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Orosová M, Marková A, Zrzavá M, Marec F, Oros M. Chromosome analysis and the occurrence of B chromosomes in fish parasite Acanthocephalus anguillae (Palaeacanthocephala: Echinorhynchida). Parasite 2023; 30:44. [PMID: 37870409 PMCID: PMC10592040 DOI: 10.1051/parasite/2023045] [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: 05/21/2023] [Accepted: 09/27/2023] [Indexed: 10/24/2023] Open
Abstract
The cytogenetics of Acanthocephala is a neglected area in the study of this group of endoparasites. Chromosome number and/or karyotypes are known for only 12 of the 1,270 described species, and molecular cytogenetic data are limited to rDNA mapping in two species. The standard karyological technique and mapping of 18S rRNA and H3 histone genes on the chromosomes of Acanthocephalus anguillae individuals from three populations, one of which originated from the unfavorable environmental conditions of the Zemplínska Šírava reservoir in eastern Slovakia, were applied for the first time. All specimens had 2n = 7/8 (male/female); n = 1m + 1m-sm + 1a + 1a (X). Fluorescence in situ hybridization (FISH) revealed three loci of 18S rDNA on two autosomes and dispersion of H3 histone genes on all autosomes and the X chromosome. In addition to the standard A chromosome set, 34% of specimens from Zemplínska Šírava possessed a small acrocentric B chromosome, which was always found to be univalent, with no pairing observed between the B chromosome and the A complement. The B chromosome had a small amount of heterochromatin in the centromeric and telomeric regions of the chromosomal arms and showed two clusters of H3 genes. It is well known that an environment permanently polluted with chemicals leads to an increased incidence of chromosomal rearrangements. As a possible scenario for the B chromosome origin, we propose chromosomal breaks due to the mutagenic effect of pollutants in the aquatic environment. The results are discussed in comparison with previous chromosome data from Echinorhynchida species.
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Affiliation(s)
- Martina Orosová
- Institute of Parasitology, Slovak Academy of Sciences Hlinkova 3 040 01 Košice Slovakia
| | - Anna Marková
- Institute of Parasitology, Slovak Academy of Sciences Hlinkova 3 040 01 Košice Slovakia
- Department of Zoology, Faculty of Natural Sciences, Comenius University Ilkovičova 6 842 15 Bratislava Slovakia
| | - Magda Zrzavá
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology Branišovská 31 370 05 České Budějovice Czech Republic
- Faculty of Science, University of South Bohemia Branišovská 1760 370 05 České Budějovice Czech Republic
| | - František Marec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology Branišovská 31 370 05 České Budějovice Czech Republic
| | - Mikuláš Oros
- Institute of Parasitology, Slovak Academy of Sciences Hlinkova 3 040 01 Košice Slovakia
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Orosová M, Marková A, Marec F, Barčák D, Brázová T, Oros M. New cytogenetic data on Caryophyllaeus laticeps and Paracaryophyllaeus gotoi, parasites of evolutionary interest. Parasitology 2022; 149:1094-1105. [PMID: 35535487 PMCID: PMC11010498 DOI: 10.1017/s0031182022000622] [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: 02/08/2022] [Revised: 04/20/2022] [Accepted: 04/29/2022] [Indexed: 11/07/2022]
Abstract
Caryophyllideans are intestinal parasites of freshwater fishes, occupying a basal position among the ‘true’ tapeworms. We performed detailed cytogenetic analyses of the well-known caryophyllidean species Caryophyllaeus laticeps. For comparison, we also examined for the first time the chromosomes of Paracaryophyllaeus gotoi, a specific parasite of loaches in China. Both species showed a diploid chromosome number of 2n = 20, n = 10m. Chromomycin A3 (CMA3)/diamidino-2-phenylindole (DAPI) staining performed for the first time in the class Cestoda revealed CMA3+/DAPI− bands in the pericentromeric regions of the short arms of chromosome pair no. 7 in the karyotype of C. laticeps. Fluorescence in situ hybridization with the 18S rDNA probe confirmed the presence of a single cluster of major rDNA near the centromere on a pair of small chromosomes in both species. These findings support the hypothesis that the ancestral state in the family Caryophyllaeidae is a single interstitial cluster of major rDNA genes and thus one nucleolar organizer region per haploid genome. Our results, which we presented together with literature data plotted on a phylogenetic tree, show stability of caryophyllidean karyotypes at the genus level, but showed differences between genera without a clear phylogenetic signal. The data allowed us to at least formulate a hypothesis about the ancestral haploid chromosome number of n = 10 for the family Caryophyllaeidae and possibly for the sister family Capingentidae. In addition, we compared two populations of C. laticeps from water bodies with different levels of polychlorinated biphenyl contamination, showing a slightly increased incidence of chromosomal abnormalities at the contaminated site.
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Affiliation(s)
- Martina Orosová
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovakia
| | - Anna Marková
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovakia
| | - František Marec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Daniel Barčák
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovakia
| | - Timea Brázová
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovakia
| | - Mikuláš Oros
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovakia
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Orosová M, Marková A, Provazníková I, Oros M, Radačovská A, Čadková Z, Marec F. Molecular cytogenetic analysis of a triploid population of the human broad tapeworm, Dibothriocephalus latus (Diphyllobothriidea). Parasitology 2021; 148:787-797. [PMID: 33678200 PMCID: PMC11010143 DOI: 10.1017/s0031182021000408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 11/06/2022]
Abstract
The large-sized tapeworm Dibothriocephalus latus is known as the broad or fish-borne cestode of mammals that is capable to infect humans and cause diphyllobothriosis. Recently, molecular data on D. latus has been accumulating in the literature and a complete genome sequence has been published; however, little is known about the karyotype and chromosome architecture. In this study, an in-depth karyological analysis of 2 D. latus specimens was carried out. The plerocercoids originated from a perch caught in subalpine Lake Iseo (Italy) and the tapeworms were reared in hamsters. Both specimens contained cells with a highly variable number of chromosomes ranging from18 to 27. Nevertheless, the largest portion of mitotic figures (47%) showed a number corresponding to the triploid set, 3n = 27. Accordingly, the karyotype of the analyzed specimens consisted of 9 triplets of metacentric chromosomes. Fluorescence in situ hybridization (FISH) with the 18S rDNA probe clearly demonstrated the presence of 3 clusters of hybridization signals on the triplet of chromosome 7, thus confirming the triploid status of the specimens. FISH with a telomeric (TTAGGG)n probe confined hybridization signals exclusively to the terminal chromosomal regions, supporting the earlier findings that this repetitive motif is a conserved feature of tapeworm telomeres.
