Yoshifumi Nishikawa

Obihiro University of Agriculture and Veterinary Medicine, Obibiro, Hokkaidō, Japan

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Publications (183)371.48 Total impact

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    ABSTRACT: In the current study, we examined the effects of phagocytes depletion on the progression of Plasmodium yoelii -17XNL infection in mice. Strikingly, the depletion of phagocytic cells, including macrophages with clodronate in the acute-phase of infection significantly reduced peripheral parasitemia but increased mortality. Moribund mice displayed severe pathological damages included coagulative necrosis in liver and thrombi in the glomeruli, fibrin deposition, and tubulonecrosis in kidney. The severity of infection was coincident with the increased sequestration of parasitized erythrocytes, the systematic upregulation of inflammation and coagulation, and the disruption of endothelial integrity in the liver and kidney. Aspirin was administered to the mice to minimize the risk of excessive activation of the coagulation response and fibrin deposition in the renal tissue. Interestingly, treatment with aspirin reduced the parasite burden and pathological lesions in the renal tissue and improved survival of phagocyte-depleted mice. Our data imply that the depletion of phagocytic cells, including macrophages in the acute-phase of infection increases the severity of malarial infection, typified by multiorgan failure and high mortality.
    No preview · Article · Jan 2016 · Infection and Immunity
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    ABSTRACT: The glyoxalase pathway, which includes two enzymes, glyoxalase 1 and 2 (Glo1 and Glo2), is a ubiquitous cellular system responsible for the removal of cytotoxic methylglyoxal produced during glycolysis. Protozoan parasites, including Toxoplasma gondii (T. gondii) tachyzoites, produce methylglyoxal because of increased glycolytic fluxes. A Glo1 inhibitor such as curcumin could be considered a drug candidate for anti-protozoan, anti-inflammatory, and anti-cancer therapy. The T. gondii Glo1 gene (TgGlo1) was cloned and the recombinant protein was produced. Enzyme kinetics of TgGlo1 and five mutants were evaluated by adding methylglyoxal and glutathione to a reaction mixture. Finally, the inhibitory effects of various concentrations of curcumin on recombinant TgGlo1 were evaluated using in vitro cultures of T. gondii. Active recombinant TgGlo1 was successfully produced and the active sites (E166 and E251) of TgGlo1 were verified by point mutagenesis. Curcumin at the tested doses inhibited the enzymatic activity of recombinant TgGlo1 as well as the parasitic propagation of in vitro-cultured T. gondii. The K i and IC 50 were 12.9 ± 0.5 μM and 38.3 ± 0.9 μM, respectively. The inhibitory effect of curcumin on the enzymatic activity of TgGlo1 and parasitic propagation of T. gondii could be explored in the potential development of a potent drug for the treatment of toxoplasmosis. However, considering the fact that curcumin is known to have many effects on other molecules in the micromolar range, further elucidation of curcumin’s direct inhibition of the glyoxalase system of T. gondii will be needed.
    Full-text · Article · Dec 2015 · Parasites & Vectors
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    ABSTRACT: Although Toxoplasma gondii (T. gondii) infection is relevant to many psychiatric disorders, the fundamental mechanisms of its neurobiological correlation with depression are poorly understood. Here, we show that reactivation of chronic infection by an immunosuppressive regimen caused induction of depressive-like behaviors without obvious sickness symptoms. However, the depression-related behaviors in T. gondii-infected mice, specifically, reduced sucrose preference and increased immobility in the forced-swim test were observed at the reactivation stage, but not in the chronic infection. Interestingly, reactivation of T. gondii was associated with production of interferon-gamma and activation of brain indoleamine 2, 3-dioxygenase, which converts tryptophan to kynurenine and makes it unavailable for serotonin synthesis. Furthermore, serotonin turnover to its major metabolite, 5-hydroxyindoleacetic acid, was also enhanced at the reactivation stage. Thus, enhanced tryptophan catabolic shunt and serotonin turnover may be implicated in development of depressive-like behaviors in mice with reactivated T. gondii.
