely prebiotic compound, but it has not yet been demonstrated, although compounds such as ethanolamine and cysteamine have been proven to be prebiotic. Under neutral pH and heating at l00 C, EDMA is converted to the lactam, monoketopiperazine (MKP). The cyclization occurs and has an approximate ratio of MKP/EDMA = 3 at equilibrium. We have measured the solubilities of EDMA center dot H20 as 6.4 m, EDMA center dot HCl center dot H20 as 13.7 m, and EDMA center dot 2HCl center dot H20 as 3.4 m. These syntheses together with the high solubility of EDMA suggest that EDMA would concentrate in drying lagoons and might efficiently form polymers. Given the instability of ribose and the poor polymerizability of nucleotides, the prebiotic presence of EDMA and the possibility of its polymerization raises the possibility that PNAs are the progenitors of present day nucleic acids. A pre-RNA world may have existed in which PNAs or polymers with related peptide backbones were the dominant information macromolecules.

The Fe-Rich Clay Microsystems in Basalt-Komatiite Lavas: Importance of Fe-Smectites for Pre-Biotic Molecule Catalysis During the Hadean Eon

NASA Astrophysics Data System (ADS)

Meunier, Alain; Petit, Sabine; Cockell, Charles S.; El Albani, Abderrazzak; Beaufort, Daniel

2010-06-01

During the Hadean to early Archean period (4.5-3.5 Ga), the surface of the Earth’s crust was predominantly composed of basalt and komatiite lavas. The conditions imposed by the chemical composition of these rocks favoured the crystallization of Fe-Mg clays rather than that of Al-rich ones (montmorillonite). Fe-Mg clays were formed inside chemical microsystems through sea weathering or hydrothermal alteration, and for the most part, through post-magmatic processes. Indeed, at the end of the cooling stage, Fe-Mg clays precipitated directly from the residual liquid which concentrated in the voids remaining in the crystal framework of the mafic-ultramafic lavas. Nontronite-celadonite and chlorite-saponite covered all the solid surfaces (crystals, glass) and are associated with tiny pyroxene and apatite crystals forming the so-called “mesostasis”. The mesostasis was scattered in the lava body as micro-settings tens of micrometres wide. Thus, every square metre of basalt or komatiite rocks was punctuated by myriads of clay-rich patches, each of them potentially behaving as a single chemical reactor which could concentrate the organics diluted in the ocean water. Considering the high catalytic potentiality of clays, and particularly those of the Fe-rich ones (electron exchangers), it is probable that large parts of the surface of the young Earth participated in the synthesis of prebiotic molecules during the Hadean to early Archean period through innumerable clay-rich micro-settings in the massive parts and the altered surfaces of komatiite and basaltic lavas. This leads us to suggest that Fe,Mg-clays should be preferred to Al-rich ones (montmorillonite) to conduct experiments for the synthesis and the polymerisation of prebiotic molecules.

Synchronized chaotic targeting and acceleration of surface chemistry in prebiotic hydrothermal microenvironments

PubMed Central

Priye, Aashish; Yu, Yuncheng; Hassan, Yassin A.; Ugaz, Victor M.

2017-01-01

Porous mineral formations near subsea alkaline hydrothermal vents embed microenvironments that make them potential hot spots for prebiotic biochemistry. But, synthesis of long-chain macromolecules needed to support higher-order functions in living systems (e.g., polypeptides, proteins, and nucleic acids) cannot occur without enrichment of chemical precursors before initiating polymerization, and identifying a suitable mechanism has become a key unanswered question in the origin of life. Here, we apply simulations and in situ experiments to show how 3D chaotic thermal convection—flows that naturally permeate hydrothermal pore networks—supplies a robust mechanism for focused accumulation at discrete targeted surface sites. This interfacial enrichment is synchronized with bulk homogenization of chemical species, yielding two distinct processes that are seemingly opposed yet synergistically combine to accelerate surface reaction kinetics by several orders of magnitude. Our results suggest that chaotic thermal convection may play a previously unappreciated role in mediating surface-catalyzed synthesis in the prebiotic milieu. PMID:28119504

Structural Elucidation of Enzymatically Synthesized Galacto-oligosaccharides Using Ion-Mobility Spectrometry-Tandem Mass Spectrometry.

PubMed

Carević, Milica; Bezbradica, Dejan; Banjanac, Katarina; Milivojević, Ana; Fanuel, Mathieu; Rogniaux, Hélène; Ropartz, David; Veličković, Dušan

2016-05-11

Galacto-oligosaccharides (GOS) represent a diverse group of well-characterized prebiotic ingredients derived from lactose in a reaction catalyzed with β-galactosidases. Enzymatic transgalactosylation results in a mixture of compounds of various degrees of polymerization and types of linkages. Because structure plays an important role in terms of prebiotic activity, it is of crucial importance to provide an insight into the mechanism of transgalactosylation reaction and occurrence of different types of β-linkages during GOS synthesis. Our study proved that a novel one-step method, based on ion-mobility spectrometry-tandem mass spectrometry (IMS-MS/MS), enables complete elucidation of GOS structure. It has been shown that β-galactosidase from Aspergillus oryzae has the highest affinity toward formation of β-(1→3) or β-(1→6) linkages. Additionally, it was observed that the occurrence of different linkages varies during the reaction course, indicating that tailoring favorable GOS structures with improved prebiotic activity can be achieved by adequate control of enzymatic synthesis.

Chemical evolution and the origin of life

NASA Technical Reports Server (NTRS)

Oro, J.

1983-01-01

A review is presented of recent advances made in the understanding of the formation of carbon compounds in the universe and the occurrence of processes of chemical evolution. Topics discussed include the principle of evolutionary continuity, evolution as a fundamental principle of the physical universe, the nuclear synthesis of biogenic elements, organic cosmochemistry and interstellar molecules, the solar nebula and the solar system in chemical evolution, the giant planets and Titan in chemical evolution, and comets and their interaction with the earth. Also examined are carbonaceous chondrites, environment of the primitive earth, energy sources available on the primitive earth, the synthesis of biochemical monomers and oligomers, the abiotic transcription of nucleotides, unified prebiotic and enzymatic mechanisms, phospholipids and membranes, and protobiological evolution.

Elementary Reactions and Their Role in Gas-Phase Prebiotic Chemistry

PubMed Central

Balucani, Nadia

2009-01-01

The formation of complex organic molecules in a reactor filled with gaseous mixtures possibly reproducing the primitive terrestrial atmosphere and ocean demonstrated more than 50 years ago that inorganic synthesis of prebiotic molecules is possible, provided that some form of energy is provided to the system. After that groundbreaking experiment, gas-phase prebiotic molecules have been observed in a wide variety of extraterrestrial objects (including interstellar clouds, comets and planetary atmospheres) where the physical conditions vary widely. A thorough characterization of the chemical evolution of those objects relies on a multi-disciplinary approach: 1) observations allow us to identify the molecules and their number densities as they are nowadays; 2) the chemistry which lies behind their formation starting from atoms and simple molecules is accounted for by complex reaction networks; 3) for a realistic modeling of such networks, a number of experimental parameters are needed and, therefore, the relevant molecular processes should be fully characterized in laboratory experiments. A survey of the available literature reveals, however, that much information is still lacking if it is true that only a small percentage of the elementary reactions considered in the models have been characterized in laboratory experiments. New experimental approaches to characterize the relevant elementary reactions in laboratory are presented and the implications of the results are discussed. PMID:19564951

Polymersomes containing iron sulfide (FeS) as primordial cell model : for the investigation of energy providing redox reactions.

PubMed

Alpermann, Theodor; Rüdel, Kristin; Rüger, Ronny; Steiniger, Frank; Nietzsche, Sandor; Filiz, Volkan; Förster, Stephan; Fahr, Alfred; Weigand, Wolfgang

2011-04-01

According to Wächtershäuser's "Iron-Sulfur-World" one major requirement for the development of life on the prebiotic Earth is compartmentalization. Vesicles spontaneously formed from amphiphilic components containing a specific set of molecules including sulfide minerals may have lead to the first autotrophic prebiotic units. The iron sulfide minerals may have been formed by geological conversions in the environment of deep-sea volcanos (black smokers), which can be observed even today. Wächtershäuser postulated the evolution of chemical pathways as fundamentals of the origin of life on earth. In contrast to the classical Miller-Urey experiment, depending on external energy sources, the "Iron-Sulfur-World" is based on the catalytic and energy reproducing redox system FeS+H2S-->FeS2+H2. The energy release out of this redox reaction (∆RG°=-38 kJ/mol, pH 0) could be the cause for the subsequent synthesis of complex organic molecules and the precondition for the development of more complex units similar to cells known today. Here we show the possibility for precipitating iron sulfide inside vesicles composed of amphiphilic block-copolymers as a model system for a first prebiotic unit. Our findings could be an indication for a chemoautotrophic FeS based origin of life.

The Propitious Role of Solar Energetic Particles in the Origin of Life

NASA Astrophysics Data System (ADS)

Lingam, Manasvi; Dong, Chuanfei; Fang, Xiaohua; Jakosky, Bruce M.; Loeb, Abraham

2018-01-01

We carry out 3D numerical simulations to assess the penetration and bombardment effects of solar energetic particles (SEPs), i.e., high-energy particle bursts during large flares and superflares, on ancient and current Mars. We demonstrate that the deposition of SEPs is non-uniform at the planetary surface, and that the corresponding energy flux is lower than other sources postulated to have influenced the origin of life. Nevertheless, SEPs may have been capable of facilitating the synthesis of a wide range of vital organic molecules (e.g., nucleobases and amino acids). Owing to the relatively high efficiency of these pathways, the overall yields might be comparable to (or even exceed) the values predicted for some conventional sources such as electrical discharges and exogenous delivery by meteorites. We also suggest that SEPs could have played a role in enabling the initiation of lightning. A notable corollary of our work is that SEPs may constitute an important mechanism for prebiotic synthesis on exoplanets around M-dwarfs, thereby mitigating the deficiency of biologically active ultraviolet radiation on these planets. Although there are several uncertainties associated with (exo)planetary environments and prebiotic chemical pathways, our study illustrates that SEPs represent a potentially important factor in understanding the origin of life.

Stable Carbon Isotopic Signatures of Abiotic Organics from Hydrothermal Synthesis Experiments

NASA Technical Reports Server (NTRS)

Stern, Jennifer C.; Summers, David P.; Kubo, Mike; Yassar, Saima

2006-01-01

Stable carbon isotopes can be powerful biogeochemical markers in the study of life's origins. Biogenic carbon fixation produces organics that are depleted in C-13 by about -20 to -30%0. Less attention has been paid to the isotopic signatures of abiotic processes. The possibility of abiotic processes producing organics with morphologies and isotopic signatures in the biogenic range has been at the center of recent debate over the Earth's earliest microfossils. The abiotic synthesis of organic compounds in hydrothermal environments is one possible source of endogenous organic matter to the prebiotic earth. Simulated hydrothermal settings have been shown to synthesize, among other things, single chain amphiphiles and simple lipids from a mix of CO, CO2, and H2. A key characteristic of these amphiphilic molecules is the ability to self-assemble in aqueous phases into more organized structures called vesicles, which form a selectively permeable boundary and serve the function of containing and concentrating other organic molecules. The ability to form cell like structures also makes these compounds more likely to be mistaken for biogenic. Hydrothermal simulation experiments were conducted from oxalic or formic acid in water at 175 C for 72 hr. The molecular and isotopic composition of the products of these reactions were determined and compared to biogenic fractionations . Preliminary results indicate isotopic fractionation during abiotic hydrocarbon synthesis in hydrothermal environments is on par with biological carbon fixation.

Emergence of biological organization through thermodynamic inversion.

PubMed

Kompanichenko, Vladimir

2014-01-01

Biological organization arises under thermodynamic inversion in prebiotic systems that provide the prevalence of free energy and information contribution over the entropy contribution. The inversion might occur under specific far-from-equilibrium conditions in prebiotic systems oscillating around the bifurcation point. At the inversion moment, (physical) information characteristic of non-biological systems acquires the new features: functionality, purposefulness, and control over the life processes, which transform it into biological information. Random sequences of amino acids and nucleotides, spontaneously synthesized in the prebiotic microsystem, in the primary living unit (probiont) re-assemble into functional sequences, involved into bioinformation circulation through nucleoprotein interaction, resulted in the genetic code emergence. According to the proposed concept, oscillating three-dimensional prebiotic microsystems transformed into probionts in the changeable hydrothermal medium of the early Earth. The inversion concept states that spontaneous (accidental, random) transformations in prebiotic systems cannot produce life; it is only non-spontaneous (perspective, purposeful) transformations, which are the result of thermodynamic inversion, that lead to the negentropy conversion of prebiotic systems into initial living units.

DNA nucleobase synthesis at Titan atmosphere analog by soft X-rays.

PubMed

Pilling, Sergio; Andrade, Diana P P; Neto, Alvaro C; Rittner, Roberto; Naves de Brito, Arnaldo

2009-10-22

Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of N(2) and CH(4) and includes traces of many simple organic compounds. This atmosphere also partly consists of haze and aerosol particles which during the last 4.5 gigayears have been processed by electric discharges, ions, and ionizing photons, being slowly deposited over the Titan surface. In this work, we investigate the possible effects produced by soft X-rays (and secondary electrons) on Titan aerosol analogs in an attempt to simulate some prebiotic photochemistry. The experiments have been performed inside a high vacuum chamber coupled to the soft X-ray spectroscopy beamline at the Brazilian Synchrotron Light Source, Campinas, Brazil. In-situ sample analyses were performed by a Fourier transform infrared spectrometer. The infrared spectra have presented several organic molecules, including nitriles and aromatic CN compounds. After the irradiation, the brownish-orange organic residue (tholin) was analyzed ex-situ by gas chromatographic (GC/MS) and nuclear magnetic resonance ((1)H NMR) techniques, revealing the presence of adenine (C(5)H(5)N(5)), one of the constituents of the DNA molecule. This confirms previous results which showed that the organic chemistry on the Titan surface can be very complex and extremely rich in prebiotic compounds. Molecules like these on the early Earth have found a place to allow life (as we know) to flourish.

A Chemist’s Perspective on the Role of Phosphorus at the Origins of Life

PubMed Central

Fernández-García, Christian; Coggins, Adam J.

2017-01-01

The central role that phosphates play in biological systems, suggests they also played an important role in the emergence of life on Earth. In recent years, numerous important advances have been made towards understanding the influence that phosphates may have had on prebiotic chemistry, and here, we highlight two important aspects of prebiotic phosphate chemistry. Firstly, we discuss prebiotic phosphorylation reactions; we specifically contrast aqueous electrophilic phosphorylation, and aqueous nucleophilic phosphorylation strategies, with dry-state phosphorylations that are mediated by dissociative phosphoryl-transfer. Secondly, we discuss the non-structural roles that phosphates can play in prebiotic chemistry. Here, we focus on the mechanisms by which phosphate has guided prebiotic reactivity through catalysis or buffering effects, to facilitating selective transformations in neutral water. Several prebiotic routes towards the synthesis of nucleotides, amino acids, and core metabolites, that have been facilitated or controlled by phosphate acting as a general acid–base catalyst, pH buffer, or a chemical buffer, are outlined. These facile and subtle mechanisms for incorporation and exploitation of phosphates to orchestrate selective, robust prebiotic chemistry, coupled with the central and universally conserved roles of phosphates in biochemistry, provide an increasingly clear message that understanding phosphate chemistry will be a key element in elucidating the origins of life on Earth. PMID:28703763

Mineral Grains, Dimples, and Hot Volcanic Organic Streams: Dynamic Geological Backstage of Macromolecular Evolution.

PubMed

Skoblikow, Nikolai E; Zimin, Andrei A

2018-04-01

The hypothesis of hot volcanic organic stream as the most probable and geologically plausible environment for abiogenic polycondensation is proposed. The primary synthesis of organic compounds is considered as result of an explosive volcanic (perhaps, meteorite-induced) eruption. The eruption was accompanied by a shock wave propagating in the primeval atmosphere and resulting in the formation of hot cloud of simple organic compounds-aldehydes, alcohols, amines, amino alcohols, nitriles, and amino acids-products, which are usually obtained under the artificial conditions in the spark-discharge experiments. The subsequent cooling of the organic cloud resulted in a gradual condensation and a serial precipitation of organic compounds (in order of decreasing boiling point values) into the liquid phase forming a hot, viscous and muddy organic stream (named "lithorheos"). That stream-even if the time of its existence was short-is considered here as a geologically plausible environment for abiogenic polycondensation. The substances successively prevailing in such a stream were cyanamide, acetamide, formamide, glycolonitrile, acetonitrile. An important role was played by mineral (especially, phosphate-containing) grains (named "lithosomes"), whose surface was modified with heterocyclic nitrogen compounds synthesized in the course of eruption. When such grains got into hot organic streams, their surface catalytic centers (named "lithozymes") played a decisive role in the emergence, facilitation and maintenance of prebiotic reactions and key processes characteristic of living systems. Owing to its cascade structure, the stream was a factor underlying the formation of mineral-polymeric aggregates (named "lithocytes") in the small natural streambed cavities (dimples)-as well as a factor of their further spread within larger geological locations which played a role of chemo-ecological niches. All three main stages of prebiotic evolution (primary organic synthesis, polycondensation, and formation of proto-cellular structures) are combined within a common dynamic geological process. We suppose macromolecular evolution had an extremely fast, "flash" start: the period from volcanic eruption to formation of lithocyte "populations" took not million years but just several tens of minutes. The scenario proposed can be verified experimentally with a three-module setup working with principles of dynamic (flow) chemistry in its core element.

The evolution of organic matter in space.

PubMed

Ehrenfreund, Pascale; Spaans, Marco; Holm, Nils G

2011-02-13

Carbon, and molecules made from it, have already been observed in the early Universe. During cosmic time, many galaxies undergo intense periods of star formation, during which heavy elements like carbon, oxygen, nitrogen, silicon and iron are produced. Also, many complex molecules, from carbon monoxide to polycyclic aromatic hydrocarbons, are detected in these systems, like they are for our own Galaxy. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly high number of molecules that are used in contemporary biochemistry on the Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites and interplanetary dust particles. Large quantities of extra-terrestrial material were delivered via comets and asteroids to young planetary surfaces during the heavy bombardment phase. Monitoring the formation and evolution of organic matter in space is crucial in order to determine the prebiotic reservoirs available to the early Earth. It is equally important to reveal abiotic routes to prebiotic molecules in the Earth environments. Materials from both carbon sources (extra-terrestrial and endogenous) may have contributed to biochemical pathways on the Earth leading to life's origin. The research avenues discussed also guide us to extend our knowledge to other habitable worlds.

Primitive Photosynthetic Architectures Based on Self-Organization and Chemical Evolution of Amino Acids and Metal Ions.

PubMed

Liu, Kai; Ren, Xiaokang; Sun, Jianxuan; Zou, Qianli; Yan, Xuehai

2018-06-01

The emergence of light-energy-utilizing metabolism is likely to be a critical milestone in prebiotic chemistry and the origin of life. However, how the primitive pigment is spontaneously generated still remains unknown. Herein, a primitive pigment model based on adaptive self-organization of amino acids (Cystine, Cys) and metal ions (zinc ion, Zn 2+ ) followed by chemical evolution under hydrothermal conditions is developed. The resulting hybrid microspheres are composed of radially aligned cystine/zinc (Cys/Zn) assembly decorated with carbonate-doped zinc sulfide (C-ZnS) nanocrystals. The part of C-ZnS can work as a light-harvesting antenna to capture ultraviolet and visible light, and use it in various photochemical reactions, including hydrogen (H 2 ) evolution, carbon dioxide (CO 2 ) photoreduction, and reduction of nicotinamide adenine dinucleotide (NAD + ) to nicotinamide adenine dinucleotide hydride (NADH). Additionally, guest molecules (e.g., glutamate dehydrogenase, GDH) can be encapsulated within the hierarchical Cys/Zn framework, which facilitates sustainable photoenzymatic synthesis of glutamate. This study helps deepen insight into the emergent functionality (conversion of light energy) and complexity (hierarchical architecture) from interaction and reaction of prebiotic molecules. The primitive pigment model is also promising to work as an artificial photosynthetic microreactor.

Radiation Processing of Polycyclic Aromatic Hydrocarbons (PAHs) in Space: ICEE PoC

NASA Technical Reports Server (NTRS)

Mattioda, Andrew; Cruz-Diaz, Gustavo; Barnhardt, Michael; Ging, Andrew; Schneider, Todd; Vaughn, Jason; Quigley, Emmett; Phillips, Brandon

2017-01-01

Small Polycyclic Aromatic Hydrocarbon molecules or PAHs (<30 carbon atoms) have been identified in comets, meteorites, asteroids, and interplanetary dust particles in our Solar System, while PAHs in the Interstellar Medium (ISM) tend to be much larger, usually between 50 to 100 carbon atoms in size. The cause of the size disparity between PAHs found in the ISM and Solar System as well as their influence on Solar System organics is not yet understood. Two chemical evolutionary paths have been proposed to explain the inventory of solar system organics. In one the prebiotic material was formed from the radiation induced modification of large pre-solar carbon-bearing species (e.g. ISM PAHs). The second path suggests that Solar System prebiotic matter is the result of bottom-up synthesis from small reactive molecules after the Solar System was formed. In this second scenario very few ISM PAHs survived the harsh pre-solar radiation as aromatic structures. ICEE PoC (ICEE Proof of Concept) investigated factors impacting the chemical evolution of large PAHs irradiated under conditions similar to the proto-solar nebula. Likewise ICEE PoC will refine the technical parameters of the proposed ICEE (Institute for Carbon Evolution Experiment) laboratory.

Towards Self-Replicating Chemical Systems Based on Cytidylic and Guanylic Acids

NASA Technical Reports Server (NTRS)

Kanavarioti, Anastassia

1999-01-01

This project was aimed towards a better understanding of template-directed reactions and, based on this, towards the development of efficient non-enzymatic RNA replicating systems. These systems could serve as models for the prebiotic synthesis of an RNA world. The major objectives of this project are: (a) To elucidate the mechanistic aspects of template-directed (TD) chemistry and (b) to identify active boundary regions, or conditions, environmental and other, that favor "organized chemistry" and stereo-selective polymerization of nucleotides. "Organized chemistry" may lead to enhanced polymerization efficiency which in turn is expected to facilitate the road towards a self-replicating chemical system based on all four nucleic acid bases.

Template-directed synthesis using the heterogeneous templates produced by montmorillonite catalysis. A possible bridge between the prebiotic and RNA worlds

NASA Technical Reports Server (NTRS)

Ertem, G.; Ferris, J. P.

1997-01-01

The synthesis of oligoguanylates [oligo(G)s] is catalyzed by a template of oligocytidylates [oligo(C)s] containing 2',5'- and 3',5'-linked phosphodiester bonds with and without incorporated C5'ppC groupings. An oligo(C) template containing exclusively 2',5'-phosphodiester bonds also serves as a template for the synthesis of complementary oligo(G)s. The oligo(C) template was prepared by the condensation of the 5'-phosphorimidazolide of cytidine on montmorillonite clay. These studies establish that RNA oligomers prepared by mineral catalysis, or other routes on the primitive earth, did not have to be exclusively 3',5'-linked to catalyze template-directed synthesis, since oligo(C)s containing a variety of linkage isomers serve as templates for the formation of complementary oligo(G)s. These findings support the postulate that origin of the RNA world was initiated by the RNA oligomers produced by polymerization of activated monomers formed by prebiotic processes.

A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide.

PubMed

Saladino, Raffaele; Botta, Giorgia; Bizzarri, Bruno Mattia; Di Mauro, Ernesto; Garcia Ruiz, Juan Manuel

2016-05-17

The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818-12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225-256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249-1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746-2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657-662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are clearly specific, demonstrating that the mineral self-assembled membranes at the same time create space compartmentalization and selective catalysis of the synthesis of relevant compounds. Rather than requiring odd local conditions, the prebiotic organic chemistry scenario for the origin of life appears to be common at a universal scale and, most probably, earlier than ever thought for our planet.

The Composition and Organization of Cytoplasm in Prebiotic Cells

PubMed Central

Trevors, Jack T.

2011-01-01

This article discusses the hypothesized composition and organization of cytoplasm in prebiotic cells from a theoretical perspective and also based upon what is currently known about bacterial cytoplasm. It is unknown if the first prebiotic, microscopic scale, cytoplasm was initially contained within a primitive, continuous, semipermeable membrane, or was an uncontained gel substance, that later became enclosed by a continuous membrane. Another possibility is that the first cytoplasm in prebiotic cells and a primitive membrane organized at the same time, permitting a rapid transition to the first cell(s) capable of growth and division, thus assisting with the emergence of life on Earth less than a billion years after the formation of the Earth. It is hypothesized that the organization and composition of cytoplasm progressed initially from an unstructured, microscopic hydrogel to a more complex cytoplasm, that may have been in the volume magnitude of about 0.1–0.2 μm3 (possibly less if a nanocell) prior to the first cell division. PMID:21673913

Experimental determination of photostability and fluorescence-based detection of PAHs on the Martian surface

NASA Astrophysics Data System (ADS)

Dartnell, Lewis R.; Patel, Manish R.; Storrie-Lombardi, Michael C.; Ward, John M.; Muller, Jan-Peter

2012-05-01

Even in the absence of any biosphere on Mars, organic molecules, including polycyclic aromatic hydrocarbons (PAHs), are expected on its surface due to delivery by comets and meteorites of extraterrestrial organics synthesized by astrochemistry, or perhaps in situ synthesis in ancient prebiotic chemistry. Any organic compounds exposed to the unfiltered solar ultraviolet spectrum or oxidizing surface conditions would have been readily destroyed, but discoverable caches of Martian organics may remain shielded in the subsurface or within surface rocks. We have studied the stability of three representative polycyclic aromatic hydrocarbons (PAHs) in a Mars chamber, emulating the ultraviolet spectrum of unfiltered sunlight under temperature and pressure conditions of the Martian surface. Fluorescence spectroscopy is used as a sensitive indicator of remaining PAH concentration for laboratory quantification of molecular degradation rates once exposed on the Martian surface. Fluorescence-based instrumentation has also been proposed as an effective surveying method for prebiotic organics on the Martian surface. We find the representative PAHs, anthracene, pyrene, and perylene, to have persistence half-lives once exposed on the Martian surface of between 25 and 60 h of noontime summer UV irradiation, as measured by fluorescence at their peak excitation wavelength. This equates to between 4 and 9.6 sols when the diurnal cycle of UV light intensity on the Martian surface is taken into account, giving a substantial window of opportunity for detection of organic fluorescence before photodegradation. This study thus supports the use of fluorescence-based instrumentation for surveying recently exposed material (such as from cores or drill tailings) for native Martian organic molecules in rover missions.

Glyceraldehyde and glycolaldehyde in interstellar ice analogues and the role of aldehydes in cosmochemical evolution

NASA Astrophysics Data System (ADS)

Meierhenrich, U.; de Marcellus, P.; Meinert, C.; Myrgorodska, I.; Nahon, L.; Buhse, T.; d'Hendecourt, L.

2015-10-01

Our understanding of the molecular origin of life is based on amino acids, ribose, and nucleobases that - after their selection by prebiotic processes - initiated the evolutionary assembly of catalytic and informational polymers, being proteins and ribonucleic acids. Following previous amino acid identifications in the room-temperature residues of simulated circumstellar/interstellar ices [1,2] we have searched for a different family of molecules of potential prebiotic interest. Using multidimensional gas chromatography coupled to time-of-flight mass spectrometry, we have detected ten aldehydes, including the sugar-related glycolaldehyde and glyceraldehyde - two species considered as key prebiotic intermediates in the first steps toward the synthesis of ribonucleotides in a planetary environment.

Prebiotic inulin: Useful dietary adjuncts to manipulate the livestock gut microflora

PubMed Central

Samanta, A.K.; Jayapal, Natasha; Senani, S.; Kolte, A.P.; Sridhar, Manpal

2013-01-01

In recent years, there has been a growing appreciation on the relevance of gastrointestinal microflora in both ruminants and non-ruminants owing to revelation of their role in several physiological functions including digestion, nutrient utilization, pathogen exclusion, gastrointestinal development, immunity system, gut gene expression and quality of animal products. The ban imposed on the use of antibiotics and hormones in feed has compelled animal researchers in finding an alternative which could overcome the issues of conventional feed additives. Though the concept of prebiotic was evolved keeping in mind the gastrointestinal flora of human beings, presently animal researchers are exploring the efficiency of prebiotic (inulin) for modulating the gut ecosystem of both ruminants and non-ruminants. It was revealed that prebiotic inulin is found to exhibit desirable changes in the gut of non-ruminants like poultry, swine, rabbit etc for augmenting gut health and improvement of product quality. Similarly, in ruminants the prebiotic reduces rumen ammonia nitrogen, methane production, increase microbial protein synthesis and live weight gains in calves. Unlike other feed additives, prebiotic exhibits its effect in multipronged ways for overall increase in the performances of the animals. In coming days, it is expected that prebiotics could be the part of diets in both ruminants and non-ruminants for enabling modulation of gut microflora vis a vis animals productivity in ecological ways. PMID:24159277

Radioactivity as a significant energy source in prebiotic synthesis.

PubMed

Garzón, L; Garzón, M L

2001-01-01

Radioactivity in the continental crust (due mainly to the isotopes 238U, 235U, 232Th and 40K), as a energy source for chemical evolution in the early Archean (between 3.5 and approximately 4 Ga bp), is reviewed. The most important radioactive source in the continental crust is due to the production and accumulation of radioactive gases within the crust voids (porosity). The study of such mechanism has allowed us to reach a deeper understanding about the nature of the radioactive source and to describe its behavior, particularly with regard to prebiotic chemical evolution. An effective total energy of 3 x 10(18) Ja-1 has been obtained for a depth of 1 km, 4 Ga ago. If a depth of 30 km is taken, the obtained value is almost equal to the UV solar energy radiation (lambda < 150 nm). Within the voids the radioactive source of the continental crust played a relevant role in prebiotic synthesis. In uranium deposits of the same age, the role of radioactivity must have been even more relevant in favoring chemical evolution.

Inversion Concept of the Origin of Life

NASA Astrophysics Data System (ADS)

Kompanichenko, V. N.

2012-06-01

The essence of the inversion concept of the origin of life can be narrowed down to the following theses: 1) thermodynamic inversion is the key transformation of prebiotic microsystems leading to their transition into primary forms of life; 2) this transformation might occur only in the microsystems oscillating around the bifurcation point under far-from-equilibrium conditions. The transformation consists in the inversion of the balance "free energy contribution / entropy contribution", from negative to positive values. At the inversion moment the microsystem radically reorganizes in accordance with the new negentropy (i.e. biological) way of organization. According to this approach, the origin-of-life process on the early Earth took place in the fluctuating hydrothermal medium. The process occurred in two successive stages: a) spontaneous self-assembly of initial three-dimensional prebiotic microsystems composed mainly of hydrocarbons, lipids and simple amino acids, or their precursors, within the temperature interval of 100-300°C (prebiotic stage); b) non-spontaneous synthesis of sugars, ATP and nucleic acids started at the inversion moment under the temperature 70-100°C (biotic stage). Macro- and microfluctuations of thermodynamic and physico-chemical parameters able to sustain this way of chemical conversion have been detected in several contemporary hydrothermal systems. A minimal self-sufficient unit of life on the early Earth was a community of simplest microorganisms (not a separate microorganism).

ISSOL Meeting, 7th, Barcelona, Spain, July 4-9, 1993. [Abstracts only

NASA Technical Reports Server (NTRS)

Ferris, James P. (Editor)

1994-01-01

The journal issue consists of abstracts presented at the International Society for the Study of the Origins of Life (ISSOL) conference. Topics include research on biological and chemical evolution including prebiotic evolution: cosmic and terrestrial; mechanisms of abiogenesis including synthesis and reactions of biomonomers; and analysis of cometary matter and its possible relationship to organic compounds on Earth. Theories and research on origins of ribonucleic acids (RNA), deoxyribonucleic acid (DNA), and other amino acids and complex proteins including their autocatalysis, replication, and translation are presented. Abiotic synthesis of biopolymers, mechanisms of the Genetic Code, precellular membrane systems and energetics are considered. Earth planetary evolution including early microfossils and geochemical conditions and simulations to study these conditions are discussed. The role of chirality in precellular evolution and the taxonomy and phylogeny of very simple organisms are reported. Past and future explorations in exobiology and space research directed toward study of the origins of life and solar system evolution are described.

Organic Minerals in the Origin of Life

NASA Astrophysics Data System (ADS)

Benner, S.; Biondi, E.; Kim, H. J.

2017-12-01

Models for the origin of life are plagued by fundamental problems that, due to their difficulty, are called "paradoxes". One of these, known to anyone who has ever worked in a kitchen, is that organics, when given energy and left to itself, does not generate life. Rather, organics devolve to give tarry mixtures that become increasingly complex and increasingly less likely to support life (like asphalt). However, even if those mixtures escape devolution to create something useful for Darwinism, like building blocks for RNA, the water in which they must work is corrosive, leading to their destruction. Even if RNA is created, it is itself easily degraded. One current trend to manage those paradoxes turns to minerals in environments on early Earth. Inorganic minerals containing borate have now been shown to prevent the destruction of ribose (the R in RNA) and other carbohydrates essential for early Earth. Evaporite desert basins supplied with aqueous runoff from tourmaline-containing basalts are ideal environments for forming borate minerals, especially if they are made alkaline by serpentinizing peridotite. In the evaporite environments, drying cycles mitigate the destructive capability of water. Further, we have shown that phosphate is segregated from calcium (avoiding formation of relatively unreacted apatites) if magnesium and borate are present. Further, a common magnesium borophosphate (luneburgite) not only makes phosphate available for prebiotic synthesis, but selectively phosphorylates RNA building blocks as it releases borate to stabilize them against further degradation. Finally, a variety of minerals bind and stabilize RNA itself. Research in this area has also discovered organic minerals that might have been relevant to the origins of life on Earth. Such minerals are scarce on Earth today, since they are easily consumed by microbial communities. However, on a prebiotic Earth, organic minerals could have stored organic species as intermediates towards our nine, in preparation for their use in key steps on probiotic synthesis. This prevents a model from needing to do everything from start to finish at the same time. This talk will review current progress in this area, and show how it is confirmed by recent Mars exploration on Gail crater, which may resemble the environment on early Earth where life originated.

Carbon Monoxide and the Potential for Prebiotic Chemistry on Habitable Planets around Main Sequence M Stars.

PubMed

Nava-Sedeño, J Manik; Ortiz-Cervantes, Adrian; Segura, Antígona; Domagal-Goldman, Shawn D

2016-10-04

Lifeless planets with CO 2 atmospheres produce CO by CO 2 photolysis. On planets around M dwarfs, CO is a long-lived atmospheric compound, as long as UV emission due to the star's chromospheric activity lasts, and the sink of CO and O 2 in seawater is small compared to its atmospheric production. Atmospheres containing reduced compounds, like CO, may undergo further energetic and chemical processing to give rise to organic compounds of potential importance for the origin of life. We calculated the yield of organic compounds from CO 2 -rich atmospheres of planets orbiting M dwarf stars, which were previously simulated by Domagal-Goldman et al. (2014) and Harman et al. (2015), by cosmic rays and lightning using results of experiments by Miyakawa et al. (2002) and Schlesinger and Miller ( 1983a , 1983b ). Stellar protons from active stars may be important energy sources for abiotic synthesis and increase production rates of biological compounds by at least 2 orders of magnitude compared to cosmic rays. Simple compounds such as HCN and H 2 CO are more readily synthesized than more complex ones, such as amino acids and uracil (considered here as an example), resulting in higher yields for the former and lower yields for the latter. Electric discharges are most efficient when a reducing atmosphere is present. Nonetheless, atmospheres with high quantities of CO 2 are capable of producing higher amounts of prebiotic compounds, given that CO is constantly produced in the atmosphere. Our results further support planetary systems around M dwarf stars as candidates for supporting life or its origin. Key Words: Prebiotic chemistry-M dwarfs-Habitable planets-Cosmic rays-Lightning-Stellar activity. Astrobiology 16, 744-754.

Prebiotic Synthesis of Vitamin B6-type Compounds

NASA Astrophysics Data System (ADS)

Austin, Sabrina M.; Waddell, Thomas G.

1999-05-01

Heating a dilute solution of NH3 and glycoaldehyde gives a large family of pyridines substituted with the same functional groups as occur in the forms of vitamin B6. Thus, vitamin B6-like molecules could have been present on the early Earth and could have been available for catalysis of primitive transamination reactions. Ethanolamine and N-methylethanolamine are also formed as major products. These are choline-like molecules, the latter of which is apparently formed by a prebiotic methylation process.

Exploration in the Complexity of Possible Life: Abstracting and Synthesizing the Principles of Living Systems - Proceedings of the German Workshop on Artificial Life (7th) Held in Jena, Germany on 26-28 Jul 2006

DTIC Science & Technology

2006-01-01

artificial chemistry. 1 Introduction Chemical evolution (i.e., prebiotic evolution) is concerned with the period of life’s history that precedes the...arrival of the first living organism [17]. Since Miller’s pioneering work [19, 20], prebiotic chemistry has been studied in various laboratory...Bada. The 1953 Stanley L. Miller experiment: fifty years of prebiotic organic chemistry. Orig Life Evol Biosph, 33(3):235–42, 2003. 145 [17] J. Maynard

Prebiotic Peptide (Amide) Bond Synthesis Accelerated by Glycerol and Bicarbonate Under Neutral to Alkaline Dry-Down Conditions

NASA Astrophysics Data System (ADS)

Forsythe, J. G.; Weber, A. L.

2017-07-01

We report a new process for robust peptide bond synthesis in the pH 6–10 range that involves dry-down heating of amino acids in the presence of glycerol and bicarbonate (substrates: L-alanine, L-2-aminobutyric acid, β-alanine, isoserine).

Prebiotics and Bone.

PubMed

Whisner, Corrie M; Weaver, Connie M

2017-01-01

Recent advancements in food science have resulted in the extraction and synthesis of novel dietary fibers or prebiotics. Subsequently, great interest has emerged in developing strategies to improve metabolic conditions like osteoporosis by modulating the intestinal microbiome with fiber. Prebiotics have been shown to increase calcium absorption in the lower gut of both animals and humans as well as improve measures of bone mineral density and strength in rodent models. Fewer data are available in humans, but data from growing children and postmenopausal women suggest that prebiotics have both short- and long-term effects that beneficially affect bone turnover and mineral accretion in the skeleton. Currently, the exact mechanism by which these products elicit their effects on bone is poorly understood, but emerging data suggest that the gut microbiota may be involved in one or more direct and indirect pathways. The most well-accepted mechanism is through microbial fermentation of prebiotics which results in the production of short-chain fatty acids and a concomitant decrease in pH which increases the bioavailability of calcium in the colon. While other mechanisms may be eliciting a prebiotic effect on bone, the current data suggest that novel dietary fibers may be an affordable and effective method of maximizing mineral accretion in growing children and preventing bone loss in later years when osteoporosis is a greater risk. This chapter will discuss the dynamic role of prebiotics in bone health by discussing the current state of the art, addressing gaps in knowledge and their role in public health.

Recent Advances in Supramolecular Assemblies with Nucleic Acids

DTIC Science & Technology

2007-08-29

origin of life“ Abstract : A large number of surfactants are chemically simple compounds that may be obtained under presumably prebiotic ...world hypothesis), it is still unclear how RNA could have been formed under prebiotic conditions. Surfactants with their self-organizing properties may...surfactants were possibly very important in prebiotic times in the sense that they may have been involved in different physical and chemical

Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

NASA Technical Reports Server (NTRS)

Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

Prebiotic Chemistry: Geochemical Context and Reaction Screening

PubMed Central

Cleaves, Henderson James

2013-01-01

The origin of life on Earth is widely believed to have required the reactions of organic compounds and their self- and/or environmental organization. What those compounds were remains open to debate, as do the environment in and process or processes by which they became organized. Prebiotic chemistry is the systematic organized study of these phenomena. It is difficult to study poorly defined phenomena, and research has focused on producing compounds and structures familiar to contemporary biochemistry, which may or may not have been crucial for the origin of life. Given our ignorance, it may be instructive to explore the extreme regions of known and future investigations of prebiotic chemistry, where reactions fail, that will relate them to or exclude them from plausible environments where they could occur. Come critical parameters which most deserve investigation are discussed. PMID:25369745

Efficient synthesis and activity of beneficial intestinal flora of two lactulose-derived oligosaccharides.

PubMed

Zhu, Zhen-Yuan; Cui, Di; Gao, Hui; Dong, Feng-Ying; Liu, Xiao-cui; Liu, Fei; Chen, Lu; Zhang, Yong-min

2016-05-23

Lactulose is considered as a prebiotic because it promotes the intestinal proliferation of Lactobacillus acidophilus which is added to various milk products. Moreover, lactulose is used in pharmaceuticals as a gentle laxative and to treat hyperammonemia. This study was aimed at the total synthesis of two Lactulose-derived oligosaccharides: one is 3-O-β-d-galactopyranosyl-d-fructose, d-fructose and β-d-galactose bounded together with β-1,3-glycosidic bound, the other is 1-O-β-d-galactopyranosyl-d-fructose, d-fructose and β-d-galactose bounded together with β-1,1-glycosidic bound, which were accomplished in seven steps from d-fructose and β-d-galactose and every step of yield above 75%. This synthetic route provided a practical and effective synthetic strategy for galactooligosaccharides, starting from commercially available monosaccharides. Then we evaluated on their prebiotic properties in the search for potential agents of regulating and improving the intestinal flora of human. The result showed that the prebiotic properties of Lactulose-derived oligosaccharides was much better than Lactulose. Among them, 3-O-β-d-galactopyranosyl-d-fructose displayed the most potent activity of proliferation of L. acidophilus. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Effect of prebiotic fibre supplementation on hepatic gene expression and serum lipids: a dose–response study in JCR:LA-cp rats

PubMed Central

Parnell, Jill A.; Reimer, Raylene A.

2013-01-01

Prebiotic fibres have been proposed to promote weight loss and lower serum cholesterol; however, the mechanisms are not fully understood. The aim of the present research was to identify possible mechanisms through which prebiotic fibres improve serum lipids. Lean and obese JCR:La-cp rats aged 8 weeks consumed one of three diets supplemented with 0, 10 or 20 % prebiotic fibre for 10 weeks. Rats were anaesthetised and a fasting blood sample was taken for lipid analysis. Real-time PCR was used to determine gene expression for cholesterol and fatty acid regulatory genes in liver tissue. Liver and caecal digesta cholesterol and TAG content were quantified. Both doses of prebiotic fibre lowered serum cholesterol levels by 24 % in the obese hyperlipidaemic rats (P<0·05). This change was associated with an increase in caecal digesta as well as an up-regulation of genes involved in cholesterol synthesis and bile production. Additionally, there was a 42 % reduction in TAG accumulation in the liver of the obese rats with 10 % prebiotic diet (P<0·05); however, no change in liver fatty acid synthase (FAS). Prebiotic fibres appear to lower cholesterol levels through increased cholesterol excretion in the form of bile and inhibit the accumulation of TAG in the liver through a mechanism unrelated to FAS. These effects appear to be limited to the obese model and particularly the 10 % dose. The present work is significant as it provides insight into the mechanisms of action for prebiotic fibres on lipid metabolism and furthers the development of dietary treatments for hypercholesterolaemia. PMID:20021705

A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide

PubMed Central

2016-01-01

The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818–12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225–256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249–1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746–2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657–662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are clearly specific, demonstrating that the mineral self-assembled membranes at the same time create space compartmentalization and selective catalysis of the synthesis of relevant compounds. Rather than requiring odd local conditions, the prebiotic organic chemistry scenario for the origin of life appears to be common at a universal scale and, most probably, earlier than ever thought for our planet. PMID:27115539

Synbiotics, probiotics or prebiotics in infant formula for full term infants: a systematic review

PubMed Central

2012-01-01

Background Synbiotics, probiotics or prebiotics are being added to infant formula to promote growth and development in infants. Previous reviews (2007 to 2011) on term infants given probiotics or prebiotics focused on prevention of allergic disease and food hypersensitivity. This review focused on growth and clinical outcomes in term infants fed only infant formula containing synbiotics, probiotics or prebiotics. Methods Cochrane methodology was followed using randomized controlled trials (RCTs) which compared term infant formula containing probiotics, prebiotics or synbiotics to conventional infant formula with / without placebo among healthy full term infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Where appropriate, meta-analysis was performed; heterogeneity was explored using subgroup and sensitivity analyses. If studies were too diverse a narrative synthesis was provided. Results Three synbiotic studies (N = 475), 10 probiotics studies (N = 933) and 12 prebiotics studies (N = 1563) were included. Synbiotics failed to significantly increase growth in boys and girls. Use of synbiotics increased stool frequency, had no impact on stool consistency, colic, spitting up / regurgitation, crying, restlessness or vomiting. Probiotics in formula also failed to have any significant effect on growth, stool frequency or consistency. Probiotics did not lower the incidence of diarrhoea, colic, spitting up / regurgitation, crying, restlessness or vomiting. Prebiotics in formula did increase weight gain but had no impact on length or head circumference gain. Prebiotics increased stool frequency but had no impact on stool consistency, the incidence of colic, spitting up / regurgitation, crying, restlessness or vomiting. There was no impact of prebiotics on the volume of formula tolerated, infections and gastrointestinal microflora. The quality of evidence was compromised by imprecision, inconsistency of results, use of different study preparations and publication bias. Authors’ conclusions There is not enough evidence to state that supplementation of term infant formula with synbiotics, probiotics or prebiotics does result in improved growth or clinical outcomes in term infants. There is no data available to establish if synbiotics are superior to probiotics or prebiotics. PMID:23035863

Synbiotics, probiotics or prebiotics in infant formula for full term infants: a systematic review.

PubMed

Mugambi, Mary N; Musekiwa, Alfred; Lombard, Martani; Young, Taryn; Blaauw, Reneé

2012-10-04

Synbiotics, probiotics or prebiotics are being added to infant formula to promote growth and development in infants. Previous reviews (2007 to 2011) on term infants given probiotics or prebiotics focused on prevention of allergic disease and food hypersensitivity. This review focused on growth and clinical outcomes in term infants fed only infant formula containing synbiotics, probiotics or prebiotics. Cochrane methodology was followed using randomized controlled trials (RCTs) which compared term infant formula containing probiotics, prebiotics or synbiotics to conventional infant formula with / without placebo among healthy full term infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Where appropriate, meta-analysis was performed; heterogeneity was explored using subgroup and sensitivity analyses. If studies were too diverse a narrative synthesis was provided. Three synbiotic studies (N = 475), 10 probiotics studies (N = 933) and 12 prebiotics studies (N = 1563) were included. Synbiotics failed to significantly increase growth in boys and girls. Use of synbiotics increased stool frequency, had no impact on stool consistency, colic, spitting up / regurgitation, crying, restlessness or vomiting. Probiotics in formula also failed to have any significant effect on growth, stool frequency or consistency. Probiotics did not lower the incidence of diarrhoea, colic, spitting up / regurgitation, crying, restlessness or vomiting. Prebiotics in formula did increase weight gain but had no impact on length or head circumference gain. Prebiotics increased stool frequency but had no impact on stool consistency, the incidence of colic, spitting up / regurgitation, crying, restlessness or vomiting. There was no impact of prebiotics on the volume of formula tolerated, infections and gastrointestinal microflora. The quality of evidence was compromised by imprecision, inconsistency of results, use of different study preparations and publication bias. There is not enough evidence to state that supplementation of term infant formula with synbiotics, probiotics or prebiotics does result in improved growth or clinical outcomes in term infants. There is no data available to establish if synbiotics are superior to probiotics or prebiotics.

Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1998-01-01

Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.

Acquisition of a Gas Chromatograph/Mass Spectrometer System for Laboratory Study of Prebiotic Organic Geochemical Processes on the Early Earth, Mars, and Meteorites

NASA Technical Reports Server (NTRS)

McCollom, Thomas

2004-01-01

This was a major equipment grant that provided funds ($72K) for purchase of a benchtop gas chromatograph-mass spectrometer (GC-MS) for use in experimental studies of prebiotic organic compounds. An Agilent model 689015973 GC-MS was purchased and installed in the PI's lab in August of 2003. The instrument is now being used for a variety of research projects. The primary use of the instrument is to analyze and quantify organic products of laboratory experiments conducted by the PI. One example is shown, which shows organic products (predominantly n-alkanes) formed during Fischer-Tropsch-type abiotic synthesis under hydrothermal conditions. The analytical capabilities of the GC- MS allowed identification of the numerous organic products of this as well as other laboratory experiments. A key use of the instrument in this research is that the mass spectrometer capabilities allow use of isotopically labeled reactants to trace the progress of reactions and evaluate background contaminants. collaborative projects with other scientists involved in exobiology & astrobiology research (e.g., Mitch Schulte, NASA Ames; Katrina Edwards, Woods Hole Oceanographic Institution). For instance, an analysis of membrane lipids of an lithoautotrophic iron-oxidizing bacteria being grown on basalt as a source of metabolic energy, a project where the instrument is being used to evaluate possible biomarker compounds from these organisms is shown. These iron oxidizers are thought to be similar to those living within the ocean crust, and are being investigated as possible analog organisms to those on the early Earth or crust of Mars. The instrument has also been used by an outside investigator (graduate student Brandon Canfeld, Arizona State University) for identification and isotopic characterization of experimental products of abiotic organic synthesis experiments he is conducting with Dr. John Holloway. analysis of quality control samples for other NASA-funded projects. For instance, an analysis of residual hydrocarbon contaminants on the internal surface of the shell of an atmospheric sounding rocket is shown. This analysis was used to help determine the source of the contaminating compounds. In the future, the instrument will continue to be used for quality control analysis in clean rooms and instrument construction facilities within the Laboratory for Atmospheric and Space Physics, where the GC-MS is housed.

Stereoselective differentiation in the Salt-induced Peptide Formation reaction and its relevance for the origin of life.

PubMed

Plankensteiner, Kristof; Reiner, Hannes; Rode, Bernd M

2005-04-01

All living organisms on earth are almost totally made up of biomolecules of only one chiral form. For example, proteins are built almost exclusively of L-amino acids, and sugars are composed of D-saccharides, a fact that is usually referred to as biohomochirality. Its origin is the center of numerous investigations and theories but is not really elucidated yet. The results of experimental investigations of peptide formation in a prebiotically relevant scenario, as described in this paper, give indications on a possible pathway for the synthesis of homochiral L-peptides in the course of the Salt-induced Peptide Formation (SIPF) reaction.

Chiral Sugars Drive Enantioenrichment in Prebiotic Amino Acid Synthesis.

PubMed

Wagner, Alexander J; Zubarev, Dmitry Yu; Aspuru-Guzik, Alán; Blackmond, Donna G

2017-04-26

Chiral pentose sugars mediate the enantioselective synthesis of amino acid precursors, with the magnitude of the chiral induction dictated by a subtle cooperativity between sugar hydroxyl groups. Ribose and lyxose give opposite chiral preferences, and theoretical calculations reveal the pseudoenantiomeric nature of transition state structures from the two sugars. Prebiotically plausible mixtures of natural d-sugars lead to enantioenrichment of natural l-amino acid precursors. Temporal monitoring and kinetic modeling of the reaction reveal an unusual dynamic kinetic resolution that shifts toward an enantioselective pathway over time, providing an amplification mechanism for the transfer of chiral information. This work adds to growing evidence for synergy in the etiology of the single chirality of the two most important classes of biological molecules, the sugars that make up DNA and RNA and the amino acids that form proteins.

Chiral Sugars Drive Enantioenrichment in Prebiotic Amino Acid Synthesis

PubMed Central

2017-01-01

Chiral pentose sugars mediate the enantioselective synthesis of amino acid precursors, with the magnitude of the chiral induction dictated by a subtle cooperativity between sugar hydroxyl groups. Ribose and lyxose give opposite chiral preferences, and theoretical calculations reveal the pseudoenantiomeric nature of transition state structures from the two sugars. Prebiotically plausible mixtures of natural d-sugars lead to enantioenrichment of natural l-amino acid precursors. Temporal monitoring and kinetic modeling of the reaction reveal an unusual dynamic kinetic resolution that shifts toward an enantioselective pathway over time, providing an amplification mechanism for the transfer of chiral information. This work adds to growing evidence for synergy in the etiology of the single chirality of the two most important classes of biological molecules, the sugars that make up DNA and RNA and the amino acids that form proteins. PMID:28470050

Life sciences and space research XXI(2); Proceedings of the Seventh and Eleventh Workshops, Graz, Austria, June 25-July 7, 1984

NASA Technical Reports Server (NTRS)

Oser, H. (Editor); Oro, J. (Editor); Macelroy, R. D. (Editor); Klein, H. P. (Editor); Devincenzi, D. L. (Editor); Young, R. S. (Editor)

1984-01-01

Space-based and space-related research in the life sciences is presented in reviews and reports. Topics examined include the long-term effects of weightlessness, cosmic chemistry and chemical and biological evolution, life-support systems for space travel, planetary protection, and the g-scale factor in gravitational biology. Consideration is given to the role of Ca ions in cytological effects of hypogravity, the organic aerosols of Titan, the role of meteorite impacts in the formation of organic molecules, prebiotic synthesis of purines and pyrimidines, atmosphere behavior of gas-closed mouse-algal systems, air and water regeneration in advanced regenerative environmental-control and life-support systems, and the influence of gravity on the development of animal systems.

Extraterrestrial flux of potentially prebiotic C, N, and P to the early Earth.

PubMed

Pasek, Matthew; Lauretta, Dante

2008-02-01

With growing evidence for a heavy bombardment period ending 4-3.8 billion years ago, meteorites and comets may have been an important source of prebiotic carbon, nitrogen, and phosphorus on the early Earth. Life may have originated shortly after the late-heavy bombardment, when concentrations of organic compounds and reactive phosphorus were enough to "kick life into gear". This work quantifies the sources of potentially prebiotic, extraterrestrial C, N, and P and correlates these fluxes with a comparison to total Ir fluxes, and estimates the effect of atmosphere on the survival of material. We find (1) that carbonaceous chondrites were not a good source of organic compounds, but interplanetary dust particles provided a constant, steady flux of organic compounds to the surface of the Earth, (2) extraterrestrial metallic material was much more abundant on the early Earth, and delivered reactive P in the form of phosphide minerals to the Earth's surface, and (3) large impacts provided substantial local enrichments of potentially prebiotic reagents. These results help elucidate the potential role of extraterrestrial matter in the origin of life.

Design of the TMT Mid-Infrared Echelle: Science Drivers and Design Overview

DTIC Science & Technology

2006-01-01

plausibility of an extra-terrestrial origin for the prebiotic compounds that led to the emergence of life on Earth. MIRES imaging of debris disks will...explore mechanisms by which water and prebiotic organic compounds may have been delivered to planetary surfaces. These studies will be highly synergistic...that are precursors to complex prebiotic compounds. The high sensitivity also allows the exploration of a wider range of wavelengths, including those

Models of glycolysis: Glyceraldehyde as a source of energy and monomers for prebiotic condensation reactions

NASA Technical Reports Server (NTRS)

Weber, A. L.

1986-01-01

All organisms require energy in a chemical form for maintenance and growth. In contemporary life this chemical energy is obtained by the synthesis of the phosphoanhydride bonds of ATP. Among the biological processes that yield ATP, fermentation is generally considered primitive, because it operates under anaerobic conditions by substrate-level phosphorylation which does not require compartmentation by membranes. Fermentation by the glycolytic pathway, which is found in almost every living cell, is an especially attractive energy source for primitive life. Glycolysis not only produces useful chemical energy (ATP), but intermediates of this pathway are also involved in amino acid synthesis and photosynthetic carbon-fixation. It is believed that energy and substrates needed for the origin of life were provided by nonenzymatic chemical reactions that resemble the enzyme-mediated reactions of glycolysis. These nonenzymatic reactions would have provided a starting point for the evolutionary development of glycolysis.

A New Energy Source for Organic Synthesis in Europa's Surface Ice

NASA Technical Reports Server (NTRS)

Borucki, Jerome G.; Khare, Bishun; Cruikshank, Dale P.; DeVincenzi, D. (Technical Monitor)

2002-01-01

Colored regions on Jupiter's satellite Europa and other icy bodies in the outer Solar System may be contaminated by organic macromolecular solid material that is produced when surface ices are exposed to electrical energy. Hypervelocity meteorite impacts and fracture release tidal and tectonic stresses in icy crusts in the form of electrical discharges, which provide the energy for in situ synthesis of the organic solids. We report measurements of electrical discharge, light emission, and magnetic phenomena in hypervelocity impacts into ice with projectiles with V approx. 5 km/s. Part of the projectile's kinetic energy is converted into electrical potential, while the mechanical disruption of the impact also releases stress energy as light, heat, electrical, and magnetic fields as secondary emissions. These newly recognized energy sources suggest that the dark material in the area of impact craters are tholins generated from the energy of the impacts and that well up from the fracture zone. Large pools of liquid water would persist under the meteorite crater for thousands of years, with the potential for prebiotic chemistry to take place at an accelerated rate due to energy pumped in from the secondary emissions.

Potential prebiotic properties of cashew apple (Anacardium occidentale L.) agro-industrial byproduct on Lactobacillus species.

PubMed

Duarte, Francisca Nayara Dantas; Rodrigues, Jéssica Bezerra; da Costa Lima, Maiara; Lima, Marcos Dos Santos; Pacheco, Maria Teresa Bertoldo; Pintado, Maria Manuela Estevez; de Souza Aquino, Jailane; de Souza, Evandro Leite

2017-08-01

The prebiotic effects of a cashew apple (Anacardium occidentale L.) agro-industrial byproduct powder (CAP) on different potentially probiotic Lactobacillus strains, namely Lactobacillus acidophilus LA-05, Lactobacillus casei L-26 and Lactobacillus paracasei L-10, were assessed using in vitro experimental models. Accordingly, the growth of the Lactobacillus strains when cultivated in a broth containing CAP (20 or 30 g L -1 ), glucose (20 g L -1 ) or fructooligosaccharides (FOS) (20 g L -1 ) was monitored over 48 h; the prebiotic activity scores of CAP were determined; and the changes in pH values, production of organic acids and consumption of sugars in growth media were verified. During the 48-h cultivation, similar viable cell counts were observed for the Lactobacillus strains grown in the different media tested. The CAP presented positive prebiotic activity scores toward all the tested Lactobacillus strains, indicating a desirable selective fermentable activity relative to enteric organisms. The cultivation of the Lactobacillus strains in broth containing glucose, FOS or CAP resulted in high viable cell counts, a decreased pH, the production of organic acids and the consumption of sugars over time, revealing intense bacterial metabolic activity. The CAP exerts potential prebiotic effects on different potentially probiotic Lactobacillus strains and should be an added-value ingredient for the food industry. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Organic Synthesis in Simulated Interstellar Ice Analogs

NASA Technical Reports Server (NTRS)

Dworkin, Jason P.; Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Deamer, David W.; Elsila, Jamie; Zare, Richard N.; DeVincenzi, Donald (Technical Monitor)

2001-01-01

Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. ID We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with LTV light from a hydrogen plasma lamp: The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.

Organic Synthesis in Simulated Interstellar Ice Analogs

NASA Technical Reports Server (NTRS)

Dworkin, Jason P.; Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Deamer, David W.; Elsila, Jamie; Zare, Richard N.

2001-01-01

Comets and carbonaceous micrometeorites may have been significant sources of organic compounds on the early Earth. Ices on grains in interstellar dense molecular clouds contain a variety of simple molecules as well as aromatic molecules of various sizes. While in these clouds the icy grains are processed by ultraviolet light and cosmic radiation which produces more complex organic molecules. We have run laboratory simulations to identify the types of molecules which could have been generated photolytically in pre-cometary ices. Experiments were conducted by forming various realistic interstellar mixed-molecular ices with and without polycyclic aromatic hydrocarbons (PAHs) at approx. 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The residue that remained after warming to room temperature was analyzed by HPLC, and by laser desorption mass spectrometry. The residue contains several classes of compounds which may be of prebiotic significance.

Parallel Prebiotic Origin of Canonical and Non-Canonical Purine Nucleosides

NASA Astrophysics Data System (ADS)

Becker, S.; Carell, T.

2017-07-01

RNA of all living organisms is highly modified. It is unclear if these non-canonical bases are ancestors of an early Earth or biological inventions. We investigated a prebiotic pathway that leads to canonical and non-canonical purine nucleosides.

A new route for the prebiotic synthesis of nucleobases and hydantoins in water/ice solutions involving the photochemistry of acetylene.

PubMed

Menor-Salván, César; Marín-Yaseli, Margarita R

2013-05-10

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. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comets: Cosmic connections with carbonaceous meteorites, interstellar molecules and the origin of life

NASA Technical Reports Server (NTRS)

Chang, S.

1979-01-01

The ions, radicals, and molecules observed in comets may be derived intact or by partial decomposition from parent compounds of the sort found either in the interstellar medium or in carbonaceous meteorites. The early loss of highly reducing primitive atmosphere and its replacement by a secondary atmosphere dominated by H2O, CO2, and N2, as depicted in current models of the earth's evolution, pose a dilemma for the origin of life: the synthesis of organic compounds necessary for life from components of the secondary atmosphere appears to be difficult, and plausible mechanisms have not been evaluated. Both comets and carbonaceous meteorites are implicated as sources for the earth's atmophilic and organogenic elements. A mass balance argument involving the estimated ratios of hydrogen to carbon in carbonaceous meteorites, comets, and the crust and upper mantle suggests that comets supplied the earth with a large fraction of its volatiles. The probability that comets contributed significantly to the earth's volatile inventory suggests a chemical evolutionary link between comets, prebiotic organic synthesis, and the origin of life.

Prebiotic significance of extraterrestrial ice photochemistry: detection of hydantoin in organic residues.

PubMed

de Marcellus, Pierre; Bertrand, Marylène; Nuevo, Michel; Westall, Frances; Le Sergeant d'Hendecourt, Louis

2011-11-01

The delivery of extraterrestrial organic materials to primitive Earth from meteorites or micrometeorites has long been postulated to be one of the origins of the prebiotic molecules involved in the subsequent apparition of life. Here, we report on experiments in which vacuum UV photo-irradiation of interstellar/circumstellar ice analogues containing H(2)O, CH(3)OH, and NH(3) led to the production of several molecules of prebiotic interest. These were recovered at room temperature in the semi-refractory, water-soluble residues after evaporation of the ice. In particular, we detected small quantities of hydantoin (2,4-imidazolidinedione), a species suspected to play an important role in the formation of poly- and oligopeptides. In addition, hydantoin is known to form under extraterrestrial, abiotic conditions, since it has been detected, along with various other derivatives, in the soluble part of organic matter of primitive carbonaceous meteorites. This result, together with other related experiments reported recently, points to the potential importance of the photochemistry of interstellar "dirty" ices in the formation of organics in Solar System materials. Such molecules could then have been delivered to the surface of primitive Earth, as well as other telluric (exo-) planets, to help trigger first prebiotic reactions with the capacity to lead to some form of primitive biomolecular activity.

