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BMC Ecology and Evolution Jun 202118S rRNA is a major component of the small subunit of the eukaryotic ribosome and an important phylogenetic marker for many groups, often to the point of being the only...
BACKGROUND
18S rRNA is a major component of the small subunit of the eukaryotic ribosome and an important phylogenetic marker for many groups, often to the point of being the only marker available for some. A core structure across eukaryotes exists for this molecule that can help to inform about its evolution in different groups. Using an alignment of 18S rDNA for Rotifera as traditionally recognized (=Bdelloidea, Monogononta, and Seisonacea, but not Acanthocephala), I fitted sequences for three exemplar species (Adineta vaga, Brachionus plicatilis, and Seison nebaliae, respectively) to the core structure and used these maps to reveal patterns of evolution for the remainder of this diverse group of microscopic animals.
RESULTS
The obtained variability maps of the 18S rRNA molecule revealed a pattern of high diversity among the three major rotifer clades coupled with strong conservation within each of bdelloids and monogononts. A majority of individual sites (ca. 60%) were constant even across rotifers as a whole with variable sites showing only intermediate rates of evolution. Although the three structural maps each showed good agreement with the inferred core structure for eukaryotic 18S rRNA and so were highly similar to one another at the secondary and tertiary levels, the overall pattern is of three highly distinct, but conserved motifs within the group at the primary sequence level. A novel finding was that of a variably expressed deletion at the 3' end of the V3 hypervariable region among some bdelloid species that occasionally extended into and included the pseudoknot structure following this region as well as the central "square" of the 18S rRNA molecule. Compared to other groups, levels of variation and rates of evolution for 18S rRNA in Rotifera roughly matched those for Gastropoda and Acanthocephala, despite increasing evidence for the latter being a clade within Rotifera.
CONCLUSIONS
The lack of comparative data for comparable groups makes interpretation of the results (i.e., very low variation within each of the three major rotifer clades, but high variation between them) and their potential novelty difficult. However, these findings in combination with the high morphological diversity within rotifers potentially help to explain why no clear consensus has been reached to date with regard to the phylogenetic relationships among the major groups.
Topics: Acanthocephala; Animals; Evolution, Molecular; Phylogeny; RNA, Ribosomal, 18S; Rotifera
PubMed: 34112085
DOI: 10.1186/s12862-021-01845-2 -
Parasitology Sep 2021Post-mortem examination of a fin whale Balaenoptera physalus stranded in the Mediterranean Sea led to the finding of Bolbosoma balaenae for the first time in this basin....
Post-mortem examination of a fin whale Balaenoptera physalus stranded in the Mediterranean Sea led to the finding of Bolbosoma balaenae for the first time in this basin. In this work, we describe new structural characteristics of this parasite using light microscopy and scanning electron microscopy approaches. Moreover, the molecular and phylogenetic data as inferred from both ribosomal RNA 18S-28S and the mitochondrial DNA cytochrome oxidase c subunit 1 (cox1) for adult specimens of B. balaenae are also reported for the first time. Details of the surface topography such as proboscis's hooks, trunked trunk spines of the prebulbar foretrunk, ultrastructure of proboscis's hooks and micropores of the tegument are shown. The 18S + 28S rRNA Bayesian tree (BI) as inferred from the phylogenetic analysis showed poorly resolved relationships among the species of Bolbosoma. In contrast, the combined 18S + 28S + mtDNA cox1 BI tree topology showed that the present sequences clustered with the species of Bolbosoma in a well-supported clade. The comparison of cox1 and 18S sequences revealed that the present specimens are conspecific with the cystacanths of B. balaenae previously collected in the euphausiid Nyctiphanes couchii from the North Eastern Atlantic Ocean. This study provided taxonomic, molecular and phylogenetic data that allow for a better characterization of this poor known parasite.
Topics: Acanthocephala; Animals; Autopsy; Bayes Theorem; Cyclooxygenase 1; DNA, Mitochondrial; Duodenum; Female; Fin Whale; Helminthiasis, Animal; Italy; Male; Mediterranean Sea; Microscopy, Electron, Scanning; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 18S; RNA, Ribosomal, 28S
PubMed: 34100350
DOI: 10.1017/S0031182021000925 -
Journal of Clinical Microbiology Oct 2021Acanthocephala is a phylum of parasitic pseudocoelomates that infect a wide range of vertebrate and invertebrate hosts and can cause zoonotic infections in humans. The... (Review)
Review
Acanthocephala is a phylum of parasitic pseudocoelomates that infect a wide range of vertebrate and invertebrate hosts and can cause zoonotic infections in humans. The zoologic literature is quite rich and diverse; however, the human-centric literature is sparse, with sporadic reports over the past 70 years. Causal agents of acanthocephaliasis in humans are reviewed as well as their biology and life cycle. This review provides the first consolidated and summarized report of human cases of acanthocephaliasis based on English language publications, including epidemiology, clinical presentation, treatment, and diagnosis and identification.
