Previous Article | Next Article 
Applied and Environmental Microbiology, July 2005, p. 3427-3432, Vol. 71, No. 7
0099-2240/05/$08.00+0 doi:10.1128/AEM.71.7.3427-3432.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Alternative Luciferase for Monitoring Bacterial Cells under Adverse Conditions
Siouxsie Wiles,
Kathryn Ferguson,
Martha Stefanidou,
Douglas B. Young, and
Brian D. Robertson*
Centre for Molecular Microbiology and Infection, Faculty of Medicine, Imperial College London, Flowers Building, South Kensington, London SW7 2AZ, United Kingdom
Received 22 December 2004/
Accepted 7 January 2005

ABSTRACT
The availability of cloned luciferase genes from fireflies (
luc)
and from bacteria (
luxAB) has led to the widespread use of bioluminescence
as a reporter to measure cell viability and gene expression.
The most commonly occurring bioluminescence system in nature
is the deep-sea imidazolopyrazine bioluminescence system. Coelenterazine
is an imidazolopyrazine derivative which, when oxidized by an
appropriate luciferase enzyme, produces carbon dioxide, coelenteramide,
and light. The luciferase from the marine copepod
Gaussia princeps (
Gluc) has recently been cloned. We expressed the
Gluc gene
in
Mycobacterium smegmatis using a shuttle vector and compared
its performance with that of an existing
luxAB reporter. In
contrast to
luxAB, the
Gluc luciferase retained its luminescence
output in the stationary phase of growth and exhibited enhanced
stability during exposure to low pH, hydrogen peroxide, and
high temperature. The work presented here demonstrated the utility
of the copepod luciferase bioluminescent reporter as an alternative
to bacterial luciferase, particularly for monitoring responses
to environmental stress stimuli.

INTRODUCTION
Bioluminescence is widely distributed in nature, occurring in
a remarkably diverse set of organisms, including bacteria, dinoflagellates,
fungi, fish, insects, shrimp, and squid (
31,
39,
40,
50). Bioluminescence
arises from oxidation of a substrate (a luciferin) by an enzyme
(a luciferase), usually in the presence of molecular oxygen.
Luciferin and luciferase are generic terms as none of the major
classes exhibit sequence homology. While phylogenetic analyses
suggest that bioluminescence has had more than 30 independent
origins, there are five basic luciferin-luciferase systems.
The most widely studied bioluminescence systems are those belonging
to luminous beetles in the family Lampyridae, more commonly
known as fireflies (such as
Photinus pyralis) (
18,
72), and
the luminous bacteria (
Vibrio sp.,
Photobacterium sp., and
Photorhabdus luminescens) (
2,
3,
14,
22,
23,
26,
64). The firefly luminescence
reaction is catalyzed by a monomeric ca. 62-kDa luciferase encoded
by a single gene (
luc) and involves the oxidation of a benzothiazoyl-thiazole
luciferin and ATP, resulting in the production of oxyluciferin,
AMP, CO
2, and light (
18,
47,
51,
72). In contrast, the bacterial
(
lux) luminescence reaction involves the oxidation of a long-chain
aldehyde (RCHO) and reduced flavin mononucleotide, resulting
in the production of oxidized flavin mononucleotide and a long-chain
fatty acid (RCOOH), along with the emission of blue-green light
at 490 nm (
10,
32,
73). The reaction is catalyzed by bacterial
luciferase, a heterodimeric 77-kDa enzyme composed of an alpha
subunit and a beta subunit encoded by the
luxA and
luxB genes,
respectively (
22,
25). Bioluminescence is an excellent reporter
system (recently reviewed in reference
56), a sensitive marker
for microbial detection (
13,
15,
27,
28,
49,
57,
58,
70), a
real-time, noninvasive reporter for measuring gene expression
(
11,
12,
19,
33,
36,
48,
51,
53,
54,
55,
69), and a way to measure
intracellular biochemical function (cell viability) (
1,
4,
5,
16,
17,
27,
28,
29,
30,
34).
The rapid growth of applications of bioluminescence has stimulated research into investigation and exploitation of new bioluminescent systems (44). The most commonly occurring natural bioluminescence system is the deep-sea imidazolopyrazine bioluminescence system that has been found in seven phyla and approximately 90 genera, including copepods, ostracods, cephalopods, and amphipods (66). Coelenterazine is an imidazolopyrazine derivative that acts as the luciferin which, when oxidized by the appropriate luciferase, produces carbon dioxide, coelenteramide, and light (59, 60). One of the most widely studied coelenterazine-catalyzing luciferases is Ruc produced by Renilla reniformans, a sea pansy that displays bioluminescence upon mechanical stimulation. Ruc was first purified and characterized by Matthews et al. (45), and the cDNA was later isolated and expressed in Escherichia coli (42), transgenic plant tissues (46), and mammalian cells (41) and is now commercially available as an assay system (Promega Corporation).
