Polymers of (arbitrarily) more than about ten monosaccharide residues linked glycosidically in branched or unbranched chains.
Potential regulator of cell-cell interactions. Polysialic acid chains in glycoproteins may have negative regulatory effects on cell-cell contact. Thus the low PSA form of NCAM ...
Situation in which all chromosomes are present, and some are present in greater than the diploid number, for example, trisomy 21.
Penetration of more than one spermatozoon into an ovum at time of fertilization. Occurs as normal event in very yolky eggs (eg. bird), but then only one sperm fuses with egg ...
Giant chromosomes produced by the successive replication of homologous pairs of chromosomes, joined together (synapsed) without chromosome separation or nuclear division. They ...
Homopolymer of uridylic acid. Historically, was used as an artificial mRNA in cell-free translationsystems, where it coded for polyphenylalanine; thus began the deciphering of ...
Polymer used to bind phenols in plant homogenates, and hence to protect other molecules, especially enzymes, from inactivation by phenols. Also occasionally used to produce ...
Severe glycogen storage disease caused by deficiency in a (1-4) -glucosidase, the lysosomal enzyme responsible for glycogen hydrolysis. Even though the non-lysosomal ...
(= Ponceau S; Fast Ponceau 2B)
Dye used to stain proteins.
Developmentally-regulated 17 kD transmembrane glycoprotein from Dictyostelium that regulates actin binding and nucleation. Preferentially located at actin-rich regions such ...
population diffusion coefficient
Coefficient that describes the tendency of a population of motile cells to diffuse through the environment. Its use presupposes that the cells move in a random-walk.
Transmembrane matrix proteins (37 kD) found in the outer membranes of Gram positive bacteria. Associate as trimers to form channels (1nm diameter, ca 105 per bacterium) through ...
Any of a group of disorders in which there is excessive excretion of porphyrins or their precursors.
Pigments derived from porphin: all are chelates with metals (Fe, Mg, Co, Zn, Cu, Ni). Constituents of haemoglobin, chlorophyll, cytochromes.
Effect on the expression of a gene depending upon its position relative to other genes on the chromosome. Moving (transposing) a gene from an inactive region to an active region ...
Identification of a gene based on its location in the genome. Typically, this will result from linkage analysis based on a mutation in the target gene, followed by a ...
The instructions that are interpreted by cells to determine their differentiation in respect of their position relative to other parts of the organism, eg. digit formation in ...
Mechanism for gene regulation that requires that a regulatory protein must interact with some region of the gene before transcription can be activated.
positive strand RNA viruses
Class IV and VI viruses that have a single-stranded RNA genome that can act as mRNA (plus strand) and in which the virus RNA is itself infectious. Includes Picornaviridae, ...
Changes that occur to proteins after peptide bond formation has occurred. Examples include glycosylation, acylation, limited proteolysis, phosphorylation, isoprenylation. ...
That portion of the blood circulation immediately downstream of the capillary network; the region having the lowest wall-shear stress, and the most common site of leucocytic ...
In a chemical synapse, the cell that receives a signal (binds neurotransmitter) from the presynaptic cell and responds with depolarization. In an electrical synapse, the ...
In a synapse, a change in the resting potential of a postsynaptic cell following stimulation of the presynaptic cell. For example, in a cholinergic synapse, the release of ...
(= 43 kD postsynaptic protein)
A peripheral membrane protein thought to help anchor acetylcholine receptors in the postsynaptic membrane. Highly conserved.
Ion channel selective for potassium ions. There are diverse types with different functions, for example: delayed rectifier channels, M-channels, A-channels, inward rectifier ...
Lectin from the potato, Solanum tuberosum. Binds to N-acetyl glucosaminyl residues.
Increase in quantal release at a synapse following repetitive stimulation. Whereas facilitation at synapses lasts a few hundred milliseconds, potentiation may last minutes to ...
Transport of small molecules across membrane using caveolae rather than coated vesicles.
A conserved protein domain of around 150 amino acids, composed of a 20 amino acid homeobox domain and a larger POU-specific domain, and so is the target of some transcription ...
Class I viruses with double-stranded DNA genome that codes for more than 30 polypeptides. They are the largest viruses and their shell is complex, consisting of many layers, and ...
The phosphoprotein (60 kD) encoded by the srconcogene. A tyrosine kinase.
(= peroxisome proliferator-activated receptors)
PPAR a stimulates b -oxidative degradation of fatty acids, PPAR g promotes lipid storage by regulating adipocyte ...
