A phylum of acoelomate, bilaterally symmetrical flatworms, without a definite anus. It includes three classes: Cestoda, Turbellaria, and Trematoda.
A class of free-living freshwater flatworms of North America.
A subclass of segmented worms comprising the tapeworms.
A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.
A species of trematode blood flukes of the family Schistosomatidae. It is common in the Nile delta. The intermediate host is the planorbid snail. This parasite causes schistosomiasis mansoni and intestinal bilharziasis.
Encysted cercaria which house the intermediate stages of trematode parasites in tissues of an intermediate host.
Proteins found in any species of helminth.
Family of MITES in the superfamily Trombiculoidea, suborder Prostigmata, which attack humans and other vertebrates, causing DERMATITIS and severe allergic reactions. Chiggers, red bugs, and harvest mites commonly refer to the larval stage of Trombiculid mites, the only parasitic stage of the mite's life cycle.
An order of small, wingless parasitic insects, commonly known as lice. The suborders include ANOPLURA (sucking lice); AMBLYCERA; ISCHNOCERA; and Rhynchophthirina (elephant and warthog lice).
A family of freshwater fish of the order ESOCIFORMES, comprising the pikes, inhabiting the waters of the Northern Hemisphere. There is one genus, Esox, with five species: northern pike, grass pickerel, chain pickerel, muskellunge, and Amur pike.
An order of CRUSTACEA that are parasitic on freshwater fish.
A large, subclass of arachnids comprising the MITES and TICKS, including parasites of plants, animals, and humans, as well as several important disease vectors.
Any arthropod of the subclass ACARI except the TICKS. They are minute animals related to the spiders, usually having transparent or semitransparent bodies. They may be parasitic on humans and domestic animals, producing various irritations of the skin (MITE INFESTATIONS). Many mite species are important to human and veterinary medicine as both parasite and vector. Mites also infest plants.
A family of softbacked TICKS, in the subclass ACARI. Genera include ARGAS and ORNITHODOROS among others.
Schistosomiasis caused by Schistosoma mansoni. It is endemic in Africa, the Middle East, South America, and the Caribbean and affects mainly the bowel, spleen, and liver.
A genus of trematode flukes belonging to the family Schistosomatidae. There are over a dozen species. These parasites are found in man and other mammals. Snails are the intermediate hosts.
A genus of planorbid freshwater snails, species of which are intermediate hosts of Schistosoma mansoni.
A family of blood flukes of the class Trematoda which is found in animals and man. It Includes the genera Heterobilharzia, Schistosomatium, Schistosoma, Ornithobilharzia, Bilharziella, Trichobilharzia, Pseudobilharzia, and Austrobilharzia.
Infection with flukes (trematodes) of the genus SCHISTOSOMA. Three species produce the most frequent clinical diseases: SCHISTOSOMA HAEMATOBIUM (endemic in Africa and the Middle East), SCHISTOSOMA MANSONI (in Egypt, northern and southern Africa, some West Indies islands, northern 2/3 of South America), and SCHISTOSOMA JAPONICUM (in Japan, China, the Philippines, Celebes, Thailand, Laos). S. mansoni is often seen in Puerto Ricans living in the United States.
Marine, freshwater, or terrestrial mollusks of the class Gastropoda. Most have an enclosing spiral shell, and several genera harbor parasites pathogenic to man.
Invertebrate organisms that live on or in another organism (the host), and benefit at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.
The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.
Infections with bacteria of the genus STREPTOCOCCUS.
Infections or infestations with parasitic organisms. The infestation may be experimental or veterinary.
Proteins found in any species of protozoan.
Measure of the number of the PARASITES present in a host organism.
The interdisciplinary science that studies evolutionary biology, including the origin and evolution of the major elements required for life, their processing in the interstellar medium and in protostellar systems. This field also includes the study of chemical evolution and the subsequent interactions between evolving biota and planetary evolution as well as the field of biology that deals with the study of extraterrestrial life.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
Nonparasitic free-living flatworms of the class Turbellaria. The most common genera are Dugesia, formerly Planaria, which lives in water, and Bipalium, which lives on land. Geoplana occurs in South America and California.
Class of parasitic flukes consisting of three subclasses, Monogenea, Aspidogastrea, and Digenea. The digenetic trematodes are the only ones found in man. They are endoparasites and require two hosts to complete their life cycle.
Properties and processes of the DIGESTIVE SYSTEM as a whole or of any of its parts.
Infestations by PARASITES which live on, or burrow into, the surface of their host's EPIDERMIS. Most ectoparasites are ARTHROPODS.
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
Infestation of animals with parasitic worms of the helminth class. The infestation may be experimental or veterinary.
A genus of mosquitoes (CULICIDAE) that are known vectors of MALARIA.
A species of mosquito in the genus Anopheles and the principle vector of MALARIA in Africa.
Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.
Substances causing insects to turn away from them or reject them as food.
Proteins, usually projecting from the cilia of olfactory receptor neurons, that specifically bind odorant molecules and trigger responses in the neurons. The large number of different odorant receptors appears to arise from several gene families or subfamilies rather than from DNA rearrangement.
A protozoan disease caused in humans by four species of the PLASMODIUM genus: PLASMODIUM FALCIPARUM; PLASMODIUM VIVAX; PLASMODIUM OVALE; and PLASMODIUM MALARIAE; and transmitted by the bite of an infected female mosquito of the genus ANOPHELES. Malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands. It is characterized by extreme exhaustion associated with paroxysms of high FEVER; SWEATING; shaking CHILLS; and ANEMIA. Malaria in ANIMALS is caused by other species of plasmodia.
A plant genus of the family BORAGINACEAE.

