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  • 1
    Electronic Resource
    Electronic Resource
    Physico-chemical surface characteristics and adhesive properties of Streptococcus salivarius strains with defined cell surface structures (1987)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 40 (1987), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Physico-chemical surface characteristics and adhesive properties of a series of mutants of Streptococcus salivarius HB with defined cell surface structures were determined. Zeta potentials showed no relation either with the presence or absence of specific antigens on the bacterial cell surface, or with the adhesive properties of the cells. Hydrophobicity was assessed by surface free energy determination from measured contact angles, by adsorption to hexadecane and by hydrophobic interaction chromatography. Generally, the progressive removal of fibril subclasses from the cell surface resulted in a reduced hydrophobicity. However, specific fibrillar subclasses appeared to contribute to surface hydrophobicity to widely different extents. Bacterial adhesion to polymethylmethacrylate increased with increasing hydrophobicity of the mutants. However, adhesion to a more complex biological substratum, such as saliva-coated hydroxyapatite, correlated only partly with hydrophobicity. The organism, deprived of most of its fibrillar surface structures, clearly showed the least adhesion to hydrophobic ligands, to both polymethylmethacrylate and saliva-coated hydroxyapatite, and had a significantly higher surface free energy than the other mutants and the parent strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1987.tb01974.x
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  • 2
    Electronic Resource
    Electronic Resource
    Reversibility of adhesion of oral streptococci to solids (1986)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 35 (1986), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The reversibility of adhesion of 3 representative strains of oral streptococci from a phosphate-buffered suspension onto 5 different solid substrata was studied. Streptococcus mitis T9 (surface free energy γb= 39 mJ · m−2). Streptococcus sanguis CH3 (γb= 95 mJ · m−2) and Streptococcus mutans NS (γb= 117 mJ · m−2) were selected on basis of their surface free energy. Solid substrata were employed with a surface free energy γs ranging from 20 mJ · m−2 for polytetrafluorethylene to 109 mJ · m−2 for glass. Bacterial suspensions containing 2.5 × 109 cells per ml were incubated with 2 samples of each substratum. After 1 h the number of adhering bacteria was evaluated on one sample, while the second sample was kept for another hour at a 10-fold lower bacterial concentration. Bacteria with a low surface free energy desorbed only from substrata with a high surface free energy, while bacteria with a high surface free energy desorbed from substrata with a low surface free energy. Thus low energy bacterial strains adhered reversibly to high energy substrata and vice versa. Similar observations were made with polystyrene particles. Calculation of the interfacial free energy of adhesion (ΔFadh) for each bacterial strain as well as for the polystyrene particles showed that a reversible adhesion was associated with a positive ΔFadh, denoting unfavourable adhesion conditions upon a thermodynamic basis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1986.tb01547.x
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  • 3
    Electronic Resource
    Electronic Resource
    Surface free energies of oral streptococci (1984)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 25 (1984), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The surface free energies (γb) of a variety of oral streptococci were determined from contact angle measurements on bacterial deposits, using the concept of dispersion and polar components. At least four strains of each species were tested. Strains of Streptococcus mutans, S. sanguis and S. salivarius possessed relatively high surface free energies (103 ± 12 mJ · m−2) and at the species level no significant difference was found. In contrast, the strains of S. mitis had remarkably low surface free energies (45 ± 14 mJ · m−2). S. milleri appeared to be a heterogeneous species, showing surface free energies over a range of 32–119 mJ · m−2. No significant differences were observed between laboratory strains and strains freshly isolated from the oral cavity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1984.tb01472.x
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  • 4
    Electronic Resource
    Electronic Resource
    Specific and non-specific interactions in bacterial adhesion to solid substrata (1987)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 46 (1987), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Based on a literature review, a hypothesis is forwarded on the mechanism of initial bacterial adhesion to solid substrata, which accounts both for the role of specific microscopic surface components as well as for the role of non-specific macroscopic surface properties (surface free energy, zeta potential or hydrophobicity). Three distinct regions in the adhesion process are suggested in which at large and intermediate separation distances adhesion is mediated by the macroscopic surface properties as surface free energy and surface charge, respectively. At small separation distances specific short-range interactions can occur, leading to a strong and irreversible bonding, provided the water film present in between the interaction surfaces can be removed. A major role of hydrophobic groups, supposed to be associated with bacterial surface appendages is suggested to be its dehydrating capacity, enabling the removal of the vicinal water film yielding small areas of direct contact between protruberant parts of the cell surface and the substratum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1987.tb02457.x
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  • 5
    Electronic Resource
    Electronic Resource
