Final reaction conditions were 7 mM DMB, 18 mM sodium hydrosulfite, 1.4 M acetic acid, and 0.7 M 2-mercaptoethanol. Derivatization was carried out for 2 hours at 50°C in the dark. High performance liquid chromatography and mass spectrometry DMB-NulO derivatives PLX-4720 cost were resolved by HPLC using a reverse phase C18 column (Varian) eluted isocratically at a rate of 0.9 ml/min

over 50 minutes using 85 % MQ-water, 7 % methanol, 8 % acetonitrile as previously described [16, 39, 40]. In some experiments, HPLC was performed without online mass spectrometry and detection of fluorescently labeled NulO sugars was achieved using an online fluorescence detection using excitation and emission wavelengths of 373 nm and 448 nm www.selleckchem.com/products/Everolimus(RAD001).html respectively. In other experiments HPLC was combined with online mass spectrometry using a Thermo-Finnigan model LCQ ion trap mass spectrometer system. When mass spectrometry was performed, the buy GKT137831 mobile phase also included 0.1 %

formic acid, and online UV detection of DMB-NulO molecules preceded mass spectrometric analysis. We note that similar HPLC-MS analyses have been described previously DMB-derivatized α-keto acids [39–41]. Phylogenetic analysis We performed BLAST searches (blastp) against the NCBI genome database using as seeds the sequences of 1) proteins encoded by Campylobacter jejuni pseudaminic, legionaminic, and neuraminic acid biosynthetic pathways

or 2) enzymes encoded in the Leptospira interrogans NulO biosynthetic gene cluster (Figure 1A). NCBI accession numbers are provided in Table 1 and a schematic of the biosynthetic pathways is illustrated in Figure 5. Complete protein sequences of homologous amino acids were aligned using ClustalW Unoprostone in MacVector 11.1.1 software and alignments were checked manually. The Neighbor Joining (NJ) method was utilized for phylogenetic tree construction using MacVector 11.1.1 software, including 1000 Bootstrap replications to obtain confidence values for branches of the NJ trees. Solid-phase lectin binding Whole cell lysates were prepared using three cycles of freeze-thawing of PBS washed L. interrogans serovar Copenhageni strain L1-130. In order to probe the abundance and nature of the sialylated molecules on L. interrogans, these lysates were fractionated using a lectin-based solid phase assay (Q Proteome Sialic Acid kit, Qiagen) using three immobilized sialic acid binding lectins: wheat germ agglutinin (WGA), Sambucus nigra agglutinin (SNA), and Maackia amurensis lectin (MAL), according to manufacturer’s instructions. Molecules captured by each of these lectins were eluted according to the manufacturers instructions. then analyzed by SDS-PAGE followed by silver staining (SilverQuest Silver Staining Kit, Invitrogen). Mass spectrometry To determine whether L.