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Channelrhodopsin-2
Channelrhodopsins are a subfamily of retinylidene proteins ( rhodopsins) that function as light-gated ion channels. They serve as sensory photoreceptors in unicellular green algae, controlling phototaxis: movement in response to light. Expressed in cells of other organisms, they enable light to control electrical excitability, intracellular acidity, calcium influx, and other cellular processes (see optogenetics). Channelrhodopsin-1 (ChR1) and Channelrhodopsin-2 (ChR2) from the model organism ''Chlamydomonas reinhardtii'' are the first discovered channelrhodopsins. Variants that are sensitive to different colors of light or selective for specific ions (ACRs, KCRs) have been cloned from other species of algae and protists. History Phototaxis and photoorientation of microalgae have been studied over more than hundred years in many laboratories worldwide. In 1980, Ken Foster developed the first consistent theory about the functionality of algal eyes. He also analyzed published act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-gated Ion Channel
Light-gated ion channels are a family of ion channels regulated by electromagnetic radiation. Other gating mechanisms for ion channels include voltage-gated ion channels, ligand-gated ion channels, mechanosensitive ion channels, and temperature-gated ion channels. Most light-gated ion channels have been synthesized in the laboratory for study, although two naturally occurring examples, channelrhodopsin and anion-conducting channelrhodopsin, are currently known. Photoreceptor proteins, which act in a similar manner to light-gated ion channels, are generally classified instead as G protein-coupled receptors. Mechanism Light-gated ion channels function in a similar manner to other gated ion channels. Such transmembrane proteins form pores through lipid bilayers to facilitate the passage of ions. These ions move from one side of the membrane to another under the influence of an electrochemical gradient. When exposed to a stimulus, a conformational change occurs in the transmembrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optogenetics
Optogenetics is a biological technique to control the activity of neurons or other cell types with light. This is achieved by expression of light-sensitive ion channels, pumps or enzymes specifically in the target cells. On the level of individual cells, light-activated enzymes and transcription factors allow precise control of biochemical signaling pathways. In systems neuroscience, the ability to control the activity of a genetically defined set of neurons has been used to understand their contribution to decision making, learning, fear memory, mating, addiction, feeding, and locomotion. In a first medical application of optogenetic technology, vision was partially restored in a blind patient. Optogenetic techniques have also been introduced to map the functional connectivity of the brain''.'' By altering the activity of genetically labelled neurons with light and using imaging and electrophysiology techniques to record the activity of other cells, researchers can identify ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Hegemann
Peter Hegemann (born 11 December 1954) is a Hertie Senior Research Chair for Neurosciences and a Professor of Experimental Biophysics at the Department of Biology, Faculty of Life Sciences, Humboldt University of Berlin, Germany. He is known for his discovery of channelrhodopsin, a type of ion channels regulated by light, thereby serving as a light sensor. This created the field of optogenetics, a technique that controls the activities of specific neurons by applying light. He has received numerous accolades, including the Rumford Prize, the Shaw Prize in Life Science and Medicine, and the Albert Lasker Award for Basic Medical Research. Early life and education Hegemann was born in Münster in 1954, but grew up in Aachen. Many in his immediate and extended family are doctors, including his parents, brother, and both grandfathers. He was educated in a humanities-oriented '' gymnasium'' (''humanistisches Gymnasium'') for secondary school, which he disliked for his lack of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phototaxis
Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite. Two types of positive phototaxis are observed in prokaryotes. The first is called scotophobotaxis (from the word " scotophobia"), which is observed only under a microscope. This occurs when a bacterium swims by chance out of the area illuminated by the microscope. Entering darkness signals the cell to reverse flagella rotation direction and reenter the light. The second type of phototaxis is true phototaxis, which is a directed movement up a gradient to an increasing amount of light. This is analogous to positive chemotaxis except that the attractant is light rather than a chem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phototaxis
Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite. Two types of positive phototaxis are observed in prokaryotes. The first is called scotophobotaxis (from the word " scotophobia"), which is observed only under a microscope. This occurs when a bacterium swims by chance out of the area illuminated by the microscope. Entering darkness signals the cell to reverse flagella rotation direction and reenter the light. The second type of phototaxis is true phototaxis, which is a directed movement up a gradient to an increasing amount of light. This is analogous to positive chemotaxis except that the attractant is light rather than a chem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GenBank
