Consulta: creatorFacets:"Yokoyama, Naoaki"
Registros recuperados: 31
Data/hora: 11/06/2024 09:28:25

Adjuvant Effect of Oligomannose-Coated Liposome-Based Platform for veccine against African Trypanosomosis
Provedor de dados: 19
Autores: Kuboki, Noritaka; Yokoyama, Naoaki; Namangala, B; Okamura, Masashi; Inoue, Noboru; Takagi, Hideaki; Nakayama, Tomoko; Nishikawa, Yoshifumi; Ikehara, Yuzuru; Kojima, Naoya; 横山, 直明; 井上, 昇; 西川, 義文.
Palavras-chave: Adjuvant; African trypanosome; Immunization; Oligomannose-coated liposome(OML).
Ano: 2008
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2222

Type-specific PCR assays for Babesia bovis msa-1 genotypes in Asia: Revisiting the genetic diversity in Sri Lanka, Mongolia, and Vietnam
Provedor de dados: 19
Autores: Liyanagunawardena, Nilukshi; Sivakumar, Thillaiampalam; Kothalawala, Hemal; Silva, Seekkuge Susil Priyantha; Battsetseg, Badgar; Dinh Thi Bich Lan; Inoue, Noboru; Igarashi, Ikuo; Yokoyama, Naoaki.
Babesia bovis is the most virulent Babesia organism, resulting in a high mortality rate in cattle. The genetic diversity of B. bovis merozoite surface antigens (MSAs), such as MSA-1, MSA-2b, and MSA-2c, might be linked to altered immune profiles in the host animals. The present study aimed to develop type-specific PCR assays for Asian msa-1 genotypes, thereby re-analyzing the genetic diversity of msa-1 in Sri Lanka, Mongolia, and Vietnam. Specific primers were designed for nine Asian msa-1 genotypes, which had been detected based on the phylogeny constructed using msa-1 gene sequences retrieved from the GenBank database. Specificity of the type-specific PCR assays was confirmed using plasmids containing the inserts of msa-1 gene fragments that represent...
Palavras-chave: Asia; Babesia bovis; Genetic diversity; Msa-1; Type-specific PCR.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4489

Preliminary evaluation of oligomannose-coated liposome vaccines against lethal protozoan infections in mice
Provedor de dados: 19
Autores: Kuboki, Noritaka; Tiwananthagorn, Weerawan; Takagi, Hideaki; Nakayama, Tomoko; Xuan, Xuenan; Inoue, Noboru; Igarashi, Ikuo; Tsujimura, Kunio; Ikehara, Yuzuru; Kojima, Naoya; Yokoyama, Naoaki.
The oligomannose-coated liposome (OML) vaccine is known to induce cellular immunity specific for the encapsulated antigen in immunized mice. In the present study, we preliminarily evaluated the effect of the OML vaccine encapsulating the soluble protozoan lysate of Toxoplasma gondii, Trypanosoma brucei gambiense, or Babesia rodhaini on the corresponding protozoan infections in mice. After the challenge of T. gondii, the OML vaccine group avoided the high mortality resulting from acute infection that was dominantly observed in other control groups. During the infectious course, the development of the T. gondii-specific antibody, which is an indicator of humoral immunity, was constantly controlled at a lower level in the surviving mice of the OML vaccine...
Palavras-chave: Oligomannose-coated liposome (OML); OML; Soluble protozoan antigen; Antibody responses.
Ano: 2007
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/1050

