The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
The relationships of groups of organisms as reflected by their genetic makeup.
The techniques used to produce molecules exhibiting properties that conform to the demands of the experimenter. These techniques combine methods of generating structural changes with methods of selection. They are also used to examine proposed mechanisms of evolution under in vitro selection conditions.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
The continuous developmental process of a culture from simple to complex forms and from homogeneous to heterogeneous qualities.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Genotypic differences observed among individuals in a population.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Changes in biological features that help an organism cope with its ENVIRONMENT. These changes include physiological (ADAPTATION, PHYSIOLOGICAL), phenotypic and genetic changes.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The process of accumulation of genetic and epigenetic changes over time in individual cells and the effect of the changes on CELL PROLIFERATION.
Chemical and physical transformation of the biogenic elements from their nucleosynthesis in stars to their incorporation and subsequent modification in planetary bodies and terrestrial biochemistry. It includes the mechanism of incorporation of biogenic elements into complex molecules and molecular systems, leading up to the origin of life.
The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
An acquired disorder characterized by recurrent symptoms, referable to multiple organ systems, occurring in response to demonstrable exposure to many chemically unrelated compounds at doses below those established in the general population to cause harmful effects. (Cullen MR. The worker with multiple chemical sensitivities: an overview. Occup Med 1987;2(4):655-61)
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
The aggregate enterprise of manufacturing and technically producing chemicals. (From Random House Unabridged Dictionary, 2d ed)
The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.
A broad class of substances containing carbon and its derivatives. Many of these chemicals will frequently contain hydrogen with or without oxygen, nitrogen, sulfur, phosphorus, and other elements. They exist in either carbon chain or carbon ring form.
Tactical warfare using incendiary mixtures, smokes, or irritant, burning, or asphyxiating gases.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A broad class of substances encompassing all those that do not include carbon and its derivatives as their principal elements. However, carbides, carbonates, cyanides, cyanates, and carbon disulfide are included in this class.
Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
Elements, compounds, mixtures, or solutions that are considered severely harmful to human health and the environment. They include substances that are toxic, corrosive, flammable, or explosive.
Functions constructed from a statistical model and a set of observed data which give the probability of that data for various values of the unknown model parameters. Those parameter values that maximize the probability are the maximum likelihood estimates of the parameters.
Family of the suborder HAPLORHINI (Anthropoidea) comprising bipedal primate MAMMALS. It includes modern man (HOMO SAPIENS) and the great apes: gorillas (GORILLA GORILLA), chimpanzees (PAN PANISCUS and PAN TROGLODYTES), and orangutans (PONGO PYGMAEUS).
The naturally occurring transmission of genetic information between organisms, related or unrelated, circumventing parent-to-offspring transmission. Horizontal gene transfer may occur via a variety of naturally occurring processes such as GENETIC CONJUGATION; GENETIC TRANSDUCTION; and TRANSFECTION. It may result in a change of the recipient organism's genetic composition (TRANSFORMATION, GENETIC).
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
Members of the group of vascular plants which bear flowers. They are differentiated from GYMNOSPERMS by their production of seeds within a closed chamber (OVARY, PLANT). The Angiosperms division is composed of two classes, the monocotyledons (Liliopsida) and dicotyledons (Magnoliopsida). Angiosperms represent approximately 80% of all known living plants.
Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.
Computer-based representation of physical systems and phenomena such as chemical processes.
Animals that have no spinal column.
Elements of limited time intervals, contributing to particular results or situations.
One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.
Chemicals that are used to cause the disturbance, disease, or death of humans during WARFARE.
The total process by which organisms produce offspring. (Stedman, 25th ed)
The splitting of an ancestral species into daughter species that coexist in time (King, Dictionary of Genetics, 6th ed). Causal factors may include geographic isolation, HABITAT geometry, migration, REPRODUCTIVE ISOLATION, random GENETIC DRIFT and MUTATION.
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
The systematic study of the complete DNA sequences (GENOME) of organisms.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
The presence of two or more genetic loci on the same chromosome. Extensions of this original definition refer to the similarity in content and organization between chromosomes, of different species for example.
The genetic complement of a BACTERIA as represented in its DNA.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.
Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.
A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
The origin of life. It includes studies of the potential basis for life in organic compounds but excludes studies of the development of altered forms of life through mutation and natural selection, which is BIOLOGICAL EVOLUTION.
The rate dynamics in chemical or physical systems.
Genes bearing close resemblance to known genes at different loci, but rendered non-functional by additions or deletions in structure that prevent normal transcription or translation. When lacking introns and containing a poly-A segment near the downstream end (as a result of reverse copying from processed nuclear RNA into double-stranded DNA), they are called processed genes.
Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.
The common chimpanzee, a species of the genus Pan, family HOMINIDAE. It lives in Africa, primarily in the tropical rainforests. There are a number of recognized subspecies.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Creation and development of bodies within solar systems, includes study of early planetary geology.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The fluctuation of the ALLELE FREQUENCY from one generation to the next.
The genetic complement of a plant (PLANTS) as represented in its DNA.
A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.
The capability of an organism to survive and reproduce. The phenotypic expression of the genotype in a particular environment determines how genetically fit an organism will be.
A portion of the animal phylum Chordata comprised of the subphyla CEPHALOCHORDATA; UROCHORDATA, and HYPEROTRETI, but not including the Vertebrata (VERTEBRATES). It includes nonvertebrate animals having a NOTOCHORD during some developmental stage.
Proteins found in any species of bacterium.
The functional hereditary units of PLANTS.
Databases devoted to knowledge about specific chemicals.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
A theorem in probability theory named for Thomas Bayes (1702-1761). In epidemiology, it is used to obtain the probability of disease in a group of people with some characteristic on the basis of the overall rate of that disease and of the likelihood of that characteristic in healthy and diseased individuals. The most familiar application is in clinical decision analysis where it is used for estimating the probability of a particular diagnosis given the appearance of some symptoms or test result.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
The discipline studying genetic composition of populations and effects of factors such as GENETIC SELECTION, population size, MUTATION, migration, and GENETIC DRIFT on the frequencies of various GENOTYPES and PHENOTYPES using a variety of GENETIC TECHNIQUES.
A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
Any method used for determining the location of and relative distances between genes on a chromosome.
Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
The branch of science concerned with the interrelationship of organisms and their ENVIRONMENT, especially as manifested by natural cycles and rhythms, community development and structure, interactions between different kinds of organisms, geographic distributions, and population alterations. (Webster's, 3d ed)
Members of the phylum Arthropoda, composed of organisms having a hard, jointed exoskeleton and paired jointed legs. It includes the class INSECTS and the subclass ARACHNIDA, many species of which are important medically as parasites or as vectors of organisms capable of causing disease in man.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
Two identical genes showing the same phenotypic action but localized in different regions of a chromosome or on different chromosomes. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Sexual activities of animals.
A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
The external elements and conditions which surround, influence, and affect the life and development of an organism or population.
A species of fruit fly much used in genetics because of the large size of its chromosomes.
NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.
Cells of the higher organisms, containing a true nucleus bounded by a nuclear membrane.
The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.
The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.
Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
The functional hereditary units of INSECTS.
Communication between animals involving the giving off by one individual of some chemical or physical signal, that, on being received by another, influences its behavior.
Chemical substances that are foreign to the biological system. They include naturally occurring compounds, drugs, environmental agents, carcinogens, insecticides, etc.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.
A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both.
Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
Deoxyribonucleic acid that makes up the genetic material of plants.
Large collections of small molecules (molecular weight about 600 or less), of similar or diverse nature which are used for high-throughput screening analysis of the gene function, protein interaction, cellular processing, biochemical pathways, or other chemical interactions.
Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.
An array of tests used to determine the toxicity of a substance to living systems. These include tests on clinical drugs, foods, and environmental pollutants.
Phylum in the domain Eukarya, comprised of animals either with fully developed backbones (VERTEBRATES), or those with notochords only during some developmental stage (CHORDATA, NONVERTEBRATE).
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
The study of early forms of life through fossil remains.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
The reproductive organs of plants.
Elements that are transcribed into RNA, reverse-transcribed into DNA and then inserted into a new site in the genome. Long terminal repeats (LTRs) similar to those from retroviruses are contained in retrotransposons and retrovirus-like elements. Retroposons, such as LONG INTERSPERSED NUCLEOTIDE ELEMENTS and SHORT INTERSPERSED NUCLEOTIDE ELEMENTS do not contain LTRs.
The science concerned with the detection, chemical composition, and biological action of toxic substances or poisons and the treatment and prevention of toxic manifestations.
Exogenous agents, synthetic and naturally occurring, which are capable of disrupting the functions of the ENDOCRINE SYSTEM including the maintenance of HOMEOSTASIS and the regulation of developmental processes. Endocrine disruptors are compounds that can mimic HORMONES, or enhance or block the binding of hormones to their receptors, or otherwise lead to activating or inhibiting the endocrine signaling pathways and hormone metabolism.
The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)
Coloration or discoloration of a part by a pigment.
A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
Instinctual behavior pattern in which food is obtained by killing and consuming other species.
Insects of the family Formicidae, very common and widespread, probably the most successful of all the insect groups. All ants are social insects, and most colonies contain three castes, queens, males, and workers. Their habits are often very elaborate and a great many studies have been made of ant behavior. Ants produce a number of secretions that function in offense, defense, and communication. (From Borror, et al., An Introduction to the Study of Insects, 4th ed, p676)
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
Cold-blooded, air-breathing VERTEBRATES belonging to the class Reptilia, usually covered with external scales or bony plates.
The complete genetic complement contained in a DNA or RNA molecule in a virus.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
The number of mutations that occur in a specific sequence, GENE, or GENOME over a specified period of time such as years, CELL DIVISIONS, or generations.
The genetic complement of MITOCHONDRIA as represented in their DNA.
Sympathectomy using chemicals (e.g., 6-hydroxydopamine or guanethidine) which selectively and reversibly destroy adrenergic nerve endings while leaving cholinergic nerve endings intact.
The sequential location of genes on a chromosome.
The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.
The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid.
The characteristic three-dimensional shape of a molecule.
One of the three domains of life (the others being BACTERIA and Eukarya), formerly called Archaebacteria under the taxon Bacteria, but now considered separate and distinct. They are characterized by: (1) the presence of characteristic tRNAs and ribosomal RNAs; (2) the absence of peptidoglycan cell walls; (3) the presence of ether-linked lipids built from branched-chain subunits; and (4) their occurrence in unusual habitats. While archaea resemble bacteria in morphology and genomic organization, they resemble eukarya in their method of genomic replication. The domain contains at least four kingdoms: CRENARCHAEOTA; EURYARCHAEOTA; NANOARCHAEOTA; and KORARCHAEOTA.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Theoretical construct used in applied mathematics to analyze certain situations in which there is an interplay between parties that may have similar, opposed, or mixed interests. In a typical game, decision-making "players," who each have their own goals, try to gain advantage over the other parties by anticipating each other's decisions; the game is finally resolved as a consequence of the players' decisions.
Processes that incorporate some element of randomness, used particularly to refer to a time series of random variables.
The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.
The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Time period from 1901 through 2000 of the common era.
The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.
The genetic complement of an insect (INSECTS) as represented in its DNA.
Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.
The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.
Procedures by which protein structure and function are changed or created in vitro by altering existing or synthesizing new structural genes that direct the synthesis of proteins with sought-after properties. Such procedures may include the design of MOLECULAR MODELS of proteins using COMPUTER GRAPHICS or other molecular modeling techniques; site-specific mutagenesis (MUTAGENESIS, SITE-SPECIFIC) of existing genes; and DIRECTED MOLECULAR EVOLUTION techniques to create new genes.
The complete gene complement contained in a set of chromosomes in a fungus.
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
The functional hereditary units of BACTERIA.
Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.
The selection or choice of sexual partner in animals. Often this reproductive preference is based on traits in the potential mate, such as coloration, size, or behavioral boldness. If the chosen ones are genetically different from the rejected ones, then NATURAL SELECTION is occurring.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
General name for two extinct orders of reptiles from the Mesozoic era: Saurischia and Ornithischia.
Sequential operating programs and data which instruct the functioning of a digital computer.
INSECTS of the order Coleoptera, containing over 350,000 species in 150 families. They possess hard bodies and their mouthparts are adapted for chewing.
Established cell cultures that have the potential to propagate indefinitely.
A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
This single species of Gorilla, which is a member of the HOMINIDAE family, is the largest and most powerful of the PRIMATES. It is distributed in isolated scattered populations throughout forests of equatorial Africa.
Complex sets of enzymatic reactions connected to each other via their product and substrate metabolites.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.
Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.
A mammalian order which consists of 29 families and many genera.
The homologous chromosomes that are dissimilar in the heterogametic sex. There are the X CHROMOSOME, the Y CHROMOSOME, and the W, Z chromosomes (in animals in which the female is the heterogametic sex (the silkworm moth Bombyx mori, for example)). In such cases the W chromosome is the female-determining and the male is ZZ. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
A class of unsegmented helminths with fundamental bilateral symmetry and secondary triradiate symmetry of the oral and esophageal structures. Many species are parasites.
Any behavior caused by or affecting another individual, usually of the same species.
Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.
A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
A species of orangutan, family HOMINIDAE, found in the forests on the island of Borneo.
The use of DNA recombination (RECOMBINATION, GENETIC) to prepare a large gene library of novel, chimeric genes from a population of randomly fragmented DNA from related gene sequences.
A small aquatic oviparous mammal of the order Monotremata found in Australia and Tasmania.
Proteins found in any species of insect.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.
Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.
A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.
Presence of warmth or heat or a temperature notably higher than an accustomed norm.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.

UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers. (1/112)

Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.  (+info)

Biochemical evolution III: polymerization on organophilic silica-rich surfaces, crystal-chemical modeling, formation of first cells, and geological clues. (2/112)

Catalysis at organophilic silica-rich surfaces of zeolites and feldspars might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and other geological sources. Crystal-chemical modeling yielded packings for amino acids neatly encapsulated in 10-ring channels of the molecular sieve silicalite-ZSM-5-(mutinaite). Calculation of binding and activation energies for catalytic assembly into polymers is progressing for a chemical composition with one catalytic Al-OH site per 25 neutral Si tetrahedral sites. Internal channel intersections and external terminations provide special stereochemical features suitable for complex organic species. Polymer migration along nano/micrometer channels of ancient weathered feldspars, plus exploitation of phosphorus and various transition metals in entrapped apatite and other microminerals, might have generated complexes of replicating catalytic biomolecules, leading to primitive cellular organisms. The first cell wall might have been an internal mineral surface, from which the cell developed a protective biological cap emerging into a nutrient-rich "soup." Ultimately, the biological cap might have expanded into a complete cell wall, allowing mobility and colonization of energy-rich challenging environments. Electron microscopy of honeycomb channels inside weathered feldspars of the Shap granite (northwest England) has revealed modern bacteria, perhaps indicative of Archean ones. All known early rocks were metamorphosed too highly during geologic time to permit simple survival of large-pore zeolites, honeycombed feldspar, and encapsulated species. Possible microscopic clues to the proposed mineral adsorbents/catalysts are discussed for planning of systematic study of black cherts from weakly metamorphosed Archaean sediments.  (+info)

A possible evolutionary role of formaldehyde. (3/112)

Formaldehyde is a compound which is believed to have had a role in evolutionary processes. On the other hand, the (methyl)glyoxalase pathway is a route being present in all biological organisms whereas its function has not yet been recognized in the biochemical machinery. In this article it is raised that (methyl)glyoxalase path might have functioned as a bridge between formose and archaic reductive citric acid cycles in surface metabolists at the early stage of evolution. According to the theory, formaldehyde was essential for the mentioned system as a raw molecule. Based on thermodynamic calculations a simple way of regulation is also shown. The simplicity of the theory may be in a good agreement with and an explanation of why the (methyl)glyoxalase system is of ubiquitous nature.  (+info)

The Archean sulfur cycle and the early history of atmospheric oxygen. (4/112)

The isotope record of sedimentary sulfides can help resolve the history of oxygen accumulation into the atmosphere. We measured sulfur isotopic fractionation during microbial sulfate reduction up to 88 degrees C and show how sulfate reduction rate influences the preservation of biological fractionations in sediments. The sedimentary sulfur isotope record suggests low concentrations of seawater sulfate and atmospheric oxygen in the early Archean (3.4 to 2.8 billion years ago). The accumulation of oxygen and sulfate began later, in the early Proterozoic (2.5 to 0.54 billion years ago).  (+info)

