Seventy strains of Bifidobacterium globosum isolated from gastrointestinal tracts of different animals were studied. Strains were grown at temperatures ranging from 25 to 46.5 o C in order to examine changes both in the expression of bifidobacterial outer proteins (BIFOPs) and in their hydrophobic properties. It was observed that the expression of BIFOPs found on the cell-surface changes according to growth temperature, with quantitative and/or qualitative variations. Generally speaking, it was observed that BIFOP expression at low-growth temperature was considerably attenuated, while at medium- and high-growth temperature it increased. Furthermore, at high-growth temperatures, the presence of a new common protein was detected in all the strains studied. Cells from B. globosum strains grown under different temperature conditions were studied in terms of their cellular hydrophobicity properties. At medium-growth temperature, the cell hydrophobicity was strictly correlated with BIFOP expression, while at low and high-growth temperatures, the presence of BIFOP only partially influenced the hydrophobic features.
Effet de la temperature de croissance sur la biosynthese de la paroi de Bifidobacterium globosum. Soixante-dix souches de Bifidobacterium globosum isolees du tube digestif de plusieurs animaux ont ete l'objet de cette etude. L'effet d'une gamme de temperatures de culture de 25 a 46,5<space> o C a ete observe sur la composition des proteines, BIFOP (bifidobacterial outer protein), specifiques de la paroi bacterienne des bifidobacteries. et sur l'hydrophobicite des bacteries. Nous avons montre que la biosynthese des BIFOP est dependante de la temperature de croissance. En effet, elle est tres faible a basse temperature (25-30 o C) et augmente avec la temperature de croissance. En outre, nous avons mis en evidence chez toutes les souches etudiees, une nouvelle proteine de 48.5<space>kDa, appelee HTB (high temperature BIFOP). L'hydrophobicite de quelques souches a aussi ete etudiee apres croissance des bacteries a differentes temperatures. Il semble que cette hydrophobicite soit principalement due aux BIFOP lorsque les bacteries se developpent a 37<space> o C; si les bacteries croissent a des temperatures inferieures ou superieures a 37<space> o C, les BIFOP semblent contribuer dans une proportion bien plus faible a l'hydrophobicite cellulaire.