Functional activities of Lactobacillus probiotics: Genetic mandate

The lactobacilli are important inhabitants of the intestinal tract of man and animals. Considerable evidence has implicated them in a number of potentially beneficial roles including immunostimulation, pathogen exclusion, production of bioactive materials, and general intestinal health. Opportunities now abound for incorporation of lactobacilli into functional foods, dietary adjuncts, and health-related products. Over the past decade, developments in the molecular taxonomy of lactobacilli have identified six distinct species within the group previously designated Lactobacillus acidophilus. It remains an important challenge to understand the intestinal roles, activities, and interactions of the individual species, as well as the group at large. In this context, genetic characterization and manipulation of lactobacilli are essential to unequivocally define their contributions to the intestinal microbiota and ultimately control their unique and potentially beneficial properties. This presentation will examine gene systems and regulatory controls of lactobacilli that may be important to their activity, stability, and gastrointestinal functionality. The genetic tools and strategies currently available for characterization and manipulation of lactobacilli will be discussed relative to future targets for probiotic applications. From this framework, new opportunities for the development of safe and effective probiotics will be presented. (C) 1998 Elsevier Science Ltd. All rights reserved.