Publications by authors named "Tatsunori Masatani"

Article Synopsis
  • Piroplasmas, like Babesia and Theileria, are protozoan parasites transmitted by ticks to warm-blooded animals, with some species capable of causing zoonotic infections in humans.
  • This study collected wild rodents and ticks near Gifu City, Japan, from 2021 to 2023, using a technique called nested-PCR to identify specific piroplasma gene sequences.
  • Results showed that B. microti was present in field mice, and related piroplasmas potentially harmful to humans were also found in ticks, indicating the distribution of these pathogens in the area.
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Article Synopsis
  • The study focuses on Toxoplasma gondii type I strains, which are highly lethal to laboratory mice, and questions whether resistant rodent populations can exist in the wild.
  • Researchers hypothesized that wild mice in various global regions, particularly in Japan, could harbor type I strains without showing symptoms.
  • Genetic analysis of mice from Gifu and Okinawa Prefectures revealed diverse Irgb2 gene sequences, indicating that resistant mouse populations may be present in Japan, alongside known resistant populations in South Asia.
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Avian rotaviruses A (RVAs) are occasionally transmitted to animals other than the original hosts across species barriers. Information on RVAs carried by various bird species is important for identifying the origin of such interspecies transmission. In this study, to facilitate an understanding of the ecology of RVAs from wild birds, we characterized all of the genes of an RVA strain, JC-105, that was detected in a fecal sample of a large-billed crow (Corvus macrorhynchos) in Japan.

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Macroautophagy (hereafter autophagy) is an intracellular degradative pathway in budding yeast cells. Certain lipid types play essential roles in autophagy; yet the precise mechanisms regulating lipid composition during autophagy remain unknown. Here, we explored the role of the Osh family proteins in the modulating lipid composition during autophagy in budding yeast.

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Akabane virus (AKAV) is a member of the genus Orthobunyavirus, family Peribunyaviridae. In addition to AKAV strains that cause fetal Akabane disease, which is characterized by abortion in ruminants, some AKAV strains cause postnatal infection characterized by nonsuppurative encephalomyelitis in ruminants. Here, we focused on the NSs protein, a virulence factor for most viruses belonging to the genus Orthobunyavirus, and we hypothesized that this protein would act as a neurovirulence factor in AKAV strains causing postnatal encephalomyelitis.

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is an intracellular protozoan parasite causing toxoplasmosis, an infectious disease affecting warm-blooded vertebrates worldwide. Many drug-metabolizing enzymes are located in the liver, a major organ of drug metabolism, and their function can be affected by pathogen infection.Using next-generation sequencing (RNA-seq) and quantitative polymerase chain reaction (qPCR), changes in the hepatic expressions of drug-metabolizing enzymes were analysed in mice chronically infected with .

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In reptiles, infection with Cryptosporidium parasite can be lethal, especially in species of family Eublepharidae such as Eublepharis macularius and Goniurosaurus splendes species. We investigated the presence of Cryptosporidium spp. in wild reptiles, especially Goniurosaurus spp.

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Toxoplasma gondii is a highly prevalent obligate apicomplexan parasite that is important in clinical and veterinary medicine. It is known that glycerophospholipids phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEtn), especially their expression levels and flip-flops between cytoplasmic and exoplasmic leaflets, in the membrane of T. gondii play important roles in efficient growth in host mammalian cells, but their distributions have still not been determined because of technical difficulties in studying intracellular lipid distribution at the nanometer level.

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Live rabies vaccines have advantageous features that can facilitate mass vaccination for dogs, the most important reservoirs/transmitters of rabies. However, some live vaccine strains have problems in their safety, namely, risks from the residual pathogenicity and the pathogenic reversion of live vaccine strains. The reverse genetics system of rabies virus provides a feasible option to improve the safety of a live vaccine strain by, for example, artificially introducing attenuating mutations into multiple viral proteins.

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Newcastle disease caused by highly pathogenic viruses of avian paramyxovirus serotype-1 (APMV-1) is a highly contagious poultry disease. Although a large-scale epidemic of Newcastle disease had occurred in Japan between the 1950s and the 2000s, there have been no outbreaks anywhere since 2010. In addition, there are no reports of epidemiological surveys of APMV-1 in wild birds in Japan in the last 10 years.

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Bovine respiratory syncytial virus (BRSV) strains that were detected in Kagoshima prefecture and isolated in Hokkaido between 2017 and 2019, together with a BRSV vaccine strain, were subjected to full-genome sequencing. The BRSV strains identified in Japan were found to be genetically close to each other but distant from the vaccine strains. The deduced amino acids at positions 206 and 208 of the glycoprotein (G protein), which form one of the major epitopes of the recent Japanese BRSV strains, were different from those of the vaccine strains.

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A recent study demonstrated the possibility that migratory birds are responsible for the global spread of avian rotavirus A (RVA). However, little is known about what types of RVAs are retained in migratory birds. In this study, to obtain information on RVA strains in migratory birds, we characterised an RVA strain, Ho374, that was detected in a faecal sample from a gull species ( sp.

