Complex coevolutionary history of symbiotic Bacteroidales bacteria of various protists in the gut of termites

<p>Abstract</p> <p>Background</p> <p>The microbial community in the gut of termites is responsible for the efficient decomposition of recalcitrant lignocellulose. Prominent features of this community are its complexity and the associations of prokaryotes with the cells of cellulolytic flagellated protists. Bacteria in the order Bacteroidales are involved in associations with a wide variety of gut protist species as either intracellular endosymbionts or surface-attached ectosymbionts. In particular, ectosymbionts exhibit distinct morphological patterns of the associations. Therefore, these Bacteroidales symbionts provide an opportunity to investigate not only the coevolutionary relationships with the host protists and their morphological evolution but also how symbiotic associations between prokaryotes and eukaryotes occur and evolve within a complex symbiotic community.</p> <p>Results</p> <p>Molecular phylogeny of 31 taxa of Bacteroidales symbionts from 17 protist genera in 10 families was examined based on 16S rRNA gene sequences. Their localization, morphology, and specificity were also examined by fluorescent in situ hybridizations. Although a monophyletic grouping of the ectosymbionts occurred in three related protist families, the symbionts of different protist genera were usually dispersed among several phylogenetic clusters unique to termite-gut bacteria. Similar morphologies of the associations occurred in multiple lineages of the symbionts. Nevertheless, the symbionts of congeneric protist species were closely related to one another, and in most cases, each host species harbored a unique Bacteroidales species. The endosymbionts were distantly related to the ectosymbionts examined so far.</p> <p>Conclusion</p> <p>The coevolutionary history of gut protists and their associated Bacteroidales symbionts is complex. We suggest multiple independent acquisitions of the Bacteroidales symbionts by different protist genera from a pool of diverse bacteria in the gut community. In this sense, the gut could serve as a reservoir of diverse bacteria for associations with the protist cells. The similar morphologies are considered a result of evolutionary convergence. Despite the complicated evolutionary history, the host-symbiont relationships are mutually specific, suggesting their cospeciations at the protist genus level with only occasional replacements.</p

Effects of Preoperative Use of an Immune-Enhancing Diet on Postoperative Complications and Long-Term Outcome: A Randomized Clinical Trial in Colorectal Cancer Surgery in Japanese Patients

Background: Despite recent advances in surgical techniques and perioperative management, postoperative infectious complications remain a problem in surgical patients. We performed a prospective randomized clinical trial to examine the effects of preoperative Immune Enhancing Diets (IEDs) on postoperative complications in Japanese patients who underwent curative colorectal cancer surgery. This study was also designed to evaluate the optimal dose of preoperative IEDs for the patients without malnutrition. Finally, we analyzed recurrence free survival (RFS) and disease-specific survival (DSS) after surgery in patients who did and did not receive IEDspreoperatively.Material and Methods: This was a prospective, randomized clinical trial conducted at the Department of Surgery, National Defense Medical College, from October 2002 to October 2005. The 88 patients undergoing colorectal surgery were enrolled and were randomly divided into 3 groups. The high- (High, N=26) and low- (Low, N=31) dose groups received normal food and, respectively, 750ml/day or 250ml/ day of IEDs for 5 days before the operation. The primary endpoint was the rates of surgical site infection (SSI) and non- infectious complications. We also evaluated the RFS and DSS rate, respectively. Results: The patients were followed for 77±10 months (9-133 months) after surgery. Incisional SSI rates in the IEDs (High and Low) groups were significantly lower than in the Control group. (0%*, 0%* and 17%) (*P<0.01 vs. Control) The incidences of the infections not involving the surgical site (non-SSI) and the lengths of hospital stay were similar among the three groups. No significant differences were observed in RFS or DSS.Conclusion: In Japanese patients undergoing colorectal cancer surgery, preoperative IEDs significantly reduced the rate of incisional SSI as compared with the control group. Very interestingly, in Japanese patients, preoperative 250ml/day IED intake may be adequate for colorectal cancer patients without malnutrition. However, with regard to the long term outcome, beneficial effects of preoperative IEDs are not evident

The Lactic Acid Bacterium Pediococcus acidilactici Suppresses Autoimmune Encephalomyelitis by Inducing IL-10-Producing Regulatory T Cells

