Previous Article | Next Article 
Journal of Bacteriology, December 2000, p. 6694-6697, Vol. 182, No. 23
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
NorM of Vibrio parahaemolyticus Is an
Na+-Driven Multidrug Efflux Pump
Yuji
Morita,
Atsuko
Kataoka,
Sumiko
Shiota,
Tohru
Mizushima, and
Tomofusa
Tsuchiya*
Department of Microbiology, Faculty of
Pharmaceutical Sciences, Okayama University, Tsushima, Okayama,
700-8530, Japan
Received 19 June 2000/Accepted 15 September 2000
 |
ABSTRACT |
NorM of Vibrio parahaemolyticus
apparently is a new type of multidrug efflux protein, with no
significant sequence similarity to any known transport
proteins. Based on the following experimental results, we conclude that
NorM is an Na+-driven Na+/drug antiporter. (i)
Energy-dependent ethidium efflux from cells possessing NorM was
observed in the presence of Na+ but not of K+.
(ii) An artificially imposed, inwardly directed Na+
gradient elicited ethidium efflux from cells. (iii) The addition of
ethidium to cells loaded with Na+ elicited Na+
efflux. Thus, NorM is an Na+/drug antiporting
multidrug efflux pump, the first to be found in the biological
world. Judging from the similarity of the NorM sequence to those
of putative proteins in sequence databases, it seems that
Na+/drug antiporters are present not only in V. parahaemolyticus but also in a wide range of
other organisms.
| |
INTRODUCTION |
Drug resistance, especially
multidrug resistance, is presently a serious problem in hospitals. Drug
efflux from cells is one of the major mechanisms of drug resistance in
both prokaryotes and eukaryotes (11, 12, 15, 18, 26). Many
drug efflux systems are known to exist in the biological world, and
these transporters can be divided into four families: the major
facilitator (MF) family, the small multidrug resistance (SMR) family,
the resistance nodulation cell division (RND) family, and the ATP binding cassette family (4, 6, 17). Membrane transporters of
the MF family possess 12 to 14 transmembrane domains. Transporters of
the SMR family are rather small and usually possess four transmembrane domains. Transporters of the RND family require multiple components to
function effectively. An electrochemical potential of H+
across cell membranes seems to be the driving force for drug efflux by
members of the MF, SMR, and RND families of transporters (13, 18,
28, 29). ATP is utilized as the energy donor in members of the
ATP binding cassette family of multidrug efflux pumps (3,
26).
The electrochemical potential of H+ across cell membranes
is established mainly by the respiratory chain in aerobic or
facultative anaerobic bacteria. The electrochemical potential of
H+ across the membrane is converted to that of
Na+ by Na+/H+ antiporters (25,
27). Both of the electrochemical potentials of H+ and
Na+ across cell membranes can be utilized to drive solute
uptake in bacterial cells. Solutes are taken up into cells by an
H+/substrate symport mechanism or an
Na+/substrate symport mechanism (19). An
electrochemical potential of H+ is also utilized to drive
extrusion of substrate from cells. Most multidrug efflux pumps in
bacteria are driven by H+, which is a mechanism for
H+/drug antiport (18). However, no
Na+-driven extrusion system for drugs, i.e., no
Na+/drug antiporter, has been reported for bacterial cell
membranes. Although an Na+/Ca2+ exchanger
(16) and an Na+/urea antiporter (9)
have been reported for animal cells, no Na+/drug antiporter
has been reported for animal cells.
Vibrio parahaemolyticus, a slightly
halophilic marine bacterium, is one of the major causes of food
poisoning in Japan and many other countries (14). This
microorganism requires Na+ for its growth (2).
Energy metabolism and energy coupling in membranes of this
microorganism are unique (20). Cells of V. parahaemolyticus possess a primary respiratory
Na+ pump (24) and Na+-coupled
membrane processes, such as an Na+/solute symporter
(21, 22, 24) and an Na+-driven flagellar motor
(1). We thought that Na+/drug antiporters might
exist in this marine organism.
If an Na+/drug antiporter were to exist, it would be
anticipated that (i) Na+ would stimulate drug efflux from
cells, (ii) an artificially imposed Na+ gradient would
elicit drug flux, and (iii) an artificially imposed drug gradient would
elicit Na+ flux. Previously, we cloned and sequenced a gene
encoding the multidrug efflux protein, NorM, from the chromosome of
V. parahaemolyticus (15). The
norM gene was expressed in an Escherichia coli
mutant, KAM3, which lacks the major drug efflux pump AcrAB, and NorM
was characterized (15). Based on its structural features, it
was apparent that NorM is a unique transporter, as it shows no sequence similarity to any other known transporters, although it possesses 12 hydrophobic domains, a characteristic of the MF family (15). In this study we investigated whether the NorM multidrug efflux pump of
V. parahaemolyticus is an
Na+/drug antiporter.
| |
MATERIALS AND METHODS |
Bacterial strains and plasmids.