    The growth rate regulates the composition and density of the fibrillar coat on the surface of Streptococcus salivarius K+ cells (1986)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 33 (1986), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Streptococcus salivarius HB (Lancefield group K) was grown in continuous culture on a chemically defined medium under glucose limitation. The structure and composition of the cell surface was investigated using negative-stain electron microscopy of whole cells and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and rocket immunoelectrophoresis (RIEP) of mutanolysin-solubilized cell-wall fractions. Under most steady-state growth conditions the density of the fibrillar fringe varied from cell to cell, whereas most stationary-phase batch-grown cells exhibited a uniformly dense fibrillar fringe. Varying the generation time at pH 7 over the range from 44 to 560 min profoundly affected both the density of the fibrillar layer and the distribution of specific protein antigens. At intermediate growth rates the fibrillar adhesins AgB and AgC were optimally expressed. At high growth rates the cells were virtually bald and the adhesins were absent from the cell walls. AgD and an unidentified cell wall-associated protein, however, were expressed at all growth rates tested. Slowly growing cells apparently lacked protease-resistant long fibrils but possessed the proteinaceous adhesins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1986.tb01267.x
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  • 6
    Electronic Resource
    Electronic Resource
    Surface free energies of oral streptococci and their adhesion to solids (1985)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 30 (1985), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The adhesion of 3 strains of oral streptococci from a buffered suspension onto 3 different solid substrata was studied. Representative strains of streptococci were selected on the basis of their surface free energy (γb), namely Streptococcus mitis L1 (γb= 37 mJ·m−2), Streptococcus sanguis CH3 (95 mJ·m−2) and Streptococcus mutans NS (117 mJ·m−2). Solid substrata were also selected on basis of their surface free energy (γs), and included polytetrafluorethylene (γs= 20 mJ·m−2), polymethylmethacrylate (53 mJ·m−2) and glass (109 mJ·m−2). Bacterial adhesion was measured as the number of bacteria adhering per cm2 at equilibrium. Equilibrium was usually obtained within 20 min. S. sanguis CH3, having an intermediate surface free energy did not show a clear preference for any of the 3 solids. S. mitis L1, however, the lowest surface free energy strain, adhered in highest numbers to the low energy solid PTFE, whereas the highest γb strain, S. mutans NS, adhered in highest numbers to the highest γs solid, glass. Calculation of the interfacial free energy of adhesion (ΔFadh) for each bacterial strain showed that this parameter was predictive of bacterial adhesion to solid substrata.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1985.tb00993.x
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  • 7
    Electronic Resource
    Electronic Resource
    Adhesive cell wall-associated glycoprotein of Streptococcus salivarius (K+) is a cell surface fibril (1984)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 23 (1984), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The structure of a cell wall-associated glycoprotein, supposed to be involved in host-related adherence of Streptococcus salivarius (K+) strains, was investigated. The Mr of the two major subclasses of the glycoprotein was estimated to be in the range of 230 000 to 295 000, both in the presence of SDS and under non-denaturating conditions. Circular dichroism spectra indicated an α-helix content of 45%. Electron microscopic observation of rotary shadowed individual molecules showed fibrillar structures with an average length of 870 ± 40 Å and a width of 75 ± 6 Å. The glycoprotein is presumably identical with a class of long fibrils found on the surface of these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1984.tb01054.x
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  • 8
    Electronic Resource
    Electronic Resource
    On a relation between interfacial free energy-dependent and noninterfacial free energy-dependent adherence of oral streptococci to solid substrata (1988)
    Springer
    Current microbiology 16 (1988), S. 311-313 
    Details
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In several systems bacterial adhesion occurs despite a positive interfacial free energy of adhesion, ΔFadh; this implies that other interactions are involved. We hypothesize that the number of bacteria adhering at ΔFadh=0 represents their ability to adhere by other, i.e., non-ΔFadh-dependent interactions. Eight strains of oral streptococci were allowed to adhere to three solid substrata with different surface free energies in a flow cell system. Strain-specific linear relations were found between the numbers of bacteria adhering at saturation, nb,s, and ΔFadh. When for all strains the numbers of adhering bacteria at ΔFadh=0 were plotted versus the slopes, denoting the sensitivity to ΔFadh, a linear relationship (r=0.92) was observed. It is, therefore, concluded that one strain-specific factor influences both ΔFadh-dependent and non-ΔFadh-dependent adherence. The numerical value of this factor, together with a surface energetic analysis, predicts the number of streptococci that will adhere to a given nonbiological substratum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01568537
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  • 9
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    Biosafety Assessment of the Application of Genetically Modified Lactococcus lactis spp. in the Production of Fermented Milk Products (1995)
    Elsevier
    Details
    Publication Date: 1995-01-01
    Print ISSN: 0723-2020
    Electronic ISSN: 1618-0984
    Topics: Biology
    Published by Elsevier
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  • 10
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    On a relation between interfacial free energy-dependent and noninterfacial free energy-dependent adherence of oral streptococci to solid substrata (1988)
    Springer
    Details
    Publication Date: 1988-11-01
    Print ISSN: 0343-8651
    Electronic ISSN: 1432-0991
    Topics: Biology , Medicine
    Published by Springer
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