Non-Enzymatic Synthesis of Duplex Nucleic Acid

NASA Astrophysics Data System (ADS)

Panchal, Z.; Oye, M.; Deamer, D.; Vercoutere, W.

2017-07-01

The earliest forms of life would likely have a protocellular form, with a membrane encapsulating some form of linear charged polymer that would have genetic properties; we simulate the plausible prebiotic conditions and use a nanopore for analysis.

Catalysis of peptide bond formation by histidyl-histidine in a fluctuating clay environment

NASA Technical Reports Server (NTRS)

White, D. H.; Erickson, J. C.

1980-01-01

The condensation of glycine to form oligoglycines during wet-dry fluctuations on clay surfaces was enhanced up to threefold or greater by small amounts of histidyl-histidine. In addition, higher relative yields of the longer oligomers were produced. Other specific dipeptides tested gave no enhancement, and imidazole, histidine, and N-acetylhistidine gave only slight enhancements. Histidyl-histidine apparently acts as a true catalyst (in the sense of repeatedly catalyzing the reaction), since up to 52 nmol of additional glycine were incorporated into oligoglycine for each nmol of catalyst added. This is the first known instance of a peptide or similar molecule demonstrating a catalytic turnover number greater than unity in a prebiotic oligomer synthesis reaction, and suggests that histidyl-histidine is a model for a primitive prebiotic proto-enzyme. Catalysis of peptide bond synthesis by a molecule which is itself a peptide implies that related systems may be capable of exhibiting autocatalytic growth.

Recent advances on prebiotic lactulose production.

PubMed

Sitanggang, Azis Boing; Drews, Anja; Kraume, Matthias

2016-09-01

Lactulose, a synthetic disaccharide, has received increasing interest due to its role as a prebiotic. The production of lactulose is important in the dairy industry, as it is regarded as a high value-added derivative of whey or lactose. The industrial production of lactulose is still mainly done by chemical isomerization. Due to concerns on the environmental and tedious separation processes, the enzymatic-based lactulose synthesis has been regarded as an interesting alternative. This work aims at comparing chemical and enzyme-catalyzed lactulose synthesis. With an emphasis on the latter one, this review discusses the influences of the critical operating conditions and the suited operation mode on the transgalactosylation of lactulose using microbial enzymes. As an update and supplement to other previous reviews, this work also summarizes the recent reports that highlighted the enzymatic isomerization of lactose using cellobiose 2-epimerase to produce lactulose at elevated yields.

Pre-biotic stage of life origin under non-photosynthetic conditions

NASA Technical Reports Server (NTRS)

Bartsev, S. I.; Mezhevikin, V. V.

2005-01-01

Spontaneous assembling of a simplest bacterial cell even if all necessary molecules are present in a solution seems to be extremely rare event and from the scientific standpoint has to be considered as impossible. Therefore, a predecessor of a living cell has to be very simple for providing its self-assembling and at the same time it should be able of progressive increase in complexity. Now phase-separated particles, first of all micelles, are put forward as possible predecessors of living cell. According to the offered working concept only phase-separated particles possessing autocatalytic properties can be considered as predecessors of living cells. The first stage of evolution of these phase-separated autocatalytic systems is the appearance of pre-biotic metabolism providing synthesis of amphiphiles for formation of capsules of these systems. This synthesis is maintained by the energy of a base reaction being a component of a planet-chemical cycle. Catalytic system providing functioning of pre-biotic metabolism is based on multivariate oligomeric autocatalyst, which reproduces itself from monomers, penetrating the particles from the outside. Since the autocatalyst realizes random polymerization then a collection of other oligomers possessing different catalytic functions is produced. In the paper the functioning of multivariate oligomeric autocatalyst in flow reactor is analyzed. c2005 Published by Elsevier Ltd on behalf of COSPAR.

Oligosaccharide biotechnology: an approach of prebiotic revolution on the industry.

PubMed

Mano, Mario Cezar Rodrigues; Neri-Numa, Iramaia Angélica; da Silva, Juliana Bueno; Paulino, Bruno Nicolau; Pessoa, Marina Gabriel; Pastore, Gláucia Maria

2018-01-01

Oligosaccharides are polymers with two to ten monosaccharide residues which have sweetener functions and sensory characteristics, in addition to exerting physiological effects on human health. The ones called nondigestible exhibit a prebiotic behavior being fermented by colonic microflora or stimulating the growth of beneficial bacteria, playing roles in the immune system, protecting against cancer, and preventing cardiovascular and metabolic issues. The global prebiotics market is expected to grow around 12.7% in the next 8 years, so manufacturers are developing new alternatives to obtain sustainable and efficient processes for application on a large scale. Most studied examples of biotechnological processes involve the development of new strategies for fructooligosaccharide, galactooligosaccharide, xylooligosaccharide, and mannanooligosaccharide synthesis. Among these, the use of whole cells in fermentation, synthesis of microbial enzymes (β-fructofuranosidases, β-galactosidases, xylanases, and β-mannanases), and enzymatic process development (permeabilization, immobilization, gene expression) can be highlighted, especially if the production costs are reduced by the use of agro-industrial residues or by-products such as molasses, milk whey, cotton stalks, corncobs, wheat straw, poplar wood, sugarcane bagasse, and copra meal. This review comprises recent studies to demonstrate the potential for biotechnological production of oligosaccharides, and also aspects that need more investigation for future applications in a large scale.

[Prebiotics: concept, properties and beneficial effects].

PubMed

Corzo, N; Alonso, J L; Azpiroz, F; Calvo, M A; Cirici, M; Leis, R; Lombó, F; Mateos-Aparicio, I; Plou, F J; Ruas-Madiedo, P; Rúperez, P; Redondo-Cuenca, A; Sanz, M L; Clemente, A

2015-02-07

Prebiotics are non-digestible food ingredients (oligosaccharides) that reach the colon and are used as substrate by microorganisms producing energy, metabolites and micronutrients used for the host; in addition they also stimulate the selective growth of certain beneficial species (mainly bifidobacteria and lactobacilli) in the intestinal microbiota. In this article, a multidisciplinary approach to understand the concept of prebiotic carbohydrates, their properties and beneficial effects in humans has been carried out. Definitions of prebiotics, reported by relevant international organizations and researchers, are described. A comprehensive description of accepted prebiotics having strong scientific evidence of their beneficial properties in humans (inulin-type fructans, FOS, GOS, lactulose and human milk oligosaccharides) is reported. Emerging prebiotics and those which are in the early stages of study have also included in this study. Taken into account that the chemical structure greatly influences carbohydrates prebiotic properties, the analytical techniques used for their analysis and characterization are discussed. In vitro and in vivo models used to evaluate the gastrointestinal digestion, absorption resistance and fermentability in the colon of prebiotics as well as major criteria to design robust intervention trials in humans are described. Finally, a comprehensive summary of the beneficial effects of prebiotics for health at systemic and intestinal levels is reported. The research effort on prebiotics has been intensive in last decades and has demonstrated that a multidisciplinary approach is necessary in order to claim their health benefits. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

On the Chemical Emergence of Phosphate-Based Biochemistry

NASA Astrophysics Data System (ADS)

Kee, Terence

Contemporary organisms use orthophosphate derivatives (PO43-) in their cell biochemistry,1 yet questions remain as to how Nature was able to accumulate, activate and exploit the or-thophosphate group from geological sources with both poorly solubility and low chemical activ-ity.2 Gulick argued3 a central role for reduced oxidation state phosphorus (P) oxyacids such as H-phosphonates (H2PO3-) and especially H-phosphinates (H2PO2-) in prebiotic chemistry on account of the greater water solubility of their metal salts and, with the presence of P-H bonds, a different reactivity profile to that expected of orthophosphate. The recent demonstration that hydrothermal corrosion of P-rich mineral phases such as schreibersite (Fe,Ni)3P within iron meteorites leads to production of various P-oxyacids including H-phosphonic (H3PO3)4 and H-phosphinic5 acids as well as orthophosphate has reignited interest in reduced oxida-tion state P chemistry in prebiotic environments. We are examining the prebiotic potential of reduced oxidation state P-chemistry through reactions with carbonyl substrates with rea-sonable prebiotic provenance including formaldehyde glycolaldehyde, both intimately involved in the formose reaction for sugar synthesis6 and pyruvic acid,7 a product of glycolysis and feed-stock for the citric acid cycle, a fundamental cellular metablic process whose heritage is considered an ancient one. In this contribution we present some of our latest results on the H-phosphinate-pyruvate system. References: [1] Lodish H et al. (2000) Molecular Cell Biology, 4th Ed., W. H. Freeman Co., New York. [2] Gulick A. (1955) Am. Sci., 43, 479. [3] Gulick A. (1957) Ann. N. Y. Acad. Sci. 69, 309. [4] Pasek M. A. (2008) Proc. Nat. Acad. Sci. USA, 105, 853. [5] Bryant D. E.and Kee T. P. (2006) Chem. Commun. 2344. [6] Weber A. L. (2000) Origins of Life and Evol. Biosph., 30, 33. [7] Cody G. D. et. al. (2000) Science 289, 1337.

Protoenzymes: the case of hyperbranched polyesters

NASA Astrophysics Data System (ADS)

Mamajanov, Irena; Cody, George D.

2017-11-01

Enzymes are biopolymeric complexes that catalyse biochemical reactions and shape metabolic pathways. Enzymes usually work with small molecule cofactors that actively participate in reaction mechanisms and complex, usually globular, polymeric structures capable of specific substrate binding, encapsulation and orientation. Moreover, the globular structures of enzymes possess cavities with modulated microenvironments, facilitating the progression of reaction(s). The globular structure is ensured by long folded protein or RNA strands. Synthesis of such elaborate complexes has proven difficult under prebiotically plausible conditions. We explore here that catalysis may have been performed by alternative polymeric structures, namely hyperbranched polymers. Hyperbranched polymers are relatively complex structures that can be synthesized under prebiotically plausible conditions; their globular structure is ensured by virtue of their architecture rather than folding. In this study, we probe the ability of tertiary amine-bearing hyperbranched polyesters to form hydrophobic pockets as a reaction-promoting medium for the Kemp elimination reaction. Our results show that polyesters formed upon reaction between glycerol, triethanolamine and organic acid containing hydrophobic groups, i.e. adipic and methylsuccinic acid, are capable of increasing the rate of Kemp elimination by a factor of up to 3 over monomeric triethanolamine. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Molecular microenvironments: Solvent interactions with nucleic acid bases and ions

NASA Technical Reports Server (NTRS)

Macelroy, R. D.; Pohorille, A.

1986-01-01

The possibility of reconstructing plausible sequences of events in prebiotic molecular evolution is limited by the lack of fossil remains. However, with hindsight, one goal of molecular evolution was obvious: the development of molecular systems that became constituents of living systems. By understanding the interactions among molecules that are likely to have been present in the prebiotic environment, and that could have served as components in protobiotic molecular systems, plausible evolutionary sequences can be suggested. When stable aggregations of molecules form, a net decrease in free energy is observed in the system. Such changes occur when solvent molecules interact among themselves, as well as when they interact with organic species. A significant decrease in free energy, in systems of solvent and organic molecules, is due to entropy changes in the solvent. Entropy-driven interactioins played a major role in the organization of prebiotic systems, and understanding the energetics of them is essential to understanding molecular evolution.

Emergence of photoautotrophic minimal protocell-like supramolecular assemblies, "Jeewanu" synthesied photo chemically in an irradiated sterilised aqueous mixture of some inorganic and organic substances.

PubMed

Gupta, Vinod Kumar

2014-12-01

Sunlight exposed sterilised aqueous mixture of ammonium molybdate, diammonium hydrogen phosphate, biological minerals and formaldehyde showed photochemical formation of self-sustaining biomimetic protocell-like supramolecular assemblies "Jeewanu" (Bahadur and Ranganayaki J Brit Interplanet Soc 23:813-829 1970). The structural and functional characteristics of Jeewanu suggests that in possible prebiotic atmosphere photosy nergistic collaboration of non-linear processes at mesoscopic level established autocatalytic pathways on mineral surfaces by selforganisation and self recognition and led to emergence of similar earliest energy transducing supramolecular assemblies which might have given rise to common universal ancestor on the earth or elsewhere.

Nucleobase and amino acid formation through impacts of meteorites on the early ocean

NASA Astrophysics Data System (ADS)

Furukawa, Yoshihiro; Nakazawa, Hiromoto; Sekine, Toshimori; Kobayashi, Takamichi; Kakegawa, Takeshi

2015-11-01

The emergence of life's building blocks on the prebiotic Earth was the first crucial step for the origins of life. Extraterrestrial delivery of intact amino acids and nucleobases is the prevailing hypothesis for their availability on prebiotic Earth because of the difficulties associated with the production of these organics from terrestrial carbon and nitrogen sources under plausible prebiotic conditions. However, the variety and amounts of these intact organics delivered by meteorites would have been limited. Previous shock-recovery experiments have demonstrated that meteorite impact reactions could have generated organics on the prebiotic Earth. Here, we report on the simultaneous formation of nucleobases (cytosine and uracil) found in DNA and/or RNA, various proteinogenic amino acids (glycine, alanine, serine, aspartic acid, glutamic acid, valine, leucine, isoleucine, and proline), non-proteinogenic amino acids, and aliphatic amines in experiments simulating reactions induced by extraterrestrial objects impacting on the early oceans. To the best of our knowledge, this is the first report of the formation of nucleobases from inorganic materials by shock conditions. In these experiments, bicarbonate was used as the carbon source. Bicarbonate, which is a common dissolved carbon species in CO2-rich atmospheric conditions, was presumably the most abundant carbon species in the early oceans and in post-impact plumes. Thus, the present results expand the possibility that impact-induced reactions generated various building blocks for life on prebiotic Earth in large quantities through the use of terrestrial carbon reservoirs.

Amino Acid Degradation after Meteoritic Impact Simulation

NASA Technical Reports Server (NTRS)

Bertrand, M.; Westall, F.; vanderGaast, S.; Vilas, F.; Hoerz, F.; Barnes, G.; Chabin, A.; Brack, A.

2008-01-01

Amino acids are among the most important prebiotic molecules as it is from these precursors that the building blocks of life were formed [1]. Although organic molecules were among the components of the planetesimals making up the terrestrial planets, large amounts of primitive organic precursor molecules are believed to be exogenous in origin and to have been imported to the Earth via micrometeorites, carbonaceous meteorites and comets, especially during the early stages of the formation of the Solar System [1,2]. Our study concerns the hypothesis that prebiotic organic matter, present on Earth, was synthesized in the interstellar environment, and then imported to Earth by meteorites or micrometeorites. We are particularly concerned with the formation and fate of amino acids. We have already shown that amino acid synthesis is possible inside cometary grains under interstellar environment conditions [3]. We are now interested in the effects of space conditions and meteoritic impact on these amino acids [4-6]. Most of the extraterrestrial organic molecules known today have been identified in carbonaceous chondrite meteorites [7]. One of the components of these meteorites is a clay with a composition close to that of saponite, used in our experiments. Two American teams have studied the effects of impact on various amino acids [8,9]. [8] investigated amino acids in saturated solution in water with pressure ranges between 5.1 and 21 GPa and temperature ranges between 412 and 870 K. [9] studied amino acids in solid form associated with and without minerals (Murchison and Allende meteorite extracts) and pressure ranges between 3 and 30 GPa. In these two experiments, the amino acids survived up to 15 GPa. At higher pressure, the quantity of preserved amino acids decreases quickly. Some secondary products such as dipeptides and diketopiperazins were identified in the [8] experiment.

β-galactosidase from Aspergillus lacticoffeatus: A promising biocatalyst for the synthesis of novel prebiotics.

PubMed

Cardoso, Beatriz B; Silvério, Sara C; Abrunhosa, Luís; Teixeira, José A; Rodrigues, Lígia R

2017-09-18

β-galactosidase (EC 3.2.1.23) are interesting enzymes able to catalyze lactose hydrolysis and transfer reactions to produce lactose-based prebiotics with potential application in the pharmaceutical and food industry. In this work, Aspergillus lacticoffeatus is described, for the first time, as an effective β-galactosidase producer. The extracellular enzyme production was evaluated in synthetic and alternative media containing cheese whey and corn steep liquor. Although β-galactosidase production occurred in all media (expect for the one composed solely by cheese whey), the highest enzymatic activity values (460U/mL) were obtained for the synthetic medium. Ochratoxin A production in synthetic medium was also evaluated and 9days of fermentation was identified as a suitable fermentation time to obtain a crude extract enzyme with mycotoxin concentration below the legal comparable value established for wine and grape juices (2ng/mL). The optimal pH and temperature for the crude extract enzyme was found in the range of 3.5-4.5 and 50-60°C, respectively. The β-galactosidase activity was reduced in the presence of Ba 2+ , Fe 2+ , Li + , K + and galactose, while additives (except for ascorbic acid) and detergents exhibited a positive effect on enzymatic activity. This enzyme was able to catalyze the synthesis of prebiotics, namely lactulose (2.5g/L) and a galacto-oligosaccharide (trisaccharide, 6.3g/L), either when whole cells or crude enzyme was used as biocatalyst. The lactulose production using fungal whole cells is herein reported for the first time. Additionally, A. lacticoffeatus was also found to produce an enzyme with fructosyltransferase activity and other prebiotics, namely fructo-oligosaccharide 1-kestose (2.4g/L). Copyright © 2017 Elsevier B.V. All rights reserved.

"Ames Research Center: Linking our Origins to our Future"

NASA Technical Reports Server (NTRS)

DesMarais, David J.

2005-01-01

Our research traces a path from interstellar materials to inhabited worlds and beyond. We examine how protoplanetary disks evolve and form terrestrial planets, the evolutionary paths of habitable planets, and how external factors (e.g., orbital eccentricity) and internal factors (atmospheric circulation) affect habitability. We trace, spectroscopically and chemically, the evolution of organic molecules from the interstellar medium onto habitable bodies. We examine how membranes might form under prebiotic planetary conditions. We evolve proteins capable of sustaining early metabolism, such as synthesis of biopolymers and transport of ions across membranes. We estimate the frequency of finding a functional prebiotic protein that formed spontaneously. We characterize the formation of diagnostic microbial biosignatures in rock-hosted ecosystems in ophiolite springs as an analog for subsurface life within our solar system, and photosynthetic microbial mats as biota that could be detected on extrasolar planets. We develop quantitative models that simulate energy relationships, biogeochemical cycling, trace gas exchange, and biodiversity. We examine the effects of climate variability on a vegetation-rich biosphere over intermediate time scales, using South American ecosystems as a model. We address natural transport of life beyond its planet of origin, such as on a meteorite, where survivors must withstand radiation, desiccation, and time in transit. We fly organisms and ecosystems in low Earth orbit to test their resistance to space. The Ames E&PO program disseminates these themes to national- and international-scale audiences through partnerships with the California Academy of Sciences, Yellow stone National Park, New York Hall of Science, and several K-14 educational organizations.

Synthesis and characterization of a potential prebiotic trisaccharide from cheese whey permeate and sucrose by Leuconostoc mesenteroides dextransucrase.

PubMed

Díez-Municio, Marina; Montilla, Antonia; Jimeno, M Luisa; Corzo, Nieves; Olano, Agustín; Moreno, F Javier

2012-02-29

The production of new bioactive oligosaccharides is currently garnering much attention for their potential use as functional ingredients. This work addresses the enzymatic synthesis and NMR structural characterization of 2-α-D-glucopyranosyl-lactose derived from sucrose:lactose and sucrose:cheese whey permeate mixtures by using a Leuconostoc mesenteroides B-512F dextransucrase. The effect of synthesis conditions, including concentration of substrates, molar ratio of donor/acceptor, enzyme concentration, reaction time, and temperature, on the formation of transfer products is evaluated. Results indicated that cheese whey permeate is a suitable material for the synthesis of 2-α-D-glucopyranosyl-lactose, giving rise to yields around 50% (in weight respect to the initial amount of lactose) under the optimum reaction conditions. According to its structure, this trisaccharide is an excellent candidate for a new prebiotic ingredient, due to the reported high resistance of α-(1→2) linkages to the digestive enzymes in humans and animals, as well as to its potential selective stimulation of beneficial bacteria in the large intestine mainly attributed to the two linked glucose units located at the reducing end that reflects the disaccharide kojibiose (2-α-D-glucopyranosyl-D-glucose). These findings could contribute to broadening the use of important agricultural raw materials, such as sucrose or cheese whey permeates, as renewable substrates for enzymatic synthesis of oligosaccharides of nutritional interest.

Isolation of Purines and Pyrimidines from the Murchison Meteorite Using Sublimation

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Bada, J. L.

2004-01-01

The origin of life on Earth, and possibly on other planets such as Mars, would have required the presence of liquid water and a continuous supply of prebiotic organic compounds. The exogenous delivery of organic matter by asteroids, comets, and carbonaceous meteorites could have contributed to the early Earth s prebiotic inventory by seeding the planet with biologically important organic compounds. A wide variety of prebiotic organic compounds have previously been detected in the Murchison CM type carbonaceous chondrite including amino acids, purines and pyrimidines. These compounds dominate terrestrial biochemistry and are integral components of proteins, DNA and RNA. Several purines including adenine, guanine, hypoxanthine, and xanthine, as well as the pyrimidine uracil, have previously been detected in water or formic acid extracts of Murchison using ion-exclusion chromatography and ultraviolet spectroscopy. However, even after purification of these extracts, the accurate identification and quantification of nucleobases is difficult due to interfering UV absorbing compounds. In order to reduce these effects, we have developed an extraction technique using sublimation to isolate purines and pyrimidines from other non-volatile organic compounds in Murchison acid extracts.

Study of Plasma Chemistry and Plasma Processing.

DTIC Science & Technology

1983-01-01

m, 20% 0,0-oxybisfpropionitrile] on Chrom W column in these reactions comes from their pertinence to prebiotic was used for cyanogen and gaseous...xerography, prebiotic chemistry, and chemistry in the ionosphere. L -5- Euipment for RF Reactions Virtually all of the work on organic plasmas has used RF

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ranjan, Sukrit; Sasselov, Dimitar D.; Wordsworth, Robin, E-mail: sranjan@cfa.harvard.edu

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UVmore » environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.« less

The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up

NASA Astrophysics Data System (ADS)

Ranjan, Sukrit; Wordsworth, Robin; Sasselov, Dimitar D.

2017-07-01

Potentially habitable planets orbiting M dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years because of a confluence of observational effects. Simultaneously, recent experimental and theoretical work suggests that UV light may have played a key role in the origin of life on Earth, especially the origin of RNA. Characterizing the UV environment on M-dwarf planets is important for understanding whether life as we know it could emerge on such worlds. In this work, we couple radiative transfer models to observed M-dwarf spectra to determine the UV environment on prebiotic Earth-analog planets orbiting M dwarfs. We calculate dose rates to quantify the impact of different host stars on prebiotically important photoprocesses. We find that M-dwarf planets have access to 100–1000 times less bioactive UV fluence than the young Earth. It is unclear whether UV-sensitive prebiotic chemistry that may have been important to abiogenesis, such as the only known prebiotically plausible pathways for pyrimidine ribonucleotide synthesis, could function on M-dwarf planets. This uncertainty affects objects like the recently discovered habitable-zone planets orbiting Proxima Centauri, TRAPPIST-1, and LHS 1140. Laboratory studies of the sensitivity of putative prebiotic pathways to irradiation level are required to resolve this uncertainty. If steady-state M-dwarf UV output is insufficient to power these pathways, transient elevated UV irradiation due to flares may suffice; laboratory studies can constrain this possibility as well.

Exercise and Prebiotics Produce Stress Resistance: Converging Impacts on Stress-Protective and Butyrate-Producing Gut Bacteria.

PubMed

Mika, A; Rumian, N; Loughridge, A B; Fleshner, M

2016-01-01

The gut microbial ecosystem can mediate the negative health impacts of stress on the host. Stressor-induced disruptions in microbial ecology (dysbiosis) can lead to maladaptive health effects, while certain probiotic organisms and their metabolites can protect against these negative impacts. Prebiotic diets and exercise are feasible and cost-effective strategies that can increase stress-protective bacteria and produce resistance against the detrimental behavioral and neurobiological impacts of stress. The goal of this review is to describe research demonstrating that both prebiotic diets and exercise produce adaptations in gut ecology and the brain that arm the organism against inescapable stress-induced learned helplessness. The results of this research support the novel hypothesis that some of the stress-protective effects of prebiotics and exercise are due to increases in stress-protective gut microbial species and their metabolites. In addition, new evidence also suggests that prebiotic diet or exercise interventions are most effective if given early in life (juvenile-adolescence) when both the gut microbial ecosystem and the brain are plastic. Based on our new understanding of the mechanistic convergence of these interventions, it is feasible to propose that in adults, both interventions delivered in combination may elevate their efficacy to promote a stress-resistant phenotype. © 2016 Elsevier Inc. All rights reserved.

Montmorillonite Clay-Catalyzed Synthesis of RNA Oligomers

NASA Astrophysics Data System (ADS)

Ferris, J. P.; Miyakawa, S.; Huang, W.; Joshi, P.

2005-12-01

It is proposed that catalysis had a central role in the origins of life. This will be illustrated using the montmorillonite clay-catalyzed synthesis of oligomers of RNA from activated monomers, (Ferris and Ertem, 1993) a possible step in the origin of the RNA world (Ferris, 2005). Structural analysis of oligomers formed in the reaction of the activated monomer of 5'-AMP with that of 5'-CMP demonstrated that the oligomers formed were not produced by random synthesis but rather the sequences observed were directed by the montmorillonite catalyst (Miyakawa and Ferris, 2003). RNA oligomers containing up to 40 mers have been synthesized in reactions performed in water at 25 oC in the presence of montmorillonite (Huang and Ferris, 2003). Analysis of the structure elements in these oligomers from the 7 to 39 mers showed that they did not vary. Reaction of D, L-mixtures of the activated monomers of A and U resulted in the formation of greater amounts of the homochiral amounts of dimers and trimers of A than would be expected if there was no selectivity in the reaction. A limited number of the dimers and trimers of U were also formed but here the selectivity was for the formation of an excess of heterochiral products (Joshi et al., 2000). A postulate that explains why homochiral trimers of U are not formed and the significance of catalysis in prebiotic synthesis will be discussed. Ferris, J.P. (2005) Origins of life, molecular basis of. In R.A. Meyers, Ed. Encyclopedia of Molecular Cell Biology and Molecular Medicine, 10. Wiley-VCH Verlag, Weinheim, Germany. Ferris, J.P., and Ertem, G. (1993) Montmorillonite catalysis of RNA oligomer formation in aqueous solution. A model for the prebiotic formation of RNA. J. Am. Chem. Soc., 115, 12270-12275. Huang, W., and Ferris, J.P. (2003) Synthesis of 35-40 mers of RNA oligomers from unblocked monomers. A simple approach to the RNA world. Chem. Commun., 1458-1459. Joshi, P.C., Pitsch, S., and Ferris, J.P. (2000) Homochiral selection in the montmorillonite-catalyzed and uncatalyzed prebiotic synthesis of RNA. Chem. Commun., 2497-2498. Miyakawa, S., and Ferris, J.P. (2003) Sequence- and Regioselectivity in the montmorillonite-catalyzed synthesis of RNA. J. Am. Chem. Soc., 125, 8202-8208.

Prebiotic Polymer Synthesis and the Origin of Glycolytic Metabolism

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1998-01-01

Our research resulted in several discoveries which contributed to understanding the origin and operation of life. (1) Most importantly, we discovered a new pathway of prebiotic amino acid synthesis in which formaldehyde and glycolaldehyde (formose reaction substrates) react with ammonia to give alanine and homoserine in the presence of thiol catalysts. The thiol-dependent synthesis of amino acids undoubtedly occurs via amino acid thioester intermediates capable of forming peptides. This 'one-pot' reaction system operates under mild aqueous conditions, and like modern amino acid biosynthesis, uses sugar intermediates which are converted to amino acids by energy-yielding redox disproportionation. Preliminary evidence suggests that this type of process can be "evolved" by a serial transfer methods that lead to enrichment of autocatalytic molecules. (2) We established that prebiotic peptide polymers can be made by condensation of amino acid thioesters (homocysteine thiolactone and S-(N-beta-orotidyl- diaminopropionic acid) ethanethiol), and that prebiotic polydisulfide polymers can be generated by oxidation of dithiols with iron(III) in minerals. (3) In our analysis of metabolism we discovered the primary energy source of biosynthesis -- chemical energy made available by the redox disproportionation of substrate carbon groups. We concluded that the energy and reactivity of sugars make them the optimal substrate for the origin and operation of terrestrial (or extraterrestrial) life. (4) Since it is likely that the use of optimal sugar substrates in biosynthesis sets the average oxidation number of functional biocarbon throughout the Universe near 0.0 (the reduction level of formaldehyde), we proposed that a line(s) in the microwave spectrum of formaldehyde could be rationally selected as a frequency for interstellar communication that symbolizes life. (5) Finally, in preparation for the analysis of Martian meteorite samples, we upgraded our HPLC system to one femtomole sensitivity, and developed a new electrophoretic method of sample preparation for HPLC analysis of the meteoritic amino acids. In a sample of the KT boundary layer from Sussex Wyoming, we found about 300 picomoles per gram of meteoritic alpha-aminoisobutyric acid per gram of KT layer.

Prebiotic NH3 Formation: Insights from Simulations.

PubMed

Stirling, András; Rozgonyi, Tamás; Krack, Matthias; Bernasconi, Marco

2016-02-15

Simulations of prebiotic NH₃ synthesis from NO₃⁻ and NO₂⁻ on pyrite surfaces under hydrothermal conditions are reported. Ab initio metadynamics calculations have successfully explored the full reaction path which explains earlier experimental observations. We have found that the reaction mechanism can be constructed from stepwise single atom transfers which are compatible with the expected reaction time scales. The roles of the hot-pressurized water and of the pyrite surfaces have been addressed. The mechanistic picture that emerged from the simulations strengthens the theory of chemoautotrophic origin of life by providing plausible reaction pathways for the formation of ammonia within the iron-sulfur-world scenario.

Computer simulation and experimental self-assembly of irradiated glycine amino acid under magnetic fields: Its possible significance in prebiotic chemistry.

PubMed

Heredia, Alejandro; Colín-García, María; Puig, Teresa Pi I; Alba-Aldave, Leticia; Meléndez, Adriana; Cruz-Castañeda, Jorge A; Basiuk, Vladimir A; Ramos-Bernal, Sergio; Mendoza, Alicia Negrón

2017-12-01

Ionizing radiation may have played a relevant role in chemical reactions for prebiotic biomolecule formation on ancient Earth. Environmental conditions such as the presence of water and magnetic fields were possibly relevant in the formation of organic compounds such as amino acids. ATR-FTIR, Raman, EPR and X-ray spectroscopies provide valuable information about molecular organization of different glycine polymorphs under static magnetic fields. γ-glycine polymorph formation increases in irradiated samples interacting with static magnetic fields. The increase in γ-glycine polymorph agrees with the computer simulations. The AM1 semi-empirical simulations show a change in the catalyst behavior and dipole moment values in α and γ-glycine interaction with the static magnetic field. The simulated crystal lattice energy in α-glycine is also affected by the free radicals under the magnetic field, which decreases its stability. Therefore, solid α and γ-glycine containing free radicals under static magnetic fields might have affected the prebiotic scenario on ancient Earth by causing the oligomerization of glycine in prebiotic reactions. Copyright © 2017 Elsevier B.V. All rights reserved.

Origin and Evolution of Prebiotic Organic Matter as Inferred from the Tagish Lake Meteorite

NASA Technical Reports Server (NTRS)

Herd, Christopher D.; Blinova, Alexandra; Simkus, Danielle N.; Huang, Yongsong; Tarozo, Rafael; Alexander, Conel M.; Gyngard, Frank; Nittler, Larry R.; Cody, George D.; Fogel, Marilyn L.;

Mineral-organic interfacial processes: potential roles in the origins of life.

PubMed

Cleaves, H James; Michalkova Scott, Andrea; Hill, Frances C; Leszczynski, Jerzy; Sahai, Nita; Hazen, Robert

2012-08-21

Life is believed to have originated on Earth ∼4.4-3.5 Ga ago, via processes in which organic compounds supplied by the environment self-organized, in some geochemical environmental niches, into systems capable of replication with hereditary mutation. This process is generally supposed to have occurred in an aqueous environment and, likely, in the presence of minerals. Mineral surfaces present rich opportunities for heterogeneous catalysis and concentration which may have significantly altered and directed the process of prebiotic organic complexification leading to life. We review here general concepts in prebiotic mineral-organic interfacial processes, as well as recent advances in the study of mineral surface-organic interactions of potential relevance to understanding the origin of life.

Synthesis and Development of Porous Polymeric Column Packing and Microchip Detectors for GC Analysis of Extraterrestrial Atmospheres

NASA Technical Reports Server (NTRS)

Shen, Thomas C.

1999-01-01

This report summarizes the last nine years research accomplishments under Cooperative Agreement NCC2-650 between NASA, Ames Research Center and SETI Institute. Four Major research tasks are conducted: 1. Gas chromatography column development. 2. Pyrosensor development. 3. Micro-machining gas chromatography instrument development. 4. Amino acid analysis and high molecular weight polyamino acid synthesis under prebiotic conditions. The following describes these results.

Cometary material and the origins of life on earth

NASA Technical Reports Server (NTRS)

Lazcano-Araujo, A.; Oro, J.

1981-01-01

The role of cometary material in determining the environmental conditions of the prebiotic earth is reviewed. The organic synthesis pathways that occur in dense interstellar clouds and in comets are examined, and complex organic molecules believed to exist (amino acids, carboxylic acids, purines, pyrimidines and hydrocarbons) based on spectral detections of degradation products are noted. Estimates of the amount of terrestrial volatiles of cometary origin that may have been acquired in collisions during the early history of the earth are considered, and shown to dominate any estimated contributions to terrestrial carbon from other extraterrestrial sources. Current evidence that the origin and early evolution of life began about four billion years ago is discussed in relation to the cometary bombardment processes occurring at the time and the resultant shock waves, reducing atmospheres and reactive chemical species. It is thus concluded that comets contributed significantly to the processes of chemical evolution necessary for the emergence of life on earth.

Prebiotic Synthesis of Autocatalytic Products From Formaldehyde-Derived Sugars as the Carbon and Energy Source

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

2003-01-01

Our research objective is to understand and model the chemical processes on the primitive Earth that generated the first autocatalytic molecules and microstructures involved in the origin of life. Our approach involves: (a) investigation of a model origin-of-life process named the Sugar Model that is based on the reaction of formaldehyde- derived sugars (trioses and tetroses) with ammonia, and (b) elucidation of the constraints imposed on the chemistry of the origin of life by the fixed energies and rates of C,H,O-organic reactions under mild aqueous conditions. Recently, we demonstrated that under mild aqueous conditions the Sugar Model process yields autocatalytic products, and generates organic micropherules (2-20 micron dia.) that exhibit budding, size uniformity, and chain formation. We also discovered that the sugar substrates of the Sugar Model are capable of reducing nitrite to ammonia under mild aqueous conditions. In addition studies done in collaboration with Sandra Pizzarrello (Arizona State University) revealed that chiral amino acids (including meteoritic isovaline) catalyze both the synthesis and specific handedness of chiral sugars. Our systematic survey of the energies and rates of reactions of C,H,O-organic substrates under mild aqueous conditions revealed several general principles (rules) that govern the direction and rate of organic reactions. These reactivity principles constrain the structure of chemical pathways used in the origin of life, and in modern and primitive metabolism.

A viscous solvent enables information transfer from gene-length nucleic acids in a model prebiotic replication cycle

NASA Astrophysics Data System (ADS)

He, Christine; Gállego, Isaac; Laughlin, Brandon; Grover, Martha A.; Hud, Nicholas V.

2017-04-01

Many hypotheses concerning the nature of early life assume that genetic information was once transferred through the template-directed synthesis of RNA, before the emergence of coded enzymes. However, attempts to demonstrate enzyme-free, template-directed synthesis of nucleic acids have been limited by 'strand inhibition', whereby transferring information from a template strand in the presence of its complementary strand is inhibited by the stability of the template duplex. Here, we use solvent viscosity to circumvent strand inhibition, demonstrating information transfer from a gene-length template (>300 nt) within a longer (545 bp or 3 kb) duplex. These results suggest that viscous environments on the prebiotic Earth, generated periodically by water evaporation, could have facilitated nucleic acid replication—particularly of long, structured sequences such as ribozymes. Our approach works with DNA and RNA, suggesting that viscosity-mediated replication is possible for a range of genetic polymers, perhaps even for informational polymers that may have preceded RNA.

Simulation of Prebiotic Processing by Comet and Meteoroid Impact: Implications for Life on Early Earth and Other Planets

NASA Technical Reports Server (NTRS)

Dateo, Christopher E.

2003-01-01

We develop a reacting flow model to simulate the shock induced chemistry of comets and meteoroids entering planetary atmospheres. Various atmospheric compositions comprising of simpler molecules (i.e., CH4, CO2, H2O, etc.) are investigated to determine the production efficiency of more complex prebiotic molecules as a function of composition, pressure, and entry velocity. The possible role of comets and meteoroids in creating the inventory of prebiotic material necessary for life on Early Earth is considered. Comets and meteoroids can also introduce new materials from the Interstellar Medium (ISM) to planetary atmospheres. The ablation of water from comets, introducing the element oxygen into Titan's atmosphere will also be considered and its implications for the formation of organic and prebiotic material.

Chemical Evolution and the Origin of Life: Bibliography 1975

NASA Technical Reports Server (NTRS)

West, Martha W. (Compiler); Koch, Rowena A. (Compiler); Chang, Sherwood (Compiler)

1977-01-01

This bibliography is the sixth annual supplement to the comprehensive bibliography on the same subject which was published in Space Life Sci.We would like to draw attention to a recently published cumulative bibliography on this same subject: Biochemical Origin of Life: Chemistry and Life. Soil and Water and Its Relationship to Origin of Life. MR - Studies of Prebiotic Polypeptides. Energy, Matter, and Life. Prospects for the Future Orientation of Scientific Research. Photochemical Formation of Self Sustaining Coacervates. Photochemical Formation of Self-Sustaining Coacervates. Comparative Study of Abiogenesis of Cysteine and Other Amino Acids Catalyzed by Various Metal Ions. Protein Structure and the Molecular Evolution of Biological Energy Conversion. Origin of Life. Clues from Relations Between Chemical Compositions of Living Organisms and Natural Environments. Shock Synthesis of Amino Acids II.', Origins of Life 6(1-2). Dynamics of the Chemical Evolution of Earth's Primitive Atmosphere. The Mechanisms of Amino Acids Synthesis by High Temperature Shock-Waves. Theory of Chemical Evolution. Physical Foundations of Probability of Biogenesis.

Prebiotics for the prevention of allergies: A systematic review and meta-analysis of randomized controlled trials.

PubMed

Cuello-Garcia, C; Fiocchi, A; Pawankar, R; Yepes-Nuñez, J J; Morgano, G P; Zhang, Y; Agarwal, A; Gandhi, S; Terracciano, L; Schünemann, H J; Brozek, J L

2017-11-01

Prevalence of allergic diseases in infants is approximately 10% reaching 20 to 30% in those with an allergic first-degree relative. Prebiotics are selectively fermented food ingredients that allow specific changes in composition/activity of the gastrointestinal microflora. They modulate immune responses, and their supplementation has been proposed as an intervention to prevent allergies. To assess in pregnant women, breastfeeding mothers, and infants (populations) the effect of supplementing prebiotics (intervention) versus no prebiotics (comparison) on the development of allergic diseases and to inform the World Allergy Organization guidelines. We performed a systematic review of studies assessing the effects of prebiotic supplementation with an intention to prevent the development of allergies. Of 446 unique records published until November 2016 in Cochrane, MEDLINE, and EMBASE, 22 studies fulfilled a priori specified criteria. We did not find any studies of prebiotics given to pregnant women or breastfeeding mothers. Prebiotic supplementation in infants, compared to placebo, had the following effects: risk of developing eczema (RR: 0.68, 95% CI: 0.40 to 1.15), wheezing/asthma (RR, 0.37; 95% CI: 0.17 to 0.80), and food allergy (RR: 0.28, 95% CI: 0.08 to 1.00). There was no evidence of an increased risk of any adverse effects (RR: 1.01, 95% CI: 0.92 to 1.10). Prebiotic supplementation had little influence growth rate (MD: 0.92 g per day faster with prebiotics, 95% CI: 0 to 1.84) and the final infant weight (MD: 0.10 kg higher with prebiotics, 95% CI: -0.09 to 0.29). The certainty of these estimates is very low due to risk of bias and imprecision of the results. Currently available evidence on prebiotic supplementation to reduce the risk of developing allergies is very uncertain. © 2017 John Wiley & Sons Ltd.

Asphalt, water, and the prebiotic synthesis of ribose, ribonucleosides, and RNA.

PubMed

Benner, Steven A; Kim, Hyo-Joong; Carrigan, Matthew A

2012-12-18

RNA has been called a "prebiotic chemist's nightmare" because of its combination of large size, carbohydrate building blocks, bonds that are thermodynamically unstable in water, and overall intrinsic instability. However, a discontinuous synthesis model is well-supported by experimental work that might produce RNA from atmospheric CO(2), H(2)O, and N(2). For example, electrical discharge in such atmospheres gives formaldehyde (HCHO) in large amounts and glycolaldehyde (HOCH(2)CHO) in small amounts. When rained into alkaline aquifers generated by serpentinizing rocks, these substances were undoubtedly converted to carbohydrates including ribose. Likewise, atmospherically generated HCN was undoubtedly converted in these aquifers to formamide and ammonium formate, precursors for RNA nucleobases. Finally, high reduction potentials maintained by mantle-derived rocks and minerals would allow phosphite to be present in equilibrium with phosphate, mobilizing otherwise insoluble phosphorus for the prebiotic synthesis of phosphite and phosphate esters after oxidation. So why does the community not view this discontinuous synthesis model as compelling evidence for the RNA-first hypothesis for the origin of life? In part, the model is deficient because no experiments have joined together those steps without human intervention. Further, many steps in the model have problems. Some are successful only if reactive compounds are presented in a specific order in large amounts. Failing controlled addition, the result produces complex mixtures that are inauspicious precursors for biology, a situation described as the "asphalt problem". Many bonds in RNA are thermodynamically unstable with respect to hydrolysis in water, creating a "water problem". Finally, some bonds in RNA appear to be "impossible" to form under any conditions considered plausible for early Earth. To get a community-acceptable "RNA first" model for the origin of life, the discontinuous synthesis model must be developed. In particular, the model must be refined so that it yields oligomeric RNA from CO(2), H(2)O, and N(2) without human intervention. This Account describes our efforts in this direction. Our hypothesis centers on a geological model that synthesizes RNA in a prebiotic intermountain dry valley (not in a marine environment). This valley receives high pH run-off from a watershed rich in serpentinizing olivines and eroding borate minerals. The runoff contains borate-stabilized carbohydrates, formamide, and ammonium formate. As atmospheric CO(2) dissolves in the subaerial aquifer, the pH of the aquifer is lowered. In the desert valley, evaporation of water, a solvent with a nucleophilic "background reactivity", leaves behind formamide, a solvent with an electrophilic "background reactivity". As a result, nucleobases, formylated nucleobases, and formylated carbohydrates, including formylated ribose, can form. Well-known chemistry transforms these structures into nucleosides, nucleotides, and partially formylated oligomeric RNA.

Silicate-Promoted Phosphorylation of Glycerol in Non-Aqueous Solvents: A Prebiotically Plausible Route to Organophosphates

PubMed Central

Gull, Maheen; Cafferty, Brian J.; Hud, Nicholas V.; Pasek, Matthew A.

2017-01-01

Phosphorylation reactions of glycerol were studied using different inorganic phosphates such as sodium phosphate, trimetaphosphate (a condensed phosphate), and struvite. The reactions were carried out in two non-aqueous solvents: formamide and a eutectic solvent consisting of choline-chloride and glycerol in a ratio of 1:2.5. The glycerol reacted in formamide and in the eutectic solvent with phosphate to yield its phosphorylated derivatives in the presence of silicates such as quartz sand and kaolinite clay. The reactions were carried out by heating glycerol with a phosphate source at 85 °C for one week and were analyzed by 31P-nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The yield of the phosphorylated glycerol was improved by the presence of silicates, and reached 90% in some experiments. Our findings further support the proposal that non-aqueous solvents are advantageous for the prebiotic synthesis of biomolecules, and suggest that silicates may have aided in the formation of organophosphates on the prebiotic earth. PMID:28661422

Synthesis of goethite in solutions of artificial seawater and amino acids: a prebiotic chemistry study

NASA Astrophysics Data System (ADS)

Carneiro, Cristine E. A.; Ivashita, Flávio F.; de Souza, Ivan Granemann; de Souza, Cláudio M. D.; Paesano, Andrea; da Costa, Antonio C. S.; di Mauro, Eduardo; de Santana, Henrique; Zaia, Cássia T. B. V.; Zaia, Dimas A. M.

2013-04-01

This study investigated the synthesis of goethite under conditions resembling those of the prebiotic Earth. The artificial seawater used contains all the major elements as well as amino acids (α-Ala, β-Ala, Gly, Cys, AIB) that could be found on the prebiotic Earth. The spectroscopic methods (FT-IR, EPR, Raman), scanning electron microscopy (SEM) and X-ray diffraction showed that in any condition Gly and Cys favoured the formation of goethite, artificial seawater plus β-Ala and distilled water plus AIB favoured the formation of hematite and for the other synthesis a mixture of goethite and hematite were obtained. Thus in general no protein amino acids (β-Ala, AIB) favoured the formation of hematite. As shown by surface enhanced Raman spectroscopy (SERS) spectra the interaction between Cys and Fe3+ of goethite is very complex, involving decomposition of Cys producing sulphur, as well as interaction of carboxylic group with Fe3+. SERS spectra also showed that amino/CN and C-CH3 groups of α-Ala are interacting with Fe3+ of goethite. For the other samples the shifting of several bands was observed. However, it was not possible to say which amino acid groups are interacting with Fe3+. The pH at point of zero charge of goethites increased with artificial seawater and decreased with amino acids. SEM images showed when only goethite was synthesized the images of the samples were acicular and when only hematite was synthesized the images of the samples were spherical. SEM images for the synthesis of goethite with Cys were spherical crystal aggregates with radiating acicular crystals. The highest resonance line intensities were obtained for the samples where only hematite was obtained. Electron paramagnetic resonance (EPR) and Mössbauer spectra showed for the synthesis of goethite with artificial seawater an isomorphic substitution of iron by seawater cations. Mössbauer spectra also showed that for the synthesis goethite in distilled water plus Gly only goethite was synthesized and in artificial seawater plus Cys a doublet due to interaction of iron with artificial seawater/Cys was observed. It should be pointed out that EPR spectroscopy did not show the interaction of iron with artificial seawater/Cys.

Taming Prebiotic Chemistry: The Role of Heterogeneous and Interfacial Catalysis in the Emergence of a Prebiotic Catalytic/Information Polymer System

PubMed Central

Monnard, Pierre-Alain

2016-01-01

Cellular life is based on interacting polymer networks that serve as catalysts, genetic information and structural molecules. The complexity of the DNA, RNA and protein biochemistry suggests that it must have been preceded by simpler systems. The RNA world hypothesis proposes RNA as the prime candidate for such a primal system. Even though this proposition has gained currency, its investigations have highlighted several challenges with respect to bulk aqueous media: (1) the synthesis of RNA monomers is difficult; (2) efficient pathways for monomer polymerization into functional RNAs and their subsequent, sequence-specific replication remain elusive; and (3) the evolution of the RNA function towards cellular metabolism in isolation is questionable in view of the chemical mixtures expected on the early Earth. This review will address the question of the possible roles of heterogeneous media and catalysis as drivers for the emergence of RNA-based polymer networks. We will show that this approach to non-enzymatic polymerizations of RNA from monomers and RNA evolution cannot only solve some issues encountered during reactions in bulk aqueous solutions, but may also explain the co-emergence of the various polymers indispensable for life in complex mixtures and their organization into primitive networks. PMID:27827919

The first living systems: a bioenergetic perspective

NASA Technical Reports Server (NTRS)

Deamer, D. W.; Bada, J. L. (Principal Investigator)

1997-01-01

The first systems of molecules having the properties of the living state presumably self-assembled from a mixture of organic compounds available on the prebiotic Earth. To carry out the polymer synthesis characteristic of all forms of life, such systems would require one or more sources of energy to activate monomers to be incorporated into polymers. Possible sources of energy for this process include heat, light energy, chemical energy, and ionic potentials across membranes. These energy sources are explored here, with a particular focus on mechanisms by which self-assembled molecular aggregates could capture the energy and use it to form chemical bonds in polymers. Based on available evidence, a reasonable conjecture is that membranous vesicles were present on the prebiotic Earth and that systems of replicating and catalytic macromolecules could become encapsulated in the vesicles. In the laboratory, this can be modeled by encapsulated polymerases prepared as liposomes. By an appropriate choice of lipids, the permeability properties of the liposomes can be adjusted so that ionic substrates permeate at a sufficient rate to provide a source of monomers for the enzymes, with the result that nucleic acids accumulate in the vesicles. Despite this progress, there is still no clear mechanism by which the free energy of light, ion gradients, or redox potential can be coupled to polymer bond formation in a protocellular structure.

Experimentally Tracing the Key Steps in the Origin of Life: The Aromatic World

NASA Astrophysics Data System (ADS)

Ehrenfreund, Pascale; Rasmussen, Steen; Cleaves, James; Chen, Liaohai

2006-06-01

Life is generally believed to emerge on Earth, to be at least functionally similar to life as we know it today, and to be much simpler than modern life. Although minimal life is notoriously difficult to define, a molecular system can be considered alive if it turns resources into building blocks, replicates, and evolves. Primitive life may have consisted of a compartmentalized genetic system coupled with an energy-harvesting mechanism. How prebiotic building blocks self-assemble and transform themselves into a minimal living system can be broken into two questions: (1) How can prebiotic building blocks form containers, metabolic networks, and informational polymers? (2) How can these three components cooperatively organize to form a protocell that satisfies the minimal requirements for a living system? The functional integration of these components is a difficult puzzle that requires cooperation among all the aspects of protocell assembly: starting material, reaction mechanisms, thermodynamics, and the integration of the inheritance, metabolism, and container functionalities. Protocells may have been self-assembled from components different from those used in modern biochemistry. We propose that assemblies based on aromatic hydrocarbons may have been the most abundant flexible and stable organic materials on the primitive Earth and discuss their possible integration into a minimal life form. In this paper we attempt to combine current knowledge of the composition of prebiotic organic material of extraterrestrial and terrestrial origin, and put these in the context of possible prebiotic scenarios. We also describe laboratory experiments that might help clarify the transition from nonliving to living matter using aromatic material. This paper presents an interdisciplinary approach to interface state of the art knowledge in astrochemistry, prebiotic chemistry, and artificial life research.

Reduction of nitrogen compounds in oceanic basement and its implications for HCN formation and abiotic organic synthesis

PubMed Central

2009-01-01

Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur. PMID:19849830

Reduction of nitrogen compounds in oceanic basement and its implications for HCN formation and abiotic organic synthesis.

PubMed

Holm, Nils G; Neubeck, Anna

2009-10-22

Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.

Prebiotic synthesis and reactions of nucleosides and nucleotides

NASA Astrophysics Data System (ADS)

Ferris, J. P.; Yanagawa, H.; Hagan, W. J.

Diiminosuccinonitrile (DISN) has been investigated as a potential prebiotic phosphorylating agent. It is formed readily by the oxidation of diaminomaleonitrile (DAMN), a tetramer of HCN, DISN effects the cyclization of 3'-adenosine monophosphate to adenosine 2',3'-cyclic phosphate in up to 40% yield. The DISN-mediated phosphorylation of uridine to uridine monophosphate does not proceed efficiently in aqueous solution. The reaction of DISN and BrCN with uridine-5'-phosphate and uridine results in the formation of 2,2'-anhydronucleotides and 2,2'-anhydronucleosides respectively, and other reaction products resulting from an initial reaction at the 2'- and 3'-hydroxyl groups. The clay mineral catalysis of the cyclization of adenosine-3'-phosphate was investigated using homoionic montmorillonites.

From organic chemistry in small bodies of the solar system to low temperature chemistry in the universe. Preface.

PubMed

Levasseur-Regourd, A C; Raulin, F

1995-01-01

A COSPAR two days Symposium has been dedicated to "Prebiotic chemistry in Space" at the COSPAR Plenary Meeting, (Hamburg, Germany, July 1994). This Symposium was jointly organized by Commissions B (Space studies of the Earth-Moon system, planets and small bodies of the solar system) and F (Life sciences as related to space). Its goal was to review, from an interdisciplinary approach, our knowledge on organic and prebiotic chemistry in small bodies of the Solar System, and on low temperature chemistry and exobiology. The Symposium was sponsored by COSPAR and the IAU (session 1), ESA, NASA, and ISSOL (session 2).

Was Ferrocyanide a Prebiotic Reagent?

NASA Technical Reports Server (NTRS)

Keefe, Anthony D.; Miller, Stanley L.

1996-01-01

Hydrogen cyanide is the starting material for a diverse array of prebiotic syntheses, including those of amino acids and purines. Hydrogen cyanide also reacts with ferrous ions to give ferrocyanide, and so it is possible that ferrocyanide was common in the early ocean. This can only be true if the hydrogen cyanide concentration was high enough and the rate of reaction of cyanide with ferrous ions was fast enough. We show experimentally that the rate of formation of ferrocyanide is rapid even at low concentrations of hydrogen cyanide in the pH range 6-8, and therefore an equilibrium calculation is valid. The equilibrium concentrations of ferrocyanide are calculated as a function of hydrogen cyanide concentration, pH and temperature. The steady state concentration of hydrogen cyanide depends on the rate of synthesis by electric discharges and ultraviolet light and the rate of hydrolysis, which depends on pH and temperature. Our conclusions show that ferrocyanide was a major species in the prebiotic ocean only at the highest production rates of hydrogen cyanide in a strongly reducing atmosphere and at temperatures of 0 C or less, although small amounts would have been present at lower hydrogen cyanide production rates. The prebiotic application of ferrocyanide as a source of hydrated electrons, as a photochemical replication process, and in semi-permeable membranes is discussed.

Energetics and kinetics of the prebiotic synthesis of simple organic acids and amino acids with the FeS-H2S/FeS2 redox couple as reductant

NASA Technical Reports Server (NTRS)

Schoonen, M. A.; Xu, Y.; Bebie, J.

1999-01-01

The thermodynamics of the FeS-H2S/FeS2 redox couple and a select number of reactions critical to the synthesis of simple carboxylic acids and amino acids have been evaluated as a function of temperature. This thermodynamic evaluation shows that the reducing power of the FeS-H2S/FeS2 redox couple decreases drastically with temperature. By contrast the equilibria describing the reduction of CO2 and the formation of simple carboxylic acids and amino acids require an increasingly higher reducing power with temperature. Given these two opposite trends, the thermodynamic driving force for CO2 reduction and amino acid formation with the FeS-H2S/FeS2 redox couple as reductant diminishes with increasing temperature. An evaluation of the mechanism of CO2 reduction by the FeS-H2S/FeS2 couple suggests that the electron transfer from pyrrhotite to CO2 is hindered by a high activation energy, even though the overall reaction is thermodynamically favorable. By comparison the electron transfer from pyrrhotite to either CS2, CO, or HCOOH are far more facile. This theoretical analysis explains the results of experimental work by Keefe et al. (1995), Heinen and Lauwers (1996) and Huber and Wachtershauser (1997). The implication is that a reaction sequence involving the reduction of CO2 with the FeS-H2S/FeS2 couple as reductant is unlikely to initiate a proposed prebiotic carbon fixation cycle (Wachtershauser, 1988b; 1990b, 1990a, 1992, 1993).

Prebiotic significance of the Maillard reaction

NASA Astrophysics Data System (ADS)

Kolb, Vera M.; Bajagic, Milica; Zhu, William; Cody, George D.

2005-09-01

The Maillard reaction was studied from a prebiotic point of view. We have shown that the Maillard reaction between ribose and common amino acids occurs readily in the solid state at 65°C. The C-13 NMR spectra of the solid insoluble Maillard products of ribose and serine, or alanine or isoleucine were compared to the spectrum of the insoluble organic carbon on Murchison.

Heterogeneity to Homogeneity: Synthesis, Base Pairing, and Ligation Studies of 4',3'-XyluloNA/RNA and TNA/RNA Chimeric Sequences

NASA Astrophysics Data System (ADS)

Bhowmik, S.; Stoop, M.; Krishnamurthy, R.

2017-07-01

Based on the reality of "prebiotic clutter," we herein present an alternate model for pre-RNA to RNA transition, which starts, not with homogeneous-backbone system, but rather with mixtures of heterogeneous-backbone of chimeric "pre-RNA/RNA."

Prebiotic synthesis in atmospheres containing CH4, CO, and CO2. I - Amino acids

NASA Technical Reports Server (NTRS)

Schlesinger, G.; Miller, S. L.

1983-01-01

The prebiotic synthesis of amino acids, HCN, H2CO, and NH3 using a spark discharge on various simulated primitive earth atmospheres at 25 C is investigated. Various mixtures of CH4, CO, CO2, N2, NH3, H2O, and H2 were utilized in different experiments. The yields of amino acids (1.2-4.7 percent based on the carbon) are found to be approximately independent of the H2/CH4 ratio and the presence of NH3, and a wide variety of amino acids are obtained. Glycine is found to be almost the only amino acid produced from CO and CO2 model atmospheres, with the maximum yield being about the same for the three carbon sources at high H2/carbon ratios,whereas CH4 is superior at low H2/carbon ratios. In addition, it is found that the directly synthesized NH3 together with the NH3 obtained from the hydrolysis of HCN, nitriles, and urea could have been a major source of ammonia in the atmosphere and oceans of the primitive earth. It is determined that prebiotic syntheses from HCN and H2CO to give products such as purines and sugars and some amino acids could have occurred in primitive atmospheres containing CO and CO2 provided the H2/CO and H2/CO2 ratios were greater than about 1.0.

Effect of prebiotics on the fecal microbiota of elderly volunteers after dietary supplementation of Bacillus coagulans GBI-30, 6086.

PubMed

Nyangale, Edna P; Farmer, Sean; Keller, David; Chernoff, David; Gibson, Glenn R

2014-12-01

In advancing age, gut populations of beneficial microbes, notably Bifidobacterium spp., show a marked decline. This contributes to an environment less capable of maintaining homoeostasis. This in vitro investigation studied the possible synergistic effects of probiotic supplementation in modulating the gut microbiota enabling prebiotic therapy to in elderly persons. Single stage batch culture anaerobic fermenters were used and inoculated with fecal microbiota obtained from volunteers after taking a 28 day treatment of Bacillus coagulans GBI-30, 6086 (GanedenBC30 (BC30)) or a placebo. The response to prebiotic supplements fructooligosaccharides (FOS) and galactooligosaccharides (GOS) in the fermenters was assessed. Bacterial enumeration was carried out using fluorescent in situ hybridisation and organic acids measured by gas chromatography. Baseline populations of Faecalibacterium prausnitzii, Clostridium lituseburense and Bacillus spp. were significantly higher in those having consumed BC30 compared to the placebo. Both prebiotics increased populations of several purportedly beneficial bacterial groups in both sets of volunteers. Samples from volunteers having ingested the BC30 also increased populations of C. lituseburense, Eubacterium rectale and F. prausnitzii more so than in persons who had consumed the placebo, this also resulted in significantly higher concentrations of butyrate, acetate and propionate. This shows that consumption of BC30 and subsequent use of prebiotics resulted in elevated populations of beneficial genres of bacteria as well as organic acid production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Template-directed chemistry and the origins of the RNA world

NASA Technical Reports Server (NTRS)

Kanavarioti, Anastassia

1994-01-01

Prompted by the growing number of reports about reactions catalyzed by ribozymes, this paper summarizes mechanistic and kinetic aspects of template-directed (TD) chemistry important for the synthesis of a diverse population of polynucleotides and analogues possibly up to 100 units long. Assuming that this chemistry takes place in a microenvironment conducive to life under the constant influx of mM concentrations of activated monomeric building blocks, the proposed scenario represents a working hypothesis for the prebiotic synthesis of the RNA world.

Abiogenic photochemical synthesis on surface of meteorites and other small space bodies

NASA Astrophysics Data System (ADS)

Simakov, Michael B.; Kuzicheva, Eugenia A.

The abiogenic photochemical synthesis of complex biochemical compounds on the surface of small bodies in our Solar system was examined. Hydrated minerals are found within a chondrite matrix of meteorites together with significant amounts of organic matter. Clays are likely to have formed when water was present on parent meteoritic bodies. In order to verify the existence of a relationship between abiogenic synthesis of nucleotides and inorganic components of the meteorites, we have investigated possible abiogenic reactions associated with different clay (montmorillonite, kaolinite) and a basaltic one (Tyatya's volcanic ash) under action of open space energy sources as a model of different exobiological environments on the surface of small space bodies. The abiogenic synthesis of natural adenine nucleotides from a mixture of adenosine and inorganic phosphate has been observed following irradiation with VUV light in the presence of different mineral samples. The yields of the products (5'AMP, 2'AMP, 3'AMP, 2'3'cAMP and 3'5'cAMP) depended on irradiation time and kinds of minerals used. The discovery that meteoritic organic compounds may be trapped and protected within a clay mineral matrix has implications for our understanding of prebiotic molecular evolution in the early Solar system. Clay minerals may also have concentrated organic compounds thereby promoting polymerization reactions. An adsorption/binding of nucleic acids components by clay crystals could change the electron distribution and/or the conformation of the molecules. The remnant water molecules in the clay sheets also could influence the course of the reaction. Clay immobilization of phosphate could play an important role in this reaction. Chondritic material could have been a common component of the inner Solar system shortly after its formation and the biologically useful products of clay mineral-organic matter interactions could have also widespread, and delivered to planetary surfaces through the accretion of carbonaceous asteroids.