A PCR-based survey of animal African trypanosomosis and selected piroplasm parasites of cattle and goats in Zambia
Provedor de dados: 19
Autores: Musinguzi, Simon Peter; Suganuma, Keisuke; Asada, Masahito; Laohasinnarong, Dusit; Sivakumar, Thillaiampalam; Yokoyama, Naoaki; Namangala, Boniface; Sugimoto, Chihiro; Suzuki, Yasuhiko; Xuan, Xuenan; Inoue, Noboru.
We screened cattle and goats from the districts of Chama, Monze and Mumbwa in Zambia for animal African trypanosomes, Babesia bigemina and Theileria parva using PCRs; 38.1% of the samples tested positive for at least one of the parasite species. The most common parasite was Trypanosoma vivax (19.8%). Its incidence was significantly higher in goats than in cattle, (P&lt;0.05). B. bigemina was found in samples from all the three areas, making it the most widespread of the parasites in Zambia. Among the tested samples, 12.0% of the positive samples were mixed infections. There were significant differences in the infection rates of T. vivax (Mumbwa had a significantly higher infection rate [39.6%, P&lt;0.0001]), Th. parva (Monze had the only cases...
Palavras-chave: Animal African trypanosomosis; Cattle; Goat; Piroplasmosis; Zambia.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4389

TRANSIENT EXPRESSION OF A GREEN FLUORESCENT PROTEIN GENE IN BABESIA BOVIS
Provedor de dados: 19
Autores: Fujii, Kei; Yokoyama, Naoaki; Takabatake, Noriyuki; Suzuki, Hiroshi; Xuan, Xuenan; Igarashi, Ikuo; 横山, 直明; 鈴木, 宏志; 玄, 学南; 五十嵐, 郁男.
In hemoprotozoa，gene transfer technology provides an important tool to aid in the functional study of parasite genes. In this study，a transfer vector containing the enhanced green fluorescent protein (EGFP) gene laid between the Toxoplasma gondii GRAI promoter region and the GRA2 polyA signal region was constructed and transfected into the in vitro culture of Babesia boνis by the electroporation method.On the first and second days post-transfection，clear positive fluorescences were detected in some parasite bodies， indicating the successful expression of the EGFP gene controlled by the GRA-1 promoter in B. bovis. However， the positive parasites were not ubiquitous and finally disappeared until the forth day post-transfection. This is the first time that...
Ano: 2003
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/631

Genetic diversity and antigenicity variation of Babesia bovis merozoite surface antigen-1 (MSA-1) in Thailand
Provedor de dados: 19
Autores: Tattiyapong, Muncharee; Sivakumar, Thillaiampalam; Takemae, Hitoshi; Simking, Pacharathon; Jittapalapong, Sathaporn; Igarashi, Ikuo; Yokoyama, Naoaki.
Babesia bovis, an intraerythrocytic protozoan parasite, causes severe clinical disease in cattle worldwide. The genetic diversity of parasite antigens often results in different immune profiles in infected animals, hindering efforts to develop immune control methodologies against the B. bovis infection. In this study, we analyzed the genetic diversity of the merozoite surface antigen-1 (msa-1) gene using 162 B. bovis-positive blood DNA samples sourced from cattle populations reared in different geographical regions of Thailand. The identity scores shared among 93 msa-1 gene sequences isolated by PCR amplification were 43.5-100%, and the similarity values among the translated amino acid sequences were 42.8-100%. Of 23 total clades detected in our...
Palavras-chave: Antigenicity variation; Babesia bovis; Msa-1; Genetic diversity; Thailand.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4490

IN VITRO GROWTH INHIBITORY EFFECTS OF COMBINED APPLICATIONS OF CLOTRIMAZOLE, KETOCONAZOLE, AND CLODINAFOP-PROPARGYL ON EQUINE BABESIA PARASITES
Provedor de dados: 19
Autores: Bork, Sabine; Yokoyama, Naoaki; Okamura, Masashi; Igarashi, Ikuo; 横山, 直明; 五十嵐, 郁男.
Recently，we reported the in vitro growth inhibitory effects of the imidazole derivatives，clotrimazole(CLT) and ketoconazole (KC)，and the herbicide，clodinafop-propargyl(CP)，against bovine and equine Babesia parasites. Additionally，in the bovine species，several combined applications of the CLT，KC，and CP were reported to significantly increase the inhibitory effects. In this study，similar combination tests were carried out in order to confirm possible synergistic effects in the equine species，Babesia caballi and Babesia equi. Combinations of CLT/KC， CLT/CP，and CLT/KC/CP exerted a significantly enhanced growth inhibitory efficacy in B. caballi，in contrast to B. equi，where no synergistic effects were observed in any of the combinations. Our results suggest that...
Palavras-chave: In vitro; Babesia; Clotrimazole; Ketoconazole; Clodinafop-propargyl.
Ano: 2003
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/637