The origin of intermediary metabolism. (5/112)

The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO(2) and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox couples as the energy source. To inquire into the reaction networks that might emerge, we start with the largest available database of organic molecules, Beilstein on-line, and prune by a set of physical and chemical constraints applicable to the model system. From the 3.5 million entries in Beilstein we emerge with 153 molecules that contain all 11 members of the reductive citric acid cycle. A small number of selection rules generates a very constrained subset, suggesting that this is the type of reaction model that will prove useful in the study of biogenesis. The model indicates that the metabolism shown in the universal chart of pathways may be central to the origin of life, is emergent from organic chemistry, and may be unique.  (+info)

Primordial carbonylated iron-sulfur compounds and the synthesis of pyruvate. (6/112)

Experiments exploring the potential catalytic role of iron sulfide at 250 degrees C and elevated pressures (50, 100, and 200 megapascals) revealed a facile, pressure-enhanced synthesis of organometallic phases formed through the reaction of alkyl thiols and carbon monoxide with iron sulfide. A suite of organometallic compounds were characterized with ultraviolet-visible and Raman spectroscopy. The natural synthesis of such compounds is anticipated in present-day and ancient environments wherever reduced hydrothermal fluids pass through iron sulfide-containing crust. Here, pyruvic acid was synthesized in the presence of such organometallic phases. These compounds could have provided the prebiotic Earth with critical biochemical functionality.  (+info)

Chemical etiology of nucleic acid structure: the alpha-threofuranosyl-(3'-->2') oligonucleotide system. (7/112)

TNAs [(L)-alpha-threofuranosyl oligonucleotides] containing vicinally connected (3'-->2') phosphodiester bridges undergo informational base pairing in antiparallel strand orientation and are capable of cross-pairing with RNA and DNA. Being derived from a sugar containing only four carbons, TNA is structurally the simplest of all potentially natural oligonucleotide-type nucleic acid alternatives studied thus far. This, along with the base-pairing properties of TNA, warrants close scrutiny of the system in the context of the problem of RNA's origin.  (+info)

Novel RNA catalysts for the Michael reaction. (8/112)

BACKGROUND: In vitro selected ribozymes with nucleotide synthase, peptide and carbon-carbon bond forming activity provide insight into possible scenarios on how chemical transformations may have been catalyzed before protein enzymes had evolved. Metabolic pathways based on ribozymes may have existed at an early stage of evolution. RESULTS: We have isolated a novel ribozyme that mediates Michael-adduct formation at a Michael-acceptor substrate, similar to the rate-limiting step of the mechanistic sequence of thymidylate synthase. The kinetic characterization of this catalyst revealed a rate enhancement by a factor of approximately 10(5). The ribozyme shows substrate specificity and can act as an intermolecular catalyst which transfers the Michael-donor substrate onto an external 20-mer RNA oligonucleotide containing the Michael-acceptor system. CONCLUSION: The ribozyme described here is the first example of a catalytic RNA with Michael-adduct forming activity which represents a key mechanistic step in metabolic pathways and other biochemical reactions. Therefore, previously unforeseen RNA-evolution pathways can be considered, for example the formation of dTMP from dUMP. The substrate specificity of this ribozyme may also render it useful in organic syntheses.  (+info)

