Draft genome sequence of the Aeromonas diversa type strain

We present here the first genome sequence of the Aeromonas diversa type strain (CECT 4254T). This strain was isolated from the leg wound of a patient in New Orleans (Louisiana, USA) and was originally described as Enteric Group 501 and distinguished from A. schubertii by DNADNA hybridization and phenotypical characterization.

Bicelles: new nano systems for skin applications

Bicellar systems are lipid nanostructures formed by long- and short-chained phospholipids dispersed in aqueoussolution. Because of their attractive combination of lipid composition, small size and morphological versatility, bicellesbecame new targets for skin research. Bicelles modify the skin biophysical parameters and modulate the skin barrier function acting as enhancers for drug penetration. Moreover, these aggregates have the ability to penetrate through the narrowintercellular spaces of the skin stratum corneum and to reinforce its lipid lamellae. Their structures allows for the incorporation of different molecules that can be carried through the skin layers. Theremarkable versatility of bicelles is their most important characteristic, which makes it possible their use in different fields.These aggregates represent new nanosystems for skin applications. In this work we provide an overview of the main properties ofbicelles and their effects on the skin.

Loss of intestinal epithelial barrier function in Salmonella Enteritidis infection

Intestinal infection with Salmonella enterica serotype Enteritidis, a food-borne infection spread to humans especially through contaminated eggs and egg-products as well as undercooked contaminated fresh meat, is the most common cause of intestinal inflammation in the European Union. Enteritis caused by Salmonella Enteritidis is characterized by fever, diarrhoea and abdominal pain. The disruption of the intestinal epithelial barrier function contributes to diarrhoea and is responsible for the perpetuation of the inflammatory process. In this sense, oxidative stress and the proinflammatory cytokines TNF-α, IFN-γ and IL-1β are described to induce the disorganization of the tight junctions (TJ), the most apical epithelial intercellular junctions and responsible for the paracellular permeability. The interest of this chapter relies not only in the investigation dealing with the mechanisms of TJ regulation but also in the contribution to the development of new tools for the prevention of epithelial barrier disruption in enteritis caused by Salmonella Enteritidis.

Membrane interaction of a new synthetic antimicrobial lipopetide sp-85 with broad spectrum activity

Antimicrobial peptides offer a new class of therapeutic agents to which bacteria may not be able todevelop genetic resistance, since their main activity is in the lipid component of the bacterial cell mem-brane. We have developed a series of synthetic cationic cyclic lipopeptides based on natural polymyxin,and in this work we explore the interaction of sp-85, an analog that contains a C12 fatty acid at theN-terminus and two residues of arginine. This analog has been selected from its broad spectrum antibac-terial activity in the micromolar range, and it has a disruptive action on the cytoplasmic membrane ofbacteria, as demonstrated by TEM. In order to obtain information on the interaction of this analog withmembrane lipids, we have obtained thermodynamic parameters from mixed monolayers prepared withPOPG and POPE/POPG (molar ratio 6:4), as models of Gram positive and Gram negative bacteria, respec-tively. LangmuirBlodgett films have been extracted on glass plates and observed by confocal microscopy,and images are consistent with a strong destabilizing effect on the membrane organization induced bysp-85. The effect of sp-85 on the membrane is confirmed with unilamelar lipid vesicles of the same com-position, where biophysical experiments based on fluorescence are indicative of membrane fusion andpermeabilization starting at very low concentrations of peptide and only if anionic lipids are present.Overall, results described here provide strong evidence that the mode of action of sp-85 is the alterationof the bacterial membrane permeability barrier.