The Experts below are selected from a list of 1065 Experts worldwide ranked by ideXlab platform
Donato Traversa - One of the best experts on this subject based on the ideXlab platform.
-
new insights into the morphology molecular characterization and identification of baylisascaris transfuga ascaridida Ascarididae
Veterinary Parasitology, 2011Co-Authors: Gabriella Testini, Donato Traversa, Filipe Dantastorres, Antonio Parisi, Roberto Amerigo Papini, Domenico OtrantoAbstract:Species ranked within the genus Baylisascaris (Ascaridida, Ascarididae) have been implicated in clinical and subclinical intestinal diseases in their natural hosts (e.g., raccoons and bears) as well as in life-threatening larva migrans syndromes in a number of incidental hosts, including humans. Following the diagnosis of Baylisascaris transfuga infestation in two captive polar bears, living in the zoo park of Pistoia (Tuscany, Italy), nematodes (n = 300; both sexes) have been characterized by morphological and molecular methods by sequencing and analysing ribosomal (large ribosomal DNA (28S) and internal transcribed spacer region 1 and 2 (ITSs)) and mitochondrial (cytochrome c oxidase subunit 1 (cox1) and cytochrome c oxidase subunit 2 (cox2)) target regions. In addition, seven faecal samples were collected from the animal enclosure and submitted to copromicroscopic and molecular examination. All nematodes were morphologically identified as B. transfuga and their main distinctive features are here presented. No variation in size and nucleotide polymorphisms was detected within each target sequence among all samples analysed. These data contribute to facilitate an accurate diagnosis of this little known nematode infestation in order to apply appropriate anthelmintic strategies.
-
Epidemiology and biology of nematodofauna affecting Testudo hermanni, Testudo graeca and Testudo marginata in Italy
Parasitology Research, 2005Co-Authors: Donato Traversa, Gioia Capelli, Raffaella Iorio, Salah Bouamer, Angelo Cameli, Annunziata GiangasperoAbstract:Tortoises of the genus Testudo living in Italy are Testudo hermanni , Testudo graeca and Testudo marginata . Although a great deal of information has been acquired on the internal medicine and surgery on these animals, little is known of their parasitological fauna. A survey on the presence of gastro-intestinal parasitic nematodes in tortoises bred in Italy was carried out to acquire extensive epidemiological data. Stool samples of 62 tortoises (37 T. hermanni hermanni , 13 T. graeca , 6 T. hermanni boettgeri and 6 T. marginata ) were macroscopically examined and subjected to qualitative (flotation and Baermann techniques) and quantitative (McMaster technique) microscopic examinations. Adult nematodes were identified using morphological keys. Eggs of oxyurids (species indistinguishable) and adults of Alaeuris numidica , Mehdiella microstoma , Mehdiella uncinata , Tachygonetria longicollis , Tachygonetria conica and Tachygonetria palearcticus (Oxyurida, Pharyngodonidae); larvae and adults of Atractis dactyluris (Ascaridida, Atractidae); and eggs and adults of Angusticaecum holopterum (Ascaridida, Ascarididae) were identified in all animals >1 year, whereas all tortoises
Luping Zhang - One of the best experts on this subject based on the ideXlab platform.
-
Morphological and molecular characterization of Seuratascaris numidica (Seurat, 1917) (Ascaridida: Ascarididae)
Acta Parasitologica, 2018Co-Authors: Huixia Chen, Kuang Zhang, Luping ZhangAbstract:Seuratascaris numidica (Seurat, 1917) is a specialized nematode species parasitizing amphibians only. In the present study, the detailed morphology of this poorly known species was studied using light and scanning electron microscopy based on the newly material collected from Hoplobatrachus chinensis (Osbeck) (Amphibia: Anura) in China. We found that the relative length of intestinal caecum in our male specimens (representing 68.4-71.1% of oesophageal length) is slighter longer than the previously reported data (not over 60.0% of oesophageal length). Our SEM observations also revealed the presence of ca. 64-76 small conical denticles on each lip. In addition, Angusticaecum wuyiensis Wang, 1981, collected from Rana schmackeri Boettger (Amphibia: Anura) from Wuyi Mountain in Fujian Province, China was considered as a new synonym of S. numidica. The ITS and cox1 sequences of S. numidica were also sequenced for the first time and there is no nucleotide variability detected in both regions. The present supplementary morphological and molecular data (especially the ITS and cox1 sequences) obtained herein is extremely important and useful to determine the morphological variability, population genetics and phylogenetic position of S. numidica in the future.
