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Hiltunen Thorén M, Onuț-Brännström I, Alfjorden A, Pecková H, Swords F, Hooper C, Holzer AS, Bass D, Burki F. Comparative genomics of Ascetosporea gives new insight into the evolutionary basis for animal parasitism in Rhizaria. BMC Biol 2024; 22:103. [PMID: 38702750 PMCID: PMC11069148 DOI: 10.1186/s12915-024-01898-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Ascetosporea (Endomyxa, Rhizaria) is a group of unicellular parasites infecting aquatic invertebrates. They are increasingly being recognized as widespread and important in marine environments, causing large annual losses in invertebrate aquaculture. Despite their importance, little molecular data of Ascetosporea exist, with only two genome assemblies published to date. Accordingly, the evolutionary origin of these parasites is unclear, including their phylogenetic position and the genomic adaptations that accompanied the transition from a free-living lifestyle to parasitism. Here, we sequenced and assembled three new ascetosporean genomes, as well as the genome of a closely related amphizoic species, to investigate the phylogeny, origin, and genomic adaptations to parasitism in Ascetosporea. RESULTS Using a phylogenomic approach, we confirm the monophyly of Ascetosporea and show that Paramyxida group with Mikrocytida, with Haplosporida being sister to both groups. We report that the genomes of these parasites are relatively small (12-36 Mb) and gene-sparse (~ 2300-5200 genes), while containing surprisingly high amounts of non-coding sequence (~ 70-90% of the genomes). Performing gene-tree aware ancestral reconstruction of gene families, we demonstrate extensive gene losses at the origin of parasitism in Ascetosporea, primarily of metabolic functions, and little gene gain except on terminal branches. Finally, we highlight some functional gene classes that have undergone expansions during evolution of the group. CONCLUSIONS We present important new genomic information from a lineage of enigmatic but important parasites of invertebrates and illuminate some of the genomic innovations accompanying the evolutionary transition to parasitism in this lineage. Our results and data provide a genetic basis for the development of control measures against these parasites.
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Affiliation(s)
- Markus Hiltunen Thorén
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden.
- Present Address: Department of Ecology, Environment and Plant Sciences, Stockholm University, Svante Arrhenius V. 20 A, Stockholm, SE-114 18, Sweden.
- Present Address: The Royal Swedish Academy of Sciences, Stockholm, SE-114 18, Sweden.
| | - Ioana Onuț-Brännström
- Present Address: Department of Ecology and Genetics, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden
- Present Address: Natural History Museum, Oslo University, Oslo, 0562, Norway
| | - Anders Alfjorden
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden
| | - Hana Pecková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Fiona Swords
- Marine Institute, Rinville, Oranmore, H91R673, Ireland
| | - Chantelle Hooper
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset, DT4 8UB, UK
- Sustainable Aquaculture Futures, Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Astrid S Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 370 05, Czech Republic
- Division of Fish Health, University of Veterinary Medicine, Veterinärplatz 1, Vienna, 1210, Austria
| | - David Bass
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset, DT4 8UB, UK
- Sustainable Aquaculture Futures, Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Natural History Museum (NHM), Science, London, SW7 5BD, UK
| | - Fabien Burki
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden.
- Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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Burrell A, Marugan-Hernandez V, Graefin Von Der Recke K, Aguiar-Martins K, Gabriel HB, Tomley FM, Vaughan S. Refractile bodies of Eimeria tenella are proteinaceous membrane-less organelles that undergo dynamic changes during infection. Front Cell Infect Microbiol 2023; 13:1082622. [PMID: 37033474 PMCID: PMC10081493 DOI: 10.3389/fcimb.2023.1082622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 02/27/2023] [Indexed: 03/11/2023] Open
Abstract
IntroductionRefractile bodies (RB) are large membrane-less organelles (MLO) of unknown function found as a prominent mismatched pair within the sporozoite stages of all species of Eimeria, parasitic coccidian protozoa.MethodsHigh resolution imaging methods including time-lapse live confocal microscopy and serial block face-scanning electron microscopy (SBF-SEM) were used to investigate the morphology of RB and other intracellular organelles before and after sporozoite invasion of host cells.ResultsLive cell imaging of MDBK cells infected with E. tenella sporozoites confirmed previous reports that RB reduce from two to one post-infection and showed that reduction in RB number occurs via merger of the anterior RB with the posterior RB, a process that lasts 20-40 seconds and takes place between 2- and 5-hours post-infection. Ultrastructural studies using SBF-SEM on whole individual sporozoites, both pre- and post-host cell invasion, confirmed the live cell imaging observations and showed also that changes to the overall sporozoite cell shape accompanied RB merger. Furthermore, the single RB post-merger was found to be larger in volume than the two RB pre-merger. Actin inhibitors were used to investigate a potential role for actin in RB merger, Cytochalasin D significantly inhibited both RB merger and the accompanying changes in sporozoite cell shape.DiscussionMLOs in eukaryotic organisms are characterised by their lack of a membrane and ability to undergo liquid-liquid phase separation (LLPS) and fusion, usually in an actin-mediated fashion. Based on the changes in sporozoite cell shape observed at the time of RB merger together with a potential role for actin in this process, we propose that RB are classed as an MLO and recognised as one of the largest MLOs so far characterised.
