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Parasitology International Dec 2013Schistosomiasis, a neglected tropical disease affecting hundreds of millions, is caused by parasitic flatworms of the genus Schistosoma. Treatment and control of... (Review)
Review
Schistosomiasis, a neglected tropical disease affecting hundreds of millions, is caused by parasitic flatworms of the genus Schistosoma. Treatment and control of schistosomiasis relies almost exclusively on a single drug, praziquantel (PZQ), a dangerous situation for a disease of this magnitude. Though PZQ is highly effective overall, it has drawbacks, and reports of worms showing PZQ resistance, either induced in the laboratory or isolated from the field, are disconcerting. Multidrug transporters underlie multidrug resistance (MDR), a phenomenon in which resistance to a single drug is accompanied by unexpected cross-resistance to several structurally unrelated compounds. Some of the best studied multidrug transporters are members of the ancient and very large ATP-binding cassette (ABC) superfamily of efflux transporters. ABC multidrug transporters such as P-glycoprotein (Pgp; ABCB1) are also associated with drug resistance in parasites, including helminths such as schistosomes. In addition to their association with drug resistance, however, ABC transporters also function in a wide variety of physiological processes in metazoans. In this review, we examine recent studies that help define the role of schistosome ABC transporters in regulating drug susceptibility, and in normal schistosome physiology, including reproduction and excretory activity. We postulate that schistosome ABC transporters could be useful targets for compounds that enhance the effectiveness of current therapeutics as well as for agents that act as antischistosomals on their own.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP-Binding Cassette Transporters; Animals; Drug Resistance; Helminthiasis; Models, Molecular; Platyhelminths; Protein Structure, Tertiary; Schistosoma; Schistosomiasis
PubMed: 23474413
DOI: 10.1016/j.parint.2013.02.006 -
Parasitology Nov 2022The complete circular mitogenome of (Platyhelminthes: Paragonimidae) from Japan, obtained by PacBio long-read sequencing, was 17 591 bp and contained 12 protein-coding...
The complete circular mitogenome of (Platyhelminthes: Paragonimidae) from Japan, obtained by PacBio long-read sequencing, was 17 591 bp and contained 12 protein-coding genes (PCGs), 2 mitoribosomal RNA and 22 transfer RNA genes. The 8 gene was absent, and there was a 40 bp overlap between 4L and 4. The long non-coding region (4.3 kb) included distinct types of long and short repeat units. The pattern of base usage for PCGs and the mtDNA coding region overall in Asian and American species (, , and ) and the Indian form of was > > > . On the other hand, East-Asian used > > > . Five Asian and American species and had TTT/Phe, TTG/Leu and GTT/Val as the most frequently used codons, whereas the least-used codons were different in each species and between regional forms of . The phylogenetic tree reconstructed from a concatenated alignment of amino acids of 12 PCGs from 36 strains/26 species/5 families of trematodes confirmed that the Paragonimidae is monophyletic, with 100% nodal support. was resolved as a sister to The clade was clearly separate from remaining congeners. The latter clade was comprised of 2 subclades, one of the East-Asian and the other of the Indian Type 1 samples. Additional mitogenomes in the Paragonimidae are needed for genomic characterization and are useful for diagnostics, identification and genetic/ phylogenetic/ epidemiological/ evolutionary studies of the Paragonimidae.
Topics: Animals; Paragonimus; Genome, Mitochondrial; Phylogeny; Trematoda; Lung
PubMed: 36101009
DOI: 10.1017/S0031182022001184 -
Brazilian Journal of Biology = Revista... Jun 2016Microturbellarians typically belong to the benthos and may occur in a wide variety of environments. They are abundant in freshwater and marine ecosystems and may occur...
