|
Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Basal Metabolic Rate BMR - Base Sequence Analysis
|
|
Bam islands Repeated sequences of fixed length in a nontranscribed spacer region. It is so called because these sequence were isolated by digestion with the restriction enzyme BamHI.
BamHI A restriction endonuclease that recognises the hexamer sequence 5’GGATCC3’ and cleaves it to generate sticky ends.
Bank See Gene Bank.
Bantu Siderosis An acquired Siderosis of dietary origin seen among Bantu tribes of Africa due to consumption of food high in corn, low in phosphate contain cooked in iron pots. The excess iron is deposited in hepatic parenchymal and teticuolendothelial cells.
|
Bar A unit used for the pressure of a fluid. 1 bar = 105 Pa and approximately equivalent to 1 atmosphere.
Bare lymphocyte syndrome An immune deficiency disorder resulting from a deficiency of some or all MHC molecules.
Barophile An organism that grows under conditions of high hydrostatic pressure such as the deep seas but is incapable of growing under normal atmospheric pressure.
Barotolerant An organism capable of tolerating high hydrostatic pressure.
|
Barr body A condensed mass of chromatin found in the nuclei of female mammals.
Barr body A condensed mass of chromatin found in the nuclei of female mammals.
It is a late-replicating, inactive X-chromosome named after its discoverer, Murray Barr.
Bartter’s syndrome A condition in which hyperplasia of the renal juxtaglomerular apparatus increases the secretion of rennin and consequently, aldosterone leading to increased urinary loss of potassium and hypokalaemia.
Basal Located near the base this is opposite to the apical surface.
Basal body A short cylindrical array of microtubules and associated proteins present at the base of the cilium of flagellum in a eukaryotic cell. It is similar in structure to a centriole and functions as a nucleation site for the growth of the Axoneme.
|
|
Basal lamina A this mat of extracellular matrix that separates epithelial sheets and other cell types from connective tissue.
Basal metabolic rate (BMR) Measurement of energy required to keep the body functioning at rest in calories. BMR increases with exertion, stress, fear, and illness and is influenced by thyroid hormones.
Basal transcription factors The minimal complement of proteins necessary to reconstitute accurate transcription from a minimal promoter such as TATA element or initiator sequence. They are distinct from the regulatory transcription factors, which bind to sequence farther away from the initiation site and serve to modulate levels of transcription. Assembly of the basal transcription complex involves an extensive series of protein-protein interactions.
Base 1. A proton acceptor.2 A heterocyclic, nitrogen –containing compound which is an essential component of nucleic acids. There are two major classes of bases-the purines (adenine, A; guanine, G) and the pyrimidines (thymine, T; cytosine, C; uracil, U).
|
|
|
Base analogues Molecules that resemble bases which form nucleotides that can be incorporated into a growing nucleotide chain (eg. Bromodeoxyyuacil). The base analogues exhibit aberrant base pairing properties and generate point mutations.
Base calling Determination of the base sequence in a DNA molecule from trace data.
Base excision repair A type of excision repair that repairs single base changes that occur due to deamination. Cytosine, adenine and guanine bases in DNA undergo deamination to form uracil, hypoxanthine and xanthine respectively.
|
These are recognised and removed by DNA glycosylases, generating apurinic apyrimidinic sites. The abasic sugar and phosphate are cleaved by an endonuclease.
The one – nucleotide gap is repaired by DNA pol I and sealed by ligase. The DNA glycosylases are specific for each type of lesion. For example, uracil DNA glycosylases remove uracil that results from spontaneous deamination of cytosine. While bacteria have a single uracil DNA glycosylases, at least four different enzymes have been recognised in humans.
Base Pair (bp) Hydrogen bonding between purines and pyrimidines in DNA. Adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C). The size of a nucleic acid molecule is described in terms of the number of base pairs or thousand base pairs (Kilobase pairs, kb).
Base sequence The order of nucleotide bases in a DNA molecule. The base sequence of DNA encodes the amino acid sequence of proteins.
Base sequence analysis A chemical or enzymatic method (often automated) for determining the base sequence.
Base stacking The close packing of the planes of base pairs in DNA and RNA.
Base substitution Replacement of one base with another base in a DNA molecule. See transition; transversion.
Basement membrane The membrane on which the epithelial cells rest. It contains the basal lamina together with a collagen –containing layer. The basal lamina is linked on one side to the cells by adhesion receptors and anchored on other side to the connective tissue by collagen fibers embedded in a proteoglycan-rich matrix.
Basic Possessing the properties of a base.
Basic amino acids Amino acids (lysine, arginine, histidine) whose side chains carry a positive charge at certain pH values.
Basic helix –loop-helix A structured motif in DNA –binding proteins. This motif is seen in some eukaryotic transcription factors.
Basic residue Amino acid side chains (lysine, arginine) that impart a positive charge to a protein at neutral pH.
Basket centrifuges Instruments that operate at very low centrifugal forces that are useful to collect proteins absorbed to ion-exchange supports.
Basolateral Refers to the base and side of a cell, organ or body structure. In epithelial cells, this surface abuts adjacent cells and the underlying basal lamina.
Basophil A Polymorphonuclear leukocyte, whose granules contain heparin, histamine and other vasoactive amines. Within tissues, these cells are known as mast cells.
Basophila An organism that thrives in alkaline environments.
Batch On a computer, refers to a job that is running in the background while the user is carrying out a different task.
Batch centrifuges Centrifuges that can accommodate solutions varying from less than 10ml to litres and can be operated at a wide range of centrifugal forces.
Batch culture See Batch fermentation
Batch fermentation A process in which cells or microorganisms are grown for a limited period of time. When the fermentation begins, an inoculum is introduced into fresh medium, with no further addition or removal of medium during the process.
Batch file A command file in a Windows environment. See command file.
Bathochromic shift Refers to a shift of the absorption maximum towards higher wavelength due to the presence of an auxochrome. This is also called the red shift. A decrease in polarity can also result in bathochromic shift.
Baum-Welch algorithm An expectation maximisation algorithm used to train Hidden Markov Models.
Bax A21 Da proapoptotic member of the Bcl-2 family. Bax is a cytosolic monomeric protein that shares extensive amino acid homology with Bcl-2. Several apoptotic stimuli induce translocation of Bax from the cytosol to the mitochondria thereby inducing cytochrome C release and facilitating apoptosis. During apoptosis, Bax translocates to the mitochondria and binds with another Bax or Bcl-2 molecule forming homodimers or heterodimers. Bax homodimers promote cytochrome C release whereas heterodimers inhibit the anti-apoptotic activity of Bcl-2. Down regulation of Bax is seen in a wide variety if tumours.
|
|
