-
Marine Drugs Dec 2022Tetrodotoxin (TTX) is a potent marine neurotoxin that occurs in several Australian phyla, including pufferfish, toadfish, gobies, and the blue-ringed octopus. These...
Tetrodotoxin (TTX) is a potent marine neurotoxin that occurs in several Australian phyla, including pufferfish, toadfish, gobies, and the blue-ringed octopus. These animals are partially immune, and TTX is known to bioaccumulate and subject to trophic transfer. As such, it could be more ubiquitously distributed in animals than is currently known. Flatworms of the order Polycladida are commonly occurring invertebrates in intertidal ecosystems and are especially diverse in Australian waters. While TTX has been identified in polyclads from Japan and New Zealand, Australian species have yet to be tested. In this study, several eastern Australian polyclad flatworm species from the suborders Cotylea and Acotylea were tested for TTX and analogs by HILIC-HRMS to understand the distribution of this toxin within these suborders. Herein, we report the detection of TTX and some known analogs in polyclad species, one of which is a pest to shellfish aquaculture. We also report, for the first time, the application of MALDI mass spectrometry imaging utilized to map TTX spatially within the intestinal system of polyclads. The identification of TTX and its analogs in Australian flatworms illustrates a broader range of toxic flatworms and highlights that analogs are important to consider when studying the distributions of toxins in animals.
Topics: Animals; Tetrodotoxin; Ecosystem; Australia; Platyhelminths; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 36547935
DOI: 10.3390/md20120788 -
The International Journal of... 2014Animals differ markedly in their ability to regenerate, yet still little is known about how regeneration evolves. In recent years, important advances have been made in... (Review)
Review
Animals differ markedly in their ability to regenerate, yet still little is known about how regeneration evolves. In recent years, important advances have been made in our understanding of animal phylogeny and these provide new insights into the phylogenetic distribution of regeneration. The developmental basis of regeneration is also being investigated in an increasing number of groups, allowing commonalities and differences across groups to become evident. Here, we focus on regeneration in the Spiralia, a group that includes several champions of animal regeneration, as well as many groups with more limited abilities. We review the phylogenetic distribution and developmental processes of regeneration in four major spiralian groups: annelids, nemerteans, platyhelminths, and molluscs. Although comparative data are still limited, this review highlights phylogenetic and developmental patterns that are emerging regarding regeneration in spiralians and identifies important avenues for future research.
Topics: Animals; Annelida; Biological Evolution; Mollusca; Phylogeny; Platyhelminths; Regeneration
PubMed: 25690976
DOI: 10.1387/ijdb.140142ab -
Integrative and Comparative Biology Aug 2015Predatory flatworms belonging to the taxon Kalyptorhynchia are characterized by an anterior muscular proboscis that they use to seize prey. In many cases, the proboscis... (Review)
Review
Predatory flatworms belonging to the taxon Kalyptorhynchia are characterized by an anterior muscular proboscis that they use to seize prey. In many cases, the proboscis is armed with hooks, derived either from the extracellular matrix that surrounds the muscles or from intracellular deposits in the epithelium covering the proboscis. Glands associated with the proboscis reportedly are venomous; however, there are few direct tests of this hypothesis. This article reviews the structure and current knowledge of the function of the proboscis in the Kalyptorhynchia, points to areas in which the current understanding of phylogenetic relationships within this taxon is incongruent with our hypothesis of how the proboscis evolved, and addresses areas in need of further research, especially as regards functional morphology and biomechanics.
Topics: Animals; Biological Evolution; Biomechanical Phenomena; Phylogeny; Platyhelminths; Predatory Behavior
PubMed: 26002347
DOI: 10.1093/icb/icv056 -
The FEBS Journal Aug 2013MicroRNAs (miRNAs) are a subtype of small regulatory RNAs that are involved in numerous biological processes through small RNA-induced silencing networks. In an attempt... (Comparative Study)
Comparative Study
MicroRNAs (miRNAs) are a subtype of small regulatory RNAs that are involved in numerous biological processes through small RNA-induced silencing networks. In an attempt to explore the phylogeny of miRNAs across five platyhelminths, we integrated annotated miRNAs and their full genomes. We identified conserved miRNA clusters and, in particular, miR-71/2 was conserved from planarian to parasitic flatworms and was expanded in free-living Schmidtea mediterranea. Analysis of 22 miRNA loci provided compelling evidence that most known miRNAs are conserved across platyhelminths. Meanwhile, we also observed alterations of known protein-coding genes flanking miRNA(s), such as transcriptional direction conversion and locus relocation, in around ~ 41% of 22 known miRNA loci. Compared with Echinococcus multilocularis, the majority of these events occurred in evolution-distant Hymenolepis microstoma, Schistosoma japonicum or/and S. mediterranea. These results imply rearrangement events occurred near the known miRNA loci.
