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Venancio-Brochi JC, Pereira LM, Calil FA, Teixeira O, Baroni L, Abreu-Filho PG, Braga GÚL, Nonato MC, Yatsuda AP. Glutathione reductase: A cytoplasmic antioxidant enzyme and a potential target for phenothiazinium dyes in Neospora caninum. Int J Biol Macromol 2021; 187:964-975. [PMID: 34310993 DOI: 10.1016/j.ijbiomac.2021.07.108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 05/21/2021] [Accepted: 07/15/2021] [Indexed: 11/21/2022]
Abstract
Neospora caninum causes heavy losses related to abortions in bovine cattle. This parasite developed a complex defense redox system, composed of enzymes as glutathione reductase (GR). Methylene blue (MB) impairs the activity of recombinant form of Plasmodium GR and inhibits the parasite proliferation in vivo and in vitro. Likewise, MB and its derivatives inhibits Neospora caninum proliferation, however, whether the MB mechanism of action is correlated to GR function remains unclear. Therefore, here, N. caninum GR (NcGR) was characterized and its potential inhibitors were determined. NcGR was found in the tachyzoite cytosol and has a similar structure and sequence compared to its homologs. We verified the in vitro activity of rNcGR (875 nM) following NADPH absorbance at 340 nM (100 mM KH2PO4, pH 7.5, 1 mM EDTA, ionic strength: 600 mM, 25 °C). rNcGR exhibited a Michaelian behavior (Km(GSSG):0.10 ± 0.02 mM; kcat(GSSG):0.076 ± 0.003 s-1; Km(NADPH):0.006 ± 0.001 mM; kcat(NADPH): 0.080 ± 0.003 s-1). The IC50 of MB,1,9-dimethyl methylene blue, new methylene blue, and toluidine blue O on rNcGR activity were 2.1 ± 0.2 μM, 11 ± 2 μM, 0.7 ± 0.1 μM, and 0.9 ± 0.2 μM, respectively. Our results suggest the importance of NcGR in N. caninum biology and antioxidant mechanisms. Moreover, data presented here strongly suggest that NcGR is an important target of phenothiazinium dyes in N. caninum proliferation inhibition.
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Affiliation(s)
- Jade Cabestre Venancio-Brochi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, Ribeirão Preto, Brazil
| | - Luiz Miguel Pereira
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, Ribeirão Preto, Brazil
| | - Felipe Antunes Calil
- Laboratório de Cristalografia de Proteínas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, Brazil; Ludwig Institute for Cancer Research, University of California, School of Medicine, 92093-0669 La Jolla, CA, USA
| | - Olívia Teixeira
- Laboratório de Cristalografia de Proteínas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, Brazil
| | - Luciana Baroni
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, Ribeirão Preto, Brazil
| | - Péricles Gama Abreu-Filho
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, Ribeirão Preto, Brazil
| | - Gilberto Úbida Leite Braga
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, Ribeirão Preto, Brazil
| | - Maria Cristina Nonato
- Laboratório de Cristalografia de Proteínas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, Brazil
| | - Ana Patrícia Yatsuda
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, Ribeirão Preto, Brazil.
