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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >>Laron Type Dwarfs Late Genes
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Lagging strand The strand of DNA that is synthesised discontinuously in the form of short Okazaki fragments in the 5  3 direction from a template running in the 3  5 direction.
Lambda A statistical parameter used in calculating BLAST scores. It is a natural scale for a scale for a scoring system and converts a raw score to a bit score.
Lambda chain One of two types of antibody light chains. See kappa chain.
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Lambda exonuclease An enzyme that catalyses the cleavage of single nucleotides with 5 –phosphate groups from the 5 –end of DNA.
Lambda(λ)-integrase family A site-specific recombination system that has relaxed topological requirements. It is seen in S. cerevisiae 2μplasmid and in the integration sites in the E. coli genome.
Lambda phage Temperate phage pf E.coli used as a cloning vector.
Lamella (pl: lamellae) A double-membrane structure, plate or vesicle formed by two membranes that lie parallel to each other.
Lamellipoda A cytoplasm-containing protrusion that extends out of the animal cell when it moves along the substrate.
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Lamin See nuclear lamin
Laminar airflow cabinet; laminar airflow hood A cabinet for the inoculation of cultures. The working area is kept sterile by a continuous, non-turbulent flow of sterilized air through a HEPA filter. See HEPA filter; prefilter.
Laminarin A storage polysaccharide of the brown algae.
Laminins A family of long adhesive proteins. They contain multiple domains that bind different types of collagen, matrix proteins, polysaccharides, cell surface adhesion receptors and extracellular signaling molecules such as hormones and growth factors. These proteins are involved in the organisation of ECM components, regulation of cell-matrix adhesion, cell migration and maintenance of cell shape.
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Lambrush chromosomes Giant diplotene chromosomes present in the amphibian oocyte nuclei. The loops present in these chromosome are active sites of transcription.
LAN (Local Area Network) A network that connects computers in a small, defined area such as those in a single wing or group of buildings.
Langmuir-Blodgett films Thin films of molecules formed on the surface of water, often used to describe lipid films in which both sides are in water. These films form because the hydrophobic tails of lipids associate with each other, while the hydrophilic heads protrude into the water. See liposome.
LARD Lymphocyte-associated receptor of death. LARD is a receptor for Apo-3L and is also known as DR3, WSL-1, TRAMP and APO-3.
Lariat An intermediate formed during posttranscriptional processing of mRNA that has a circular structure with a tail. The lariat is created by the formation of an unusual 5 2 phospho-diester bond during removal of introns and splicing of exons. The introns released in lariat form is linearised and eventually degraded.
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Laron type dwarfs Dwarfs who have high plasma GH with reduced levels of IGF-I and IGF-II and lack functional GH receptors.
Laser Acronym for Light Amplification by Stimulated Emission of Radiation. It is generated when a group of atoms emits photons in synchrony. Lasers are used in biological analysis including flow cytometry.
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Laser capture microscopy A technique that allows obtaining DNA, RNA and proteins of small and pure populations of cells. It is primarily used for separation of tumour cells although many additional applications of this technology such as for developmental biology or in vitro fertilisation, have evolved. The combination of laser capture microscopy with other highly sensitive, high-throughput technologies such as microscopy offers exciting new possibilities for scientists in research and clinic.
Lassa fever virus An RNA-containing virus msember of the Arena virus family discovered in Nigeria. It is known to cause acute infection characterised by fever, malaise, throat lesions sand pneumonia.
Late genes Genes that are expressed late during the life cycle of a virus. These genes encode proteins required for packaging viral DNA replicated early in the viral life cycle.
Late period A period in phage development that follows the initiation of DNA replication.
Late phase response Part of type I hypersensitivity that requires protein synthesis and occurs several hours after histamine release.
Latent agent. A virus (generally) present in a host organism without producing any symptoms.
Latent phase See lag phase.
Late-replicating material That part of the chromosome (usually heterochromatin) that replicates only at the end of S phase.
LAV Acronym for Lympho Adenopathy Virus. It is another name for HIV that causes AIDS.
Law of mass action The law that states that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants.
Lawn A uniform and uninterrupted layer of bacterial growth, in which individual bacterial colonies cannot be visualised.
LCAT (Iecithin cholesterol acyltransferase) An enzyme that requires apoA-I as activator. LCAT converts phospholipids and free cholesterol into cholesterol ester and lysolecithin.
LCR See ligase chain reaction.
LD50 (lethal dose50%) The amount of a chemical required to kill 50% of the test population. The higher the LD50, the lower is the toxicity of the chemical.
LDL receptor A transmembrane protein in liver cells that binds to low density lipoproteins (LDL) followed by endocytosis of LDL into the cells and degradation. This is one of the major pathways for LDL cholesterol.
Leaching Use of microorganisms to isolate metals from mineral ores by solubilization and washing out (leaching) of the metal from the ore. It is major component of biohydrometallurgy.
Lead compound A substance that possesses the characteristics of an ideal drug and interacts with a specific target. It can be improved by modification to make drug targets with reduced side effects (lead optimization).
Lead optimization The process of converting a putative lead compound (hit) into a therapeutic drug with maximal activity and minimal side affects. This involves use of a combination of computer-based drug design, medicinal chemistry and pharmacology.
Leader peptidase An integral membrane protein that catalyses cleavage of the leader sequence during insertion of preproteins into target membranes.
Leader peptide See signal sequence.
Leader sequence 1. A sequence of nucleotides at the 5’ end of an mRNA that is not translated into protein. 2. Short N-terminal sequence in a protein responsible for passage into or through a membrane.
Leading strand The strand of DNA that is synthesised continuously in the 5 3 direction during replication.
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