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Affiliation(s)
- Alana Burrell
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, University of London, North Mymms, United Kingdom
| | - Virginia Marugan-Hernandez
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, University of London, North Mymms, United Kingdom
- *Correspondence: Virginia Marugan-Hernandez, ; Sue Vaughan,
| | - Karolin Graefin Von Der Recke
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, University of London, North Mymms, United Kingdom
| | - Kelsilandia Aguiar-Martins
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, University of London, North Mymms, United Kingdom
| | - Heloisa Berti Gabriel
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Fiona M. Tomley
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, University of London, North Mymms, United Kingdom
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
- *Correspondence: Virginia Marugan-Hernandez, ; Sue Vaughan,
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Olajide JS, Xiong L, Yang S, Qu Z, Xu X, Yang B, Wang J, Liu B, Ma X, Cai J. Eimeria falciformis secretes extracellular vesicles to modulate proinflammatory response during interaction with mouse intestinal epithelial cells. Parasit Vectors 2022; 15:245. [PMID: 35804396 PMCID: PMC9270845 DOI: 10.1186/s13071-022-05364-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/15/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Protozoan parasite secretions can be triggered by various modified media and diverse physicochemical stressors. Equally, host-parasite interactions are known to co-opt the exchange and secretion of soluble biochemical components. Analysis of Eimeria falciformis sporozoite secretions in response to interaction with mouse intestinal epithelial cells (MIECs) may reveal parasite secretory motifs, protein composition and inflammatory activities of E. falciformis extracellular vesicles (EVs). METHODS Eimeria falciformis sporozoites were allowed to interact with inactivated MIECs. Parasite secretions were separated into EV and vesicle-free (VF) fractions by discontinuous centrifugation and ultracentrifugation. Secreted EVs were purified in an iodixanol density gradient medium and the protein composition of both EV and VF fractions were analyzed by liquid chromatoraphy-tandem mass spectroscopy. The inflammatory activities of E. falciformis sporozoite EV on MIECs were then investigated. RESULTS During the interaction of E. falciformis sporozoites with inactivated MIECs, the parasite secreted VF and vesicle-bound molecules. Eimeria falciformis vesicles are typical pathogenic protozoan EVs with a mean diameter of 264 ± 2 nm, and enclosed heat shock protein (Hsp) 70 as classical EV marker. Refractile body-associated aspartyl proteinase (or eimepsin), GAP45 and aminopeptidase were the main components of E. falciformis sporozoite EVs, while VF proteins include Hsp90, actin, Vps54 and kinases, among others. Proteomic data revealed that E. falciformis EV and VF proteins are aggregates of bioactive, antigenic and immunogenic molecules which act in concert for E. falciformis sporozoite motility, pathogenesis and survival. Moreover, in MIECs, E. falciformis EVs induced upregulation of gene expression and secretion of IL-1β, IL-6, IL-17, IL-18, MCP1 as well as pyroptosis-dependent caspase 11 and NLRP6 inflammasomes with the concomitant secretion of lactate dehydrogenase. CONCLUSIONS Eimeria falciformis sporozoite interaction with MIECs triggered the secretion of immunogenic and antigenic proteins. In addition, E. falciformis sporozoite EVs constitute parasite-associated molecular pattern that induced inflammatory response and cell death. This study offers additional insight in the secretion and protein composition of E. falciformis secretomes as well as the proinflammatory functions of E. falciformis sporozoite EVs.
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Affiliation(s)
- Joshua Seun Olajide
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
- Centre for Distance Learning, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Ling Xiong
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Shunli Yang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Zigang Qu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Xiao Xu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Bin Yang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Jing Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Baohong Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Xueting Ma
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
| | - Jianping Cai
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 China
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Abstract
Apicomplexans are important pathogens that cause severe infections in humans and animals. The biology and pathogeneses of these parasites have shown that proteins are intrinsically modulated during developmental transitions, physiological processes and disease progression. Also, proteins are integral components of parasite structural elements and organelles. Among apicomplexan parasites, Eimeria species are an important disease aetiology for economically important animals wherein identification and characterisation of proteins have been long-winded. Nonetheless, this review seeks to give a comprehensive overview of constitutively expressed Eimeria proteins. These molecules are discussed across developmental stages, organelles and sub-cellular components vis-à-vis their biological functions. In addition, hindsight and suggestions are offered with intention to summarise the existing trend of eimerian protein characterisation and to provide a baseline for future studies.
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Marugan-Hernandez V, Sanchez-Arsuaga G, Vaughan S, Burrell A, Tomley FM. Do All Coccidia Follow the Same Trafficking Rules? Life (Basel) 2021; 11:life11090909. [PMID: 34575057 PMCID: PMC8465013 DOI: 10.3390/life11090909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 01/06/2023] Open
Abstract
The Coccidia are a subclass of the Apicomplexa and include several genera of protozoan parasites that cause important diseases in humans and animals, with Toxoplasma gondii becoming the ‘model organism’ for research into the coccidian molecular and cellular processes. The amenability to the cultivation of T. gondii tachyzoites and the wide availability of molecular tools for this parasite have revealed many mechanisms related to their cellular trafficking and roles of parasite secretory organelles, which are critical in parasite-host interaction. Nevertheless, the extrapolation of the T. gondii mechanisms described in tachyzoites to other coccidian parasites should be done carefully. In this review, we considered published data from Eimeria parasites, a coccidian genus comprising thousands of species whose infections have important consequences in livestock and poultry. These studies suggest that the Coccidia possess both shared and diversified mechanisms of protein trafficking and secretion potentially linked to their lifecycles. Whereas trafficking and secretion appear to be well conversed prior to and during host-cell invasion, important differences emerge once endogenous development commences. Therefore, further studies to validate the mechanisms described in T. gondii tachyzoites should be performed across a broader range of coccidians (including T. gondii sporozoites). In addition, further genus-specific research regarding important disease-causing Coccidia is needed to unveil the individual molecular mechanisms of pathogenesis related to their specific lifecycles and hosts.
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Affiliation(s)
- Virginia Marugan-Hernandez
- The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms AL9 7TA, UK; (G.S.-A.); (F.M.T.)
