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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Gastritis - Gene Activator Protein
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Gastrin family
A family of gastrointestinal hormones grouped to gether based on the amino acid sequence and functional similarity. The members of the gastrin family include gastrin and cholecystokinin.
Gastrinoma
Gastrin-secreting tumours.
Gastritis
A group of disorders characterised by inflammation of the gastric mucosa.
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Based on the clinical features, there are two types of gastritis: acute gastritis, in which there is bleeding and loss of integrity of the gastric mucosa, and chronicgastritis, characterised by progressive destruction of the gastric of the gastric glands. Agents that injure the gastric mucosa include NSAIDs, ethanol and H.pylori.
Gastrojejunostomy
Establishing a communication between the stomach and the jejunum.
Gatekeeper genes
Genes that directly inhibit proliferation, induce apoptosis and promote terminal differentiation thereby controlling cell growth. Frequent mutations of these genes are observed in both sporadic and hereditary tumours.
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Gaucher disease
A lipid storage disease caused by a deficiency of β-glucocerebrosidase (β-glucosidase) that results in glucosylceramide lipidosis. Infantile, juvenile and adult forms have been recognised. Adult Gaucher is the most common lysosomal storage disease and is prevalent among Ashkenazi Jews with a frequency of 1 in 1000 births.
GC box
The sequence of nucleotides GGGCGG in the promoter region of mammalian genes that functions aa a binding site for certain transcription factors.
GC island
A GC-rich segment in DNA. This region often precedes a transcribed gene in vertebrate genomes.
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GDE
A flat file format for sequence data that is similar to FASTA.
GDP
Guanosine diphosphate. See guanosine.
Gel
A lyophilic colloid that has coagulated to a rigid or jelly-like solid. IT is used for the electrophoretic separation of nucleic acids or proteins, as well as for encapsulation. See encapsulating agent; gel electrophoresis.
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Gel electrophoresis
An analytical technique for the separation of charged molecules such as nucleic acids and proteins under the influence of an electric field. Samples are applied at one end of a slab of polymer gel and an electric field across the gel drives the molecules through it. While smaller molecules pass more easily and have greater mobility, larger molecules have lesser mobility. The migration of different molecules thus depends on the sized.
Gels that are used for electrophoresis include agarose, starch and polyacrylamide. Some chemicals can be included in the gel to help separation, such as the detergent sodium dodecyl sulphate (SDS) in protein gels to unfold proteins, or urea in DNA sequencing gels, which unfolds DNA. See isoelectric focussing gels; polyacrylamide gel electrophoresis (PAGE); pulsed field gel electrophoresis (PFGE).
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Gastrula
An early stage of the embryo that consists of two layers of cells. In this stage, the embryo is transformed from a ball of cells into a structure with a gut. This stage follows the blastula.
GC ratio
(percentage) The ratio of (G+C)/(A+T+G+C) of DNA expressed as percentage. The GC per cent can be determined from the melting point (Tm). This value is characteristic for each organism. Strains that differ in GC value by more than 10% are not phylogenetically related.
GC-rich regions
DNA sequences carrying long stretches of repeated GC bases indicate gene-rich regions.
Gastroenteritis
Inflammation of the stomach and intestine.
Gastroenteropathy
Disease of the stomach and intestine.
Gastroileostomy
Joining for the stomach to the ileum by surgery.
Gel filtration chromatography
The separation of molecules according to their size and shape through the use of cross-linked dextran or agarose beads.
Gel retardation
Slowing down of the electrophoretic mobility of a DNA fragment because of protein binding. Also known as gel shift or band shift.
Gel retardation assay
A technique based on the principle that nucleic acid-protein complexes move more slowly through an electrophoretic gel than unbound DNA. Labelled fragments of DNA or RNA are subjected to gel electrophoresis before and after incubation with a protein extract. A nucleic acid bound to protein moves more slowly than naked DNA due to gel retardation. The difference in band mobilities can be detected as a bandshift. This technique is useful for the identification and characterisation of protein-binding sites in DNA or RNA. Also called electrophoretic mobility shift assay, gelshift assay.
Gel transfer
The transfer of molecules separated by gel electrophoresis from the gel to a membrane for analysis; for example, Southern, Northern and Western blotting.
Gelation
A proteinaceous gelling and solidifying agent. It is produced by boiling animal connective tissues, which partially hydrolyses the collagen. It is used to gel or solidify nutrient solutions for tissue culture. See agar.
Gelatinization
Steam cooking of milled grain. This process increases the surface area of starch and converts the original mash to a substance with gel-like consistency.
GelriteTM The trade name of a Pseudomonas-derived refined polysaccharide that is used as a gelling agent and agar substitute.
Gelsolin
A protein that liquefies actin and filamin gels in presence of calcium by cleavage of actin filaments and capping of the cleaved filament ends.
GEM
Genetically engineered microorganism.
GenBand
A database of nucleic acid and protein sequences contributed by investigators around the world. It is maintained at the National Library of Medicine, USA and is divided into 13 sequence categories-primate, mammal, rodent, vertebrate, invertebrate, organelle, RNA, bacteria, plant, viral, bacteriophage, synthetic and annotated.
Gene
Conceptually, the unit of heredity that is transmitted during reproduction from one generation to the next. The term is used in a general sense to refer to the transmission and inheritance of particular identifiable characteristics (traits). In molecular terms, a gene is a segment of nucleic acid that encodes a peptides or RNA. See polygenes; dominant gene; fusion gene; gene expression; gene splicing; gene translocation; recessive gene; regulatory gene.
Gene activator protein
A gene regulatory protein which on binding to a regulatory sequence on DNA, activates transcription.
Gene addition
The addition of a functional copy of a gene to the genome of an organism.
Gene amplification
The generation of multiple copies of a particular gene without a proportional increase in other genes.
Gene bank
1. A population of organisms each of which carries a DNA molecule that was inserted into a cloning vector. Ideally, all of the cloned DNA molecules together represent the entire genome of another organism. Also called gene library, clone bank, bank library. 2. A collection of cloned DNA fragments from a single genome. 3. This term is sometimes also used to denote all of the vector molecules, each carrying a piece of chromosomal DNA of an organism, prior to the insertion of these molecules with a population of host cells. 4. The physical location where collections of genetic material in the form of seeds, tissues or reproductive cells of plats pr animals are stored. 5. Field gene bank: A facility developed for the ex situ storage and maintenance of individual plants, using horticultural techniques. It is generally used for species whose seeds are recalcitrant or for clonally propagated species of agricultural importance.
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