Looking for online definition of chemical evolution in the Medical Dictionary? chemical evolution explanation free. What is chemical evolution? Meaning of chemical evolution medical term. What does chemical evolution mean?
Science Assignment Help, Chemical evolution of spontaneous generation, Chemical Evolution The question of how life came into being in the first place still remained unanswered. To find an answer to this question means looking back billions of years in time and trying to imagine what the conditions on the earth co
Chemical Evolution. Carbohydrates and Lipids. Biochemistry. Systematic study of the molecular nature of life processes: the chemicals that make up of living systems (biochemicals), their organization into cells, and their chemical interactions Biochemicals have no life in themselves...
4.2. The Halo The Galactic halo does not appear to suffer from a severe G-dwarf problem (Laird et al 1988, Pagel 1989, Beers et al 1992). The halo metallicity ranges from -4 dex to just below the solar value, with a mean of ~ -1.6 (Laird et al 1988, Hartwick 1976), Hartwick (1976) noted that this low metallicity suggested that either the halo yield was much lower than in the disk or that gas was removed from halo star formation (e.g. Ostriker & Thuan 1975). The favored model is that the halo lost its gas before chemical evolution could go to completion. Carney et al (1990), Wyse & Gilmore (1992) suggested that the missing spheroid mass fell to the center of the Galaxy and contributed most of the bulge mass, based on angular momentum considerations. Whether or not there is a minimum metallicity level, below which stars do not exist, has been debated for at least 20 years. Hartquist & Cameron (1977) predicted that there was an era of pregalactic nucleosynthesis by very massive zero metallicity ...
1] We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution, and export of NOx. The boundary layer NOx data provide top-down verification of a 50% decrease in power plant and industry NOx emissions over the eastern United States between 1999 and 2004. Observed NOx concentrations at 8-12 km altitude were 0.55 ± 0.36 ppbv, much larger than in previous U.S. aircraft campaigns (ELCHEM, SUCCESS, SONEX) though consistent with data from the NOXAR program aboard commercial aircraft. We show that regional lightning is the dominant source of this upper tropospheric NOx and increases upper tropospheric ozone by 10 ppbv. Simulating ICARTT upper tropospheric NOx observations with GEOS-Chem requires a factor of 4 increase in modeled NOx yield per flash (to 500 mol/flash). Observed OH ...
Phosphorus No Help for Chemical Evolution One of my favorite blues tunes is Born Under a Bad Sign, a song about someone who just cant catch a break. If there
Modern analytical methods are significantly more sensitive than those used by Miller in the 1950s. Miller used paper chromatography with ninhydrin detection and the mixed melting-point determination of derivatives to identify and quantify organic compounds synthesized in his early experiments. Such techniques would have been able to detect micromolar abundances of a fairly limited range of organic compounds (3). However, the analytical instrumentation used in this study is up to 10 orders of magnitude more sensitive and can detect a much wider diversity of organic compounds than the techniques available in the 1950s (2, 3).. Other efforts have been made to generate organic compounds from simulated early atmospheres containing H2S, most of which were conducted after Millers 1958 experiment. A spark discharge was passed through a mixture of CH4, H2O, NH3, and H2S, but no sulfur amino acids were detected (16). A mixture of H2, CH4, NH3, H2O, and H2S was subjected to a spark discharge, and the ...
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.
Chemical reactions driven by the geological conditions on the early Earth might have led to the prebiotic evolution of self-replicating molecules. Scientists at Ludwig-Maximilians Universitaet (LMU) in Munich now report on a hydrothermal mechanism that could have promoted the process. Life is a product of evolution by natural selection. Thats…
Evolution and Biodiversity, Biological evolution, or evolution is the change in a populations genetic makeup through successive generations., While the Earth itself may be a billion years old, modern humans didnt exist until only 65 million years ago., After this chemical evolution had formed cells, biological evolution took place, creating single-celled prokayotic bacteria into single-celled eukayotic cells., Evidence indicates that Earths life is the result of around 1 billion years of chemical evolution to form the first cells., Origin of Earth, Natural Selection, occurs when some individuals of a population have genetically based traits that increase their chance of survival., If the trait helps the individual significantly, than chances are the rest of the population will develop these characteristics, Adaptive traits are any heritable trait that enables organisms to better survive., In all communities, species all have ecological niches. These are the species role in their environment/community
As the cellular physiology is the outcome of enzymatic activity, so the enzymes must have developed before the cells. Gradually the gene aggregates became surrounded by a complex system of enzymes which formed the cytoplasm. These enzymes could have combined the nitrogen bases, simple sugars and phosphates into the nucleotides. Nucleotides might have combined to form nucleic acid which appear to be the biomolecules fulfilling the condition of supply of replicators in the origin of life. Presently the molecular biology operates on the principle of central dogma which states that flow of genetic informations is unidirectional and is shown as below: DNA (Transcription) → RNA (Translation) → Protein (With genetic informations) (With genetic message) This mechanism probably evolved from much simpler mechanism. Nucleic acid and proteins (enzymes) are two interdependent biomolecules. Proteins are synthesized by a process that begins with the transcription of informations from DNA to mRNA followed ...
In the first paper we showed that you can create tension between a chemical and physical system to give rise to more complex systems. And in the second paper, we showed that these complex systems can have remarkable and unexpected functions, says David Lynn, a systems chemist in Emorys Department of Chemistry who led the research. The work was inspired by our current understanding of Darwinian selection of protein misfolding in neurodegenerative diseases ...
In the first paper we showed that you can create tension between a chemical and physical system to give rise to more complex systems. And in the second paper, we showed that these complex systems can have remarkable and unexpected functions, says David Lynn, a systems chemist in Emorys Department of Chemistry who led the research. The work was inspired by our current understanding of Darwinian selection of protein misfolding in neurodegenerative diseases ...
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Astronomy and Space Physics. Faculty of Science and Technology, Astronomical observatory. ...
Principal Investigator:OZAWA Kazuhito, Project Period (FY):2009 - 2011, Research Category:Grant-in-Aid for Scientific Research (B), Section:一般, Research Field:Petrology/Mineralogy/Science of ore deposit
Intelligent Design or Evolution? examines many unresolved issues associated with chemical evolution, the origin of life, and the evolution of molecular knowledge. With the help of information theory, this book develops statistical models to describe the evolution of the first genes and proteins. It also investigates the chemistry required for the prebiotic synthesis of biological molecules on the primitive earth. The evidence presented will show that naturalistic laws fail to explain the synthesis of RNA, DNA and proteins in the primordial soup. These same laws also fail to explain the origin of life and the evolution of the first genes and proteins. Taken together, these failures imply that life was created.
Intelligent Design or Evolution? examines many unresolved issues associated with chemical evolution, the origin of life, and the evolution of molecular knowledge. With the help of information theory, this book develops statistical models to describe the evolution of the first genes and proteins. It also investigates the chemistry required for the prebiotic synthesis of biological molecules on the primitive earth. The evidence presented will show that naturalistic laws fail to explain the synthesis of RNA, DNA and proteins in the primordial soup. These same laws also fail to explain the origin of life and the evolution of the first genes and proteins. Taken together, these failures imply that life was created.
On this episode of ID the Future, Robert J. Marks interviews Walter Bradley, co-author of the seminal 1984 ID book The Mystery of Lifes Origin, now being released in a revised and expanded edition with updates from multiple contributors discussing the progress (or lack of it) in origins science in the 35 years since the books original publication. Continue reading →. ...
Faculty Applied Sciences. Date 2011-11-08. Abstract Isothermal hydrogen desorption of spark discharge generated Mg/NbOx and Mg/Pd metal hydride nanocomposites is consistently described by a kinetic model based on multiple reaction rates, in contrast to the Johnson-Mehl-Avrami-Kolmogorov [M. Avrami, J. Phys. Chem. 9, 177 (1941); W. A. Johnson and R. F. Mehl, Trans. Am. Inst. Min., Metal. Eng. 135, 416 (1939); A. N. Kolmogorov, Izv. Akad. Nauk SSSR, Ser. Mat. 3, 355 (1937); F. Liu, F. Sommer, C. Bos, and E. J. Mittemeijer, Int. Mat. Rev. 52, 193 (2007)] model which is commonly applied to explain the kinetics of metal hydride transformations. The broad range of reaction rates arises from the disperse character of the particle size and the dendritic morphology of the samples. The model is expected to be generally applicable for metal hydrides which show a significant variation in particle sizes, in configuration and/or chemical composition of local surroundings of the reacting ...
The PAH World is a novel chemical structural model for the plausible formation of oligomeric proto-informational templating materials on the early Earth; presumably progenitors of the widely expected RNA World in chemical evolution theory. The model is based on the self-assembling discotic mesogenic behaviors of polynuclear aromatic compounds, their photochemical edge-derivatizations, and the selectivity of such stacked supramolecular aromatic core scaffolds for the edge-on binding and ~ 0.34 nm plane-parallel spacing of essentially random collections of small prebiotic heterocycles, taken up and concentrated directly from the presumed and surrounding dilute primordial soup. The constrained inter-base separation distance would select for oligomerizing linkers of fairly specific size, such as small methanal oligomers, which would also be taken up from the prebiotic chemical environment, condensing with the small heterocycles and also with each other to form the flexible structural ...
A new robotic system at Georgia Techs Center for Chemical Evolution could soon let scientists better simulate and analyze the chemical reactions of early Earth on the surface of real rocks to further test the theory that catalytic minerals on a meteorites surface could have jump-started lifes first chemical reactions.
Now, researchers working with that hypothesis have achieved a significant advancement toward understanding an evolutionary mystery - how components of RNA and DNA formed from chemicals present on early Earth before life existed.. In surprisingly simple laboratory reactions in water, under everyday conditions, they have produced what could be good candidates for missing links on the pathway to the code of life.. And when those components joined up, the result even looked like RNA.. As the researchers work progresses, it could reveal that much of the original chemistry that led to life arose not in fiery cataclysms and in scarce quantities, but abundantly and gradually on quiet, rain-swept dirt flats or lakeshore rocks lapped by waves.. In turn, their work could increase our understanding of the probability of lifes existence elsewhere in the universe.. The research from the NSF/NASA Center for Chemical Evolution, headquartered at the Georgia Institute of Technology, is generously funded through ...
A new robotic system at Georgia Techs Center for Chemical Evolution could soon let scientists better simulate and analyze the chemical reactions of early Earth on the surface of real rocks.
The whole AronRa video is an excercise in pretending that something that doesnt provide evidence for the supposed steps in abiogenesis/chemical evolution, can be twisted and warped to make it sound like it does (and every detail left out of the story that would suggest otherwise, such as the ones mentioned in the video I shared above but many others as well concerning the meteorites for example, details that even the scientists who have forwarded this research have admitted to in their papers, allthough in a rather deceptive manner turning the world upside down and shifting the burden of proof for them to prove that what they are finding actually was already on or in the meteorite before it landed on earth). I cant quite call it an excercise in bait and switch but its very similar. And before anyone wants to bring up arguments that influence the way people think but dont have much logic to stand on but still forces a response when someone cares about other people not being deceived, ...
I am broadly interested in the chemical evolution of Earths oceans and atmosphere, and the coupling between surface environments and atmospheric composition. I am currently developing and applying novel computational tools for: (1) understanding the role of methane hydrates in Earths carbon cycle; (2) geoengineering of Earths carbon cycle using enhanced silicate weathering (ESW); and (3) estimating the global impacts of non-carbonic acidity on Earths carbon cycle. ...
Earths origin and evolution, isotope and trace element geochemistry, the role of crust and lithospheric mantle recycling in the generation of mantle chemical heterogeneity, the origin and distribution of water and other volatile elements in the Earths interior, and the thermal and chemical evolution of the Earths core and core/mantle ...
Summary The gas and dust in the interstellar medium (ISM) drive the chemical evolution of galaxies, the formation of stars and planets, and the synthesis of complex prebiotic molecules. The prime birth places for this interstellar material are the winds of evolved (super)giant stars. These winds are unique chemical laboratories, in which a large variety of gas and dust species radially expand away from the star. Recent progress on the observations of these winds has been impressive thanks to Herschel and ALMA. The next challenge is to unravel the wealth of chemical information contained in these data. This is an ambitious task since (1) a plethora of physical and chemical processes interact in a complex way, (2) laboratory data to interpret these interactions are lacking, and (3) theoretical tools to analyse the data do not meet current needs. To boost the knowledge of the physics and chemistry characterizing these winds, I propose a world-leading multi-disciplinary project combining (1) ...
1. I have been involved in numerous space based projects that have investigated the emission from cold dust (about 20K) from galaxies. Dust plays an important role in the evolution of the interstellar medium and in the chemical evolution of galaxies as a whole. I led the Herschel Space Telescope survey of the nearby Virgo galaxy cluster in which we consider the dust emission properties of the numerous galaxies of various morphological types. I am the principal investigator of the DustPedia project. DustPedia is a collaboration of six research establishments from across Europe (UK, Belgium, France, Greece and Italy). The project is funded by a European research grant. The objective is to better understand the role dust plays in the interstellar medium via modelling of; dust grain physical properties, spectral energy distributions and a full Monte Carlo radiative transfer analysis. The models are compared with our own extensive database primarily obtained from the Herschel Space Telescope ...
A six-year study of a primordial element created just after the birth of the universe may force scientists to revise theories about how stars and galaxies formed.. Using a telescope sensitive to far ultraviolet light, astronomers have discovered that there is much more deuterium, a heavy form of hydrogen created minutes after the Big Bang, than expected.. Our models of the chemical evolution of the Milky Way will have to be revised significantly, says astrophysicist Professor Jeffrey Linsky with the University of Colorado at Boulder.. All the deuterium that ever existed was believed to have been forged within a few minutes of the Big Bang 13.7 billion years ago. Deuterium is a heavy version of regular hydrogen, the lightest and most abundant element. But its nucleus harbours a neutron in addition to the normal proton, so it is twice hydrogens mass.. Because stars consume deuterium and there is no known process to create more, the isotope serves as a tracer for star formation and galaxy ...
Salt-induced peptide formation reaction has been suggested. to be prebiotically relevant BAY 63-2521 clinical trial for the very first steps of chemical evolution (Schwendinger and Rode 1989). Based on Monte Carlo computer simulations, Rode and co-workers found that sodium chloride at concentrations above 3 M effectively acts as a dehydrating agent to overcome the thermodynamic barrier of peptide bond formation in aqueous solutions, and the first this website hydration shell of the sodium ion was assumed to no longer be saturated with water molecules (Jakschitz and Rode 2012). Furthermore, using HPLC-MS/MS analysis, a high concentration of sodium chloride was found to significantly enhance the formation of peptides from L-glutamic acid (L-Glu) in homogenous water solutions (Wang et al. 2005). All the references we have found that discuss the presence of other mono- and divalent inorganic cations in prebiotic peptide formation speculate that these. ions support the dehydrating effect of sodium ...
A mechanism for creating enantiomerism in the amino acids, the building blocks of the proteins, that involves global selection of one chirality by interactions between the amino acids and neutrinos from core-collapse supernovae is described. The selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the 14N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earths amino acids.
We study astrophysical processes, such as stellar nucleosynthesis and galactic chemical evolution using laboratory analyzis of stardust grains and meteorites.
Context. It is still debated whether or not the Galactic chemical evolution of sulphur in the halo follows the flat trend with [Fe/H] that is ascribed to the result of explosive nucleosynthesis in type II SNe. It has been suggested that the disagreement between different investigations of sulphur abundances in halo stars might be owing to problems with the diagnostics used, that a new production source of sulphur might be needed in the early Universe, like hypernovae, or that the deposition of supernova ejecta into the interstellar medium is time-delayed. Aims. The aim of this study is to try to clarify this situation by measuring the sulphur abundance in a sample of halo giants using two diagnostics: the S I triplet around 1045 nm and the [S I] line at 1082 nm. The latter of the two is not believed to be sensitive to non-LTE effects. We can thereby minimize the uncertainties in the diagnostic used and estimate the usefulness of the triplet for the sulphur determination in halo K giants. We will ...
Using the 8.2-meter Subaru Telescope High Dispersion Spectrograph (HDS), a team of astronomers observed Nova Delphini 2013 and discovered that the outburst is producing a large amount of lithium.. A team of astronomers from National Astronomical Observatory of Japan (NAOJ), Osaka Kyoiku University, Nagoya University, and Kyoto Sangyo University observed Nova Delphini 2013 (Figure 1, 3) which occurred on August 14, 2013. Using the 8.2-meter Subaru Telescope High Dispersion Spectrograph (HDS) to observe this object, they discovered that the outburst is producing a large amount of lithium (Li; Note 1). Lithium is a key element in the study of the chemical evolution of the universe because it likely was and is produced in several ways: through Big Bang nucleosynthesis, in collisions between energetic cosmic rays and the interstellar medium, inside stellar interiors, and as a result of novae and supernova explosions. This new observation provides the first direct evidence for the supply of Li from ...
Transport Modeling Applications The reactive transport capabilities can be used to study contaminant migration of nutrients, metals, radionuclides, and organic compounds; natural and engineered aquifer remediation; diffusion in sediment pore water; the chemical evolution of natural systems; and laboratory column experiments. Description Reactive-transport modeling simulates advection, dispersion, and chemical reactions as water moves through a 1D column. The column is divided into a number of cells, and reactant compositions and nonequilibrium reactions can be defined for each cell. All of the reactants and reactions described for batch reactions can be applied to the cells for transport modeling. The TRANSPORT keyword data block is used to simulate advection and dispersion, or pure diffusion, in the column. The TRANSPORT data block also can be used to simulate a dual-porosity medium, where water flows through the column but simultaneously allows for diffusion into stagnant side pores. The ...
