Fluorescence: The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Microscopy, Fluorescence: 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.Fluorescence Polarization: Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.In Situ Hybridization, Fluorescence: A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Fluorescence Resonance Energy Transfer: A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING.Fluorescence Recovery After Photobleaching: A method used to study the lateral movement of MEMBRANE PROTEINS and LIPIDS. A small area of a cell membrane is bleached by laser light and the amount of time necessary for unbleached fluorescent marker-tagged proteins to diffuse back into the bleached site is a measurement of the cell membrane's fluidity. The diffusion coefficient of a protein or lipid in the membrane can be calculated from the data. (From Segen, Current Med Talk, 1995).Microscopy, Fluorescence, Multiphoton: Fluorescence microscopy utilizing multiple low-energy photons to produce the excitation event of the fluorophore. Multiphoton microscopes have a simplified optical path in the emission side due to the lack of an emission pinhole, which is necessary with normal confocal microscopes. Ultimately this allows spatial isolation of the excitation event, enabling deeper imaging into optically thick tissue, while restricting photobleaching and phototoxicity to the area being imaged.Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.Green Fluorescent Proteins: 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.Energy Transfer: The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.Kinetics: The rate dynamics in chemical or physical systems.Rhodamines: A family of 3,6-di(substituted-amino)-9-benzoate derivatives of xanthene that are used as dyes and as indicators for various metals; also used as fluorescent tracers in histochemistry.Luminescent Proteins: 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.Fluoresceins: A family of spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one derivatives. These are used as dyes, as indicators for various metals, and as fluorescent labels in immunoassays.Carbocyanines: Compounds that contain three methine groups. They are frequently used as cationic dyes used for differential staining of biological materials.Microscopy, Confocal: 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.Fluorometry: An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS.Optical Imaging: The use of light interaction (scattering, absorption, and fluorescence) with biological tissue to obtain morphologically based information. It includes measuring inherent tissue optical properties such as scattering, absorption, and autofluorescence; or optical properties of exogenous targeted fluorescent molecular probes such as those used in optical MOLECULAR IMAGING, or nontargeted optical CONTRAST AGENTS.Photobleaching: Light-induced change in a chromophore, resulting in the loss of its absorption of light of a particular wave length. The photon energy causes a conformational change in the photoreceptor proteins affecting PHOTOTRANSDUCTION. This occurs naturally in the retina (ADAPTATION, OCULAR) on long exposure to bright light. Photobleaching presents problems when occurring in PHOTODYNAMIC THERAPY, and in FLUORESCENCE MICROSCOPY. On the other hand, this phenomenon is exploited in the technique, FLUORESCENCE RECOVERY AFTER PHOTOBLEACHING, allowing measurement of the movements of proteins and LIPIDS in the CELL MEMBRANE.Photons: Discrete concentrations of energy, apparently massless elementary particles, that move at the speed of light. They are the unit or quantum of electromagnetic radiation. Photons are emitted when electrons move from one energy state to another. (From Hawley's Condensed Chemical Dictionary, 11th ed)Protein Conformation: 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).Protein Binding: 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.Fluorescence Polarization Immunoassay: Fluoroimmunoassay where detection of the hapten-antibody reaction is based on measurement of the increased polarization of fluorescence-labeled hapten when it is combined with antibody. The assay is very useful for the measurement of small haptenic antigens such as drugs at low concentrations.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Anilino Naphthalenesulfonates: A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.Fluorescein: A phthalic indicator dye that appears yellow-green in normal tear film and bright green in a more alkaline medium such as the aqueous humor.2-Naphthylamine: A naphthalene derivative with carcinogenic action.Fluorescein-5-isothiocyanate: Fluorescent probe capable of being conjugated to tissue and proteins. It is used as a label in fluorescent antibody staining procedures as well as protein- and amino acid-binding techniques.Chlorophyll: Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Diffusion: The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.Lasers: An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.Acrylamide: A colorless, odorless, highly water soluble vinyl monomer formed from the hydration of acrylonitrile. It is primarily used in research laboratories for electrophoresis, chromatography, and electron microscopy and in the sewage and wastewater treatment industries.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Temperature: 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.Pyrenes: A group of condensed ring hydrocarbons.Dansyl Compounds: Compounds that contain a 1-dimethylaminonaphthalene-5-sulfonyl group.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Diphenylhexatriene: A fluorescent compound that emits light only in specific configurations in certain lipid media. It is used as a tool in the study of membrane lipids.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Molecular 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.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Naphthalenesulfonates: A class of organic compounds that contains a naphthalene moiety linked to a sulfonic acid salt or ester.PhotochemistryCell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Spectrometry, X-Ray Emission: The spectrometric analysis of fluorescent X-RAYS, i.e. X-rays emitted after bombarding matter with high energy particles such as PROTONS; ELECTRONS; or higher energy X-rays. Identification of ELEMENTS by this technique is based on the specific type of X-rays that are emitted which are characteristic of the specific elements in the material being analyzed. The characteristic X-rays are distinguished and/or quantified by either wavelength dispersive or energy dispersive methods.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Molecular Imaging: The use of molecularly targeted imaging probes to localize and/or monitor biochemical and cellular processes via various imaging modalities that include RADIONUCLIDE IMAGING; ULTRASONOGRAPHY; MAGNETIC RESONANCE IMAGING; FLUORESCENCE IMAGING; and MICROSCOPY.Staining and Labeling: The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.Liposomes: Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.Quantum Dots: Nanometer sized fragments of semiconductor crystalline material which emit PHOTONS. The wavelength is based on the quantum confinement size of the dot. They can be embedded in MICROBEADS for high throughput ANALYTICAL CHEMISTRY TECHNIQUES.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Biophysical Phenomena: The physical characteristics and processes of biological systems.Flow Cytometry: 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.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.Aminolevulinic Acid: A compound produced from succinyl-CoA and GLYCINE as an intermediate in heme synthesis. It is used as a PHOTOCHEMOTHERAPY for actinic KERATOSIS.Indocyanine Green: A tricarbocyanine dye that is used diagnostically in liver function tests and to determine blood volume and cardiac output.Thermodynamics: 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)Recombinant Fusion Proteins: 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.Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)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.Biosensing Techniques: Any of a variety of procedures which use biomolecular probes to measure the presence or concentration of biological molecules, biological structures, microorganisms, etc., by translating a biochemical interaction at the probe surface into a quantifiable physical signal.DNA: 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).Cell Line: Established cell cultures that have the potential to propagate indefinitely.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.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.Guanidine: A strong organic base existing primarily as guanidium ions at physiological pH. It is found in the urine as a normal product of protein metabolism. It is also used in laboratory research as a protein denaturant. (From Martindale, the Extra Pharmacopoeia, 30th ed and Merck Index, 12th ed) It is also used in the treatment of myasthenia and as a fluorescent probe in HPLC.Fluorescent Antibody Technique: Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.Membrane Fluidity: The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.Indicators and Reagents: Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)Cells, Cultured: 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.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Phosphatidylcholines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.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.4-Chloro-7-nitrobenzofurazan: A benzofuran derivative used as a protein reagent since the terminal N-NBD-protein conjugate possesses interesting fluorescence and spectral properties. It has also been used as a covalent inhibitor of both beef heart mitochondrial ATPase and bacterial ATPase.Protein Structure, Tertiary: 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.Cattle: 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.Molecular Probes: A group of atoms or molecules attached to other molecules or cellular structures and used in studying the properties of these molecules and structures. Radioactive DNA or RNA sequences are used in MOLECULAR GENETICS to detect the presence of a complementary sequence by NUCLEIC ACID HYBRIDIZATION.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.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.Protoporphyrins: Porphyrins with four methyl, two vinyl, and two propionic acid side chains attached to the pyrrole rings. Protoporphyrin IX occurs in hemoglobin, myoglobin, and most of the cytochromes.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Pyridinium CompoundsColoring Agents: Chemicals and substances that impart color including soluble dyes and insoluble pigments. They are used in INKS; PAINTS; and as INDICATORS AND REAGENTS.Photosensitizing Agents: Drugs that are pharmacologically inactive but when exposed to ultraviolet radiation or sunlight are converted to their active metabolite to produce a beneficial reaction affecting the diseased tissue. These compounds can be administered topically or systemically and have been used therapeutically to treat psoriasis and various types of neoplasms.Spectroscopy, Near-Infrared: A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.Laurates: Salts and esters of the 12-carbon saturated monocarboxylic acid--lauric acid.Boron Compounds: Inorganic or organic compounds that contain boron as an integral part of the molecule.Models, Biological: 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.Acrylamides: Colorless, odorless crystals that are used extensively in research laboratories for the preparation of polyacrylamide gels for electrophoresis and in organic synthesis, and polymerization. Some of its polymers are used in sewage and wastewater treatment, permanent press fabrics, and as soil conditioning agents.2-Aminopurine: A purine that is an isomer of ADENINE (6-aminopurine).Ethidium: A trypanocidal agent and possible antiviral agent that is widely used in experimental cell biology and biochemistry. Ethidium has several experimentally useful properties including binding to nucleic acids, noncompetitive inhibition of nicotinic acetylcholine receptors, and fluorescence among others. It is most commonly used as the bromide.Infrared Rays: That portion of the electromagnetic spectrum usually sensed as heat. Infrared wavelengths are longer than those of visible light, extending into the microwave frequencies. They are used therapeutically as heat, and also to warm food in restaurants.