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Weng M, Zhang X, Xin Z, Xue S, Zhang Q, Li A, Zhang J. Morphological characterization and genetic diversity of a new microsporidium, Neoflabelliforma dubium n. sp. from the adipose tissue of Diaphanosoma dubium (Crustacea: Sididae). Front Cell Infect Microbiol 2023; 13:1125394. [PMID: 36779184 PMCID: PMC9911548 DOI: 10.3389/fcimb.2023.1125394] [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: 12/16/2022] [Accepted: 01/16/2023] [Indexed: 01/28/2023] Open
Abstract
We reported a new microsporidium Neoflabelliforma dubium n. sp. from the adipose tissue of Diaphanosoma dubium in China. The infected daphnids generally appeared opaque due to the presence of numerous spore aggregates located in the adipose tissue. All developmental stages were in direct contact with the host cell cytoplasm. Multinucleate sporogonial plasmodia developed into uninucleate sporoblasts by rosette-like fashion. Mature spores were pyriform and monokaryotic, measuring 4.02 ± 0.24 (3.63-4.53) µm long and 2.27 ± 0.15 (2.12-2.57) µm wide (N = 40). The polaroplast was bipartite with a tightly packed anterior lamellae and a loosely aligned posterior lamellae. Isofilar polar filament was coiled 9-11 turns and arranged in 2-3 rows. The phylogenetic analysis based on the obtained SSU rDNA sequence indicated that the N. dubium n. sp. clustered with the freshwater oligochaete-infecting N. aurantiae to form an independent monophyletic group, positioned at the base of Clade 4. In addition, we analyzed the genetic diversity in three N. dubium n. sp. isolates based on the rDNA (SSU rDNA, ITS and LSU rDNA) and Rpb1 gene. The genetic variation among the rDNA sequences was not distinct, however, high nucleotide diversity could be observed in Rpb1 gene, and a wide variety of Rpb1 haplotypes were identified within each isolate. Genetic recombination detected in the Rpb1 sequences presumes cryptic sexual process occurring in N. dubium n. sp. Statistical evolutionary analyses further indicated that the purifying selection eliminated mutations in the Rpb1 gene.
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Affiliation(s)
- Meiqi Weng
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xintong Zhang
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Zhaozhe Xin
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Sijia Xue
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Qianqian Zhang
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Aihua Li
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jinyong Zhang
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong, China
- *Correspondence: Jinyong Zhang,
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Kiani-Azad K, Bagheri M, Sadeghi M, Nematollahian S, Zahmatkesh A, Moharrami M, Miraie-Ashtiani SR. Molecular Characterization of a New Nosema bombycis Strain Detected in Iranian Silkworm Farms. Acta Parasitol 2022; 67:1364-1371. [PMID: 35857274 DOI: 10.1007/s11686-022-00592-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 07/01/2022] [Indexed: 11/01/2022]
Abstract
PURPOSE Pebrine as the most dangerous disease of silkworm mostly caused by Nosema species has caused huge economic losses. There is no information on the species and the genomic sequences of the pebrine-causing microsporidia in Iran. METHODS In the present research, we tried to determine the sequences of two regions of rDNA using molecular methods. First, infected larvae and mother moths were collected from several farms in the north of Iran for identification and molecular characterization of microsporidian isolates. After extracting the spores and genomic DNA from the collected samples, two fragments of internal transcribed spacer (ITS) rDNA and small subunit (SSU) rDNA were amplified and sequenced, and registered in NCBI database and then, the phylogenetic tree was drawn. RESULTS Results showed the obtained sequences (ITS rDNA: Accession No. MZ322002 and SSU rDNA: Accession No. MZ314703) represent a new strain of Nosema bombycis, which differs from the sequences deposited in the NCBI. CONCLUSION The new N. bombycis strain identified in our study will help in control and management of the pebrine disease by specific detection of the infectious agent.
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Affiliation(s)
- Kimia Kiani-Azad
- Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, 31976-19751, Iran.,Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Masoumeh Bagheri
- Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, 31976-19751, Iran.
