A state of internal activity of an organism that is a necessary condition before a given stimulus will elicit a class of responses; e.g., a certain level of hunger (drive) must be present before food will elicit an eating response.

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.

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.

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.

DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.

Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.

The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).

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.

Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.

Neurons which activate MUSCLE CELLS.

ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.

Recording of the changes in electric potential of muscle by means of surface or needle electrodes.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.

Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.

Elements of limited time intervals, contributing to particular results or situations.

Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.

Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.

Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.

The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.

The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.

The number of males per 100 females.

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.

Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.

Part of the brain located in the MEDULLA OBLONGATA and PONS. It receives neural, chemical and hormonal signals, and controls the rate and depth of respiratory movements of the DIAPHRAGM and other respiratory muscles.

Genes whose expression is easily detectable and therefore used to study promoter activity at many positions in a target genome. In recombinant DNA technology, these genes may be attached to a promoter region of interest.

Genes that are introduced into an organism using GENE TRANSFER TECHNIQUES.

The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).

A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.

All of the processes involved in increasing CELL NUMBER including CELL DIVISION.

The act of BREATHING in.

The legal authority or formal permission from authorities to carry on certain activities which by law or regulation require such permission. It may be applied to licensure of institutions as well as individuals.

The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.

A species of fruit fly much used in genetics because of the large size of its chromosomes.

A cell line derived from cultured tumor cells.

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.

Established cell cultures that have the potential to propagate indefinitely.

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.

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.

The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.

The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

The 12th cranial nerve. The hypoglossal nerve originates in the hypoglossal nucleus of the medulla and supplies motor innervation to all of the muscles of the tongue except the palatoglossus (which is supplied by the vagus). This nerve also contains proprioceptive afferents from the tongue muscles.

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 process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.

The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.

The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.

A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.

Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.

Use of electric potential or currents to elicit biological responses.

These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.

A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.

An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.

A transient absence of spontaneous respiration.

Computer-based representation of physical systems and phenomena such as chemical processes.

The parts of a macromolecule that directly participate in its specific combination with another molecule.

A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.

The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

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)

Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.

Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.

Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.

The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.

Neural tracts connecting one part of the nervous system with another.

A mechanism of communication with a physiological system for homeostasis, adaptation, etc. Physiological feedback is mediated through extensive feedback mechanisms that use physiological cues as feedback loop signals to control other systems.

Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.

Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.

The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.

Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.

A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.

Proteins that are involved in or cause CELL MOVEMENT such as the rotary structures (flagellar motor) or the structures whose movement is directed along cytoskeletal filaments (MYOSIN; KINESIN; and DYNEIN motor families).

The function of opposing or restraining the excitation of neurons or their target excitable cells.

RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.

Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.

A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.

The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.

Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.

The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.

Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.

Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.

Refers to animals in the period of time just after birth.

The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.

Cis-acting DNA sequences which can increase transcription of genes. Enhancers can usually function in either orientation and at various distances from a promoter.

The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.

The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.

The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.

Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).

The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.

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 pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.

A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.

The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.

Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.

A microtubule-associated mechanical adenosine triphosphatase, that uses the energy of ATP hydrolysis to move organelles along microtubules toward the plus end of the microtubule. The protein is found in squid axoplasm, optic lobes, and in bovine brain. Bovine kinesin is a heterotetramer composed of two heavy (120 kDa) and two light (62 kDa) chains. EC 3.6.1.-.

The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.

The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.

A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.

The functional hereditary units of INSECTS.

An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.

The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.

The relationships of groups of organisms as reflected by their genetic makeup.

The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.

A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.

A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.

Depolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during neurotransmission. Excitatory postsynaptic potentials can singly or in summation reach the trigger threshold for ACTION POTENTIALS.

Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.

The subfamily of myosin proteins that are commonly found in muscle fibers. Myosin II is also involved a diverse array of cellular functions including cell division, transport within the GOLGI APPARATUS, and maintaining MICROVILLI structure.

Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.

The rate dynamics in chemical or physical systems.

Proteins found in any species of bacterium.

Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.

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)

The observable response an animal makes to any situation.

A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.

The quality of surface form or outline of CELLS.

Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.

The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.

Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.

The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.

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 part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.

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.

A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.

A muscular organ in the mouth that is covered with pink tissue called mucosa, tiny bumps called papillae, and thousands of taste buds. The tongue is anchored to the mouth and is vital for chewing, swallowing, and for speech.

An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.

Inbred BALB/c mice are a strain of laboratory mice that have been selectively bred to be genetically identical to each other, making them useful for scientific research and experiments due to their consistent genetic background and predictable responses to various stimuli or treatments.

Histochemical localization of immunoreactive substances using labeled antibodies as reagents.

The properties, processes, and behavior of biological systems under the action of mechanical forces.

Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in neoplastic tissue.

Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.

The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.

Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.

Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.

Biological actions and events that support the functions of the RESPIRATORY SYSTEM.

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).

'Nerve tissue proteins' are specialized proteins found within the nervous system's biological tissue, including neurofilaments, neuronal cytoskeletal proteins, and neural cell adhesion molecules, which facilitate structural support, intracellular communication, and synaptic connectivity essential for proper neurological function.

A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.

Sexual activities of animals.

The spread of response if stimulation is prolonged. (Campbell's Psychiatric Dictionary, 8th ed.)

DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.

The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)

An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.

Genotypic differences observed among individuals in a population.

A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.

Specialized cells of the hematopoietic system that have branch-like extensions. They are found throughout the lymphatic system, and in non-lymphoid tissues such as SKIN and the epithelia of the intestinal, respiratory, and reproductive tracts. They trap and process ANTIGENS, and present them to T-CELLS, thereby stimulating CELL-MEDIATED IMMUNITY. They are different from the non-hematopoietic FOLLICULAR DENDRITIC CELLS, which have a similar morphology and immune system function, but with respect to humoral immunity (ANTIBODY PRODUCTION).

Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.

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).

A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.

Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.

Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.

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.

Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.

New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.

A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.

A dynamic actin-rich extension of the surface of an animal cell used for locomotion or prehension of food.

The total process by which organisms produce offspring. (Stedman, 25th ed)

The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.

The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.

A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.

An activity in which the body is propelled through water by specific movement of the arms and/or the legs. Swimming as propulsion through water by the movement of limbs, tail, or fins of animals is often studied as a form of PHYSICAL EXERTION or endurance.

Changes in biological features that help an organism cope with its ENVIRONMENT. These changes include physiological (ADAPTATION, PHYSIOLOGICAL), phenotypic and genetic changes.

A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.

The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.

The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).

Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).

Transport proteins that carry specific substances in the blood or across cell membranes.

The processes whereby the internal environment of an organism tends to remain balanced and stable.

The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.

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 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.

Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.

Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.

A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.

One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.

Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.

A family of DNA-binding transcription factors that contain a basic HELIX-LOOP-HELIX MOTIF.

The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.

Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.

The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.

Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.

Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.

Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.

Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.

A technique of culturing mixed cell types in vitro to allow their synergistic or antagonistic interactions, such as on CELL DIFFERENTIATION or APOPTOSIS. Coculture can be of different types of cells, tissues, or organs from normal or disease states.

A protein complex of actin and MYOSINS occurring in muscle. It is the essential contractile substance of muscle.

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.

A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)

Nucleic acid sequences involved in regulating the expression of genes.

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.

Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.

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.

Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.

A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.

The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.

The tubular and cavernous organs and structures, by means of which pulmonary ventilation and gas exchange between ambient air and the blood are brought about.

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.