Cellular localization of Babesia bovis rhoptry-associated protein 1 in the merozoite stage with immuno-electron microscopy
Provedor de dados: 19
Autores: Matsuo, Tomohide; Yokoyama, Naoaki; Suthisak, Boonchit; Fujisaki, Kozo; Igarashi, Ikuo.
We examined the detailed cellular localization of the rhoptry-associated protein-1 (RAP-1) of Babesia bovis merozoites by the post-embedding method of immuno-electron microscopy (IEM) using the anti-RAP-1 monoclonal antibody (mAb) 1C1 in order to substantiate the result in our previous report by an indirect immunofluorescent antibody test and the pre-embedding method of IEM. RAP-1 slightly distributed only in cytoplasm of merozoites, especially around the nucleus, but not in the rhoptry organelle at an early stage after invasion into a red blood cell. Then, the RAP-1 was accumulated in the rhoptry organelle and was also found in the iRBC cytoplasm, which suggests that synthesis and release of RAP-1 may occur in the iRBC. Finally, the RAP-1 was found within...
Palavras-chave: Babesia bovis RAP-1 invasion; Escape RBC.
Ano: 2005
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/145

High Genetic Diversity of Anaplasma marginale Detected from Philippine Cattle
Provedor de dados: 19
Autores: Ybañez, Adrian Patalinghug; Ybañez, Rochelle Haidee D.; Claveria, Florencia G.; Cruz-Flores, Mary Jane; Xuenan, Xuen; Yokoyama, Naoaki; Inokuma, Hisashi.
A total of 658 cattle in 6 provinces in the Philippines were screened for Anaplasma marginale infection by using a diagnostic heat-shock operon (groEL) gene-PCR assay. The screening-positive samples were further tested using the major surface antigen protein 1a (Msp1a) gene-PCR assay. Screening PCR results showed 130 cattle (19.8%) were positive for the A. marginale infection. Subsequent amplification using the Msp1a gene only showed 93 samples (14.1%) to be positive. In addition, 37 tandem-repeat structures, including 20 novel structures, and 41 distinct genotypes were identified. Interestingly, multiple infections of 4 different genotypes were also observed in A. marginale-infected cattle. The present study demonstrated the prevalence and...
Palavras-chave: Anaplasma marginale; Cattle; GroEL; Msp1a; Philippines.
Ano: 2014
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4011

Molecular Prevalence of Different Genotypes of Theileria orientalis Detected from Cattle and Water Buffaloes In Thailand
Provedor de dados: 19
Autores: Altangerel, Khukhuu; Sivakumar, Thillaiampalam; Inpankaew, Tawin; Jittapalapong, Sathaporn; Terkawi, Mohamad Alaa; Ueno, Akio; Xuan, Xuenan; Igarashi, Ikuo; Yokoyama, Naoaki; 玄, 学南; 五十嵐, 郁男; 横山, 直明.
Here we report on an epidemiological study regarding the molecular prevalence of different genotypes of Theileria orientalis present among domestic cattle and water buffalo populations bred in Thailand. A phylogenetic analysis based on the parasitic gene encoding a major piroplasm surface protein revealed the presence of 5 genotypes (Types 1, 3, 5, 7, and N-3) in cattle and 7 genotypes (Types 1, 3, 4, 5, 7, N-2, and N-3) in water buffaloes. Types 4, 7, and N-3 of T. orientalis were reported for the first time in water buffaloes. The previously reported C and Thai types from Thailand clustered as types 7 and 6, respectively, in the present analysis. Great similarities were observed among nucleotide sequences of isolates of the same genotype from cattle and...
Ano: 2011
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3592

