-
PloS One 2015Mitochondrial genomes (mitogenomes) are useful and relatively accessible sources of molecular data to explore and understand the evolutionary history and relationships...
Mitochondrial genomes (mitogenomes) are useful and relatively accessible sources of molecular data to explore and understand the evolutionary history and relationships of eukaryotic organisms across diverse taxonomic levels. The availability of complete mitogenomes from Platyhelminthes is limited; of the 40 or so published most are from parasitic flatworms (Neodermata). Here, we present the mitogenomes of two free-living flatworms (Tricladida): the complete genome of the freshwater species Crenobia alpina (Planariidae) and a nearly complete genome of the land planarian Obama sp. (Geoplanidae). Moreover, we have reanotated the published mitogenome of the species Dugesia japonica (Dugesiidae). This contribution almost doubles the total number of mtDNAs published for Tricladida, a species-rich group including model organisms and economically important invasive species. We took the opportunity to conduct comparative mitogenomic analyses between available free-living and selected parasitic flatworms in order to gain insights into the putative effect of life cycle on nucleotide composition through mutation and natural selection. Unexpectedly, we did not find any molecular hallmark of a selective relaxation in mitogenomes of parasitic flatworms; on the contrary, three out of the four studied free-living triclad mitogenomes exhibit higher A+T content and selective relaxation levels. Additionally, we provide new and valuable molecular data to develop markers for future phylogenetic studies on planariids and geoplanids.
Topics: Animals; Base Sequence; Evolution, Molecular; GC Rich Sequence; Genome, Helminth; Genome, Mitochondrial; Molecular Sequence Data; Mutation; Phylogeny; Platyhelminths; Selection, Genetic; Virulence
PubMed: 25793530
DOI: 10.1371/journal.pone.0120081 -
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 -
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 -
Molecular & Cellular Proteomics : MCP 2021The extracellular matrix (ECM) is a three-dimensional network of macromolecules that provides a microenvironment capable of supporting and regulating cell functions....
The extracellular matrix (ECM) is a three-dimensional network of macromolecules that provides a microenvironment capable of supporting and regulating cell functions. However, only a few research organisms are available for the systematic dissection of the composition and functions of the ECM, particularly during regeneration. We utilized the free-living flatworm Schmidtea mediterranea to develop an integrative approach consisting of decellularization, proteomics, and RNAi to characterize and investigate ECM functions during tissue homeostasis and regeneration. ECM-enriched samples were isolated from planarians, and their proteomes were characterized by LC-MS/MS. The functions of identified ECM components were interrogated using RNA interference. Using this approach, we found that heparan sulfate proteoglycan is essential for tissue regeneration. Our strategy provides an experimental approach for identifying both known and novel ECM components involved in regeneration.
Topics: Animals; Decellularized Extracellular Matrix; Helminth Proteins; Heparan Sulfate Proteoglycans; Homeostasis; Planarians; Proteome; RNA Interference; Regeneration
PubMed: 34416386
DOI: 10.1016/j.mcpro.2021.100137 -
The American Journal of Tropical... Jul 2020Analyses of the population genetic structure of schistosomes under the "Schistosomiasis Consortium for Operational Research and Evaluation" (SCORE) contrasting treatment... (Review)
Review
Analyses of the population genetic structure of schistosomes under the "Schistosomiasis Consortium for Operational Research and Evaluation" (SCORE) contrasting treatment pressure scenarios in Tanzania, Niger, and Zanzibar were performed to provide supplementary critical information with which to evaluate the impact of these large-scale control activities and guide how activities could be adjusted. We predicted that population genetic analyses would reveal information on a range of important parameters including, but not exclusive to, recruitment and transmission of genotypes, occurrence of hybridization events, differences in reproductive mode, and degrees of inbreeding, and hence, the evolutionary potential, and responses of parasite populations under contrasting treatment pressures. Key findings revealed that naturally high levels of gene flow and mixing of the parasite populations between neighboring sites were likely to dilute any effects imposed by the SCORE treatment arms. Furthermore, significant inherent differences in parasite fecundity were observed, independent of current treatment arm, but potentially of major impact in terms of maintaining high levels of ongoing transmission in persistent "biological hotspot" sites. Within Niger, naturally occurring viable hybrids were found to be abundant, often occurring in significantly higher proportions than that of single-species infections. By examining parasite population genetic structures across hosts, treatment regimens, and the spatial landscape, our results to date illustrate key transmission processes over and above that which could be achieved through standard parasitological monitoring of prevalence and intensity alone, as well as adding to our understanding of spp. life history strategies in general.