Gaussia princeps is a bioluminescent marine copepod with a 10-mm-long body that lives at depths between 350 and 1,000 m. It emits bioluminescence as a secretion from 30 glands located in the antennas, cephalothorax, thorax, and abdomen in response to mechanical, electrical, or light stimuli (6-8, 38). The release of a luminous bolus from G. princeps is accompanied by rapid swimming that propels the copepod away from the bolus. In this manner, bioluminescence most likely serves as a defense mechanism that startles and blinds dark-adapted predators, providing a glowing decoy to hold the predator's attention while the copepod escapes. The luciferase (Gluc) gene from G. princeps has recently been cloned and shown to oxidize coelenterazine to produce light (9). The Gluc luciferase was subsequently used as a bioluminescent reporter of DNA hybridization and shows promise as a detection reagent in immunoassays (68) and in mammalian cells (65).
The present study was designed to investigate the possible use of the Gluc luciferase as a reporter system in mycobacteria. An estimated 2 billion people are latently infected with Mycobacterium tuberculosis, the causative agent of tuberculosis (21). There are about 8 million new infections per year and 2 million deaths, and many of them are in patients already infected with human immunodeficiency virus. New antituberculosis drugs and better vaccines are urgently needed, and research in these areas is a high priority (63). M. tuberculosis research requires containment level 3 facilities, which coupled with a slow doubling time (nearly 24 h) makes studies using conventional microbiological techniques challenging. In our laboratory (35, 62, 67) and other laboratories (4, 5, 16, 17, 20, 34) extensive use has been made of the bacterial and beetle luciferases as reporter genes in mycobacteria to determine cell numbers and viability. We have shown that the Gluc luciferase is expressed in the fast-growing organism Mycobacterium smegmatis and have characterized its performance under different stress conditions.

MATERIALS AND METHODS
Bacterial strains and growth conditions.
M. smegmatis mc
2 155 (
61) and
E. coli DH5

were used in this
study. Liquid cultures of bacteria were grown with shaking at
200 rpm at 37°C in Luria-Bertani (LB) medium supplemented
with hygromycin (50 µg ml
1) or kanamycin (100 µg
ml
1) as appropriate.
Construction of bioluminescent reporter plasmids.
The plasmids and primers used in this study are shown in Tables 1 and 2. Plasmid pTKmx is a mycobacterium-E. coli shuttle vector that harbors a promoterless xylE reporter gene downstream of a transcriptional terminator (37). The xylE gene was excised from the vector by digestion with the restriction enzymes KpnI and SphI. The luxAB genes derived from Vibrio harveyi were obtained by PCR from plasmid pSMT1 (62) using primers P1 and P2 and directionally cloned using the KpnI and SphI sites in pTKmx to obtain the promoterless reporter plasmid pSKLx. Primers P1 and P2 introduced XbaI and BamHI sites upstream of the luxAB genes and an SpeI site downstream of the luxAB genes. Kanamycin is not the antibiotic of choice when working with mycobacteria as spontaneous mutants frequently arise. For this reason the gene for resistance to the antibiotic hygromycin was obtained by PCR from plasmid pSMT1 (62) using primers P3 and P4 and was directionally cloned using the SphI and HindIII sites in pSKLx to obtain plasmid pSHKLx. In order to obtain high levels of light expression, the 600-bp promoter for the heat shock gene hsp60 was obtained by PCR from M. tuberculosis H37Rv DNA using primers P5 and P6 and was directionally cloned using the XbaI and BamHI sites in pSHKLx to obtain the promoted construct pSHKLx1 (Fig. 1A). The luxAB genes were removed from pSHKLx1 as a BamHI and SphI fragment, and the vector was blunt ended using the Klenow fragment (New England Biolabs, United Kingdom) and dephosphorylated. The 540-bp Gluc luciferase gene from G. princes was excised from plasmid pUC19Gluc (Nanolight Technology, Prolume Ltd., Pinetop, AZ) using EcoRI and XbaI and was blunt ended using the Klenow fragment (Fig. 1B) before ligation into the pSHKLx1 plasmid with luxAB deleted to create pSHKGluc1.
Luminescence assays.
Luminescence measurements were obtained in triplicate at room
temperature using a tube luminometer (Berthold Autolumat LB953).
Luminescence was measured immediately after addition of the
substrate for 10 s using an integration time of 1 s, and the
results were expressed in relative light units (RLU). For bacteria
expressing
Gluc, a 10-mmol liter
1 stock of the substrate
coelenterazine (Nanolight Technology, Prolume Ltd., Pinetop,
AZ) was prepared in methanol for use at a final concentration
of 10 µmol liter
1. All coelenterazine solutions
were stored at 20°C, and working solutions were kept
on ice in the dark during preparation. For bacteria expressing
luxAB a 1% stock of the aldehyde substrate (decanal) was prepared
in ethanol.
Effects of growth phase on the bioluminescence responses of M. smegmatis.
Liquid cultures of bacteria were grown with shaking at 200 rpm at 37°C in LB medium supplemented with hygromycin. Samples were analyzed during the exponential phase (optical density at 600 nm [OD600], 0.5) and during the stationary phase (OD600, 1.2 and 2.5) to determine the effects of the growth phase on bioluminescence. Assays were performed with three independent replicate cultures.