| | - Mostafa Sadeghi
- Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Shahla Nematollahian
- Iran Silkworm Research Center (ISRC) Agricultural Research, Education and Extension Organization (AREEO), Rasht, Iran
| | - Azadeh Zahmatkesh
- Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, 31976-19751, Iran
| | - Mojtaba Moharrami
- Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, 31976-19751, Iran
| | - Seyed Reza Miraie-Ashtiani
- Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
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Weng M, Xie D, Zhang Q, Li A, Zhang J. First report of Ovipleistophora ovariae and O. diplostomuri in China provides new insights into the intraspecific genetic variation and extends their distribution. Parasitology 2022; 149:314-324. [PMID: 35264262 PMCID: PMC11010532 DOI: 10.1017/s0031182021001852] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/07/2021] [Accepted: 10/17/2021] [Indexed: 11/07/2022]
Abstract
Microsporidia of the genus Ovipleistophora are generally parasites of fishes and aquatic crustaceans. In the current study, Ovipleistophora diplostomuri and O. ovariae were firstly reported from Culter alburnus and Xenocypris argentea and Parabramis pekinensis, respectively. Both of them exclusively infected fish ovary and were morphologically, ultrastructurally and genetically characterized. Sporogony occurred in direct contact with the host cell cytoplasm and sporophorous vesicles were not observed for the new isolates of these two Ovipleistophora species. Spores of O. ovariae were for the first time observed to be dimorphic. Genetic analysis indicated that the genetic variation in the ITS and LSU sequences was distinct among between-host O. diplostomuri isolates. High sequence variation in ITS sequence suggests that it can be a reliable molecular marker to explore the population genetics of O. diplostomuri. This is the first report of these two Ovipleistophora species in China which extends their host and geographical range.
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Affiliation(s)
- Meiqi Weng
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, 266237Qingdao, China
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing10049, China
| | - Derong Xie
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, 266237Qingdao, China
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing10049, China
| | - Qianqian Zhang
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Aihua Li
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Jinyong Zhang
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, 266237Qingdao, China
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Development and optimization of a TaqMan assay for Nosema bombycis, causative agent of pébrine disease in Bombyx mori silkworm, based on the β-tubulin gene. J Microbiol Methods 2021; 186:106238. [PMID: 33991586 DOI: 10.1016/j.mimet.2021.106238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/09/2021] [Accepted: 05/11/2021] [Indexed: 11/20/2022]
Abstract
"Pébrine" is a devastating disease of Bombyx mori silkworms that is highly contagious and can completely destroy an entire crop of silkworms and is thus a serious threat for the viability and profitability of sericulture. The disease is most commonly attributed to microsporidians of the genus Nosema, which are obligate intracellular parasites that are transmitted through spores. Nosema infections in silkworms are diagnosed primarily through light microscopy, which is labour intensive and less reliable, sensitive, and specific than PCR-based techniques. Here, we present the development and optimization of a new TaqMan based assay targeting the β-tubulin gene in the pébrine disease causing agent Nosema bombycis in silkworms. The assay displayed excellent quantification linearity over multiple orders of magnitude of target amounts and a limit of detection (LOD) of 6.9 × 102 copies of target per reaction. The method is highly specific to N. bombycis with no cross-reactivity to other Nosema species commonly infecting wild silkworms. This specificity was due to three nucleotides in the probe-binding region unique to N. bombycis. The assay demonstrated a high reliability with a Coefficient of variation (CV) <5% for both intra-assay and inter-assay variability. The assay was used to trace experimental N. bombycis infection of silkworm larvae, in the fat body, midgut and ovary tissues, through pupation and metamorphosis to the emerging female moth, and her larval off-spring, confirming the vertical transmission of N. bombycis in silkworms. The TaqMan assay revealed a gradual increase in infection levels in the post-infection samples. The assay is reliable and simple to implement and can be a suitable complement to microscopy for routine diagnostics and surveillance in silkworm egg production centres with appropriate infrastructure.
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Ding S, Huang W, Qin Q, Tang J, Liu H. Genotype Identification and Phylogenetic Analysis of Enterocytozoon bieneusi Isolates from Stool Samples of Diarrheic Children. J Parasitol 2018; 104:297-301. [PMID: 29457962 DOI: 10.1645/17-108] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Among approximately 14 human-pathogenic microsporidian species, Enterocytozoon bieneusi is the most common. It can inhabit the small intestines, causing chronic diarrhea and wasting syndrome. Prevalence and genotype data for E. bieneusi in humans is available for only a few provinces of China. In the current study, 93 fecal specimens were collected from diarrheic children in Chongqing. Polymerase chain reaction amplification and sequencing of the internal transcribed spacer ( ITS) region of the E. bieneusi rDNA sequence identified 11 (11.83%) positive specimens. Among them, 8 (8.60%) are from patients of ages ranging from 2 mo to 6 yr old and 3 (3.23%) from patients 7 to 11 yr old. In total, 6 genotypes (4 novel genotypes and 2 known genotypes) were identified in this study. Phylogenetic analysis showed that all the genotypes identified in the present study belong to group 1, which previously has been described as a zoonotic group. This could mean these infections were acquired zoonotically, and it may be prudent to warn those people having close contact with animals of this potential risk.