E. coli KAM3
(15) and HIT-1 (8) and V. parahaemolyticus AQ3334 (24) were used
in this study. Plasmid pMVP36 is a derivative of pBR322 and carries the
norM gene, encoding the NorM multidrug efflux protein,
derived from V. parahaemolyticus AQ3334
(15).
Stimulation of energy-dependent ethidium efflux from cells by
Na+.
E. coli KAM3 and KAM3/pMVP36 cells were
grown separately in L medium (10) supplemented with 40 mM
potassium lactate to the late, exponential phase of growth under
aerobic conditions at 37°C. The cells were then harvested, washed
with a minimal medium (23) (Na+ salts were
replaced with K+ salts), and suspended in the same medium.
Cells were incubated in the minimal medium supplemented with 25 µM
ethidium bromide and 40 µM CCCP
(carbonylcyanide-m-chlorophenylhydrazone) at 37°C for 60 min to load ethidium bromide into the cells. Cells were washed three
times with a solution containing 100 mM morpholinepropanesulfonic acid
(MOPS)-tetramethylammonium hydroxide (pH 7.0), 2 mM MgSO4, and 25 µM ethidium bromide; resuspended in the same buffer
(approximately 0.25 mg of protein/ml); and subjected to fluorescence
measurement at an excitation wavelength of 500 nm and an emission
wavelength of 580 nm. After preincubation at 37°C for 5 min, 10 mM
lactate-tetramethylammonium hydroxide (pH 7.0) was added to initiate
respiration. Then NaCl, LiCl, or KCl (final concentration, 10 mM) was
added to the assay mixture.
Ethidium efflux from cells induced by inwardly directed
artificial Na+ gradient.
E. coli KAM3 and
KAM3/pMVP36 cells were grown as described above. Cells were harvested
at the late-exponential phase of growth and washed twice with 100 mM
potassium phosphate buffer (pH 7.0). To load cells with ethidium, the
cells were incubated in 100 mM potassium phosphate (pH 7.0)
supplemented with 20 µM ethidium bromide, 5 mM 2,4-dinitrophenol, and
5 mM KCN for 60 min at 37°C. The cells were then collected by
centrifugation, washed twice with 100 mM potassium phosphate (pH 7.0)
supplemented with 20 µM ethidium bromide and 2 mM KCN, and suspended
in the same medium (approximately 50 mg of protein/ml). These cells
were then subjected to fluorescence measurements. Ethidium efflux from
cells was initiated by 100-fold dilution of the cell suspension into
100 mM sodium phosphate (pH 7.0) at 25°C.
Efflux of Na+ induced by addition of ethidium to cell
suspension.
E. coli HIT-1/pMVP36 cells were grown in a
minimal medium (23) (Na+ salts were replaced
with K+ salts) supplemented with 40 mM glycerol at 37°C
under aerobic conditions. Cells were harvested at the late-exponential
phase of growth, washed twice with a solution containing 100 mM
MOPS-tetramethylammonium hydroxide (pH 7.0) and 2 mM
MgSO4, and resuspended in the same buffer. A portion (0.5 ml) of this suspension was diluted with 2.5 ml of the same buffer
(approximately 25 mg of protein/ml). NaCl was added to yield a final
concentration of 100 µM. Cells were incubated at 25°C in a plastic
vessel with rapid stirring, and water-saturated N2 gas was
introduced continuously to maintain anaerobic conditions. An
Na+-electrode (Radiometer, Copenhagen, Denmark) and a
reference electrode were put into the vessel. Calibration was carried
out by the addition of known amounts of NaCl. An anaerobic solution of
serine was added (final concentration, 100 µM) to induce
Na+ uptake into cells. Thereafter an anaerobic solution of
ethidium bromide was added to the assay mixture (final concentration,
200 µM). Changes in the Na+ concentration of the assay
medium were monitored with an Na+ electrode.
Efflux of Na+ induced by addition of ethidium to cell
suspension of V. parahaemolyticus.