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
Elemental compositions of organic aerosol (OA) particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygento-carbon (O : C), hydrogen-to-carbon (H : C), and organic mass-to-organic carbon (OM : OC) ratios, and of carbon oxidation state (OSC ) for a vastly expanded laboratory data set of multifunctional oxidized OA standards. For the expanded standard data set, the method introduced by Aiken et al. (2008), which uses experimentally measured ion intensities at all ions to determine elemental ratios (referred to here as Aiken-Explicit), reproduces known O : C and H : C ratio values within 20 % (average absolute value of relative errors) and 12 %, respectively. The more commonly used method, which uses empirically estimated H2 O+ and CO+ ion intensities to avoid gas phase air ...
Autocatalysis is essential for the origin of life and chemical evolution. However, the lack of a unified framework so far prevents a systematic study of autocatalysis. Here, we derive, from basic principles, general stoichiometric conditions for catalysis and autocatalysis in chemical reaction networks. This allows for a classification of minimal autocatalytic motifs called cores. While all known autocatalytic systems indeed contain minimal motifs, the classification also reveals hitherto unidentified motifs. We further examine conditions for kinetic viability of such networks, which depends on the autocatalytic motifs they contain and is notably increased by internal catalytic cycles. Finally, we show how this framework extends the range of conceivable autocatalytic systems, by applying our stoichiometric and kinetic analysis to autocatalysis emerging from coupled compartments. The unified approach to autocatalysis presented in this work lays a foundation toward the building of a systems-level ...
I think the major obstacle to chemical evolution is to explain controlled cell growth. I do not know of a reason why, at the early stages of the Earths history, controlled cell growth should replace uncontrolled cell growth (or dominate before it even uncontrolled cell growth even came to be), because exploding and uncontrolled cell growth of a particular species could result be a Darwinian advantage rather a disadvantage. A controlled cell growth of a multicelluar organism would be disrupted after eating cancer cells for breakfast (unless if it had a cure for cancer built in), thus it is unlikely that a controlled cell growth organism could kill a uncontrolled cell growth organism by eating it, nor would it automatically do so. Cancer requires an energy source like any other life. It acquires growth through sugar and fat. Once you got those and some other essentials such as proteins, you can support the growth of cancer. Cancer is not inhibited by a cell clock, which in itself requires ...
Factors involved in the selection of the 20 protein L-α-amino acids during chemical evolution and the early stages of Darwinian evolution are discusse
The s-process or slow-neutron-capture-process is a nucleosynthesis process that occurs at relatively low neutron density and intermediate temperature conditions in stars. Under these conditions heavier nuclei are created by neutron capture, increasing the atomic weight of the nucleus by one. A neutron in the new nucleus decays by beta-minus decay to a proton, creating a nucleus of higher atomic number. The rate of neutron capture by atomic nuclei is slow relative to the rate of radioactive beta-minus decay, hence the name. This process produces stable isotopes by moving along the valley of beta-decay stable isobars in the chart of isotopes. The S-process produces approximately half of the isotopes of the elements heavier than iron, and therefore plays an important role in the galactic chemical evolution. The elements heavier than iron with origins in large stars are typically those produced by the s-process, which is characterized by slow neutron diffusion and capture over long periods in such ...
Jacob, D., J. Crawford, M. Kleb, V. Conners, R. Bendura, J. Raper, G. Sachse, J. Gille, and L. Emmons, The transport and chemical evolution over the Pacific (TRACE-P) mission: Design, execution, and overview of first results, J. Geophys. Res., 108(D20), 8781, doi:10.1029/2002JD003276, in press, 2003 ...
Biomass burning (BB) is a large source of primary and secondary organic aerosols (POA and SOA). This study addresses the physical and chemical evolution of BB organic aerosols. Firstly, the evolution and lifetime of BB POA and SOA signatures observed with the Aerodyne Aerosol Mass Spectrometer are investigated, focusing on measurements at high-latitudes acquired during the 2008 NASA ARCTAS mission, in comparison to data from other field studies and from laboratory aging experiments. The parameter f60 , the ratio of the integrated signal at m/z 60 to the total signal in the organic component mass spectrum, is used as a marker to study the rate of oxidation and fate of the BB POA. A background level of f60 ∼0.3 % ± 0.06 % for SOAdominated ambient OA is shown to be an appropriate background level for this tracer. Using also f44 as a tracer for SOA and aged POA and a surrogate of organic O:C, a novel graphical method is presented to characterise the aging of BB plumes. Similar trends of decreasing f60
The NASA DC-8 and P-3B aircraft flew within about a kilometer or less of each other on three occasions during the Transport and Chemical Evolution Over the Pacific (TRACE-P) campaign in order to intercompare similar measurements on the two aircraft. The first and last intercomparisons were in relatively remote marine environments during transits to and from Asia. The first began with a boundary layer measurement followed by an ascent to 3 km. The second set of intercomparisons was at a fixed altitude of about 5.2 km off the coast of Japan, also in relatively clean air. Finally, the third measurement began at 5.3 km and then descended into the boundary layer. A number of measurements were compared with the best agreement observed for the most abundant compounds such as CO2 and CH4 and with very good agreement for CO, O3, and j values. Other comparisons, including measurements of the same compounds on both aircraft and measurements of the same compound by two different instruments on the DC-8, varied over
Understanding the presuppositions and goals of the researchers to properly read the secular literature carefully, especially with chemical evolution (abiogenesis)
The discovery of numerous planetary systems still in the process of formation provides a unique opportunity to see how our own solar system may have formed 4.6 billion years ago. Our research group studies physical processes that determine thermal environments in and around young planetary systems in order to constrain the prebiotic chemistry which can occur there. In one study we have built a unique code which simulates the heating of dense molecular gas in chemically active outflows (CAOs) associated with protostars. Our code will be used to model the wealth of molecular observations of CAOs which will be obtained by SOFIA and other observatories. In another study we have discovered a new mechanism whereby asteroids in the solar nebula are heated by magnetohydrodynamical processes. The goal of the second study is to determine whether asteroids can be warm enough to support prebiotic chemistry in protoplanetary systems that were not innoculated by short-lived radionuclides such as ...
Experiments have been conducted to try to prove spontaneous generation. Most notably was the famous experiment conducted by Stanley L. Miller and Harold C. Urey in 1953 which attempted to show that given the proper amount of chemicals, heat and electricity, life could eventually arise on its own in a sealed environment. However, this is an example of investigation interference. The chemicals they used to simulate the primordial soup didnt exist in the supplied concentrations, but they were intelligently chosen produce the desired reactions. They withheld oxygen from the experiment since no oxygen can be present for the experiment to work, yet many evolutionists believe some amount of oxygen must have been present in the early earths atmosphere for life to have evolved. They ignored that the very means of producing life (radiation) would also destroy it. They had a mechanism to collect only the amino acids that were produced. No wonder British mathematician, astronomer and astrobiologist ...
The free nucleobases and mononucleotides of RNA do not form Watson-Crick base pairs in water, a fact that presents several challenges for the prebiotic synthesis of RNA. 2,6-Diaminopurine and adenosine-5′-monophosphate (AMP) are shown to form supramolecular assemblies with cyanuric acid in water. These assem Prebiotic chemistry and the molecular origins of life
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 with ammonia and amines, and (b) elucidation of the constraints imposed on the chemistry of the origin of life by the fixed energies and rates of aliphatic organic reactions under mild aqueous conditions. The Sugar Model is a plausible one-pot prebiotic process that converts very simple substrates (formaldehyde, glycolaldehyde, ammonia, and hydrogen sulfide) to a variety of products: small catalytic molecules, energy-rich thioesters and phosphoanhydrides. More recently we showed (a) that homochiral amines (like amino acids and peptides) catalyze the stereoselective synthesis of tetrose sugars from glycolaldehyde, and (b) that sugar-amine (or ...
Author(s): Apel, E. C; Emmons, L. K; Karl, T.; Flocke, F.; Hills, A. J; Madronich, S.; Lee-Taylor, J.; Fried, A.; Weibring, P.; Walega, J.; Richter, D.; Tie, X.; Mauldin, L.; Campos, T.; Weinheimer, A.; Knapp, D.; Sive, B.; Kleinman, L.; Springston, S.; Zaveri, R.; Ortega, J.; Voss, P.; Blake, D.; Baker, A.; Warneke, C.; Welsh-Bon, D.; de Gouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D | Abstract: The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of
A research team of astronomers, mainly from Ehime University and Kyoto University in Japan, has successfully detected a carbon emission line (CIVλ1549) in the most distant radio galaxy known so far in the early universe. Using the Faint Object Camera and Spectrograph (FOCAS) on the Subaru Telescope, the team observed the radio galaxy TN J0924-2201, which is 12.5 billion light years away, and was able to measure its chemical composition for the first time. Their investigation of the detected carbon line showed that a significant amount of carbon existed as early as 12.5 billion years ago, less than a billion years after the Big Bang. This important finding contributes to our understanding of the chemical evolution of the universe and may provide clues about the chemical nature of humans, who are composed of various elements such as carbon and oxygen.. Our universe began with the Big Bang, about 13.7 billion years ago. Hydrogen and helium were the only elements in this newly created universe. If ...
There isnt really a database as you request. Finding the ages of stars is difficult. Only one star has an accurately known age - the Sun. That comes from radioisotope dating of meteorites. For other stars we must rely on models to a greater or lesser extent and we can only estimate an age if the star has a mass or is in a phase of its evolution where things are changing rapidly enough to give some handle on how old it is. For stars at the mass of the Sun or a little bit bigger, one can use evolution in the Hertzsprung-Russell diagram. Stars become more luminous as they burn through their core hydrogen and precise measurements can give an age to about $\pm 1$ Gyr. These are the data that Snaith et al. (2015) use in their paper.. So what Snaith et al. do is they attempt to constrain the star formation history of our Galaxy (or at least stars in the disk of our Galaxy) by making a Galactic Chemical Evolution model that predicts how the abundances of silicon and iron change with time and compare ...
The word evolution is generally taken to mean biological evolution. However, biological evolution is simply the natural consequence of cosmic, stellar, geological, and chemical evolution. From Chaos to Consciousness: A Brief History of the Universe is the story of human evolution in this broader sense of the word. It is a textbook intended for a one-semester course in Astronomy and, after a few introductory chapters on the history of astronomy and the present universe, is narrowly focused on material directly and chronologically related to the eventual rise of conscious beings in the universe.. ...
The word evolution is generally taken to mean biological evolution. However, biological evolution is simply the natural consequence of cosmic, stellar, geological, and chemical evolution. From Chaos to Consciousness: A Brief History of the Universe is the story of human evolution in this broader sense of the word. It is a textbook intended for a one-semester course in Astronomy and, after a few introductory chapters on the history of astronomy and the present universe, is narrowly focused on material directly and chronologically related to the eventual rise of conscious beings in the universe.. ...
Ge/Ch 128. Cosmochemistry. 9 units (3-0-6); first term. Prerequisites: instructors permission. Examination of the chemistry of the interstellar medium, of protostellar nebulae, and of primitive solar-system objects with a view toward establishing the relationship of the chemical evolution of atoms in the interstellar radiation field to complex molecules and aggregates in the early solar system that may contribute to habitability. Emphasis will be placed on identifying the physical conditions in various objects, timescales for physical and chemical change, chemical processes leading to change, observational constraints, and various models that attempt to describe the chemical state and history of cosmological objects in general and the early solar system in particular. Given in alternate years; offered 2017-18. Instructor: Blake. ...
The above-mentioned three examples in-dicate the intricate structure and operation of the cell. No one has any experience of a machine that developed without a design-ers plan and specifications: therefore its reasonable to consider the possibility that such complex arrangements came about by a preconceived design. Unfortunately, such commonsense conclusions have no place in the currently dominant theories about the evolution of life. Rather, the pro-ponents of chemical evolution struggle to manufacture alternative explanations that refer only to blind chance and the imper-sonal laws of physics.. The most common scenario portrayed by chemical-evolution theorists begins more than four billion years ago, when clouds of gases and dust are believed to have con-densed on the earths ancient surface and gradually formed the primal atmosphere. Activated by ultraviolet light and electric bolts, this primitive atmosphere is sup-posed to have spontaneously given birth to organic chemical compounds, ...
Observations and analysis of stellar spectra are the main instrument used for study of the stellar atmospheres. Spectral line formation in the atmosphere of a star is a very complex process and it requires a detailed treatment with non-local thermodynamic equilibrium taken into account for correct interpretation of the observations. In INASAN the comprehensive research in the field of both stellar spectra theory and observations is carried on. The results are successfully applied to study the mechanisms of the anomalies in the chemical composition of atmospheres.. INASAN scientists are involved in various studies related to early stages of protostellar and stellar evolution. Specific research directions include chemical evolution of protostellar clouds and protoplanetary disks, evolution of HII regions, dust formation and destruction in star-forming regions, chemical effect of grain growth in protoplanetary disks, line and continuum radiation transfer in related objects, etc.. More information ...
Melvin Calvin (1911-1997) was awarded the 1961 Nobel Prize in Chemistry for his research on how plants assimilate carbon dioxide. Using the carbon-14 isotope as a tracer, Calvin and colleagues discovered the path followed by carbon through a plant during photosynthesis, starting from its absorption from atmospheric carbon dioxide to its conversion into carbohydrates and other organic compounds. Later, they showed that sunlight helps plants make organic compounds by acting on chlorophyll rather than the absorbed carbon dioxide, as previously believed. This process is called the Calvin cycle. Calvin also studied plant oils as energy sources, the chemical evolution of life, and radiation chemistry ...
X-ray photoelectron spectroscopy (XPS) has been used to investigate the evolution of surface chemistry of YBa2Cu3O7-delta (Y123) films prepared by the metalorganic deposition (MOD) process using trifluoroacetate (TFA) precursors. Detailed XPS core-level spectra obtained from the samples quenched from various points during the calcining and firing stages have been reported for the first time and are used to identify surface species. The XPS data show evidence of formation of intermediate phases such as Y-O-F, BaF2, and CuO during the calcining process, which are the decomposition products of yttrium, barium, and copper trifluoroacetates, respectively. The TFA precursors are completely decomposed at the end of calcination. The change of binding energies for Y 3d(5/2), Ba 3d(5/2), and O ls during the firing process indicates that Y123 starts to form at 800 degrees C after 0.5 h firing. Based on the experimental results, an alternative mechanism of the chemical evolution from precursor to final film in the
The delivery of organic matter to the primitive Earth via comets and meteorites has long been hypothesized to be an important source for prebiotic compounds such as amino acids or their chemical precursors that contributed to the development of prebiotic chemistry leading, on Earth, to the emergence of life. Photochemistry of inter/circumstellar ices around protostellar objects is a potential process leading to complex organic species, although difficult to establish from limited infrared observations only. Here we report the first abiotic cosmic ice simulation experiments that produce species with enantiomeric excesses (e.e.s). Circularly polarized ultraviolet light (UV-CPL) from a synchrotron source induces asymmetric photochemistry on initially achiral inter/circumstellar ice analogs. Enantioselective multidimensional gas chromatography measurements show significant e.e.s of up to 1.34% for (13C)-alanine, for which the signs and absolute values are related to the helicity and number of CPL ...
The delivery of organic matter to the primitive Earth via comets and meteorites has long been hypothesized to be an important source for prebiotic compounds such as amino acids or their chemical precursors that contributed to the development of prebiotic chemistry leading, on Earth, to the emergence of life. Photochemistry of inter/circumstellar ices around protostellar objects is a potential process leading to complex organic species, although difficult to establish from limited infrared observations only. Here we report the first abiotic cosmic ice simulation experiments that produce species with enantiomeric excesses (e.e.s). Circularly polarized ultraviolet light (UV-CPL) from a synchrotron source induces asymmetric photochemistry on initially achiral inter/circumstellar ice analogs. Enantioselective multidimensional gas chromatography measurements show significant e.e.s of up to 1.34% for (13C)-alanine, for which the signs and absolute values are related to the helicity and number of CPL ...
Most of Earths surface water exists in the oceans. But there is a second reservoir of water deep in Earths interior, in the form of hydrogen and oxygen attached to minerals in the mantle.. A new study in AGU Advances, which publishes high-impact, open-access research and commentary across the Earth and space sciences, estimates how much water the mantle potentially could hold today and how much water it could have stored in the past.. The findings suggest that, since early Earth was hotter than it is today, its mantle may have contained less water because mantle minerals hold onto less water at higher temperatures. Assuming that the mantle currently has more than 0.3-0.8 times the mass of the ocean, a larger surface ocean might have existed during the early Archean. At that time, the mantle was about 1,900-3,000 degrees Kelvin (2,960-4,940 degrees Fahrenheit), compared to 1,600-2,600 degrees Kelvin (2,420-4,220 degrees Fahrenheit) today.. If early Earth had a larger ocean than today, that ...
How did life originate on Earth and what were its chemical building-blocks? One possible source of answers to these questions can be found in outer space. On the surface of comets planetary scientists have detected simple organic molecules that could also have been available on the young Earth - either because they were present in the material from which our planet was formed or were subsequently delivered by comets or meteorites.. LMU chemist Thomas Carell and members of his research group have now shown that, under the conditions that prevailed on the young Earth, these simple molecules could indeed have served as precursors for the synthesis of one class of molecules that is an integral part of all forms of life on Earth. In addition, they have validated a plausible reaction mechanism for the production of these compounds. The new findings appear in the leading journal Science.. Before self-replicating systems could be assembled, prebiotic chemistry must first have given rise to the ...
