, 1975), was performed to test for the presence of GlcNAc in WTA. Alexa Fluor 594® WGA was able to stain WT strain 10403S and DP-L5415,

but this lectin failed to bind to strains DP-L5359, DP-L5412, DP-L5413, and DP-L5414, pointing to a lack of GlcNAc residues in WTA (Fig. 4), which is restored in the DP-L5415 complemented with LMRG1707. The same results were obtained when binding assays were performed with GlcNAc-specific fluorescent P35 phage endolysin cell wall–binding domain HGFP-CBDP35 (Fig. 5). In this work, we have found that PTPs have an effect upon the Selleckchem Regorafenib composition of the Listeria cell wall. This is similar to many other bacteria including some pathogens (Grangeasse et al., 2007; Lacour et al., 2008; Bechet et al., 2009). In Gram-negative bacteria tyrosine kinases and phosphorylation were suggested to be involved in the production of emulsan in the nonpathogen Acinetobacter lwoffi (Nakar & Gutnick, 2003) and capsular polysaccharide production in E. coli and a few other bacteria (Obadia et al., 2007). In Gram-positive bacteria, a machinery that Vemurafenib includes tyrosine kinase and phosphatase was suggested

to be involved in the synthesis and export of extracellular polysaccharides, such as S. aureus (Soulat et al., 2002; Olivares-Illana et al., 2008) and S. pneumoniae (Morona et al., 2002). Similarly, protein tyrosine phosphorylation in L. monocytogenes is associated with changes in teichoic acid. However, no homologous machinery of the related Gram-positive S. pneumoniae or S. aureus can be found in L. monocytogenes. The change in teichoic acids of our four PTPs deletion mutant was the lack of N-acetyl glucosamine (GlcNAc) in the WTA. Liothyronine Sodium This was demonstrated by the changes in susceptibility to Listeria phages and could almost completely be restored

by functional LptpA2 and partially restored by LptpB1/lipA. The fact that phage A511 and the Ply of phage P35 bind GlcNAc in the WTA (Wendlinger et al., 1996; Eugster et al., 2011) confirms our observation. Because phage A118 adsorption is dependent on rhamnose decoration of WTA (Wendlinger et al., 1996), we did not observe any changes between the A118 binding comparing the WT and the DP-L5359 strain. The lack of GlcNAc in cell WTA was further confirmed by the lack of labeling with florescent WGA or HGFP-CBDP35. Protein tyrosine phosphatases in Listeria (e.g. the conventional PTPs LptpB1/LipA and LptpB2) were shown before to have dual function as tyrosine phosphatases and phosphoinositide phosphatases (Beresford et al., 2010; Kastner et al., 2011). No function was previously suggested for the low molecular weight LptpA1 and LptpA2. The PTP LptpB1/LipA was suggested to contribute to the virulence of two Listeria strains in a mouse infection model without obvious changes in macrophage or epithelial cells’ growth curve assays (Kastner et al., 2011).