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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Gradient Gels - Green Fluorescent Protein
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Gp120
A glycoprotein present on th surface of human immunodeficiency virus (HIV) During viral infection, th glycoprotein attaches to CD4, a receptor on th surface of the target lymphocyte. Antibodies against gp 120 epitopes are useful in developing anti-AIDS vaccines.
GPCR
See G-protein coupled receptors.
GPI anchor
See Glycosylphosphatidylinositol anchor.
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Gq
A class of receptor-coupled G protein that activates phospholipase C-β and initiates the phospholipid signaling pathway.
Gradient elution
In chromatography, refers to the use of a continuously changing eluting medium. For example if water is the initial solvent, and ethanol a stronger eluting agent, a solution of ethanol in water of gradually increasing strength is added to the agent, a solution of ethanol in water of gradually increasing strength is added to th column. This elutes more strongly absorbed substances and reduces tailing.
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Gradient gels
A polyacrylamide gel system in which the acrylamide concentration varies uniformly from 5% at the top of the gel to 25% at the bottom of the gel. The gradient is formed with the help of a gradient mixture. Gradient gels enables separation of proteins of a wide range of molecular weights as well as proteins of very similar molecular weight.
Graft rejection
An immune process that kills transplanted non-self tissue that is not histocompatible.
Graft vs. host reaction
An immune reaction mounted by lymphocytes in a graft tissue against the host tissues.
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Gram molecular weight
The weight in grams of a compound that is equal to its molecular weight. see mole.
Gram staining
A technique that helps to distinguish between two major bacterial groups, based on the retention of stain by their cell walls. Bacteria after heat fixation are stained with crystal violet, followed by iodine solution, rinsed with alcohol or acetone and counterstained with safranin O. Gram-positive bacteria stain bright purple, whereas Gram-negative bacteria are pink.
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Gramicidins
A class of polypeptide antibodies produced by Bacillus brevis. These function as ionophores and transport ions across the bacterial cell wall.
Gram-negative organism
A prokaryote that does not retain the first stain (crystal violet) but retains the second stain (Safranin O) during Gram staining. It therefore has a pink colour when viewed under a light microscope. Retention of the stain is due to the structure of the cell wall.
Gram-positive organism
A prokaryote that retains the first stain (crystal violet) used in Gram staining, giving a purple-blue colour when viewed under a light microscope. retention of crystal violet stain is due to the structure of the cell wall.
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Gram
A universal measure of mass that is defined as one thousandth of the mass of one litre of pure water at a temperature where its density is greatest, i.e. just above the freezing point.
GPCRomics
The study of the compilation of the complete catalog of human G-protein coupled receptors that present opportunities for therapeutic intervention and to efficiently identify small molecule modulators of these targets for drug development.
Grana
(singular: granum) Stacks of thylakoids, flattened membranous sacs or disks found in chloroplasts. They contain chlorophyll and carotenoid pigments that play a role in photosynthesis.
Granulocyte
One of three types of white blood cells that are responsible for destroying bacteria and other parasites. It is characterised by conspicuous cytoplasmic granules. Granulocytes include basophils, esinophils, and neutrophils. Also called polymorphonuclear leukocytes (PMNs).
Granulocyte macrophage-colony stimulating factor (GM-CSF)
A recombinant protein manufactured in large scale that is used as an adjunct to cancer chemotherapy. GM-CSF stimulates the production of granulocytes that enhance immunity.
Granulosa cells
The inner zone in the ovarian follicles that produces oestrogens and is regulated by FSH from the anterior pituitary.
Granzymes
Serine proteases located in the granules of cytotoxic T cell and NK cells that are involved in the induction of apoptosis. Now called fragments.
Graphical user interface (GUI)
Software that allows the user to interact via user friendly menu and mouse driven commands as opposed to ‘command line interface’ of typed or scripted commands. GUI is typical of Macintosh and Windows applications.
GRAS
See generally regarded as safe.
Gratuitous inducer
A substance capable of inducing transcription of a gene or genes, but is not a natural substrate for that enzyme(s). For example, isopropylthiogalactoside (IPTG) is a gratuitous inducer of β-galactosidase.
Graves’disease
The most common cause of hyperthyroidism in which thyroid hormone levels are increased and TSH release is suppressed. It occurs at any age and is more common among females. It is characterised by abnormal protrusion of the eyeballs (exophthalmos) due to swelling of the retroorbital tissues of the eyes and degenerative changes in the extraocular muscles impairing vision patients with Graves’disease have thyroid and thyroid stimulating immunoglobulins (TSI) such as long-acting thyroid stimulator (LATS).
Gray (Gy)
The does that given an energy absorption 1 JK-1. Gray is equal to 100 rad.
Gray crescent
A band of pale pigmentation seen in the egg of some species of amphibian opposite the sit of sperm entry following fertilisation that marks the future dorsal side. It is caused by the rotation of the egg cortex and associates pigment granules.
Gray matter
That portion of the spinal cord that is made up of nerve cell bodies in contrast to the white matter which is composed of axons and dendrites. The gray matter appears as a butterfly-shaped structure in cross section.
GRB2
An intermediate in the RTK-ras signal transduction pathway. While the SH2 domain of GRB2 binds to the phosphorylated cytoplasmic domain of an RTK, the SH3 domain binds to an SOS protein that stimulates CDP bound to ras to be exchanged for GTP.
GreA
A protein that releases E. coli RNA pol from elongation arrest together with GreB.
GreB
A protein that releases E. coli RNA pol from elongation arrest together with GreA.
Greek key
A complex supersecondary structure in proteins containing a four-strand antiparallel β-sheet where the four β-strands in the primary sequence 1-2-3-4 are arranged with the topology 4-1-2-3. This structure is found in many proteins with antiparallel β-sheets.
Green fluorescent protein (GFP)
A fluorescent protein isolated from a jellyfish that is used as a marker in cell biology and genetic engineering.
Green Revolution
The term given by William Goud to describe the dramatic increase in crop productivity during the third quarter of the 20th century that resulted from integrated advances in genetics and plant breeding, agronomy, and pest and disease control.
Gridded libraries
Clones from a library are picked and placed into individual well in multiwell plates. clones are spotted onto filters in a grid pattern with each grid assigned a precise reference coordinate. This technique reduces ambiguities in clone identification and permits gridded libraries to be transferred to other laboratories.
Griffith, Fredrick
(1881-1941) A bacteriologist who demonstrated that heat killed virulent pheumococcus bacteria is can transform live, nonpathogenic pneumococci to the pathogenic form.
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