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Molecular Probe Techniques: The use of devices which use detector molecules to detect, investigate, or analyze other molecules, macromolecules, molecular aggregates, or organisms.Adenosine Triphosphate: 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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.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.Mutation: 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.Actins: 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.Calibration: Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.Photosystem II Protein Complex: A large multisubunit protein complex found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to catalyze the splitting of WATER into DIOXYGEN and of reducing equivalents of HYDROGEN.Tomography, Optical: Projection of near-IR light (INFRARED RAYS), in the 700-1000 nm region, across an object in parallel beams to an array of sensitive photodetectors. This is repeated at various angles and a mathematical reconstruction provides three dimensional MEDICAL IMAGING of tissues. Based on the relative transparency of tissues to this spectra, it has been used to monitor local oxygenation, brain and joints.Xanthenes: Compounds with three aromatic rings in linear arrangement with an OXYGEN in the center ring.Scattering, Radiation: The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Europium: Europium. An element of the rare earth family of metals. It has the atomic symbol Eu, atomic number 63, and atomic weight 152. Europium is used in the form of its salts as coatings for cathode ray tubes and in the form of its organic derivatives as shift reagents in NMR spectroscopy.Optical Phenomena: LIGHT, it's processes and properties, and the characteristics of materials interacting with it.Diagnostic Imaging: Any visual display of structural or functional patterns of organs or tissues for diagnostic evaluation. It includes measuring physiologic and metabolic responses to physical and chemical stimuli, as well as ultramicroscopy.Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.Chlortetracycline: A TETRACYCLINE with a 7-chloro substitution.Organic Chemicals: 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.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Microscopy: The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.Acridine Orange: A cationic cytochemical stain specific for cell nuclei, especially DNA. It is used as a supravital stain and in fluorescence cytochemistry. It may cause mutations in microorganisms.Molecular Conformation: The characteristic three-dimensional shape of a molecule.Light-Harvesting Protein Complexes: Complexes containing CHLOROPHYLL and other photosensitive molecules. They serve to capture energy in the form of PHOTONS and are generally found as components of the PHOTOSYSTEM I PROTEIN COMPLEX or the PHOTOSYSTEM II PROTEIN COMPLEX.Bacterial Proteins: Proteins found in any species of bacterium.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).Terbium: Terbium. An element of the rare earth family of metals. It has the atomic symbol Tb, atomic number 65, and atomic weight 158.92.Micelles: Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.DNA Probes: Species- or subspecies-specific DNA (including COMPLEMENTARY DNA; conserved genes, whole chromosomes, or whole genomes) used in hybridization studies in order to identify microorganisms, to measure DNA-DNA homologies, to group subspecies, etc. The DNA probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the DNA probe include the radioisotope labels 32P and 125I and the chemical label biotin. The use of DNA probes provides a specific, sensitive, rapid, and inexpensive replacement for cell culture techniques for diagnosing infections.Photosynthesis: The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.Quinolinium CompoundsColor: The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Optics and Photonics: A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.Cell Nucleus: 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)Optical Processes: Behavior of LIGHT and its interactions with itself and materials.Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Fura-2: A fluorescent calcium chelating agent which is used to study intracellular calcium in tissues.Image Cytometry: A technique encompassing morphometry, densitometry, neural networks, and expert systems that has numerous clinical and research applications and is particularly useful in anatomic pathology for the study of malignant lesions. The most common current application of image cytometry is for DNA analysis, followed by quantitation of immunohistochemical staining.Porphyrins: A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.Membrane Proteins: 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.Phospholipids: Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.Cell Line, Tumor: A cell line derived from cultured tumor cells.Photochemotherapy: Therapy using oral or topical photosensitizing agents with subsequent exposure to light.Eosine Yellowish-(YS): A versatile red dye used in cosmetics, pharmaceuticals, textiles, etc., and as tissue stain, vital stain, and counterstain with HEMATOXYLIN. It is also used in special culture media.Protein Transport: 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.Anisotropy: A physical property showing different values in relation to the direction in or along which the measurement is made. The physical property may be with regard to thermal or electric conductivity or light refraction. In crystallography, it describes crystals whose index of refraction varies with the direction of the incident light. It is also called acolotropy and colotropy. The opposite of anisotropy is isotropy wherein the same values characterize the object when measured along axes in all directions.Peptides: 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.Aneuploidy: The chromosomal constitution of cells which deviate from the normal by the addition or subtraction of CHROMOSOMES, chromosome pairs, or chromosome fragments. In a normally diploid cell (DIPLOIDY) the loss of a chromosome pair is termed nullisomy (symbol: 2N-2), the loss of a single chromosome is MONOSOMY (symbol: 2N-1), the addition of a chromosome pair is tetrasomy (symbol: 2N+2), the addition of a single chromosome is TRISOMY (symbol: 2N+1).Membranes, Artificial: Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.Equipment Design: Methods of creating machines and devices.Nanotechnology: The development and use of techniques to study physical phenomena and construct structures in the nanoscale size range or smaller.NAD: A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Silver: Silver. An element with the atomic symbol Ag, atomic number 47, and atomic weight 107.87. It is a soft metal that is used medically in surgical instruments, dental prostheses, and alloys. Long-continued use of silver salts can lead to a form of poisoning known as ARGYRIA.Oxazines: Six-membered heterocycles containing an oxygen and a nitrogen.Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Water: 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)Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Microscopy, Video: Microscopy in which television cameras are used to brighten magnified images that are otherwise too dark to be seen with the naked eye. It is used frequently in TELEPATHOLOGY.Unilamellar Liposomes: Single membrane vesicles, generally made of PHOSPHOLIPIDS.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Dextrans: A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.Luminescence: Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.Cysteine: A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.Nanoparticles: Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.Serum Albumin, Bovine: Serum albumin from cows, commonly used in in vitro biological studies. (From Stedman, 25th ed)Translocation, Genetic: A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.Protein Multimerization: The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Viscosity: The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Fluoroimmunoassay: The use of fluorescence spectrometry to obtain quantitative results for the FLUORESCENT ANTIBODY TECHNIQUE. One advantage over the other methods (e.g., radioimmunoassay) is its extreme sensitivity, with a detection limit on the order of tenths of microgram/liter.Models, Theoretical: 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.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.1,2-Dipalmitoylphosphatidylcholine: Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.Karyotyping: Mapping of the KARYOTYPE of a cell.Apoproteins: The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Transfection: 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.Coumarins: Synthetic or naturally occurring substances related to coumarin, the delta-lactone of coumarinic acid.Fiber Optic Technology: The technology of transmitting light over long distances through strands of glass or other transparent material.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.Potassium Iodide: An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Gene Amplification: A selective increase in the number of copies of a gene coding for a specific protein without a proportional increase in other genes. It occurs naturally via the excision of a copy of the repeating sequence from the chromosome and its extrachromosomal replication in a plasmid, or via the production of an RNA transcript of the entire repeating sequence of ribosomal RNA followed by the reverse transcription of the molecule to produce an additional copy of the original DNA sequence. Laboratory techniques have been introduced for inducing disproportional replication by unequal crossing over, uptake of DNA from lysed cells, or generation of extrachromosomal sequences from rolling circle replication.MaleimidesPhotochemical Processes: Chemical reactions effected by light.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Time-Lapse Imaging: Recording serial images of a process at regular intervals spaced out over a longer period of time than the time in which the recordings will be played back.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Tomography: Imaging methods that result in sharp images of objects located on a chosen plane and blurred images located above or below the plane.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)Genes, Reporter: 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.Proteins: 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.Optical Fibers: Thin strands of transparent material, usually glass, that are used for transmitting light waves over long distances.Equipment Failure Analysis: The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.Electrophoresis, Capillary: A highly-sensitive (in the picomolar range, which is 10,000-fold more sensitive than conventional electrophoresis) and efficient technique that allows separation of PROTEINS; NUCLEIC ACIDS; and CARBOHYDRATES. (Segen, Dictionary of Modern Medicine, 1992)Photosynthetic Reaction Center Complex Proteins: Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.