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The rabies virus strain Komatsugawa isolated from a dog in Tokyo in the 1940s retains biological properties as a field strain, providing an effective model for studying rabies pathogenesis. To facilitate molecular studies on the pathogenesis, this study aimed to establish a reverse genetics system for the Komatsugawa strain. By transfecting the full-length genome plasmid of this strain, infectious virus with artificially introduced genetic markers in its genome was rescued.

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Stress granules (SGs) are dynamic structures that store cytosolic messenger ribonucleoproteins. SGs have recently been shown to serve as a platform for activating antiviral innate immunity; however, several pathogenic viruses suppress SG formation to evade innate immunity. In this study, we investigated the relationship between rabies virus (RABV) virulence and SG formation, using viral strains with different levels of virulence.

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Avian rotavirus A (RVA) is one of major enteric pathogens that cause diarrhoea in young avian individuals. Importantly, some of the avian RVA strains of G18P[17] genotype are naturally transmitted to and cause clinical diseases in mammalian species, indicating their potential risks to animal health. Although molecular information on the pathogenesis by avian RVA strains will be useful for estimating their risks, the absence of a reverse genetics (RG) system for these strains has hindered the elucidation of their pathogenic mechanisms.

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Environmental water-targeted surveillance of migratory aquatic birds at overwintering sites is potentially one of the most effective approaches for understanding the ecology of avian influenza viruses (AIVs). In this study, we improved the method for AIV isolation from environmental water samples by making a minor modification to our previously reported process. We experimentally demonstrated that the AIV recovery efficiency of the modified method was 10-100-fold higher than that of the original method.

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Article Synopsis
  • Crane-associated adenovirus 1 (CrAdV-1) was discovered in hooded cranes in Japan and is notable for its widespread prevalence among various crane species in the region during winter.
  • Genetic analysis indicates that CrAdV-1 shows distinct phylogenetic differences from other aviadenoviruses, with a significant increase in prevalence particularly among juvenile cranes over the winter months.
  • The virus primarily affects the colon, cerebrum, trachea, lungs, and heart of cranes, suggesting it spreads mainly through fecal-oral and airborne routes.
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Autophagy is regulated by phosphoinositides. We have previously shown that phosphatidylinositol 4-phosphate (PtdIns(4)P) is localized in the autophagosomal membrane. Additionally, in yeast cells, phosphatidylinositol 4-kinases Pik1p and Stt4p play important roles in the formation of the autophagosome and its fusion with the vacuole, respectively.

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Diseases caused by tick-transmitted pathogens including bacteria, viruses, and protozoa are of veterinary and medical importance, especially in tropical and subtropical regions including Turkey. Hence, molecular surveillance of tick-borne diseases will improve the understanding of their distribution towards effective control. This study aimed to investigate the presence and perform molecular characterization of Babesia sp.

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and are tick-borne protozoan parasites that can cause significant economic losses in the cattle industry. This study aimed to contribute to the limited epidemiological data on as well as and in large ruminants in the Philippines. Blood samples of 412 cattle and 108 water buffalo collected from four provinces in Southern Luzon, Philippines, were initially tested for the gene of piroplasms through nested PCR.

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Article Synopsis
  • Researchers found that avian G18P[17] rotaviruses, which can cause disease in mammals, have similar genetic makeups across the globe.
  • The study focused on a rotavirus strain called RK1, collected from migratory velvet scoter birds in Japan, and showed that its genetic characteristics are in line with G18P[17] strains found worldwide.
  • The RK1 strain was shown to cause diarrhea in suckling mice, suggesting that migratory birds could play a significant role in spreading these infectious and pathogenic rotaviruses to mammals.
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Rabies has almost a 100% case-fatality rate and kills more than 59,000 people annually around the world. There is no established treatment for rabies. The rabies virus (RABV) expresses only the glycoprotein (RABVG) at the viral surface, and it is the target for the neutralizing antibodies.

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Article Synopsis
  • In yeast cells, the autophagosome transforms into the autophagic body inside the vacuole, where its membrane is degraded by vacuolar enzymes.
  • The study used electron microscopy to analyze four phospholipids within autophagosomal and autophagic body membranes during autophagy.
  • Results showed a significant rise in phosphatidylserine (PtdSer) levels in the autophagic body membrane, indicating a selective increase that may explain the targeted degradation of the autophagic membrane while maintaining low levels in the vacuolar membrane.
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Lipid rafts, sterol-rich and sphingolipid-rich microdomains on the plasma membrane are important in processes like cell signaling, adhesion, and protein and lipid transport. The virulence of many eukaryotic parasites is related to raft microdomains on the cell membrane. In the malaria parasite Plasmodium falciparum, glycosylphosphatidylinositol-anchored proteins, which are important for invasion and are possible targets for vaccine development, are localized in the raft.

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Rabies virus phosphoprotein (P protein) is a multifunctional protein that plays key roles in replication as the polymerase cofactor that binds to the complex of viral genomic RNA and the nucleoprotein (N protein), and in evading the innate immune response by binding to STAT transcription factors. These interactions are mediated by the C-terminal domain of P (PCTD). The colocation of these binding sites in the small globular PCTD raises the question of how these interactions underlying replication and immune evasion, central to viral infection, are coordinated and, potentially, coregulated.

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