BACKGROUND: Certain intestinal microflora are thought to regulate the systemic immune response. Lactic acid bacteria are one of the most studied bacteria in terms of their beneficial effects on health and autoimmune diseases; one of which is Multiple sclerosis (MS) which affects the central nervous system. We investigated whether the lactic acid bacterium Pediococcus acidilactici, which comprises human commensal bacteria, has beneficial effects on experimental autoimmune encephalomyelitis (EAE), an animal model of MS. METHODOLOGY/PRINCIPAL FINDINGS: P. acidilactici R037 was orally administered to EAE mice to investigate the effects of R037. R037 treatment suppressed clinical EAE severity as prophylaxis and therapy. The antigen-specific production of inflammatory cytokines was inhibited in R037-treated mice. A significant increase in the number of CD4(+) Interleukin (IL)-10-producing cells was observed in the mesenteric lymph nodes (MLNs) and spleens isolated from R037-treated naive mice, while no increase was observed in the number of these cells in the lamina propria. Because only a slight increase in the CD4(+)Foxp3(+) cells was observed in MLNs, R037 may primarily induce Foxp3(-) IL10-producing T regulatory type 1 (Tr1) cells in MLNs, which contribute to the beneficial effect of R037 on EAE. CONCLUSIONS/SIGNIFICANCE: An orally administered single strain of P. acidilactici R037 ameliorates EAE by inducing IL10-producing Tr1 cells. Our findings indicate the therapeutic potential of the oral administration of R037 for treating multiple sclerosis

A Report on Overseas Teaching Practicum by Graduate Students in Elementary/Secondary Schools in the United States (IX)

This short paper reports on the 9th overseas teaching practicum in the United States by 12 graduate students of Hiroshima University, Japan, partly organized by Hiroshima University Global Partnership School Center (GPSC). The grand total has become 89 since this project started in 2006. The participants this year were those majoring in elementary/secondary school education, including one in-service teacher. They observed and conducted lessons in English in four local public schools in North Carolina. The aim of this project was threefold: 1) to self-develop practical instructional competence by teaching pupils with different cultural backgrounds; 2) to enhance the abilities in developing teaching materials through hands-on teaching experiences in English; and 3) to acquire the abilities to design, implement and evaluate programs for promoting global partnership. Like past years, their teachings were very positively covered by the local newspapers and websites. Later, the project was followed by cross-cultural field study visits to NC State Capitol, Raleigh and the U.S. Capitol, Washington, D.C. It is hoped that this intensive experience overseas will broaden the young future Japanese teachers’ global awareness and confidence in teaching

Bacillus subtilis variant natto Bacteremia of Gastrointestinal Origin, Japan

We report a case of bacteremia caused by Bacillus subtilis variant natto after a gastrointestinal perforation in a patient in Japan. Genotypic and phenotypic studies of biotin identified B. subtilis var. natto. This case and 3 others in Japan may have been caused by consuming natto (fermented soybeans)

The Motility Symbiont of the Termite Gut Flagellate Caduceia versatilis Is a Member of the “Synergistes” Group▿ †

The flagellate Caduceia versatilis in the gut of the termite Cryptotermes cavifrons reportedly propels itself not by its own flagella but solely by the flagella of ectosymbiotic bacteria. Previous microscopic observations have revealed that the motility symbionts are flagellated rods partially embedded in the host cell surface and that, together with a fusiform type of ectosymbiotic bacteria without flagella, they cover almost the entire surface. To identify these ectosymbionts, we conducted 16S rRNA clone analyses of bacteria physically associated with the Caduceia cells. Two phylotypes were found to predominate in the clone library and were phylogenetically affiliated with the “Synergistes” phylum and the order Bacteroidales in the Bacteroidetes phylum. Probes specifically targeting 16S rRNAs of the respective phylotypes were designed, and fluorescence in situ hybridization (FISH) was performed. As a result, the “Synergistes” phylotype was identified as the motility symbiont; the Bacteroidales phylotype was the fusiform ectobiont. The “Synergistes” phylotype was a member of a cluster comprising exclusively uncultured clones from the guts of various termite species. Interestingly, four other phylotypes in this cluster, including the one sharing 95% sequence identity with the motility symbiont, were identified as nonectosymbiotic, or free-living, gut bacteria by FISH. We thus suggest that the motility ectosymbiont has evolved from a free-living gut bacterium within this termite-specific cluster. Based on these molecular and previous morphological data, we here propose a novel genus and species, “Candidatus Tammella caduceiae,” for this unique motility ectosymbiont of Caducaia versatilis