Microturbellarians typically belong to the benthos and may occur in a wide variety of environments. They are abundant in freshwater and marine ecosystems and may occur in moist terrestrial habitats. However, turbellarians are seldom taken into account in studies of biodiversity. Most studies on Brazilian microturbellarians had taxonomical purposes and were done in the years 1940-1950. Thus, information on their occurrence and ecological aspects are dispersed throughout several papers. We intend here to summarize the biogeographical distribution and ecological aspects of microturbellarians recorded for Brazil, indicating the main gaps in their knowledge and possible actions to enhance studies on this group. There are 239 species of microturbellarians registered for Brazil, with records distributed in 12 states. However, just three states located in southern Brazil have records of 94% of microturbellarian species. Thus, knowledge on the systematics and geographical distribution of Brazilian microturbellarians clearly reflect the scientific activity over many years or decades in two states of southeastern and southern Brazil. Considering the scant information on this group in Brazil, which is also the situation of the Neotropical microturbellarians in general, some actions should be proposed. First, it would be necessary to sample in the diverse biomes, as well as in the various river and sea basins, based on standardized sampling protocols. Second, it would be necessary to encourage diverse research groups to include microturbellarians and/or turbellarians in general into biodiversity inventories and studies on community structure of invertebrates. Third, it is necessary to increase the number of research groups on microturbellarians, in order to augment the studies on their morphology, systematics, and ecology. Considering their abundance, species richness and ecological importance in aquatic environments, despite some peculiarities regarding their sampling, sorting and identification procedures, the challenge to study microturbellarians and enhance knowledge about them in Brazilian ecosystems should be faced.
Topics: Animals; Biodiversity; Brazil; Ecological and Environmental Phenomena; Ecosystem; Fresh Water; Hydrobiology; Invertebrates; Rivers; Turbellaria
PubMed: 26959945
DOI: 10.1590/1519-6984.21514 -
Biology Letters Jan 2024While knowledge of early ontogeny in abyssal animals is highly limited in general, it was completely lacking for abyssal, free-living platyhelminths. We discovered...
While knowledge of early ontogeny in abyssal animals is highly limited in general, it was completely lacking for abyssal, free-living platyhelminths. We discovered flatworm egg capsules (or 'cocoons') on rocks collected at depths of 6176-6200 m on the abyssal slope of the Kuril-Kamchatka Trench, northwestern Pacific. The egg capsules were black and spherical, around 3 mm in diameter, and contained three to seven individuals ( = 4) at the same developmental stage, either the spherical (putative early embryo) or vermiform (putative late embryo) stages. A molecular phylogenetic analysis based on 18S and 28S rRNA sequences revealed that the flatworms belong in suborder Maricola in Tricladida and suggested that they may have colonized from shallow to deep waters. This study provides the deepest record for free-living flatworms and the first information on their early life stages in the abyssal zone, which were very similar to those in shallow-water forms. This similarity in development between the relatively benign shallow-water and the extreme abyssal environments suggests that triclads adapting to the latter faced primarily physiological and/or ecological adaptive challenges rather than developmental ones.
Topics: Humans; Animals; Phylogeny; Head; Platyhelminths; Water
PubMed: 38263880
DOI: 10.1098/rsbl.2023.0506 -
International Journal For Parasitology May 2006Voltage-gated calcium (Ca2+) channels provide the pathway for Ca2+ influxes that underlie Ca2+ -dependent responses in muscles, nerves and other excitable cells. They... (Review)
Review
Voltage-gated calcium (Ca2+) channels provide the pathway for Ca2+ influxes that underlie Ca2+ -dependent responses in muscles, nerves and other excitable cells. They are also targets of a wide variety of drugs and toxins. Ca2+ channels are multisubunit protein complexes consisting of a pore-forming alpha(1) subunit and other modulatory subunits, including the beta subunit. Here, we review the structure and function of schistosome Ca2+ channel subunits, with particular emphasis on variant Ca2+ channel beta subunits (Ca(v)betavar) found in these parasites. In particular, we examine the role these beta subunits may play in the action of praziquantel, the current drug of choice against schistosomiasis. We also present evidence that Ca(v)betavar homologs are found in other praziquantel-sensitive platyhelminths such as the pork tapeworm, Taenia solium, and that these variant beta subunits may thus represent a platyhelminth-specific gene family.