V.
parahaemolyticus AQ3334 cells were grown in a
minimal medium (20) supplemented with 40 mM potassium
lactate and 1% polypeptone under aerobic conditions at 37°C. Cells
were harvested at the late-exponential phase of growth, washed twice
with a buffer solution containing 200 mM MOPS-tetramethylammonium
hydroxide (pH 7.5) and 5 mM MgSO4, and resuspended in the
same buffer (approximately 15 mg of protein/ml). NaCl was added to
yield a final concentration of 100 µM. Uptake and efflux of
Na+ was monitored with an Na+ electrode as
described above.
| |
RESULTS |
Effect of Na+ on drug efflux via NorM system.
Cells of E. coli KAM3 or KAM3/pMVP36 (pMVP36 carries the
norM gene from V. parahaemolyticus) were first loaded with ethidium, a fluorescent substrate for the NorM system (15), under
deenergized conditions. Thereafter, an energy donor lactate,
a respiratory substrate, was added to initiate drug efflux. In
addition, either NaCl, LiCl, or KCl was added to test its effect on
drug efflux. Addition of lactate to energy-starved cells of E. coli KAM3 did not cause significant ethidium efflux, and further
addition of either KCl, NaCl, or LiCl had no effect (Fig.
1A). Similarly, addition of lactate to
energy-starved cells of E. coli KAM3/pMVP36 caused no
significant ethidium efflux. However, further addition of NaCl (10 mM)
resulted in considerable efflux of ethidium from cells (Fig. 1B, curve
b). Addition of LiCl (10 mM) elicited some ethidium efflux (Fig. 1B,
curve c). Addition of KCl (10 mM) (Fig. 1B, curve a) caused no ethidium
efflux. Thus, ethidium efflux via the NorM system was stimulated by
Na+ or Li+.
View larger version (13K):
[in this window]
[in a new window]
|
FIG. 1.
Effect of monovalent cations on energy-dependent
ethidium efflux via NorM. Energy-starved and ethidium-loaded cells of
E. coli KAM3 and KAM3/pMVP36 were incubated in a buffer
containing 100 mM MOPS-tetramethylammonium hydroxide (pH 7.0), 2 mM
MgSO4, and 25 µM ethidium bromide. After incubation for 5 min at 37°C, 10 mM lactate-tetramethylammonium hydroxide (pH 7.0)
was added to the assay mixture to initiate respiration (first arrow
with Lac). At the time point indicated by the second arrow (with Salt),
either KCl (curve a), NaCl (curve b), or LiCl (curve c) was added to
the assay mixture (final concentration, 10 mM). (A) E. coli
KAM3 cells; (B) E. coli KAM3/pMVP36 cells.
|
|
Ethidium efflux elicited by artificially imposed Na+
gradient.
Ethidium was preloaded into energy-starved cells, and no
energy source was added in the experiment. No significant ethidium efflux from cells was observed with E. coli KAM3 when an
inwardly directed Na+ gradient was imposed (Fig.
2A). However, we observed significant ethidium efflux from KAM3/pMVP36 cells when an inwardly directed Na+ gradient was imposed (Fig. 2B). Imposition of an
increasing Na+ gradient increased the initial velocity of
ethidium efflux (data not shown).
View larger version (12K):
[in this window]
[in a new window]
|
FIG. 2.
Ethidium efflux from cells elicited by an inwardly
directed artificial Na+ gradient. Energy-starved and
ethidium-loaded cells of E. coli KAM3 and KAM3/pMVP36
were suspended (approximately 50 mg of protein/ml) in 100 mM potassium
phosphate buffer (pH 7.0) containing 2 mM KCN and 20 µM ethidium
bromide. An inwardly directed chemical gradient of Na+ was
imposed by a 100-fold dilution of the cell suspension into the assay
medium indicated below at the time point indicated by the arrow. The
assay medium contained either 100 mM potassium phosphate (pH 7.0), 2 mM
KCN, and 20 µM ethidium bromide (curve a) or 100 mM sodium phosphate
(pH 7.0), 2 mM KCN, and 20 µM ethidium bromide (curve b). The assay
was performed at 25°C. (A) E. coli KAM3 cells; (B)
E. coli KAM3/pMVP36 cells.
|
|
Na+ efflux caused by drug influx.
We first
prepared Na+-loaded cells. We demonstrated previously that
imposition of a chemical gradient of substrate, which is taken up with
Na+ via a symport mechanism, elicited Na+
uptake and resulted in accumulation of Na+ in cells
(7). In the current experiment, we utilized serine as
the substrate and E. coli HIT-1/pMVP36 cells as the test
cells. Wild-type E. coli possesses an Na+/serine
symporter (7). E. coli HIT-1 cells lack one of
the major Na+/H+ antiporters
(8). Therefore, the activity of Na+ efflux or
Na+ leakage through the antiporter in this strain is weak.