Characterization of an epimastigote-stage-specific hemoglobin receptor of Trypanosoma congolense
Provedor de dados: 19
Autores: Yamasaki, Shino; Suganuma, Keisuke; Yamagishi, Junya; Asada, Masahito; Yokoyama, Naoaki; Kawazu, Shin-ichiro; Inoue, Noboru.
Background: Since Trypanosorna spp. lack a complete heme synthesis pathway, the parasites are totally dependent on their host for heme throughout all of the stages of their life -cycle. We herein report the identification and characterization of a T. congolense epimastigote form (EMF)-specific hemoglobin (Hb) receptor. The gene was initially reported to encode a T. congolense haptoglobin (Hp)-Hb complex receptor (TcHpHbR) based on its similarity to a gene encoding a T brucei Hp-Hb complex receptor (TbHpHbR). Methods: Trypanosorna congolense IL3000 was used in this study. A TcHpHbR gene was PCR amplified from the parasite genome. The recombinant protein was used as an immunogen to raise antibodies for immunofluorescence assay and immunoblotting. Hemoglobin...
Palavras-chave: Trypanosome congolense; Epimastigote; Hemoglobin receptor.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4441

RBC invasion and invasion-inhibition assays using free merozoites isolated after cold treatment of Babesia bovis in vitro culture
Provedor de dados: 19
Autores: Ishizaki, Takahiro; Sivakumar, Thillaiampalam; Hayashida, Kyoko; Tuvshintulga, Bumduuren; Igarashi, Ikuo; Yokoyama, Naoaki.
Babesia bovis is an apicomplexan hemoprotozoan that can invade bovine red blood cells (RBCs), where it multiplies asexually. RBC invasion assays using free viable merozoites are now routinely used to understand the invasion mechanism of B. bovis, and to evaluate the efficacy of chemicals and antibodies that potentially inhibit RBC invasion by the parasite. The application of high-voltage pulses (high-voltage electroporation), a commonly used method to isolate free merozoites from infected RBCs, reduces the viability of the merozoites. Recently, a cold treatment of B. bovis in vitro culture was found to induce an effective release of merozoites from the infected RBCs. In the present study, we incubated in vitro cultures of B. bovis in an ice bath to...
Palavras-chave: Babesia bovis; Cold treatment; Invasion-inhibition assay; Merozoite isolation; RBC invasion.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4488

Multiple infections of Anaplasma platys variants in Philippine dogs
Provedor de dados: 19
Autores: Adrian Patalinghug Ybañez; Rochelle Haidee Daclan Ybañez; Yokoyama, Naoaki; Inokuma, Hisashi.
Aim: Anaplasma platys, the causative agent of infectious canine cyclic thrombocytopenia, is a tick-borne pathogen that also has been implicated as potentially zoonotic. To provide molecular evidence on the multiple infections of A. platys variants in Philippine dogs. Materials and Methods: DNA fragments of A. platys from infected dogs in the Philippines were molecularly characterized. For screening, 25 dogs suspected to have canine anaplasmosis were tested using a 16S rRNA-based nested polymerase chain reaction (PCR). Infection was confirmed by sequencing of positive amplicons. Second round PCR targeting a longer 16S rRNA fragment was subsequently performed on the first round PCR amplicons of the positive samples. Further characterization using the...
Palavras-chave: Anaplasma platys; Dogs; Philippines; Variants.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4537