Topics: Amino Acid Sequence; Animals; Anthelmintics; Calcium Channels; Ion Channel Gating; Molecular Sequence Data; Platyhelminths; Praziquantel; Sequence Alignment
PubMed: 16545816
DOI: 10.1016/j.ijpara.2006.02.002 -
Parasitology Sep 2012During platyhelminth infection, a cocktail of proteins is released by the parasite to aid invasion, initiate feeding, facilitate adaptation and mediate modulation of the... (Review)
Review
During platyhelminth infection, a cocktail of proteins is released by the parasite to aid invasion, initiate feeding, facilitate adaptation and mediate modulation of the host immune response. Included amongst these proteins is the Venom Allergen-Like (VAL) family, part of the larger sperm coating protein/Tpx-1/Ag5/PR-1/Sc7 (SCP/TAPS) superfamily. To explore the significance of this protein family during Platyhelminthes development and host interactions, we systematically summarize all published proteomic, genomic and immunological investigations of the VAL protein family to date. By conducting new genomic and transcriptomic interrogations to identify over 200 VAL proteins (228) from species in all 4 traditional taxonomic classes (Trematoda, Cestoda, Monogenea and Turbellaria), we further expand our knowledge related to platyhelminth VAL diversity across the phylum. Subsequent phylogenetic and tertiary structural analyses reveal several class-specific VAL features, which likely indicate a range of roles mediated by this protein family. Our comprehensive analysis of platyhelminth VALs represents a unifying synopsis for understanding diversity within this protein family and a firm context in which to initiate future functional characterization of these enigmatic members.
Topics: Animals; Genes, Helminth; Helminth Proteins; Phylogeny; Platyhelminths; Protein Structure, Tertiary; Species Specificity
PubMed: 22717097
DOI: 10.1017/S0031182012000704 -
Marine Drugs May 2022Non-parasitic flatworms are known to temporarily attach to the substrate by secreting a multicomponent bioadhesive to counteract water movements. However, to date, only...
Non-parasitic flatworms are known to temporarily attach to the substrate by secreting a multicomponent bioadhesive to counteract water movements. However, to date, only species of two higher-level flatworm taxa (Macrostomorpha and Proseriata) have been investigated for their adhesive proteins. Remarkably, the surface-binding protein is not conserved between flatworm taxa. In this study, we sequenced and assembled a draft genome, as well as a transcriptome, and generated a tail-specific positional RNA sequencing dataset of the polyclad . This led to the identification of 15 candidate genes potentially involved in temporary adhesion. Using in situ hybridisation and RNA interference, we determined their expression and function. Of these 15 genes, 4 are homologues of adhesion-related genes found in other flatworms. With this work, we provide two novel key components on the flatworm temporary adhesion system. First, we identified a Kringle-domain-containing protein (Tmed-krg1), which was expressed exclusively in the anchor cell. This in silico predicted membrane-bound Tmed-krg1 could potentially bind to the cohesive protein, and a knockdown led to a non-adhesive phenotype. Secondly, a secreted tyrosinase (Tmed-tyr1) was identified, which might crosslink the adhesive proteins. Overall, our findings will contribute to the future development of reversible synthetic glues with desirable properties for medical and industrial applications.
Topics: Animals; Platyhelminths; Proteins; RNA Interference; Sequence Analysis, RNA; Transcriptome
PubMed: 35736161
DOI: 10.3390/md20060359 -
PloS One 2021Since the first complete set of Platyhelminth nuclear receptors (NRs) from Schistosoma mansoni were identified a decade ago, more flatworm genome data is available to...
