(n.) A piece of DNA, usually circular, functioning as part of the genetic material of a cell, not integrated with the chromosome and replicating independently of the chromosome, but transferred, like the chromosome, to subsequent generations. In bacteria, plasmids often carry the genes for antibiotic resistance; they are exploited in genetic engineering as the vehicles for introduction of extraneous DNA into cells, to alter the genetic makeup of the cell. The cells thus altered may produce desirable proteins which are extracted and used; in the case of genetically altered plant cells, the altered cells may grow into complete plants with changed properties, as for example, increased resistance to disease.
Example Sentences:
(1) When micF was cloned into a high-copy-number plasmid it repressed ompF gene expression, whereas when cloned into a low-copy-number plasmid it did not.
(2) These eight large plasmids had indistinguishable EcoRI restriction patterns.
(3) The combined analysis of pathogenesis and genetics associated with the salmonella virulence plasmids may identify new systems of bacterial virulence and the genetic basis for this virulence.
(4) On removal of selective pressure, the His+ phenotype was lost more readily than the Ura+ Trp+ markers, with a corresponding decrease in plasmid copy number.
(5) The data on mapping the episomal plasmid integration sites in yeast chromosomes I, III, IV, V, VII, XV are presented.
(6) A beta-adrenergic receptor cDNA cloned into a eukaryotic expression vector reliably induces high levels of beta-adrenergic receptor expression in 2-12% of COS cell colonies transfected with this plasmid after experimental conditions are optimized.
(7) By hybridization studies, three plasmids in two forms (open circular and supercoiled) were detected in the strain A24.
(8) It should be noted that about a half of the plasmids (11 out of 21) belonged to the incompatibility group P-7 which up to the present time was conditional, since was represented by a single plasmid Rms 148.
(9) Since the plasmid-cured strains did not contain DNA sequences homologous to plasmid DNA, the gene for the free-inclusion protein must be encoded in the chromosome.
(10) A total of 28 cell lines were selected for Geneticin - resistance and inoculated into the footpads of syngeneic animals following co-transfection with pSV2neo and genomic DNA, or transfection with plasmid constructs containing neo and the activated Ha-ras oncogene.
(11) Since resistance is mainly mediated by R plasmids, we undertook to investigate the characteristics of R plasmid-determined beta-lactamase in 6 Gram-negative rods.
(12) The 6.6-kb DNA Bam HI fragment containing the resistance gene was cloned with the plasmid vector pIJ699.
(13) Only one E. coli strain, containing two plasmids that encode endo-pectate lyases, exo-pectate lyase, and endo-polygalacturonase, caused limited maceration.
(14) Plasmids containing the inverted repeat alone bound ER, though less efficiently than did plasmids containing the entire sequence.
(15) The plasmid pMucAMucB, constructed from the Haemophilus influenzae vector pDM2, and a similar plasmid, constructed from pBR322, increased the survival after UV irradiation of Escherichia coli AB1157 with the umu-36 mutation and also caused UV-induced mutation in the E. coli strain.
(16) The 105 000 X g supernatant of the reaction mixture, which contained more than 85% of the thiobarbituric acid-reactive substances, did not inactivate the plasmid DNA.
(17) The remainder of the plasmid appeared to be associated with five positioned nucleosomes and two nonnucleosomal, partially protected regions on the bulk of the molecules.
(18) The fifth plasmid contains sequences which are repeated in the yeast genome, but it is not known whether any or all of the ribosomal protein gene on this clone contains repetitive DNA.
(19) Plasmid profiling was used to distinguish strains of lactobacilli inhabiting the digestive tract of piglets and the feces of sows.
(20) One mutant, BS260, was completely noninvasive on HeLa cells and mapped to a region on the 220-kb virulence plasmid in which we had previously localized several avirulent temperature-regulated operon fusions (A.E.
Transduction
Definition:
(n.) The act of conveying over.
