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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Binary Vector System - Bioaccumulation
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Beta (β)-lipotrophin A molecule formed from pro-opiomelanocortin together with ACTH. It is activated by conversion to endorphins, which have neurotransmitter action.
Beta (β)-mercaptoethanol A reducing agent that breaks disulphide bonds in proteins.
Beta(β2)-microglobulin (BMG) See β2-microglobulin.
Beta (β)-oxidation Oxidative degradation of fatty acids by successive oxidation of the β-carbon atom of form acetyl CoA.
Beta (β)-alpha –(α)-beta(β) motif See β-α-β motif.
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Bibliomics A subset of high quality and rare information, retrieved and organised by systematic literature –searching tools from existing databases.
Bidirectional replication Replication that occurs by the movement of two replication forks away from the origin.
Bifunctional vector See Shuttle vector.
Biguanides Oral hypoglycaemic agents such as metformin and phenformin that decrease plasma glucose levels by inhibiting intestinal glucose absorption, TCA cycle and gluconeogenesis. These may however produce lactic acidosis.
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Bilayer A double layer of amphipathic lipids in which the hydrophilic (polar) ends are oriented outward in contact with water and the hydrophobic (nonpolar) ends are oriented inward facing each other forming a continuous hydrophobic core. The lipid bilayer forms the basic structure of biological membranes.
Bile Secretion of the parenchymal cells of the liver. Approximately 1 litre of bile is secreted per day into the bile canaliculi. Bile secreted from the hepatocytes passes through the intrahepatic ducts and enters the intestine through the common bile duct. The gallbladder concentrates the bile by absorption of water and electrolytes.
The components of bile include bile acids present as bile salts, bile pigments, cholesterol, lecithin, electrolytes, fatty acids and alkaline phosphatase.
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The functions of bile include fat absorption by bile salts which lower the surface tension and emulsify fats in the intestine, neutralization of acidic chime from the stomach and excretion of bile acids, bile pigments, cholesterol, drugs and toxins.
Bile acids Components of bile produced in the liver. These include cholic acid and chenodeoxycholic acid referred to as primary bile acids. Deoxycholic acid and lithocholic acid, which are products of the primary bile acids are known as secondary bile acids. In the liver, conjugation of bile acids occurs to form glycocholic acid and taurocholic acid, which form water-soluble sodium and potassium salts.
Bile salts Derivatives of cholesterol which have detergent properties. They help in the digestion and absorption of lipids.
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Binary vector system A two –plasmid system in Agrobacterium tumefaciens that is used for transferring a segment of T-DNA that carries cloned genes into plant cells. One of the plasmids contains the virulence gen (for transfer of T-DNA), whereas the other plasmid contains the T-DNA borders, the selectable marker and the DNA to be transferred.
BIND (Biomolecular Interaction Network Database) A database that provides functional annotations of proteins on the basis of their interactions with each other and with other ligands.
Binding The ability of molecules to stick to each other due to the shape and chemical nature of their surfaces. Many biological molecules bind very tightly and specifically to other molecules. For example, enzymes to their substrates; antibodies to their antigens; and DNA strands to their complementary strands. Binding is characterized by a binding constant or association constant (Ka).or it inverse, the dissociation constant(Kd).
Binding energy The energy obtained from the noncovalent interactions between an enzyme and its substrate or a receptor and its ligand.
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Bilirubin The product formed by the catabolism of haemoglobin in the reticuloendothelial cells. The globin portion of haemoglobin is degraded to form amino acids, which are reutilized. The haem moiety breaks down to iron and porphyrin. Iron is reutilized and porphyrin is converted to biliverdin, which is reduced to bilirubin. Bilirubin formed in the reticuloendothelial system is transported to the liver for conjugation and excreted via bile. Being water-insoluble, bilirubin is carried in the plasma bound to albumin.
Beta (β)-sheet A sheet –like structure formed by the interaction between two or more extended polypeptide chains.
Binding site The pocket or crevice in a protein that is bound by a ligand.
Binomial distribution The probability distribution expressing the probability of one set of dichotomous alternatives such as success of failure.
Bio A prefix derived from bios and used in scientific terminology in association with living organisms.
Bioaccumulation In an organism, the concentrations of substances that are not critical for survival of that organism. Generally, it refers to the accumulation of metals or pesticides. Bioaccumulation is important in microbial mining, removal of toxic metals from wastewater, and as a purification (bioremediation)process.
Bioassay A method for evaluating a substance by measuring its effect on living cells or organisms. Animals have been used extensively for the bioassay of pharmaceutical agents. However, bioassays using bacterial, plant or animal cells in culture are easier to handle than whole animals or plants, more cost effective, and avoid the ethical problems associated with testing of animals.
Bioaugmentation A technique used in bioremediation to increase the activity of bacteria that decompose pollutants.
Bioavailability The fraction of an administered compound that reaches the systemic circulation and is transported to the target tissue.
Biocatalysis The use of enzymes to catalyse chemical reactions. See biotransformation.
Biochemical simulation Use of dynamic systems modeling to simulate the chemical reactions involved in metabolism.
Biochemistry The chemistry of biological systems and processes.
Biochips Miniaturised arrays to large numbers of molecular substrates such as oligonucleotides in a defined pattern. Also known as DNA microarrays and microchips.
BioConductor An open source and open development software project to provide tools for the analysis and comprehension of genomic data (bioinformatics).
Biocontrol A process that uses living organisms to control the growth the development of pathogenic organisms. This is used as a method of pest control. Biotechnological approaches for biocontrol of pests and weeds include use of bacteria, viruses or fungi. The term is also used for the development of disease-resistant crops.
Bioconversion Conversion of one chemical into another by living organisms. This differs from biotransformation in which the conversion is brought about by enzymes. The major advantages of bioconversion are its extreme specificity and ability to work in moderate conditions. A major commercial application of bioconversion is in the manufacture of steroid drugs from plants.
Biocosmetics Cosmetics based on biological knowledge or with a biotechnological component. Biocosmetics can be categorised into three areas-biomaterials, biologically based ingredients, and medically rationalized products. The biomaterials used in Biocosmetics include collagen and collagen hydrolysate, and lipids such as liposomes as moisturizers. Biological ingredients in cosmetics include biotin, sphingosine, cyclodextrins and several pigments. Medically rationalised products include hypoallergenic products and UV-blocking agents.
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