Acoel flatworms: earliest extant bilaterian Metazoans, not members of Platyhelminthes. (1/140)

Because of their simple organization the Acoela have been considered to be either primitive bilaterians or descendants of coelomates through secondary loss of derived features. Sequence data of 18S ribosomal DNA genes from non-fast evolving species of acoels and other metazoans reveal that this group does not belong to the Platyhelminthes but represents the extant members of the earliest divergent Bilateria, an interpretation that is supported by recent studies on the embryonic cleavage pattern and nervous system of acoels. This study has implications for understanding the evolution of major body plans, and for perceptions of the Cambrian evolutionary explosion.  (+info)

Infections by helminth parasites in "puyenes", Galaxias maculatus (Galaxiidae, Salmoniformes), from Southern Argentina with special reference to Tylodelphys barilochensis (Digenea, Platyhelminthes). (2/140)

The occurrence of Tylodelphys barilochensis, Acanthostomoides apophalliformis, Contracaecum sp. and Camallanus corderoi infecting Galaxias maculatus ("puyenes") was quantified for the first time in Lake Nahuel Huapi, southern Argentina. T. barilochensis was recorded in this lake for the first time. The role of G. maculatus population in transmission of parasites to the salmonids is more important for Contracaecum sp. (prevalence 14-34%) and A. apophalliformis (prevalence 30-54%) than for C. corderoi (prevalence 6-8%). The absence of Diphyllobothrium spp. in samples shows that the G. maculatus population does not play any role in the life cycles of these important zoonotic parasites. The sex of the host had no effect on T. barilochensis abundance. Statistical differences in T. barilochensis abundance between "puyenes" of the same size class between sampling stations and positive correlation between prevalence of infected snails and T. barilochensis abundance in fish suggest that different stocks have been sampled. Factors influencing T. barilochensis abundance are discussed.  (+info)

First report of Temnocephala brevicornis Monticelli 1889 (Temnocephalidae: platyhelminthes) in Argentina. (3/140)

Temnocephala brevicornis Monticelli 1889, ectosymbiont of Hydromedusa tectifera Cope 1869, is reported for the first time for Argentina. Numerous temnocephalans from Arroyo Villoldo in the locality of Magdalena, Buenos Aires, Argentina were stained in toto to be studied. This commensal species in turtles was originally cited in association with Hydromedusa maximiliani (Mikan) and Hydraspis radiolata Mikan in Brazil. Afterwards, it was found on other fresh water turtle species in Brazil and Uruguay.  (+info)

Treatment of Microcotyle sebastis (Monogenea: Polyopisthocotylea) infestation with praziquantel in an experimental cage simulating commercial rockfish Sebastes schlegeli culture conditions. (4/140)

The antiparasitic efficacy of praziquantel against the blood-sucking polyopisthocotylean Microcotyle sebastis was tested in an experimental cage simulating commercial rockfish-culture conditions. Juvenile rockfish Sebastes schlegeli were separated into 4 pilot net-pens, and the fish in the groups were either fed a control diet (Group C), fed a praziquantel-adsorbed diet (Group F), bathed in 100 ppm praziquantel for 4 min (Group B), or bathed in 100 ppm praziquantel for 4 min and then fed a praziquantel-adsorbed diet (Group BF). The results of the present study indicate that feeding a praziquantel-adsorbed diet significantly reduces the abundance of M. sebastis infestation, and bathing in 100 ppm praziquantel for 4 min is effective for controlling M. sebastis infestation in practical rockfish culture systems.  (+info)

The evolution of the serotonergic nervous system. (5/140)

The pattern of development of the serotonergic nervous system is described from the larvae of ctenophores, platyhelminths, nemerteans, entoprocts, ectoprocts (bryozoans), molluscs, polychaetes, brachiopods, phoronids, echinoderms, enteropneusts and lampreys. The larval brain (apical ganglion) of spiralian protostomes (except nermerteans) generally has three serotonergic neurons and the lateral pair always innervates the ciliary band of the prototroch. In contrast, brachiopods, phoronids, echinoderms and enteropneusts have numerous serotonergic neurons in the apical ganglion from which the ciliary band is innervated. This pattern of development is much like the pattern seen in lamprey embryos and larvae, which leads the author to conclude that the serotonergic raphe system found in vertebrates originated in the larval brain of deuterostome invertebrates. Further, the neural tube of chordates appears to be derived, at least in part, from the ciliary band of deuterostome invertebrate larvae. The evidence shows no sign of a shift in the dorsal ventral orientation within the line leading to the chordates.  (+info)

Elongation factor 1-alpha sequences do not support an early divergence of the Acoela. (6/140)

The phylogenetic position of the Acoela is a key problem in the understanding of metazoan evolution. Recent studies based on 18S ribosomal DNA (rDNA) sequences have placed the Acoela in an extremely basal position as the sister group to all other extant triploblastic animals, suggesting that the phylum Platyhelminthes is polyphyletic. In order to test the results obtained with 18S rDNA, we sequenced elongation factor 1-alpha (EF1a) for the acoel Convoluta roscoffensis and five species of Turbellaria (two polyclads, Leptoplana tremellaris, and Prostheceraeus vittatus, and three triclads, Crenobia alpina, Schmidtea polychroa, and Girardia tigrina). Phylogenetic analyses of EF1a sequences show that the acoel sequences branch within the Platyhelminthes, in opposition to the 18S rDNA data. Moreover, comparison of the central variable region of EF1a shows similar sequence signatures between C. roscoffensis and the three triclad species. Although EF1a sequences fail to prove the monophyly of the phylum Platyhelminthes, they do not confirm the early divergence of the Acoela.  (+info)

Myzostomida: a link between trochozoans and flatworms? (7/140)