Topics: 3' Flanking Region; 5' Flanking Region; Animals; Base Sequence; Conserved Sequence; DNA, Helminth; Databases, Nucleic Acid; Echinococcus granulosus; Echinococcus multilocularis; Gene Rearrangement; Genetic Loci; MicroRNAs; Multigene Family; Phylogeny; Planarians; Platyhelminths; RNA, Helminth; Schistosoma japonicum; Sequence Alignment
PubMed: 23777576
DOI: 10.1111/febs.12395 -
Biology Letters Sep 2019Understanding biological diversity is crucial for ecological and evolutionary studies. Even though a great part of animal diversity has already been documented, both...
Understanding biological diversity is crucial for ecological and evolutionary studies. Even though a great part of animal diversity has already been documented, both morphological surveys and metabarcoding analyses have previously shown that some animal groups, such as Platyhelminthes, may harbour hidden diversity. To better understand the molecular diversity of Platyhelminthes, one of the most diverse and biomedically important animal phyla, we here combined data from six marine and two freshwater metabarcoding expeditions that cover a broad variety of aquatic habitats and analysed the data by phylogenetic placement. Our results show that a great part of the hidden diversity is located in early-branching clades such as Catenulida and Macrostomorpha, as well as in late-diverging clades such as Proseriata and Rhabdocoela. We also report the first freshwater record of Gnosonesimida, a group previously thought to be exclusively marine. Finally, we identified two putative novel freshwater Platyhelminthes clades that branch between well-defined orders of the phylum. Thus, our analyses of several environmental datasets confirm that a large part of the diversity of Platyhelminthes remains undiscovered, point to groups with more potential novel species and identify freshwater environments as potential reservoirs for novel species of flatworms.
Topics: Animals; Biodiversity; Biological Evolution; Fresh Water; Phylogeny; Platyhelminths
PubMed: 31506037
DOI: 10.1098/rsbl.2019.0182 -
Genes Aug 2022The capsalid monogeneans are important pathogens that generally infect marine fishes and have a substantial impact on fish welfare in aquaculture systems worldwide....
The capsalid monogeneans are important pathogens that generally infect marine fishes and have a substantial impact on fish welfare in aquaculture systems worldwide. However, the current mitogenome information on capsalids has received little attention, limiting the understanding of their evolution and phylogenetic relationships with other monogeneans. This paper reports the complete mitochondrial genomes of and for the first time, which we obtained using a next-generation sequencing method. The mitogenomes of and are 13,265 and 13,984 bp in length, respectively. Both species contain the typical 12 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region. The genome compositions show a moderate A+T bias (66.5% and 63.9% for and , respectively) and exhibit a negative AT skew but a positive GC skew in both species. One gene block rearrangement was found in in comparison with other capsalid species. Instead of being basal to the Gyrodactylidea and Dactylogyridea or being clustered with Dactylogyridea, all species of Capsalidea are grouped into a monophyletic clade. Our results clarify the gene rearrangement process and evolutionary status of Capsalidae and lay a foundation for further phylogenetic studies of monogeneans.
Topics: Animals; Fishes; Genome, Mitochondrial; Phylogeny; Platyhelminths; RNA, Transfer; Trematoda
PubMed: 36011287
DOI: 10.3390/genes13081376 -
ELife Sep 2013Researchers have identified two genes-follistatin and activin-as having an important role in the ability of certain flatworms to identify wounds that require the...
Researchers have identified two genes-follistatin and activin-as having an important role in the ability of certain flatworms to identify wounds that require the production of new tissue.
Topics: Activins; Animals; Follistatin; Platyhelminths; Regeneration
PubMed: 24040510
DOI: 10.7554/eLife.00533 -
Current Biology : CB May 2015The interrelationships of the flatworms (phylum Platyhelminthes) are poorly resolved despite decades of morphological and molecular phylogenetic studies. The...
