The foodborne bacterial pathogen, Campylobacter jejuni, possesses an N-linked protein glycosylation (pgl) pathway involved in adding conserved heptasaccharides to asparagine-containing motifs of >60 proteins, and releasing the same glycan into its periplasm as free oligosaccharides. In this study, comparative genomics of all 30 fully sequenced Campylobacter taxa revealed conserved pgl gene clusters in all but one species. Structural, phylogenetic and immunological studies showed that the N-glycosylation systems can be divided into two major groups. Group I includes all thermotolerant taxa, capable of growth at the higher body temperatures of birds, and produce the C. jejuni-like glycans. Within group I, the niche-adapted C. lari subgroup contain the smallest genomes among the epsilonproteobacteria, and are unable to glucosylate their pgl pathway glycans potentially reminiscent of the glucosyltransferase regression observed in the O-glycosylation system of Neisseria species. The nonthermotolerant Campylobacters, which inhabit a variety of hosts and niches, comprise group II and produce an unexpected diversity of N-glycan structures varying in length and composition. This includes the human gut commensal, C. hominis, which produces at least four different N-glycan structures, akin to the surface carbohydrate diversity observed in the well-studied commensal, Bacteroides. Both group I and II glycans are immunogenic and cell surface exposed, making these structures attractive targets for vaccine design and diagnostics. Molecular & Cellular Proteomics 11: 10.1074/mcp.M112.021519, 1203-1219, 2012.In eukaryotes, glycosylated proteins are ubiquitous components of extracellular matrices and cellular surfaces. Their oligosaccharide moieties are implicated in a wide variety of essential cell-cell and cell-matrix processes ranging from immune recognition to cancer development. The first general protein glycosylation (pgl) 1 pathway was discovered in the epsilonproteobacterium Campylobacter jejuni (1). The organism transfers a conserved heptasaccharide en bloc to asparagine residues within the sequon D/E-X 1 -N-X 2 -S/T (X 1 , X 2 P) of Ͼ60 glycoproteins (2-4). Furthermore, the pathway can be functionally transferred into Escherichia coli, and the oligosaccharyltransferase (OTase), PglB, is capable of adding foreign sugars to acceptor proteins (5-7). C. jejuni PglB also possesses hydrolase activity, influenced by the cellular growth phase and osmotic environment, releasing free oligosaccharides (fOS) into the periplasmic space in a 10:1 ratio relative to the amount of heptasaccharide N-linked to protein (8, 9).The C. jejuni N-linked heptasaccharide is conserved in structure in both C. jejuni and C. coli, the two most commonly isolated pathogenic Campylobacter species and major causes of human enteritis worldwide (10, 11). All campylobacters, but one, possess conserved pgl genes required for Nlinked protein glycosylation ((12) and this study). This posttranslational modification in C. jejuni influences DNA uptake, chicken and ...

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In the brain, the serotonergic neurons located in the raphe nucleus are the unique resource of the neurotransmitter serotonin, which plays a pivotal role in the regulation of brain development and functions. Dysfunction of the serotonin system is present in many psychiatric disorders. Lack of in vitro functional human model limits the understanding of human central serotonergic system and its related diseases and clinical applications. Previously, we have developed a method generating human serotonergic neurons from induced pluripotent stem cells (iPSCs). In this study, we analyzed the features of these human iPSCs-derived serotonergic neurons both in vitro and in vivo. We found that these human serotonergic neurons are sensitive to the selective neurotoxin 5, 7-Dihydroxytryptamine (5,7-DHT) in vitro. After being transplanted into newborn mice, the cells not only expressed their typical molecular markers, but also showed the migration and projection to the host’s cerebellum, hindbrain and spinal cord. The data demonstrate that these human iPSCs-derived neurons exhibit the typical features as the serotonergic neurons in the brain, which provides a solid foundation for studying on human serotonin system and its related disorders.

Footprint-preserving knotless single-row repair obtains similar clinical results compared to tear completion repair in the treatment of articular-sided PTRCTs. Footprint-preserving knotless single-row repair may be a convenient choice for the treatment of articular-sided PTRCTs. Randomized controlled studies are needed to investigate whether the footprint-preserving knotless single-row repair yields better long-term outcomes through the protection of the bursal cuff and restoration of the healthy footprint.

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Cardiolipin (CL) is an anionic tetraacylphospholipid found in mammalian tissues, inner membrane of mitochondria and in the cytoplasmic membrane of Gram-positive and -negative bacteria. Lipid A is the principal structural component responsible for the range of biological activities of lipopolysaccharides. Here we report a MALDI-MS-based method for the sensitive simultaneous analysis of CL and lipid A from Helicobacter pylori cells. The sensitivity was demonstrated by the analysis of CL and lipid A from a single bacterial colony of in vitro grown H. pylori strain NCTC 11637 (ATCC 43504). We then characterized the CL and lipid A structures in H. pylori cells grown under three different conditions, on agar-horse blood plates, in liquid culture and ex vivo. The results revealed the presence of high amounts of myristic (C14:0) and 19-carbon cyclopropane (C19:0cyc) fatty acids. Alterations in CL structure were observed in H. pylori cells cultivated on plates as compared with the bacteria grown in broth culture. Furthermore, significant changes in lipid A acylation pattern were detected in H. pylori cells during formation of coccoids. In contrast, structural analysis of CL from ex vivo H. pylori cells recovered from the stomachs of infected Mongolian gerbils demonstrated only minor changes in acyl chain combination. This is the first report of simultaneous analysis of CL and lipid A from ex vivo cells of H. pylori.

Research has indicated that stress on the endoplasmic reticulum (ER) of a cell affects the pathogenesis of metabolic disorders such as obesity, type 2 diabetes mellitus, and non‐alcoholic fatty liver disease (NAFLD). Palmitate, a saturated fatty acid, is known to induce toxicity and cell death in various types of cells. Tanshinone IIA (Tan IIA), one of the effective components of the traditional Chinese medicine Danshen, was reported to exhibit a variety of biochemical activities, including amelioration of ER stress‐mediated apoptosis in renal preservation. To address the hypothesis that tan IIA attenuates apoptosis and triglycerides (TG) accumulation via reducing ER stress, we studied the effect of tan IIA on experimentally induced ER stress using palmitate in HepG2 cells. Palmitate led to cytotoxicity, TG accumulation, and apoptosis in HepG2 cells and also strongly induced ER stress indicated by increased GRP78, phosphorylation of eIF2α, ATF6, and CHOP. Pretreatment with tan IIA (10 μm) significantly increased cell viability, decreased apoptotic cell death, and reduced the activity of caspase‐3. Meanwhile, tan IIA significantly decreased palmitate‐induced TG accumulation. Moreover, tan IIA significantly suppressed the phosphorylation of eIF2α, and inhibited GRP78, ATF6, and CHOP expression. In conclusion, tan IIA protects the HepG2 cells exposed to palmitate partially by inhibiting excessive ER stress, ER stress‐induced apoptosis, and hepatic steatosis. Therefore, tan IIA has therapeutic potential in the treatment of NAFLD.