Stabilization of poly-L-lysine/DNA polyplexes for in vivo gene delivery to the liver. (1/5934)

We are developing a self-assembling non-viral in vivo gene delivery vehicle based on poly-l-lysine and plasmid DNA. We have characterized poly-l-lysines of different chain lengths for DNA condensation and strength of DNA binding. Poly-l-lysine chains >20 residues bound DNA efficiently in physiological saline, while shorter chains did not. Attachment of asialoorosomucoid to PLL increased the PLL chain length required for efficient DNA binding in saline and for efficient DNA condensation. By electron microscopy, poly-l-lysine/DNA polyplexes appeared as toroids 25-50 nm in diameter or rods 40-80 nm long; conjugation of asialoorosomucoid to the polylysine component increased the size of resulting polyplexes to 50-90 nm. In water, poly-l-lysine and asialoorosomucoid-PLL polyplexes have effective diameters of 46 and 87.6 nm, respectively. Polyplexes containing only poly-l-lysine and DNA aggregated in physiological saline at all charge ratios and aggregated at neutral charge ratios in water. Attachment of asialoorosomucoid lessened, but did not eliminate, the aggregation of PLL polyplexes, and did not result in efficient delivery of polyplexes to hepatocytes. Conjugation of polyethylene glycol to poly-l-lysine sterically stabilized resulting polyplexes at neutral charge ratios by shielding the surfaces. For efficient in vivo gene delivery, polyplexes will need to be sterically stabilized to prevent aggregation and interaction with serum components.  (+info)