The strain is thus suitable for measurement of Na+ flux via
another pathway(s) (8). Addition of serine to a cell suspension of HIT-1/pMVP36 under anaerobic conditions induced uptake of
Na+ (Fig. 3). When
Na+ uptake (upward deflection) reached a plateau
level, ethidium was added to the same cell suspension. As anticipated,
we observed Na+ efflux caused by the addition of ethidium
(Fig. 3). Although HIT-1 control cells showed Na+ uptake
elicited by serine, we observed no significant Na+ efflux
when ethidium was added (data not shown). Furthermore, we have tested
many times whether Na+ efflux takes place with cells
possessing NorA or TetA, H+/drug antiporters, or other
H+-coupled transporters and we have never observed
Na+ efflux (data not shown).
View larger version (10K):
[in this window]
[in a new window]
|
FIG. 3.
Na+ efflux from cells elicited by an
inwardly directed ethidium gradient. Energy-starved cells of E. coli HIT-1/pMVP36 were incubated in a buffer consisting of 100 mM
MOPS-tetramethylammonium hydroxide (pH 7.0), 2 mM MgSO4,
and 100 µM NaCl. Flux of Na+ into and out of cells was
measured with an Na+ electrode at 25°C. The first arrow
indicates when an anaerobic solution of serine (final concentration,
100 µM) was added to the cell suspension under anaerobic conditions
to elicit Na+ uptake into cells. The second arrow indicates
when an anaerobic solution of ethidium bromide (final concentration,
200 µM) was added to the assay mixture. Upward deflection represents
the uptake of Na+, and downward deflection represents the
efflux of Na+.
|
|
Na+ efflux elicited by ethidium in V. parahaemolyticus.
We added serine to a cell
suspension of V. parahaemolyticus under
anaerobic conditions, and Na+ uptake was elicited (Fig.
4A and B). The addition of ethidium to
the same cell suspension caused efflux of Na+ (Fig. 4B).
This provides solid evidence for the presence of an Na+/ethidium antiporter in V. parahaemolyticus cells.
View larger version (11K):
[in this window]
[in a new window]
|
FIG. 4.
Na+ efflux from V. parahaemolyticus elicited by ethidium influx.
Energy-starved cells of V. parahaemolyticus
were incubated in a buffer containing 200 mM MOPS-tetramethylammonium
hydroxide (pH 7.0), 5 mM MgSO4, and 100 µM NaCl. Flux of
Na+ into and out of cells was measured with an
Na+ electrode at 25°C. The first arrow indicates the time
point when an anaerobic solution of serine (final concentration, 100 µM) was added to the cell suspension under anaerobic conditions to
elicit Na+ uptake into cells. At the point indicated by the
second arrow, ethidium bromide (final concentration, 200 µM) was
added to the assay mixture. Upward deflection represents the uptake of
Na+, and downward deflection represents the efflux of
Na+.
|
|
| |
DISCUSSION |
Our experimental results presented here support the idea that NorM
mediates Na+/drug antiport. The result that most strongly
supports the idea of Na+/drug antiport by NorM is that
influx of ethidium, a substrate for NorM, elicited efflux of
Na+. So far we have investigated many
Na+-coupled transporters and H+-coupled
transporters. We have never observed Na+ flux elicited
secondarily by H+-coupled transporters. On the other hand,
we have observed a slight H+ flux elicited secondarily by
Na+-coupled transporters (data not shown). This is likely
due to the difference in sensitivity between the H+
electrode and Na+ electrode. The former is much more
sensitive than the latter. We tested whether H+ flux takes
place with NorM. We have never observed H+ flux due to the
NorM system (data not shown). On the other hand, we have detected
H+ flux due to NorA and TetA (data not shown). Thus, it is
clear that NorM is not an H+/drug antiporter.
NorM of V. parahaemolyticus is believed to
be a membrane protein with 456 amino acid residues (15).
Very recently we cloned and sequenced, from chromosomal DNA of V. parahaemolyticus, another gene which seems to encode a
multidrug efflux pump (unpublished data). This system showed a similar
property, requiring Na+ for its activity. Therefore, it is
likely that this new system is also an Na+/drug antiporter.
We found no sequence similarity between this system and NorM. NorM
shares no sequence similarity with any known multidrug efflux protein
found in a sequence database (SwissProt) (15). It has been
proposed that NorM be classified into a new family of transporters
(5). However, NorM shares a high degree of sequence
similarity with uncharacterized putative integral membrane proteins
deduced from genomic DNA sequences in a wide range of archaeabacteria,
eubacteria, and eukaryotes (sequences found in the SwissProt, GenBank,
EMBL, and DDBJ databases). One example is YdhE of E. coli
(15). Our preliminary result supports the idea that YdhE is
also an Na+/drug antiporter (unpublished data). Taken
together, these data suggest that Na+/drug antiporters are
present not only in a marine bacterium but also in a wide range of
other organisms.
| |
ACKNOWLEDGMENTS |
We thank Manuel F. Varela of Eastern New Mexico University for
critically reading the manuscript.
