Complex between mRNA, 30S ribosomal subunit and formyl-methionyl-tRNA that requires GTP and initiation factors to function.
The set of catalytic proteins required, in addition to mRNA and ribosomes, for protein synthesis to begin. In bacteria three distinct proteins have been identified: IF-1 (8 ...
inner cell mass
A group of cells found in the mammalian blastocyst that give rise to the embryo and are potentially capable of forming all tissues, embryonic and extra-embryonic, except the ...
The material that encases the two central microtubules of the ciliary axoneme.1. Hoechst 33258 dye
Cells added to start a culture or, in the case of viruses, viruses added to infect a culture of cells. Also for biological material injected into a human to induce immunity (a ...
The "fifth base" of nucleic acids. Important because it fails to form specific pair bonds with the other bases. In transfer RNAs, this property is used in the anticodon to ...
A cyclic hexahydric alcohol with 6 possible isomers. The biologically active form is myo-inositol.
Virtually all of the possible phosphorylated states of inositol have been reported to occur in living tissues. The hexaphosphate, phytic acid, is abundant in many plant tissues ...
(= IP3, InsP3)
Inositol 1,4,5 trisphosphate is important as a second messenger. It is released from phosphatidyl inositol bisphosphate by the action of a specific ...
Protein (30 kD) from chicken gizzard smooth muscle. Binds to the barbed ends of actin filaments and apparently allows insertion of further monomers.
(= IS elements)
Mobile nucleotide sequences that occur naturally in the genomes of bacterial populations. When inserted into bacterial DNA, they inactivate the gene concerned; ...
Generally, mutagenesis of DNA by the insertion of one or more bases. Specific examples: (1) oncogenesis by insertion of a retrovirus adjacent to a cellular proto-oncogene;
A variant of the patch clamp technique, in which a disc of plasma membrane covers the tip of the electrode, with the inner face of the plasma membrane facing outward, to the ...
Mechanical disruption of cell membranes gives rise to small closed vesicles surrounded by a bilayer membrane. These may be right-side out (ROV), or IOV if the topography is ...
Theory of antibody production, now considered untenable, in which antigen acted as template for the production of specific antibody as opposed to the clonal selectiontheory in ...
A polypeptide hormone (bovine insulin; 5780 D) found in both vertebrates and invertebrates. Secreted by the Bcells of the pancreas in response to high blood sugar levels, it ...
insulin-like growth factor
IGFs I and II are polypeptides with considerable sequence similarity to insulin. They are capable of eliciting the same biological responses, including mitogenesis in cell ...
Oncogene from mouse mammary carcinoma that encodes a secreted protein. Related to Drosophila gene wingless.
Oncogene from mouse mammary carcinoma that encodes a member of fibroblast growth factor receptorfamily.
integral membrane protein
A protein that is firmly anchored in a membrane (unlike a peripheral membrane protein). Most is known about the integral proteins of the plasma membrane, where important ...
Enzyme of the bacteriophage lambda ( l) that catalyses the integration of phage DNA into the host DNA.
Incorporation of the genetic material of a virus into the host genome.
In the Britten & Davidson model for the coordinate expression of unlinked genes in eukaryotes, sensor elements respond to changing conditions by switching on appropriate ...
Superfamily of cell surface proteins that are involved in binding to extracellular matrix components in some cases. Most are heterodimeric with a b subunit of 95 kD that is ...
Class of DNA element composed of a DNA integrase gene adjacent to a recombination site, at which one or more genes can be found inserted. Frequently, antibiotic resistance genes ...
An electron-dense junctional complex, at the end-to-end contacts of cardiac muscle cells, that contains gap junctions and desmosomes. Most of the disc is formed of a ...
Insertion into a pre-existing structure; eg. (a) nucleotide sequences into DNA (or RNA), (b) molecules into structures such as membranes.
Between cells: can be used either in the sense of connections between cells (as in intercellular junctions), or as an antonym for intra-cellular.
Cells found particularly in thymus-dependent regions of lymph nodes; they have dendritic morphology and accessory cell function.
interference diffraction patterns
The patterns arising from the recombination of beams of light or other waves after they have been split and one set of rays have undergone a phase retardation relative to the ...
Although all image formation depends on interference, the term is generally restricted to systems in which contrast comes from the recombination of a reference beam with light ...
interference reflection microscopy
An optical technique for detecting the topography of the side of a cell in contact with a planar substrate, and for providing information on the separation of the plasmalemma ...
Transcription factor. Deletion of the IRF-1 gene in mice leads to severe deficiency in NK cell function. Regulates gene for IL-15.
Lackie A family of glycoproteins produced in mammals that prevent virus multiplication in cells. IFN- a is made by leucocytes and IFN- b by fibroblasts after viral infection. ...
Compare intragenic suppression. The situation where a primary gene and the gene that suppresses it do not lie in the same chromosomal locus.
A variety of substances produced by leucocytes (not necessarily exclusively) and that function during inflammatory responses. (This is the definition recommended by the IUIS-WHO ...