Titan is an analog to the very early Earth, and can provide clues to how life may have arisen on our planet. During its 2.7-year baseline mission, Dragonfly will explore diverse environments from organic dunes to the floor of an impact crater where liquid water and complex organic materials key to life once existed together for possibly tens of thousands of years. Its instruments will study how far prebiotic chemistry may have progressed. They also will investigate the moons atmospheric and surface properties and its subsurface ocean and liquid reservoirs. Additionally, instruments will search for chemical evidence of past or extant life. With the Dragonfly mission, NASA will once again do what no one else can do, said NASA Administrator Jim Bridenstine. Visiting this mysterious ocean world could revolutionize what we know about life in the universe. This cutting-edge mission would have been unthinkable even just a few years ago, but were now ready for Dragonflys amazing flight. Dragonfly ...
1] Here I am giving only one possible scenario, others include protein hypercycles first, then RNA/DNA and protein/RNA co-development.. [2] I am aware that this example required a pre-existing polymerase and that as well as the RNA , a polymerase would have to be around. However, in the prebiotic world this polymerase would not have to be anything like modern polymerases, even clay might do nicely, and so polymerase availability is not as limiting as in a modern example.. [3]Ferris JP, Hill AR Jr, Liu R, and Orgel LE. (1996 May 2). Synthesis of long prebiotic oligomers on mineral surfaces [see comments] Nature, 381, 59-61.. [4]Ekland EH, Szostak JW, and Bartel DP. (1995 Jul 21). Structurally complex and highly active RNA ligases derived from random RNA sequences. Science , 269, 364-70.. [5] See:. Miller SL. (1997 Mar). Peptide nucleic acids and prebiotic chemistry Nat Struct Biol , 4, 167-9.. Hager AJ, and Szostak JW. (1997 Aug). Isolation of novel ribozymes that ligate AMP-activated RNA ...
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The nucleotides of RNA appear to be products of evolution. Experimental studies are showing that plausible proto-nucleotides can be formed in simulated early Earth environments. In turn, these results help to clarify the prebiotic processes that give rise to nucleotides.. ...
Using mud pulled from the bottom of a tropical lake, researchers at have gained a new grasp of how ancient microbes made methane in the complex iron chemistry of the early Earth.
Headline: Bitcoin & Blockchain Searches Exceed Trump! Blockchain Stocks Are Next!. In depth analysis of Prebiotic Ingredients Sales Market is a crucial thing for various stakeholders like investors, CEOs, traders, suppliers and others. The Prebiotic Ingredients Sales Market research report is a resource, which provides technical and financial details of the industry.. Browse more detail information about Prebiotic Ingredients Sales Market at: To begin with, the report elaborates the Prebiotic Ingredients Sales Market overview. Various definitions and classification of the industry, applications of the industry and chain structure are given. Present day status of the Prebiotic Ingredients Sales Market in key regions is stated and industry policies and news are analysed.. Next part of the Prebiotic Ingredients Sales Market Industry analysis report speaks about the manufacturing process. The process is ...
Although controversial, the idea that hydrothermal systems may have been the site for prebiotic synthesis of organic molecules and origin of life is widely supported. For the nascent life to survive, it must have had some sort of metabolic mechanism for generating energy. However, little is known of the specific metabolic pathways utilized by the early life forms or the effect of high temperatures on their activity. Recent research on natural high temperature aquatic environments, though limited because of difficult field logistics and experimental problems, is revolutionizing our understanding of possible energy-generating redox pathways, such as sulphate reduction. An abridged review of research on thermophilic sulphate reduction is presented here. Because of a complex interplay between microbiological and geochemical entities involved, and the uncertainties that modern hydrothermal systems are proxy for biogeochemical conditions on early Earth, great caution is required for interpretation and ...
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ONE of the essential ingredients of life on Earth may have arrived here in iron meteorites. These meteorites would merely have had to react with water to release phosphorus, an element crucial to the working of living cells. Carbon-rich meteorites raining down on Earth about 4 billion years ago are thought to have supplied the …
In conclusion, much elegant work has been done starting from activated mono-nucleotides. However, the prebiotic synthesis of a specific macromolecular sequence does not seem to be at hand, giving us the same problem we have with polypeptide sequences. Since there is no ascertained prebiotic pathway to their synthesis, it may be useful to try to conceive some working hypothesis. In order to do that, I would first like to consider a preliminary question about the proteins we have on our Earth: Why these proteins … and not other ones?. Discussing this question can in fact give us some clue as to how orderly sequences might have originated. […] A grain of sand in the Sahara - This is indeed a central question in our world of proteins. How have they been selected out? There is a well-known arithmetic at the basis of this question, (see for example De Duve, 2002) which says that for a polypeptide chain with 100 residues, 20^100 different chains are in principle possible: a number so large that ...
Video created by The University of Edinburgh for the course Astrobiology and the Search for Extraterrestrial Life. What was the environment of early Earth like when life first emerged and what do we know about life on the earliest Earth? How ...
Recently, Kuhan Chandru and his coworkers2 have suggested that the polymerisation of αHAs may have had a role in the formation of living systems, similarly to the alpha-amino acids (αAAs) that make up modern proteins. Their hypothesis is consistent with the assumption that both αAAs and αHAs are likely to have been common in many primitive solar system environments, as they can be formed from the same mechanisms;3 in fact, lab simulations and the analysis of meteorites suggested that small αHAs and αAAs could be easily produced in those early life contexts. It has also been demonstrated that αHAs are able to polymerize more easily than amino acids under a variety of conditions, including those suggested to exist on primitive planets in the stages when life was originated.4 Besides, the fact that αHAs have been observed in many meteorites suggests that they may also have been efficiently delivered to the primitive Earths surface.5. Thermodynamic studies have shown that, under the same ...
A chemical model that mimics a possible step in the formation of cellular life on Earth four-billion years ago has been developed at Penn State University. The chemists created primitive cell-like structures that they infused with RNA -- the genetic coding material that is thought to precede the appearance of DNA on Earth -- and demonstrated how the molecules would react chemically under conditions that might have been present on the early Earth.
Define prebiotic: of, relating to, or being chemical or environmental precursors of the origin of life; also : existing or … - prebiotic in a sentence
Dive into the research topics of Metamorphism and melting of picritic crust in the early Earth. Together they form a unique fingerprint. ...
In 1963, Dr. Cyril Ponnamperuma managed to synthesize adenine (one of the two most important nucleic acid purine bases) under simulated primitive Earth conditions. The NASA scientist and his three colleagues used a Miller-type apparatus, and began their synthesis with nothing more than methane, ammonia and water in the system. The mixture was bombarded with energetic electrons, and about 0.01% of the carbon in the methane was converted into adenine.304 This is highly significant because adenine is useful, not only for making DNA, but also RNA, ATP, ADP, FAD, and a host of other critical life-molecules.. In a related experiment two years later, Dr. John Oró of the University of Houston and A. P. Kimball produced adenine is a closed reaction system which included ammonia, water, and hydrogen cyanide. Heat was supplied as the energy source, and this time the production of the purine base rose to 0.5% of the available carbon.303 This value was observed over a wide range of chemical conditions, ...
Banatrol Plus with Prebiotic Anti-Diarrhea Contains 2.75 grams of Bimuno prebiotic Controls severity and length of diarrhea All natural and gluten-free Specifications HPIS Classification 440_30_70_0 Latex Free Yes Product Brand Banatrol Product Type Supplement UNSPSC code 42231805
Definition of Prebiotic: A prebiotic is a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth, activity or
From the prebiotic recruitment of the basic building blocks to create life to the transition of their synthesis in living cells, a major problem without invokin
The invention relates to medicine, hepatology and pharmacology and can be used for producing and using a pharmaceutical composition based on a hepatoprotector and a prebiotic for treating and preventi
DuPonts prebiotic fibre could exert positive benefits to the gut microbiome, according to an animal study featured in Nature which also raises future implications on skin, metabolic and even brain health.
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When I got sick, the doctors sent samples to the Federal health authorities for testing. I saw a copy of the report. It said, What the hell is this? written off on one side of the report. Viruses have to go dormant and then mutate in order to flourish. They are the nearest life form on earth to the classic go to infinity, fast model that I talk about all the time. This is rather funny because viruses are one of the oldest life forms if not the oldest. They prefer non-oxygen environments and when mutations in the early earth waters created photosynthesis organisms, these multiplied very rapidly, pushing hard on the viral community ...
Building on earlier experiments showing how lifes chemical building blocks could form from nonliving material on early Earth, this module explores theories on the next steps needed for life. These include the formation of long polymers, which then fold into complex macromolecules. The module describes experiments in an environment like that of primordial Earth, resulting in the spontaneous emergence of phospholipids, which could form into membranes, paving the way for RNA duplication and the eventual emergence of living cells.
Many experiments have indicated that the conditions of the early earth were ideal for the spontaneous formation of biological compounds and perhaps even the first life forms, but as you said that really has little or nothing to do with evolution itself. Evoution is very well-supported by evidence and there are no serious scientific theories that contradict it, so the answer to your question is that its pretty solid ...
Moreover, the yields of intermediate molecules are often in very small quantities mixed with multiple other molecules, many of which are extremely similar to the biologically relevant ones. If the other products were not removed, interfering cross-reactions would block additional progress toward the target molecules. No natural process could have isolated and concentrated an intermediate sufficiently for the next step in any pathway to have commenced at a useful rate. To make any semblance of progress, researchers must resort to relay synthesis where they constantly restart with intermediate molecules in sufficiently high concentrations and purity to force each step to proceed artificially. Even if the series of experimental conditions in a protocol corresponded to actual interlinked environments on the early earth, the requirement of such extreme intervention - what Dr. Tour labeled as cheating - would still completely disconnect the experiments from attempts to identify an undirected route ...
London, UK (SPX) May 26, 2017 - A single process for how a group of molecules called nucleotides were made on the early Earth, before life began, has been suggested by a UCL-led team of researchers. Nucleotides are essential
Provided a minimum of 15 personal qualifying points is achieved in the current month: Sales Assosiates and Sales Managers will qualify for a further discount of 5% of the B.V. value. Sales Executives will qualify for a further discount of 10% of the B.V. value. Directors will qualify for a further discount of 15% of the B.V. value. Director has the potential to earn a further 5% discount of the B.V. value on personal orders, which will be rebated at month end, provided the Director places orders during the month with a combined Customer Retail value of AU$1,000.00 or more.. ...
Living systems (humans) are complex. Changing just one thing is not possible. There are always unintended consequences, some perhaps good and other perhaps not so good.
The pioneering and world-leading research conducted at the University of Exeters state-of-the-art Living Systems Institute (LSI) will form the basis of the latest high-profile Global Conversation event.. Read story ...
A sub-discipline of biology, its focus is in how organisms, organ systems, organs, cells, and biomolecules carry out the chemical or physical functions that exist in a living system.
McKewan, Jaclyn (2009). "Evolution, Chemical". In H. James Birx". Predeterminism. Encyclopedia of Time: Science, Philosophy, ... Steven Pinker's view is that fear of determinism in the context of "genetics" and "evolution" is a mistake, that it is "a ... Gregory W. Graffin and William B. Provine, "Evolution, Religion, and Free Will," American Scientist 95 (July-August 2007), 294- ... where one can try to show that more and more developed products appearing in the evolution of a universe or, simpler, an ...
"Evolution of amphibians". University of Waikato: Plant and animal evolution. Retrieved September 30, 2012.. ... "Journal of Chemical Ecology. 25 (9): 2161-2175. doi:10.1023/A:1021049125805.. ... Patterns of Evolution, as Illustrated by the Fossil Record. Elsevier. pp. 405-420. ISBN 978-0-444-41142-6.. ... "Molecular Phylogenetics and Evolution. 56 (2): 554-561. doi:10.1016/j.ympev.2010.04.019. PMID 20399871.. ...
Venturi S (2011). "Evolutionary Significance of Iodine". Current Chemical Biology. 5 (3): 155-62. doi:10.2174/ ... Venturi, Sebastiano (2014). "Iodine, PUFAs and Iodolipids in Health and Disease: An Evolutionary Perspective". Human Evolution ... and stimulate the evolution of their nervous system transforming the aquatic, vegetarian tadpole into the terrestrial, ...
... has favored the evolution of terrestrial animal species and has likely played a crucial role in the evolution of the human ... Venturi, Sebastiano (2011). "Evolutionary Significance of Iodine". Current Chemical Biology-. 5 (3): 155-162. doi:10.2174/ ... Venturi, Sebastiano (2014). "Iodine, PUFAs and Iodolipids in Health and Disease: An Evolutionary Perspective". Human Evolution- ...
Clonal evolution[edit]. Main article: Somatic evolution in cancer. Just like a population of animals undergoes evolution, an ... The changed cells will divide quicker when the area is damaged by physical, chemical, or viral agents. A vicious circle has ... Clonal evolution[edit]. Main article: Somatic evolution in cancer. While genetic and epigenetic alterations in tumor suppressor ... the process of carcinogenesis is formally a process of Darwinian evolution, known as somatic or clonal evolution.[60] ...
Evolution of their conspicuous coloration is correlated to traits such as chemical defense, dietary specialization, acoustic ... Evolution. 54 (3): 751-763. doi:10.1111/j.0014-3820.2000.tb00077.x. PMID 10937250. Weldon, P.J. (December 2013). "Chemical ... The evolution of warning coloration is not paradoxical". Evolution. 59 (5): 933-940. doi:10.1111/j.0014-3820.2005.tb01032.x. ... "A Review of Chemical Defense in Poison Frogs (Dendrobatidae): Ecology, Pharmacokinetics, and Autoresistance". Chemical Signals ...
2 Actius I, 25, 4 McKewan, Jaclyn (2009). "Evolution, Chemical". In H. James Birx" (ed.). Predeterminism. Encyclopedia of Time ... But the unitary evolution of the wave function is not the entirety of quantum mechanics. Asserting that quantum mechanics is ... "One world versus many: the inadequacy of Everettian accounts of evolution, probability, and scientific confirmation." Many ... then the unitary evolution of the wave function in quantum mechanics, can be said to be deterministic. ...
11, p.4 (1931). (Article) Mason, Stephen (1991). Chemical Evolution. Oxford: Clarendon Press. pp. 236-237. ISBN 0-19-855272-6. ... 125-131 Obituary in the Journal of the Chemical Society, 1872, volume 25, p. 353 Adolph Strecker by B. Lepsius (1892), ...
Chemicals emitted by the orchid act as the fly's sex pheromone precursor or booster. Myophilous plants tend not to emit a ... These plants do not fit into the classical syndromes, though they may show evidence of convergent evolution in their own right ... doi:10.1111/j.1744-7429.2006.00104.x. "The evolution of bat pollination: a phylogenetic perspective". Annals of Botany. 104: ... doi:10.1111/j.1095-8312.2004.00317.x. Stroo, A. (2000). "Pollen morphological evolution in bat pollinated plants". Plant ...
... has favored the evolution of terrestrial animal species and has likely played a crucial role in the evolution of the human ... ISBN 978-0-03-910284-5. Venturi S (2011). "Evolutionary Significance of Iodine". Current Chemical Biology. 5 (3): 155-162. doi: ... Venturi S (2014). "Iodine, PUFAs and Iodolipids in Health and Disease: An Evolutionary Perspective". Human Evolution. 29 (1-3 ...
Several relatively simple chemical tests-commercially available as reagent testing kits-can be used to assess the presence of ... A Radical History of Plants, Drugs, and Human Evolution. New York, New York: Bantam Books. ISBN 978-0-553-37130-7. James W ( ... The chemical structures of psilocybin and related analogs have been used in computational biology to help modeling of the ... 2009). "Chemical interactions with pyramidal neurons in layer 5 of the cerebral cortex: control of pain and anxiety". Current ...
October 19, 2016). "Genome evolution in the allotetraploid frog Xenopus laevis". Nature. 538 (7625): 336-343. doi:10.1038/ ... Venturi, Sebastiano (2011). "Evolutionary significance of iodine". Current Chemical Biology. 5 (3): 155-162. doi:10.2174/ ... Human Evolution. 29 (1-3): 185-205. ISSN 0393-9375. Tamura K, Takayama S, Ishii T, Mawaribuchi S, Takamatsu N, Ito M (2015). " ... and stimulate the evolution of their nervous system transforming the aquatic, vegetarian tadpole into the terrestrial, ...
The evolution of chemical defenses in plants is linked to the emergence of chemical substances that are not involved in the ... Rhoades, David F (1979). "Evolution of Plant Chemical Defense against Herbivores". In Rosenthal, Gerald A.; Janzen, Daniel H. ( ... Within 30 minutes of ingestion the chemical paralyzes the herbivore. While the chemical usually wears off within a few hours, ... ISBN 978-1-4020-3701-6. Dethier, V. G. (March 1954). "Evolution of feeding preferences in phytophagous insects". Evolution. 8 ( ...
"Chemical evolution models". Retrieved 3 March 2017. CS1 maint: discouraged parameter (link) Lai, David K.; Young Sun ... 2003). Abundance ratios and galactic chemical evolution. Annual Review of Astronomy and Astrophysics. 35. 503-556. doi:10.1146/ ... Constraints for Disk Chemical Evolution and Formation". The Astrophysical Journal. 761 (2): 160. arXiv:1112.2214. Bibcode: ... "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s)" (PDF). Astronomy & Astrophysics. 530 ...
"Chemical Evolution: 11. Possible role of hydrogen cyanide in chemical evolution: Investigation of the proposed direct synthesis ... In another series of publications on chemical evolution, Ferris further expanded the understanding of these and other reactions ... He was the editor of Origins of Life and Evolution of Biospheres (OLEB), an academic journal sponsored by The International ... Additionally, his work in atmospheric photochemistry has illuminated many of the chemical processes which occur in the ...
"Chemical Communications. 52 (75): 11195-11198. doi:10.1039/C6CC05303C. PMID 27484884.. *^ Calzaferri, Gion; Méallet-Renault, ... Dempsey, Jillian L.; Brunschwig, Bruce S.; Winkler, Jay R.; Gray, Harry B. (2009). "Hydrogen Evolution Catalyzed by Cobaloximes ... Chemical & Engineering News *^ Calzaferri, Gion (2010). "Artificial Photosynthesis". Topics in Catalysis. 53 (3): 130-140. doi: ... "Physical Chemistry Chemical Physics. 13 (1): 47-57. Bibcode:2011PCCP...13...47K. doi:10.1039/C0CP01163K. PMID 21103567. ...
"Evolution and the tree of life , Biology , Science". Khan Academy. Retrieved 2019-02-20. Heylighen F. "Complexity and Evolution ... Advances in Chemical Physics. 75. pp. 149-263. doi:10.1002/9780470141243.ch4. ISBN 9780470141243. Nowak MA (April 1992). "What ... Quasispecies represents the evolution of high-mutation-rate viruses such as HIV and sometimes single genes or molecules within ... The quasispecies model is a description of the process of the Darwinian evolution of certain self-replicating entities within ...