- Correspondence: ; Tel.: +44-(0)-17-0766-9445
| | - Gonzalo Sanchez-Arsuaga
- The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms AL9 7TA, UK; (G.S.-A.); (F.M.T.)
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK;
| | - Alana Burrell
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK;
| | - Fiona M. Tomley
- The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms AL9 7TA, UK; (G.S.-A.); (F.M.T.)
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Gu X, Liu H, Li C, Fang S, Cui P, Liao Q, Zhang S, Wang S, Duan C, Yu F, Suo X, Liu X. Selection and characterization of a precocious line of Eimeria media. Parasitol Res 2019; 118:3033-3041. [PMID: 31407118 DOI: 10.1007/s00436-019-06422-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/02/2019] [Indexed: 11/25/2022]
Abstract
Coccidiosis, caused by the infection of Eimeria parasites, is one of the most common diseases in domestic rabbits. Live anticoccidial vaccine formulated with attenuated precocious lines of pathogenic eimerian parasites is expected to be valuable for the control of rabbit coccidiosis as a similar strategy to produce anticoccidial vaccines against chicken coccidiosis has being used for several decades. Eimeria media, moderate pathogenic, is widespread in China. Therefore, attenuated anticoccidial vaccines against rabbit coccidiosis should contain vaccine strain(s) of E. media. In this study, a precocious line of E. media (Empre) was selected by collecting and propagating the early excreted oocysts with 16 successive generations. The prepatent period of Empre reduced from 108 h of its parental strain (Emwt) to 70 h. The fecundity of Empre was about 1/10 to 1/3 lower than that of Emwt. Each sporocyst of Empre sporulated oocyst contained only one large refractile body instead of two smaller ones seen in the parental strain. When vaccinated with 1 × 103 or 1 × 104 precocious line oocysts, the rabbits were completely protected against homologous challenge with the parental strain 14 days post challenge by terms of body weight gain and oocyst output counting, indicating the efficacy of Empre. Meanwhile, all immunized rabbits showed no clinical sign post immunization, indicating the safety of Empre. For co-immunization, 1 × 103Empre oocysts and 5 × 102 oocysts of a precocious line of E. intestinalis (EIP8) were inoculated to each rabbit in a trial. No diarrhea or mortality was found after vaccination, and the weight gains of the vaccinated group were similar to that of unvaccinated-unchallenged control (UUC) group, while the weight gains of the vaccinated group were similar to that of unvaccinated-unchallenged control (UUC) group (P > 0.05), but significantly higher than that of UCC group (P < 0.01) after challenge, indicating it is safe and effective when using co-immunization. These results together show that Empre, as a precocious line, is a good candidate of precocious line of E. media for anticoccidial vaccine development.
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Affiliation(s)
- Xiaolong Gu
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
- College of Animal Science and Technology, Hebei North University, Zhangjiakou, 075000, China
| | - Hongbin Liu
- Department of Pharmacology, Hebei North University, Zhangjiakou, 075000, China
| | - Chao Li
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Sufang Fang
- College of Animal Science and Technology, Hebei North University, Zhangjiakou, 075000, China
| | - Ping Cui
- College of Animal Science and Technology, Hebei North University, Zhangjiakou, 075000, China
| | - Qin Liao
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Sixin Zhang
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Si Wang
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Chunhui Duan
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Fang Yu
- Laboratory of Anatomy of Domestic Animals, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xun Suo
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xianyong Liu
- National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
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Thabet A, Honscha W, Daugschies A, Bangoura B. Quantitative proteomic studies in resistance mechanisms of Eimeria tenella against polyether ionophores. Parasitol Res 2017; 116:1553-1559. [PMID: 28352944 DOI: 10.1007/s00436-017-5432-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/21/2017] [Indexed: 11/25/2022]
Abstract
Polyether ionophores are widely used to treat and control coccidiosis in chickens. Widespread use of anticoccidials resulted in worldwide resistance. Mechanisms of resistance development and expansion are complex and poorly understood. Relative proteomic quantification using LC-MS/MS was used to compare sensitive reference strains (Ref-1, Ref-2) with putatively resistant and moderately sensitive field strains (FS-R, FS-mS) of Eimeria tenella after isotopic labelling with tandem mass tags (TMT). Ninety-seven proteins were identified, and 25 of them were regulated. Actin was significantly upregulated in resistant strains in comparison with their sensitive counterparts. On the other hand, microneme protein (MIC4) was downregulated in resistant strains. Optimization of labelling E. tenella sporozoites by TMT might identify further proteins that play a role in the obvious complex mechanism leading to resistance against Monensin.
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Affiliation(s)
- Ahmed Thabet
- Institute of Parasitology, Faculty of Veterinary Medicine, Centre for Infectious Diseases, University of Leipzig, An den Tierkliniken 35, 04103, Leipzig, Germany
| | - Walther Honscha
- Institute of Pharmacy, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Leipzig, Germany
| | - Arwid Daugschies
- Institute of Parasitology, Faculty of Veterinary Medicine, Centre for Infectious Diseases, University of Leipzig, An den Tierkliniken 35, 04103, Leipzig, Germany
- Albrecht-Daniel-Thaer-Institute, Leipzig, Germany
| | - Berit Bangoura
- Institute of Parasitology, Faculty of Veterinary Medicine, Centre for Infectious Diseases, University of Leipzig, An den Tierkliniken 35, 04103, Leipzig, Germany.
