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Current Biology : CB Sep 2011Parasites and parasitism is common. Worm macroparasites have evolved life-history traits that allow them to successfully transmit between spatially and temporally... (Review)
Review
Parasites and parasitism is common. Worm macroparasites have evolved life-history traits that allow them to successfully transmit between spatially and temporally separated patches of host resource and to survive within these environments. Macroparasites have common life-history strategies to achieve this, but these general themes are modified in a myriad of ways related to the specific biology of their hosts. Parasite life histories are also dynamic, responding to conditions inside and outside of hosts, and they continue to evolve, especially in response to our attempts to control them and the harm that they cause.
Topics: Adaptation, Physiological; Animals; Biological Evolution; Host-Parasite Interactions; Life Cycle Stages; Nematoda; Parasites; Platyhelminths; Reproduction
PubMed: 21959167
DOI: 10.1016/j.cub.2011.07.023 -
The International Journal of... 2018Understanding the process of regeneration has been one of the longstanding scientific aims, from a fundamental biological perspective, as well as within the applied... (Review)
Review
Understanding the process of regeneration has been one of the longstanding scientific aims, from a fundamental biological perspective, as well as within the applied context of regenerative medicine. Because regeneration competence varies greatly between organisms, it is essential to investigate different experimental animals. The free-living marine flatworm Macrostomum lignano is a rising model organism for this type of research, and its power stems from a unique set of biological properties combined with amenability to experimental manipulation. The biological properties of interest include production of single-cell fertilized eggs, a transparent body, small size, short generation time, ease of culture, the presence of a pluripotent stem cell population, and a large regeneration competence. These features sparked the development of molecular tools and resources for this animal, including high-quality genome and transcriptome assemblies, gene knockdown, in situ hybridization, and transgenesis. Importantly, M. lignano is currently the only flatworm species for which transgenesis methods are established. This review summarizes biological features of M. lignano and recent technological advances towards experimentation with this animal. In addition, we discuss the experimental potential of this model organism for different research questions related to regeneration and stem cell biology.
Topics: Animals; Developmental Biology; Genome, Helminth; Models, Animal; Phylogeny; Platyhelminths; Pluripotent Stem Cells; Regeneration; Transcriptome
PubMed: 29938766
DOI: 10.1387/ijdb.180077eb -
The International Journal of... 2014
Topics: Animals; Annelida; Bryozoa; Developmental Biology; Embryo, Nonmammalian; Mollusca; Platyhelminths
PubMed: 25690956
DOI: 10.1387/ijdb.140289jh -
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 -
Parasitology Dec 2022The tapeworms of fishes (Chondrichthyes and Actinopterygii) account one-third (1670 from around 5000) of the total tapeworm (Platyhelminthes: Cestoda) species diversity.... (Review)
Review
The tapeworms of fishes (Chondrichthyes and Actinopterygii) account one-third (1670 from around 5000) of the total tapeworm (Platyhelminthes: Cestoda) species diversity. In total 1186 species from 9 orders occur as adults in elasmobranchs (sharks, rays and chimaeras), and 484 species from 8 orders mature in ray-finned fishes (referred to here as teleosts). Teleost tapeworms are dominated by freshwater species (78%), but only 3% of elasmobranch tapeworms are known from freshwater rays of South America and Asia (Borneo). In the last 2 decades, vast progress has been made in understanding species diversity, host associations and interrelationships among fish tapeworms. In total, 172 new species have been described since 2017 (149 from elasmobranchs and 23 from teleosts; invalidly described taxa are not included, especially those from the Oriental region). Molecular data, however, largely limited to a few molecular markers (mainly 28S rDNA, but also 18S and 1), are available for about 40% of fish tapeworm species. They allowed us to significantly improve our understanding of their interrelationships, including proposals of a new, more natural classification at the higher-taxonomy level (orders and families) as well as at the lower-taxonomy level (genera). In this review, we summarize the main advances and provide perspectives for future research.