Relocating the active site of activated protein C eliminates the need for its protein S cofactor. A fluorescence resonance energy transfer study. (2/5934)

The effect of replacing the gamma-carboxyglutamic acid domain of activated protein C (APC) with that of prothrombin on the topography of the membrane-bound enzyme was examined using fluorescence resonance energy transfer. The average distance of closest approach (assuming kappa2 = 2/3) between a fluorescein in the active site of the chimera and octadecylrhodamine at the membrane surface was 89 A, compared with 94 A for wild-type APC. The gamma-carboxyglutamic acid domain substitution therefore lowered and/or reoriented the active site, repositioning it close to the 84 A observed for the APC. protein S complex. Protein S enhances wild-type APC cleavage of factor Va at Arg306, but the inactivation rate of factor Va Leiden by the chimera alone is essentially equal to that by wild-type APC plus protein S. These data suggest that the activities of the chimera and of the APC.protein S complex are equivalent because the active site of the chimeric protein is already positioned near the optimal location above the membrane surface to cleave Arg306. Thus, one mechanism by which protein S regulates APC activity is by relocating its active site to the proper position above the membrane surface to optimize factor Va cleavage.  (+info)

Mitochondrial depolarization accompanies cytochrome c release during apoptosis in PC6 cells. (3/5934)

Cytochrome c is released from mitochondria into the cytosol in cells undergoing apoptosis. The temporal relationship between cytochrome c release and loss of mitochondrial membrane potential was monitored by laser-scanning confocal microscopy in single living pheochromocytoma-6 cells undergoing apoptosis induced by staurosporine. Mitochondrial membrane potential monitored by tetramethylrhodamine methyl ester decreased abruptly in individual cells from 2 to 7 h after treatment with staurosporine. Depolarization was accompanied by cytochrome c release documented by release of transfected green fluorescent protein-tagged cytochrome c in these cells. The results show that mitochondrial depolarization accompanies cytochrome c release in pheochromocytoma-6 cells undergoing apoptosis.  (+info)

Novel, highly lipophilic antioxidants readily diffuse across the blood-brain barrier and access intracellular sites. (4/5934)

In an accompanying article, an in vitro assay for permeability predicts that membrane-protective, antioxidant 2,4-diamino-pyrrolo[2, 3-d]pyrimidines should have improved blood-brain barrier (BBB) permeation over previously described lipophilic antioxidants. Using a first-pass extraction method and brain/plasma quantification, we show here that two of the pyrrolopyrimidines, one of which is markedly less permeable, readily partition into rat brain. The efficiency of extraction was dependent on serum protein binding, and in situ efflux confirms the in vitro data showing that PNU-87663 is retained in brain longer than PNU-89843. By exploiting inherent fluorescence properties of PNU-87663, its distribution within brain and within cells in culture was demonstrated using confocal scanning laser microscopy. PNU-87663 rapidly partitioned into the cell membrane and equilibrates with cytoplasmic compartments via passive diffusion. Although partitioning of PNU-87663 favors intracytoplasmic lipid storage droplets, the compound was readily exchangeable as shown by efflux of compound from cells to buffer when protein was present. The results demonstrated that pyrrolopyrimidines were well suited for quickly accessing target cells within the central nervous system as well as in other target tissues.  (+info)

A fluorescent orthotopic bone metastasis model of human prostate cancer. (5/5934)

Here, we report a fluorescent spontaneous bone metastatic model of human prostate cancer developed by surgical orthotopic implantation of green fluorescent protein (GFP)-expressing prostate cancer tissue. Human prostate cancer PC-3 cells were transduced with the pLEIN expression retroviral vector containing the enhanced GFP and neomycin resistance genes. Stable GFP high-expression PC-3 clones were selected in vitro with G418, which were then combined and injected s.c. in nude mice. For metastasis studies, fragments of a single highly fluorescent s.c. growing tumor were implanted by surgical orthotopic implantation in the prostate of a series of nude mice. Subsequent micrometastases and metastases were visualized by GFP fluorescence throughout the skeleton, including the skull, rib, pelvis, femur, and tibia The central nervous system, including the brain and spinal cord, was also involved with tumor, as visualized by GFP fluorescence. Systemic organs, including the lung, plural membrane, liver, kidney, and adrenal gland, also had fluorescent metastases. The metastasis pattern in this model reflects the bone and other metastatic sites of human prostate cancer. Thus, this model should be very useful for the study and development of treatment for metastatic androgen-independent prostate cancer.  (+info)