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Harada M, Nagai J, Kurata R, Shimizu K, Cui X, Isagawa T, Semba H, Ishihara J, Yoshida Y, Takeda N, Maemura K, Yonezawa T. Establishment of Novel High-Standard Chemiluminescent Assay for NTPase in Two Protozoans and Its High-Throughput Screening. Mar Drugs 2020; 18:md18030161. [PMID: 32183121 PMCID: PMC7142789 DOI: 10.3390/md18030161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/14/2020] [Accepted: 03/10/2020] [Indexed: 01/18/2023] Open
Abstract
Toxoplasma gondii is a major protozoan parasite and infects human and many other warm-blooded animals. The infection leads to Toxoplasmosis, a serious issue in AIDS patients, organ transplant recipients and pregnant women. Neospora caninum, another type of protozoa, is closely related to Toxoplasma gondii. Infections of the protozoa in animals also causes serious diseases such as Encephalomyelitis and Myositis-Polyradiculitis in dogs or abortion in cows. Both Toxoplasma gondii and Neospora caninum have similar nucleoside triphosphate hydrolases (NTPase), NcNTPase and TgNTPase-I in Neospora caninum and Toxoplasma gondii, respectively. These possibly play important roles in propagation and survival. Thus, we targeted the enzymes for drug discovery and tried to establish a novel high-standard assay by a combination of original biochemical enzyme assay and fluorescent assay to determine ADP content. We then validated whether or not it can be applied to high-throughput screening (HTS). Then, it fulfilled criterion to carry out HTS in both of the enzymes. In order to identify small molecules having inhibitory effects on the protozoan enzyme, we also performed HTS using two synthetic compound libraries and an extract library derived from marine bacteria and then, identified 19 compounds and 6 extracts. Nagasaki University collected many extracts from over 18,000 marine bacteria found in local Omura bay, and continues to compile an extensive collection of synthetic compounds from numerous drug libraries established by Japanese chemists.
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Affiliation(s)
- Masamitsu Harada
- Center for Therapeutic Innovation, Gene Research Center for Frontiers Life Sciences, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-14 Sakamoto, Nagasaki 852-8523, Japan; (M.H.); (J.N.)
| | - Jun Nagai
- Center for Therapeutic Innovation, Gene Research Center for Frontiers Life Sciences, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-14 Sakamoto, Nagasaki 852-8523, Japan; (M.H.); (J.N.)
| | - Riho Kurata
- Education and Research Center for Pharmaceutical Sciences, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan;
| | - Kenji Shimizu
- Division of Immune Regulation, Institute for Genome Research, Tokushima University, Tokushima-shi, Tokushima 770-8505, Japan;
| | - Xiaofeng Cui
- School of Chemistry, Chemical Engineering and Life Sciences, School of Materials and Engineering, Wuhan University of Technology, 122 Loushi Rd, Wuhan 430070, Hubei, China;
| | - Takayuki Isagawa
- Department of Cardiovascular Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan; (T.I.); (K.M.)
| | - Hiroaki Semba
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Tokyo Japan Nishiazabu 3-2-19, Minato-ku, Tokyo 106-0031, Japan;
| | - Jun Ishihara
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan;
| | - Yasuhiro Yoshida
- Department of Immunology and Parasitology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan;
| | - Norihiko Takeda
- The University of Tokyo, Department of Cardiovascular Medicine, Graduate School of Medicine, 7-3-1, Hongo, Tokyo, Bunkyo-ku 113-8654, Japan;
| | - Koji Maemura
- Department of Cardiovascular Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan; (T.I.); (K.M.)
| | - Tomo Yonezawa
- Center for Therapeutic Innovation, Gene Research Center for Frontiers Life Sciences, Nagasaki University, Graduate School of Biomedical Sciences, 1-12-14 Sakamoto, Nagasaki 852-8523, Japan; (M.H.); (J.N.)
- Correspondence: or ; Tel./Fax: +81-95-819-8525
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Baroni L, Pereira LM, Maciver SK, Yatsuda AP. Functional characterisation of the actin-depolymerising factor from the apicomplexan Neospora caninum (NcADF). Mol Biochem Parasitol 2018; 224:26-36. [PMID: 30040977 DOI: 10.1016/j.molbiopara.2018.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/15/2018] [Accepted: 07/15/2018] [Indexed: 01/20/2023]
Abstract
Neospora caninum is an apicomplexan parasite that causes infectious abortion in cows. As an obligate intracellular parasite, N. caninum requires a host cell environment to survive and replicate. The locomotion and invasion mechanisms of apicomplexan parasites are centred on the actin-myosin system to propel the parasite forwards and into the host cell. The functions of actin, an intrinsically dynamic protein, are modulated by actin-binding proteins (ABPs). Actin-depolymerising factor (ADF) is a ubiquitous ABP responsible for accelerating actin turnover in eukaryotic cells and is one of the few known conserved ABPs from apicomplexan parasites. Apicomplexan ADFs have nonconventional properties compared with ADF/cofilins from higher eukaryotes. In the present paper, we characterised the ADF from N. caninum (NcADF) using computational and in vitro biochemical approaches to investigate its function in rabbit muscle actin dynamics. Our predicted computational tertiary structure of NcADF demonstrated a conserved structure and phylogeny with respect to other ADF/cofilins, although certain differences in filamentous actin (F-actin) binding sites were present. The activity of recombinant NcADF on heterologous actin was regulated in part by pH and the presence of inorganic phosphate. In addition, our data suggest a comparatively weak disassembly of F-actin by NcADF. Taken together, the data presented herein represent a contribution to the field towards the understanding of the role of ADF in N. caninum and a comparative analysis of ABPs in the phylum Apicomplexa.
