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Since the early observations of Elie Metchnikoff, a wealth of experiments have described the use of selected microorganisms, mainly belonging to the lactic acid bacteria family, for the prevention or treatment of a variety of pathological situations. Nevertheless, the mechanisms underlying the proposed actions remain vastly unknown, partly as a consequence of the complexity of the gastro-intestinal ecosystem with which these biotherapeutic agents are expected to interact, but also because of the increasing variety of strains considered to have potential probiotic characteristics. During the past decades, however, the beneficial effect of specific strains in preventing or treating intestinal disorders has been substantiated by well-controlled clinical trials. Increasing evidence, including human studies, is also supporting the immunomodulatory role attributed to given lactic acid bacterial strains. The desire by consumers to use natural methods for health maintenance rather than long-term chemotherapeutic agents (i.e. antibiotics), linked to their expectation that food becomes a source of prolonged well-being, supports the speculation that the probiotic market will expand rapidly. Much of this growth will also depend on the reliability of claims that these products will bare. Therefore, the legislator will have to provide clear rules and regulations which will depend on measurable biomarkers and criteria based on scientific evidence. These commercial and legislative needs will hopefully provide scientists with the resources necessary to conduct the multidisciplinary research required to establish facts and mechanisms of action for carefully selected probiotic strains. These research results will probably be as essential for the positioning of probiotic preparations as either a food, a food supplement or as pharmaceutical preparation.

The potential of lactic acid bacteria as live vehicles for the production and delivery of therapeutic molecules is being actively investigated today. For future applications it is essential to be able to establish dose-response curves for the targeted biological effect and thus to control the production of a heterologous biopeptide by a live lactobacillus. We therefore implemented in Lactobacillus plantarum NCIMB8826 the powerful nisin-controlled expression (NICE) system based on the autoregulatory properties of the bacteriocin nisin, which is produced by Lactococcus lactis. The original two-plasmid NICE system turned out to be poorly suited to L. plantarum. In order to obtain a stable and reproducible nisin dose-dependent synthesis of a reporter protein (␤-glucuronidase) or a model antigen (the C subunit of the tetanus toxin, TTFC), the lactococcal nisRK regulatory genes were integrated into the chromosome of L. plantarum NCIMB8826. Moreover, recombinant L. plantarum producing increasing amounts of TTFC was used to establish a dose-response curve after subcutaneous administration to mice. The induced serum immunoglobulin G response was correlated with the dose of antigen delivered by the live lactobacilli.Lactic acid bacteria (LAB) are used worldwide in the preparation of fermented foods, including dairy products. They are also known for the potentially beneficial effects they may exert on the health of humans and animals (see, for example, reference 25). Their "generally recognized as safe" status (1), linked to their metabolic and technological properties, has recently led to their development as potential live-vaccine vehicles. Lactobacillus plantarum NCIMB8826 (17, 33) has been chosen for this purpose in our laboratory on the basis of its capability to persist in the mouse gastrointestinal and urogenital tracts (38). The ability to control the expression level of foreign proteins in LAB may offer certain advantages. However, while several controlled expression systems have been developed for Lactococcus lactis (9, 23), very few inducible promoters are available for lactobacilli: the xylR promoter from Lactobacillus pentosus (29), the ␣-amylase promoter from L. amylovorus (31), and the p-coumarate decarboxylase promoter from L. plantarum (4). One of the most promising lactococcal controlled expression systems is based on the autoregulatory properties of the L. lactis nisin gene cluster (7,23). Nisin is an antimicrobial peptide belonging to the family of lantibiotics (19) and is used as a natural preservative in the food industry (5). Nisin induces the transcription of the genes under control of the nisA and nisF promoters, via a two-component regulatory system (34, 37) consisting of the histidine protein kinase NisK and the response regulator NisR (14,21,22). A transferable nisin-controlled expression (NICE) system (24) based on the combination of the nisA promoter and the nisRK regulatory genes has recently been developed (7,20). It consists of two compatible replicons, a plasmid carrying the nisRK regulato...

Clinical practice guidelines (CPGs) for rare diseases (RDs) are scarce, may be difficult to identify through Internet searches and may vary in quality depending on the source and methodology used. In order to contribute to the improvement of the diagnosis, treatment and care of patients, Orphanet (www.orpha.net) has set up a procedure for the selection, quality evaluation and dissemination of CPGs, with the aim to provide easy access to relevant, accurate and specific recommendations for the management of RDs. This article provides an analysis of selected CPGs by medical domain coverage, prevalence of diseases, languages and type of producer, and addresses the variability in CPG quality and availability. CPGs are identified via bibliographic databases, websites of research networks, expert centres or medical societies. They are assessed according to quality criteria derived from the Appraisal of Guidelines, REsearch and Evaluation (AGREE II) Instrument. Only open access CPGs and documents for which permission from the copyright holders has been obtained are disseminated on the Orphanet website. From January 2012 to July 2015, 277 CPGs were disseminated, representing coverage of 1,122 groups of diseases, diseases or subtypes in the Orphanet database. No language restriction is applied, and so far 10 languages are represented, with a predominance of CPGs in English, French and German (92% of all CPGs). A large proportion of diseases with identified CPGs belong to rare oncologic, neurologic, hematologic diseases or developmental anomalies. The Orphanet project on CPG collection, evaluation and dissemination is a continuous process, with regular addition of new guidelines, and updates. CPGs meeting the quality criteria are integrated to the Orphanet database of rare diseases, together with other types of textual information and the appropriate services for patients, researchers and healthcare professionals in 40 countries.