An abiogenic photochemical synthesis on surface of meteorites and other small space bodies

NASA Astrophysics Data System (ADS)

Simakov, M.; Kuzicheva, E.

Abiogenic photochemical synthesis of complex biochemical compounds on the surface of small bodies in our Solar system was examined. The hydrated minerals are found within a chondrite matrix of meteorites together with significant amounts of organic matter. Clays are likely to have formed when water was presented on parent meteoritic bodies. In order to verify the existence of a relationship between abiogenic synthesis of nucleotides and inorganic components of the meteorites we have investigated possible abiogenic reactions at the presence of different clay minerals (montmorillonite, kaolinite) and basaltic sample (Tjatja's volcanic ash) under action of open space energy sources for modeling of different exobiological environments on the surface of small space bodies. The abiogenic synthesis of natural adenine nucleotides from mixture of adenosine plus inorganic phosphate has been observed under an irradiation with VUV radiation at the presence of different mineral samples. The yields of the products (5'AMP, 2'AMP, 3'AMP, 2'3'cAMP and 3'5'cAMP) were depended from irradiation time and kind of used minerals. The discovery that meteoritic organic compounds may be trapped and protected within a clay mineral matrix has implications for our understanding of prebiotic molecular evolution in the early Solar system. Clay minerals may have concentrated organic compounds thereby promoting polymerization reactions also. An adsorption/binding of nucleic acids components by clay crystals could change in the electron distribution and/or the conformation of the molecules. The remnant water molecules in the clay sheets also could influence on the course of the reaction. Besides, an immobilization of phosphate on clay also could play an important role in our reaction. Chondritic material would have been a common component of the inner Solar system shortly after its formation and the biologically useful products of clay mineral-organic matter interactions would have also widespread, and delivered to planetary surfaces through the accretion of carbonaceous asteroids.

Phosphorylation of Glyceric Acid in Aqueous Solution Using Trimetaphosphate

NASA Technical Reports Server (NTRS)

Kolb, Vera; Orgel, Leslie E.

1996-01-01

The phosphorylation of glyceric acid is an interesting prebiotic reaction because it converts a simple, potentially prebiotic organic molecule into phosphate derivatives that are central to carbohydrate metabolism. We find that 0.05 M glyceric acid in the presence of 0.5 M trimetaphosphate in alkaline solution gives a mixture of 2- and 3-phosphoglyceric acids in combined yields of up to 40%.

Carbon Monoxide and the Potential for Prebiotic Chemistry on Habitable Planets Around Main Sequence M Stars

NASA Technical Reports Server (NTRS)

Nava-Sedeno, J. Manik; Ortiz-Cervantes, Adrian; Segura, Antigona; Domagal-Goldman, Shawn D.

2016-01-01

Lifeless planets with CO2 atmospheres produce CO by CO2 photolysis. On planets around M dwarfs, CO is a long-lived atmospheric compound, as long as UV emission due to the stars chromospheric activity lasts, and the sink of CO and O2 in seawater is small compared to its atmospheric production. Atmospheres containing reduced compounds, like CO, may undergo further energetic and chemical processing to give rise to organic compounds of potential importance for the origin of life. We calculated the yield of organic compounds from CO2-rich atmospheres of planets orbiting M dwarf stars, which were previously simulated by Domagal- Goldman et al. (2014) and Harman et al. (2015), by cosmic rays and lightning using results of experiments by Miyakawaet al. (2002) and Schlesinger and Miller (1983a, 1983b). Stellar protons from active stars may be important energy sources for abiotic synthesis and increase production rates of biological compounds by at least 2 orders of magnitude compared to cosmic rays. Simple compounds such as HCN and H2CO are more readily synthesized than more complex ones, such as amino acids and uracil (considered here as an example), resulting in higher yields for the former and lower yields for the latter. Electric discharges are most efficient when a reducing atmosphere is present. Nonetheless, atmospheres with high quantities of CO2 are capable of producing higher amounts of prebiotic compounds, given that CO is constantly produced in the atmosphere. Our results further support planetary systems around M dwarf stars as candidates for supporting life or its origin.

The contribution of cometary volatiles to the primitive Earth.

PubMed

Oro, J; Holzer, G; Lazcano-Araujo, A

1980-01-01

It has been estimated that during its early history the Earth captured a mass of cometary material of the order of 10(23) grams. Since carbon is supposed to be at least three times more abundant in comets than in carbonaceous chondrites (3.5% C in C 1 chondrites), it can be deduced that about 1 x 10(22) grams of carbon (as carbon compounds), was added by comets to the surface of the prebiotic Earth. This carbon value is of the same order of magnitude as the value of the organic carbon buried in the Earth's sedimentary shell, but approximately one order of magnitude lower than the Earth's surface total carbon (7 x 10(22) gm). The capture of comets by the Earth would also have contributed to generating the appropriate aqueous and reducing environmental conditions necessary for organic synthesis. Although it is possible that some of the cometary carbon compounds falling on the Earth survived, most of them were probably decomposed by the heat and shock waves of the cometary collision. Upon quenching to low temperatures, however, the reactive chemical species produced by the impact would have recombined, leading to the synthesis of a great variety of organic molecules. Laboratory experiments with radiation, heat and shock waves have demonstrated that some of the synthesized compounds are biochemical molecules: amino acids, sugars, purines, and pyrimidines. These are essential to all living systems.

Natural Pyrrhotite as a Catalyst in Prebiotic Chemical Evolution

PubMed Central

López Ibáñez de Aldecoa, Alejandra; Velasco Roldán, Francisco; Menor-Salván, César

2013-01-01

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. PMID:25369819

Prebiotic Soup-Revisiting the Miller Experiment

NASA Technical Reports Server (NTRS)

Bada, Jeffrey L.; Lazcano, Antonio

2003-01-01

'Isn't life wonderful?' sang Alma Cogan and Les Howard in their almost forgotten 1953 hit. That same year, Stanley L. Miller raised the hopes of understanding the origin of life when on 15 May, Science published his paper on the synthesis of amino acids under conditions that simulated primitive Earth's atmosphere. Miller had applied an electric discharge to a mixture of CH4, NH3, H2O, and H2 - believed at the time to be the atmospheric composition of early Earth. Surprisingly, the products were not a random mixture of organic molecules, but rather a relatively small number of biochemically significant compounds such as amino acids, hydroxy acids, and urea. With the publication of these dramatic results, the modem era in the study of the origin of life began.

Prebiotic Soup: Revisiting the Miller Experiment

NASA Technical Reports Server (NTRS)

Bada, Jeffrey L.; Lazcano, Antonio

2003-01-01

Isn't life wonderful? sang Alma Cogan and Les Howard in their almost forgotten 1953 hit. That same year, Stanley L. Miller raised the hopes of understanding the origin of life when on 15 May, Science published his paper on the synthesis of amino acids under conditions that simulated primitive Earth's atmosphere. Miller had applied an electric discharge to a mixture of CH4, NH3, H2O, and H2 - believed at the time to be the atmospheric composition of early Earth. Surprisingly, the products were not a random mixture of organic molecules. but rather a relatively small number of biochemically significant compounds such as amino acids, hydroxy acids, and urea. With the publication of these dramatic results, the modern era in the study of the origin of life began.

Prebiotic synthesis of 5-substituted uracils: a bridge between the RNA world and the DNA-protein world.

PubMed

Robertson, M P; Miller, S L

1995-05-05

Under prebiotic conditions, formaldehyde adds to uracil at the C-5 position to produce 5-hydroxymethyluracil with favorable rates and equilibria. Hydroxymethyluracil adds a variety of nucleophiles, such as ammonia, glycine, guanidine, hydrogen sulfide, hydrogen cyanide, imidazole, indole, and phenol, to give 5-substituted uracils with the side chains of most of the 20 amino acids in proteins. These reactions are sufficiently robust that, if uracil had been present on the primitive Earth, then these substituted uracils would also have been present. The ribozymes of the RNA world would have included many of the functional groups found in proteins today, and their catalytic activities may have been considerably greater than presently assumed.

Prebiotic condensation reactions using cyanamide

NASA Technical Reports Server (NTRS)

Sherwood, E.; Nooner, D. W.; Eichberg, J.; Epps, D. E.; Oro, J.

1978-01-01

Condensation reactions in cyanamide, 4-amino-5-imidazole-carboxamide and cyanamide, imidazole systems under dehydrating conditions at moderate temperatures (60 to 100 deg C) were investigated. The cyanamide, imidazole system was used for synthesis of palmitoylglycerols from ammonium palmitate and glycerol. With the addition of deoxythymidine to the former system, P1, P2-dideoxythymidine 5 prime-phosphate was obtained; the same cyanamide, 4-amino-5-imidazole-carboxamide system was used to synthesize deoxythymidine oligonucleotides using deoxythymidine 5 prime-phosphate and deoxythymidine 5 prime-triphosphate, and peptides using glycine, phenylalanine or isoleucine with adenosine 5 prime-triphosphate. The pH requirements for these reactions make their prebiotic significance questionable; however, it is conceivable that they could occur in stable pockets of low interlayer acidity in a clay such as montmorillonite.

Prebiotic synthesis of 5-substituted uracils: a bridge between the RNA world and the DNA-protein world

NASA Technical Reports Server (NTRS)

Robertson, M. P.; Miller, S. L.

1995-01-01

Under prebiotic conditions, formaldehyde adds to uracil at the C-5 position to produce 5-hydroxymethyluracil with favorable rates and equilibria. Hydroxymethyluracil adds a variety of nucleophiles, such as ammonia, glycine, guanidine, hydrogen sulfide, hydrogen cyanide, imidazole, indole, and phenol, to give 5-substituted uracils with the side chains of most of the 20 amino acids in proteins. These reactions are sufficiently robust that, if uracil had been present on the primitive Earth, then these substituted uracils would also have been present. The ribozymes of the RNA world would have included many of the functional groups found in proteins today, and their catalytic activities may have been considerably greater than presently assumed.

Prebiotic effects: metabolic and health benefits.

PubMed

Roberfroid, Marcel; Gibson, Glenn R; Hoyles, Lesley; McCartney, Anne L; Rastall, Robert; Rowland, Ian; Wolvers, Danielle; Watzl, Bernhard; Szajewska, Hania; Stahl, Bernd; Guarner, Francisco; Respondek, Frederique; Whelan, Kevin; Coxam, Veronique; Davicco, Marie-Jeanne; Léotoing, Laurent; Wittrant, Yohann; Delzenne, Nathalie M; Cani, Patrice D; Neyrinck, Audrey M; Meheust, Agnes

2010-08-01

The different compartments of the gastrointestinal tract are inhabited by populations of micro-organisms. By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. For such a microbiota, 'normobiosis' characterises a composition of the gut 'ecosystem' in which micro-organisms with potential health benefits predominate in number over potentially harmful ones, in contrast to 'dysbiosis', in which one or a few potentially harmful micro-organisms are dominant, thus creating a disease-prone situation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim to propose a new definition of a prebiotic nor to identify which food products are classified as prebiotic but rather to validate and expand the original idea of the prebiotic concept (that can be translated in 'prebiotic effects'), defined as: 'The selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host.' Thanks to the methodological and fundamental research of microbiologists, immense progress has very recently been made in our understanding of the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. Thus the prebiotic effect is now a well-established scientific fact. The more data are accumulating, the more it will be recognised that such changes in the microbiota's composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of faecal concentrations of bifidobacteria. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. The use of particular food products with a prebiotic effect has thus been tested in clinical trials with the objective to improve the clinical activity and well-being of patients with such disorders. Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Often associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Numerous experimental studies have reported reduction in incidence of tumours and cancers after feeding specific food products with a prebiotic effect. Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density. Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect. However, the role of such changes in these health benefits remains to be definitively proven. As a result of the research activity that followed the publication of the prebiotic concept 15 years ago, it has become clear that products that cause a selective modification in the gut microbiota's composition and/or activity(ies) and thus strengthens normobiosis could either induce beneficial physiological effects in the colon and also in extra-intestinal compartments or contribute towards reducing the risk of dysbiosis and associated intestinal and systemic pathologies.

Dragonfly: In Situ Exploration of Titan's Organic Chemistry and Habitability

NASA Astrophysics Data System (ADS)

Turtle, E. P.; Barnes, J. W.; Trainer, M. G.; Lorenz, R. D.

2017-12-01

Titan's abundant complex carbon-rich chemistry, interior ocean, and past presence of liquid water on the surface make it an ideal destination to study prebiotic chemical processes and document the habitability of an extraterrestrial environment. Titan exploration is a high science priority due to the level of organic synthesis that it supports. Moreover, opportunities for organics to have interacted with liquid water at the surface (e.g., in impact melt sheets) increase the potential for chemical processes to progress further, providing an unparalleled opportunity to investigate prebiotic chemistry, as well as to search for signatures of potential water-based or even hydrocarbon-based life. The diversity of Titan's surface materials and environments drives the scientific need to be able to sample a variety of locations, thus mobility is key for in situ measurements. Titan's atmosphere is 4 times denser than Earth's reducing the wing/rotor area required to generate a given amount of lift, and the low gravity reduces the required magnitude of lift, making heavier-than-air mobility highly efficient. Dragonfly is a rotorcraft lander mission proposed to NASA's New Frontiers Program to take advantage of Titan's unique natural laboratory to understand how far chemistry can progress in environments that provide key ingredients for life. Measuring the compositions of materials in different environments will reveal how far organic chemistry has progressed. Surface material can be sampled into a mass spectrometer to identify the chemical components available and processes at work to produce biologically relevant compounds. Bulk elemental surface composition can be determined by a neutron-activated gamma-ray spectrometer. Meteorology measurements can characterize Titan's atmosphere and diurnal and spatial variations therein. Geologic features can be characterized via remote-sensing observations, which also provide context for samples. Seismic sensing can probe subsurface structure and activity. In addition to surface investigations, Dragonfly can perform measurements during flight, including atmospheric profiles and aerial observations of surface geology, which also provide sampling context and scouting for landing sites.

attempted prebiotic synthesis of pseudouridine

NASA Astrophysics Data System (ADS)

DWORKIN, JASON P.

1997-08-01

Pseudouridine is a modified base found in all tRNA and rRNA. Hence, it is reasonable to think that pseudouridine was important in the early evolution, if not the origin, of life. Since uracil reacts rapidly with formaldehyde and other aldehydes at the C-5 position, it is plausible that pseudouridine could be synthesized in a similar way by the reaction of the C-5 of uracil with the C-1 of ribose. The determining factor is whether the ribose could react with the uracil faster than ribose decomposes. However, both rates are determined by the amount of free aldehyde in the ribose. Various plausible prebiotic reactions were investigated and none showed pseudouridine above the detection limit (<0.01%). Only unreacted uracil and ribose decomposition products could be observed. Thus the rate of addition of ribose to uracil is much slower than the decomposition of ribose under any reasonable prebiotic conditions. Unless efficient non-biological catalysts for any of these reactions exist, pseudouridine would not have been synthesized to any significant extent without the use of biologically produced enzymes.

Attempted prebiotic synthesis of pseudouridine

NASA Technical Reports Server (NTRS)

Dworkin, J. P.; Miller, S. L. (Principal Investigator)

1997-01-01

Pseudouridine is a modified base found in all tRNA and rRNA. Hence, it is reasonable to think that pseudouridine was important in the early evolution, if not the origin, of life. Since uracil reacts rapidly with formaldehyde and other aldehydes at the C-5 position, it is plausible that pseudouridine could be synthesized in a similar way by the reaction of the C-5 of uracil with the C-1 of ribose. The determining factor is whether the ribose could react with the uracil faster than ribose decomposes. However, both rates are determined by the amount of free aldehyde in the ribose. Various plausible prebiotic reactions were investigated and none showed pseudouridine above the detection limit (<0.01%). Only unreacted uracil and ribose decomposition products could be observed. Thus the rate of addition of ribose to uracil is much slower than the decomposition of ribose under any reasonable prebiotic conditions. Unless efficient non-biological catalysts for any of these reactions exist, pseudouridine would not have been synthesized to any significant extent without the use of biologically produced enzymes.

Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles

NASA Astrophysics Data System (ADS)

Kuga, Maïa; Carrasco, Nathalie; Marty, Bernard; Marrocchi, Yves; Bernard, Sylvain; Rigaudier, Thomas; Fleury, Benjamin; Tissandier, Laurent

2014-05-01

The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic perspectives but also for overall comprehension of organic formation in the young Solar System and in planetary atmospheres. We have investigated abiotic synthesis of organics upon plasma discharge, with special attention to N isotope fractionation. Organic aerosols were synthesized from N2-CH4 and N2-CO gaseous mixtures using low-pressure plasma discharge experiments, aimed at simulating chemistry occurring in Titan's atmosphere and in the protosolar nebula, respectively. The nitrogen content, the N speciation and the N isotopic composition were analyzed in the resulting organic aerosols. Nitrogen is efficiently incorporated into the synthesized solids, independently of the oxidation degree, of the N2 content of the starting gas mixture, and of the nitrogen speciation in the aerosols. The aerosols are depleted in 15N by 15-25‰ relative to the initial N2 gas, whatever the experimental setup is. Such an isotopic fractionation is attributed to mass-dependent kinetic effect(s). Nitrogen isotope fractionation upon electric discharge cannot account for the large N isotope variations observed among Solar System objects and reservoirs. Extreme N isotope signatures in the Solar System are more likely the result of self-shielding during N2 photodissociation, exotic effect during photodissociation of N2 and/or low temperature ion-molecule isotope exchange. Kinetic N isotope fractionation may play a significant role in the Titan's atmosphere. On the Titan's night side, 15N-depletion resulting from electron driven reactions may counterbalance photo-induced 15N enrichments occurring on the day's side. We also suggest that the low δ15N values of Archaean organic matter (Beaumont and Robert, 1999) are partly the result of abiotic synthesis of organics that occurred at that time, and that the subsequent development of the biosphere resulted in shifts of δ15N towards higher values.

Promising Prebiotic Candidate Established by Evaluation of Lactitol, Lactulose, Raffinose, and Oligofructose for Maintenance of a Lactobacillus-Dominated Vaginal Microbiota

PubMed Central

McMillan, Amy; Seney, Shannon; van der Veer, Charlotte; Kort, Remco; Sumarah, Mark W.

2017-01-01

ABSTRACT Perturbations to the vaginal microbiota can lead to dysbiosis, including bacterial vaginosis (BV), which affects a large portion of the female population. In a healthy state, the vaginal microbiota is characterized by low diversity and colonization by Lactobacillus spp., whereas in BV, these species are displaced by a highly diverse population of bacteria associated with adverse vaginal health outcomes. Since prebiotic ingestion has been a highly effective approach to invigorate lactobacilli for improved intestinal health, we hypothesized that these compounds could stimulate lactobacilli at the expense of BV organisms to maintain vaginal health. Monocultures of commensal Lactobacillus crispatus, Lactobacillus vaginalis, Lactobacillus gasseri, Lactobacillus johnsonii, Lactobacillus jensenii, and Lactobacillus iners, in addition to BV-associated organisms and Candida albicans, were tested for their ability to utilize a representative group of prebiotics consisting of lactitol, lactulose, raffinose, and oligofructose. The disaccharide lactulose was found to most broadly and specifically stimulate vaginal lactobacilli, including the strongly health-associated species L. crispatus, and importantly, not to stimulate BV organisms or C. albicans. Using freshly collected vaginal samples, we showed that exposure to lactulose promoted commensal Lactobacillus growth and dominance and resulted in healthy acidity partially through lactic acid production. This provides support for further testing of lactulose to prevent dysbiosis and potentially to reduce the need for antimicrobial agents in managing vaginal health. IMPORTANCE Bacterial vaginosis (BV) and other dysbioses of the vaginal microbiota significantly affect the quality of life of millions of women. Antimicrobial therapy is often poorly effective, causes side effects, and does not prevent recurrences. We report one of very few studies that have evaluated how prebiotics—compounds that are selectively fermented by beneficial bacteria such as Lactobacillus spp.—can modulate the vaginal microbiota. We also report use of a novel in vitro polymicrobial model to study the impact of prebiotics on the vaginal microbiota. The identification of prebiotic lactulose as enhancing Lactobacillus growth but not that of BV organisms or Candida albicans has direct application for retention of homeostasis and prevention of vaginal dysbiosis and infection. PMID:29269494

New Insights into Prebiotic Chemistry from Old Archived Miller Extracts

NASA Technical Reports Server (NTRS)

Parker, Eric T.; Cleaves, H. James; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael P.; Aubrey, Andrew D.; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Following the discovery of an archived set of samples from Stanley Miller's early experiments, analyses were undertaken to better understand the diversity of compounds produced from electric discharges acting on reducing gas mixtures. The paper chromatography methods that Miller used in the 1950s were only capable of detecting a few amino acids and were unable to provide substantial quantitative data relative to today's techniques. Current analytical techniques are much more sensitive and selective, and are capable of precisely quantifying a much larger range of amino acids and their enantiomeric abundances. In one study, preserved dried samples produced by Miller using a lesser-known volcanic apparatus which differed from Miller's classic apparatus in that it utilized an aspirator that injected steam into the electric discharge chamber, simulating a volcanic eruption. The volcanic apparatus produced a wider variety of amino acids than the classic configuration. Prebiotic compounds synthesized in these environments may have locally accumulated where they could have undergone further processing. An additional preserved set of samples from an experiment conducted in 1958 were also found in Miller's archived collection. These samples which had been generated using a mixture of CH4, NH3, H2S and CO2 were collected, catalogued, and stored by Miller, but for unknown reasons were never studied. In our analyses a total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of amino butyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller in these experiments may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments. Although experiments using a variety of gases as components of the primordial Earth's atmospheric composition and a spark discharge apparatus configured according to Miller's original or volcanic design can be readily carried out, the unique opportunity to investigate samples prepared by the pioneer in abiotic synthesis using state of the art analytical methods is of considerable historic interest.

On the origin and early evolution of biological catalysis and other studies on chemical evolution

NASA Technical Reports Server (NTRS)

Oro, J.; Lazcano, A.

1991-01-01

One of the lines of research in molecular evolution which we have developed for the past three years is related to the experimental and theoretical study of the origin and early evolution of biological catalysis. In an attempt to understand the nature of the first peptidic catalysts and coenzymes, we have achieved the non-enzymatic synthesis of the coenzymes ADPG, GDPG, and CDP-ethanolamine, under conditions considered to have been prevalent on the primitive Earth. We have also accomplished the prebiotic synthesis of histidine, as well as histidyl-histidine, and we have measured the enhancing effects of this catalytic dipeptide on the dephosphorylation of deoxyribonucleotide monophosphates, the hydrolysis of oligo A, and the oligomerization 2', 3' cAMP. We reviewed and further developed the hypothesis that RNA preceded double stranded DNA molecules as a reservoir of cellular genetic information. This led us to undertake the study of extant RNA polymerases in an attempt to discover vestigial sequences preserved from early Archean times. In addition, we continued our studies of on the chemical evolution of organic compounds in the solar system and beyond.

Isolation of Purines and Pyrimidines from the Murchison Meteorite

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Bada, J. K.

2003-01-01

The origin of life on Earth, and possibly on other planets such as Mars, would have required the presence of liquid water and a continuous supply of prebiotic organic compounds. The delivery of organic matter by asteroids, comets, and carbonaceous meteorites could have contributed to the early Earth's prebiotic inventory by seeding the planet with biologically important organic compounds. A wide variety of prebiotic organic compounds have previously been detected in the Murchison CM type carbonaceous chondrite including amino acids, purines and pyrimidines'. These compounds play a major role in terrestrial biochemistry and are integral components of proteins, DNA and RNA. In this study we developed a new extraction technique using sublimation in order to isolate purines and pyrimidines from Murchison2, which is cleaner and more time efficient that traditional methods3. Several purines including adenine, guanine, hypoxanthine and xanthine were positively identified by high performance liquid chromatography and ultraviolet absorption detection in our Murchison extracts. The purines detected in Murchison do not correlate with the distribution of nucleobases found in geological environments on Earth4. Moreover, the abundance of extraterrestrial amino acids and the low level of terrestrial amino acid contaminants found in Murchison', support the idea that the purines in t h s meteorite are extraterrestrial in origin.

Abiotic Synthesis of Nucleic Acids: Hypochromicity and Future Research

NASA Technical Reports Server (NTRS)

Glass, K.; Oye, M.; Deamer, D.; Vercoutere, W.

2017-01-01

The earliest forms of life would likely have a protocellular form, with a membrane encapsulating some form of linear charged polymer. These polymers could have enzymatic as well as genetic properties. We can simulate plausible prebiotic conditions in the laboratory to test hypotheses related to this concept. In earlier work we have shown that mononucleotides organized within a multilamellar lipid matrix can produce oligomers in the anhydrous phase of dehydration- rehydration cycles (Rajamani, 2008). If mononucleotides are in solution at millimolar concentrations, then oligomers resembling RNA are synthesized and exist in a steady state with their monomers DeGuzman, 2014). We have used conventional and novel techniques to demonstrate that secondary structures stabilized by hydrogen bonds may be present in the condensation products produced in dehydration- rehydration cycles that simulate hydrothermal fields that were present on the early Earth. Gel electrophoresis data corroborates the presence of up to 200-base pair length RNA fragments in products of Hydration-Dehydration experiments. Furthermore, hypochromicity measurements demonstrate a degree of hypochromicity found in single RNA strand of known sequence, as well as results that indicate this is true also for a sample of complementary strands of RNA. Analysis of ionic current signatures of known RNA hairpin molecule as measured using a nanopore detector indicate a significant variability in pattern, different from the signatures produced by DNA hairpin molecules. This informs how we may interpret nanopore data gathered from prebiotic simulations.

Self-Assembly of Prebiotic Organic Materials from Impact Events of Amino Acid Solutions

NASA Astrophysics Data System (ADS)

Goldman, Nir

2017-06-01

Proteinogenic amino acids can be produced on or delivered to a planet via abiotic sources and were consequently likely present before the emergence of life on early Earth. However, the role that these materials played in the in the emergence of life remains an open question, in part because little is known about the survivability and reactivity of astrophysical prebiotic compounds upon impact with a planetary surface. To this end, we have used a force matched semi-empirical quantum simulation method in development in our group to study oblique impacts of aqueous glycine solutions at conditions of up to 40 GPa and 3000 K. We find that these elevated conditions induce the formation of glycine-oligomeric structures with a number of different chemical moieties such as hydroxyl and amine groups diffusing on and off the C-N backbones. The C-N backbones of these structures generally remain stable during cooling and expansion, yielding relatively large three-dimensional molecules that contain a number of different functional groups and embedded bonded regions akin to oligo-peptides. Our results help determine the role of comets and other celestial bodies in both the delivery and synthesis of polypeptides and homochirality to early Earth. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Prebiotic synthesis and reactions of nucleosides and nucleotides

NASA Technical Reports Server (NTRS)

Ferris, J. P.; Yanagawa, H.; Hagan, W. J., Jr.

1983-01-01

The potential of diiminosuccinonitrile (DISN) as a prebiotic phosphorylating agent is studied. This compound is formed readily by the oxidation of diaminomaleonitrile, a tetramer of HCN. DISN is shown to produce the cyclization of 3'-adenosine monophosphate to adenosine 2',3'-cyclic phosphate in up to 40 percent yield. The DISN-mediated phosphorylation of uridine to uridine monophosphate is determined not to proceed efficiently in aqueous solution. The reaction of DISN and BrCN with uridine-5'-phosphate and uridine is found to result in the formation of 2,2'-anhydronucleotides and 2,2'-anhydronucleosides, respectively, and other reaction products resulting from an initial reaction at the 2' and 3'-hydroxyl groups. Homoionic montmorillonites were employed to study the clay mineral catalysis of the cyclization of adenosine-3'-phosphate.

Formation of nucleoside 5'-polyphosphates from nucleotides and trimetaphosphate

NASA Technical Reports Server (NTRS)

Lohrmann, R.

1975-01-01

Nucleoside 5'-polyphosphates (N5PP) formed when solutions of nucleoside 5'-phosphates (N5P) and trimetaphosphate (TMP) are dessicated at room temperature are studied by paper chromatography, electrophoresis, and metal catalytic reactions. Divalent Mg ion exhibited superior catalytic function to other divalent metal ions in the reaction. Major reaction products are indicated. The importance of the N5PP series, TMP, and N5-triphosphate as substrates of RNA and DNA synthesis, and under postulated prebiotic conditions likely to obtain during prebiological ages of the earth, is emphasized and discussed. Alternate drying and wetting, evaporation from a prebiotic puddle, concentration of solubles in the remaining liquid phase, metal catalysis, and the role of these substances in the formation of amino acids and long-chain polyphosphates are considered.

Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents

NASA Astrophysics Data System (ADS)

Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua

2017-12-01

Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H2 and CO2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.

Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents.

PubMed

Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua

2017-12-01

Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H 2 and CO 2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.

Enantiomeric excesses induced in amino acids by ultraviolet circularly polarized light irradiation of extraterrestrial ice analogs: A possible source of asymmetry for prebiotic chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Modica, Paola; De Marcellus, Pierre; D'Hendecourt, Louis Le Sergeant

2014-06-10

The discovery of meteoritic amino acids with enantiomeric excesses of the L-form (ee {sub L}) has suggested that extraterrestrial organic materials may have contributed to prebiotic chemistry and directed the initial occurrence of the ee {sub L} that further led to homochirality of amino acids on Earth. A proposed mechanism for the origin of ee {sub L} in meteorites involves an asymmetric photochemistry of extraterrestrial ices by UV circularly polarized light (CPL). We have performed the asymmetric synthesis of amino acids on achiral extraterrestrial ice analogs by VUV CPL, investigating the chiral asymmetry transfer at two different evolutionary stages atmore » which the analogs were irradiated (regular ices and/or organic residues) and at two different photon energies (6.6 and 10.2 eV). We identify 16 distinct amino acids and precisely measure the L-enantiomeric excesses using the enantioselective GC × GC-TOFMS technique in five of them: α-alanine, 2,3-diaminopropionic acid, 2-aminobutyric acid, valine, and norvaline, with values ranging from ee {sub L} = –0.20% ± 0.14% to ee {sub L} = –2.54% ± 0.28%. The sign of the induced ee {sub L} depends on the helicity and the energy of CPL, but not on the evolutionary stage of the samples, and is the same for all five considered amino acids. Our results support an astrophysical scenario in which the solar system was formed in a high-mass star-forming region where icy grains were irradiated during the protoplanetary phase by an external source of CPL of a given helicity and a dominant energy, inducing a stereo-specific photochemistry.« less

Enantiomeric Excesses Induced in Amino Acids by Ultraviolet Circularly Polarized Light Irradiation of Extraterrestrial Ice Analogs: A Possible Source of Asymmetry for Prebiotic Chemistry

NASA Astrophysics Data System (ADS)

Modica, Paola; Meinert, Cornelia; de Marcellus, Pierre; Nahon, Laurent; Meierhenrich, Uwe J.; Le Sergeant d'Hendecourt, Louis

2014-06-01

The discovery of meteoritic amino acids with enantiomeric excesses of the L-form (ee L) has suggested that extraterrestrial organic materials may have contributed to prebiotic chemistry and directed the initial occurrence of the ee L that further led to homochirality of amino acids on Earth. A proposed mechanism for the origin of ee L in meteorites involves an asymmetric photochemistry of extraterrestrial ices by UV circularly polarized light (CPL). We have performed the asymmetric synthesis of amino acids on achiral extraterrestrial ice analogs by VUV CPL, investigating the chiral asymmetry transfer at two different evolutionary stages at which the analogs were irradiated (regular ices and/or organic residues) and at two different photon energies (6.6 and 10.2 eV). We identify 16 distinct amino acids and precisely measure the L-enantiomeric excesses using the enantioselective GC × GC-TOFMS technique in five of them: α-alanine, 2,3-diaminopropionic acid, 2-aminobutyric acid, valine, and norvaline, with values ranging from ee L = -0.20% ± 0.14% to ee L = -2.54% ± 0.28%. The sign of the induced ee L depends on the helicity and the energy of CPL, but not on the evolutionary stage of the samples, and is the same for all five considered amino acids. Our results support an astrophysical scenario in which the solar system was formed in a high-mass star-forming region where icy grains were irradiated during the protoplanetary phase by an external source of CPL of a given helicity and a dominant energy, inducing a stereo-specific photochemistry.

Biosynthetic porphyrins and the origin of photosynthesis

NASA Technical Reports Server (NTRS)

Mauzerall, D.; Ley, A.; Mercer-Smith, J. A.

1986-01-01

Since the prebiotic atmosphere was anaerobic, if not reducing, a useful function of primordial photosynthesis would have been to photooxidize reduced substrates such as Fe(+2), S(-2) or reduced organic molecules and to emit hydrogen. Experiments have shown that the early biogenic pigments uroporphyrin and coproporphyrin do photooxidize organic compounds and emit hydrogen in the presence of a platinum catalyst. These experiments were carried out in dilute aqueous solution near neutral pH under anaerobic atmosphere, and quantum yields near 10-2 were obtained. Thus relevant prebiotic conditions were maintained. Rather then to further optimize conditions, attempts were made to replace the platinum catalyst by a more prebiotically suitable catalyst. Trials with an Fe4S4(SR)4 cluster, in analogy to the present hydrogenase and nitrogenase, were not successful. However, experiments using cobalt complexes to catalyze the formation of hydrogen are promising. In analogy with biological photosynthetic systems which group pigments, electron transfer molecules and enzymes in clusters for efficiency, it was found that binding the biogenic porphyrins to the polyvinyl alcohol used to support the platinum catalyst did increase the quantum yield of the reaction. It was also found that ultraviolet light can serve to photo-oxidize porphyrinogens to porphyrins under anaerobic conditions. Thus the formation of the colorless porphyriogens by the extraordinarily simple biosynthetic pathway would not be a problem because of the prevalence of UV light in the prebiotic, anoxic atmosphere.

Oligoglyceric acid synthesis by autocondensation of glyceroyl thioester

NASA Technical Reports Server (NTRS)

Weber, A. L.

1986-01-01

The autocondensation of the glyceroyl thioester, S-glyceroyl-ethane-thiol, yielded olioglyceric acid. The rates of autocondensation and hydrolysis of the thioester increased from pH 6.5 to pH 7.5 in 2,6-lutidine and imidazole buffers. Autocondensation and hydrolysis were much more rapid in imidazole buffers as compared to 2,6-lutidine and phosphate buffers. The efficiency of ester bond synthesis was about 20% for 40 mM S-glyceroyl-ethane-thiol in 2,6-lutidine and imidazole buffers near neutral pH. The size and yield of the olioglyceric acid products increased when the concentration of the thioester was increased. The relationship of these results to prebiotic polymer synthesis is discussed.

Borate minerals and origin of the RNA world.

PubMed

Grew, Edward S; Bada, Jeffrey L; Hazen, Robert M

2011-08-01

The RNA World is generally thought to have been an important link between purely prebiotic (>3.7 Ga) chemistry and modern DNA/protein biochemistry. One concern about the RNA World hypothesis is the geochemical stability of ribose, the sugar moiety of RNA. Prebiotic stabilization of ribose by solutions associated with borate minerals, notably colemanite, ulexite, and kernite, has been proposed as one resolution to this difficulty. However, a critical unresolved issue is whether borate minerals existed in sufficient quantities on the primitive Earth, especially in the period when prebiotic synthesis processes leading to RNA took place. Although the oldest reported colemanite and ulexite are 330 Ma, and the oldest reported kernite, 19 Ma, boron isotope data and geologic context are consistent with an evaporitic borate precursor to 2400-2100 Ma borate deposits in the Liaoning and Jilin Provinces, China, as well as to tourmaline-group minerals at 3300-3450 Ma in the Barberton belt, South Africa. The oldest boron minerals for which the age of crystallization could be determined are the metamorphic tourmaline species schorl and dravite in the Isua complex (metamorphism between ca. 3650 and ca. 3600 Ma). Whether borates such as colemanite, ulexite and kernite were present in the Hadean (>4000 Ma) at the critical juncture when prebiotic molecules such as ribose required stabilization depends on whether a granitic continental crust had yet differentiated, because in its absence we see no means for boron to be sufficiently concentrated for borates to be precipitated.

Lightning and Life on Exoplanets

NASA Astrophysics Data System (ADS)

Rimmer, Paul; Ardaseva, Aleksandra; Hodosan, Gabriella; Helling, Christiane

2016-07-01

Miller and Urey performed a ground-breaking experiment, in which they discovered that electric discharges through a low redox ratio gas of methane, ammonia, water vapor and hydrogen produced a variety of amino acids, the building blocks of proteins. Since this experiment, there has been significant interest on the connection between lightning chemistry and the origin of life. Investigation into the atmosphere of the Early Earth has generated a serious challenge for this project, as it has been determined both that Earth's early atmosphere was likely dominated by carbon dioxide and molecular nitrogen with only small amounts of hydrogen, having a very high redox ratio, and that discharges in gases with high redox ratios fail to yield more than trace amounts of biologically relevant products. This challenge has motivated several origin of life researchers to abandon lightning chemistry, and to concentrate on other pathways for prebiotic synthesis. The discovery of over 2000 exoplanets includes a handful of rocky planets within the habitable zones around their host stars. These planets can be viewed as remote laboratories in which efficient lightning driven prebiotic synthesis may take place. This is because many of these rocky exoplanets, called super-Earths, have masses significantly greater than that of Earth. This higher mass would allow them to more retain greater amounts hydrogen within their atmosphere, reducing the redox ratio. Discharges in super-Earth atmospheres can therefore result in a significant yield of amino acids. In this talk, I will discuss new work on what lightning might look like on exoplanets, and on lightning driven chemistry on super-Earths. Using a chemical kinetics model for a super-Earth atmosphere with smaller redox ratios, I will show that in the presence of lightning, the production of the amino acid glycine is enhanced up to a certain point, but with very low redox ratios, the production of glycine is again inhibited. I will conclude with a discussion on a promising alternative to lightning driven prebiotic chemistry, ultraviolet light (UV) driven chemistry, and will discuss why a UV source breaking bonds seems more effective than lightning shocks at producing a variety of prebiotic species.

A possible prebiotic synthesis of pantetheine, a precursor to coenzyme A.

PubMed

Keefe, A D; Newton, G L; Miller, S L

1995-02-23

The involvement of coenzyme A in many enzyme reactions suggests that it acted in this capacity very early in the development of life on Earth. Particularly relevant in this regard is its role in the activation of amino acids and hydroxy acids in the biosynthesis of some peptide antibiotics--a mechanism of peptide synthesis that forms the basis for the proposal that a thioester world could have preceded the RNA world. The components of coenzyme A have been shown to be probable prebiotic compounds: beta-alanine, pantoyl lactone and cysteamine and possibly adenosine. We show here that the pantetheine moiety of coenzyme A (which also occurs in a number of enzymes) can be synthesized in yields of several per cent by heating pantoyl lactone, beta-alanine and cysteamine at temperatures as low as 40 degrees C. These components are extremely soluble and so would have been preferentially concentrated in evaporating bodies of water, for example on beaches and at lagoon margins. Our results show that amide bonds can be formed at temperatures as low as 40 degrees C, and provide circumstantial support for the suggestion that pantetheine and coenzyme A were important in the earliest metabolic systems.

A possible prebiotic synthesis of pantetheine, a precursor to coenzyme A

NASA Technical Reports Server (NTRS)

Keefe, A. D.; Newton, G. L.; Miller, S. L.

1995-01-01

The involvement of coenzyme A in many enzyme reactions suggests that it acted in this capacity very early in the development of life on Earth. Particularly relevant in this regard is its role in the activation of amino acids and hydroxy acids in the biosynthesis of some peptide antibiotics--a mechanism of peptide synthesis that forms the basis for the proposal that a thioester world could have preceded the RNA world. The components of coenzyme A have been shown to be probable prebiotic compounds: beta-alanine, pantoyl lactone and cysteamine and possibly adenosine. We show here that the pantetheine moiety of coenzyme A (which also occurs in a number of enzymes) can be synthesized in yields of several per cent by heating pantoyl lactone, beta-alanine and cysteamine at temperatures as low as 40 degrees C. These components are extremely soluble and so would have been preferentially concentrated in evaporating bodies of water, for example on beaches and at lagoon margins. Our results show that amide bonds can be formed at temperatures as low as 40 degrees C, and provide circumstantial support for the suggestion that pantetheine and coenzyme A were important in the earliest metabolic systems.

Rates of Decomposition of Ribose and other Sugars: Implications for Chemical Evolution

NASA Technical Reports Server (NTRS)

Larralde, Rosa; Robertson, Michael P.; Miller, Stanley L.

1995-01-01

The existence of the RNA world, in which RNA acted as a catalyst as well as an informational macromolecule, assumes a large prebiotic source of ribose or the existence of pre-RNA molecules with backbones different from ribose-phosphate. The generally accepted prebiotic synthesis of ribose, the formose reaction, yields numerous sugars without any selectivity. Even if there were a selective synthesis of ribose, there is still the problem of stability. Sugars are known to be unstable in strong acid or base, but there are few data for neutral solutions. Therefore, we have measured the rate of decomposition of ribose between pH 4 and pH 8 from 40 C to 120 C. The ribose half-lives are very short (73 min at pH 7.0 and 100 C and 44 years at pH 7.0 and 0 C). The other aldopentoses and aldohexoses have half-lives within an order of magnitude of these values, as do 2-deoxyribose, ribose 5-phosphate, and ribose 2,4bisphosphate. These results suggest that the backbone of the first genetic material could not have contained ribose or other sugars because of their instability.

A prebiotic template-directed peptide synthesis based on amyloids.

PubMed

Rout, Saroj K; Friedmann, Michael P; Riek, Roland; Greenwald, Jason

2018-01-16

The prebiotic replication of information-coding molecules is a central problem concerning life's origins. Here, we report that amyloids composed of short peptides can direct the sequence-selective, regioselective and stereoselective condensation of amino acids. The addition of activated DL-arginine and DL-phenylalanine to the peptide RFRFR-NH 2 in the presence of the complementary template peptide Ac-FEFEFEFE-NH 2 yields the isotactic product FRFRFRFR-NH 2 , 1 of 64 possible triple addition products, under conditions in which the absence of template yields only single and double additions of mixed stereochemistry. The templating mechanism appears to be general in that a different amyloid formed by (Orn)V(Orn)V(Orn)V(Orn)V-NH 2 and Ac-VDVDVDVDV-NH 2 is regioselective and stereoselective for N-terminal, L-amino-acid addition while the ornithine-valine peptide alone yields predominantly sidechain condensation products with little stereoselectivity. Furthermore, the templating reaction is stable over a wide range of pH (5.6-8.6), salt concentration (0-4 M NaCl), and temperature (25-90 °C), making the amyloid an attractive model for a prebiotic peptide replicating system.

Selective derivatization and sequestration of ribose from a prebiotic mix.

PubMed

Springsteen, Greg; Joyce, Gerald F

2004-08-11

Observations regarding the catalytic potential of RNA and the role of RNA in biology have formed the basis for the "RNA world" hypothesis, which suggests that a genetic system based on self-replicating polyribonucleotides preceded modern biology. However, attempts to devise a realistic prebiotic synthesis of nucleic acids from simple starting materials have been plagued by problems of poor chemical selectivity, lack of stereo- and regiospecificity, and similar rates of formation and degradation of some of the key intermediates. For example, ribose would have been only a small component of a highly complex mix of sugars resulting from the condensation of formaldehyde in a prebiotic world. In addition, ribose is more reactive and degrades more rapidly compared with most other monosaccharides. This study demonstrates an approach for the preferential sequestration of ribose relative to other sugars that takes advantage of its greater reactivity. Cyanamide reacts especially rapidly with ribose to form a stable bicyclic adduct. This product crystallizes spontaneously in aqueous solution, whereas the corresponding products derived from threose, galactose, glucose, mannose, and each of the other pentoses do not. Furthermore, when employing a racemic mixture of d- and l-ribose, enantiomerically twinned crystals are formed that contain discrete homochiral domains.

Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

NASA Technical Reports Server (NTRS)

Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

1999-01-01

The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

Dragonfly: Exploring Titan's Surface with a New Frontiers Relocatable Lander

NASA Astrophysics Data System (ADS)

Barnes, Jason W.; Turtle, Elizabeth P.; Trainer, Melissa G.; Lorenz, Ralph

2017-10-01

We proposed to the NASA New Frontiers 4 mission call a lander to assess Titan's prebiotic chemistry, evaluate its habitability, and search for biosignatures on its surface. Titan as an Ocean World is ideal for the study of prebiotic chemical processes and the habitability of an extraterrestrial environment due to its abundant complex carbon-rich chemistry and because both liquid water and liquid hydrocarbons can occur on its surface. Transient liquid water surface environments can be created by both impacts and cryovolcanic processes. In both cases, the water could mix with surface organics to form a primordial soup. The mission would sample both organic sediments and water ice to measure surface composition, achieving surface mobility by using rotors to take off, fly, and land at new sites. The Dragonfly rotorcraft lander can thus convey a single capable instrument suite to multiple locations providing the capability to explore diverse locations 10s to 100s of kilometers apart to characterize the habitability of Titan's environment, investigate how far prebiotic chemistry has progressed, and search for chemical signatures indicative of water- and/or hydrocarbon-based life.

The persistent and pernicious myth of the early CO2-N2 atmospheres of terrestrial planets

NASA Astrophysics Data System (ADS)

Shaw, G. H.

2009-12-01

The accepted model for early atmospheres of terrestrial planets has settled on a CO2-N2 composition. Unfortunately, while it is largely based on a brilliant geological analysis by Rubey, there is no compelling evidence whatsoever for such a composition as the first “permanent” atmosphere for Earth or any other planet. In fact, geological discoveries of the past 50+ years reveal several problems with a CO2-N2 atmosphere, some of which Rubey recognized in his own analysis. He clearly addressed the problem of timing of degassing, concluding that early massive degassing of CO2 would produce readily observed and profound effects, which are not evident. Modeling and constraints on the timing of planetary accretion and core formation indicate massive early degassing. If early degassing emitted CO2-N2, the effects are concealed. Plate tectonic recycling is not a solution, as conditions would have persisted beyond the time of the earliest rocks, which do not show the effects. Attempts to return degassed CO2 to the mantle are not only ad hoc, but inconsistent with early thermal structure of the Earth. Second, production of prebiotic organic compounds from a CO2-N2 atmosphere has been a nagging problem. At best this has been addressed by invoking hydrogen production from the mantle to provide reducing capacity. While hydrogen may be emitted in volcanic eruptions, it is exceedingly difficult to imagine this process generating enough organics to yield high concentrations in a global ocean. The recent fashion of invoking organic synthesis at deep-sea vents suffers from the same problem: how to achieve sufficient concentrations of organics in a global ocean by abiotic synthesis when hydrothermal activity stirs the solution and carries the prebiotic products off to great dilution? Suggesting life began at deep-sea vents, and continues to carry on chemosynthesis there, begs the question. Unless you get high enough concentrations of prebiotics by abiotic processes, you simply don’t get life. Third, solutions invoking high atmospheric CO2 as the answer to the faint young sun problem encounter exactly the same problems associated with prompt degassing of CO2. Fourth, the carbon isotope record, in which early carbonaceous deposits show signs of photosynthetic fractionation of carbon are problematical if most of the primary surface and near-surface carbon was CO2. Finally, the delay in oxidation of Earth’s surface following oxygenic photosynthesis is problematical if early photosynthesizers had a vast CO2 source from early degassing. Given an abundant food supply, what prevented early cyanobacteria from rapidly oxidizing the surface? Although discovery of CO2-rich atmospheres on Venus and Mars seem to support CO2 as the primary surface carbon reservoir, these atmospheres are the result of atmospheric evolution, particularly loss of H to space. ALL of these problems disappear with early degassing of reduced gases such as CH4 and NH3. Considerations of meteoritic compositions, accretionary processes, and early atmosphere/hydrosphere chemical processing all support reduced gases as dominant in the early atmospheres of the terrestrial planets. The time has come to revert to any earlier idea of strongly reducing conditions on early terrestrial planet surfaces, followed by long-term evolutionary trends toward oxidation.

Prebiotic Oxidative Polymerization of 2,3 Dimercaptopropanol on the Surface of Iron(III) Hydroxide Oxide

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1994-01-01

The oxidation of 2,3-Dimercapto-1-propanol by ferric ions on the surface of iron (III) hydroxide oxide yielded polydisulfide polymers. This polymerization occured readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron (III) hydroxide oxide (20 mg, 160 micro mole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the mineral phase. Reactions at higher dithiol concentrations with the same ratio of dithiol to mineral gave a higher yield of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis will be discussed.

A Fluorescent G-quadruplex Sensor for Chemical RNA Copying.

PubMed

Giurgiu, Constantin; Wright, Tom; O'Flaherty, Derek; Szostak, Jack

2018-06-25

Non-enzymatic RNA replication may have been one of the processes involved in the appearance of life on Earth. Attempts to recreate this process in a laboratory setting have not been successful thus far, highlighting a critical need for finding prebiotic conditions that increase the rate and the yield. Here, we present a highly parallel assay for template directed RNA synthesis that relies on the intrinsic fluorescence of a 2-aminopurine modified G-quadruplex. We demonstrate the application of the assay to examine the combined influence of multiple variables including pH, divalent metal concentrations and ribonucleotide concentrations on the copying of RNA sequences. The assay enables a direct survey of physical and chemical conditions, potentially prebiotic, which could enable the chemical replication of RNA. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low-energy electron-induced chemistry of condensed methanol: implications for the interstellar synthesis of prebiotic molecules.

PubMed

Boamah, Mavis D; Sullivan, Kristal K; Shulenberger, Katie E; Soe, ChanMyae M; Jacob, Lisa M; Yhee, Farrah C; Atkinson, Karen E; Boyer, Michael C; Haines, David R; Arumainayagam, Christopher R

2014-01-01

In the interstellar medium, UV photolysis of condensed methanol (CH3OH), contained in ice mantles surrounding dust grains, is thought to be the mechanism that drives the formation of "complex" molecules, such as methyl formate (HCOOCH3), dimethyl ether (CH3OCH3), acetic acid (CH3COOH), and glycolaldehyde (HOCH2CHO). The source of this reaction-initiating UV light is assumed to be local because externally sourced UV radiation cannot penetrate the ice-containing dark, dense molecular clouds. Specifically, exceedingly penetrative high-energy cosmic rays generate secondary electrons within the clouds through molecular ionizations. Hydrogen molecules, present within these dense molecular clouds, are excited in collisions with these secondary electrons. It is the UV light, emitted by these electronically excited hydrogen molecules, that is generally thought to photoprocess interstellar icy grain mantles to generate "complex" molecules. In addition to producing UV light, the large numbers of low-energy (< 20 eV) secondary electrons, produced by cosmic rays, can also directly initiate radiolysis reactions in the condensed phase. The goal of our studies is to understand the low-energy, electron-induced processes that occur when high-energy cosmic rays interact with interstellar ices, in which methanol, a precursor of several prebiotic species, is the most abundant organic species. Using post-irradiation temperature-programmed desorption, we have investigated the radiolysis initiated by low-energy (7 eV and 20 eV) electrons in condensed methanol at - 85 K under ultrahigh vacuum (5 x 10(-10) Torr) conditions. We have identified eleven electron-induced methanol radiolysis products, which include many that have been previously identified as being formed by methanol UV photolysis in the interstellar medium. These experimental results suggest that low-energy, electron-induced condensed phase reactions may contribute to the interstellar synthesis of "complex" molecules previously thought to form exclusively via UV photons.

Non-enzymatic synthesis of the coenzymes, uridine diphosphate glucose and cytidine diphosphate choline, and other phosphorylated metabolic intermediates

NASA Technical Reports Server (NTRS)

Mar, A.; Dworkin, J.; Oro, J.

1987-01-01

Using urea and cyanamide, the two condensing agents considered to have been present on the primitive earth, uridine diphosphate glucose (UDPG), cytidine diphosphate choline (CDP-choline), glucose-1-phosphate (G1P), and glucose-6-phosphate (G6P) were synthesized under simulated prebiotic conditions. The reaction products were separated and identified using paper chromatography, thin layer chromatography, enzymatic analyses, and ion-pair reverse-phase high performance liquid chromatography. The possibility of nonenzymatic synthesis of metabolic intermediates on the primitive earth from simple precursors was thus demonstrated.

Is Boron a Prebiotic Element? A Mini-review of the Essentiality of Boron for the Appearance of Life on Earth

NASA Astrophysics Data System (ADS)

Scorei, Romulus

2012-02-01

Boron is probably a prebiotic element with special importance in the so-called "sugars world". Boron is not present on Earth in its elemental form. It is found only in compounds, e.g., borax, boric acid, kernite, ulexite, colemanite and other borates. Volcanic spring waters sometimes contain boron-based acids (e.g., boric, metaboric, tetraboric and pyroboric acid). Borates influence the formation of ribofuranose from formaldehyde that feeds the "prebiotic metabolic cycle". The importance of boron in the living world is strongly related to its implications in the prebiotic origins of genetic material; consequently, we believe that throughout the evolution of life, the primary role of boron has been to provide thermal and chemical stability in hostile environments. The complexation of boric acid and borates with organic cis-diols remains the most probable chemical mechanism for the role of this element in the evolution of the living world. Because borates can stabilize ribose and form borate ester nucleotides, boron may have provided an essential contribution to the "pre-RNA world".

The Prevailing Catalytic Role of Meteorites in Formamide Prebiotic Processes.

PubMed

Saladino, Raffaele; Botta, Lorenzo; Di Mauro, Ernesto

2018-02-22

Meteorites are consensually considered to be involved in the origin of life on this Planet for several functions and at different levels: (i) as providers of impact energy during their passage through the atmosphere; (ii) as agents of geodynamics, intended both as starters of the Earth's tectonics and as activators of local hydrothermal systems upon their fall; (iii) as sources of organic materials, at varying levels of limited complexity; and (iv) as catalysts. The consensus about the relevance of these functions differs. We focus on the catalytic activities of the various types of meteorites in reactions relevant for prebiotic chemistry. Formamide was selected as the chemical precursor and various sources of energy were analyzed. The results show that all the meteorites and all the different energy sources tested actively afford complex mixtures of biologically-relevant compounds, indicating the robustness of the formamide-based prebiotic chemistry involved. Although in some cases the yields of products are quite small, the diversity of the detected compounds of biochemical significance underlines the prebiotic importance of meteorite-catalyzed condensation of formamide.

Phosphorus: a Case for Mineral-Organic Reactions in Prebiotic Chemistry

NASA Astrophysics Data System (ADS)

Pasek, Matthew; Herschy, Barry; Kee, Terence P.

2015-06-01

The ubiquity of phosphorus (P) in modern biochemistry suggests that P may have participated in prebiotic chemistry prior to the emergence of life. Of the major biogenic elements, phosphorus alone lacks a substantial volatile phase and its ultimate source therefore had to have been a mineral. However, as most native P minerals are chemically un-reactive within the temperature-pressure-pH regimes of contemporary life, it begs the question as to whether the most primitive early living systems on earth had access to a more chemically reactive P-mineral inventory. The meteoritic mineral schreibersite has been proposed as an important source of reactive P on the early earth. The chemistry of schreibersite as a P source is summarized and reviewed here. Recent work has also shown that reduced oxidation state P compounds were present on the early earth; these compounds lend credence to the relevance of schreibersite as a prebiotic mineral. Ultimately, schreibersite will oxidize to phosphate, but several high-energy P intermediates may have provided the reactive material necessary for incorporating P into prebiotic molecules.

Prebiotic materials from on and off the early Earth

NASA Technical Reports Server (NTRS)

Bernstein, Max

2006-01-01

One of the great puzzles of all time is how did life arise? It has been universally presumed that life arose in a soup rich in compounds made mostly of carbon, the kind of which we are currently composed. Where did these organic molecules come from? In this talk I will review proposed contributions to pre-biotic organic chemistry from both terrestrial processes (i.e., hydrothermal vents, Miller-Urey syntheses) and also from space. While the former is perhaps better known and more commonly taught in school, we now know that comet and asteroid dust deliver tons of organics to the Earth every day, and there is a growing consensus among scientists that molecules from space played an important role in making the Earth habitable, and perhaps even provided specific compounds that were directly related to the origin of life.

The diffuse interstellar bands: a tracer for organics in the diffuse interstellar medium?

NASA Technical Reports Server (NTRS)

Salama, F.

1998-01-01

The diffuse interstellar bands (DIBs) are absorption bands seen in the spectra of stars obscured by interstellar dust. DIBs are recognized as a tracer for free, organic molecules in the diffuse interstellar medium (ISM). The potential molecular carriers for the DIBs are discussed with an emphasis on neutral and ionized polycyclic aromatic hydrocarbons (PAHs) for which the most focused effort has been made to date. From the combined astronomical, laboratory and theoretical study, it is concluded that a distribution of free neutral and ionized complex organics (PAHs, fullerenes, unsaturated hydrocarbons) represents the most promising class of candidates to account for the DIBs. The case for aromatic hydrocarbons appears particularly strong. The implied widespread distribution of complex organics in the diffuse ISM bears profound implications for our understanding of the chemical complexity of the ISM, the evolution of prebiotic molecules and its impact on the origin and the evolution of life on early Earth through the exogenous delivery (cometary encounters and metoritic bombardments) of prebiotic organics.

Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites

PubMed Central

Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

2011-01-01

Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a “one pot” suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using 13C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems. PMID:21825143

Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites.

PubMed

Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

2011-08-23

Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a "one pot" suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using (13)C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems.

Probiotics, Prebiotics, and Synbiotics for the Prevention of Necrotizing Enterocolitis.

PubMed

Johnson-Henry, Kathene C; Abrahamsson, Thomas R; Wu, Richard You; Sherman, Philip M

2016-09-01

Necrotizing enterocolitis (NEC) is a devastating intestinal disease in preterm infants characterized by barrier disruption, intestinal microbial dysbiosis, and persistent inflammation of the colon, which results in high mortality rates. Current strategies used to manage this disease are not sufficient, although the use of human breast milk reduces the risk of NEC. Mother's milk is regarded as a fundamental nutritional source for neonates, but pasteurization of donor breast milk affects the composition of bioactive compounds. Current research is evaluating the benefits and potential pitfalls of adding probiotics and prebiotics to pasteurized milk so as to improve the functionality of the milk and thereby reduce the burden of illness caused by NEC. Probiotics (live micro-organisms that confer health to the host) and prebiotics (nondigestible oligosaccharides that stimulate the growth of healthy bacteria) are functional foods known to mediate immune responses and modulate microbial populations in the gut. Clinical research shows strain- and compound-specific responses when probiotics or prebiotics are administered in conjunction with donor breast milk for the prevention of NEC. Despite ongoing controversy surrounding optimal treatment strategies, randomized controlled studies are now investigating the use of synbiotics to reduce the incidence and severity of NEC. Synbiotics, a combination of probiotics and prebiotics, have been proposed to enhance beneficial health effects in the intestinal tract more than either agent administered alone. This review considers the implications of using probiotic-, prebiotic-, and synbiotic-supplemented breast milk as a strategy to prevent NEC and issues that could be encountered with the preparations. © 2016 American Society for Nutrition.

Probiotics, Prebiotics, and Synbiotics for the Prevention of Necrotizing Enterocolitis12

PubMed Central

Wu, Richard You

2016-01-01

Necrotizing enterocolitis (NEC) is a devastating intestinal disease in preterm infants characterized by barrier disruption, intestinal microbial dysbiosis, and persistent inflammation of the colon, which results in high mortality rates. Current strategies used to manage this disease are not sufficient, although the use of human breast milk reduces the risk of NEC. Mother’s milk is regarded as a fundamental nutritional source for neonates, but pasteurization of donor breast milk affects the composition of bioactive compounds. Current research is evaluating the benefits and potential pitfalls of adding probiotics and prebiotics to pasteurized milk so as to improve the functionality of the milk and thereby reduce the burden of illness caused by NEC. Probiotics (live micro-organisms that confer health to the host) and prebiotics (nondigestible oligosaccharides that stimulate the growth of healthy bacteria) are functional foods known to mediate immune responses and modulate microbial populations in the gut. Clinical research shows strain- and compound-specific responses when probiotics or prebiotics are administered in conjunction with donor breast milk for the prevention of NEC. Despite ongoing controversy surrounding optimal treatment strategies, randomized controlled studies are now investigating the use of synbiotics to reduce the incidence and severity of NEC. Synbiotics, a combination of probiotics and prebiotics, have been proposed to enhance beneficial health effects in the intestinal tract more than either agent administered alone. This review considers the implications of using probiotic-, prebiotic-, and synbiotic-supplemented breast milk as a strategy to prevent NEC and issues that could be encountered with the preparations. PMID:27633108

Prebiotic chemistry: chemical evolution of organics on the primitive Earth under simulated prebiotic conditions.

PubMed

Dondi, Daniele; Merli, Daniele; Pretali, Luca; Fagnoni, Maurizio; Albini, Angelo; Serpone, Nick

2007-11-01

A series of prebiotic mixtures of simple molecules, sources of C, H, N, and O, were examined under conditions that may have prevailed during the Hadean eon (4.6-3.8 billion years), namely an oxygen-free atmosphere and a significant UV radiation flux over a large wavelength range due to the absence of an ozone layer. Mixtures contained a C source (methanol, acetone or other ketones), a N source (ammonia or methylamine), and an O source (water) at various molar ratios of C : H : N : O. When subjected to UV light or heated for periods of 7 to 45 days under an argon atmosphere, they yielded a narrow product distribution of a few principal compounds. Different initial conditions produced different distributions. The nature of the products was ascertained by gas chromatographic-mass spectral analysis (GC-MS). UVC irradiation of an aqueous methanol-ammonia-water prebiotic mixture for 14 days under low UV dose (6 x 10(-2) Einstein) produced methylisourea, hexamethylenetetramine (HMT), methyl-HMT and hydroxy-HMT, whereas under high UV dose (45 days; 1.9 x 10(-1) Einstein) yielded only HMT. By contrast, the prebiotic mixture composed of acetone-ammonia-water produced five principal species with acetamide as the major component; thermally the same mixture produced a different product distribution of four principal species. UVC irradiation of the CH(3)CN-NH(3)-H(2)O prebiotic mixture for 7 days gave mostly trimethyl-s-triazine, whereas in the presence of two metal oxides (TiO(2) or Fe(2)O(3)) also produced some HMT; the thermal process yielded only acetamide.

Subsumed complexity: abiogenesis as a by-product of complex energy transduction.

