| microelements | A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (12 Dec 1998) |
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| microencephaly | Abnormal smallness of the brain. Synonym: micrencephalia, microencephaly. Origin: micro-+ G. Enkephalos, brain (05 Mar 2000) |
| microenvironment | The immediate physical and chemical surroundings of a microorganism. (09 Oct 1997) |
| microerythrocyte | Abnormally small red blood cells, found in some types of anaemia. (18 Nov 1997) |
| microetching technique | A method of roughening the surface of a natural tooth or a dental restoration utilizing a gas-impelled jet of fine abrasive. It enhances the attachment of resin cements or restorative materials to the surface. See: airbrasive technique. (05 Mar 2000) |
| microevolution | Evolution on a molecular level (changes within DNA, i.e. Mutations), an individual organism level (DNA recombination, chromosomal mutations, reproduction, natural selection, etc.), and a population level (genetic drifts, phyletic shifts, founder effects, etc.). (09 Oct 1997) |
| microfarad | <physics> The millionth part of a farad. Origin: Micro- + farad. Source: Websters Dictionary (01 Mar 1998) |
| microfauna | Animals too small to be seen with the naked eye. (09 Oct 1997) |
| microfibril | Basic structural unit of the plant cell wall, made of cellulose in higher plants and most algae, chitin in some fungi and mannan or xylan in a few algae. Higher plant microfibrils are about 10nm in diameter and extremely long in relation to their width. The cellulose molecules are oriented parallel to the long axis of the microfibril in a paracrystalline array, which provides great tensile strength. The microfibrils are held in place by the wall matrix and their orientation is closely controlled by the protoplast. (18 Nov 1997) |
| microfilament | <cell biology> Cytoplasmic filament of F actin (5-7nm) which function in structure and movement in eukaryotic cells. They may be laterally associated with other proteins (tropomyosin, alpha actinin) in some cases and may be anchored to the membrane. Microfilaments are conspicuous in adherens junctions. (14 Oct 1997) |
| microfilament proteins | Filaments which are composed primarily of actin and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell. (12 Dec 1998) |
| microfilaments | The smallest of the cytoskeletal filaments. They are composed chiefly of actin and/or myosin. (12 Dec 1998) |
| microfilaraemia | Infection of the blood with microfilariae. Microfilaraemia caused by Wuchereria bancrofti is characterised by sharp nocturnal periodicity, apparently tied to the nocturnal habits of the vector mosquitoes; in geographic areas where mosquitoes are not strictly night-biters (as in parts of Polynesia), the microfilarial periodicity is modified or absent. See: periodic filariasis. (05 Mar 2000) |
| microfilaria | The prelarval stage of filarioidea in the blood and other tissues of mammals and birds. They are removed from these hosts by blood-sucking insects in which they metamorphose into mature larvae. (12 Dec 1998) |
| microfilarial sheath | The membrane surrounding the embryos of certain blood-borne microfilariae, such as Wuchereria, Brugia, and Loa of humans; thought to be derived from the vitelline membrane. (05 Mar 2000) |