Since the first complete set of Platyhelminth nuclear receptors (NRs) from Schistosoma mansoni were identified a decade ago, more flatworm genome data is available to identify their NR complement and to analyze the evolutionary relationship of Platyhelminth NRs. NRs are important transcriptional modulators that regulate development, differentiation and reproduction of animals. In this study, NRs are identified in genome databases of thirty-three species including in all Platyhelminth classes (Rhabditophora, Monogenea, Cestoda and Trematoda). Phylogenetic analysis shows that NRs in Platyhelminths follow two different evolutionary lineages: 1) NRs in a free-living freshwater flatworm (Schmidtea mediterranea) and all parasitic flatworms share the same evolutionary lineage with extensive gene loss. 2) NRs in a free-living intertidal zone flatworm (Macrostomum lignano) follow a different evolutionary lineage with a feature of multiple gene duplication and gene divergence. The DNA binding domain (DBD) is the most conserved region in NRs which contains two C4-type zinc finger motifs. A novel zinc finger motif is identified in parasitic flatworm NRs: the second zinc finger of parasitic Platyhelminth HR96b possesses a CHC2 motif which is not found in NRs of all other animals studied to date. In this study, novel NRs (members of NR subfamily 3 and 6) are identified in flatworms, this result demonstrates that members of all six classical NR subfamilies are present in the Platyhelminth phylum. NR gene duplication, loss and divergence in Platyhelminths are analyzed along with the evolutionary relationship of Platyhelminth NRs.
Topics: Animals; Evolution, Molecular; Gene Duplication; Phylogeny; Platyhelminths; Receptors, Cytoplasmic and Nuclear; Zinc Fingers
PubMed: 34388160
DOI: 10.1371/journal.pone.0250750 -
Parasitology Sep 2022The phylum Platyhelminthes shares a unique population of undifferentiated cells responsible for the proliferation capacity needed for cell renewal, growth, tissue repair...
The phylum Platyhelminthes shares a unique population of undifferentiated cells responsible for the proliferation capacity needed for cell renewal, growth, tissue repair and regeneration. These cells have been extensively studied in free-living flatworms, whereas in cestodes the presence of a set of undifferentiated cells, known as germinative cells, has been demonstrated in classical morphology studies, but poorly characterized with molecular biology approaches. Furthermore, several genes have been identified as neoblast markers in free-living flatworms that deserve study in cestode models. Here, different cell types of the model cestode were characterized, identifying differentiated and germinative cells. Muscle cells, tegumental cells, calcareous corpuscle precursor cells and excretory system cells were identified, all of which are non-proliferative, differentiated cell types. Besides those, germinative cells were identified as a population of small cells with proliferative capacity . Primary cell culture experiments in Dulbecco's Modified Eagle Medium (DMEM), hydatid fluid and hepatocyte conditioned media in non-reductive or reductive conditions confirmed that the germinative cells were the only ones with proliferative capacity. Since several genes have been identified as markers of undifferentiated neoblast cells in free-living flatworms, the expression of and genes was analysed by qPCR and hybridization, showing that the expression of these genes was stronger in germinative cells but not restricted to this cell type. This study provides the first tools to analyse and further characterise undifferentiated cells in a model cestode.
Topics: Animals; Cell Proliferation; Cestoda; Cestode Infections; Culture Media, Conditioned; Mesocestoides; Platyhelminths
PubMed: 35787303
DOI: 10.1017/S0031182022000956 -
Scientific Reports Feb 2018Free-living flatworms, such as the planarian Schmidtea mediterranea, are extensively used as model organisms to study stem cells and regeneration. The majority of...
Free-living flatworms, such as the planarian Schmidtea mediterranea, are extensively used as model organisms to study stem cells and regeneration. The majority of flatworm studies so far focused on broadly conserved genes. However, investigating what makes these animals different is equally informative for understanding its biology and might have biomedical value. We re-analyzed the neoblast and germline transcriptional signatures of the flatworm M. lignano using an improved transcriptome assembly and show that germline-enriched genes have a high fraction of flatworm-specific genes. We further identified the Mlig-sperm1 gene as a member of a novel gene family conserved only in free-living flatworms and essential for producing healthy spermatozoa. In addition, we established a whole-animal electron microscopy atlas (nanotomy) to visualize the ultrastructure of the testes in wild type worms, but also as a reference platform for different ultrastructural studies in M. lignano. This work demonstrates that investigation of flatworm-specific genes is crucial for understanding flatworm biology and establishes a basis for such future research in M. lignano.
Topics: Animals; Germ Cells; POU Domain Factors; Platyhelminths; Regeneration; Reproduction; Species Specificity; Stem Cells; Transcriptome
PubMed: 29453392
DOI: 10.1038/s41598-018-21107-4