The Electrophoretic Mobility of Micro-Organisms

Richmond, D. V.; Fisher, David J.

doi:10.1016/s0065-2911(08)60375-6

Cited by 56 publications

(26 citation statements)

References 90 publications

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“…The EPM of human red blood cells was also measured to verify the apparatus. The EPM of human erythrocytes, -1 .31 x 10 -8m2 V -1 s -1 at both lower and upper stationary levels, in 0.067 M phosphate buffer (pH 7.4) at 25°C agreed with previously reported values (9,12).…”

Section: Methodssupporting

confidence: 90%

The cell surface charge of fast- and slow-growing bacteria isolated from grassland soil.

Morisaki

Kasahara

Hattori

1993

J. Gen. Appl. Microbiol.

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Section: Methodssupporting

confidence: 90%

The cell surface charge of fast- and slow-growing bacteria isolated from grassland soil.

Morisaki

Kasahara

Hattori

1993

J. Gen. Appl. Microbiol.

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“…Zeta potential is an indicator of the surface charge (Richmond & Fisher, 1973). Since melanin is a negatively charged polymer, measurement of zeta potential is one way to determine whether various substrates are equally incorporated into melanin.…”

Section: Methodsmentioning

confidence: 99%

Cryptococcus neoformans laccase catalyses melanin synthesis from both d- and l-DOPA

et al. 2007

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The human fungal pathogen Cryptococcus neoformans produces melanin in the presence of various substrates, including the L enantiomer of 3,4-dihydroxyphenylalanine (DOPA). The enzyme laccase catalyses the formation of melanin by oxidizing L-DOPA, initiating a series of presumably spontaneous reactions that ultimately leads to the polymerization of the pigment in the yeast cell wall. There, melanin protects the cell from a multitude of environmental and host assaults. Thus, the ability of C. neoformans to produce pigments from a variety of available substrates is likely to confer a survival advantage. A number of C. neoformans isolates of different serotypes produced pigments from D-DOPA, the stereoisomer of L-DOPA. Acid-resistant particles were isolated from pigmented C. neoformans cells grown in the presence of D-DOPA. Biophysical characterization showed the particles had a stably detectable free-radical signal by EPR, and negative zeta potential, similar to L-DOPA-derived particles. No major differences were found between L-and D-DOPA ghosts in terms of binding to anti-melanin antibodies, or in overall architecture when imaged by electron microscopy. C. neoformans cells utilized L-and D-DOPA at a similar rate. Overall, our results indicate that C. neoformans shows little stereoselectivity for utilizing DOPA in melanin synthesis. The ability of C. neoformans to use both L and D enantiomers for melanization implies that this organism has access to a greater potential pool of substrates for melanin synthesis, and this could potentially be exploited in the design of therapeutic inhibitors of laccase.

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“…However, freshly harvested spores of G. candidurn had a peak of negative spore mobility (i.e. they moved towards the anode) between pH 3 and pH 4 and the pH-mobility curve of this species was unlike the pHmobility curves of all other fungal spores so far studied in showing such a sharp peak (Douglas et al, 1959;Fisher, 1973;Richmond & Fisher, 1971). However, the pH-mobility curve of G. candidurn resembled that of a methicillin-sensitive strain of Staphylococcus aureus (Hill & James, 1972).…”

Section: E T H O D Smentioning

confidence: 99%

Effects of Junlon and Hostacerin on the Electrokinetic Properties of Spores of Aspergillus niger, Phanerochaete chrysosporium and Geotrichum candidum

1988

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The electrophoretic behaviour of freshly harvested spores of Aspergillus niger, Phanerochaete chrysosporium and Geotrichum candidum was determined in solution at various pH values. Freshly harvested spores of all three species lacked positive mobility at low pH values, suggesting a preponderance of acidic surface groups. Spores of the 'non-aggregating' fungus, G. candidum, had a pH-mobility curve (peak of negative mobility between pH 3 and 4) which was quite different to those of spores of the 'aggregating' fungi, A . niger and P. chrysosporium. The pH-mobility curve of swollen spores of A . niger which had been incubated in medium differed from that of freshly harvested spores, suggesting that changes in the wall that occur during germination alter the electrophoretic properties of the spores; swollen spores of A . niger, unlike freshly harvested spores, had a negative mobility maximum at pH 5.0.After treatment with Junlon-110 (a polyacrylic acid), spores of all three species had similar pH-mobility curves and all had peaks of negative mobility at pH 4.0. The electrophoretic mobility of spores of P. chrysosporium at pH 6.5 increased linearly with the concentration (0.01-0.4%, w/v) of Junlon used in the pre-treatment ; electrophoretic mobility after pre-treatment with 0.005-0.1 % (w/v) Hostacerin (sodium polyacrylate) increased only up to 0.01 % (w/v) Hostacerin. The results obtained show that Junlon-1 10 and Hostacerin bind to fungal walls, and it is possible that spore and hyphal aggregation is reduced by these compounds because of repulsion between particles resulting from ionized carboxyl groups on the polymer.

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The Electrophoretic Mobility of Micro-Organisms

Cited by 56 publications

References 90 publications

The cell surface charge of fast- and slow-growing bacteria isolated from grassland soil.

The cell surface charge of fast- and slow-growing bacteria isolated from grassland soil.

Cryptococcus neoformans laccase catalyses melanin synthesis from both d- and l-DOPA

Effects of Junlon and Hostacerin on the Electrokinetic Properties of Spores of Aspergillus niger, Phanerochaete chrysosporium and Geotrichum candidum

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