Myzostomids are obligate symbiotic invertebrates associated with echinoderms with a fossil record that extends to the Ordovician period. Due to their long history as host-specific symbionts, myzostomids have acquired a unique anatomy that obscures their phylogenetic affinities to other metazoans: they are incompletely segmented, parenchymous, acoelomate organisms with chaetae and a trochophore larva. Today, they are most often classified within annelids either as an aberrant family of polychaetes or as a separate class. We inferred the phylogenetic position of the Myzostomida by analysing the DNA sequences of two slowly evolving nuclear genes: the small subunit ribosomal RNA and elongation factor-1alpha. All our analyses congruently indicated that myzostomids are not annelids but suggested instead that they are more closely related to flatworms than to any trochozoan taxon. These results, together with recent analyses of the myzostomidan ultrastructure, have significant implications for understanding the evolution of metazoan body plans, as major characters (segmentation, coeloms, chaetae and trochophore larvae) might have been independently lost or gained in different animal phyla.  (+info)

K(+) currents in cultured neurones from a polyclad flatworm. (8/140)

Cells from the brain of the polyclad flatworm Notoplana atomata were dispersed and maintained in primary culture for up to 3 weeks. Whole-cell patch-clamp of presumed neurones revealed outwardly directed K(+) currents that comprised, in varying proportions, a rapidly activating (time constant tau =0.94+/-0.79 ms; N=15) and inactivating ( tau =26.1+/-1.9 ms; N=22) current and a second current that also activated rapidly ( tau =1.1+/-0.2 ms; N=9) (means +/- s.e.m.) but did not inactivate within 100 ms. Both current types activated over similar voltage ranges. Activation and steady-state inactivation overlap and are markedly rightward-shifted compared with most Shaker-like currents (half-activation of 16.9+/-1. 9 mV, N=7, half-inactivation of -35.4+/-3.0 mV, N=5). Recovery from inactivation was rapid (50+/-2.5 ms at -90 mV). Both currents were unaffected by tetraethylammonium (25 mmol l(-1)), whereas 4-aminopyridine (10 mmol l(-1)) selectively blocked the inactivating current. The rapidly inactivating current, like cloned K(+) channels from cnidarians and certain cloned K(+) channels from molluscs and the Kv3 family of vertebrate channels, differed from most A-type K(+) currents reported to date. These findings suggest that K(+) currents in Notoplana atomata play novel roles in shaping excitability properties.  (+info)