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Sojka D, Hartmann D, Bartošová-Sojková P, Dvořák J. Parasite Cathepsin D-Like Peptidases and Their Relevance as Therapeutic Targets. Trends Parasitol 2016; 32:708-723. [PMID: 27344362 DOI: 10.1016/j.pt.2016.05.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/27/2016] [Accepted: 05/25/2016] [Indexed: 11/18/2022]
Abstract
Inhibition of aspartic cathepsin D-like peptidases (APDs) has been often discussed as an antiparasite intervention strategy. APDs have been considered as virulence factors of Trypanosoma cruzi and Leishmania spp., and have been demonstrated to have important roles in protein trafficking mechanisms of apicomplexan parasites. APDs also initiate blood digestion as components of multienzyme proteolytic complexes in malaria, platyhelminths, nematodes, and ticks. Increasing DNA and RNA sequencing data indicate that parasites express multiple APD isoenzymes of various functions that can now be specifically evaluated using new functional-genomic and biochemical tools, from which we can further assess the potential of APDs as targets for novel effective intervention strategies against parasitic diseases that still pose an alarming threat to mankind.
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Affiliation(s)
- Daniel Sojka
- Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice 370 05, Czech Republic.
| | - David Hartmann
- Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice 370 05, Czech Republic
| | - Pavla Bartošová-Sojková
- Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice 370 05, Czech Republic
| | - Jan Dvořák
- Institute of Molecular Genetics, The Czech Academy of Sciences, Prague 14220, Czech Republic; Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague 16610, Czech Republic; School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK
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Identification and characterization of a cathepsin-L-like peptidase in Eimeria tenella. Parasitol Res 2014; 113:4335-48. [DOI: 10.1007/s00436-014-4107-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 08/26/2014] [Indexed: 11/26/2022]
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Dong H, Wang Y, Han H, Li T, Zhao Q, Zhu S, Li L, Wu Y, Huang B. Identification and characterization of an Eimeria-conserved protein in Eimeria tenella. Parasitol Res 2013; 113:735-45. [PMID: 24271155 DOI: 10.1007/s00436-013-3703-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 11/12/2013] [Indexed: 11/29/2022]
Abstract
The precocious lines of Eimeria spp. have unique phenotypes. However, the genetic basis of the precocious phenotype is still poorly understood. The identification of Eimeria genes controlling the precocious phenotype is of immense importance in the fight against coccidiosis. In the present study, a novel gene of Eimeria maxima was cloned using rapid amplification of cDNA ends (RACE) based on the expressed sequence tag (EST). Homologous genes were also found in Eimeria tenella and Eimeria acervulina. Alignment of the amino acid sequences from E. tenella, E. maxima, and E. acervulina showed 80-86 % identity, demonstrating a conserved protein in different Eimeria spp. This gene, designated Eimeria-conserved protein (ECP), contained 235 amino acids with a predicted molecular mass of 25.4 kDa and had 100 % identity with one annotated protein from E. maxima (Emax_0517). Real-time PCR and Western blot analysis revealed that the expression of ECP at mRNA and protein level in E. tenella is developmentally regulated. Messenger RNA levels from the ECP gene were higher in sporozoites than in other developmental stages (unsporulated oocysts, sporulated oocysts, and second-generation merozoites). Expression of ECP protein was detected in unsporulated oocysts, increased in abundance in sporulated oocysts, and was most prominent in sporozoites. Thereafter, the level of the ECP protein decreased, and no ECP-specific protein was detected in second-generation merozoites. Immunostaining with anti-rECP indicated that ECP is highly concentrated in both refractile bodies (RB) of free sporozoites, but is located at the apical end of the sporozoites after invasion of DF-1 cells. The specific staining of the ECP protein becomes more intense in trophozoites and immature first-generation schizonts, but decreases in mature first-generation schizonts. Inhibition of the function of ECP using specific antibodies reduced the ability of E. tenella sporozoites to invade host cells. Compared with the parent strain, both mRNA and protein expression levels in the sporulated oocyst were downregulated in the precocious line of E. tenella. These results suggest that ECP may be involved in invasion and development of the first-generation merogony stage of E. tenella. Findings of downregulation of ECP mRNA and protein expression in the precocious line enrich the study of the precocious phenotype of Eimeria.
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Affiliation(s)
- Hui Dong
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, No. 518 Ziyue Road, Minhang District, Shanghai, 200241, China
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Katrib M, Ikin RJ, Brossier F, Robinson M, Slapetova I, Sharman PA, Walker RA, Belli SI, Tomley FM, Smith NC. Stage-specific expression of protease genes in the apicomplexan parasite, Eimeria tenella. BMC Genomics 2012; 13:685. [PMID: 23216867 PMCID: PMC3770453 DOI: 10.1186/1471-2164-13-685] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 12/04/2012] [Indexed: 12/28/2022] Open
Abstract
Background Proteases regulate pathogenesis in apicomplexan parasites but investigations of proteases have been largely confined to the asexual stages of Plasmodium falciparum and Toxoplasma gondii. Thus, little is known about proteases in other Apicomplexa, particularly in the sexual stages. We screened the Eimeria tenella genome database for proteases, classified these into families and determined their stage specific expression. Results Over forty protease genes were identified in the E. tenella genome. These were distributed across aspartic (three genes), cysteine (sixteen), metallo (fourteen) and serine (twelve) proteases. Expression of at least fifteen protease genes was upregulated in merozoites including homologs of genes known to be important in host cell invasion, remodelling and egress in P. falciparum and/or T. gondii. Thirteen protease genes were specifically expressed or upregulated in gametocytes; five of these were in two families of serine proteases (S1 and S8) that are over-represented in the coccidian parasites, E. tenella and T. gondii, distinctive within the Apicomplexa because of their hard-walled oocysts. Serine protease inhibitors prevented processing of EtGAM56, a protein from E. tenella gametocytes that gives rise to tyrosine-rich peptides that are incorporated into the oocyst wall. Conclusion Eimeria tenella possesses a large number of protease genes. Expression of many of these genes is upregulated in asexual stages. However, expression of almost one-third of protease genes is upregulated in, or confined to gametocytes; some of these appear to be unique to the Coccidia and may play key roles in the formation of the oocyst wall, a defining feature of this group of parasites.
