Physicochemical roles of soluble metal cations in the outer membrane of Escherichia coli K-12

1986 ◽  
Vol 32 (7) ◽  
pp. 594-601 ◽  
Author(s):  
F. G. Ferris ◽  
T. J. Beveridge
Keyword(s):  
Cell Surface ◽  
Outer Membrane ◽  
Metal Binding ◽  
Metal Salt ◽  
Binding Capacity ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Metallic Ions ◽  
Intact Cells ◽  
K 12

Atomic absorption spectroscopy of isolated native and EDTA-modified (lipopolysaccharide-depleted) outer membrane revealed trace amounts of potassium, manganese, and iron (1.0–7.0 nmol/mg dry weight outer membrane). Sodium, magnesium, and calcium were approximately one order of magnitude more plentiful, but EDTA-modified outer membrane was deficient in calcium. When metal-binding assays were conducted to find the binding capacity of native and EDTA-modified outer membrane, potassium bound poorly compared with sodium. However, there was no difference in the binding of these ions between the OM preparations. In contrast, reduced amounts of magnesium, calcium, manganese, and iron III bound to the EDTA-modified OM. Partitioning of intact cells in a biphasic dextran–polyethyleneglycol system indicated that the reduced lipopolysaccharide content of the EDTA-modified outer membrane increased the hydrophobicity of the cell surface. Exposure of control and EDTA-treated cells to divalent metal salt solutions before phase partitioning also increased cell surface hydrophobicity. Freeze-etching showed that sodium ions had no effect on the membrane fractures observed in control cells, but with EDTA-treated cells, this cation increased the occurrence of small outer membrane fractures (plateaus) which are characteristic of EDTA treatment. Both magnesium and manganese increased the frequency of outer membrane cleavage in control cells, whereas calcium did not. In contrast, all three divalent metallic ions increased the frequency and extent of cleavage in the outer membrane of EDTA-treated cells.

scholarly journals Outer Membrane Changes in a Toluene-Sensitive Mutant of Toluene-Tolerant Pseudomonas putidaIH-2000

1999 ◽  
Vol 181 (15) ◽  
pp. 4493-4498 ◽  
Author(s):  
Hideki Kobayashi ◽  
Hideto Takami ◽  
Hisako Hirayama ◽  
Kuniko Kobata ◽  
Ron Usami ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Membrane Proteins ◽  
Cell Surface ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Dodecanoic Acid ◽  
Sensitive Mutant ◽  
Membrane Changes

ABSTRACT We isolated a toluene-sensitive mutant, named mutant No. 32, which showed unchanged antibiotic resistance levels, from toluene-tolerantPseudomonas putida IH-2000 by transposon mutagenesis with Tn5. The gene disrupted by insertion of Tn5 was identified as cyoC, which is one of the subunits of cytochrome o. The membrane protein, phospholipid, and lipopolysaccharide (LPS) of IH-2000 and that of mutant No. 32 were examined and compared. Some of the outer membrane proteins showed a decrease in mutant No. 32. The fatty acid components of LPS were found to be dodecanoic acid, 2-hydroxydodecanoic acid, 3-hydroxydodecanoic acid, and 3-hydroxydecanoic acid in both IH-2000 and No. 32; however, the relative proportions of these components differed in the two strains. Furthermore, cell surface hydrophobicity was increased in No. 32. These data suggest that mutation of cyoC caused the decrease in outer membrane proteins and the changing fatty acid composition of LPS. These changes in the outer membrane would cause an increase in cell surface hydrophobicity, and mutant No. 32 is considered to be sensitive to toluene.

scholarly journals Evaluation of Relative Yeast Cell Surface Hydrophobicity Measured by Flow Cytometry

2005 ◽  
Vol 13 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Lisa Colling ◽  
Richard N. Carter ◽  
Michael Essmann ◽  
Bryan Larsen
Keyword(s):  
Flow Cytometry ◽  
Cell Surface ◽  
Binding Capacity ◽  
Cell Surface Hydrophobicity ◽  
Fungal Growth ◽  
Surface Hydrophobicity ◽  
Growth Conditions ◽  
Yeast Cells ◽  
Appreciable Effect ◽  
Polystyrene Microspheres

Objective:To develop an efficient method for evaluating cell surface hydrophobicity and to apply the method to demonstrate the effects of fungal growth conditions on cell surface properties.Methods:Yeast isolates were suspended in phosphate-buffered saline and mixed with deep blue-dyed polystyrene microspheres. Flow cytometry was used to detect the degree of microsphere binding to yeast cells. Different strains of yeast were compared for intrinsic microsphere binding activity and changes in growth conditions were invoked to modify the relative surface hydrophobicity.Results:Commercially available blue-dyed polystyrene microspheres showed strong fluorescence in the FL3 channel, whereas yeast cells did not show appreciable FL3 fluorescence. Microspheres and yeast were generally distinguishable on the basis of size revealed by forward light scatter. This method showed a wide variation in intrinsic cell surface hydrophobicity amongCandida albicansstrains. Likewise, variation in hydrophobicity of non-albicans yeast species was observed. Growth on solid media, incubation at 25°C, or 250 mg/dl glucose concentration increased hydrophobicity compared with growth in liquid media, incubation at 37°C, or 50 mg/dl glucose, respectively. Growth in1×10−9M estradiol had no appreciable effect on hydrophobicity.Conclusions:Stained latex microspheres fluoresced in the FL3 channel of the flow cytometer and bound to yeast cells to an extent related to the surface hydrophobicity of the yeast. Binding detected by flow cytometry showed that clinical yeast isolates varied in intrinsic binding capacity and this binding ability was altered by different growth conditions. The implications for virulence regulation among yeast isolates are discussed.

Autecology of scum producing bacteria

1998 ◽  
Vol 37 (4-5) ◽  
pp. 527-530 ◽  
Author(s):  
Hilde Lemmer ◽  
George Lind ◽  
Margit Schade ◽  
Birgit Ziegelmayer
Keyword(s):  
Wastewater Treatment ◽  
Cell Surface ◽  
Wastewater Treatment Plants ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Residence Times ◽  
Loading Conditions ◽  
Emulsifying Activity ◽  
Substrate Preferences

Non-filamentous hydrophobic scum bacteria were isolated from scumming wastewater treatment plants (WWTP) by means of adhesion to hydrocarbons. They were characterized with respect to taxonomy, substrate preferences, cell surface hydrophobicity, and emulsification capability. Their role during flotation events is discussed. Rhodococci are selected by hydrolysable substrates and contribute to flotation both by cell surface hydrophobicity and emulsifying activity at long mean cell residence times (MCRT). Saprophytic Acinetobacter strains are able to promote flotation by hydrophobicity and producing emulsifying agents under conditions when hydrophobic substrates are predominant. Hydrogenophaga and Acidovorax species as well as members of the Cytophaga/Flavobacterium group are prone to proliferate under low loading conditions and contribute to flotation mainly by emulsification.

Phenol and n-alkanes (C12 and C16) utilization: influence on yeast cell surface hydrophobicity

2008 ◽  
Vol 24 (9) ◽  
pp. 1943-1949 ◽  
Author(s):  
Łukasz Chrzanowski ◽  
Katarzyna Bielicka-Daszkiewicz ◽  
Mikołaj Owsianiak ◽  
Andreas Aurich ◽  
Ewa Kaczorek ◽  
...  
Keyword(s):  
Cell Surface ◽  
Yeast Cell ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Yeast Cell Surface
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