Equilibrium analysis of binding of Candida albicans to human buccal epithelial cells

1990 ◽  
Vol 36 (5) ◽  
pp. 336-340 ◽  
Author(s):  
William Staddon ◽  
Tom Todd ◽  
Randall T. Irvin
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Copy Number ◽  
Incubation Temperature ◽  
Temperature Shift ◽  
Equilibrium Analysis ◽  
High Copy Number ◽  
Buccal Epithelial Cells ◽  
Low Copy Number ◽  
Receptor Interactions

The effect of growth temperature on the binding of Candida albicans to human buccal epithelial cells (BECs) was examined using an equilibrium of binding analysis. Candida albicans was cultured in M9 medium either for 12 h at 25 °C or for 9 h at 25 °C and then shifted to 37 °C for 3 h. The temperature shift did not result in germ tube formation; however, the adherence of C. albicans to BECs was altered. Shifting temperature increased the yeast's ability to bind to BECs. A Langmuir adsorption isotherm was used to calculate the maximum number of available binding sites (N) and the apparent association constants of binding (Ka) for all resolvable adhesin–receptor interactions. Three classes of adhesin–receptor interactions were resolved when the yeast was cultured at 25 °C and included a low copy number site (N = 3.0 cfu/BEC; Ka = 2.11 × 10−6 mL/cfu), a medium copy number site (N = 23.6 cfu/BEC, Ka = 8.21 × 10−7 mL/cfu), and a high copy number site (N = 91.7 cfu/BEC, Ka = 3.35 × 10−8 mL/cfu). Two classes of adhesin–receptor interactions were resolved when the incubation temperature was shifted to 37 °C: a low copy number site (N = 4.5 cfu/BEC, Ka = 3.98 × 10−6 mL/cfu) and a high copy number site (N = 150.5 cfu/BEC, Ka = 8.47 × 10−8 mL/cfu). Augmented C. albicans adherence to BECs due to the elevated growth temperatures appears to result from a temperature-regulated alteration in the C. albicans adhesin that recognizes a high copy number receptor site with relatively low affinity.

The binding of Pseudomonas aeruginosa outer membrane ghosts to human buccal epithelial cells

1986 ◽  
Vol 32 (2) ◽  
pp. 160-166 ◽  
Author(s):  
P. Doig ◽  
A. L. Franklin ◽  
R. T. Irvin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Epithelial Cells ◽  
Outer Membrane ◽  
Copy Number ◽  
Electron Microscopic Examination ◽  
Equilibrium Analysis ◽  
Metabolic Effects ◽  
Electron Microscopic ◽  
Buccal Epithelial Cells ◽  
Number Class

The binding of outer membrane (OM) ghosts derived from Pseudomonas aeruginosa strain 492c to human buccal epithelial cells (BECs) was examined. Electron microscopic examination of the binding of OM ghosts to BECs revealed direct OM ghost–BEC interaction. Equilibrium analysis of the binding of OM ghosts to trypsinized BECs employing the Langmuir adsorption isotherm indicated the number of binding sites (iV) to be 1.3 × 10−1 μg protein per BEC with an apparent association constant (Ka) of 3.4 × 10−2 mL/μg protein. The Langmuir analysis of binding of OM ghosts to untrypsinized BECs was complex, suggesting two possible classes of receptors, a high affinity–low copy number class (Ka, 1.8 × 10−2 mL/μg protein; N, 8.6 × 10−5 μg protein per BEC) and a low affinity – high copy number class(Afa, 3.7 × 10−3 mL/μg protein; N, 9.2 × 10−4 μg protein per BEC). Sugar inhibition studies incorporating D-galactose enhanced binding to each BEC type. N-Acetylneuraminic acid and N-acetyl-glucosamine both enhanced binding of OM ghosts to untrypsinized BECs, while inhibiting binding to trypsinized BECs. D-Arabinose inhibited binding to both BEC types. Binding of OM ghosts to both BEC types was greatly inhibited by D-fucose, while L-fucose only greatly inhibited binding to untrypsinized BECs. These sugar inhibition data demonstrated a difference in the binding of OM ghosts to trypsinized and untrypsinized BECs and possibly reveal the nature of the receptor(s), free of possible bacterial metabolic effects. These data indicated that OM ghosts from 492c appear to bind to BECs in a similar manner to the intact bacteria and represent a simple model system to study the adhesion of P. aeruginosa to BECs.