In vitro inhibitory effect of fosmidomycin on the asexual growth of Babesia bovis and Babesia bigemina
Provedor de dados: 19
Autores: Sivakumar, T; Aboulaila, M. R. A.; Khukhuu, A; Iseki, H; Alhassan, A; Yokoyama, Naoaki; Igarashi, Ikuo; 横山, 直明; 五十嵐, 郁男.
The in vitro inhibitory effect of fosmidomycin was evaluated against the asexual growth of bovine Babesia parasites (Babesia bovis and Babesia bigemina). In the cultures with these parasites, severe reduction of parasite growth was observed by the addition of 1.25 μg/ml of the final drug concentration. Under these conditions, B. bigemina was completely cleared until the third day of cultivation. On the other hand, B. bovis was completely eliminated on the fourth day when the concentration was 6.25 μg/ml in the culture. These parasites failed to grow again when a drug-free medium was substituted for the subsequent cultivation. The IC50 values of fosmidomycin against B. bovis were determined as 0.88 and 0.63 μg/ml in the in vitro cultures with...
Palavras-chave: Fosmidomycin; Babesia bovis; Babesia bigemina; Asexual growth; In vitro culture.
Ano: 2008
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2235

A longitudinal study of Babesia and Theileria infections in cattle in Sri Lanka
Provedor de dados: 19
Autores: Sivakumar, Thillaiampalam; Kothalawala, Hemal; Weerasooriya, Gayani; Seekkuge Susil Priyantha Silva; Puvanendiran, Sumathy; Munkhjargal, Tserendorj; Igarashi, Ikuo; Yokoyama, Naoaki.
Throughout the world, infections with the Babesia and Theileria parasites often result in economically significant clinical disease in cattle. We conducted a longitudinal survey of Babesia and Theileria infections in cattle from the Polonnaruwa (n?=?75; dry zone) and Nuwara Eliya (n?=?161; wet zone) districts of Sri Lanka. DNA from blood samples collected in June, September, and December 2014 and March 2015 was screened for Babesia bovis, Babesia bigemina, Theileria annulata and Theileria orientalis using specific polymerase chain reactions (PCRs). Additionally, serum samples collected from the animals were screened using enzyme-linked immunosorbent assays (ELISAs) to detect B. bovis- and B. bigemina-specific antibodies. All of the animals surveyed in...
Palavras-chave: Babesia; Cattle; Longitudinal study; Sri Lanka; Theileria.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4567

CLONING AND EXPRESSION OF AN ANTIGEN OF BABESIA GIBSONI IN ESCHERICHIA COLI AND ITS USE FOR THE IMMUNODIAGNOSIS OF CANINE BABESIOSIS
Provedor de dados: 19
Autores: Fukumoto, Shinya; Sekine, Yukiko; Kimbita, Elikira; Huang, Xiaohong; Xuan, Xuenan; Inoue, Noboru; Yokoyama, Naoaki; Igarashi, Ikuo; Fujisaki, Kozo; Sugimoto, Chihiro; Nagasawa, Hideyuki; Mikami, Takeshi; Suzuki, Hiroshi; 福本, 晋也; 玄, 学南; 井上, 昇; 横山, 直明; 五十嵐, 郁男; 鈴木, 宏志.
Palavras-chave: Babesia gibsoni; Babesia canis; CDNA library; ELISA; P30 gene.
Ano: 2002
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/624

オリゴマンノース糖鎖被覆(OML)リポソームワクチン投与後の牛の免疫応答の解析
Provedor de dados: 19
Autores: 横山, 直明; Yokoyama, Naoaki.
Ano: 2008
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2184

IMMUNOSCREENING OF BABESIA RODHAINI GENES ENCODING IMMUNOGENIC PROTEINS FROM THE CDNA EXPRESSION PHAGE LIBRARY
Provedor de dados: 19
Autores: Fujii, Kei; Takabatake, Noriyuki; Boonchit, Suthisak; Hirata, Haruyuki; Yokoyama, Naoaki; Igarashi, Ikuo; 横山, 直明; 五十嵐, 郁男.
Palavras-chave: Babesia rodhaini; Babesiosis; Immunoscreening; CDNA expression library.
Ano: 2002
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/626

原虫・宿主相互細胞機能の免疫病理学的研究
Provedor de dados: 19
Autores: 横山, 直明; 五十嵐, 郁男; Yokoyama, Naoaki; Igarashi, Ikuo.
発行年は推定
Ano: 2007
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3506