The interrelationships of the flatworms (phylum Platyhelminthes) are poorly resolved despite decades of morphological and molecular phylogenetic studies. The earliest-branching clades (Catenulida, Macrostomorpha, and Polycladida) share spiral cleavage and entolecithal eggs with other lophotrochozoans. Lecithoepitheliata have primitive spiral cleavage but derived ectolecithal eggs. Other orders (Rhabdocoela, Proseriata, Tricladida and relatives, and Bothrioplanida) all have derived ectolecithal eggs but have uncertain affinities to one another. The orders of parasitic Neodermata emerge from an uncertain position from within these ectolecithal classes. To tackle these problems, we have sequenced transcriptomes from 18 flatworms and 5 other metazoan groups. The addition of published data produces an alignment of >107,000 amino acids with less than 28% missing data from 27 flatworm taxa in 11 orders covering all major clades. Our phylogenetic analyses show that Platyhelminthes consist of the two clades Catenulida and Rhabditophora. Within Rhabditophora, we show the earliest-emerging branch is Macrostomorpha, not Polycladida. We show Lecithoepitheliata are not members of Neoophora but are sister group of Polycladida, implying independent origins of the ectolecithal eggs found in Lecithoepitheliata and Neoophora. We resolve Rhabdocoela as the most basally branching euneoophoran taxon. Tricladida, Bothrioplanida, and Neodermata constitute a group that appears to have lost both spiral cleavage and centrosomes. We identify Bothrioplanida as the long-sought closest free-living sister group of the parasitic Neodermata. Among parasitic orders, we show that Cestoda are closer to Trematoda than to Monogenea, rejecting the concept of the Cercomeromorpha. Our results have important implications for understanding the evolution of this major phylum.
Topics: Animals; Biological Evolution; Centromere; Female; Gene Expression Profiling; Male; Ovum; Phylogeny; Planarians; Platyhelminths; Spermatozoa; Terminology as Topic
PubMed: 25866392
DOI: 10.1016/j.cub.2015.03.034 -
BMC Genomics Jul 2020The genus Macrostomum consists of small free-living flatworms and contains Macrostomum lignano, which has been used in investigations of ageing, stem cell biology,...
BACKGROUND
The genus Macrostomum consists of small free-living flatworms and contains Macrostomum lignano, which has been used in investigations of ageing, stem cell biology, bioadhesion, karyology, and sexual selection in hermaphrodites. Two types of mating behaviour occur within this genus. Some species, including M. lignano, mate via reciprocal copulation, where, in a single mating, both partners insert their male copulatory organ into the female storage organ and simultaneously donate and receive sperm. Other species mate via hypodermic insemination, where worms use a needle-like copulatory organ to inject sperm into the tissue of the partner. These contrasting mating behaviours are associated with striking differences in sperm and copulatory organ morphology. Here we expand the genomic resources within the genus to representatives of both behaviour types and investigate whether genes vary in their rate of evolution depending on their putative function.
RESULTS
We present de novo assembled transcriptomes of three Macrostomum species, namely M. hystrix, a close relative of M. lignano that mates via hypodermic insemination, M. spirale, a more distantly related species that mates via reciprocal copulation, and finally M. pusillum, which represents a clade that is only distantly related to the other three species and also mates via hypodermic insemination. We infer 23,764 sets of homologous genes and annotate them using experimental evidence from M. lignano. Across the genus, we identify 521 gene families with conserved patterns of differential expression between juvenile vs. adult worms and 185 gene families with a putative expression in the testes that are restricted to the two reciprocally mating species. Further, we show that homologs of putative reproduction-related genes have a higher protein divergence across the four species than genes lacking such annotations and that they are more difficult to identify across the four species, indicating that these genes evolve more rapidly, while genes involved in neoblast function are more conserved.
CONCLUSIONS
This study improves the genus Macrostomum as a model system, by providing resources for the targeted investigation of gene function in a broad range of species. And we, for the first time, show that reproduction-related genes evolve at an accelerated rate in flatworms.
Topics: Animals; Evolution, Molecular; Genes, Helminth; Helminth Proteins; In Situ Hybridization; Phylogeny; Platyhelminths; RNA-Seq; Reproduction; Transcriptome
PubMed: 32631219
DOI: 10.1186/s12864-020-06862-x -
Genetics Jul 2021Regeneration-capable flatworms are informative research models to study the mechanisms of stem cell regulation, regeneration, and tissue patterning. The free-living...
Regeneration-capable flatworms are informative research models to study the mechanisms of stem cell regulation, regeneration, and tissue patterning. The free-living flatworm Macrostomum lignano is currently the only flatworm where stable transgenesis is available, and as such it offers a powerful experimental platform to address questions that were previously difficult to answer. The published transgenesis approach relies on random integration of DNA constructs into the genome. Despite its efficiency, there is room and need for further improvement and diversification of transgenesis methods in M. lignano. Transposon-mediated transgenesis is an alternative approach, enabling easy mapping of the integration sites and the possibility of insertional mutagenesis studies. Here, we report for the first time that transposon-mediated transgenesis using piggyBac can be performed in M. lignano to create stable transgenic lines with single-copy transgene insertions.
Topics: Animals; DNA Transposable Elements; Gene Transfer Techniques; Platyhelminths; Transgenes
PubMed: 33999134
DOI: 10.1093/genetics/iyab076