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Affiliation(s)
- Luciana Baroni
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-930, Ribeirão Preto, SP, Brazil
| | - Luiz M Pereira
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-930, Ribeirão Preto, SP, Brazil
| | - Sutherland K Maciver
- Centre for Discovery Brain Sciences, Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, United Kingdom
| | - Ana P Yatsuda
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-930, Ribeirão Preto, SP, Brazil.
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4
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Matoba K, Shiba T, Takeuchi T, Sibley LD, Seiki M, Kikyo F, Horiuchi T, Asai T, Harada S. Crystallization and preliminary X-ray structural analysis of nucleoside triphosphate hydrolases from Neospora caninum and Toxoplasma gondii. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1445-8. [PMID: 21045291 PMCID: PMC3001644 DOI: 10.1107/s1744309110032136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Accepted: 08/10/2010] [Indexed: 11/10/2022]
Abstract
The nucleoside triphosphate hydrolases that are produced by Neospora caninum (NcNTPase) and Toxoplasma gondii (TgNTPase-I) have a different physiological function from the ubiquitous ecto-ATPases. The recombinant enzymes were crystallized at 293 K using polyethylene glycol 3350 as a precipitant and X-ray diffraction data sets were collected for NcNTPase (to 2.8 Å resolution) and TgNTPase-I (to 3.1 Å resolution) at 100 K using synchrotron radiation. The crystals of NcNTPase and TgNTPase-I belonged to the orthorhombic space group I222 (unit-cell parameters a = 93.6, b = 140.8, c = 301.1 Å) and the monoclinic space group P2(1) (unit-cell parameters a = 87.1, b = 123.5, c = 120.2 Å, β = 96.6°), respectively, with two NcNTPase (V(M) = 3.7 Å(3) Da(-1)) and four TgNTPase-I (V(M) = 2.7 Å(3) Da(-1)) molecules per asymmetric unit. SAD phasing trials using a data set (λ = 0.97904 Å) collected from a crystal of selenomethionylated NcNTPase gave an initial electron-density map of sufficient quality to build a molecular model of NcNTPase.
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Affiliation(s)
- Kazuaki Matoba
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Tomoo Shiba
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Tsutomu Takeuchi
- Department of Tropical Medicine and Parasitology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Makiko Seiki
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Fumi Kikyo
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Toshio Horiuchi
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Takashi Asai
- Department of Tropical Medicine and Parasitology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Shigeharu Harada
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
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Frössling J, Nødtvedt A, Lindberg A, Björkman C. Spatial analysis of Neospora caninum distribution in dairy cattle from Sweden. Geospat Health 2008; 3:39-45. [PMID: 19021107 DOI: 10.4081/gh.2008.230] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The national herd prevalence and spatial distribution of Neospora caninum infected dairy herds in Sweden were investigated. The study was based on a bulk milk survey comprising samples from 2,978 herds. Test-positive herds were found in all parts of Sweden and the overall prevalence of test-positive herds was 8.3% (95% confidence interval = 7.3-9.3%). The presence of spatial autocorrelation was tested using the Moran's I test. Possible clusters of test-positive herds were identified by applying the local indicator of spatial association (LISA) test statistic and the spatial scan statistic. Analysis based on data aggregated by postal code areas as well as analysis based on exact coordinates identified significant clusters of high prevalence in the middle parts of Sweden and low prevalence in the south. This was not expected considering the results from other European studies of N. caninum in cattle. However, the findings are supported by the distribution of previously known case herds.
