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4500

AbstractBackground:  “Candidatus Helicobacter heilmannii” induce chronic gastritis, which eventually leads to gastric B‐cell type mucosa‐associated lymphoid tissue (MALT) lymphoma. This study was performed using an animal model of infection with “Candidatus Helicobacter heilmannii” to elucidate how this chronic inflammation is induced or maintained.Materials and Methods:  BALB/c mice were infected with the “Candidatus Helicobacter heilmannii” isolate SH4. The animals were examined at 8, 26, 54, and 83 weeks after the infection. The stomach of the animals was resected and immunostained for peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM‐1), “Candidatus Helicobacter heilmannii,” and CD45R/B220. An in vitro binding assay with L‐ and E‐selectin·IgM chimeric proteins was performed. Real‐time polymerase chain reaction was used to evaluate transcripts of N‐acetylglucosamine‐6‐O‐sulfotransferases (GlcNAc6STs), which direct the expression of the PNAd and MAdCAM‐1.Results:  Chronic gastritis developed in the infected animals, and its severity increased with the duration of the infection. B‐cell type MALT lymphoma developed in some animals at 54 and 83 weeks after infection. PNAd‐ and MAdCAM‐1‐expressing high endothelial venule (HEV)‐like vessels were induced in infected animals which developed chronic gastritis and MALT lymphoma. The number of HEV‐like vessels increased as chronic inflammation progressed. The induced HEV‐like vessels were bound by L‐ and E‐selectin·IgM chimeric protein. mRNA expressions of GlcNAc6ST‐1 and MAdCAM‐1 increased in the infected animals.Conclusions:  HEV‐like vessels expressing GlcNAc6ST‐1‐mediated L‐selectin ligand carbohydrate and MAdCAM‐1 may play a crucial role in the pathogenesis of “Candidatus Helicobacter heilmannii”‐induced chronic gastritis and MALT lymphoma.

A novel aerobic, heterotrophic bacterium, designated BiosLi39T, was isolated from the South East Pacific Ocean. Cells were Gram-negative gliding rods forming yellow colonies on marine agar. The isolate was oxidase-, catalase- and alkaline phosphatase-positive andβ-galactosidase-negative. Strain BiosLi39Tgrew at 20-37 °C (optimum 30 °C), at pH 7.0–9.0 (optimum pH 8.0) and with 20–60 g NaCl l−1(optimum 30–50 g NaCl l−1). The fatty acids (>1 %) comprised iso-C14 : 0, iso-C15 : 1G, iso-C15 : 0, anteiso-C15 : 0, C15 : 1G, C15 : 0, iso-C15 : 02-OH, iso-C16 : 1G, iso-C16 : 0, iso-C16 : 03-OH, iso-C16 : 02-OH, iso-C17 : 03-OH, C17 : 02-OH and three unidentified components with equivalent chain lengths of 17.87, 18.10 and 18.71. A significant proportion of the hydroxylated fatty acids are amide-linked. The lipid pattern indicated the presence of phosphatidylethanolamine, two unidentified aminolipids and three unidentified polar lipids. The strain contained menaquinone 7 as the sole respiratory lipoquinone and did not produce flexirubin-type pigments. The G+C content of the genomic DNA was 37.2 mol%. Comparative 16S rRNA gene sequence analysis indicated that strain BiosLi39Twas distantly related to all of the representatives of the phylumBacteroidetes. Its closest relative wasMarinoscillum furvescensIFO 15994T, with which it shared 92.5 % 16S rRNA gene sequence similarity. On the basis of genotypic, phenotypic and chemotaxonomic characteristics, we propose a novel genus and species,Ekhidnagen. nov., sp. nov., with type strain BiosLi39T(=DSM 19307T=CIP 109600T=OOB 398T).