228 research outputs found
Effects of Probiotics on the Immune System and Allergic Diseases
ABSTRACTIntestinal microbiota play a crucial role in the development of mucosal tolerance and adaptation. Perturbations in microbiota composition are strongly associated with allergies and asthma in westernized countries. There has been accumulating evidence that the administration of probiotics, âlive microbial supplements that exert a beneficial effect on human health,â may be effective in the treatment and/or prevention of allergic diseases. Although it has been shown that part of the effect of probiotics arises from its interaction with the host immune system, the precise mechanisms remain to be determined. In addition, future studies are necessary to define appropriate species and strains, optimum dose, frequency, and duration for the treatment of allergic diseases
A new kentriodontid (Cetacea: Odontoceti) from the early to middle Miocene of the western North Pacific and a revision of kentriodontid phylogeny
A new species of an extinct dolphin belonging to the kentriodontids, i.e., Kentriodon sugawarai sp. nov., is described from the upper lower to lowest middle Miocene Kadonosawa Formation in Ninohe City, Iwate Prefecture, northern Japan. The holotype of Kentriodon sugawarai sp. nov., consists of a partial skull with ear bones, mandibular fragments, and some postcranial bones. This new species shares five unique characters with other species of Kentriodon. In addition, the new species differs from other species of the genus in displaying a narrow width of the squamosal lateral to the exoccipital in posterior view, the dorsolateral edge of the opening of the ventral infraorbital foramen that is formed by the maxilla and the lacrimal or the jugal, and at least three anterior dorsal infraorbital foramina. Our phylogenetic analysis based on 393 characters for 103 Odontoceti taxa yielded a consensus tree showing all previously identified kentriodontids as a monophyletic group that comprises the sister group of the crown Dephinoidea, which in turn include Delphinidae, Phocoenidae and Monodontidae. Our analysis also indicates that the distinct innovation of the acoustic apparatus (i.e., 13 out of 29 derived characters are from tympanoperiotic) would have occurred in the ancestral lineage of the Delphinoidea (sensu lato) including the monophyletic Kentriodontidae during their initial evolution and diversification
Ancient DNA reveals multiple origins and migration waves of extinct Japanese brown bear lineages.
Little is known about how mammalian biogeography on islands was affected by sea-level fluctuations. In the Japanese Archipelago, brown bears (Ursus arctos) currently inhabit only Hokkaido, the northern island, but Pleistocene fossils indicate a past distribution throughout Honshu, Japan's largest island. However, the difficulty of recovering ancient DNA from fossils in temperate East Asia has limited our understanding of their evolutionary history. Here, we analysed mitochondrial DNA from a 32 500-year-old brown bear fossil from Honshu. Our results show that this individual belonged to a previously unknown lineage that split approximately 160 Ka from its sister lineage, the southern Hokkaido clade. This divergence time and fossil record suggest that brown bears migrated from the Eurasian continent to Honshu at least twice; the first population was an early-diverging lineage (greater than 340 Ka), and the second migrated via Hokkaido after approximately 160 Ka, during the ice age. Thus, glacial-age sea-level falls might have facilitated migrations of large mammals more frequently than previously thought, which may have had a substantial impact on ecosystem dynamics in these isolated islands
Phylogeographic and Demographic Analysis of the Asian Black Bear (Ursus thibetanus) Based on Mitochondrial DNA.