This study was supported in part by a grant from the Ministry of
Education, Science, Sports and Culture of Japan.
| |
FOOTNOTES |
*
Corresponding author. Mailing address: Department of
Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, 700-8530, Japan. Phone and fax:
81-86-251-7957. E-mail:
tsuchiya{at}pharm.okayama-u.ac.jp.
| |
REFERENCES |
| 1.
|
Atsumi, T.,
L. McCarter, and Y. Imae.
1992.
Polar and lateral flagellar motors of marine Vibrio are driven by different ion-motive forces.
Nature
355:182-184[CrossRef][Medline].
|
| 2.
|
Baumann, P., and R. H. W. Schubert.
1984.
Family II. Vibrionaceae veron 1965, 5245AL, p. 516-550.
In
S. T. Williams, M. E. Sharpe, and J. G. Holt (ed.), Bergey's manual of systematic bacteriology, vol. 1. Williams & Wilkins, Baltimore, Md.
|
| 3.
|
Bolhuis, H.,
H. W. van Veen,
D. Molenaar,
B. Poolman,
A. J. Driessen, and W. N. Konings.
1996.
Multidrug resistance in Lactococcus lactis: evidence for ATP-dependent drug extrusion from the inner leaflet of the cytoplasmic membrane.
EMBO J.
15:4239-4245[Medline].
|
| 4.
|
Bolhuis, H.,
H. W. van Veen,
B. Poolman,
A. J. Driessen, and W. N. Konings.
1997.
Mechanisms of multidrug transporters.
FEMS Microbiol. Rev.
21:55-84[CrossRef][Medline].
|
| 5.
|
Brown, M. H.,
I. T. Paulsen, and R. A. Skurray.
1999.
The multidrug efflux protein NorM is a prototype of a new family of transporters.
Mol. Microbiol.
31:394-395[CrossRef][Medline].
|
| 6.
|
Gottesman, M. M., and I. Pastan.
1993.
Biochemistry of multidrug resistance mediated by the multidrug transporter.
Annu. Rev. Biochem.
62:385-427[CrossRef][Medline].
|
| 7.
|
Hama, H.,
T. Shimamoto,
M. Tsuda, and T. Tsuchiya.
1987.
Properties of a Na+-coupled serine-threonine transport system in Escherichia coli.
Biochim. Biophys. Acta
905:231-239[Medline].
|
| 8.
|
Ishikawa, T.,
H. Hama,
M. Tsuda, and T. Tsuchiya.
1987.
Isolation and properties of a mutant of Escherichia coli possessing defective Na+/H+ antiporter.
J. Biol. Chem.
262:7443-7446[Abstract/Free Full Text].
|
| 9.
|
Kato, A., and J. M. Sands.
1998.
Evidence for sodium-dependent active urea secretion in the deepest subsegment of the rat inner medullary collecting duct.
J. Clin. Investig.
101:423-428[Medline].
|
| 10.
|
Lennox, E. S.
1955.
Transduction of linked genetic characters of host by bacteriophage P1.
Virology
1:190-206[CrossRef][Medline].
|
| 11.
|
Levy, S. B.
1992.
Active efflux mechanisms for antimicrobial resistance.
Antimicrob. Agents Chemother.
36:695-703[Free Full Text].
|
| 12.
|
Lewis, K.
1994.
Multidrug resistance pumps in bacteria: variations on a theme.
Trends Biochem. Sci.
19:119-123[CrossRef][Medline].
|
| 13.
|
Mine, T.,
Y. Morita,
A. Kataoka,
T. Mizushima, and T. Tsuchiya.
1998.
Evidence for chloramphenicol/H+ antiport in Cmr (MdfA) system of Escherichia coli and properties of the antiporter.
J. Biochem. (Tokyo)
124:187-193[Abstract/Free Full Text].
|
| 14.
|
Miwatani, T., and Y. Takeda.
1976.
Food poisoning due to Vibrio parahaemolyticus in Japan, p. 22-25.
In
T. Miwatani, and Y. Takeda (ed.), Vibrio parahaemolyticus, a causative bacterium of food poisoning. Saikon Publishing Co., Tokyo, Japan.
|
| 15.
|
Morita, Y.,
K. Kodama,
S. Shiota,
T. Mine,
A. Kataoka,
T. Mizushima, and T. Tsuchiya.
1998.
