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International Journal of Molecular... Aug 2019Phylogenetic framework for the closely related Ancylodiscoidinae and Ancyrocephalinae subfamilies remains contentious. As this issue was never studied using a large...
Phylogenetic framework for the closely related Ancylodiscoidinae and Ancyrocephalinae subfamilies remains contentious. As this issue was never studied using a large molecular marker, we sequenced the first two Ancylodiscoidinae mitogenomes: and . Both mitogenomes had two non-coding regions (NCRs) that contained a number of repetitive hairpin-forming elements (RHE). Due to these, the mitogenome of (16,074 bp) is the longest among the Monogenea; especially large is its major NCR, with 3500 bp, approximately 1500 bp of which could not be sequenced (thus, the total mitogenome size is ≈ 17,600 bp). Although RHEs have been identified in other monopisthocotyleans, they appear to be independently derived in different taxa. The presence of RHEs may have contributed to the high gene order rearrangement rate observed in the two mitogenomes, including the first report of a transposition of rRNA genes within the Neodermata. Phylogenetic analyses using mitogenomic dataset produced Dactylogyrinae embedded within the Ancyrocephalinae (paraphyly), whereas Ancylodiscoidinae formed a sister-group with them. This was also supported by the gene order analysis. dataset produced polyphyletic Dactylogyridae and Ancyrocephalinae. The phylogeny of the two subfamilies shall have to be further evaluated with more data.
Topics: Animals; Evolution, Molecular; Gene Rearrangement; Genome, Helminth; Genome, Mitochondrial; Inverted Repeat Sequences; Phylogeny; Platyhelminths; RNA, Ribosomal
PubMed: 31466297
DOI: 10.3390/ijms20174214 -
Zoological Science Jun 2021In this paper, two new brackish-water species of the macrostomid turbellarian genus , sp. nov. and sp. nov., collected from coastal water at Shenzhen, Guangdong...
In this paper, two new brackish-water species of the macrostomid turbellarian genus , sp. nov. and sp. nov., collected from coastal water at Shenzhen, Guangdong Province, China, are described based on morphological, histological, and molecular phylogenetic analyses. sp. nov. differs from similar species within the genus in the length of the stylet (152 15.0 µm), diameter of stylet opening (20 4.0 µm proximally; 7 ± 0.5 µm distally), two bends of the stylet, and the non-spiral end of the stylet. sp. nov. differs from its congeners in the length of the stylet (81 7.4 µm), the stylet bending position and angle (50% and 60°), diameter of stylet proximal opening (15 ± 3.0 µm), sperm with bristles and brush, and the smooth-walled ovaries. Phylogenetic analyses inferred from nuclear 18S and 28S rRNA genes support the establishments of these two new species. In addition, reciprocal mating behavior of sp. nov. was observed and documented.
Topics: Animals; China; DNA, Helminth; Female; Male; Phylogeny; Platyhelminths; RNA, Ribosomal, 18S; RNA, Ribosomal, 28S; Species Specificity
PubMed: 34057353
DOI: 10.2108/zs200121 -
Journal of Biology 2010Acoel and platyhelminth worms are particularly attractive invertebrate models for stem-cell research because their bodies are continually renewed from large pools of... (Review)
Review
Acoel and platyhelminth worms are particularly attractive invertebrate models for stem-cell research because their bodies are continually renewed from large pools of somatic stem cells. Several recent studies, including one in BMC Developmental Biology, are beginning to reveal the cellular dynamics and molecular basis of stem-cell function in these animals.
Topics: Animals; Cell Proliferation; Gene Expression; Genes, Helminth; Helminth Proteins; Models, Animal; Platyhelminths; Stem Cell Research; Stem Cells
PubMed: 20236484
DOI: 10.1186/jbiol223 -
Zootaxa Oct 2018Polyclads are a conspicuous group of marine invertebrates, the most charismatic members of the phylum Platyhelminthes. From Brazil, a total of 71 polyclad species were...
