SEARCH · PubMed Health

Results for “Fireflies”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed1991

Sequence analysis of firefly luciferase family reveals a conservative sequence motif.

A conservative sequence motif was extracted from an alignment of the firefly luciferase family. AngR derived from a pathogenic bacterium and acetyl-CoA synthetases derived from two ascomycete fungi were identified as members of the firefly luciferase family by a homology search with the motif and other sequence comparison analyses. The motif sequence shares several characteristics with the phosphate-binding sites of phosphoproteins and nucleotide-binding proteins. A multiple alignment and an unrooted phylogenetic tree were constructed for the investigation of evolutionary relationships within the firefly luciferase family.

Amino Acid Sequence↗

PubMed1985

Cholera toxin, cyclic AMP, and the firefly flash.

Cholera toxin, injected into living fireflies, caused a delayed, non-hormone-dependent activation of adenylate cyclase, an elevation of cyclic AMP levels, and a brilliant persistent glow of the firefly light organ 8-20 hours following injection. During periods of spontaneous flashing, onset of toxin-induced glowing was abrupt and step-like in character, due to a markedly prolonged off-time of individual flashes. These observations provide a striking demonstration of the mechanism of cholera toxin action, and, together with other data, suggest that the initiation of the normal adult firefly flash is mediated through elevation of cyclic AMP levels secondary to the activation of an octopamine-sensitive adenylate cyclase.

Adenylyl Cyclases↗

PubMed1979

[Kinetic properties of highly purified luciferase from fireflies Luciola mingrelica].

Luciferase of the fireflies Luciola mingrelica was isolated from dried lanterns of fireflies and purified by chromatography on DEAE-Sephadex. The homogeneity of the preparation was determined by polyacrylamide gel disc electrophoresis. The molecular weight of the enzyme equal to 45000 was determined by disc electrophoresis in the presence of sodium dodecyl sulfate. The kinetic properties of the enzyme (V and Km for luciferin and ATP) within the pH-range of 7,0--8,5 were studied. The kinetic curves of the pH-dependences of log V and log Km for both substrates are bell-shaped, with a slope equal to 2. At pH optimum (7,7--7,9) the Km values for luciferin and ATP are 6,6 mkM and 0,3 mM, respectively. The properties of luciferase L. m. were compared to those of luciferase from fireflies Phophinus pyralis previously described in literature.

Animals↗

PubMed1978

Comparative studies of firefly pacemakers.

Rhythmic flashing behavior of synchronous flashing fireflies from Malaysia and New Guinea was studied. The "circa second" firefly pacemaker has characteristics analogous to circadian rhythms, such as entrainment, phase shifting, limits of entrainment, fringe entrainment, and effects of the light:dark ratio on phase. The three species studied show different phase-response curves; a light pulse causes a large phase shift in one firefly species (Pteroptyx cribellata) but small phase shifts in others (Pteroptyx malaccae and Luciola pupilla). Comparative studies of the phase angle differences between the animal's flash and the flash of a controlled light source suggest at least two different mechanisms of attaining synchrony: 1) by cycle-to-cycle phase shifting of a stable oscillator; 2) by changing the underlying period (tau) of a variable oscillator.

Adaptation, Physiological↗

PubMed2004

Identification of luciferyl adenylate and luciferyl coenzyme a synthesized by firefly luciferase.

The firefly luciferase reaction intermediate luciferyl adenylate was detected by RP-HPLC analysis when the luciferase reaction was performed under a nitrogen atmosphere. Although this compound is always specified as an intermediate in the light-production reaction, this is the first report of its identification by HPLC in a luciferase assay medium. Under a low-oxygen atmosphere, luciferase can catalyze the synthesis of luciferyl coenzyme A from luciferin, ATP, and coenzyme A, but in air dehydroluciferyl coenzyme A was produced. The luciferase-catalyzed synthesis of these coenzyme A derivatives may be a consequence of the postulated recent evolutionary origin of firefly luciferases from an ancestral acyl-coenzyme A synthetase.

Adenosine Triphosphate↗

PubMed1997

Inactivation of firefly luciferase with N-(iodoacetyl)-N'- (5-sulfo-1-naphthyl)ethylenediamine (I-AEDANS).