    Full-text · Article · Nov 2015 · Behavioural brain research
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    Full-text · Dataset · Oct 2015
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    Full-text · Dataset · Oct 2015
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    ABSTRACT: We show that Cryptosporidium parvum virus 1 (CSpV1), a member of the family Partitiviridae, genus Cryspovirus that can infect Cryptosporidium parvum, is a new candidate for high-resolution tool for tracing Cryptosporidium parvum. CSpV1 was detected in all C. parvum-positive samples tested. Phylogenetic analysis of dsRNA1 sequence from CSpV1 can distinguish infected areas of C. parvum on the national level. Sequences detected in samples from Iwate prefecture and other islands (Tanegashima, and Okinawa) belonged to a single clade. This system can differentiate the samples from Hokkaido and south part of Japan as well as from other countries. Samples from Iwate, Tanegashima, and Okinawa belonged to a single subclade respectively. Therefore, the CSpV1 dsRNA sequences reflect the regional distribution of their host and have potential as a high-resolution tool to trace C. parvum IIaA15G2R1 subtype.
    No preview · Article · Oct 2015 · Virus Research
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    Buyannemekh Tumurjav · Yoshifumi Nishikawa · Xuenan Xuen
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    ABSTRACT: The seroprevalence of T. gondii infection in Mongolian sheep was investigated using an ELISA with rTgMAG1. A total of 175 serum samples collected from seven aimags in Mongolia were examined by an ELISA, and the results were compared with those from the commercialized LAT. Although, both tests showed high concordance, the ELISA detected 24% of infection and it seems to be more sensitive than the LAT detected 16.5% of infection in ovine samples. These results emphasize the usefulness of rTgMAG1 for diagnostic use in detection of T. gondii infection.Mongolian Journal of Agricultural Sciences Vol.15(2) 2015; 33-37
    Preview · Article · Sep 2015
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    ABSTRACT: Toxoplasma gondii infection can be diagnosed directly by polymerase chain reaction (PCR), hybridization and isolation of parasites and indirectly with serological methods[4; 5; 18].Although all these tests have shortcomings, serological tests, particularly the enzyme-linked immunosorbent assay (ELISA), seem to be the most practical and economical. The crude antigen prepared from tachyzoites has been traditionally utilized for commercially serological detection kits. However the use of recombinant antigens can be alternative sources of antigens allowing better standardization of the tests and reducing the costs of production requires mass production of the parasite either from the peritoneal fluids of infected mice or from tissue cultures. In spite of the potential advantages of using recombinant antigens in serology tests, their sensitivities have not yet achieved perfect result; therefore, further research on new antigensis extremely desirable [10; 16; 17; 3]. In this context, the Toxoplasma gondii matrix antigen 1 (TgMAG1) known as 65-kDa protein abundantly expressed within the cyst and in the cyst wall surrounding the bradyzoites [15], has documented to be immunogenic during the infection with T. gondii in mouse model and promising reagent for serodiagnosis of toxoplasmosis in humans [15;12; 6]. However, its usefulness has not yet been confirmed in animal toxoplasmosis.In this study, the optimization and validation of E.coli-expressed rTgMAG1as ELISA antigen were describedMongolian Journal of Agricultural Sciences Vol.15(2) 2015; 56-60
    Preview · Article · Sep 2015
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    ABSTRACT: Lysophospholipids are important signaling molecules in animals and metazoan cells. They are widely distributed among marine invertebrates, where their physiological roles are unknown. Sea cucumbers produce unique lysophospholipids. In this study, two lysophospholipids were detected in Holothuria atra for the first time, lyso-platelet activating factor and lysophosphatidylcholine, with nuclear magnetic resonance and liquid chromatography-time-of-flight mass spectrometric analyses. The lipid fraction of H. atra contained lyso-platelet activating factor and lysophosphatidylcholine, and inhibited H2O2-induced apoptosis in the macrophage cell line J774A.1. The antioxidant activity of the lysophospholipid-containing lipid fraction of H. atra was confirmed with the oxygen radical absorbance capacity method. Our results suggest that the lysophospholipids from H. atra are potential therapeutic agents for the inflammation induced by oxidative stress.
    Preview · Article · Aug 2015 · PLoS ONE
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    ABSTRACT: Neospora caninum can cause fetal abortion and neonatal mortality in cattle, and is a cause of economic concern worldwide. This study aimed to determine the prevalence of Neospora caninum-specific antibodies in cattle from Western Java, Indonesia. Serum samples from 991 cattle from 21 locations were tested for antibodies to N. caninum by using an enzyme-linked immunosorbent assay (ELISA) on the basis of recombinant NcSAG1. The overall seroprevalence was 16.6%, ranging from 0 to 87.5% in the sampled locations. The results of this study indicate latent infection rates of sampled animals were different in each location. Further studies are necessary to elucidate the relationship between N. caninum infection and abortion in cattle, and to identify risk factors for infection in high-prevalence environments.