A sialoglycoprotein, gp20, of the human capacitated sperm surface is a homologue of the leukocyte CD52 antigen: analysis of the effect of anti-CD52 monoclonal antibody (CAMPATH-1) on capacitated spermatozoa. (6/5934)

In this study we performed N-terminal sequence analysis of gp20, a 20 kDa sialoglycoprotein on the human sperm surface previously identified by radiolabelling of the sialic acid residues of sperm surface. We found 100% identity with the N-terminus of CD52, an antigen expressed on almost all human leukocytes. We also show that, like CD52, gp20 behaves as a glycosylphosphatidylinositol (GPI)-anchored protein and that anti-gp20 antiserum reacts with an antigen on leukocytes of the same molecular weight as CD52. Using CAMPATH-1, the monoclonal antibody against CD52, in fluorescent staining of capacitated spermatozoa, Western blot analysis and the zona-free hamster egg penetration test, we found that the effect of this antibody was different from that of our anti-gp20. Western blot analysis revealed a well-defined 20 kDa band with anti-gp20, whereas a 14-20 kDa band was detected with CAMPATH-1. Anti-gp20 stained the equatorial region of the sperm head, whereas CAMPATH-1 stained the tail in immunofluorescence analysis of capacitated spermatozoa. A dose-dependent inhibitory effect was seen with CAMPATH-1, similar to that previously detected with anti-gp20, in a zona-free hamster egg penetration test. However, with CAMPATH-1 agglutination of motile spermatozoa was detected, and this was not present with anti-gp20. This suggests that the epitopes recognized by the two antibodies are different.  (+info)

Two affinities for a single antagonist at the neuronal NK1 tachykinin receptor: evidence from quantitation of receptor endocytosis. (7/5934)

1. In smooth muscle contractility assays, many NK1 receptor (NK1r) antagonists inhibit responses to the neurotransmitter, substance P (SP), and its analogue, septide, with markedly different potency, leading to the proposal that there is a septide-preferring receptor related to the NK1r. 2. We used fluorescence immunohistochemistry and confocal microscopy to visualize agonist-induced NK1r endocytosis and analyse agonist/antagonist interactions at native NK1r in neurons of the myenteric plexus of guinea-pig ileum. 3. SP and septide gave sigmoid log concentration-response curves and were equipotent in inducing NK1r endocytosis. 4. The NK1r antagonists, CP-99994 (2S,3S)-3-(2-methoxybenzyl)amino-2-phenylpiperidine dihydrochloride and MEN-10581, cyclo(Leu,[CH2NH]Lys(benzyloxycarbonyl)-Gln-Trp-Phe-betaAla) were both more potent in inhibiting endocytosis (50 x and 8 x greater respectively) against septide than against SP. 5. The results suggest that SP and septide interact differently with the NK1r, and that a single antagonist can exhibit different affinities at a single NK1r population, depending on the agonist with which it competes. Thus it may not be necessary to posit a separate septide-preferring tachykinin receptor.  (+info)

Simultaneous detection of multiple green fluorescent proteins in live cells by fluorescence lifetime imaging microscopy. (8/5934)

The green fluorescent protein (GFP) has proven to be an excellent fluorescent marker for protein expression and localisation in living cells [1] [2] [3] [4] [5]. Several mutant GFPs with distinct fluorescence excitation and emission spectra have been engineered for intended use in multi-labelling experiments [6] [7] [8] [9]. Discrimination of these co-expressed GFP variants by wavelength is hampered, however, by a high degree of spectral overlap, low quantum efficiencies and extinction coefficients [10], or rapid photobleaching [6]. Using fluorescence lifetime imaging microscopy (FLIM) [11] [12] [13] [14] [15] [16], four GFP variants were shown to have distinguishable fluorescence lifetimes. Among these was a new variant (YFP5) with spectral characteristics reminiscent of yellow fluorescent protein [8] and a comparatively long fluorescence lifetime. The fluorescence intensities of co-expressed spectrally similar GFP variants (either alone or as fusion proteins) were separated using lifetime images obtained with FLIM at a single excitation wavelength and using a single broad band emission filter. Fluorescence lifetime imaging opens up an additional spectroscopic dimension to wavelength through which novel GFP variants can be selected to extend the number of protein processes that can be imaged simultaneously in cells.  (+info)