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Affiliation(s)
- Marilyn Katrib
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, Broadway, N.S.W. 2007, Australia
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12
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Munkhjargal T, AbouLaila M, Terkawi MA, Sivakumar T, Ichikawa M, Davaasuren B, Nyamjargal T, Yokoyama N, Igarashi I. Inhibitory effects of pepstatin A and mefloquine on the growth of Babesia parasites. Am J Trop Med Hyg 2012; 87:681-8. [PMID: 22890034 DOI: 10.4269/ajtmh.2012.12-0218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
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 < 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. Therefore, mefloquine may antagonize the actions of pepstatin A against babesiosis and aspartic proteases may play an important role in the asexual growth cycle of Babesia parasites.
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Affiliation(s)
- Tserendorj Munkhjargal
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, Japan.
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13
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Crystalloid body, refractile body and virus-like particles in Apicomplexa: what is in there? Parasitology 2012; 139:285-93. [PMID: 22217113 DOI: 10.1017/s0031182011002034] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The phylum of Apicomplexa comprises parasitic protozoa that share distinctive features such as the apical complex, the apicoplast, specialized cytoskeletal components and secretory organelles. Other unique cytoplasmic inclusions sharing similar features have been described in some representatives of Apicomplexa, although under different denominations. These are the crystalloid body, present for example in Cryptosporidium, Plasmodium and Cystoisospora; the refractile body in Eimeria and Lankesterella; and virus-like particles, also present in Eimeria and Cryptosporidium. Yet, the specific role of these cytoplasmic inclusions in the cell cycle of these protozoa is still unknown. Here, we discuss their morphology, possible inter-relatedness and speculate upon their function to bring these organelles back to the attention of the scientific community and promote new interest towards original research on these elusive structures.
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14
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A comparative transcriptome analysis reveals expression profiles conserved across three Eimeria spp. of domestic fowl and associated with multiple developmental stages. Int J Parasitol 2012; 42:39-48. [DOI: 10.1016/j.ijpara.2011.10.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 10/15/2011] [Accepted: 10/19/2011] [Indexed: 11/22/2022]
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15
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Lal K, Bromley E, Oakes R, Prieto JH, Sanderson SJ, Kurian D, Hunt L, Yates JR, Wastling JM, Sinden RE, Tomley FM. Proteomic comparison of four Eimeria tenella life-cycle stages: unsporulated oocyst, sporulated oocyst, sporozoite and second-generation merozoite. Proteomics 2009; 9:4566-76. [PMID: 19795439 DOI: 10.1002/pmic.200900305] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report the proteomes of four life-cycle stages of the Apicomplexan parasite Eimeria tenella. A total of 1868 proteins were identified, with 630, 699, 845 and 1532 found in early oocysts (unsporulated), late oocysts (sporulated), sporozoites and second-generation merozoites, respectively. A multidimensional protein identification technology shotgun approach identified 812 sporozoites, 1528 merozoites and all of the oocyst proteins, whereas 2-D gel proteomics identified 230 sporozoites and 98 merozoite proteins. Comparing the invasive stages, we find moving junction components RON2 in both, whereas AMA-1 and RON4 are found only in merozoites and AMA-2 and RON5 are only found in sporozoites, suggesting stage-specific moving junction proteins. During early oocyst to sporozoite development, refractile body and most "glideosome" proteins are found throughout, whereas microneme and most rhoptry proteins are only found after sporulation. Quantitative analysis indicates glycolysis and gluconeogenesis are the most abundant metabolic groups detected in all stages. The mannitol cycle "off shoot" of glycolysis was not detected in merozoites but was well represented in the other stages. However, in merozoites we find more protein associated with oxidative phosphorylation, suggesting a metabolic shift mobilising greater energy production. We find a greater abundance of protein linked to transcription, protein synthesis and cell cycle in merozoites than in sporozoites, which may be residual protein from the preceding massive replication during schizogony.
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Affiliation(s)
- Kalpana Lal
- The Division of Cell and Molecular Biology, Imperial College London, London, UK.
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16
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Wasmuth J, Daub J, Peregrín-Alvarez JM, Finney CAM, Parkinson J. The origins of apicomplexan sequence innovation. Genome Res 2009; 19:1202-13. [PMID: 19363216 DOI: 10.1101/gr.083386.108] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Apicomplexa are a group of phylogenetically related parasitic protists that include Plasmodium, Cryptosporidium, and Toxoplasma. Together they are a major global burden on human health and economics. To meet this challenge, several international consortia have generated vast amounts of sequence data for many of these parasites. Here, we exploit these data to perform a systematic analysis of protein family and domain incidence across the phylum. A total of 87,736 protein sequences were collected from 15 apicomplexan species. These were compared with three protein databases, including the partial genome database, PartiGeneDB, which increases the breadth of taxonomic coverage. From these searches we constructed taxonomic profiles that reveal the extent of apicomplexan sequence diversity. Sequences without a significant match outside the phylum were denoted as apicomplexan specialized. These were collated into 9134 discrete protein families and placed in the context of the apicomplexan phylogeny, identifying the putative origin of each family. Most apicomplexan families were associated with an individual genus or species. Interestingly, many genera-specific innovations were associated with specialized host cell invasion and/or parasite survival processes. Contrastingly, those families reflecting more ancestral relationships were enriched in generalized housekeeping functions such as translation and transcription, which have diverged within the apicomplexan lineage. Protein domain searches revealed 192 domains not previously reported in apicomplexans together with a number of novel domain combinations. We highlight domains that may be important to parasite survival.