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Affiliation(s)
- Martina Orosová
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, Košice04001, Slovakia
| | - Anna Marková
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, Košice04001, Slovakia
| | - Irena Provazníková
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, České Budějovice37005, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice37005
| | - Mikuláš Oros
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, Košice04001, Slovakia
| | - Alžbeta Radačovská
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, Košice04001, Slovakia
| | - Zuzana Čadková
- Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Science Prague (CZU), Kamýcká 129, Prague16500
| | - František Marec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, České Budějovice37005, Czech Republic
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Olson PD, Tracey A, Baillie A, James K, Doyle SR, Buddenborg SK, Rodgers FH, Holroyd N, Berriman M. Complete representation of a tapeworm genome reveals chromosomes capped by centromeres, necessitating a dual role in segregation and protection. BMC Biol 2020; 18:165. [PMID: 33167983 PMCID: PMC7653826 DOI: 10.1186/s12915-020-00899-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/14/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Chromosome-level assemblies are indispensable for accurate gene prediction, synteny assessment, and understanding higher-order genome architecture. Reference and draft genomes of key helminth species have been published, but little is yet known about the biology of their chromosomes. Here, we present the complete genome of the tapeworm Hymenolepis microstoma, providing a reference quality, end-to-end assembly that represents the first fully assembled genome of a spiralian/lophotrochozoan, revealing new insights into chromosome evolution. RESULTS Long-read sequencing and optical mapping data were added to previous short-read data enabling complete re-assembly into six chromosomes, consistent with karyology. Small genome size (169 Mb) and lack of haploid variation (1 SNP/3.2 Mb) contributed to exceptionally high contiguity with only 85 gaps remaining in regions of low complexity sequence. Resolution of repeat regions reveals novel gene expansions, micro-exon genes, and spliced leader trans-splicing, and illuminates the landscape of transposable elements, explaining observed length differences in sister chromatids. Syntenic comparison with other parasitic flatworms shows conserved ancestral linkage groups indicating that the H. microstoma karyotype evolved through fusion events. Strikingly, the assembly reveals that the chromosomes terminate in centromeric arrays, indicating that these motifs play a role not only in segregation, but also in protecting the linear integrity and full lengths of chromosomes. CONCLUSIONS Despite strong conservation of canonical telomeres, our results show that they can be substituted by more complex, species-specific sequences, as represented by centromeres. The assembly provides a robust platform for investigations that require complete genome representation.
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Affiliation(s)
- Peter D. Olson
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD UK
| | - Alan Tracey
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA UK
| | - Andrew Baillie
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD UK
| | - Katherine James
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD UK
- Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST UK
| | - Stephen R. Doyle
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA UK
| | - Sarah K. Buddenborg
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA UK
| | - Faye H. Rodgers
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA UK
| | - Nancy Holroyd
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA UK
| | - Matt Berriman
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA UK
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Chmúrčiaková N, Kašný M, Orosová M. Cytogenetics of Eudiplozoon nipponicum (Monogenea, Diplozoidae): Karyotype, spermatocyte division and 18S rDNA location. Parasitol Int 2019; 76:102031. [PMID: 31770588 DOI: 10.1016/j.parint.2019.102031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 10/25/2022]
Abstract
Ectoparasitic monogeneans of the family Diplozoidae have direct and monoxenous life cycle. The cytogenetics of monogeneans in general and diplozoids in particular, is a relatively underexplored area. This is why each new detailed description of a karyotype provides significant information about the evolution of monogenean chromosomes and contributes to a better understanding of phylogenetic relationships within this group. This study offers new data on the chromosomes of Eudiplozoon nipponicum, an invasive parasite of the common carp. This species' karyotype consists of seven pairs of telocentric chromosomes (2n = 14 t). After DAPI staining, we marked heterochromatin blocks on all chromosomes in the pericentromeric region. Silver staining (AgNO3) and staining with fluorescent dye YOYO-1 revealed the presence of one large active nucleolus. Fluorescent in situ hybridization with an 18S rDNA probe revealed one cluster of ribosomal genes at the terminal part of the long arms of chromosome pair No. 7. We compared our results with studies on the phylogenetic relationships of diplozoids which applied a combination of molecular methods and classical morphological characterization and found that the results of our cytogenetic analysis are consistent with the hypothesis that E. nipponicum is more basal member of the family Diplozoidae.
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Affiliation(s)
- Nikola Chmúrčiaková
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Martin Kašný
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Martina Orosová
- Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 040 01 Košice, Slovakia.
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Chromosomal study of Khawia abbottinae (Cestoda: Caryophyllidea): karyotype and localization of telomeric and ribosomal sequences after fluorescence in situ hybridization (FISH). Parasitol Res 2019; 118:2789-2800. [DOI: 10.1007/s00436-019-06450-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/28/2019] [Indexed: 01/27/2023]
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