-
Molecular Phylogeny and Dating Reveal a Terrestrial Origin in the Early Carboniferous for Ascaridoid Nematodes
Systematic Biology, 2018Co-Authors: Steven A. Nadler, Huixia Chen, Luping Zhang, Wenting Zhao, David I. Gibson, Yan-ning GuoAbstract:Ascaridoids are among the commonest groups of zooparasitic nematodes (roundworms) and occur in the alimentary canal of all major vertebrate groups, including humans. They have an extremely high diversity and are of major socio-economic importance. However, their evolutionary history remains poorly known. Herein, we performed a comprehensive phylogenetic analysis of the Ascaridoidea. Our results divided the Ascaridoidea into six monophyletic major clades, i.e., the Heterocheilidae, Acanthocheilidae, Anisakidae, Ascarididae, Toxocaridae, and RaphidAscarididae, among which the Heterocheilidae, rather than the Acanthocheilidae, represents the sister clade to the remaining ascaridoids. The phylogeny was calibrated using an approach that involves time priors from fossils of the co-evolving hosts, and dates the common ancestor of the Ascaridoidea back to the Early Carboniferous (approximately 360.47-325.27 Ma). The divergence dates and ancestral host types indicated by our study suggest that members of the Ascaridoidea first parasitized terrestrial tetrapods, and subsequently, extended their host range to elasmobranchs and teleosts. We also propose that the fundamental terrestrial-aquatic switches of these nematodes were affected by changes in sea-level during the Triassic to the Early Cretaceous.
-
morphological study of ophidascaris excavata hsu hoeppli 1931 ascaridida Ascarididae from gloydius brevicaudus stejneger reptilia viperidae
Systematic Parasitology, 2016Co-Authors: Liang Li, Huixia Chen, Wenting Zhao, Luping ZhangAbstract:Ophidascaris excavata Hsu & Hoeppli, 1931 is a poorly known ascaridid parasite reported from the short-tailed pit viper Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae) in China. In the present paper, the detailed morphology of this nematode was studied using light and scanning electron microscopy (SEM) based on newly collected material. The results revealed several important, but previously unreported, morphological features, including the presence of one pair of small, finger-like prolongations on each lip, narrow cervical alae beginning well posterior to the base of the ventrolateral lips and the second pair of postcloacal ventro-lateral papillae being double; in addition, there is no intestinal caecum. These supplementary morphological and morphometric data, especially the detailed morphological features obtained herein under SEM, would help us to understand the relationships of O. excavata with its congeners and enable us to diagnose this species more accurately.
-
Morphological study of Ophidascaris excavata Hsü & Hoeppli, 1931 (Ascaridida: Ascarididae) from Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae)
Systematic Parasitology, 2016Co-Authors: Liang Li, Huixia Chen, Wenting Zhao, Luping ZhangAbstract:Ophidascaris excavata Hsu & Hoeppli, 1931 is a poorly known ascaridid parasite reported from the short-tailed pit viper Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae) in China. In the present paper, the detailed morphology of this nematode was studied using light and scanning electron microscopy (SEM) based on newly collected material. The results revealed several important, but previously unreported, morphological features, including the presence of one pair of small, finger-like prolongations on each lip, narrow cervical alae beginning well posterior to the base of the ventrolateral lips and the second pair of postcloacal ventro-lateral papillae being double; in addition, there is no intestinal caecum. These supplementary morphological and morphometric data, especially the detailed morphological features obtained herein under SEM, would help us to understand the relationships of O. excavata with its congeners and enable us to diagnose this species more accurately.