(= purified protein derivative)
Protein purified from the culture supernatant of tubercle bacteria ( Mycobacterium tuberculosis S and used as a test antigen in Heaf and Mantoux ...
(= peptidyl-prolyl cis-trans isomerase)
Enzymes that accelerate protein folding by catalysing cis-trans isomerisations. Immunophilins are PPIases though their enzymic activity ...
Pleuropneumonia-like organisms. See mycoplasma.
The form of phytochrome that absorbs light in the red region (660 m), and is thus converted to Pfr. In the dark the equilibrium between Pr and Pfr favours Pr, which is ...
Syndrome in which there is an absence of paternal chromosome 15q11q13. Short stature, obesity and mild mental retardation are features of the syndrome. Uniparental disomy leads ...
Antagonist of a -adrenergic receptors.
A pre-protein is a form that contains a signal sequence that specifies its insertion into or through membranes. A pro-protein is one that is inactive; the full function is only ...
Band of microtubules 1-3 m m wide that appears just below the plasma membrane of a plant cell before the start of mitosis. The position of the pre-prophase band determines the ...
Any antibody that forms a precipitating complex (a precipitin line) with an appropriate multivalent antigen. The term is now outmoded.
(= 1,4-pregnadiene-11b,17a, 21-triol-3,20-dione)
Steroid with glucocorticoid action, very similar to prednisone. An effective anti-inflammatory drug but with serious side ...
(= 1,4-pregnadiene-17a, 21-diol-3,11,20-trione)
Synthetic steroid that acts as a glucocorticoid, with powerful anti-inflammatory and anti-allergic activity.
Rarely-used term that designates an extra stage in the prophase of meiosis I. Usually lumped in with leptotene.
Post-translational addition of prenyl groups to a protein. Farnesyl, geranyl or geranyl-geranyl groups may be added. Consequence is usually to promote membrane association.
Rarely used term to designate an extra stage of mitosis, normally included as part of prophase.
Vesicles near the maturation face of the Golgi. Also known as Golgi condensing vacuoles.
Multi-pass transmembrane proteins, PS1 and PS2, found in Golgi. Mutations in genes for PS1 are associated with 25% of early onset Alzheimer\'s disease and altered amyloid b ...
Cells in the rear portion of the migrating slug (grex) of a cellular slime mould, which will later differentiate into spore cells. Can be recognized as having different ...
Cells at the front of the migrating grex of cellular slime moulds that will form the stalk upon which the sorocarp containing the spores is borne. See prespore cells.
In a chemical synapse, the cell that releases neurotransmitter that will stimulate the postsynaptic cell In an electrically-synapsed system, the cell that has the first ...
Rarely used term to designate an extra stage in the prophase of meiosis I. Usually lumped in with zygotene.
Large flattened polygonal cells of the stratum germinosum of the epidermis (just above the basal stem cells), that appear in the light microscope to have fine spines projecting ...
An 8-aminoquinoline drug used to treat malaria. Affects the mitochondria of the exo-erythrocytic stages (see Plasmodium), but the mechanism is not understood. The most ...
primary cell culture
Of animal cells, the cells taken from a tissue source and their progeny grown in culture before subdivision and transfer to a subculture.
primary cell wall
A plant cell wall that is still able to expand, permitting cell growth. Growth is normally prevented when a secondary wall has formed. Primary cell walls contain more pectin ...
primary immune response
The immune response to the first challenge by a particular antigen. Usually less extensive than the secondary immune response, being slower and shorter-lived with smaller ...
The enlarging ovum before maturity is reached, as opposed to the secondary oocyte or polar body.
A stage in the differentiation of the male germ cells. Spermatogonia differentiate into primary spermatocytes, showing a considerable increase in size in doing so; primary ...
RNA transcript immediately after transcription in the nucleus, before RNA splicing or polyadenylation to form the mature mRNA.
The mass of tumour cells at the original site of the neoplastic event - from the primary tumour metastasis will lead to the establishment of secondary tumours.
The enzyme that polymerizes nucleotide triphosphates to form oligoribonucleotides in a 5\' to 3\' direction. The enzyme synthesizes the RNA for RNA-DNA sequences that later ...
Technique for finding the transcriptional start site of a gene. mRNAs cannot be relied on to be complete at the 5&’ end, so a labelled antisense oligonucleotide primer is ...
