Insight into cross-talk between intra-amoebal pathogens

Abstract: Background: Amoebae are phagocytic protists where genetic exchanges might take place between amoeba-resistant bacteria. These amoebal pathogens are able to escape the phagocytic behaviour of their host. They belong to different bacterial phyla and often show a larger genome size than human-infecting pathogens. This characteristic is proposed to be the result of frequent gene exchanges with other bacteria that share a sympatric lifestyle and contrasts with the genome reduction observed among strict human pathogens.Results: We sequenced the genome of a new amoebal pathogen, Legionella drancourtii, and compared its gene content to that of a Chlamydia-related bacterium, Parachlamydia acanthamoebae. Phylogenetic reconstructions identified seven potential horizontal gene transfers (HGTs) between the two amoeba-resistant bacteria, including a complete operon of four genes that encodes an ABC-type transporter. These comparisons pinpointed potential cases of gene exchange between P. acanthamoebae and Legionella pneumophila, as well as gene exchanges between other members of the Legionellales and Chlamydiales orders. Moreover, nine cases represent possible HGTs between representatives from the Legionellales or Chlamydiales and members of the Rickettsiales order.Conclusions: This study identifies numerous gene exchanges between intracellular Legionellales and Chlamydiales bacteria, which could preferentially occur within common inclusions in their amoebal hosts. Therefore it contributes to improve our knowledge on the intra-amoebal gene properties associated to their specific lifestyle

La production du foie gras. Exemple d'un marché : Pau

The Production of, Foie Gras: the Market at Pau as an Example. The foie gras market at Pau is an interesting case because of its particular location as well as the nature and high price of the product concerned. It is difficult to consider it without referring directly to the product and studying the production techniques and' trading systems (such as sica, preserving firms and markets), in order to place the market at Pau in a wider context.Sa situation géographique, la nature des produits en jeu et leur prix élevé font du marché aux foies gras de Pau une entité bien spécifique. Il est vite apparu difficile de l'appréhender sans se référer directement au produit, en étudiant les techniques de production et les modes de commercialisation (tels que SICA, conserveries et marchés), afin de situer le marché de Pau comme élément d'un contexte global.Cazalet Catherine. La production du foie gras. Exemple d'un marché : Pau. In: Études rurales, n°78-80, 1980. Foires et marchés ruraux en France. pp. 277-288