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Affiliation(s)
- James Wasmuth
- Program in Molecular Structure and Function, Hospital for Sick Children, Toronto, Ontario M5G 2L3, Canada.
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17
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Ecker A, Bushell ESC, Tewari R, Sinden RE. Reverse genetics screen identifies six proteins important for malaria development in the mosquito. Mol Microbiol 2008; 70:209-20. [PMID: 18761621 PMCID: PMC2658712 DOI: 10.1111/j.1365-2958.2008.06407.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Transmission from the vertebrate host to the mosquito vector represents a major population bottleneck in the malaria life cycle that can successfully be targeted by intervention strategies. However, to date only about 25 parasite proteins expressed during this critical phase have been functionally analysed by gene disruption. We describe the first systematic, larger scale generation and phenotypic analysis of Plasmodium berghei knockout (KO) lines, characterizing 20 genes encoding putatively secreted proteins expressed by the ookinete, the parasite stage responsible for invasion of the mosquito midgut. Of 12 KO lines that were generated, six showed significant reductions in parasite numbers during development in the mosquito, resulting in a block in transmission of five KOs. While expression data, time point of essential function and mutant phenotype correlate well in three KOs defective in midgut invasion, in three KOs that fail at sporulation, maternal inheritance of the mutant phenotype suggests that essential function occurs during ookinete formation and thus precedes morphological abnormalities by several days.
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Affiliation(s)
- Andrea Ecker
- Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, UK.
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18
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Fetterer RH, Jenkins MC, Miska KB, Barfield RC. Characterization of the antigen SO7 during development of Eimeria tenella. J Parasitol 2008; 93:1107-13. [PMID: 18163345 DOI: 10.1645/ge-1171r.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The developmental expression of the antigen SO7, which has been previously shown to protect chickens against infection by several Eimeria species, was investigated. Using RT-PCR, mRNA for SO7 was found to be restricted primarily to unsporulated oocysts (0 hr). Western blot (WB) analysis with an antibody to recombinant SO7 (rbSO7) revealed expression of the protein from 6 to 72 hr (fully sporulated) of sporulation and in sporozoites (SZ). SO7 was absent in host-derived second-stage merozoites (MZ) and was present in culture-derived first-stage MZ but at a level of only 25% of that exhibited by SZ. During invasion of Madin-Darby bovine kidney (MDBK) cells by SZ in vitro, the level of SO7 within cells, as determined by WB analysis, remained relatively constant until 48 hr of development and then decreased by about 40% at the next time point (72 hr). The SO7 secreted into the culture media during in vitro development increased to a relative maximum at 48 hr and then decreased to about 20% of maximum at 72 hr. Immunostaining with anti-rbSO7 indicates that SO7 is highly concentrated in both refractile bodies (RB) of SZ, with some limited distribution in the apical complex. Anti-rbSO7 intensively stained the intracellular parasites and the first-stage schizonts during in vitro development of E. tenella in MDBK cells. Upon release from the schizonts, the first-stage merozoites stained with 1 or 2 bright spots typically at each end. The results suggest that SO7 is closely associated with the SZ RB and is developmentally regulated but may not play a direct role in cellular invasion.
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Affiliation(s)
- R H Fetterer
- Animal Parasitic Diseases Laboratory, Henry A. Wallace Beltsville Agricultural Research Center USDA/ARS, Beltsville, Maryland 20750, USA.
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19
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Shea M, Jäkle U, Liu Q, Berry C, Joiner KA, Soldati-Favre D. A Family of Aspartic Proteases and a Novel, Dynamic and Cell-Cycle-Dependent Protease Localization in the Secretory Pathway of Toxoplasma gondii. Traffic 2007; 8:1018-34. [PMID: 17547703 DOI: 10.1111/j.1600-0854.2007.00589.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aspartic proteases are important virulence factors in pathogens like HIV, Candida albicans or Plasmodium falciparum. We report here the identification of seven putative aspartic proteases, TgASP1 to TgASP7, in the apicomplexan parasite Toxoplasma gondii. Bioinformatic and phylogenetic analysis of the TgASPs and other aspartic proteases from related Apicomplexa suggests the existence of five distinct groups of aspartic proteases with different evolutionary lineages. The members of each group share predicted biological features that validate the phylogeny. TgASP1 is expressed in tachyzoites, the rapidly dividing asexual stage of T.gondii. We present the proteolytic maturation and subcellular localization of this protease through the cell cycle. TgASP1 shows a novel punctate localization associated with the secretory system in non-dividing cells, and relocalizes dramatically and unambiguously to the nascent inner membrane complex of daughter cells at replication, before coalescing again at the end of division.
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Affiliation(s)
- Michael Shea
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva, Switzerland
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20
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Labbé M, Péroval M, Bourdieu C, Girard-Misguich F, Péry P. Eimeria tenella enolase and pyruvate kinase: A likely role in glycolysis and in others functions. Int J Parasitol 2006; 36:1443-52. [PMID: 17030033 DOI: 10.1016/j.ijpara.2006.08.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 08/02/2006] [Accepted: 08/04/2006] [Indexed: 11/20/2022]
Abstract
Two cDNA codings for glycolytic enzymes were cloned from a cDNA library constructed from the schizont stage of the avian parasite Eimeria tenella. Enolase and pyruvate kinase cDNA were fully sequenced and compared with sequences of enzymes from other organisms. Although these enzymes were already detected in the sporozoite stage, their expression was enhanced during the first schizogony in accordance with the anaerobic conditions of this part of the life cycle of the parasite. Under activating conditions, microscopic observations suggest that these glycolytic enzymes were relocalised inside sporozoites and moreover were in part secreted. The enzymes were also localised at the apex of the first generation of merozoites. Enolase was partly observed inside the nucleus of sporozoites and schizonts. Taken together, these results suggest that glycolytic enzymes not only have a function in glycolysis during anaerobic intracellular stages but may also participate in the invasion process and, for enolase, in the control of gene regulation.
