Potassium fluxes, first indications of membrane damage in micro-organisms

Lambert, Peter A.; Hammond, Stephen M.

doi:10.1016/0006-291x(73)91494-0

Cited by 144 publications

(103 citation statements)

References 3 publications

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“…Evidence of butyricin's action on the cell membrane of C. pasteurianum was provided by the butyricin-provoked efflux of ssRb+. Flux of ssRb+ has been much used as an indicator of the fate of K+ ions in bacteria since transport of K+ and Rb+ is generally competitive (Wendt, 1970); and leakage of intracellular K+ has been regarded as one of the first signs of membrane damage (Lambert & Hammond, 1973). In this respect, butyricin 7423 resembles several other bacteriocins that act at the cell membrane and cause rapid efflux of 86Rb+, e.g.…”

Section: Discussionmentioning

confidence: 99%

Butyricin 7423: a Bacteriocin Produced by Clostridium butyricum NCIB7423

Clarke¹,

Morris²

1976

Journal of General Microbiology

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SUMMARYButyricin 7423 is a trypsin-sensitive bacteriocin produced by Clostridium butyricum ~~1~7 4 2 3 and active against some other species of Clostridium. It has a bactericidal but non-lytic action on growing cultures of Clostridium pasteurianum. The primary action of butyricin 7423 appears to be at the cell membrane. Thus treatment of C. pasteurianum with an excess of butyricin altered the permeability of its cell membrane, allowing the release of several metabolites and ions. Efflux of rubidium ions from organisms preloaded with 8sRb+ was particularly rapid and extensive. The action of butyricin 7423 on Clostridium species seems to differ from that of other clostridocins, such as the boticins and perfringocin 28, and more closely resembles the mode of action on susceptible (aerobic) organisms of bacteriocins such as staphylococcin 1580 or colicins A, EI, I and K.

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Section: Discussionmentioning

confidence: 99%

Butyricin 7423: a Bacteriocin Produced by Clostridium butyricum NCIB7423

Clarke¹,

Morris²

1976

Journal of General Microbiology

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“…· ISE have been used to assay free K+ in biological samples. Most of the work has been carried out using valinomycin-based solid-state and liquid-membrane electrodes (Walker, 1971;Lambert and Hammond, 1973;Smith eta/., 1973;Cattrall et al, 1974;Haemmerli et al, 1980). These electrodes have the following main characteristics (Bailey, 1976;Covington and Davison, 1979;Cattrall, 1979;Moody and Thomas, 1979;Ma and Hassan, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…Biological work is usually carried out at neutral pH, and although K+ -selective glass electrodes have been used for many years in biological research (Hinke, 1959(Hinke, , 1961Khuri el al., 1963;Portnoy et al, 1963;Lev, 1964;Jacobson, 1966;Lambert and Hammond, 1973;Gale, 1974;Kroll and Anagnostopoulos, 1981;Borst-Pauwels and Theuvenet, 1985;Theuvenet et al, 1987), there is no detailed study of its performance in neutral 1 -100 mM TRIS-HCl pH 7.20; 3-100 mM imidazole--HCl pH 6.50; 5-10 mM TRIS-DMGA pH 7.00; 7 -10 mM Ca 2 + -PIPES pH 6.50; 2 -20 mM imidazole-HCl pH 6.50 4 -1 mM Mg 2 + -PIPES pH 6.50 6 -100 mM ethanolamine-DMGA pH 6.50 8 -10 mM Ml+ -PIPES pH 6.50 9 -10 mM Na + -DMGA pH 6.50; 10 -10 mM Na +-PIPES pH 6.50…”

Section: Introductionmentioning

confidence: 99%

The assay of free potassium in biological buffers with a K⁺-selective glass electrode