NorM, a putative multidrug efflux protein, of Vibrio parahaemolyticus and its homolog in Escherichia coli.
Antimicrob. Agents Chemother.
42:1778-1782[Abstract/Free Full Text].
|
| 16.
|
Nicoll, D. A.,
S. Longoni, and K. D. Philipson.
1990.
Molecular cloning and functional expression of the cardiac sarcolemmal Na+-Ca2+ exchanger.
Science
250:562-565[Abstract/Free Full Text].
|
| 17.
|
Nikaido, H.
1994.
Prevention of drug access to bacterial targets: permeability barriers and active efflux.
Science
264:382-388[Abstract/Free Full Text].
|
| 18.
|
Nikaido, H.
1996.
Multidrug efflux pumps of gram-negative bacteria.
J. Bacteriol.
178:5853-5859[Free Full Text].
|
| 19.
|
Poolman, B., and W. N. Konings.
1993.
Secondary solute transport in bacteria.
Biochim. Biophys. Acta
1183:5-39[Medline].
|
| 20.
|
Sakai, Y.,
Y. Tamao,
T. Shimamoto,
H. Hama,
M. Tsuda, and T. Tsuchiya.
1989.
Cloning and expression of the 5'-nucleotidase gene of Vibrio parahaemolyticus in Escherichia coli and overproduction of the enzyme.
J. Biochem. (Tokyo)
105:841-846[Abstract/Free Full Text].
|
| 21.
|
Sarker, R. I.,
W. Ogawa,
M. Tsuda,
S. Tanaka, and T. Tsuchiya.
1994.
Characterization of a glucose transport system in Vibrio parahaemolyticus.
J. Bacteriol.
176:7378-7382[Abstract/Free Full Text].
|
| 22.
|
Sarker, R. I.,
W. Ogawa,
M. Tsuda,
S. Tanaka, and T. Tsuchiya.
1996.
Properties of a Na+/galactose (glucose) symport system in Vibrio parahaemolyticus.
Biochim. Biophys. Acta
1279:149-156[Medline].
|
| 23.
|
Tanaka, S.,
S. A. Lerner, and E. C. Lin.
1967.
Replacement of a phosphoenolpyruvate-dependent phosphotransferase by a nicotinamide adenine dinucleotide-linked dehydrogenase for the utilization of mannitol.
J. Bacteriol.
93:642-648[Abstract/Free Full Text].
|
| 24.
|
Tsuchiya, T., and S. Shinoda.
1985.
Respiration-driven Na+ pump and Na+ circulation in Vibrio parahaemolyticus.
J. Bacteriol.
162:794-798[Abstract/Free Full Text].
|
| 25.
|
Tsuchiya, T., and K. Takeda.
1979.
Extrusion of sodium ions energized by respiration and glycolysis in Escherichia coli.
J. Biochem. (Tokyo)
86:225-230[Abstract/Free Full Text].
|
| 26.
|
van Veen, H. W., and W. N. Konings.
1997.
Drug efflux proteins in multidrug resistant bacteria.
Biol. Chem.
378:769-777[Medline].
|
| 27.
|
West, I. C., and P. Mitchell.
1974.
Proton/sodium ion antiport in Escherichia coli.
Biochem. J.
144:87-90[Medline].
|
| 28.
|
Yerushalmi, H.,
M. Lebendiker, and S. Schuldiner.
1995.
EmrE, an Escherichia coli 12-kDa multidrug transporter, exchanges toxic cations and H+ and is soluble in organic solvents.
J. Biol. Chem.
270:6856-6863[Abstract/Free Full Text].
|
| 29.
|
Zgurskaya, H. I., and H. Nikaido.
1999.
Bypassing the periplasm: reconstitution of the AcrAB multidrug efflux pump of Escherichia coli.
Proc. Natl. Acad. Sci. USA
96:7190-7195[Abstract/Free Full Text].
|
Journal of Bacteriology, December 2000, p. 6694-6697, Vol. 182, No. 23
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Lakhal, F., Bury-Mone, S., Nomane, Y., Le Goic, N., Paillard, C., Jacq, A.
(2008). DjlA, a Membrane-Anchored DnaJ-Like Protein, Is Required for Cytotoxicity of Clam Pathogen Vibrio tapetis to Hemocytes. Appl. Environ. Microbiol.
74: 5750-5758
[Abstract]
[Full Text]
-
Long, F., Rouquette-Loughlin, C., Shafer, W. M., Yu, E. W.