Chapter 4. Galactic Chemical Evolution" (PDF). Retrieved 13 January 2015.[permanent dead link] Sackmann, I. -J.; Boothroyd, A. ... Planetary nebulae probably play a crucial role in the chemical evolution of the Milky Way by expelling elements into the ... "Planetary nebulae and the chemical evolution of the Magellanic Clouds", Revista Mexicana de Astronomía y Astrofísica, 45: 127- ... In stellar evolution terms, stars undergoing such increases in luminosity are known as asymptotic giant branch stars (AGB). ...
volume= has extra text (help) Connor, R.D. (1995). "The evolution of weighing". Canadian Chemical News. Connor, R.D.; Simpson, ...
The evolution of unpalatablility and the costs of chemical defense in insects. Pages 216 - 244 in B. D. Roitberg and M. B. ... Chemical Ecology of Insects. Chapman and Hall, New York, USA. Guilford, T. 1990. The evolution of aposematism. Pages 23 - 61 in ... Insect Chemical Ecology. Chapman and Hall, New York, USA. Levin, D. (1976). The Chemical Defenses of Plants to Pathogens and ... Plant chemical defenses can be used by herbivores, by storing eaten plant chemicals, and using them in defense against ...
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Dow Chemical Company. Agricultural Products Department; Hugh N. Brown (1985). The Evolution of Agriculture. Midland, MI: Dow ... Midland, MI: Dow Chemical Co. OCLC 54754323. "Guide to the Hugh N. Brown papers" (1997). Prepared for the Ruth Lilly Special ... Dow Chemical Company. Agricultural Products Department; Hugh N. Brown (1986). The History of Farm Implements. ...
Lucas-Lledó JI, Lynch M (May 2009). "Evolution of mutation rates: phylogenomic analysis of the photolyase/cryptochrome family ... Sancar A (June 2003). "Structure and function of DNA photolyase and cryptochrome blue-light photoreceptors". Chemical Reviews. ... ". Molecular Biology and Evolution. 26 (5): 1143-53. doi:10.1093/molbev/msp029. PMC 2668831. PMID 19228922. ...
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"Nucleosynthesis and chemical evolution of galaxies. pp. 154-160. ISBN 978-0-521-55958-4. .. ... "Journal of the Chemical Society. 57: 749-753. doi:10.1039/CT8905700749.. *^ Kerfoot, Derek G. E. "Nickel". Ullmann's ... Nickel is a chemical element with the symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden ... a b Globally Harmonised System of Classification and Labelling of Chemicals (GHS) Archived August 29, 2017, at the Wayback ...
ISBN 978-981-256-801-4. McCapra, Frank (1976). "Chemical mechanisms in bioluminescence". Accounts of Chemical Research. 9 (6): ... Molecular Biology and Evolution. 22 (7): 1543-1545. doi:10.1093/molbev/msi155. PMID 15858206. Shimomura, Osamu (2006). "The ... It produces a blue-coloured light by a specialized chemical reaction of the substrate luciferin and the enzyme luciferase. The ... ostracod Cypridina (Vargula) and other luminous crustaceans". Bioluminescence: chemical principles and methods. World ...
"ACS Chemical Biology. 11 (10): 2908-2914. doi:10.1021/acschembio.6b00624. PMC 5074845. PMID 27571266.. ... Over the course of vertebrate evolution, a number of positions have been chosen for placement of the third hydroxyl group. ... Physical-chemical and thermodynamic considerations". Arch Intern Med. 130 (4): 506-27. doi:10.1001/archinte.1972.03650040040005 ...
These include depression, food allergies, ingestion of certain chemicals, bulimia, anorexia nervosa, pituitary gland ... "Energetics and the evolution of body size in small terrestrial mammals" (PDF). Symposia of the Zoological Society of London ... "Déjà vu: the evolution of feeding morphologies in the Carnivora". Integrative and Comparative Biology. 47 (1): 147-163. doi ...
Trends in Ecology and Evolution. 20 (6): 345-353. doi:10.1016/j.tree.2005.04.004. PMID 16701391. Archived from the original ( ... These chemical reactions require energy, which mainly comes from the Sun and largely by photosynthesis, although a very small ... Trends in Ecology and Evolution. 17 (6): 269-277. doi:10.1016/S0169-5347(02)02455-2. Archived from the original (PDF) on 2011- ... Post, D. M. (1993). "The long and short of food-chain length". Trends in Ecology and Evolution. 17 (6): 269-277. doi:10.1016/ ...
... "a Vascon expansionism in Aquitany is not proved and is not necessary to understand the historical evolution of this region".[1] ... chemicals. *aerospace industry. *wood products and packaging. *food processing. *metallurgy. References[edit]. *^ Juan José ...
Journal of Chemical Neuroanatomy". 34 (3-4), s. 80-94, 2007. DOI: 10.1016/j.jchemneu.2007.05.004. PMID: 17560075 (ang.). ... Molecular Phylogenetics and Evolution". 1 (2), s. 148-146, 1992. DOI: 10.1016/1055-7903(92)90026-D. PMID: 1342928 (ang.). ... Journal of Chemical Neuroanatomy". 34 (3-4), s. 108-127, 2007. DOI: 10.1016/j.jchemneu.2007.05.006. PMID: 17624722 (ang.). ... Molecular Biology and Evolution". 22 (9), s. 1869-86, 09-2005. DOI: 10.1093/molbev/msi180. PMID: 15930153 (ang.). ...
Engelmoer DJ, Rozen DE (December 2011). "Competence increases survival during stress in Streptococcus pneumoniae". Evolution. ... "Studies on the chemical nature of the substance inducing transformation of pneumococcal types: induction of transformation by ...
Raviña, Enrique (2011). "Vinca alkaloids". The evolution of drug discovery: From traditional medicines to modern drugs. John ... Accounts of Chemical Research. 48 (3): 653-662. doi:10.1021/ar500400w.. ...
Multiple chemical sensitivity. ReferencesEdit. *^ Shettleworth, S. J. (2010). Cognition, Evolution and Behavior (2nd ed.). New ... Electrical or chemical stimulation of the rat hippocampus causes strengthening of synaptic signals, a process known as long- ... and some medically unexplained syndromes such as fibromyalgia and multiple chemical sensitivity. Sensitization may also ...
Recent experiments have attempted to develop this chemical as a treatment to avoid disfiguring skin contractions after skin ... Reports to the Evolution Committee, Royal Society of London 3. *^ Dawn Edwards. Developing a yellow sweet pea ...
2004). The Evolution of Plant Physiology. Academic Press. ISBN 978-0-08-047272-0. .. ... The sugars are then stored as starch, further processed by chemical synthesis into more complex organic molecules such as ... In the course of evolution, leaves have adapted to different environments in the following ways:[citation needed] ... Stewart, Wilson N; Rothwell, Gar W. (1993) [1983]. Paleobotany and the Evolution of Plants (2nd ed.). Cambridge University ...
Viral replication triggers high levels of inflammatory chemical signals and leads to a septic state.[38] ... and rapid evolution death after a mean of three days."[163] ...
It is a case of co-evolution. Senses and skeletal system[change , change source]. Amphibians' eyes have lids, glands and ducts ... They like to eat earthworms and will find them by picking up their chemical signals. Salamanders and newts are fed a lot of ... The rise of amphibians: 365 million years of evolution. Baltimore: The Johns Hopkins University Press. ISBN 978-0-8018-9140-3 ... Carroll, Robert L. (2009), The rise of amphibians: 365 million years of evolution, The Johns Hopkins University Press, ISBN 978 ...
"Genome Biology and Evolution. 10 (10): 2669-2571. doi:10.1093/gbe/evy189. PMC 6166771. PMID 30165616.. ... "Effect of chemical mutagens on nucleotide sequence". Biocyclopedia. Retrieved 24 October 2015.. ... Takenaka M, Zehrmann A, Verbitskiy D, Härtel B, Brennicke A (2013). "RNA editing in plants and its evolution". Annual Review of ... Krause K (September 2008). "From chloroplasts to "cryptic" plastids: evolution of plastid genomes in parasitic plants". Current ...
Chelikowski, J. (2004) "Introduction: Silicon in all its Forms", p. 1 in Silicon: evolution and future of a technology. P. ... "Nanofluidic transistor, the basis of future chemical processors". Archived from the original on July 2, 2012 ...
Taxonomy and evolutionEdit. The scientific name of the black wildebeest is Connochaetes gnou. The animal is placed in the genus ... Hoffman, L. C.; Van Schalkwyk, S.; Muller, N. (October 2009). "Effect of season and gender on the physical and chemical ... This evolution is quite recent on a geologic time scale.[9] ... evolution (doctoral dissertation)".. *^ a b c d e f g h i ...
This means evolution, population biology, organismal biology and biological diversity. It was first awarded in 1890. It comes ... In recognition of her discovery of and continuing work on chemical mutagenesis. ... Distinguished for his work on molecular evolution, in particular on the role of stochastic events in determining the rate of ... for their fundamental work on the ecology, breeding and evolution of Darwin's finches on the Galapagos islands. This work has ...
"Human Evolution". History Channel. Archived from the original on 23 April 2008. Retrieved 17 May 2008.. ... Kurzweil is also known for his history of the universe in six epochs: (1) the physical/chemical epoch, (2) the life epoch, (3) ... The use of tools by early humans was partly a process of discovery and of evolution. Early humans evolved from a species of ... "Evolution of Modern Humans: Archaic Homo sapiens Culture". Palomar College. Retrieved 31 March 2007.. ...
David Enrich, Kucinich's Continued Evolution National Review, June 9, 2003 *^ "Rep. Kucinich introduces Bush impeachment ... "Bashar-al Assad tells Dennis Kucinich that jihadists used chemical weapons in Syria (video)". Retrieved 2018-02- ...
Genomics and knowledge of human genetics and human evolution is having increasingly significant influence on medicine, as the ... especially the structure and function of their chemical components. ... evolution, and genetics are influencing medical technology, practice and decision-making. ...
Mineralogical and chemical analysis of these coprolites indicates that if the referral to Herrerasaurus was correct, this ... Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology. 69 ... Benton, Michael J. (1999). "Origin and early evolution of dinosaurs". In Farlow, James O.; Brett-Surman, M.K. The Complete ... Parrish, J. Michael (1999). "Evolution of the archosaurs". In Farlow, James O.; Brett-Surman, M.K. The Complete Dinosaur. ...
Cyanobacterial evolution from comparative genomicsEdit. This section reads like it's been copied verbatim from a scientific ... the bacteria do not use or produce cyanide whose chemical prefix is cyano-." Is this addendum really necessary? I doubt that ... Recognizing and interpreting the fossils of early eukaryotes Javaux EJ, Knoll AH, Walter M ORIGINS OF LIFE AND EVOLUTION OF THE ... Steele A ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE 34 (1-2): 257-269 FEB 2004 ...
Yu SB, Watson AD (September 1999). "Metal-Based X-ray Contrast Media". Chemical Reviews. 99 (9): 2353-78. doi:10.1021/cr980441p ... Quader MA, Sawmiller CJ, Sumpio BE (2000). "Radio Contrast Agents: History and Evolution". Textbook of Angiology. pp. 775-783. ...
Using chemical proxies from Antarctic ice cores, researchers have estimated the fluctuations of carbon dioxide (CO2) and ... Graham, R. W.; Mead, J. I. (1987). "Environmental fluctuations and evolution of mammalian faunas during the last deglaciation ... The research -- published Monday in Nature, Ecology & Evolution journal -- found that 571 plant species have disappeared from ... Journal of Human Evolution. 47 (1-2): 25-63. doi:10.1016/j.jhevol.2004.05.005. PMID 15288523.. ...
Stroo, A. (2000). "Pollen morphological evolution in bat pollinated plants". Plant Systematics and Evolution. 222 (1-4): 225- ... Journal of Chemical Ecology. 32 (11): 2429-2441. doi:10.1007/s10886-006-9154-4. PMID 17082990.. CS1 maint: multiple names: ... The growth of biological thought: diversity, evolution and thought. Harvard University Press, 659. ... Flowering plants: evolution above the species level. Harvard University Press. .mw-parser-output cite.citation{font-style: ...
Journal of Chemical Education. American Chemical Society. 80 (8): 952-961. Bibcode:2003JChEd..80..952J. doi:10.1021/ed080p952. ... but the planets acquired different compositions during the formation and evolution of the solar system. In turn, the natural ... Physical and chemicalEdit. The physical and chemical properties of the alkali metals can be readily explained by their having ... Connelly, Neil G.; Geiger, William E. (1996). "Chemical Redox Agents for Organometallic Chemistry". Chemical Reviews. 96 (2): ...
Necrotic cells send the wrong chemical signals which prevent phagocytes from disposing of the dead cells, leading to a buildup ... Neurosurgeons take the time to observe the evolution of the neoplasm before proposing a management plan to the patient and his/ ...
Chemical depilatory untuk pemindahan rambut: Pada abad ke-9, Ziryab mengajar para wanita di Al-Andalus "pembentukan bulu mata ... Rosheim, Mark E. (1994), Robot Evolution: The Development of Anthrobotics, Wiley-IEEE, m/s. 9-10, ISBN 0471026220. ... Ahmad Y Hassan (1987), "Chemical Technology in Arabic Military Treatises", Annals of the New York Academy of Sciences, New York ... Rosheim, Mark E. (1994), Robot Evolution: The Development of Anthrobotics, Wiley-IEEE, m/s. 9, ISBN 0471026220. ...
For air, n − 1 is proportional to the density of the gas as long as the chemical composition does not change.[42] This means ... "The Evolution of the Abbe Refractometer". Humboldt State University, Richard A. Paselk. 1998. Archived from the original on ... This type of devices are commonly used in chemical laboratories for identification of substances and for quality control. ... chemical and pharmaceutical industry for process control. ...
A chemical mechanism in the pollen is active in many species to avoid selfing. Two notable exceptions are exclusive self ... Early classifications depended on morphological comparison only, but because of extensive convergent evolution, these do not ... Parasitoid wasps that feed on such insect herbivores are attracted to the chemical compounds released by the plants, and thus ... to its secretion of allelopathic chemicals. These inhibit the germination of most competing plants and kill beneficial soil ...
Huizenga 1993, p. viii "Enhancing the probability of a nuclear reaction by 50 orders of magnitude (...) via the chemical ... There are also "heat-after-death" experiments, where the evolution of heat is monitored after the electric current is turned ... "Cold fusion' rebirth? New evidence for existence of controversial energy source", American Chemical Society. ... On 22-25 March 2009, the American Chemical Society meeting included a four-day symposium in conjunction with the 20th ...
Provocative Prescription for Chemical Evolution in Plants. Researchers speculate "specialized metabolism" was key to ... One pathway--having chemical processes termed primary metabolism--allowed the production of life-sustaining chemicals. ... The other pathway produced chemicals that no longer carry life sustaining functions. Instead, these chemicals have more subtle ... As primary metabolism produced life-sustaining chemical reactions, specialized metabolism gave rise to secondary chemical ...
Chemical communication is crucial for the maintenance of colony organization in eusocial insects and chemical signals are known ... Chemical communication is crucial for the maintenance of colony organization in eusocial insects and chemical signals are known ... Monnin T (2006) Chemical recognition of reproductive status in social insects. Ann Zool Fenn 43:515-530Google Scholar ... Holman L, Lanfear R, dEttorre P (2013) The evolution of queen pheromones in the ant genus Lasius. J Evol Biol 26:1549-1558. ...
We introduce a simple model describing the evolution of a population of information-carrying macromolecules. We discuss the ... Anderson PW (1983) Suggested model for prebiotic evolution: the use of chaos. Proc Natl Acad Sci USA 80:3386-3390PubMedCrossRef ... Amitrano C, Peliti L, Saber M (1988) Neutralism and adaptation in a simple model of molecular evolution. C R Acad Sci Paris III ... Kauffman SA (1988) Origins of order in evolution: self-organization and selection. In: Livi R, Ruffo S, Ciliberto S, Buiatti M ...
However, Chemical Ecology concerns the developmental, behavioral and ecological consequences of chemical signals and goes ... The language connecting all living organisms is chemical - this section is devoted to chemical communication between plants, ... Microbial Chemical Ecology is now taking center stage, since interactions with bacteria, fungi or yeasts are widespread ... Chemical Ecology welcomes submissions of the following article types: Brief Research Report, Correction, Data Report, Editorial ...
University scientists sniff out the evolution of chemical nociception. The basis of detecting tissue-damaging chemicals goes ... Chemical nociception, the detection of tissue-damaging pungent chemicals like those found in wasabi, tear gas and cigarette ... your response is being triggered by a primordial chemical sensor conserved across some 500 million years of animal evolution, ... In humans, chemical nociception causes pain and inflammation.. "What the study, spearheaded by Kyeongjin Kang in my lab, shows ...
... evolution at the scale of molecules Oxygen evolution, the process of generating molecular oxygen through chemical reaction ... Chemical evolution may refer to: Abiogenesis, the transition from nonliving elements to living systems Astrochemistry, the ... the study of the chemical compositions in the universe and the processes that led to them Evolution of metal ions in biological ... stellar thermonuclear fusion or supernovae This disambiguation page lists articles associated with the title Chemical evolution ...
Read more for free in Chemical Science or check out the news story on the EPFL website. ... Expanding the pleuromutilin class of antibiotics by de novo chemical synthesis. Register now for ISACS meetings to receive ... Amorphous molybdenum sulfide films are highly active hydrogen evolution catalysts, say researchers from Switzerland. ...
This review focuses on the effectiveness of chemical modifications on the evolution of nucleic acids as functional molecules ... Indeed, in the past two decades, random screening involving chemical modification, post-SELEX chemical modification, and ... Chemical modification would be a key means to further increase their performance, e.g., expansion of function diversity, ... These methods have helped explore the potential abilities of nucleic acids and steadily contributed to their evolution, i.e., ...
... By Fazale Rana - February 8, 2016 ... The USF and GT researchers have identified a chemical process that could, in principle, yield key organic phosphates. However, ... strides towards understanding how organic phosphates formed on early Earth and provided support for chemical evolution and ... Another problem origin-of-life researchers have identified with this chemical route relates to phosphates solubility. These ...
Nanocatalysts for Hydrogen Evolution Reactions K. Ojha, S. Saha, P. Dagar and A. Ganguli, Phys. Chem. Chem. Phys., 2018, ... key concepts and current status of the research on the properties of nanocatalysts that influence the hydrogen evolution ...
Development of air-stable hydrogen evolution catalysts B. Mondal and A. Dey, Chem. Commun., 2017, 53, 7707 DOI: 10.1039/ ...
Convergent evolution of herbivore chemical ecology. Douglas B. Rasher, E. Paige Stout, Sebastian Engel, Tonya L. Shearer, Julia ... Convergent evolution of herbivore chemical ecology. Douglas B. Rasher, E. Paige Stout, Sebastian Engel, Tonya L. Shearer, Julia ... Marine and terrestrial herbivores display convergent chemical ecology despite 400 million years of independent evolution. ... Marine and terrestrial herbivores display convergent chemical ecology despite 400 million years of independent evolution ...
Photochemical Reactions and the Chemical Evolution of Purines and Nicotinamide Derivatives. By J. P. Ferris, J. E. Kuder, A. W ... Photochemical Reactions and the Chemical Evolution of Purines and Nicotinamide Derivatives. By J. P. Ferris, J. E. Kuder, A. W ... Photochemical Reactions and the Chemical Evolution of Purines and Nicotinamide Derivatives Message Subject. (Your Name) has ...
The favored model is that the halo lost its gas before chemical evolution could go to completion. Carney et al (1990), Wyse & ... 3 relative to a Simple one-zone model of chemical evolution; this was attributed to a reduced efficiency of forming low-mass ...
Simulation of the chemical evolution of biomass burning organic aerosol Georgia N. Theodoritsi1,2 and Spyros N. Pandis1,2,3 ... How to cite: Theodoritsi, G. N. and Pandis, S. N.: Simulation of the chemical evolution of biomass burning organic aerosol, ... 1Department of Chemical Engineering, University of Patras, Patras, Greece. *2Institute of Chemical Engineering Sciences, ... 1Department of Chemical Engineering, University of Patras, Patras, Greece. *2Institute of Chemical Engineering Sciences, ...
Evolution and Genetics. Evolution and Genetics. Genetics, Evolution, Virology, Genomics. OCallaghan, Dr Rachel. Senior ... Evolution and Genetics. Evolution and Genetics. Evolution, Genetics, Speciation, Domestication. Garnett, Dr James. Early Career ... Evolution and Genetics. Evolution and Genetics. Ecology, Evolution, Infectious Disease, Parasite, Immunity, Sexual Selection. ... Evolution and Genetics. Evolution and Genetics. Tree, Genomics, Ash Dieback, Evolution, Ecology, Genetics. ...
Scientists use directed evolution to develop better viruslike capsules. Artificial viral capsids that hold their own genomic ... The development opens the door for researchers to use directed evolution, a repetitive protein mutation . . . ...
