Publications by authors named "Ai Takano"

Background And Purpose: Clinical manifestations of Lyme borreliosis (LB), caused by Borrelia burgdorferi sensu lato (Bbsl), include erythema migrans, Lyme neuroborreliosis (LNB), carditis, and arthritis. LB is a notifiable disease in Japan with <30 surveillance-reported LB cases annually, predominately from Hokkaido Prefecture. However, LB, including LNB, may be under-diagnosed in Japan since diagnostic tests are not readily available.

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The correct delineation of tick species is critical for efforts aimed at safeguarding One Health. Historically, the Asian turtle tick (Amblyomma geoemydae sensu lato) has been regarded as a geographically widespread species across much of Asia. However, based on morphological and phylogenomic data, the subtropical lineage (from Japan, Taiwan, and parts of China) of A.

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Migratory birds carry ticks harboring various pathogens, including the zoonotic Yezo virus. In Hokkaido, Japan, we collected ticks from migratory birds during 2020-2021. Eight of 385 pools, comprising 2,534 ticks, tested positive for Yezo virus RNA, suggesting Yezo virus might be spread through the flyways of migratory birds.

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Orientia tsutsugamushi (OT) is an obligate intracellular bacterium transmitted by larval trombiculid mites, responsible for scrub typhus in humans. In Japan, approximately 500 human cases are reported annually, with six major serotypes identified as Kato, Karp, Gilliam, Irie/Kawasaki, Shimokoshi, and Hirano/Kuroki. However, the prevalence of OT in Yamaguchi prefecture remains largely unknown.

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Historically, for more than one and a half centuries, only one so-called "long-legged bat tick" species, i.e., Koch was known to science.

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Article Synopsis
  • * The study examined 132 bats from 4 species in Yamaguchi Prefecture using PCR methods to detect various viruses.
  • * Researchers identified herpesviruses, adenoviruses, astroviruses, and coronaviruses, finding 12 strains that are closely related to viruses from China and South Korea.
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Human pancreatic cancer is characterized by the molecular diversity encompassing native duct-like and squamous cell-like identities, but mechanisms underlying squamous transdifferentiation have remained elusive. To comprehensively capture the molecular diversity of human pancreatic cancer, we here profiled 65 patient-derived pancreatic cancer organoid lines, including six adenosquamous carcinoma lines. H3K27me3-mediated erasure of the ductal lineage specifiers and hijacking of the TP63-driven squamous-cell programme drove squamous-cell commitment, providing survival benefit in a Wnt-deficient environment and hypoxic conditions.

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Francisella tularensis is an intracellular gram-negative bacterium known as the causative agent of tularemia, which can be transmitted to humans by direct contact with wild animals or by tick bites. Although F. tularensis is highly pathogenic, its recent prevalence in Japan is underreported due to the small number of reported cases.

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  • * SAYAV was not able to be cultured in lab settings but was studied by creating single-round infectious virus particles (SRIP) using its gene sequence, which helped in examining its endemic status.
  • * The presence of neutralizing antibodies against SAYAV in sika deer and wild boars indicates it is widespread in Japan, and phylogenetic analysis shows it evolved separately from other known flaviviruses, highlighting an innovative approach to studying uncultured viruses.
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  • The study investigates ixodid ticks associated with bat families in Eurasia, revealing significant genetic differences among tick species across different regions, particularly in Eastern Asia.
  • By conducting detailed morphological comparisons and analyzing molecular and phylogenetic relationships, the researchers identified and described three new tick species previously thought to be variations of existing ones.
  • The findings indicate that these new species exhibit high genetic divergence, particularly in the cytochrome oxidase subunit (coxI) gene, which supports their classification as separate species based on both genetic and morphological lines.
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Background: Borrelia are important disease-causing tick- and louse-borne spirochaetes than can infect a wide variety of vertebrates, including humans and reptiles. Reptile-associated (REP) Borrelia, once considered a peculiarity, are now recognised as a distinct and important evolutionary lineage, and are increasingly being discovered worldwide in association with novel hosts. Numerous novel Borrelia spp.

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  • "Candidatus Rickettsia kotlanii" is a newly identified tick-borne pathogen associated with spotted fever, first found in Hungary in 2006.
  • Researchers sequenced the complete genomes of two Japanese isolates to clarify its evolutionary relationship within the spotted fever group of Rickettsia, revealing that it forms an independent branch within this category.
  • Despite having nearly identical genomes, the isolates came from different tick species and locations, indicating low genetic diversity, while some genes present in "Ca. R. kotlanii" were found to be degraded, necessitating further study on its unique features.
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Background & Aims: In the mouse intestinal epithelium, Lgr5 stem cells are vulnerable to injury, owing to their predominantly cycling nature, and their progenies de-differentiate to replenish the stem cell pool. However, how human colonic stem cells behave in homeostasis and during regeneration remains unknown.