Specific Molecular Detection of Anaplasma sp. Closely Related to Anaplasma phagocytophilum in Ixodid Ticks and Cattle in a Pastureland in Hokkaido, Japan
Provedor de dados: 19
Autores: Ybañez, Adrian P.; Tagawa, Michihito; Matsumoto, Kotaro; Kishimoto, Toshio; Yokoyama, Naoaki; Inokuma, Hisashi; 横山, 直明; 猪熊, 壽.
http://online.liebertpub.com/doi/abs/10.1089/vbz.2012.0963
Palavras-chave: Anaplasma sp.; Anaplasma phagocytophilum; Heat-shock operon; Ticks; Cattle.
Ano: 2013
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3834

FUCOIDAN INHIBITS THE IN VITRO GROWTH OF BABESIA BOVIS
Provedor de dados: 19
Autores: Takabatake, Noriyuki; Hashiba, Shintaro; Bork, Sabine; Okamura, Masashi; Yokoyama, Naoaki; Igarashi, Ikuo; 横山, 直明; 五十嵐, 郁男.
Palavras-chave: Babesia bovis; Fucoidan.
Ano: 2004
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/646

CURRENT SERODIAGNOSTIC MEASURES FOR EQUINE BABESIOSIS
Provedor de dados: 19
Autores: Hirata, Haruyuki; Yokoyama, Naoaki; Xuan, Xuenan; Igarashi, Ikuo; 横山, 直明; 玄, 学南; 五十嵐, 郁男.
Palavras-chave: Babesia equi; Babesia caballi; Diagnosis; ELISA; ICT.
Ano: 2004
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/638

Neospora caninum: Application of apical membrane antigen 1 encapsulated in the oligomannose-coated liposomes for reduction of offspring mortality from infection in BALB/c mice
Provedor de dados: 19
Autores: Zhang, Houshuang; Nishikawa, Yoshifumi; Ikehara, Yuzuru; Kojima, Naoya; Yokoyama, Naoaki; Xuan, Xuenan.
Liposomes coated with neoglycolipids constructed with mannopentaose and  dipalmitoylphosphatidylethanolamine (Man3-DPPE), referred to as M3-DPPE  liposomes, have been shown to induce cellular immunity against antigens encapsulated therein. To evaluate whether these M3-DPPE liposomes have an  adjuvant capacity against Neospora caninum infection, a novel immunization  method utilizing soluble N. caninum apical membrane antigen 1 (NcAMA1)  encapsulated in the M3-DPPE liposomes (M3-NcAMA1) was employed. The  intent was to reduce offspring mortality from N. caninum infection in susceptible,  pregnant BALB/c mice. The results revealed that BALB/c mice developed IgG  antibodies specific to N. caninum. A significant amount of interferon (IFN)-γ  production was...
Palavras-chave: Neospora caninum; Apical membrane antigen 1; Oligomannose-coated liposomes.
Ano: 2010
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2821

Babesia ovata: Taxonomy, phylogeny and epidemiology
Provedor de dados: 19
Autores: Sivakumar, Thillaiampalam; Igarashi, Ikuo; Yokoyama, Naoaki.
Babesia ovata, which is transmitted by Haemaphysalis longicornis, is an intraerythrocytic protozoan parasite of cattle. Based on its morphology, B. ovata is classified as a large-type Babesia. The developmental stages of B. ovata have been described both in cattle and the tick vector. In infected adult female ticks, the parasite is transovarially transmitted to the tick eggs. The sexual reproduction of B. ovata has been demonstrated in the tick midgut. The diagnostic tools that are currently available for the specific detection of B. ovata in cattle include microscopy and polymerase chain reaction assays. The development of improved molecular and serological diagnostic tools has been constrained by the limited availability of genetic data. B. ovata has...
Palavras-chave: Babesia ovata; Cattle; Epidemiology; Phylogeny; Taxonomy.
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4555

