Infectious diseases and breeding conditions can influence fish health status. Furthermore it is well known that human and animal health are strongly correlated. In lower vertebrates melano-macrophage centres, clusters of pigment-containing cells forming the extracutaneous pigment system, are widespread in the stroma of the haemopoietic tissue, mainly in kidney and spleen. In fishes, melanomacrophage centres play an important role in the immune response against antigenic stimulants and pathogens. Hence, they are employed as biomarker of fish health status. We have investigated this cell system in the European sea bass (Dicentrarchus labrax L.) following the enzyme activities involved in melanin biosynthesis. We have found a possible relationship between kidney disease of farmed fishes and dopa oxidase activity level, suggesting it as an indicator of kidney disease. Moreover variations of dopa oxidase activity in extracutaneous pigment system have been observed with respect to environmental temperature. At last, for the first time, using femtosecond transient absorption spectroscopy (Femto-TA), we pointed out that pigment-containing cells of fish kidney tissue present melanin pigments.

We have investigated a potential link between small heat shock proteins (sHsps) and membranes in Lactobacillus plantarum WCFS1. The sHsp family is the best characterized protein subset among the L. plantarum Hsps, and it represents the principal heat shock regulon of Gram-positive bacteria in this bacterium. Exposure to benzylic alcohol (BA) (60 mM) alone was found to cause membrane fluidization in the absence of any other stress and to induce transcription of the heat shock genes (shs) to the same extent as a lethal heat shock. Using a fluorescence anisotropy-based method, we detected a reduction in the maximal fluidification level in two L. plantarum strains that singly over-produce Hsp18.5 and Hsp19.3. Overall, these results indicate that, under the stress conditions analysed, these two members of the sHsps family of L. plantarum WCFS1 have a membraneactivating effect. The findings also form a basis for proposing membrane fluidity as a new target for prestress treatments to enhance probiotic, food starter and bioproduction applications of L. plantarum.

A potential link between small heat shock proteins (sHsps) and membranes in Lactobacillus plantarum WCFS1, was investigated. The sHsps family is the best characterized protein subset among of L. plantarum Hsps, and it represents the principal heat shock regulon of Gram positive bacteria recognized in this bacterium. We found that the exposure to benzylic alcohol (60 mM), that causes only a membrane fluidization without any other stress, can induce transcription of the shs genes to the same extent as a lethal heat shock. Using a fluorescence anisotropy-based method, we detected a reduction of the maximal fluidification level in two L. plantarum strains that singly over-produce Hsp18.5 and Hsp19.3. Overall, these results indicate, under the stress conditions analysed, a membrane-activity effect of two members of sHsps family of L. plantarum WCFS1. Furthermore, these evidences represent the basis to propose membrane fluidity as a new target for pre-stress treatments to enhance probiotic, food starter, and bioproduction applications of L. plantarum.

Lactic acid bacteria (LAB) are a group of microorganisms generally associated to food industry as they are traditionally applied in the production of several fermented food. Beside the aim to optimize the quality of the end product determining the organoleptic and nutritional profile, LAB can also contribute to the safety assessment of food producing different compounds with antimicrobial activity such as bacteriocins, antimicrobial peptides and low molecular weight compounds. The production of antimicrobial compounds could be considered a suitable trait to be sought in the selection of starter, non-starter and probiotic strains due to the realistic use of these bacteria in the food industry in order to reduce spoilage and pathogenic microorganisms, increase the shelf life, moderate or eliminate the chemical additives. Moreover, the antagonistic activity can also aim to contrast the alarming problem of antibiotic resistance that is a crucial safety pre-assessment. Here, the potential use of LAB as biopreservatives and biotherapeutic agents in the food industry, and an overview about their resistance to antibiotics are discussed.

FAO and WHO guidelines define as 'probiotics' those 'microorganisms which confer a health benefit to the host. Most of the currently used probiotics belong to the genera of Lactobacillus and Bifidobacterium. Lactobacillus plantarum (Lp) is a lactic acid bacterium (LAB) which grows on various substrates, including animal and vegetable foods (either as autochthonous contamination or being added as starter culture), soil and mammalian intestine. We have generated Lp WCFS1 mutant strains which are defective for different stress response genes. Preliminary works suggest that some of these strains might present distinctive cell surface physico-chemical and morphological features. Because bacterial cell envelope is primarily implicated in cell-host interaction, with the aim to evaluate their potential probiotic properties, we have compared the effects of wild type and mutant L. plantarum cells on the expression pattern of some immune-related genes in human intestinal epithelial cells. Caco-2 monolayers were incubated with bacterial cells at defined titre; transcriptional profiling of human immune genes was assessed by real time quantitative RT-PCR.