Protein (17 kD: 152 amino acids) secreted by macrophages or accessory cells involved in the activation of both T- and B-lymphocytes in response to antigens or ...
interleukin-1 converting enzyme
Cytoplasmic cysteine protease that is uniquely responsible for cleaving proIL-1 b (31 or 33 kD) into mature IL-1 b (17.5 kD) ; the active cytokine is then released by a ...
Cytokine produced by Th2 helper T-cells, some B-cells and LPS-activated monocytes. Regulates cytokine production by a range of other cells.
Pleiotropic cytokine originally isolated from primate bone marrow stromal cell line. Stimulates T-cell-dependent B-cell maturation, megakaryopoiesis, various stages ...
(= IL-12; NK stimulatory factor; cytotoxic lymphocyte maturation factor)
Heterodimeric cytokine (35 kD and 40 kD) that enhances the lytic activity of NK cells, induces ...
Lackie Cytokine (12.4 kD) with anti-inflammatory activity. Produced by activated T-cells; inhibits IL6 production by monocytes and also the production of other ...
(= IL-14; high molecular weight B-cell growth factor; HMW-BCGF)
Cytokine (53 kD) produced by T-cells that enhances proliferation of activated B-cells and inhibits immunoglobulin ...
Cytokine that has effects very similar to IL-2 but in addition potently chemotactic for lymphocytes. Levels are elevated in the rheumatoid joint. Receptor shares b ...
(= IL-16, lymphocyte chemoattractant factor)
Secreted from CD8+ cells and will induce migratory responses in CD4 + cells (lymphocytes, monocytes and eosinophils). May bind to ...
Pro-inflammatory T-cell product (17 kD) that acts on receptors on a range of cells to activate NF k B. Induces expression of IL-6, IL-8 and ICAM-1 in fibroblasts and ...
(= interferon gamma inducing factor; IGIF)
First isolated from liver of mice during toxic shock; has sequence homology with IL-1 b and IL-1ra and has also been designated ...
(= IL-2; T-cell growth factor; thymocyte stimulating factor.)
Cytokine (17 kD) released by activated T-cells that causes activation, stimulates and sustains growth of other ...
Product of mitogen-activated T-cells: colony-stimulating factor for bone-marrow stem cells and mast cells.
(= IL-4, B-cell stimulating factor, BSF-1)
A B-cell growth and differentiation factor; also stimulates eosinophil precursor proliferation and differentiation.
Cytokine that is co-induced with interferon from fibroblasts, a B-cell differentiation factor, a hybridoma growth factor, an inducer of acute phase proteins, and a ...
(= IL-7; lymphopoietin 1)
Single-chain 25 kD cytokine (20 kD) originally described as a pre-B-cell growth factor but now known to have effects on a range of other cells, ...
(= IL-8; neutrophil activating protein, NAP-1)
One of the first chemokines to be isolated; one of the C-X-C family (8 kD). Secreted by a variety of cells and potently ...
Cytokine produced by T-cells, particularly when mitogen stimulated, that stimulates the proliferation of erythroid precursor cells (BFU-E). May act synergistically with ...
A class of cytoplasmic filaments of animal cells so named originally because their diameter (nominally 10nm) in muscle cells was intermediate between thick and thin ...
Region between the two membranes of mitochondria and chloroplasts. On the endosymbiont hypothesis, this space would represent the original phagosome.
Applied to the motile behaviour of crawling cells that, in the short term, show persistence and do not behave as true random walkers. Any intrinsic regulation of the random ...
General term for intracellular membrane systems such as endoplasmic reticulum. Not particularly helpful, but has the advantage of being non-committal.
Surface proteins (InlA, InlB) that mediate entry of Listeria monocytogenes into epithelial cells that express E-cadherin or L-CAM. There appears to be an internalin multigene ...
Neurons that connect only with other neurons, and not with either sensory cells or muscles. They are thus involved in the intermediate processing of signals.
Neuronal intermediate filament protein (68 kD). Subunit of Type IV filaments found in neurons of CNS.
The stage of the cell or nucleus when it is not in mitosis, hence comprising most of the cell cycle.
(1) Cells lying between but distinct from other cells in a tissue, a good example being the interstitial cells in Hydra that serve as stem cells.
(2) Cells lying between the ...
The endodermally-derived epithelium of the intestine varies considerably, but the absorptive epithelium of small intestine is usually implied. The apical surfaces of these ...
Inner layer of blood vessel, comprising an endothelial monolayer on the luminal face with a subcellular elastic extracellular matrix containing a few smooth muscle cells. ...
Inner layer of the wall of a pollen grain, resembling a primary cell wall in structure and composition. Also used for the inner wall layer of a spore.
The situation where a primary gene and the mutated gene that suppresses it lie within the same locus.
Particles (or complementary pits) seen in freeze fractured membranes. The cleavage plane is through the centre of the bilayer, and the particles are usually assumed to represent ...
A mucoprotein normally secreted by the epithelium of the stomach and that binds vitamin B12; the intrinsic factor/B12 complex is selectively absorbed by the distal ileum, though ...