-
Further studies on Toxascaris leonina (Linstow, 1902) (Ascaridida: Ascarididae) from Felis lynx (Linnaeus) and Panthera leo (Linnaeus) (Carnivora: Felidae).
Acta Parasitologica, 2014Co-Authors: Li-mei Xue, Jing-bo Chai, Yan-ning Guo, Luping ZhangAbstract:Toxascaris leonina (Linstow, 1902) is a most common intestinal parasite of various animals in Felidae and Canidae. In the present paper, light and scanning electron microscopy (SEM) were used to study the morphological aspects of adult worms of this nematode in detail, based on the material collected from Panthera leo (Linnaeus) and Felis lynx (Linnaeus) (Carnivora: Felidae) in China. The results showed that there were some morphometric differences between the present material and the previous studies, including the body size, the width and length of cervical alae, the number of denticles on each lip and the tail length of the female. Previously unreported morphological features were also revealed. These supplementary morphological and morphometric data contributed to a more accurate identification of this worldwide distributed ascarid nematode.
Domenico Otranto - One of the best experts on this subject based on the ideXlab platform.
-
new insights into the morphology molecular characterization and identification of baylisascaris transfuga ascaridida Ascarididae
Veterinary Parasitology, 2011Co-Authors: Gabriella Testini, Donato Traversa, Filipe Dantastorres, Antonio Parisi, Roberto Amerigo Papini, Domenico OtrantoAbstract:Species ranked within the genus Baylisascaris (Ascaridida, Ascarididae) have been implicated in clinical and subclinical intestinal diseases in their natural hosts (e.g., raccoons and bears) as well as in life-threatening larva migrans syndromes in a number of incidental hosts, including humans. Following the diagnosis of Baylisascaris transfuga infestation in two captive polar bears, living in the zoo park of Pistoia (Tuscany, Italy), nematodes (n = 300; both sexes) have been characterized by morphological and molecular methods by sequencing and analysing ribosomal (large ribosomal DNA (28S) and internal transcribed spacer region 1 and 2 (ITSs)) and mitochondrial (cytochrome c oxidase subunit 1 (cox1) and cytochrome c oxidase subunit 2 (cox2)) target regions. In addition, seven faecal samples were collected from the animal enclosure and submitted to copromicroscopic and molecular examination. All nematodes were morphologically identified as B. transfuga and their main distinctive features are here presented. No variation in size and nucleotide polymorphisms was detected within each target sequence among all samples analysed. These data contribute to facilitate an accurate diagnosis of this little known nematode infestation in order to apply appropriate anthelmintic strategies.
Steven A. Nadler - One of the best experts on this subject based on the ideXlab platform.
-
Molecular Phylogeny and Dating Reveal a Terrestrial Origin in the Early Carboniferous for Ascaridoid Nematodes
Systematic Biology, 2018Co-Authors: Steven A. Nadler, Huixia Chen, Luping Zhang, Wenting Zhao, David I. Gibson, Yan-ning GuoAbstract:Ascaridoids are among the commonest groups of zooparasitic nematodes (roundworms) and occur in the alimentary canal of all major vertebrate groups, including humans. They have an extremely high diversity and are of major socio-economic importance. However, their evolutionary history remains poorly known. Herein, we performed a comprehensive phylogenetic analysis of the Ascaridoidea. Our results divided the Ascaridoidea into six monophyletic major clades, i.e., the Heterocheilidae, Acanthocheilidae, Anisakidae, Ascarididae, Toxocaridae, and RaphidAscarididae, among which the Heterocheilidae, rather than the Acanthocheilidae, represents the sister clade to the remaining ascaridoids. The phylogeny was calibrated using an approach that involves time priors from fossils of the co-evolving hosts, and dates the common ancestor of the Ascaridoidea back to the Early Carboniferous (approximately 360.47-325.27 Ma). The divergence dates and ancestral host types indicated by our study suggest that members of the Ascaridoidea first parasitized terrestrial tetrapods, and subsequently, extended their host range to elasmobranchs and teleosts. We also propose that the fundamental terrestrial-aquatic switches of these nematodes were affected by changes in sea-level during the Triassic to the Early Cretaceous.