Topics: Animals; Phylogeny; Cestoda; Cestode Infections; Elasmobranchii; Diphyllobothrium; Fishes; Fish Diseases
PubMed: 36004800
DOI: 10.1017/S0031182022001202 -
PloS One 2019Microstomidae (Platyhelminthes: Macrostomorpha) diversity has been almost entirely ignored within recent years, likely due to inconsistent and often old taxonomic... (Review)
Review
Microstomidae (Platyhelminthes: Macrostomorpha) diversity has been almost entirely ignored within recent years, likely due to inconsistent and often old taxonomic literature and a general rarity of sexually mature collected specimens. Herein, we reconstruct the phylogenetic relationships of the group using both previously published and new 18S and CO1 gene sequences. We present some taxonomic revisions of Microstomidae and further describe 8 new species of Microstomum based on both molecular and morphological evidence. Finally, we briefly review the morphological taxonomy of each species and provide a key to aid in future research and identification that is not dependent on reproductive morphology. Our goal is to clarify the taxonomy and facilitate future research into an otherwise very understudied group of tiny (but important) flatworms.
Topics: Animals; DNA, Helminth; Phylogeny; Platyhelminths; Reproduction
PubMed: 31017906
DOI: 10.1371/journal.pone.0212073 -
PLoS Pathogens Jan 2018Schistosomes are blood-dwelling trematodes with global impact on human and animal health. Because medical treatment is currently based on a single drug, praziquantel,... (Review)
Review
Schistosomes are blood-dwelling trematodes with global impact on human and animal health. Because medical treatment is currently based on a single drug, praziquantel, there is urgent need for the development of alternative control strategies. The Schistosoma mansoni genome project provides a platform to study and connect the genetic repertoire of schistosomes to specific biological functions essential for successful parasitism. G protein-coupled receptors (GPCRs) form the largest superfamily of transmembrane receptors throughout the Eumetazoan phyla, including platyhelminths. Due to their involvement in diverse biological processes, their pharmacological importance, and proven druggability, GPCRs are promising targets for new anthelmintics. However, to identify candidate receptors, a more detailed understanding of the roles of GPCR signalling in schistosome biology is essential. An updated phylogenetic analysis of the S. mansoni GPCR genome (GPCRome) is presented, facilitated by updated genome data that allowed a more precise annotation of GPCRs. Additionally, we review the current knowledge on GPCR signalling in this parasite and provide new insights into the potential roles of GPCRs in schistosome reproduction based on the findings of a recent tissue-specific transcriptomic study in paired and unpaired S. mansoni. According to the current analysis, GPCRs contribute to gonad-specific functions but also to nongonad, pairing-dependent processes. The latter may regulate gonad-unrelated functions during the multifaceted male-female interaction. Finally, we compare the schistosome GPCRome to that of another parasitic trematode, Fasciola, and discuss the importance of GPCRs to basic and applied research. Phylogenetic analyses display GPCR diversity in free-living and parasitic platyhelminths and suggest diverse functions in schistosomes. Although their roles need to be substantiated by functional studies in the future, the data support the selection of GPCR candidates for basic and applied studies, invigorating the exploitation of this important receptor class for drug discovery against schistosomes but also other trematodes.