(2008). Functional Cloning and Characterization of the Multidrug Efflux Pumps NorM from Neisseria gonorrhoeae and YdhE from Escherichia coli. Antimicrob. Agents Chemother.
52: 3052-3060
[Abstract]
[Full Text]
-
Matsuo, T., Chen, J., Minato, Y., Ogawa, W., Mizushima, T., Kuroda, T., Tsuchiya, T.
(2008). SmdAB, a Heterodimeric ABC-Type Multidrug Efflux Pump, in Serratia marcescens. J. Bacteriol.
190: 648-654
[Abstract]
[Full Text]
-
Matsuo, T., Hayashi, K., Morita, Y., Koterasawa, M., Ogawa, W., Mizushima, T., Tsuchiya, T., Kuroda, T.
(2007). VmeAB, an RND-type multidrug efflux transporter in Vibrio parahaemolyticus. Microbiology
153: 4129-4137
[Abstract]
[Full Text]
-
Marinova, K., Pourcel, L., Weder, B., Schwarz, M., Barron, D., Routaboul, J.-M., Debeaujon, I., Klein, M.
(2007). The Arabidopsis MATE Transporter TT12 Acts as a Vacuolar Flavonoid/H+-Antiporter Active in Proanthocyanidin-Accumulating Cells of the Seed Coat. Plant Cell
19: 2023-2038
[Abstract]
[Full Text]
-
Durrett, T. P., Gassmann, W., Rogers, E. E.
(2007). The FRD3-Mediated Efflux of Citrate into the Root Vasculature Is Necessary for Efficient Iron Translocation. Plant Physiol.
144: 197-205
[Abstract]
[Full Text]
-
Su, X.-Z., Chen, J., Mizushima, T., Kuroda, T., Tsuchiya, T.
(2005). AbeM, an H+-Coupled Acinetobacter baumannii Multidrug Efflux Pump Belonging to the MATE Family of Transporters. Antimicrob. Agents Chemother.
49: 4362-4364
[Abstract]
[Full Text]
-
Kaatz, G. W., McAleese, F., Seo, S. M.
(2005). Multidrug Resistance in Staphylococcus aureus Due to Overexpression of a Novel Multidrug and Toxin Extrusion (MATE) Transport Protein. Antimicrob. Agents Chemother.
49: 1857-1864
[Abstract]
[Full Text]
-
McAleese, F., Petersen, P., Ruzin, A., Dunman, P. M., Murphy, E., Projan, S. J., Bradford, P. A.
(2005). A Novel MATE Family Efflux Pump Contributes to the Reduced Susceptibility of Laboratory-Derived Staphylococcus aureus Mutants to Tigecycline. Antimicrob. Agents Chemother.
49: 1865-1871
[Abstract]
[Full Text]
-
Otsuka, M., Yasuda, M., Morita, Y., Otsuka, C., Tsuchiya, T., Omote, H., Moriyama, Y.
(2005). Identification of Essential Amino Acid Residues of the NorM Na+/Multidrug Antiporter in Vibrio parahaemolyticus. J. Bacteriol.
187: 1552-1558
[Abstract]
[Full Text]
-
Green, L. S., Rogers, E. E.
(2004). FRD3 Controls Iron Localization in Arabidopsis. Plant Physiol.
136: 2523-2531
[Abstract]
[Full Text]
-
Tokunaga, H., Mitsuo, K., Ichinose, S., Omori, A., Ventosa, A., Nakae, T., Tokunaga, M.
(2004). Salt-Inducible Multidrug Efflux Pump Protein in the Moderately Halophilic Bacterium Chromohalobacter sp.. Appl. Environ. Microbiol.
70: 4424-4431
[Abstract]
[Full Text]
-
Goodman, C. D., Casati, P., Walbot, V.
(2004). A Multidrug Resistance-Associated Protein Involved in Anthocyanin Transport in Zea mays. Plant Cell
16: 1812-1826
[Abstract]
[Full Text]
-
Burse, A., Weingart, H., Ullrich, M. S.
(2004). NorM, an Erwinia amylovora Multidrug Efflux Pump Involved in In Vitro Competition with Other Epiphytic Bacteria. Appl. Environ. Microbiol.
70: 693-703
[Abstract]
[Full Text]
-
He, G.-X., Kuroda, T., Mima, T., Morita, Y., Mizushima, T., Tsuchiya, T.
(2004). An H+-Coupled Multidrug Efflux Pump, PmpM, a Member of the MATE Family of Transporters, from Pseudomonas aeruginosa. J. Bacteriol.