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Affiliation(s)
- Marie Labbé
- Unité de Virologie et Immunologie Moléculaires, INRA Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
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21
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de Venevelles P, François Chich J, Faigle W, Lombard B, Loew D, Péry P, Labbé M. Study of proteins associated with the Eimeria tenella refractile body by a proteomic approach. Int J Parasitol 2006; 36:1399-407. [PMID: 16959255 DOI: 10.1016/j.ijpara.2006.06.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 06/19/2006] [Accepted: 06/23/2006] [Indexed: 11/21/2022]
Abstract
Refractile bodies (RB), whose function is still unknown, are specific structures of Eimeriidae parasites. In order to study their proteome, RB were purified from Eimeria tenella sporozoites by a new procedure using a reversible fixation followed by centrifugation. RB proteins were resolved by two-dimensional electrophoresis. Around 76 and 89 spots were detected on RB two-dimensional gels using gradients in the 3-10 and 4-7 range, respectively. RB proteins were located mainly between pH 5 and 7. RB gels were then compared with previously established maps of the entire sporozoite proteome. Proteins appearing in new spots were identified by mass spectrometry. Thirty protein isoforms were located in RB. Added to the already known RB proteins such as Eimepsin and SO7', the new RB proteins were defined as haloacid dehalogenase, hydrolase, subtilase, lactacte dehydrogenase or ubiquitin family proteins. The RB proteome analysis confirmed the hypothesis that this structure is a reservoir for proteins necessary to invasion but also suggests that RB have energetic and metabolic functions.
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Affiliation(s)
- Patrick de Venevelles
- Unité de Virologie et Immunologie Moléculaires UR892, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France
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22
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Labbé M, de Venevelles P, Girard-Misguich F, Bourdieu C, Guillaume A, Péry P. Eimeria tenella microneme protein EtMIC3: identification, localisation and role in host cell infection. Mol Biochem Parasitol 2005; 140:43-53. [PMID: 15694485 DOI: 10.1016/j.molbiopara.2004.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/26/2004] [Accepted: 12/08/2004] [Indexed: 11/26/2022]
Abstract
The gene coding for Eimeria tenella protein EtMIC3 was cloned by screening a sporozoite cDNA library with two independent monoclonal antibodies raised against the oocyst stage. The deduced sequence of EtMIC3 is 988 amino acids long. The protein presents seven repeats in tandem, with four highly conserved internal repeats and three more divergent external repeats. Each repeat is characterised by a tyrosine kinase phosphorylation site, WRCY, and a reminiscent motif of the thrombospondin1 (TSP1)-type I domain, CXXXCG. The protein EtMIC3 is localised at the apex of free parasite stages. It is not detected in the early intracellular parasite stage but is synthesised in mature schizonts. Secretion of the protein is induced when sporozoites are incubated in complete medium at 41 degrees C. Strangely enough, the two independent mAb that allow cloning of EtMIC3 interfere with parasitic growth in different ways. One is able to inhibit parasite invasion whereas the other inhibits development. Expression and localisation of the protein EtMIC3 are consistent with a protein involved in the invasion process as is expected for a microneme protein.
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Affiliation(s)
- M Labbé
- Laboratoire de Virologie et Immunologie Moléculaires INRA, 78352 Jouy-en-Josas, France.
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23
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Dowse T, Soldati D. Host cell invasion by the apicomplexans: the significance of microneme protein proteolysis. Curr Opin Microbiol 2004; 7:388-96. [PMID: 15358257 DOI: 10.1016/j.mib.2004.06.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Intracellular life-style has been adopted by many pathogens as a successful immune evasion mechanism. To gain entry to a large variety of host cells and to establish an intracellular niche, Toxoplasma gondii and other apicomplexans rely on an active process distinct from phagocytosis. Calcium-regulated secretion of microneme proteins and parasite actin polymerization together with the action of at least one myosin motor act in concert to generate the gliding motility necessary to propel the parasite into host cells. During this active penetration, host cell transmembrane proteins are excluded from the forming parasitophorous vacuole hence conferring the resistance to acidification and degradative fusion. Apicomplexans possess a large repertoire of microneme proteins that contribute to invasion, but their precise role and the level of functional redundancy remain to be evaluated. Remarkably, most microneme proteins are proteolytically cleaved during biogenesis and post-exocytosis. The significance of the processing events and the identification of the proteases implicated are the object of intensive investigations. These proteases may constitute potential drug targets for intervention against malaria and other diseases caused by these parasites.
