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Ozubek S, Ulucesme MC, Bastos RG, Alzan HF, Laughery JM, Suarez CE, Aktas M. Experimental infection of non-immunosuppressed and immunosuppressed goats reveals differential pathogenesis of Babesia aktasi n. sp. Front Cell Infect Microbiol 2023; 13:1277956. [PMID: 38029260 PMCID: PMC10651745 DOI: 10.3389/fcimb.2023.1277956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Babesiosis is an acute and persistent tick-borne disease caused by protozoan parasites of the genus Babesia. These hemoparasites affect vertebrates globally, resulting in symptoms such as high fever, anemia, jaundice, and even death. Advancements in molecular parasitology revealed new Babesia species/genotypes affecting sheep and goats, including Babesia aktasi n. sp., which is highly prevalent in goats from Turkiye's Mediterranean region. The objective of this study was to investigate the pathogenesis of B. aktasi infection in immunosuppressed (n=7) and non-immunosuppressed (n=6) goats. These animals were experimentally infected with fresh B. aktasi infected blood, and their clinical signs, hematological and serum biochemical parameters were monitored throughout the infection. The presence of parasites in the blood of immunosuppressed goats was detected by microscopic examination between 4 and 6 days after infection, accompanied by fever and increasing parasitemia. Goats that succumbed acute disease exhibited severe clinical signs, such as anemia, hemoglobinuria, and loss of appetite. However, the goats that survived showed milder clinical signs. In the non-immunosuppressed group, piroplasm forms of B. aktasi were observed in the blood within 2-5 days after inoculation, but with low (0.01-0.2%) parasitemia. Although these goats showed loss of appetite, typical signs of babesiosis were absent except for increased body temperature. Hematological analysis revealed significant decreases in the levels of red blood cells, leukocytes and platelet values post-infection in immunosuppressed goats, while no significant hematological changes were observed in non-immunosuppressed goats. In addition, serum biochemical analysis showed elevated transaminase liver enzymes levels, decreased glucose, and lower total protein values in the immunosuppressed group post-infection. Babesia aktasi, caused mild disease with minor clinical symptoms in non-immunosuppressed goats. However, in immunosuppressed goats, it exhibited remarkable pathogenicity, leading to severe clinical infections and death. In conclusion, this study provides valuable insights into the pathogenicity of the parasite and will serve as a foundation for future research aimed at developing effective prevention and control strategies against babesiosis in small ruminants. Further research is required to investigate the pathogenicity of B. aktasi in various goat breeds, other potential hosts, the vector ticks involved, and its presence in natural reservoirs.
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Affiliation(s)
- Sezayi Ozubek
- Department of Parasitology, Faculty of Veterinary Medicine, University of Firat, Elazig, Türkiye
| | - Mehmet Can Ulucesme
- Department of Parasitology, Faculty of Veterinary Medicine, University of Firat, Elazig, Türkiye
| | - Reginaldo G. Bastos
- Animal Disease Research Unit, United States Department of Agricultural (USDA), Agricultural Research Service, Pullman, WA, United States
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Heba F. Alzan
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- Parasitology and Animal Diseases Department, National Research Center, Giza, Egypt
| | - Jacob M. Laughery
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Carlos E. Suarez
- Animal Disease Research Unit, United States Department of Agricultural (USDA), Agricultural Research Service, Pullman, WA, United States
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Munir Aktas
- Department of Parasitology, Faculty of Veterinary Medicine, University of Firat, Elazig, Türkiye
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Wang J, Chen K, Ren Q, Zhang S, Yang J, Wang Y, Nian Y, Li X, Liu G, Luo J, Yin H, Guan G. Comparative genomics reveals unique features of two Babesia motasi subspecies: Babesia motasi lintanensis and Babesia motasi hebeiensis. Int J Parasitol 2023; 53:265-283. [PMID: 37004737 DOI: 10.1016/j.ijpara.2023.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 02/05/2023] [Accepted: 02/12/2023] [Indexed: 04/03/2023]
Abstract
Parasites of the Babesia genus are prevalent worldwide and infect a wide diversity of domestic animals and humans. Herein, using Oxford Nanopore Technology and Illumina sequencing technologies, we sequenced two Babesia sub-species, Babesia motasi lintanensis and Babesia motasi hebeiensis. We identified 3,815 one-to-one ortholog genes that are specific to ovine Babesia spp. Phylogenetic analysis reveals that the two B. motasi subspecies form a distinct clade from other Piroplasma spp. Consistent with their phylogenetic position, comparative genomic analysis reveals that these two ovine Babesia spp. share higher colinearity with Babesia bovis than with Babesia microti. Concerning the speciation date, B. m. lintanensis split from B. m. hebeiensis approximately 17 million years ago. Genes correlated to transcription, translation, protein modification and degradation, as well as differential/specialized gene family expansions in these two subspecies may favor adaptation to vertebrate and tick hosts. The close relationship between B. m. lintanensis and B. m. hebeiensis is underlined by a high degree of genomic synteny. Compositions of most invasion, virulence, development, and gene transcript regulation-related multigene families, including spherical body protein, variant erythrocyte surface antigen, glycosylphosphatidylinositol anchored proteins, and transcription factor Apetala 2 genes, is largely conserved, but in contrast to this conserved situation, we observe major differences in species-specific genes that may be involved in multiple functions in parasite biology. For the first time in Babesia spp., we find abundant fragments of long terminal repeat-retrotransposons in these two species. We provide fundamental information to characterize the genomes of B. m. lintanensis and B. m. hebeiensis, providing insights into the evolution of B. motasi group parasites.