Define phylum Platyhelminthes. phylum Platyhelminthes synonyms, phylum Platyhelminthes pronunciation, phylum Platyhelminthes translation, English dictionary definition of phylum Platyhelminthes. Noun 1. phylum Platyhelminthes - flatworms Platyhelminthes animal kingdom, Animalia, kingdom Animalia - taxonomic kingdom comprising all living or extinct...
In the two species for which data on myogenesis are available so far, F-actin is only present in the zonulae adhaerentes of the cell walls until 50% (Isodiametra pulchra) or 40% (Symsagittifera roscoffensis) of development between egg laying and hatching [27], present study. The signal in the zonulae adhaerentes decreases gradually with further development in I. pulchra [27]. Such a situation could not be observed in S. roscoffensis.. Slightly later, short isolated circular muscles appear in the embryo of Isodiametra pulchra, and four or five bands of primary circular muscles encircle the embryo just after 50% of development. The circular muscle bands increase to six to eight muscle bands, followed by single primary longitudinal fibres. These longitudinal fibres emerge independently of each other together with additional circular muscles [27]. In Symsagittifera roscoffensis, no such stage in which only circular muscles are present was found. However, we cannot fully exclude the existence of such ...
Symsagittifera roscoffensis is a plathelminth living in symbiosis with the green algae Tetraselmis convolutae. Host and symbiont are a model system for the study of endosymbiosis, so far mainly focused on their biochemical interactions. S. roscoffensis is well known for its positive phototaxis that is hypothesized to optimize the symbionts light perception for photosynthesis. In this study, we conducted a detailed analysis of phototaxis using light sources of different wavelength and brightness by videotracking. Furthermore, we compared the behavioral data with the electron transfer rate of the photosystem from cultured symbiotic cells. The symbiotic algae is adapted to low light conditions showing a positive electron transfer rate (ETR) already at a photosynthetically active radiation (PAR) of 0.112 µmol m−2 s−1 (mol photons per square meter and second), and S. roscoffensis showed a positive phototactic behaviour for light intensities up to 459.17 µmol m−2 s−1 which are not optimal ...
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There are around 29,000 described species in the phylum Platyhelminthes (Zhang 2011). Platyhelminths, or flatworms, include both free-living and parasitic species. The phylum Platyhelminthes is divided into two monophyletic clades, the Catenulida (with just around 100 known species; Larsson and Jondelius 2008) and the Rhabditophora, which includes nearly all known platyhelminths (Timothy et al. 2004; Willems et al. 2006; Larsson and Jondelius 2008).. The majority of flatworms are obligately parasitic, either flukes (members of the classes Trematoda and Monogenea, such as the Schistosoma trematodes that cause schistosomiasis) or tapeworms (members of the class Cestoda, such as the Beef Tapeworm) (Brusca and Brusca 2003). These obligately parasitic groups together form a monophyletic clade known as Neodermata. Many of these parasitic flatworms have complex life cycles involving multiple hosts. The non-parasitic flatworms, which until recently were usually placed together in a group known as ...
Free-living flatworms are also found in the marine environment. They are also called polyclads, which means any branches, referring to the highly branched guts radiating from their mouths. Scientifically, marine flatworms are placed in the class Turbellaria, and order Polycladida. As marine flatworms are usually very flat, they are very fragile and get torn easily. But been flat also allows them to slide into narrow cracks and crevices to seek prey and escape predation. Like other flatworms, they are mostly carnivorous, and usually feed on sessile organisms such as tunicates and bryozoans. Some may feed on motile organisms too, such as some worms and crustaceans, while others may scavenge. Only a few are herbivorous, feeding on algae. The mouth is on the underside, and may be located near the front end, in the middle or even near the rear end, depending on the species. Like the terrestrial flatworms, they have a pharynx for feeding ...
Phylum Platyhelminthes Habit and habitat: Members of this phylum are mainly ectoparasite or endoparasite of other organisms but a few species are free livi
Identifying Characteristics of the Phylum Platyhelminthes Acoelomate Exhibit bilateral symmetry Have a bilateral nervous system with cephalization at the head end. Some species exhibit eyespots sensitive to light Possess a Gastrovascular Cavity (GVC) and primitive organ systems for digestion and excretion Do not have a circulatory or respiratory system but do take in O2 through their body surface (integumentary exchange) Hermaphroditic : can reproduce sexually (do not self fertilize) or asexually by regeneration Are motile and utilize an undulation form of motion Found in marine, freshwater and damp terrestrial habitats
Background. To date, mitochondrial genomes of more than one hundred flatworms (Platyhelminthes) have been sequenced. They show a high degree of similarity and a strong taxonomic bias towards parasitic lineages. The mitochondrial gene atp8 has not been confidently annotated in any flatworm sequenced to date. However, sampling of free-living flatworm lineages is incomplete. We addressed this by sequencing the mitochondrial genomes of the two small-bodied (about 1 mm in length) free-living flatworms Stenostomum sthenum and Macrostomum lignano as the first representatives of the earliest branching flatworm taxa Catenulida and Macrostomorpha respectively.. Results. We have used high-throughput DNA and RNA sequence data and PCR to establish the mitochondrial genome sequences and gene orders of S. sthenum and M. lignano. The mitochondrial genome of S. sthenum is 16,944 bp long and includes a 1,884 bp long inverted repeat region containing the complete sequences of nad3, rrnS, and nine tRNA genes. The ...
This thesis focuses on phylogenetic and taxonomic studies of Catenulida (Platyhelminthes). Catenulida is a group of microscopic free-living worms mainly found in freshwater habitats. The Swedish catenulid fauna was previously virtually unknown. The taxonomy of Catenulida is difficult because of the paucity of good morphological characters, which makes species identification extremely difficult. Molecular phylogenies are inferred from DNA sequences. Based on two molecular markers, 18S rDNA and 28S rDNA, the phylogenetic position of Catenulida has now been well established as the sister group to the rest of the flatworms, Rhabditophora. Within Catenulida there is a basal split between two major clades: Retronectidae + Catenulidae and Stenostomidae. The hypothesis of the marine Retronectidae as the sister group of the limnic Catenulida is rejected. Four molecular markers, 18S rDNA, 28S rDNA, ITS-5.8S and CO1, are used as a backbone to infer phylogeny and to generate hypotheses about species ...
