A comparison of five methods for assaying bacterial hydrophobicity

Dillon, Jasmine; Fuerst, John A.; Hayward, A. C.; Davis, G. H. G.

doi:10.1016/0167-7012(86)90027-8

Cited by 96 publications

(46 citation statements)

References 18 publications

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“…This was not confirmed by the MATH data. The lack of agreement between water contact angles and MATH data has also been reported by others (29)(30)(31). Strains with a high ARR value, had a low MATH value whereas strains with a low ARR value had a relatively high MATH value, except for strain O8K(A)28.…”

Section: Cell Biophysicssupporting

confidence: 67%

Physicochemical characterization ofEscherichia coli

et al. 1992

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Eight Escherichia coli strains were characterized by determining their adhesion to xylene, surface free energy, zeta potential, relative surface charge, and their chemical composition. The latter was done by applying X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy OR). No relationship between the adhesion to xylene and the water contact angles of these strains was found. Three strains had significantly lower surface free energies than the other strains. Surface free energies were either obtained from polar and dispersion parts or from Lifshitz-van der Waals and acid/base parts of the surface free energy. A correlation (r = 0.97) between the polar parts and the electron-donor contributions to the acid/base part of the surface free energy was found. The zeta potentials of all strains, measured as a function of pH *Author to whom all correspondence and reprint requests should be addressed. Cell Biophysics 1 7Volume 20, 1992 18Harkes et al.(2-11), were negative. Depending on the zeta potential as a function of pH, three groups were recognized among the strains tested. A relationship (r = 0.84) was found between the acid/base component of the surface free energy and the zeta potential measured at pH = 7.4. There was no correlation between results of XPS and IR studies. Data from the literature of XPS and IR studies of the gram-positive staphylococci and streptococci were compared with data from the gram-negative E. coli used in this study. It appeared that in these three groups of bacteria, the polysaccharide content detected by IR corresponded well with the oxygen-to-carbon ratio detected by XPS.

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Section: Cell Biophysicssupporting

confidence: 67%

Physicochemical characterization ofEscherichia coli

et al. 1992

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“…Although both procedures are most commonly employed to assess microbial CSH and both are thought to measure actual binding to hydrophobic ligands (52), a lack of correlation has been reported by other workers (9, 10, 13, 39, 52). Dillon et al (9) and Van der Mei et al (52) found better correspondence between the tests when they were applied to closely related strains, which suggests that the assays may measure essentially different cell properties. Hence, general conclusions regarding the impact of CSH on biotic interactions should be drawn very carefully.…”

Section: Discussionmentioning

confidence: 98%

Effects of Hydrophobic and Electrostatic Cell Surface Properties of Bacteria on Feeding Rates of Heterotrophic Nanoflagellates

Matz

Jürgens

2001

Appl Environ Microbiol

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The influence of cell surface hydrophobicity and electrostatic charge of bacteria on grazing rates of three common species of interception-feeding nanoflagellates was examined. The hydrophobicity of bacteria isolated from freshwater plankton was assessed by using two different methods (bacterial adhesion to hydrocarbon and hydrophobic interaction chromatography). The electrostatic charge of the cell surface (measured as zeta potential) was analyzed by microelectrophoresis. Bacterial ingestion rates were determined by enumerating bacteria in food vacuoles by immunofluorescence labelling via strain-specific antibodies. Feeding rates varied about twofold for each flagellate species but showed no significant dependence on prey hydrophobicity or surface charge. Further evidence was provided by an experiment involving flagellate grazing on complex bacterial communities in a two-stage continuous culture system. The hydrophobicity values of bacteria that survived protozoan grazing were variable, but the bacteria did not tend to become more hydrophilic. We concluded that variability in bacterial cell hydrophobicity and variability in surface charge do not severely affect uptake rates of suspended bacteria or food selection by interception-feeding flagellates.Grazing by phagotrophic protists can be considered a major source of mortality for suspended bacteria in marine and freshwater systems. In particular, heterotrophic nanoflagellates, which feed mostly by direct interception of single bacterial cells, have been identified as the main consumers of planktonic bacteria (12,40,46). There is increasing interest in qualitative aspects of this important selective agent for bacterial communities, such as selective grazing and adaptation of bacteria to predation. Recent studies have revealed that grazing is an important force shaping the structure and composition of communities of planktonic bacteria (17,20,28,51). Bacterial cell size is one of the major phenotypic traits which influence the predator-prey relationship between bacteria and heterotrophic nanoflagellates. Grazing rates increase with bacterial size (15, 48) due to increased encounter rates (11). On the other hand, bacteria reach a predation refuge when they grow beyond a certain size as they become morphologically inedible for nanoflagellates (21,22). In field and laboratory studies it has been shown that size-related differences in predation vulnerability can result in shifts in bacterial species composition during enhanced protozoan grazing (28, 49).It has been speculated that properties of bacteria other than size might also be relevant for vulnerability to grazers (27). There is, however, little evidence of effects of other phenotypic traits, such as motility (14) or the chemical surface composition (26,31,35,45) of bacterial cells, on protist grazing rates. Studies of bacterial ingestion (phagocytosis) by phagocytes of mammalian immune systems have revealed that bacterial surface properties, especially hydrophobicity, strongly affect the contact probability an...