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Affiliation(s)
- Jinming Wang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
| | - Kai Chen
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Qiaoyun Ren
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
| | - Shangdi Zhang
- Department of Clinical Laboratory, The Second Hospital of Lanzhou University, Lanzhou, China.
| | - Jifei Yang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
| | - Yanbo Wang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China; Department of Clinical Laboratory, The Second Hospital of Lanzhou University, Lanzhou, China.
| | - Yueli Nian
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China; Department of Clinical Laboratory, The Second Hospital of Lanzhou University, Lanzhou, China.
| | - Xiaoyun Li
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
| | - Guangyuan Liu
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
| | - Jianxun Luo
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
| | - Hong Yin
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China; Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou 225009, China.
| | - Guiquan Guan
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Lanzhou, Gansu 730046, China.
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The Piroplasmida Babesia, Cytauxzoon, and Theileria in farm and companion animals: species compilation, molecular phylogeny, and evolutionary insights. Parasitol Res 2022; 121:1207-1245. [DOI: 10.1007/s00436-022-07424-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/02/2022] [Indexed: 12/13/2022]
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Martins-Duarte ÉS, Sheiner L, Reiff SB, de Souza W, Striepen B. Replication and partitioning of the apicoplast genome of Toxoplasma gondii is linked to the cell cycle and requires DNA polymerase and gyrase. Int J Parasitol 2021; 51:493-504. [PMID: 33581138 PMCID: PMC8113025 DOI: 10.1016/j.ijpara.2020.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/30/2020] [Accepted: 11/08/2020] [Indexed: 10/26/2022]
Abstract
Apicomplexans are the causative agents of numerous important infectious diseases including malaria and toxoplasmosis. Most of them harbour a chloroplast-like organelle called the apicoplast that is essential for the parasites' metabolism and survival. While most apicoplast proteins are nuclear encoded, the organelle also maintains its own genome, a 35 kb circle. In this study we used Toxoplasma gondii to identify and characterise essential proteins involved in apicoplast genome replication and to understand how apicoplast genome segregation unfolds over time. We demonstrated that the DNA replication enzymes Prex, DNA gyrase and DNA single stranded binding protein localise to the apicoplast. We show in knockdown experiments that apicoplast DNA Gyrase A and B, and Prex are required for apicoplast genome replication and growth of the parasite. Analysis of apicoplast genome replication by structured illumination microscopy in T. gondii tachyzoites showed that apicoplast nucleoid division and segregation initiate at the beginning of S phase and conclude during mitosis. Thus, the replication and division of the apicoplast nucleoid is highly coordinated with nuclear genome replication and mitosis. Our observations highlight essential components of apicoplast genome maintenance and shed light on the timing of this process in the context of the overall parasite cell cycle.
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Affiliation(s)
- Érica S Martins-Duarte
- Laboratório de Quimioterapia de Protozoários Egler Chiari, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Núcleo de Biologia Estrutural e Bioimagens (CENABIO) - Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro, RJ, Brazil.
| | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, 120 University Place Glasgow, United Kingdom
| | - Sarah B Reiff
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Wanderley de Souza
- Núcleo de Biologia Estrutural e Bioimagens (CENABIO) - Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro, RJ, Brazil; Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Boris Striepen
- Department of Cellular Biology, University of Georgia, Athens, GA, USA; Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA. USA
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Wang X, Wang J, Liu J, Liu A, He X, Xiang Q, Li Y, Yin H, Luo J, Guan G. Insights into the phylogenetic relationships and drug targets of Babesia isolates infective to small ruminants from the mitochondrial genomes. Parasit Vectors 2020; 13:378. [PMID: 32727571 PMCID: PMC7391622 DOI: 10.1186/s13071-020-04250-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/20/2020] [Indexed: 01/22/2023] Open
Abstract
Background Babesiosis, a tick-borne disease caused by protozoans of the genus Babesia, is widespread in subtropical and tropical countries. Mitochondria are essential organelles that are responsible for energy transduction and metabolism, calcium homeostasis and cell signaling. Mitochondrial genomes could provide new insights to help elucidate and investigate the biological features, genetic evolution and classification of the protozoans. Nevertheless, there are limited data on the mitochondrial genomes of ovine Babesia spp. in China. Methods Herein, we sequenced, assembled and annotated the mitochondrial genomes of six ovine Babesia isolates; analyzed the genome size, gene content, genome structure and cytochrome b (cytb) amino acid sequences and performed comparative mitochondrial genomics and phylogenomic analyses among apicomplexan parasites. Results The mitochondrial genomes range from 5767 to 5946 bp in length with a linear form and contain three protein-encoding genes, cytochrome c oxidase subunit 1 (cox1), cytochrome c oxidase subunit 3 (cox3) and cytb, six large subunit rRNA genes (LSU) and two terminal inverted repeats (TIR) on both ends. The cytb gene sequence analysis indicated the binding site of anti-Babesia drugs that targeted the cytochrome bc1 complex. Babesia microti and Babesia rodhaini have a dual flip-flop inversion of 184–1082 bp, whereas other Babesia spp. and Theileria spp. have one pair of TIRs, 25–1563 bp. Phylogenetic analysis indicated that the six ovine Babesia isolates were divided into two clades, Babesia sp. and Babesia motasi. Babesia motasi isolates were further separated into two small clades (B. motasi Hebei/Ningxian and B. motasi Tianzhu/Lintan). Conclusions The data provided new insights into the taxonomic relationships and drug targets of apicomplexan parasites. ![]()
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Affiliation(s)
- Xiaoxing Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Jinming Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Junlong Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Aihong Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Xin He
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Quanjia Xiang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Youquan Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Hong Yin
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, 225009, People's Republic of China
| | - Jianxun Luo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
| | - Guiquan Guan
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Science, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China.