Bioluminescence responses of M. smegmatis to pH.
Assays were performed with exponential-phase cultures (OD600, 0.5). In the wells of a 24-well microtiter plate, 500-µl aliquots of bacterial cells were added to 500-µl aliquots of LB medium acidified using 2 M HCl as previously described (52). Cultures were incubated statically at 37°C and assayed for bioluminescence (as described above) and cell viability (by plating serial dilutions onto Middlebrook 7H11 agar plates supplemented with 10% oleic acid-albumin-dextrose-catalase and hygromycin as appropriate) at 0 and 1 h. Assays were performed twice with three independent replicate cultures.
Bioluminescence responses of M. smegmatis to hydrogen peroxide.
Assays were performed with exponential-phase cultures (OD600, 0.5). In the wells of a 24-well microtiter plate, 500-µl aliquots of bacterial cells were added to 500-µl aliquots of LB medium containing hydrogen peroxide that resulted in final concentrations in the range from 0 to 32 mM. Cultures were incubated statically at 37°C and were assayed for bioluminescence and cell viability at 0 and 90 min. Assays were performed twice with three independent replicate cultures.
Bioluminescence responses of M. smegmatis to heat shock.
Assays were performed with exponential-phase cultures (OD600, 0.5). Bacterial cultures were subjected to 30 min of heat shock at 45°C and 48°C and then incubated at 37°C to recover. Cultures were assayed for bioluminescence prior to heat shock and at regular intervals during recovery. Assays were performed twice with three independent replicate cultures.

RESULTS
Expression of a novel bioluminescence gene in M. smegmatis.
The gene encoding the luciferase enzyme from
G. princeps (
Gluc)
was cloned downstream from an
hsp60 promoter in the mycobacterial
shuttle vector pSHKGluc1 (Fig.
1) and introduced into
M. smegmatis by electroporation. The novel bioluminescence reporter gene
was stably expressed in both
M. smegmatis and
E. coli and catalyzed
a flash reaction in which luminescence decreased approximately
10-fold in the first 5 min (Fig.
2). After this initial decrease
the rate of decreased slowed, and luminescence remained detectable
above the background level after 60 min. The amount of luminescence
was dependent on the concentration of substrate added and followed
a sigmoid curve. At very low coelenterazine concentrations (below
0.5 µmol liter
1) the flash reaction proceeded extremely
fast and the luminescence rapidly decayed to background levels,
while at high concentrations the substrate became saturating.
However, at final concentrations between 0.1 and 10 µmol
liter
1 there was a linear relationship between light
output and coelenterazine concentration (Fig.
3). A final concentration
of coelenterazine of 10 µmol liter
1 was selected
for all further assays. At this concentration, coelenterazine
exhibited background chemiluminescence of approximately 100
RLU ml
1. The background signal was higher in the Middlebrook
7H9 medium commonly used for mycobacterial growth, and in order
to minimize this, LB medium was used throughout the present
study. This is in contrast to the lower background signal of
the aldehyde substrate used by the bacterial luciferase, which
is around 50 RLU ml
1 and is not affected by medium composition.
Gluc bioluminescence correlates with bacterial cell number throughout the exponential and stationary phases of growth in vitro.
To determine the effects of the growth phase on bioluminescence,
M. smegmatis cultures were grown in LB medium, and samples were
taken at various stages during the exponential and stationary
phases of growth. While luminescence from
M. smegmatis expressing
luxAB correlated with cell number during the exponential phase
of growth, when cells entered the stationary phase, the luminescence
decreased (Fig.
4) (
62). Indeed, the RLU/CFU ratios ranged from
0.25 during the mid-exponential phase to 5.81
x 10
5 in
the late stationary phase. In contrast, while the luminescence
of
Gluc-expressing cells was lower than that of
luxAB-expressing
cells during the exponential phase, it correlated with the cell
number throughout both the exponential and stationary phases
of growth (Fig.
4). Indeed, the RLU/CFU ratios remained constant
at ca. 0.004 throughout the experiment.
Gluc bioluminescence is not affected by exposure to low pH.
To determine the effects of pH on bioluminescence and viability,
M. smegmatis cultures were incubated for 1 h in LB medium acidified
with HCl. With the exception of incubation at pH 1.5, which
resulted in a 10-fold decrease in CFU, this treatment was found
to have no effect on the viability of
M. smegmatis, as assessed
by the ability of washed cells to form colonies on Middlebrook
7H11 agar (data not shown) (
52). The luminescence output from
the
luxAB reporter decreased significantly under these conditions,
dropping 10-fold after 1 h of incubation at pH 2.75 and 100-fold
after incubation at pH 1.5 (Table
3). In contrast, this treatment
had no effect on the bioluminescence of
Gluc-expressing cells
(Table
3).
Gluc bioluminescence is not affected by exposure to hydrogen peroxide.