Topics: Africa South of the Sahara; Animals; Anthelmintics; Genetics, Population; Humans; Hybridization, Genetic; Life Cycle Stages; Mass Drug Administration; Prevalence; Schistosoma; Schistosoma haematobium; Schistosomiasis
PubMed: 32400355
DOI: 10.4269/ajtmh.19-0827 -
Journal of the American Veterinary... Sep 2023To raise veterinary awareness of a newly recognized parasitic threat to canine and human health, highlight the increasing availability of molecular parasitological...
OBJECTIVE
To raise veterinary awareness of a newly recognized parasitic threat to canine and human health, highlight the increasing availability of molecular parasitological diagnostics and the need to implement best practices of cestocidal use in high-risk dogs.
ANIMAL
A young Boxer dog with vomiting and bloody diarrhea, suspected diagnosis of inflammatory bowel disease.
CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES
Bloodwork revealed inflammation, dehydration, and protein loss, addressed with supportive therapy. Fecal culture revealed only Escherichia coli. On centrifugal flotation, tapeworm eggs (which could be Taenia or Echinococcus spp) and, unusually, adult cestodes of Echinococcus were observed. The referring veterinarian was contacted to initiate immediate treatment with a cestocide due to zoonotic potential. Diagnosis was confirmed with a coproPCR which has higher sensitivity for Echinococcus spp than fecal flotation alone. DNA was identical to an introduced European strain of E multilocularis currently emerging in dogs, people, and wildlife. Since dogs can also self-infect and develop hepatic alveolar echinococcosis (severe and often fatal), this was ruled out using serology and abdominal ultrasound.
TREATMENT AND OUTCOME
Following cestocidal treatment, fecal flotation and coproPCR were negative for eggs and DNA of E multilocularis; however, coccidia were detected and diarrhea resolved following treatment with sulfa-based antibiotics.
CLINICAL RELEVANCE
This dog was serendipitously diagnosed with E multilocularis, acquired through ingestion of a rodent intermediate host likely infected from foxes and coyotes. Therefore, as a dog at high risk of reexposure from eating rodents, regular (ideally monthly) treatment with a labeled cestocide is indicated going forward.
Topics: Echinococcus multilocularis; Animals; Dogs; Echinococcosis; Female; Dog Diseases
PubMed: 37179049
DOI: 10.2460/javma.23.02.0099 -
Parasitology Nov 2022is the aetiological agent of cysticercosis, a zoonosis that causes severe health and economic losses across Latin America, Africa and Asia. The most serious...
is the aetiological agent of cysticercosis, a zoonosis that causes severe health and economic losses across Latin America, Africa and Asia. The most serious manifestation of the disease is neurocysticercosis, which occurs when the larval stage (cysticercus) establishes in the central nervous system. Using as an experimental model organism for the study of cysticercosis, we aimed to identify the conditions necessary to allow parasite development at the short- and long terms. First, cysticerci were incubated for 15 days in different media and parasite densities. The number of buddings and cysticerci diameter were measured to evaluate asexual multiplication and parasite growth, respectively. Vitality was determined by trypan blue staining and morphology analysis. As a result, high cysticerci density and medium containing FBS and the excretion/secretion (E/S) products of feeder cells induced parasite survival, growth and multiplication. Then, the long-term (5 weeks) incubation of the parasites in co-culture with feeder cells was evaluated. Consequently, the mammalian cell lines induced a significant increase in total parasite volume while axenic cultures did not show any statistically significant change over time. In this study, the proper conditions to maintain are described for the first time in a simpler and more controlled setting other than experimental infections. In addition, it was shown that cysticerci growth, survival and asexual multiplication depend on a complex network of secreted factors from both parasite and host.