  • Apex Market Reports, recently published a detailed market research study focused on the "Fluorescence Lifetime Imaging Microscopy Market" across the global, regional and country level. (openpr.com)
  • The report provides 360° analysis of "Fluorescence Lifetime Imaging Microscopy Market" from view of manufacturers, regions, product types and end industries. (openpr.com)
  • The research report analyses and provides the historical data along with current performance of the global PP Pipe industry, and estimates the future trend of Fluorescence Lifetime Imaging Microscopy on the basis of this detailed study. (openpr.com)
  • The study shares "Fluorescence Lifetime Imaging Microscopy" performance both in terms of volume and revenue. (openpr.com)
  • The market research report explores the Fluorescence Lifetime Imaging Microscopy Market across the globe along with major regions and countries. (openpr.com)
  • Moreover, the research study classifies the Fluorescence Lifetime Imaging Microscopy Market based on major product types, application and end users industries of Fluorescence Lifetime Imaging Microscopy. (openpr.com)
  • Besides, the report also covers geographical segmentation for Fluorescence Lifetime Imaging Microscopy Market. (openpr.com)
  • The competitive landscape of the global market for Fluorescence Lifetime Imaging Microscopy is determined by assessing the major industry participants, production capacity, production capacity utilization rate, Fluorescence Lifetime Imaging Microscopy Market's production chain, pricing by each manufacturer and the revenue generated by each manufacturer in the Fluorescence Lifetime Imaging Microscopy Market globally. (openpr.com)
  • The Global Fluorescence Lifetime Imaging Microscopy Market 2018 is further analyzed on the basis of product pricing, Fluorescence Lifetime Imaging Microscopy production volume, data pertaining to demand and Fluorescence Lifetime Imaging Microscopy supply, and the revenue garnered by the product. (openpr.com)
  • The report provides upstream and downstream analysis covering major raw material used in manufacturing of Fluorescence Lifetime Imaging Microscopy along with detailed manufacturing sources. (openpr.com)
  • Various methodical tools such as investment returns, feasibility, SWOT analysis and market attractiveness analysis has been implemented in the research study to present a comprehensive, detailed study of the industry for Fluorescence Lifetime Imaging Microscopy across the world. (openpr.com)
  • The Eclipse MicroTent™ is a unique product for fluorescence microscopy that provides local darkness around conventional laboratory stereo microscopes. (proscitech.com.au)
  • The phenomenon known as fluorescence is now widely used in the chemical and life sciences largely due to the development of highly sophisticated fluorescent probe chemistries and the commercial availability of these probes as well as the development of novel microscopy approaches. (iberlibro.com)
  • The long-pass filter has served well for most users who need to visualize green-fluorescent protein (GFP), and if you are exploring fluorescence in nature it is preferable. (proscitech.com.au)
  • Ghostly blue fluorescence spreads through a dying nematode worm, revealing the passage of death through its body. (medicalxpress.com)
  • Professor David Gems from the Institute of Health Ageing at UCL, who led the study, explains: "We've identified a chemical pathway of self-destruction that propagates cell death in worms, which we see as this glowing blue fluorescence travelling through the body. (medicalxpress.com)
  • The study, published online today in PLoS Biology , also links the mechanisms of cell death to the appearance of the blue fluorescence. (medicalxpress.com)
  • The source of the blue fluorescence was previously thought to be a substance called lipofuscin, which emits light of a similar colour and has been linked to ageing because it accumulates with increasing molecular damage. (medicalxpress.com)
  • He serves on the editorial boards of The Scientific World Journal, Analytical Biochemistry, and Methods and Applications in Fluorescence . (iberlibro.com)
  • He is a member of the advisory board for the Laboratory for Fluorescence Dynamics (supported by the National Institutes of Health) at the University of California, Irvine. (iberlibro.com)
  • Dr. Jameson's book fills a gap in the literature available for the student approaching the applications of fluorescence techniques as well as for the researcher practicing them daily in the laboratory setting. (iberlibro.com)
  • It introduces the fundamentals of the fluorescence phenomenon and gives detailed examples of fluorescence applications in the molecular life sciences, including biochemistry, biophysics, clinical chemistry and diagnostics, pharmaceutical science, and cell and molecular biology. (iberlibro.com)
  • The intrinsic or natural fluorescence of proteins is perhaps the most complex area of biochemical fluorescence. (springer.com)
  • In comparison, it has been easier to interpret the fluorescence data from labeled proteins because the fluorophore density and locations could be controlled so the probes did not interact with each other. (springer.com)
  • These two proteins present very similar UV absorption and fluorescence spectra. (springer.com)
  • Bimolecular fluorescence complementation (BiFC) is a recent technique used in the investigation and direct visualization of protein-protein interactions (PPIs) and interaction between proteins and other macro-molecules that are essential for survival of cells. (news-medical.net)
  • When these two proteins interact, both the segments re-associate resulting in re-formation of the fluorophore and fluorescence at the sites of interface. (news-medical.net)
  • Biophotonics techniques, especially those involving fluorescence, are widely used in proteomics to characterize the in vitro interactions between proteins in high-throughput mode. (nih.gov)
  • By labelling different proteins with fluorophores emitting at different wavelengths, spectrally-resolved fluorescence images can be used to provide information about temporal and spatial colocalisation of the different labelled proteins, which can provide insights into molecular processes. (imperial.ac.uk)
  • They found through a bootstrapping method that the pattern of fluorescence in the cells was heterogeneous to an extent that would be extremely unlikely by random chance, and showed using the Number and Brightness (N&B) technique that the degree of clustering of BiP on unfolded proteins under induced stress differed significantly from that in the homeostatic ER. (igert.org)
  • Now, you have a chance to win a free spot in one of our upcoming Intraoperative Fluorescence Workshops in 2018. (zeiss.com)
  • The field of fluorescence continues to grow steadily, both in fundamental aspects and applications in a highly interdisciplinary area (analytical, physical and organic chemistry, molecular sciences, biology, biomedicine and medical research. (springer.com)
  • Guiding readers from the basics to state-of-the-technology applications, this book is recommended for all chemists, physicists, and biomedical engineers working in the field of fluorescence. (wiley.com)
