| blue-green bacterium | <organism> Modern term for the blue green algae, prokaryotic cells that use chlorophyll on intracytoplasmic membranes for photosynthesis. The blue green colour is due to the presence of phycobiliproteins. Found as single cells, colonies or simple filaments. In Anabaena, in which the cells are arranged as a filament, heterocysts capable of nitrogen fixation occur at regular intervals. According to the endosymbiont theory Cyanobacteria are the progenitors of chloroplasts. (18 Nov 1997) |
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| blue jay | <zoology> The common jay of the United States (Cyanocitta, or Cyanura, cristata). The predominant colour is bright blue. Source: Websters Dictionary (01 Mar 1998) |
| blue line | A bluish line along the free border of the gingiva, occurring in chronic heavy metal poisoning. (05 Mar 2000) |
| blue naevus | <dermatology> A nonmalignant accumulation of highly pigmented melanocytes deep in the dermis. (16 Dec 1997) |
| blue nevus | A dark blue or blue-black nevus covered by smooth skin and formed by heavily pigmented spindle-shaped or dendritic melanocytes in the reticular dermis. Synonym: Jadassohn-Tieche nevus. (05 Mar 2000) |
| blue oedema | The swelling and cyanosis of an extremity in hysterical paralysis. (05 Mar 2000) |
| blue ointment | A grease-based ointment containing 20% finely divided metallic mercury, formerly widely used for local application to the skin for the destruction of body lice. Risk is associated with transdermal absorption of mercury and a local dermatitis. Synonym: mild mercurial ointment. (05 Mar 2000) |
| blue rubber-bleb nevi | A syndrome characterised by erectile, easily compressible, thin-walled haemangiomatous nodules, widely distributed in the skin and in the alimentary canal, and sometimes in other tissues; lesions in the gut may perforate or cause haemorrhage, and the patient may be anaemic from continual bleeding. (05 Mar 2000) |
| blue rubber bleb nevus syndrome | <radiology> Bean syndrome, sporadic (some autosomal dominant), rubbery, raised blue-black skin nevi (cavernous haemangiomata, 0.1 - 5 cm), GI mucosal haemangiomata, bowel: polypoid filling defects of varying sizes, visceral haemangiomata (by angio) associated with: leukaemia, medulloblastoma, hypernephroma, Mafucci syndrome More info: blue rubber bleb nevus syndrome (12 Dec 1998) |
| blue sclera | (05 Mar 2000) |
| blue shield | A prepaid health insurance plan for costs of physicians' services. (12 Dec 1998) |
| blue spot | A bluish stain on the skin caused by the bites of fleas or lice, especially pediculosis pubis. Synonym: blue spot, tache bleuatre. (05 Mar 2000) |
| blue toe syndrome | <syndrome> Atherothrombotic microembolism of the lower extremities due to recurrent cholesterol embolic 'showers' with painful cyanotic discoloration of the toes and embolism to other sites that completely resolve between attacks. Despite the gangrene-like appearance, blue toes may respond to conservative therapy without amputation. (12 Dec 1998) |
| blue vision | A condition in which all objects appear blue; may temporarily follow cataract extraction. Synonym: blue vision, cyanopia. Origin: cyano-+ G. Opsis, vision (05 Mar 2000) |
| blue white colour selection | <molecular biology, procedure> Method for identifying bacterial clones containing plasmids with inserts. Many modern vectors have their polycloning site within a part of the LacZ gene encoding _ galactosidase, which provides _ complementation in an appropriate mutant E. Coli strain. This means that a re ligated (empty) vector will produce blue colonies when grown on plates containing IPTG and X gal, but colonies with a substantial insert in their plasmid's polycloning site are unable to produce functional _ galactosidase and so produce white colonies. (16 Dec 1997) |