Biomedical subjects

J Mariaux

Publications and source records attributed to J Mariaux.

10 recordsLinked to original sources

PubMed2000

Phylogenetic analysis of the suborder plagiorchiata (Platyhelminthes, Digenea) based on partial lsrDNA sequences.

The phylogenetic relationships and systematic position of the members of the suborder Plagiorchiata, one of the derived and most diverse groups of Digenea, have always been controversial. Here, we present a phylogeny of this group based on the analysis of partial sequences of the lsrDNA in 28 species representing 13 families of Plagiorchiata, as well as four outgroups. Our results show that the Plagiorchiata, as considered by most authors, is not monophyletic, and that the superfamilies Opecoeloidea, and most probably Dicrocoelioidea and Gorgoderoidea, may have to be removed from this suborder. According to our results, the Plagiorchiata includes only parasites of terrestrial vertebrates. We find the Plagiorchiata to be composed of two well-supported clades which can be ranked as superfamilies: (1) Plagiorchioidea, including the Plagiorchiidae, Haematoloechidae, Telorchiidae, Brachycoeliidae and Leptophallidae; and (2) Microphalloidea containing the Microphallidae, Prosthogonimidae, Lecithodendriidae and Pleurogenidae. The genetic analysis also allowed revision of the position of several taxa of Plagiorchiata, including: (1) a confirmation of the position of the Brachycoeliidae within the Plagiorchiata; (2) a close phylogenetic relationships of Macrodera with Paralepoderma, Leptophallus and Metaleptophallus; (3) the grouping of Opisthioglyphe and Telorchis within a distinct and strongly supported clade; and (4) the placement of Allassogonoporus amphoraeformis within the Pleurogenidae, and not close to Lecithodendriidae. Some systematic changes, corresponding to these results, are proposed.

Animals↗

PubMed2000

Nomimoscolex suspectus n. sp. (Eucestoda: Proteocephalidea: Zygobothriinae) with morphological and molecular phylogenetic analyses of the genus.

We describe a new species of Nomimoscolex from the Amazon siluriform fishes Brachyplatystoma filamentosum, B. flavicans and B. vaillanti. It differs from N. piraeeba in a lower mean number of testes, the paramuscular position of the vitelline follicles, the ovarian width/proglottis width ratio and the cirrus-pouch length/proglottis width ratio. Protein electrophoresis assays performed for 25 enzymatic systems showed that specimens of N. suspectus n. sp. from the three host species form a homogenous population which was genetically isolated from N. piraeeba and N. dorad. Moreover, the latter two species, synonymised by Rego (1991) because of their close morphological similarity, could be separated at eight loci. We thus restore N. dorad as a valid species. We finally examined the composition of the genus Nomimoscolex using DNA sequences from the 5.8S rRNA, ITS-2 and 28S rRNA nuclear ribosomal genes and a matrix of 24 morphological characters. Phylogenetic relationships were inferred for nine species of the genus, five members of other monticelliid genera and two outgroup species. The results of the phylogenetic analyses performed on morphological and molecular characters converged with those from allozyme studies and showed that N. suspectus, N. piraeeba and N. dorad clustered in a distinct clade that excluded other members of the genus. We therefore recognised them as an aggregate of species to reflect an isolation supported by both morphological and genetic data. Because relationships among the remaining Nomimoscolex representatives and other genera were generally poorly resolved, regardless of the database analysed, no action was taken to reorganise them into alternative groupings.

Animals↗

PubMed2000

Molecular systematics of Mesocestoides sPP (cestoda: mesocestoididae) from domestic dogs (Canis familiaris) and coyotes (Canis latrans).