Cabral

1992

Chemical Speciation & Bioavailability

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The performance of the Kent K+ -selective glass electrode in several biological buffers at neutral pH was evaluated in terms of Nernstian response, repeatability, response time and selectivity. The electrode exhibited a linear response between 2 x 10-5 to 5 x 10-4 and 10-2 M K+, with a slope of 54.9-63.1 mV per decade change in K+ activity. In successive calibrations in the range of 10--s to 10-2 M K+, the coefficient of variation of the potential in a given K+ concentration decreased with increasing K+ concentration, and was lower than 5%, indicating that in this range of concentrations, the electrode exhibited good repeatability. The response time for a sudden tenfold increase in K+ concentration was 1.3-3.6 min for 10-5 M, and 0.5-1 min for 10-4M K+. The influence of Ca 2 + and Mg 2 + on electrode. potential was very small, but Na+ and H+ strongly interfered with electrode response. The selectivity coefficient K+/Na+ was 0.11 and K+;H+ 3.8. The results suggested that in several biological buffers containing no Na+ and with neutral pH, the K+ -selective glass electrode can be used to assay with accuracy and rapidity free potassium in the range of 10-5 to 10-2 M, being therefore an alternative to valinomycin-based electrodes.

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“…Qin Xiang, Ng 1 * 11 12 1 National University of Singapore, Yong Loo Lin School of Medicine, 13 Singapore 117597 14 …”

mentioning

confidence: 99%

“…effective at the lowest concentration tested; so as to enable a lower concentration/ dosage 173 antibiotic [14], and (iii) inhibition of efflux pumps thus allowing accumulation of the antibiotic 221 within the bacterial cell [15]. …”

mentioning

confidence: 99%

To investigate the antimicrobial effects of extracted polyphenols from green tea (Camellia sinensis) and banana (Musa sp.) leaves

2015

Preprint

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In recent years, there is an emergence of antibiotic-resistant bacterial strains due to the indiscriminate use of antibiotics, commonly prescribed to treat infectious diseases. The increasing occurrence of antibiotic resistance has undoubtedly made bacterial infections a greater health risk and threat than before. In this project, the use of natural polyphenolic compounds, extracted from green tea (Camellia sinensis) and banana (Musa sp.) leaves, as a novel antimicrobial chemotherapeutic agent was investigated. This study examined their bactericidal effects on Escherichia coli and Micrococcus luteus, and also evaluated the potential synergistic ability of these polyphenol-rich extracts when used alongside the beta-lactam antibiotic ampicillin. For the same dry mass of plant material used (3g), the prepared green tea extract had a higher total polyphenol concentration than that of banana leaves extract (495.1mg/L as compared to 221.6mg/L respectively). Subsequently, bacterial broth of 10 5 colony forming units/ml was mixed with varying concentrations of the different test compounds before plating 10µl of the mixture and quantifying the compounds' bactericidal effect by doing a viable count after overnight incubation. The green tea extract showed the greatest bactericidal effect on E. coli and M. luteus as compared to the banana leaves extract and ampicillin. Against E. coli, this difference was confirmed to be significant (p<0.05) using one-way ANOVA and Tukey's post-hoc analysis.

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Potassium fluxes, first indications of membrane damage in micro-organisms

Cited by 144 publications

References 3 publications

Butyricin 7423: a Bacteriocin Produced by Clostridium butyricum NCIB7423

Butyricin 7423: a Bacteriocin Produced by Clostridium butyricum NCIB7423

The assay of free potassium in biological buffers with a K⁺-selective glass electrode

To investigate the antimicrobial effects of extracted polyphenols from green tea (Camellia sinensis) and banana (Musa sp.) leaves

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Potassium fluxes, first indications of membrane damage in micro-organisms

Cited by 144 publications

References 3 publications

Butyricin 7423: a Bacteriocin Produced by Clostridium butyricum NCIB7423

Butyricin 7423: a Bacteriocin Produced by Clostridium butyricum NCIB7423

The assay of free potassium in biological buffers with a K+-selective glass electrode

To investigate the antimicrobial effects of extracted polyphenols from green tea (Camellia sinensis) and banana (Musa sp.) leaves

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The assay of free potassium in biological buffers with a K⁺-selective glass electrode