Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.14.14.3 (luciferase)
 38,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nonsubstrate long-chain aliphatic alcohols, carboxylic acids, and their methyl esters were found to complex reversibly with and stabilize an oxygenated flavin-luciferase intermediate, with alcohols being more effective in stabilizing the intermediate. Dissociation constants for the binding of alcohols to luciferase intermediate are in the order of K8 greater than K10 greater than K12 congruent to K14 where the subscripts represent the numbers of carbon atoms of various alcohols. Thermodynamic activation parameters for the decay of oxygenated flavin-luciferase intermediate complexed with alcohols or aldehydes were determined, and similarities were noted between alcohol and aldehyde complexes. Luciferase intermediate complexes formed with 1-decanol and 1-tetradecanol were isolated at 0 degrees C in neutral phosphate buffer, and both showed absorption properties characteristic of 4a-substituted dihydroflavins. The 1-tetradecanol-intermediate species contained one favin per luciferase molecule. Initially this complex was weakly fluorescent, but upon exposure to 370-nm light it was transformed to a highly fluorescent species. The latter shows a fluorescence excitation peak at 370 nm, and its fluorescence emission (lambda max 505 nm) and quantum yield (0.17) closely correspond to that of bioluminescence in vitro. Both the weakly and the highly fluorescent species exhibit full bioluminescence activities when reacted with decanal.
Biochemistry 1979 Dec 25
PMID:Isolation and properties of bacterial luciferase-oxygenated flavin intermediate complexed with long-chain alcohols. 31 37

Bacterial ATP levels in Escherichia coli cultures were determined by luciferin/luciferase assay. Rapid effects of gentamicin on ATP levels in the cultures were studied, and a dose-dependent accumulation of extracellular ATP was demonstrated. This phenomenon was used to develop a rapid bioassay of gentamicin in clinical serum specimens. The accuracy of the assay, expressed as coefficient of variation over the range 16 to 1 mug/ml, varied between 1.8 and 6.5%, compared to 2.3 to 4.7% for an agar disk diffusion assay. Serum gentamicin concentrations were determined by both methods in 122 serum specimens from 43 patients receiving gentamicin alone or in combination with other antibiotics, and the results were compared (r = 0.942). Determination of gentamicin based on luciferase assay of extracellular ATP in bacterial cultures requires only 10 mul of serum, allowing for capillary sampling, and results are available within 2 h.
Antimicrob Agents Chemother 1978 Dec
PMID:New rapid bioassay of gentamicin based on luciferase assay of extracellular ATP in bacterial cultures. 36 54

Luminescent activity of spheroplasts of the cells of Photobacterium phosphoreum was stimulated by Rb+ and K+ and inhibited by Na+ in the medium. Opposite effects of these ions were observed on the rate of O2 consumption of the spheroplasts through the cytochrome and luciferase electron transfer systems. In vitro activities of NADH-FMN reductase and luciferase were only slightly stimulated by Rb+, K+, and Na+, while Na+ exhibited significant activation of the NADH-oxidizing activity of the cells. The redox level of cytochrome b in the spheroplasts during steady-state respiration in an Na+ medium was more reduced, while that of NAD(P) was more oxidized, than those in an Rb+ or K+ medium. Na+ activates the cytochrome electron transfer system at a point between NADH and cytochrome b, and thus has a stimulative effect on cellular O2 consumption. Rb+ and K+ do not show similar activation, but the cellular NAD(P) was brought to a more reduced level, so that in vivo luminescence is stimulated in an Rb+ or K+ medium.
J Biochem 1977 Dec
PMID:Luminescence and respiratory activities of Photobacterium phosphoreum. II. Control by monovalent cations. 59 51

In previous studies with luminous bacteria of all different species it has been reported that the synthesis of luciferase is autoinducible: during growth at low cell densities synthesis is effectively repressed while after induction, at higher cell densities, the rate of synthesis of enzyme is up to five times the growth rate. In this paper we report on newly isolated strains of Photobacterium leiognathi which show continued luciferase synthesis irrespective of the cell density. The specific synthesis rate may nevertheless differ from the rate of growth and depends on the luciferase content of the inoculated cells. A ratio of 1 was established for cells having a maximum luciferase content varying to a ratio of about 2 for cells that contained only 1% of the maximum.
Arch Microbiol 1977 Dec 15
PMID:Control of luciferase synthesis in a newly isolated strain of Photobacterium leiognathi. 60 41