Example Sentences:
(1) Preservation of dopaminergic and H1 neurotransmission, probably within the blood barrier, is needed to allow the neuroendocrine transduction of cholinergic inputs, whereas the role of 5-HT neurotransmission remains uncertain.
(2) Adhesion and O2- production were also found to be differentially affected by the NADPH oxidase inhibitor diphenylene iodonium, the sulfhydryl reagent N-ethylmaleimide and the A2 agonist adenosine, indicating that these neutrophil responses have various transductional pathways that also depend on the type of stimulus.
(3) Additionally, the amount of mRNAs for preproenkephalin as well as for the cellular proto-oncogenes c-myc, c-fos and c-H-ras, which are thought to be mediators of intracellular signal transduction, was determined in hippocampus in these same animals.
(4) Our results suggest that multiple receptors and signal transduction pathways are involved in the regulation of the tyrosine hydroxylase gene in the rat adrenal medulla.
(5) This report examines the timing of changes in the contractile potential of the cortical cytoplasm as the oocyte becomes the egg, and in addition, the signal transduction events which induce these changes.
(6) A possible role of the olfactory tubercle in olfactory transduction will also be discussed.
(7) Meta II is the form of photolyzed rhodopsin which binds and activates the visual G-protein (Gt); thus, its relative abundance at equilibrium and temporal stability are important parameters in determining the efficiency of visual signal transduction.
(8) Some of these transductants segregated certain F14 genes, indicating they were carried on self-replicating genetic elements, but others were not cured of F14 markers, even by acridine orange.
(9) This domain is shared by a number of signal transduction proteins including nonreceptor tyrosine kinases such as Abl, Fps, Src, and Src family members, the transforming protein Crk, phospholipase C-gamma 1, PI-3 (phosphatidylinositol) kinase, and guanosine triphosphatase-activating protein (GAP).
(10) In vitro and in vivo studies indicate that endotoxin- or lipopolysaccharide (LPS)-activated macrophages are a principle source of TNF; however, membrane signal transduction and intracellular pathways by which LPS triggers TNF production in macrophages are unclear.
(11) glycoproteins called leukocyte common Ag (CD45), which are involved in phosphotyrosine signal transduction.
(12) These 2 proteins provide a unique model for studying the specificity of signal transduction and gene expression in dopaminoceptive neurons.
(13) The response to both IL-3 and GM-CSF was not additive in the presence of an optimal concentration of one cytokine and titrating concentrations of the other indicating that they may use common receptors and signal transduction mechanisms.
(14) The changes in both mobility and amino-terminal phosphorylation can be reproduced by known activators of protein kinase C (4 alpha-phorbol 12 beta-myristate, dioctanoylglycerol), suggesting that this signal transduction pathway (or related pathways) mediates at least part of these events.
(15) Thus, the gamma 5 and gamma 7 subunits are the first G protein gamma subunits known that could participate in the regulation of widely distributed signal transduction pathways.
(16) It is proposed that the left-right axis in Xenopus, as reflected in cardiac looping, is established early in development, and that proteoglycan synthesis is involved in the transduction of left-right axial information to the cardiac primordia during migration.
(17) In this case, resistance markers were lost when the transductants became Lac- but the derivatives remained copper resistant.
(18) The cyclic adenosine nucleotide pathway is turned off by kinase A activity, whereas the inositol trisphosphate cascade is terminated by kinase C. The data support the concept that desensitization of odorant responses involves phosphorylation of key elements in the transduction cascade.
(19) Interleukin 1 (IL-1) mediates many cellular functions, but the signal transduction mechanisms of its actions are not clearly understood.
(20) This stimulatory effect of kE on the binding of iE to HSF could be inhibited by neomycin, retinal and pertussis toxin, substances which act at different levels of the transduction mechanism following the activation of the receptor and the subsequent triggering of cell biological events (chemotaxis, modification of calcium fluxes).