| cell-free system | <cell culture, molecular biology> Any system in which a normal cellular reaction is reconstituted in the absence of cells for example in vitro translation systems that will synthesise protein from mRNA using a lysate of rabbit reticulocytes or wheat germ. A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (12 Dec 1998) |
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| cell fusion | <biology, embryology> Fusion of two previously separate cells occurs naturally in fertilization and in the formation of vertebrate skeletal muscle, but can be induced artificially by the use of Sendai virus or fusogens such as polyethylene glycol. Fusion may be restricted to cytoplasm or nuclei may fuse as well. A cell formed by the fusion of dissimilar cells is often referred to as a heterokaryon. (26 Mar 1998) |
| cell growth | <cell biology> Usually used to mean increase in the size of a population of cells though strictly should be reserved for an increase in cytoplasmic volume of an individual cell. (26 Mar 1998) |
| cell hybridization | Fusion of two or more dissimilar cells, leading to formation of a synkaryon. (05 Mar 2000) |
| cell hypoxia | A condition of decreased oxygen content at the cellular level. (12 Dec 1998) |
| cell inclusions | The residual elements of the cytoplasm that are metabolic products of the cell, e.g., pigment granules or crystals. Synonym: metaplasm. Storage materials such as glycogen or fat, engulfed material such as carbon or other foreign substances. See: inclusion bodies. (05 Mar 2000) |
| cell junction | <cell biology> Specialised junctions between cells. See: adherens junctions, desmosomes, tight junctions, gap junctions. (26 Mar 1998) |
| cell line | <cell culture> A cell line is a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. Lines differ from cell strains in that they have escaped the Hayflick limit and become immortalised. Some species, particularly rodents, give rise to lines relatively easily, whereas other species do not. No cell lines have been produced from avian tissues and the establishment of cell lines from human tissue is difficult. Many cell biologists would consider that a cell line is by definition already abnormal and that it is on the way towards becoming the culture equivalent of a neoplastic cell. (26 Mar 1998) |
| cell lineage | <cell culture, embryology> The lineage of a cell relates to its derivation from the undifferentiated tissues of the embryo. Committed embryonic progenitors give rise to a range of differentiated cells: in principle it should be possible to trace the ancestry lineage) of any adult cell. (26 Mar 1998) |
| cell line rights | <cell culture> Ownership of a new organism entity. Rulings indicate that any organism that is patentable at all can be patented if it has been manipulated to do something useful. Usually, the rights do not reside with the individual who has supplied the source of the organism, but with the individual or organisation who has made it. (26 Mar 1998) |
| cell line, transformed | Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumour. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals. (12 Dec 1998) |
| cell locomotion | <cell biology> Movement of a cell from one place to another. (26 Mar 1998) |
| cell marker | <cell biology> Biochemical or genetic characteristics which distinguish and discriminate between different cell types. (26 Mar 1998) |
| cell matrix | A fluid cytoplasmic substance filling the interstices of the cytoskeleton. Synonym: cell matrix, cytomatrix. (05 Mar 2000) |
| cell-mediated immunity | <immunology> Immune response that involves effector T lymphocytes and not the production of humoral antibody. Responsible for allograft rejection, delayed hypersensitivity and in defence against viral infection and intracellular protozoan parasites. (26 Mar 1998) |