The PCR detection and phylogenetic characterization of Babesia microti in questing ticks in Mongolia
Provedor de dados: 19
Autores: Tuvshintulga, Bumduuren; Sivakumar, Thillaiampalam; Battsetseg, Badgar; Narantsatsaral, Sandag-ochir; Enkhtaivan, Batsaikhan; Battur, Banzragch; Hayashida, Kyoko; Okubo, Kazuhiro; Ishizaki, Takahiro; Inoue, Noboru; Igarashi, Ikuo; Yokoyama, Naoaki.
Babesia microti is a tick-transmitted zoonotic hemoprotozoan parasite. In the present study, we investigated B. microti infection in questing ticks in Mongolia. A total of 219 questing ticks were collected from three different Mongolian provinces (Bayan-Olgii, Khovsgol, and Selenge). Of these, 63 from Selenge were identified as Ixodes persulcatus, while the remaining 156 (from all three provinces) were identified as Dermacentor nuttalli. When the tick DNA samples were screened using a B. microti-specific nested PCR, 19 (30.2%) of the 63 I. persulcatus ticks were found to be B. microti-positive. The parasite was not detected in D. nuttalli. Subsequently, the 18S rRNA, cox1, and tufA sequences of B. microti were amplified, sequenced, and subjected to...
Palavras-chave: 18S rRNA; B. microti; Cox1; Mongolia; Ticks; TufA.
Ano: 2015
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4554

Protective immunity of blood plasma fraction containing Babesia rodhaini exoantigens in mice
Provedor de dados: 19
Autores: Kamiya, Shiho; Takabatake, Noriyuki; Fujii, Kei; Okamura, Masashi; Iseki, Hiroshi; Yokoyama, Naoaki; Igarashi, Ikuo.
Babesia spp. are major hemoprotozoan parasites in animals. Exoantigens, which are soluble antigens released by the parasites during their asexual development, have been successfully applied for the development of a vaccine against babesiosis. In this study, we examined the ability of exoantigens to induce protective immunity in mice against a rodent Babesia parasite, Babesia rodhaini. The BALB/c mice immunized with the blood plasma fraction of B. rodhaini-infected mice (B. rodhaini exoantigens) showed a significant decrease in the lethal rate when challenged with B. rodhaini. Western blot analysis with anti-B. rodhaini exoantigen immune serum specifically detected at least eleven proteins in the lysate of B. rodhaini-infected erythrocytes. Next, a cDNA...
Palavras-chave: Babesiosis; Babesia rodhaini; Exoantigen; Protective effect; Mice.
Ano: 2005
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/149

Babesia bovis: Subcellular localization of host erythrocyte membrane components during their asexual growth
Provedor de dados: 19
Autores: Okamura, Masashi; Yokoyama, Naoaki; Takabatake, Noriyuki; Okubo, Kazuhiro; Ikehara, Yuzuru; Igarashi, Ikuo; 横山, 直明; 五十嵐, 郁男.
In the present study, the subcellular localization of the host red blood cell (RBC) membrane components, the alpha 2-3-linked sialic acid (SA) residues and the lipid bilayer, was observed during the asexual growth of Babesia bovis using two erythrocyte probes, the SA-specific lectin (MALII) and the lipophilic fluorescent (PKH2) probes, respectively. In confocal laser scanning microscopy with MALII, the SA residues on the surface of parasitized RBCs appeared to accumulate into the intracellular parasites as the parasites matured as well as to remain on the surface of extracellular parasites. Furthermore, when PKH2-labeled RBCs were infected with B. bovis, PKH2 signals were also observed around both the intracellular and the extracellular parasites,...
Palavras-chave: Babesia bovis (B. bouis); SA; MALII; RBC; RT; PBS; Babesia equi (B. equi); PV.
Ano: 2007
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/1040