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“…However, a common concern is that it is difficult to directly compare results obtained from different laboratories using different or even similar tests (8). Surfaces of spores are heterogenous and contain a combination of functional groups such as carboxylate, amine, and phosphate groups, which may account for some of the variation between the different tests.…”

Section: Discussionmentioning

confidence: 99%

Recovery of Spores from Thermophilic Dairy Bacilli and Effects of Their Surface Characteristics on Attachment to Different Surfaces

Seale

Flint

McQuillan

et al. 2008

Appl Environ Microbiol

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Spores from four Geobacillus spp. were isolated from a milk powder manufacturing line in New Zealand. Liquid sporulation media produced spore yields of ϳ10 7 spores ml ؊1 ; spores were purified using a two-phase system created with polyethylene glycol 4000 and 3 M phosphate buffer. The zeta potentials of the spores from the four isolates ranged from ؊10 to ؊20 mV at neutral pH, with an isoelectric point between pH 3 and 4. Through contact angle measurements, spores were found to be hydrophilic and had relative hydrophobicity values of 10 to 40%, as measured by the microbial adhesion to hexadecane assay. The most hydrophilic spore isolate with the smallest negative charge attached in the highest numbers to Thermanox and stainless steel (1 ؋ 10 4 spores cm ؊2 ), with fewer spores attaching to glass (3 ؋ 10 3 spores cm ؊2 ). However, spores produced by the other three strains attached in similar numbers (P > 0.05) to all substrata (ϳ1 ؋ 10 3 spores cm ؊2), indicating that there was no simple relationship between individual physicochemical interactions and spore adherence. Therefore, surface modifications which limit the attachment of one strain may not be effective for all stains, and control regimens need to be devised with reference to the characteristics of the particular strains of concern.The presence of spores of thermophilic bacilli are a common problem during milk powder manufacture (32). Thermophilic spores from bacteria such as Geobacillus spp. are normally present in low numbers in the raw milk (31). However, high numbers are often found in the milk powder. The source of these spores is believed to be thermophilic bacteria growing on the surfaces within the heat exchangers and evaporators (43). Biofilms are formed when spores present in the raw milk survive pasteurization, adhere to stainless steel surfaces, and germinate when and where conditions are suitable. As the biofilm matures, cells and spores can slough off and contaminate the product flowing past (13). Spore concentrations as high as 10 5 spores g Ϫ1 can occur in milk powder, resulting in it being downgraded to a lower-value product. As established biofilms are difficult to eradicate (20), prevention of the initial attachment is an alternative approach to control biofilm formation. The initial attachment of microorganisms, including spores, to surfaces is due to physicochemical interactions between their surfaces and the substratum, which are described by the extended Derjaguin, Landau, Verwey, and Overbeek theory (53). Such forces include Lifshitz-van der Waal's, acid/base, and electrostatic interactions. An improved understanding of the interactions that impact spore attachment may help in the development of strategies to reduce spore adherence.Several studies have used electron microscopy and atomic force microscopy to examine the physical structure of the spore's surface (7,18,28). However there have been few studies of the surface chemistry of spores, and it is likely that what little information is known may not be broadly applicable acro...

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A comparison of five methods for assaying bacterial hydrophobicity

Cited by 96 publications

References 18 publications

Physicochemical characterization ofEscherichia coli

Physicochemical characterization ofEscherichia coli

Effects of Hydrophobic and Electrostatic Cell Surface Properties of Bacteria on Feeding Rates of Heterotrophic Nanoflagellates

Recovery of Spores from Thermophilic Dairy Bacilli and Effects of Their Surface Characteristics on Attachment to Different Surfaces

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