Role of calcium in the efflux system of Escherichia coli

Ana Martins, Lisa MacHado, Susana Costa, Pedro Cerca, G. Spengler, Miguel Viveiros, Leonard Amaral

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Efflux of antibiotics by Escherichia coli AG100 is performed by a variety of efflux pumps, ensuring survival of the bacterium in widely diverse media. At pH 5, efflux is independent of metabolic energy during the period of time the assay is conducted; at pH 8 it is totally dependent upon metabolic energy. Because calcium ions (Ca2+) are important for membrane transport channels and the activity of ATPases that provide energy functions, the role of Ca2+ in the extrusion of an efflux pump substrate under conditions that challenge the bacterium was investigated. Real-time accumulation and efflux of ethidium bromide (EtBr) by E. coli K-12 AG100 strain [argE3 thi-1 rpsL xyl mtl Δ(gal-uvrB) supE44] was determined by a semi-automated fluorometric method in the presence and absence of Ca2+ and agents that are known to inhibit access of calcium to enzymes that provide energy. Chlorpromazine (CPZ), an inhibitor of calcium binding to proteins (calcium-dependent enzymes), and ethylene diamine tetra-acetic acid (EDTA), a chelator of Ca2+, increased accumulation and efflux of EtBr at pH 8 but not at pH 5. Ca 2+ reverses these effects when the assay is conducted at pH 8. In conclusion, the activity of the efflux pump system of E. coli is dependent upon metabolic energy at pH 8. Because at pH 8 hydrolysis of ATP is favoured and contributes protons for activation of the AcrAB-TolC efflux pump, CPZ is suspected of having its effects on accumulation/efflux of EtBr by indirectly affecting ATPase activity that is dependent upon Ca2+.

Original languageEnglish
Pages (from-to)410-414
Number of pages5
JournalInternational Journal of Antimicrobial Agents
Volume37
Issue number5
DOIs
Publication statusPublished - May 2011

Fingerprint

Escherichia coli
Calcium
Ethidium
Chlorpromazine
Adenosine Triphosphatases
Bacteria
Calcium-Binding Proteins
Diamines
Enzymes
Chelating Agents
Ion Channels
Acetic Acid
Protons
Hydrolysis
Adenosine Triphosphate
Ions
Anti-Bacterial Agents

Keywords

  • Calcium ions
  • Chlorpromazine
  • Efflux pumps
  • Phenothiazine

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)

Cite this

Role of calcium in the efflux system of Escherichia coli. / Martins, Ana; MacHado, Lisa; Costa, Susana; Cerca, Pedro; Spengler, G.; Viveiros, Miguel; Amaral, Leonard.

In: International Journal of Antimicrobial Agents, Vol. 37, No. 5, 05.2011, p. 410-414.

Research output: Contribution to journalArticle

Martins, A, MacHado, L, Costa, S, Cerca, P, Spengler, G, Viveiros, M & Amaral, L 2011, 'Role of calcium in the efflux system of Escherichia coli', International Journal of Antimicrobial Agents, vol. 37, no. 5, pp. 410-414. https://doi.org/10.1016/j.ijantimicag.2011.01.010
Martins, Ana ; MacHado, Lisa ; Costa, Susana ; Cerca, Pedro ; Spengler, G. ; Viveiros, Miguel ; Amaral, Leonard. / Role of calcium in the efflux system of Escherichia coli. In: International Journal of Antimicrobial Agents. 2011 ; Vol. 37, No. 5. pp. 410-414.
@article{5ecd34b67c3d4f05815ac1f9c3aa9ee4,
title = "Role of calcium in the efflux system of Escherichia coli",
abstract = "Efflux of antibiotics by Escherichia coli AG100 is performed by a variety of efflux pumps, ensuring survival of the bacterium in widely diverse media. At pH 5, efflux is independent of metabolic energy during the period of time the assay is conducted; at pH 8 it is totally dependent upon metabolic energy. Because calcium ions (Ca2+) are important for membrane transport channels and the activity of ATPases that provide energy functions, the role of Ca2+ in the extrusion of an efflux pump substrate under conditions that challenge the bacterium was investigated. Real-time accumulation and efflux of ethidium bromide (EtBr) by E. coli K-12 AG100 strain [argE3 thi-1 rpsL xyl mtl Δ(gal-uvrB) supE44] was determined by a semi-automated fluorometric method in the presence and absence of Ca2+ and agents that are known to inhibit access of calcium to enzymes that provide energy. Chlorpromazine (CPZ), an inhibitor of calcium binding to proteins (calcium-dependent enzymes), and ethylene diamine tetra-acetic acid (EDTA), a chelator of Ca2+, increased accumulation and efflux of EtBr at pH 8 but not at pH 5. Ca 2+ reverses these effects when the assay is conducted at pH 8. In conclusion, the activity of the efflux pump system of E. coli is dependent upon metabolic energy at pH 8. Because at pH 8 hydrolysis of ATP is favoured and contributes protons for activation of the AcrAB-TolC efflux pump, CPZ is suspected of having its effects on accumulation/efflux of EtBr by indirectly affecting ATPase activity that is dependent upon Ca2+.",
keywords = "Calcium ions, Chlorpromazine, Efflux pumps, Phenothiazine",
author = "Ana Martins and Lisa MacHado and Susana Costa and Pedro Cerca and G. Spengler and Miguel Viveiros and Leonard Amaral",
year = "2011",
month = "5",
doi = "10.1016/j.ijantimicag.2011.01.010",
language = "English",
volume = "37",
pages = "410--414",
journal = "International Journal of Antimicrobial Agents",
issn = "0924-8579",
publisher = "Elsevier",
number = "5",