Dietary probiotics should reach the intestine viable and in high numbers; therefore, they should tolerate the stress associated to the gastro-intestinal (GI) environment. Indeed, all along the different GI sections, probiotics are challenged by several sources of stress, including low pH, bile and digestive enzymes. Bacterial cells are equipped with various defense mechanisms to allow survival in hostile environments. The food matrix used to deliver beneficial bacteria may contribute to their probiotic action, e.g. by enhancing survival to stress and gut colonization. In this study, the survival of the lactic acid bacterium Lactobacillus plantarum WCFS1, a model probiotic strain, was examined in a human oro-gastric-intestinal (OGI) in vitro system, using different carrier matrices to compare protective and buffering properties. Higher survival was observed in complex and/or nutrient-rich matrices, and when potential prebiotics were added. The molecular response of L. plantarum to the OGI transit was analysed by studying the transcriptional levels of genes involved in stress response and probiosis. The OGI steps of higher mortality corresponded to greater induction of stress genes, thus implying their involvement in adaptation to the gut environment. Plantaricins were significantly upregulated all along the different OGI sections; adhesion genes were mainly induced by gastric environment.

Melanogenesis is mostly studied in melanocytes and melanoma cells, but much less is known about other pigment cell systems. Liver, spleen, kidney, and other organs of lower vertebrates harbour a visceral pigment cell system with an embryonic origin that differs from that of melanocytes. In teleosts, melanin-containing cells occur in the reticulo-endothelial system and are mainly in the kidney and spleen. The Atlantic salmon (Salmo salar L.) is an ichthyic breeding species of considerable economic importance. The accumulation of pigments in salmon visceral organs and musculature adversely affects the quality of fish products and is a problem for the aquaculture industry. With the aim to reveal novel functions and behaviour of the salmonid extracutaneous pigment system, we investigated aspects of the melanogenic systems in the tissues of Atlantic salmon, as well as in SHK-1 cells, which is a long-term cell line derived from macrophages of the Atlantic salmon head-kidney. We demonstrate that a melanogenic system is present in SHK-1 cells, head-kidney, and spleen tissues. As teleosts lack lymph nodes and Peyer’s patches, the head-kidney and spleen are regarded as the most important secondary lymphoid organs. The detection of tyrosinase activity in lymphoid organs indicates that a link exists between the extracutaneous pigmentary system and the immune system in salmon

The scientific-social-economic importance of traditional fermented foods is widely testified by the worldwide importance of 'geographical indication (GI)' (WIPO, World Intellectual Property Organization; WTO, World Trade Organization). Belonging to the intellectual property law, the 'geographical indication is a sign used on goods that have a specific geographical origin and possess qualities, reputation or characteristics that are essentially attributable to that place of origin' (WIPO, World Intellectual Property Organization). Plant varieties, local animal breeds, and traditional knowledge are recognized to be geographical attributes. It is widely recognized that the emergence of a given microbiota in a food matrix uniquely influences the global quality of final product. We study autochthon microbial ecology of GI food fermentations and we characterize a representative number of microbial isolate with a particular attention to lactic acid bacteria. Thus, we selected a panel of microbial strains representing the 'virtuous' microbial biodiversity of a specific terroir and for a given GI food production. Starting from this list, GI fermented food producers might formulate their own multi-strains starter culture. Our core business covers also starter cultures production. The principal implication of our perspective is the improvement of GIs 'unique qualities' via an enhanced management of microbial biodiversity in food environments, naturally maintaining a high attention to biological risks for human health and industrial exigencies of product standardization. In general, turning in technological transfer, this interdisciplinary innovation leads to development opportunities for local research teams in microbial ecology and food microbiology, academic spin-off companies, bioentrepreneurs, and microbial collections.

Milk, a basic component of the human diet, is rich in all kinds of nutrients, such as proteins, carbohydrates, lipids, vitamins, and minerals. These compounds comprise an ideal growth substrate for both harmful and beneficial microorganisms, making milk a perishable raw material. As a result, milk contains numerous microorganisms that originate either from the animal itself, even when the animal is clinically healthy, or from the environment during the collection and storage of milk. The increasing social, economic, and research on non-cow types of milk and its products illustrates the renewed interest in the microbiota associated with these matrices. The present work is an overview of existing knowledge on the microbiota of sheep, goat, buffalo, camel, equine, yak, and human milk and their products. Relevant studies concerning both classical microbiological approaches as well as advanced molecular methods are included.