    Full-text · Article · Aug 2015 · Journal of Veterinary Medical Science
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    ABSTRACT: Toxoplasmosis is a concern in both human and veterinary medicine, and the consumption of undercooked meat infected with T. gondii is a major risk factor in human infection. Establishing the prevalence of the parasite in food-producing livestock is essential to reduce the risk of human infection. This study aimed to determine the prevalence of T. gondii-specific antibodies in cattle and pigs in Western Java, Indonesia. Serum samples from 598 cattle and 205 pigs from 18 locations in Western Java, Indonesia, were tested for antibodies to Toxoplasma gondii using an enzyme-linked immunosorbent assay (ELISA). The seroprevalence was 14.6% in pigs and 7.4% in cattle, and significantly more pigs were seropositive compared with cattle (p<0.01). The results of this study suggest that consumption of undercooked meat should be regarded as an important source of infection in people. This study suggests that the risk factors for T. gondii infection in livestock appeared to be different in each location because geographical variation in seroprevalence was observed. The results of this study will facilitate further research to identify and control risk factors for T. gondii in the surveyed locations. Copyright © 2015. Published by Elsevier Ireland Ltd.
    Full-text · Article · Jul 2015 · Parasitology International
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    ABSTRACT: The M17 leucine aminopeptidase (M17LAP) enzymes of the other apicomplexan parasites have been characterized and shown to be inhibited by bestatin. Though Babesia bovis also belong to the apicomplexan group, it is not known whether its M17LAP could display a similar biochemical properties as well as inhibition profile. To unravel this uncertainty, a B. bovis M17LAP (BbM17LAP) gene was expressed in Escherichia coli, and activity of the recombinant enzyme as well as its inhibition by bestatin were evaluated. The inhibitory effect of the compound on growths of B. bovis and B. gibsoni in vitro was also determined. The expression of the gene fused with glutathione S-transferase (GST) yielded approximately 81-kDa recombinant BbM17LAP (rBbM17LAP). On probing with mouse anti-rBbM17LAP serum, a green fluorescence was observed on the parasite cytosol on confocal laser microscopy and specific band greater than predicted molecular mass was seen on Western blotting. The Km and Vmax values of the recombinant enzyme were 139.3 ± 30.25 and 64.83± 4.6 µM, respectively while the Ki was 2210 ± 358 μM after the inhibition. Bestatin was a more potent inhibitor of the growth of B. bovis [IC50 = 131.7 ± 51.43 μM] than B. gibsoni [IC50 = 460.8 ± 114.45 μM] in vitro. The modest inhibition of both the rBbM17LAP activity and Babesia parasites growths in vitro suggest that this inhibition may involve the endogenous enzyme in live parasite. Therefore, BbM17LAP may be a target of bestatin though more studies with other aminopeptidase inhibitors are required to confirm this.
    No preview · Article · Jun 2015 · Journal of Parasitology
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    ABSTRACT: Cryptosporidium oocysts were found in 43 out of 77 calves from two farms in Iwate Prefecture and nine farms on Tanegashima Island, Kagoshima Prefecture, Japan. The DNA fragments of 18S ribosomal RNA (18S rRNA) gene were amplified by a nested PCR from 43 oocyst-positive as well as one oocyst-negative samples. All of them were precisely identified as C. parvum by analyzing the nucleotide sequences of the 18S rRNA gene. C. parvum oocyst-positive calves ranged in age from 6 to 13 days old and significantly have watery diarrhea (P<0.05). Sequences of the gene encoding the 60-kDa glycoprotein (GP60) in 43 Cryptosporidium oocyst-positive samples were identical to that of the zoonotic IIaA15G2R1 subtype. We therefore suggest that calves could be potential sources of C. parvum infections in humans.
    Preview · Article · Mar 2015 · Journal of Veterinary Medical Science
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    ABSTRACT: The apical complex of Toxoplasma gondii enables it to invade virtually all nucleated cells in warm-blooded animals, including humans, making it a parasite of global importance. Anti-T. gondii cellular defense mechanisms depend largely on interferon (IFN)-γ production by immune cells. However, the molecular mechanism of IFN-β-mediated defense remains largely unclear. Here, mouse peritoneal macrophages and murine embryonic fibroblasts (MEFs) primed with recombinant IFN-β and IFN-γ showed different pathways of activation. Treatment of these cells with IFN-β or IFN-γ inhibited T. gondii (Type II PLK strain) growth. Priming macrophages with IFN-β had no effect on inflammatory cytokine expression, inducible nitric oxide synthase or indoleamine 2,3-dioxygenase, nor did it have an effect on their metabolites, nitric oxide and kynurenine, respectively. In contrast, IFN-γ stimulation was characterized by classical macrophage activation and T. gondii elimination. IFN-β activation recruited the immunity-related GTPase M1 (IRGM1) to the parasitophorous vacuole in the macrophages and MEFs. Anti-toxoplasma activities induced by IFN-β were significantly reduced after IRGM1 knockdown in murine macrophages and in IRGM1 deficient MEFs. Thus, this study unravels an alternative pathway of macrophage activation by IFN-β and provides a mechanistic explanation for the contribution of IRGM1 induced by IFN-β to the elimination of T. gondii.