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Affiliation(s)
- Jenny Frössling
- Department of Disease Control and Epidemiology, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
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6
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Müller J, Naguleswaran A, Müller N, Hemphill A. Neospora caninum: functional inhibition of protein disulfide isomerase by the broad-spectrum anti-parasitic drug nitazoxanide and other thiazolides. Exp Parasitol 2007; 118:80-8. [PMID: 17720161 DOI: 10.1016/j.exppara.2007.06.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 06/18/2007] [Accepted: 06/25/2007] [Indexed: 11/23/2022]
Abstract
Nitazoxanide (NTZ) and several NTZ-derivatives (thiazolides) have been shown to exhibit considerable anti-Neospora caninum tachyzoite activity in vitro. We coupled tizoxanide (TIZ), the deacetylated metabolite, to epoxy-agarose-resin and performed affinity chromatography with N. caninum tachyzoite extracts. Two main protein bands of 52 and 43kDa were isolated. The 52kDa protein was readily recognized by antibodies directed against NcPDI, and mass spectrometry confirmed its identity. Poly-histidine-tagged NcPDI-cDNA was expressed in Escherichia coli and recombinant NcPDI (recNcPDI) was purified by Co2+-affinity chromatography. By applying an enzyme assay based on the measurement of insulin crosslinking activity, recNcPDI exhibited properties reminiscent for PDIs, and its activity was impaired upon the addition of classical PDI inhibitors such as bacitracin (1-2mM), para-chloromercuribenzoic acid (0.1-1mM) and tocinoic acid (0.1-1mM). RecNcPDI-mediated insulin crosslinking was inhibited by NTZ (5-100 microM) in a dose-dependent manner. In addition, the enzymatic activity of recNcPDI was inhibited by those thiazolides that also affected parasite proliferation. Thus, thiazolides readily interfere with NcPDI, and possibly also with PDIs from other microorganisms susceptible to thiazolides.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland.
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Vonlaufen N, Naguleswaran A, Gianinazzi C, Hemphill A. Characterization of the fetuin-binding fraction of Neospora caninum tachyzoites and its potential involvement in host-parasite interactions. Parasitology 2007; 134:805-17. [PMID: 17291396 DOI: 10.1017/s0031182006002186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Terminal sialic acid residues on surface-associated glycoconjugates mediate host cell interactions of many pathogens. Addition of sialic acid-rich fetuin enhanced, and the presence of the sialidiase inhibitor 2-deoxy-2,3-dehydro-N-acetylneuraminic acid reduced, the physical interaction of Neospora caninum tachyzoites and bradyzoites with Vero cell monolayers. Thus, Neospora extracts were subjected to fetuin-agarose affinity chromatography in order to isolate components potentially interacting with sialic acid residues. SDS-PAGE and silver staining of the fetuin binding fraction revealed the presence of a single protein band of approximately 65 kDa, subsequently named NcFBP (Neospora caninum fetuin-binding protein), which was localized at the apical tip of the tachyzoites and was continuously released into the surrounding medium in a temperature-independent manner. NcFBP readily interacted with Vero cells and bound to chondroitin sulfate A and C, and anti-NcFBP antibodies interfered in tachyzoite adhesion to host cell monolayers. In additon, analysis of the fetuin binding fraction by gelatin substrate zymography was performed, and demonstrated the presence of two bands of 96 and 140 kDa exhibiting metalloprotease-activity. The metalloprotease activity readily degraded glycosylated proteins such as fetuin and bovine immunoglobulin G heavy chain, whereas non-glycosylated proteins such as bovine serum albumin and immunoglobulin G light chain were not affected. These findings suggest that the fetuin-binding fraction of Neospora caninum tachyzoites contains components that could be potentially involved in host-parasite interactions.
