Nucleotide sequences in DNA that are present in the genome as numerous copies. Originally identified by the value on the Cot curve derived from kinetic studies of DNA ...
Methods in the preparation of specimens for transmission electron microscopy. The specimen (for example, a piece of freeze fractured tissue) is shadowed with metal and coated ...
Technique for testing the genetic characteristics of bacterial colonies. A dilute suspension of bacteria is first spread, in a petri dish, on agar containing a medium expected ...
Generic (and rather unhelpful) term for an enzyme that duplicates a polynucleotide sequence (either RNA or DNA). The term is more usefully restricted to the enzyme involved in ...
Copying, but usually the production of daughter strands of nucleic acid from the parental template.
replication factor A
(= replication protein A; RPA)
Protein that associates, together with the PIK3-kinase-like kinase (ATM), at sites where homologous regions of DNA interact during meiotic ...
Point at which DNA strands are separated in preparation for replication. Replication forks thus move along the DNA as replication proceeds.
Intermediate stage(s) in the replication of a RNA virus; a copy of the original RNA strand, or of a single-strand copy of the first replicative intermediate. Essentially an ...
Tandem regions of replication in a chromosome, each about 30 m m long, derived from an origin of replication. By definition a replicon must contain an origin of replication.
Complex of proteins involved in the replication (elongation) of DNA that moves along as the new complementary strand is synthesized. On this basis a minimum content would be DNA ...
A gene that encodes an easily assayed product (eg. CAT) that is coupled to the upstream sequence of another gene and transfected into cells. The reporter gene can then be used to ...
A protein that binds to an operator of a gene preventing the transcription of the gene. The binding affinity of repressors for the operator may be affected by other ...
Propagation of organisms. The act of producing new organisms. May be asexual or sexual.
Sea urchin peptide hormone, affecting motility and metabolism. Receptor is a plasma-membrane guanylate cyclase.
Membrane shells formed by lysis of erythrocytes resealed by adjusting the cation composition of the medium. Relatively impermeable, although more permeable than the original ...
Alkaloid derived from Rauwolfia ; blocks the packaging of noradrenaline in to presynaptic vesicles. Useful experimental tool to determine the involvement of sympathetic ...
(1) Secondary lysosomes containing material that cannot be digested.
(2) The surplus cytoplasm shed by spermatids during their differentiation to spermatozoa. Usually the ...
Amorphous rubber-like protein found in insect cuticle: similar to elastin, though there is no fibre formation.
Potent analogue of capsaicin from Euphorbia resinifera (flowering cactus). An agonist at vanilloid receptor-1.
Complete return to normal structure and function: used, for example, of an inflammatory lesion, or of a disease. See also resolving power.
See recombinase, site-specific recombination.
(1) The resolution of an optical system defines the closest proximity of two objects that can be seen as two distinct regions of the image. This limit depends upon the ...
Pink fluorescent dye; a caged form of resorufin (non-fluorescent unless activated - released - by irradiation with UV) coupled to G-actin and microinjected has been used as a ...
Term used by physiologists to describe the process of breathing and by biochemists to describe the intracellular oxidation of substrates coupled with production of ATP and ...
respiratory enzyme complex
The enzymes that make up the respiratory chain: NADH-Q reductase, succinate-Q reductase, cytochrome reductase, cytochrome C and cytochrome oxidase.
Re-occlusion of coronary arteries after angioplasty (PTCA) or after replacement with blood vessels from elsewhere. Probably due to excessive proliferation of vascular smooth ...
The electrical potential of the inside of a cell, relative to its surroundings. Almost all animal cells are negative inside; resting potentials are in the range -20 to -100mV, ...
(= restriction enzymes)
Class of bacterial enzymes that cut DNA at specific sites. In bacteria their function is to destroy foreign DNA, such as that of bacteriophages (host DNA ...
restriction fragment length polymorphism
Technique, also known as DNA fingerprinting, that allows familial relationships to be established by comparing the characteristic polymorphic patterns that are ...
The fragments of DNA generated by digesting DNA with a specific restriction endonuclease. Each of the fragments ends in a site recognized by that specific enzyme.
Map of DNA showing the position of sites recognized and cut by various restriction endonucleases.
(of cell cycle) A point, late in G1, after which the cell must, normally, proceed through to division at its standard rate.
Toxin (149 residues) produced by Aspergillus restrictus. One of the aspergillins; see alpha-sarcin.
A human oncogene, encoding a receptor tyrosine kinase.
The sequence of amino acids on proteins that indicates that they are to be retained in the secretory processing system, for example the Golgi apparatus, and not passed on and ...
Calcium/calmodulin-dependent protein kinase IV-like protein (35 kD) found in rat retina, mainly in outer segment of photoreceptors and dendrites of inner plexiform layers. See ...