Toxoplasma gondii Infection in Mice Impairs Long-Term Fear Memory Consolidation through Dysfunction of the Cortex and Amygdala
Provedor de dados: 19
Autores: Ihara, Fumiaki; Nishimura, Maki; Muroi, Yoshikage; Mahmoud, Motamed Elsayed; Yokoyama, Naoaki; Nagamune, Kisaburo; Nishikawa, Yoshifumi.
Chronic infection with Toxoplasma gondii becomes established in tissues of the central nervous system, where parasites may directly or indirectly modulate neuronal function. Epidemiological studies have revealed that chronic infection in humans is a risk factor for developing mental diseases. However, the mechanisms underlying parasite-induced neuronal dysfunction in the brain remain unclear. Here, we examined memory associated with conditioned fear in mice and found that T. gondii infection impairs consolidation of conditioned fear memory. To examine the brain pathology induced by T. gondii infection, we analyzed the parasite load and histopathological changes. T. gondii infects all brain areas, yet the cortex exhibits more severe tissue damage than other...
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4480

Changes in neurotransmitter levels and expression of immediate early genes in brain of mice infected with Neospora caninum
Provedor de dados: 19
Autores: Ihara, Fumiaki; Nishimura, Maki; Muroi, Yoshikage; Furuoka, Hidefumi; Yokoyama, Naoaki; Nishikawa, Yoshifumi.
Neospora caninum is an obligate intracellular parasite that causes neurological disorders in dogs and cattle. The majority of host animals are asymptomatic at the chronic stage of infection. However, it remains unclear whether cerebral function is normal in asymptomatic animals. In this study, mice were infected with N. caninum (strain Nc-1) and their brains were examined to understand changes in cerebral function at the chronic stage of infection. Mice infected with N. caninum showed impaired locomotor activity, but no differences in clinical symptoms were observed. In the brains of infected mice, parasites were distributed throughout the brain and histological lesions were observed everywhere except for the cerebellum. Expression levels of...
Ano: 2016
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4460

Inhibitory Effects of Pepstatin A and Mefloquine on the Growth of Babesia Parasites
Provedor de dados: 19
Autores: Munkhjargal, Tserendorj; AbouLaila, Mahmoud; Mohamad Alaa Terkawi; Sivakumar, Thillaiampalam; Ichikawa, Madoka; Davaasuren, Batdorj; Nyamjargal, Tserendorj; Yokoyama, Naoaki; Igarashi, Ikuo; 横山, 直明; 五十嵐, 郁男.
We evaluated the inhibitory effects of pepstatin A and mefloquine on the in vitro and in vivo growths of Babesia parasites. The in vitro growth of Babesia bovis, B. bigemina, B. caballi, and B. equi was significantly inhibited (P &lt; 0.05) by micromolar concentrations of pepstatin A (50% inhibitory concentrations = 38.5, 36.5, 17.6, and 18.1 μM, respectively) and mefloquine (50% inhibitory concentrations = 59.7, 56.7, 20.7, and 4 μM, respectively). Furthermore, both reagents either alone at a concentration of 5 mg/kg or in combinations (2.5/2.5 and 5/5 mg/kg) for 10 days significantly inhibited the in vivo growth of B. microti in mice. Mefloquine treatment was highly effective and the combination treatments were less effective than other treatments....
Ano: 2012
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3829

Babesia bovis: Effects of cysteine protease inhibitors on in vitro growth
Provedor de dados: 19
Autores: Okubo, Kazuhiro; Yokoyama, Naoaki; Govind, Yadav; Alhassan, Andy; Igarashi, Ikuo.
In the present study, we examined the effects of four kinds of cysteine protease inhibitors (E64, E64d, leupeptin, and ALLN) on the in vitro asexual growth of Babesia bovis. Of these, only the lipophilic inhibitors, E64d and ALLN, were found to effectively inhibit the growth of B. bovis. In further experiments, E64d, but not ALLN, significantly suppressed the parasite’s invasion of host erythrocytes, while both chemicals, especially ALLN, inhibited the parasite’s replication within the infected erythrocytes. These data suggested the presence of cysteine protease(s) derived from B. bovis, in which the protease(s) would play important roles in the erythrocyte invasion and/or replication processes of the parasite.
Palavras-chave: Babesia bovis; Cysteine protease; Inhibitor; Invasion; Replication.
Ano: 2007
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/1041