PubMed

Adam, Z R; Zubarev, D; Aono, M; Cleaves, H James

2017-12-28

The origins of life bring into stark relief the inadequacy of our current synthesis of thermodynamic, chemical, physical and information theory to predict the conditions under which complex, living states of organic matter can arise. Origins research has traditionally proceeded under an array of implicit or explicit guiding principles in lieu of a universal formalism for abiogenesis. Within the framework of a new guiding principle for prebiotic chemistry called subsumed complexity , organic compounds are viewed as by-products of energy transduction phenomena at different scales (subatomic, atomic, molecular and polymeric) that retain energy in the form of bonds that inhibit energy from reaching the ground state. There is evidence for an emergent level of complexity that is overlooked in most conceptualizations of abiogenesis that arises from populations of compounds formed from atomic energy input. We posit that different forms of energy input can exhibit different degrees of dissipation complexity within an identical chemical medium. By extension, the maximum capacity for organic chemical complexification across molecular and macromolecular scales subsumes, rather than emerges from, the underlying complexity of energy transduction processes that drive their production and modification.This article is part of the themed issue 'Reconceptualizing the origins of life'. © 2017 The Author(s).

Subsumed complexity: abiogenesis as a by-product of complex energy transduction

NASA Astrophysics Data System (ADS)

Adam, Z. R.; Zubarev, D.; Aono, M.; Cleaves, H. James

2017-11-01

The origins of life bring into stark relief the inadequacy of our current synthesis of thermodynamic, chemical, physical and information theory to predict the conditions under which complex, living states of organic matter can arise. Origins research has traditionally proceeded under an array of implicit or explicit guiding principles in lieu of a universal formalism for abiogenesis. Within the framework of a new guiding principle for prebiotic chemistry called subsumed complexity, organic compounds are viewed as by-products of energy transduction phenomena at different scales (subatomic, atomic, molecular and polymeric) that retain energy in the form of bonds that inhibit energy from reaching the ground state. There is evidence for an emergent level of complexity that is overlooked in most conceptualizations of abiogenesis that arises from populations of compounds formed from atomic energy input. We posit that different forms of energy input can exhibit different degrees of dissipation complexity within an identical chemical medium. By extension, the maximum capacity for organic chemical complexification across molecular and macromolecular scales subsumes, rather than emerges from, the underlying complexity of energy transduction processes that drive their production and modification. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Application of the Mars Organic Analyzer to nucleobase and amine biomarker detection.

PubMed

Skelley, Alison M; Cleaves, H James; Jayarajah, Christine N; Bada, Jeffrey L; Mathies, Richard A

2006-12-01

The Mars Organic Analyzer (MOA), a portable microfabricated capillary electrophoresis instrument being developed for planetary exploration, is used to analyze a wide variety of fluorescamine-labeled amine-containing biomarker compounds, including amino acids, mono and diaminoalkanes, amino sugars, nucleobases, and nucleobase degradation products. The nucleobases cytosine and adenine, which contain an exocyclic primary amine, were effectively labeled, separated, and detected at concentrations <500 nM. To test the general applicability of the MOA for biomarker detection, amino acids and mono- and diamines were extracted from bacterial cells using both hydrolysis and sublimation followed by analysis. The extrapolated limit of detection provided by the valine biomarker was approximately 4 x 10(3) cells per sample. Products of an NH(4)CN polymerization that simulate a prebiotic synthesis were also successfully isolated via sublimation and analyzed. Adenine and alanine/serine were detected with no additional sample cleanup at 120 +/- 13 microM and 4.1 +/- 1 microM, respectively, corresponding to a reaction yield of 0.04% and 0.0003%, respectively. This study demonstrates that the MOA provides sensitive detection and analysis of low levels of a wide variety of amine-containing organic compounds from both biological and abiotic sources.

Integrated Microchemical Analysis System Using DS2 Penetrator Technology for the Enantiomeric Detection of Amino Acids

NASA Technical Reports Server (NTRS)

Grunthaner, Frank J.; Bada, Jeffrey L.; Mathies, Richard; Hutt, Lester; Grunthaner, Paula; Grannan, Sabrina; Lin, Gisela; Blaney, Diana L.; McDonald, Gene; Becker, Luann

1996-01-01

Any strategy for investigating whether abiotic and/or biotic organic molecules are present on Mars and the search for biosignatures should focus on compounds which are readily synthesized under plausible prebiotic conditions, play an essential role in biochemistry as we know it and have properties such as chirality (handedness) which can be used to distinguish between abiotic vs. biotic origins (1). Amino acids are one of the few compound classes that fulfill all these requirements. They are synthesized in high yields in prebiotic simulation experiments, are one of the more abundant types of organic compounds present in carbonaceous meteorites and only the L-enantiomers are used in the proteins and enzymes in life on Earth.

Exploring the Fate of Nitrogen Heterocycles in Complex Prebiotic Mixtures

NASA Technical Reports Server (NTRS)

Smith, Karen E.; Callahan, Michael P.; Cleaves, Henderson J.; Dworkin, Jason P.; House, Christopher H.

2011-01-01

A long standing question in the field of prebiotic chemistry is the origin of the genetic macromolecules DNA and RNA. DNA and RNA have very complex structures with repeating subunits of nucleotides, which are composed of nucleobases (nitrogen heterocycles) connected to sugar-phosphate. Due to the instability of some nucleobases (e.g. cytosine), difficulty of synthesis and instability of D-ribose, and the likely scarcity of polyphosphates necessary for the modern nucleotides, alternative nucleotides have been proposed for constructing the first genetic material. Thus, we have begun to investigate the chemistry of nitrogen heterocycles in plausible, complex prebiotic mixtures in an effort to identify robust reactions and potential alternative nucleotides. We have taken a complex prebiotic mixture produced by a spark discharge acting on a gas mixture of N2, CO2, CH4, and H2, and reacted it with four nitrogen heterocycles: uracil, 5-hydroxymethyluracil, guanine, and isoxanthopterin (2-amino-4,7-dihydroxypteridine). The products of the reaction between the spark mixture and each nitrogen heterocycle were characterized by liquid chromatography coupled to UV spectroscopy and Orbitrap mass spectrometry. We found that the reaction between the spark mixtUl'e and isoxanthopterin formed one major product, which was a cyanide adduct. 5-hydroxymethyluracil also reacted with the spark mixture to form a cyanide adduct, uracil-5-acetonitrile, which has been synthesized previously by reacting HCN with S-hydroxymethyluracil. Unlike isoxanthopterin, the chromatogram of the 5-hydroxymethyluracil reaction was much more complex with multiple products including spark-modified dimers. Additionally, we observed that HMU readily self-polymerizes in solution to a variety of oligomers consistent with those suggested by Cleaves. Guanine and uracil, the biological nucleobases, did not react with the spark mixture, even at high temperature (100 C). This suggests that there are alternative nucleobases which are more reactive under prebiotic conditions and may have been involved in producing precursor nucleotides.

Laboratory Studies of Methane and Its Relationship to Prebiotic Chemistry

NASA Astrophysics Data System (ADS)

Kobayashi, Kensei; Geppert, Wolf D.; Carrasco, Nathalie; Holm, Nils G.; Mousis, Olivier; Palumbo, Maria Elisabetta; Waite, J. Hunter; Watanabe, Naoki; Ziurys, Lucy M.

2017-08-01

To examine how prebiotic chemical evolution took place on Earth prior to the emergence of life, laboratory experiments have been conducted since the 1950s. Methane has been one of the key molecules in these investigations. In earlier studies, strongly reducing gas mixtures containing methane and ammonia were used to simulate possible reactions in the primitive atmosphere of Earth, producing amino acids and other organic compounds. Since Earth's early atmosphere is now considered to be less reducing, the contribution of extraterrestrial organics to chemical evolution has taken on an important role. Such organic molecules may have come from molecular clouds and regions of star formation that created protoplanetary disks, planets, asteroids, and comets. The interstellar origin of organics has been examined both experimentally and theoretically, including laboratory investigations that simulate interstellar molecular reactions. Endogenous and exogenous organics could also have been supplied to the primitive ocean, making submarine hydrothermal systems plausible sites of the generation of life. Experiments that simulate such hydrothermal systems where methane played an important role have consequently been conducted. Processes that occur in other Solar System bodies offer clues to the prebiotic chemistry of Earth. Titan and other icy bodies, where methane plays significant roles, are especially good targets. In the case of Titan, methane is both in the atmosphere and in liquidospheres that are composed of methane and other hydrocarbons, and these have been studied in simulation experiments. Here, we review the wide range of experimental work in which these various terrestrial and extraterrestrial environments have been modeled, and we examine the possible role of methane in chemical evolution.

Synthesis of Prebiotic Caramels Catalyzed by Ion-Exchange Resin Particles: Kinetic Model for the Formation of Di-d-fructose Dianhydrides.

PubMed

Ortiz Cerda, Imelda-Elizabeth; Thammavong, Phahath; Caqueret, Vincent; Porte, Catherine; Mabille, Isabelle; Garcia Fernandez, José Manuel; Moscosa Santillan, Mario; Havet, Jean-Louis

2018-02-21

Caramel enriched in di-d-fructose dianhydrides (DFAs, a family of prebiotic cyclic fructodisaccharides) is a functional food with beneficial properties for health. The aim of this work was to study the conversion of fructose into DFAs catalyzed by acid ion-exchange resin, in order to establish a simplified mechanism of the caramelization reaction and a kinetic model for DFA formation. Batch reactor experiments were carried out in a 250 mL spherical glass flask and afforded up to 50% DFA yields. The mechanism proposed entails order 2 reactions that describe fructose conversion on DFAs or formation of byproducts such as HMF or melanoidines. A third order 1 reaction defines DFA transformation into fructosyl-DFAs or fructo-oligosaccharides. The influence of fructose concentration, resin loading and temperature was studied to calculate the kinetic parameters necessary to scale up the process.

Prebiotic coordination chemistry: The potential role of transition-metal complexes in the chemical evolution

NASA Technical Reports Server (NTRS)

Beck, M.

1979-01-01

In approaching the extremely involved and complex problem of the origin of life, consideration of the coordination chemistry appeared not only as a possibility but as a necessity. The first model experiments appear to be promising because of prebiotic-type synthesis by means of transition-metal complexes. It is especially significant that in some instances various types of vitally important substances (nucleic bases, amino acids) are formed simultaneously. There is ground to hope that systematic studies in this field will clarify the role of transition-metal complexes in the organizatorial phase of chemical evolution. It is obvious that researchers working in the fields of the chemistry of cyano and carbonyl complexes, and of the catalytic effect of transition-metal complexes are best suited to study these aspects of the attractive and interesting problem of the origin of life.

Prebiotic Polymerization: Oxidative Polymerization of 2,3 Dimercapto-1- Propanol on the Surface of Iron(III) Hydroxide Oxide

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1995-01-01

The oxidation of 2,3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers. This polymerization occurred readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 micromole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the FE(OH)O phase. Reactions carried out at the same ratio of dithiol to FE(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis is discussed.

Prebiotic polymerization: Oxidative polymerization of 2, 3-dimercapto-1-propanol on the surface of iron(III) hydroxide oxide

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1995-01-01

The oxidation of 2, 3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers. This polymerization occurred readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 micromole Fe) for 3 days under anaerobic conditions at 40 C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the Fe(OH)O phase. Reactions carried out at the same ratio of dithiol to Fe(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis is discussed.

Chemomimesis and Molecular Darwinism in Action: From Abiotic Generation of Nucleobases to Nucleosides and RNA.

PubMed

Saladino, Raffaele; Šponer, Judit E; Šponer, Jiří; Costanzo, Giovanna; Pino, Samanta; Di Mauro, Ernesto

2018-06-20

Molecular Darwinian evolution is an intrinsic property of reacting pools of molecules resulting in the adaptation of the system to changing conditions. It has no a priori aim. From the point of view of the origin of life, Darwinian selection behavior, when spontaneously emerging in the ensembles of molecules composing prebiotic pools, initiates subsequent evolution of increasingly complex and innovative chemical information. On the conservation side, it is a posteriori observed that numerous biological processes are based on prebiotically promptly made compounds, as proposed by the concept of Chemomimesis. Molecular Darwinian evolution and Chemomimesis are principles acting in balanced cooperation in the frame of Systems Chemistry. The one-pot synthesis of nucleosides in radical chemistry conditions is possibly a telling example of the operation of these principles. Other indications of similar cases of molecular evolution can be found among biogenic processes.

A redox beginning: Which came first phosphoryl, acyl, or electron transfer ?. [Abstract only

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1994-01-01

Thermodynamic and kinetic information available on the synthesis of prebiotic monomers and polymers will be examined in order to illuminate the prebiotic plausibility of polymer syntheses based on (a) phosphoryl transfer that yields phosphodiester polymers, (b) acyl transfer that gives polyamides, and (c) electron transfer that produces polydisulfide or poly(thio)ester polymers. New experimental results on the oxidative polymerization of 2,3-dimercaptopropanol by ferric ions on the surface of ferric hydroxide oxide will be discussed as a chemical model of polymerization by electron transfer. This redox polymerization that yields polymers with a polydisulfide backbone was found to give oligomers up to the 15-mer from 1 mM of 2,3-dimercaptopropanol after one day at 25 C. High pressure liquid chromatography (HPLC) analysis of the oligomers was carried out on an Alltech OH-100 column eluted with acetonitrile-water.

Clays as possible catalysts for peptide formation in the prebiotic era

NASA Technical Reports Server (NTRS)

Paecht-Horowitz, M.

1976-01-01

From the point of view of prebiotic synthesis, clays might have performed functions of concentration, catalysis, and protection of molecules. The degrees of polymerization obtained, when amino acid adenylates are added to montmorillonite suspensions in water, are much higher than those obtained by polymerization in the absence of such a clay. In addition, they are of a discrete spectrum, usually multiples of 6 or 7, and reach values of up to 40 mers. In the absence of clay a continuous spectrum of degrees of polymerization is obtained, and usually up to 4-6 mers only. Copolymerization in the absence of clays yields mostly random copolymers, in their presence mostly block copolymers are obtained. Optical density measurements show that after adsorption has taken place on the clay, stacking of its layers occurs. Polymerization starts only after these stacked layers have been formed

Prebiotic-like chemistry on Titan.

PubMed

Raulin, François; Brassé, Coralie; Poch, Olivier; Coll, Patrice

2012-08-21

Titan, the largest satellite of Saturn, is the only one in the solar system with a dense atmosphere. Mainly composed of dinitrogen with several % of methane, this atmosphere experiences complex organic processes, both in the gas and aerosol phases, which are of prebiotic interest and within an environment of astrobiological interest. This tutorial review presents the different approaches which can be followed to study such an exotic place and its chemistry: observation, theoretical modeling and experimental simulation. It describes the Cassini-Huygens mission, as an example of observational tools, and gives the new astrobiologically oriented vision of Titan which is now available by coupling the three approaches. This includes the many analogies between Titan and the Earth, in spite of the much lower temperature in the Saturn system, the complex organic chemistry in the atmosphere, from the gas to the aerosol phases, but also the potential organic chemistry on Titan's surface, and in its possible internal water ocean.

Gut microbiota manipulation with prebiotics in patients with non-alcoholic fatty liver disease: a randomized controlled trial protocol.

PubMed

Lambert, Jennifer E; Parnell, Jill A; Eksteen, Bertus; Raman, Maitreyi; Bomhof, Marc R; Rioux, Kevin P; Madsen, Karen L; Reimer, Raylene A

2015-12-03

Evidence for the role of the gut microbiome in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) is emerging. Strategies to manipulate the gut microbiota towards a healthier community structure are actively being investigated. Based on their ability to favorably modulate the gut microbiota, prebiotics may provide an inexpensive yet effective dietary treatment for NAFLD. Additionally, prebiotics have established benefits for glucose control and potentially weight control, both advantageous in managing fatty liver disease. Our objective is to evaluate the effects of prebiotic supplementation, adjunct to those achieved with diet-induced weight loss, on heptic injury and liver fat, the gut microbiota, inflammation, glucose tolerance, and satiety in patients with NAFLD. In a double blind, placebo controlled, parallel group study, adults (BMI ≥25) with confirmed NAFLD will be randomized to either a 16 g/d prebiotic supplemented group or isocaloric placebo group for 24 weeks (n = 30/group). All participants will receive individualized dietary counseling sessions with a registered dietitian to achieve 10 % weight loss. Primary outcome measures include change in hepatic injury (fibrosis and inflammation) and liver fat. Secondary outcomes include change in body composition, appetite and dietary adherence, glycemic and insulinemic responses and inflammatory cytokines. Mechanisms related to prebiotic-induced changes in gut microbiota (shot-gun sequencing) and their metabolic by-products (volatile organic compounds) and de novo lipogenesis (using deuterium incorporation) will also be investigated. There are currently no medications or surgical procedures approved for the treatment of NAFLD and weight loss via lifestyle modification remains the cornerstone of current care recommendations. Given that prebiotics target multiple metabolic impairments associated with NAFLD, investigating their ability to modulate the gut microbiota and hepatic health in patients with NAFLD is warranted. ClinicalTrials.gov (NCT02568605) Registered 30 September 2015.

Human Milk Oligosaccharides (HMOS): Structure, Function, and Enzyme-Catalyzed Synthesis.

PubMed

Chen, Xi

2015-01-01

The important roles played by human milk oligosaccharides (HMOS), the third major component of human milk, in the health of breast-fed infants have been increasingly recognized, as the structures of more than 100 different HMOS have now been elucidated. Despite the recognition of the various functions of HMOS as prebiotics, antiadhesive antimicrobials, and immunomodulators, the roles and the applications of individual HMOS species are less clear. This is mainly due to the limited accessibility to large amounts of individual HMOS in their pure forms. Current advances in the development of enzymatic, chemoenzymatic, whole-cell, and living-cell systems allow for the production of a growing number of HMOS in increasing amounts. This effort will greatly facilitate the elucidation of the important roles of HMOS and allow exploration into the applications of HMOS both as individual compounds and as mixtures of defined structures with desired functions. The structures, functions, and enzyme-catalyzed synthesis of HMOS are briefly surveyed to provide a general picture about the current progress on these aspects. Future efforts should be devoted to elucidating the structures of more complex HMOS, synthesizing more complex HMOS including those with branched structures, and developing HMOS-based or HMOS-inspired prebiotics, additives, and therapeutics. © 2015 Elsevier Inc. All rights reserved.

Peptide nucleic acids rather than RNA may have been the first genetic molecule

NASA Technical Reports Server (NTRS)

Nelson, K. E.; Levy, M.; Miller, S. L.

2000-01-01

Numerous problems exist with the current thinking of RNA as the first genetic material. No plausible prebiotic processes have yet been demonstrated to produce the nucleosides or nucleotides or for efficient two-way nonenzymatic replication. Peptide nucleic acid (PNA) is a promising precursor to RNA, consisting of N-(2-aminoethyl)glycine (AEG) and the adenine, uracil, guanine, and cytosine-N-acetic acids. However, PNA has not yet been demonstrated to be prebiotic. We show here that AEG is produced directly in electric discharge reactions from CH(4), N(2), NH(3), and H(2)O. Electric discharges also produce ethylenediamine, as do NH(4)CN polymerizations. AEG is produced from the robust Strecker synthesis with ethylenediamine. The NH(4)CN polymerization in the presence of glycine leads to the adenine and guanine-N(9)-acetic acids, and the cytosine and uracil-N(1)-acetic acids are produced in high yield from the reaction of cyanoacetaldehyde with hydantoic acid, rather than urea. Preliminary experiments suggest that AEG may polymerize rapidly at 100 degrees C to give the polypeptide backbone of PNA. The ease of synthesis of the components of PNA and possibility of polymerization of AEG reinforce the possibility that PNA may have been the first genetic material.

Prebiotic synthesis of carboxylic acids, amino acids and nucleic acid bases from formamide under photochemical conditions⋆

NASA Astrophysics Data System (ADS)

Botta, Lorenzo; Mattia Bizzarri, Bruno; Piccinino, Davide; Fornaro, Teresa; Robert Brucato, John; Saladino, Raffaele

2017-07-01

The photochemical transformation of formamide in the presence of a mixture of TiO2 and ZnO metal oxides as catalysts afforded a large panel of molecules of biological relevance, including carboxylic acids, amino acids and nucleic acid bases. The reaction was less effective when performed in the presence of only one mineral, highlighting the role of synergic effects between the photoactive catalysts. Taken together, these results suggest that the synthesis of chemical precursors for both the genetic and the metabolic apparatuses might have occurred in a simple environment, consisting of formamide, photoactive metal oxides and UV-radiation.

The Metabolic World: Sugars as an Energized Carbon Substrate for Prebiotic and Biotic Synthesis

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1996-01-01

To understand the origin of metabolism and biopolymer synthesis we investigated the energy sources that drive anabolic metabolism. We found that biosynthesis of amino acids and lipids from sugars is driven bz the free energy of redox disproportionation of carbon (see discussion or next page). The indispensable role of sugar disproportionation in the biosynthesis of amino acids and lipids suggests that the origin of life uses the same chemical engine, and was therefore based on nonenzymatic redox disproportionation reactions of sugars that occurred in the presence o ammonia and hydrogen sulfide. The chemistry of this 'metabolic' model of the origin of life is described.

The origin and emergence of life under impact bombardment.

PubMed

Cockell, Charles S

2006-10-29

Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's 'warm little pond'. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology-generating large numbers of 'experiments' in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities.

Ribonucleotides.

PubMed

Sutherland, John D

2010-04-01

It has normally been assumed that ribonucleotides arose on the early Earth through a process in which ribose, the nucleobases, and phosphate became conjoined. However, under plausible prebiotic conditions, condensation of nucleobases with ribose to give beta-ribonucleosides is fraught with difficulties. The reaction with purine nucleobases is low-yielding and the reaction with the canonical pyrimidine nucleobases does not work at all. The reasons for these difficulties are considered and an alternative high-yielding synthesis of pyrimidine nucleotides is discussed. Fitting the new synthesis to a plausible geochemical scenario is a remaining challenge but the prospects appear good. Discovery of an improved method of purine synthesis, and an efficient means of stringing activated nucleotides together, will provide underpinning support to those theories that posit a central role for RNA in the origins of life.

Question 2: why an astrobiological study of titan will help us understand the origin of life.

PubMed

Raulin, Francois

2007-10-01

For understanding the origin(s) of life on Earth it is essential to search for and study extraterrestrial environments where some of the processes which participated in the emergence of Life on our planet are still occurring. This is one of the goals of astrobiology. In that frame, the study of extraterrestrial organic matter is essential and is certainly not of limited interest regarding prebiotic molecular evolution. Titan, the largest satellite of Saturn and the only planetary body with an atmosphere similar to that of the Earth is one of the places of prime interest for these astrobiological questions. It presents many analogies with the primitive Earth, and is a prebiotic-like laboratory at the planetary scale, where a complex organic chemistry in is currently going on.

Energy yields in the prebiotic synthesis of hydrogen cyanide and formaldehyde

NASA Technical Reports Server (NTRS)

Stribling, R.; Miller, S. L.

1986-01-01

Prebiotic experiments are usually reported in terms of carbon yields, i.e., the yield of product based on the total carbon in the system. These experiments usually involve a large input of energy and are designed to maximize the yields of product. However, large inputs of energy result in multiple activation of the reactants and products. A more realistic prebiotic experiment is to remove the products of the activation step so they are not exposed a second time to the energy source. This is equivalent to transporting the products synthesized in the primitive atmosphere to the ocean, and thereby protecting them from destruction by atmospheric energy sources. Experiments of this type, using lower inputs of energy, give energy yields (moles of products/joule) which can be used to estimate the relative importance of the different energy sources on the primitive earth. Simulated prebiotic atmospheres containing either CH4, CO or CO2 with N2, H2O and variable amounts of H2 were subjected to a high frequency Tesla coil. Samples of the aqueous phase were taken at various time intervals from 1 hr to 7 days, and the energy yields were obtained by extrapolation to zero time. The samples were analyzed for HCN with the cyanide electrode and for H2CO by chromotropic acid. The spark energy was estimated by calorimetry. The temperature rise in an insulated discharge flask was compared with the temperature rise from a resistance heater in the same flask. These results will be compared with calculated production rates of HCN and H2CO from lightning and a number of photochemical processes on the primitive Earth.

Laboratory Studies of Methane and Its Relationship to Prebiotic Chemistry.

PubMed

Kobayashi, Kensei; Geppert, Wolf D; Carrasco, Nathalie; Holm, Nils G; Mousis, Olivier; Palumbo, Maria Elisabetta; Waite, J Hunter; Watanabe, Naoki; Ziurys, Lucy M

2017-08-01

To examine how prebiotic chemical evolution took place on Earth prior to the emergence of life, laboratory experiments have been conducted since the 1950s. Methane has been one of the key molecules in these investigations. In earlier studies, strongly reducing gas mixtures containing methane and ammonia were used to simulate possible reactions in the primitive atmosphere of Earth, producing amino acids and other organic compounds. Since Earth's early atmosphere is now considered to be less reducing, the contribution of extraterrestrial organics to chemical evolution has taken on an important role. Such organic molecules may have come from molecular clouds and regions of star formation that created protoplanetary disks, planets, asteroids, and comets. The interstellar origin of organics has been examined both experimentally and theoretically, including laboratory investigations that simulate interstellar molecular reactions. Endogenous and exogenous organics could also have been supplied to the primitive ocean, making submarine hydrothermal systems plausible sites of the generation of life. Experiments that simulate such hydrothermal systems where methane played an important role have consequently been conducted. Processes that occur in other Solar System bodies offer clues to the prebiotic chemistry of Earth. Titan and other icy bodies, where methane plays significant roles, are especially good targets. In the case of Titan, methane is both in the atmosphere and in liquidospheres that are composed of methane and other hydrocarbons, and these have been studied in simulation experiments. Here, we review the wide range of experimental work in which these various terrestrial and extraterrestrial environments have been modeled, and we examine the possible role of methane in chemical evolution. Key Words: Methane-Interstellar environments-Submarine hydrothermal systems-Titan-Origin of life. Astrobiology 17, 786-812.

Synthesis of RNA oligomers on heterogeneous templates

NASA Technical Reports Server (NTRS)

Ertem, G.; Ferris, J. P.

1996-01-01

The concept of an RNA world in the chemical origin of life is appealing, as nucleic acids are capable of both information storage and acting as templates that catalyse the synthesis of complementary molecules. Template-directed synthesis has been demonstrated for homogeneous oligonucleotides that, like natural nucleic acids, have 3',5' linkages between the nucleotide monomers. But it seems likely that prebiotic routes to RNA-like molecules would have produced heterogeneous molecules with various kinds of phosphodiester linkages and both linear and cyclic nucleotide chains. Here we show that such heterogeneity need be no obstacle to the templating of complementary molecules. Specifically, we show that heterogeneous oligocytidylates, formed by the montmorillonite clay-catalysed condensation of actuated monomers, can serve as templates for the synthesis of oligoguanylates. Furthermore, we show that oligocytidylates that are exclusively 2',5'-linked can also direct synthesis of oligoguanylates. Such heterogeneous templating reactions could have increased the diversity of the pool of protonucleic acids from which life ultimately emerged.

Thunderstorm activity in early Earth: same estimations from point of view a role of electric discharges in formation of prebiotic conditions

NASA Astrophysics Data System (ADS)

Serozhkin, Yu.

2008-09-01

Introduction The structure and the physical parameters of an early Earth atmosphere [1], most likely, played a determining role in formation of conditions for origin of life. The estimation of thunderstorm activity in atmosphere of the early Earth is important for understanding of the real role of electrical discharges during formation of biochemical compounds. The terrestrial lightning a long time are considered as one of components determining a physical state and chemical structure of an atmosphere. Liebig in 1827 has considered a capability of nitrogen fixation at discharges of lightning [2]. Recent investigations (Lamarque et al. 1996) have achieved that production rate of NOx due to lightning at 3·106 ton/year [3]. The efficiency of electric discharges as energy source for synthesis of low molecular weight organic compounds is explained by the several factors. To them concern effect of optical radiation, high temperature, shock waves and that is especially important, pulse character of these effects. The impulse impact is essentially reduced the probability of destruction of the formed compounds. However, for some reasons is not clear the real role of electric discharges in synthesis of biochemical compounds. The discharges used in experiments on synthesis of organic substances, do not remind the discharges observable in a nature. One more aspect of a problem about a role of electric discharges in forming pre-biotic conditions on the Earth is connected with the thunderstorm activity in a modern atmosphere. This activity is connected with the presence in an atmosphere of ice crystals and existing gradient of temperature. To tell something about a degree of thunderstorm activity during the early Earth, i.e. that period, when formed pre-biotic conditions were is very difficult. Astrobiological potential of various discharges First of all the diversity of electric discharges in terrestrial atmosphere (usual lightning, lightning at eruption of volcanoes, discharges in mesosphere - sprites, elves and jets) puts a question about comparison of the potential efficiency of various discharges for the synthesis of biochemical compounds. The efficiency of lightning's discharges and coronal discharge is compared by Chyba and Sagan [4]. Authors do a conclusion about greater efficiency of lightning discharge for synthesis of organic substances. How to estimate efficiency of various types of discharges at synthesis of chemical compounds? It seems that in the absence of full understanding of mechanism of synthesis under effect of discharges it is necessary to begin from an estimation of quantity of substance located in the field of discharge and energy of discharge. However by viewing a role of energy it is necessary to remember, that at discharge of the usual lightning its main part is spent for a heating of the channel up to high temperatures, at which the organic compounds can not be preserved. We are compared the usual lightning, electrical discharges in mesosphere (sprites etc.) and lightning at eruption of volcanoes. In the Table are shown the following data about the basic types of the terrestrial lightning: - quantity of flashes in one year; - volume occupied by discharge (for usual lightning product of cross section of the channel on length of lightning); - quantity of air in this volume; - product quantity of air on number of flashes in one year. From these dates follows that: - the frequency and energy (≈ 5·102 MJ) of usual lightings make their basic candidate for a role of an energy source for synthesis in atmosphere. Terrestrial lightning is played important role at transformation of low-molecular compounds (NOx). - the huge volume and amount of substance in area of sprites give a reason to speak about their large possibilities for synthesis. As to energy, in sprites (≈ 10 MJ) are absent the losses on heating of substance. The efficiency of its using for synthesis will be more, than in usual lightning. At last time numerous theoretical and experimental researches of gas-grain chemistry show that the chemical reactions on boundary gas - ice play a considerable role in changes of evolution of molecular composition of gas-grains mediums [5,6]. Electric discharges in such gas-grain mediums can be not only energy source for synthesis of biochemical compounds. For prebiotic chemistry will have the important consequences that plasma of these discharges will have properties of dusty plasma. First, it is the presence of the charged micron-size particles (0,1…10 μm). These grains can be charged up to values 103-105 elementary charges at sticking of high-energy electrons and ions (≥1eV), which are produced at lightning discharge. In this connection it is expedient at an estimation of efficiency of the electrical discharges to take into account conditions, in which they occur. In the area of the lightning at eruption of volcanoes there is a plenty of ashes, and aerosols. In the area of the usual lightnings there are snowflakes, drops of water and ice crystals. The electrical discharges in mesosphere cannot be considered without an estimation of influence on biochemical processes the submicron ice crystals and aerosols. What is possible to tell about the degree and nature of thunderstorm activity in the early Earth? We can to formulate some questions: - from what moment of time there were conditions for various types of electrical discharges in an atmosphere; - up to what time, and how we can trace existence of lightning. The modern thunderstorm activity is determined by presence of water in an atmosphere and on a surface of the Earth, and also physical properties of the atmosphere (pressure, temperature, gradient of temperature). The chemical structure of an atmosphere plays a role through influence on temperature and gradient of temperatures. For example, the increase of concentration CO2 gives to global warming. On some estimation in modern conditions the climate warms by 3.8 degrees will increase quantity of lightning at 50 % [7]. The examinations of processes of separation of charges in clouds result in a very narrow diapason of temperature and pressure of an atmosphere, at which the separation of charges is possible. It is necessary to tell that the electrostatic charging of thunderstorm clouds not received a satisfactory explanation. One of not explained properties is the formation at the altitude 6 … 8 km at temperature about -15o the negatively charged layer by thickness some hundreds meters. At this altitude at such pressure the water can exist in three phases. In this layer because of interaction of the ice crystals with snow pellets there is a separation of charges. Above this layer there is a so-called charge reverse - a not explained phenomenon causing that the ice crystals are lower this layer are charged positively, and above negatively. The snow pellets are higher this layer is charged positively, and below negatively. Thus negatively charged layer consists of negatively charged ice crystals and snow pellets. Positively charged snow pellets form a charge at the top of a cloud, and positively charged ice crystals form positive charge in the bottom of a cloud. It follows that the dependence of the electrostatic charging of thunderstorm clouds from parameters of atmosphere is extremely difficult to estimate. About influence of pressure it is possible to tell the general words. It is possible to tell that at pressure corresponding to the point of charge reverse (about 250 Torr at the altitude 8 km) usual thunderstorm activity will decrease. It means that if the atmospheric pressure during formation pre-biotic conditions was less than 100 Torr, it is necessary to discuss a role of electrical discharges, which are connected with accumulation of charges on particles (sand storms, tornado) or ashes at eruption of volcano. What tracks of thunderstorm activity it is possible to search in the past? It is know that the cloud - ground lightning frequently tracks in ground, so-called fulgurites, the alloyed fragments of surface, in which has struck the lightning. There are two classes of fulgurites: sand fulgurites and rock fulgurites. Since fulgurites are real glasses, they are very resistant to weathering and are usually well preserved for a long period of time. For this reason they are used as paleoindicator. It would be interesting to study the opportunity of definition of the lightning stroke date. Conclusion First, we must to orient on such conditions in Earth's early atmosphere in which are possible the existence a so-called charge reverse layer. Next, it would be interesting to study the opportunity of definition of the lightning stroke date by fulgurites. At last, our estimations of the role of electrical discharges for synthesis in atmosphere of early Earth we must to do taking into account the presence in atmosphere of dust grains, ice crystals and aerosols. References [1] Kasting James F. Earth's Early Atmosphere. Science, (1993), Vol. 259, 12 February, pp. 920-926 [2] von Liebig, J. Am. Chem. Phys. 38, pp.329-333 (1827) [3] Lamarque et al. 1996 J. Geophys. Res.101, 22955-68 [4] Chyba C., Sagan C. Electrical energy sources for organic synthesis on the early Earth. Orig Life Evol Biosph. 1991;Vol. 21:pp3-17. [5] Allamandola, L.J. and Hudgins, D.M. (2003) From Interstellar Polycyclic Aromatic Hydrocarbons and Ice to Astrobiology. Proceedings of the NATO ASI entitled "Solid State Astrochemistry", V. Pirronello and J. Krelowski (eds.), Kluwer: Dordrecht. [6] Hugh G.M. Hill; Joseph A. Nuth, (2003), The Catalytic Potential of Cosmic Dust: Implications for Prebiotic Chemistry in the Solar Nebula and Other Protoplanetary Systems, Astrobiology, Vol. 3, No. 2, pp.291-304 [7] Colin Price, NATO Advanced Study Institute on Sprites, Elves and Intense Lightning Discharges, Corte in Corsica, July 24-31, 2004

Why Interstellar Ices Can Be Considered As Precursors For Prebiotic Chemistry

NASA Astrophysics Data System (ADS)

Hendecourt, Louis Le Sergeant d.; de Marcellus, Pierre; Meinert, Cornelia; Myrgorodska, Iuliia; Nahon, Laurent; Modica, Paola; Buhse, Thomas; Meierhenrich, Uwe J.

2015-08-01

Interstellar ices made of simple molecules (H2O, CO, CO2, CH3OH, NH3, CH4…) are abundant species observed in molecular clouds where stars and planetary systems form. Since the constitutive elements (H, O, C, N, S, P) are the most cosmically abundant and condensible, they favor the making of ices on grains. In the mantles formed, a rich organic chemistry develops, thanks to the protective nature of the grains. This chemistry leads to a high complexity. Radical chemistry generated by photo/thermo-chemical processes on the surfaces, leaves to the formation of organic residues as those produced in our laboratory using ice templates, and further studied, using methods that pertain mostly to analytical chemistry. The organic material formed may resemble the Soluble Organic Matter observed in pristine meteorites. From numerous amino acids [1], aldehydes and sugars [2] detected in these residues to chiral molecules and enantiomeric excesses produced by Vacuum Ultra-Violet Circularly Polarized Light from synchrotron radiation [3], one might seriously ask whether the chemistry of molecular clouds out of which stars, planetary systems and debris form, may not be seriously considered as the precursor of prebiotic chemistry in a given environment such as the surface of a telluric planet. I will present the general frame of these experiments in relation to the possibillity of feeding of the necessary prebiotic chemistry for the origin of life. Certainly, prebiotic chemistry is very different in itself than astrochemistry but the starting bricks issued from astrochemistry may well be necessary for the possibility of the emergence of life on planets under certain assumptions I will briefly discuss.REFERENCES[1] Meinert, C., Filippi, J.-J., de Marcellus, P., Le Sergeant d’Hendecourt, L. and Meierhenrich, U.J., ChemPlusChem, 77, 186-191 (2012).[2] de Marcellus, P., Meinert, C., Myrgorodska, I., Nahon, L., Buhse, T., Le Sergeantd’Hendecourt, L., Meierhenrich, U.J., PNAS, January 12th, 2015[3] Modica, P., Meinert, C. de Marcellus, Nahon, L., Meierhenrich, U.J., Le Sergeant d’Hendecourt, L. Astrophys.J, 788, 79

Prebiotic chemical evolution in the astrophysical context.

PubMed

Ziurys, L M; Adande, G R; Edwards, J L; Schmidt, D R; Halfen, D T; Woolf, N J

2015-06-01

An ever increasing amount of molecular material is being discovered in the interstellar medium, associated with the birth and death of stars and planetary systems. Radio and millimeter-wave astronomical observations, made possible by high-resolution laboratory spectroscopy, uniquely trace the history of gas-phase molecules with biogenic elements. Using a combination of both disciplines, the full extent of the cycling of molecular matter, from circumstellar ejecta of dying stars - objects which expel large amounts of carbon - to nascent solar systems, has been investigated. Such stellar ejecta have been found to exhibit a rich and varied chemical content. Observations demonstrate that this molecular material is passed onto planetary nebulae, the final phase of stellar evolution. Here the star sheds almost its entire original mass, becoming an ultraviolet-emitting white dwarf. Molecules such as H2CO, HCN, HCO(+), and CCH are present in significant concentrations across the entire age span of such nebulae. These data suggest that gas-phase polyatomic, carbon-containing molecules survive the planetary nebula phase and subsequently are transported into the interstellar medium, seeding the chemistry of diffuse and then dense clouds. The extent of the chemical complexity in dense clouds is unknown, hindered by the high spectral line density. Organic species such as acetamide and methyl amine are present in such objects, and NH2CHO has a wide Galactic distribution. However, organophosphorus compounds have not yet been detected in dense clouds. Based on carbon and nitrogen isotope ratios, molecular material from the ISM appears to become incorporated into solar system planetesimals. It is therefore likely that interstellar synthesis influences prebiotic chemistry on planet surfaces.

Plasma and collision processes of hypervelocity meteorite impact in the prehistory of life

NASA Astrophysics Data System (ADS)

Managadze, G.

2010-07-01

A new concept is proposed, according to which the plasma and collision processes accompanying hypervelocity impacts of meteorites can contribute to the arising of the conditions on early Earth, which are necessary for the appearance of primary forms of living matter. It was shown that the processes necessary for the emergence of living matter could have started in a plasma torch of meteorite impact and have continued in an impact crater in the case of the arising of the simplest life form. It is generally accepted that planets are the optimal place for the origin and evolution of life. In the process of forming the planetary systems the meteorites, space bodies feeding planet growth, appear around stars. In the process of Earth's formation, meteorite sizes ranged from hundreds and thousands of kilometres. These space bodies consisted mostly of the planetesimals and comet nucleus. During acceleration in Earth's gravitational field they reached hypervelocity and, hitting the surface of planet, generated powerful blowouts of hot plasma in the form of a torch. They also created giant-size craters and dense dust clouds. These bodies were composed of all elements needed for the synthesis of organic compounds, with the content of carbon being up to 5%-15%. A new idea of possible synthesis of the complex organic compounds in the hypervelocity impact-generated plasma torch was proposed and experimentally confirmed. A previously unknown and experimentally corroborated feature of the impact-generated plasma torch allowed a new concept of the prehistory of life to be developed. According to this concept the intensive synthesis of complex organic compounds arose during meteoritic bombardment in the first 0.5 billion years at the stage of the planet's formation. This most powerful and destructive action in Earth's history could have played a key role and prepared conditions for the origin of life. In the interstellar gas-dust clouds, the synthesis of simple organic matter could have been explained by an identical process occurring in the plasma torch of hypervelocity collisions between submicron size dust particles. It is assumed that the processes occurred in the highly unbalanced hot plasma simultaneously with the synthesis of simple and complicated organic compounds, thereby ensuring their ordering and assembly. Bona fide experimental evidence presented below indicates that the physical fields generated in the plasma environment in the process of the formation and expansion of the torch meet the main requirements toward “true” local chiral fields. These fields were very likely to be capable to trigger the initial, weak breaking of enantiomer symmetry and determine the “sign” of the asymmetry of the bioorganic world. These fields could have worked as “trapping” fields influencing spontaneous processes occurring in highly overheated and nonequilibrium plasma in the state that is far from the thermodynamical branch of equilibrium and may have contributed to the formation of an environment needed for the synthesis of homochiral molecular structures, which, in turn, were needed for the emergence of the primary forms of living matter. It has been shown experimentally that the plasma-chemical processes in the torch have high catalytic properties and assure the rise of the chemical reaction rates by 10-100 million times. In the process of the plasma flyaway this in turn can assure the fast formation of simple and complicated organic compounds, including hyper-branched polymers. It is possible to assume that predominantly inorganic substances from meteorites were used for the synthesis of complicated organic compounds on early Earth. A laboratory experiment with hypervelocity impact plasma torch modelling by a laser with a Q-switch mode has shown the possibility of high-molecular organic compound synthesis, with mass of approximately 5000 a.m.u. by meteorite impact with an effective diameter of 100 mkm. The target contained only H, C, N and O elements in inorganic forms. The approximation of the curve received in these experiments has shown that molecular structures comparable in mass with the protoviroid (a hypothetical primogenitor of the biosphere) and could have been synthesized as a result of the impact of a meteorite of a millimetre-size range. Observable characteristics of the synthesis processes suggest high catalytic activity of the plasma medium and high speed of plasma-chemical reactions, combined with ordering and assemblage processes. This suggests that the plasma torch with a huge local density of energy and matter may be the optimal medium for the synthesis of complex organic compounds needed for prebiotic evolution and the development of the primary form of living matter. A new view of the impact crater provides the most interesting and unexpected consequence of the concept proposed. When considering the problem, it became evident that at a prebiotic stage of evolution there should be an environment in which a photogenic creature could have survived. The crater of the meteoric impact, which is capable of producing ‘a primogenitor of the biosphere’ environment sated with organic matter, moderate temperature and water for considerable time and becoming ‘a life cradle’, appears to be such an environment. Having enormous energy, the meteorite impact is capable of injecting the newly created complicated organic compounds deep into the space body surfaces, including subsurface water reservoirs, such as Europe, Enchilada and Titan. In this case the meteorite impact has no natural alternative in the creation of initial conditions for the origin of extraterrestrial life. This possibility was confirmed by a laboratory impact model experiment, in which the plasma torch was created under the water surface. The concept proposed is based on physical processes occurring in nature and on experimental results of impact experiments and subsequent modelling of their analogues in laboratory conditions. Thus, the realizability and survivability of this concept should be taken as well grounded due to the simplicity and clarity of the physical processes.

Above detection limits - Prebiotic organics in comets and carbonaceous meteorites

NASA Astrophysics Data System (ADS)

Stern, J. C.; Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Martin, M. G.; Dworkin, J. P.

2009-12-01

The delivery of organic compounds such as amino acids and nucleobases by comets, asteroids, and their fragments may have contributed feedstock for prebiotic chemistry leading to the first self-replicating systems of the early Earth. In order to determine the isotopic composition, distribution, and abundance of prebiotic organic compounds in extraterrestrial samples we have recently optimized a highly sensitive liquid chromatography tandem quadupole mass spectrometer (LC-QqQ-MS) and a gas chromatography mass spectrometer coupled with an isotope ratio mass spectrometer (GC-MS/IRMS). This suite of instruments not only allows us to identify and quantify extremely trace amounts of organics of astrobiological interest, but also to confirm their extraterrestrial origins by stable isotopic measurements. The amino acid glycine was detected upon preliminary examinations of foils from NASA’s Stardust mission, which returned cometary material from comet 81P/Wild 2. To rule out the possibility of terrestrial contamination as the source of the glycine, the carbon isotopic ratio was measured. The δ13C value for glycine was determined to be +29 ± 6‰, well outside the terrestrial range for organic carbon of +6 ‰ to -40 ‰. The Stardust glycine δ13C value falls in the range previously reported for glycine (+22‰ to +41‰) in the carbonaceous meteorites Murchison and Orgueil. This represents the first detection of glycine or any other amino acid in a comet. Recent investigations of carbonaceous meteorite organic matter have revealed the presence of several nucleobases in the Murchison meteorite and several Antarctic CR meteorites never before analyzed for nucleobases using LC-QqQ-MS. This analytical tool is a sensitive and highly selective method for measuring the trace amounts of these organics in meteorites. In particular, the unusual Antarctic C2 meteorite, LON 94102, shows high abundances of guanine, hypoxanthine, and xanthine with concentrations ranging from 70 to 200 ppb. Nitrogen isotopic measurements will be made to determine the origin (extraterrestrial or terrestrial) of these compounds.

Micro-ion Traps for Detection of (Pre)-Biotic Organic Compounds on Comets

NASA Technical Reports Server (NTRS)

vanAmerom, Friso H. W.; Chaudhary, A.; Short, R. T.; Brinkerhoff, William; Glavin, Daniel; Mahaffy, Paul R.; Roman, Patrick A.

2013-01-01

Comets are currently believed to be a mixture of interstellar and nebular material. Many of the volatiles in comets are attributed to interstellar chemistry, because the same species of carbonaceous compounds are also observed in ices in interstellar molecular (ISM) clouds. Comets are thus likely to be a relatively pristine reservoir of primitive material and carbonaceous compounds in our solar system. They could be a major contributor to the delivery of prebiotic organic compounds, from which life emerged through impacts on early Earth. Mass spectrometers are very powerful tools to identify unknown chemicals, and much progress bas been made in miniaturizing mas spectrometers for space applications. Most miniatu rized mass spectrometers developed to date, however, are still relatively large, power hungry, complicated to assemble, and would have significant impact on space flight vehicle total payload and resource allocations.

Self-organization of the protocell was a forward process

NASA Technical Reports Server (NTRS)

Fox, S. W.; Matsuno, K.

1983-01-01

Yockey's (1981) interpretation of information theory relative to concepts of self-organization in the origin of life is criticized on the ground that it assumes that each amino acid residue type in a given sequence is an unaided information carrier throughout evolution. It is argued that more than one amino acid residue can act as a unit information carrier, and that this was the case in prebiotic protein evolution. Forward-extrapolation should be used to study prebiotic evolution, not backward-extrapolation. Transposing the near-random internal order of modern proteins to primitive proteins, as Yockey has done, is an unsupported assumption and disagrees with the results of experimental models of the primordial type. Studies indicate that early primary information carriers in evolution were mixtures of free alpha amino acids which necessarily had the capability of sequencing themselves.

Template-directed synthesis and selective adsorption of oligoadenylates in hydroxyapatite

NASA Technical Reports Server (NTRS)

Gibbs, D.; Lohrmann, R.; Orgel, L. E.

1980-01-01

Polyuridylic acid is adsorbed completely from aqueous solution by hydroxyapatite under conditions that permit template-directed synthesis of oligoadenylates in free solution. The yield of oligoadenylates is enhanced to almost the same extent by poly(U) in the presence or the absence of hydroxyapatite. Under very similar conditions small quantities of hydroxyapatite adsorb higher-molecular-weight oligoadenylates selectively from a mixture of oligomers. On the basis of these results a mechanism for prebiotic oligonucleotide formation is proposed in which selective adsorption on hydroxyapatite or some other immobilized anion-exchanging material plays a major role. Monomers are released from the surface for reactivation, while oligomers are retained in a protected environment by adsorption to the apatite surface.

Role of Phosphorus Minerals in the Origin of Life on Earth

NASA Astrophysics Data System (ADS)

Gull, M.; Pasek, M. A.

2013-12-01

In the origin of life, phosphorus (P) plays a vital role as it is a key biologic element (1). However, a big question still remains as to how P was incorporated into the first biomolecules as the availability of dissolved P in water is low. Orthophosphate minerals such as apatite, whitelockite and monetite are the major carriers of phosphate on Earth, but these are poorly soluble in water and are inert. The recent discovery of phosphite in Archean rocks (2) suggests that it is likely that some other source of P was present on the early Earth which could very well mix with Hadean Ocean to generate biomolecules. The meteoritic mineral schreibersite (SC thereafter) may have provided reduced P that would corrode into water and generate reactive inorganic P. In this study we present the significance of some important P minerals including apatite, whitelockite, monazite, struvite, monetite and meteoritic mineral SC (or its synthetic analogue Fe3P). Two major aspects of these P minerals were studied; first the release of P into water and second whether phosphorylation of organic compound (glycerol) could be carried out. It was seen all the phosphate minerals such as apatite, whitelockite, monazite and monetite when heated (65-75oC for 8-10 days) with an aqueous solution of 0.5 M glycerol gave no prominent phosphorylated products (P31NMR & mass spectrometry) and released very little amount of phosphate into water and remained inert. Struvite on heating with glycerol gave around 8-10 % of glycerol monophosphates along with phosphate release in the water. When SC (or Fe3P) was heated in an aqueous solution of glycerol it not only yielded 3-6 % glycerol monophosphates but also some glycerol-di-phosphate along with rich species of inorganic P compounds. SC from the meteorite Seymchan also demonstrated phosphorylation of glycerol. Since the prebiotic role of struvite mineral as a prebiotic P mineral is not clearly known (3), this suggests SC was a potential prebiotic P source (4). The beauty of these bio-geologic reactions is the one-pot synthesis of glycerol-1-phosphate, glycerol-2-phosphate along with glycerol-di-phosphate and many inorganic P species (orthophosphate, pyrophosphate, triphosphate, phosphite). This one-pot synthetic route could possibly be one of the most important steps in the emergence of life. The study focuses on the significance of meteoritic based origin of life and how meteorites would have played a significant role in the origin of biological phosphate esters/life on the early earth. Phosphorylation of organic compounds by meteoritic sources

Planetary Sources for Reducing Sulfur Compounds for Cyanosulfidic Origins of Life Chemistry

NASA Astrophysics Data System (ADS)

Ranjan, S.; Todd, Z. R.; Sutherland, J.; Sasselov, D. D.

2017-12-01

A key challenge in origin-of-life studies is understanding the chemistry that lead to the origin of the key biomolecules of life, such as the components of nucleic acids, sugars, lipids, and proteins. Prebiotic reaction networks based upon reductive homologation of nitriles (e.g., Patel et al. 2015), are building a tantalizing picture of sustained abiotic synthesis of activated ribonucleotides, amino acids and lipid precursors under environmental conditions thought to have been available on early Earth. Sulfidic anions in aqueous solution (e.g., HS-, HSO3-) under near-UV irradiation play important roles in these chemical pathways. However, the sources and availability of these anions on early Earth have not yet been quantitatively constrained. Here, we evaluate the potential for the atmosphere to serve as a source of sulfidic anions, via dissolution of volcanically-outgassed SO2 and H2S into water reservoirs. We combine photochemical modeling from the literature (Hu et al. 2013) with equilibrium chemistry calculations to place constraints on the partial pressures of SO2 and H2S required to reach the elevated concentrations of sulfidic anions (≥1 μM) thought to be necessary for prebiotic chemistry. We find that micromolar levels of SO2-derived anions (HSO3-, SO3(2-)) are possible through simple exposure of aqueous reservoirs like shallow lakes to the atmosphere, assuming total sulfur emission flux comparable to today. Millimolar levels of these compounds are available during the epochs of elevated volcanism, due to elevated sulfur emission flux. Radiative transfer modeling suggests the atmospheric sulfur will not block the near-UV radiation also required for the cyanosulfidic chemistry. However, H2S-derived anions (e.g., HS-) reach only sub-micromolar levels from atmospheric sources, meaning that prebiotic chemistry invoking such molecules must invoke specialized, local sources. Prebiotic chemistry invoking SO2-derived anions may be considered more robust than chemistry invoking H2S-derived anions. In general, epochs of moderately high volcanism may have been especially conducive to cyanosulfidic prebiotic chemistry.

Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment

PubMed Central

Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments. PMID:21422282

Primordial Synthesis of Amines and Amino Acids in a 1958 Miller H2S-Rich Spark Discharge Experiment

NASA Technical Reports Server (NTRS)

Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordia! environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

The origin and emergence of life under impact bombardment

PubMed Central

Cockell, Charles S

2006-01-01

Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's ‘warm little pond’. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology—generating large numbers of ‘experiments’ in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities. PMID:17008223

Trametes versicolor extract modifies human fecal microbiota composition in vitro.

PubMed

Yu, Zhuo-Teng; Liu, Bo; Mukherjee, Purna; Newburg, David S

2013-06-01

Trametes versicolor is a mushroom used as a traditional Chinese medicine (Yun-zhi) for a wide array of seemingly disparate conditions. We hypothesized that many of its multiple purported activities could be mediated through stimulation of beneficial mutualist components of the microbiota. Human fecal microbiota was cultured anaerobically to determine its ability to ferment a common extract of T. versicolor, designated polysaccharide peptide (PSP), and the ability of PSP to alter the composition of the microbial community. The presence of PSP and fructooligosaccharides (FOS, a common prebiotic) in the medium, but not cellulose, significantly increased levels of Bifidobacterium spp. PSP also elevated Lactobacillus spp., while reducing Clostridium spp., Staphylococcus spp. and Enterococcus spp. Levels of Streptococcus spp., Bacteroides spp. and Escherichia did not significantly change. Fermentation of PSP increased the concentration of organic acids (lactate and short-chain fatty acids), decreased the pH, and induced β-galactosidase and β-glucosidase activities. The genera of the human microbiota that are promoted by FOS and other prebiotics are also stimulated by the Trametes versicolor extract, PSP. Thus, Trametes versicolor, a common East Asian botanical, contains putative prebiotic agents that alter human gut microbiota and pH. This prebiotic-like activity may help explain some of the plethora of the health benefits attributed to this traditional Chinese medicine.

Meteors: A Delivery Mechanism of Organic Matter to The Early Earth

NASA Technical Reports Server (NTRS)

Jenniskens, Peter; Wilson, Mike A.; Packan, Dennis; Laux, Christophe O.; Krueger, Charles H.; Boyd, Iain, D.; Popova, Olga P.; Fonda, Mark; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

All potential exogenous pre-biotic matter arrived to Earth by ways of our atmosphere, where much material was ablated during a luminous phase called 1. meteors" in rarefied flows of high (up to 270) Mach number. The recent Leonid showers offered a first glimpse into the elusive physical conditions of the ablation process and atmospheric chemistry associated with high-speed meteors. Molecular emissions were detected that trace a meteor's brilliant light to a 4,300 K warm wake rather than to the meteor's head. A new theoretical approach using the direct simulation by Monte Carlo technique identified the source-region and demonstrated that the ablation process is critical in the heating of the meteor's wake. In the head of the meteor, organic carbon appears to survive flash heating and rapid cooling. The temperatures in the wake of the meteor are just right for dissociation of CO and the formation of more complex organic compounds. The resulting materials could account for the bulk of pre-biotic organic carbon on the early Earth at the time of the origin of life.

On the Maillard reaction of meteoritic amino acids

NASA Astrophysics Data System (ADS)

Kolb, Vera M.; Bajagic, Milica; Liesch, Patrick J.; Philip, Ajish; Cody, George D.

2006-08-01

We have performed the Maillard reaction of a series of meteoritic amino acids with sugar ribose under simulated prebiotic conditions, in the solid state at 65°C and at the room temperature. Many meteoritic amino acids are highly reactive with ribose, even at the room temperature. We have isolated high molecular weight products that are insoluble in water, and have studied their structure by the IR (infrared) and solid-state C-13 NMR (nuclear magnetic resonance) spectroscopic methods. The functional groups and their distribution were similar among these products, and were comparable to the previously isolated insoluble organic materials from the Maillard reaction of the common amino acids with ribose. In addition, there were some similarities with the insoluble organic material that is found on Murchison. Our results suggest that the Maillard products may contribute to the composition of the part of the insoluble organic material that is found on Murchison. We have also studied the reaction of sodium silicate solution with the Maillard mixtures, to elucidate the process by which the organic compounds are preserved under prebiotic conditions.

Sugars and Sugar Derivatives in Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

NASA Technical Reports Server (NTRS)

Nuevo, M.; Sandford, S. A.; Cooper, G.

2017-01-01

Carbonaceous chondrites contain a large variety of organic compounds of prebiotic interest, which include amino acids, amphiphiles, nucleobases, and sugar derivatives. The presence of these compounds strongly suggests that molecules essential to life can form abiotically under astrophysical conditions. Among the sugar derivatives reported in the Murchison and Murray meteorites, only one sugar (dihydroxyacetone) was found, together with a variety of sugar alcohols and sugar acids containing up to 6 carbon atoms, including sugar acid derivatives of the biological sugars ribose and glucose. On the other hand, laboratory studies on the formation of complex organic molecules from the ultraviolet (UV) irradiation of simulated astrophysical ice mixtures consisting of H2O, CO, CO2, CH3OH, CH4, NH3, etc., at low temperature have been routinely carried out in the past 15 years. These studies have shown that the organic residues recovered at room temperature contain amino acids, amphiphiles, nucleobases, as well as other complex organics, supporting a scenario in which molecules of prebiotic interest can form in extra-terrestrial environments.

Silica metal-oxide vesicles catalyze comprehensive prebiotic chemistry.

PubMed

Bizzarri, Bruno Mattia; Botta, Lorenzo; Pérez-Valverde, Maritza Iveth; Saladino, Raffaele; Di Mauro, Ernesto; Garcia Ruiz, Juan Manuel

2018-03-30

It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have synthesized self-assembled membranes by mixing microdrops of metal solutions with alkaline silicate solutions in the presence of formamide (NH2CHO), a single carbon molecule, at 80ºC. We found that these bilayer membranes, made of amorphous silica and metal oxide-hydroxide nanocrystals, catalyze the condensation of formamide, yielding the four nucleobases of RNA, three aminoacids and several carboxylic acids in a single pot experiment. Besides manganese, iron and magnesium, two abundant elements in the earliest Earth crust that are key in serpentinization reactions, are enough to produce all these biochemical compounds. These results suggest that the transition from inorganic geochemistry to prebiotic organic chemistry is common on a universal scale and, most probably, earlier than ever thought for our planet. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The adsorption of amino acids and cations onto goethite: a prebiotic chemistry experiment.

PubMed

Farias, Ana Paula S F; Carneiro, Cristine E A; de Batista Fonseca, Inês C; Zaia, Cássia T B V; Zaia, Dimas A M

2016-06-01

Few prebiotic chemistry experiments have assessed the adsorption of biomolecules by iron oxide-hydroxides. The present work investigated the effects of cations in artificial seawaters on the adsorption of Gly, α-Ala and β-Ala onto goethite, and vice versa. Goethite served to concentrate K and Mg cations from solution; these effects could have played important roles in peptide nucleoside formation. Goethite showed low adsorption of Gly and α-Ala. On the other hand, β-Ala (a non-protein amino acid) was highly adsorbed by goethite. Because Gly and α-Ala are the most common amino acids in living beings, and iron oxide-hydroxides are widespread on Earth, additional iron oxides should be studied. Increased ionic strength in artificial seawaters decreased the adsorption of amino acids by goethite. Because Na was highly abundant in the artificial seawater, it showed the highest effect on amino acid adsorption. β-Ala increased the adsorption of K and Ca by goethite, this effect could have been important for peptide synthesis.

Rotational and Infrared Spectroscopy of Ethanimine: A Route toward Its Astrophysical and Planetary Detection

NASA Astrophysics Data System (ADS)

Melli, Alessio; Melosso, Mattia; Tasinato, Nicola; Bosi, Giulio; Spada, Lorenzo; Bloino, Julien; Mendolicchio, Marco; Dore, Luca; Barone, Vincenzo; Puzzarini, Cristina

2018-03-01

Ethanimine, a possible precursor of amino acids, is considered an important prebiotic molecule and thus may play important roles in the formation of biological building blocks in the interstellar medium. In addition, its identification in Titan’s atmosphere would be important for understanding the abiotic synthesis of organic species. An accurate computational characterization of the molecular structure, energetics, and spectroscopic properties of the E and Z isomers of ethanimine, CH3CHNH, has been carried out by means of a composite scheme based on coupled-cluster techniques, which also account for extrapolation to the complete basis-set limit and core-valence correlation correction, combined with density functional theory for the treatment of vibrational anharmonic effects. By combining the computational results with new millimeter-wave measurements up to 300 GHz, the rotational spectrum of both isomers can be accurately predicted up to 500 GHz. Furthermore, our computations allowed us to revise the infrared spectrum of both E- and Z-CH3CHNH, thus predicting all fundamental bands with high accuracy.

Amino Acid Stability in the Early Oceans

NASA Technical Reports Server (NTRS)

Parker, E. T.; Brinton, K. L.; Burton, A. S.; Glavin, D. P.; Dworkin, J. P.; Bada, J. L.

2015-01-01

It is likely that a variety of amino acids existed in the early oceans of the Earth at the time of the origin and early evolution of life. "Primordial soup", hydrothermal vent, and meteorite based processes could have contributed to such an inventory. Several "protein" amino acids were likely present, however, based on prebiotic synthesis experiments and carbonaceous meteorite studies, non-protein amino acids, which are rare on Earth today, were likely the most abundant. An important uncertainty is the length of time these amino acids could have persisted before their destruction by abiotic and biotic processes. Prior to life, amino acid concentrations in the oceans were likely regulated by circulation through hydro-thermal vents. Today, the entire ocean circulates through vent systems every 10(exp 7) years. On the early Earth, this value was likely smaller due to higher heat flow and thus marine amino acid life-time would have been shorter. After life, amino acids in the oceans could have been assimilated by primitive organisms.

Ionizing radiation and life.