Topics: Animals; Humans; Mice; Cysticercus; Taenia; Taenia solium; Cysticercosis; Neurocysticercosis; Parasites; Mice, Inbred BALB C; Mammals
PubMed: 36165285
DOI: 10.1017/S0031182022001354 -
Proceedings of the National Academy of... Oct 2017Asexual freshwater planarians reproduce by tearing themselves into two pieces by a process called binary fission. The resulting head and tail pieces regenerate within...
Asexual freshwater planarians reproduce by tearing themselves into two pieces by a process called binary fission. The resulting head and tail pieces regenerate within about a week, forming two new worms. Understanding this process of ripping oneself into two parts poses a challenging biomechanical problem. Because planarians stop "doing it" at the slightest disturbance, this remained a centuries-old puzzle. We focus on fission and show that it proceeds in three stages: a local constriction ("waist formation"), pulsation-which increases waist longitudinal stresses-and transverse rupture. We developed a linear mechanical model with a planarian represented by a thin shell. The model fully captures the pulsation dynamics leading to rupture and reproduces empirical time scales and stresses. It asserts that fission execution is a mechanical process. Furthermore, we show that the location of waist formation, and thus fission, is determined by physical constraints. Together, our results demonstrate that where and how a planarian rips itself apart during asexual reproduction can be fully explained through biomechanics.
Topics: Animals; Fresh Water; Planarians; Regeneration; Reproduction, Asexual
PubMed: 28973880
DOI: 10.1073/pnas.1700762114 -
BMC Veterinary Research May 2021Platyhelminth infections of livestock can result in considerable economic losses. This study aims to evaluate the spatial frequency of cystic echinococcosis (CE),...
BACKGROUND
Platyhelminth infections of livestock can result in considerable economic losses. This study aims to evaluate the spatial frequency of cystic echinococcosis (CE), dicrocoeliasis, and fascioliasis in livestock slaughtered in Iran during the years 2015-2019 and estimate direct costs associated with organ condemnation due to these parasites.
METHODS
Abattoir data from 413 abattoirs representing all 31 Iranian provinces were collected from the Iran Veterinary Organization. Infection prevalence was calculated per year at the province level. The Local Moran's I statistic was performed to evaluate spatial autocorrelation of animals positive at slaughter for the years 2015-2019. Direct costs associated with condemned livers were calculated for each parasitic condition, with costs associated with condemned lungs also included for CE.
RESULTS
Overall prevalence values for the study timeframe were as follows: sheep and goat fascioliasis 1.56% (95% CI: 1.56-1.56%), cattle fascioliasis 3.86% (95% CI: 3.85-3.88%), sheep and goat dicrocoeliasis 4.63% (95% CI: 4.62-4.63%), cattle dicrocoeliasis 3.08% (95% CI: 3.07-3.09%), sheep and goat CE 5.32% (95% CI: 5.32-5.33%), and cattle CE 7.26% (95% CI: 7.24-7.28%). Northwest Iran had the highest prevalence of CE and fascioliasis. High infection areas for Dicrocoelium spp. included the provinces of Zanjan, Gilan, Qazvin, and Tehran, which are located in northern Iran. Direct economic losses for sheep and goat fascioliasis, dicrocoeliasis, and CE for the study period were US$13,842,759, US$41,771,377, and US$22,801,054, respectively. Direct economic losses for cattle fascioliasis, dicrocoeliasis, and CE for the study period were US$1,989,200, US$1,668,986, and US$2,656,568, respectively.
CONCLUSION
Our findings provide valuable data for future monitoring of these important parasitic diseases in Iranian livestock. Disease control strategies are required to reduce the economic and public health impact of these platyhelminths.
Topics: Abattoirs; Animals; Cattle; Cattle Diseases; Dicrocoeliasis; Dicrocoelium; Echinococcosis; Echinococcus; Fasciola; Fascioliasis; Goat Diseases; Goats; Iran; Livestock; Sheep; Sheep Diseases; Zoonoses
PubMed: 33952280
DOI: 10.1186/s12917-021-02888-9