New synthesis of convergent evolution!. Posted on July 22, 2017. by Anurag Agrawal - No Comments ↓ ... Insects on Plants, Chemical Ecology, and Coevolution. Website of the Phytophagy Lab at Cornell University, led by Anurag ... Convergent Phenotypic Evolution despite Contrasting Demographic Histories. in the Fauna of White Sands. Erica Bree Rosenblum, ... Pattern and Process in the Comparative Study of Convergent Evolution. D. Luke Mahler, Marjorie G. Weber, Catherine E. Wagner, ...
Systematic study of the molecular nature of life processes: the chemicals that make up of living systems (biochemicals), their ... organization into cells, and their chemical interactions Biochemicals have no life in themselves... ... Chapter 14 - Principles of Evolution -. what is evolution? where did the concept of evolution come from? how does evolution ... Evolution -. evolution and the theory of natural selection . what is evolution?. the change in gene frequencies in a population ...
... Ryde, Nils Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, ...
The Planet formation and evolution group at Queen Mary is involved in world leading theoretical and observational research in ... planet formation and evolution, both within our own Solar system and beyond. We are involved in the Red Dots program, which has ...
Periodic Reporting for period 2 - SynPlex (Tailored chemical complexity through evolution-inspired synthetic biology). ... Nature Chemical Biology, Proc. Natl. Acad. Sci. U. S. A., Angewandte Chemie (3x), and ACS Chemical Biology. In addition, we ... To realize this goal, the project aims to (i) identify global patterns of PKS evolution across bacteria, (ii) identify PKS ... The SynPlex project aims to understand the principles of how modular enzyme reorganization during natural evolution resulted in ...
Thus, we re-investigated the effect of oxygen on metabolic evolution using a phylogenetic comparative method and metadata ... These findings indicate that the contribution of oxygen to increased chemical diversity in metabolic networks is lower than ... However, this conclusion does not contradict the effect of oxygen on metabolic evolution; instead, it provides a deeper ... Furthermore, we showed that previous studies have overestimated or underestimated the degrees of differences in the chemical ...
Directed evolution strategies for enantiocomplementary haloalkane dehalogenases: from chemical waste to enantiopure building ... We used directed evolution to obtain enantiocomplementary haloalkane dehalogenase variants that convert the toxic waste ... After five rounds of evolution with screening of only 5500 clones, we obtained two strongly diverged haloalkane dehalogenase ... of all 16 noncatalytic active-site residues during the initial two rounds of evolution. The resulting best R- and S- ...
... Proc Natl Acad Sci U S A. 2015 ... We used this method to infer the evolution of type II polyketide gene clusters, tracing the path of evolution from the single ... gene swaps were likely a key to evolution of chemical diversity. The lessons learned about how natural selection drives ... We developed an approach to study the evolution of biosynthetic genes on a cluster-wide scale, integrating pairwise gene ...
... chemical-sensitive 3-D imaging offers clues for reducing cost/improving performance of catalysts for fuel-cell-powered vehicles ... Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D. (Nanowerk News) Catalysts are at the ... The scientists used chemical-sensitive electron tomography, which is a nanoscale version of a CAT scan, to track what was ... The scientists also used "electron energy loss spectroscopy" and the distinct "chemical fingerprints" of nickel and cobalt to ...
But there is a much deeper problem with theories of chemical evolution, as well as biological evolution. This pertains not just ... Evolution Problem 2: Unguided Chemical Processes Cannot Explain the Origin of the Genetic Code. Casey Luskin ... "The Top Ten Scientific Problems with Biological and Chemical Evolution," in the volume More than Myth, edited by Paul Brown and ... For one, the first RNA molecules would have to arise by unguided, non-biological chemical processes. But RNA is not known to ...
The field of planetary biology and chemical evol... ... Implications for Chemical Evolution and the Origin of Life: ... To understand how the conditions for chemical evolution and the origin of life were influenced by the physical and chemical ... Prebiological chemical evolution and the origins of life could have oc- curred at any time after Earth accreted. If the ... Prospects for Chemical Evolution and the Origin of Life on Mars Among all the scientific opportunities provided by NASAs space ...
Chemical communication is mediated by signal production and signal perception and in house mice (Mus musculus), both processes ... Chemical communication is mediated by signal production and signal perception and in house mice (Mus musculus), both processes ... Logan, D. W., Marton, T. F., and Stowers, L. (2008). Species specificity in major urinary proteins by parallel evolution. PLoS ... Chemical communication is mediated by signal production and signal perception and in house mice (Mus musculus), both processes ...
... chemical recycling could change the polymers long-term sustainable equation. ... The Sustainable Packaging Evolution: Ineos, PS, and Chemical Recycling. As the coronavirus crisis casts polystyrene and PS ... With chemical recycling, these disadvantages are removed, allowing for more polystyrene items to be added to consumer, ... Second, chemical recycling can handle mild contamination from food residue, dirt, etc. With traditional mechanical recycling, ...
  • Noel, along with Jing-Ke Weng and Ryan Philippe also with the Salk Institute, theorize that a very early form of chemical reactions that occurred in the prebiotic soup paved the way for production of chemicals important to the survival of the earliest cellular organisms--chemicals including those essential for building nucleic acids--biological molecules such as DNA, RNA and proteins necessary for encoding, transmitting and expressing genetic information. (
  • According to the researchers, specialized metabolism likely permitted more and varied chemical reactions and natural products because the enzymes responsible for their synthesis were more flexible in ways scientists are only now beginning to understand at the molecular level. (
  • As primary metabolism produced life-sustaining chemical reactions, specialized metabolism gave rise to secondary chemical reactions that allowed plants to adapt to geographically dispersed environments, many of which are challenging to other forms of life. (
  • Phosphorylation reactions are the chemical processes that generate organic phosphates in the cell. (
  • According to conventional thinking among origin of life theorists, life arose via unguided chemical reactions on the early Earth some 3 to 4 billion years ago. (
  • Reducing gasses are those which tend to donate electrons during chemical reactions. (
  • I have heard - I think from Neil deGrasse Tyson - that carbon is involved in over half of all known chemical reactions. (
  • As far as chemical evolution, what we need is to get from basic natural chemical reactions to a self-replicating molecule. (
  • The Oxygen Evolution and Oxygen Reduction Reactions (OER/ORR), occurring at the oxygen electrode of Solid Oxide Cells (SOCs) in the two possible ways of operation, require substantial overpotentials, therefore lowering the operating efficiency of the cells. (
  • In their new work, Thomas Carell and his team propose a cascade of chemical reactions in which the four different components of the hereditary molecule RNA can all be produced under identical early Earth conditions: the primordial soup - cooked in one pot, so to speak. (
  • The chain of chemical reactions was driven only by wet-dry cycles, such as those caused by hydrothermal sources or periods of drought or rain. (
  • In contrast, naturalists typically believe that life descended from a single self-replicating protocell which in turn came into existence through spontaneous chemical reactions . (
  • Only those types of chemical reactions are discussed which are linked to the topic of chemical equilibrium. (
  • The chemical reactions in which heat is evolved are called exothermic reactions. (
  • RNA proteins, etc.) by chemical evolution through a series of chemical reactions about 4 billion years ago (in the Precambrian period) (i.e. about 500 million years after the formation of earth). (
  • This set the stage for various chemical reactions. (
  • Simple organic compounds showed chance chemical reactions and polymerisation to finally form complex organic compounds like polysaccharides, fats, nucleotides, nucleic acids, polypeptides etc. (
  • Main energy sources for the chemical reactions and the formation of polymers were: electrical discharge, lightning, solar energy, ATP and pyrophosphates. (
  • To realize this goal, the project aims to (i) identify global patterns of PKS evolution across bacteria, (ii) identify PKS enzymes and modules with new functions to create a synthetic biology toolbox, (iii) develop a bacterial production host for hybrid PKSs, and (iv) to characterize the recombinant polyketides. (
  • The Beilstein Bozen Symposium 2018 on Information and Noise: Chemistry, Biology and Evolution Creating Complex Systems will be held on 5-7 June 2018, in the Hotel Jagdschloss Niederwald, Rüdesheim, Germany. (
  • Each academic year, the Department of Pharmacology and Chemical Biology, and the Department of Biochemistry and Molecular Biology host a joint off-site research conference where trainees present their work. (
  • Our research interests cover a broad spectrum of topics including chemical biology, drug delivery, drug discovery, computational biology, molecular genetics and genomics, protein design, protein structure, function and evolution and psychopharmacology. (
  • The Department of Pharmacology and Chemical Biology offers an advanced study program in pharmacology. (
  • See more information about the Graduate Program in Pharmacology and Chemical Biology . (
  • Molecular Biology and Evolution. (
  • The researchers speculate these chemical processes, now catalytically robust, evolved into separate pathways both in early plants and in their aquatic ancestors. (
  • One pathway--having chemical processes termed primary metabolism--allowed the production of life-sustaining chemicals. (
  • In the paper, the researchers hypothesize these secondary chemical processes arose from the more conserved, life-sustaining processes and term them 'specialized metabolism. (
  • For one, the first RNA molecules would have to arise by unguided, non-biological chemical processes. (
  • Chemical communication is mediated by signal production and signal perception and in house mice ( Mus musculus ), both processes involve lipocalin proteins (OBP, MUP, LCN) that transport volatiles and protect them in tissues where they are produced. (
  • 1] Interpretation of the chemical layers measured in ice cores requires knowledge of processes occurring after their deposition on the ice sheet. (
  • For the current papers, Emory collaborated with the research group of Martha Grover, a professor in the Georgia Tech School of Chemical & Biomolecular Engineering, to develop molecular models for the processes. (
  • This symposium will address the chemical and information processes involved in the creation of complex systems. (
  • These exciting discoveries in astrochemistry-a multidisciplinary field that focuses on the chemical composition of and processes in astrophysical and planetary environments-have potential applications to the general chemistry and chemical-engineering communities. (
  • Active systems, from cells and bacteria to flocks of birds, harvest chemical energy which they use to move and to control the complex processes needed for life. (
  • Among the sections are chapters dealing with prebiotic chemical processes and considering self-replication of polymers in mineral habitats. (
  • This perspective provides key concepts and current status of the research on the properties of nanocatalysts that influence the hydrogen evolution reaction. (
  • The formation and aging of organic aerosols (OA) proceed through multiple steps of chemical reaction and mass transport in the gas and particle phases, which is challenging for the interpretation of field measurements and laboratory experiments as well as accurate representation of OA evolution in atmospheric aerosol models. (
  • Formation and evolution of SOA is a complex process involving coupled chemical reaction and mass transport in the gas and particle phases. (
  • Sequential and parallel reaction pathways of oxidation and dimerization or oligomerization progressing along these corridors pass through characteristic regimes of reaction-, diffusion-, or accommodation-limited multiphase chemical kinetics that can be classified according to reaction location, degree of saturation, and extent of heterogeneity of gas and particle phases. (
  • The reaction mechanisms occurring at these electrodes are still not completely understood due to their complexity and localized character at the interfaces between different materials or between the gas atmosphere and the electrocatalyst, and need in situ techniques with very high chemical sensitivity, with the additional difficulty of probing the materials as close as possible to their realistic operating conditions. (
  • Accordingly, the simplest chemical ingredients and reaction conditions, such as those found on Earth millions of years ago on geothermal fields with subsoil volcanic activity or in shallow ponds for example, were sufficient to keep the synthesis of the RNA building blocks, going over a whole series of reaction steps. (
  • Such simple framework conditions, he concludes, made it all the more plausible that these reaction cascades and thus a decisive step in chemical evolution could have taken place on early Earth. (
  • Accordingly, the Chemical Sciences Roundtable of the National Academies of Sciences, Engineering, and Medicine held a workshop on November 8-9, 2018, to (1) explore the chemistry of space-its novel chemicals and reaction mechanisms, (2) discuss information from remote sensing through spectroscopy, and (3) consider discoveries from spacecraft missions in the solar system and laboratory studies of extraterrestrial samples. (
  • We have developed methods that allow us to carry out evolution in a continuous manner, within a single reaction mixture. (
  • In a chemical reaction one or more substances, called reactants undergo a chemical change to produce new substances called products of the reaction. (
  • Thus a chemical reaction is a process in which reactants undergo a change to produce products. (
  • One or more substances which react and undergo chemical change are called reactants of the chemical reaction. (
  • The new substances formed during the chemical reaction between the reactants are called products of the chemical reaction. (
  • A chemical reaction, in which the products formed react with each other to give back the original reactants, is called a reversible reaction. (
  • The reaction enthalpy of a chemical reaction is the enthalpy change that occurs when substances are transformed by a chemical reaction. (
  • The heat of reaction provides vital information regarding the start and end of the reaction, possible accumulation of reactants, the maximum heat evolution, the reaction kinetics, and the necessary reactor cooling capacity and kinetics. (
  • It produces a blue-coloured light by a specialized chemical reaction of the substrate luciferin and the enzyme luciferase. (
  • Theodoritsi, G. N. and Pandis, S. N.: Simulation of the chemical evolution of biomass burning organic aerosol, Atmos. (
  • Amitrano C, Peliti L, Saber M (1988) Neutralism and adaptation in a simple model of molecular evolution. (
  • Kimura M (1983) The neutral theory of molecular evolution. (
  • We continue both to advance the technology of directed molecular evolution and to seek novel applications for our evolved enzymes. (
  • In particular, statistical and mathematical models are a necessity for developing some sub-disciplines and theories like population genetics and ecology, neutral theory of molecular evolution and biodiversity, and machine-learning techniques for species distribution modeling. (
  • PROTEIN POWER Frances Arnold (left), George Smith (middle) and Gregory Winter (right) have won the 2018 Nobel Prize in chemistry for their work bringing evolution into the laboratory to design custom molecules. (
  • Plant secondary metabolism generates a huge diversity of chemicals that are not only very important to the plant, but also for humans,' said Greg Warr, a program manager in NSF's Division of Molecular & Cellular Biosciences. (
  • Chemical modification would be a key means to further increase their performance, e.g., expansion of function diversity, enhancement of activity, and improvement of biostability for biological use. (
  • As trans-AT PKSs incorporate unparalleled diversity in chemical space and naturally evolve by forming hybrid enzymes, harnessing their combinatorial potential presents an unprecedented opportunity for the discovery and engineering of new pharmaceutically-relevant chemical space. (
  • Our findings reveal that (i) type II polyketide structure is predictable from its gene roster, (ii) only certain gene combinations are compatible, and (iii) gene swaps were likely a key to evolution of chemical diversity. (
  • Design of multi-phase dynamic chemical networks" and "Catalytic diversity in self-propagating peptide assemblies. (
  • Many Ligularia species including L. fischeri were found to harbor high chemical diversity with geographic distributions. (
  • The results on them suggested that hybridization frequently occurs in Ligularia and that it is an important mechanism in the generation of chemical diversity. (
  • G protein-coupled receptors (GPCRs) form a class of biological chemical sensors with an enormous diversity in ligand binding and sensitivity. (
  • Genesis - In The Beginning deals with the origin and diversity of Life and early biological evolution and discusses the question of where (hot or cold sources) and when the beginning of Life took place. (
  • The Max Planck Institute for Chemical Ecology in Jena investigates the role, diversity and characteristics of chemical signals which control the interactions between organisms and their environment. (
  • However, Chemical Ecology concerns the developmental, behavioral and ecological consequences of chemical signals and goes beyond identification of natural compounds, or recordings of the neural responses they elicit. (
  • While many aspects of other chemical senses like taste and smell have been independently invented multiple times over the course of animal evolution, the chemical sense that detects these reactive compounds is different. (
  • The novel receptor mutants can be used to detect chemical ligands in complex mixtures and to discriminate among chemically or stereochemically related compounds. (
  • To this effect, plants have developed a wide range of chemical signalling compounds that enable them to optimise their adaptation to their respective environments. (
  • The tracers are sorted into three categories according to the evolution of their concentration: primary compounds, non-conventional primary compounds, and secondary compounds. (
  • Since the 20th century, there have been many exciting achievements in the field of ecology and evolution, many of which were formulated using statistical and mathematical functions. (
  • Amorphous molybdenum sulfide films are highly active hydrogen evolution catalysts, say researchers from Switzerland. (
  • With techniques such as XRD, TEM, DRS, XPS, N2 adsorption/desorption and electrochemistry measurements, the physicochemical properties of the [email protected] ternary composites are discussed, and a possible mechanism for the hydrogen evolution is proposed. (
  • The chemical composition, morphology, and the base sequence of the ITS regions in the rRNA gene were analyzed to identify F1 hybrids and introgressed individuals. (
  • Anderson PW (1983) Suggested model for prebiotic evolution: the use of chaos. (
  • The research was funded by the McDonnell Foundation, the National Science Foundation's Materials Science Directorate, Emory University's Alzheimer's Disease Research Center, the National Science Foundation's Center for Chemical Evolution and the Office of Basic Energy Sciences of the U.S. Department of Energy. (
  • Many evolutionists have now chosen to remain agnostic on the actual origin of life, and will frequently try to dodge the issue by claiming that abiogenesis is not part of the theory of evolution . (
  • This trend of bad luck continues for a collaborative team from the University of South Florida (USF) and the Georgia Institute of Technology (GT) who are seeking to identify a chemical process that could produce organic phosphates on early Earth, a necessary step in any origin-of-life scenario. (
  • Another problem origin-of-life researchers have identified with this chemical route relates to phosphates' solubility. (
  • Have modern origin-of-life theorists explained how this crucial bridge from inert nonliving chemicals to self-replicating molecular systems took place? (
  • Kuppers, Bernd-Olaf is the author of 'Molecular Theory of Evolution Outline of a Physico-Chemical Theory of the Origin of Life', published 0014 under ISBN 9780387155289 and ISBN 0387155287. (
  • The subject of this book is the physico-chemical theory of the origin of life. (