PubMed

Dartnell, Lewis R

2011-01-01

Ionizing radiation is a ubiquitous feature of the Cosmos, from exogenous cosmic rays (CR) to the intrinsic mineral radioactivity of a habitable world, and its influences on the emergence and persistence of life are wide-ranging and profound. Much attention has already been focused on the deleterious effects of ionizing radiation on organisms and the complex molecules of life, but ionizing radiation also performs many crucial functions in the generation of habitable planetary environments and the origins of life. This review surveys the role of CR and mineral radioactivity in star formation, generation of biogenic elements, and the synthesis of organic molecules and driving of prebiotic chemistry. Another major theme is the multiple layers of shielding of planetary surfaces from the flux of cosmic radiation and the various effects on a biosphere of violent but rare astrophysical events such as supernovae and gamma-ray bursts. The influences of CR can also be duplicitous, such as limiting the survival of surface life on Mars while potentially supporting a subsurface biosphere in the ocean of Europa. This review highlights the common thread that ionizing radiation forms between the disparate component disciplines of astrobiology. © Mary Ann Liebert, Inc.

A specific scenario for the origin of life and the genetic code based on peptide/oligonucleotide interdependence.

PubMed

Griffith, Robert W

2009-12-01

Among various scenarios that attempt to explain how life arose, the RNA world is currently the most widely accepted scientific hypothesis among biologists. However, the RNA world is logistically implausible and doesn't explain how translation arose and DNA became incorporated into living systems. Here I propose an alternative hypothesis for life's origin based on cooperation between simple nucleic acids, peptides and lipids. Organic matter that accumulated on the prebiotic Earth segregated into phases in the ocean based on density and solubility. Synthesis of complex organic monomers and polymerization reactions occurred within a surface hydrophilic layer and at its aqueous and atmospheric interfaces. Replication of nucleic acids and translation of peptides began at the emulsified interface between hydrophobic and aqueous layers. At the core of the protobiont was a family of short nucleic acids bearing arginine's codon and anticodon that added this amino acid to pre-formed peptides. In turn, the survival and replication of nucleic acid was aided by the peptides. The arginine-enriched peptides served to sequester and transfer phosphate bond energy and acted as cohesive agents, aggregating nucleic acids and keeping them at the interface.

Amino Acids in Asteroids and Comets: Implications for the Origin of Life on Earth and Possibly Elsewhere

NASA Technical Reports Server (NTRS)

Glavin, Daniel

2012-01-01

Meteorites provide a record of the chemical processes that occurred in the early solar system before life began on Earth. The delivery of organic matter by asteroids, comets, and their fragments to the Earth and other planetary bodies in our solar system could have been an important source of the prebiotic organic inventory needed for the emergence of life. Amino acids are essential components of proteins and enzymes in life on Earth and these prebiotic organic compounds have been detected in a wide variety of carbon-rich meteorites, the majority of which have been determined to be extraterrestrial in origin. In addition, many amino acids are structurally chiral (they possess handedness) and with a few very rare exceptions, only left handed (L) amino acids are found in biology, while all known abiotic syntheses of amino acids result in equal mixtures of left and right handed (LD) amino acids. The discovery of a significant left handed amino acid imbalance of up to 20% in several different carbonaceous meteorites, could point toward a possible prebiotic contribution to the origin of biological homochirality by the exogenous delivery of extraterrestrial organic material to the early Earth. In this talk, I will focus on recent state-of-the-art measurements of the distribution, chirality, and isotopic composition of amino acids in meteorites and cometary samples carried out at the Goddard Astrobiology Analytical Laboratory. Results from the analyses of a variety of Antarctic meteorites, samples from comet Wild 2 returned by the STARDUST mission, and meteorite fragments of asteroid 2008 TC3 called Almahata Sitta recovered from northern Sudan will be discussed

Acetylene-based pathways for prebiotic evolution on Titan

NASA Astrophysics Data System (ADS)

Abbas, O.; Schulze-Makuch, D.

2002-11-01

Due to Titan's reducing atmosphere and lack of an ozone shield, ionizing radiation penetrates the atmosphere creating ions, radicals and electrons that are highly reactive producing versatile chemical species on Titan's surface. We propose that the catalytic hydrogenation of photochemically produced acetylene may be used as simple metabolic pathway by organisms at or near Titan's surface. While the acetylene may undergo this reaction, it can also undertake several other multi-step synthetic schemes that eventually lead to the production of amino acids or other biologically important molecules. Four model synthetic schemes will be described, and their relevance in relation to prebiotic evolution on Earth is discussed.

Prebiotic chemistry and nucleic acid replication

NASA Technical Reports Server (NTRS)

Orgel, L. E.; Lohrmann, R.

1974-01-01

Recent work is reviewed on some reactions that could have occurred on the primitive earth and that could have played a part in the evolution of a self-replicating system. The transition from the primitive atmosphere to the simplest replicating molecules is considered in four stages: (1) the formation of a 'prebiotic soup' of organic precursors, including the purine and pyrimidine bases and the pentose sugars; (2) the condensation of these precursors and inorganic phosphate to form monomeric nucleotides and activated nucleotide derivatives; (3) the polymerization of nucleotide derivatives to oligonucleotides; and (4) the complementary replication of oligonucleotides in a template-directed process that depends on Watson-Crick base pairing.

Organic chemistry in a CO2 rich early Earth atmosphere

NASA Astrophysics Data System (ADS)

Fleury, Benjamin; Carrasco, Nathalie; Millan, Maëva; Vettier, Ludovic; Szopa, Cyril

2017-12-01

The emergence of life on the Earth has required a prior organic chemistry leading to the formation of prebiotic molecules. The origin and the evolution of the organic matter on the early Earth is not yet firmly understood. Several hypothesis, possibly complementary, are considered. They can be divided in two categories: endogenous and exogenous sources. In this work we investigate the contribution of a specific endogenous source: the organic chemistry occurring in the ionosphere of the early Earth where the significant VUV contribution of the young Sun involved an efficient formation of reactive species. We address the issue whether this chemistry can lead to the formation of complex organic compounds with CO2 as only source of carbon in an early atmosphere made of N2, CO2 and H2, by mimicking experimentally this type of chemistry using a low pressure plasma reactor. By analyzing the gaseous phase composition, we strictly identified the formation of H2O, NH3, N2O and C2N2. The formation of a solid organic phase is also observed, confirming the possibility to trigger organic chemistry in the upper atmosphere of the early Earth. The identification of Nitrogen-bearing chemical functions in the solid highlights the possibility for an efficient ionospheric chemistry to provide prebiotic material on the early Earth.

Complex organic molecules toward low-mass and high-mass star forming regions

NASA Astrophysics Data System (ADS)

Favre, C.; Ceccarelli, C.; Lefloch, B.; Bergin, E.; Carvajal, M.; Brouillet, N.; Despois, D.; Jørgensen, J.; Kleiner, I.

2016-12-01

One of the most important questions in molecular astrophysics is how, when, and where complex organic molecules, COMs (≥ 6 atoms) are formed. In the Interstellar-Earth connection context, could this have a bearing on the origin of life on Earth? Formation mechanisms of COMs, which include potentially prebiotic molecules, are still debated and may include grain-mantle and/or gas-phase chemistry. Understanding the mechanisms that lead to the interstellar molecular complexification, along with the involved physicochemical processes, is mandatory to answer the above questions. In that context, active researches are ongoing in theory, laboratory experiment, chemical modeling and observations. Thanks to recent progress in radioastronomy instrumentation for both single-dish and millimeter array (e.g. Herschel, NOEMA, ALMA), new results have been obtained. I will review some notable results on the detection of COMs, including prebiotic molecules, towards star forming regions.

On the possibility of life on early Mars

NASA Technical Reports Server (NTRS)

Oberbeck, V. R.; Fogleman, G.

1990-01-01

Prebiotic reactants, liquid water, and temperatures low enough for organic compounds to be stable are requirements for the origination of life as we know it. Prebiotic reactants and sufficiently low temperatures were present on Mars before liquid water vanished. Early in this time period, however, large planetesimal impacts may have periodically sterilized Mars, pyrolyzed organic compounds, and interrupted chemical origination of life. However, the calculated time interval between such impacts on Mars was larger just before liquid water vanished 3.8 Gyr (billion years) ago than it was on earth just before life originated. Therefore, there should have been sufficient time for life to originate on Mars. Ideal sites to search for microfossils are in the heavily cratered terrain of Upper Noachian age. Craters and channels in this terrain may have been the sites of ancient lakes and streams that could have provided habitats for the first microorganisms.

The origin and early evolution of life on earth

NASA Technical Reports Server (NTRS)

Oro, J.; Miller, Stanley L.; Lazcano, Antonio

1990-01-01

Results of the studies that have provided insights into the cosmic and primitive earth environments are reviewed with emphasis on those environments in which life is thought to have originated. The evidence bearing on the antiquity of life on the earth and the prebiotic significance of organic compounds found in interstellar clouds and in primitive solar-system bodies such as comets, dark asteroids, and carbonaceous chondrites are assessed. The environmental models of the Hadean and early Archean earth are discussed, as well as the prebiotic formation of organic monomers and polymers essential to life. The processes that may have led to the appearance in the Archean of the first cells are considered, and possible effects of these processes on the early steps of biological evolution are analyzed. The significance of these results to the study of the distribution of life in the universe is evaluated.

Chiral encoding may provide a simple solution to the origin of life

NASA Astrophysics Data System (ADS)

Brewer, Ashley; Davis, Anthony P.

2014-07-01

The route by which the complex and specific molecules of life arose from the 'prebiotic soup' remains an unsolved problem. Evolution provides a large part of the answer, but this requires molecules that can carry information (that is, exist in many variants) and can replicate themselves. The process is commonplace in living organisms, but not so easy to achieve with simple chemical systems. It is especially difficult to contemplate in the chemical chaos of the prebiotic world. Although popular in many quarters, the notion that RNA was the first self-replicator carries many difficulties. Here, we present an alternative view, suggesting that there may be undiscovered self-replication mechanisms possible in much simpler systems. In particular, we highlight the possibility of information coding through stereochemical configurations of substituents in organic polymers. We also show that this coding system leads naturally to enantiopurity, solving the apparent problem of biological homochirality.

Organics on Titan : Carbon Rings and Carbon Cycles (Invited)

NASA Astrophysics Data System (ADS)

Lorenz, R. D.

2010-12-01

The photochemical conversion of methane into heavier organics which would cover Titan’s surface has been a principal motif of Titan science for the last 4 decades. Broadly, this picture has held up against Cassini observations, but organics on Titan turn out to have some surprising characteristics. First, the surface deposits of organics are segregated into at least two distinct major reservoirs - equatorial dune sands and polar seas. Second, the rich array of compounds detected as ions and molecules even 1000km above Titan’s surface has proven much more complex than expected, including two-ring anthracene and compounds with m/z>1000. Radar and near-IR mapping shows that Titan’s vast dunefields, covering >10% of Titan’s surface, contain ~0.3 million km^3 of material. This material is optically dark and has a low dielectric constant, consistent with organic particulates. Furthermore, the dunes are associated with a near-IR spectral signature attributed to aromatic compounds such as benzene, which has been sampled in surprising abundance in Titan’s upper atmosphere. The polar seas and lakes of ethane (and presumably at least some methane) may have a rather lower total volume than the dune sands, and indeed may contain little more, if any, methane than the atmosphere itself. The striking preponderance of liquid deposits in the north, notably the 500- and 1000-km Ligeia and Kraken, contrasts with the apparently shallow and shrinking Ontario Lacus in the south, and perhaps attests to volatile migration on astronomical (Croll-Milankovich) timescales as well as seasonal methane transport. Against this appealing picture, many questions remain. What is the detailed composition of the seas, and can chemistry in a nonpolar solvent yield compounds of astrobiological interest ? Are there ‘groundwater’ reservoirs of methane seething beneath the surface, perhaps venting to form otherwise improbable equatorial clouds? And what role, if any, do clathrates play today? What are the inscrutably amorphous midlatitude terrains made of ? Is Titan’s bulk crust made of water ice? Only a few places show evidence of water ice bedrock (notably fluvial debris, and the fresh-looking Sinlap ejecta blanket). This may relate to another puzzle - the apparently karstic depressions, many of which are filled with hydrocarbon lakes, found in the polar regions. Low solubility makes etching of hundred-meter deep depressions in ice rather improbable. Perhaps the crust comprises shock-processed organic material from early in Titan’s history, as well as photolysis/radiolysis products forming today. Are the flow-like features detected in a number of places such as Hotei, ‘classical’ ammonia-water cryolavas as claimed, merely geomorphological delusions, or are they some reprocessed organic material heated or squeezed in the interior ? A terrestrial analog might be the salt glaciers of Iran, or in sci-fi the ‘waxworms’ of Titan in Arthur C. Clarke’s ‘Imperial Earth’. Classic cryovolcanism (and impact melt) is of course of interest for the known prebiotic synthesis pathways via hydrolysis of tholins, but some recent work suggests that at least trace prebiotic synthesis may occur in the gas phase via oxygen-bearing molecules sprinkled into the upper atmosphere by ablation of icy meteoroids and O+ ions from Enceladus. In any case, Titan presents us with an abundant and rich inventory of organics.

Formation of nucleoside 5'-polyphosphates under potentially prebiological conditions

NASA Technical Reports Server (NTRS)

Lohrmann, R.

1976-01-01

The characteristics and efficiencies of biochemical reactions involving nucleoside 5'-diphosphates and -triphosphates (important substrates of RNA and DNA synthesis) under conditions corresponding to the primitive prebiotic earth are investigated. Urea catalysis of the formation of linear inorganic polyphosphates and metal ions promoting the reactions are discussed. Linear polyphosphate was incubated with Mg(++) in the presence of a nucleoside 5'-phosphate, to yield nucleoside 5'-polyphosphates when products are dried, while Mg(++) prompts depolymerization to trimetaphosphate in aqueous solutions. Plausible biogenetic pathways are examined.

Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics.

PubMed

Gibson, Glenn R; Hutkins, Robert; Sanders, Mary Ellen; Prescott, Susan L; Reimer, Raylene A; Salminen, Seppo J; Scott, Karen; Stanton, Catherine; Swanson, Kelly S; Cani, Patrice D; Verbeke, Kristin; Reid, Gregor

2017-08-01

In December 2016, a panel of experts in microbiology, nutrition and clinical research was convened by the International Scientific Association for Probiotics and Prebiotics to review the definition and scope of prebiotics. Consistent with the original embodiment of prebiotics, but aware of the latest scientific and clinical developments, the panel updated the definition of a prebiotic: a substrate that is selectively utilized by host microorganisms conferring a health benefit. This definition expands the concept of prebiotics to possibly include non-carbohydrate substances, applications to body sites other than the gastrointestinal tract, and diverse categories other than food. The requirement for selective microbiota-mediated mechanisms was retained. Beneficial health effects must be documented for a substance to be considered a prebiotic. The consensus definition applies also to prebiotics for use by animals, in which microbiota-focused strategies to maintain health and prevent disease is as relevant as for humans. Ultimately, the goal of this Consensus Statement is to engender appropriate use of the term 'prebiotic' by relevant stakeholders so that consistency and clarity can be achieved in research reports, product marketing and regulatory oversight of the category. To this end, we have reviewed several aspects of prebiotic science including its development, health benefits and legislation.

Transgalactosylation and hydrolytic activities of commercial preparations of β-galactosidase for the synthesis of prebiotic carbohydrates.

PubMed

Guerrero, Cecilia; Vera, Carlos; Conejeros, Raúl; Illanes, Andrés

2015-03-01

β-Galactosidases exhibit both hydrolytic and transgalactosylation activities; the former has been used traditionally for the production of delactosed milk and dairies, while the latter is being increasingly used for the synthesis of lactose-derived oligosaccharides: balance between both activities was highly dependent on the enzyme origin: β-galactosidases from Aspegillus oryzae and Bacillus circulans exhibited high transgalactosylation activity, while those from one from Kluyveromyces exhibited high hydrolytic activity but quite low transgalactosylation activity. Also the affinity for the donors (lactose or lactulose) and the acceptors (lactose, lactulose or fructose) of transgalactosylated galactose was dependent on the enzyme origin, as reflected by the Michaelis constants obtained in the synthesis of galacto-oligosaccharides, fructosyl-galacto-oligosaccharides and lactulose. Finally, the balance between transgalactosylation and hydrolytic activities of β-galactosidases could be tuned by changing the concentration of galactose donor. Copyright © 2014 Elsevier Inc. All rights reserved.

Stability of prebiotic, laminaran oligosaccharide under food processing conditions

NASA Astrophysics Data System (ADS)

Chamidah, A.

2018-04-01

Prebiotic stability tests on laminaran oligosaccharide under food processing conditions were urgently performed to determine the ability of prebiotics deal with processing. Laminaran, oligosaccharide is produced from enzymatic hydrolysis. To further apply this prebiotic, it is necessary to test its performance on food processing. Single prebiotic or in combination with probiotic can improve human digestive health. The effectiveness evaluation of prebiotic should be taken into account in regards its chemical and functional stabilities. This study aims to investigate the stability of laminaran, oligosaccharide under food processing condition.

Prebiotics: application in bakery and pasta products.

PubMed

Padma Ishwarya, S; Prabhasankar, P

2014-01-01

The concept of functional foods has markedly moved toward gastrointestinal health. The prebiotic approach aims at achieving favorable milieu in the human gut by stimulating beneficial bacteria. Several food products act as substrates for the application of prebiotic substances and bakery products are one such category. The trend of increasing consumption of bakery products justifies the choice of using them as vehicles for delivering the prebiotic compounds. Apart from the health benefits, the prebiotic compounds also have nutritional and technological effects in the food matrix. In addition to increasing the fiber content, the candidate prebiotics also affect the rheology and final quality of bakery products. The prebiotic compounds are selected accordingly to confer desirable properties in the final product. The health advantages of prebiotics being well established, the technological advantages in bakery products such as bread and biscuits and extruded product such as pasta are discussed elaborately.

Bioastrophysical aspects of low energy ion irradiation of frozen anthracene containing water.

PubMed

Tuleta, M; Gabła, L; Madej, J

2001-08-13

The origin of life on Earth remains a fascinating mystery in spite of many theories existing on this subject. However, it seems that simple prebiotic molecules could play an essential role in the formation of more complex organisms. In our experiment, we synthesized a class of these molecules (quinones) bombarding frozen anthracene containing water with low energy hydrogen ions. This experiment roughly simulated the astrophysical conditions which one can find in the solar system. Thus, we can hypothesize that prebiotic molecules could be created by interaction of the solar wind with interplanetary dust grains. The delivery of these molecules to early Earth may have contributed to the generation of life on our planet.

Prebiotics in Companion and Livestock Animal Nutrition

NASA Astrophysics Data System (ADS)

Barry, Kathleen A.; Vester, Brittany M.; Fahey, George C.

Prebiotic supplementation of animal diets began in an attempt to increase concentrations of beneficial intestinal microbiota. It was understood that prebiotics inhibited growth of intestinal pathogens and decreased concentrations of stool odor-causing metabolites. Since the use of prebiotics began, several countries have banned the use of antimicrobials in livestock animal feeds, and several more have placed restrictions on the quantity of antimicrobials that can be used. Prebiotic supplementation has become increasingly popular as the body of evidence supporting its use continues to grow. As this literature expands, the number of potential prebiotic substances has grown beyond those that are naturally occurring, such as those found in chicory and yeast products, to include a large number of synthetic or chemically/enzymatically manufactured prebiotics.

227 Views of RNA: Is RNA Unique in Its Chemical Isomer Space?

PubMed Central

Meringer, Markus; Goodwin, Jay

2015-01-01

Abstract Ribonucleic acid (RNA) is one of the two nucleic acids used by extant biochemistry and plays a central role as the intermediary carrier of genetic information in transcription and translation. If RNA was involved in the origin of life, it should have a facile prebiotic synthesis. A wide variety of such syntheses have been explored. However, to date no one-pot reaction has been shown capable of yielding RNA monomers from likely prebiotically abundant starting materials, though this does not rule out the possibility that simpler, more easily prebiotically accessible nucleic acids may have preceded RNA. Given structural constraints, such as the ability to form complementary base pairs and a linear covalent polymer, a variety of structural isomers of RNA could potentially function as genetic platforms. By using structure-generation software, all the potential structural isomers of the ribosides (BC5H9O4, where B is nucleobase), as well as a set of simpler minimal analogues derived from them, that can potentially serve as monomeric building blocks of nucleic acid–like molecules are enumerated. Molecules are selected based on their likely stability under biochemically relevant conditions (e.g., moderate pH and temperature) and the presence of at least two functional groups allowing the monomers to be incorporated into linear polymers. The resulting structures are then evaluated by using molecular descriptors typically applied in quantitative structure–property relationship (QSPR) studies and predicted physicochemical properties. Several databases have been queried to determine whether any of the computed isomers had been synthesized previously. Very few of the molecules that emerge from this structure set have been previously described. We conclude that ribonucleosides may have competed with a multitude of alternative structures whose potential proto-biochemical roles and abiotic syntheses remain to be explored. Key Words: Evolution—Chemical evolution—Exobiology—Prebiotic chemistry—RNA world. Astrobiology 15, 538–558. PMID:26200431

Effects of prebiotics on immune system and cytokine expression.

PubMed

Shokryazdan, Parisa; Faseleh Jahromi, Mohammad; Navidshad, Bahman; Liang, Juan Boo

2017-02-01

Nowadays, use of prebiotics as feed and food additives has received increasing interest because of the beneficial effects of prebiotics on the health of animals and humans. One of the beneficial effects of prebiotics is stimulation of immune system, which can be direct or indirect through increasing population of beneficial microbes or probiotics, especially lactic acid bacteria and bifidobacteria, in the gut. An important mechanism of action of probiotics and prebiotics, by which they can affect the immune system, is changing the expression of cytokines. The present review tried to summarize the findings of studies that investigated the effects of prebiotics on immune system with focusing on their effects on cytokine expression. Generally, most of reviewed studies indicated beneficial effects for prebiotics in terms of improving immune system, by increasing the expression of anti-inflammatory cytokines, while reducing the expressions of proinflammatory cytokines. However, most of studies mainly considered the indirect effects of prebiotics on the immune system (through changing the composition and population of gut microbiota), and their direct effects still need to be further studied using prebiotics with different degree of polymerization in different hosts.

The delivery of organic matter from asteroids and comets to the early surface of Mars

NASA Technical Reports Server (NTRS)

Flynn, G. J.

1996-01-01

Carbon delivered to the Earth by interplanetary dust particles may have been an important source of pre-biotic organic matter (Anders, 1989). Interplanetary dust is shown to deliver an order-of-magnitude higher surface concentration of carbon onto Mars than onto Earth, suggesting interplanetary dust may be an important source of carbon on Mars as well.

The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins.

PubMed

Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

2016-03-24

It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks ("seeds") for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn's largest moon, Titan.

The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins

PubMed Central

Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

2016-01-01

It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks (“seeds”) for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn’s largest moon, Titan. PMID:27023520

Sugar and Sugar Derivatives in Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

NASA Technical Reports Server (NTRS)

Nuevo, M.; Sandford, S. A.; Cooper, G.

2016-01-01

A large variety and number of organic compounds of prebiotic interest are known to be present in carbonaceous chondrites. Among them, one sugar (dihydroxyacetone) as well as several sugar acids, sugar alcohols, and other sugar derivatives have been reported in the Murchison and Murray meteorites. Their presence, along with amino acids, amphiphiles, and nucleobases strongly suggests that molecules essential to life can form abiotically under astrophysical conditions. This hypothesis is supported by laboratory studies on the formation of complex organic molecules from the ultraviolet (UV) irradiation of simulated astrophysical ice mixtures consisting of H2O, CO, CO2, CH3OH, CH4, NH3, etc., at low temperature. In the past 15 years, these studies have shown that the organic residues recovered at room temperature contain amino acids, amphiphiles, nucleobases, as well as other complex organics. However, no systematic search for the presence of sugars and sugar derivatives in laboratory residues have been reported to date, despite the fact that those compounds are of primary prebiotic significance. Indeed, only small (up to 3 carbon atoms) sugar derivatives including glycerol and glyceric acid have been detected in residues so far.

Prebiotic mechanisms, functions and application

USDA-ARS?s Scientific Manuscript database

In October 2012, a group of scientists met at the 10th Meeting of the International Scientific Association of Probiotics and Prebiotics (ISAPP) in Cork, Ireland to discuss issues surrounding prebiotics and their development. This article summarises outputs from the meeting. Various prebiotic defin...

Prebiotics: why definitions matter

PubMed Central

Hutkins, Robert W; Krumbeck, Janina A; Bindels, Laure B; Cani, Patrice D; Fahey, George; Goh, Yong Jun; Hamaker, Bruce; Martens, Eric C; Mills, David A; Rastal, Robert A; Vaughan, Elaine; Sanders, Mary Ellen

2015-01-01

The prebiotic concept was introduced twenty years ago, and despite several revisions to the original definition, the scientific community has continued to debate what it means to be a prebiotic. How prebiotics are defined is important not only for the scientific community, but also for regulatory agencies, the food industry, consumers and healthcare professionals. Recent developments in community-wide sequencing and glycomics have revealed that more complex interactions occur between putative prebiotic substrates and the gut microbiota than previously considered. A consensus among scientists on the most appropriate definition of a prebiotic is necessary to enable continued use of the term. PMID:26431716

Dimerization in Highly Concentrated Solutions of Phosphoimidazolide Activated Mononucleotides

NASA Technical Reports Server (NTRS)

Kanavarioti, Anastassia

1997-01-01

Phosphoimidazolide activated ribomononucleotides (*pN) are useful substrates for the non-enzymatic synthesis of polynucleotides. However, dilute neutral aqueous solutions of *pN typically yield small amounts of dimers and traces of polymers; most of *pN hydrolyzes to yield nucleoside 5'-monophosphate. Here we report the self-condensation of nucleoside 5'-phosphate 2- methylimidazolide (2-MeImpN with N = cytidine, uridine or guanosine) in the presence of Mg2(+) in concentrated solutions, such as might have been found in an evaporating lagoon on prebiotic Earth. The product distribution indicates that oligomerization is favored at the expense of hydrolysis. At 1.0 M, 2-MelmpU and 2-MelmpC produce about 65% of oligomers including 4% of the 3',5'-Iinked dimer. Examination of the product distribution of the three isomeric dimers in a self-condensation allows identification of reaction pathways that lead to dimer formation. Condensations in a concentrated mixture of all three nucleotides (U,C,G mixtures) is made possible by the enhanced solubility of 2-MeImpG in such mixtures. Although percent yield of intemucleotide linked dimers is enhanced as a function of initial monomer concentration, pyrophosphate dimer yields remain practically unchanged at about 20% for 2-MelmpU, 16% for 2-MeImpC and 25% of the total pyrophosphate in the U,C,G mixtures. The efficiency by which oligomers are produced in these concentrated solutions makes the evaporating lagoon scenario a potentially interesting medium for the prebiotic synthesis of dimers and short RNAs.

Prebiotic stereoselective synthesis of purine and noncanonical pyrimidine nucleotide from nucleobases and phosphorylated carbohydrates.

PubMed

Kim, Hyo-Joong; Benner, Steven A

2017-10-24

According to a current "RNA first" model for the origin of life, RNA emerged in some form on early Earth to become the first biopolymer to support Darwinism here. Threose nucleic acid (TNA) and other polyelectrolytes are also considered as the possible first Darwinian biopolymer(s). This model is being developed by research pursuing a "Discontinuous Synthesis Model" (DSM) for the formation of RNA and/or TNA from precursor molecules that might have been available on early Earth from prebiotic reactions, with the goal of making the model less discontinuous. In general, this is done by examining the reactivity of isolated products from proposed steps that generate those products, with increasing complexity of the reaction mixtures in the proposed mineralogical environments. Here, we report that adenine, diaminopurine, and hypoxanthine nucleoside phosphates and a noncanonical pyrimidine nucleoside (zebularine) phosphate can be formed from the direct coupling reaction of cyclic carbohydrate phosphates with the free nucleobases. The reaction is stereoselective, giving only the β-anomer of the nucleotides within detectable limits. For purines, the coupling is also regioselective, giving the N -9 nucleotide for adenine as a major product. In the DSM, phosphorylated carbohydrates are presumed to have been available via reactions explored previously [Krishnamurthy R, Guntha S, Eschenmoser A (2000) Angew Chem Int Ed 39:2281-2285], while nucleobases are presumed to have been available from hydrogen cyanide and other nitrogenous species formed in Earth's primitive atmosphere. Published under the PNAS license.

Titan's organic chemistry: Results of simulation experiments

NASA Technical Reports Server (NTRS)

Sagan, Carl; Thompson, W. Reid; Khare, Bishun N.

1992-01-01

Recent low pressure continuous low plasma discharge simulations of the auroral electron driven organic chemistry in Titan's mesosphere are reviewed. These simulations yielded results in good accord with Voyager observations of gas phase organic species. Optical constants of the brownish solid tholins produced in similar experiments are in good accord with Voyager observations of the Titan haze. Titan tholins are rich in prebiotic organic constituents; the Huygens entry probe may shed light on some of the processes that led to the origin of life on Earth.

Recent Development of Prebiotic Research—Statement from an Expert Workshop

PubMed Central

La Fata, Giorgio; Rastall, Robert A.; Lacroix, Christophe; Harmsen, Hermie J. M.; Mohajeri, M. Hasan; Weber, Peter

2017-01-01

A dietary prebiotic is defined as ‘a substrate that is selectively utilized by host microorganisms conferring a health benefit’. Although this definition evolved concomitantly with the knowledge and technological developments that accrued in the last twenty years, what qualifies as prebiotic continues to be a matter of debate. In this statement, we report the outcome of a workshop where academic experts working in the field of prebiotic research met with scientists from industry. The workshop covered three main topics: (i) evolution of the prebiotic concept/definition; (ii) the gut modeling in vitro technology PolyFermS to study prebiotic effects; and (iii) the potential novel microbiome-modulating effects associated with vitamins. The future of prebiotic research is very promising. Indeed, the technological developments observed in recent years provide scientists with powerful tools to investigate the complex ecosystem of gut microbiota. Combining multiple in vitro approaches with in vivo studies is key to understanding the mechanisms of action of prebiotics consumption and their potential beneficial effects on the host. PMID:29261110

Organic Selenium, Probiotics, and Prebiotics Effects on Growth, Blood Biochemistry, and Carcass Traits of Growing Rabbits During Summer and Winter Seasons.

PubMed

Ayyat, Mohamed S; Al-Sagheer, Adham A; Abd El-Latif, Khaled M; Khalil, Bakry A

2018-03-07

The effect of organic selenium, prebiotics, or probiotics on productive performances, blood biochemistry, and carcass characteristics of growing rabbits was studied throughout summer and winter seasons. In an 8-week feeding trial, a total of 100 New Zealand White rabbits were randomly distributed to 10 groups. Two seasons (winter and summer) and five diets fortified with 0 (control), 0.03 mg selenium, 3 g Bio-Mos®, 1 g Bactocell® (1 × 10 10  CFU) or 3 g yeast/kg diet were used in 2 × 5 factorial design. Results indicated that growth performance, feed intake (FI), and blood components (red blood cells [RBCs], serum total protein [TP], globulin [GLOB], albumin [ALB]) decreased significantly in rabbits reared during summer than in those during winter. In contrast, white blood cells, urea-N, creatinine, alanine transaminase [ALT], and aspartate transaminase [AST] increased significantly in summer. However, growth performance indices, FI, blood hemoglobin, RBCs, TP, ALB, and GLOB increased significantly in rabbits when fed the tested feed additives. The respiration rate, rectal temperature, and heart rate of the animals were significantly decreased with all feed additives. Adjusted weight of carcass, liver, kidney fat, and carcass cuts were not affected by feed additives. Final margin and margin efficiency increased in rabbit fed diets supplemented with feed additives than those fed the basal diet without any supplementation. Results of the current study concluded that a supplementation of rabbit diets with organic selenium, probiotics, and prebiotics can promote rabbit performance during mild weather and also alleviate the adverse impact of heat stress during summer season.

Prebiotics and probiotics: the prevention and reduction in severity of atopic dermatitis in children.

PubMed

Foolad, N; Armstrong, A W

2014-06-01

The purpose of this review was to identify whether supplementation with prebiotics and/or probiotics help prevent the development or reduce the severity of atopic dermatitis in children less than three years of age. Since 1997, immunostimulatory supplements, such as prebiotics and probiotics, have been investigated. Various supplementations include probiotics (single strain or mix), probiotics with formula, probiotics mix with prebiotics, and prebiotics. In this narrative review, we examined 13 key articles on prebiotics and/or probiotics, and their effects on infant atopic dermatitis. Among the selected studies, a total of 3,023 participants received supplements or placebo. Eight out of the 13 (61.5%) studies reported a significant effect on the prevention of atopic dermatitis after supplementation with probiotics and/or prebiotics. Five out of the 13 (38.5%) studies indicated significant reduction in the severity of atopic dermatitis after supplementation. Based on the available studies, supplementation with certain probiotics (Lactobacillus rhamnosus GG) appears to be an effective approach for the prevention and reduction in severity of atopic dermatitis. A mix of specific probiotic strains prevented atopic dermatitis among infants. Based on studies with prebiotics, there was a long-term reduction in the incidence of atopic dermatitis. Supplementation with prebiotics and probiotics appears useful for the reduction in the severity of atopic dermatitis. Additional interventional studies exploring prebiotics and probiotics are imperative before recommendations can be made.

Synthesis of Stachyobifiose Using Bifidobacterial α-Galactosidase Purified from Recombinant Escherichia coli.

PubMed

Oh, So Young; Youn, So Youn; Park, Myeong Soo; Baek, Nam In; Ji, Geun Eog

2018-02-07

The prebiotic effects of GOS (galactooligosaccharides) are known to depend on the glycosidic linkages, degree of polymerization (DP), and the monosaccharide composition. In this study, a novel form of α-GOS with a potentially improved prebiotic effect was synthesized using bifidobacterial α-galactosidase (α-Gal) purified from recombinant Escherichia coli. The carbohydrate produced was identified as α-d-galactopyranosyl-(1→6)-O-α-d-glucopyranosyl-(1→2)-[α-d-galactopyranosyl-(1→6)-O-β-d-fructofuranoside] and was termed stachyobifiose. Among 17 nonprobiotics, 16 nonprobiotics showed lower growth on stachyobifiose than β-GOS. In contrast, among the 16 probiotics, 6 probiotics showed higher growth on stachyobifiose than β-GOS. When compared with raffinose, stachyobifiose was used less by nonprobiotics than raffinose. Moreover, compared with stachyose, stachyobifiose was used less by Escherichia coli, Enterobacter cloacae, and Clostridium butyricum. The average amounts of total short-chain fatty acids (SCFA) produced were in the order of stachyobifiose > stachyose > raffinose > β-GOS. Taken together, stachyobifiose is expected to contribute to beneficial changes of gut microbiota.

Dietary prebiotics: Current status and new definition

USDA-ARS?s Scientific Manuscript database

In November 2008, a group of scientists met at the 6th Meeting of the International Scientific Association of Probiotics and Prebiotics (ISAPP) in London, Ontario. The aim was to discuss the functionality of prebiotics. As a result of this, it was decided that the prebiotic field as it stands is dom...

Organic matter in carbonaceous meteorites: past, present and future research.

PubMed

Sephton, Mark A

2005-12-15

Carbonaceous meteorites are fragments of ancient asteroids that have remained relatively unprocessed since the formation of the Solar System. These carbon-rich objects provide a record of prebiotic chemical evolution and a window on the early Solar System. Many compound classes are present reflecting a rich organic chemical environment during the formation of the planets. Recent theories suggest that similar extraterrestrial organic mixtures may have acted as the starting materials for life on Earth.

Urea, Glycolic Acid, and Glycerol in an Organic Residue Produced by Ultraviolet Irradiation of Interstellar/Pre-Cometary Ice Analogs

NASA Astrophysics Data System (ADS)

Nuevo, Michel; Bredehöft, Jan Hendrik; Meierhenrich, Uwe J.; d'Hendecourt, Louis; Thiemann, Wolfram H.-P.

2010-03-01

More than 50 stable organic molecules have been detected in the interstellar medium (ISM), from ground-based and onboard-satellite astronomical observations, in the gas and solid phases. Some of these organics may be prebiotic compounds that were delivered to early Earth by comets and meteorites and may have triggered the first chemical reactions involved in the origin of life. Ultraviolet irradiation of ices simulating photoprocesses of cold solid matter in astrophysical environments have shown that photochemistry can lead to the formation of amino acids and related compounds. In this work, we experimentally searched for other organic molecules of prebiotic interest, namely, oxidized acid labile compounds. In a setup that simulates conditions relevant to the ISM and Solar System icy bodies such as comets, a condensed CH3OH:NH3â = 1:1 ice mixture was UV irradiated at ˜80 K. The molecular constituents of the nonvolatile organic residue that remained at room temperature were separated by capillary gas chromatography and identified by mass spectrometry. Urea, glycolic acid, and glycerol were detected in this residue, as well as hydroxyacetamide, glycerolic acid, and glycerol amide. These organics are interesting target molecules to be searched for in space. Finally, tentative mechanisms of formation for these compounds under interstellar/pre-cometary conditions are proposed.

From Molecules to Life: Quantifying the Complexity of Chemical and Biological Systems in the Universe.

PubMed

Böttcher, Thomas

2018-01-01

Life is a complex phenomenon and much research has been devoted to both understanding its origins from prebiotic chemistry and discovering life beyond Earth. Yet, it has remained elusive how to quantify this complexity and how to compare chemical and biological units on one common scale. Here, a mathematical description of molecular complexity was applied allowing to quantitatively assess complexity of chemical structures. This in combination with the orthogonal measure of information complexity resulted in a two-dimensional complexity space ranging over the entire spectrum from molecules to organisms. Entities with a certain level of information complexity directly require a functionally complex mechanism for their production or replication and are hence indicative for life-like systems. In order to describe entities combining molecular and information complexity, the term biogenic unit was introduced. Exemplified biogenic unit complexities were calculated for ribozymes, protein enzymes, multimeric protein complexes, and even an entire virus particle. Complexities of prokaryotic and eukaryotic cells, as well as multicellular organisms, were estimated. Thereby distinct evolutionary stages in complexity space were identified. The here developed approach to compare the complexity of biogenic units allows for the first time to address the gradual characteristics of prebiotic and life-like systems without the need for a definition of life. This operational concept may guide our search for life in the Universe, and it may direct the investigations of prebiotic trajectories that lead towards the evolution of complexity at the origins of life.

Observations and Laboratory Data of Planetary Organics

NASA Technical Reports Server (NTRS)

Roush, Ted L.

2002-01-01

Many efforts are underway to search for evidence of prebiotic materials in the outer solar system. Current and planned Mars missions obtain remote sensing observations that can be used to address the potential presence of prebiotic materials. Additional missions to, and continuing earth-based observations of, more distant solar system objects will also provide remote sensing observations that can be used to address the potential presence of prebiotic materials. I will present an overview of on-going observations, associated laboratory investigations of candidate materials, and theoretical modeling of observational data. In the past the room temperature reflectance spectra of many residues created from HC-bearing gases and solids have been reported. The results of an investigation of what effect temperatures more representative of outer solar system surfaces (50-140K) have on the reflectance spectra of these residues, and the associated interpretations, will be presented. The relatively organic-rich Tagish Lake Meteorite has been suggested as a spectral analog for Dtype asteroids. Using a new approach that relies upon iterative use of Hapke theory and Kraniers-Kronig analysis the optical constants of TLM were estimated. The approach and results of the analysis will be presented. Use of optical constants in scattering theories, such as the Hapke theory, provide the ability to determine quantitative estimates of the relative abundances and grain sizes of candidate surface components. This approach has been applied to interpret the reflectance spectra of several outer solar system surfaces. A summary will be provided describing the results of such modeling efforts.

The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.

PubMed

Saladino, Raffaele; Barontini, Maurizio; Cossetti, Cristina; Di Mauro, Ernesto; Crestini, Claudia

2011-08-01

The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.

Applications of prebiotics in food industry: A review.

PubMed

Singla, Vinti; Chakkaravarthi, S

2017-12-01

Benefits of prebiotics for stimulating a healthy intestinal tract are well known. From suppression of pathogens to proliferation of indigenous bacteria of intestines, prebiotics have it all. Since the research on the scope of prebiotics is expanding, new applications are coming up every day thus upgrading the choices consumer has for a healthy living. Incorporation of prebiotics in a wide range of products that food industry offers on shelf is an innovative way to replace fat and sugars along with enhancing the mouthfeel by providing better tongue lubrication. In some cases, the thermal stability of the product is improved along with other sensory, textural and physiological benefits. This paper gives an overview of the various prebiotics available from different sources and their applications in various segments of food industry, notably dairy, beverage, processed fruit-vegetable, bakery, confectionary, extruded snack, sweetener, infant formula, pet food and livestock industry. The effects observed on addition of various prebiotics are also elaborated.

Synthesis of a Fucosylated Trisaccharide Via Transglycosylation by α-L-Fucosidase from Thermotoga maritima.

PubMed

Guzmán-Rodríguez, Francisco; Alatorre-Santamaría, Sergio; Gómez-Ruiz, Lorena; Rodríguez-Serrano, Gabriela; García-Garibay, Mariano; Cruz-Guerrero, Alma

2018-05-02

Fucosylated oligosaccharides, such as 2'-fucosyllactose in human milk, have important biological functions such as prebiotics and preventing infection. In this work, the effect of an acceptor substrate (lactose) and the donor substrate 4-nitrophenyl-α-L-fucopyranoside (pNP-Fuc) on the synthesis of a fucosylated trisaccharide was studied in a transglycosylation reaction using α-L-fucosidase from Thermotoga maritima. Conducting a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), it was demonstrated that synthesized oligosaccharide corresponded to a fucosylated trisaccharide, and high-performance liquid chromatography (HPLC) of the hydrolyzed compound confirmed it was fucosyllactose. As the concentration of the acceptor substrate increased, the concentration and synthesis rate of the fucosylated trisaccharide also increased, and the highest concentration obtained was 0.883 mM (25.2% yield) when using the higher initial lactose concentration (584 mM). Furthermore, the lower donor/acceptor ratio had the highest synthesis, so at the molar ratio of 0.001, a concentration of 0.286 mM was obtained (32.5% yield).

A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites

NASA Technical Reports Server (NTRS)

Burton, Aaron S.; Elsila, Jamie E.; Callahan, Michael P.; Martin, Mildred G.; Glavin, Daniel P.; Johnson, Natasha M.; Dworkin, Jason P.

2012-01-01

Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. We report the detection of extraterrestrial amino acids in thermally-altered type 3 CV and CO carbonaceous chondrites and ureilites recovered from Antarctica. The amino acid concentrations of the thirteen Antarctic meteorites were generally less abundant than in more amino acid-rich CI, CM, and CR carbonaceous chondrites that experienced much lower temperature aqueous alteration on their parent bodies. In contrast to low-temperature aqueously-altered meteorites that show complete structural diversity in amino acids formed predominantly by Strecker-cyanohydrin synthesis, the thermally-altered meteorites studied here are dominated by small, straight-chain, amine terminal (n-omega-amino) amino acids that are not consistent with Strecker formation. The carbon isotopic ratios of two extraterrestrial n-omega-amino acids measured in one of the CV chondrites are consistent with C-13-depletions observed previously in hydrocarbons produced by Fischer-Tropsch type reactions. The predominance of n-omega-amino acid isomers in thermally-altered meteorites hints at cosmochemical mechanisms for the preferential formation and preservation of a small subset of the possible amino acids.

A Critical Look at Prebiotics Within the Dietary Fiber Concept.

PubMed

Verspreet, Joran; Damen, Bram; Broekaert, Willem F; Verbeke, Kristin; Delcour, Jan A; Courtin, Christophe M

2016-01-01

This article reviews the current knowledge of the health effects of dietary fiber and prebiotics and establishes the position of prebiotics within the broader context of dietary fiber. Although the positive health effects of specific fibers on defecation, reduction of postprandial glycemic response, and maintenance of normal blood cholesterol levels are generally accepted, other presumed health benefits of dietary fibers are still debated. There is evidence that specific dietary fibers improve the integrity of the epithelial layer of the intestines, increase the resistance against pathogenic colonization, reduce the risk of developing colorectal cancer, increase mineral absorption, and have a positive impact on the immune system, but these effects are neither generally acknowledged nor completely understood. Many of the latter effects are thought to be particularly elicited by prebiotics. Although the prebiotic concept evolved significantly during the past two decades, the line between prebiotics and nonprebiotic dietary fiber remains vague. Nevertheless, scientific evidence demonstrating the health-promoting potential of prebiotics continues to accumulate and suggests that prebiotic fibers have their rightful place in a healthy diet.

Prebiotics increase heme iron bioavailability and do not affect non-heme iron bioavailability in humans.

PubMed

Weinborn, Valerie; Valenzuela, Carolina; Olivares, Manuel; Arredondo, Miguel; Weill, Ricardo; Pizarro, Fernando

2017-05-24

The aim of this study was to establish the effect of a prebiotic mix on heme and non-heme iron (Fe) bioavailability in humans. To this purpose, twenty-four healthy women were randomized into one of two study groups. One group ate one yogurt per day for 12 days with a prebiotic mix (prebiotic group) and the other group received the same yogurt but without the prebiotic mix (control group). Before and after the intake period, the subjects participated in Fe absorption studies. These studies used 55 Fe and 59 Fe radioactive isotopes as markers of heme Fe and non-heme Fe, respectively, and Fe absorption was measured by the incorporation of radioactive Fe into erythrocytes. The results showed that there were no significant differences in heme and non-heme Fe bioavailability in the control group. Heme Fe bioavailability of the prebiotic group increased significantly by 56% post-prebiotic intake. There were no significant differences in non-heme Fe bioavailability in this group. We concluded that daily consumption of a prebiotic mix increases heme Fe bioavailability and does not affect non-heme iron bioavailability.

Cholesterol-Lowering Effects of Probiotics and Prebiotics: A Review of in Vivo and in Vitro Findings

PubMed Central

Ooi, Lay-Gaik; Liong, Min-Tze

2010-01-01

Probiotics are live microorganisms that promote health benefits upon consumption, while prebiotics are nondigestible food ingredients that selectively stimulate the growth of beneficial microorganisms in the gastrointestinal tract. Probiotics and/or prebiotics could be used as alternative supplements to exert health benefits, including cholesterol-lowering effects on humans. Past in vivo studies showed that the administration of probiotics and/or prebiotics are effective in improving lipid profiles, including the reduction of serum/plasma total cholesterol, LDL-cholesterol and triglycerides or increment of HDL-cholesterol. However, other past studies have also shown that probiotics and prebiotics had insignificant effects on lipid profiles, disputing the hypocholesterolemic claim. Additionally, little information is available on the effective dosage of probiotics and prebiotics needed to exert hypocholesterolemic effects. Probiotics and prebiotics have been suggested to reduce cholesterol via various mechanisms. However, more clinical evidence is needed to strengthen these proposals. Safety issues regarding probiotics and/or prebiotics have also been raised despite their long history of safe use. Although probiotic-mediated infections are rare, several cases of systemic infections caused by probiotics have been reported and the issue of antibiotic resistance has sparked much debate. Prebiotics, classified as food ingredients, are generally considered safe, but overconsumption could cause intestinal discomfort. Conscientious prescription of probiotics and/or prebiotics is crucial, especially when administering to specific high risk groups such as infants, the elderly and the immuno-compromised. PMID:20640165

The effect on the blood lipid profile of soy foods combined with a prebiotic: a randomized controlled trial.

PubMed

Wong, Julia M W; Kendall, Cyril W C; de Souza, Russell; Emam, Azadeh; Marchie, Augustine; Vidgen, Ed; Holmes, Candice; Jenkins, David J A

2010-09-01

The value of soy protein as part of the cholesterol-lowering diet has been questioned by recent studies. The apparent lack of effect may relate to the absence of dietary factors that increase colonic fermentation and potentiate the cholesterol-lowering effect of soy. Therefore, unabsorbable carbohydrates (prebiotics) were added to the diet with the aim of increasing colonic fermentation and so potentially increasing the hypocholesterolemic effect of soy. Twenty-three hyperlipidemic adults (11 male, 12 female; 58 +/- 7 years old; low-density lipoprotein cholesterol [LDL-C], 4.18 +/- 0.58 mmol/L) completed three 4-week diet intervention phases-a low-fat dairy diet and 10 g/d prebiotic (oligofructose-enriched inulin, a fermentable carbohydrate), a soy food-containing diet (30 g/d soy protein, 61 mg/d isoflavones from soy foods) and 10 g/d placebo (maltodextrin), and a soy food-containing diet with 10 g/d prebiotic--in a randomized controlled crossover study. Intake of soy plus prebiotic resulted in greater reductions in LDL-C (-0.18 +/- 0.07 mmol/L, P = .042) and in ratio of LDL-C to high-density lipoprotein cholesterol (-0.28 +/- 0.11, P = .041) compared with prebiotic. In addition, high-density lipoprotein cholesterol was significantly increased on soy plus prebiotic compared with prebiotic (0.06 +/- 0.02 mmol/L, P = .029). Differences in bifidobacteria, total anaerobes, aerobes, and breath hydrogen did not reach significance. Soy foods in conjunction with a prebiotic resulted in significant improvements in the lipid profile, not seen when either prebiotic or soy alone was taken. Coingestion of a prebiotic may potentiate the effectiveness of soy foods as part of the dietary strategy to lower serum cholesterol. Copyright 2010 Elsevier Inc. All rights reserved.

Influence of different prebiotics and mode of their administration on broiler chicken performance.

PubMed

Bednarczyk, M; Stadnicka, K; Kozłowska, I; Abiuso, C; Tavaniello, S; Dankowiakowska, A; Sławińska, A; Maiorano, G

2016-08-01

In the post-antibiotics era, prebiotics are proposed as alternatives to antibiotic growth promoters in poultry production. The goal of this study was to compare in ovo method of prebiotic delivery with in-water supplementation and with both methods combined (in ovo+in-water) in broiler chickens. Two trials were conducted. Trial 1 was carried out to optimize the doses of two prebiotics, DN (DiNovo®, extract of beta-glucans) and BI (Bi2tos, trans-galactooligosaccharides), for in ovo delivery. The estimated parameters were hatchability and bacteriological status of the newly hatched chicks. Prebiotics were dissolved in 0.2 ml of physiological saline, at the doses: 0.18, 0.88, 3.5 and 7.0 mg/embryo; control group (C) was injected in ovo with 0.2 ml of physiological saline. Trial 2 was conducted to evaluate effects of different prebiotics (DN, BI and raffinose family oligosaccharides (RFO)) delivered in ovo, in-water and in a combined way (in ovo+in-water) on broiler chickens performance. The results of the Trial 1 indicated that the optimal dose of DN and BI prebiotics delivered in ovo, that did not reduce chicks' hatchability, was 0.88 mg/embryo (DN) and 3.5 mg/embryo (BI). Both prebiotics numerically increased number of lactobacilli and bifidobacteria in chicken feces (P>0.05). In Trial 2, all prebiotics (DN, BI and RFO) significantly increased BW gain compared with the C group (P<0.05), especially during the first 21 days of life. However, feed intake and feed conversion ratio were increased upon prebiotics delivery irrespective of method used. Injection of prebiotics in ovo combined with in-water supplementation did not express synergistic effects on broilers performance compared with in ovo injection only. Taken together, those results confirm that single in ovo prebiotics injection into the chicken embryo can successfully replace prolonged in-water supplementation post hatching.

Prebiotic Lipidic Amphiphiles and Condensing Agents on the Early Earth

PubMed Central

Fiore, Michele; Strazewski, Peter

2016-01-01

It is still uncertain how the first minimal cellular systems evolved to the complexity required for life to begin, but it is obvious that the role of amphiphilic compounds in the origin of life is one of huge relevance. Over the last four decades a number of studies have demonstrated how amphiphilic molecules can be synthesized under plausibly prebiotic conditions. The majority of these experiments also gave evidence for the ability of so formed amphiphiles to assemble in closed membranes of vesicles that, in principle, could have compartmented first biological processes on early Earth, including the emergence of self-replicating systems. For a competitive selection of the best performing molecular replicators to become operative, some kind of bounded units capable of harboring them are indispensable. Without the competition between dynamic populations of different compartments, life itself could not be distinguished from an otherwise disparate array or network of molecular interactions. In this review, we describe experiments that demonstrate how different prebiotically-available building blocks can become precursors of phospholipids that form vesicles. We discuss the experimental conditions that resemble plausibly those of the early Earth (or elsewhere) and consider the analytical methods that were used to characterize synthetic products. Two brief sections focus on phosphorylating agents, catalysts and coupling agents with particular attention given to their geochemical context. In Section 5, we describe how condensing agents such as cyanamide and urea can promote the abiotic synthesis of phospholipids. We conclude the review by reflecting on future studies of phospholipid compartments, particularly, on evolvable chemical systems that include giant vesicles composed of different lipidic amphiphiles. PMID:27043635

Aqueous processing of organic compounds in carbonaceous asteroids

NASA Astrophysics Data System (ADS)

Trigo-Rodríguez, Josep Maria; Rimola, Albert; Martins, Zita

2015-04-01

There is growing evidence pointing towards a prebiotic synthesis of complex organic species in water-rich undifferentiated bodies. For instance, clays have been found to be associated with complex organic compounds (Pearson et al. 2002; Garvie & Buseck 2007; Arteaga et al. 2010), whereas theoretical calculations have studied the interaction between the organic species and surface minerals (Rimola et al., 2013) as well as surface-induced reactions (Rimola at al. 2007). Now, we are using more detailed analytical techniques to study the possible processing of organic molecules associated with the mild aqueous alteration in CR, CM and CI chondrites. To learn more about these processes we are studying carbonaceous chondrites at Ultra High-Resolution Transmission Electron Microscopy (UHR-TEM). We are particularly interested in the relationship between organics and clay minerals in carbonaceous chondrites (CCs) matrixes (Trigo-Rodríguez et al. 2014, 2015).We want to address two goals: i) identifying the chemical steps in which the organic molecules could have increased their complexity (i.e., surface interaction and catalysis); and ii) studying if the organic matter present in CCs experienced significant processing concomitant to the formation of clays and other minerals at the time in which these planetary bodies experienced aqueous alteration. Here, these two points are preliminarily explored combing experimental results with theoretical calculations based on accurate quantum mechanical methods. References Arteaga O, Canillas A, Crusats J, El-Hachemi Z, Jellison GE, Llorca J, Ribó JM (2010) Chiral biases in solids by effect of shear gradients: a speculation on the deterministic origin of biological homochirality. Orig Life Evol Biosph 40:27-40. Garvie LAJ, Buseck PR (2007) Prebiotic carbon in clays from Orgueil and Ivuna (CI) and Tagish lake (C2 ungrouped) meteorites. Meteorit Planet Sci 42:2111-2117. Pearson VK, Sephton MA, Kearsley AT, Bland AP, Franchi IA, Gilmour A (2002) Clay mineral-organic matter relationships in the early solar system. Meteorit Planet Sci 37:1829-1833. Rimola A, Costa D, Sodupe M, Lambert JF, Ugliengo P (2013) Silica surface features and their role in the adsorption of biomolecules: computational modeling and experiments. Chem Rev 113:4216-4313. Rimola A, Sodupe M, Ugliengo P (2007) Aluminosilicate as promoters for peptide bond formation: an assessment of Bernal's hypothesis by ab initio methods. J Am Chem soc 129:8333-8344 Trigo-Rodríguez JM, Moyano-Cambero CE, Llorca J, Formasier S, Barucci MA, Belskaya I, Martins Z, Rivkin AS, Dotto E, Madiedo JM, Alonso-Azcárate J (2014) UV to far-IR reflectance spectra of carbonaceous chondrites - I. Implications for remote characterization of dark primitive asteroids targeted by sample-return missions. Mon Not R Astron Soc 437:227-240. Trigo-Rodríguez JM, Alonso-Azcárate J, Abad MM, Lee MR (2015) Ultra high resolution Transmission Electron Microscopy of matrix mineral grains in CM chondrites: preaccretionary or parent body aqueous processing? LPI constribution, 46th LPSC, abstract #1198.

Nucleobases and Prebiotic Molecules in Organic Residues Produced from the Ultraviolet Photo-Irradiation of Pyrimidine in NH3 and H2O+NH3 Ices

NASA Technical Reports Server (NTRS)

Nuevo, Michel; Milam, Stefanie N.; Sandford, Scott

2012-01-01

Although not yet identified in the interstellar medium (ISM), N-heterocycles including nucleobases the information subunits of DNA and RNA are present in carbonaceous chondrites, which indicates that molecules of biological interest can be formed in non-terrestrial environments via abiotic pathways. Recent laboratory experiments and ab-initio calculations have already shown that the irradiation of pyrimidine in pure H2O ices leads to the formation of a suite of oxidized pyrimidine derivatives, including the nucleobase uracil. In the present work, NH3:pyrimidine and H2O:NH3:pyrimidine ice mixtures with different relative proportions were irradiated with UV photons under astrophysically relevant conditions. Liquid- and gas-chromatography analysis of the resulting organic residues has led to the detection of the nucleobases uracil and cytosine, as well as other species of prebiotic interest such as urea and small amino acids. The presence of these molecules in organic residues formed under abiotic conditions supports scenarios in which extraterrestrial organics that formed in space and were subsequently delivered to telluric planets via comets and meteorites could have contributed to the inventory of molecules that triggered the first biological reactions on their surfaces.

Cost-effectiveness model for a specific mixture of prebiotics in The Netherlands.

PubMed

Lenoir-Wijnkoop, I; van Aalderen, W M C; Boehm, G; Klaassen, D; Sprikkelman, A B; Nuijten, M J C

2012-02-01

The objective of this study was to assess the cost-effectiveness of the use of prebiotics for the primary prevention of atopic dermatitis in The Netherlands. A model was constructed using decision analytical techniques. The model was developed to estimate the health economic impact of prebiotic preventive disease management of atopic dermatitis. Data sources used include published literature, clinical trials and official price/tariff lists and national population statistics. The comparator was no supplementation with prebiotics. The primary perspective for conducting the economic evaluation was based on the situation in The Netherlands in 2009. The results show that the use of prebiotics infant formula (IMMUNOFORTIS(®)) leads to an additional cost of € 51 and an increase in Quality Adjusted Life Years (QALY) of 0.108, when compared with no prebiotics. Consequently, the use of infant formula with a specific mixture of prebiotics results in an incremental cost-effectiveness ratio (ICER) of € 472. The sensitivity analyses show that the ICER remains in all analyses far below the threshold of € 20,000/QALY. This study shows that the favourable health benefit of the use of a specific mixture of prebiotics results in positive short- and long-term health economic benefits. In addition, this study demonstrates that the use of infant formula with a specific mixture of prebiotics is a highly cost-effective way of preventing atopic dermatitis in The Netherlands.

Prebiotics as a modulator of gut microbiota in paediatric obesity.

PubMed

Nicolucci, A C; Reimer, R A

2017-08-01

This review highlights our current understanding of the role of gut microbiota in paediatric obesity and the potential role for dietary manipulation of the gut microbiota with prebiotics in managing paediatric obesity. The aetiology of obesity is multifactorial and is now known to include microbial dysbiosis in the gut. Prebiotics are non-digestible carbohydrates which selectively modulate the number and/or composition of gut microbes. The goal of prebiotic consumption is to restore symbiosis and thereby confer health benefits to the host. There is convincing evidence that prebiotics can reduce adiposity and improve metabolic health in preclinical rodent models. Furthermore, there are several clinical trials in adult humans highlighting metabolic and appetite-regulating benefits of prebiotics. In paediatric obesity, however, there are very limited data regarding the potential role of prebiotics as a dietary intervention for obesity management. As the prevalence of paediatric obesity and obesity-associated comorbidities increases globally, interventions that target the progression of obesity from an early age are essential in slowing the obesity epidemic. This review emphasizes the need for further research assessing the role of prebiotics, particularly as an intervention in effectively managing paediatric obesity. © 2016 World Obesity Federation.

Prebiotics and gut microbiota in chickens.

PubMed

Pourabedin, Mohsen; Zhao, Xin

2015-08-01

Prebiotics are non-digestible feed ingredients that are metabolized by specific members of intestinal microbiota and provide health benefits for the host. Fermentable oligosaccharides are best known prebiotics that have received increasing attention in poultry production. They act through diverse mechanisms, such as providing nutrients, preventing pathogen adhesion to host cells, interacting with host immune systems and affecting gut morphological structure, all presumably through modulation of intestinal microbiota. Currently, fructooligosaccharides, inulin and mannanoligosaccharides have shown promising results while other prebiotic candidates such as xylooligosaccharides are still at an early development stage. Despite a growing body of evidence reporting health benefits of prebiotics in chickens, very limited studies have been conducted to directly link health improvements to prebiotic-dependent changes in the gut microbiota. This article visits the current knowledge of the chicken gastrointestinal microbiota and reviews most recent publications related to the roles played by prebiotics in modulation of the gut microbiota and immune functions. Progress in this field will help us better understand how the gut microbiota contributes to poultry health and productivity, and support the development of new prebiotic products as an alternative to in-feed antibiotics. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Prebiotics as functional food ingredients preventing diet-related diseases.

PubMed

Florowska, A; Krygier, K; Florowski, T; Dłużewska, E

2016-05-18

This paper reviews the potential of prebiotic-containing foods in the prevention or postponement of certain diet-related diseases, such as cardiovascular diseases with hypercholesterolemia, osteoporosis, diabetes, gastrointestinal infections and gut inflammation. Also the data on prebiotics as food ingredients and their impact on food product quality are presented. Prebiotics are short chain carbohydrates that are resistant to the digestion process in the upper part of the digestive system, are not absorbed in any segment of the gastrointestinal system, and finally are selectively fermented by specific genera of colonic bacteria. The mechanisms of the beneficial impacts of prebiotics on human health are very difficult to specify directly, because their health-promoting functions are related to fermentation by intestinal microflora. The impact of prebiotics on diet-related diseases in many ways also depends on the products of their fermentation. Prebiotics as functional food ingredients also have an impact on the quality of food products, due to their textural and gelling properties. Prebiotics as food additives can be very valuable in the creation of functional food aimed at preventing or postponing many diet-related diseases. They additionally have beneficial technological properties which improve the quality of food products.

Non-digestible oligosaccharides directly regulate host kinome to modulate host inflammatory responses without alterations in the gut microbiota.

