Monoterpenes: Compounds with a core of 10 carbons generally formed via the mevalonate pathway from the combination of 3,3-dimethylallyl pyrophosphate and isopentenyl pyrophosphate. They are cyclized and oxidized in a variety of ways. Due to the low molecular weight many of them exist in the form of essential oils (OILS, VOLATILE).Alkyl and Aryl Transferases: A somewhat heterogeneous class of enzymes that catalyze the transfer of alkyl or related groups (excluding methyl groups). EC 2.5.SesquiterpenesAgricultural Inoculants: Beneficial microorganisms (bacteria or fungi) encapsulated in carrier material and applied to the environment for remediation and enhancement of agricultural productivity.Picea: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are evergreen, pyramidal trees with whorled branches and thin, scaly bark. Each of the linear, spirally arranged leaves is jointed near the stem on a separate woody base.Abies: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. Balm of Gilead is a common name more often referring to POPULUS and sometimes to COMMIPHORA.Volatile Organic Compounds: Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.Ginkgo biloba: The only specie of the genus Ginkgo, family Ginkgoacea. It is the source of extracts of medicinal interest, especially Egb 761. Ginkgo may refer to the genus or species.Cinchona: A genus of rubiaceous South American trees that yields the toxic CINCHONA ALKALOIDS from their bark; QUININE; QUINIDINE; chinconine, cinchonidine and others are used to treat MALARIA and CARDIAC ARRHYTHMIAS.Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Polyisoprenyl Phosphates: Phosphoric or pyrophosphoric acid esters of polyisoprenoids.Weevils: BEETLES in the family Curculionidae and the largest family in the order COLEOPTERA. They have a markedly convex shape and many are considered pests.Intramolecular Lyases: Enzymes of the isomerase class that catalyze reactions in which a group can be regarded as eliminated from one part of a molecule, leaving a double bond, while remaining covalently attached to the molecule. (From Enzyme Nomenclature, 1992) EC 5.5.Oils, Volatile: Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.Wood: A product of hard secondary xylem composed of CELLULOSE, hemicellulose, and LIGNANS, that is under the bark of trees and shrubs. It is used in construction and as a source of CHARCOAL and many other products.Artemisia: A plant genus of the family ASTERACEAE with strong-smelling foliage. It is a source of SANTONIN and other cytotoxic TERPENES.Ginkgolides: DITERPENES with three LACTONES and a unique tert-butyl group, which are found in GINKGO plants along with BILOBALIDES.Diterpenes: Twenty-carbon compounds derived from MEVALONIC ACID or deoxyxylulose phosphate.Cyclohexenes: Six-carbon alicyclic hydrocarbons which contain one or more double bonds in the ring. The cyclohexadienes are not aromatic, in contrast to BENZOQUINONES which are sometimes called 2,5-cyclohexadiene-1,4-diones.Ocimum basilicum: A plant species of the genus OCIMUM, family LAMIACEAE. It is a condiment with carminative properties.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Skin Absorption: Uptake of substances through the SKIN.Farnesol: A colorless liquid extracted from oils of plants such as citronella, neroli, cyclamen, and tuberose. It is an intermediate step in the biological synthesis of cholesterol from mevalonic acid in vertebrates. It has a delicate odor and is used in perfumery. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Propylene Glycol: A clear, colorless, viscous organic solvent and diluent used in pharmaceutical preparations.Chamomile: Common name for several daisy-like plants (MATRICARIA; TRIPLEUROSPERMUM; ANTHEMIS; CHAMAEMELUM) native to Europe and Western Asia, now naturalized in the United States and Australia.Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Artemisia annua: A plant species of the genus ARTEMISIA, family ASTERACEAE. It is the source of the antimalarial artemisinin (ANTIMALARIALS).Actinidia: A plant species of the family ACTINIDIACEAE, order Theales.Carbon-Carbon Lyases: Enzymes that catalyze the cleavage of a carbon-carbon bond by means other than hydrolysis or oxidation. This subclass contains the DECARBOXYLASES, the ALDEHYDE-LYASES, and the OXO-ACID-LYASES. EC 4.1.Lactones: Cyclic esters of hydroxy carboxylic acids, containing a 1-oxacycloalkan-2-one structure. Large cyclic lactones of over a dozen atoms are MACROLIDES.Resins, Plant: Flammable, amorphous, vegetable products of secretion or disintegration, usually formed in special cavities of plants. They are generally insoluble in water and soluble in alcohol, carbon tetrachloride, ether, or volatile oils. They are fusible and have a conchoidal fracture. They are the oxidation or polymerization products of the terpenes, and are mixtures of aromatic acids and esters. Most are soft and sticky, but harden after exposure to cold. (From Grant & Hackh's Chemical Dictionary, 5th ed & Dorland, 28th ed)Pentanes: Five-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.Alstroemeria: A plant genus of the family LILIACEAE. Members contain allergens, tuliposide A and tulipalin A.Sesterterpenes: Terpenes of five units of HEMITERPENES, formed from geranylfarnesyl pyrophosphate.Sanguisorba: A plant genus of the family ROSACEAE. Members contain sanguiin.Pentanoic AcidsHemiterpenes: The five-carbon building blocks of TERPENES that derive from MEVALONIC ACID or deoxyxylulose phosphate.Dimethylallyltranstransferase: An enzyme that, in the pathway of cholesterol biosynthesis, catalyzes the condensation of isopentenyl pyrophosphate and dimethylallylpyrophosphate to yield pyrophosphate and geranylpyrophosphate. The enzyme then catalyzes the condensation of the latter compound with another molecule of isopentenyl pyrophosphate to yield pyrophosphate and farnesylpyrophosphate. EC A plant genus in the family ROSACEAE, order Rosales, subclass Rosidae. It is best known as a source of the edible fruit (apple) and is cultivated in temperate climates worldwide.Plant Components, Aerial: The above-ground plant without the roots.