Topics: Animals; Antiplatyhelmintic Agents; Fasciola; G-Protein-Coupled Receptor Kinases; Gene Expression Profiling; Genome, Helminth; Genomics; Helminth Proteins; Humans; Models, Biological; Organ Specificity; Phylogeny; Protein Kinase Inhibitors; Schistosoma mansoni; Signal Transduction
PubMed: 29346437
DOI: 10.1371/journal.ppat.1006718 -
Philosophical Transactions of the Royal... Apr 2008Molecular approaches to the study of development and evolution have had profound effects on our understanding of the nature of the evolutionary process. Developmental... (Review)
Review
Molecular approaches to the study of development and evolution have had profound effects on our understanding of the nature of the evolutionary process. Developmental biologists became intoxicated with fanciful notions of reconstructing genetic pathways of morphogenesis while evolutionary biologists were sobered by the fallacy of reconstructing organismal relationships along increasing grades of morphological complexity. Increased taxon sampling and improvements in analytical techniques are providing a new approach and are forcing biologists to move past historical biases to allow more accurate mapping of morphological and developmental characters through evolutionary time. Here, we discuss the possible developmental and morphological features of the 'urbilaterian', the triploblastic animal with anterior-posterior and dorsoventral axes and predecessor of the protostome-deuterostome ancestor. We argue that this animal, with features resembling acoelomorph flatworms, was far simpler morphologically than the protostome-deuterostome ancestor despite possessing a nearly complete eubilaterian genome. We show that the deployment of some genes expected to pattern the protostome-deuterostome ancestor is not deployed in acoels in the predicted manner and thus might have been co-opted after the evolution of the urbilaterian. We also identify the developmental changes related to gastrulation that gave rise to the urbilaterian from a simpler cnidarian-like ancestor.
Topics: Animals; Biological Evolution; Body Patterning; Developmental Biology; Evolution, Molecular; Female; Gastrulation; Male; Models, Biological; Phylogeny; Platyhelminths
PubMed: 18192185
DOI: 10.1098/rstb.2007.2239 -
Molecular and Cellular Endocrinology Mar 2011Nuclear receptors (NRs) belong to a large protein superfamily that are important transcriptional modulators in metazoans. Parasitic helminths include parasitic worms... (Review)
Review
Nuclear receptors (NRs) belong to a large protein superfamily that are important transcriptional modulators in metazoans. Parasitic helminths include parasitic worms from the Lophotrochozoa (Platyhelminths) and Ecdysozoa (Nematoda). NRs in parasitic helminths diverged into two different evolutionary lineages. NRs in parasitic Platyhelminths have orthologues in Deuterostomes, in arthropods or both with a feature of extensive gene loss and gene duplication within different gene groups. NRs in parasitic Nematoda follow the nematode evolutionary lineage with a feature of multiple duplication of SupNRs and gene loss.
Topics: Amino Acid Sequence; Animals; DNA-Binding Proteins; Gene Deletion; Gene Duplication; Molecular Sequence Data; Nematoda; Phylogeny; Platyhelminths; Protein Structure, Tertiary; Receptors, Cytoplasmic and Nuclear; Sequence Homology
PubMed: 20600585
DOI: 10.1016/j.mce.2010.06.011 -
Parasitology Sep 2022The food-borne trematodes, and , are classified as group 1 biological carcinogens: definitive causes of cancer. By contrast, infections with , also a food-borne... (Review)
Review
The food-borne trematodes, and , are classified as group 1 biological carcinogens: definitive causes of cancer. By contrast, infections with , also a food-borne trematode of the phylum Platyhelminthes, are not carcinogenic. This review explores the premise that the differential activation of macrophages during infection with these food-borne trematodes is a major determinant of the pathological outcome of infection. Like most helminths, the latter stages of infection with all 3 flukes induce M2 macrophages, a phenotype that mediates the functional repair of tissue damaged by the feeding and migratory activities of the parasites. However, there is a critical difference in how the development of pro-inflammatory M1 macrophages is regulated during infection with these parasites. While the activation of the M1 macrophage phenotype is largely suppressed during the early stages of infection with , M1 macrophages predominate in the bile ducts following infection with and . The anti-microbial factors released by M1 macrophages create an environment conducive to mutagenesis, and hence the initiation of tumour formation. Subsequently, the tissue remodelling processes induced by the M2 macrophages promote the proliferation of mutated cells, and the expansion of cancerous tissue. This review will also explore the interactions between macrophages and parasite-derived signals, and their contributions to the stark differences in the innate immune responses to infection with these parasites.
Topics: Animals; Clonorchis sinensis; Fasciola hepatica; Fascioliasis; Macrophages; Opisthorchis; Parasites
PubMed: 35621040
DOI: 10.1017/S0031182022000749