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Home >>Biotechnology Dictionary >> Ecdysone - Encapsulation
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Ecdysone -
a steroid hormone in insects that stimulates moulting and metamorphosis. It actson specific genes, stimulating the synthesis of proteins involved in these bodily changes.
Eclosion - 1. emergence of an adult insect from the pupal stage.
2.beginning of germination of fungal spores.
Electro-blotting - the electrophoretic transfer of macromolecules (DNA, RNA or protein) from a gel, in which they have been separated, to a support matrix, such as a nitrocellulose sheet. A transfer usually used in techniques such as Southern and northern blotting.
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Ecology -
the study of the interactions between organisms and their natural environment, both living and non-living.
Economic trait locus - a locus influencing a trait that a contributes to income. The plural form (economic trait loci) is also abbreviated as ETL.
Electromagnetic spectrum - The range of wavelengths or frequencies over which electromagnetic radiation extends.
electron microscope - a microscope that uses an electron beam focused by magnetic. "lenses."
Electrophoresis - a technique that separates charged molecules - such as DNA, RNA or protein - on the basis of relative migration in an appropriate matrix (such as agarose gel or polyacrylamide gel) subjected to an electric field. See agarose gel electrophoresis; polyacrylamide gel electrophoresis (PAGE); pulsed-field gel electrophoresis (PFGE).
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Ecosystem -
the complex of a living community and its environment, functioning as an ecological unit in nature. cf abiotic factors; biotic factors.
Ecotype - a population or a strain of an organism that is adapted to a particular habitat.
Electrochemical sensor - type of biosensor in which a biological process is harnessed to an electrical sensor system, such as an enzyme electrode. Other types couple a biological event to an electrical one via a range of mechanisms, such as those based on oxygen and pH. See enzyme electrode.
ELISA - a sensitive technique for accurately determining specific molecules in a mixed sample. The amount of protein or is other antigen in a given sample is determined by means of an enzyme catalysed colour change, avoiding both the hazards and expense of radioactive techniques.
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Effector cells -
cells of the immune system that are responsible for cellmediated cytotoxicity.
Effector molecule - a molecule that influences the behaviour of a regulatory molecule, such as a repressor protein, thereby influencing gene expression.
Electroporation - 1. an electrical treatment of cells that induces transient pores, through which DNA can enter the cell.
2. the introduction of DNA or RNA into protoplasts or other cells by the momentary disruption of the cell membrane through exposure to an intense electric field.
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Egg -
1. the fertilised ovum (zygote) in egg-laying animals after it emerges from the body.
2. the mature female reproductive cell in animals and plants.
Elastin - a fibrous protein that is the major constituent of the yellow elasticibres of connective tissue.
Electromagnetic radiation - electromagnetic waves, including ultraviolet (UV), X-rays, and gamma radiation (g rays). Electromagnetic radiation is used to produce mutant cells or organisms, or, in the case of UV, disinfestation and sterilisation, in tissue culture.
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Elongation factors- soluble proteins that are required for polypeptide chain elongation.
Embryo - an immature organism in the early stages of development. In mammals, this occurs in the first months in the uterus. In plants, it is the structure that develops in the megagametophyte, as result of the fertilisation of an egg cell, or without fertilisation. In aseptic cultures, adventitious embryos show polarization, followed by the growth of a shoot from one end and a root from the other end.
Embryo cloning - the creation of identical copies of an embryo by embryo splitting (q.v.) or by nuclear transfer (q.v.) from undifferentiated embryonic cells.
Embryo culture - the culture of embryos on nutrient media.
Embryo multiplication and transfer - the cloning of animal embryos and their subsequent transfer to recipients (via artificial inembryonation (q.v.)). The cloned embryos can be clones of an embryo or of an adult.
Embryo sac - a large thin-walled space within the ovule of the seed plant in which the egg and, after fertilisation, the embryo, develop; the mature female gametophyte in angiosperms. Generally a seven-celled structure. The seven cells are two synergids, one egg cell, three antipodal cells (each with a single haploid nucleus) and one endosperm mother cell with two haploid nuclei.
Embryo sexing - the determination of the sex of an embryo, typically by means of PCR (q.v.) involving amplification from a small sample of embryonic tissue, using primers specific for a locus on the Y chromosome.
Embryo splitting - the splitting of young embryos into several sections, each of which develops into an animal. A form of animal cloning, i.e., of producing animals that are genetically identical. In practice, the number of identicals (identical organisms) that can be produced from a single embryo is less than 10.
Embryo technology - generic name for any modification of mammalian embryos. It encompasses embryo cloning, embryo splitting, in vitro fertilisation, and embryo storage.
Embryogenesis - 1. (general) development of an embryo.
2. (in plants) in vitro formation of plants from plant tissues, through a pathway closely resembling normal embryogeny from the zygote; if this development in culture involves somatic cells and not the zygote, it can be indicated by using the term adventitious embryogenesis or somatic embryogenesis. The generation of embryos has two stages initiation and maturation. Initiation needs a high level of the group of plant hormones called auxins; maturation needs a lower level. Other chemicals have to be at suitable levels. The procedure involves the explanting of a piece of plant tissue and putting it on a high auxin medium, where the cells grow into a mass of callus. This is then transferred to a maturation medium, where the callus starts to initialize organs, ultimately growing a root and a shoot.
Embryoid - an embryo-like body developing in vitro. It forms a complete, self-contained platelet with no vascular connection with the callus. The term embryoid is no longer commonly used.
Embryonic stem cells - cells of the early embryo that can give rise to all differentiated cells, including germ line cells.
Empirical - relating to or based upon practical experience, trial and error, direct observation or observation alone, without benefit of scientific method, knowledge or theory.
Encapsidation - the process by which a virus' nucleic acid is enclosed in a capsid. See capsid; coat protein.
Encapsulating agents - anything which forms a shell around an enzyme or bacterium, although the agents used are usually polysaccharides such as alginate or agar. The agents are inert and allow nutrients and oxygen to diffuse into and out of the sphere readily, and are easy to convert from gel (solid) to sol (liquid) or solution form by altering the temperature or the concentration of ions.
Encapsulationany method of getting something, usually an enzyme or bacterium, into a small package or capsule while it is still working or alive. It is a method for immobilising cells for use in a bioreactor.
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