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Affiliation(s)
- Songtao Ding
- 1 Department of Cell Biology and Genetics, Experimental Teaching Center, Chongqing Medical University, No. 1, Medical College Road, Yuzhong District, Chongqing 400016, People's Republic of China
| | - Wei Huang
- 2 Chongqing Center for Disease Control and Prevention, Chongqing, 400042, People's Republic of China
| | - Qizhong Qin
- 1 Department of Cell Biology and Genetics, Experimental Teaching Center, Chongqing Medical University, No. 1, Medical College Road, Yuzhong District, Chongqing 400016, People's Republic of China
| | - Jun Tang
- 1 Department of Cell Biology and Genetics, Experimental Teaching Center, Chongqing Medical University, No. 1, Medical College Road, Yuzhong District, Chongqing 400016, People's Republic of China
| | - Handeng Liu
- 1 Department of Cell Biology and Genetics, Experimental Teaching Center, Chongqing Medical University, No. 1, Medical College Road, Yuzhong District, Chongqing 400016, People's Republic of China
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Hajek AE, Solter LF, Maddox JV, Huang WF, Estep AS, Krawczyk G, Weber DC, Hoelmer KA, Sanscrainte ND, Becnel JJ. Nosema maddoxi sp. nov. (Microsporidia, Nosematidae), a Widespread Pathogen of the Green Stink Bug Chinavia hilaris (Say) and the Brown Marmorated Stink Bug Halyomorpha halys (Stål). J Eukaryot Microbiol 2017; 65:315-330. [PMID: 28984006 DOI: 10.1111/jeu.12475] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/21/2017] [Accepted: 08/11/2017] [Indexed: 11/28/2022]
Abstract
We describe a unique microsporidian species that infects the green stink bug, Chinavia hilaris; the brown marmorated stink bug, Halyomorpha halys; the brown stink bug, Euschistus servus; and the dusky stink bug, Euschistus tristigmus. All life stages are unikaryotic, but analysis of the consensus small subunit region of the ribosomal gene places this microsporidium in the genus Nosema, which historically has been characterized by diplokaryotic life stages. It is also characterized by having the reversed arrangement of the ribosomal gene (LSU -ITS- SSU) found in species within the "true Nosema" clade. This microsporidium is apparently Holarctic in distribution. It is present in H. halys both where it is native in Asia and where it is invasive in North America, as well as in samples of North American native C. hilaris collected prior to the introduction of H. halys from Asia. Prevalence in H. halys from mid-Atlantic, North America in 2015-2016 ranged from 0.0% to 28.3%, while prevalence in C. hilaris collected in Illinois in 1970-1972 ranged from 14.3% to 58.8%. Oral infectivity and pathogenicity were confirmed in H. halys and C. hilaris. Morphological, ultrastructural, and ecological features of the microsporidium, together with a molecular phylogeny, establish a new species named Nosema maddoxi sp. nov.
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Affiliation(s)
- Ann E Hajek
- Department of Entomology, Cornell University, Ithaca, New York, 14853-2601, USA
| | - Leellen F Solter
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, Illinois, 61820, USA
| | - Joseph V Maddox
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, Illinois, 61820, USA
| | - Wei-Fone Huang
- College of Bee Science, Fujian Agriculture and Forestry University, Fujian, Fuzhou, 350002, China
| | - Alden S Estep
- Navy Entomology Center of Excellence, Naval Air Station, Jacksonville, Florida, 32212, USA.,Center for Medical, Agricultural and Veterinary Entomology - CMAVE (USDA, ARS), Gainesville, Florida, 32608, USA
| | - Grzegorz Krawczyk
- Department of Entomology, Fruit Research and Extension Center, Pennsylvania State University, Biglerville, Pennsylvania, 17307, USA
| | - Donald C Weber
- USDA ARS Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, Maryland, 20705, USA
| | - Kim A Hoelmer
- USDA ARS Beneficial Insect Introduction Research Unit, Newark, Delaware, 19713, USA
| | - Neil D Sanscrainte
- Center for Medical, Agricultural and Veterinary Entomology - CMAVE (USDA, ARS), Gainesville, Florida, 32608, USA
| | - James J Becnel
- Center for Medical, Agricultural and Veterinary Entomology - CMAVE (USDA, ARS), Gainesville, Florida, 32608, USA
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Ryan JA, Kohler SL. Distribution, prevalence, and pathology of a microsporidian infecting freshwater sculpins. DISEASES OF AQUATIC ORGANISMS 2016; 118:195-206. [PMID: 27025307 DOI: 10.3354/dao02974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Microsporidian infections are common in many fish species, yet detailed studies of these parasites in ecologically important wild populations are rare. Phylogenetic analysis using rDNA sequence data and parasite morphology indicate that mottled sculpin Cottus bairdii and slimy sculpin C. cognatus are hosts for Glugea sp. microsporidia in the northern USA. Glugea sp. is common in the Michigan populations sampled for this study, and prevalence was ≥ 70% in 4 of 6 infected populations (range -4 to 80%). Glugea sp. infection causes the formation of xenomas associated with the body wall, fat body, gonads, and kidneys. Infections range from mild to very heavy, with variable xenoma numbers and sizes. Female sculpin experience heavier infections and more frequent infection of the gonads relative to males. Glugea sp. is transmitted horizontally between hosts through ingestion of spores. Vertical transmission may also be possible, either by spores infecting eggs directly or by spores contaminating the surface of eggs in the ovary or in the nest. The frequency and route of vertical transmission requires further study, but if it occurs, it may partly explain the high prevalence of infection. Our study combined with previous research suggests that additional molecular data and cross-infection experiments should be conducted to clarify species designations in the genus Glugea.