To determine the effects of reactive oxygen species on bioluminescence
and viability,
M. smegmatis cultures were incubated in LB medium
containing various concentrations of hydrogen peroxide. This
treatment was found to have no effect on the viability of
M. smegmatis (data not shown). In contrast, the luminescence of
luxAB-expressing cells was very sensitive to the presence of
hydrogen peroxide; there was an almost 10-fold decrease in light
output after 90 min of incubation with 0.5 mM hydrogen peroxide,
and the number of RLU fell below the limit of detection when
the concentration of hydrogen peroxide was greater than 8 mM
(Fig.
5). Again, the sustained bioluminescence output of
Gluc-expressing
cells paralleled the viability as assessed by CFU (Fig.
5).
Gluc bioluminescence is not affected by heat shock.
M. smegmatis cultures were subjected to 30 min of heat shock
at 45°C and 48°C. Samples were analyzed before the heat
shock, immediately after the heat shock, and after 30 min of
recovery at 37°C. This treatment was found to have no effect
on the viability of
M. smegmatis (data not shown). This was
reflected by the sustained luminescence of
Gluc-expressing cells,
in contrast to the 5- and 10-fold reductions in
luxAB luminescence
after incubation at 45°C and 48°C, respectively (Fig.
6) (
24,
43). The luminescence of
luxAB-expressing cells was
rapidly restored after a 30-min recovery period at 37°C
(Fig.
6).

DISCUSSION
We demonstrated that the copepod
Gluc luciferase can be expressed
in mycobacteria. It catalyzes a flash reaction, but, while luminescence
decays rapidly after addition of the coelenterazine substrate,
it is still detectable above the background level after 60 min.
This compares favorably with both the
luxAB (bacterial) and
luc (firefly) bioluminescence systems (Wiles, unpublished data).
A drawback to the
Gluc system is that the chemiluminescent background
of the coelenterazine substrate is different in different diluent
buffers. While a low background signal was observed with 10
mM coelenterazine in LB medium (10
2 RLU ml
1), the signal
was 100-fold greater in the Middlebrook 7H9 medium commonly
used for culture of the more fastidious organism
M. tuberculosis.
Alternative media (Sauton's medium, for example [
71]) are required
when the
Gluc system is used with
M. tuberculosis.
Experiments with the luxAB reporter system in mycobacteria have shown that there is a strong dependence on changes in the availability of bacterial cofactors under different growth conditions (62, 67). While this is advantageous in signaling a rapid response to the action of some drugs, a sharp decline in luminescence presents a limitation in studying nondividing bacteria in stationary-phase cultures. This is certainly not unique to mycobacteria; in many bacterial species harboring the lux operon, bioluminescence declines when cells enter the stationary phase during in vitro growth (28, 70), and this is most likely due to a decrease in metabolic activity. In contrast, the bioluminescence of Gluc-expressing cells appears to be independent of cofactors that become limited during the stationary phase. Thus, the Gluc reporter provides a correlate of bioluminescence with bacterial number irrespective of the growth phase.
The Gluc system also offers advantages in experiments involving exposure to environmental stress. The ability to survive exposure to low pH and oxidative stress plays an important role in the intracellular survival and pathogenesis of M. tuberculosis, and the heat shock response has been used extensively as a model for studying mycobacterial gene regulation (63). However, in our hands multicopy genes under the control of the hsp60 promoter do not respond to heat shock, presumably because the link with the heat shock regulatory circuit has been broken. Indeed, expression of the luxAB genes under the hsp60 promoter results in the strongest luminescent signal when this expression is compared to the expression with other mycobacterial promoters (Wiles, unpublished results). Exposure of mycobacteria to stress conditions results in rapid dissociation between viability and the output of luminescence from the luxAB reporter. This dissociation is not observed with the Gluc reporter. Given that the two genes are cloned into and expressed in the same vector backbone under control of the same promoter, it is unlikely that this dissociation is due to increased gene expression or enzyme turnover. This difference may again reflect the relative independence of the Gluc reaction from bacterial metabolism or perhaps greater physiological stability of the Gluc luciferase enzyme. The Gluc system may provide a particularly appropriate reporter for studying responses associated with survival under adverse conditions, both during pathogenesis and in the environment.
Conclusions.
In this paper we report the expression of a novel luciferase gene (the Gluc gene) from the marine copepod G. princeps in M. smegmatis that results in detectable luminescence that correlates with viable counts throughout the exponential and stationary phases of bacterial growth under normal conditions in vitro. The work presented here indicated that this luciferase should also be suitable under conditions in which the use of the more traditional bioluminescence genes is limited (for example, in studying bacterial responses to such stresses as oxidative damage and pH). We are currently constructing dual luxAB-Gluc systems with the aim of exploiting the relative advantages and disadvantages of the different luciferase reporters.

ACKNOWLEDGMENTS
This work was supported by the NIH TB Research Unit.
We thank Bruce Bryan (Nanolight Technology, Prolume Ltd., Pinetop, AZ) for the kind gift of plasmid pUC19Gluc and the colenterazine used in this study.

FOOTNOTES
* Corresponding author. Mailing address: Centre for Molecular Microbiology and Infection, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom. Phone: 44 020 7594 3198. Fax: 44 020 7594 3095. E-mail:
b.robertson{at}imperial.ac.uk.