  • These aHL channels have been characterized using single-molecule fluorescence resonance energy transfer signals from vesicle-encapsulated guanine-rich DNA that folds in a G-quadruplex motif as well as from the Rep helicase-DNA system. (nih.gov)
  • The fluorescence emitted by the specimen is focused to the detector by the same objective that is used for the excitation which for greater resolution will need objective lens with higher numerical aperture. (wikipedia.org)
  • If the detector in a digital camera is off, for example, it may fail to collect fluorescence in some parts of the specimen, or could generate a false reading. (wisegeek.com)
  • Microfluidic integration on detector arrays for absorption and fluorescence micro-spectrometers", 2003, Journal of Scienctific Instruments, Elsevier Science, Sensors and Acturators A, vol. 104, pp.25-31. (freepatentsonline.com)
  • An ultra small fluorescence detector capable of detecting in real time reaction undergoing in a micro chamber having a predetermined volume and disposed on a microfluid chip is provided. (google.es)
  • Accordingly, the fluorescence detector is designed such that light emitted by a light source is focused between a first mirror and an objective lens. (google.es)
  • 2. The fluorescence detector of claim 1 , wherein the excitation beam is collected by the first lens so as to produce a focal point (F) in front of the objective lens. (google.es)
  • The basic idea was to find a silicon-based detector capable of demodulating fluorescence signals on a bi-dimensional array of pixels. (mdpi.com)
  • Light-induced damage to biological samples during fluorescence imaging is known to occur but receives too little attention by researchers. (nature.com)
  • A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. (hindawi.com)
  • Lumenera's INFINITY3 series cameras have proven to excel in fluorescence imaging - even under challenging conditions," said Eric Ramsden, Product Manager at Lumenera Corporation. (prweb.com)
  • NPs are promising candidates for fluorescence imaging and as nanothermometry agents. (nii.ac.jp)
  • This method has already been implemented by several universities and companies, and is proven to improve the reproducibility of wide-field fluorescence imaging . (nist.gov)
  • On the other hand, fluorescence-based imaging studies often show that protein activity is regulated through large protein complexes that transiently form at specific sites in the cell. (nih.gov)
  • Combined, the 1588 Advanced Imaging Modalities (AIM) Platform + SPY Fluorescence technology allow surgeons to visualize anatomy and blood flow during a variety of minimally invasive and open procedures. (stryker.com)
  • The SPY Portable Handheld Imager (SPY-PHI) utilizes SPY Fluorescence Imaging Technology, and allows surgeons to visualize blood flow in vessels and related tissue perfusion during plastic, microsurgical, reconstructive and gastrointestinal procedures. (stryker.com)
  • 1 With its sensitivity, specificity, noninvasiveness, and cost-effectiveness, fluorescence molecular imaging is widely applied in preclinical and clinical applications. (spiedigitallibrary.org)
  • The invention relates to a polarized light fluorescence imaging device comprising a structure of parallel microchannels ( 4 ) for containing the constituents to be analyzed. (freepatentsonline.com)
  • The scientists just published an article (" Fast fit-free analysis of fluorescence lifetime imaging via deep learning ") in the Proceedings of the National Academy of Sciences that described and demonstrated a new technique for fluorescence lifetime imaging of tissue and cells in a fast and comprehensive manner, thus laying the groundwork for use in a clinical setting. (genengnews.com)
  • The researchers' success brings the field closer to being able to use fluorescence lifetime imaging in a clinical setting in order to evaluate the effectiveness of a particular drug on a person's individual cancer cells, a key tool needed to enable precision medicine. (genengnews.com)
  • In the past, PTB has developed several approaches to detect rheumatoid alterations of finger joints by fluorescence imaging which were subsequently evaluated with clinical partners. (ptb.de)
  • Researchers in The Netherlands have demonstrated that combining SPECT/CT and fluorescence imaging could help surgeons differentiate tumor tissue from normal tissue. (innovations-report.com)
  • After resection of the thoracoabdominal wall, no tumor lesions were visible with the naked eye (C). Fluorescence imaging with the IVIS lumina closed cabinet fluorescence camera system could identify the superficially located tumor lesions (D). Fluorescence imaging with the Odyssey flatbed fluorescence scanner of the resected lungs could visualize numerous pulmonary lesions (E). L = lung, H = heart. (innovations-report.com)
  • This study shows that micrometastases of colorectal carcinoma can be detected specifically with fluorescence imaging and SPECT/CT before they become visible with the naked eye," says Marlène C.H. Hekman of the Department of Radiology and Nuclear Medicine at Radboudumc, Nijmegen, The Netherlands. (innovations-report.com)
  • Sub-millimeter pulmonary tumor colonies were visualized with both micro-SPECT and fluorescence imaging from the first week of tumor growth. (innovations-report.com)
  • She points out, "The study shows that SPECT and fluorescence dual-modality imaging after injection of Indium-111-DTPA-labetuzumab-IRDye800CW is able to detect tiny CEA-expressing nodules. (innovations-report.com)
  • Despite confounding factors, the fluorescence imaging system may provide a useful, objective, blinded system. (fluoridealert.org)
  • The fluorescence image signal features a third-order dependence on the excitation power, also providing intrinsic 3-D imaging. (spiedigitallibrary.org)
  • It was the summer of 2005 when in the laboratory of Fred Wouters we started the first autonomous runs of our new in-house developed high throughput fluorescence lifetime imaging (FLIM) system. (mdpi.com)
  • While additional research is required to sort out the subtleties of the fluorescence signal, the new maps are significant as they demonstrate the feasibility of measuring fluorescence from space. (redorbit.com)
  • The recorded fluorescence decay histogram obeys Poisson statistics which is considered in determining goodness of fit during fitting. (wikipedia.org)
  • The first FLIM experiments with biological samples were demonstrated using time-correlated single photon counting (TCSPC) 3 , which involves exciting the sample at sufficiently low excitation power such that the fluorescence photons can be detected one at a time and their arrival times recorded in a histogram that provides the fluorescence decay profile. (imperial.ac.uk)
  • Due to different molecular configurations of the emitters, multiple triplet states were detected and happen to drive one thermally activated delayed fluorescence (TADF) with very short lifetime of the order of nanoseconds. (nii.ac.jp)
  • In the rapidly expanding fields of cellular and molecular biology, widefield and confocal fluorescence illumination and observation is becoming one of the techniques of choice. (microscopyu.com)
