Plasmid encoded antibiotics inhibit protozoan predation of Escherichia coli K12

Adnan Ahmetagic, Daniel Philip, Derek Sarovich, Daniel Kluver, John Pemberton

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Bacterial plasmids and phages encode the synthesis of toxic molecules that inhibit protozoan predation. One such toxic molecule is violacein, a purple pigmented, anti-tumour antibiotic produced by the Gram-negative soil bacterium Chromobacterium violaceum. In the current experiments a range of Escherichia coli K12 strains were genetically engineered to produce violacein and a number of its coloured, biosynthetic intermediates. A bactivorous predatory protozoan isolate, Colpoda sp.A4, was isolated from soil and tested for its ability to ‘graze’ on various violacein producing strains of E. coli K12. A grazing assay was developed based on protozoan “plaque” formation. Using this assay, E. coli K12 strains producing violacein were highly resistant to protozoan predation. However E. coli K12 strains producing violacein intermediates, showed low or no resistance to predation. In separate experiments, when either erythromycin or pentachlorophenol were added to the plaque assay medium, protozoan predation of E. coli K12 was markedly reduced. The inhibitory effects of these two molecules were removed if E. coli K12 strains were genetically engineered to inactivate the toxic molecules. In the case of erythromycin, the E. coli K12 assay strain was engineered to produce an erythromycin inactivating esterase, PlpA. For pentachlorophenol, the E. coli K12 assay strain was engineered to produce a PCP inactivating enzyme pentachlorophenol-4-monooxygenase (PcpB). This study indicates that in environments containing large numbers of protozoa, bacteria which use efflux pumps to remove toxins unchanged from the cell may have an evolutionary advantage over bacteria which enzymatically inactivate toxins.
Original languageEnglish
Pages (from-to)152-158
Number of pages7
JournalPlasmid
Volume66
Issue number3
DOIs
Publication statusPublished - 2011

Fingerprint

Escherichia coli K12
Plasmids
Anti-Bacterial Agents
Poisons
Pentachlorophenol
Soil
Chromobacterium
Bacteria
Erythromycin
Gram-Negative Bacteria
Bacteriophages
violacein
Enzymes

Cite this

Ahmetagic, A., Philip, D., Sarovich, D., Kluver, D., & Pemberton, J. (2011). Plasmid encoded antibiotics inhibit protozoan predation of Escherichia coli K12. Plasmid, 66(3), 152-158. https://doi.org/10.1016/j.plasmid.2011.07.006
Ahmetagic, Adnan ; Philip, Daniel ; Sarovich, Derek ; Kluver, Daniel ; Pemberton, John. / Plasmid encoded antibiotics inhibit protozoan predation of Escherichia coli K12. In: Plasmid. 2011 ; Vol. 66, No. 3. pp. 152-158.
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Ahmetagic, A, Philip, D, Sarovich, D, Kluver, D & Pemberton, J 2011, 'Plasmid encoded antibiotics inhibit protozoan predation of Escherichia coli K12', Plasmid, vol. 66, no. 3, pp. 152-158. https://doi.org/10.1016/j.plasmid.2011.07.006

Plasmid encoded antibiotics inhibit protozoan predation of Escherichia coli K12. / Ahmetagic, Adnan; Philip, Daniel; Sarovich, Derek; Kluver, Daniel; Pemberton, John.

In: Plasmid, Vol. 66, No. 3, 2011, p. 152-158.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Ahmetagic, Adnan

AU - Philip, Daniel

AU - Sarovich, Derek

AU - Kluver, Daniel

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AB - Bacterial plasmids and phages encode the synthesis of toxic molecules that inhibit protozoan predation. One such toxic molecule is violacein, a purple pigmented, anti-tumour antibiotic produced by the Gram-negative soil bacterium Chromobacterium violaceum. In the current experiments a range of Escherichia coli K12 strains were genetically engineered to produce violacein and a number of its coloured, biosynthetic intermediates. A bactivorous predatory protozoan isolate, Colpoda sp.A4, was isolated from soil and tested for its ability to ‘graze’ on various violacein producing strains of E. coli K12. A grazing assay was developed based on protozoan “plaque” formation. Using this assay, E. coli K12 strains producing violacein were highly resistant to protozoan predation. However E. coli K12 strains producing violacein intermediates, showed low or no resistance to predation. In separate experiments, when either erythromycin or pentachlorophenol were added to the plaque assay medium, protozoan predation of E. coli K12 was markedly reduced. The inhibitory effects of these two molecules were removed if E. coli K12 strains were genetically engineered to inactivate the toxic molecules. In the case of erythromycin, the E. coli K12 assay strain was engineered to produce an erythromycin inactivating esterase, PlpA. For pentachlorophenol, the E. coli K12 assay strain was engineered to produce a PCP inactivating enzyme pentachlorophenol-4-monooxygenase (PcpB). This study indicates that in environments containing large numbers of protozoa, bacteria which use efflux pumps to remove toxins unchanged from the cell may have an evolutionary advantage over bacteria which enzymatically inactivate toxins.

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DO - 10.1016/j.plasmid.2011.07.006

M3 - Article

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EP - 158

JO - Plasmid

JF - Plasmid

SN - 0147-619X

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