REFERENCES
1 - Arain, T. M., A. E. Resconi, D. C. Singh, and C. K. Stover. 1996. Reporter gene technology to assess activity of antimycobacterial agents in macrophages. Antimicrob. Agents Chemother. 40:1542-1544.[Abstract]
2 - Baldwin, T. O., T. Berends, T. A. Bunch, T. F. Holzman, S. K. Rausch, L. Shamansky, M. L. Treat, and M. M. Ziegler. 1984. Cloning of the luciferase structural genes from Vibrio harveyi and expression of bioluminescence in Escherichia coli. Biochemistry 23:3663-3667.[CrossRef][Medline]
3 - Baldwin, T. O., J. H. Devine, R. C. Heckel, J. W. Lin, and G. S. Shadel. 1989. The complete nucleotide sequence of the lux regulon of Vibrio fischeri and the luxABN region of Photobacterium leiognathi and the mechanism of control of bacterial bioluminescence. J. Biolumin. Chemilumin. 4:326-341.[CrossRef][Medline]
4 - Banaiee, N., M. Bobadilla-del-Valle, P. F. Riska, S. Bardarov, P. M. Small, A. Ponce-de-Leon, W. R. Jacobs, G. F. Hatfull, and J. Sifuentes-Osornio. 2003. Rapid identification and susceptibility testing of Mycobacterium tuberculosis from MGIT cultures with luciferase reporter mycobacteriophages. J. Med. Microbiol. 52:557-561.[Abstract/Free Full Text]
5 - Bardarov, S., H. Dou, K. Eisenach, N. Banaiee, S. U. Ya, J. Chan, W. R. Jacobs, and P. F. Riska. 2003. Detection and drug-susceptibility testing of M. tuberculosis from sputum samples using luciferase reporter phage: comparison with the mycobacteria growth indicator tube (MGIT) system. Diagn. Microbiol. Infect. Dis. 45:53-61.[CrossRef][Medline]
6 - Barnes, A. T., and J. F. Case. 1972. Bioluminescence in the mesopelagic copepod, Gaussia princeps (T. Scott). J. Exp. Mar. Biol. Ecol. 8:53-71.
7 - Bowlby, M. R., and J. F. Case. 1991. Flash kinetics and spatial patterns of bioluminescence in the copepod Gaussia princeps. Mar. Biol. 110:329-336.[CrossRef]
8 - Bowlby, M. R., and J. F. Case. 1991. Ultrastructure and neuronal control of luminous cells in the copepod Gaussia princeps. Biol. Bull. 180:440-446.[Abstract]
9 - Bryan, B. J., and C. S. Szent-Gyorgyi. May 2001. U.S. patent 6232107.
10 - Campbell, A. K. 1989. Living light: biochemistry, function and biomedical applications. Essays Biochem. 24:41-81.[Medline]
11 - Burlage, R. S., G. S. Sayler, and F. Larimer. 1990. Monitoring of naphthalene catabolism by bioluminescence with nah-lux transcriptional fusions. J. Bacteriol. 172:4749-4757.[Abstract/Free Full Text]
12 - Chatterjee, J., and E. A. Meighen. 1995. Biotechnological applications of bacterial bioluminescence (lux) genes. Photochem. Photobiol. 62:641-650.[CrossRef]
13 - Chen, J., and M. W. Griffiths. 1996. Salmonella detection in eggs using Lux+ bacteriophages. J. Food Prot. 59:908-914.
14 - Colepicolo, P., K. Cho, G. O. Poinar, and J. W. Hastings. 1989. Growth and luminescence of the bacterium Xenorhabdus luminescens from a human wound. Appl. Environ. Microbiol. 55:2601-2606.[Abstract/Free Full Text]
15 - Contag, C. H., P. R. Contag, J. I. Mullins, S. D. Spilman, D. K. Stevenson, and D. A. Benaron. 1995. Photonic detection of bacterial pathogens in living hosts. Mol. Microbiol. 18:593-603.[CrossRef][Medline]
16 - Cooksey, R. C., J. T. Crawford, W. R. Jacobs, and T. M. Shinnick. 1993. A rapid method for screening antimicrobial agents for activities against a strain of Mycobacterium tuberculosis expressing firefly luciferase. Antimicrob. Agents Chemother. 37:1348-1352.[Abstract/Free Full Text]
17 - Cooksey, R. C., G. P. Morlock, M. Beggs, and J. T. Crawford. 1995. Bioluminescence method to evaluate antimicrobial agents against Mycobacterium avium. Antimicrob. Agents Chemother. 39:754-756.[Abstract]
18 - de Wet, J. R., K. V. Wood, D. R. Helinski, and M. DeLuca. 1985. Cloning of firefly luciferase cDNA and the expression of active luciferase in Escherichia coli. Proc. Natl. Acad. Sci. USA 82:7870-7873.[Abstract/Free Full Text]
19 - Dorn, J. G., R. J. Frye, and R. M. Maier. 2003. Effect of temperature, pH, and initial cell number on luxCDABE and nah gene expression during naphthalene and salicylate catabolism in the bioreporter organism Pseudomonas putida RB1353. Appl. Environ. Microbiol. 69:2209-2216.[Abstract/Free Full Text]