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Liu Q, Yu L, Jiang F, Li M, Zhan X, Huang Y, Wang S, Du X, He L, Zhao J. Annotation and characterization of Babesia gibsoni apicoplast genome. Parasit Vectors 2020; 13:209. [PMID: 32317011 PMCID: PMC7175588 DOI: 10.1186/s13071-020-04065-7] [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: 10/31/2019] [Accepted: 04/09/2020] [Indexed: 11/10/2022] Open
Abstract
Background Babesia gibsoni is an apicomplexan parasite transmitted by ticks, which can infect canine species and cause babesiosis. The apicoplast is an organelle associated with isoprenoids metabolism, is widely present in apicomplexan parasites, except for Cryptosporidium. Available data indicate that the apicoplast is essential for the survival of apicomplexan parasites. Methods Here, the apicoplast genome of B. gibsoni was investigated by high-throughput genome sequencing, bioinformatics analysis, and conventional PCR. Results The apicoplast genome of B. gibsoni-Wuhan strain (B. gibsoni-WH) consists of a 28.4 kb circular molecule, with A + T content of 86.33%, similar to that of B. microti. Specifically, this genome encodes genes involved in maintenance of the apicoplast DNA, transcription, translation and maturation of organellar proteins, which contains 2 subunits of ribosomal RNAs, 17 ribosomal proteins, 1 EF-Tu elongation factor (tufA), 5 DNA-dependent RNA polymerase beta subunits, 2 Clp protease chaperones, 23 tRNA genes and 5 unknown open reading frames (hypothetical proteins). Phylogenetic analysis revealed high similarity of B. gibsoni apicoplast genome to that of B. orientalis and B. bovis. Conclusions To our knowledge, this is the first report of annotation and characterization of B. gibsoni-WH apicoplast genome. The results will facilitate the development of new anti-Babesia drug targets.![]()
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Affiliation(s)
- Qin Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China
| | - Long Yu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China
| | - Fan Jiang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Muxiao Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China
| | - Xueyan Zhan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China
| | - Yuan Huang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China
| | - Sen Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China
| | - Xiaoyong Du
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Lan He
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. .,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China. .,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, 430070, Hubei, China.
| | - Junlong Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, 430070, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, 430070, Hubei, China
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There Is Treasure Everywhere: Reductive Plastid Evolution in Apicomplexa in Light of Their Close Relatives. Biomolecules 2019; 9:biom9080378. [PMID: 31430853 PMCID: PMC6722601 DOI: 10.3390/biom9080378] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/16/2019] [Accepted: 08/16/2019] [Indexed: 02/05/2023] Open
Abstract
The phylum Apicomplexa (Alveolates) comprises a group of host-associated protists, predominately intracellular parasites, including devastating parasites like Plasmodium falciparum, the causative agent of malaria. One of the more fascinating characteristics of Apicomplexa is their highly reduced (and occasionally lost) remnant plastid, termed the apicoplast. Four core metabolic pathways are retained in the apicoplast: heme synthesis, iron–sulfur cluster synthesis, isoprenoid synthesis, and fatty acid synthesis. It has been suggested that one or more of these pathways are essential for plastid and plastid genome retention. The past decade has witnessed the discovery of several apicomplexan relatives, and next-generation sequencing efforts are revealing that they retain variable plastid metabolic capacities. These data are providing clues about the core genes and pathways of reduced plastids, while at the same time further confounding our view on the evolutionary history of the apicoplast. Here, we examine the evolutionary history of the apicoplast, explore plastid metabolism in Apicomplexa and their close relatives, and propose that the differences among reduced plastids result from a game of endosymbiotic roulette. Continued exploration of the Apicomplexa and their relatives is sure to provide new insights into the evolution of the apicoplast and apicomplexans as a whole.
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