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Beta vulgaris: A species of the Beta genus. Cultivars are used as a source of beets (root) or chard (leaves).Cyclopentanes: A group of alicyclic hydrocarbons with the general formula R-C5H9.Plant Extracts: Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.Santalum: A plant genus of the family SANTALACEAE which is the source of sandalwood oil.Alkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Erythritol: A four-carbon sugar that is found in algae, fungi, and lichens. It is twice as sweet as sucrose and can be used as a coronary vasodilator.Chamaecyparis: A plant genus of the family CUPRESSACEAE which should not be confused with other cedar and cypress trees of THUJA or CUPRESSUS genera.Axenic Culture: Culture of an isolated organism free from any other associating or contaminating organisms.Pinus: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are evergreen trees mainly in temperate climates.Distillation: A chemical process for separating the components of a liquid mixture by boiling and collecting condensed vapors.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Oxylipins: Eighteen-carbon cyclopentyl polyunsaturated fatty acids derived from ALPHA-LINOLENIC ACID via an oxidative pathway analogous to the EICOSANOIDS in animals. Biosynthesis is inhibited by SALICYLATES. A key member, jasmonic acid of PLANTS, plays a similar role to ARACHIDONIC ACID in animals.Thuja: A plant genus of the family CUPRESSACEAE.Molecular Structure: 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.Biosynthetic Pathways: Sets of enzymatic reactions occurring in organisms and that form biochemicals by making new covalent bonds.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)BALB 3T3 Cells: Cell lines developed from disaggregated BALB/c mouse embryos. They are extremely sensitive to CONTACT INHIBITION, and highly susceptible to transformation by SV40 VIRUS and murine sarcoma virus (SARCOMA VIRUSES, MURINE).KetonesHexanes: Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.Flavonols: A group of 3-hydroxy-4-keto-FLAVONOIDS.Bicyclo CompoundsMolecular Sequence Data: 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.HydrocarbonsMenthol: An alcohol produced from mint oils or prepared synthetically.Diphosphates: Inorganic salts of phosphoric acid that contain two phosphate groups.SemicarbazonesBeetles: INSECTS of the order Coleoptera, containing over 350,000 species in 150 families. They possess hard bodies and their mouthparts are adapted for chewing.Administration, Cutaneous: The application of suitable drug dosage forms to the skin for either local or systemic effects.Flowers: The reproductive organs of plants.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Glycosides: Any compound that contains a constituent sugar, in which the hydroxyl group attached to the first carbon is substituted by an alcoholic, phenolic, or other group. They are named specifically for the sugar contained, such as glucoside (glucose), pentoside (pentose), fructoside (fructose), etc. Upon hydrolysis, a sugar and nonsugar component (aglycone) are formed. (From Dorland, 28th ed; From Miall's Dictionary of Chemistry, 5th ed)Plant Oils: Oils derived from plants or plant products.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Biocatalysis: The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.Alcohols: Alkyl compounds containing a hydroxyl group. They are classified according to relation of the carbon atom: primary alcohols, R-CH2OH; secondary alcohols, R2-CHOH; tertiary alcohols, R3-COH. (From Grant & Hackh's Chemical Dictionary, 5th ed)Food Preferences: The selection of one food over another.Amino Acid Sequence: 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.Isomerases: A class of enzymes that catalyze geometric or structural changes within a molecule to form a single product. The reactions do not involve a net change in the concentrations of compounds other than the substrate and the product.(from Dorland, 28th ed) EC 5.Chromatography, Gas: Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.Mevalonic AcidChemistry Techniques, Analytical: Methodologies used for the isolation, identification, detection, and quantitation of chemical substances.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Magnetic Resonance Spectroscopy: 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).Cloning, Molecular: 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.Multigene Family: 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)TriterpenesSequence Alignment: 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.Fruit: The fleshy or dry ripened ovary of a plant, enclosing the seed or seeds.Odors: The volatile portions of substances perceptible by the sense of smell. (Grant & Hackh's Chemical Dictionary, 5th ed)Trees: Woody, usually tall, perennial higher plants (Angiosperms, Gymnosperms, and some Pterophyta) having usually a main stem and numerous branches.