20 - D'Souza, S., V. Rosseels, O. Denis, A. Tanghe, N. De Smet, F. Jurion, K. Palfliet, N. Castiglioni, A. Vanonckelen, C. Wheeler, and K. Huygen. 2002. Improved tuberculosis DNA vaccines by formulation in cationic lipids. Infect. Immun. 70:3681-3688.[Abstract/Free Full Text]
21 - Dye, C., S. Scheele, P. Dolin, V. Pathania, and R. C. Raviglione. 1999. Global burden of tuberculosisestimated incidence, prevalence, and mortality by country. JAMA 282:677-686.[Abstract/Free Full Text]
22 - Engebrecht, J., K. Nealson, and M. Silverman. 1983. Bacterial bioluminescence: isolation and genetic analysis of functions from Vibrio fischeri. Cell 32:773-781.[CrossRef][Medline]
23 - Engebrecht, J., and M. Silverman. 1984. Identification of genes and gene products necessary for bacterial bioluminescence. Proc. Natl. Acad. Sci. USA 81:4154-4158.[Abstract/Free Full Text]
24 - Escher, A., D. J. O'Kane, J. Lee, and A. A. Szalay. 1989. Bacterial luciferase
ß fusion protein is fully active as a monomer and highly sensitive in vivo to elevated temperature. Proc. Natl. Acad. Sci. USA 86:6528-6532.[Abstract/Free Full Text]
25 - Foran, D. R., and W. M. Brown. 1988. Nucleotide sequence of the luxA and luxB genes of the bioluminescent marine bacterium Vibrio fischeri. Nucleic Acids Res. 16:777.[Free Full Text]
26 - Frackman, S., M. Anhalt, and K. H. Nealson. 1990. Cloning, organization, and expression of the bioluminescence genes of Xenorhabdus luminescens. J. Bacteriol. 172:5767-5773.[Abstract/Free Full Text]
27 - Francis, K. P., D. Joh, C. Bellinger-Kawahara, M. J. Hawkinson, T. F. Purchio, and P. R. Contag. 2000. Monitoring bioluminescent Staphylococcus aureus infections in living mice using a novel luxABCDE construct. Infect. Immun. 68:3594-3600.[Abstract/Free Full Text]
28 - Francis, K. P., J. Yu, C. Bellinger-Kawahara, D. Joh, M. J. Hawkinson, G. Xiao, T. F. Purchio, M. G. Caparon, M. Lipsitch, and P. R. Contag. 2001. Visualizing pneumococcal infections in the lungs of live mice using bioluminescent Streptococcus pneumoniae transformed with a novel gram-positive lux transposon. Infect. Immun. 69:3350-3358.[Abstract/Free Full Text]
29 - Gu, M. B., and S. H. Choi. 2001. Monitoring and classification of toxicity using recombinant bioluminescent bacteria. Water Sci. Technol. 43:147-154.
30 - Gu, M. B., and G. C. Gil. 2001. A multi-channel continuous toxicity monitoring system using recombinant bioluminescent bacteria for classification of toxicity. Biosens. Bioelectron. 16:661-666.[CrossRef][Medline]
31 - Hastings, J. W. 1986. Bioluminescence in bacteria and dinoflagellates, p. 363-398. In A. J. Govindjee, J. Amesz, and D. C. Fork (ed.), Light emission by plants and bacteria. Academic Press, New York, N.Y.
32 - Hastings, J. W., T. O. Baldwin, and M. Z. Nicoli. 1978. Bacterial luciferase: assay purification and properties. Methods Enzymol. 57:135-152.[CrossRef]
33 - Heitzer, A., B. Applegate, S. Kehrmeyer, H. Pinkart, O. F. Webb, T. J. Phelps, D. C. White, and G. S. Sayler. 1998. Physiological considerations of environmental applications of lux reporter fusions. J. Microbiol. Methods 33:45-57.[CrossRef]
34 - Hickey, M. J., T. M. Arain, R. M. Shawar, D. J. Humble, M. H. Langhorne, J. N. Morgenroth, and C. K. Stover. 1996. Luciferase in vivo expression technology: use of recombinant mycobacterial reporter strains to evaluate antimycobacterial activity in mice. Antimicrob. Agents Chemother. 40:400-407.[Abstract]
35 - Kampmann, B., P. O. Gaora, V. A. Snewin, M. P. Gares, D. B. Young, and M. Levin. 2000. Evaluation of human antimycobacterial immunity using recombinant reporter mycobacteria. J. Infect. Dis. 182:895-901.[CrossRef][Medline]
36 - Katayama, M., N. F. Tsinoremas, T. Kondo, and S. S. Golden. 1999. cpmA, a gene involved in an output pathway of the cyanobacterial circadian system. J. Bacteriol. 181:3516-3524.[Abstract/Free Full Text]
37 - Kenney, T. J., and G. Churchward. 1996. Genetic analysis of the Mycobacterium smegmatis rpsL promoter. J. Bacteriol. 178:3564-3571.[Abstract/Free Full Text]
38 - Latz, M. I., M. R. Bowlby, and J. F. Case. 1990. Recovery and stimulation of copepod bioluminescence. J. Exp. Mar. Biol. Ecol. 136:1-22.[CrossRef]
39 - Lee, J. 1989. Bioluminescence, p. 391-417. In K. C. Smith (ed.), The science of photobiology. Plenum Publishing Corp., New York, N.Y.