The genus Mesocestoides Vaillant, 1863 includes tapeworms of uncertain phylogenetic affinities and with poorly defined life histories. We previously documented 11 cases of peritoneal cestodiasis in dogs (Canis familiaris L.) in western North America caused by metacestodes of Mesocestoides spp. In the current study, DNA sequences were obtained from metacestodes collected from these dogs (n = 10), as well as proglottids from dogs (n = 3) and coyotes (Canis latrans Say, 1823 [n = 2]), and tetrathyridia representing laboratory isolates of M. corti (n = 3), and these data were analyzed phylogenetically. Two nuclear genetic markers, 18S ribosomal DNA and the second internal-transcribed spacer (ITS 2), were sequenced. Phylogenetic analysis of the 18S rDNA data recovered a monophyletic group composed of all samples of Mesocestoides spp., distinct from closely related outgroup taxa (Amurotaenia Akhmerov, 1941 and Tetrabothrius Rudolphi, 1819). Initial analysis of the ITS 2 data resolved 3 clades within Mesocestoides. Two proglottids from dogs formed a basal clade, a second clade was represented by tetrathyridial isolates, and a third clade included all other samples. Interpretation of these data from an apomorphy-based perspective identified 6 evolutionary lineages. We also assessed whether metacestodes from dogs (n = 4) are capable of asexual proliferation in laboratory mice. One tetrathyridial and 2 acephalic isolates from dogs proliferated asexually. Further investigation is warranted to determine which of the lineages represent distinct species and to determine the life history strategies of Mesocestoides spp.

Animals↗

PubMed1999

Molecular systematic analysis of the order Proteocephalidea (Eucestoda) based on mitochondrial and nuclear rDNA sequences.

Two ribosomal DNA sequences were used to infer phylogenetic relationships among the Eucestoda order Proteocephalidea. A 437 bp portion of the 16S mitochondrial and a 1149 bp 5' portion of the nuclear large sub-unit rRNA molecule were sequenced for 53 proteocephalidean cestodes (representing nine subfamilies and 22 genera) and for one outgroup species. Parsimony and distance-based analyses of the two databases, alone and combined, failed to support the monophyly of the two traditionally accepted families, of numerous subfamilies (with the exception of the Rudolphielliinae and Othinoscolescinae which were validated in our analysis) and of various genera, including the genus Nomimoscolex (Woodland), Ophiotaenia (La Rue) as well as the type genus Proteocephalus (Weinland). Palaearctic Proteocephalus species nevertheless constituted a well-defined clade. The two genes globally yielded compatible results; however, the nuclear ribosomal gene provided a better resolution of relations among Proteocephalidea.

Animals↗

PubMed1998

A molecular phylogeny of the Eucestoda.

Evolutionary relationships among the orders of the Eucestoda were examined based on data derived from partial sequences of genes encoding 18S rRNA. Considered in this study were 47 species-level taxa, including 1 from Monogenea, 1 from Amphilinidea, both of which were used as outgroups, and 45 from 10 orders of Eucestoda. Parsimony analysis of 1.1 kbp of aligned fragments yielded 480 shortest trees (length 704; consistency index 0.41) the strict consensus of which shows the following relationships: (Monogenea, (Amphilinidea, (Caryophyllidea, (Spathebothriidea, (Trypanorhyncha, (Pseudophyllidea, (Tetraphyllidea, ((Diphyllidea, Proteocephalidea), ((Cyclophyllidea, Tetrabothriidea), Nippotaeniidea))))))))). The Tetraphyllidea, Pseudophyllidea (because of the Diphyllobothriidae), and Cyclophyllidea (because of the Mesocestoididae) were found to be paraphyletic. This tree is almost completely congruent with the most recent hypotheses based on characters derived from comparative morphology, ontogeny, and ultrastructural studies. The only discrepancies between these separate analyses were in the position of the Trypanorhyncha and Diphyllidea. Among the main conclusions corroborated here are the following: (1) the basal position of the Caryophyllidea (and Spathebothriidea), and hence the plesiomorphic condition of monozoism; (2) the monophyly of the "higher tetrafossates" provided the nippotaeniids and tetrabothriids are included; (3) the close relationship between the Tetrabothriidea and Cyclophyllidea; and (4) the paraphyly of the Tetraphyllidea. At lower taxonomic levels, structure could not be defined within Proteocephalidea; within the Cyclophyllidea, all families represented by several taxa (Hymenolepididae, Davaineidae, and Dilepididae) were found to be monophyletic, and Taeniidae may be the most basal family. Furthermore, the validity of the Gryporhynchidae is confirmed. and it is suggested that the Mesocestoididae should be excluded from the Cyclophyllidea.