  • Molecular oxygen (O 2 ) is an extremely efficient quencher of fluorescence just because of its unusual triplet ground state. (wikipedia.org)
  • Recent improvements in methods of single-particle fluorescence tracking have permitted detailed studies of molecular motion on the nanometer scale due to its high selectivity, sensitivity, simplicity, and fastness [ 8 ]. (hindawi.com)
  • Practical Uses Fluorescence is utilized in medicine, while phosphorescence is used for glow-in-the-dark products. (yahoo.com)
  • This allows to retreive the weak fluorescence signal, the glow that is emitted from the core oft he photosynthetic machinery. (fz-juelich.de)
  • A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. (google.ca)
  • A UV LED or other light source can be used to excite fluorescence from the edible oil samples. (oceanoptics.com)
  • These results demonstrate that FLI-Net is well suited to accurately quantify complex fluorescence lifetimes in cells and, in real time, in intact animals without any parameter settings. (genengnews.com)
  • Personally, I think people put WAY too much emphasis on diamond fluorescence. (pricescope.com)
  • The subject of diamond fluorescence has been hotly debated in recent years, with trade opinion divided regarding its effect on the appearance and value of diamonds. (77diamonds.com)
  • There are five levels of diamond fluorescence described by the GIA: None (i.e. no fluorescence), faint, medium, strong, very strong. (77diamonds.com)
  • 2. A biological fluorescence diagnostic apparatus according to claim 1, said path switching optical system selectively transmitting light passing through the ocular optical system of the endoscope to an image pickup surface of either of said two television cameras. (google.co.uk)
  • 3. A biological fluorescence diagnostic apparatus according to claim 2, said path switching optical system further comprising a reflecting optical system in which light passing through the ocular optical system along a first optical axis is reflected twice so as to travel in a direction having a second optical axis parallel to the first optical axis, whereby the optical axes of said two television cameras are disposed parallel to each other. (google.co.uk)
  • 4. A biological fluorescence diagnostic apparatus according to claim 2, wherein said path switching optical system comprises a roof-type reflecting member capable of being selectively inserted into and withdrawn from an optical path of light passing through the ocular optical system of the endoscope, wherein said roof-type reflecting member reflects an image such that right and left portions of said image are not interchanged. (google.co.uk)
  • As these processes are complementary processes analysis of chlorophyll fluorescence is an important tool in plant research with a wide spectra of applications. (wikipedia.org)
  • This variable rise in chlorophyll fluorescence rise is due to photosystem II. (wikipedia.org)
  • Heat dissipation cannot be totally stopped, so the yield of chlorophyll fluorescence in the absence of non-photochemical quenching cannot be measured. (wikipedia.org)
  • Chlorophyll fluorescence offers a more direct window into the inner workings of the photosynthetic machinery of plants from space. (redorbit.com)
  • With chlorophyll fluorescence, we should be able to tell immediately if plants are under environmental stress -- before outward signs of browning or yellowing of leaves become visible," said Elizabeth Middleton, a NASA Goddard-based biologist and a member of the team that created the maps. (redorbit.com)
  • The new findings help confirm previous lab and field experiments that suggest chlorophyll fluorescence should taper off in the fall as the abundance of green foliage declines and stress increases as a result of lower temperatures and less favorable light conditions. (redorbit.com)
  • Chlorophyll fluorescence from green foliage, for example, is produced at the red and far-red wavelengths. (redorbit.com)
  • Our X-Ray Fluorescence (XRF) Laboratory in Adelaide offers a range of analytical services on a fee for service basis on most mineral and plant samples. (www.csiro.au)
  • The application of X-Ray Fluorescence (XRF) to elemental analysis at the CSIRO Land and Water Adelaide Laboratory goes back to the early days of XRF spectrometry. (www.csiro.au)
  • By exploiting the experiences with the Xiralite imager, laboratory investigation shall help to optimize the fluorescence detection of the new system. (ptb.de)
  • Marketed sources equipped with polycapillary optics allow now laboratory X-Ray Fluorescence (XRF) analysis with 5-10 µm lateral resolution. (environmental-expert.com)
  • Despite the fact that fluorescence is used as an identifying characteristic rather than a grading factor in most laboratory quality reports, its presence in such reports is being used with increasing frequency to determine the pricing of a diamond. (77diamonds.com)
  • According to the GIA Gem Trade Laboratory, strength of fluorescence does not directly correlate to either colour or clarity. (77diamonds.com)
  • Particularly important to the future of science, in 1845 Herschel reported the first observation of the fluorescence of a quinine solution in sunlight. (fsu.edu)
  • 8. The device according to any of claims 1 , characterized in that the second means comprise a laser or microlaser for illuminating the whole of the microchannel structure ( 4 ) and in that the third means comprise a birefringent crystal ( 16 , 17 ) for separating the fluorescence light emitted according to two components polarized perpendicularly to each other. (freepatentsonline.com)
  • What is the difference between fluorescence and phosphorescence? (yahoo.com)
  • Phosphorescence is a specific type of photoluminescence related to fluorescence. (yahoo.com)
  • Phosphorescence is similar to fluorescence. (yahoo.com)
  • Glow-in-the-dark' light (phosphorescence) is not as bright as fluorescence but lasts much longer. (yahoo.com)
  • His work resulted in his introduction of what is now known as a Jablonski Energy Diagram , a tool that can be used to explain the kinetics and spectra of fluorescence, phosphorescence, and delayed fluorescence. (fsu.edu)
  • Phosphorescence - A fluorescence that persists after the bombarding radiation has ceased. (yahoo.com)
  • The analysis of major and trace elements in geological materials by x-ray fluorescence is made possible by the behavior of atoms when they interact with radiation. (carleton.edu)
  • Unlike fluorescence, a phosphorescent material does not immediately re-emit the radiation it absorbs. (yahoo.com)
  • Fluorescence occurs in some diamonds when they are exposed to the concentrated radiation of a UV lamp. (77diamonds.com)
  • Scientists from NASA's Goddard Space Flight Center in Greenbelt, Md., have produced groundbreaking global maps of land plant fluorescence, a difficult-to-detect reddish glow that leaves emit as a byproduct of photosynthesis. (redorbit.com)
  • Submicroscopic structures in the diamonds cause them to emit a visible light, a fluorescence, which is commonly blue in colour. (77diamonds.com)
  • We hypothesize that the areas of fluorescence represent areas of cellular activity within the pterygium. (nih.gov)