PubMed

Wu, Richard Y; Määttänen, Pekka; Napper, Scott; Scruten, Erin; Li, Bo; Koike, Yuhki; Johnson-Henry, Kathene C; Pierro, Agostino; Rossi, Laura; Botts, Steven R; Surette, Michael G; Sherman, Philip M

2017-10-10

Prebiotics are non-digestible food ingredients that enhance the growth of certain microbes within the gut microbiota. Prebiotic consumption generates immune-modulatory effects that are traditionally thought to reflect microbial interactions within the gut. However, recent evidence suggests they may also impart direct microbe-independent effects on the host, though the mechanisms of which are currently unclear. Kinome arrays were used to profile the host intestinal signaling responses to prebiotic exposures in the absence of microbes. Identified pathways were functionally validated in Caco-2Bbe1 intestinal cell line and in vivo model of murine endotoxemia. We found that prebiotics directly regulate host mucosal signaling to alter response to bacterial infection. Intestinal epithelial cells (IECs) exposed to prebiotics are hyporesponsive to pathogen-induced mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) activations, and have a kinome profile distinct from non-treated cells pertaining to multiple innate immune signaling pathways. Consistent with this finding, mice orally gavaged with prebiotics showed dampened inflammatory response to lipopolysaccharide (LPS) without alterations in the gut microbiota. These findings provide molecular mechanisms of direct host-prebiotic interactions to support prebiotics as potent modulators of host inflammation.

Schreibersite: an effective catalyst in the formose reaction network

NASA Astrophysics Data System (ADS)

Pallmann, S.; Šteflová (neé Svobodová, J.; Haas, M.; Lamour, S.; Henß, A.; Trapp, O.

2018-05-01

We report on the ability of the meteoritic material schreibersite to catalyze the generation of higher sugars from simple carbohydrates in the formose reaction network. Since the analysis of carbonaceous meteorites like the Murchison meteorite it has become generally accepted that a substantial amount of organic material has been delivered to the early earth and, therefore, ought to be considered in scenarios for the origin(s) of life. Also for the open question of accessible phosphorus sources, an extraterrestrial material called schreibersite has been identified that is capable of releasing soluble and reactive phosphorus oxyanions that would react with organics to form for instance nucleotides and membrane associated molecules. We have reinvestigated this material using capillary electrophoresis to monitor its corrosion process in water and probed its ability to phosphorylate a wide range of organics. Although showing a poor reactivity of schreibersite, we have found that the material catalyzes the aldol reaction of small carbohydrates forming larger sugar molecules. This reaction in the formose reaction network is a prebiotically likely route to biologically relevant sugars. The results of our study present one of the first instances of connecting extraterrestrial material to prebiotic chemistry on the early earth.

Prebiotics: Definition and protective mechanisms.

PubMed

Valcheva, Rosica; Dieleman, Levinus A

2016-02-01

The increase in chronic metabolic and immunologic disorders in the modern society is linked to major changes in the dietary patterns. These chronic conditions are associated with intestinal microbiota dysbiosis where important groups of carbohydrate fermenting, short-chain fatty acids-producing bacteria are reduced. Dietary prebiotics are defined as a selectively fermented ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health. Application of prebiotics may then restore the gut microbiota diversity and activity. Unlike the previously accepted prebiotics definition, where a limited number of bacterial species are involved in the prebiotic activity, new data from community-wide microbiome analysis demonstrated a broader affect of the prebiotics on the intestinal microbiota. These new findings require a revision of the current definition. In addition, prebiotics may exert immunomodulatory effects through microbiota-independent mechanisms that will require future investigations involving germ-free animal disease models. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dimerization in Highly Concentrated Solutions of Phosphoimidazolide Activated Monomucleotides

NASA Astrophysics Data System (ADS)

Kanavarioti, Anastassia

1997-08-01

Phosphoimidazolide activated ribomononucleotides (*pN) are useful substrates for the non-enzymatic synthesis of polynucleotides. However, dilute neutral aqueous solutions of *pN typically yield small amounts of dimers and traces of polymers; most of *pN hydrolyzes to yield nucleoside 5'-monophosphate. Here we report the self-condensation of nucleoside 5'-phosphate 2-methylimidazolide (2-MeImpN with N = cytidine, uridine or guanosine) in the presence of Mg2+ in concentrated solutions, such as might have been found in an evaporating lagoon on prebiotic Earth. The product distribution indicates that oligomerization is favored at the expense of hydrolysis. At 1.0 M, 2-MeImpU and 2-MeImpC produce about 65% of oligomers including 4% of the 3',5'-linked dimer. Examination of the product distribution of the three isomeric dimers in a self-condensation allows identification of reaction pathways that lead to dimer formation. Condensations in a concentrated mixture of all three nucleotides (U,C,G mixtures) is made possible by the enhanced solubility of 2-MeImpG in such mixtures. Although percent yield of internucleotide linked dimers is enhanced as a function of initial monomer concentration, pyrophosphate dimer yields remain practically unchanged at about 20% for 2-MeImpU, 16% for 2-MeImpC and 25% of the total pyrophosphate in the U,C,G mixtures. The efficiency by which oligomers are produced in these concentrated solutions makes the evaporating lagoon scenario a potentially interesting medium for the prebiotic synthesis of dimers and short RNAs.

Isomeric effects on the self-assembly of a plausible prebiotic nucleoside analogue: A theoretical study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vallejo, Emmanuel; Fuentes-Cabrera, Miguel; Sumpter, Bobby G.

For this study, the self-assembly properties of N(9)-(2,3-dihydroxypropyl adenine) (DHPA), a plausible prebiotic nucleoside analogue of adenosine, were investigated using density functional theory. Two different isomers were considered, and it is found that while both isomers can form a variety of structures, including chains, one of them is also able to form cages and helixes. When these results were put in the context of substrate supported molecular self-assembly, it is concluded that gas-phase self-assembly studies that consider isomer identity and composition not only can aid interpreting the experimental results, but also reveal structures that might be overlooked otherwise. In particular,more » this study suggest that a double-helical structure made of DHPA molecules which could have implications in prebiotic chemistry and nanotechnology, is stable even at room temperature. For example electrical properties (energy gap of 4.52eV) and a giant permanent electrical dipole moment (49.22 Debye) were found in our larger double-helical structure (3.7 nm) formed by 14 DHPA molecules. Lastly, the former properties could be convenient for construction of organic dielectric-based devices.« less

Isomeric effects on the self-assembly of a plausible prebiotic nucleoside analogue: A theoretical study

DOE PAGES

Vallejo, Emmanuel; Fuentes-Cabrera, Miguel; Sumpter, Bobby G.; ...

2016-10-22

For this study, the self-assembly properties of N(9)-(2,3-dihydroxypropyl adenine) (DHPA), a plausible prebiotic nucleoside analogue of adenosine, were investigated using density functional theory. Two different isomers were considered, and it is found that while both isomers can form a variety of structures, including chains, one of them is also able to form cages and helixes. When these results were put in the context of substrate supported molecular self-assembly, it is concluded that gas-phase self-assembly studies that consider isomer identity and composition not only can aid interpreting the experimental results, but also reveal structures that might be overlooked otherwise. In particular,more » this study suggest that a double-helical structure made of DHPA molecules which could have implications in prebiotic chemistry and nanotechnology, is stable even at room temperature. For example electrical properties (energy gap of 4.52eV) and a giant permanent electrical dipole moment (49.22 Debye) were found in our larger double-helical structure (3.7 nm) formed by 14 DHPA molecules. Lastly, the former properties could be convenient for construction of organic dielectric-based devices.« less

Modulation of the gut microbiota by prebiotic fibres and bacteriocins

PubMed Central

Umu, Özgün C. O.; Rudi, Knut; Diep, Dzung B.

2017-01-01

ABSTRACT The gut microbiota is considered an organ that co-develops with the host throughout its life. The composition and metabolic activities of the gut microbiota are subject to a complex interplay between the host genetics and environmental factors, such as lifestyle, diet, stress and antimicrobials. It is evident that certain prebiotics, and antimicrobials produced by lactic acid bacteria (LAB), can shape the composition of the gut microbiota and its metabolic activities to promote host health and/or prevent diseases. In this review, we aim to give an overview of the impact of prebiotic fibres, and bacteriocins from LAB, on the gut microbiota and its activities, which affect the physiology and health of the host. These represent two different mechanisms in modulating the gut microbiota, the first involving exploitative competition by which the growth of beneficial bacteria is promoted and the latter involving interference competition by which the growth of pathogens and other unwanted bacteria is prevented. For interference competition in the gut, bacteriocins offer special advantages over traditional antibiotics, in that they can be designed to act towards specific unwanted bacteria and other pathogens, without any remarkable collateral effects on beneficial microbes sharing the same niche. PMID:28959178

Understanding Organics in Meteorites and the Pre-Biotic Environment

NASA Technical Reports Server (NTRS)

Zare, Richard N.

2003-01-01

(1) Refinement of the analytic capabilities of our experiment via characterization of molecule-specific response and the effects upon analysis of the type of sample under investigation; (2) Measurement of polycyclic aromatic hydrocarbons (PAHs) with high sensitivity and spatial resolution within extraterrestrial samples; (3) Investigation of the interstellar reactions of PAHs via the analysis of species formed in systems modeling dust grains and ices; (4) Investigations into the potential role of PAHs in prebiotic and early biotic chemistry via photoreactions of PAHs under simulated prebiotic Earth conditions. To meet these objectives, we use microprobe laser-desorption, laser-ionization mass spectrometry (MuL(exp 2)MS), which is a sensitive, selective, and spatially resolved technique for detection of aromatic compounds. Appendix A presents a description of the MuL(exp 2)MS technique. The initial grant proposal was for a three-year funding period, while the award was given for a one-year interim period. Because of this change in time period, emphasis was shifted from the first research goal, which was more development-oriented, in order to focus more on the other analysis-oriented goals. The progress made on each of the four research areas is given below.

Molecular assessment of the fecal microbiota in healthy cats and dogs before and during supplementation with fructo-oligosaccharides (FOS) and inulin using high-throughput 454-pyrosequencing

PubMed Central

Barcenas-Walls, Jose R.; Suchodolski, Jan S.; Steiner, Jörg M.

2017-01-01

Prebiotics are selectively fermentable dietary compounds that result in changes in the composition and/or activity of the intestinal microbiota, thus conferring benefits upon host health. In veterinary medicine, commercially available products containing prebiotics have not been well studied with regard to the changes they trigger on the composition of the gut microbiota. This study evaluated the effect of a commercially available nutraceutical containing fructo-oligosaccharides (FOS) and inulin on the fecal microbiota of healthy cats and dogs when administered for 16 days. Fecal samples were collected at two time points before and at two time points during prebiotic administration. Total genomic DNA was obtained from fecal samples and 454-pyrosequencing was used for 16S rRNA gene bacterial profiling. The linear discriminant analysis (LDA) effect size (LEfSe) method was used for detecting bacterial taxa that may respond (i.e., increase or decrease in its relative abundance) to prebiotic administration. Prebiotic administration was associated with a good acceptance and no side effects (e.g., diarrhea) were reported by the owners. A low dose of prebiotics (50 mL total regardless of body weight with the end product containing 0.45% of prebiotics) revealed a lower abundance of Gammaproteobacteria and a higher abundance of Veillonellaceae during prebiotic administration in cats, while Staphylococcaceae showed a higher abundance during prebiotic administration in dogs. These differences were not sufficient to separate bacterial communities as shown by analysis of weighted UniFrac distance metrics. A predictive approach of the fecal bacterial metagenome using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) also did not reveal differences between the period before and during prebiotic administration. A second trial using a higher dose of prebiotics (3.2 mL/kg body weight with the end product containing 3.1% of prebiotics) was tested in dogs and revealed a lower abundance of Dorea (family Clostridiaceae) and a higher abundance of Megamonas and other (unknown) members of Veillonellaceae during prebiotic administration. Again, these changes were not sufficient to separate bacterial communities or predicted metabolic profiles according to treatment. A closer analysis of bacterial communities at all time-points revealed highly individualized patterns of variation. This study shows a high interindividual variation of fecal bacterial communities from pet cats and dogs, that these communities are relatively stable over time, and that some of this variation can be attributable to prebiotic administration, a phenomenon that may be affected by the amount of the prebiotic administered in the formulation. This study also provides insights into the response of gut bacterial communities in pet cats and dogs during administration of commercially available products containing prebiotics. More studies are needed to explore potentially beneficial effects on host health beyond changes in bacterial communities. PMID:28439463

The Role of Probiotics and Prebiotics in Inducing Gut Immunity

PubMed Central

Vieira, Angélica T.; Teixeira, Mauro M.; Martins, Flaviano S.

2013-01-01

The gut immune system is influenced by many factors, including dietary components and commensal bacteria. Nutrients that affect gut immunity and strategies that restore a healthy gut microbial community by affecting the microbial composition are being developed as new therapeutic approaches to treat several inflammatory diseases. Although probiotics (live microorganisms) and prebiotics (food components) have shown promise as treatments for several diseases in both clinical and animal studies, an understanding of the molecular mechanisms behind the direct and indirect effects on the gut immune response will facilitate better and possibly more efficient therapy for diseases. In this review, we will first describe the concept of prebiotics, probiotics, and symbiotics and cover the most recently well-established scientific findings regarding the direct and indirect mechanisms by which these dietary approaches can influence gut immunity. Emphasis will be placed on the relationship of diet, the microbiota, and the gut immune system. Second, we will highlight recent results from our group, which suggest a new dietary manipulation that includes the use of nutrient products (organic selenium and Lithothamnium muelleri) and probiotics (Saccharomyces boulardii UFMG 905 and Bifidobacterium sp.) that can stimulate and manipulate the gut immune response, inducing intestinal homeostasis. Furthermore, the purpose of this review is to discuss and translate all of this knowledge into therapeutic strategies and into treatment for extra-intestinal compartment pathologies. We will conclude by discussing perspectives and molecular advances regarding the use of prebiotics or probiotics as new therapeutic strategies that manipulate the microbial composition and the gut immune responses of the host. PMID:24376446

Clinical trial: the effects of a trans-galactooligosaccharide prebiotic on faecal microbiota and symptoms in irritable bowel syndrome.

PubMed

Silk, D B A; Davis, A; Vulevic, J; Tzortzis, G; Gibson, G R

2009-03-01

Gut microflora-mucosal interactions may be involved in the pathogenesis of irritable bowel syndrome (IBS). To investigate the efficacy of a novel prebiotic trans-galactooligosaccharide in changing the colonic microflora and improve the symptoms in IBS sufferers. In all, 44 patients with Rome II positive IBS completed a 12-week single centre parallel crossover controlled clinical trial. Patients were randomized to receive either 3.5 g/d prebiotic, 7 g/d prebiotic or 7 g/d placebo. IBS symptoms were monitored weekly and scored according to a 7-point Likert scale. Changes in faecal microflora, stool frequency and form (Bristol stool scale) subjective global assessment (SGA), anxiety and depression and QOL scores were also monitored. The prebiotic significantly enhanced faecal bifidobacteria (3.5 g/d P < 0.005; 7 g/d P < 0.001). Placebo was without effect on the clinical parameters monitored, while the prebiotic at 3.5 g/d significantly changed stool consistency (P < 0.05), improved flatulence (P < 0.05) bloating (P < 0.05), composite score of symptoms (P < 0.05) and SGA (P < 0.05). The prebiotic at 7 g/d significantly improved SGA (P < 0.05) and anxiety scores (P < 0.05). The galactooligosaccharide acted as a prebiotic in specifically stimulating gut bifidobacteria in IBS patients and is effective in alleviating symptoms. These findings suggest that the prebiotic has potential as a therapeutic agent in IBS.

Quantum entanglement in photoactive prebiotic systems.

PubMed

Tamulis, Arvydas; Grigalavicius, Mantas

2014-06-01

This paper contains the review of quantum entanglement investigations in living systems, and in the quantum mechanically modelled photoactive prebiotic kernel systems. We define our modelled self-assembled supramolecular photoactive centres, composed of one or more sensitizer molecules, precursors of fatty acids and a number of water molecules, as a photoactive prebiotic kernel systems. We propose that life first emerged in the form of such minimal photoactive prebiotic kernel systems and later in the process of evolution these photoactive prebiotic kernel systems would have produced fatty acids and covered themselves with fatty acid envelopes to become the minimal cells of the Fatty Acid World. Specifically, we model self-assembling of photoactive prebiotic systems with observed quantum entanglement phenomena. We address the idea that quantum entanglement was important in the first stages of origins of life and evolution of the biospheres because simultaneously excite two prebiotic kernels in the system by appearance of two additional quantum entangled excited states, leading to faster growth and self-replication of minimal living cells. The quantum mechanically modelled possibility of synthesizing artificial self-reproducing quantum entangled prebiotic kernel systems and minimal cells also impacts the possibility of the most probable path of emergence of protocells on the Earth or elsewhere. We also examine the quantum entangled logic gates discovered in the modelled systems composed of two prebiotic kernels. Such logic gates may have application in the destruction of cancer cells or becoming building blocks of new forms of artificial cells including magnetically active ones.

Synergism of Saturn, Enceladus and Titan and Formation of HCNO Prebiotic Molecules

NASA Technical Reports Server (NTRS)

Sittler, Edward C.; Cooper, John F.

2011-01-01

Saturn as a system has two very exotic moons Titan and Enceladus. Titan, taking in energy from Saturn's magnetosphere, solar UV irradiation, and cosmic rays, can make HCN based molecules as discussed in earlier paper by Raulin and Owen. Space radiation effects at both moons, and as coupled by the Saturn magnetosphere, could cause an unexpected series of events potentially leading to prebiotic chemical evolution at Titan with HCNO from magnetospheric oxygen as the new ingredient. The "Old Faithful" model suggests that Enceladus, highly irradiated by Saturn magnetospheric electrons and thus having a source of chemical energy from radiolytic gas production, has episodic ejections of water vapor, carbon dioxide, and various hydrocarbons into Saturn's magnetosphere. The hydrocarbons do not survive transport through the plasma environment, but oxygen ions from Enceladus water molecules become the dominant ion species in the outer magnetosphere. At Titan, Cassini discovered that 1) keV oxygen ions, evidently from Enceladus, are bombarding Titan's upper atmosphere and 2) heavy positive and negative ions exist in significant abundances within Titan's upper atmosphere. Initial models of heavy ion formation in Titan's upper atmosphere invoked polymerization of aromatics such as benzenes and their radicals to make polycyclic aromatic hydrocarbons (PAH) , while a more recent model by Sittler et al., has raised the possibility of carbon chains forming from the polymerization of acetylene and its radicals to make fullerenes. Laboratory measurements indicate that fullerenes, which are hollow carbon shells, can trap keV oxygen ions. Clustering of the fullerenes with aerosol mixtures from PAHs and the dominant nitrogen molecules could form larger aerosols enriched in trapped oxygen. Aerosol precipitation could then convey these chemically complex structures deeper into the atmosphere and to the moon surface. Ionizing solar UV, magnetospheric electron, and galactic cosmic ray irradiation would provide further energy for processing into more complex organic forms. Further ionizing irradiation from cosmic rays deep in the atmosphere "tho lin" molecules are produced with all the molecular components present from which prebiotic organic molecules can form. This synergy of Saturn system, exogenic irradiation, and molecular processes provides a potential pathway for accumulation of prebiotic chemistry on the surface of Titan. Since fullerenes are also thought to exist in interstellar space, similar processes may also occur there to seed molecular clouds with prebiotic chemical species. We will also discuss possible future laboratory experiments that could be done to investigate fullerene formation at Titan and the trapping of oxygen in fullerenes.

Growth Studies of Probiotic Bacteria on Short Chain Glucomannan, a Potential Prebiotic Substrate

DTIC Science & Technology

2012-12-05

PROBIOTIC BACTERIA ON SHORT CHAIN GLUCOMANNAN, A POTENTIAL PREBIOTIC SUBSTRATE by Wayne S. Muller Steve Arcidiacono Adam Liebowitz Ken Racicot... PROBIOTIC BACTERIA ON SHORT CHAIN GLUCOMANNAN, A POTENTIAL PREBIOTIC SUBSTRATE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER PE...commercial prebiotic substrates. All three substrates had similar degree of polymerization (DP) of 2-9. Five probiotic bacteria were evaluated for

Thermodynamic Basis for the Emergence of Genomes during Prebiotic Evolution

DTIC Science & Technology

2012-05-01

Thermodynamic Basis for the Emergence of Genomes during Prebiotic Evolution Hyung-June Woo, Ravi Vijaya Satya, Jaques Reifman* DoD Biotechnology High...polymerases are above, near, and below a critical point, respectively. The prebiotic evolution therefore must have crossed this critical region. Over...among many potential oligomers capable of templated replication, RNAs may have evolved to form prebiotic genomes due to the value of their nonenzymatic

Prebiotics and Inflammatory Bowel Disease.

PubMed

Rasmussen, Heather E; Hamaker, Bruce R

2017-12-01

Dietary fiber, specifically prebiotics, is the primary source of energy for the gut microbiota and thus has the potential to beneficially modify microbiota composition. Prebiotics have been used in both in vitro studies and with animal models of colitis with largely positive results. Human studies are few and have been conducted with only a few select prebiotics, primarily fructan-containing fibers. Although disease activity and inflammatory markers have improved, more needs to be learned about the specific prebiotic compounds and how they can be used to best improve the gut microbiota to counter changes induced by inflammatory bowel disease. Copyright © 2017 Elsevier Inc. All rights reserved.

Prebiotic index evaluation of crude laminaran of Sargassum sp. using feces of wistar rats

NASA Astrophysics Data System (ADS)

Chamidah, A.

2018-03-01

Today, prebiotics are often added to food. This compound is a food substance which could not be digested, yet benefiting the host by selectively stimulating the growth or activity of one or more bacteria in the colon to improve the health of the host. One of the foodstuffs derived from algae, which could not be digested is laminaran (β-Glucan). The relationship between microflora with the added prebiotics was tested by measuring their prebiotic index, which is supported by total sugars and laminaran levels. The results showed that total sugar content of Laminaran Acid Extract (LAE) (9.075 %) was higher than that of Laminaran Modified Extract (LME) (7.355 %), while the laminaran level of LME (42.23 %) was higher than that of LAE (30.92 %). HPLC test result confirmed the presence of laminaran. The obtained prebiotic index values of LAE and LME were 1.29 and 2.10, respectively, with a negative index score for LAE prebiotic, yet positive one for LME in terms of probiotic from Lactobacillus group. Laminaran extract, especially LME, deserves to be regarded as a prebiotic candidate.

Carbonaceous Meteorites Contain a Wide Range of Extraterrestrial Nucleobases

NASA Technical Reports Server (NTRS)

Callahan, Michael P.; Smith, Karen E.; Cleaves, H. James, II; Ruzicka, Josef; Stern, Jennifer C.; Glavin, Daniel P.; House, Christopher H.; Dworkin, Jason P.

2011-01-01

All terrestrial organisms depend on nucleic acids (RNA and DNA), which use pyrimidine and purine nucleobases to encode genetic information. Carbon-rich meteorites may have been important sources of organic compounds required for the emergence of life on the early Earth; however, the origin and formation of nuc1eobases in meteorites has been debated for over 50 y. So far, the few nuc1eobases reported in meteorites are biologically common and lacked the structural diversity typical of other indigenous meteoritic organics. Here, we investigated the abundance and distribution of nucleobases and nucleobase analogs in formic acid extracts of 12 different meteorites by liquid chromatography-mass spectrometry. The Murchison and Lonewolf Nunataks 94102 meteorites contained a diverse suite of nucleobases, which included three unusual and terrestrially rare nucleobase analogs; purine, 2,6-diminopurine, and 6,8-diaminopurine. In a parallel experiment, we found an identical suite of nucleobases and nucleobase analogs generated in reactions of ammonium cyanide. Additionally, these nucleobase analoge were not detected above our parts-per-billion detection limits in any of the procedural blanks, control samples, a terrestrial soil sample, and an Antarctic ice sample. Our results demonstrate that the purines detected in meteorites are consistent with products of ammonium cyanide chemistry, which provides a plausible mechanism for their synthesis in the asteroid parent bodies, and strongly supports an extraterrestrial origin. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules.

Serpentinization and Synthesis: Can abiotic and biotic non-volatile organic molecules be identified in the subsurface of the Atlantis Massif?

NASA Astrophysics Data System (ADS)

Hickok, K.; Nguyen, T.; Orcutt, B.; Fruh-Green, G. L.; Wanamaker, E.; Lang, S. Q.

2016-12-01

The high concentrations of hydrogen created during serpentinization can promote the formation of abiotic organic carbon molecules such as methane, formate, short chain hydrocarbons and, in laboratory experiments, larger molecules containing up to 32 carbon atoms. Subsurface archaeal and bacterial communities can use these reduced compounds for metabolic energy. International Ocean Discovery Project Expedition 357 drilled into the Atlantis Massif with the goals of investigating carbon cycling and the presence of life in a zone of active serpentinization. The expedition recovered multiple rock lithologies including gabbros, basalts, carbonate sands, and serpentinites. A subset of these samples are being analyzed to determine if non-volatile organic molecules are produced abiotically in serpentinizing environments and to identify `hot spots' of microbial life in the subsurface. Rock samples of contrasting representative lithologies are being analyzed for the presence of n-alkanes and fatty acids. Preliminary results have so far indicated the presence of alkanes in some samples. The isotopic (13C, 2H) characteristics of these compounds are being compared to a suite of oils, greases, and drilling fluids used during sample collection to distinguish in situ abiotic and biotic signatures from contaminant compounds. Other initial results have shown the efficacy of various sample-handling procedures designed to reduce surface contamination. This study will contribute to the overall understanding of the role serpentinization plays in the global carbon cycle and its implications for pre-biotic chemistry.

Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases

PubMed Central

Callahan, Michael P.; Smith, Karen E.; Cleaves, H. James; Ruzicka, Josef; Stern, Jennifer C.; Glavin, Daniel P.; House, Christopher H.; Dworkin, Jason P.

2011-01-01

All terrestrial organisms depend on nucleic acids (RNA and DNA), which use pyrimidine and purine nucleobases to encode genetic information. Carbon-rich meteorites may have been important sources of organic compounds required for the emergence of life on the early Earth; however, the origin and formation of nucleobases in meteorites has been debated for over 50 y. So far, the few nucleobases reported in meteorites are biologically common and lacked the structural diversity typical of other indigenous meteoritic organics. Here, we investigated the abundance and distribution of nucleobases and nucleobase analogs in formic acid extracts of 12 different meteorites by liquid chromatography–mass spectrometry. The Murchison and Lonewolf Nunataks 94102 meteorites contained a diverse suite of nucleobases, which included three unusual and terrestrially rare nucleobase analogs: purine, 2,6-diaminopurine, and 6,8-diaminopurine. In a parallel experiment, we found an identical suite of nucleobases and nucleobase analogs generated in reactions of ammonium cyanide. Additionally, these nucleobase analogs were not detected above our parts-per-billion detection limits in any of the procedural blanks, control samples, a terrestrial soil sample, and an Antarctic ice sample. Our results demonstrate that the purines detected in meteorites are consistent with products of ammonium cyanide chemistry, which provides a plausible mechanism for their synthesis in the asteroid parent bodies, and strongly supports an extraterrestrial origin. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules. PMID:21836052

Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases.

PubMed

Callahan, Michael P; Smith, Karen E; Cleaves, H James; Ruzicka, Josef; Stern, Jennifer C; Glavin, Daniel P; House, Christopher H; Dworkin, Jason P

2011-08-23

All terrestrial organisms depend on nucleic acids (RNA and DNA), which use pyrimidine and purine nucleobases to encode genetic information. Carbon-rich meteorites may have been important sources of organic compounds required for the emergence of life on the early Earth; however, the origin and formation of nucleobases in meteorites has been debated for over 50 y. So far, the few nucleobases reported in meteorites are biologically common and lacked the structural diversity typical of other indigenous meteoritic organics. Here, we investigated the abundance and distribution of nucleobases and nucleobase analogs in formic acid extracts of 12 different meteorites by liquid chromatography-mass spectrometry. The Murchison and Lonewolf Nunataks 94102 meteorites contained a diverse suite of nucleobases, which included three unusual and terrestrially rare nucleobase analogs: purine, 2,6-diaminopurine, and 6,8-diaminopurine. In a parallel experiment, we found an identical suite of nucleobases and nucleobase analogs generated in reactions of ammonium cyanide. Additionally, these nucleobase analogs were not detected above our parts-per-billion detection limits in any of the procedural blanks, control samples, a terrestrial soil sample, and an Antarctic ice sample. Our results demonstrate that the purines detected in meteorites are consistent with products of ammonium cyanide chemistry, which provides a plausible mechanism for their synthesis in the asteroid parent bodies, and strongly supports an extraterrestrial origin. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules.

Question 6: coevolution theory of the genetic code: a proven theory.

PubMed

Wong, Jeffrey Tze-Fei

2007-10-01

The coevolution theory proposes that primordial proteins consisted only of those amino acids readily obtainable from the prebiotic environment, representing about half the twenty encoded amino acids of today, and the missing amino acids entered the system as the code expanded along with pathways of amino acid biosynthesis. The isolation of genetic code mutants, and the antiquity of pretran synthesis revealed by the comparative genomics of tRNAs and aminoacyl-tRNA synthetases, have combined to provide a rigorous proof of the four fundamental tenets of the theory, thus solving the riddle of the structure of the universal genetic code.

Oligomerization of mononucleotides on montmorillonite: A potential approach to the prebiotic synthesis of RNA. [Abstract only

NASA Technical Reports Server (NTRS)

Ferris, James P.; Ertem, Goezen; Ding, Zi Ping; Prabahar, Joseph

1994-01-01

The condensation of the 5'-phosphorimidazolide of adenosine (ImpA) on montmorillonite in a pH 8 aqueous solution yields oligomers containing up to 10 monomer units. The regiospecificity of 3',5'-phosphodiester bond formation is enhanced by addition of 10% diadenosine pyrophosphate (AppA) to the reaction mixture. A series of activated derivatives of 5'-AMP was prepared to investigate the effect of the leaving group on oligomer formation. The benzimidazole and p-dimethylamino-pyridine derivatives gave the best yields of oligomers. Factors important for oligomer formation is discussed.

Boron Enrichment in Martian Clay

PubMed Central

Nagashima, Kazuhide; Freeland, Stephen J.

2013-01-01

We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

Evaluation of Glyceraldehyde Under Simulated Prebiotic Conditions

NASA Astrophysics Data System (ADS)

Aguilar-Ovando, E.; Buhse, T.; Negrón-Mendoza, A.

2017-07-01

The aim of this work is to compare the behavior under irradiation of solid and aqueous DL-glyceraldehyde simulating prebiotic conditions. The results show the formation of sugar-like products of prebiotic significance as function of irradiation dose.

Toward a Personalized Approach in Prebiotics Research.

PubMed

Dey, Moul

2017-01-26

Recent characterization of the human microbiome and its influences on health have led to dramatic conceptual shifts in dietary bioactives research. Prebiotic foods that include many dietary fibers and resistant starches are perceived as beneficial for maintaining a healthy gut microbiota. This article brings forward some current perspectives in prebiotic research to discuss why reporting of individual variations in response to interventions will be important to discern suitability of prebiotics as a disease prevention tool.

Prebiotic Oligosaccharides: Special Focus on Fructooligosaccharides, Its Biosynthesis and Bioactivity.

PubMed

Singh, Sudhir P; Jadaun, Jyoti Singh; Narnoliya, Lokesh K; Pandey, Ashok

2017-10-01

The bacterial groups in the gut ecosystem play key role in the maintenance of host's metabolic and structural functionality. The gut microbiota enhances digestion processing, helps in digestion of complex substances, synthesizes beneficial bioactive compounds, enhances bioavailability of minerals, impedes growth of pathogenic microbes, and prevents various diseases. It is, therefore, desirable to have an adequate intake of prebiotic biomolecules, which promote favorable modulation of intestinal microflora. Prebiotics are non-digestible and chemically stable structures that significantly enhance growth and functionality of gut microflora. The non-digestible carbohydrate, mainly oligosaccharides, covers a major part of total available prebiotics as dietary additives. The review describes the types of prebiotic low molecular weight carbohydrates, i.e., oligosaccharides, their structure, biosynthesis, functionality, and applications, with a special focus given to fructooligosaccharides (FOSs). The review provides an update on enzymes executing hydrolytic and fructosyltransferase activities producing prebiotic FOS biomolecules, and future perspectives.

Terrestrial production vs. extraterrestrial delivery of prebiotic organics to the early Earth

NASA Technical Reports Server (NTRS)

Chyba, C. F.; Sagan, C.; Thomas, P. J.; Brookshaw, L.

1991-01-01

A comprehensive treatment of comet/asteroid interaction with the atmosphere, ensuring surface impact, and resulting organic pyrolysis is required to determine whether more than a negligible fraction of the organics in incident comets and asteroids actually survived collision with Earth. Results of such an investigation, using a smoothed particle hydrodynamic simulation of cometary and asteroidal impacts into both oceans and rock, demonstrate that organics will not survive impacts at velocities approx. greater than 10 km s(exp -1), and that even comets and asteroids as small as 100m in radius cannot be aerobraked to below this velocity in 1 bar atmospheres. However, for plausible dense (10 bar CO2) early atmospheres, there will be sufficient aerobraking during atmospheric passage for some organics to survive the ensuing impact. Combining these results with analytical fits to the lunar impact record shows that 4.5 Gyr ago Earth was accreting at least approx. 10(exp 6) kg yr(exp 1) of intact cometary organics, a flux which thereafter declined with a approx. 100 Myr half-life. The extent to which this influx was augmented by asteroid impacts, as well as the effect of more careful modelling of a variety of conservative approximations, is currently being quantified. These results may be placed in context by comparison with in situ organic production from a variety of terrestrial energy sources, as well as organic delivery by interplanetary dust. Which source dominated the early terrestrial prebiotic inventory is found to depend on the nature of the early terrestrial atmosphere. However, there is an intriguing symmetry: it is exactly those dense CO2 atmospheres where in situ atmospheric production of organic molecules should be the most difficult, in which intact cometary organics would be delivered in large amounts.

Three stages in the evolution of the genetic code

NASA Technical Reports Server (NTRS)

Baumann, U.; Oro, J.

1993-01-01

A diversification of the genetic code based on the number of codons available for the proteinous amino acids is established. Three groups of amino acids during evolution of the code are distinguished. On the basis of their chemical complexity those amino acids emerging later in a translation process are derived. Codon number and chemical complexity indicate that His, Phe, Tyr, Cys and either Lys or Asn were introduced in the second stage, whereas the number of codons alone gives evidence that Trp and Met were introduced in the third stage. The amino acids of stage 1 use purine-rich codons, while all the amino acids introduced in the second stage, in contrast, use pyrimidines in the third position of their codons. A low abundance of pyrimidines during early translation is derived. This assumption is supported by experiments on non-enzymatic replication and interactions of hairpin loops with a complementary strand. A back extrapolation concludes a high purine content of the first nucleic acids, which gradually decreased during their evolution. Amino acids independently available from prebiotic synthesis were thus correlated to purine-rich codons. Implications on the prebiotic replication are discussed also in the light of recent codon usage data.

Optimization of simultaneously enzymatic fructo- and inulo-oligosaccharide production using co-substrates of sucrose and inulin from Jerusalem artichoke.

PubMed

Kawee-Ai, Arthitaya; Ritthibut, Nuntinee; Manassa, Apisit; Moukamnerd, Churairat; Laokuldilok, Thunnop; Surawang, Suthat; Wangtueai, Sutee; Phimolsiripol, Yuthana; Regenstein, Joe M; Seesuriyachan, Phisit

2018-02-07

Prebiotic substances are extracted from various plant materials or enzymatic hydrolysis of different substrates. The production of fructo-oligosaccharide (FOS) and inulo-oligosaccharide (IOS) was performed by applying two substrates, sucrose and inulin; oligosaccharide yields were maximized using central composite design to evaluate the parameters influencing oligosaccharide production. Inulin from Jerusalem artichoke (5-15% w/v), sucrose (50-70% w/v), and inulinase from Aspergillus niger (2-7 U/g) were used as variable parameters for optimization. Based on our results, the application of sucrose and inulin as co-substrates for oligosaccharide production through inulinase hydrolysis and synthesis is viable in comparative to a method using a single substrate. Maximum yields (674.82 mg/g substrate) were obtained with 5.95% of inulin, 59.87% of sucrose, and 5.68 U/g of inulinase, with an incubation period of 9 hr. The use of sucrose and inulin as co-substrates in the reaction simultaneously produced FOS and IOS from sucrose and inulin. Total conversion yield was approximately 67%. Our results support the high value-added production of oligosaccharides using Jerusalem artichoke, which is generally used as a substrate in prebiotics and/or bioethanol production.

Hypolipidemic Effect of Red Gram (Cajanus cajan L.) Prebiotic Oligosaccharides in Wistar NIN Rats.

PubMed

Shakappa, Devindra; Talari, Aruna; Rajkumar, Hemalatha; Shujauddin, Mohammed

2017-08-24

The hypolipidemic effect of red gram prebiotics of raffinose family oligosaccharides was studied in Wistar National Institute of Nutrition male rat strain. The study consisted of 36 rats randomly divided into three groups of 12 rats each. For 16 weeks, Group I was fed with the control diet; Group II was fed with a diet containing 3% standard raffinose as the reference group; Group III received the diet containing 3% red gram prebiotics. The results showed that the gain in body weight was low in the red gram prebiotics-supplemented group followed by the control group; highest increase of body weight was seen in the raffinose standard-fed group. Serum glucose levels of the red gram prebiotic-fed group decreased 14.92% compared to the control group and increased 2.07% compared to the reference group. The decrease in serum triglycerides (TG) levels of the red gram prebiotic-fed groups was 32.76% compared to the control group and 33.64% compared to the reference group. Decrease in the serum TC of the red gram-fed animals was 18.51% and 4.63% compared to the control group and the reference group, respectively. Increase in the level of serum high-density lipoprotein cholesterol (HDL-C) in the red gram-fed animals was 18.51% compared to the control group and 4.63% compared to the reference group. The present study can be a proof for the use of prebiotics as a preventive measure for overweight and obesity in humans, and legume prebiotics can be explored as a novel prebiotic product in the consumer market.

The origin and early evolution of life on Earth.

PubMed

Oró, J; Miller, S L; Lazcano, A

1990-01-01

We do not have a detailed knowledge of the processes that led to the appearance of life on Earth. In this review we bring together some of the most important results that have provided insights into the cosmic and primitive Earth environments, particularly those environments in which life is thought to have originated. To do so, we first discuss the evidence bearing on the antiquity of life on our planet and the prebiotic significance of organic compounds found in interstellar clouds and in primitive solar system bodies such as comets, dark asteroids, and carbonaceous chondrites. This is followed by a discussion on the environmental models of the Hadean and early Archean Earth, as well as on the prebiotic formation of organic monomers and polymers essential to life. We then consider the processes that may have led to the appearance in the Archean of the first cells, and how these processes may have affected the early steps of biological evolution. Finally, the significance of these results to the study of the distribution of life in the Universe is discussed.

Prebiotic-Like Condensations of Cyanamide and Glyoxal: Revisiting Intractable Biotars.

PubMed

Lavado, Nieves; Escamilla, Juan Carlos; Ávalos, Martín; Babiano, Reyes; Cintas, Pedro; Jiménez, José Luis; Palacios, Juan Carlos

2016-09-12

We report a detailed investigation into the nature of products that are generated by the reactions of cyanamide and glyoxal, two small molecules of astrochemical and prebiotic significance, under different experimental conditions. The experimental data suggest that the formation of oligomeric structures is related in part to the formation of insoluble tholins in the presence of oxygen-containing molecules. Although oligomerization proceeds well in water, product isolation turned out to be impractical. Instead, solid precipitates were obtained easily in acetone. Crude mixtures have been thoroughly scrutinized by spectroscopic methods, in particular NMR and mass spectroscopy (ESI mode), which are all consistent with the generation of a few functional groups that are embedded into regular chains of five- and six-membered rings, thereby pointing to a supramolecular organization. Three different models of cross-condensation and chain growth are suggested. These synthetic explorations provide further insights into the formation of complex organic matter in interstellar scenarios and extraterrestrial bodies that might have played a pivotal role in chemical evolution. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Clay energetics in chemical evolution

NASA Technical Reports Server (NTRS)

Coyne, L. M.

1986-01-01

Clays have been implicated in the origin of terrestrial life since the 1950's. Originally they were considered agents which aid in selecting, concentrating and promoting oligomerization of the organic monomeric substituents of cellular life forms. However, more recently, it has been suggested that minerals, with particular emphasis on clays, may have played a yet more fundamental role. It has been suggested that clays are prototypic life forms in themselves and that they served as a template which directed the self-assembly of cellular life. If the clay-life theory is to have other than conceptual credibility, clays must be shown by experiment to execute the operations of cellular life, not only individually, but also in a sufficiently concerted manner as to produce some semblance of the functional attributes of living cells. Current studies are focussed on the ability of clays to absorb, store and transfer energy under plausible prebiotic conditions and to use this energy to drive chemistry of prebiotic relevance. Conclusions of the work are applicable to the role of clays either as substrates for organic chemistry, or in fueling their own life-mimetic processes.

Prebiotic organic microstructures.

PubMed

Bassez, Marie-Paule; Takano, Yoshinori; Kobayashi, Kensei

2012-08-01

Micro- and sub-micrometer spheres, tubules and fiber-filament soft structures have been synthesized in our experiments conducted with 3 MeV proton irradiations of a mixture of simple inorganic constituents, CO, N(2) and H(2)O. We analysed the irradiation products, with scanning electron microscopy (SEM) and atomic force microscopy (AFM). These laboratory organic structures produced a wide variety of proteinaceous and non-proteinaceous amino acids after HCl hydrolysis. The enantiomer analysis for D,L-alanine confirmed that the amino acids were abiotically synthesized during the laboratory experiment. We discuss the presence of CO(2) and the production of H(2) during exothermic processes of serpentinization and consequently we discuss the production of hydrothermal CO in a ferromagnesian silicate mineral environment. We also discuss the low intensity of the Earth's magnetic field during the Paleoarchaean Era and consequently we conclude that excitation sources arising from cosmic radiation were much more abundant during this Era. We then show that our laboratory prebiotic microstructures might be synthesized during the Archaean Eon, as a product of the serpentinization process of the rocks and of their mineral contents.

H2-rich fluids from serpentinization: Geochemical and biotic implications

PubMed Central

Sleep, N. H.; Meibom, A.; Fridriksson, Th.; Coleman, R. G.; Bird, D. K.

2004-01-01

Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impact. This process formed some of the ferric iron in the Earth's mantle. For the rest of Earth's history, serpentinites covered only a small fraction of the Earth's surface but were an important prebiotic and biotic environment. Extant methanogens react H2 with CO2 to form methane. This is a likely habitable environment on large silicate planets. The catalytic properties of FeNi3 allow complex organic compounds to form within serpentinite and, when mixed with atmospherically produced complex organic matter and waters that circulated through basalts, constitutes an attractive prebiotic substrate. Conversely, inorganic catalysis of methane by FeNi3 competes with nascent and extant life. PMID:15326313

Molecular characterization and heterologous expression of a Xanthophyllomyces dendrorhous α-glucosidase with potential for prebiotics production.

PubMed

Gutiérrez-Alonso, Patricia; Gimeno-Pérez, María; Ramírez-Escudero, Mercedes; Plou, Francisco J; Sanz-Aparicio, Julia; Fernández-Lobato, María

2016-04-01

Basidiomycetous yeast Xanthophyllomyces dendrorhous expresses an α-glucosidase with strong transglycosylation activity producing prebiotic sugars such as panose and an unusual tetrasaccharides mixture including α-(1-6) bonds as major products, which makes it of biotechnological interest. Initial analysis pointed to a homodimeric protein of 60 kDa subunit as responsible for this activity. In this study, the gene Xd-AlphaGlu was characterized. The 4131-bp-long gene is interrupted by 13 short introns and encodes a protein of 990 amino acids (Xd-AlphaGlu). The N-terminal sequence of the previously detected 60 kDa protein resides in this larger protein at residues 583-602. Functionality of the gene was proved in Saccharomyces cerevisiae, which produced a protein of about 130 kDa containing Xd-AlphaGlu sequences. All properties of the heterologously expressed protein, including thermal and pH profiles, activity on different substrates, and ability to produce prebiotic sugars were similar to that of the α-glucosidase produced in X. dendrorhous. No activity was detected in S. cerevisiae containing exclusively the 1256-bp from gene Xd-AlphaGlu that would encode synthesis of the 60 kDa protein previously detected. Data were compatible with an active monomeric α-glucosidase of 990 amino acids and an inactive hydrolysis product of 60 kDa. Protein Xd-AlphaGlu contained most of the elements characteristic of α-glucosidases included in the glycoside hydrolases family GH31 and its structural model based on the homologous human maltase-glucoamylase was obtained. Remarkably, the Xd-AlphaGlu C-terminal domain presents an unusually long 115-residue insertion that could be involved in this enzyme's activity against long-size substrates such as maltoheptaose and soluble starch.

Effects of a galacto-oligosaccharide-rich diet on fecal microbiota and metabolite profiles in mice.

PubMed

Cheng, W; Lu, J; Lin, W; Wei, X; Li, H; Zhao, X; Jiang, A; Yuan, J

2018-03-01

Galacto-oligosaccharides (GOS) are prebiotics that positively affect the host's gut microbiota, which is important for the health of the host. Most previous studies focused on specific flora components (e.g. Bifidobacterium and Lactobacillus); very few have investigated the relationship between flora and metabolites. Here, we used 16S rRNA analysis and metabolomics to analyze the effect of GOS on microbiota and metabolites. Results show that the abundance of Ruminococcaceae and Oscillibacter decreased significantly in GOS-fed mice. Twenty-one metabolites, including oleic acid, arachidic acid, and behenic acid, decreased significantly in the GOS-fed mice. Fatty acid synthesis and blood triglyceride content significantly decreased in the GOS-fed mice compared with those in the control mice, suggesting that GOS may improve lipid metabolism in mice. Additionally, after three weeks of a GOS-rich diet, the mouse microbiota was significantly enriched in Alloprevotella, Bacteroides, and Parasutterella. The blood glucose level of the GOS-fed group was significantly higher than that of the control group, whereas the abundance of Coprococcus and Odoribacter (butyrate-producing bacteria) was significantly decreased. The metabolism of butyrate, known to reduce plasma glucose levels, was significantly downregulated in the GOS-fed mice, an effect potentially detrimental to the glucose metabolism of the host. This dual-omics analysis provided important information on the changes in host-microbe-metabolite interactions resulting from GOS supplementation. Our results provide evidence that GOS may improve lipid metabolism, and that long-term GOS supplementation had a detrimental effect on the host's glucose metabolism, which could be important for optimizing methods of prebiotic supplementation and developing approaches to prevent diseases using prebiotic interventions.

Targeting the gut microbiota with inulin-type fructans: preclinical demonstration of a novel approach in the management of endothelial dysfunction.

PubMed

Catry, Emilie; Bindels, Laure B; Tailleux, Anne; Lestavel, Sophie; Neyrinck, Audrey M; Goossens, Jean-François; Lobysheva, Irina; Plovier, Hubert; Essaghir, Ahmed; Demoulin, Jean-Baptiste; Bouzin, Caroline; Pachikian, Barbara D; Cani, Patrice D; Staels, Bart; Dessy, Chantal; Delzenne, Nathalie M

2018-02-01

To investigate the beneficial role of prebiotics on endothelial dysfunction, an early key marker of cardiovascular diseases, in an original mouse model linking steatosis and endothelial dysfunction. We examined the contribution of the gut microbiota to vascular dysfunction observed in apolipoprotein E knockout (Apoe -/- ) mice fed an n-3 polyunsaturated fatty acid (PUFA)-depleted diet for 12 weeks with or without inulin-type fructans (ITFs) supplementation for the last 15 days. Mesenteric and carotid arteries were isolated to evaluate endothelium-dependent relaxation ex vivo. Caecal microbiota composition (Illumina Sequencing of the 16S rRNA gene) and key pathways/mediators involved in the control of vascular function, including bile acid (BA) profiling, gut and liver key gene expression, nitric oxide and gut hormones production were also assessed. ITF supplementation totally reverses endothelial dysfunction in mesenteric and carotid arteries of n-3 PUFA-depleted Apoe -/- mice via activation of the nitric oxide (NO) synthase/NO pathway. Gut microbiota changes induced by prebiotic treatment consist in increased NO-producing bacteria, replenishment of abundance in Akkermansia and decreased abundance in bacterial taxa involved in secondary BA synthesis. Changes in gut and liver gene expression also occur upon ITFs suggesting increased glucagon-like peptide 1 production and BA turnover as drivers of endothelium function preservation. We demonstrate for the first time that ITF improve endothelial dysfunction, implicating a short-term adaptation of both gut microbiota and key gut peptides. If confirmed in humans, prebiotics could be proposed as a novel approach in the prevention of metabolic disorders-related cardiovascular diseases. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Prebiotics from Marine Macroalgae for Human and Animal Health Applications

PubMed Central

O’Sullivan, Laurie; Murphy, Brian; McLoughlin, Peter; Duggan, Patrick; Lawlor, Peadar G.; Hughes, Helen; Gardiner, Gillian E.

2010-01-01

The marine environment is an untapped source of bioactive compounds. Specifically, marine macroalgae (seaweeds) are rich in polysaccharides that could potentially be exploited as prebiotic functional ingredients for both human and animal health applications. Prebiotics are non-digestible, selectively fermented compounds that stimulate the growth and/or activity of beneficial gut microbiota which, in turn, confer health benefits on the host. This review will introduce the concept and potential applications of prebiotics, followed by an outline of the chemistry of seaweed polysaccharides. Their potential for use as prebiotics for both humans and animals will be highlighted by reviewing data from both in vitro and in vivo studies conducted to date. PMID:20714423

Toward a Personalized Approach in Prebiotics Research

PubMed Central

Dey, Moul

2017-01-01

Recent characterization of the human microbiome and its influences on health have led to dramatic conceptual shifts in dietary bioactives research. Prebiotic foods that include many dietary fibers and resistant starches are perceived as beneficial for maintaining a healthy gut microbiota. This article brings forward some current perspectives in prebiotic research to discuss why reporting of individual variations in response to interventions will be important to discern suitability of prebiotics as a disease prevention tool. PMID:28134778

Oligosaccharides in infant formula: more evidence to validate the role of prebiotics.

PubMed

Vandenplas, Yvan; Zakharova, Irina; Dmitrieva, Yulia

2015-05-14

The gastrointestinal (GI) microbiota differs between breast-fed and classic infant formula-fed infants. Breast milk is rich in prebiotic oligosaccharides (OS) and may also contain some probiotics, but scientific societies do not recommend the addition of prebiotic OS or probiotics to standard infant formula. Nevertheless, many infant formula companies often add one or the other or both. Different types of prebiotic OS are used in infant formula, including galacto-oligosaccharide, fructo-oligosaccharide, polydextrose and mixtures of these OS, but none adds human milk OS. There is evidence that the addition of prebiotics to infant formula brings the GI microbiota of formula-fed infants closer to that of breast-fed infants. Prebiotics change gut metabolic activity (by decreasing stool pH and increasing SCFA), have a bifidogenic effect and bring stool consistency and defecation frequency closer to those of breast-fed infants. Although there is only limited evidence that these changes in GI microbiota induce a significant clinical benefit for the immune system, interesting positive trends have been observed in some markers. Additionally, adverse effects are extremely seldom. Prebiotics are added to infant formula because breast milk contains human milk OS. Because most studies suggest a trend of beneficial effects and because these ingredients are very safe, prebiotics bring infant formula one step closer to the golden standard of breast milk.

Early low volume oral synbiotic/prebiotic supplemented enteral stimulation of the gut in patients with severe acute pancreatitis: a prospective feasibility study.

PubMed

Plaudis, H; Pupelis, G; Zeiza, K; Boka, V

2012-01-01

Experience with administration of synbiotics (prebiotics/probiotics) in patients with severe acute pancreatitis (SAP) has demonstrated immunomodulatory capacity. The aim of this trial was evaluation of the feasibility and perspective of early clinical application of oral synbiotic/prebiotic supplements in patients with SAP. 90 SAP patients were enrolled during the period from 2005-2008. Patients were stratified according to the feeding mode. CONTROL (n = 32) group received standard whole protein feeding formula. SYNBIO (n = 30) and FIBRE groups (n = 28) received early (within first 24-48 hours) synbiotic or prebiotic supplements. Oral administration of synbiotics or prebiotics was commenced when patients were able to sip water. Daily provided average volume and calories of synbiotic/prebiotic blends were smaller compared to the CONTROL, p = 0.001. Oral administration of synbiotic/prebiotic supplements was associated with lower infection rate (pancreatic and peripancreatic necrosis) compared to the CONTROL, (p = 0.03; p = 0.001), lower rate of surgical interventions, p = 0.005, shorter ICU (p = 0.05) and hospital stay (p = 0.03). Synbiotic supplemented enteral stimulation of the gut resulted in reduced mortality rate compared to the CONTROL, p = 0.02. Early low volume oral synbiotic/prebiotic supplemented enteral stimulation of the gut seems to be a potentially valuable complement to the routine treatment protocol of SAP.

Fiber, prebiotics, and diarrhea: what, why, when and how.

PubMed

Generoso, Simone de Vasconcelos; Lages, Priscilla Ceci; Correia, Maria Isabel Toulsson Davisson

2016-07-15

Dietary fiber and prebiotics have been the focus of research and discussion for decades, but there are still pending concepts and definitions, in particular when addressing their use in the prevention and treatment of diarrhea. The purpose of this review is to present the latest advances in the understanding of dietary fiber and prebiotics, to review their proven role in the management of diarrhea, and to postulate the best timings and optimal doses. The use of prebiotics has encompassed not only prevention but also the treatment of distinct types of diarrhea, at different treatment moments, and with regard to various different markers of outcome. Furthermore, the description of soluble fibers claiming to be prebiotics, and vice versa, has too often been the tone in the literature, which has led to misconceptions in classification and, consequently, confusion over the interpretation of results. It remains difficult to establish a consensus about the real impact of fiber and prebiotics on the prevention and therapy of diarrhea. The review highlights the overlapping concepts of fiber and prebiotics, and supports the need for adequate individualization of their use, according to the goal - either prevention or treatment of diarrhea - as well as the optimal timing and dose to be used. Nonetheless, viscous soluble fibers seem to be the best option in treating diarrhea, whereas prebiotics are more important in preventing and avoiding recurrence.

Organic matter in carbonaceous chondrites, planetary satellites, asteroids and comets

NASA Technical Reports Server (NTRS)

Cronin, John R.; Pizzarello, Sandra; Cruikshank, Dale P.

1988-01-01

A detailed review is given of the organic compounds found in carbonaceous chondrite meteorites, especially the Murchison meteorite, and detected spectroscopically in other solar-system objects. The chemical processes by which the organic compounds could have formed in the early solar system and the conditions required for these processes are discussed, taking into account the possible alteration of the compounds during the lifetime of the meteoroid. Also considered are the implications for prebiotic evolution and the origin of life. Diagrams, graphs, and tables of numerical data are provided.

Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth. Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers

NASA Astrophysics Data System (ADS)

Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

2016-06-01

In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity.

Probiotics and prebiotics associated with aquaculture: A review.

PubMed

Akhter, Najeeb; Wu, Bin; Memon, Aamir Mahmood; Mohsin, Muhammad

2015-08-01

There is a rapidly growing literature, indicating success of probiotics and prebiotics in immunomodulation, namely the stimulation of innate, cellular and humoral immune response. Probiotics are considered to be living microorganisms administered orally and lead to health benefits. These Probiotics are microorganisms in sufficient amount to alter the microflora (by implantation or colonization) in specific host's compartment exerting beneficial health effects at this host. Nevertheless, Prebiotics are indigestible fiber which enhances beneficial commensally gut bacteria resulting in improved health of the host. The beneficial effects of prebiotics are due to by-products derived from the fermentation of intestinal commensal bacteria. Among the many health benefits attributed to probiotics and prebiotics, the modulation of the immune system is one of the most anticipated benefits and their ability to stimulate systemic and local immunity, deserves attention. They directly enhance the innate immune response, including the activation of phagocytosis, activation of neutrophils, activation of the alternative complement system, an increase in lysozyme activity, and so on. Prebiotics acting as immunosaccharides directly impact on the innate immune system of fish and shellfish. Therefore, both probiotics and prebiotics influence the immunomodulatory activity boosting up the health benefits in aquatic animals. Copyright © 2015 Elsevier Ltd. All rights reserved.

The formation of prebiotic molecules in star-forming regions

NASA Astrophysics Data System (ADS)

Rivilla, V. M.

New sensitive observations using the current generation of (sub)millimeter telescopes have revealed in several star-forming regions molecular species of different chemical families (e.g. sugars, esters, isocyanates, phosphorus-bearing species) that may play an important role in prebiotic chemistry, and eventually in the origin of life. The observed molecular abundances of complex organic molecules (glycolaldehyde, ethylene glycol and ethyl formate) are better explained by surface-phase chemistry on dust grains, although gas-phase reactions can also play an important role, as in the case of methyl isocyanate. The PO molecule - a basic chemical bond to build-up the backbone of the DNA - has been detected for the first time in star-forming regions. These new observations indicate that phosphorus, a key element for the development of life, is much more abundant in star-forming regions than previously thought.

An organismic critique of molecular darwinism.

PubMed

Wicken, J S

1985-12-21

The molecular darwinian approach to the emergence of life treats the competition between RNA sequences for nucleotide resources as the primordial selective process in prebiotic evolution, which prescribes possible pathways for the subsequent elaboration of organizational relationships. Since success in this competition is determined by the "phenotypic" properties of RNA strands in the absence of organizational context, the genesis of biotic organization is dependent upon the establishment of co-operative, hypercyclic interactions between competing RNA sequences. The thesis of this paper is that hypercycle theory is based on unwarranted assumptions about the conditions of prebiotic evolution, and that the implications of these assumptions run counter to both empirical evidence and to the rational by which natural selection operates in evolution generally. An organismic alternative to hypercycle theory is suggested, based on the catalytic microsphere and the thermodynamics of selection.

Potentially Prebiotic Syntheses of Condensed Phosphates

NASA Technical Reports Server (NTRS)

Keefe, Anthony D.; Miller, Stanley L.

1996-01-01

In view of the importance of a prebiotic source of high energy phosphates, we have investigated a number of potentially prebiotic processes to produce condensed phosphates from orthophosphate and cyclic trimetaphosphate from tripolyphosphate. The reagents investigated include polymerizing nitriles, acid anhydrides, lactones, hexamethylene tetramine and carbon suboxide. A number of these processes give substantial yields of pyrophosphate from orthophosphate and trimetaphosphate from tripolyphosphate. Although these reactions may have been applicable in local areas, they are not sufficiently robust to have been of importance in the prebiotic open ocean.

Nucleic acids, proteins, and chirality

NASA Technical Reports Server (NTRS)

Usher, D. A.; Profy, A. T.; Walstrum, S. A.; Needels, M. C.; Bulack, S. C.; Lo, K. M.

1984-01-01

The present investigation is concerned with experimental results related, in one case, to the chirality of nucleotides, and, in another case, to the possibility of a link between the chirality of nucleic acids, and that of peptides. It has been found that aminoacylation of the 'internal' hydroxyl group of a dinucleoside monophosphate can occur stereoselectively. However, this reaction has not yet been made a part of a working peptide synthesis scheme. The formation and cleavage of oligonucleotides is considered. In the event of the formation of a helical complex between the oligonucleotide and the polymer, 1-prime,5-prime-bonds in the oligomer are found to become more resistant towards cleavage. The conditions required for peptide bond formation are examined, taking into account the known structures of RNA and possible mechanisms for prebiotic peptide bond formation. The possibility is considered that the 2-prime,5-prime-internucleotide linkage could have played an important part in the early days of biological peptide synthesis.

The prebiotic concept and human health: a changing landscape with riboflavin as a novel prebiotic candidate?

PubMed

Steinert, R E; Sadaghian Sadabad, M; Harmsen, H J M; Weber, P

2016-12-01

Emerging evidence suggests that the gut microbiota has a critical role in both the maintenance of human health and the pathogenesis of many diseases. Modifying the colonic microbiota using functional foods has attracted significant research effort and product development. The pioneering concept of prebiotics, as introduced by Gibson and Roberfroid in the 1990s, emphasized the importance of diet in the modulation of the gut microbiota and its relationships to human health. Increasing knowledge of the intestinal microbiota now suggests a more comprehensive definition. This paper briefly reviews the basics of the prebiotic concept with a discussion of recent attempts to refine the concept to open the door for novel prebiotic food ingredients, such as polyphenols, minerals and vitamins.

Probiotics and prebiotics in the elderly

PubMed Central

Hamilton-Miller, J

2004-01-01

Probiotics (usually lactobacilli and bifidobacteria) and prebiotics (non-digestible oligosaccharides) have been shown to be useful in preventing certain disease conditions as well as possibly promoting specific aspects of health. In the present review, the evidence from clinical trials for benefits from probiotics and prebiotics to elderly populations is presented and discussed, specifically in respect of three common conditions found in the elderly. Both probiotics and prebiotics may be helpful in malnutrition, particularly in lactose intolerance and calcium absorption, and in constipation. Probiotics have been shown clearly to boost immunity in the elderly, but the clinical significance of this remains to be clarified. These results are encouraging, and further large scale studies seem justified to establish the place of probiotic and prebiotic supplements in elderly subjects. PMID:15299153

Strategies for Detecting Biological Molecules on Titan.

PubMed

Neish, Catherine D; Lorenz, Ralph D; Turtle, Elizabeth P; Barnes, Jason W; Trainer, Melissa G; Stiles, Bryan; Kirk, Randolph; Hibbitts, Charles A; Malaska, Michael J

2018-05-02

Saturn's moon Titan has all the ingredients needed to produce "life as we know it." When exposed to liquid water, organic molecules analogous to those found on Titan produce a range of biomolecules such as amino acids. Titan thus provides a natural laboratory for studying the products of prebiotic chemistry. In this work, we examine the ideal locales to search for evidence of, or progression toward, life on Titan. We determine that the best sites to identify biological molecules are deposits of impact melt on the floors of large, fresh impact craters, specifically Sinlap, Selk, and Menrva craters. We find that it is not possible to identify biomolecules on Titan through remote sensing, but rather through in situ measurements capable of identifying a wide range of biological molecules. Given the nonuniformity of impact melt exposures on the floor of a weathered impact crater, the ideal lander would be capable of precision targeting. This would allow it to identify the locations of fresh impact melt deposits, and/or sites where the melt deposits have been exposed through erosion or mass wasting. Determining the extent of prebiotic chemistry within these melt deposits would help us to understand how life could originate on a world very different from Earth. Key Words: Titan-Prebiotic chemistry-Solar system exploration-Impact processes-Volcanism. Astrobiology xx, xxx-xxx.