  • Textural and chemical features of the stage I crystals are consistent with a magmatic origin. (
  • Since amino acids are the smallest units of the protein molecule, Miller's experiment gave the molecular evolutionists great hope and encouragement for their idea of the chemical origin of life. (
  • To avoid the issue they often insist that the origin of life and biological evolution are separate issues. (
  • However, theory of evolution must (and does) include a theory of the origin of life , much as stellar evolution also postulates a mechanism for the birth of stars . (
  • The language connecting all living organisms is chemical - this section is devoted to chemical communication between plants, microorganisms and animals. (
  • Darwin's theory of evolution by natural selection is well-established - organisms adapt over time in response to environmental changes. (
  • Over many generations genetic codes of organisms can change significantly, resulting in the phenomenon of evolution. (
  • The organization of individual organisms into societies is one of the major transitions in evolution. (
  • This review focuses on the effectiveness of chemical modifications on the evolution of nucleic acids as functional molecules and the outlook for related technologies. (
  • Most in vitro evolution studies involve a powerful but laborious process in which a population of molecules is first challenged to perform a biochemical task, segregated on the basis of whether or not the molecules performed the task, and then amplified to produce "progeny" molecules that resemble but are not identical to their parents. (
  • These methods have helped explore the potential abilities of nucleic acids and steadily contributed to their evolution, i.e . , creation of RNA/DNA enzymes, aptamers, and aptazymes. (
  • Indeed, in the past two decades, random screening involving chemical modification, post-SELEX chemical modification, and rational design methods have been advanced, and combining and integrating these methods may produce a new class of functional nucleic acids. (
  • This is Part 2 of a 10-part series based upon Casey Luskin's chapter, " The Top Ten Scientific Problems with Biological and Chemical Evolution ," in the volume More than Myth , edited by Paul Brown and Robert Stackpole (Chartwell Press, 2014). (
  • Editor's Note: The following article is Casey Luskin's chapter, "The Top Ten Scientific Problems with Biological and Chemical Evolution," contributed to the volume More than Myth (Chartwell Press, 2014). (
  • It seems that almost on a daily basis, we find the news media quoting evolutionary scientists declaring that materialist accounts of biological and chemical evolution are "fact. (
  • Fitch WM, Markowitz E (1970) An improved method for determining codon variability in a gene and its application to the rate of fixation of mutations in evolution. (
  • After five rounds of evolution with screening of only 5500 clones, we obtained two strongly diverged haloalkane dehalogenase variants that give access to (R)-epichlorohydrin with 90 % ee and to (S)-epichlorohydrin with 97 % ee, containing 13 and 17 mutations, respectively, around their active sites. (
  • The resulting strain, which contains 11 gene overexpressions, 10 gene deletions by design, and more than 50 genomic mutations (including 3 global regulators) through evolution, grows aerobically in glucose minimal medium but can ferment anaerobically to products with nearly complete carbon conservation. (
  • Mutations are the basis of evolution as well as genetic disorders. (
  • Evolution depends on mutations because this is the only way that new alleles are formed. (
  • Some chemicals may increase the risk of mutations in the genes. (
  • Mutations are important in evolution as well. (
  • Are certain types of mutations fixed preferentially during adaptive evolution? (
  • Population genetics, pleiotropy, and the preferential fixation of mutations during adaptive evolution. (
  • Somatic evolution is the accumulation of mutations and epimutations in somatic cells (the cells of a body, as opposed to germplasm and stem cells ) during a lifetime, and the effects of those mutations and epimutations on the fitness of those cells. (
  • Since the discovery of the structure and function of olfactory receptors GPCRs-G-protein coupled receptors ( Buck and Axel, 1991 ), research on chemical communication has concentrated on signal reception by nasal and vomeronasal chemosensory neuronal receptors, and on lipocalin transporters of pheromones. (
  • That's how a new paper begins that proposes some provocative ideas about how plants developed the wide assortment of chemicals they use to sustain life and how they developed other chemicals that may or may not contribute to their immediate survival, but instead often ensure reproductive success in changing, earth environments. (
  • By utilizing the versatility of evolution-based enzyme design for large multifunctional proteins, one could generate an efficient, predictive, and adaptable engineering strategy for modular enzymes. (
  • After running the experiments and letting the chemical products sit for a period of time, Miller discovered that amino acids - the building blocks of proteins - had been produced. (
  • The origami of disease, and of life: Research into the abnormal folding of proteins related to neurodegenerative conditions is providing insights into how life may emerge from a chemical system. (
  • Olfactory physiology, from peripheral sensory perception to neuroethology, biochemistry and natural product chemistry make a substantial contribution to Chemical Ecology. (
  • Faraday Discussions document a long-established series of Faraday Discussion meetings which provide a unique international forum for the exchange of views and newly acquired results in developing areas of physical chemistry, biophysical chemistry and chemical physics. (
  • The editors wish to thank the European Science Foundation for its support of the programme on the Evolution of Chemistry in Europe, 1789-1939, as well as for sponsoring the publication of this volume. (
  • This is reflected in the contents of the three workshops dealing with the emergence of chemical industry held under the aegis of the European Science Foundation's Evolution of Chemistry in Europe, 1789-1939, programme. (
  • We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution, and export of NOx. (
  • 1 The ultimate goals of the workshop were to bring the various communities together to explore how discoveries in astrochemistry might provide insights or opportunities for the general chemistry and chemical-engineering communities and to promote understanding in the chemistry and chemical-engineering communities of how they might be able to help the astrochemistry community approach its challenges. (
  • Scientists from the fields of ecology, biochemistry, organic chemistry, entomology, ethology, and insect physiology work closely together in the Institute in order to understand the complex system of chemical communication. (
  • It is understood that the surface chemical composition deviates from the nominal bulk composition, and that secondary phases can segregate at the surfaces and interfaces during operation. (
  • Throughout the experiment we measure the fluid flow rate and chemical composition of the effluent fluid. (
  • 17 However, there are no known chemical or physical laws that dictate the order of those nucleotides. (
  • In the first paper we showed that you can create tension between a chemical and physical system to give rise to more complex systems. (
  • This protein misfolding provided the model for how physical changes could carry information with function, a critical component for evolution. (
  • To try to kickstart that evolution, the researchers engineered a chemical system of peptides and coupled it to the physical system of protein misfolding. (
  • Chemical and physical transformation of the biogenic elements from their nucleosynthesis in stars to their incorporation and subsequent modification in planetary bodies and terrestrial biochemistry. (
  • Proteolytic activity and physico-chemical characteristics were studied for Norwegian dry-cured ham at four different times of processing: raw hams, post-salted hams (3 months of processing), hams selected in the middle of the production (12 months of processing) and hams at the end of the processing (24 months). (
  • Attempts to harness the catalytic prowess of biosynthetic enzyme systems, for both compound discovery and engineering, have been limited by a poor understanding of the evolution of the underlying gene clusters. (
  • The chemical transport model PMCAMx was extended to investigate the effects of partitioning and photochemical aging of biomass burning emissions on organic aerosol (OA) concentrations. (
  • Positive matrix factorization of organic aerosol: insights from a chemical transport model A. Drosatou et al. (
  • The molecular corridors and kinetic regimes help to constrain and describe the properties of the products, pathways, and rates of SOA evolution, thereby facilitating the further development of aerosol models for air quality and climate. (
  • A thermal desorption aerosol gas chromatograph coupled to a high resolution - time of flight - aerosol mass spectrometer (TAG-AMS) was connected to an atmospheric chamber for the molecular characterization of the evolution of organic aerosol (OA) emitted by woodstove appliances for residential heating. (
  • Chemical communication is crucial for the maintenance of colony organization in eusocial insects and chemical signals are known to mediate important aspects of their social life, including the regulation of reproduction. (
  • Their research focuses on the co-evolution of plants and insects. (
  • Franziska Beran from the Max Planck Institute for Chemical Ecology in Jena now knows, however, how insects can avert this danger: flea beetles, for example, outsmart the plants' defensive weapon and even commandeer it for their own protection. (
  • Evolution, Chemical" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (
  • Plant-animal interaction is a continuing research focus, including the identification of chemicals that mediate food and host finding in herbivores. (
  • Such striking parallels indicate that specialist herbivores in marine and terrestrial systems can evolve convergent ecological strategies despite 400 million years of independent evolution in vastly different habitats. (
  • Marine-terrestrial contrasts in the ecology of plant chemical defenses against herbivores. (
  • Chemical defenses against different marine herbivores: are amphipods insect equivalents? (
  • Chemical dissimilarities were independent of differences in ovarian status in obligate eusocial species but were dependent on ovarian status in facultative eusocial species, which we discuss in an evolutionary framework. (
  • The Evolution & Genetics group has interests that encompass the ecological and evolutionary consequences of speciation and hybridisation to the evolution of social systems. (
  • The goal is to achieve an integrated, interdisciplinary understanding of the chemical, physiological and evolutionary principles that have shaped chemical communication across insect societies of different evolutionary and ecological history. (
  • Origins of Life and Evolution of Biospheres. (
  • High concentration of polymers shifted the chemical equilibrium towards the formation of stable polymers from unstable monomers. (
  • However, little is known about the evolution of odor signals at the transition from solitary living to eusociality. (
  • Here we investigated whether the dissimilarities in cuticle chemical signals in females of different castes and life stages reflect the level of social complexity across halictid bee species. (
  • We also tested whether social complexity was associated with a higher investment in chemical signals. (
  • Mate and habitat choice are to a large extent determined by chemical signals, and chemoreceptors contribute accordingly to premating isolation barriers and speciation. (
  • A windowed-differencing operation applied to chemical time series indicates a damping of the signals over the past 11,000 years, independent of minor climatic variation, for sulfate and chloride, but not sodium. (
  • As in many other insect-insect interactions, chemical signals are known or can be assumed to play an important role for the ability of the parasite to invade the host. (
  • Whenever you choke on acrid cigarette smoke, feel like you're burning up from a mouthful of wasabi-laced sushi, or cry while cutting raw onions and garlic, your response is being triggered by a primordial chemical sensor conserved across some 500 million years of animal evolution, report Brandeis scientists in a study in Nature this week. (
  • Studying the chemical sensors of Drosophila fruit flies, scientists discovered that flies use their ortholog of the human TRPA1 sensor for the same purpose. (
  • Understanding these nanoscale structural and chemical features will help scientists learn what characteristics make the inexpensive particles most effective-and devise ways to optimize their performance. (
  • The scientists used chemical-sensitive electron tomography, which is a nanoscale version of a CAT scan, to track what was happening structurally and chemically on the surface and inside the particles in 3D as they were oxidizing. (
  • Scientists around Professor Thomas Carell at the LMU Munich, are now able to explain another, if not the decisive, step in this chemical evolution that preceded biological phylogeny. (
  • What makes evolution such a profoundly provocative concept, so convincing to most scientists, yet so socially and politically divisive? (
  • The interior of the fruit fly proboscis contains sensors that detect pungent chemicals using a mechanism shared by sensors within the human mouth. (
  • These data suggest that module block recombination between different pathways is a major mechanism of chemical diversification for these enzymes. (
  • Microbial Chemical Ecology is now taking center stage, since interactions with bacteria, fungi or yeasts are widespread throughout the animal and plant kingdoms. (
  • Chemical cues regulate key ecological interactions in marine and terrestrial ecosystems. (
  • These gaps include their natural evolution, biochemical features (substrate specificity), structural features, protein-protein interactions/recognition, and protein dynamics. (
  • In November 2012, the Journal of Food and Chemical Toxicology published a paper titled Long Term Toxicity of Roundup Herbicide and a Roundup-Tolerant genetically modified maize by Gilles-Eric Séralini and his team of researchers at France's Caen University (source) . (
  • In a short video clip, Newman explains how ancient rock formations provide insights into the critical role that photosynthesizing bacteria played in the evolution of the Earth's atmosphere and modern life. (
  • We also demonstrate the effect of atmospheric aging on the chemical fingerprint. (
  • In a recently published article, we described the first example of "evolution on a chip," in which a population of RNA enzymes underwent 500 iterations of 10-fold exponential growth followed by 10-fold dilution, carried out during a period of 70 hours. (
  • We then used in vitro evolution to improve substantially the activity of the cross-replicating RNA enzymes. (
  • Based on molecular identification of SOA oxidation products, we show here that the chemical evolution of SOA from a variety of VOC precursors adheres to characteristic "molecular corridors" with a tight inverse correlation between volatility and molar mass. (
  • The other pathway produced chemicals that no longer carry life sustaining functions. (
  • Our hypothesis was that species with a higher social behavior ergo obligate eusocial species possess a more distinct chemical profile between castes or female life stages. (
  • Evolution has a history: Before life could be formed on the then still young planet, the first simple building blocks must have been created some four billion years ago that set its formation in motion. (
  • Charles Darwin's theory of organic evolution-the idea that life on earth is the product of purely natural causes, not the hand of God-set off shock waves that continue to reverberate through Western society, and especially the United States. (
  • A. Chemogeny (Chemical Evolution) B. Biogeny (Formation of Primitive Life) C. Cognogeny (Nature of Primitive Life and Its Evolution). (
  • We are applying the latest sequencing technologies to tackle ash dieback ( Buggs ), resolve ecological networks ( Clare ), understand the evolution of invertebrate nervous systems ( Elphick and Stollewerk ) and unlock the genetic basis of ageing in long-lived naked mole rats ( Faulkes ). (
  • This suggests that the earliest rocks should have contained an unusually large proportion of carbon of organic chemicals. (
  • Our results demonstrate the feasibility of altering receptor ligand-binding properties via a directed evolution strategy, using standard yeast genetic techniques. (
  • The genetic code undergoes several changes during the process of evolution. (
  • Evolution has been studied in various animals on the basis of genetic changes. (
  • While many of the genetic and epigenetic abnormalities in neoplasms are probably neutral evolution , many have been shown to increase the proliferation of the mutant cells, or decrease their rate of death ( apoptosis ). (
  • Modern descriptions of biological evolution will typically elaborate on major contributing factors to evolution such as the formation of local micro-environments, mutational robustness, molecular degeneracy , and cryptic genetic variation. (
  • The lessons learned about how natural selection drives polyketide chemical innovation can be applied to the rational design and guided discovery of chemicals with desired structures and properties. (
  • Using rational design, genome editing, and evolution, here we replaced the native glycolytic pathways in Escherichia coli with the previously designed nonoxidative glycolysis (NOG), which bypasses initial C3 formation and directly generates stoichiometric amounts of C2 metabolites. (
  • This project aims to reveal what chemical cues are involved in the evolution of nest parasitism and defence. (
  • This chapter will review some of this literature, and show that there are numerous legitimate scientific challenges to core tenets of Darwinian theory, as well as predominant theories of chemical evolution. (
  • The morphological evolution of the galaxies. (
  • The contents of this volume are based on the third of three workshops that have considered the emergence of the modern European chemical industry prior to 1939, the first held in Liege (1994), the second in Maastricht (1995), and the third in Strasbourg (1996). (
  • As the coronavirus crisis casts polystyrene and PS products in a more favorable light, chemical recycling could change the long-term sustainable equation for the polymer. (
  • Derivation of a Nonlinear Front Evolution Equation for Chemical Waves " by J. W. Wilder, Boyd F. Edwards et al. (
  • A nonlinear front evolution equation is derived using asymptotic analysis and is solved for an ascending front. (
  • Derivation of a nonlinear front evolution equation for chemicalwaves involving convection, J. W. Wilder, B. F. Edwards, D. A.Vasquez, and G. I. Sivashinsky, Physica D 73, 217 (1994) [14]. (
  • Consider the unbalanced chemical equation below: CaSiO3(s)+HF(g)CaF2(aq)+SiF4(g)+H2O(l) Suppose a 32.9-g sample. (
  • Bioluminescence: chemical principles and methods. (
  • Instead, these chemicals have more subtle effects on plants' fitness, or reproductive success in their local environments. (
  • Understanding how plants evolved their ability to synthesize secondary metabolites--such a vast and diverse array of chemicals--is a challenging problem,' said Parag Chitnis, director of NSF's Division of Molecular & Cellular Biosciences, which funded Noel's research. (
  • Assemblages of microbes, plants and animals are critical determinants of all ecosystems and depend on chemical communication. (
  • begingroup$ No addictive products produced by plants can be found to have exclusively detrimental effects on the plant, they all have mostly positive effects, and plants can minimize or maximize a single chemical at their disposal, over some dozens of generations, because it's only a single chemical. (
  • Chemical changes are the most usefual and evolutionarily cheap method for plants to ward off or attract animals, easier to adjust than color, shape, hairiness, stinging cells, size, and so on. (
  • Axel Mithöfer at the Max Planck Institute for Chemical Ecology in Jena is investigating how pitcher plants from Southeast Asia entrap and digest their victims. (
  • Even on cloudy days, the sun shines in the greenhouse of the Max Planck Institute for Chemical Ecology: 520 high-pressure lamps with assimilation sodium vapor bulbs ensure that the plants have sufficient light and that the spectral distribution is right for photosynthesis. (
  • These include various synthetic chemicals, particularly insecticides, as well as a variety of naturally occurring chemicals from plants, such as ethanol resulting from the fermentation of organic materials. (
  • The introduction of certain chemical substances-such as ethanol or pesticides or defensive toxic biochemicals produced by plants-to a bee's environment can cause the bee to display abnormal or unusual behavior and disorientation. (
  • Elysia sequester Halimeda's chemical defenses (to deter predators) and chloroplasts (becoming photosynthetic). (