-
Monophyly of clade III nematodes is not supported by phylogenetic analysis of complete mitochondrial genome sequences
BMC Genomics, 2011Co-Authors: Joongki Park, Tahera Sultana, Seokha Kang, Steven A. NadlerAbstract:Background The orders Ascaridida, Oxyurida, and Spirurida represent major components of zooparasitic nematode diversity, including many species of veterinary and medical importance. Phylum-wide nematode phylogenetic hypotheses have mainly been based on nuclear rDNA sequences, but more recently complete mitochondrial (mtDNA) gene sequences have provided another source of molecular information to evaluate relationships. Although there is much agreement between nuclear rDNA and mtDNA phylogenies, relationships among certain major clades are different. In this study we report that mtDNA sequences do not support the monophyly of Ascaridida, Oxyurida and Spirurida (clade III) in contrast to results for nuclear rDNA. Results from mtDNA genomes show promise as an additional independently evolving genome for developing phylogenetic hypotheses for nematodes, although substantially increased taxon sampling is needed for enhanced comparative value with nuclear rDNA. Ultimately, topological incongruence (and congruence) between nuclear rDNA and mtDNA phylogenetic hypotheses will need to be tested relative to additional independent loci that provide appropriate levels of resolution. Results For this comparative phylogenetic study, we determined the complete mitochondrial genome sequences of three nematode species, Cucullanus robustus (13,972 bp) representing Ascaridida, Wellcomia siamensis (14,128 bp) representing Oxyurida, and Heliconema longissimum (13,610 bp) representing Spirurida. These new sequences were used along with 33 published nematode mitochondrial genomes to investigate phylogenetic relationships among chromadorean orders. Phylogenetic analyses of both nucleotide and amino acid sequence datasets support the hypothesis that Ascaridida is nested within Rhabditida. The position of Oxyurida within Chromadorea varies among analyses; in most analyses this order is sister to the Ascaridida plus Rhabditida clade, with representative Spirurida forming a distinct clade, however, in one case Oxyurida is sister to Spirurida. Ascaridida, Oxyurida, and Spirurida (the sampled clade III taxa) do not form a monophyletic group based on complete mitochondrial DNA sequences. Tree topology tests revealed that constraining clade III taxa to be monophyletic, given the mtDNA datasets analyzed, was a significantly worse result. Conclusion The phylogenetic hypotheses from comparative analysis of the complete mitochondrial genome data (analysis of nucleotide and amino acid datasets, and nucleotide data excluding 3^rd positions) indicates that nematodes representing Ascaridida, Oxyurida and Spirurida do not share an exclusive most recent common ancestor, in contrast to published results based on nuclear ribosomal DNA. Overall, mtDNA genome data provides reliable support for nematode relationships that often corroborates findings based on nuclear rDNA. It is anticipated that additional taxonomic sampling will provide a wealth of information on mitochondrial genome evolution and sequence data for developing phylogenetic hypotheses for the phylum Nematoda.