Topics: Acanthocephala; Animals; Helminthiasis; Host-Parasite Interactions; Humans; Intestinal Diseases, Parasitic; Parasites
PubMed: 34076470
DOI: 10.1128/JCM.02691-20 -
Parasitology Aug 2021Parasite infracommunities tend to be stochastic in nature, although environmental characteristics such as the type of water source in streams and host traits can have an...
Parasite infracommunities tend to be stochastic in nature, although environmental characteristics such as the type of water source in streams and host traits can have an effect on the biotic assemblages and by extension the parasite fauna. We examined the effect of water source and the rate of adult fish migration on the metazoan parasite infracommunities of conspecific juvenile brown trout, Salmo trutta L. among streams flowing into Lake Lucerne (Switzerland). Juvenile (1 to 2-year old) fish harboured higher parasite species richness in groundwater-fed than in surface water-fed streams, whereas the rate of fish migration did not affect infracommunity richness. Heteroxenous species were more common in groundwater-fed streams with high and medium rates of trout migration, whereas infracommunities in surface water-fed streams and streams with low rates of fish migration were dominated by one monoxenous parasite or lacked infections. Similarity in the parasite infracommunity composition of juvenile trout across streams was explained by the interaction between type of water source and adult migration rates. Our conclusions support that similarity in the parasite composition of resident freshwater conspecifics can be predicted by the local environmental settings and host migratory behaviour, whereas parasite richness is mainly influenced by the environmental characteristics.
Topics: Acanthocephala; Animal Migration; Animals; Biodiversity; Cestoda; Cestode Infections; Helminthiasis, Animal; Helminths; Prevalence; Rivers; Switzerland; Trematoda; Trematode Infections; Trout
PubMed: 34027845
DOI: 10.1017/S0031182021000780 -
Heliyon Apr 2021In this work we report from Patagonia, Argentina. Specimens were collected from the small intestine of a charadriid shorebird with Neotropical distribution, the...
In this work we report from Patagonia, Argentina. Specimens were collected from the small intestine of a charadriid shorebird with Neotropical distribution, the Two-banded Plover (). Both morphological and molecular characterization, plus pathological aspect of this species is provided. is characterized by having a proboscis with 18-20 longitudinal rows of hooks and 11-14 hooks per row. Sequences of the small subunit (SSU) and large subunit (LSU) of the nuclear ribosomal DNA were obtained and compared with other sequences available in GenBank. Phylogenetic analyses inferred with each molecular marker consistently showed that is sister taxa to , a parasite of the long-billed curlew () from northern Mexico. Pathologic findings associated with the parasites include ulcerative enteritis, granulomatous inflammation, diffuse lymphocytic infiltration, serositis, and peritonitis. This record expands the host and geographical record of ., provide baseline information on its pathological aspects, and represents the first molecular characterization of in the Neotropics.
PubMed: 33898805
DOI: 10.1016/j.heliyon.2021.e06628 -
Revista Brasileira de Parasitologia... 2021As the second-largest Neotropical carnivore, cougars (Puma concolor) are especially important for maintenance of the biodiversity and ecosystem health. Five wild adult...
As the second-largest Neotropical carnivore, cougars (Puma concolor) are especially important for maintenance of the biodiversity and ecosystem health. Five wild adult cougars (Puma concolor), found roadkilled in highways in the Northeastern region of São Paulo, were evaluated in search for parasites. Ten species representing nine families were identified. The most prevalent helminths were Uncinaria bidens, Lagochilascaris major, Spirometra sp., and Oncicola canis, followed by Cylicospirura subaequalis, Toxascaris leonina, Taenia omissa, Echinococcus sp., Filaroides sp. and Oncicola oncicola. It is important to note that some helminths found in this study, such as L. major, Spirometra sp., O. oncicola, O. canis, Echinococcus sp., T. leonina, C. subaequalis, and Filaroides sp. are known to affect domestic carnivores, which may indicate interaction between wild and domestic hosts. This study represents a new host record for four of the species found in cougars, U. bidens, L. major, O. canis, and Filaroides sp., and new locality records for U. bidens, T. leonina, C. subaequalis, and Filaroides sp.
Topics: Acanthocephala; Animals; Brazil; Ecosystem; Helminths; Puma
PubMed: 33787736
DOI: 10.1590/S1984-29612021008 -
Proceedings. Biological Sciences Mar 2021Parasitic worms (i.e. helminths) commonly infect multiple hosts in succession before reproducing. At each life cycle step, worms may fail to infect the next host, and...
Parasitic worms (i.e. helminths) commonly infect multiple hosts in succession before reproducing. At each life cycle step, worms may fail to infect the next host, and this risk accumulates as life cycles include more successive hosts. Risk accumulation can be minimized by having high establishment success in the next host, but comparisons of establishment probabilities across parasite life stages are lacking. We compiled recovery rates (i.e. the proportion of parasites recovered from an administered dose) from experimental infections with acanthocephalans, cestodes and nematodes. Our data covered 127 helminth species and 16 913 exposed hosts. Recovery rates increased with life cycle progression (11%, 29% and 46% in first, second and third hosts, respectively), because larger worm larvae had higher recovery, both within and across life stages. Recovery declined in bigger hosts but less than it increased with worm size. Higher doses were used in systems with lower recovery, suggesting that high doses are chosen when few worms are expected to establish infection. Our results indicate that growing in the small and short-lived hosts at the start of a complex life cycle, though dangerous, may substantially improve parasites' chances of completing their life cycles.
