Takahashi O.,Hiroshima University |
Kohno Y.,Yokohama National University |
Nishio M.,CHPI Institute
Chemical Reviews | Year: 2010
Researchers conducted investigations to reveal evidence from the latest experimental data and high-level ab initio MO calculations regarding the relevance of weak hydrogen bonds in the conformation of organic compounds and bioconjugates. The researchers showed that the gauche or folded conformation prevailed in organic compounds bearing at least an electronegative or π-group in the molecule. Evidence gathered from the investigations revealed that the gauche or folded conformation is preferred to describe the relevance of weak hydrogen bonds in the conformation of organic compounds and bioconjugates. It was demonstrated that weak attractive forces were essential in deciding the conformation of organic compounds and the 3D structure of biomacromolecules. Researchers also gathered evidence that revealed that hydrogen bonds other than the conventional hydrogen bond were ubiquitous.
Abe M.,Hiroshima University |
Abe M.,Japan Institute for Molecular Science |
Abe M.,Japan Science and Technology Agency
Chemical Reviews | Year: 2013
Recent development in diradical chemistry are summarized in detail. Diradicals are long-known chemical species, but they continue to be fascinating molecules because of their inherently high reactivity and their potential molecular functions, which are mainly derived from their small HOMO-LUMO energy gaps. Kinetic stabilization and thermodynamic stabilization have made it possible to isolate diradical species. The terminology of singlet and triplet states in diradicals is derived from the number of energy level in diradicals under an external magnetic field. The triplet state is the ground-state spin multiplicity for diradicals in which a large overlap integral exists between the two energetically degenerate molecular orbitals that are occupied by two electrons. Localized diradicals are key intermediates in processes involving the homolytic bond-cleavage and -formation reactions of cyclic compounds.
Tanabe S.,Hiroshima University
International Reviews of Immunology | Year: 2013
Probiotics and gut microbiota have a significant impact on gut homeostasis in the host. Recent clinical studies demonstrated the ameliorative features of several kinds of probiotics in intestinal disorders, such as inflammatory bowel diseases (IBDs). Interleukin (IL)-17 is a potent inflammatory cytokine, and T-helper (Th)17 cells and other IL-17-producing cells are involved in the pathogenesis of IBD. Multiple mechanisms of action have been suggested to explain the protective anti-inflammatory effects of probiotics in intestinal inflammation, including the immunoregulation and suppression of Th17 activity and IL-17 production in part by signaling through pattern-recognition receptors such as Toll-like receptor family. However, steady-state Th17 cells have an important role in host defense against fungi and bacteria. Interestingly, recent studies revealed that specific commensal bacterial species such as segmented filamentous bacteria (SFB) induce the accumulation of Th17 cells in the small intestine in many species, including mice. It is important to determine the mechanisms by which intestinal Th17 cells are induced by SFB and whether these or other bacteria with similar properties are present in the human intestine. This brief review focuses on the interaction between probiotics/microbiota and Th17 cells during inflammation (war) and during steady-state homeostatic regulation (peace). © 2013 Informa Healthcare USA, Inc.
Ohashi N.,Hiroshima University
JACC. Cardiovascular imaging | Year: 2010
We sought to investigate the association between visceral adipose tissue (VAT) with the presence, extent, and characteristics of noncalcified coronary plaques (NCPs) using 64-slice computed tomography angiography (CTA). Although visceral adiposity is associated with cardiovascular events, its association with NCP burden and vulnerability is not well known. The study population consisted of 427 patients (age 67 ± 11 years; 63% men) with proven or suspected coronary artery disease who underwent 64-slice CTA. We assessed the presence and number of NCPs for each patient. The extent of NCP was tested for the difference between high (≥ 2) and low (≤ 1) counts. We further evaluated the vulnerable characteristics of NCPs with positive remodeling (remodeling index >1.05), low CT density (≤ 38 HU), and the presence of adjacent spotty calcium. Plain abdominal scans were also performed to measure the VAT and subcutaneous adipose tissue area. A total of 260 (61%) patients had identifiable NCPs. Multivariate analyses revealed that increased VAT area (per 1 standard deviation, 58 cm(2)) was significantly associated with both the presence (odds ratio [OR]: 1.68; 95% confidence interval [CI]: 1.28 to 2.22) and extent (OR: 1.31; 95% CI: 1.03 to 1.68) of NCP. Other body composition measures, including subcutaneous adipose tissue area, body mass index, and waist circumference were not significantly associated with either presence or extent of NCP. Increased VAT area was also independently associated with the presence of NCP with positive remodeling (OR: 1.71; 95% CI: 1.18 to 2.53), low CT density (OR: 1.69; 95% CI: 1.17 to 2.47), and adjacent spotty calcium (OR: 1.52; 95% CI: 1.03 to 2.27). Increased VAT area was significantly associated with NCP burden and vulnerable characteristics identified by CTA. Our findings may explain the excessive cardiovascular risk in patients with visceral adiposity, and support the potential role of CTA to improve risk stratification in such patients. Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
Kondo T.,Hiroshima University
Proceedings. Biological sciences / The Royal Society | Year: 2012
Livistona mariae is an endemic palm localized in arid central Australia. This species is separated by about 1000 km from its congener L. rigida, which grows distantly in the Roper River and Nicholson-Gregory River catchments in northern Australia. Such an isolated distribution of L. mariae has been assumed to have resulted from contraction of ancestral populations as Australia aridified from the Mid-Miocene (ca 15 Ma). To test this hypothesis at the population level, we examined the genetic relationships among 14 populations of L. mariae and L. rigida using eight nuclear microsatellite loci. Our population tree and Bayesian clustering revealed that these populations comprised two genetically distinct groups that did not correspond to the current classification at species rank, and L. mariae showed closest affinity with L. rigida from Roper River. Furthermore, coalescent divergence-time estimations suggested that the disjunction between the northern populations (within L. rigida) could have originated by intermittent colonization along an ancient river that has been drowned repeatedly by marine transgression. During that time, L. mariae populations could have been established by opportunistic immigrants from Roper River about 15 000 years ago, concurrently with the settlement of indigenous Australians in central Australia, who are thus plausible vectors. Thus, our results rule out the ancient relic hypothesis for the origin of L. mariae.