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Affiliation(s)
- Julie A Ryan
- Department of Biological Sciences and Environmental and Sustainability Studies Program, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5410, USA
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Liu H, Li M, He X, Cai S, He X, Lu X. Transcriptome sequencing and characterization of ungerminated and germinated spores of Nosema bombycis. Acta Biochim Biophys Sin (Shanghai) 2016; 48:246-56. [PMID: 26837419 DOI: 10.1093/abbs/gmv140] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 11/21/2015] [Indexed: 12/23/2022] Open
Abstract
Nosema bombycis is an obligate intracellular parasitic fungus that utilizes a distinctive mechanism to infect Bombyx mori. Germination, an indispensible process through which microsporidia infect the host cells, is regarded as a key developmental turning point for microsporidia from dormant state to reproduction state. Thus, elucidating the transcriptome changes before and after germination is crucial for parasite control. However, the molecular basis of germination of microsporidia remains unknown. To investigate this germination process, the transcriptome of N. bombycis ungerminated spores and germinated spores were sequenced and analyzed. More than 60 million high-quality transcript reads were generated from these two groups using RNA-Seq technology. After assembly, 2756 and 2690 unigenes were identified, respectively, and subsequently annotated based on known proteins. After analysis of differentially expressed genes, 66 genes were identified to be differentially expressed (P ≤ 0.05) between these two groups. A protein phosphatase-associated gene was first identified to be significantly up-regulated as determined by RNA-Seq and immunoblot analysis, indicating that dephosphorylation might potentially contribute to microsporidia germination. The DEGs that encode proteins involved in glycometabolism, spore wall proteins and ricin B lectin of N. bombycis were also analyzed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed genes responsible for some specific biological functions and processes. The datasets generated in this study provide a basic characterization of the transcriptome changes in N. bombycis during germination. The analysis of transcriptome data and identification of certain functional genes which are robust candidate genes related to germination will help to provide a deep understanding of spore germination and invasion.
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Affiliation(s)
- Han Liu
- Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Mingqian Li
- Tongde Hospital of Zhejiang Province, Hangzhou 310058, China
| | - Xinyi He
- Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shunfeng Cai
- Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xiangkang He
- Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xingmeng Lu
- Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
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Weber AAT, Pawlowski J. Wide Occurrence of SSU rDNA Intragenomic Polymorphism in Foraminifera and its Implications for Molecular Species Identification. Protist 2014; 165:645-61. [DOI: 10.1016/j.protis.2014.07.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 07/09/2014] [Accepted: 07/16/2014] [Indexed: 11/28/2022]
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Sagastume S, Martín-Hernández R, Higes M, Henriques-Gil N. Ribosomal gene polymorphism in small genomes: analysis of different 16S rRNA sequences expressed in the honeybee parasite Nosema ceranae (Microsporidia). J Eukaryot Microbiol 2013; 61:42-50. [PMID: 24102764 DOI: 10.1111/jeu.12084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/14/2013] [Indexed: 01/10/2023]
Abstract
To date, few organisms have been shown to possess variable ribosomal RNA, otherwise considered a classic example of uniformity by concerted evolution. The polymorphism for the 16S rRNA in Nosema ceranae analysed here is striking as Microsporidia are intracellular parasites which have suffered a strong reduction in their genomes and cellular organization. Moreover, N. ceranae infects the honeybee Apis mellifera, and has been associated with the colony-loss phenomenon during the last decade. The variants of 16S rRNA include single nucleotide substitutions, one base insertion-deletion, plus a tetranucleotide indel. We show that different gene variants are expressed. The polymorphic sites tend to be located in particular regions of the rRNA molecule, and the comparison to the Escherichia coli 16S rRNA secondary structure indicates that most variations probably do not preclude ribosomal activity. The fact that the polymorphisms in such a minimal organism as N. ceranae are maintained in samples collected worldwide suggest that the existence of differently expressed rRNA may play an adaptive role in the microsporidian.
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Affiliation(s)
- Soledad Sagastume
- Centro Apícola Regional, Bee Pathology Laboratory, Marchamalo, Guadalajara, 19180, Spain
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