LABHEALTH · Novel applications of lactic acid bacteria to improve food safety and health

Final Activity Report Summary - LABHEALTH (Novel applications of lactic acid bacteria to improve food safety and health)

LABHEALTH is a Marie Curie Early Stage Research training action (MEST-CT-2004-514428) aimed to establish the scientific basis for the development of novel applications of Lactic acid bacteria (LAB) to improve food safety and health. Based on a solid disciplinary, and the creation of new inter-sectorial training networks, it integrated 12 specific and interdisciplinary projects. The Early stage researches (ESRs) from nine European countries and one third country (Brazil) participated to the project. The project covered 5 full PhD and seven short term programmes with four twin PhDs; the overall duration of programmes was from 9 to 36 months. Both theoretical and experimental trainings were given to ESRs. The training program was based on doctoral training modules recognized by four graduate schools, was regularly updated by training courses of internationally recognised scientists. The training took place in one of the most developed research areas in Europe (Ile de France), the National Institute for Agricultural Research (INRA) - an inter-sectorial institute working for more than 50 years in agricultural research. LABHEALTH is a methodology to create progressively dynamic and recognized interdisciplinary science in the European research area by training young scientists by and through the research. The project aimed at increasing the knowledge on the cell surfaces of LAB in order to develop new applications such as: i) positive biofilms which would limit the settlement of pathogens on food or health equipment; and ii) new vaccines which would contribute to limit pathogen carriage by animals. Moreover, the project aimed to shed new light on the functions expressed in the Gastro intestinal tract (GIT) by LAB for either bacterial adaptation or bacteria-host interactions. Using molecular biology approaches and the up-to-date tools (sequence databases, computing facilities, transcriptomic, proteomic, and image analysis), we have been able to draw a more complex and integrated picture of LAB surfaces, factors involved in biofilm formation, bacterial behaviour in mammal GIT and developed a system to deliver DNA in eukaryotic cells and mice mucosa that can be used as DNA vaccines. The bacterial surface was studied at several levels: a) the extensive characterisation of major bacterial the cell surface components (peptidoglycan, techoic acids and exopolysaccharides) pointed out key factors that influence interaction with pathogenic bacteria, and revealed the existence of structural heterogeneity of positive biofilms; b) bacterial surface proteins were studied by applying in silico and molecular biology approaches. Advances in this field allowed the project to reveal the abundance and nature of the surface proteins as well as their functions in the overall physico-chemical properties of the cell surface and the adhesion to abiotic substates. Bacteria-host interactions studies pointed out adaptation and functions expressed of certain bacterial species in the digestive tube of mice. We defined the expression pattern of bacterial surface proteins of E. faecalis in the GIT of mice; and revealed that the digestive tract of mice induce physiological adaptations of a meat-born bacterium, reflected in bacterial cell shape, cytoplasmic and cell wall proteomic pattern changes. We have also explored the ability of a yoghurt bacterium to affect human natural defences and determined that certain strains exert immune modulation effects and inhibit the activation of the inflammatory responses in vitro. Regarding the mucosal DNA vaccine delivery vectors, we have developed a system based on L. lactis bacterium for DNA delivery into epithelial cells, and evaluated the efficacy of the system in mouse disease models for allergic responses to a major cow's milk allergen and influenza virus infection. The results generated in the project significantly expanded the knowledge on positive biofilms, bacteria-host interactions, and vaccine development.

Data: CORDIS, © European Union