View Notes - PLATYHELMINTHS from MCB MCB2010 at Broward College. PLATYHELMINTHS (THE FLATWORMS) 8) When a human eats the crayfish that has not been sufficiently cooked, the metacercariae come out of
Hox genes are critical for patterning the bilaterian anterior-posterior axis. The evolution of their clustered genomic arrangement and ancestral function has been debated since their discovery. As acoels appear to represent the sister group to the remaining Bilateria (Nephrozoa), investigating Hox gene expression will provide an insight into the ancestral features of the Hox genes in metazoan evolution. We describe the expression of anterior, central and posterior class Hox genes and the ParaHox ortholog Cdx in the acoel Convolutriloba longifissura. Expression of all three Hox genes begins contemporaneously after gastrulation and then resolves into staggered domains along the anterior-posterior axis, suggesting that the spatial coordination of Hox gene expression was present in the bilaterian ancestor. After early surface ectodermal expression, the anterior and central class genes are expressed in small domains of putative neural precursor cells co-expressing ClSoxB1, suggesting an evolutionary early
TY - JOUR. T1 - Contributions to the phylogeny of platyhelminthes based on partial sequencing of 18S ribosomal DNA. AU - Rohde, Klaus. AU - Hefford, Chris. AU - Ellis, John T.. AU - Baverstock, Peter R.. AU - Johnson, Alan M.. AU - Watson, Nikki A.. AU - Dittmann, Sabine. PY - 1993/9. Y1 - 1993/9. N2 - Partial sequencing of the 18S ribosomal DNA gene of one nemertean and 13 free-living and parasitic Platyhelminthes (556 nucleotides), and of one nemertean and 20 Platyhelminthes (556 nucleotides) was used to test several hypotheses concerning the phylogenetic relationships of Platyhelminthes. The following conclusions were reached: the Neodermata is monophyletic; Trematoda (Aspidogastrea and Digenea) is monophyletic, although a sister group relationship of the Aspidogastrea and all other Neodermata cannot be definitely ruled out; the Cestoda comprising the Eucestoda, Amphilinidea and Gyrocotylidea is monophyletic; it is unresolved whether the Monogenea is paraphyletic; neither Gyrocotylidea and ...
Because of their simple organization the Acoela have been considered to be either primitive bilaterians or descendants of coelomates through secondary loss of derived features. Sequence data of 18S ribosomal DNA genes from non-fast evolving species of acoels and other metazoans reveal that this group does not belong to the Platyhelminthes but represents the extant members of the earliest divergent Bilateria, an interpretation that is supported by recent studies on the embryonic cleavage pattern and nervous system of acoels. This study has implications for understanding the evolution of major body plans, and for perceptions of the Cambrian evolutionary explosion.
Polyclad flatworms offer an excellent system with which to explore the evolution of larval structures and the ecological and developmental mechanisms driving flatworm and marine invertebrate life history evolution. Although the most common mode of development in polyclads might be direct development (where the embryo develops directly into a form resembling the young adult), there are many species that develop indirectly, through a planktonic phase with transient larval features, before settling to the sea floor. In this review, I introduce polyclad life history strategies, larval diversity and larval anatomical features (presenting previously unpublished micrographs of a diversity of polyclad larvae). I summarize what is known about polyclad larval development during the planktonic phase and the transition to the benthic juvenile. Finally, I discuss evolutionary and developmental scenarios on the origin of polyclad larval characters. The most prominent characters that are found exclusively in the
Rather than me going through the notes and boring you, today you will be using this website to go over the notes, videos, and pictures at your own speed. You will gather notes through answering questions which gives you examples of questions I could ask on the simple invertebrates test while adapting my notes to fully address the question. Feel free to use other materials/videos to explore these phylum and help clarify if you need. If you would like me to check on any of your answers/diagrams, please let me know ...
Why is flatworm mesoderm termed parenchyma?. Do flatworms have an open body space?. Which flatworms have rhabdites and what is their function?. What are three categories of symbiosis?. Distinguish commensalism, mutualism, and parasitism.. What are typical adaptations found in parasites?. How and why do free-living and parasitic flatworms differ in their tegument (epithelium or ectoderm)?. Which flatworms have a complex life history?. What are common intermediate/definitive hosts?. Briefly describe the specific life cycle:. a) Trematoda (flukes); b) Tapeworms. Describe and order these terms:. miracidium, sporocyst, rediae, cercariae, metacercariae. Why are some flatworm teguments termed syncytial?. What similar (analogous function do these structures have?. the opisthaptor (Monogenea) the scolex (Cestoda). What is a proglottid?. ...
Tapeworm: Tapeworm, any member of the invertebrate class Cestoda (phylum Platyhelminthes), a group of parasitic flatworms containing about 5,000 species. Tapeworms, which occur worldwide and range in size from about 1 mm (0.04 inch) to more than 15 m (50 feet), are internal parasites, affecting certain
Flatworms are triploblastic. This is unlike the diploblastic cnidarians. Like the cnidarians, however, flatworms possess only single opening to what is known as their gastrovascular cavity. Flatworms, unlike many other animals, lack a coelom, that is, a body cavity (the gastrovascular cavity, by contrast, technically is not a body cavity but instead a volume that is open to the outside world).. Though numerous free-living flatworms exist, most prominently the beautiful marine flatworms, a number of parasitic forms exist as well including tapeworms and also what are known as flukes. The latter are the cause of the disease schistosomiasis or (perhaps confusingly) snail fever (confusing since snails are not flatworms but instead serve as intermediate hosts for flukes).. ...
Flatworm: Flatworm, any of the phylum Platyhelminthes, a group of soft-bodied, usually much flattened invertebrates. A number of flatworm species are free-living, but about 80 percent of all flatworms are parasitic-i.e., living on or in another organism and securing nourishment from it. They are bilaterally
