Mode of Action of Morganocin 174

Williams, J. A.; Krizsanovich-Williams, Kathryn

doi:10.1128/aac.12.3.395

Cited by 2 publications

(2 citation statements)

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“…120 110 E Ten minutes after the addition of bacteriocin, As with many other bacteriocins, the killing of the Bacteroides cells follows single-hit kinetics, and the interaction of a single molecule of bacteriocin with a target cell occurs in two stages. Pretreatment with 2,4-dinitrophenol inhibits uptake of the bacteriocin, and because it is a known uncoupler of oxidative phosphorylation and dissipator of membrane energy it is suggested that 2,4-dinitrophenol prevents the transmission of the bacteriocin by interfering with the energy supply (14,29). However, a direct interaction of 2,4-dinitrophenol with some membrane component essential for bacteriocin action cannot be ruled out (19).…”

Section: Resultsmentioning

confidence: 99%

Characterization and mode of action of a bacteriocin produced by a Bacteroides fragilis strain

Mossie¹,

Jones²,

Robb³

et al. 1979

Antimicrob Agents Chemother

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A Bacteroides fragilis strain produces a low-molecular-weight (13,500 to 18,700), protemaceous bacteriocin during the stationary growth phase. The extracellular bacteriocin is not inducible by ultraviolet light or mitomycin C and is stable between pH 7.5 and 8.2. The majority of the bacteriocin is thermolabile, but a small proportion (3%) of the bacteriocin is stable after autoclaving at 121°C for 15 min. Killing of sensitive bacteroides cells follows single-hit kinetics, and the interaction of a single molecule of bacteriocin with a target cell occurs in two stages. The killing of susceptible cells is affected by temperature and the growth state of the susceptible cells. The bacteriocin is unusual in that the primary event in its mode of action is the inhibition of RNA synthesis. The bacteriocin inhibits RNA synthesis immediately but has no effect on DNA synthesis or intracellular ATP levels. Protein synthesis is inhibited after a delay of 20 min, presumably as a result of the initial inhibition of RNA synthesis.Since the discovery of bacteriocins by Gratia (10), much work has been done on the bacteriocins produced by aerobic bacteria (11,19,22,23). The colicins produced by Escherichia coli have been particularly well studied, and their modes of action have been identified (11,19,23). However, little work has been carried out on the bacteriocins produced by Bacteroides fragilis, which is the most frequently isolated anaerobe species from clinical specimens (13, 18). Booth et al. (3) investigated bacteriocin production by Bacteroides strains and the role of these strains in the ecology of the colon. Although Booth et al. (3) characterized and partially purified one of the bacteriocins, the mechanism of killing was not determined. We describe the characterization, purification, and unusual mode of action of a B. fragilis bacteriocin. MATERIALS AND METHODSMedia and anaerobic techniques. Brain heart infusion (BHI) broth and agar (17) were used for bacterial growth and bacteriocin production. The glucose minimal medium was similar to that described by Varel and Bryant (28), except that 0.1 M phosphate buffer was used instead of 0.4% Na2CO3. The anaerobic glove box and techniques described by Moodie and Woods (17) (AU) were expressed as the reciprocal of the highest doubling dilution that gave a zone of inhibition surrounding the well.Bacteriocin production. The producer strain was inoculated into BHI broth, and samples of the culture supernatant were assayed for bacteriocin at different time intervals.Induction experiments. Mitomycin C (Calbiochem, La Jolla, Calif.) and ultraviolet irradiation were used to test for induction of the bacteriocin. Exponential-phase cells were added to BHI media containing 0.1, 0.2, 0.3, 0.4, 0.8 and 1.0,g of mitomycin C per ml and incubated for 6 h. Cultures were either assayed for bacteriocin directly or harvested by centrifugation, washed, and suspended in BHI broth for a further 6 h before assaying. Induction by ultraviolet irradiation was carried out on exponential-phase cel...

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Section: Resultsmentioning

confidence: 99%

Characterization and mode of action of a bacteriocin produced by a Bacteroides fragilis strain

Mossie¹,

Jones²,

Robb³

et al. 1979

Antimicrob Agents Chemother

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“…This bacteriocin, morganocin 174, interferes with the energy metabolism of sensitive cells. Characteristics of this interference include inhibition of macromolecular synthesis and intracellular accumulation of glutamine and proline, efflux of K+, and rapid depletion of intracellular ATP (12). Although the genetic determinant of morganocin 174, plasmid Morl74, is nonconjugative, conjugal transfer may be mediated by a mobilizing plasmid, kanamycin re-"cleared" lysate was centrifuged to equilibrium in cesium chloride (CsCl)-ethidium bromide (EtBr).…”

mentioning

confidence: 99%

Physical properties of plasmid Mor174, which determines bacteriocin production in Proteus morganii 174

Williams¹,

Krizsanovich-Williams²

1978

J Bacteriol

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Plasmid Morl74 has a molecular weight of 3.6 x 106 and a buoyant density of 1.6994 g/cm3. The covalently closed circular form has a sedimentation coefficient of 22S. There are 30 to 40 plasmid copies per genome equivalent, but growth in chloramphenicol results in amplification of the copy number to 600. In Proteus morganii 174, Morl74 coexists with a cryptic plasmid of molecular weight 15.8 x 10' and a buoyant density of 1.7170 g/cm3.

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Mode of Action of Morganocin 174

Cited by 2 publications

References 25 publications

Characterization and mode of action of a bacteriocin produced by a Bacteroides fragilis strain

Characterization and mode of action of a bacteriocin produced by a Bacteroides fragilis strain

Physical properties of plasmid Mor174, which determines bacteriocin production in Proteus morganii 174

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