(= intervening sequence)
A non-coding sequence of DNA within a gene (cf. exon), that is transcribed into hnRNA but is then removed by RNA splicing in the nucleus, leaving a ...
A polysaccharide of variable molecular weight (around 5 kD), that is a polymer of fructofuranose. Widely used as a marker of extracellular space, an indicator of blood volume ...
Proteins produced by bacterial cells that promote bacterial penetration into mammalian cells. The invasin produced by Yersinia pseudotuberculosis seems to bind to the ...
A term that should be used with caution; although most cell biologists would follow Abercrombie in meaning the movement of one cell type into a territory normally occupied by a ...
An index devised by Abercrombie & Heaysman as a means to estimate the invasiveness of cells in vitro. The index is derived from measurements on confronted explants of the cells ...
(= reverse antagonist)
Any ligand that binds to receptors and reduces the proportion in the active form. Has the opposite effects to an agonist and may actually reduce the ...
Individual in which one chromosome contains an inversion whereas the homologous chromosome does not.
(1) ("sucrase") Enzyme catalysing the hydrolysis of sucrose to glucose and fructose, so-called because the sugar solution changes from dextro-rotatory to laevo-rotatory during ...
Marker protein for keratinocyte differentiation first appearing in the upper spinous layer of the epidermis. Together with trichohyalin forms the scaffold for the cell ...
(1) Restoration of the normal size of an organ.
(2) Infolding of the edges of a sheet of cells, as in some developmental processes, notably gastrulation.
A transmembrane pore that presents a hydrophilic channel for ions to cross a lipid bilayer down their electrochemical gradients. Some degree of ion specificity is usually ...
Separation of molecules by absorption and desorption from charged polymers. An important technique for protein purification. For small molecules the support is usually ...
An electrode half-cell, with a semi-permeable membrane that is permeable only to a single ion. The electrical potential measured between this and a reference half-cell (eg. a ...
Radiation capable of ionizing, either directly or indirectly, the substances it passes through. a and b radiation are far more effective at producing ionization (and therefore ...
A molecule that allows ions to cross lipid bilayers. There are two classes: carriers and channels. Carriers, like valinomycin, form cage-like structures around specific ions, ...
Movement of ions as a result of an applied electric field. For example the delivery of a charged molecule from the end of a micropipette without hydraulic flow.
See inositol trisphosphate.
(= isopenicillin N synthase)
Non-haem iron-dependent oxidase (38 kD) that catalyses the formation of isopenicillin N from alpha-aminoadipylcysteinyl-valine (ACV).
(= isopropyl b-D-thiogalactoside)
Used to trigger gene expression that is under the control of gal promoter, particularly used in expression systems for producing protein.
Immune response genes, located within the MHC of vertebrates. Originally recognized as controlling the level of immune response to various synthetic polypeptides, they are now ...
(= IL-1 receptor associated kinase)
Associates with the IL-1R once IL-1 binds. Part of the kinase cascade that eventually leads to NF k B translocation to the nucleus and ...
A group of non-occluded viruses of insects; the crystalline array of virus particles in the cytoplasm of epidermal cells gives infected insects an irridescent appearance.
(= insulin receptor substrate-1)
Multi-site docking protein (180 kD) that is phosphorylated by insulin and IGF-1 receptors following ligand binding. The ...
(= ischemia (USA) )
Inadequate blood flow leading to hypoxia in the tissue.
(= immunostimulatory complexes)
Small cage-like structures that make it possible to present viral proteins to the immune system in an array, much as they would appear on the ...
islet amyloid peptide
Peptide of 37 amino acids that selectively inhibits insulin-stimulated glucose uptake in muscle. Structurally related to calcitonin gene related peptide.
Cells of the Islets of Langerhans within the pancreas. See A cells, B cells, D cells.
Islets of Langerhans
Groups of cells found within the pancreas: A cells and B cells secrete insulin and glucagon. See also D cells.
Antibody made in response to antigen from another individual of the same species.
Long stretches of GC- or AT-rich sequences of DNA associated with R and G chromosome bands respectively.
An intermediate in the tricarboxylic acid cycle(citric acid cycle).
Electrophoresis in a stabilized pH gradient. High-resolution method for separating molecules, especially proteins, that carry both positive and negative charges. Molecules ...
The pH at which a protein carries no net charge. Below the isoelectric point proteins carry a net positive charge; above it a net negative charge. Due to a preponderance of ...
Variants of enzymes that catalyse the same reaction, but owing to differences in amino acid sequence can be distinguished by techniques such as electrophoresis or isoelectric ...
A protein having the same function and similar (or identical sequence), but the product of a different gene and (usually) tissue-specific. Rather stronger in implication than ...
Natural antibodies that react against normal antigens of other members of the same species.
(= Ileu; I; 131 D)
Hydrophobic amino acid.
Alternative stereochemical forms of molecules containing the same atoms.
Tension generated in a muscle without contraction occurring: cross-bridges are being re-formed with the same site on the thin filament, and the tension (in striated muscle) is ...
Large family of molecules that include carotenoids, phytoids, prenols, steroids, terpenoids and tocopherols. May form only a portion of a molecule being attached to a ...