Publications by authors named "Kyoko Sugai"

The Bonin Islands, comprised of the Mukojima, Chichijima, and Hahajima Islands, are known for their isolated and distinctive habitats, hosting a diverse array of endemic flora and fauna. In these islands, adaptive radiation has played a remarkable role in speciation, particularly evident in the genus that is represented by three species: and exclusive to the Chichijima Islands, and , distributed across the entire Bonin Islands. Notably, exhibits multiple ecotypes, differing in leaf hair density, flowering time, and tree size.

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In some squids, such as those in the family Loliginidae, upon copulation, females receive and store male-delivered sperm capsules, spermatangia, at two different body locations: the buccal membrane and the distal end of the oviduct. This insemination site dimorphism is associated with alternative reproductive strategies. However, in Loliolus sumatrensis, a species of Loliginidae, the females possess three insemination sites: buccal membrane (BM), basal left IV arm (ARM) and lateral head behind the left eye (EYE), therefore we studied such the unusual phenomena.

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Callicarpa subpubescens, endemic to the Ogasawara Islands, is suggested to have multiple ecotypes in the Hahajima Islands, specifically in the central part of the Ogasawara Islands. In this study, associations between genetic groups and spatial distribution, habitat, leaf morphology, size structure, and flowering time of each genetic group were investigated on Hahajima and the satellite Imoutojima Islands. Genetic groups were identified using EST-SSR markers, revealing four ecotypes named based on morphological features: Dwarf (D), Glabrescent (G), Tall (T), and Middle (M), with M being a result of the hybridization of G and T.

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Island biogeography research provides insight into microbial diversity patterns; however, little is known about the diversity and distribution of soil microbial communities on remote and poorly accessible islands. Here, we present amplicon sequencing data from bacterial and fungal communities in the surface soils of the Ogasawara (Bonin) Islands, Japan.

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Article Synopsis
  • * Researchers analyzed 668 individuals from 28 populations across 14 islands, using microsatellite markers, revealing that the Yaeyama Islands had the highest genetic diversity and the Volcano Islands the lowest.
  • * Findings indicate that younger oceanic islands tend to have lower genetic diversity due to limited gene flow and fewer unique alleles, while geographical patterns influence overall genetic structure among populations, especially in the Volcano Islands where isolation has led to significant genetic divergence.
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Pandanus boninensis, endemic to the Ogasawara Islands, Japan, is distributed on both the older Bonin and younger Volcano Islands. In this study, we conducted population genetic analyses of P. boninensis on these islands to examine the population diversity and structure across old and young islands, to assess potential differences in population demography with island age, and to collect any evidence of migration between old and young islands.

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Adaptive radiation is the diversification of a founding population into multiple taxa that are differentially adapted to diverse ecological niches. The three Callicarpa (Lamiaceae) species endemic to the Bonin Islands are considered to represent an example of adaptive radiation on oceanic islands. All three species are distributed in the Chichijima Island Group and grow in different habitats, while only one species, C.

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  • Researchers developed microsatellite markers for a dioecious shrub from the Rutaceae family, enabling identification of clonal relationships among its vegetative propagules.
  • Sixteen polymorphic microsatellite markers were created using advanced 454 next-generation sequencing, with varying alleles and heterozygosity among four populations.
  • These markers assist in studying clone identification, clonal structure, and true sex ratios in the wild, and five markers show potential for evaluating mating systems and parentage analysis.
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  • Distylium lepidotum is a small tree native to the Ogasawara Islands and serves as the primary food source for an endemic locust species, Boninoxya anijimensis.
  • Researchers developed microsatellite markers using next-generation sequencing to explore the genetic diversity and structure of D. lepidotum in two populations on Chichijima and Hahajima Islands.
  • The findings show varying numbers of alleles and levels of expected heterozygosity, indicating potential for future studies and helping with conservation efforts in the region.
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Premise Of The Study: Twenty-six microsatellite (simple sequence repeat [SSR]) markers were characterized in Psychotria homalosperma (Rubiaceae), an endemic evergreen tree in the Bonin Islands, Japan, to investigate the genetic structure and gene flow of the species.

Methods And Results: Using next-generation sequencing, we developed 26 SSR markers for P. homalosperma with perfect motifs from di- to pentanucleotide repeats.

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Gene flow between populations in different environmental conditions can be limited due to divergent natural selection, thus promoting genetic differentiation. Elaeocarpus photiniifolia, an endemic tree species in the Bonin Islands, is distributed in two types of habitats, dry scrubs and mesic forests. We aim to elucidate the genetic differentiation in E.

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Premise Of The Study: Expressed sequence tag (EST)-derived microsatellite markers were developed for Elaeocarpus photiniifolia, an endemic taxon of the Bonin Islands.

Methods And Results: Initially, a complementary DNA (cDNA) library was constructed by de novo pyrosequencing of total RNA extracted from a seedling. A total of 267 primer pairs were designed from the library.

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Premise Of The Study: To facilitate rapid development of microsatellite or simple sequence repeat (SSR) markers, an expressed sequence tags (EST) database was constructed for Pandanus boninensis, an evergreen tree endemic to the Bonin Islands, using pyrosequencing technology.

Methods And Results: We designed primers for 340 EST-SSRs identified from 109620 pyrosequencing reads, 48 of which were tested for PCR amplification. Thirty-four primers provided clear amplification, and 26 of those 34 displayed clear polymorphic patterns in sampled populations, with mean expected heterozygosity at the amplified loci ranging from 0.

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Article Synopsis
  • Researchers developed microsatellite markers from expressed sequence tags (ESTs) of the Schima mertensiana tree to study its population genetics.
  • Out of 683 EST-SSRs created from over 149,000 ESTs, 30 were successfully amplified and showed genetic variation among populations.
  • These new genetic markers will aid in future research on the genetic structure of S. mertensiana and its relatives.
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Premise Of The Study: Robust markers are required (inter alia) for assessing origins of Calophyllum inophyllum populations on the Bonin Islands, Japan. Therefore, informative expressed sequence tag (EST)-based microsatellite or simple sequence repeat (SSRs) markers in the species were sought.

Methods And Results: Using 135378 ESTs derived from de novo pyrosequencing, primers for 475 EST-SSRs were developed, 48 of which were tested for PCR amplification.

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We report a case of intestinal obstruction due to intramural hematoma of the duodenum following therapeutic endoscopy for a bleeding duodenal ulcer in a patient with liver cirrhosis. A 44-year-old man was admitted to our hospital with severe epigastralgia, nausea and tarry stool. Two years previously he had undergone endoscopic sclerotherapy for esophageal varices caused by alcoholic liver cirrhosis.

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