Animals↗

PubMed1997

Phylogeny of the orders of the Eucestoda (Cercomeromorphae) based on comparative morphology: historical perspectives and a new working hypothesis.

The phylogeny of the Eucestoda was evaluated based on a suite of 49 binary and multistate characters derived from comparative morphological and ontogenetic studies; attributes of adult and larval tapeworms were considered. A single most parsimonious tree (MPT) (consistency index = 0.872; retention index = 0.838; and homoplasy index = 0.527) was fully resolved and is specified by the following: (Gyrocotylidea, (Amphilinidea, ((Spathebothriidea, (Pseudophyllidea, ((Diphyllidea, (Trypanorhyncha, (Tetraphyllidea, (Lecanicephalidea, ((Nippotaeniidea, (Tetrabothriidea, Cyclophyllidea)), Proteocephalidea))))), Haplobothriidea))), Caryophyllidea))). Monophyly for the Eucestoda was firmly corroborated. Trees derived from the primary and bootstrap analyses were congruent, but low values, particularly for relationships among the tetrafossate tapeworms, indicated additional examination is warranted. The MPT was found to be the most efficient hypothesis for describing character evolution and in specifying relationships among the orders when compared to those concepts that had been developed for the tapeworms over the past century. Areas of congruence were shared among the current hypothesis and one or more of the prior hypotheses. Major conclusions include: (1) Caryophyllidea are basal and monozooy is ancestral; (2) difossate forms are primitive, and the Pseudophyllidea are the sister group of the strongly polyzoic tapeworms; (3) Nippotaeniidea are highly derived; (4) the higher tapeworms (Tetraphyllidea, Lecanicephalidea, Proteocephalidea, Nippotaeniidea, Tetrabothriidea, and Cyclophyllidea) are closely related or potentially coordinate groups: (5) Tetrabothriidea and the Cyclophyllidea are sister groups; and (6) Tetraphyllidea is paraphyletic, with the Onchobothriidae basal to the Phyllobothriidae. Character support for placement of the Tetrabothriidea continues to be contradictory, and this order may represent a key to understanding the phylogeny of the higher cestodes. The current study constitutes a complete historical review and poses a new and robust hypothesis for the phylogeny of the Eucestoda.

Animals↗

PubMed1996

A molecular phylogenetic survey of the nightjars and allies (Caprimulgiformes) with special emphasis on the potoos (Nyctibiidae).

A 656-pb fragment of the mitochondrial cytochrome b gene was sequenced for six species of Central and South American potoos (genus Nyctibius, Nyctibiidae) as well as for selected representatives of all other caprimulgiform families. Sequence divergence among potoos was much higher (11.1-16.2%) than has typically been observed among congeneric species of birds, suggesting that the species of Nyctibius are quite old. Divergence among families was also quite high (13.7-21.8%), confirming recent DNA-DNA hybridization studies. Such high genetic divergences in a functionally constrained gene like cyt b indicate that many of those sites which are free to vary will have experienced multiple substitutions. We therefore performed phylogenetic analysis using parsimony under a variety of weighting schemes intended to reduce the effect of multiple substitutions. The monophyly of all the traditional caprimulgiform families was confirmed and a number of new hypotheses of relationship emerged. From our analysis, it appears that the oilbird (Steatornis) is an ancient member of the order, and it is not closely related to the potoos. We also note the close link between Aegothelidae and Caprimulgidae, and the basal position of the Podargidae/Batrachostomidae clade in the phylogeny. These results are in accordance with several classical works of the first half of the century. The relationships of the various Nyctibius species to each other have not been fully resolved; however, a close link between N. leucopterus and N. maculosus appears to be highly probable from our data.