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Affiliation(s)
- N Vonlaufen
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland
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Liao M, Ma L, Bannai H, Lee EG, Xie Z, Tang X, Zhang H, Xuan X, Fujisaki K. Identification of a protein disulfide isomerase of Neospora caninum in excretory-secretory products and its IgA binding and enzymatic activities. Vet Parasitol 2006; 139:47-56. [PMID: 16574326 DOI: 10.1016/j.vetpar.2006.02.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/16/2006] [Accepted: 02/21/2006] [Indexed: 11/24/2022]
Abstract
A protein disulfide isomerase of Neospora caninum (NcPDI) with a molecular weight of 50kDa was identified in tachyzoite lysate and excretory-secretory (ES) products. The IgA antibody in 58.0% of the individual cattle tear samples recognized the NcPDI, which suggests that the PDI-specific antibody may be involved in defense against parasites. In addition, PDI-specific inhibitors and NcPDI antiserum showed inhibitory effects on the growth of N. caninum tachyzoites. Furthermore, the purified recombinant NcPDI demonstrated biological activities in vitro by catalysis and refolding of reduced RNase A and assisted in the recovery of native lysozyme. These findings indicate that NcPDI possesses PDI-specific enzymatic activity and could be a putative target for chemotherapy for neosporosis.
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Affiliation(s)
- Min Liao
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
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9
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Naguleswaran A, Alaeddine F, Guionaud C, Vonlaufen N, Sonda S, Jenoe P, Mevissen M, Hemphill A. Neospora caninum protein disulfide isomerase is involved in tachyzoite-host cell interaction. Int J Parasitol 2005; 35:1459-72. [PMID: 16129440 DOI: 10.1016/j.ijpara.2005.06.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 06/06/2005] [Accepted: 06/09/2005] [Indexed: 11/23/2022]
Abstract
We have previously shown that treatment of Neospora caninum tachyzoites with the aspartyl protease inhibitor pepstatin A reduces host cell invasion [Naguleswaran, A., Muller, N., Hemphill, A., 2003. Neospora caninum and Toxoplasma gondii: a novel adhesion/invasion assay reveals distinct differences in tachyzoite-host cell interactions. Exp. Parasitol. 104, 149-158]. Pepstatin A-affinity-chromatography led to the isolation of a major band of approximately 52 kDa which was identified as a homologue of a previously described Toxoplasma gondii putative protein disulfide isomerase (TgPDI) through tandem mass spectrometry. A BLAST search against N. caninum expressed sequence tags (ESTs) on the ApiDots server using TgPDI cDNA as query sequence revealed a 2251 bp PDI-like consensus (NcPDI), which shows 94% identity to the T. gondii homologue. In N. caninum tachyzoites, NcPDI was found mainly in the soluble hydrophilic fraction. Immunofluorescence showed that expression of NcPDI was dramatically down-regulated in the bradyzoite stage, and immunogold-EM on tachyzoites localised the protein to the cytoplasm, mostly in close vicinity to the nuclear membrane, to the micronemes, and to the parasite cell surface. However, NcPDI was absent in rhoptries and dense granules. Preincubation of tachyzoites with the sulfhydryl blocker 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), p-chloromercuribenzoic acid (pCMBA), and with the PDI inhibitor bacitracin reduced adhesion of parasites to host cells. In addition, incubation of N. caninum tachyzoites with affinity-purified anti-NcPDI antibodies reduced host cell adhesion. PDIs catalyse the formation, reduction or isomerisation of disulfide bonds. Many major components of the adhesion and invasion machinery of apicomplexan parasites are cysteine-rich and dependent on correct folding via disulfide bond formation. Thus, our data points towards an important role for surface-associated NcPDI in Neospora-host cell interaction.