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Affiliation(s)
- Timothy Dowse
- Department of Biological Sciences, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
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24
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Mele R, Gomez Morales MA, Tosini F, Pozio E. Indinavir reduces Cryptosporidium parvum infection in both in vitro and in vivo models. Int J Parasitol 2003; 33:757-64. [PMID: 12814654 DOI: 10.1016/s0020-7519(03)00093-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of highly active antiretroviral therapy in persons with acquired immunodeficiency syndrome has reduced the prevalence of infection with Cryptosporidium parvum and the length and severity of its clinical course. This effect has in most cases been attributed to the recovery of the host immunity; however, some works suggest that human immunodeficiency virus protease inhibitors, indinavir in particular, which is one of the human immunodeficiency virus protease inhibitors used in highly active antiretroviral therapy, may be capable of controlling Microsporidia and Cryptosporidium infections, which are refractory to other treatments. The objective of the present study was to investigate the effect of human immunodeficiency virus protease inhibitors on C. parvum infections. Since preliminary experiments using ritonavir, saquinavir, and indinavir showed a drastic reduction of C. parvum infection both in vivo (neonatal Balb/c mice) and in vitro (human ileocecal adenocarcinoma tumour cell line) models, indinavir alone was tested in successive experiments. In vitro, the treatment of the sporulated oocysts with different concentrations of indinavir reduced the percentage of human ileocecal adenocarcinoma tumour cell line infected cells in a dose-dependent manner. For established infection, the treatment with 50 microM of indinavir decreased the percentage of infected cells in a time-dependent manner. In vivo, mice treated with indinavir at the same time they were infected with the oocysts showed a 93% reduction in the number of oocysts present in the entire intestinal contents and a 91% reduction in the number of intracellular parasites in the ileum. For established infection, indinavir treatment reduced the number of oocysts in the entire intestinal content by about 50% and the number of intracellular parasites in the ileum by about 70%. These data show that indinavir directly interferes with the cycle of C. parvum, resulting in a marked reduction in oocyst shedding and in the number of intracellular parasites. Protease inhibitors could be considered as good candidates for the treatment of cyptosporidiosis in immunosuppressed persons.
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Affiliation(s)
- R Mele
- Laboratory of Parasitology, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
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25
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Abstract
Coccidia provide a rich hunting ground for drug-designers, as there are significant biochemical differences between the parasites and their hosts. Recent years have brought the discovery of the plastid and its possible metabolic machinery, characterisation of acidocalcisomes, reports on the apparent absence from some coccidia of a typical mitochondrion, and the discovery of the mannitol cycle and shikimate pathway in the parasites. Moreover, modern technologies such as genomics and proteomics are bringing new insights into the biochemistry of coccidia and highlighting possible drug targets in abundance. A major issue for would-be drug discoverers is to decide upon the targets to prioritise. This review provides an update on recent findings on how coccidia differ biochemically from vertebrates. It includes discoveries within coccidian parasites themselves but also uses findings in Plasmodium to provide an overview of biochemical features that may be characteristics of many apicomplexan parasites and so potential targets for broad-spectrum drugs.
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Affiliation(s)
- G H Coombs
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, G12 8QQ, Glasgow, UK.
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Coombs GH, Goldberg DE, Klemba M, Berry C, Kay J, Mottram JC. Aspartic proteases of Plasmodium falciparum and other parasitic protozoa as drug targets. Trends Parasitol 2001; 17:532-7. [PMID: 11872398 DOI: 10.1016/s1471-4922(01)02037-2] [Citation(s) in RCA: 231] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
All parasitic protozoa contain multiple proteases, some of which are attracting attention as drug targets. Aspartic proteases are already the targets of some clinically useful drugs (e.g. chemotherapy of HIV infection) and a variety of factors make these enzymes appealing to those seeking novel antiparasite therapies. This review provides a critical analysis of the current knowledge on Plasmodium aspartic proteases termed plasmepsins, proposes a definitive nomenclature for this group of enzymes, and compares these enzymes with aspartic proteases of humans and other parasitic protozoa. The present status of attempts to obtain specific inhibitors of the parasite enzymes that will be useful as drugs is outlined and suggestions for future research priorities are proposed.
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Affiliation(s)
- G H Coombs
- University of Glasgow, G12 8QQ, Glasgow, UK.
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27
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Abstract
We have compiled a comprehensive list of the articles published in the year 2000 that describe work employing commercial optical biosensors. Selected reviews of interest for the general biosensor user are highlighted. Emerging applications in areas of drug discovery, clinical support, food and environment monitoring, and cell membrane biology are emphasized. In addition, the experimental design and data processing steps necessary to achieve high-quality biosensor data are described and examples of well-performed kinetic analysis are provided.
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Affiliation(s)
- R L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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28
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Jean L, Péry P, Dunn P, Bumstead J, Billington K, Ryan R, Tomley F. Genomic organisation and developmentally regulated expression of an apicomplexan aspartyl proteinase. Gene 2001; 262:129-36. [PMID: 11179676 DOI: 10.1016/s0378-1119(00)00543-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The cDNA for an aspartyl proteinase, termed eimepsin, was isolated from an Eimeria tenella sporulated oocyst library and the deduced amino acid sequence found to be almost identical to a previously described aspartyl proteinase from E. acervulina (97.4% amino acid identity). An E. tenella cosmid clone covering the entire eimepsin gene was cloned and characterised. Sequencing revealed that the eimepsin gene spans 2.9 kb and consists of 18 exons and 17 introns. The 5' flanking region sequence of the gene contains a putative transcriptional promoter sequence (TATAAA box) and three potential transcription initiator sites (Inr sites). Expression of eimepsin at the mRNA and protein level is developmentally regulated during oocyst sporulation. The eimepsin transcript was detected in unsporulated oocysts and increased in abundance during the early part of sporulation when the oocyst undergoes nuclear division and blast formation. Thereafter, the level of the eimepsin transcript decreases and in the excysted sporozoite, no eimepsin-specific RNA was detected. Expression of eimepsin lags behind transcript expression by some hours, and the protein accumulates in the oocyst during sporocyst and sporozoite formation.
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Affiliation(s)
- L Jean
- Unité de Virologie et d'Immunologie Moléculaires, INRA, Domaine de Vilvert, 78352 Jouy-en-Josas, cedex, France
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