Polyclads are a conspicuous group of marine invertebrates, the most charismatic members of the phylum Platyhelminthes. From Brazil, a total of 71 polyclad species were reported or described. Only three of them were recently described, five are recent records for the Brazilian coast, and 55 were described by Ernest and Eveline Marcus, who were by far the most productive workers. However, they quite often published in Portuguese or German, rather than English, and have not designated type material or specified material deposited in museum collections. Most of the polylcad material studied by the Marcus was found to be in the Swedish Museum of Natural History. Here we summarize the knowledge about Brazilian polyclad biodiversity, give information about deposited material in different museums for future reference, and designate type material for the species that did not have any. We examined 58 polyclad species reported from Brazil and designated type material and information available on type series of 52 species. Lectotypes (89 vouchers) were designated for 30 species and paralectotypes (73 specimens / 70 vouchers) were designated for 22 Brazilian species. Among the 261 type vouchers examined in this work, 22 species (77 vouchers) had material recognized as holotypes and 2 vouchers were recognized as paratypes. Of the total number of species reported from Brazil, 10 species remain without information about type material. In the present paper we also propose a new combination (Lurymare cynarium nov. comb.). Eleven species have their geographical distribution range broadened and 42 were photographed for the first time, five of those were photographed live as well. The number of Brazilian polyclad species is expected to rise when different regions and environments are surveyed.
Topics: Animals; Biodiversity; Brazil; Museums; Platyhelminths
PubMed: 30313726
DOI: 10.11646/zootaxa.4490.1.1 -
Journal of Helminthology May 2018Five species of Urocleidoides (one new) and two new species of Constrictoanchoratus n. gen. are described in this study. All were collected from the gills of Hoplias...
Dactylogyrids (Platyhelminthes, Monogenoidea) from the gills of Hoplias malabaricus (Characiformes: Erythrinidae) from coastal rivers of the Oriental Amazon Basin: species of Urocleidoides and Constrictoanchoratus n. gen.
Five species of Urocleidoides (one new) and two new species of Constrictoanchoratus n. gen. are described in this study. All were collected from the gills of Hoplias malabaricus (Characiformes: Erythrinidae) captured in six localities of coastal rivers of the north-eastern sector the State of Pará (Oriental Amazon): Urocleidoides brasiliensis Rosim, Mendoza-Franco & Luque, 2011; Urocleidoides bulbophallus n. sp.; Urocleidoides cuiabai Rosim, Mendoza-Franco & Luque, 2011; Urocleidoides eremitus Kritsky, Thatcher & Boeger, 1986; Urocleidoides malabaricusi Rosim, Mendoza-Franco & Luque, 2011; Constrictoanchoratus lemmyi n. gen. n. sp.; and Constrictoanchoratus ptilonophallus n. gen. n. sp. This is the first reported occurrence of the four previously described species of Urocleidoides parasitizing H. malabaricus from streams in the Oriental Amazon Basin. The analysis of voucher specimens of U. eremitus parasitizing the gills of H. malabaricus from the Upper Paraná River floodplain in the limits of States of Paraná and Mato Grosso do Sul, Brazil, indicates that these specimens are members of a new species of Urocleidoides, described here as Urocleidoides paranae n. sp. Constrictoanchoratus n. gen. is proposed for the species with a male copulatory organ sclerotized, coiled, clockwise; ventral anchor with elongate superficial root, inconspicuous deep root; dorsal anchor with inconspicuous roots, and a constriction at the intersection between the shaft and the point. The host-parasite diversity scenario and host specificity of the species of Constrictoanchoratus n. gen. and Urocleidoides from the gills of H. malabaricus are also discussed in this study.
Topics: Animals; Brazil; Characiformes; Fish Diseases; Gills; Host Specificity; Host-Parasite Interactions; Platyhelminths; Rivers
PubMed: 28502254
DOI: 10.1017/S0022149X17000384 -
Proceedings of the National Academy of... Mar 2019The flatworm features a duo-gland adhesive system that allows it to repeatedly attach to and release from substrates in seawater within a minute. However, little is...
