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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Cholinesterases - Chromosome Banding
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Cholinergic neuron
Pertaining to neurons that use acetylcholine as neurotransmitter.
Cholinesterases
Enzyme that catalyse the hydrolysis of choline esters. Based on substrate specificity and susceptibility to inhibitors, there are two types –true cholinesterase and pseudocholinesterase. Both the enzymes are inhibited by alkalis and organic insecticides such as diisopropylfluorophosphate. Estimation of pseudo or type II cholinesterase in plasma is useful as a liver function test and also as an index of insecticide poisoning. Decreases activity of the enzymes is seen in various liver diseases such as acute and chronic hepatitis, cirrhosis and in liver metastases.
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Choluria
Presence of bile in the urine.
CHOmics
Global studies of carbohydrates.
Chondrocyte
Connective tissue cell that secretes the matrix of cartilage.
Chondroitin sulphate
A glycosaminoglycan. It is a polymer containing repeating units of α(1→3) linked disaccharides of glucuronic acid and N-acetylgalactosamine. The galactosamine is sulphated on the hydroxyl group of carbon 6.
Chorea
Unceasing, rapid, jerky involuntary movements.
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Chorionic villus sampling (CVS)
A procedure for obtaining a small sample of tissue from the placenta (chorionic villi) for prenatal diagnosis of genetic disorders. This is performed between 9 to 12 weeks of pregnancy.
Christmas factor
(antihaemophilic factor B, plasma thromboplastin component (PTC)) A clotting factor that activates factor that activates factor X in the intrinsic pathway.
Chromaffin Cell
A cell that stores epinephrine in vesicles and secretes it in response to stress.
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Chromatid
The copies of a chromosome generated by replication. The term is used to refer to the two chromatids when they are still joined at the centromere. When the centromere divides and the two chromatids separate (during anaphase of mitosis; and during anaphase II of meiosis), they are called chromosomes.
Chromatin
(Gr. chroma, colour). A nucleoprotein complex present in the nucleus at interphase. It is comprised of mainly DNA with some proteins (histones), and small amounts of RNA.
Chromatin assembly factors (CAFs)
Proteins that facilitate packaging of newly synthesised DNA with histones.
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Chromatin fibres
A basic organisational unit of eukaryotic chromosomes that consists of DNA and associated proteins assembled into strands of 30nm average diameter.
Chromatin immunoprecipitation (ChIP)
A method for the identification of proteins bound to particular sequences of DNA.
Chromatin remodeling
Energy-dependent displacement or reorganization of nucleosomes that takes place in conjunction with the activation of genes fro transcription.
Chromatofocusing
A technique suitable for protein separation. A linear pH gradient is generated in the column by exploiting the high buffer capacity of an ion exchanger preequilibrated to a particular pH.
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Chromat
Data file output from most popular DNA sequences that consist fluorescent traces generated by the sequencer for each of the four bases, A, C, G and T, together with the sequences and measures of the error in the traces at each sequence position.
Chromatography
(Gr. chroma, colour + graphein, meaning to draw or write). A technique for the separation and identification of molecules that are chemically similar the separation is based on partition and adsorption. It can be out on paper or in columns made of glass or metal. The term was originally used by Mikhail Tswett in 1906 to describe the separation of a mixture of leaf pigments on a calcium carbonate column.
Chromatosome
A nucleosomes core together with H 1.
Chromocenter
An aggregate of heterochromatin from different chromosomes.
Chromogenic label
A molecule attached to a probe that generates a coloured compound facilitating visualisation of the location and amount of probe bound to the target.
Chromogenic substrate
A substance that contains a colour-forming group.
Chromomeres
Small densely staining granular bodies, described by J. Belling, that are visible in chromosomes early in meiosis. They can be identified by their characteristic size linear arrangement along a chromosome.
Chromonema
(pl: chromonemata) A single thread forming an axial structure within each chromosome.
Chromophore
Any isolated covalently bonded group that shows a characteristic absorption in the ultraviolet or visible region (eg carbonyls, acids, esters).
Chromophore assisted laser inactivation
Antibodies specific for the targeted protein, but not neutralizing. These bring a reagent into proximity of the protein, and when activated by a laser, the reagent generates hydroxyl radicals that effectively inactivate protein.
Chromoplast
Plastid Containing pigments, such as chloroplast, or one in which Carotenoids predominate.
Chromosomal aberration
Abnormal structure or number of chromosomes. This includes loss, duplication, inversion, translocation, aneuploidy, or any other change from the normal pattern. Although it can enhance genetic diversity such alterations are usually fatal especially in animals.
Chromosomal deletion
The loss of part of a chromosomal DNA.
Chromosomal integration site
A site in he chromosome where the foreign DNA can be integrated without disrupting any essential function in the host organism.
Chromosomal inversion
Chromosome segments that have been turned by 180° as a result of which the gene sequences of the segment is reversed.
Chromosomal polymorphism
The occurrence of one to several chromosomes in two or more alternative structural forms within a population. The structurally changed chromosomes are the result of chromosomes mutations such as gain, loss or translocation of chromosomes segments.
Chromosomes
(Gr. chroma, colour + soma, body) 1. A single DNA molecule, condensed into a compact structure in vivo by complexing with proteins such as histones. 2. A group of nuclear bodies containing genes that plays an important role in the differentiation and activity of a eukaryotic cell. One of the structures into which he nucleus resolves itself at the beginning of mitosis, and from which it is derived at the end of mitosis.
Chromosomes contain most o the DNA of a cell. In eukaryotes, each species has a characteristic number of chromosomes, which are present in pairs-one paternal and the other maternal. Bacterial cells usually contain a single chromosomes made up of DNA. The viral chromosomes may contain DNA or RNA.
Chromosomes banding
Staining of chromosomes in such a way that light and dark areas are seen in repeated patterns along the length of the chromosomes. Each chromosome can be identified by its banding pattern.
Chromosomes condensation
Process by which a chromosome is packed into a more compact structure before M phase of the cell cycle.
Chromosome imbalance
A numerical chromosome disorder which may be deficiency or addition, causes by loss or gain of whole chromosomes (aneuploidy) or seats of chromosomes (polyploidy).
Chromosome jumping
A technique by which two segments of duplex DNA separated by thousands of base pairs (about 200 kb) can be cloned together. After subcloning, each segment can serve as probe as a probe for identifying cloned DNA sequences that are roughly 200 kb apart on the chromosomes. See positional cloning.
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