Methods: Transcriptional heterogeneity among colonic epithelial cells was analyzed by means of single-cell RNA sequencing analysis of human and mouse colonic epithelial cells.

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Bats (order, Chiroptera) account for more than one-fifth of all mammalian species in the world and are infected by various intra-erythrocytic parasites of the family Plasmodiidae (Apicomplexa: Haemosporida), including Polychromophilus Dionisi, 1899. Recent advance in the molecular characterization of haemosporidian isolates has enabled their accurate identification, particularly in the last decade. Studies are actively conducted in tropical regions, Europe, and Australia; however, data on haemosporidian infection in bats in Asian temperate areas, including Japan, remain limited.

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Cancer relapse after chemotherapy remains a main cause of cancer-related death. Although the relapse is thought to result from the propagation of resident cancer stem cells, a lack of experimental platforms that enable the prospective analysis of cancer stem cell dynamics with sufficient spatiotemporal resolution has hindered the testing of this hypothesis. Here we develop a live genetic lineage-tracing system that allows the longitudinal tracking of individual cells in xenotransplanted human colorectal cancer organoids, and identify LGR5 cancer stem cells that exhibit a dormant behaviour in a chemo-naive state.

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  • * A retrospective surveillance revealed that a significant percentage of the tested animals had antibodies against SFTSV: 510 out of 789 sika deer and 199 out of 517 wild boars.
  • * The findings suggest that SFTSV had been present in wild animals prior to 2012, with a noticeable increase in infection rates in sika deer from 2010-2013 to 2015-2020, indicating a gradual spread of the virus in the area
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In Japan, hepatitis E virus (HEV) causes hepatitis in humans through the consumption of raw or undercooked meat, including game meat. In the present study, nationwide surveillance of HEV infection among a total of 5,557 wild animals, including 15 species, was conducted in Japan. The prevalence of anti-HEV antibodies in wild boar was 12.

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Research on vector-associated microbiomes has been expanding due to increasing emergence of vector-borne pathogens and awareness of the importance of symbionts in the vector physiology. However, little is known about microbiomes of argasid (or soft-bodied) ticks due to limited access to specimens. We collected four argasid species (, , , and ) from the nests or burrows of their vertebrate hosts.

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  • Precision oncology aims to predict how effectively drugs will work based on the molecular characteristics of tumors, but it's unclear how well patient-derived tumor organoids mimic real tumors' responses to drugs.
  • * Researchers developed a drug screening platform using patient-derived colorectal organoids to study human colorectal cancer (CRC), refining culture conditions for better scalability and inclusion of normal organoids.
  • * The study revealed that a BET protein inhibitor selectively suppresses cancer growth and highlighted a link between CHFR gene silencing and sensitivity to paclitaxel, emphasizing the importance of thorough validation in drug screening.
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Oz virus is a novel thogotovirus isolated from ticks that causes lethal infection in mice. We conducted serosurveillance of Oz virus infection among humans and wild mammals in Japan using virus-neutralization tests and ELISAs. Results showed that Oz virus may be naturally infecting humans and other mammalian hosts.

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  • Kabuto Mountain virus (KAMV) was first isolated from ticks in Japan in 2018, and there's no prior information on its infection in humans or animals.
  • A serological survey conducted in Yamaguchi Prefecture found KAMV in various species, with positive infection rates of 20.8% in humans and notable rates in wild boars (33.9%) and monkeys (3.4%).
  • The study also determined that KAMV or a similar virus may be circulating among wildlife and ticks, with the potential for incidental human infection.
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Rabbit hepatitis E virus (HEV) has been detected among rabbits and recently isolated from immunocompromised patients, suggesting zoonotic transmission. In this study, HEV infection among feral rabbits (Oryctolagus cuniculus) was assessed by detection of anti-HEV antibodies and HEV RNA. The prevalence of anti-HEV antibodies in sera was of 33 % (20/60) and HEV RNA was detected from only one of fecal swabs (1.

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The taxonomy of ruminant Trypanosoma theileri and its relatives (Kinetoplastida: Trypanosomatidae) is controversial, with recent phylogenetic studies segregating T. theileri in cattle and other ruminants worldwide into two major genetic lineages (the TthI and TthII clades) based on genetic markers. In the present study, T.

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Background: Relapsing fever (RF) borreliae are arthropod-borne spirochetes and some of them cause human diseases, which are characterized by relapsing or recurring episodes of fever. Recently, it has been classified into two groups: soft tick-borne RF (STRF) borreliae and hard tick-borne RF (HTRF) borreliae. STRF borreliae include classical RF agents and HTRF borreliae, the latter of which include B.

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Borrelia miyamotoi, a member of the tick-borne relapsing fever spirochetes, shows a serum-resistant phenotype in vitro. This ability of B. miyamotoi may contribute to bacterial evasion of the host innate immune system.

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