Spiral cleavage is a conserved, early developmental mode found in several phyla of Lophotrochozoans resulting in highly diverse adult body plans. While the cleavage pattern has clearly been broadly conserved, it has also undergone many modifications in various taxa. The precise mechanisms of how different adaptations have altered the ancestral spiral cleavage pattern are an important ongoing evolutionary question, and adequately answering this question requires obtaining a broad developmental knowledge of different spirally cleaving taxa. In flatworms (Platyhelminthes), the spiral cleavage program has been lost or severely modified in most taxa. Polyclad flatworms, however, have retained the pattern up to the 32-cell stage. Here we study early embryogenesis of the cotylean polyclad flatworm Maritigrella crozieri to investigate how closely this species follows the canonical spiral cleavage pattern and to discover any potential deviations from it. Using live imaging recordings and 3D reconstructions of
FERREIRA-SOBRINHO, Aristides e TAVARES-DIAS, Marcos. A study on monogenean parasites from the gills of some cichlids (Pisces: Cichlidae) from the Brazilian Amazon. Rev. Mex. Biodiv. [online]. 2016, vol.87, n.3, pp.1002-1009. ISSN 2007-8706. http://dx.doi.org/10.1016/j.rmb.2016.06.010.. The aim of this study was to investigate monogenean fauna in gills of Geophagus camopiensis, Pterophyllum scalare, Satanoperca jurupari, and Satanoperca acuticeps in a tributary from the Amazon River system in Brazil. A total of 2,148 monogenean specimens were collected from 140 fish examined from March 2012 to March 2013, and 84.3% of these fish were parasitized by 1 or more species. Such monogeneans were: Sciadicleithrum geophagi, Sciadicleithrum juruparii, Gussevia spiralocirra and Gyrodactylus sp. However, only G. camopiensis was parasitized by more than 1 species of monogenean, while S. jurupari and S. acuticeps were parasitized by the same species. Prevalence, mean intensity and mean abundance varied among ...
Apparently, acoels can harm corals by smothering them, which may hinder their respiration, feeding and sediment shedding capacities. The infestation may be contagious, since a Sandalolitha robusta (Quelch, 1886) mushroom coral, with more than 90 % acoel cover was observed to be in close contact with one of another species, Pleuractis granulosa (Klunzinger, 1879), that was only infested at the nearest side, implying that acoels crawled or swam from one coral to another. All presently reported mushroom coral species represent new host records for Waminoa (see Hoeksema et al. 2012). ...
Platyhelminthes tutorial all along with the key concepts of Characteristics of Platyhelminthes, Triploblastic Condition of Platyhelminthes, Acoelomate Condition, Classification of Flatworms, Structure Adults, Life Cycle of Tape Worm and Life cycle of Taenia
Protostomes are often considered a paraphyletic assemblage of worm-like animals characterized by the presence of a dorsal (or circumoesophageal) brain connected to a ventral longitudinal nerve cord often paired. Developmental characters such as the fate of the blastopore-which often becomes at least the adult mouth-and the mode of mesoderm formation are typical but not enough for diagnosing the clade (Nielsen 2001). The proposal of acoels and nemertodermatids as basal bilaterian members (Ruiz-Trillo et al. 1999, 2002; Jondelius et al. 2002; but see Philippe et al. 2007), preceding the split of protostomes and deuterostomes, renders protostomes paraphyletic. However, neither nemertodermatids nor acoels have a ventral nerve cord (e.g. Raikova et al. 2004a,b). The mode of mesoderm formation known in acoels (e.g. Henry et al. 2000; not known in nemertodermatids) differs from that of other bilaterians. Finally, the fate of the blastopore has not been described in either acoels (Boyer 1971; Henry et ...
G. salaris was first described in 1952,[8] after being removed from a Baltic strain[2] of Atlantic salmon kept at the Hölle Laboratory in Sweden, near to the river Indalsälv.[8] At the time, it was not thought to cause disease in the host fish.[8] The presence of G. salaris on fish became a World Organisation for Animal Health notifiable disease in 1983.[8] Catastrophic losses of Atlantic salmon occurred in Norway in the 1970s following the introduction of G. salaris. By 2001, the salmon populations of 41 Norwegian rivers had been virtually wiped out in this way.[4] Historically, Gyrodactylus-infected rivers have been treated with the indiscriminate pesticide/piscicide rotenone. A newer method of treatment employs dosing small volumes of aqueous aluminium and sulfuric acid into the river. A huge advantage of this method is its ability to kill the parasites without harming the hosts. This new method has shown promising results in Batnfjordelva and Lærdalselva, two rivers in Norway.[citation ...
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Flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of invertebrates. They are relatively simple animals. They have soft bodies. With about 25,000 known species, they are the largest phylum of animals without a body cavity. Flatworms can be found in marine, freshwater, and even damp terrestrial environments. A troublesome terrestrial example is the New Zealand flatworm, Arthurdendyus triangulatus. It is an invasive species which colonized large areas of Ireland and Scotland. It was brought there by accident in the 1960s. Since then, it has destroyed most of the indigenous earthworms. Holi Most flatworms (over 50%) are parasitic on other animals. There are four classes: ...
There are many competing hypotheses for the form of the evolutionary tree of animals. A traditional hypothesis is that the tree resembles a tuning fork: it has a short base and two main branches. However, there is recent molecular evidence that challenges part of this traditional hypothesis. Under the tuning fork model, the base of the tree includes structurally simple animals like sponges, corals, and their relatives. One main branch includes arthropods, molluscs, annelids, and nematodes. This branch, or a large part of it, usually is called the protostomes. The second main branch includes vertebrates (phylum Chordata), and starfish, sea urchins, and their relatives (phylum Echinodermata). This branch usually is called the deuterostomes. Flatworms (phylum Platyhelminthes), which include free living planarians as well as parasitic flukes and tapeworms may be placed very low on the protostome branch, or high on the trunk just below the protostome - deuterostome branching. ...
La sfârșitul tratamentului cu dexametazonă, doza filo platyhelminthes cestoda micșorată Pacienții cu insuficiență hepatică sau insuficiență renală necesită o Neofordex se enterobius vermicularis classificacao pentru tratarea pacienților adulți cu mielom multiplu, o formă de filo platyhelminthes cestoda care. Se cântăreşte fiecare fiolă şi se notează greutatea. Ca toate turbellaria, corpul lor este acoperit cu cilii - organul mișcării.
Rouse et al. (2016) gathered also phylogenomic data for one of the new species and sequenced complete mitochondrial genomes of all the new species. Their phylogenetic analyses were incongruent to each other. Phylogenomic analyses based on nearly 1200 nuclear protein coding genes found Xenacoelomorpha (composed in this dataset of one Acoela and two Xenoturbella species) as sister group to other Bilateria (Nephrozoa) (using site homogeneous models) or as a sister group to Protostomia (using site heterogeneous CAT model). Analyses based on mitochondrial proteins grouped Xenacoelomorpha (4 acoels and 4 xenoturbellid species) with deuterostomes. In the same issue of Nature where Rouse et als paper was published, Cannon et al. (2016) investigated the placement of Xenacoelomorpha more thoroughly, although using only one Xenoturbella species, but with many more Acoela species (7) and including Nemertodermatida (4 species). Cannon et al. (2016) added impressive amount of new transcriptome data ...
