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| Kato, Kentaro; Sugi, Tatsuki; Takemae, Hitoshi; Takano, Ryo; Gong, Haiyan; Ishiwa, Akiko; Horimoto, Taisuke; Akashi, Hiroomi. |
| Background: Toxoplasma gondii is an obligate intracellular parasite of the phylum Apicomplexa and a major pathogen of animals and immunocompromised humans, in whom it causes encephalitis. Understanding the mechanism of tachyzoite invasion is important for the discovery of new drug targets and may serve as a model for the study of other apicomplexan parasites. We previously showed that Plasmodium falciparum expresses a homolog of human calcium calmodulin-dependent protein kinase (CaMK) that is important for host cell invasion. In this study, to identify novel targets for the treatment of Toxoplasma gondii infection (another apicomplexan parasite), we sought to identify a CaMK-like protein in the T. gondii genome and to characterize its role in the... |
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Palavras-chave: Calcium calmodulin-dependent protein kinase homolog; GAP45; Phosphorylation; T. gondii CaMK-related kinase; Toxoplasma gondii. |
| Ano: 2016 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4447 |
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| Kato, Kentaro; Murata, Yuho; Horiuchi, Noriyuki; Inomata, Atsuko; Terkawi, Mohamad Alaa; Ishiwa, Akiko; Ogawa, Yohsuke; Fukumoto, Shinya; Matsuhisa, Fumikazu; Koyama, Kenji. |
| Background: Toxoplasma gondii is a highly prevalent protozoan that can infect all warm-blooded animals, including humans. Its definitive hosts are Felidae and its intermediate hosts include various other mammals and birds, including pigs. It is found in the meat of livestock which is a major source of human infection. Hence the control of toxoplasmosis in pigs is important for public health. We previously showed that dextran sulfate (DS), especially DS10 (dextran sulfate MW 10 kDa), is effective against T. gondii infection both in vitro and in mice. In this study, we asked whether DS affects T. gondii infection of pigs, one of the main animal sources of toxoplasmosis transmission to humans. Methods: Fourteen-day-old male pigs (n = 10) were infected with T.... |
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Palavras-chave: Dextran sulfate; Intermediate host; Pig; Public health; Toxoplasma gondii. |
| Ano: 2016 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4446 |
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| Murata, Yuho; Sugi, Tatsuki; Weiss, Louis M.; Kato, Kentaro. |
| Drug treatment for toxoplasmosis is problematic, because current drugs cannot eradicate latent infection with Toxoplasma gondii and can cause bone marrow toxicity. Because latent infection remains after treatment, relapse of infection is a problem in both infections in immunocompromised patients and in congenitally infected patients. To identify lead compounds for novel drugs against Toxoplasma gondii, we screened a chemical compound library for anti-Toxoplasma activity, host cell cytotoxicity, and effect on bradyzoites. Of 878 compounds screened, 83 demonstrated > 90% parasite growth inhibition. After excluding compounds that affected host cell viability, we further characterized two compounds, tanshinone IIA and hydroxyzine, which had IC50 values for... |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4449 |
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| Adeyemi, Oluyomi Stephen; Murata, Yuho; Sugi, Tatsuki; Kato, Kentaro. |
| This study evaluated the anti-Toxoplasma gondii potential of gold, silver, and platinum nanoparticles (NPs). Inorganic NPs (0.01-1,000 mu g/mL) were screened for antiparasitic activity. The NPs caused >90% inhibition of T. gondii growth with EC50 values of <= 7, <= 1, and <= 100 mu g/mL for gold, silver, and platinum NPs, respectively. The NPs showed no host cell cytotoxicity at the effective anti-T. gondii concentrations; the estimated selectivity index revealed a >= 20-fold activity toward the parasite versus the host cell. The anti-T. gondii activity of the NPs, which may be linked to redox signaling, affected the parasite mitochondrial membrane potential and parasite invasion, replication, recovery, and infectivity potential. Our results... |
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Palavras-chave: Antiparasite; Drug screening; Nanomedicine; Toxoplasmosis. |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4450 |
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| Terkawi, Mohamad Alaa; Takano, Ryo; Furukawa, Atsushi; Murakoshi, Fumi; Kato, Kentaro. |
| Understanding the molecular defense mechanism of macrophages and identifying their effector molecules against malarial parasites may provide important clues for the discovery of new therapies. To analyze the immunological responses of malarial parasite-induced macrophages, we used DNA microarray technology to examine the gene profile of differentiated macrophages phagocytizing Plasmodium falciparum-parasitized erythrocytes (iRBC). The transcriptional gene profile of macrophages in response to iRBCs represented 168 down-regulated genes, which were mainly involved in the cellular immune response, and 216 upregulated genes, which were involved in cellular proteolysis, growth, and adhesion. Importantly, the specific upregulation of beta-defensin 130 (DEFB130)... |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4448 |
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| Adeyemi, Oluyomi Stephen; Murata, Yuho; Sugi, Tatsuki; Han, Yongmei; Kato, Kentaro. |
| Background Toxoplasmosis constitutes a large global burden that is further exacerbated by the shortcomings of available therapeutic options, thus underscoring the urgent need for better anti-Toxoplasma gondii therapy or strategies. Recently, we showed that the anti-parasitic action of inorganic nanoparticles (NPs) could, in part, be due to changes in redox status as well as in the parasite mitochondrial membrane potential. Methods In the present study, we explored the in vitro mode of action of the anti-T. gondii effect of NPs by evaluating the contributions of host cellular processes, including the tryptophan pathway and hypoxia-inducing factor activity. NPs, at concentrations ranging from 0.01 to 200 μg/ml were screened for anti-parasitic activity.... |
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Palavras-chave: Hypoxia Indoleamine 2; 3-dioxygenase Mechanism of action Nanomedicine Toxoplasmosis. |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4539 |
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| Kato, Kentaro; Ishiwa, Akiko; 加藤, 健太郎. |
| Enteric pathogens cause considerable public health concerns worldwide including tropical regions. Here, we review the roles of carbohydrates in the infection strategies of various enteric pathogens including viruses, bacteria and protozoa, which infect the epithelial lining of the human and animal intestine. At host cell entry, enteric viruses, including norovirus, recognize mainly histo-blood group antigens. At the initial step of bacterial infections, carbohydrates also function as receptors for attachment. Here, we describe the function of carbohydrates in infection by Salmonella enterica and several bacterial species that produce a variety of fimbrial adhesions. During invasion by enteropathogenic protozoa, apicomplexan parasites utilize sialic acids... |
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Palavras-chave: Bacteria; Carbohydrate; Enteric pathogen; Infection; Protozoa; Virus. |
| Ano: 2015 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4299 |
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