from indigenous fermented foods and human gut ... - Thapar University
from indigenous fermented foods and human gut ... - Thapar University
from indigenous fermented foods and human gut ... - Thapar University
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129<br />
Chapter V Discussion<br />
hydrophobicity. Furthermore, it was suggested that bacteria with high hydrophobic surfaces<br />
might reversibly adhere to intestinal cells (Del Re et al., 2000; Ehrmann et al., 2002).<br />
However, other authors have reported no correlation between hydrophobicity <strong>and</strong> adhesion<br />
(Conway <strong>and</strong> Reginald, 1989; Vinderola et al., 2004). The values of the microbial adhesion<br />
to solvents test obtained with n-hexadecane reflected the hydrophobicity of the bacterial<br />
surface, whereas the values obtained with chloroform <strong>and</strong> ethyl acetate in this test can be<br />
regarded as a measure of the electron donor (basic) <strong>and</strong> electron acceptor (acidic)<br />
characteristics of the cell walls, respectively (Bellon-Fontaine et al., 1996).<br />
The two selected L. casei strains (LAM-1 <strong>and</strong> LAM-2) studied showed high affinity<br />
for the hydrophobic solvent n-hexadecane <strong>and</strong> for the polar solvents chloroform <strong>and</strong> ethyl<br />
acetate. This indicated, the surface of these strains was able to simultaneously interact with<br />
charged (hydrophilic) <strong>and</strong> non-charged (hydrophobic) molecules. A relationship between<br />
adhesion to intestinal mucus <strong>and</strong> amphiphatic characteristics has been also previously<br />
described (Collado et al., 2006) very recently. Thus, it appears that this bivalent nature of the<br />
cell surface of the L. casei strains (this study) may point towards a high adhesion to intestinal<br />
epithelial cells, as indicated by the adhesion assay results.<br />
Adsorption at surfaces is a non-selective process that is only a part of the multistep<br />
phenomenon of adhesion. Nevertheless, it is still important, as it brings two surfaces close<br />
enough to permit possible adhesions <strong>and</strong> cell receptors to interact with each other (Gordon et<br />
al., 1985; Abraham et al., 1999). A great variability in adhesion to Caco2 cells was found<br />
among L. casei strains. One of the strains (L. helveticus LKH-5) was non-adhesive, another<br />
was moderately adhesive (L. fermentum Lamec-29) <strong>and</strong> two strains (L. delbruckeii LKH-2,<br />
<strong>and</strong> LKH-3) were strongly adhesive. Strains which showed poor adhesion to Caco2 (L.<br />
helvictus LKH-5 <strong>and</strong> L. fermentum Lamec-29) showed variable values of adhesion to n-
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