}

TY - JOUR

T1 - Role of calcium in the efflux system of Escherichia coli

AU - Martins, Ana

AU - MacHado, Lisa

AU - Costa, Susana

AU - Cerca, Pedro

AU - Spengler, G.

AU - Viveiros, Miguel

AU - Amaral, Leonard

PY - 2011/5

Y1 - 2011/5

N2 - Efflux of antibiotics by Escherichia coli AG100 is performed by a variety of efflux pumps, ensuring survival of the bacterium in widely diverse media. At pH 5, efflux is independent of metabolic energy during the period of time the assay is conducted; at pH 8 it is totally dependent upon metabolic energy. Because calcium ions (Ca2+) are important for membrane transport channels and the activity of ATPases that provide energy functions, the role of Ca2+ in the extrusion of an efflux pump substrate under conditions that challenge the bacterium was investigated. Real-time accumulation and efflux of ethidium bromide (EtBr) by E. coli K-12 AG100 strain [argE3 thi-1 rpsL xyl mtl Δ(gal-uvrB) supE44] was determined by a semi-automated fluorometric method in the presence and absence of Ca2+ and agents that are known to inhibit access of calcium to enzymes that provide energy. Chlorpromazine (CPZ), an inhibitor of calcium binding to proteins (calcium-dependent enzymes), and ethylene diamine tetra-acetic acid (EDTA), a chelator of Ca2+, increased accumulation and efflux of EtBr at pH 8 but not at pH 5. Ca 2+ reverses these effects when the assay is conducted at pH 8. In conclusion, the activity of the efflux pump system of E. coli is dependent upon metabolic energy at pH 8. Because at pH 8 hydrolysis of ATP is favoured and contributes protons for activation of the AcrAB-TolC efflux pump, CPZ is suspected of having its effects on accumulation/efflux of EtBr by indirectly affecting ATPase activity that is dependent upon Ca2+.

AB - Efflux of antibiotics by Escherichia coli AG100 is performed by a variety of efflux pumps, ensuring survival of the bacterium in widely diverse media. At pH 5, efflux is independent of metabolic energy during the period of time the assay is conducted; at pH 8 it is totally dependent upon metabolic energy. Because calcium ions (Ca2+) are important for membrane transport channels and the activity of ATPases that provide energy functions, the role of Ca2+ in the extrusion of an efflux pump substrate under conditions that challenge the bacterium was investigated. Real-time accumulation and efflux of ethidium bromide (EtBr) by E. coli K-12 AG100 strain [argE3 thi-1 rpsL xyl mtl Δ(gal-uvrB) supE44] was determined by a semi-automated fluorometric method in the presence and absence of Ca2+ and agents that are known to inhibit access of calcium to enzymes that provide energy. Chlorpromazine (CPZ), an inhibitor of calcium binding to proteins (calcium-dependent enzymes), and ethylene diamine tetra-acetic acid (EDTA), a chelator of Ca2+, increased accumulation and efflux of EtBr at pH 8 but not at pH 5. Ca 2+ reverses these effects when the assay is conducted at pH 8. In conclusion, the activity of the efflux pump system of E. coli is dependent upon metabolic energy at pH 8. Because at pH 8 hydrolysis of ATP is favoured and contributes protons for activation of the AcrAB-TolC efflux pump, CPZ is suspected of having its effects on accumulation/efflux of EtBr by indirectly affecting ATPase activity that is dependent upon Ca2+.

KW - Calcium ions

KW - Chlorpromazine

KW - Efflux pumps

KW - Phenothiazine

UR - http://www.scopus.com/inward/record.url?scp=79953855261&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79953855261&partnerID=8YFLogxK

U2 - 10.1016/j.ijantimicag.2011.01.010

DO - 10.1016/j.ijantimicag.2011.01.010

M3 - Article

C2 - 21419607

AN - SCOPUS:79953855261

VL - 37

SP - 410

EP - 414

JO - International Journal of Antimicrobial Agents

JF - International Journal of Antimicrobial Agents

SN - 0924-8579

IS - 5

ER -