40 - Lloyd, J. E. 1971. Bioluminescent communication in insects. Annu. Rev. Entomol. 16:97-122.[CrossRef]
41 - Lorenz, W. W., M. J. Cormier, D. J. O'Kane, D. Hua, A. A. Escher, and A. A. Szalay. 1996. Expression of the Renilla reniformans luciferase gene in mammalian cells. J. Biolumin. Chemilumin. 11:31-37.[CrossRef][Medline]
42 - Lorenz, W. W., R. O. McCann, M. Longiaru, and M. J. Cormier. 1991. Isolation and expression of a cDNA encoding Renilla reniformans luciferase. Proc. Natl. Acad. Sci. USA 88:4438-4442.[Abstract/Free Full Text]
43 - Mackey, B. M., D. Cross, and S. F. Park. 1994. Thermostability of bacterial luciferase expressed in different microbes. J. Appl. Bacteriol. 77:149-154.[Medline]
44 - Markova, S. V., S. Golz, L. A. Frank, B. Kalthof, and E. S. Vysotski. 2004. Cloning and expression of cDNA for a luciferase from the marine copepod Metridia longa: a novel secreted bioluminescent reporter enzyme. J. Biol. Chem. 279:3212-3217.[Abstract/Free Full Text]
45 - Matthews, J. C., K. Hori, and M. J. Cormier. 1977. Purification and properties of Renilla reniformans luciferase. Biochemistry 16:85-95.[CrossRef][Medline]
46 - Mayerhofer, R., W. H. R. Langridge, M. J. Cormier, and A. A. Szalay. 1995. Expression of recombinant Renilla luciferase in transgenic plants results in high levels of light emission. Plant J. 7:1031-1038.[CrossRef]
47 - McElroy, W. D. 1951. Properties of the reaction utilising adenosine triphosphate for bioluminescence. J. Biol. Chem. 191:547-557.[Free Full Text]
48 - Mihalcescu, M., W. Hsing, and S. Leibler. 2004. Resilient circadian oscillator revealed in individual cyanobacteria. Nature 430:81-85.[CrossRef][Medline]
49 - Moaz, A., R. Mayr, G. Bresolin, K. Neuhaus, K. P. Francis, and S. Schere. 2002. Sensitive in situ monitoring of a recombinant bioluminescent Yersinia enterocolitica reporter mutant in real time on Camembert cheese. Appl. Environ. Microbiol. 68:5737-5740.[Abstract/Free Full Text]
50 - Nealson, K. H., and J. W. Hastings. 1992. The luminous bacteria, p. 625-639. In A. Balows, H. G. Trüper, M. Dworkin, W. Harder, and K. H. Schleifer (ed.), The prokaryotes: a handbook on the biology of bacteria: ecophysiology, isolation, identification and applications, vol. 1. Springer-Verlag, New York, N.Y.
51 - Neilson, J. W., S. A. Pierce, and R. M. Maier. 1999. Factors influencing expression of luxCDABE and nah genes in Pseudomonas putida RB1353 (NAH7, pUTK9) in dynamic systems. Appl. Environ. Microbiol. 65:3473-3482.[Abstract/Free Full Text]
52 - O'Brien, L. M., S. V. Gordon, I. S. Roberts, and P. W. Andrew. 1996. Response of Mycobacterium smegmatis to acid stress. FEMS Microbiol. Lett. 139:11-17.[CrossRef][Medline]
53 - O'Connell-Rodwell, C. E., S. M. Burns, M. H. Bachmann, and C. H. Contag. 2002. Bioluminescent indicators for in vivo measurements of gene expression. Trends Biotechnol. 20:S19-S23.[CrossRef][Medline]
54 - Park, S. F., G. S. A. B. Stewart, and R. G. Kroll. 1992. The use of bacterial luciferase for monitoring the environmental regulation of expression of genes encoding virulence factors in Listeria monocytogenes. J. Gen. Microbiol. 138:2619-2627.[Abstract/Free Full Text]
55 - Qazi, S. N., E. Counil, J. Morrissey, C. E. Rees, A. Cockayne, K. Winzer, W. C. Chan, P. Williams, and P. J. Hill. 2001. agr expression precedes escape of internalized Staphylococcus aureus from the host endosome. Infect. Immun. 69:7074-7082.[Abstract/Free Full Text]
56 - Roda, A., P. Pasini, M. Mirasoli, E. Michelini, and M. Guardigli. 2004. Biotechnological applications of bioluminescence and chemiluminescence. Trends Biotechnol. 22:295-303.[CrossRef][Medline]
57 - Shaw, J. J., F. Dane, D. Gieger, and J. W. Kloepper. 1992. Use of bioluminescence for detection of genetically engineered microorganisms released into the environment. Appl. Environ. Microbiol. 58:267-273.[Abstract/Free Full Text]