Treatment that does not in itself elicit a response from a system but that induces a greater capacity to respond to a second stimulus.
Large cell with euchromatic nucleus found in mammalian embryos. In the mouse, the cells are located in the yolk sac and are responsible for early production of erythrocytes with ...
Thickened streak of cells in early mammalian and avian embryos - marks location of embryonic axis. Hensen&’s node is at the end of the primitive streak until the cellular ...
primordial germ cells
Germ cells at the earliest stage of development. Since germ cells may originate in the embryo at some distance from the gonads they then have to migrate to the gonadal ...
Complex of proteins involved in the synthesis of the RNA primer sequences used in DNA replication. Main components are primase and DNA helicase that move as a unit with the ...
See PrP, Gerstmann-Straussler-Scheinker syndrome. Suggested as the causative agents of several infectious diseases such as scrapie (in sheep), kuru and Creutzfeldt-Jakob ...
Extracted from shark liver. Will induce a lupus-like syndrome in non-autoimmune mice and a form of experimental arthritis.
(= PKC related kinase; PKN)
Serine/threonine kinases (120 kD). PRK-1 is found in hippocampus and is activated by phospholipids and arachidonic acid, binds to rho-GTP and ...
See protein kinase N.
Enzyme that does not have full (or any) function until an inhibitory sequence has been removed by limited proteolysis. See also zymogen.
Organic base (234 D). Procaine butyrate, borate and hydrochloride are used as local anaesthetics.
Plant meristem that gives rise to the primary vascular system.
The forming centriole composed of microtubules. Multiple procentrioles are present in some cells as a structure called the blepharoplast.
Triple-helical trimer of collagen molecules in which the terminal extension peptides are linked by disulphide bridges; the terminal peptides are later removed by specific ...
The proteases that remove the terminal extension peptides of procollagen; deficiency of these enzymes leads to dermatosparaxis or Ehlers-Danlos syndrome.
A prodromal sign is an early indication of a disease - often before classical symptoms appear.
Actin-binding protein (15 kD) that forms a complex with G-actin rendering it incompetent to nucleate F-actin formation. The profilin-actin complex seems to interact with ...
In development a "parent" cell that gives rise to a distinct cell lineage by a series of cell divisions.
Accelerated ageing syndrome in which most of the characteristic stages of human senescence are compressed into less than a decade. Defect probably in DNA repair.
Hormone (314 D) produced in the corpus luteum, as an antagonist of oestrogens. Promotes proliferation of uterine mucosa and the implantation of the ...
programmed cell death
A form of cell death, best documented in development, in which activation of the death mechanism requires protein synthesis. Morphologically, the cell appears to die by ...
An undifferentiated population of mesenchyme cells beneath the apical ectodermal ridge of the chick limb bud from which the sucessive parts of the limb are laid down in a ...
A protein hormone before processing to remove parts of its sequence and thus make it active.
Organisms, namely bacteria and cyanobacteria (formerly known as blue-green algae), characterized by the possession of a simple naked DNA chromosome, occasionally two such ...
Pituitary lactogenic hormone (23 kD), synthesized on ER-bound ribosomes as preprolactin that has an N-terminal signal peptide that is cleaved from the mature form. The ...
The disorganized membrane aggregations in chloroplasts that have been deprived of light (etioplasts).
proliferating cell nuclear antigen
Commonly used marker for proliferating cells, a 35 kD protein that associates as a trimer and as a trimer interacts with DNA polymerases d and e; acts as an auxiliary ...
(of epidermis) The basal layer of the mammalian epidermis contains cells that undergo repeated divisions. The cells outwards from a particular basal cell are often derived from ...
A hormone, related to prolactin, associated with the induction of cell division that is triggered by serum.
(= pro; P; 115D)
One of the 20 amino acids directly coded for in proteins. Structure differs from all the others, in that its side chain is bonded to the nitrogen of the a ...
Rarely-used term that designates an extra stage in mitosis, starting with the breakdown of the nuclear envelope. Usually lumped in with metaphase.
A region of DNA to which RNA polymerase binds before initiating the transcription of DNA into RNA. The nucleotide at which transcription starts is designated +1 and ...
Activation of a gene by the nearby integration of a virus. The long-terminal repeat acts as a promoter for the host gene. A form of insertional mutagenesis.
Cells of the bone marrow that derive from myeloblasts and will give rise to myelocytes; precursors of myeloid cells and neutrophil granulocytes.