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Affiliation(s)
- Arunasalam Naguleswaran
- Institute of Parasitology, University of Berne, Länggass-Strasse 122, CH-3012 Berne, Switzerland
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Wilson AP, Thelen JJ, Lakritz J, Brown CR, Marsh AE. The identification of a sequence related to apicomplexan enolase from Sarcocystis neurona. Parasitol Res 2004; 94:354-60. [PMID: 15549383 DOI: 10.1007/s00436-004-1224-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 08/19/2004] [Indexed: 11/24/2022]
Abstract
Equine protozoal myeloencephalitis (EPM) is a neurological disease caused by Sarcocystis neurona, an apicomplexan parasite. S. neurona is also associated with EPM-like diseases in marine and small mammals. The mechanisms of transmission and ability to infect a wide host range remain obscure; therefore, characterization of essential proteins may provide evolutionary information allowing the development of novel chemotherapeutics that target non-mammalian biochemical pathways. In the current study, two-dimensional electrophoresis and matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry were combined to characterize and identify an enolase protein from S. neurona based on peptide homology to the Toxoplasma gondii protein. Enolase is thought to be a vestigial, non-photosynthetic protein resulting from an evolutionary endosymbiosis event of an apicomplexan ancestor with green algae. Enolase has also been suggested to play a role in parasite stage conversion for T. gondii. Characterization of this protein in S. neurona and comparison to other protozoans indicate a biochemical similarity of S. neurona enolase to other tissue-cyst forming coccidians that cause encephalitis.
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Affiliation(s)
- A P Wilson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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Cho MH, Na BK, Song KJ, Cho JH, Kang SW, Lee KH, Song CY, Kim TS. Cloning, expression, and characterization of iron-containing superoxide dismutase from Neospora caninum. J Parasitol 2004; 90:278-85. [PMID: 15165050 DOI: 10.1645/ge-3222] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A gene encoding superoxide dismutase (SOD) from Neospora caninum, a causative agent of neosporosis, has been cloned and its gene product functionally expressed and characterized. The gene had an open reading frame of 606 bp and deduced 201 amino acids. Sequence analysis showed that the gene had conserved metal-binding residues and conserved amino acid residues that were found in Fe-SODs. Comparison of the deduced amino acid sequence of the enzyme with previously reported Fe-SOD amino acid sequences of the other parasitic protozoans revealed significant high homology. The coding region of the N. caninum Fe-SOD was cloned and functionally expressed in Escherichia coli. Enzyme activity of the expressed protein was inhibited by hydrogen peroxide but not by sodium azide and potassium cyanide, and the enzyme showed similar biochemical properties with typical Fe-SODs of other parasitic protozoans. Southern blot analysis showed that the SOD gene appears to be present as a single-copy gene in N. caninum genome. Semiquantitative reverse transcription-polymerase chain reaction and immunoblot using antiserum raised against the purified recombinant protein showed that Fe-SOD is expressed in both developmental stages of N. caninum, i.e., in bradyzoites and tachyzoites. In an immunofluorescence assay, the enzyme was localized on the cell surface of N. caninum tachyzoites. These results suggest that Fe-SOD might be essential for the intracellular survival of N. caninum and may play an important role in the pathogenesis of the parasite by protecting the parasite from oxidative killing.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Northern
- Blotting, Southern
- Cloning, Molecular
- DNA, Complementary/biosynthesis
- DNA, Complementary/chemistry
- Electrophoresis, Polyacrylamide Gel
- Fluorescent Antibody Technique, Indirect
- Gene Expression Regulation, Enzymologic
- Hydrogen-Ion Concentration
- Molecular Sequence Data
- Neospora/enzymology
- Neospora/genetics
- Polymerase Chain Reaction
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- Sequence Alignment
- Sequence Homology, Amino Acid
- Superoxide Dismutase/chemistry
- Superoxide Dismutase/genetics
- Superoxide Dismutase/metabolism
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Affiliation(s)
- Min-Hee Cho
- Department of Biology, College of Natural Science, Chung-Ang University, Seoul 156-756, Korea
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12
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Abstract
NcSUB1 (formerly known as NC-p65) is the first molecularly described proteolytic enzyme of the intracellular protozoan parasite Neospora caninum. This report describes the characterization of a rabbit anti-N54, which is an antiserum generated against an internal fragment of NcSUB1 (amino acids 649-783). In immunofluorescence studies rabbit and-N54 labeled the apical end of the fixed parasite. By immuno-gold electron microscopy, the antibody bound primarily to the microneme organelles of the parasite. Analysis of secreted parasitic proteins indicated that a protein of molecular weight 65 kDa (reduced) or 55 kDa (nonreduced) was recognized bythe antibody. The same secreted proteins were affinity purified with rabbit anti-N54-coupled resins and were shown to contain major proteolytic activity by zymography. Thus, rabbit anti-N54 is the first antibody developed for N. caninum that binds to themicroneme proteins and recognizes a major secreted enzyme.