Topics: Acanthocephala; Animals; Helminths; Host-Parasite Interactions; Life Cycle Stages; Nematoda
PubMed: 33726588
DOI: 10.1098/rspb.2021.0142 -
Iranian Journal of Veterinary Research 2020is a parasite from the Acanthocephala phylum with worldwide distribution. parasites are found in pinnipeds as their definitive host.
BACKGROUND
is a parasite from the Acanthocephala phylum with worldwide distribution. parasites are found in pinnipeds as their definitive host.
AIMS
This study aimed to investigate the morphological and molecular characteristics of , and its histopathological effect on the intestinal tissue of .
METHODS
A severe infection was observed in the small intestine of a juvenile male Caspian seal (). The morphological descriptions were done using light microscopy, and scanning electron microscopy (SEM). The molecular diagnosis was performed using partial sequences of internal transcribed spacer 1 (ITS1) and 5.8S ribosomal RNA () gene.
RESULTS
According to the results, the specimens were identified as The histopathological inspection of intestinal tissue revealed lesions in epithelial cells, mucosa, submucosa and muscle layers, destruction of intestinal glands, and infiltration of inflammatory cells.
CONCLUSION
Presence of such a severe infection in one of the individual Caspian seals can suggest the possibility of morbidity among other seals in the landlocked Caspian Sea. Thus, further research on their parasite infections is required for understating the status of the Caspian seal population and conserving this endangered species.
PubMed: 33584844
DOI: No ID Found -
Parasitology Apr 2021Identifying the factors that structure host–parasite interactions is fundamental to understand the drivers of species distributions and to predict novel cross-species...
Identifying the factors that structure host–parasite interactions is fundamental to understand the drivers of species distributions and to predict novel cross-species transmission events. More phylogenetically related host species tend to have more similar parasite associations, but parasite specificity may vary as a function of transmission mode, parasite taxonomy or life history. Accordingly, analyses that attempt to infer host−parasite associations using combined data on different parasite groups may perform quite differently relative to analyses on each parasite subset. In essence, are more data always better when predicting host−parasite associations, or does parasite taxonomic resolution matter? Here, we explore how taxonomic resolution affects predictive models of host−parasite associations using the London Natural History Museum's database of host–helminth interactions. Using boosted regression trees, we demonstrate that taxon-specific models (i.e. of Acanthocephalans, Nematodes and Platyhelminthes) consistently outperform full models in predicting mammal-helminth associations. At finer spatial resolutions, full and taxon-specific model performance does not vary, suggesting tradeoffs between phylogenetic and spatial scales of analysis. Although all models identify similar host and parasite covariates as important to such patterns, our results emphasize the importance of phylogenetic scale in the study of host–parasite interactions and suggest that using taxonomic subsets of data may improve predictions of parasite distributions and cross-species transmission. Predictive models of host–pathogen interactions should thus attempt to encompass the spatial resolution and phylogenetic scale desired for inference and prediction and potentially use model averaging or ensemble models to combine predictions from separately trained models.
Topics: Acanthocephala; Animals; Host-Parasite Interactions; Mammals; Models, Biological; Nematoda; Phylogeny; Platyhelminths; Spatial Analysis
PubMed: 33342442
DOI: 10.1017/S0031182020002371 -
Scientific Reports Dec 2020Multimodal warning displays often pair one signal modality (odor) with a second modality (color) to avoid predation. Experiments with bird predators suggest these signal...
Multimodal warning displays often pair one signal modality (odor) with a second modality (color) to avoid predation. Experiments with bird predators suggest these signal components interact synergistically, with aversive odors triggering otherwise hidden aversions to particular prey colors. In a recent study, this phenomenon was found in a jumping spider (Habronattus trimaculatus), with the defensive odor from a coreid bug (Acanthocephala femorata) triggering an aversion to red. Here, we explore how generalizable this phenomenon is by giving H. trimaculatus the choice between red or black prey in the presence or absence of defensive odors secreted from (1) eastern leaf-footed bugs (Leptoglossus phyllopus, Hemiptera), (2) grass stinkbugs (Mormidea pama, Hemiptera), (3) Asian ladybird beetles (Harmonia axyridis, Coleoptera), and (4) eastern lubber grasshoppers (Romalea microptera, Orthoptera). As expected, in the presence of the hemipteran odors, spiders were less likely to attack red prey (compared to no odor). Unexpectedly, the beetle and grasshopper odors did not bias spiders away from red. Our results with the hemipteran odors were unique to red; follow-up experiments indicated that these odors did not affect biases for/against green prey. We discuss our findings in the context of generalized predator foraging behavior and the functions of multimodal warning displays.
Topics: Animals; Coleoptera; Grasshoppers; Hemiptera; Models, Biological; Odorants; Pigmentation; Spiders
PubMed: 33318578
DOI: 10.1038/s41598-020-78952-5