Helicobacter suis KB1 derived from pig gastric lymphoid follicles induces the formation of gastric lymphoid follicles in mice through the activation of B cells and CD4 positive cells

"Helicobacter heilmannii" ("H. heilmannii"), which belongs to the genus Helicobacter, is a group of bacterial species that display a long spiral-shaped morphology. Recent studies have demonstrated that "H. heilmannii" type 1 is actually H. suis, which mainly colonizes the stomachs of various animals and humans. However, the influence of H. suis on gastric diseases remains to be fully elucidated. In this report, we revealed the relationship between natural H. suis infection and follicular gastritis in the pig stomachs. From sequence analysis of the 16S rRNA, urease A, and urease B genes, the presence of H. suis was confirmed in pig gastric lymphoid follicles, and this bacterium was named H. suis KB1. In addition, H. suis KB1 was inoculated into C57BL/6J mice, and the following mouse model of the pathogenesis of follicular gastritis by H. suis infection was established: H. suis KB1 colonizes the mouse stomach, and moreover, induces the development of lymphoid follicles and acquired immune responses characterized by the activation of B cells and CD4 positive cells. These results may lead to better understanding of the relationship between H. suis and gastric diseases, especially follicular gastritis; and furthermore, our findings emphasize the zoonotic aspects of animal-human infection by H. suis.     

Identification and isolation of active N2O reducers in rice paddy soil

Dissolved N₂O is occasionally detected in surface and ground water in rice paddy fields, whereas little or no N₂O is emitted to the atmosphere above these fields. This indicates the occurrence of N₂O reduction in rice paddy fields; however, identity of the N₂O reducers is largely unknown. In this study, we employed both culture-dependent and culture-independent approaches to identify N₂O reducers in rice paddy soil. In a soil microcosm, N₂O and succinate were added as the electron acceptor and donor, respectively, for N₂O reduction. For the stable isotope probing (SIP) experiment, ¹³C-labeled succinate was used to identify succinate-assimilating microbes under N₂O-reducing conditions. DNA was extracted 24 h after incubation, and heavy and light DNA fractions were separated by density gradient ultracentrifugation. Denaturing gradient gel electrophoresis and clone library analysis targeting the 16S rRNA and the N₂O reductase gene were performed. For culture-dependent analysis, the microbes that elongated under N₂O-reducing conditions in the presence of cell-division inhibitors were individually captured by a micromanipulator and transferred to a low-nutrient medium. The N₂O-reducing ability of these strains was examined by gas chromatography/mass spectrometry. Results of the SIP analysis suggested that Burkholderiales and Rhodospirillales bacteria dominated the population under N₂O-reducing conditions, in contrast to the control sample (soil incubated with only ¹³C-succinate). Results of the single-cell isolation technique also indicated that the majority of the N₂O-reducing strains belonged to the genera Herbaspirillum (Burkholderiales) and Azospirillum (Rhodospirillales). In addition, Herbaspirillum strains reduced N₂O faster than Azospirillum strains. These results suggest that Herbaspirillum spp. may have an important role in N₂O reduction in rice paddy soils.     

Accumulation of Secretory Vesicles in the Lacrimal Gland Epithelia Is Related to Non-Sjögren's Type Dry Eye in Visual Display Terminal Users

Previous observations in a rat model of a non-Sjögren''s syndrome (non-SS) type of dry eye seen in users of visual display terminals (VDT) indicated that secretory vesicle (SV) accumulation in the lacrimal gland epithelia contributes to the condition. Here, to examine this possibility in humans, we compared the lacrimal gland histology and percent SV area in the cytoplasm of acinar epithelial cells using light microscopy and transmission electron microscopy, in patients with VDT work-related non-SS dry-eye (VDT group), SS-induced dry-eye, and autopsied normal controls. In addition, the VAMP8 (vesicle-associated membrane protein 8, an exocrine-pathway molecule) and Rab3D (mature vesicle marker) were histochemically examined in lacrimal gland tissue sections. The lacrimal gland acini were larger in the VDT group than in the SS group, and the percent SV area was significantly higher in the VDT group than in the normal controls (P = 0.021) or SS group (P = 0.004). Immunostaining revealed abnormal distributions of VAMP8 in the VDT and SS groups. Rab3D was more strongly expressed in the cytoplasm of acinar epithelial cells in the VDT group than in that of normal controls. The duration of VDT use was significantly longer in the VDT group than in the other groups. These findings suggest that excessive SV accumulation in the acinar epithelia may contribute to the reduced tear secretion in VDT users.     

