| 1. |
- Miörner, Håkan, et al.
(författare)
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Effect of specific binding of human albumin, fibrinogen, and immunoglobulin G on surface characteristics of bacterial strains as revealed by partition experiments in polymer phase systems
- 1980
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Ingår i: Infection and Immunity. - 1098-5522. ; 29:3, s. 879-885
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Tidskriftsartikel (refereegranskat)abstract
- Four strains of gram-positive cocci with different combinations of positive binding of human proteins were investigated with respect to changes in physicochemical surface properties after specific protein binding. Staphylococcus aureus Cowan I, two group A beta-hemolytic streptococci, and one group G streptococcal strain were studied; they represented three different combinations of reactivity for human serum albumin, human immunoglobulin G, and fibrinogen. Using single-tube partition of bacterial cells in a dextran-polyethylene glycol system of constant polymer concentration but varying ionic compositions, it was possible to detect changes in the partition of bacteria after specific protein binding. There was a correlation between the binding of radiolabled human proteins to the bacterial strains and the effect of human proteins on the partition of the bacteria in the phase systems. Thus, the specific binding of proteins to the bacteria changes their physicochemical surface properties. These types of bacteria-protein interactions may play an important role in modulating host-parasite relationships.
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| 2. |
- Miörner, Håkan, et al.
(författare)
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Isoelectric points and surface hydrophobicity of Gram-positive cocci as determined by cross-partition and hydrophobic affinity partition in aqueous two-phase systems
- 1982
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Ingår i: Infection and Immunity. - 1098-5522. ; 36:1, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine streptococcal strains belonging to groups A, C, and G and 12 staphylococcal strains were investigated with respect to surface charge and hydrophobicity. Isoelectric points of the bacteria were determined by cross-partition experiments in dextran-polyethylene glycol two-phase systems containing charged polymers. The results obtained indicate that group A, C, and G streptococci have isoelectric points of pH 3.75 +/- 0.15 standard deviation. Staphylococci show an isoelectric point of around pH 2 and thereby differ markedly from the streptococci. Pretreatment of bacteria with human serum resulted in a significant change in the isoelectric points of streptococci. In a second series of experiments, an aqueous dextran-polyethylene glycol two-phase system containing polyethylene glycol palmitate or stearate was used to study the hydrophobic surface properties of the bacterial cells. The partition of the staphylococci was not influenced by the addition of up to 1% (wt/wt) polyethylene glycol palmitate or stearate, whereas the streptococci showed a large variation in affinity for polyethylene glycol-bound hydrophobic groups. The bacterial strains included in the study were also tested for uptake of human serum proteins. A positive correlation was found between the hydrophobic affinity of group A streptococci and the density of receptors for aggregated beta-2-microglobulin.
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| 3. |
- Miörner, Håkan, et al.
(författare)
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Lipoteichoic acid is the major cell wall component responsible for surface hydrophobicity of group A streptococci
- 1983
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Ingår i: Infection and Immunity. - 1098-5522. ; 39:1, s. 336-343
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of lipoteichoic acid (LTA) to the hydrophobic surface properties of group A streptococci was investigated in aqueous dextran-polyethylene glycol two-phase systems. Enzymatic digestions were performed to characterize the hydrophobic surface structure. The results obtained indicated that LTA is a major factor responsible for the hydrophobic character of the cell surface of group A streptococci. This was further supported by the similarity of partition in polymer two-phase systems between whole group A streptococci and tritiated LTA extracted from a group A streptococcal strain. Surface LTA was also determined on intact organisms by a new method measuring the adsorption of antibodies to LTA to the bacterial surface. A correlation was found between the content of surface LTA and the hydrophobicity of the group A streptococci. We conclude that surface-associated LTA is the major factor determining surface hydrophobicity of group A streptococci.
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| 4. |
- Svanborg Eden, C, et al.
(författare)
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Influence of adhesins on the interaction of Escherichia coli with human phagocytes
- 1984
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Ingår i: Infection and Immunity. - 1098-5522. ; 44:3, s. 672-680
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Tidskriftsartikel (refereegranskat)abstract
- The fitness between bacterial adhesins and target cell receptors, determining bacterial adherence to epithelial cells in urinary tract infections, was shown to influence also the interaction with human polymorphonuclear leukocytes (PMNL). Two sets of homogenic strains, constructed to express either, both, or none of the globotetraosylceramide-sensitive (GS) adhesins specific for globoseries glycolipid receptors or the mannose-sensitive (MS) adhesins inhibited by alpha-methyl mannoside were compared regarding charge, hydrophobicity, and binding to PMNL. The mutants of a hydrophilic pyelonephritis strain required MS adhesins for binding to and activation of the PMNL. Removal of the MS adhesins from the mutant carrying both MS and GS adhesins abolished chemiluminescence and binding. A pronounced chemiluminescence reaction was induced by the hydrophobic strain without GS or MS adhesins . Transformants of this strain expressing the MS adhesin bound to and activated the PMNL. Poor binding and activation were found with mutants and transformants carrying only the GS adhesins . The improved reactivity after coating of the PMNL with the appropriate receptor glycolipid supported the previously reported absence of globoseries glycolipids in those cells as the reason for the refractoriness to bacteria with GS adhesins . The mechanism of binding, which improves epithelial cell adhesion, may prevent binding to PMNL, thus improving the survival of Escherichia coli in the kidney.
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