title: Health-promoting properties exhibited by Lactobacillus helveticus strains.
abstract: Many strains belonging to lactobacilli exert a variety of beneficial health effects in humans and some of the bacteria are regarded as probiotic microorganisms. Adherence and capabilities of colonization by Lactobacillus strains of the intestinal tract is a prerequisite for probiotic strains to exhibit desired functional properties. The analysis conducted here aimed at screening strains of Lactobacillus helveticus possessing a health-promoting potential. The molecular analysis performed, revealed the presence of a slpA gene encoding the surface S-layer protein SlpA (contributing to the immunostimulatory activity of L. helveticus M 92 probiotic strain) in all B734, DSM, T80, and T105 strains. The product of gene amplification was also identified in a Bifidobacterium animalis ssp. lactis BB12 probiotic strain. SDS-PAGE of a surface protein extract demonstrated the presence of a protein with a mass of about 50 kDa in all strains, which refers to the mass of the S-layer proteins. These results are confirmed by observations carried with transmission electron microscopy, where a clearly visible S-layer was registered in all the strains analyzed. The in vitro study results obtained indicate that the strongest adhesion capacity to epithelial cells (HT-29) was demonstrated by L. helveticus B734, while coaggregation with pathogens was highly diverse among the tested strains. The percentage degree of coaggregation was increasing with the incubation time. After 5 h of incubation, the strongest ability to coaggregate with Escherichia coli was expressed by T104. The T80 strain demonstrated a significant ability to co-aggregate with Staphylococcus aureus, while DSM with Bacillus subtilis. For B734, the highest values of co-aggregation coefficient was noted in samples with Salmonella. The capability of autoaggregation, antibiotic susceptibility, resistance to increasing salt concentrations, and strain survival in simulated small intestinal juice were also analyzed.
authors.affiliation: Department of Fruits, Vegetables and Mushrooms Technology, Faculty of Food Science and Biotechnology, University of Life Sciences in Lublin, Lublin, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Skrzypczak
authors.affiliation: Department of Fruits, Vegetables and Mushrooms Technology, Faculty of Food Science and Biotechnology, University of Life Sciences in Lublin, Lublin, Poland.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Gustaw
authors.affiliation: Department of Biotechnology, Human Nutrition and Food Commodity Science, Faculty of Food Science and Biotechnology, University of Life Sciences in Lublin, Lublin, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Waśko
mesh_terms: D001422:Bacterial Adhesion; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D019073:HT29 Cells; D006293:Health Promotion; D006801:Humans; D007422:Intestines / Q000382:microbiology; D052198:Lactobacillus helveticus / Q000502:physiology*; D019936:Probiotics