    Full-text · Article · Jan 2015 · Cellular Microbiology
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    ABSTRACT: The previous release of our Full-parasites database (http://fullmal.hgc.jp/) brought enhanced functionality, an expanded full-length cDNA content, and new RNA-Seq datasets from several important apicomplexan parasites. The 2015 update witnesses the major shift in the databases content with focus on diverse transcriptomes of the apicomplexan parasites. The content of the database was substantially enriched with transcriptome information for new apicomplexan parasites. The latest version covers a total of 17 species, with addition of our newly generated RNA-Seq data of a total of 909 150 388 tags. Moreover, we have generated and included two novel and unique datasets, which represent diverse nature of transcriptomes in individual parasites in vivo and in vitro. One is the data collected from 116 Indonesian patients infected with Plasmodium falciparum. The other is a series of transcriptome data collected from a total of 38 single cells of P. falciparum cultured in vitro. We believe that with the recent advances our database becomes an even better resource and a unique platform in the analysis of apicomplexan parasites and their interaction with their hosts. To adequately reflect the recent modifications and the current content we have changed the database name to DB-AT—DataBase of Apicomplexa Transcriptomes.
    Full-text · Article · Jan 2015 · Nucleic Acids Research
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    ABSTRACT: Neospora caninum is a protozoan parasite that causes neurological disorders in dogs and cattle. It can cause nonsuppurative meningoencephalitis and a variety of neuronal symptoms are observed, particularly in dogs. However, the pathogenic mechanism, including the relationship between the parasite distribution and the clinical signs, is unclear. In this study, to understand the pathogenic mechanism of neosporosis, parasite distribution and lesions were assessed in the brain of mice infected with N. caninum (strain Nc-1). Host gene expression was also analyzed with RNA sequencing (RNA-Seq). The histopathological lesions in the frontal lobe and the medulla oblongata were significantly more severe in symptomatic mice than in asymptomatic mice, although no association between the severity of the lesions and parasite numbers was found. In infected mice, the expression of 772 mouse brain genes was upregulated. A GOstat analysis predicted that the upregulated genes were involved in the host immune response. Genes whose expression correlated positively and negatively with parasite numbers were involved in the host immune response, and neuronal morphogenesis and lipid metabolic processes, respectively. These results suggest that changes in the gene expression profile associated with neuronal functions as well as immune responses can contribute to the pathogenesis in N. caninum-infected animals.
    Preview · Article · Jan 2015 · Scientific Reports
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    Chisa Abe · Sachi Tanaka · Maki Nishimura · Fumiaki Ihara · Xuenan Xuan · Yoshifumi Nishikawa
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    ABSTRACT: Background Neospora caninum, a Toxoplasma gondii-like obligate intracellular parasite, causes abortion in cattle and neurological signs in canines. To understand neosporosis better, studies on host cell migration and host immune responses during the early phase of infection are important. Although the C-C chemokine receptor 5 (CCR5) plays a crucial role in immune cell migration, the role played by it in protective immunity against N. caninum is poorly understood.MethodsCCR5¿/¿ mice were used to investigate their sensitivity levels to N. caninum infection and their ability to activate immune cells against this parasite.ResultsIncreased mortality and neurological impairment were observed in the N. caninum-infected CCR5¿/¿ mice. In comparison with wild-type mice, CCR5¿/¿ mice experienced poor migration of dendritic cells and natural killer T cells to the site of infection. Dendritic cells in an in vitro culture from CCR5¿/¿ mice could not be activated upon infection with N. caninum. Furthermore, higher levels of IFN-¿ and CCL5 expression, which are associated with brain tissue damage, were observed in the brain tissue of CCR5¿/¿ mice during the acute phase of the infection, while there was no significant difference in the parasite load between the wild-type and CCR5¿/¿ animals. Additionally, a primary microglia culture from CCR5¿/¿ mice showed lower levels of IL-6 and IL-12 production against N. caninum parasites.Conclusions Our findings show that migration and activation of immune cells via CCR5 is required for controlling N. caninum parasites during the early phase of the infection.
