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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >>National Human Genome Research Institute (NHGRI) - Near Patient Testing
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Nanogram
0.000000001 or 10-9 grams.
Nanomaterial
A material with an average grain size less than 100 nanometres.
Nanometre
1 × 10-9 m. One millionth of a millimetre, also termed millimicron; equal to 10 Angstroms.
Nanoparticle
A microscopic particel whose size is measured in nanometres.
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Nanoscale
Refers to objects with sizes in the range of 1-100 nanometers in at least one dimension.
Nanoscience
The study of phenomena at the nanoscale (eg. atoms, molecules, and macromolecules) where properties differ significantly from those at a larger scale.
Nanotechnology
The design, characterisation, production and application of structures, devices and systems that exploit the special properties at the nanoscale by manipulating shape and size. The concept was described by Richard Feynman and popularised by Eric Drexler. Nanotechnology includes the development of quantum dots as labelling agents. Two main subfields of nanotechnology are nanovectors for the administration of targeted therapeutic and imaging moieties, and the precise patterning of surfaces. A large number of nanovectors are currently under study. By combining nanovectors with preferred therapeutic and biological targeting moieties, it might be possible to obtain a very large number of novel, personalised therapeutic agents.
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Narcosis
Reversible depression of the central nervous system characterised by stupor and insensibility.
Narrow-host
range plasmid A plasmid capable of replicating in one or a few different bacterial species.
Narrow-sense heritability
In quantitative genetics, the proportion of the phenotypic variance that arises form variation in breeding values.
Nascent HDL
A discoid particle containing phospholipids, free cholesterol and apoproteins. Nascent HDL is converted to plasma HDL by uptake of lipids and apoproteins from chylomicrons and VLDL undergoing catabolism in the plasma.
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Nascent protein
A polypeptide that is being synthesised on ribosomes.
Nascent RNA
The initial RNA transcript before processing has occurred.
National Centre for Biotechnology
Information (NCBI) A national resource for molecular biology information that generates public databases and conducts research in computational biology. It is a division of the NIH.
National Human Genome Research Institute (NHGRI)
An institute of NIH set up to head the Human Genome Project. It supports large-scale sequencing and analysis of the human genome as well as comparative genome projects, genome informatics and ethical, legal and social issues (ELSI) that arise as a result of human genome research
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Native conformation
The biologically active conformation of a macromolecule.
Native gels
Polyacrylamide gels without SDS used to study proteins in their native state. Since SDS is not used, the proteins are not denatured prior to loading. The proteins are separated according to their different electrophoretic mobilities and the sieving effects of the gel.
Native protein
The naturally occurring state of a protein.
Natriuresis
Excretion of excessive amounts of sodium in the urine.
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Natural killer (NK) cells
Naturally occuring, large, granular, lymphocyte-like cytotoxic cells of the innate immune system. These are capable of killing cells infected by virus and tumour cells. These may play a role in resistance to tumours. They do not exhibit antigenic specificity, and their number does not increase by immunisation.
Natural passive immunity
Immunity conferred by the mother on the foetus or newborn.
Natural products
A chemical or material derived from a living organism as opposed to chemical synthesis. These include drugs or therapeutics from microorganisms, plants and animals. Microorganisms produce a wide range of chemicals including antibiotics such as penicillin. Chemicals derived from plants include menthol from mint, limonene from lemons, caffeine from tea, and anticancer drugs such as vincristine. Potential therapeutic products made from animals include the antithrombin protein hirudin and the anticancer drug antistatin from leeches.
Natural selection
The differential survival and reproduction of organisms due to differences in characteristics that influence their ability to use environmental resources.
NBRF/PIR
National Biomedical Research Foundation/Protein Information Resource.
A flat file format for representing sequence information.
NCBI
See National Centre for Biotechnology Information.
NCEs
(New Chemical Entity) Compounds identified as potential drugs that are sent from research and development into clinical trials to analyse their suitability.
NCGR
The National Centre for Genome Resources.
NDP
Ribonucleoside diphosphate. See nucleotide; ribonucleoside triphosphate (NTP).
Near infrared (NIR)
Radiation in the 800-2000 nm wavelength range. NIR spectra are useful in characterising the chemicals in a mixture are finds application in sensors in diabetes monitoring and as a fermentation process control aid.
Near-patient Testing
Tests that can be performed outside the clinical laboratory at the bedside, by the patients themselves, non-laboratory staff, nurses or general practitioners. These include simple as well as sophisticated tests.
Nebulin
A large, filamentous actin-binding protein present in the sarcomere of muscle. It maintains the actin filaments at a uniform distance form the myosin-containing thick filaments.
Necrosis
Cell death due to irreversible damage characterised by nuclear changes including shrunken, dark, basophilic staining and fragmented nuclei.
Needleman-Wunsch
A dynamic programming algorithm for global sequence alignment. See Smith-Waterman.
Negative autogenous regulation;
negative self-regulation Inhibition of the expression of a gene or set of coordinately regulated genes by the product of the gene or the product of one of the genes.
Negative complementation
Interallelic complementation that permits a mutant subunit to suppress the activity of a wild type subunit in a multimeric protein.
Negative control
Regulation of activity by inhibition.
Negative control system
A mechanism in which a regulatory protein(s) is required to turn off gene expression.
Negative cooperativity
The phenomenon exhibited by some multisubunit proteins in which binding of a ligand or substrate to one subunit imparis binding to another subunit.
Negative feedback
The inhibition of an earlier step in a biochemical pathway by a reduction product.
Negative nitrogen balance
A state in which nitrogen loss is greater than the intake. It occurs due to deficient protein intake, decreased protein digestion, decreased amino acid absorption and increased catabolism or loss of proteins.
Negative regulation
(negative regulators) A term used to describe the regulation of gene expression based on repression of gene expression.
Negative selection
1. A selection process in which cells containing the DNA insert die, whereas those that have not gained an insert survive. The selection is done on replica plates made by transferring a few cells from a colony to a new culture plate. 2. Elimination of self-specific T and B cells during lymphocyte development or in vitro elimination of particular cells by incubating them with specific antibody plus complement.
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