The flatworm features a duo-gland adhesive system that allows it to repeatedly attach to and release from substrates in seawater within a minute. However, little is known about the molecules involved in this temporary adhesion. In this study, we show that the attachment of relies on the secretion of two large adhesive proteins, adhesion protein 1 (Mlig-ap1) and Mlig-ap2. We revealed that both proteins are expressed in the adhesive gland cells and that their distribution within the adhesive footprints was spatially restricted. RNA interference knockdown experiments demonstrated the essential function of these two proteins in flatworm adhesion. Negatively charged modified sugars in the surrounding water inhibited flatworm attachment, while positively charged molecules impeded detachment. In addition, we found that could not adhere to strongly hydrated surfaces. We propose an attachment-release model where Mlig-ap2 attaches to the substrate and Mlig-ap1 exhibits a cohesive function. A small negatively charged molecule is secreted that interferes with Mlig-ap1, inducing detachment. These findings are of relevance for fundamental adhesion science and efforts to mitigate biofouling. Further, this model of flatworm temporary adhesion may serve as the starting point for the development of synthetic reversible adhesion systems for medicinal and industrial applications.
Topics: Adhesives; Animals; Cell Adhesion; Female; Gene Knockdown Techniques; Gonads; Helminth Proteins; Intracellular Signaling Peptides and Proteins; Male; Platyhelminths; RNA Interference; Signal Transduction
PubMed: 30782790
DOI: 10.1073/pnas.1814230116 -
Journal of Helminthology Dec 2020The free-living infectious stages of macroparasites, specifically, the cercariae of trematodes (flatworms), are likely to be significant (albeit underappreciated)...
The free-living infectious stages of macroparasites, specifically, the cercariae of trematodes (flatworms), are likely to be significant (albeit underappreciated) vectors of nutritionally important polyunsaturated fatty acids (PUFA) to consumers within aquatic food webs, and other macroparasites could serve similar roles. In the context of de novo omega-3 (n-3) PUFA biosynthesis, it was thought that most animals lack the fatty acid (FA) desaturase enzymes that convert stearic acid (18:0) into ɑ-linolenic acid (ALA; 18:3n-3), the main FA precursor for n-3 long-chain PUFA. Recently, novel sequences of these enzymes were recovered from 80 species from six invertebrate phyla, with experimental confirmation of gene function in five phyla. Given this wide distribution, and the unusual attributes of flatworm genomes, we conducted an additional search for genes for de novo n-3 PUFA in the phylum Platyhelminthes. Searches with experimentally confirmed sequences from Rotifera recovered nine relevant FA desaturase sequences from eight species in four genera in the two exclusively endoparasite classes (Trematoda and Cestoda). These results could indicate adaptations of these particular parasite species, or may reflect the uneven taxonomic coverage of sequence databases. Although additional genomic data and, particularly, experimental study of gene functionality are important future validation steps, our results indicate endoparasitic platyhelminths may have enzymes for de novo n-3 PUFA biosynthesis, thereby contributing to global PUFA production, but also representing a potential target for clinical antihelmintic applications.
Topics: Animals; Fatty Acid Desaturases; Fatty Acids, Omega-3; Helminth Proteins; Platyhelminths; Prospective Studies
PubMed: 33298236
DOI: 10.1017/S0022149X20000954 -
Zootaxa Jul 2020The flatworms of the suborder Cotylea live in diverse marine substrates such as rocks, seaweed and sand or in association with corals. In the Mexican Pacific,...
The flatworms of the suborder Cotylea live in diverse marine substrates such as rocks, seaweed and sand or in association with corals. In the Mexican Pacific, particularly on the coast of Oaxaca, knowledge about cotyleans is scarce, with only one record of the genus Pseudoceros. The aim of this work was to describe the cotylean species present in the area. A total of 48 specimens were collected, fixed, mounted in whole mounts or histological sagittal and frontal histological sections of the reproductive systems. These were examined for taxonomic identification, determining five new species of four genera: Boninia oaxaquensis sp. nov., Pericelis sigmeri sp. nov., Pericelis nazahui sp. nov., Pseudoceros bicuti sp. nov. and Thysanozoon estacahuitensis sp. nov. The present study establishes the first record of the genus Boninia and the family Boniniidae for the Tropical Eastern Pacific. It also confirms the presence of the genus Pseudoceros on the coast of Oaxaca, and break the disjunct distribution of this genus (from Gulf of California to Gulf of Tehuantepec), as well as the genus Pericelis (from Canada to Galapagos Islands) and Thysanozoon (from Chile to Gulf of California).