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Biological Products: Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.Ozone: The unstable triatomic form of oxygen, O3. It is a powerful oxidant that is produced for various chemical and industrial uses. Its production is also catalyzed in the ATMOSPHERE by ULTRAVIOLET RAY irradiation of oxygen or other ozone precursors such as VOLATILE ORGANIC COMPOUNDS and NITROGEN OXIDES. About 90% of the ozone in the atmosphere exists in the stratosphere (STRATOSPHERIC OZONE).Medicago sativa: A plant species of the family FABACEAE widely cultivated for ANIMAL FEED.Transferases: Transferases are enzymes transferring a group, for example, the methyl group or a glycosyl group, from one compound (generally regarded as donor) to another compound (generally regarded as acceptor). The classification is based on the scheme "donor:acceptor group transferase". (Enzyme Nomenclature, 1992) EC 2.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Plastids: Self-replicating cytoplasmic organelles of plant and algal cells that contain pigments and may synthesize and accumulate various substances. PLASTID GENOMES are used in phylogenetic studies.Pyrophosphatases: A group of enzymes within the class EC 3.6.1.- that catalyze the hydrolysis of diphosphate bonds, chiefly in nucleoside di- and triphosphates. They may liberate either a mono- or diphosphate. EC 3.6.1.-.Ascomycota: A phylum of fungi which have cross-walls or septa in the mycelium. The perfect state is characterized by the formation of a saclike cell (ascus) containing ascospores. Most pathogenic fungi with a known perfect state belong to this phylum.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Chromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Mice, Hairless: Mutant strains of mice that produce little or no hair.Plant Roots: The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (From American Heritage Dictionary, 1982; Concise Dictionary of Biology, 1990)Genes, Plant: The functional hereditary units of PLANTS.Zea mays: A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Chemistry, Pharmaceutical: Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.Fungi: A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.Acetates: Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Fermentation: Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hordeum: A plant genus of the family POACEAE. The EDIBLE GRAIN, barley, is widely used as food.Molecular Conformation: The characteristic three-dimensional shape of a molecule.Plant Diseases: Diseases of plants.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Species Specificity: 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.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.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.Terpenes: A class of compounds composed of repeating 5-carbon units of HEMITERPENES.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cytochrome P-450 Enzyme System: A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.Catalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.Protein Structure, Secondary: 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.Mycobacterium: A genus of gram-positive, aerobic bacteria. Most species are free-living in soil and water, but the major habitat for some is the diseased tissue of warm-blooded hosts.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Escherichia coli: 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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Rumen: The first stomach of ruminants. It lies on the left side of the body, occupying the whole of the left side of the abdomen and even stretching across the median plane of the body to the right side. It is capacious, divided into an upper and a lower sac, each of which has a blind sac at its posterior extremity. The rumen is lined by mucous membrane containing no digestive glands, but mucus-secreting glands are present in large numbers. Coarse, partially chewed food is stored and churned in the rumen until the animal finds circumstances convenient for rumination. When this occurs, little balls of food are regurgitated through the esophagus into the mouth, and are subjected to a second more thorough mastication, swallowed, and passed on into other parts of the compound stomach. (From Black's Veterinary Dictionary, 17th ed)Sheep: Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.Conserved Sequence: 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.Animal Feed: Foodstuff used especially for domestic and laboratory animals, or livestock.Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Kinetics: The rate dynamics in chemical or physical systems.Bacterial Proteins: Proteins found in any species of bacterium.Structure-Activity Relationship: 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.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Genetic Variation: Genotypic differences observed among individuals in a population.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Oxidation-Reduction: 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).Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.