| L | 1. <abbreviation> Left (e.g., left eye); lumbar vertebra (L1 to L5). 2. Symbol for inductance; litre; leucine; linking number. 3. Used with a lower case letter, plus sign, subscript letter, or subscript plus sign as a symbol for various doses of toxin. 4. <prefix> Levorotatory, a prefix indicating a chemical compound to be structurally (sterically) related to l-glyceraldehyde. Compare: d-. (21 Jun 2000) |
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| L cell | <cell biology> A series of mouse methylcholanthrene induced sarcoma cell line maintained in culture since the 1950s. The cells were isolated from a strain (c3h) of mouse fibroblasts grown in tissue culture. They are employed for their ability to support replication of many types of viruses. (25 Jun 1999) |
| L chain | <immunology> Although light chains are found in many multimeric proteins, L chain usually refers to the light chains of immunoglobulins. These are of 22 kD and of one of two types, kappa or lambda. A single immunoglobulin has identical light chains (2 kappa or 2 lamda). Light chains have one variable and one constant region. There are isotype variants of both kappa and lamda. (25 Jun 1999) |
| L doses | A group of terms that indicate the relative activity or potency of diphtheria toxin; the L dose's are distinctly different from the minimal lethal dose and minimal reacting dose, inasmuch as the latter two represent the direct effects of toxin, whereas the L dose's pertain to the combining power of toxin with specific antitoxin. Origin: "L" for limes (05 Mar 2000) |
| L form | L-forms are bacterial spheroplasts or protoplasts originating from normal bacteria following partial (spheroplasts) or complete (protoplasts) removal of the cell wall. The formation of L-forms can be either spontaneous, occuring during certain phase of growth, or artificial due to suppression of the rigid cell wall by stimuli such as enzymes, heat-shock, or special L form induction medium etc. Bacterial genera from which L-forms have been derived include: Agrobacterium, Bacillus, Bacterodes, Bartonella, Bordetella, Brucella, Clostridium, Corynebacterium, Erysipelothrix, Escherichia, Flavobacterium, Haemophilus, Listeria, Neisseria, Proteus, Pseudomonas, Salmonella, Sarcina, Serratia, Shigella, Staphylococcus, Streptobacillus, Streptococcus, and Vibrio. (14 Oct 1997) |
| l forms | Bacterial variants, unable to form a complete cell wall, which are formed in cultures by various bacteria; granules (l bodies) appear, unite, and grow into amorphous bodies which multiply and give rise to bacterial cells morphologically indistinguishable from the parent strain. (12 Dec 1998) |
| L myc | <oncogene> Relative of the myc proto-oncogene overexpressed in lung carcinoma. (18 Nov 1997) |
| L ring | <microbiology> Outermost ring of the basal part of the bacterial flagellum in gram-negative bacteria. It may serve as a bush to anchor the flagellum relative to the lipopolysaccharide layer. (18 Nov 1997) |
| L+ dose | The limes tod dose of diphtheria toxin, i.e., the smallest amount of toxin that, when mixed with one unit of antitoxin and injected subcutaneously into a 250-g guinea pig, results in death of the animal within 96 hours (based on the average in a series); on theoretical grounds, one might expect that the difference between the L+ and L0 dose's would be identical to 1 MLD, but this is not so in actual practice; with various toxic filtrates, the difference may range from several to more than 100 MLD's, indicating that the toxin-antitoxin combination is not a firm chemical union that occurs in constant proportions. (05 Mar 2000) |
| L-2,3,4,5-tetrahydrodipicolinate succinyl coenzyme A succinyltransferase | <enzyme> Catalyses conversion of l-2,3,4,5-tetrahydrodipicolinate to n-succinyl-2-amino-6-oxo-l-pimelate Registry number: EC 2.3.1.- Synonym: dapd gene product, thdpa-st (26 Jun 1999) |
| L-2-hydroxyacid oxidase | <enzyme> Consider also glycollate oxidase EC 1.1.3.1 Chemical name: oxidase, l-2-hydroxy acid Registry number: EC 1.1.3.15 Synonym: l-alpha-hydroxy acid oxidase, lactate oxygen oxidoreductase (26 Jun 1999) |
| L-3,4-dihydroxy-2-butanone-4-phosphate synthase | <enzyme> Catalyses the conversion of d-ribulose 5-phosphate to l-3,4-dihydroxy-2-butanone-4-phosphate plus formate derived from carbon 4 of ribulose 5-p Registry number: EC 5.4.- Synonym: dbp synthase (26 Jun 1999) |
| L-alpha-glycerol-phosphate oxidase | <enzyme> Uses molecular oxygen; forms hydrogen peroxide and dehydroxyacetonephosphate Registry number: EC 1.1.3.- Synonym: glycerolphosphate oxidase (26 Jun 1999) |
| l-alpha-narcotine | <chemical> A naturally occurring opium alkaloid that is a centrally acting antitussive agent. Pharmacological action: antitussive agents. Chemical name: 1(3H)-Isobenzofuranone, 6,7-dimethoxy-3-(5,6,7,8-tetrahydro-4-methoxy-6-methyl-1,3-dioxolo(4,5-g)isoquinolin-5-yl)-, (S-(R*,S*))- (12 Dec 1998) |
| L-aminoadipate saemialdehyde dehydrogenase | <enzyme> Degrades saccharopine, enzyme defect in saccharopinuria Registry number: EC 1.2.1.31 Synonym: alpha-aminoadipate reductase system, 2-aminoadipate reductase, aminoadipate-saemialdehyde dehydrogenase, alpha-aminoadipate reductase (26 Jun 1999) |