7. They are the first animals to illustrate the development of organ system. 8. A true body cavity or coelome is absent, and the space between the body organs is filled with loose parenchyma. 9.Muscular system is well developed. It is mesenchymal in origin. The system consists of circular, longitudinal and oblique muscles beneath the epidermis. 10. The alimentary canal is either absent or highly branched. Anus is absent. 11. Circulatory and respiratory systems are absent. 12. Excretory system consists of flame bulbs or flame cells or protonephridia connected to the excretory ducts. 13. Asexual multiplication and alternation of generations are seen in some examples. 14. Nervous system and sense organs are poorly developed. 15. Usually hermaphrodite animals. 16. Fertilization is internal and development may be direct or indirect. 17. May be free living (Turbellaria), ectoparasitic or endoparasitic. A few may be commensals. 18. Next topic is phylum Platyhelminthes classification. ...
Acoel flatworms can move in a variety of ways such as muscular and ciliary movements via cytoskeletal elements and their neural regulations. However, those locomotive mechanisms have not yet been fully elucidated. In this study, we examined the distribution of cytoskeletal elements including filamentous actin (F-actin) and tubulin, and the neuroanatomical organization in an acoelomorph worm, Praesagittifera naikaiensis (P. naikaiensis). Video microscopy revealed the elongation/contraction and the bending/rotation processes, and the ciliary gliding movement of P. naikaiensis. Histochemical and morphological analysis demonstrated that F-actin networks of inner longitudinal and outer circular muscle fibers were positioned along the entire surface of the body, and that the average distance between the circular muscle fibers in the contracted organism was decreased in the anterior region compared with that in the elongated organism. Electron microscopy showed dense bodies on the muscle cells of P. ...
Introduction: Nemertodermatida is the sister group of the Acoela, which together form the Acoelomorpha, a taxon that comprises bilaterally symmetric, small aquatic worms. While there are several descriptions of the embryology of acoel species, descriptions of nemertodermatid development are scarce. To be able to reconstruct the ground pattern of the Acoelomorpha it is crucial to gain more information about the development of several nemertodermatid species. Here we describe the development of the nemertodermatid Meara stichopi using light and fluorescent microscopic methods. Results: We have collected Meara stichopi during several seasons and reconstruct the complex annual reproductive cycle dependent on the sea cucumber Parastichopus tremulus. Using common fluorescent markers for musculature (BODIPY FL-phallacidin) and neurons (antibodies against FMRFamide, serotonin, tyrosinated-tubulin) and live imaging techniques, we followed embryogenesis which takes approximately 9–10 weeks. The ...
Nucleic acid and protein analyses have greatly informed the modern phylogenetic animal tree. These data come from a variety of molecular sources, such as mitochondrial DNA, nuclear DNA, ribosomal RNA (rRNA), and certain cellular proteins. Many evolutionary relationships in the modern tree have only recently been determined due to molecular evidence. For example, a previously classified group of animals called lophophorates, which included brachiopods and bryozoans, were long-thought to be primitive deuterostomes. Extensive molecular analysis using rRNA data found these animals to be protostomes, more closely related to annelids and mollusks. This discovery allowed for the distinction of the protostome clade, the lophotrochozoans. Molecular data have also shed light on some differences within the lophotrochozoan group, and some scientists believe that the phyla Platyhelminthes and Rotifera within this group should actually belong to their own group of protostomes termed Platyzoa.. Molecular ...
Background: Hox genes are critical for patterning the bilaterian anterior-posterior axis. The evolution of their clustered genomic arrangement and ancestral function has been debated since their discovery. As acoels appear to represent the sister group to the remaining Bilateria (Nephrozoa), investigating Hox gene expression will provide an insight into the ancestral features of the Hox genes in metazoan evolution.. Results: We describe the expression of anterior, central and posterior class Hox genes and the ParaHox ortholog Cdx in the acoel Convolutriloba longifissura. Expression of all three Hox genes begins contemporaneously after gastrulation and then resolves into staggered domains along the anterior-posterior axis, suggesting that the spatial coordination of Hox gene expression was present in the bilaterian ancestor. After early surface ectodermal expression, the anterior and central class genes are expressed in small domains of putative neural precursor cells co-expressing ClSoxB1, ...
The role of antagonistic organismal interactions in the production of long-term macroevolutionary trends has been debated for decades. Some evidence seems to suggest that temporal trends in predation frequency share a common causative mechanism with genus-level diversity, whereas studies on the role of parasites in shaping the evolutionary process are rare indeed. Digenean trematodes (Phylum Platyhelminthes) infest molluscs in at least one stage of their complex life cycle. Trematodes leave characteristic oval-shaped pits with raised rims on the interior of their bivalve hosts, and these pits are preserved in the fossil record. Here we survey 11,785 valves from the Pleistocene-Holocene deposits of the Po Plain and from nearby modern coastal environments on the northeast Adriatic coast of Italy. Of these, 205 valves exhibited trematode-induced pits. Trematodes were selective parasites in terms of host taxonomy and host body size. Infestation was restricted to lower ...
Liver fluke is a collective name of a polyphyletic group of parasitic trematodes under the phylum Platyhelminthes. They are principally parasites of the liver of various mammals, including humans. Capable of moving along the blood circulation, they can occur also in bile ducts, gallbladder, and liver parenchyma. In these organs, they produce pathological lesions leading to parasitic diseases. They have complex life cycles requiring two or three different hosts, with free-living larval stages in water. The body of liver flukes is leaf-like, and flattened. The body is covered with a tegument. They are hermaphrodites having complete sets of both male and female reproductive systems. They have simple digestive systems, and primarily feed on blood. The anterior end is the oral sucker opening into the mouth. Inside, mouth lead to a small pharynx which is followed by an extended intestine that runs through the entire length of the body. The intestine is heavily branched and anus is absent. Instead the ...