The interaction of bacterial luciferase from Photobacterium phosphoreum with reduced flavin was investigated using various 8-substituted FMNH2 analogs. Flavins tested were FMNH2 and FMNH2 substituted at the 8 position with HO-, CH3O-, C2H5O-, Cl-, Br-, I-, H2N-, (CH3)HN-, and (ch3)2n. 8-ch30-, c2h5o-, cl-, and Br-FMNH2 showed luminescent activity in the luciferase reaction with emission peaks at various wavelengths. 8-HO- and I-FMNH2 were competitive inhibitors toward FMNH2 in the luminescent reaction. 8-Amino analogs of FMNH2 showed no luminescent or inhibitor activity. The dissociation constant of the luciferase-FMNH2 analog complex was determined kinetically as a substrate or inhibitor constant. A contribution of the imino group at position 5 in the isoalloxazine ring to the FMNH2 binding to luciferase was suggested by a Hammett plot of the dissociation constants.
J Biochem 1978 Dec
PMID:Studies on luciferase from Photobacterium phosphoreum. XI. Interaction of 8-substituted FMNH2 with luciferase. 73 95

We optimized conditions for determination of adenosine-5'-triphosphate (ATP) and creatine phosphate from plasma extracted with ethanol/water (96/4 by vol). The procedures utilize the firefly luciferin/luciferase reaction, the bioluminescence being measured with a Du Pont Biometer. ATP is quantitated directly and creatine phosphate is quantitated by reaction with creatine kinase and ADP, after plasma ATP is removed by incubation with the enzyme apyrase. The method is applied to plasma from humans, rabbits, and rats, and possible clinical applications are discussed.
Clin Chem 1977 Dec
PMID:Microdetermination of plasma ATP and creatine phosphate concentrations with a luminescence biometer. 92 76

Isolation of bacteria from the luminous organ of the fish Monocentris japonica has revealed that the organ contains a pure culture of luminous bacteria. For the four fish examined, all contained Photobacterium fischeri as their luminous bacterial symbiont. This is the first time that P. fischeri has been identified in a symbiotic association. A representative isolate (MJl) of the light organ population was selected for in vivo studies of its luminous system. Several physiological features suggest adaptation for symbiotic existence. First, MJl has been shown to produce and respond to an inducer of luciferase that could accumulate in the light organ. Secondly, the specific activity of light production was seen to be maximal under low, growth-limiting concentrations of oxygen. Thirdly, unlike another luminous species (Beneckea harveyi), synthesis of the light production system of these bacteria is not catabolite repressed by glucose--a possible source of nutrition in the light organ. Fourthly, when grown aerobically on glucose these bacteria excrete pyruvic acid into the medium. This production of pyruvate is a major process, accounting for 30-40% of the glucose utilized and may serve as a form of regulatory and nutritional communication with the host.
Biol Bull 1976 Dec
PMID:Symbiotic association of Photobacterium fischeri with the marine luminous fish Monocentris japonica; a model of symbiosis based on bacterial studies. 101 67