    Full-text · Article · Jan 2015 · Parasites & Vectors
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    ABSTRACT: Infectious diarrhea is the most frequent cause of morbidity and mortality in neonatal calves. Cryptosporidium parvum is one of the main pathogens associated with calf diarrhea. Although diarrhea is a symptom of infection with various pathogens, investigations to detect the types of pathogens have never been performed in Japan. This study investigated the prevalence of four major diarrhea-causing pathogens in calves: C. parvum, rotavirus, coronavirus, and enterotoxigenic Escherichia coli (E. coli K99). Commercial immunochromatography testing of all four pathogens and molecular analysis of C. parvum with diarrhea in calves from southernmost Okinawa and northernmost Hokkaido, Japan, were conducted. The frequencies of C. parvum, rotavirus, coronavirus, and E. coli (K99) in Okinawa were 50%, 28%, 2.3%, and 4.7%, respectively. Watery fecal stools were significantly correlated with C. parvum (p<0.05). In oocyst calculations for C. parvum, no significant difference was observed between the single-infection cases and the mixed-infection cases with rotavirus. Interestingly, molecular analyses targeting small subunit ribosomal RNA as well as glycoprotein 60 (GP60) genes revealed that the C. parvum nucleotide sequences from the two prefectures were identical, indicating that C. parvum with a uniform characteristic is distributed throughout Japan. GP60 subtyping analysis identified C. parvum from Okinawa and Hokkaido as belonging to the IIaA15G2R1 subtype, a known zoonotic subtype. Hence, control of cryptosporidiosis is important not only for pre-weaned calves, but also for human health. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    No preview · Article · Dec 2014 · Parasitology International
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    ABSTRACT: The previous release of our Full-parasites database (http://fullmal.hgc.jp/) brought enhanced functionality, an expanded full-length cDNA content, and new RNA-Seq datasets from several important apicomplexan parasites. The 2015 update witnesses the major shift in the databases content with focus on diverse transcriptomes of the apicomplexan parasites. The content of the database was substantially enriched with transcriptome information for new apicomplexan parasites. The latest version covers a total of 17 species, with addition of our newly generated RNA-Seq data of a total of 909 150 388 tags. Moreover, we have generated and included two novel and unique datasets, which represent diverse nature of transcriptomes in individual parasites in vivo and in vitro. One is the data collected from 116 Indonesian patients infected with Plasmodium falciparum. The other is a series of transcriptome data collected from a total of 38 single cells of P. falciparum cultured in vitro. We believe that with the recent advances our database becomes an even better resource and a unique platform in the analysis of apicomplexan parasites and their interaction with their hosts. To adequately reflect the recent modifications and the current content we have changed the database name to DB-AT-DataBase of Apicomplexa Transcriptomes. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.
    Full-text · Article · Nov 2014 · Nucleic Acids Research
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    ABSTRACT: Background The design and development of an effective malaria vaccine against the pre-erythrocytic and erythrocytic-stages of infection present a great challenge. Methods In the present study, protective efficacy of oligomannose-coated liposome (OML)-entrapped merozoite and sporozoite antigens against Plasmodium berghei challenge infection in BALB/c mice was evaluated. Results Subcutaneous immunization with truncated merozoite surface protein 1 entrapped with OML (OML-PbMSP1) prolonged survival, but failed to protect the mice from erythrocytic-stage infection, despite the antigen-specific antibody responses induced by the immunization regimen. In contrast, immunization with circumsporozoite protein entrapped with OML (OML-PbCSP) elicited antigen-specific humoral and cellular responses, which correlated with substantial protection against sporozoite challenge infections. Conclusions The current results represent the use of an oligomannose-coated liposome-based vaccine against pre-erythrocytic and erythrocytic stages malaria infection. This approach may offer a new vaccination strategy against malaria infection.
    Full-text · Article · Nov 2014 · Malaria Journal

Publication Stats

2k Citations
371.48 Total Impact Points

Institutions

  • 2000-2015
    • Obihiro University of Agriculture and Veterinary Medicine
      • National Research Center for Protozoan Diseases
      Obibiro, Hokkaidō, Japan
  • 2004
    • Yale-New Haven Hospital
      New Haven, Connecticut, United States
  • 1998-2002
    • The University of Tokyo
      • Department of Global Agricultural Sciences
      Edo, Tōkyō, Japan
  • 2001
    • Chiang Mai University
      Amphoe Muang Chiang Mai, Chiang Mai, Thailand