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Affiliation(s)
- Kitland Louie
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, California 95616, USA
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13
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Abstract
The NC-p65 cDNA is the first protease sequence cloned and described for Neospora caninum. The full length cDNA was isolated by 5'- and 3'-rapid amplification of cDNA ends (RACE). NC-p65 was composed of 865 amino acids with a predicted signal sequence, a proposed pro-domain, and an internal region of conserved repeats. Analysis of the deduced amino acid sequence revealed that this protein had homology to the serine proteases of the subtilisin-like superfamily (subtilases) and had a predicted active site made up of the catalytic residues, Asp 253, His 309. and Ser 484. Antibodies to recombinant NC-p65 recognized multiple bands on Neospora lysate immunoblots, but most intensely stained a 65 kDa band. When N. caninum proteins were purified with affinity resins specific for NC-p65 and analyzed for enzyme activity, a single specific band of reaction was observed on gelatin-saturated zymograms.
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Affiliation(s)
- K Louie
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis 95616, USA
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14
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Abstract
The plastid DNA of Neospora caninum encodes a homologue of the rpoB gene, which is believed to encode a subunit of a bacterial or chloroplast-like RNA polymerase. The predicted protein product of the N. caninum rpoB gene has three in-frame UGA codons which appear to encode tryptophan residues rather than act as stop codons. Based on the nucleotide sequence of a portion of the ssrRNA gene of the N. caninum plastid, a model for suppression of UGA termination in this plastid is presented.
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Affiliation(s)
- N Lang-Unnasch
- Department of Medicine, University of Alabama at Birmingham, 35294-2170, USA.
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15
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Asai T, Howe DK, Nakajima K, Nozaki T, Takeuchi T, Sibley LD. Neospora caninum: tachyzoites express a potent type-I nucleoside triphosphate hydrolase. Exp Parasitol 1998; 90:277-85. [PMID: 9806873 DOI: 10.1006/expr.1998.4346] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have identified type I nucleoside triphosphate hydrolase (NTPase; EC 3.6. 1.3) activity, previously thought to be restricted to the virulent strains of Toxoplasma gondii, in the cell extracts of Neospora caninum tachyzoites. Sequence analysis of a complete cDNA from Nc-1 strain indicated that N. caninum NTPases shared approximately 69% identity to the NTPases of T. gondii and are most similar to the NTPase-I isozyme. Southern blot analysis of genomic DNA and sequence analysis of two independent NTP clones from the Nc-1 strain revealed the presence of multiple genes, at least two of which are transcribed. Substrate specificity and Km values for MgATP2- and MgADP- hydrolysis for recombinant or partially purified native NcNTPase were the same as those for the type I isozyme (NTPase-I). Significantly, no type II enzyme (NTPase-II) activity for NDP hydrolysis was detected in cell extracts of N. caninum, although it is universally present in all T. gondii strains that have been tested. This intriguing difference between these two closely related apicomplexan parasites may provide insight into the function of the NTPases during intracellular parasitism.
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Affiliation(s)
- T Asai
- Department of Tropical Medicine and Parasitology, Keio University School of Medicine, Shinjuku, Tokyo, 160, Japan
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