-
monophyly of clade iii nematodes is not supported by phylogenetic analysis of complete mitochondrial genome sequences
BMC Genomics, 2011Co-Authors: Joongki Park, Tahera Sultana, Seokha Kang, Steven A. NadlerAbstract:The orders Ascaridida, Oxyurida, and Spirurida represent major components of zooparasitic nematode diversity, including many species of veterinary and medical importance. Phylum-wide nematode phylogenetic hypotheses have mainly been based on nuclear rDNA sequences, but more recently complete mitochondrial (mtDNA) gene sequences have provided another source of molecular information to evaluate relationships. Although there is much agreement between nuclear rDNA and mtDNA phylogenies, relationships among certain major clades are different. In this study we report that mtDNA sequences do not support the monophyly of Ascaridida, Oxyurida and Spirurida (clade III) in contrast to results for nuclear rDNA. Results from mtDNA genomes show promise as an additional independently evolving genome for developing phylogenetic hypotheses for nematodes, although substantially increased taxon sampling is needed for enhanced comparative value with nuclear rDNA. Ultimately, topological incongruence (and congruence) between nuclear rDNA and mtDNA phylogenetic hypotheses will need to be tested relative to additional independent loci that provide appropriate levels of resolution. For this comparative phylogenetic study, we determined the complete mitochondrial genome sequences of three nematode species, Cucullanus robustus (13,972 bp) representing Ascaridida, Wellcomia siamensis (14,128 bp) representing Oxyurida, and Heliconema longissimum (13,610 bp) representing Spirurida. These new sequences were used along with 33 published nematode mitochondrial genomes to investigate phylogenetic relationships among chromadorean orders. Phylogenetic analyses of both nucleotide and amino acid sequence datasets support the hypothesis that Ascaridida is nested within Rhabditida. The position of Oxyurida within Chromadorea varies among analyses; in most analyses this order is sister to the Ascaridida plus Rhabditida clade, with representative Spirurida forming a distinct clade, however, in one case Oxyurida is sister to Spirurida. Ascaridida, Oxyurida, and Spirurida (the sampled clade III taxa) do not form a monophyletic group based on complete mitochondrial DNA sequences. Tree topology tests revealed that constraining clade III taxa to be monophyletic, given the mtDNA datasets analyzed, was a significantly worse result. The phylogenetic hypotheses from comparative analysis of the complete mitochondrial genome data (analysis of nucleotide and amino acid datasets, and nucleotide data excluding 3rd positions) indicates that nematodes representing Ascaridida, Oxyurida and Spirurida do not share an exclusive most recent common ancestor, in contrast to published results based on nuclear ribosomal DNA. Overall, mtDNA genome data provides reliable support for nematode relationships that often corroborates findings based on nuclear rDNA. It is anticipated that additional taxonomic sampling will provide a wealth of information on mitochondrial genome evolution and sequence data for developing phylogenetic hypotheses for the phylum Nematoda.
-
the mitochondrial genome sequence of enterobius vermicularis nematoda oxyurida an idiosyncratic gene order and phylogenetic information for chromadorean nematodes
Gene, 2009Co-Authors: Seokha Kang, Steven A. Nadler, Tahera Sultana, Keeseon S Eom, Yung Chul Park, Nathan Soonthornpong, Joongki ParkAbstract:The complete mitochondrial genome sequence was determined for the human pinworm Enterobius vermicularis (Oxyurida: Nematoda) and used to infer its phylogenetic relationship to other major groups of chromadorean nematodes. The E. vermicularis genome is a 14,010-bp circular DNA molecule that encodes 36 genes (12 proteins, 22 tRNAs, and 2 rRNAs). This mtDNA genome lacks atp8, as reported for almost all other nematode species investigated. Phylogenetic analyses (maximum parsimony, maximum likelihood, neighbor joining, and Bayesian inference) of nucleotide sequences for the 12 protein-coding genes of 25 nematode species placed E. vermicularis, a representative of the order Oxyurida, as sister to the main Ascaridida+Rhabditida group. Tree topology comparisons using statistical tests rejected an alternative hypothesis favoring a closer relationship among Ascaridida, Spirurida, and Oxyurida, which has been supported from most studies based on nuclear ribosomal DNA sequences. Unlike the relatively conserved gene arrangement found for most chromadorean taxa, E. vermicularis mtDNA gene order is very unique, not sharing similarity to any other nematode species reported to date. This lack of gene order similarity may represent idiosyncratic gene rearrangements unique to this specific lineage of the oxyurids. To more fully understand the extent of gene rearrangement and its evolutionary significance within the nematode phylogenetic framework, additional mitochondrial genomes representing a greater evolutionary diversity of species must be characterized.