58 - Shaw, J. J., and C. I. Kado. 1986. Development of a Vibrio bioluminescence gene-set to monitor phytopathogenic bacteria during the ongoing disease process in a non-disruptive manner. Bio/Technology 4:560-564.[CrossRef]
59 - Shimomura, O., T. Masugi, F. H. Johnson, and Y. Haneda. 1978. Properties and reaction mechanism of the bioluminescence system of the deep-sea shrimp Oplophorus gracilorostris. Biochemistry 17:994-998.[CrossRef][Medline]
60 - Shimomura, O., and K. Teranishi. 2000. Light-emitters involved in the luminescence of coelenterazine. Luminescence 15:51-58.[CrossRef][Medline]
61 - Snapper, S. B., R. E. Melton, S. Mustafa, T. Kieser, and W. R. Jacobs. 1990. Isolation and characterization of efficient plasmid transformation mutants of Mycobacterium smegmatis. Mol. Microbiol. 4:1911-1919.[Medline]
62 - Snewin, V. A., M.-P. Gares, P. O'Gaora, Z. Hasan, I. N. Brown, and D. B. Young. 1999. Assessment of immunity to mycobacterial infection with luciferase reporter constructs. Infect. Immun. 67:4586-4593.[Abstract/Free Full Text]
63 - Stewart, G. R., B. D. Robertson, and D. B. Young. 2003. Tuberculosis: a problem with persistence. Nat. Rev. Microbiol. 1:97-105.[CrossRef][Medline]
64 - Szittner, R., and E. A. Meighen. 1990. Nucleotide sequence, expression and properties of luciferase coded by lux genes from a terrestrial bacterium. J. Biol. Chem. 265:16581-16587.[Abstract/Free Full Text]
65 - Tannous, B. A., D.-E. Kim, J. L. Fernandez, R. Weissleder, and X. O. Breakefield. 2005. Codon-optimized Gaussia luciferase cDNA for mammalian gene expression in culture and in vivo. Mol. Ther. 11:435-443.
66 - Thomson, C. M., P. J. Herring, and A. K. Campbell. 1997. The widespread occurrence and tissue distribution of the imidazolopyrazine luciferins. J. Biolumin. Chemilumin. 12:87-91.[CrossRef][Medline]
67 - Turner, D. J., S. L. Hoyle, V. A. Snewin, M.-P. Gares, I. N. Brown, and D. B. Young. 2002. An ex vivo culture model for screening drug activity against in vivo phenotypes of Mycobacterium tuberculosis. Microbiology 148:2929-2936.[Abstract/Free Full Text]
68 - Verhaegen, M., and T. K. Christopoulos. 2002. Recombinant Gaussia luciferase. Overexpression, purification, and analytical application of a bioluminescent reporter for DNA hybridization. Anal. Chem. 74:4378-4385.[Medline]
69 - Vollmer, A. C., S. Belkin, D. R. Smulski, T. K. Van Dyk, and R. A. LaRossa. 1997. Detection of DNA damage by use of Escherichia coli carrying recA'::lux, uvrA'::lux, or alkA'::lux reporter plasmids. Appl. Environ. Microbiol. 63:2566-2571.[Abstract]
70 - Wiles, S., S. Clare, J. Harker, A. Huett, D. B. Young, G. Dougan, and G. Frankel. 2005. Organ specificity, colonization and clearance dynamics in vivo following oral challenges with the murine pathogen Citrobacter rodentium. Cell. Microbiol. 6:963-972.
71 - Wiles, S., K. Ferguson, B. D. Robertson, and D. B. Young. 2005. Optimisation of conditions for the use of a novel bioluminescent reporter system in Mycobacterium spp., p. 543-545. In A. Tsuji et al. (ed.), Bioluminescence and chemiluminescence: progress and perspectives. World Scientific, Singapore, Republic of Singapore.
72 - Wood, K. V., Y. A. Lam, H. H. Seliger, and W. D. McElroy. 1989. Complementary DNAs encoding click beetle luciferases can elicit bioluminescence of different colors. Science 244:700-702.[Abstract/Free Full Text]
73 - Ziegler, M. M., and T. O. Baldwin. 1981. Biochemistry of bacterial bioluminescence. Curr. Top. Bioenerg. 12:65-113.
Applied and Environmental Microbiology, July 2005, p. 3427-3432, Vol. 71, No. 7
0099-2240/05/$08.00+0 doi:10.1128/AEM.71.7.3427-3432.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Bachmann, H., Santos, F., Kleerebezem, M., van Hylckama Vlieg, J. E. T.
(2007). Luciferase Detection during Stationary Phase in Lactococcus lactis. Appl. Environ. Microbiol.
73: 4704-4706
[Abstract]
[Full Text]