Polydextrose enrichment of infant formula demonstrates prebiotic characteristics by altering intestinal microbiota, organic acid concentrations, and cytokine expression in suckling piglets.

PubMed

Herfel, Tina M; Jacobi, Sheila K; Lin, Xi; Fellner, Vivek; Walker, D Carey; Jouni, Zeina E; Odle, Jack

2011-12-01

Oligosaccharides, the 3rd-most abundant component in human milk, are virtually absent from infant formulas and from the cow milk on which most are based. In breast-fed infants, human milk oligosaccharides (HMO) act as both receptor analogs, interfering with pathogen adhesion, and as prebiotics, stimulating the growth of certain commensal bacteria (e.g. bifidobacteria) and supporting the innate immunity. To further align the functional properties of infant formula with those of human milk, polydextrose (PDX) is proposed as a substitute for HMO. To determine the prebiotic functionality of PDX, 1-d-old pigs were fed a cow milk-based formula supplemented with increasing concentrations of PDX (0, 1.7, 4.3, 8.5, or 17 g/L) for 18 d (n = 13). Additional reference groups included pigs sampled at d 0 and sow-reared pigs sampled at d 18 (n = 12). Ileal Lactobacilli CFU, but not Bifidobacteria, increased linearly with increasing PDX (P = 0.02). The propionic acid concentration in digesta linearly increased with the PDX level (P = 0.045) and lactic acid increased linearly by 5-fold with increasing PDX (P = 0.001). Accordingly, digesta pH decreased linearly (P < 0.05) as PDX increased, with a maximal reduction approaching 0.5 pH units in pigs fed 17 g/L. Expression of TNFα, IL-1β, and IL-8 showed a negative quadratic pattern in response to PDX supplementation, declining at intermediate concentrations and rebounding at higher concentrations of PDX. In summary, PDX enrichment of infant formula resulted in a prebiotic effect by increasing ileal lactobacilli and propionic and lactic acid concentrations and decreasing pH with associated alterations in ileal cytokine expression.

Formation of amino acids and nucleotide bases in a Titan atmosphere simulation experiment.

PubMed

Hörst, S M; Yelle, R V; Buch, A; Carrasco, N; Cernogora, G; Dutuit, O; Quirico, E; Sciamma-O'Brien, E; Smith, M A; Somogyi, A; Szopa, C; Thissen, R; Vuitton, V

2012-09-01

The discovery of large (>100 u) molecules in Titan's upper atmosphere has heightened astrobiological interest in this unique satellite. In particular, complex organic aerosols produced in atmospheres containing C, N, O, and H, like that of Titan, could be a source of prebiotic molecules. In this work, aerosols produced in a Titan atmosphere simulation experiment with enhanced CO (N(2)/CH(4)/CO gas mixtures of 96.2%/2.0%/1.8% and 93.2%/5.0%/1.8%) were found to contain 18 molecules with molecular formulae that correspond to biological amino acids and nucleotide bases. Very high-resolution mass spectrometry of isotopically labeled samples confirmed that C(4)H(5)N(3)O, C(4)H(4)N(2)O(2), C(5)H(6)N(2)O(2), C(5)H(5)N(5), and C(6)H(9)N(3)O(2) are produced by chemistry in the simulation chamber. Gas chromatography-mass spectrometry (GC-MS) analyses of the non-isotopic samples confirmed the presence of cytosine (C(4)H(5)N(3)O), uracil (C(5)H(4)N(2)O(2)), thymine (C(5)H(6)N(2)O(2)), guanine (C(5)H(5)N(5)O), glycine (C(2)H(5)NO(2)), and alanine (C(3)H(7)NO(2)). Adenine (C(5)H(5)N(5)) was detected by GC-MS in isotopically labeled samples. The remaining prebiotic molecules were detected in unlabeled samples only and may have been affected by contamination in the chamber. These results demonstrate that prebiotic molecules can be formed by the high-energy chemistry similar to that which occurs in planetary upper atmospheres and therefore identifies a new source of prebiotic material, potentially increasing the range of planets where life could begin.

Prebiotics in infant formula

PubMed Central

Vandenplas, Yvan; Greef, Elisabeth De; Veereman, Gigi

2014-01-01

The gastrointestinal microbiota of breast-fed babies differ from classic standard formula fed infants. While mother's milk is rich in prebiotic oligosaccharides and contains small amounts of probiotics, standard infant formula doesn’t. Different prebiotic oligosaccharides are added to infant formula: galacto-oligosaccharides, fructo-oligosaccharide, polydextrose, and mixtures of these. There is evidence that addition of prebiotics in infant formula alters the gastrointestinal (GI) microbiota resembling that of breastfed infants. They are added to infant formula because of their presence in breast milk. Infants on these supplemented formula have a lower stool pH, a better stool consistency and frequency and a higher concentration of bifidobacteria in their intestine compared to infants on a non-supplemented standard formula. Since most studies suggest a trend for beneficial clinical effects, and since these ingredients are very safe, prebiotics bring infant formula one step closer to breastmilk, the golden standard. However, despite the fact that adverse events are rare, the evidence on prebiotics of a significant health benefit throughout the alteration of the gut microbiota is limited. PMID:25535999

Prebiotics in infant formula.

PubMed

Vandenplas, Yvan; De Greef, Elisabeth; Veereman, Gigi

2014-01-01

The gastrointestinal microbiota of breast-fed babies differ from classic standard formula fed infants. While mother's milk is rich in prebiotic oligosaccharides and contains small amounts of probiotics, standard infant formula doesn't. Different prebiotic oligosaccharides are added to infant formula: galacto-oligosaccharides, fructo-oligosaccharide, polydextrose, and mixtures of these. There is evidence that addition of prebiotics in infant formula alters the gastrointestinal (GI) microbiota resembling that of breastfed infants. They are added to infant formula because of their presence in breast milk. Infants on these supplemented formula have a lower stool pH, a better stool consistency and frequency and a higher concentration of bifidobacteria in their intestine compared to infants on a non-supplemented standard formula. Since most studies suggest a trend for beneficial clinical effects, and since these ingredients are very safe, prebiotics bring infant formula one step closer to breastmilk, the golden standard. However, despite the fact that adverse events are rare, the evidence on prebiotics of a significant health benefit throughout the alteration of the gut microbiota is limited.

Probiotics and prebiotics--perspectives and challenges.

PubMed

Figueroa-González, Ivonne; Quijano, Guillermo; Ramírez, Gerardo; Cruz-Guerrero, Alma

2011-06-01

Owing to their health benefits, probiotics and prebiotics are nowadays widely used in yogurts and fermented milks, which are leader products of functional foods worldwide. The world market for functional foods has grown rapidly in the last three decades, with an estimated size in 2003 of ca US$ 33 billion, while the European market estimation exceeded US$ 2 billion in the same year. However, the production of probiotics and prebiotics at industrial scale faces several challenges, including the search for economical and abundant raw materials for prebiotic production, the low-cost production of probiotics and the improvement of probiotic viability after storage or during the manufacturing process of the functional food. In this review, functional foods based on probiotics and prebiotics are introduced as a key biotechnological field with tremendous potential for innovation. A concise state of the art addressing the fundamentals and challenges for the development of new probiotic- and prebiotic-based foods is presented, the niches for future research being clearly identified and discussed. Copyright © 2011 Society of Chemical Industry.

Valorization of Cheese and Tofu Whey through Enzymatic Synthesis of Lactosucrose.

PubMed

Corzo-Martinez, Marta; Luscher, Alice; de Las Rivas, Blanca; Muñoz, Rosario; Moreno, F Javier

2015-01-01

This work deals with the development of a new bioprocess for the efficient synthesis of lactosucrose, a potential prebiotic oligosaccharide with a high value-added, from two important and inexpensive agro-industrial by-products such as tofu whey and cheese whey permeate. The bioconversion is driven by the ability of the enzyme levansucrase SacB from Bacillus subtilis CECT 39 to transfructosylate lactose contained in the cheese whey permeate by using not only sucrose but also raffinose and stachyose, which are present in considerable amounts in the tofu whey, as suitable donors of fructosyl moieties. The maximum lactosucrose concentration obtained from both by-products was 80.1 g L-1 after a short reaction time 120 min at 37°C, leading to productivity and specific productivity values of 40.1 g lactosucrose L-1 h-1 and 80.1 mg lactosucrose U enzyme-1 h-1, respectively. Findings contained in this work could provide a new strategy to valorize agro-industrial by-products as cheese whey permeate and, specially, tofu whey by means of their use as renewable resources in the enzymatic synthesis of bioactive oligosaccharides.

Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

NASA Technical Reports Server (NTRS)

Weber, A. L.

1985-01-01

The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

Formation Of Amino Acids And Nucleotide Bases In A Titan Atmosphere Simulation Experiment

NASA Astrophysics Data System (ADS)

Horst, Sarah; Yelle, R. V.; Buch, A.; Carrasco, N.; Cernogora, G.; Dutuit, O.; Quirico, E.; Sciamma-O'Brien, E.; Smith, M. A.; Somogyi, A.; Szopa, C.; Thissen, R.; Vuitton, V.

2010-10-01

Titan has been a subject of astrobiological interest since the Voyager spacecraft first revealed the diversity of the organic chemistry occurring in the atmosphere. However, it was not until the arrival of Cassini-Huygens that the chemical complexity of Titan's atmosphere was fully appreciated. The Cassini Plasma Spectrometer (CAPS) observed negative ions with m/z values up to 10,000 u/q at 950 km [1] and positive ions with m/z up to 400 u/q [2]. CAPS has also observed O+ flowing into Titan's atmosphere [3]. While Titan's atmosphere is relatively oxygen poor compared to terrestrial planets, CO is the fourth most abundant molecule in the atmosphere (˜50 ppm). The fact that the observed O+ flux is deposited in the region now known to contain large organic molecules leads to the exciting possibility that oxygen can be incorporated into these molecules resulting in the production of prebiotic molecules. In this work, Titan aerosol analogues (or "tholins") produced in PAMPRE, a Titan atmosphere simulation experiment, have been analyzed in a very high resolution LTQ Orbitrap mass spectrometer. These PAMPRE tholins were produced by capacitively coupled RF discharge in a mixture of N2, CH4 and CO. The tholins were found to contain 18 molecules with molecular formulae corresponding to biological amino acids and nucleotide bases. GC-MS measurements have confirmed the structure of seven: adenine, cytosine, uracil, thymine, guanine, glycine and alanine. The production of prebiotic molecules under atmospheric conditions presents a new source of prebiotic material and may increase the range of planets where life could begin. [1] Coates AJ, et al. (2007). Geophys. Res. Lett. 34:22103- +. [2] Crary FJ, et al. (2009). Planet. Space Sci. 57:1847- 1856. [3] Hartle RE, et al. (2006). Geophys. Res. Lett. 33:8201-+.

Exobiology and life science

NASA Technical Reports Server (NTRS)

Mckay, C. P.

1987-01-01

The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) biogenic elements in the interstellar medium; (2) organic material in the solar nebula; (3) volatiles in comets and icy planetesimals; (4) pre-biotic atmospheric chemistry; (5) analysis of cosmic dust particles; and (6) microbial exposure. The required capabilities and desired hardware for the facility are detailed.

Organic chemical evolution

NASA Technical Reports Server (NTRS)

Chang, S.

1981-01-01

The course of organic chemical evolution preceding the emergence of life on earth is discussed based on evidence of processes occurring in interstellar space, the solar system and the primitive earth. Following a brief review of the equilibrium condensation model for the origin and evolution of the solar system, consideration is given to the nature and organic chemistry of interstellar clouds, comets, Jupiter, meteorites, Venus and Mars, and the prebiotic earth. Major issues to be resolved in the study of organic chemical evolution on earth are identified regarding condensation and accretion in the solar nebula, early geological evolution, the origin and evolution of the atmosphere, organic production rates, organic-inorganic interactions, environmental fluctuations, phase separation and molecular selectivity.

Catalytic synthesis of biologically important metabolites from formaldehyde and ammonia as a putative way of their prebiotic emergence

NASA Astrophysics Data System (ADS)

Delidovich, Irina; Taran, Oxana; Simonov, Alexander; Parmon, Valentin

The modern `RNA-world' theory considering the primary life as a system of self-replicating informational and catalytic oligomers is the most widespread hypothesis of life's origin. At the same time an alternative major theory antithetic to the genetic one exists. It is based on the primary formation of important metabolites and building blocks of biopolymers and appearance of the primordial autocatalytic cycles in geochemical environment. [1]. Encouraged by this theory, we suggest the putative emergence pathways to biologically relevant metabolites from simple precursors: formaldehyde (FA) and ammonia, which are known to be present in the interstellar space [2]. Based on our earlier [3, 4] and novel findings as well as on the literature data [5, 6] the scheme of conjugate autocatalytic processes including photochemical condensation of FA yielding C-C bond and catalytic formation of pyruvaldehyde, pyruvic acid, sugars, aminoacids catalyzed by minerals (aluminum silicate, phoshates) and by aminoacids themselves is proposed. Acetaldehyde, glyoxal, glycol-and glyceraldehydes (GA and GCA) were identified in this work as products of photolysis of FA aqueous solution with summary selectivity up to 20% and can serve as substrates for the synthesis of more complex organic compounds. In turn, alanine and pyruvic acid are formed during UV-irradiation of aqueous solution of acetaldehyde and ammonium nitrate [6]. Pyruvaldehyde formation from GCA and FA in presence of amino acids was observed by A. Weber [5]. Finally, we revealed the catalytic activity of zeolite HZSM-5-17 in acid form towards formation of pyruvaldehyde from GA and GCA in presence of alanine with the yield about 5%. This observation indicates that the assumption of catalytic activity of silica-alumina towards the synthesis of metabolites could be realistic. Prebiotic synthesis of sugars from lower monosacharides, as we showed earlier, could take place over phosphate catalysts [4]. The substrates and the products of the proposed scheme were detected in the interstellar space and meteorites [7, 8], evidencing of the possibility of its realization either on the Protoeath or in the protoplanet disk supplying the initial compounds for contemporary metabolism. Acknowledgements. The financial support of Program RAS, IP SB RAS N 10 is gratefully acknowledged. References 1. A. Eschenmoser, in "Origin of life. Chemical approach", Eds. P. Herdewijn, M.V. Kisakurek, Wiley-VCH, placeCityZurich, 2008 and refs therein. 2. D.A. Williams, J. Phys. Conf. 6, 1-17, 2005. 3. Pestunova, O., Simonov, A., Snytnikov, V., et al., Adv. Space Res. 36/2, 214-219, 2005. 4. Simonov, A., Pestunova, O., Matvienko, L., et al., Adv. Space Res. 40, 1634-1640, 2007. 5. A.L. Weber, Orig. Life Evol. Biosph. 31, 71-86, 2001. 6. T.A. Telegina, et. al., Journ. Evol. Biochim. i Fiziol. (Rus). 4/8, 429-434, 1977. 7. Hollis, J., Jewell, P., Lovas, F., et al., The Astrophysical Journal 613, L45-L48, 2004 8. Cooper, G., Kimmich, N., Belisle, W., et al., Nature 414(6866), 879, 2001.

Prebiotic chemistry in space; Proceedings of Symposia B1.4 and F3.3 of the COSPAR Scientific Assembly, 30th, Hamburg, Germany, July 11-21, 1994

NASA Technical Reports Server (NTRS)

1994-01-01

A two-part symposium was held concerning topics in Solar System chemistry. The first part covered the organic chemistry ofsmall bodies of the interplanetray medium. It produced papers on the evolution, spectral properties and composition of organic matter in comets, interplanetary dust and asteroids. The second part covered cryochemistry and exobiology in planetary atmospheres (gas giant planets and their satellites) and in various astronomical ices.

Growth of Organic Microspherules in Sugar-Ammonia Reactions

NASA Astrophysics Data System (ADS)

Weber, Arthur L.

2005-12-01

Reaction of small sugars of less than four carbons with ammonia in water yielded organic microspherules generally less than ten microns in size. The time course of microspherule growth was examined for the D-erythrose-ammonia reaction that yielded microspherules attached to the glass walls of containers. Measurements were made of the elemental composition and infrared spectrum of the microspherule material. These viscose semi-solid microspherules are viewed as possible containers for prebiotic catalytic processes relevant to the origin of life.

Value-added prebiotic GGMO oligosaccharides from a high-volume molasses by-product of pine fiber board manufacture

USDA-ARS?s Scientific Manuscript database

"Prebiotics" are substances that enhance the growth of beneficial bacteria in the gastrointestinal tract of host animals. To be of value, prebiotics must provide a selective nutrient source for desirable gut bacteria, especially Bifidobacterium, while reducing the incidence of undesirable bacteria ...

Commercial probiotic bacteria and prebiotic carbohydrates: a fundamental study on prebiotics uptake, antimicrobials production and inhibition of pathogens.

PubMed

Cruz-Guerrero, Alma; Hernández-Sánchez, Humberto; Rodríguez-Serrano, Gabriela; Gómez-Ruiz, Lorena; García-Garibay, Mariano; Figueroa-González, Ivonne

2014-08-01

Probiotics and prebiotics are among the most important functional food ingredients worldwide. The proven benefits of such ingredients to human health have encouraged the development of functional foods containing both probiotics and prebiotics. In this work, the production of antimicrobial compounds coupled to the uptake of commercial prebiotics by probiotic bacteria was investigated. The probiotic bacteria studied were able to take up commercial prebiotic carbohydrates to the same or higher extent than that observed for lactose (control carbohydrate). The growth of probiotic bacteria was coupled to the production of antimicrobials such as short-chain fatty acids (SCFA), H2 O2 and bacteriocins. A higher production of antimicrobial compounds was recorded with Oligomate 55® compared with Regulact® and Frutafit® (3-5 and 10-115 times higher SCFA and H2 O2 production, respectively). The probiotic bacteria grown with Oligomate 55® also produced bacteriocins and other non-identified antimicrobial compounds. The antimicrobials produced by the probiotic bacteria inhibited up to 50% the growth of model pathogens such as Escherichia coli, Listeria innocua and Micrococcus luteus compared with control cultures. The results here obtained are useful for the adequate selection of probiotic/prebiotics pairs and therefore in the development of efficient functional foods. © 2013 Society of Chemical Industry.

IMMUNO-MODULATORY PROPERTIES OF PREBIOTICS EXTRACTED FROM vernonia amygdalina.

PubMed

Im, Ezeonu; Ae, Asuquo; Bn, Ukwah; Po, Ukoha

2016-01-01

Vernonia amygdalina , commonly called bitter-leaf, is widely consumed in many parts of Africa, and Nigeria, in particular. The leaf extract has been reported to have antimicrobial, anti-plasmodial, anti-helminthic, as well as prebiotic properties, but its immuno-modulatory effects have not been well-studied, neither have the prebiotics been identified. This study evaluated the immuno-modulatory properties of the aqueous leaf extract and identified the prebiotic components. The immuno-modulatory potential was evaluated by monitoring the effects of oral administration of the extract on immunological, haematological and lipid profiles of Rattus norvegicus , while the prebiotic components were identified by thin layer chromatography (TLC), following liquid-liquid fractionation of the extract. Consumption of the extract caused significant increases in CD4+-, white blood cell-, total lymphocyte- and high density lipid (HDL) counts; decreases in low density lipid (LDL) and triglycerides and no significant effect on haemoglobin (Hb) and packed cell volume (PCV) in the blood of test animals. The water-soluble fraction of the extract contained most of the phyto-constituents of the extract and Thin Layer Chromatographic analysis of the fraction revealed the presence of fructo-oligosaccharide and galacto-oligosaccharide prebiotics. The results from this study have shown that the aqueous leaf extract of V. amygdalina has positive immune-modulatory and haematologic effects and contains some important prebiotic compounds.

Clinical Effects of Prebiotics in Pediatric Population.

PubMed

Orel, Rok; Reberšak, Lea Vodušek

2016-12-15

Prebiotics are non-digestible components of food that in a selective manner trigger the expansion of microbes in the gut with valuable effects for the health of the host. In our document, current literature pertaining to the clinical effects of the use of prebiotics for the treatment and prevention of some common pediatric pathology such as infantile colic, constipation, absorption of minerals, weight gain, diarrhea, respiratory infections, and eczema is reviewed. Data was collected through search of the MEDLINE, PubMed, UpToDate, Cochrane Database of Systemic Reviews, and the Cochrane Controlled Trials Register database as well as through references from relevant articles, all until September 2015. However, only the results of publications with adequate methodological quality were included. Prebiotics seem to be very appealing in treatment of many clinical conditions, explicitly in the fight against constipation, poor weight gain in preterm infants, and eczema in atopic children. In contrast to probiotics, the evidence of true clinical efficacy of prebiotics, supported with exact type and dose information are rather sparse, and there are a limited number of randomized controlled trials concerning prebiotics in children, especially beyond the age of infancy. Large well-designed, controlled, confirmatory clinical trials are required, using commercially available products, to help healthcare providers in making an appropriate decision concerning the appropriate use of prebiotics in different conditions.

Probiotics and prebiotics in prevention and treatment of diseases in infants and children.

PubMed

Vandenplas, Yvan; Veereman-Wauters, Genevieve; De Greef, Elisabeth; Peeters, Stefaan; Casteels, Ann; Mahler, Tania; Devreker, Thierry; Hauser, Bruno

2011-01-01

To evaluate the impact of probiotics and prebiotics on the health of children. MEDLINE and LILACS were searched for relevant English and French-language articles. Human milk is rich in prebiotic oligosaccharides and may contain some probiotics. No data suggest that addition of probiotics to infant formula may be harmful, but evidence of its efficacy is insufficient for its recommendation. Since data suggest that addition of specific prebiotic oligosaccharides may reduce infections and atopy in healthy infants, their addition to infant formula seems reasonable. Long-term health benefits of pro- and prebiotics on the developing immune system remain to be proven. Selected probiotics reduce the duration of infectious diarrhea by 1 day, but evidence in prevention is lacking, except in antibiotic-associated diarrhea. Some specific probiotics prevent necrotizing enterocolitis, and other microorganisms may be beneficial in Helicobacter pylori gastritis and in infantile colic. Evidence is insufficient to recommend probiotics in prevention and treatment of atopic dermatitis. The use of probiotics in constipation, irritable bowel syndrome, inflammatory bowel disease, and extra-intestinal infections requires more studies. Duration of administration, microbial dosage, and species used need further validation for both pro- and prebiotics. Unjustified health claims are a major threat for the pro- and prebiotic concept.

Chirality, photochemistry and the detection of amino acids in interstellar ice analogues and comets.

PubMed

Evans, Amanda C; Meinert, Cornelia; Giri, Chaitanya; Goesmann, Fred; Meierhenrich, Uwe J

2012-08-21

The primordial appearance of chiral amino acids was an essential component of the asymmetric evolution of life on Earth. In this tutorial review we will explore the original life-generating, symmetry-breaking event and summarise recent thoughts on the origin of enantiomeric excess in the universe. We will then highlight the transfer of asymmetry from chiral photons to racemic amino acids and elucidate current experimental data on the photochemical synthesis of amino and diamino acid structures in simulated interstellar and circumstellar ice environments. The chirality inherent within actual interstellar (cometary) ice environments will be considered in this discussion: in 2014 the Rosetta Lander Philae onboard the Rosetta space probe is planned to detach from the orbiter and soft-land on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko. It is equipped for the in situ enantioselective analysis of chiral prebiotic organic species in cometary ices. The scientific design of this mission will therefore be presented in the context of analysing the formation of amino acid structures within interstellar ice analogues as a means towards furthering understanding of the origin of asymmetric biological molecules.

Kinetic conversion of CO to CH4 in the Solar System

NASA Technical Reports Server (NTRS)

Yung, Y. L.; Allen, M.; Pinto, J. P.

1991-01-01

Some of the most interesting chemistry in the Solar System involves changes in the oxidation state of the simple carbon species. The chemical pathways for the conversion of CH4 to CO and CO2 are for the most part known. The reverse process, the reduction of CO to CH4, is, however, poorly understood. This is surprising in view of the importance of the reduction process in the chemistry of the Solar System. Recently we investigated the chemical kinetics of a hitherto unsuspected reaction. It is argued that the formation of the methoxy radical (CH3O) from H+H2CO may play an essential role in the reduction of CO to CH4. The rate coefficient for this reaction has been estimated using the approximate theory of J. Troe and transition state theory. We will discuss the implications of this reaction for the chemistry of CO on Jupiter, in the solar nebula, for interpreting the laboratory experiments of A. Bar-Nun and A. Shaviv and A. Bar-Nun and S. Chang, and for organic synthesis in the prebiotic terrestrial atmosphere. The possible relation of CO reduction in the solar nebula and polyoxymethylene observed in comet Halley will be discussed.

Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise

PubMed Central

German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M. V.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J. M.; de Lépinay, B. Mercier; Nakamura, K.; Seewald, J. S.; Smith, J. L.; Sylva, S. P.; Van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.

2010-01-01

Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the ∼110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at ∼5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity—all in close proximity. PMID:20660317

Sulfidic Anion Concentrations on Early Earth for Surficial Origins-of-Life Chemistry.

PubMed

Ranjan, Sukrit; Todd, Zoe R; Sutherland, John D; Sasselov, Dimitar D

2018-04-08

A key challenge in origin-of-life studies is understanding the environmental conditions on early Earth under which abiogenesis occurred. While some constraints do exist (e.g., zircon evidence for surface liquid water), relatively few constraints exist on the abundances of trace chemical species, which are relevant to assessing the plausibility and guiding the development of postulated prebiotic chemical pathways which depend on these species. In this work, we combine literature photochemistry models with simple equilibrium chemistry calculations to place constraints on the plausible range of concentrations of sulfidic anions (HS - , HSO 3 - , SO 3 2- ) available in surficial aquatic reservoirs on early Earth due to outgassing of SO 2 and H 2 S and their dissolution into small shallow surface water reservoirs like lakes. We find that this mechanism could have supplied prebiotically relevant levels of SO 2 -derived anions, but not H 2 S-derived anions. Radiative transfer modeling suggests UV light would have remained abundant on the planet surface for all but the largest volcanic explosions. We apply our results to the case study of the proposed prebiotic reaction network of Patel et al. ( 2015 ) and discuss the implications for improving its prebiotic plausibility. In general, epochs of moderately high volcanism could have been especially conducive to cyanosulfidic prebiotic chemistry. Our work can be similarly applied to assess and improve the prebiotic plausibility of other postulated surficial prebiotic chemistries that are sensitive to sulfidic anions, and our methods adapted to study other atmospherically derived trace species. Key Words: Early Earth-Origin of life-Prebiotic chemistry-Volcanism-UV radiation-Planetary environments. Astrobiology 18, xxx-xxx.

An Introduction to the Avian Gut Microbiota and the Effects of Yeast-Based Prebiotic-Type Compounds as Potential Feed Additives

PubMed Central

Roto, Stephanie M.; Rubinelli, Peter M.; Ricke, Steven C.

2015-01-01

The poultry industry has been searching for a replacement for antibiotic growth promoters in poultry feed as public concerns over the use of antibiotics and the appearance of antibiotic resistance has become more intense. An ideal replacement would be feed amendments that could eliminate pathogens and disease while retaining economic value via improvements on body weight and feed conversion ratios. Establishing a healthy gut microbiota can have a positive impact on growth and development of both body weight and the immune system of poultry while reducing pathogen invasion and disease. The addition of prebiotics to poultry feed represents one such recognized way to establish a healthy gut microbiota. Prebiotics are feed additives, mainly in the form of specific types of carbohydrates that are indigestible to the host while serving as substrates to select beneficial bacteria and altering the gut microbiota. Beneficial bacteria in the ceca easily ferment commonly studied prebiotics, producing short-chain fatty acids, while pathogenic bacteria and the host are unable to digest their molecular bonds. Prebiotic-like substances are less commonly studied, but show promise in their effects on the prevention of pathogen colonization, improvements on the immune system, and host growth. Inclusion of yeast and yeast derivatives as probiotic and prebiotic-like substances, respectively, in animal feed has demonstrated positive associations with growth performance and modification of gut morphology. This review will aim to link together how such prebiotics and prebiotic-like substances function to influence the native and beneficial microorganisms that result in a diverse and well-developed gut microbiota. PMID:26664957

The Sugar Model: Autocatalytic Activity of the Triose-Ammonia Reaction

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

2006-01-01

Reaction of triose sugars with ammonia under anaerobic conditions yielded autocatalytic products. The autocatalytic behavior of the products was examined by measuring the effect of the crude triose-ammonia reaction product on the kinetics of a second identical triose-ammonia reaction. The reaction product showed autocatalytic activity by increasing both the rate of disappearance of triose and the rate formation of pyruvaldehyde, the product of triose dehydration. This synthetic process is considered a reasonable model of origin-of-life chemistry because it uses plausible prebiotic substrates, and resembles modern biosynthesis by employing the energized carbon groups of sugars to drive the synthesis of autocatalytic molecules.

The Sugar Model: Autocatalytic Activity of the Triose Ammonia Reaction

NASA Astrophysics Data System (ADS)

Weber, Arthur L.

2007-04-01

Reaction of triose sugars with ammonia under anaerobic conditions yielded autocatalytic products. The autocatalytic behavior of the products was examined by measuring the effect of the crude triose ammonia reaction product on the kinetics of a second identical triose ammonia reaction. The reaction product showed autocatalytic activity by increasing both the rate of disappearance of triose and the rate of formation of pyruvaldehyde, the product of triose dehydration. This synthetic process is considered a reasonable model of origin-of-life chemistry because it uses plausible prebiotic substrates, and resembles modern biosynthesis by employing the energized carbon groups of sugars to drive the synthesis of autocatalytic molecules.

Acyl silicates and acyl aluminates as activated intermediates in peptide formation on clays

NASA Technical Reports Server (NTRS)

White, D. H.; Kennedy, R. M.; Macklin, J.

1984-01-01

Glycine reacts with heating on dried clays and other minerals to give peptides in much better yield than in the absence of mineral. This reaction was proposed to occur by way of an activated intermediate such as an acyl silicate or acyl aluminate analogous to acyl phosphates involved in several biochemical reactions including peptide bond synthesis. The proposed mechanism has been confirmed by trapping the intermediate, as well as by direct spectroscopic observation of a related intermediate. The reaction of amino acids on periodically dried mineral surfaces represents a widespead, geologically realistic setting for prebiotic peptide formation via in situ activation.

Probiotics, prebiotics, and microencapsulation: A review.

PubMed

Sarao, Loveleen Kaur; Arora, M

2017-01-22

The development of a suitable technology for the production of probiotics is a key research for industrial production, which should take into account the viability and the stability of the organisms involved. Microbial criteria, stress tolerance during processing, and storage of the product constitute the basis for the production of probiotics. Generally, the bacteria belonging to the genera Lactobacillus and Bifidobacterium have been used as probiotics. Based on their positive qualities, probiotic bacteria are widely used in the production of food. Interest in the incorporation of the probiotic bacteria into other products apart from dairy products has been increasing and represents a great challenge. The recognition of dose delivery systems for probiotic bacteria has also resulted in research efforts aimed at developing probiotic food outside the dairy sector. Producing probiotic juices has been considered more in the recent years, due to an increased concern in personal health of consumers. This review focuses on probiotics, prebiotics, and the microencapsulation of living cells.

Prebiotic and Probiotic Regulation of Bone Health: Role of the Intestine and its Microbiome

PubMed Central

McCabe, Laura; Britton, Robert A.; Parameswaran, Narayanan

2015-01-01

Recent advances in our understanding of how the intestinal microbiome contributes to health and disease have generated great interest in developing strategies for modulating the abundance of microbes and/or their activity to improve overall human health and prevent pathologies such as osteoporosis. Bone is an organ that the gut has long been known to regulate through absorption of calcium, the key bone mineral. However, it is clear that modulation of the gut and its microbiome can affect bone density and strength in a variety of animal models (zebra fish, rodents, chicken) and humans. This is demonstrated in studies ablating the microbiome through antibiotic treatment or using germ-free mouse conditions as well as in studies modulating the microbiome activity and composition through prebiotic and/or probiotic treatment. This review will discuss recent developments in this new and exciting area. PMID:26419466

Interaction of aromatic amines with iron oxides: implications for prebiotic chemistry.

PubMed

Shanker, Uma; Singh, Gurinder; Kamaluddin

2013-06-01

The interaction of aromatic amines (aniline, p-chloroaniline, p-toludine and p-anisidine) with iron oxides (goethite, akaganeite and hematite) has been studied. Maximum uptake of amines was observed around pH 7. The adsorption data obtained at neutral pH were found to follow Langmuir adsorption. Anisidine was found to be a better adsorbate probably due to its higher basicity. In alkaline medium (pH > 8), amines reacted on goethite and akaganeite to give colored products. Analysis of the products by GC-MS showed benzoquinone and azobenzene as the reaction products of aniline while p-anisidine afforded a dimer. IR analysis of the amine-iron oxide hydroxide adduct suggests that the surface acidity of iron oxide hydroxides is responsible for the interaction. The present study suggests that iron oxide hydroxides might have played a role in the stabilization of organic molecules through their surface activity and in prebiotic condensation reactions.

Probiotics and prebiotics in inflammatory bowel disease: microflora 'on the scope'.

PubMed

Damaskos, Dimitrios; Kolios, George

2008-04-01

The intestinal microflora is a large bacterial community that colonizes the gut, with a metabolic activity equal to an organ and various functions that affect the physiology and pathology of the host's mucosal immune system. Intestinal bacteria are useful in promotion of human health, but certain components of microflora, in genetically susceptible individuals, contribute to various pathological disorders, including inflammatory bowel disease. Clinical and experimental observations indicate an imbalance in protective and harmful microflora components in these disorders. Manipulation of gut flora to enhance its protective and beneficial role represents a promising field of new therapeutic strategies of inflammatory bowel disease. In this review, we discuss the implication of gut flora in the intestinal inflammation that justifies the role of probiotics and prebiotics in the prevention and treatment of inflammatory bowel disease and we address the evidence for therapeutic benefits from their use in experimental models of colitis and clinical trials.

Effects of dietary Aspergillus meal prebiotic on turkey poults production parameters and bone qualities

USDA-ARS?s Scientific Manuscript database

The objective of this study was to evaluate the effects of dietary Aspergillus meal (AM), a prebiotic on performance and bone parameters of neonatal turkey poults. Prebiotics are nondigestible food ingredients that beneficially affect the host and have been shown to stimulate calcium and magnesium a...

Top-down systems biology integration of conditional prebiotic modulated transgenomic interactions in a humanized microbiome mouse model

PubMed Central

Martin, Francois-Pierre J; Wang, Yulan; Sprenger, Norbert; Yap, Ivan K S; Rezzi, Serge; Ramadan, Ziad; Peré-Trepat, Emma; Rochat, Florence; Cherbut, Christine; van Bladeren, Peter; Fay, Laurent B; Kochhar, Sunil; Lindon, John C; Holmes, Elaine; Nicholson, Jeremy K

2008-01-01

Gut microbiome–host metabolic interactions affect human health and can be modified by probiotic and prebiotic supplementation. Here, we have assessed the effects of consumption of a combination of probiotics (Lactobacillus paracasei or L. rhamnosus) and two galactosyl-oligosaccharide prebiotics on the symbiotic microbiome–mammalian supersystem using integrative metabolic profiling and modeling of multiple compartments in germ-free mice inoculated with a model of human baby microbiota. We have shown specific impacts of two prebiotics on the microbial populations of HBM mice when co-administered with two probiotics. We observed an increase in the populations of Bifidobacterium longum and B. breve, and a reduction in Clostridium perfringens, which were more marked when combining prebiotics with L. rhamnosus. In turn, these microbial effects were associated with modulation of a range of host metabolic pathways observed via changes in lipid profiles, gluconeogenesis, and amino-acid and methylamine metabolism associated to fermentation of carbohydrates by different bacterial strains. These results provide evidence for the potential use of prebiotics for beneficially modifying the gut microbial balance as well as host energy and lipid homeostasis. PMID:18628745

Prebiotics and synbiotics: dietary strategies for improving gut health.

PubMed

Krumbeck, Janina A; Maldonado-Gomez, Maria X; Ramer-Tait, Amanda E; Hutkins, Robert W

2016-03-01

A wide range of dietary carbohydrates, including prebiotic food ingredients, fermentable fibers, and milk oligosaccharides, are able to produce significant changes in the intestinal microbiota. These shifts in the microbial community are often characterized by increased levels of bifidobacteria and lactobacilli. More recent studies have revealed that species of Faecalibacterium, Akkermansia, and other less well studied members may also be enriched. We review the implications of these recent studies on future design of prebiotics and synbiotics to promote gastrointestinal health. Investigations assessing the clinical outcomes associated with dietary modification of the gut microbiota have shown systemic as well as specific health benefits. Both prebiotic oligosaccharides comprised of a linear arrangement of simple sugars, as well as fiber-rich foods containing complex carbohydrates, have been used in these trials. However, individual variability and nonresponding study participants can make the outcome of dietary interventions less predictable. In contrast, synergistic synbiotics containing prebiotics that specifically stimulate a cognate probiotic provide additional options for personalized gut therapies. This review describes recent research on how prebiotics and fermentable fibers can influence the gut microbiota and result in improvements to human health.

Alginate coating as carrier of oligofructose and inulin and to maintain the quality of fresh-cut apples.

PubMed

Rössle, Christian; Brunton, Nigel; Gormley, Ronan T; Wouters, Rudy; Butler, Francis

2011-01-01

The aim of this study was to apply an edible coating containing prebiotics such as oligofructose and inulin to fresh-cut apple wedges. An assessment of the quality, sensory, polyphenol, and volatile attributes of coated and uncoated fresh-cut apple wedges was also undertaken. Fructan analysis showed that all prebiotics remained stable over the 14-d storage period and an intake of 100 g of apple supplies 1 to 3 g of prebiotics. Browning index, firmness, acidity remained stable throughout the 14 d compared to the control while applying prebiotic coatings resulted in an increase in soluble solids. Sensory and visual assessment indicated acceptable quality of apple wedges coated with prebiotics. HPLC analysis showed that levels of polyphenolic compounds were more stable in coated apple wedges (without prebiotic inclusions) than in uncoated control apples. No difference was found between O(2) and CO(2) headspace concentration of coated and uncoated samples. Significant differences (P < 0.001) were found for headspace volatile production between the samples. Most coated samples showed lower volatile production in the headspace than uncoated samples.

Antihypertensive Properties of Plant-Based Prebiotics

PubMed Central

Yeo, Siok-Koon; Ooi, Lay-Gaik; Lim, Ting-Jin; Liong, Min-Tze

2009-01-01

Hypertension is one of the major risk factors for cardiovascular disease. Although various drugs for its treatment have been synthesized, the occurring side effects have generated the need for natural interventions for the treatment and prevention of hypertension. Dietary intervention such as the administration of prebiotics has been seen as a highly acceptable approach. Prebiotics are indigestible food ingredients that bypass digestion and reach the lower gut as substrates for indigenous microflora. Most of the prebiotics used as food adjuncts, such as inulin, fructooligosaccharides, dietary fiber and gums, are derived from plants. Experimental evidence from recent studies has suggested that prebiotics are capable of reducing and preventing hypertension. This paper will discuss some of the mechanisms involved, the evidence generated from both in-vitro experiments and in-vivo trials and some controversial findings that are raised. PMID:20111692

Potential Role of Inorganic Confined Environments in Prebiotic Phosphorylation.

PubMed

Dass, Avinash Vicholous; Jaber, Maguy; Brack, André; Foucher, Frédéric; Kee, Terence P; Georgelin, Thomas; Westall, Frances

2018-03-05

A concise outlook on the potential role of confinement in phosphorylation and phosphate condensation pertaining to prebiotic chemistry is presented. Inorganic confinement is a relatively uncharted domain in studies concerning prebiotic chemistry, and even more so in terms of experimentation. However, molecular crowding within confined dimensions is central to the functioning of contemporary biology. There are numerous advantages to confined environments and an attempt to highlight this fact, within this article, has been undertaken, keeping in context the limitations of aqueous phase chemistry in phosphorylation and, to a certain extent, traditional approaches in prebiotic chemistry.

Potential Role of Inorganic Confined Environments in Prebiotic Phosphorylation

PubMed Central

Jaber, Maguy; Brack, André; Foucher, Frédéric; Kee, Terence P.; Westall, Frances

2018-01-01

A concise outlook on the potential role of confinement in phosphorylation and phosphate condensation pertaining to prebiotic chemistry is presented. Inorganic confinement is a relatively uncharted domain in studies concerning prebiotic chemistry, and even more so in terms of experimentation. However, molecular crowding within confined dimensions is central to the functioning of contemporary biology. There are numerous advantages to confined environments and an attempt to highlight this fact, within this article, has been undertaken, keeping in context the limitations of aqueous phase chemistry in phosphorylation and, to a certain extent, traditional approaches in prebiotic chemistry. PMID:29510574

Probiotics, Prebiotics, and Synbiotics for the Treatment and Prevention of Adult Dermatological Diseases.

PubMed

Notay, Manisha; Foolad, Negar; Vaughn, Alexandra R; Sivamani, Raja K

2017-12-01

Probiotic, prebiotic, and synbiotic supplementation is becoming more prevalent nowadays. Clinical studies have demonstrated some of the medical benefits of probiotics, prebiotics, and synbiotics within dermatology but an evidence-based review of their effects in adults is needed. The aim of this study was to identify evidence for the use of supplementation with probiotics, prebiotics, or synbiotics for the prevention and treatment of dermatological diseases in adults. We conducted a search of the Ovid MEDLINE, Cochrane Central Register of Controlled trials and EMBASE electronic databases from 1 January 1946 to 11 January 2017. Trials examining supplementation in the treatment of dermatological diseases using oral or topical probiotics, synbiotics, and prebiotics in adults over the age of 18 years were selected. Of 315 articles, 12 met the inclusion criteria. Nutritional supplementation with probiotics and prebiotics was shown to improve atopic dermatitis (AD) symptomatology, quality of life, or clinical severity in six of nine studies. One study in psoriasis was shown to improve inflammatory markers, and one study suggested that probiotics could be used as adjunctive therapy in the treatment of acne. Preliminary studies are optimistic for the use of some strains of probiotics for symptomatic and clinical improvement in AD, and as adjunctive treatment with antibiotics for acne. Further research is necessary to better assess how probiotics and prebiotics may be used within dermatology.

Formation of Prebiotic Molecules in Interstellar and Cometary Ices

NASA Technical Reports Server (NTRS)

Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Dworkin, Jason; Gilette, J. Seb; Zare, Richard N.; DeVincenzi, D. (Technical Monitor)

2000-01-01

We report here on our lab studies of ice photochemistry of large organic molecules under cometary conditions. We focus on polycyclic aromatic hydrocarbons (PAHs), their photoproducts, and their similarities to molecules seen in living systems today. We note that these kinds of compounds are seen in meteorites and we propose an explanation for both their formation and their observed deuterium enrichments.

Biotic Abstract Dual Automata (BiADA): a novel tool for studying the evolution of porebiotic order (and the origin of life).

PubMed

Cimpoiasu, Vily M; Popa, Radu

2012-12-01

Biotic Abstract Dual Automata (BiADA), a novel simulation concept for studying the evolution of prebiotic order, has four main attributes. (1) The energy of each form of organization is the sum of two stocks: entropy-associated energy (E(s)) and free energy (E(g)), with dissimilar meaning, energy conductive, and energy exchange properties; (2) E(s) and E(g) have user-defined absolute values and are not derived from the relative thermodynamic parameters standard entropy and standard Gibbs free energy; (3) BiADA analyzes changes in both units of transformation and units of organization; and (4) BiADA-based models analyze forward and reverse transformations separately and the brut production of forms of organization. We discuss quantitative relationships between energy, information, and order parameters proposed in BiADA-based simulations. The example we show is that of a simple system with two forms of organization. The model monitors the energy flow and budget, the evolution of order and information capacity, and the energy cost of producing and maintaining the system's state. We show the effect of six prebiotic factors on the evolution of order and energy dissipative potential of the system. These are the initial state of the system, energy availability, the intrinsic energy conductivity, catalysis of "A to B" transformations, B autocatalysis, and the terminal heat sink. We discuss benefits of employing BiADA principles in the study of the origin of order in more complex networks.

H2-rich fluids from serpentinization: geochemical and biotic implications.

PubMed

Sleep, N H; Meibom, A; Fridriksson, Th; Coleman, R G; Bird, D K

2004-08-31

Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impact. This process formed some of the ferric iron in the Earth's mantle. For the rest of Earth's history, serpentinites covered only a small fraction of the Earth's surface but were an important prebiotic and biotic environment. Extant methanogens react H2 with CO2 to form methane. This is a likely habitable environment on large silicate planets. The catalytic properties of FeNi3 allow complex organic compounds to form within serpentinite and, when mixed with atmospherically produced complex organic matter and waters that circulated through basalts, constitutes an attractive prebiotic substrate. Conversely, inorganic catalysis of methane by FeNi3 competes with nascent and extant life. Copyright 2004 The National Academy of Sciencs of the USA

Conversion and Extraction of Insoluble Organic Materials in Meteorites

NASA Technical Reports Server (NTRS)

Locke, Darren R.; Burton, Aaron S.; Niles, Paul B.

2016-01-01

We endeavor to develop and implement methods in our laboratory to convert and extract insoluble organic materials (IOM) from low car-bon bearing meteorites (such as ordinary chondrites) and Precambrian terrestrial rocks for the purpose of determining IOM structure and prebiotic chemistries preserved in these types of samples. The general scheme of converting and extracting IOM in samples is summarized in Figure 1. First, powdered samples are solvent extracted in a micro-Soxhlet apparatus multiple times using solvents ranging from non-polar to polar (hexane - non-polar, dichloromethane - non-polar to polar, methanol - polar protic, and acetonitrile - polar aprotic). Second, solid residue from solvent extractions is processed using strong acids, hydrochloric and hydrofluoric, to dissolve minerals and isolate IOM. Third, the isolated IOM is subjected to both thermal (pyrolysis) and chemical (oxidation) degradation to release compounds from the macromolecular material. Finally, products from oxidation and pyrolysis are analyzed by gas chromatography - mass spectrometry (GCMS). We are working toward an integrated method and analysis scheme that will allow us to determine prebiotic chemistries in ordinary chondrites and Precambrian terrestrial rocks. Powerful techniques that we are including are stepwise, flash, and gradual pyrolysis and ruthenium tetroxide oxidation. More details of the integrated scheme will be presented.

Organic Molecules in Meteorites

NASA Astrophysics Data System (ADS)

Martins, Zita

2015-08-01

Carbonaceous meteorites are primitive samples from the asteroid belt, containing 3-5wt% organic carbon. The exogenous delivery of organic matter by carbonaceous meteorites may have contributed to the organic inventory of the early Earth. The majority (>70%) of the meteoritic organic material consist of insoluble organic matter (IOM) [1]. The remaining meteoritic organic material (<30%) consists of a rich organic inventory of soluble organic compounds, including key compounds important in terrestrial biochemistry [2-4]. Different carbonaceous meteorites contain soluble organic molecules with different abundances and distributions, which may reflect the extension of aqueous alteration or thermal metamorphism on the meteorite parent bodies. Extensive aqueous alteration on the meteorite parent body may result on 1) the decomposition of α-amino acids [5, 6]; 2) synthesis of β- and γ-amino acids [2, 6-9]; 3) higher relative abundances of alkylated polycyclic aromatic hydrocarbons (PAHs) [6, 10]; and 4) higher L-enantiomer excess (Lee) value of isovaline [6, 11, 12].The soluble organic content of carbonaceous meteorites may also have a contribution from Fischer-Tropsch/Haber-Bosch type gas-grain reactions after the meteorite parent body cooled to lower temperatures [13, 14].The analysis of the abundances and distribution of the organic molecules present in meteorites helps to determine the physical and chemical conditions of the early solar system, and the prebiotic organic compounds available on the early Earth.[1] Cody and Alexander (2005) GCA 69, 1085. [2] Cronin and Chang (1993) in: The Chemistry of Life’s Origin. pp. 209-258. [3] Martins and Sephton (2009) in: Amino acids, peptides and proteins in organic chemistry. pp. 1-42. [4] Martins (2011) Elements 7, 35. [5] Botta et al. (2007) MAPS 42, 81. [6] Martins et al. (2015) MAPS, in press. [7] Cooper and Cronin (1995) GCA 59, 1003. [8] Glavin et al. (2006) MAPS. 41, 889. [9] Glavin et al. (2011) MAPS 45, 1948. [10] Elsila et al. (2005) GCA 5, 1349. [11] Glavin and Dworkin (2009) PNAS 106, 5487. [12] Pizzarello et al. (2003) GCA 67, 1589. [13] Chan et al. (2012) MAPS. 47, 1502. [14] Burton et al. (2011) MAPS 46, 1703.

Formation of protocell-like vesicles in a thermal diffusion column.

PubMed

Budin, Itay; Bruckner, Raphael J; Szostak, Jack W

2009-07-22

Many of the properties of bilayer membranes composed of simple single-chain amphiphiles seem to be well-suited for a potential role as primitive cell membranes. However, the spontaneous formation of membranes from such amphiphiles is a concentration-dependent process in which a significant critical aggregate concentration (cac) must be reached. Since most scenarios for the prebiotic synthesis of fatty acids and related amphiphiles would result in dilute solutions well below the cac, the identification of mechanisms that would lead to increased local amphiphile concentrations is an important aspect of defining reasonable conditions for the origin of cellular life. Narrow, vertically oriented channels within the mineral precipitates of hydrothermal vent towers have previously been proposed to act as natural Clusius-Dickel thermal diffusion columns, in which a strong transverse thermal gradient concentrates dilute molecules through the coupling of thermophoresis and convection. Here we experimentally demonstrate that a microcapillary acting as a thermal diffusion column can concentrate a solution of oleic acid. Upon concentration, self-assembly of large vesicles occurs in regions where the cac is exceeded. We detected vesicle formation by fluorescence microscopy of encapsulated dye cargoes, which simultaneously concentrated in our channels. Our findings suggest a novel means by which simple physical processes could have led to the spontaneous formation of cell-like structures from a dilute prebiotic reservoir.

Three stages during the evolution of the genetic code. [Abstract only

NASA Technical Reports Server (NTRS)

Baumann, U.; Oro, J.

1994-01-01

A diversification of the genetic code based on the number of codons available for the proteinous amino acids is established. Three groups of amino acids during evolution of the code are distinguished. On the basis of their chemical complexity and a small codon number those amino acids emerging later in a translation process are derived. Both criteria indicate that His, Phe, Tyr, Cys and either Lys or Asn were introduced in the second stage, whereas the number of codons alone gives evidence that Trp and Met were introduced in the third stage. The amino acids of stage one use purines rich codons, thus purines have been retained in their third codon position. All the amino acids introduced in the second stage, in contrast, use pyrimidines in this codon position. A low abundance of pyrimidines during early translation is derived. This assumption is supported by experiments on non enzymatic replication and interactions of DNA hairpin loops with a complementary strand. A back extrapolation concludes a high purine content of the first nucleic acids which gradually decreased during their evolution. Amino acids independently available form prebiotic synthesis were thus correlated to purine rich codons. Conclusions on prebiotic replication are discussed also in the light of recent codon usage data.

Functional food addressing heart health: do we have to target the gut microbiota?

PubMed

Ryan, Paul M; Ross, Reynolds Paul; Fitzgerald, Gerald F; Caplice, Noel M; Stanton, Catherine

2015-11-01

Health promoting functional food ingredients for cardiovascular health are generally aimed at modulating lipid metabolism in consumers. However, significant advances have furthered our understanding of the mechanisms involved in development, progression, and treatment of cardiovascular disease. In parallel, a central role of the gut microbiota, both in accelerating and attenuating cardiovascular disease, has emerged. Modulation of the gut microbiota, by use of prebiotics and probiotics, has recently shown promise in cardiovascular disease prevention. Certain prebiotics can promote a short chain fatty acid profile that alters hormone secretion and attenuates cholesterol synthesis, whereas bile salt hydrolase and exopolysaccharide-producing probiotics have been shown to actively correct hypercholesterolemia. Furthermore, specific microbial genera have been identified as potential cardiovascular disease risk factors. This effect is attributed to the ability of certain members of the gut microbiota to convert dietary quaternary amines to trimethylamine, the primary substrate of the putatively atherosclerosis-promoting compound trimethylamine-N-oxide. In this respect, current research is indicating trimethylamine-depleting Achaea - termed Archeabiotics as a potential novel dietary strategy for promoting heart health. The microbiota offers a modifiable target, which has the potential to progress or prevent cardiovascular disease development. Whereas host-targeted interventions remain the standard, current research implicates microbiota-mediated therapies as an effective means of modulating cardiovascular health.

Detection of Macromolecular Fractions in HCN Polymers Using Electrophoretic and Ultrafiltration Techniques.

PubMed

Marín-Yaseli, Margarita R; Cid, Cristina; Yagüe, Ana I; Ruiz-Bermejo, Marta

2017-02-01

Elucidating the origin of life involves synthetic as well as analytical challenges. Herein, for the first time, we describe the use of gel electrophoresis and ultrafiltration to fractionate HCN polymers. Since the first prebiotic synthesis of adenine by Oró, HCN polymers have gained much interest in studies on the origins of life due to the identification of biomonomers and related compounds within them. Here, we demonstrate that macromolecular fractions with electrophoretic mobility can also be detected within HCN polymers. The migration of polymers under the influence of an electric field depends not only on their sizes (one-dimensional electrophoresis) but also their different isoelectric points (two-dimensional electrophoresis, 2-DE). The same behaviour was observed for several macromolecular fractions detected in HCN polymers. Macromolecular fractions with apparent molecular weights as high as 250 kDa were detected by tricine-SDS gel electrophoresis. Cationic macromolecular fractions with apparent molecular weights as high as 140 kDa were also detected by 2-DE. The HCN polymers synthesized were fractionated by ultrafiltration. As a result, the molecular weight distributions of the macromolecular fractions detected in the HCN polymers directly depended on the synthetic conditions used to produce these polymers. The implications of these results for prebiotic chemistry will be discussed. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Physical Principles and Extant Biology Reveal Roles for RNA-Containing Membraneless Compartments in Origins of Life Chemistry.

PubMed

Poudyal, Raghav R; Pir Cakmak, Fatma; Keating, Christine D; Bevilacqua, Philip C

2018-05-01

This Perspective focuses on RNA in biological and nonbiological compartments resulting from liquid-liquid phase separation (LLPS), with an emphasis on origins of life. In extant cells, intracellular liquid condensates, many of which are rich in RNAs and intrinsically disordered proteins, provide spatial regulation of biomolecular interactions that can result in altered gene expression. Given the diversity of biogenic and abiogenic molecules that undergo LLPS, such membraneless compartments may have also played key roles in prebiotic chemistries relevant to the origins of life. The RNA World hypothesis posits that RNA may have served as both a genetic information carrier and a catalyst during the origin of life. Because of its polyanionic backbone, RNA can undergo LLPS by complex coacervation in the presence of polycations. Phase separation could provide a mechanism for concentrating monomers for RNA synthesis and selectively partition longer RNAs with enzymatic functions, thus driving prebiotic evolution. We introduce several types of LLPS that could lead to compartmentalization and discuss potential roles in template-mediated non-enzymatic polymerization of RNA and other related biomolecules, functions of ribozymes and aptamers, and benefits or penalties imparted by liquid demixing. We conclude that tiny liquid droplets may have concentrated precious biomolecules and acted as bioreactors in the RNA World.

Prebiotic effects of bovine lactoferrin on specific probiotic bacteria.

PubMed

Chen, Po-Wen; Liu, Zhen-Shu; Kuo, Tai-Chen; Hsieh, Min-Chi; Li, Zhe-Wei

2017-04-01

Bovine lactoferrin (bLf) is a natural iron-binding protein and it has been suggested to be a prebiotic agent, but this finding remains inconclusive. This study explores the prebiotic potential of bLf in 14 probiotics. Initially, bLf (1-32 mg/mL) treatment showed occasional and slight prebiotic activity in several probiotics only during the late experimental period (48, 78 h) at 37 °C. We subsequently supposed that bLf exerts stronger prebiotic effects when probiotic growth has been temperately retarded. Therefore, we incubated the probiotics at different temperatures, namely 37 °C, 28 °C, room temperature (approximately 22-24 °C), and 22 °C, to retard or inhibit their growth. As expected, bLf showed more favorable prebiotic activity in several probiotics when their growth was partially retarded at room temperature. Furthermore, at 22 °C, the growth of Bifidobacterium breve, Lactobacillus coryniformis, L. delbrueckii, L. acidophilus, B. angulatum, B. catenulatum, and L. paraplantarum were completely blocked. Notably, these probiotics started regrowing in the presence of bLf (1-32 mg/mL) in a significant and dose-dependent manner. Accordingly, bLf significantly increased the growth of Pediococcus pentosaceus, L. rhamnosus, and L. paracasei (BCRC 17483; a locally isolated strain) when their growth was retarded by incubation at 22 °C. In conclusion, bLf showed inconsistent prebiotic activity in the 14 probiotics at 37 °C, but revealed strong prebiotic activity in 10 probiotic strains at 22 °C. Therefore, this study enables determining additional roles of Lf in probiotic strains, which can facilitate developing novel combinational approaches by simultaneously using Lf and specific probiotics.

In vitro prebiotic effects of seaweed polysaccharides

NASA Astrophysics Data System (ADS)

Chen, Xiaolin; Sun, Yuhao; Hu, Linfeng; Liu, Song; Yu, Huahua; Xing, Rong'e.; Li, Rongfeng; Wang, Xueqin; Li, Pengcheng

2017-09-01

Although prebiotic activities of alginate and agar oligosaccharides isolated from seaweeds have been reported, it remains unknown whether seaweed polysaccharides have prebiotic activity. In this study, we isolated polysaccharides from four species of seaweeds, such as Grateloupia filicina (GFP), Eucheuma spinosum (ESP), Ulva pertusa (UPP), and Ascophyllum nodosum (ANP), and characterized their structures and prebiotic effects in vitro. The results showed that these polysaccharides were different in total sugar and sulfate contents as well as monosaccharide composition. GFP and ESP significantly promoted bifidobacterium proliferation and 0.1% ESP and 0.4% GFP resulted in the highest proliferation rates of beneficial bacteria, whereas UPP and ANP inhibited the growth of beneficial bacteria at all tested concentrations (0.1%-0.5%). The different behaviors of the four seaweed-originated polysaccharides might be reflected by differences in monosaccharide composition and structure. Therefore, polysaccharides isolated from GFP and ESP could be utilized as prebiotics. However, more studies must be carried out in vivo.

Prebiotics as immunostimulants in aquaculture: a review.

PubMed

Song, Seong Kyu; Beck, Bo Ram; Kim, Daniel; Park, John; Kim, Jungjoon; Kim, Hyun Duk; Ringø, Einar

2014-09-01

Prebiotics are indigestible fibers that increase beneficial gut commensal bacteria resulting in improvements of the host's health. The beneficial effects of prebiotics are due to the byproducts generated from their fermentation by gut commensal bacteria. In this review, the direct effects of prebiotics on the innate immune system of fish are discussed. Prebiotics, such as fructooligosaccharide, mannanoligosaccharide, inulin, or β-glucan, are called immunosaccharides. They directly enhance innate immune responses including: phagocytic activation, neutrophil activation, activation of the alternative complement system, increased lysozyme activity, and more. Immunosaccharides directly activate the innate immune system by interacting with pattern recognition receptors (PRR) expressed on innate immune cells. They can also associate with microbe associated molecular patterns (MAMPs) to activate innate immune cells. However, the underlying mechanisms involved in innate immune cell activation need to be further explored. Many studies have indicated that immunosaccharides are beneficial to both finfish and shellfish. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mechanisms of Prebiotic Impact on Health

NASA Astrophysics Data System (ADS)

Steed, H.; Macfarlane, S.

Prebiotics were originally defined as non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activities of one or a limited number of bacteria in the colon, thereby improving host health (Gibson and Roberfroid, 1995). However, a more recent definition is that “A prebiotic is a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefits upon host wellbeing and health” (Gibson et al., 2004). The principal concept associated with both of these definitions is that the prebiotic has a selective effect on the microbiota that results in an improvement in the health of the host. Common prebiotics in use include inulins, fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), soya-oligosaccharides, xylo-oligosaccharides, pyrodextrins, isomalto-oligosaccharides and lactulose. The majority of studies carried out to date have focused on inulin, FOS and GOS (Macfarlane et al., 2008).

Prebiotics, probiotics, synbiotics, and the immune system: experimental data and clinical evidence.

PubMed

Frei, Remo; Akdis, Mübeccel; O'Mahony, Liam

2015-03-01

The intestinal immune system is constantly exposed to foreign antigens, which for the most part should be tolerated. Certain probiotics, prebiotics, and synbiotics are able to influence immune responses. In this review, we highlight the recent publications (within the last 2 years) that have substantially progressed this field. The immunological mechanisms underpinning probiotics, prebiotics, and synbiotics effects continue to be better defined with novel mechanisms being described for dendritic cells, epithelial cells, T regulatory cells, effector lymphocytes, natural killer T cells, and B cells. Many of the mechanisms being described are bacterial strain or metabolite specific, and should not be extrapolated to other probiotics or prebiotics. In addition, the timing of intervention seems to be important, with potentially the greatest effects being observed early in life. In this review, we discuss the recent findings relating to probiotics, prebiotics, and synbiotics, specifically their effects on immunological functions.

Stability of Lactobacillus rhamnosus GG in prebiotic edible films

PubMed Central

Soukoulis, Christos; Behboudi-Jobbehdar, Solmaz; Yonekura, Lina; Parmenter, Christopher; Fisk, Ian D.

2014-01-01

The concept of prebiotic edible films as effective vehicles for encapsulating probiotic living cells is presented. Four soluble fibres (inulin, polydextrose, glucose-oligosaccharides and wheat dextrin) were selected as prebiotic co-components of gelatine based matrices plasticised with glycerol and used for the immobilisation of Lactobacillusrhamnosus GG. The addition of prebiotics was associated with a more compact and uniform film structure, with no detectable interspaces or micropores; probiotic inclusion did not significantly change the structure of the films. Glucose-oligosaccharides and polydextrose significantly enhanced L. rhamnosus GG viability during air drying (by 300% and 75%, respectively), whilst a 33% and 80% reduction in viable counts was observed for inulin and wheat dextrin. Contrarily, inulin was the most effective at controlling the sub-lethal effects on L. rhamnosus GG during storage. However, in all cases the supplementation of edible films with prebiotics ameliorated the storage stability of L. rhamnosus GG. PMID:24767059

In vitro fermentation of prebiotics by Lactobacillus plantarum CFR 2194: selectivity, viability and effect of metabolites on β-glucuronidase activity.