-
Molecular phylogeny of clade III nematodes reveals multiple origins of tissue parasitism.
Parasitology, 2007Co-Authors: Steven A. Nadler, Ramon A. Carreno, Hugo H. Mejía-madrid, J. Ullberg, Christopher Pagan, R. Houston, Jean-pierre HugotAbstract:Molecular phylogenetic analyses of 113 taxa representing Ascaridida, Rhigonematida, Spirurida and Oxyurida were used to infer a more comprehensive phylogenetic hypothesis for representatives of 'clade III'. The posterior probability of multiple alignment sites was used to exclude or weight characters, yielding datasets that were analysed using maximum parsimony, likelihood, and Bayesian inference methods. Phylogenetic results were robust to differences among inference methods for most high-level taxonomic groups, but some clades were sensitive to treatments of characters reflecting differences in alignment ambiguity. Taxa representing Camallanoidea, Oxyurida, Physalopteroidea, RaphidAscarididae, and Skrjabillanidae were monophyletic in all 9 analyses whereas Ascaridida, Ascarididae, Anisakidae, Cosmocercoidea, Habronematoidea, Heterocheilidae, Philometridae, Rhigonematida and Thelazioidea were never monophyletic. Some clades recovered in all trees such as Dracunculoidea and Spirurina included the vast majority of their sampled species, but were non-monophyletic due to the consistent behaviour of one or few 'rogue' taxa. Similarly, 102 of 103 clade III taxa were strongly supported as monophyletic, yet clade III was paraphyletic due to the grouping of Truttaedacnitis truttae with the outgroups. Mapping of host 'habitat' revealed that tissue-dwelling localization of nematode adults has evolved independently at least 3 times, and relationships among Spirurina and Camallanina often reflected tissue predilection rather than taxonomy.
Annunziata Giangaspero - One of the best experts on this subject based on the ideXlab platform.
-
Epidemiology and biology of nematodofauna affecting Testudo hermanni, Testudo graeca and Testudo marginata in Italy
Parasitology Research, 2005Co-Authors: Donato Traversa, Gioia Capelli, Raffaella Iorio, Salah Bouamer, Angelo Cameli, Annunziata GiangasperoAbstract:Tortoises of the genus Testudo living in Italy are Testudo hermanni , Testudo graeca and Testudo marginata . Although a great deal of information has been acquired on the internal medicine and surgery on these animals, little is known of their parasitological fauna. A survey on the presence of gastro-intestinal parasitic nematodes in tortoises bred in Italy was carried out to acquire extensive epidemiological data. Stool samples of 62 tortoises (37 T. hermanni hermanni , 13 T. graeca , 6 T. hermanni boettgeri and 6 T. marginata ) were macroscopically examined and subjected to qualitative (flotation and Baermann techniques) and quantitative (McMaster technique) microscopic examinations. Adult nematodes were identified using morphological keys. Eggs of oxyurids (species indistinguishable) and adults of Alaeuris numidica , Mehdiella microstoma , Mehdiella uncinata , Tachygonetria longicollis , Tachygonetria conica and Tachygonetria palearcticus (Oxyurida, Pharyngodonidae); larvae and adults of Atractis dactyluris (Ascaridida, Atractidae); and eggs and adults of Angusticaecum holopterum (Ascaridida, Ascarididae) were identified in all animals >1 year, whereas all tortoises