Amino Acid Sequence↗

PubMed1996

Cestode systematics: any progress?

In this short review, I summarize the recent advances, the present state and future for research in the field of cestode systematics. First, within an historical context, I briefly outline why our understanding of relationships within the Eucestoda has been problematic and contentious. On this foundation, I then summarize and discuss recent progress at various supraspecific levels, and at the specific level. Of particular interest in this respect is the discrepancy between the methods applied to understand the evolution of a few well-studied taxa, for instance the complex of Echinococcus species, contrasted with our relative ignorance about the systematic status of the vast majority of species. This leads to a review of the diversity of classical and new methodologies currently applied in the field of cestode systematics. Applications of morphoanatomical investigations as well as more recent molecular tools are examined, and some less common approaches are also reviewed. Finally, several practical and theoretical difficulties that are specific to the domain are discussed. These include problems in accessibility of material and adequate consideration of host-specificity. Our current state of knowledge represents an apparent paradox in that significant progress has indeed been achieved during the last 15 years, but appears limited to very specific cases, principally among medically important taxa. Conversely, more general works whose utility has been long recognized have not been addressed despite their conceptual simplicity. Consequently the development of new techniques, especially molecular ones, to allow access to new classes of characters is encouraged. However the need for continuous effort using more traditional approaches, including continued field collection, excellent and detailed descriptions and redescriptions, as well as critical revisions of classical monographs is also emphasized. A synergism linking morphological and molecular characters and phylogenetic approaches to analysis provides a firm foundation for rapid and seminal advances in the elucidation of relationships among the Eucestoda.

Animals↗

PubMed1992

A new genus of Metadilepididae (Cestoda: Cyclophyllidea) parasitic in Terpsiphone rufiventer (Aves: Muscicapidae) from the Ivory Coast.

Pseudadelphoscolex eburnensis, a new genus and species of metadilepidid Cyclophyllidea parasitic in the red-bellied paradise flycatcher, Terpsiphone rufiventer, from the Ivory Coast, is described. The new species is characterized by davaineidlike rostellar hooks, absence of a rostellar pouch, a huge cirrus pouch in gravid proglottids, a bilobed uterus that becomes progressively reticular, absence of a paruterine organ, and eggs with an internal coat forming a crescentic protuberance outside the embryophore. The presence of a single row of rostellar hooks together with the lack of spines on the sucker and the structure and position of the uterus exclude this new material from Davaineidae. It cannot be placed in Dilepididae due to the lack of a rostellar pouch or in Paruterinidae because of the lack of a paruterine organ. The position of the excretory ducts in relation to the genital pores and the alternance of these pores are the main characters used to exclude this new species from the known genera of Metadilepididae. The diversity of forms of Metadilepididae in intertropical terrestrial birds is increased, and the validity of this taxon is strengthened.

Animals↗

PubMed1990

A new genus of Dilepididae (Cestoda) of the yellowbill Ceuthmochares aereus (Cuculidae) from the Ivory Coast.

Bonaia africana n. gen., n. sp. (Cestoda: Dilepididae) has been found in Ceuthmochares aereus (Aves: Cuculidae) in the Ivory Coast (West Africa). This new tapeworm is mainly characterized by its unusual rostellar hooks that are implanted irregularly and which present a variable form and length in the same rostellum. The differential diagnosis, particularly in comparison with the closely related genera Liga and Amoebotaenia, is presented: Liga possesses an atrial bundle of setae and Amoebotaenia 1 row of well built hooks with a typical blade. It is assumed that the unusual disposition of the rostellar hooks described here could be a transitional form between the 1- and 2-row patterns or a degenerate derivative of a regular arrangement.

Animals↗