N-Iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine (I-AEDANS), a fluorescent reagent that selectively modifies cysteine residues, was demonstrated to irreversibly inhibit native Photinus pyralis luciferase purified from firefly lanterns. Complete inactivation of luciferase activity was accompanied by the blockage of all four cysteine thiols and the concomitant incorporation of 4 mol of N-acetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine (AEDANS) per mole of enzyme. Employing proteolytic digestions of AEDANS-labeled luciferase and reverse-phase-high-performance liquid chromatography (RP-HPLC), seven tagged peptides were isolated. The AEDANS label provided a convenient spectroscopic marker for the identification of the modified peptides. The sequences of the labeled peptides were deduced from electrospray ionization mass spectrometry (ESMS) and N-terminal sequencing. The fluorescent peptides included cysteine residues and spanned sequences composed of amino acids Leu78-Lys85, Thr214-Arg218, Asp224-Arg275, and Gly388-Met396. The luciferin substrate provided substantial protection against luciferase inactivation resulting in a 60-67% decrease in the labeling of all four cysteine thiols. Thus, it does not appear that a specific cysteine mediates the loss of luciferase activity. Additional LC/ESMS studies permitted the identification of 78% of the native luciferase molecule, which, unlike the recombinant protein, was found to contain an acetylated N-terminus. The AEDANS labeling results and the identification of well-defined proteolytic fragments should facilitate future structure-function investigations of the firefly luciferases.

Adenosine Triphosphate↗

PubMedDate not supplied

Circadian regulation of a viral gene promoter in live transgenic mice expressing firefly luciferase.

PURPOSE: This study was conducted to test for possible circadian control of viral infection in live animals using bioluminescence imaging of a firefly luciferase transgene. METHODS: Transgenic mice expressing the firefly luciferase gene under the control of the promoter and enhancer of the human cytomegalovirus major immediate-early gene (CMV::luc) were examined through whole-animal imaging. Mice were crossed with HRS/J hairless albino mice to improve imaging of deep structures. RESULTS: Transgene expression in the extremities and head was elevated around dusk in mice maintained in cycles of light and dark. Signal was also elevated during the animal's night in mice maintained in extended darkness. The viral promoter was induced during the active phase of the circadian locomotor rhythm in several tissues. Both the acinar cells and islets expressed the transgene in dissociated pancreas cultures. CONCLUSIONS: These results suggest that viruses may exploit the circadian system for optimal timing of infection at particular phases in several tissue types.

Animals↗

PubMed1989

Urethane as an inhibitor of the firefly light reaction.

A study has been made to test the hypothesis that general anesthetics such as urethane are able to inhibit light from a firefly reaction mixture. Urethane was found to reduce light emission in a dose-dependent manner, the minimal effective concentration being about 20 mM. Dixon plots gave a Ki value in the range of 175 to 215 mM. Lineweaver-Burk plots showed that urethane increases the apparent Km for ATP and reduces Vmax for the reaction. This is taken to mean that urethane acts as both a competitive and non-competitive inhibitor of the firefly light reaction (mixed-type inhibition).

Animals↗

PubMed2004

Inhibitory effect of lipoic acid on firefly luciferase bioluminescence.

Lipoic acid was found to inhibit the firefly luciferin-luciferase reaction. The inhibition is competitive and is the strongest known (Ki = 0.026 +/- 0.013 microM) compared with other reported inhibitors. Considering the structure-activity correlations, the mechanism of inhibition may originate from the sulfur atom and carboxyl moiety of lipoic acid giving it structural specificity. Subsequent addition of lipoic acid and nitric oxide accelerated the inhibition in vitro, suggesting that lipoic acid may have a functional role in regulating firefly bioluminescence.

Animals↗

PubMed2004

Synthesis of 7'-[123I]iodo-D-luciferin for in vivo studies of firefly luciferase gene expression.

D-(-)-2-(6'-hydroxy-7'-[(123)I]iodobenzothiazolyl)-delta(2)-thiazoline-4-caroxylic acid (7'-[(123)I]iodo-D-luciferin) was synthesized as a novel reporter probe for in vivo studies of firefly luciferase gene expression. 7'-Iodo-D-luciferin, a nonradioactive standard, was synthesized and showed the binding property (K(M)=4.28 microM) similar to that of D-luciferin (2.53 microM) for firefly luciferase in luminescence assay.

