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- Hallett, S. L., et al.
(författare)
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Molecular methods clarify morphometric variation in triactinomyxon spores (Myxozoa) released from different oligochaete hosts.
- 2004
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Ingår i: Systematic Parasitology. - 0165-5752. ; 57:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine freshwater tubificid oligochaetes were isolated, each of which harboured a triactinomyxon infection. Spore characteristics include the typical triactinomyxon anchor shape, eight germ cells within the sporoplasm and three unequal (two long and one shorter) caudal processes with square tips. Despite morphological similarities between the spores from the different hosts, their morphometrical data varied considerably; significantly, the ranges of dimensions of the smallest and largest exemplars were mutually exclusive. In order to ascertain the true number of spore types present, molecular methods were employed. Samples of waterborne spores, including the smallest and largest representatives, were selected from 11 host oligochaetes (all Tubifex tubifex Müller) and a nested PCR-RFLP `riboprint' analysis performed. The small subunit ribosomal DNA gene (18S rDNA) was targetted and amplified through two rounds of PCR, then digested with the restriction enzymes Dde I and Hha I. The resultant major cleavage patterns produced by both enzymes indicated a single triactinomyxon form; however, the pattern of several less intense bands varied between the samples. From a subset of five samples drawn from across the full spectrum of spore sizes, a 327 bp region near the 5prime was sequenced and was identical for all five samples. Comparison of this 327 bp region with that of 12 other triactinomyxons in GenBank showed 68.7–96.9% similarity (at least 9 base differences). A further 469 bp generated for each of the smallest, largest and mid-range (= reference) spore samples was identical also. The reference sample was sequenced further to yield 1,554 bp of 18S rDNA (GenBank accession number AY162270); comparison with other Myxozoa indicated this sequence was novel. The morphometrics of our triactinomyxon did not correlate with any published description. The morphometrical variation exhibited by spores of the triactinomyxon type in this study raises questions about the validity of using morphometrical data to distinguish spore types and suggests that there could be taxonomic redundancy in the diversity of actinosporeans recorded in the literature. The additional information provided by molecular data in this study was pivotal in the clarification of morphometrical variation exhibited by morphologically similar triactinomyxon spores released from different oligochaete hosts.
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| 4. |
- Westerman, Rickard, et al.
(författare)
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Aborjinia corallicola sp. n., a new nematode species (Nematoda: Marimermithidae) associated with the bamboo coral Acanella arbuscula (Johnson)
- 2021
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Ingår i: Systematic Parasitology. - : Springer Science and Business Media LLC. - 0165-5752 .- 1573-5192. ; 98, s. 559-579
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Tidskriftsartikel (refereegranskat)abstract
- A new species of Aborjinia Özdikmen, 2010 is described from the tissues of the cold-water bamboo coral Acanella arbuscula (Johnson) from the northwest Atlantic. Aborjinia corallicolasp. n. is characterized by 18.4–33.2 mm long body in adults; outer labial and cephalic sensilla papilliform and located 14–21 µm from anterior end, amphideal aperture located 22–41 µm from anterior end, excretory pore indistinct, rectum and anal opening functional, convex-conoid tail with broadly rounded terminus, spinneret subventral. It is placed in the genus Aborjinia based on the combination of the following characters: outer labial and cephalic sensilla papilliform in shape and located in one circle, contrary to Marimermis Rutsov & Platonova, 1974 (outer labial and cephalic sensilla setiform) and Ananus Rubtsov, 1977 and Thalassonema Ward, 1933 (outer labial and cephalic sensilla in separate circles, if known). From Aborjinia eulagiscae Tchesunov & Spiridonov, 1985 the new species differs in much shorter body, much shorter tail, presence of caudal glands and spinneret in adults, different host species. Our finding represents the first report of a nematode in a parasitic relationship with a cold-water octocoral. Phylogenetic relationships between Aborjinia and other nematodes are analyzed based on 18S rDNA sequences. Summary of all presently known species and genera of the family Marimermithidae is also given.
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| 5. |
- Westerman, Rickard, et al.
(författare)
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Gammarinema scyllae sp. n. and Monhystrium mangrovi sp. n. (Nematoda: Monhysteridae) from land crabs from New Caledonia
- 2022
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Ingår i: Systematic Parasitology. - : Springer Science and Business Media LLC. - 0165-5752 .- 1573-5192. ; 99:1, s. 83-101
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Tidskriftsartikel (refereegranskat)abstract
- Two new species of nematodes associated with crabs are described from New Caledonia. Gam-marinema scyllae sp. n. from the gill chambers of Scylla serrata (Forsskal) is characterised by 3–4 mmlong body, small outer labial and cephalic sensilla, distinct ocelli, short straight spicules and sub-cylin-drical tail. Monhystrium mangrovi sp. n. from the gill chambers and body cavity of mangrove crab Neosar-matium sp. is characterised by 1–1.4 mm long body; outer labial sensilla longer than cephalic sensilla,amphid located at level with posterior stoma chamber,denticles in posterior stoma chamber and five pairs ofgenital papilla on tail. Phylogenetic relationships oftwo new species and other nematodes from the familyMonhysteridae are analysed based on 18S and partial28S rDNA sequences.
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