The DNA-binding site of HutR located in front of the hutR gene is very close to the −35 promoter region (Fig. 4b), presumably indicating a mode of autorepression. In Gram-negative bacteria, the expression of histidine catabolic enzymes is controlled by both specific repression mediated by a local regulator interacting with histidine or urocanate and general induction mediated by global regulatory proteins that sense the physiological signals of the cell, for instance cAMP (Nieuwkoop et al., 1984). The global activators of hut gene expression can differ depending upon whether histidine is a source of carbon or nitrogen

(Janes et al., 2003). The corresponding global control in C. resistens might be assumed by the corynebacterial cAMP-sensing regulator GlxR (Kohl & Tauch, 2009; Schröder & Tauch, 2010), probably interacting with predicted DNA-binding sites Everolimus concentration selleck products in front of hutHUI and hutG (Fig. 4a and b). “
“SalmonellaDakar and SalmonellaTelaviv bacteria belong to serogroup O:28, which represents 107 serovars and possesses only the epitope O28. SalmonellaTelaviv has the subfactors O281 and O282, whereas S. Dakar has O281 and O283. So far, only limited serological and immunological information for this serogroup is available in the literature. Knowledge of the structures of their O-polysaccharides

and the immunochemical investigations performed in this work allowed to reveal the nature of subfactor O281 as attributed to the presence of 3-linked (or 3,4-disubstituted) α-d-GalpNAc in the main chains

of S. Dakar and S. Telaviv O-polysaccharides. An explanation for the cross-reactions between Salmonella entericaO28 O-antigens and other SalmonellaO-polysaccharides and their structural similarity to Escherichia coliO-serogroups is also given. The genus Salmonella contains over 2570 serotypes (Grimont & Weill, Celecoxib 2007), all potentially pathogenic to humans (Tauxe & Pavia, 1998). Specifically, Salmonella enterica subsp. enterica figures predominantly as one of the leading causes of bacterial food-borne disease as a result of the contamination of food products (Finlay & Falkow, 1989; D’Aoust, 1994; Swaminathan et al., 2006). The Salmonella serotyping is based on serological methods (Lüderitz et al., 1966; Lindberg & Le Minor, 1984). One of the major antigens of the Salmonella spp. is O-somatic antigen (O-antigen; the O-polysaccharide, OPS), which together with the core region builds up the saccharide fragment of the lipopolysaccharide (LPS) (Caroff & Karibian, 2003). O-antigenic determinants are expressed only in smooth-type Gram-negative bacteria. O-Antigens are extremely variable, and the variation is caused by the nature, order, conformation and the linkage of the different sugar residues within the polysaccharide chain (Samuel & Reeves, 2003).