EFFECTS OF ORALLY ADMINISTERED ENTEROCOCCUS FAECIUM ON THE IMMUNE SYSTEMIC RESPONSE AND INTESTINAL EPITHELIAL STRUCTURE IN BALB/C MICE IMMUNIZED BY BOVINE Î’-LACTOGLOBULIN

Objective: Determine the effect of Enterococcus faecium on systemic immune response and its effect on the intestinal epithelial structure in the Balb/c mice. Methods: Thirty Balb/c mice were dispatched in three lots of 10 mice each. During an initial period of 18 days, the animals from the first lot received via an oral way suspension of 0,3 mL containing 108 ufc/mL of Enterococcus faecium,for the second and the third lot received 0,3 mL of a saline solution. In a second period of time, mice from the first and second lots were immunised via parenteral way using β-Lg. Then they were sacrified on the 50th day after the end of the first period (18 days). The level of IgG anti-β-Lg was determined in the sera by the ELISA, and histologic studies were conducted on the jejunum fragments. Results: Our results show that anti β-Lactoglobulin IgG titers were significantly reduced in immunized mice that received the Enterococcus faecium (1/280th) (***p<0,001). The histological studies of the intestinal epithelium shows long intestinal villi (53,88 ± 1,38µm) with diminished intra-epithelial lymphocytes. Conclusion: The study shows that Enterococcus faecium PC4.1 may help protect the intestinal epithelium integrity by maintaining the structure of the villi and has the ability to decrease the systemic immune response to β-lactoglobulin

Screening of strains of lactococci isolated from Egyptian dairy products for their proteolytic activity

International audienceA collection of cocci isolates (293) obtained from traditional Egyptian dairy products collected from four Egyptian regions yielded 151 Lactic Acid Bacteria (LAB) cocci isolates. Among them, 24 isolates were characterized as highly proteolytic. SDS-PAGE showed that 6 isolates were the most proteolytically active, which were classified into Enterococcus faecalis HH22 (4 isolates) and Enterococcus faecium DO623 (2 isolates). The proteolytic activity of Ent. faecalis was higher than that of Ent. faecium (particularly on [beta]-casein). The maximal degradation of milk proteins was achieved at pH 6.5-7.2 (Ent. faecalis) or pH 6.5 (Ent. faecium) and at 42 °C for both strains. The proteolytic activities of the two strains were inhibited mostly by the presence of EDTA, showing that their proteases belong mainly to metalloproteases. A slight inhibition of proteolysis by PMSF in the case of Ent. faecalis HH22 suggests a limited inclusion of serine proteases in its protease system

Characterization of a new isolate of Lactobacillus fermentum IFO 3956 from Egyptian Ras cheese with proteolytic activity

International audienceMore than 200 isolates were obtained from 15 Egyptian traditional dairy products (Domiatti cheese, Ras cheese and Rayeb milk) collected from local markets of Alexandria, Tanta and Kafr El-Sheikh. Examination with optical microscope of these dairy samples allowed to classify 92 bacilli, 64 of which were identified as lactobacilli. The proteolytic activity of lactobacilli isolates was tested on skim milk agar. Eight isolates showing a high proteolytic activity were further tested on UHT skim milk. The strain showing the highest proteolytic activity was purified and identified as Lactobacillus fermentum IFO 3656. The specific proteolytic activity of this strain and the factors affecting it (pH, temperature and presence of inhibitors) were studied. The proteolysis targeted mainly caseins (73% of whole casein), especially beta-casein (85%). Smaller portions of whey proteins were proteolyzed (20%) essentially beta-lactoglobulin. The proteolysis process gave rise to medium-sized peptide populations. The optimum conditions for the proteolysis activity of the studied strains were pH 6.5 and 37 A degrees C. Proteolytic activities were very slightly affected by the increase of the temperature to 42 A degrees C or the pH to 8.2. The protease system of Lactobacillus fermentum IFO 3956 is most probably composed from a high amount of metalloproteases and small amount of cysteine and serine protease

Potential use of lactic acid bacteria for reduction of allergenicity and for longer conservation of fermented foods

The interest of consumers for diverse fermented foods has increased in recent years thanks to the positive perception of their impact on consumer health considered as beneficial. Hence, there is an evident need for search of novel ways and for new food preservation agents of natural origins. In this aspect, lactic acid bacteria are very good candidates. It should be highlighted also that the onset of food allergies is rising significantly in recent years. The reduction of the immunoreactivity of food proteins could be achieved thanks to pre-prandial proteolysis occurring in fermented dairy (and other food) systems changing the allergen presentation or cleaving the allergenic protein epitopes, and produce hypoallergenic products.Fil: El-Ghaish, Shady. Institut National de la Recherche Agronomique; FranciaFil: Ahmadova, Aynur. Institut National de la Recherche Agronomique; FranciaFil: Hadji-Sfaxi, Imen. Institut National de la Recherche Agronomique; FranciaFil: El Merchefi, Kamel Eddine. Institut National de la Recherche Agronomique; Francia. Université d’Oran. Département de biologie. Laboratoire de Physiologie de la Nutrition et sécurité Alimentaire; ArgeliaFil: Bazukyan, Inga. Yerevan State University. Faculty of Biology; ArmeniaFil: Choiset, Yvan. Institut National de la Recherche Agronomique; FranciaFil: Rabesona, Hanitra. Institut National de la Recherche Agronomique; FranciaFil: Sitohy, Mahmoud. Institut National de la Recherche Agronomique; Francia. Zagazig University. Faculty of Agriculture. Biochemistry Department; EgiptoFil: Popov, Yuri G.. Yerevan State University. Faculty of Biology; ArmeniaFil: Kuliev, Akif A.. Baku State University. Biotechnical and Biochemistry Chair; AzerbaiyánFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Chobert, Jean-Marc. Institut National de la Recherche Agronomique; FranciaFil: Haertle, Thomas. Institut National de la Recherche Agronomique; Franci