Animals↗

PubMed2005

Sperm storage and viability in Photinus fireflies.

In many species females mate with and store sperm from multiple males, and some female insects have evolved multiple compartments for sperm storage. Sperm storage and sperm viability were investigated in two firefly species, Photinus greeni and P. ignitus, which differ in the morphology of the female reproductive tract. Although the primary spermatheca is similar in both species, P. greeni females have an additional, conspicuous outpocketing within the bursa copulatrix whose potential role in sperm storage was investigated in this study. An assay that distinguishes between live and dead sperm was used to examine sperm viability in male seminal vesicles and sperm storage sites within the female reproductive tract. For both Photinus species, sperm from male seminal vesicles showed significantly higher viability compared to sperm from the primary spermatheca of single mated females. In single mated P. greeni females, sperm taken from the channel outpocketing (secondary spermatheca) showed significantly higher viability compared to sperm from the primary spermatheca. This sperm viability difference was not evident in double mated females. There were no significant differences between P. greeni and P. ignitus females in the viability of sperm from the primary spermatheca. These studies contribute to our understanding of post-mating processes that may influence paternity success, and suggest that sexual conflict over control of fertilizations may occur in multiply mated firefly females.

Animals↗

PubMed2006

Expression of firefly luciferase in Candida albicans and its use in the selection of stable transformants.

The infectious yeast Candida albicans is a model organism for understanding the mechanisms of fungal pathogenicity. We describe the functional expression of the firefly luciferase gene, a reporter commonly used to tag genes in many other cellular systems. Due to a non-standard codon usage by this yeast, the CUG codons were first mutated to UUG to allow functional expression. When integrated into the chromosome of C. albicans with a strong constitutive promoter, cells bioluminesce when provided with luciferin substrate in their media. When fused to the inducible promoter from the HWP1 gene, expression and bioluminescence was only detected in cultures conditioning hyphal growth. We further used the luciferase gene as a selection to isolate transformed cell lines from clinical isolates of C. albicans, using a high-density screening strategy that purifies transformed colonies by virtue of light emission. This strategy requires no drug or auxotrophic selectable marker, and we were thus able to generate stable transformants of clinical isolates that are identical to the parental strain in all aspects tested, other than their bioluminescence. The firefly luciferase gene can, therefore, be used as a sensitive reporter to analyze gene function both in laboratory and clinical isolates of this medically important yeast.

Blotting, Southern↗

PubMed1998

Structural basis for the inhibition of firefly luciferase by a general anesthetic.

The firefly luciferase enzyme from Photinus pyralis is probably the best-characterized model system for studying anesthetic-protein interactions. It binds a diverse range of general anesthetics over a large potency range, displays a sensitivity to anesthetics that is very similar to that found in animals, and has an anesthetic sensitivity that can be modulated by one of its substrates (ATP). In this paper we describe the properties of bromoform acting as a general anesthetic (in Rana temporaria tadpoles) and as an inhibitor of the firefly luciferase enzyme at high and low ATP concentrations. In addition, we describe the crystal structure of the low-ATP form of the luciferase enzyme in the presence of bromoform at 2.2-A resolution. These results provide a structural basis for understanding the anesthetic inhibition of the enzyme, as well as an explanation for the ATP modulation of its anesthetic sensitivity.

Adenosine Triphosphate↗

PubMed2000

The role of lysine 529, a conserved residue of the acyl-adenylate-forming enzyme superfamily, in firefly luciferase.

Firefly luciferase catalyzes the highly efficient emission of yellow-green light from the substrates luciferin, Mg-ATP, and oxygen in a two-step process. The enzyme first catalyzes the adenylation of the carboxylate substrate luciferin with Mg-ATP followed by the oxidation of the acyl-adenylate to the light-emitting oxyluciferin product. The beetle luciferases are members of a large family of nonbioluminescent proteins that catalyze reactions of ATP with carboxylate substrates to form acyl-adenylates. Formation of the luciferase-luciferyl-AMP complex is a specific example of the chemistry common to this enzyme family. Site-directed mutants at positions Lys529, Thr343, and His245 were studied to determine the effects of the amino acid changes at these positions on the individual luciferase-catalyzed adenylation and oxidation reactions. The results suggest that Lys529 is a critical residue for effective substrate orientation and that it provides favorable polar interactions important for transition state stabilization leading to efficient adenylate production. These findings as well as those with the Thr343 and His245 mutants are interpreted in the context of the firefly luciferase X-ray structures and computational-based models of the active site.

