Conditions affecting cell surface properties of human intestinal bifidobacteria

Abstract

The cell surface properties of human intestinal bifidobacteria have been characterized for 30 strains isolated from a fecal sample. Strain identification to the species level was obtained by restriction analysis of the amplified 16S rRNA gene and confirmed by DNA/DNA reassociation experiments. The isolates were grouped in four genetically homogeneous clusters whose members belonged to Bifidobacterium bifidum, Bifidobacterium adolescentis, Bifidobacterium longum and Bifidobacterium pseudocatenulatum species. Cell surface properties of Bifidobacterium strains were evaluated by determining the level of hydrophobicity, adhesion to hydrocarbons and contact angle measurements, and their autoaggregation ability. The results showed high and homogeneous level of hydrophobicity in all tested strains when contact angle measurements values were considered. On the contrary, autoaggregation assays and bacterial adhesion to hydrocarbons detected interesting differences in cell surface properties among the tested Bifidobacterium strains. The highest levels of autoaggregation, detected in B. bifidum and B. adolescentis strains, were strictly dependent on the pH of the medium. Moreover, protease treatment experiments suggested that proteins had a key role in the autoaggregating ability of B. bifidum and B. adolescentis strains.

Molecular characterization of Bifidobacterium longum biovar longum NAL8 plasmids and construction of a novel replicon screening system

“…Nevertheless, no more than two co-resident plasmids of a single strain have been fully characterized so far (Corneau et al 2004;Lee and O'Sullivan 2006;Park et al 1997). That is why we decided to perform a molecular characterization of the three plasmids harbored by B. longum NAL8, a strain isolated as a member of the predominant bifidobacterial population in a single fecal sample from a healthy elderly woman (Canzi et al 2005).…”

“…This study reports molecular characterization and computational sequence analysis of three plasmids in the human intestinal isolate B. longum biovar longum NAL8 (Canzi et al 2005) with an in silico comparison of all the Bifidobacterium plasmid sequences available to date.…”

Evaluation of probiotic potential of lactic acid bacteria isolated from traditional Malaysian fermentedBambangan(Mangifera pajang)

“…The bacterial adhesion to the hydrocarbon assay, which determines the bacterial cell surface hydrophobicity, was performed according to the method reported by Canzi, Guglielmetti, Mora, Tamagnini, and Parini (2005). The LAB strains were inoculated into PBS and the same volume of n-hexadecane was added and incubated at room temperature for an hour.…”

In vitro evaluation of adhesion and aggregation abilities of four potential probiotic strains isolated from guppy (Poecilia reticulata)

“…Autoaggregation of probiotic strains appeared to be necessary for adhesion to intestinal epithelial cells and the ability to coaggregate with other bacteria such as pathogens may form a barrier that prevents colonization by pathogenic microorganisms (Boris et al 1997;Del Re et al 1998). Adherence of bacterial cells is usually related to cell surface characteristics (Bibiloni et al 2001;Canzi et al 2005). Physicochemical characteristics of the cell surface such as hydrophobicity may affect autoaggregation and adhesion of bacteria to different surfaces (Wadström et al 1987;Perez et al 1998;Del Re et al 1998).…”