The human CD34 hematopoietic stem cell antigen is a highly glycosylated type 1 membrane protein of unknown function. CD34 is expressed on 1% to 4% of bone marrow cells, including pluripotent stem cells and committed progenitors of each hematopoietic lineage. CD34 has also been shown to be expressed on the small vessel endothelium of a variety of tissues and on a subset of bone marrow stromal cells. We have chosen to use the human CD34 gene as model to examine the transcription factors and cis-elements required for stem cell/progenitor cell-specific gene regulation. We show here that the CD34 gene is transcriptionally regulated in tissue culture cells. Using a luciferase reporter gene, we have isolated and characterized an active CD34 promoter. A CD34-luciferase construct, containing 4.5 kb of 5' flanking DNA from a CD34 genomic clone, was 30-fold more active in CD34+ tissue culture cells than in HeLa cells. Sequences from the 3' end of the CD34 gene were shown to have enhancing activity in CD34+ T-lymphoblastic RPMI-8402 cells and not in CD34- U937 cells or in nonhematopoietic HeLa cells. We also show that a cytidine-guanosine island in the 5' end of the CD34 gene is heavily methylated in two CD34- hematopoietic cell lines and demethylated in two CD34+ cell lines. Analysis of the CD34 promoter should result in the identification of stem cell/progenitor cell-specific transcription factors and should provide a means to direct the expression of heterologous genes in hematopoietic stem cells and progenitors.
Blood 1992 Dec 15
PMID:The human CD34 hematopoietic stem cell antigen promoter and a 3' enhancer direct hematopoietic expression in tissue culture. 128 88

Synthesis and activity of the enzymatic equivalent of the sodium pump, Na,K-ATPase, are regulated by thyroid hormone in responsive tissues. The purpose of this study was to determine whether triiodothyronine (T3) regulates the level of the messenger RNA (mRNA) coding for Na,K-ATPase alpha- and beta-subunits in the heart. The expression of Na,K-ATPase mRNAs in in vitro myocardial cells was directly assayed by Northern and slot blot hybridization using Na,K-ATPase alpha- and beta-isoform-specific cDNA probes. Exposure of cultured neonatal rat cardiocytes to 10(-8) M T3 resulted in 1) threefold to fourfold increase in alpha 1- and beta 1-mRNA accumulation, with a maximum elevation at 48 hours, 2) sevenfold increase in alpha 2-mRNA accumulation with a peak elevation at 72 hours, and 3) transient threefold increase in alpha 3-mRNA within the first 24 hours followed by a deinduction thereafter. The increase in alpha 1-mRNA accumulation by T3 occurred over the physiological T3 concentration range with an EC50 of 5 x 10(-10) M. This was associated with a twofold increase in alpha 1-subunit protein accumulation and an increase in Na,K-ATPase transport activity. The half-life of alpha 1-mRNA analyzed by actinomycin D chase was less than 3 hours and was not affected by T3. Transfection experiments with the luciferase reporter gene revealed that thyroid hormone response sequences are located within the 5'-flanking regions of each alpha-isoform gene.(ABSTRACT TRUNCATED AT 250 WORDS)
Circ Res 1992 Dec
PMID:Regulation of Na,K-ATPase gene expression by thyroid hormone in rat cardiocytes. 133 Mar 58

We constructed mercury resistance operon-luciferase (mer-lux) transcriptional fusion plasmids to evaluate in vivo gene expression rates of the mer structural gene promoter (PTPCAD) of transposon Tn21. In vivo gene expression kinetics corresponded well with those previously determined in vitro, yielding an apparent K0.5 for Hg(II)-stimulated induction by MerR of 9.3 x 10(-8) M with the same ultrasensitive threshold effect seen in vitro. We also used the mer-lux fusions to elucidate subtle variations in promoter activity brought about by altered superhelicity. Binding of inducer [Hg(II)] to the transcriptional activator MerR is known to result in DNA distortion and transcriptional activation of the mer operon; it has recently been demonstrated that this distortion is a consequence of MerR-Hg(II)-induced local DNA unwinding to facilitate RNA polymerase open complex formation at PTPCAD. Since negative supercoiling results in DNA unwinding similar to this MerR activation, we hypothesized that a global increase in plasmid supercoiling would facilitate MerR-mediated activation and compromise MerR-mediated repression, while removal of plasmid supercoils would compromise MerR's ability to induce transcription and facilitate its ability to repress transcription. Indeed, we found that increased negative supercoiling results in increased gene expression rates and decreased supercoiling results in reduced gene expression rates for the induced, repressed, and derepressed conditions of PTPCAD. Thus, luciferase transcriptional fusions can detect subtle variations in initial rates of gene expression in a real-time, nondestructive assay.
J Bacteriol 1992 Dec
PMID:A mer-lux transcriptional fusion for real-time examination of in vivo gene expression kinetics and promoter response to altered superhelicity. 133 70


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