Figure 1.
Relationship between PROP phenotype and gustin gene and TAS2R38 polymorphisms.
PROP threshold (A) and bitterness intensity ratings (3.2 mM) (B) of individuals with genotypes AA, AG and GG of gustin (CA6) polymorphism rs2274333 (A/G), and of individuals with genotypes PAV/PAV, PAV/AVI and AVI/AVI of TAS2R38. All values are mean (± SEM). n=63. Different letters indicate significant difference (p≤0.0471; Newman-Keuls test subsequent to main effects ANOVA).
Figure 2.
Relationship between density of fungiform papillae and gustin gene and TAS2R38 polymorphisms.
Mean values ± SEM of density of fungiform papillae (No. /cm2) on the anterior part of the tongue of individuals with genotypes AA, AG and GG of gustin (CA6) polymorphism rs2274333 (A/G) (upper graph) and of individuals with genotypes PAV/PAV, PAV/AVI and AVI/AVI of TAS2R38 (lower graph). n=63. Different letters indicate significant difference (p≤0.0379; Newman-Keuls test subsequent to main effects ANOVA). Examples of the 6-mm-diameter stained area of the tongue tip where measures were taken are shown to the right of the graphs.
Figure 3.
Relationship between fungiform papillae diameter and gustin gene and TAS2R38 polymorphisms.
Mean values ± SEM of the diameter of fungiform papillae of individuals with genotypes AA, AG and GG of gustin (CA6) polymorphism rs2274333 (A/G) (upper graph) and of individuals with genotypes PAV/PAV, PAV/AVI and AVI/AVI of TAS2R38 (lower graph). n=63. Different letters indicate significant difference (p≤ 0.00053; Newman-Keuls test subsequent to main effects ANOVA).
Figure 4.
Relationship between fungiform papillae distortion and gustin gene polymorphism.
Standard deviation (SD) of diameter of fungiform papillae (A) and percentage of distorted fungiform papillae (B) in individuals with genotypes AA, AG and GG of gustin (CA6) polymorphism rs2274333 (A/G). All values are mean (± SEM). n=63. Different letters indicate significant difference (p≤0.00019; Newman-Keuls test subsequent to one-way ANOVA).
Figure 5.
Effect of gustin gene polymorphism rs2274333 (A/G) in vitro experiments.
A, Number of cells, expressed as percentage of control, after treatments with saliva of subjects with genotype AA (n=12) or with saliva of subjects with genotype GG (n=12); different letters indicate significant difference (p=0.0135; Student’s t test). B, Fluorescence emission at a wavelength of 590 nm obtained from cells treated for 72 h with saliva of subjects with genotype AA, genotype GG and control; n=12; different letters indicate significant differences (p≤0.00023; Newman-Keuls test subsequent to one-way ANOVA). C, Fluorescence emission at a wavelength of 590 nm obtained from cells treated for 72 h with the two iso-forms of isolated gustin (gustin Ser90 or gustin Gly90) + Zn, control + Zn, or control; n=33; different letters indicate significant differences (p≤0.00067; Newman-Keuls test subsequent to one-way ANOVA).