Molecular cloning, functional expression, and characterization of isolectin genes of hemolytic lectin CEL-III from the marine invertebrate Cucumaria echinata

CEL-III is a hemolytic lectin purified from the marine invertebrate Cucumaria echinata. Previous research has indictated that CEL-III is composed of several isoforms. Here we identified five CEL-III isolectin genes, designated CEL-III-L1, CEL-III-L2, CEL-III-S1, CEL-III-S2, and CEL-III-LS1, by cDNA cloning. The deduced amino acid sequences suggested they shared 94.0-99.8% identical residues. Among the amino acid residues involved in carbohydrate binding, the His residue, which contributes to stacking with sugar, in subdomain 1α was replaced by Tyr in CEL-III-L2. The recombinant proteins were expressed in Escherichia coli or insect cells. rCEL-III-L2 showed higher hemolytic activity than those of the other isolectins. Furthermore, an apparent oligomer band of rCEL-III-L2 was detected on erythrocyte membranes, although the other isolectins showed smear bands. These results suggest that Tyr36 of CEL-III-L2 is important for the expression of hemolytic activity and oligomerization.     

A rodent malaria, Plasmodium berghei, is experimentally transmitted to mice by merely probing of infective mosquito, Anopheles stephensi

We found that infection of a rodent malaria, Plasmodium berghei, occurred when the sporozoites were injected into the skin, the muscle, the peritoneal cavity and the tail end. Mice, which were injected with sporozoites in the tail end and had the site cut 5 min later, did not develop malaria. We also found that mice developed malaria when malaria infective mosquitoes, Anopheles stephensi, were forced not to take blood but only to probe into the skin. Moreover, the mice probed by the infective mosquitoes were protected from malaria infection if the site was treated with Kyu (heat treatment) after the mosquitoes had probed. These findings indicate that malaria infection occurs not only by blood feeding of the infective mosquito but also by probing of the mosquito. Sporozoites injected into the skin remain at the injected site for at least 5 min, then migrate to the blood vessels and invade into the blood stream. At present, the mechanism is not clear, although we propose here the existence of the skin stage of malaria parasites before the liver stage and the blood stage.     

The Semaphorin 3A Inhibitor SM-345431 Accelerates Peripheral Nerve Regeneration and Sensitivity in a Murine Corneal Transplantation Model

Background

Peripheral nerve damage of the cornea is a complication following surgery or infection which may lead to decreased visual function. We examined the efficacy of the semaphorin 3A inhibitor, SM-345431, in promoting regeneration of peripheral nerves in a mouse corneal transplantation model.

Methodology/Principal Findings

P0-Cre/Floxed-EGFP mice which express EGFP in peripheral nerves cells were used as recipients of corneal transplantation with syngeneic wild-type mouse cornea donors. SM-345431 was administered subconjunctivally every 2 days while control mice received vehicle only. Mice were followed for 3 weeks and the length of regenerating nerves was measured by EGFP fluorescence and immunohistochemistry against βIII tubulin. Cornea sensitivity was also measured by the Cochet-Bonnet esthesiometer. CD31 staining was used to determine corneal neovascularization as a possible side effect of SM-345431. Regeneration of βIII tubulin positive peripheral nerves was significantly higher in SM-345431 treated mice compared to control. Furthermore, corneal sensitivity significantly improved in the SM-345431 group by 3 weeks after transplantation. Neovascularization was limited to the peripheral cornea with no difference between SM-345431 group and control.

Conclusions/Significance

Subconjunctival injections of SM-345431 promoted a robust network of regenerating nerves as well as functional recovery of corneal sensation in a mouse keratoplasty model, suggesting a novel therapeutic strategy for treating neurotrophic corneal disease.     

Whole-embryo culture of E5.5 mouse embryos: development to the gastrulation stage

This study reports establishment of an in vitro culture system for E5.5 mouse embryos that supports development to the gastrulation stage and allows the use of experimental approaches to study gastrulation during mouse embryogenesis. Recent experiments suggest that the extraembryonic tissues may play a critical role for gastrulation from as early as E5.5. To apply whole embryo culture to E5.5 embryos and analyze gastrulation, it is essential to optimize the conditions so that most of the embryos develop to the gastrulation stage in culture. For this purpose, we established a protocol in which embryos were isolated using micromanipulator and cultured with 50-75% rat serum. Although cultured embryos tended to grow a larger extraembryonic portion, more than 80% of them developed the primitive streak and induce mesoderm, which corresponds to the mid-streak stage.