Topics: Animal Distribution; Animals; Mexico; Platyhelminths
PubMed: 33055670
DOI: 10.11646/zootaxa.4819.1.3 -
Journal of Helminthology Feb 2023We describe two new species of monogenean parasites of the genus von Nordmann, 1832 infecting Neotropical catfishes (Siluriformes) in southern Mexico: n. sp. from...
We describe two new species of monogenean parasites of the genus von Nordmann, 1832 infecting Neotropical catfishes (Siluriformes) in southern Mexico: n. sp. from 'chulín', collected in Oaxaca; and n. sp. from 'juil', from Veracruz. Morphologically, both new taxa are similar to spp. infecting catfishes (Siluriformes) in South America. Sequences of the internal transcribed spacers (ITS1-5.8S-ITS2 rDNA), the D2+D3 domains of the large ribosomal subunit (28S rDNA) and the cytochrome oxidase II (COII) gene were obtained from multiple parasite specimens and analysed using Bayesian inference. Phylogenetic hypotheses using ITS rDNA and COII genes, recovered two new species from spp.: n. sp.; and n. sp., which are sister species to , a parasite of in Brazil, and show strong affinity to other gyrodactytlids infecting Neotropical catfishes. This suggests that these new taxa, the first gyrodactylids described from spp. in Mexico, co-migrated to Tropical Middle America with their Neotropical catfish hosts, after the emergence of the Isthmus of Panama.
Topics: Animals; Laticauda; Catfishes; Mexico; Phylogeny; Bayes Theorem; Fish Diseases; Species Specificity; Trematoda; Platyhelminths; DNA, Ribosomal; Brazil
PubMed: 36785879
DOI: 10.1017/S0022149X22000918 -
Molecular Biology and Evolution May 1997In most zoological textbooks, Platyhelminthes are depicted as an early-emerging clade forming the likely sister group of all the other Bilateria. Other phylogenetic... (Comparative Study)
Comparative Study
In most zoological textbooks, Platyhelminthes are depicted as an early-emerging clade forming the likely sister group of all the other Bilateria. Other phylogenetic proposals see them either as the sister group of most of the Protostomia or as a group derived from protostome coelomate ancestors by progenesis. The main difficulty in their correct phylogenetic placing is the lack of convincing synapomorphies for all Platyhelminthes, which may indicate that they are polyphyletic. Moreover, their internal phylogenetic relationships are still uncertain. To test these hypotheses, new complete 18S rDNA sequences from 13 species of "Turbellaria" have been obtained and compared to published sequences of 2 other "Turbellaria," 3 species of parasitic Platyhelminthes, and several diploblastic and deuterostome and protostome triploblastics. Maximum-parsimony, maximum-likelihood, and neighbor-joining methods were used to infer their phylogeny. The results show the order Catenulida to form an independent early-branching clade and emerge as a potential sister group of the rest of the Bilateria, while the rest of Platyhelminthes (Rhabditophora), which includes the parasites, form a clear monophyletic group closely related to the protostomes. The order Acoela, morphologically considered as candidates to be ancestral, are shown to be fast-clock organisms for the 18S rDNA gene. Hence, long-branching of acoels and insufficient sampling of catenulids and acoels leave their position still unresolved and call for further studies. Within the Rhabditophora, our analyses suggest (1) a close relationship between orders Macrostomida and Polycladida, forming a clear sister group to the rest of orders; (2) that parasitic platyhelminthes appeared early in the evolution of the group and form a sister group to a still-unresolved clade made by Nemertodermatida, Lecithoepitheliata, Prolecithophora, Proseriata, Tricladida, and Rhabdocoela; and (3) that Seriata is paraphyletic.
Topics: Animals; Base Sequence; DNA Primers; DNA, Helminth; DNA, Ribosomal; Evolution, Molecular; Molecular Sequence Data; Phylogeny; Platyhelminths; Polymerase Chain Reaction; RNA, Helminth; RNA, Ribosomal, 18S; Sequence Alignment; Species Specificity
PubMed: 9159926
DOI: 10.1093/oxfordjournals.molbev.a025785