PubMed

Arenahalli Ningegowda, Madhu; Siddalingaiya Gurudutt, Prapulla

2012-03-01

Prebiotic Fructooligosaccharides (FOS) escape metabolism in upper GI tract undergo microbial metabolism in colon and thereby influence the nature, type and number of intestinal microbiota to improve host's health. The present study focuses on the ability of Lactobacillus plantarum CFR 2194 to utilize FOS as a selective carbon and energy source. The effect of fermentative metabolites of L. plantarum on the β-glucuronidase was also investigated. A total of 16 strains of lactobacilli were assessed for their ability to ferment oligosaccharides. L. plantarum CFR 2194, an isolate from kanjika was found to utilize FOS effectively. Lactic acid was the main metabolic end product, followed by acetic acid, butyric acid, formic acid and ethanol. The inhibitory effects of these metabolites have been confirmed through the reduction of β-glucuronidase activity. L. plantarum when co-cultured with β-glucuronidase producing E. coli, in a basal media containing FOS as an energy source, could inhibit the growth of the pathogen during the course of fermentation. The results showed that L. plantarum CFR 2194 has the ability to utilize the prebiotic FOS as a selective carbon and energy source. The organism could inhibit the growth of the pathogen which produces β-glucuronidase and lowered its activity by the metabolites of FOS which indicates the probable use of L. plantarum through dietary intervention in combating colon carcinogenesis.

Extraterrestrial organic matter: a review

NASA Technical Reports Server (NTRS)

Irvine, W. M.

1998-01-01

We review the nature of the widespread organic material present in the Milky Way Galaxy and in the Solar System. Attention is given to the links between these environments and between primitive Solar System objects and the early Earth, indicating the preservation of organic material as an interstellar cloud collapsed to form the Solar System and as the Earth accreted such material from asteroids, comets and interplanetary dust particles. In the interstellar medium of the Milky Way Galaxy more than 100 molecular species, the bulk of them organic, have been securely identified, primarily through spectroscopy at the highest radio frequencies. There is considerable evidence for significantly heavier organic molecules, particularly polycyclic aromatics, although precise identification of individual species has not yet been obtained. The so-called diffuse interstellar bands are probably important in this context. The low temperature kinetics in interstellar clouds leads to very large isotopic fractionation, particularly for hydrogen, and this signature is present in organic components preserved in carbonaceous chondritic meteorites. Outer belt asteroids are the probable parent bodies of the carbonaceous chondrites, which may contain as much as 5% organic material, including a rich variety of amino acids, purines, pyrimidines, and other species of potential prebiotic interest. Richer in volatiles and hence less thermally processed are the comets, whose organic matter is abundant and poorly characterized. Cometary volatiles, observed after sublimation into the coma, include many species also present in the interstellar medium. There is evidence that most of the Earth's volatiles may have been supplied by a 'late' bombardment of comets and carbonaceous meteorites, scattered into the inner Solar System following the formation of the giant planets. How much in the way of intact organic molecules of potential prebiotic interest survived delivery to the Earth has become an increasingly debated topic over the last several years. The principal source for such intact organics was probably accretion of interplanetary dust particles of cometary origin.

Total calcium absorption is similar from infant formulas with and without prebiotics and exceeds that in human milk-fed infants

USDA-ARS?s Scientific Manuscript database

Our goal was to evaluate calcium absorption in infants fed a formula containing prebiotics (PF) and one without prebiotics (CF), and to compare calcium absorption from these formulas with a group of human milk-fed (HM) infants. A dual tracer stable isotope method was used to assess calcium absorptio...

Probiotics and prebiotics in dermatology.

PubMed

Baquerizo Nole, Katherine L; Yim, Elizabeth; Keri, Jonette E

2014-10-01

The rapid increase in the medical use of probiotics and prebiotics in recent years has confirmed their excellent safety profile. As immune modulators, they have been used in inflammatory skin conditions, such as atopic dermatitis. We review the literature regarding the use of probiotics and prebiotics in dermatology. Probiotics and prebiotics appear to be effective in reducing the incidence of atopic dermatitis in infants, but their role in atopic dermatitis treatment is controversial. Their role in acne, wound healing, and photoprotection is promising, but larger trials are needed before a final recommendation can be made. Copyright © 2014 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Prebiotics in healthy infants and children for prevention of acute infectious diseases: a systematic review and meta-analysis.

PubMed

Lohner, Szimonetta; Küllenberg, Daniela; Antes, Gerd; Decsi, Tamás; Meerpohl, Joerg J

2014-08-01

Prebiotics, defined as nondigestible dietary ingredients resistant to gastric acidity and fermented by the intestinal flora, are used to positively influence the composition of intestinal flora, thereby promoting health benefits. The objective of this systematic review was to assess the efficacy of prebiotics in the prevention of acute infectious diseases in children. A systematic literature search was conducted using the Ovid Medline, Scopus, Web of Science, and Cochrane Library's Central databases. Finally, five randomized controlled trials, all of them investigating infants and children 0-24 months of age, were included in the review. Pooled estimates from three studies revealed a statistically significant decrease in the number of infectious episodes requiring antibiotic therapy in the prebiotic group as compared with the placebo group (rate ratio 0.68; 95% confidence interval 0.61-0.77). Studies available indicate that prebiotics may also be effective in decreasing the rate of overall infections in infants and children 0-24 months of age. Further studies in the age group 3-18 years are required to determine whether prebiotics can be considered for the prevention of acute infectious diseases in the older pediatric population. © 2014 International Life Sciences Institute.

Prebiotic inulin supplementation modulates the immune response and restores gut morphology in Giardia duodenalis-infected malnourished mice.

PubMed

Shukla, Geeta; Bhatia, Ruchika; Sharma, Anuj

2016-11-01

Malnutrition induces a state of growth retardation and immunologic depression, enhancing the host susceptibility to various infections. In the present study, it was observed that prebiotic supplementation either prior or simultaneously with Giardia infection in malnourished mice significantly reduced the severity of giardiasis and increased the body and small intestine mass, along with increased lactobacilli counts in faeces compared with malnourished-Giardia-infected mice. More specifically, prebiotic supplementation significantly increased the levels of anti-giardial IgG and IgA antibodies and anti-inflammatory cytokines IL-6 and IL-10 and reduced the pro-inflammatory cytokine TNF-α, along with increased levels of nitric oxide in both the serum and intestinal fluid of malnourished-prebiotic-Giardia-infected mice compared with malnourished-Giardia-infected mice. Histopathology and scanning electron microscopy of the small intestine also revealed less cellular and mucosal damage in the microvilli of prebiotic-supplemented malnourished-Giardia-infected mice compared with severely damaged mummified and blunted villi of malnourished-Giardia-infected mice. This is the first study to report that prebiotic supplementation modulated the gut morphology and improved the immune status even in malnourished-Giardia-infected mice.

Probiotics, prebiotics infant formula use in preterm or low birth weight infants: a systematic review

PubMed Central

2012-01-01

Background Previous reviews (2005 to 2009) on preterm infants given probiotics or prebiotics with breast milk or mixed feeds focused on prevention of Necrotizing Enterocolitis, sepsis and diarrhea. This review assessed if probiotics, prebiotics led to improved growth and clinical outcomes in formula fed preterm infants. Methods Cochrane methodology was followed using randomized controlled trials (RCTs) which compared preterm formula containing probiotic(s) or prebiotic(s) to conventional preterm formula in preterm infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Heterogeneity was assessed by visual inspection of forest plots and a chi2 test. An I2 test assessed inconsistencies across studies. I2> 50% represented substantial heterogeneity. Results Four probiotics studies (N=212), 4 prebiotics studies (N=126) were included. Probiotics: There were no significant differences in weight gain (MD 1.96, 95% CI: -2.64 to 6.56, 2 studies, n=34) or in maximal enteral feed (MD 35.20, 95% CI: -7.61 to 78.02, 2 studies, n=34), number of stools per day increased significantly in probiotic group (MD 1.60, 95% CI: 1.20 to 2.00, 1 study, n=20). Prebiotics: Galacto-oligosaccharide / Fructo-oligosaccharide (GOS/FOS) yielded no significant difference in weight gain (MD 0.04, 95% CI: -2.65 to 2.73, 2 studies, n=50), GOS/FOS yielded no significant differences in length gain (MD 0.01, 95% CI: -0.03 to 0.04, 2 studies, n=50). There were no significant differences in head growth (MD −0.01, 95% CI: -0.02 to 0.00, 2 studies, n=76) or age at full enteral feed (MD −0.79, 95% CI: -2.20 to 0.61, 2 studies, n=86). Stool frequency increased significantly in prebiotic group (MD 0.80, 95% CI: 0.48 to 1.1, 2 studies, n=86). GOS/FOS and FOS yielded higher bifidobacteria counts in prebiotics group (MD 2.10, 95% CI: 0.96 to 3.24, n=27) and (MD 0.48, 95% CI: 0.28 to 0.68, n=56). Conclusions There is not enough evidence to state that supplementation with probiotics or prebiotics results in improved growth and clinical outcomes in exclusively formula fed preterm infants. PMID:22928998

Harnessing the Efficiency of 0(1D) Insertion Reactions for Prebiotic Astrochemistry

NASA Astrophysics Data System (ADS)

Widicus Weaver, Susanna

We propose a THz spectroscopic study of the small prebiotic molecules aminomethanol, methanediol, and methoxymethanol. These target molecules are predicted as the dominant products of photo-driven grain surface chemistry in interstellar environments, and are precursors to important prebiotic molecules like sugars and amino acids. These molecules are also expected to be major contributors to the spectral line density in the submillimeter spectral surveys from the Herschel and SOFIA observatories. We will use our custom mixing source to produce these molecules through O(1D) insertion reactions with the precursor molecules methyl amine, methanol, and dimethyl ether, respectively. We will then record their rotational spectra across the THz frequency range using our existing submillimeter spectrometer. This research will increase the science return from NASA missions because the target molecules serve as tracers of the simplest organic chemistry that can occur in starforming regions. This chemistry begins with methanol, which is the predominant organic molecule observed in interstellar ices. Methanol photodissociation leads to small organic radicals such as CH3O, CH2OH, and CH3. These radicals can undergo combination reactions on interstellar ices to form many of the complex organic molecules that are routinely observed in star-forming regions. Our target molecules aminomethanol, methanediol, and methoxymethanol are some of the simplest molecules that can form from this type of chemistry, and serve as tracers of ice mantle liberation in star-forming regions. These molecules also participate in gas-phase reactions that lead to amino acids and sugars, and as such are fundamentally important prebiotic molecules in interstellar environments. These types of small organic molecules also have high spectral line density, and are major contributors to line confusion in observational spectral surveys such as those conducted by Herschel and SOFIA. Therefore, the proposed research will aid in full data interpretation from Herschel and SOFIA observations. Currently there is no spectral information available for these molecules to guide observational studies, despite their importance in astrochemistry. This is because these molecules are difficult to study in laboratory settings due to their instability and reactivity. We are using highly exothermic O(1D) insertion reactions to produce these molecules in a supersonic expansion, and investigating the products using THz spectroscopy. This work builds on the work involved in our previous APRA award (Grant NNX11AI07G) "New THz Tools to Support Herschel Observations: Integrative Studies in Laboratory Spectroscopy, Observational Astronomy, and Chemical Modeling". In this previous award, we laid the groundwork for these experiments by constructing and benchmarking the spectrometer, designing and testing the molecular source used for the O(1D) reactions, and studying the proposed formation reactions for the laboratory work through computational studies. We have confirmed production of methanol from O(1D) insertion into methane, and then applied this chemistry to produce vinyl alcohol from ethylene. We have now also obtained preliminary spectra of aminomethanol. Here we propose to extend this work by finishing the aminomethanol characterization as well as examining methanediol and methoxymethanol during the next proposal period.

Importance of prebiotics in aquaculture as immunostimulants. Effects on immune system of Sparus aurata and Dicentrarchus labrax.

PubMed

Carbone, Donatella; Faggio, Caterina

2016-07-01

Infectious diseases in fish represent a major problem for the aquaculture field as they produce extensive damages and loss. Over the last few years, with increased development of the aquaculture industry, different methods have been used to contrast these pathologies. Common interest has led to the use of components (as additives in diets) that could contrast diseases without causing any negative impact on the environment. These components are represented by prebiotics, probiotics, and plant extracts. In this review, the effects of prebiotics are described. Prebiotics are indigestible fibres fermented by gut enzymes and commensal bacteria, whose beneficial effects are due to the by-products generated from fermentation. The influence of pre-biotics on the immune system of fish is called immunosaccharides. Mannanoligosaccharides (MOS), Fructooligosaccharides (FOS) and Inulin act at different levels in the innate immune response. For example, through phagocytosis, lysozyme activity, and the complement system activity, an increase in fish growth and an amelioration of their health status is brought about. In this review, the use of prebiotics in aquaculture, such as immunostimulants, has been highlighted: particularly in two teleost fish species, Sparus aurata and Dicentrarchus labrax. The results demonstrate that the road is still long and further studies are required, but the use of prebiotics, individually or coupled together, can open the doors to pioneering a new model of alternative components to antimicrobial agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Insight into the prebiotic concept: lessons from an exploratory, double blind intervention study with inulin-type fructans in obese women.

PubMed

Dewulf, Evelyne M; Cani, Patrice D; Claus, Sandrine P; Fuentes, Susana; Puylaert, Philippe G B; Neyrinck, Audrey M; Bindels, Laure B; de Vos, Willem M; Gibson, Glenn R; Thissen, Jean-Paul; Delzenne, Nathalie M

2013-08-01

To highlight the contribution of the gut microbiota to the modulation of host metabolism by dietary inulin-type fructans (ITF prebiotics) in obese women. A double blind, placebo controlled, intervention study was performed with 30 obese women treated with ITF prebiotics (inulin/oligofructose 50/50 mix; n=15) or placebo (maltodextrin; n=15) for 3 months (16 g/day). Blood, faeces and urine sampling, oral glucose tolerance test, homeostasis model assessment and impedancemetry were performed before and after treatment. The gut microbial composition in faeces was analysed by phylogenetic microarray and qPCR analysis of 16S rDNA. Plasma and urine metabolic profiles were analysed by 1H-NMR spectroscopy. Treatment with ITF prebiotics, but not the placebo, led to an increase in Bifidobacterium and Faecalibacterium prausnitzii; both bacteria negatively correlated with serum lipopolysaccharide levels. ITF prebiotics also decreased Bacteroides intestinalis, Bacteroides vulgatus and Propionibacterium, an effect associated with a slight decrease in fat mass and with plasma lactate and phosphatidylcholine levels. No clear treatment clustering could be detected for gut microbial analysis or plasma and urine metabolomic profile analyses. However, ITF prebiotics led to subtle changes in the gut microbiota that may importantly impact on several key metabolites implicated in obesity and/or diabetes. ITF prebiotics selectively changed the gut microbiota composition in obese women, leading to modest changes in host metabolism, as suggested by the correlation between some bacterial species and metabolic endotoxaemia or metabolomic signatures.

The use of prebiotics during the first year of life for atopy prevention and treatment

PubMed Central

de Moura, Priscilla Negrão; Rosário Filho, Nelson Augusto

2013-01-01

The incidence of allergic diseases has increased in recent decades. Therefore, the aim of this systematic review was to assess the efficacy of prebiotics for the prevention and treatment of allergic manifestations in children. We sought to conduct a systematic review of the effectiveness of prebiotics in the prevention and treatment of allergic diseases in children. We searched the MEDLINE, EMBASE, Cochrane Library, LILACS, SciELO, IBECS, Web of Science and Clinical Trials databases as well as Google Scholar and the references of the articles identified. Randomised clinical trials, in which one of the treatments was performed with prebiotics and the control group was treated with placebo, were included in the review. The data selection were performed by two reviewers, and the study quality was evaluated according to the Consolidated Standards of Reporting Trials (CONSORT) items, according to the recommendations for improving the quality of reports of randomised clinical trials. The selected studies showed heterogeneity with regard to the participants, albeit with similar outcomes. The treatment group size ranged from 134 to 259 children, and the studies compared prebiotic to placebo treatment in each group. In general, these articles showed a trend toward less allergic reactions in the groups receiving active therapy with prebiotics. Although there was a trend for reduced allergic symptoms following the administration of prebiotics, there was not sufficient evidence to establish that such treatment is effective for the prevention of allergies in children. PMID:25400918

Molecular self-assembly on surfaces

NASA Astrophysics Data System (ADS)

Mateo-Marti, E.; Pradier, C. M.

2012-09-01

The aim of the present research is to study the interaction of biomolecules, among them single amino acids, on metallic and mineral surfaces, and their chemical reactivity by means of powerful surface science techniques. Therefore, the use of simple biomolecules gives fundamental and significant information, including an adequate control of biomolecule-surface interactions, which will be unattainable to develop with more complex molecules. Furthermore, these studies are focussed on the catalytic properties of different surfaces that could be involved in molecular self-organization processes and the formation of prebiotic organic compounds.

Hydrogen cyanide polymers: from laboratory to space

NASA Astrophysics Data System (ADS)

Matthews, Clifford N.

1995-02-01

Hydrogen cyanide polymers - heterogeneous solids ranging in color from yellow to orange to red to black - may be among the organic macromolecules most readily formed within the solar system The non-volatile black crust of comet Halley for example, may consist largely of such polymers. It seems likely. too, that HCN polymers are a major constituent of the dark. CN bearing solids identified tentatively by IR spectra in the dust of some other comets. HCN polymerization could also account for some of the yellow-orange-red coloration of Jupiter and Saturn, and perhaps for the orange haze high in Titan's atmosphere. Studies of these polymers show that a yellow-brown powder can be extracted by water and further hydrolyzed to vield α-amino acids. Several instrumental methods used for the separation and identification of these intriguing materials. including pyrolysis mass spectrometry, Fourier transform IR photoacoustic spectroscopy and supercritical fluid extraction chromatography, reveal fragmentation patterns and chemical functionalities consistent with the presence of polymeric peptide precursors - polyamidines - in HCN polymers. Implications for prebiotic chemistry are profound. Primitive Earth may have been covered by HCN polymers and other organic products through bolide bombardment or terrestrial synthesis, producing a proteinaceous matrix able to bring about the molecular interactions leading to the emergence or life. Cyanide polymerization could also he a preferred pathway beyond Earth and the solar system, on planetary bodies and satellites around other stars and in the dusty molecular clouds of spiral galaxies.

Interaction of Metal Oxides with Biomolecules: Implication in Astrobiology

NASA Astrophysics Data System (ADS)

Kamaluddin; Iqubal, Md. Asif

2014-08-01

Steps of chemical evolution have been designated as formation of biomonomers followed by their polymerization and then to modify in an organized structure leading to the formation of first living cell. Polymerization of biomonomers could have required some catalyst. In addition to clay, role of metal ions and metal complexes as prebiotic catalyst in the synthesis and polymerization of biomonomers cannot be ruled out. Metal oxides are important constituents of Earth crust and that of other planets. These oxides might have adsorbed organic molecules and catalyzed the condensation processes, which may have led to the formation of first living cell. Different studies were performed in order to investigate the role of metal oxides (especially oxides of iron and manganese) in chemical evolution. Iron oxides (goethite, akaganeite and hematite) as well as manganese oxides (MnO, Mn2O3, Mn3O4 and MnO2) were synthesized and their characterization was done using IR, powder XRD, FE-SEM and TEM. Role of above oxides was studied in the adsorption of ribose nucleotides, formation of nucleobases from formamide and oligomerization of amino acids. Above oxides of iron and manganese were found to have good adsorption affinity towards ribose nucleotides, high catalytic activity in the formation of several nucleobases from formamide and oligomerization of glycine and alanine. Characterization of products was performed using UV, IR, HPLC and ESI-MS techniques. Presence of hematite-water system on Mars has been suggested to be a positive indicator in the chemical evolution on Mars.

Amino Acids from a Comet

NASA Technical Reports Server (NTRS)

Cook, Jamie Elisla

2009-01-01

NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

Prebiotic chemistry in clouds

NASA Technical Reports Server (NTRS)

Oberbeck, Verne R.; Marshall, John; Shen, Thomas

1991-01-01

The chemical evolution hypothesis of Woese (1979), according to which prebiotic reactions occurred rapidly in droplets in giant atmospheric reflux columns was criticized by Scherer (1985). This paper proposes a mechanism for prebiotic chemistry in clouds that answers Scherer's concerns and supports Woese's hypothesis. According to this mechanism, rapid prebiotic chemical evolution was facilitated on the primordial earth by cycles of condensation and evaporation of cloud drops containing clay condensation nuclei and nonvolatile monomers. For example, amino acids supplied by, or synthesized during entry of meteorites, comets, and interplanetary dust, would have been scavenged by cloud drops containing clay condensation nuclei and would be polymerized within cloud systems during cycles of condensation, freezing, melting, and evaporation of cloud drops.

Methods of preventing bacterial sepsis and wound complications after liver transplantation.

PubMed

Gurusamy, Kurinchi Selvan; Nagendran, Myura; Davidson, Brian R

2014-03-05

Bacterial sepsis and wound complications after liver transplantation increase mortality, morbidity, or hospital stay and are likely to increase overall transplant costs. All liver transplantation patients receive antibiotic prophylaxis. This is an update of our 2008 Cochrane systematic review on the same topic in which we identified seven randomised clinical trials. To assess the benefits and harms of different methods aimed at preventing bacterial sepsis and wound complications in people undergoing liver transplantation. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded to February 2013. We included only randomised clinical trials irrespective of language or publication status. We excluded quasi-randomised and other observational studies for assessment of benefits, but not for harms. Two review authors collected the data independently. We calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) using fixed-effect and the random-effects models based on available-case analysis. We identified only seven trials for inclusion, including 614 participants. Only one trial was of low risk of bias risk. Overall, the quality of evidence was very low. There were five comparisons in the seven trials: selective bowel decontamination versus inactive control; selective bowel decontamination versus prebiotics with probiotics; selective bowel decontamination versus prebiotics; prebiotics with probiotics versus prebiotics; and granulocyte-colony stimulating factor (G-CSF) versus control. Four trials compared selective bowel decontamination versus placebo or no treatment. In one trial, participants were randomised to selective bowel decontamination, active lactobacillus with fibres (probiotic with prebiotic), or to inactivated lactobacillus with fibres (prebiotic). In one trial, active lactobacillus with fibres (probiotic with prebiotic) was compared with inactive lactobacillus with fibres (prebiotic). In the remaining trial, different doses of G-CSF and placebo were compared. There was no trial comparing different antibiotic prophylactic regimens in people undergoing liver transplantation. Most trials included adults undergoing elective liver transplantation. There was no significant difference in proportion of people who died or required retransplantation between the intervention and control groups in any of the five comparison groups. MORTALITY There were no differences between 190 participants (three trials); 5/87 (adjusted proportion: 6.2%) in selective bowel decontamination group versus 7/103 (6.8%) in inactive control group; RR 0.91 (95% CI 0.31 to 2.72); 63 participants (one trial); 0/32 (0%) in selective bowel decontamination group versus 0/31 (0%) in prebiotics with probiotics group; RR - not estimable; 64 participants (one trial); 0/32 (0%) in selective bowel decontamination group versus 0/32 (0%) in prebiotics group; RR - not estimable; 129 participants (two trials); 0/64 (0%) in prebiotics with probiotics group versus 0/65 (0%) in prebiotics group; RR - not estimable; and 194 participants (one trial); 22/124 (17.7%) in G-CSF group versus 10/70 (14.3%) in placebo group; RR 1.24 (95% 0.62 to 2.47). RETRANSPLANTATION There were no differences between 132 participants (two trials); 4/58 (adjusted proportion: 6.9%) in selective bowel decontamination group versus 6/74 (8.1%) in inactive control group; RR 0.85 (95% CI 0.26 to 2.85); 63 participants (one trial); 1/32 (3.1%) in selective bowel decontamination group versus 0/31 (0%) in prebiotics with probiotics group; RR 2.91 (0.12 to 68.81); 64 participants (one trial); 1/32 (3.1%) in selective bowel decontamination group versus 0/32 (0%) in prebiotics group; RR 3.00 (95% CI 0.13 to 71.00); 129 participants (two trials); 0/64 (0%) in prebiotics with probiotics group versus 1/65 (1.5%) in prebiotics group; RR 0.33 (95% CI 0.01 to 7.9); and 194 participants (one trial); 10/124 (7.1%) in G-CSF group versus 5/70 (7.1%) in placebo group; RR 1.13 (95% CI 0.4 to 3.17).There was no significant difference in the graft rejections, intensive therapy unit stay, or hospital stay between the intervention and control groups in any of the comparisons. Overall, 193/611 participants (31.6%) developed infective complications. The proportion of people who developed infective complications and the number of infective complication episodes were significantly higher in the selective bowel decontamination group than in the prebiotics with probiotics group (1 study; 63 participants; 15/32 (46.9%) in selective bowel decontamination group versus 4/31 (12.9%) in prebiotics with probiotics group; RR 3.63; 95% CI 1.36 to 9.74 and 23/32 participants (0.72 infective complications per participant) in selective bowel decontamination group versus 4/31 participants (0.13 infective complications per participant) in prebiotics with probiotics group; rate ratio 5.58; 95% CI 1.94 to 16.09). There was no significant difference between the proportion of participants who developed infection and the number of infection episodes between the intervention group and control group in any of the other comparisons.No trials reported quality of life and overall serious adverse events. Currently, there is no clear evidence for any intervention offering significant benefits in the reduction of bacterial infections and wound complications in liver transplantation. Selective bowel decontamination may even increase the rate of infections compared with prebiotics with probiotics. The confidence intervals were wide and further randomised clinical trials of low risk of bias are necessary.

Template switching between PNA and RNA oligonucleotides

NASA Technical Reports Server (NTRS)

Bohler, C.; Nielsen, P. E.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

1995-01-01

The origin of the RNA world is not easily understood, as effective prebiotic syntheses of the components of RNA, the beta-ribofuranoside-5'-phosphates, are hard to envisage. Recognition of this difficulty has led to the proposal that other genetic systems, the components of which are more easily formed, may have preceded RNA. This raises the question of how transitions between one genetic system and another could occur. Peptide nucleic acid (PNA) resembles RNA in its ability to form double-helical complexes stabilized by Watson-Crick hydrogen bonding between adenine and thymine and between cytosine and guanine, but has a backbone that is held together by amide rather than by phosphodiester bonds. Oligonucleotides bases on RNA are known to act as templates that catalyse the non-enzymatic synthesis of their complements from activated mononucleotides, we now show that RNA oligonucleotides facilitate the synthesis of complementary PNA strands and vice versa. This suggests that a transition between different genetic systems can occur without loss of information.

Clay catalyzed RNA synthesis under Martian conditions: Application for Mars return samples.

PubMed

Joshi, Prakash C; Dubey, Krishna; Aldersley, Michael F; Sausville, Meaghen

2015-06-26

Catalysis by montmorillonites clay minerals is regarded as a feasible mechanism for the abiotic production and polymerization of key biomolecules on early Earth. We have investigated a montmorillonite-catalyzed reaction of the 5'-phosphorimidazolide of nucleosides as a model to probe prebiotic synthesis of RNA-type oligomers. Here we show that this model is specific for the generation of RNA oligomers despite deoxy-mononucleotides adsorbing equally well onto the montmorillonite catalytic surfaces. Optimum catalytic activity was observed over a range of pH (6-9) and salinity (1 ± 0.2 M NaCl). When the weathering steps of early Earth that generated catalytic montmorillonite were modified to meet Martian soil conditions, the catalytic activity remained intact without altering the surface layer charge. Additionally, the formation of oligomers up to tetramer was detected using as little as 0.1 mg of Na⁺-montmorillonite, suggesting that the catalytic activity of a Martian clay return sample can be investigated with sub-milligram scale samples. Copyright © 2015 Elsevier Inc. All rights reserved.

Valorization of Cheese and Tofu Whey through Enzymatic Synthesis of Lactosucrose

PubMed Central

Corzo-Martinez, Marta; Luscher, Alice; de las Rivas, Blanca; Muñoz, Rosario; Moreno, F. Javier

2015-01-01

This work deals with the development of a new bioprocess for the efficient synthesis of lactosucrose, a potential prebiotic oligosaccharide with a high value-added, from two important and inexpensive agro-industrial by-products such as tofu whey and cheese whey permeate. The bioconversion is driven by the ability of the enzyme levansucrase SacB from Bacillus subtilis CECT 39 to transfructosylate lactose contained in the cheese whey permeate by using not only sucrose but also raffinose and stachyose, which are present in considerable amounts in the tofu whey, as suitable donors of fructosyl moieties. The maximum lactosucrose concentration obtained from both by-products was 80.1 g L-1 after a short reaction time 120 min at 37°C, leading to productivity and specific productivity values of 40.1 g lactosucrose L-1 h-1 and 80.1 mg lactosucrose U enzyme−1 h−1, respectively. Findings contained in this work could provide a new strategy to valorize agro-industrial by-products as cheese whey permeate and, specially, tofu whey by means of their use as renewable resources in the enzymatic synthesis of bioactive oligosaccharides. PMID:26406885

Gluco-oligosaccharides synthesized by glucosyltransferases from constitutive mutants of Leuconostoc mesenteroides strain Lm 28.

PubMed

Iliev, I; Vassileva, T; Ignatova, C; Ivanova, I; Haertlé, T; Monsan, P; Chobert, J-M

2008-01-01

To find different types of glucosyltransferases (GTFs) produced by Leuconostoc mesenteroides strain Lm 28 and its mutant forms, and to check the effectiveness of gluco-oligosaccharide synthesis using maltose as the acceptor. Constitutive mutants were obtained after chemical mutagenesis by ethyl methane sulfonate. Lm M281 produced more active GTFs than that obtained by the parental strain cultivated on sucrose. GTF from Lm M286 produced a resistant glucan, based on endo-dextranase and amyloglucosidase hydrolysis. The extracellular enzymes from Lm M286 catalyse acceptor reactions and transfer the glucose unit from sucrose to maltose to produce gluco-oligosaccharides (GOS). By increasing the sucrose/maltose ratio, it was possible to catalyse the synthesis of oligosaccharides of increasing degree of polymerization (DP). Different types of GTFs (dextransucrase, alternansucrase and levansucrase) were produced from new constitutive mutants of Leuc. mesenteroides. GTFs from Lm M286 can catalyse the acceptor reaction in the presence of maltose, leading to the synthesis of branched oligosaccharides. Conditions were optimized to synthesize GOS by using GTFs from Lm M286, with the aim of producing maximum quantities of branched-chain oligosaccharides with DP 3-5. This would allow the use of the latter as prebiotics.

Optimization of Oligosaccharide Synthesis from Cellobiose by Dextransucrase

NASA Astrophysics Data System (ADS)

Kim, Misook; Day, Donal F.

There is a growing market for oligosaccharides as sweeteners, prebiotics, anticariogenic compounds, and immunostimulating agents in both food and pharmaceutical industries. Interest in novel carbohydrate-based products has grown because of their reduced toxicity and low immune response. Cellobiose is potentially valuable as a nondigestible sugar. The reaction of cellobiose, as an acceptor with a sucrose as a donor, catalyzed by a dextransucrase from Leuconostoc mesenteroides B-512FMCM, produced a series of cellobio-oligosaccharides. This production system was optimized using a Box-Behnken experimental design for 289 mM of sucrose and 250 mM of cellobiose and 54 U of the enzyme at pH 5.2 and 30 °C, to produce maximum yields of oligosaccharide.

Use of prebiotic carbohydrate as wall material on lime essential oil microparticles.

PubMed

Campelo, Pedro Henrique; Figueiredo, Jayne de Abreu; Domingues, Rosana Zacarias; Fernandes, Regiane Victória de Barros; Botrel, Diego Alvarenga; Borges, Soraia Vilela

2017-09-01

The aim of this work was to study the use of different prebiotic biopolymers in lime essential oil microencapsulation. Whey protein isolate, inulin and oligofructose biopolymers were used. The addition of prebiotic biopolymers reduced emulsion viscosity, although it produced larger droplet sizes (0.31-0.32 µm). Moisture values (2.94-3.13 g/100 g dry solids) and water activity (0.152-0.185) were satisfactory, being within the appropriate range for powdered food quality. Total oil content, limonene retention values and antioxidant activity of the microparticles containing essential oil decreased in the presence of the carbohydrates. The addition of prebiotic biopolymers reduced the microparticle thermal stability. X-ray diffraction confirmed the amorphous characteristic of the microparticles and the interaction of the essential oil with the wall material. The presence of prebiotic biopolymers can be a good alternative for lime essential oil microparticles, mainly using fibre that has a functional food appeal and can improve consumer health.

In vitro evaluation of the fermentation properties and potential prebiotic activity of Agave fructans.

PubMed

Gomez, E; Tuohy, K M; Gibson, G R; Klinder, A; Costabile, A

2010-06-01

This study was carried out to evaluate in vitro the fermentation properties and the potential prebiotic activity of Agave-fructans extracted from Agave tequilana (Predilife). Five different commercial prebiotics were compared using 24-h pH-controlled anaerobic batch cultures inoculated with human faecal slurries. Measurement of prebiotic efficacy was obtained by comparing bacterial changes, and the production of short-chain fatty acids (SCFA) was also determined. Effects upon major groups of the microbiota were monitored over 24 h incubations by fluorescence in situ hybridization. SCFA were measured by HPLC. Fermentation of the Agave fructans (Predilife) resulted in a large increase in numbers of bifidobacteria and lactobacilli. Under the in vitro conditions used, this study has shown the differential impact of Predilife on the microbial ecology of the human gut. This is the first study reporting of a potential prebiotic mode of activity for Agave fructans investigated which significantly increased populations of bifidobacteria and lactobacilli compared to cellulose used as a control.

Probiotics and prebiotics: prospects for public health and nutritional recommendations.

PubMed

Sanders, Mary Ellen; Lenoir-Wijnkoop, Irene; Salminen, Seppo; Merenstein, Daniel J; Gibson, Glenn R; Petschow, Bryon W; Nieuwdorp, Max; Tancredi, Daniel J; Cifelli, Christopher J; Jacques, Paul; Pot, Bruno

2014-02-01

Probiotics and prebiotics are useful interventions for improving human health through direct or indirect effects on the colonizing microbiota. However, translation of these research findings into nutritional recommendations and public health policy endorsements has not been achieved in a manner consistent with the strength of the evidence. More progress has been made with clinical recommendations. Conclusions include that beneficial cultures, including probiotics and live cultures in fermented foods, can contribute towards the health of the general population; prebiotics, in part due to their function as a special type of soluble fiber, can contribute to the health of the general population; and a number of challenges must be addressed in order to fully realize probiotic and prebiotic benefits, including the need for greater awareness of the accumulated evidence on probiotics and prebiotics among policy makers, strategies to cope with regulatory roadblocks to research, and high-quality human trials that address outstanding research questions in the field. © 2014 New York Academy of Sciences.

Probiotics, prebiotics and colorectal cancer prevention.

PubMed

Ambalam, Padma; Raman, Maya; Purama, Ravi Kiran; Doble, Mukesh

2016-02-01

Colorectal cancer (CRC), the third major cause of mortality among various cancer types in United States, has been increasing in developing countries due to varying diet and dietary habits and occupational hazards. Recent evidences showed that composition of gut microbiota could be associated with the development of CRC and other gut dysbiosis. Modulation of gut microbiota by probiotics and prebiotics, either alone or in combination could positively influence the cross-talk between immune system and microbiota, would be beneficial in preventing inflammation and CRC. In this review, role of probiotics and prebiotics in the prevention of CRC has been discussed. Various epidemiological and experimental studies, specifically gut microbiome research has effectively improved the understanding about the role of probiotics and microbial treatment as anticarcinogenic agents. A few human studies support the beneficial effect of probiotics and prebiotics; hence, comprehensive understanding is urgent to realize the clinical applications of probiotics and prebiotics in CRC prevention. Copyright © 2016 Elsevier Ltd. All rights reserved.

Induction of regulatory T cells: A role for probiotics and prebiotics to suppress autoimmunity.

PubMed

Dwivedi, Mitesh; Kumar, Prasant; Laddha, Naresh C; Kemp, E Helen

2016-04-01

Regulatory T cells (Tregs) are comprised of a heterogeneous population of cells that play a vital role in suppressing inflammation and maintaining immune tolerance. Given the crucial role of Tregs in maintaining immune homeostasis, it is probably not surprising that many microbial species and their metabolites have the potential to induce Tregs. There is now great interest in the therapeutic potential of probiotics and prebiotics based strategies for a range of autoimmune disorders. This review will summarise recent findings concerning the role of probiotics and prebiotics in induction of Tregs to ameliorate the autoimmune conditions. In addition, the article is focused to explain the different mechanisms of Treg induction and function by these probiotics and prebiotics, based on the available studies till date. The article further proposes that induction of Tregs by probiotics and prebiotics could lead to the development of new therapeutic approach towards curbing the autoimmune response and as an alternative to detrimental immunosuppressive drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantification of prebiotics in commercial infant formulas.

PubMed

Sabater, Carlos; Prodanov, Marin; Olano, Agustín; Corzo, Nieves; Montilla, Antonia

2016-03-01

Since breastfeeding is not always possible, infant formulas (IFs) are supplemented with prebiotic oligosaccharides, such as galactooligosaccharides (GOS) and/or fructooligosaccharides (FOS) to exert similar effects to those of the breast milk. Nowadays, a great number of infant formulas enriched with prebiotics are disposal in the market, however there are scarce data about their composition. In this study, the combined use of two chromatographic methods (GC-FID and HPLC-RID) for the quantification of carbohydrates present in commercial infant formulas have been used. According to the results obtained by GC-FID for products containing prebiotics, the content of FOS, GOS and GOS/FOS was in the ranges of 1.6-5.0, 1.7-3.2, and 0.08-0.25/2.3-3.8g/100g of product, respectively. HPLC-RID analysis allowed quantification of maltodextrins with degree of polymerization (DP) up to 19. The methodology proposed here may be used for routine quality control of infant formula and other food ingredients containing prebiotics. Copyright © 2015 Elsevier Ltd. All rights reserved.

A food additive with prebiotic properties of an α-d-glucan from lactobacillus plantarum DM5.

PubMed

Das, Deeplina; Baruah, Rwivoo; Goyal, Arun

2014-08-01

An α-d-glucan produced by Lactobacillus plantarum DM5 was explored for in vitro prebiotic activities. Glucan-DM5 demonstrated 21.6% solubility, 316.9% water holding capacity, 86.2% flocculation activity, 71.4% emulsification activity and a degradation temperature (Td) of 292.2°C. Glucan-DM5 exhibited lowest digestibility of 0.54% by artificial gastric juice, 0.21% by intestinal fluid and 0.32% by α-amylase whereas the standard prebiotic inulin, showed 25.23%, 5.97% and 19.13%, hydrolysis, respectively. Prebiotic activity assay of glucan-DM5 displayed increased growth of probiotic bacteria such as Bifidobacterium infantis and Lactobacillus acidophilus, but did not support the growth of non-probiotic bacteria such as Escherichia coli and Enterobacter aerogenes. The overall findings indicated that glucan from L. plantarum DM5 can serve as a potential prebiotic additive for food products. Copyright © 2014 Elsevier B.V. All rights reserved.

Formation of Amino Acids and Nucleotide Bases in a Titan Atmosphere Simulation Experiment

PubMed Central

Yelle, R.V.; Buch, A.; Carrasco, N.; Cernogora, G.; Dutuit, O.; Quirico, E.; Sciamma-O'Brien, E.; Smith, M.A.; Somogyi, Á.; Szopa, C.; Thissen, R.; Vuitton, V.

2012-01-01

Abstract The discovery of large (>100 u) molecules in Titan's upper atmosphere has heightened astrobiological interest in this unique satellite. In particular, complex organic aerosols produced in atmospheres containing C, N, O, and H, like that of Titan, could be a source of prebiotic molecules. In this work, aerosols produced in a Titan atmosphere simulation experiment with enhanced CO (N2/CH4/CO gas mixtures of 96.2%/2.0%/1.8% and 93.2%/5.0%/1.8%) were found to contain 18 molecules with molecular formulae that correspond to biological amino acids and nucleotide bases. Very high-resolution mass spectrometry of isotopically labeled samples confirmed that C4H5N3O, C4H4N2O2, C5H6N2O2, C5H5N5, and C6H9N3O2 are produced by chemistry in the simulation chamber. Gas chromatography–mass spectrometry (GC-MS) analyses of the non-isotopic samples confirmed the presence of cytosine (C4H5N3O), uracil (C5H4N2O2), thymine (C5H6N2O2), guanine (C5H5N5O), glycine (C2H5NO2), and alanine (C3H7NO2). Adenine (C5H5N5) was detected by GC-MS in isotopically labeled samples. The remaining prebiotic molecules were detected in unlabeled samples only and may have been affected by contamination in the chamber. These results demonstrate that prebiotic molecules can be formed by the high-energy chemistry similar to that which occurs in planetary upper atmospheres and therefore identifies a new source of prebiotic material, potentially increasing the range of planets where life could begin. Key Words: Astrochemistry—Planetary atmospheres—Titan—Astrobiology. Astrobiology 12, 809–817. PMID:22917035

The Influence of Prebiotics on Neurobiology and Behavior.

PubMed

Kao, A C C; Harty, S; Burnet, P W J

2016-01-01

Manipulating the intestinal microbiota for the benefit of the brain is a concept that has become widely acknowledged. Prebiotics are nondigestible nutrients (i.e., fibers, carbohydrates, or various saccharides) that proliferate intrinsic, beneficial gut bacteria, and so provide an alternative strategy for effectively altering the enteric ecosystem, and thence brain function. Rodent studies demonstrating neurobiological changes following prebiotic intake are slowly emerging, and have thus far revealed significant benefits in disease models, including antiinflammatory and neuroprotective actions. There are also compelling data showing the robust and favorable effects of prebiotics on several behavioral paradigms including, anxiety, learning, and memory. At present, studies in humans are limited, though there is strong evidence for prebiotics modulating emotional processes and the neuroendocrine stress response that may underlie the pathophysiology of anxiety. While the mechanistic details linking the enteric microbiota to the central nervous system remain to be elucidated, there are a number of considerations that can guide future studies. These include the modulation of intestinal endocrine systems and inflammatory cascades, as well as direct interaction with the enteric nervous system and gut mucosa. Our knowledge of gut microbiome-brain communication is steadily progressing, and thorough investigations validating the use of prebiotics in the treatment of neuropsychiatric disorders would be highly valued and are encouraged. © 2016 Elsevier Inc. All rights reserved.

Positive interaction between prebiotics and thiazolidinedione treatment on adiposity in diet-induced obese mice.

PubMed

Alligier, Maud; Dewulf, Evelyne M; Salazar, Nuria; Mairal, Aline; Neyrinck, Audrey M; Cani, Patrice D; Langin, Dominique; Delzenne, Nathalie M

2014-07-01

To investigate whether inulin-type fructan (ITF) prebiotics could counteract the thiazolidinedione (TZD, PPARγ activator) induced-fat mass gain, without affecting its beneficial effect on glucose homeostasis, in high-fat (HF) diet fed mice. Male C57bl6/J mice were fed a HF diet alone or supplemented with ITF prebiotics (0.2 g/day × mouse) or TZD (30 mg pioglitazone (PIO)/kg body weight × day) or both during 4 weeks. An insulin tolerance test was performed after 3 weeks of treatment. As expected, PIO improved glucose homeostasis and increased adiponectinaemia. Furthermore, it induced an over-expression of several PPARγ target genes in white adipose tissues. ITF prebiotics modulated the PIO-induced PPARγ activation in a tissue-dependent manner. The co-treatment with ITF prebiotics and PIO maintained the beneficial impact of TZD on glucose homeostasis and adiponectinaemia. Moreover, the combination of both treatments reduced fat mass accumulation, circulating lipids and hepatic triglyceride content, suggesting an overall improvement of metabolism. Finally, the co-treatment favored induction of white-to-brown fat conversion in subcutaneous adipose tissue, thereby leading to the development of brite adipocytes that could increase the oxidative capacity of the tissue. ITF prebiotics decrease adiposity and improve the metabolic response in HF fed mice treated with TZD. © 2014 The Obesity Society.

Scientific evidence for health effects attributed to the consumption of probiotics and prebiotics: an update for current perspectives and future challenges.

PubMed

Martinez, Rafael Chacon Ruiz; Bedani, Raquel; Saad, Susana Marta Isay

2015-12-28

Probiotics and prebiotics, mainly commercialised as food ingredients and also as supplements, are considered highly profitable niche markets. However, in recent years, the food industry has suffered from a series of health claim restrictions on probiotics and prebiotics in many parts of the world, including those made by the European Food Safety Authority. Therefore, we reviewed the core benefits of probiotic and prebiotic consumption on health. A number of studies have examined the prevention and/or management of intestinal infections, respiratory tract infections, CVD, osteoporosis, urogenital infections, cavities, periodontal disease and halitosis, allergic reactions, inflammatory bowel disease and irritable bowel syndrome and Helicobacter pylori gastric infections. In fact, a deeper understanding of the mechanisms involved in human microbiota and immune system modulation by probiotics and prebiotics relies on continuous efforts to establish suitable biomarkers of health and diseases risk factors for the design of clinical trials required for health claim approval. In spite of the promising results, the performance of large, long-term, well-planned, well-aligned clinical studies is crucial to provide more reliability and a more solid basis for the outcomes achieved and to support the potential use of probiotics and prebiotics in clinical practice.

Targeting the Microbiota, from Irritable Bowel Syndrome to Mood Disorders: Focus on Probiotics and Prebiotics.

PubMed

Pusceddu, M M; Murray, K; Gareau, M G

2018-03-01

The crosstalk between the gut and the brain has revealed a complex communication system responsible for maintaining a proper gastrointestinal homeostasis as well as affect emotional mood and cognitive functions. Recent research has revealed that beneficial manipulation of the microbiota by probiotics and prebiotics represent an emerging and novel strategy for the treatment of a large spectrum of diseases ranging from visceral pain to mood disorders. The review critically evaluates current knowledge of the effects exerted by both probiotics and prebiotics in irritable bowel syndrome (IBS) and mood disorders such as anxiety and depression. Relevant literature was identified through a search of MEDLINE via PubMed using the following words, "probiotics", "prebiotics", "microbiota", and "gut-brain axis" in combination with "stress", "depression", "IBS", and "anxiety". A number of trials have shown efficacy of probiotics and prebiotics in ameliorating both IBS related symptoms and emotional states. However, limitations have been found especially due to the small number of clinical studies, studies design, patient sample size, and placebo effect. Nonetheless, current finding supports the view that beneficial manipulation of the microbiota through both probiotics and prebiotics intake represents a novel attractive strategy to treat gut-brain axis disorders such as IBS and depression.

Quality and sensory acceptability of a chilled functional apple ready-dessert.

PubMed

Keenan, D F; Brunton, N P; Gormley, T R; Butler, F

2012-04-01

An apple and dairy based ready-dessert with an added prebiotic was stored and chill temperatures and number of quality attributes were monitored during chill (4 °C) storage for 30 days. All ready-desserts were thermally processed by sous vide (P (90) > 10 min). The stability of the dairy component in ready-desserts was monitored by measuring volatile free fatty acids. Changes in these components were more evident in prebiotic-enriched samples compared to controls. However, no significant differences were observed over storage in control and prebiotic-enriched ready-desserts. This was supported by sensory analysis that showed no significant changes over storage in control or prebiotic-enriched samples. Of the other quality parameters, the addition of prebiotic inclusions resulted in lower L and b values and dry matter (p < 0.05), while increasing (p < 0.05) soluble solids content compared to control samples. Fluctuations in some of the quality parameters were also observed over storage. Rheological characteristics, i.e. flow behaviour (n), consistency index (K), storage (G'), loss (G″) and complex (G*) moduli were unaffected by prebiotic inclusion. However, storage affected the rheological characteristics of ready-desserts. A decrease (p < 0.05) in flow behaviour (n) led to concomitant increases in consistency index (K) and complex modulus (G*) values in control samples.

Enhanced vaccination effect against influenza by prebiotics in elderly patients receiving enteral nutrition.

PubMed

Akatsu, Hiroyasu; Nagafuchi, Shinya; Kurihara, Rina; Okuda, Kenji; Kanesaka, Takeshi; Ogawa, Norihiro; Kanematsu, Takayoshi; Takasugi, Satoshi; Yamaji, Taketo; Takami, Masao; Yamamoto, Takayuki; Ohara, Hirotaka; Maruyama, Mitsuo

2016-02-01

We investigated the effect of prebiotics on the immunological response after influenza vaccination in enterally fed elderly individuals. The intervention group was given an enteral formula containing lactic acid bacteria-fermented milk products. In addition, two different types of other prebiotics, galacto-oligosaccharide and bifidogenic growth stimulator, were also given. The two prebiotics improved intestinal microbiota differently. In a control group, a standard formula without prebiotics was given. An enteral formula with (intervention group [F]) or without (control group [C]) prebiotics was given through percutaneous endoscopic gastrostomy to elderly participants for 10 weeks. Influenza vaccine was inoculated at week 4. Nutritional and biochemical indices, intestinal micro bacteria and immunological indices were analyzed. The Bifidobacterium count in groups F and C at week 0 was 6.4 ± 1.9 and 6.6 ± 3.0 (log10 [count/g feces]), respectively. Although the count in group C decreased at week 10, the count in group F increased. The Bacteroides count in group F increased from 10.7 ± 0.9 to 11.4 ± 0.5, but decreased in group C from 11.2 ± 0.2 to 10.7 ± 0.4. Although the enhanced titers of H1N1, H3N2 and B antigens against the vaccine decreased thereafter in group C, these enhanced titers in group F could be maintained. Our findings suggest that prebiotics affect the intestinal microbiota and might maintain the antibody titers in elderly individuals. © 2015 Japan Geriatrics Society.

Prebiotic supplementation improves appetite control in children with overweight and obesity: a randomized controlled trial.

PubMed

Hume, Megan P; Nicolucci, Alissa C; Reimer, Raylene A

2017-04-01

Background: Prebiotics have been shown to improve satiety in adults with overweight and obesity; however, studies in children are limited. Objective: We examined the effects of prebiotic supplementation on appetite control and energy intake in children with overweight and obesity. Design: This study was a randomized, double-blind, placebo-controlled trial. Forty-two boys and girls, ages 7-12 y, with a body mass index (BMI) of ≥85th percentile were randomly assigned to 8 g oligofructose-enriched inulin/d or placebo (maltodextrin) for 16 wk. Objective measures of appetite included energy intake at an ad libitum breakfast buffet, 3-d food records, and fasting satiety hormone concentrations. Subjective appetite ratings were obtained from visual analog scales before and after the breakfast. Children's Eating Behavior Questionnaires were also completed by caregivers. Results: Compared with placebo, prebiotic intake resulted in significantly higher feelings of fullness ( P = 0.04) and lower prospective food consumption ( P = 0.03) at the breakfast buffet at 16 wk compared with baseline. Compared with placebo, prebiotic supplementation significantly reduced energy intake at the week 16 breakfast buffet in 11- and 12-y-olds ( P = 0.04) but not in 7- to 10-y-olds. Fasting adiponectin ( P = 0.04) and ghrelin ( P = 0.03) increased at 16 wk with the prebiotic compared with placebo. In intent-to-treat analysis, there was a trend for prebiotic supplementation to reduce BMI z score to a greater extent than placebo (-3.4%; P = 0.09) and a significant -3.8% reduction in per-protocol analysis ( P = 0.043). Conclusions: Independent of other lifestyle changes, prebiotic supplementation in children with overweight and obesity improved subjective appetite ratings. This translated into reduced energy intake in a breakfast buffet in older but not in younger children. This simple dietary change has the potential to help with appetite regulation in children with obesity. This trial was registered at clinicaltrials.gov as NCT02125955. © 2017 American Society for Nutrition.

Prebiotic Supplementation has Only Minimal Effects on Growth Efficiency, Intestinal Health and Disease Resistance of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi Fed 30% Soybean Meal

PubMed Central

Sealey, Wendy M.; Conley, Zachariah B.; Bensley, Molly

2015-01-01

Prebiotics have successfully been used to prevent infectious diseases in aquaculture and there is an increasing amount of literature that suggests that these products can also improve alternative protein utilization and digestion. Therefore, the objective of this study was to examine whether prebiotic supplementation increased the growth efficiency, intestinal health, and disease resistance of cutthroat trout fed a high level of dietary soybean meal. To achieve this objective, juvenile Westslope cutthroat trout (Oncorhynchus clarkii lewisi) were fed a practical type formulation with 0 or 30% dietary soybean meal with or without the commercial prebiotic (Grobiotic-A) prior to experimental exposure to Flavobacterium psychrophilum. Juvenile Westslope cutthroat trout (initial weight 7.8 g/fish ±SD of 0.5 g) were stocked at 30 fish/tank in 75 L tanks with six replicate tanks per diet and fed their respective diets for 20 weeks. Final weights of Westslope cutthroat trout were affected by neither dietary soybean meal inclusion level (P = 0.9582) nor prebiotic inclusion (P = 0.9348) and no interaction was observed (P = 0.1242). Feed conversion ratios were similarly not affected by soybean meal level (P = 0.4895), prebiotic inclusion (P = 0.3258) or their interaction (P = 0.1478). Histological examination of the distal intestine of Westslope cutthroat trout demonstrated increases in inflammation due to both increased soybean meal inclusion level (P = 0.0038) and prebiotic inclusion (P = 0.0327) without significant interaction (P = 0.3370). Feeding dietary soybean meal level at 30% increased mortality of F. psychrophilum cohabitation challenged Westslope cutthroat trout (P = 0.0345) while prebiotic inclusion tended to decrease mortality (P = 0.0671). These results indicate that subclinical alterations in intestinal inflammation levels due to high dietary inclusion levels of soybean meal could predispose Westslope cutthroat trout to F. psychrophilum infection. PMID:26379662

Prebiotic Supplementation has Only Minimal Effects on Growth Efficiency, Intestinal Health and Disease Resistance of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi Fed 30% Soybean Meal.

PubMed

Sealey, Wendy M; Conley, Zachariah B; Bensley, Molly

2015-01-01

Prebiotics have successfully been used to prevent infectious diseases in aquaculture and there is an increasing amount of literature that suggests that these products can also improve alternative protein utilization and digestion. Therefore, the objective of this study was to examine whether prebiotic supplementation increased the growth efficiency, intestinal health, and disease resistance of cutthroat trout fed a high level of dietary soybean meal. To achieve this objective, juvenile Westslope cutthroat trout (Oncorhynchus clarkii lewisi) were fed a practical type formulation with 0 or 30% dietary soybean meal with or without the commercial prebiotic (Grobiotic-A) prior to experimental exposure to Flavobacterium psychrophilum. Juvenile Westslope cutthroat trout (initial weight 7.8 g/fish ±SD of 0.5 g) were stocked at 30 fish/tank in 75 L tanks with six replicate tanks per diet and fed their respective diets for 20 weeks. Final weights of Westslope cutthroat trout were affected by neither dietary soybean meal inclusion level (P = 0.9582) nor prebiotic inclusion (P = 0.9348) and no interaction was observed (P = 0.1242). Feed conversion ratios were similarly not affected by soybean meal level (P = 0.4895), prebiotic inclusion (P = 0.3258) or their interaction (P = 0.1478). Histological examination of the distal intestine of Westslope cutthroat trout demonstrated increases in inflammation due to both increased soybean meal inclusion level (P = 0.0038) and prebiotic inclusion (P = 0.0327) without significant interaction (P = 0.3370). Feeding dietary soybean meal level at 30% increased mortality of F. psychrophilum cohabitation challenged Westslope cutthroat trout (P = 0.0345) while prebiotic inclusion tended to decrease mortality (P = 0.0671). These results indicate that subclinical alterations in intestinal inflammation levels due to high dietary inclusion levels of soybean meal could predispose Westslope cutthroat trout to F. psychrophilum infection.

Localized aliphatic organic material on the surface of Ceres

NASA Astrophysics Data System (ADS)

De Sanctis, M. C.; Ammannito, E.; McSween, H. Y.; Raponi, A.; Marchi, S.; Capaccioni, F.; Capria, M. T.; Carrozzo, F. G.; Ciarniello, M.; Fonte, S.; Formisano, M.; Frigeri, A.; Giardino, M.; Longobardo, A.; Magni, G.; McFadden, L. A.; Palomba, E.; Pieters, C. M.; Tosi, F.; Zambon, F.; Raymond, C. A.; Russell, C. T.

2017-02-01

Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

Planetary Organic Chemistry and the Origins of Biomolecules

PubMed Central

Benner, Steven A.; Kim, Hyo-Joong; Kim, Myung-Jung; Ricardo, Alonso

2010-01-01

Organic chemistry on a planetary scale is likely to have transformed carbon dioxide and reduced carbon species delivered to an accreting Earth. According to various models for the origin of life on Earth, biological molecules that jump-started Darwinian evolution arose via this planetary chemistry. The grandest of these models assumes that ribonucleic acid (RNA) arose prebiotically, together with components for compartments that held it and a primitive metabolism that nourished it. Unfortunately, it has been challenging to identify possible prebiotic chemistry that might have created RNA. Organic molecules, given energy, have a well-known propensity to form multiple products, sometimes referred to collectively as “tar” or “tholin.” These mixtures appear to be unsuited to support Darwinian processes, and certainly have never been observed to spontaneously yield a homochiral genetic polymer. To date, proposed solutions to this challenge either involve too much direct human intervention to satisfy many in the community, or generate molecules that are unreactive “dead ends” under standard conditions of temperature and pressure. Carbohydrates, organic species having carbon, hydrogen, and oxygen atoms in a ratio of 1:2:1 and an aldehyde or ketone group, conspicuously embody this challenge. They are components of RNA and their reactivity can support both interesting spontaneous chemistry as part of a “carbohydrate world,” but they also easily form mixtures, polymers and tars. We describe here the latest thoughts on how on this challenge, focusing on how it might be resolved using minerals containing borate, silicate, and molybdate, inter alia. PMID:20504964

Assessing the effects of different prebiotic dietary oligosaccharides in sheep milk ice cream.

PubMed

Balthazar, C F; Silva, H L A; Vieira, A H; Neto, R P C; Cappato, L P; Coimbra, P T; Moraes, J; Andrade, M M; Calado, V M A; Granato, D; Freitas, M Q; Tavares, M I B; Raices, R S L; Silva, M C; Cruz, A G

2017-01-01

The objective of this study was to assess the effects of different prebiotic dietary oligosaccharides (inulin, fructo-oligosaccharide, galacto-oligossacaride, short-chain fructo-oligosaccharide, resistant starch, corn dietary oligosaccharide and polydextrose) in non-fat sheep milk ice cream processing through physical parameters, water mobility and thermal analysis. Overall, the fat replacement by dietary prebiotic oligosaccharides significantly decreased the melting time, melting temperature and the fraction and relaxation time for fat and bound water (T 22 ) while increased the white intensity and glass transition temperature. The replacement of sheep milk fat by prebiotics in sheep milk ice cream constitutes an interesting option to enhance nutritional aspects and develop a functional food. Copyright © 2016 Elsevier Ltd. All rights reserved.

Novel probiotics and prebiotics: road to the market.

PubMed

Kumar, Himanshu; Salminen, Seppo; Verhagen, Hans; Rowland, Ian; Heimbach, Jim; Bañares, Silvia; Young, Tony; Nomoto, Koji; Lalonde, Mélanie

2015-04-01

Novel probiotics and prebiotics designed to manipulate the gut microbiota for improving health outcomes are in demand as the importance of the gut microbiota in human health is revealed. The regulations governing introduction of novel probiotics and prebiotics vary by geographical region. Novel foods and foods with health claims fall under specific regulations in several countries. The paper reviews the main requirements of the regulations in the EU, USA, Canada and Japan. We propose a number of areas that need to be addressed in any safety assessment of novel probiotics and prebiotics. These include publication of the genomic sequence, antibiotic resistance profiling, selection of appropriate in vivo model, toxicological studies (including toxin production) and definition of target population. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of inulin in cheese as prebiotic, fat replacer and texturizer: a review.

PubMed

Karimi, Reza; Azizi, Mohammad Hossein; Ghasemlou, Mehran; Vaziri, Moharam

2015-03-30

Inulin is a food ingredient that belongs to a class of carbohydrates known as fructans. Nutritionally it has functional properties and health-promoting effects that include reduced calorie value, dietary fiber and prebiotic effects. Inulin is increasingly used in industrially processed dairy and non-dairy products because it is a bulking agent for use in fat replacement, textural modification and organoleptic improvement. Addition of inulin to different kinds of cheese can be beneficial in the manufacture of a reduced- or low-fat, texturized, symbiotic product. This paper gives an overview of some aspects of the microstructural, textural, rheological, prebiotic and sensorial effects of inulin incorporated in cheese as fat replacer, prebiotic and texture modifier. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enzyme and microbial technology for synthesis of bioactive oligosaccharides: an update.

PubMed

Chen, Rachel

2018-04-01

Oligosaccharides, in either free or bound forms, play crucial roles in a wide range of biological processes. Increasing appreciation of their roles in cellular communication, interaction, pathogenesis, and prebiotic functions has stimulated tremendous interests in their synthesis. Pure and structurally defined oligosaccharides are essential for fundamental studies. On the other hand, for those with near term medical and nutraceutical applications, their large-scale synthesis is necessary. Unfortunately, oligosaccharides are notoriously difficult in their synthesis, and their enormous diverse structures leave a vast gap between what have been synthesized in laboratory and those present in various biological systems. While enzymes and microbes are nature's catalysts for oligosaccharides, their effective use is not without challenges. Using examples of galactose-containing oligosaccharides, this review analyzes the pros and cons of these two forms of biocatalysts and provides an updated view on the status of biocatalysis in this important field. Over the past few years, a large number of novel galactosidases were discovered and/or engineered for improved synthesis via transglycosylation. The use of salvage pathway for regeneration of uridine diphosphate (UDP)-galactose has made the use of Leloir glycosyltransferases simpler and more efficient. The recent success of large-scale synthesis of 2' fucosyllactose heralded the power of whole-cell biocatalysis as a scalable technology. While it still lags behind enzyme catalysis in terms of the number of oligosaccharides synthesized, an acceleration in the use of this form of biocatalyst is expected as rapid advances in synthetic biology have made the engineering of whole cell biocatalysts less arduous and less time consuming.