Fine fibres (of reticulin) found in extracellular matrix, particularly in lymph nodes, spleen, liver, kidneys and muscles.
The lower region of extracellular matrix underlying an epithelial monolayer, separated from the basal surface of the epithelial cells by the basal lamina. The reticular ...
Constituent protein of reticular fibres: collagen Type III.
Immature red blood cells found in the bone marrow, and in very small numbers in the circulation.
Cell lysate produced from reticulocytes; used as an in vitro translation sytem.
The phagocytic system of the body, including the fixed macrophages of tissues, liver and spleen. Rather old-fashioned term that is coming back into use; ‘mononuclear phagocyte ...
Cells of the reticuloendothelial system, found particularly in lymph nodes, bone marrow, and spleen. In lymph nodes they are stromal cells and probably not reticuloendothelial ...
Light-sensitive layer of the eye. In vertebrates, looking from outside, there are four major cell layers: (i) the outer neural retina, which contains neurons (ganglion cells, ...
Aldehyde of retinoic acid (vitamin A) ; complexed with opsin forms rhodopsin. Photosensitive component of all known visual systems. Absorption of light causes retinal to shift ...
The other light-sensitive cell type of the retina, that, unlike retinal rods, is differentially sensitive to particular wavelengths of light, and is important for colour ...
Major photoreceptor cell of vertebrate retina (about 125 million in a human eye). Columnar cells (about 40 m m long, 1 m m diameter) having three distinct regions: a region ...
Disease caused by overactivity of the pigmented retinal epithelial cells, leading to damage and occlusion of photoreceptors and blindness.
A problem that has exercised developmental biologists is the way in which nerve fibres from the developing retina are ‘mapped’ on to the tectum of the brain. There seems to ...
Malignant tumour of the retina, usually arising in the inner nuclear layer of the neural retina. Retinoblastoma is unusual in being caused by an autosomal dominant mutation ...
(= vitamin A)
The aldehyde (retinal) has long been known to be involved in photoreception, but retinoic acid has other roles. There are cytoplasmic retinoic acid binding proteins ...
Thin projections from crawling cells associated with areas where the cell body is becoming detached from the substratum, but focal adhesions persist. Usually contain a bundle ...
retrograde axonal transport
The transport of vesicles from the synaptic region of an axon towards the cell body: involves the interaction of MAP1C with microtubules.
Transposable element with a transpositional mechanism requiring reverse transcriptase in a manner reminiscent of retroviruses, to which they may be related.
See Retroviridae. Retroviral vectors are used in the genetic modification of cells as a means of introducing foreign DNA into the genome. For example, RVs encoding ...
Viruses with a single-stranded RNA genome (Class VI). On infecting a cell the virus generates a DNA replica by action of its virally coded reverse transcriptase. Oncovirinae ...
The technique of determining a gene\'s function by first sequencing it, then mutating it, and then trying to identify the nature of the change in the phenotype.
reverse passive haemagglutination
If antibodies are bonded to the surface of red blood cells haemagglutination will occur if the appropriate bi- or multivalent antigen is added in soluble or microparticulate ...
RNA-directed DNA polymerase. Enzyme first discovered in retroviruses, that can construct double-stranded DNA molecules from the single-stranded RNA templates of their genomes. ...
Reversion of a mutation occurs when a second mutation restores the function that was lost as a result of the first mutation. The second mutation causes a change in the DNA ...
A constant without dimensions that relates the inertial and viscous drag acting to hinder a body moving through fluid medium. For cells the Reynold\'s number is very small; ...
(= release factor; RF-1, RF-2, RF-3, eRF-1)
Proteins that are involved in the release of the nascent polypeptide from the ribosome. In bacteria RF-1 (40 kD) is specific for ...
See restriction fragment length polymorphism.
A domain found in fibronectin and related proteins, recognized by integrins. In most cases, the consensus is -R-G-D-S- (arginine-glycine-aspartic acid-serine).
(= Rh factor)
Rhesus factor: see rhesus blood group.
Order of aquatic turbellaria (flatworms). Superceded as a classification.
Class V viruses with a single negative strand RNA genome and an associated virus-specific RNA polymerase. The capsid is bullet shaped and enveloped by a membrane that is formed ...
Plant cell-wall polysaccharide consisting principally of rhamnose and galacturonic acid. Present as a major part of the pectin of the primary cell wall. Two types known: ...
(= 6-deoxy L-mannose)
A sugar found in plant glycosides.
A taxis in response to the direction of flow of a fluid.
Rhesus blood group
Human blood group system with allelic red cell antigens C, D and E. The D antigen is the strongest. Red cells from a Rhesus-positive foetus cross the placenta and can sensitise a ...