The Asian black bear Ursus thibetanus is widely distributed in Asia and is adapted to broad-leaved deciduous forests, playing an important ecological role in the natural environment. Several subspecies of U. thibetanus have been recognized, one of which, the Japanese black bear, is distributed in the Japanese archipelago. Recent molecular phylogeographic studies clarified that this subspecies is genetically distantly related to continental subspecies, suggesting an earlier origin. However, the evolutionary relationship between the Japanese and continental subspecies remained unclear. To understand the evolution of the Asian black bear in relation to geological events such as climatic and transgression-regression cycles, a reliable time estimation is also essential. To address these issues, we determined and analyzed the mt-genome of the Japanese subspecies. This indicates that the Japanese subspecies initially diverged from other Asian black bears in around 1.46Ma. The Northern continental population (northeast China, Russia, Korean peninsula) subsequently evolved, relatively recently, from the Southern continental population (southern China and Southeast Asia). While the Japanese black bear has an early origin, the tMRCAs and the dynamics of population sizes suggest that it dispersed relatively recently in the main Japanese islands: during the late Middle and Late Pleistocene, probably during or soon after the extinction of the brown bear in Honshu in the same period. Our estimation that the population size of the Japanese subspecies increased rapidly during the Late Pleistocene is the first evidential signal of a niche exchange between brown bears and black bears in the Japanese main islands. This interpretation seems plausible but was not corroborated by paleontological evidence that fossil record of the Japanese subspecies limited after the Late Pleistocene. We also report here a new fossil record of the oldest Japanese black bear from the Middle Pleistocene, and it supports our new evolutionary hypothesis of the Japanese black bear
Molecular analysis of cyclic α-maltosyl-(1â6)-maltose binding protein in the bacterial metabolic pathway
Cyclic α-maltosyl-(1â6)-maltose (CMM) is a cyclic glucotetrasaccharide with alternating α-1,4 and α-1,6 linkages. Here, we report functional and structural analyses on CMM-binding protein (CMMBP), which is a substrate-binding protein (SBP) of an ABC importer system of the bacteria Arthrobacter globiformis. Isothermal titration calorimetry analysis revealed that CMMBP specifically bound to CMM with a Kd value of 9.6 nM. The crystal structure of CMMBP was determined at a resolution of 1.47 Ă
, and a panose molecule was bound in a cleft between two domains. To delineate its structural features, the crystal structure of CMMBP was compared with other SBPs specific for carbohydrates, such as cyclic α-nigerosyl-(1â6)-nigerose and cyclodextrins. These results indicate that A. globiformis has a unique metabolic pathway specialized for CMM
Reactivity of IgE in fish-allergic patients to fish muscle collagen
ABSTRACTBackground: In addition to parvalbumin, the well- known major allergen in fish, collagen was recently identified as a new allergen in the muscle of bigeye tuna and in the skin of several species of fish. The aim of the present study was to evaluate fish muscle colla- gens for their reactivity with IgE in fish-allergic patients and antigenic cross-reactivity.Methods: Collagen was purified from the white muscle of five species of fish (Japanese eel, alfonsin, mackerel, skipjack and bigeye tuna) by acid extraction and salt precipitation, whereas parvalbumin was purified from bigeye tuna by gel filtration and reverse- phase HPLC. The IgE reactivities to collagen and parvalbumin were examined by ELISA, whereas antigenic cross-reactivity among fish muscle collagens was investigated by ELISA inhibition experiments.Results: When 15 sera from fish-allergic patients were subjected to ELISA using bigeye tuna collagen and parvalbumin, 10 sera reacted only to parvalbumin, two reacted only to collagen, two reacted to both collagen and parvalbumin and one reacted to neither collagen nor parvalbumin. The sera containing specific IgE to bigeye tuna collagen also reacted to collagens from the other four species of fish. In the ELISA inhibition experiments, bigeye tuna collagen inhibited the binding of IgE not only to bigeye tuna collagen, but also to that from the other four species of fish, suggesting cross-reactivity among the collagens from five species of fish.Conclusions: These results demonstrate that some Japanese fish-allergic patients have specific IgE to fish muscle collagen and that fish muscle collagen is a cross-reactive allergen among various species of fish
Magnifying endoscopic observation of primary follicular lymphoma of the duodenum by using the narrow-band imaging system.
Three Cases of Tsutsugamushi Disease successfully treated with Clarithromycin.
Three cases of tsutsugamushi disease were successfully treated with clarithromycin, a new macrolide antibiotic. This is the first report describing tsutsugamushi disease in Hirado area and the clinical application of clarithromycin to this rickettsial disease
Peyerâs Patches in the Terminal Ileum in Ulcerative Colitis: Magnifying Endoscopic Findings
Peyerâs patches (PPs), a major component of the gut-associated lymphoid tissue, serve as important antigen entry sites in mucosal immunity. PPs may play a role in the extension of ulcerative colitis (UC) into the terminal ileum. We sought to clarify the magnified endoscopic findings of the PPs in the terminal ileum of UC patients. Eighteen UC patients underwent magnifying chromoendoscopy before initial treatment to evaluate the follicle-associated epithelium (FAE) on the PPs domes and the surrounding villi. In 8 UC patients, as in healthy controls, the PPsâ domes were slightly elevated, covered with the regular FAE lining, and surrounded by dense and bulky villi; however, in 10 UC patients, the PPsâ domes were irregular, and the surrounding villi were sparse and atrophic. These abnormal findings within the PPs were associated with minimal mucosal lesions but not with backwash ileitis; both electron microscopy and magnifying endoscopy confirmed that these lesions were reversible following remission with prednisolone-mesalazine therapy. Similar to Crohnâs disease patients, UC patients commonly had abnormalities in the FAE on PPsâ domes and the surrounding villi on magnifying endoscopy
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