Adhesion of Pseudomonas aeruginosa to human buccal epithelial cells: evidence for two classes of receptors

1985 ◽  
Vol 31 (6) ◽  
pp. 563-569 ◽  
Author(s):  
David W. McEachran ◽  
Randall T. Irvin
Keyword(s):  
Binding Sites ◽  
Copy Number ◽  
Alginic Acid ◽  
High Copy Number ◽  
Acetylneuraminic Acid ◽  
High Affinity ◽  
Buccal Epithelial Cells ◽  
Low Copy Number ◽  
Inhibition Data ◽  
Number Class

The adhesion of Pseudomonas aeruginosa strain 492c to trypsinized and untrypsinized buccal epithelial cells (BECs) was studied. Kinetic analysis of the adhesion data, employing a Langmuir absorption isotherm, indicated the presence of two classes of binding sites on untrypsinized BECs: a high affinity – low copy number site (apparent association constant (Ka ≈ 1.57 × 10−8 mL/cell with ca. 29 binding sites/cell) and a low affinity – high copy number class of binding sites (Ka ≈ 4.78 × 10−10 mL/cell with ca. 264 binding sites/cell). The low affinity – high copy number class of sites was found to be trypsin sensitive. A single class of binding sites was found on trypsinized BECs exhibiting a high affinity – low copy number (Ka ≈ 3.70 × 10−7 mL/cell with ca. 31 binding sites/cell). Positive cooperativity in binding of P. aeruginosa strain 492c to the low affinity – high copy number class site on untrypsinized BECs was demonstrated by analysis of Hill plots of the adhesion data. Sugar inhibition data using a preincubation methodology showed an inhibition of adhesion to trypsinized BECs in the presence of N-acetylneuraminic acid and D-arabinose, while these same two sugars enhanced adhesion to untrypsinized BECs. D-Galactose and N-acetylglucosamine enhanced adhesion to both types of BECs though the latter did to different extents. D-Fucose only inhibited adhesion to untrypsinized BECs. Without preincubation the sugar inhibition data indicated that N-acetylglucosamine had no effect on adhesion while N-acetylneuraminic acid and D-fucose both enhanced adhesion to both types of BECs. D-Arabinose had a slight inhibitory effect on adhesion, while D-galactose had a slight enhancing effect to both cell types, but to different levels. This sugar data suggests a difference in the receptors on the two types of BECs, but the possibility of metabolism of these sugars by P. aeruginosa requires one to interpret this data with caution. Flagella were shown not to be involved in adhesion, while the alginic acid of the capsule was implicated. The low copy number binding site is speculated to be a pili-binding site, while the high copy number class of binding sites is proposed to involve a lectin which binds alginic acid.

scholarly journals Inhibition of adherence of the yeast Candida albicans to buccal epithelial cells by synthetic aromatic glycoconjugates

2018 ◽  
Vol 160 ◽  
pp. 82-93 ◽  
Author(s):  
Harlei Martin ◽  
Mairead Mc Govern ◽  
Lorna Abbey ◽  
Aisling Gilroy ◽  
Stephanie Mullins ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Buccal Epithelial Cells

Adhesin - receptor interactions in the attachment ofCandida albicansto host epithelial cells

1995 ◽  
Vol 73 (S1) ◽  
pp. 1147-1153 ◽  
Author(s):  
L. Julia Douglas
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Blood Group Antigen ◽  
Receptor Interaction ◽  
Environmental Signals ◽  
Yeast Form ◽  
Adhesion Receptor ◽  
Receptor Interactions ◽  
Fimbrial Adhesin ◽  
Protein Portion

The ability of Candida albicans to adhere to a variety of host surfaces is thought to be an important factor in the pathogenesis of candidosis. Adhesion of the yeast form of the fungus to epithelial cells can involve several kinds of adhesion – receptor interaction. Yeast adhesins are typically mannoproteins associated with fibrils or fimbriae on the fungal surface. Lectinlike interactions have been identified between the protein portion of two mannoprotein adhesins and glycosides containing L-fucose or N-acetylglucosamine. The fucoside-binding adhesin has been purified and shown to have an affinity for glycosphingolipid receptors carrying the H blood-group antigen. A fimbrial adhesin has also been described that binds to gangliosides containing a βGalNAc(1–4)βGal disaccharide sequence. Other mannoprotein adhesins proposed recently include the factor 6 epitope present on serotype A strains of C. albicans and an integrin analogue. Adhesin expression appears to be regulated by a number of environmental signals, including osmolarity and the availability of iron and sugars. Additional adhesion-dependent signals might trigger further responses such as the initiation of morphogenesis. Key words: Candida albicans, yeast adhesion, epithelial cell adhesion.

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