Adenosine Monophosphate↗

PubMed1991

Membrane-permeable luciferin esters for assay of firefly luciferase in live intact cells.

Five esters of luciferin were synthesized and compared with native luciferin as substrates for firefly luciferase expressed in live intact mammalian cells. The esters themselves were not substrates for purified luciferase, but four were substrates for a purified esterase and all appeared to be hydrolysed to luciferin within mammalian cells. At a substrate concentration of 0.01 mM, the peak luminescence from the cos cells expressing luciferase was up to 6-fold greater with the esters than with unmodified luciferin. At 0.1 mM, the difference between luciferin and the esters was decreased. The kinetics of the luminescent signal with the different luciferin esters varied significantly, indicating possible differences in the rates of uptake, breakdown and enzyme inhibition. The esters did not support luminescence from Escherichia coli cells expressing firefly luciferase, suggesting a lack of appropriate esterase activity in this particular strain. The esters could be useful for the assay of luciferase expression in intact mammalian cells when luciferin levels are limiting, for example in tissues, and in plants. Alternative luciferin derivatives may allow further improvements in sensitivity.

Animals↗

PubMed1995

Regulatory effects of ATP and luciferin on firefly luciferase activity.

ATP and luciferin are not only substrates of firefly luciferase, but can, in addition, modulate its activity. High concentrations of luciferin induce a conformational change of the enzyme that temporarily reduces the catalytic rate. Re-activation takes approx. 20 min and is independent of variation in the concentration of enzyme or ATP, but lengthens with increasing luciferin concentration. High concentrations of albumin reduce this luciferin effect. The kinetic properties of firefly luciferase determined from initial rates and at steady state after 1 min of catalysis have been analysed according to Michaelis-Menten kinetics. There is only one active site for each of the substrates. At steady state the Km and Vmax. values for both substrates are reduced in an uncompetitive manner. Hyperbolic Lineweaver-Burk plots indicate an activation by ATP probably by binding to an allosteric site. A model is presented which incorporates luciferin induced de- and re-activation effects. Experimental conditions to avoid the regulatory effects of substrates during ATP monitoring are proposed.

Adenosine Triphosphate↗

PubMed1996

Firefly luciferase can use L-luciferin to produce light.

L-Luciferin is a competitive inhibitor of firefly luciferase with a K1 between 3 and 4 microM. Furthermore L-luciferin can serve as an alternative substrate for light production. Catalysis of L-luciferin can be observed in the absence of, or at low concentrations of, D-luciferin. The light production from L-luciferin increases slowly (maximal half-time 8 min) to a stable plateau. At low concentrations of enzyme and L-luciferin, maximal light production is about half of that observed at corresponding D-luciferin concentrations. Increasing the concentration of enzyme or L-luciferin reduces the light production relative to that obtained by D-luciferin catalysis. In contrast to the catalysis of D-luciferin the light production from L-luciferin can be effectively stimulated by the addition of PP1 provided that luciferase is premixed with inorganic pyrophosphatase (PP1-ase). A flash is emitted if PP1 is injected into a mixture of luciferase, L-luciferin, ATP and PP1-ase. The system maintains its responsiveness and emits further flashes of about equal duration and intensity upon repeated additions of PP1. It is proposed that PP1 induces a racemization of enzyme-bound L-luciferyl adenylate. The potential usefulness of PP1-dependent intracellular ATP monitoring is discussed. The proposed activation of firefly luciferase by PP1 may be part of the regulation of in vivo flashing.

Animals↗

PubMed1964

THE SPECTRAL DISTRIBUTION OF FIREFLY LIGHT.

The in vivo emission spectra of sixteen species of Jamaican fireflies and four species of American fireflies have been measured with a photoelectric recording spectrometer. A simple technique of stimulation with ethyl acetate vapor was found to elicit bright continuous emission over a period of several minutes. Although the luciferin-luciferase cross-reactions were positive in all cases tested, peak intensity wavelengths show distinct species differences, ranging from 5520 to 5820 A. Widely separated emission peaks arise from the thoracic and abdominal organs respectively in the same animal, the click-beetle, Pyrophorus.

Animals↗