Disease involving inflammation of joints and damage to heart valves that follows streptococcal infection and is believed to be autoimmune, ie. antibodies to streptococcal ...
Chronic inflammatory disease in which there is destruction of joints. Considered by some to be an autoimmune disorder in which immune complexes are formed in joints and excite ...
Complex of IgG and anti-IgG formed in joints in rheumatoid arthritis. Serum rheumatoid factors are more usually formed from IgM antibodies directed against IgG.
Picornaviridae that largely infect the upper respiratory tract. Include the common cold virus and foot-and-mouth disease virus.
Gram negative bacterium that fixes nitrogen in association with roots of some higher plants, notably legumes. Forms root nodules, in which it is converted to the nitrogen-fixing ...
Portion of a cell or organism that serves as a basal anchor to the substratum.
Striated contractile structure attached to the basal region of the cilium in a variety of ciliates and flagellates. May regulate the flagellar beat pattern, and is sensitive to ...
Phylum that includes single celled amoebae such as Amoeba proteus.
(= r factors)
Protein factors found in prokaryotes, especially E. coli, involved in the termination of transcription. Mutations in rho may cause the RNA polymerase to read ...
Genes coding for small GTP-binding proteins; implicated in actin organization and the interaction of the cytoskeleton with intracellular membranes. See also ras and rab.
A group of triphenylmethane-derived dyes are referred to as rhodamines, lissamines etc. Many are fluorescent and are used as fluorochromes in labelling proteins and membrane ...
Reduviid blood-sucking bug, vector of Trypanosoma cruzi in South America. Much used by insect physiologists because the the transition from one instar to the next is triggered ...
(= red algae)
Division of algae, many of which have branching filamentous forms and red coloration. The latter is due to the presence of phycoerythrin. The food reserve is ...
(= visual purple)
Light-sensitive pigment formed from retinal linked through a Schiff\'s base to opsin: rhodopsin is an integral membrane protein found in the discs of ...
A purple nonsulphur bacterium with a spiral shape; contains the pigment bacteriochlorophyll and under anaerobic conditions photosynthesises using organic compounds as electron ...
Neuromeres or segments in the hindbrain region that are of developmental significance. Shown to be lineage restriction units in that cells of adjacent rhombomeres do not mix ...
Protein (71 kD, 643 residues) that interacts with rho-GTP. Has sequence homology with the N terminal region of protein kinase N though possesses no catalytic activity.
Electron-opaque dense body found in the apical complex of parasitic protozoa of the Phylum Apicomplexa.
Ribavirin is an orally active guanoside analogue that inhibits the replication of a variety of RNA viruses. It inhibits inosine monophosphate dehydrogenase.
Ultrastructurally distinct type of synapse found in a variety of sensory receptor cells such as retinal photoreceptor cells, cochlear hair cells and vestibular organ ...
(= vitamin B2)
Ribose attached to a flavin moiety that becomes part of FAD and FMN.
(= RNAse, RNAase)
Widely distributed type of enzyme that cleaves RNA. May act as endonucleases or exonucleases depending upon the type of enzyme. Generally recognize target by ...
Complexes of RNA and protein involved in a wide range of cellular processes. Besides ribosomes (with which RNP was originally almost synonymous), in eukaryotic cells both initial ...
Glycoproteins of the endoplasmic reticulum that interact with ribosomes whilst co-translational insertion of membrane or secreted proteins is taking place. Ribophorins may form ...
Somewhat casual term for an RNA segment used to probe for a complementary nucleotide sequence -either in the mRNA pool or in the DNA of a cell.
A monosaccharide pentose of widespread occurrence in biological molecules, eg. RNA.
Periplasmic binding proteins of bacteria that interact either with the ribose transport system or with the methyl-accepting chemotaxis protein, MCP III ( trg ).
Proteins present within the ribosomal subunits. In prokaryotes there are 31 proteins in the large subunit and 21 in the small subunit. Eukaryotic subunits have 50 (large ...
A heterodimeric multi-subunit enzyme composed of ribonucleoprotein and protein subunits. Interacts with aminoacylated tRNAs, and mRNAs and translates protein coding sequences ...
The RNA complement of a cell - by analogy with phenotype or genotype.
RNA with catalytic capacity - an enzyme made of nucleic acid not protein. Of particular interest because of the implications for self-replicating systems in the earliest stages ...
ribulose bisphosphate carboxylase
Enzyme responsible for CO2 fixation in photosynthesis. Carbon dioxide is combined with ribulose diphosphate to give two molecules of 3-phosphoglycerate, as part of ...
Highly toxic lectin (66 kD) from seeds of the castor bean, Ricinus communis. Has toxic A subunit (32 kD), carbohydrate-binding B subunit (34 kD). Toxic subunit inactivates ...