186: 262-265
[Abstract]
[Full Text]
-
Hall, J. L., Williams, L. E.
(2003). Transition metal transporters in plants. J Exp Bot
54: 2601-2613
[Abstract]
[Full Text]
-
Huda, N., Lee, E.-W., Chen, J., Morita, Y., Kuroda, T., Mizushima, T., Tsuchiya, T.
(2003). Molecular Cloning and Characterization of an ABC Multidrug Efflux Pump, VcaM, in Non-O1 Vibrio cholerae. Antimicrob. Agents Chemother.
47: 2413-2417
[Abstract]
[Full Text]
-
Yang, S., Clayton, S. R., Zechiedrich, E. L.
(2003). Relative contributions of the AcrAB, MdfA and NorE efflux pumps to quinolone resistance in Escherichia coli. J Antimicrob Chemother
51: 545-556
[Abstract]
[Full Text]
-
Bruggemann, H., Baumer, S., Fricke, W. F., Wiezer, A., Liesegang, H., Decker, I., Herzberg, C., Martinez-Arias, R., Merkl, R., Henne, A., Gottschalk, G.
(2003). The genome sequence of Clostridium tetani, the causative agent of tetanus disease. Proc. Natl. Acad. Sci. USA
100: 1316-1321
[Abstract]
[Full Text]
-
Rouquette-Loughlin, C., Dunham, S. A., Kuhn, M., Balthazar, J. T., Shafer, W. M.
(2003). The NorM Efflux Pump of Neisseria gonorrhoeae and Neisseria meningitidis Recognizes Antimicrobial Cationic Compounds. J. Bacteriol.
185: 1101-1106
[Abstract]
[Full Text]
-
Braibant, M., Guilloteau, L., Zygmunt, M. S.
(2002). Functional Characterization of Brucella melitensis NorMI, an Efflux Pump Belonging to the Multidrug and Toxic Compound Extrusion Family. Antimicrob. Agents Chemother.
46: 3050-3053
[Abstract]
[Full Text]
-
Jin, J., Guffanti, A. A., Bechhofer, D. H., Krulwich, T. A.
(2002). Tet(L) and Tet(K) Tetracycline-Divalent Metal/H+ Antiporters: Characterization of Multiple Catalytic Modes and a Mutagenesis Approach to Differences in Their Efflux Substrate and Coupling Ion Preferences. J. Bacteriol.
184: 4722-4732
[Abstract]
[Full Text]
-
Rogers, E. E., Guerinot, M. L.
(2002). FRD3, a Member of the Multidrug and Toxin Efflux Family, Controls Iron Deficiency Responses in Arabidopsis. Plant Cell
14: 1787-1799
[Abstract]
[Full Text]
-
Li, L., He, Z., Pandey, G. K., Tsuchiya, T., Luan, S.
(2002). Functional Cloning and Characterization of a Plant Efflux Carrier for Multidrug and Heavy Metal Detoxification. J. Biol. Chem.
277: 5360-5368
[Abstract]
[Full Text]
-
Chen, J., Morita, Y., Huda, M. N., Kuroda, T., Mizushima, T., Tsuchiya, T.
(2002). VmrA, a Member of a Novel Class of Na+-Coupled Multidrug Efflux Pumps from Vibrio parahaemolyticus. J. Bacteriol.
184: 572-576
[Abstract]
[Full Text]
-
Nawrath, C., Heck, S., Parinthawong, N., Metraux, J.-P.
(2002). EDS5, an Essential Component of Salicylic Acid-Dependent Signaling for Disease Resistance in Arabidopsis, Is a Member of the MATE Transporter Family. Plant Cell
14: 275-286
[Abstract]
[Full Text]
-
Miyamae, S., Ueda, O., Yoshimura, F., Hwang, J., Tanaka, Y., Nikaido, H.
(2001). A MATE Family Multidrug Efflux Transporter Pumps out Fluoroquinolones in Bacteroides thetaiotaomicron. Antimicrob. Agents Chemother.
45: 3341-3346
[Abstract]
[Full Text]
-
Nishino, K., Yamaguchi, A.
(2001). Analysis of a Complete Library of Putative Drug Transporter Genes in Escherichia coli. J. Bacteriol.
183: 5803-5812
[Abstract]
[Full Text]
-
Hase, C. C., Fedorova, N. D., Galperin, M. Y., Dibrov, P. A.
(2001). Sodium Ion Cycle in Bacterial Pathogens: Evidence from Cross-Genome Comparisons. Microbiol. Mol. Biol. Rev.
65: 353-370
[Abstract]
[Full Text]
Top
Abstract
Introduction