The GenBank sequence database is an open access, annotated collection of all publicly available nucleotide sequences and their protein translations. It is produced and maintained by the National Center for Biotechnology Information (NCBI; a part of the National Institutes of Health in the United States) as part of the International Nucleotide Sequence Database Collaboration (INSDC). GenBank and its collaborators receive sequences produced in laboratories throughout the world from more than 500,000 formally described species. The database started in 1982 by Walter Goad and Los Alamos National Laboratory. GenBank has become an important database for research in biological fields and has grown in recent years at an exponential rate by doubling roughly every 18 months. Release 250.0, published in June 2022, contained over 17 trillion nucleotide bases in more than 2,45 billion sequences. GenBank is built by direct submissions from individual laboratories, as well as from bulk submis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accession Number (bioinformatics)
An accession number, in bioinformatics, is a unique identifier given to a DNA or protein sequence record to allow for tracking of different versions of that sequence record and the associated sequence over time in a single data repository. Because of its relative stability, accession numbers can be utilized as foreign key A foreign key is a set of attributes in a table that refers to the primary key of another table. The foreign key links these two tables. Another way to put it: In the context of relational databases, a foreign key is a set of attributes subject to ...s for referring to a sequence object, but not necessarily to a unique sequence. All sequence information repositories implement the concept of "accession number" but might do so with subtle variations. LRG Locus Reference Genomic (LRG) records have unique accession numbers starting with LRG_ followed by a number. They are recommended in thHuman Genome Variation Society Nomenclature guidelinesas stable genomic ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenopus
''Xenopus'' () (Gk., ξενος, ''xenos''=strange, πους, ''pous''=foot, commonly known as the clawed frog) is a genus of highly aquatic frogs native to sub-Saharan Africa. Twenty species are currently described within it. The two best-known species of this genus are ''Xenopus laevis'' and ''Xenopus tropicalis'', which are commonly studied as model organisms for developmental biology, cell biology, toxicology, neuroscience and for modelling human disease and birth defects. The genus is also known for its polyploidy, with some species having up to 12 sets of chromosomes. Characteristics ''Xenopus laevis'' is a rather inactive creature. It is incredibly hardy and can live up to 15 years. At times the ponds that ''Xenopus laevis'' is found in dry up, compelling it, in the dry season, to burrow into the mud, leaving a tunnel for air. It may lie dormant for up to a year. If the pond dries up in the rainy season, ''Xenopus laevis'' may migrate long distances to another pond, main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HEK 293 Cells
Human embryonic kidney 293 cells, also often referred to as HEK 293, HEK-293, 293 cells, or less precisely as HEK cells, are a specific immortalised cell line derived from a spontaneously miscarried or aborted fetus or human embryonic kidney cells grown in tissue culture taken from a female fetus in 1973. HEK 293 cells have been widely used in cell biology research for many years, because of their reliable growth and propensity for transfection. They are also used by the biotechnology industry to produce therapeutic proteins and viruses for gene therapy as well as safety testing for a vast array of chemicals. 293T (or HEK 293T) is a derivative human cell line that expresses a mutant version of the SV40 large T antigen. It is very commonly used in biological research for making proteins and producing recombinant retroviruses. History HEK 293 cells were generated in 1973 by transfection of cultures of normal human embryonic kidney cells with sheared adenovirus 5 DNA in Alex v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromophore
A chromophore is the part of a molecule responsible for its color. The color that is seen by our eyes is the one not absorbed by the reflecting object within a certain wavelength spectrum of visible light. The chromophore is a region in the molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum. Visible light that hits the chromophore can thus be absorbed by exciting an electron from its ground state into an excited state. In biological molecules that serve to capture or detect light energy, the chromophore is the moiety that causes a conformational change in the molecule when hit by light. Conjugated pi-bond system chromophores Just like how two adjacent p-orbitals in a molecule will form a pi-bond, three or more adjacent p-orbitals in a molecule can form a conjugated pi-system. In a conjugated pi-system, electrons are able to capture certain photons as the electrons resonate along a certain distance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seven-transmembrane Protein
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related proteins that are cell surface receptors that detect molecules outside the cell and activate cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times. Text was copied from this source, which is available under Attribution 2.5 Generic (CC BY 2.5) license. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. G protein-coupled receptors are found only in eukaryotes, including yeast, choanoflagellates, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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