Tanytarsus spp. (JK) 3. Subfamily Orthocladiinae. Chaetocladius spp. (JK, LF) at least 2. Crictopus spp. (JK) 2. Eukiefferiella spp. (JK, LF) at least 2. Hydrobaenus sp. (JK, LF). Krenosmittia sp. (JK). Limnophyes sp. (JK). Metriocnemus sp. (JK, LF). Nanocladius sp (JK). Orthocladius sp. (LF). O. obumbratus cplx. (JK). O. mallochi (JK). O. abiskoensis (JK). O. thienemanni (JK). Paracricotopus sp. (JK). Parakiefferiella sp. (JK). Psectrocladius sp. (LF). Pseudorthocladius spp. (JK) 2. Pseudosmittia sp. (JK). Psilometriocnemus sp. (JK). Tvetenia sp. (JK). Corynoneura spp. (JK) 4. Thienemanniella sp. (JK). Family Tabanidae. Tabanus sp. (KF). Unknown sp. (KF). Family Stratiomyidae (JF). Subfamily Stratiomyinae. Caloparyphus sp. (KF). Hedriodiscus sp. or Odonomyia sp. (KF). Myxosargus sp. (KF). Family Empididae (JF). Family Muscidae. Limnophora sp. (GP, JF). Phylum Platyhelminthes. ...
In the first part of a national survey of gyrodactylid parasites, with special reference to Gyrodactylus salaris, funded by French administrations, two water basins harbouring Atlantic salmon were sampled: Brittany (7 rivers and 3 restocking farms) and the Adour basin in the Western Pyrenees (6 rivers and 1 restocking farm). 535 salmonids were collected and examined for G. salaris and other gyrodactylid species investigations. Identification procedure was performed by morphological examination and molecular analysis. Both methods led to the same conclusions with a high degree of consistency: Gyrodactylus salaris is declared absent from the examined samples and, therefore, can be considered absent from the sampled water basins with a very high level of confidence (over 99.4 %). A new species named Gyrodactylus teuchis was identified first by morphological examination and confirmed by molecular analysis. This result has been confirmed by an independent study performed in the same time (CUNNINGHAM ...
A new species of parasitic flatworm infecting turtles in Malaysia was named after outgoing US President Barack Obama. The scientist who discovered the worm says he has already named a number of species after people he
Parasitic Flatworms Molecular Biology, Biochemistry, Immunology and Physiology by A. G. Maule, N. J. Marks, Aaron G. Maule http://images.barnesandnoble.com/images/28100000/28108734.jpg Pages: 480pp Publisher: CABI Edition: March 2006
River Alness Salmon Fishing. An information resource for salmon and sea trout fishing on the River Alness, Ross-shire, Scotland. Salmon fishing lets and permits for the Novar beats.
I. Platyhelmithes Kayla Smith A. Structure and Function of Flatworms Period 2 1. Flatworms are the simplest animals with bilateral symmetry. 2. The tissues
Baguñà, J and Carranza, S and Paps, J and Ruiz-Trillo, I and Riutort, M (2000) Molecular taxonomy and phylogeny of the Tricladida. In: Littlewood, DTJ and Bray, RA, (eds.) Interrelationships of the Platyhelminthes. Systematics Association Special Volumes . CRC Press, 49 - 56. ISBN 9780748409037 ...
The early stages of development from the zygote (fertilized egg cell) to the larva has been examined in several species. The egg, as in all parasitic platyhelminths, is ectolecithal, that is, it contains an egg cell and a number of yolk cells. The egg of Multicotyle purvisi is laid at the 1-3 cell stage, whereas the eggs of Aspidogaster conchicola, A. indica and Lobatostoma manteri contain already fully developed larvae (references in Rohde, 1972). The early embryo of A. conchicola is anteriorly and posteriorly lined by yolk, and the so-called calotte cells at both poles of the egg line the yolk (Fig.1).The yolk is gradually resorbed by the embryo which now fills all of the egg and is lined by the calotte cells. Finally, the false anterior sucker as well as the posterior sucker and posterior appendage appear (Fig.1). ...
Gyrodactylus salaris is an extremely dangerous parasite and we are taking the most careful steps to make sure it does not enter any Scottish fishery. As such, in conjunction with Local Salmon Fishery Boards, we are adopting rigorous biosecurity procedures, which we are sure you will support. Please read the following very carefully: What are the risks? G. salaris has been shown to survive away from a live fish host for five-seven days at ambient river temperatures and for 78 hours and 42 hours at salinities of 10 ppt (parts per thousand) and 20 ppt, respectively. Risk is associated with movement of materials (animate and inanimate) that can carry low salinity water, which have recently been in contact with infected fish, and which have been kept in cool conditions sufficient to permit the temporary survival of the parasite away from live fish. Equipment or product that has been kept cool and damp and is transferred rapidly (within one week) may present high levels of risk. This notorious ...
The one species that is of concern to fisheries and fish farms is Gyrodactylus salaris. This is the notifiable one which is naturally widespread in the rivers of Finland, Russia and eastern Sweden draining into the Baltic Sea and which has been identified as the cause of loss of whole populations of Atlantic salmon parr and smolts in western Sweden and Norway. Epidemics of the organism occurred when it was transferred to areas where it is not naturally found and salmon exposed to the parasite for the first time had no evolved immunity (unlike those fish in the Baltic rivers which appear to be tolerant). This resulted in heavy losses of the susceptible fish and populations of salmon have been eliminated from more than twenty Norwegian rivers with the probable inevitable loss of some strain characteristics of those populations ...
This book examines recent research into the molecular biology, genomics and transcriptomics of, and novel control strategies for, flatworm parasites. These include Cestodes (tapeworms) and Trematodes (flukes, schistosomes etc), which are the cause of a number of diseases of medical and veterinary importance. The book explores three main areas: phylogeny, genetics and transcriptomes; immunobiology, host-parasite interaction and control; and protein function, metabolism and physiology. Where appropriate, comparisons are made between different parasitic flatworms and between parasitic and free-living species. The book concludes by exploring future avenues for research. Contributors to the book include leading authorities from Europe, North and South America, and Australia ...
He published work on platyhelminths and evolutionary cytogenetics. Benazzi is honoured in the polychaete name Diurodrilus ...
... ns possess the simplest lifecycle among the parasitic platyhelminths. They have no intermediate hosts and are ...
"Role of the tegument and gut in nutrient uptake by parasitic platyhelminths". Canadian Journal of Zoology. 82 (2): 211-232. doi ...
Ammonotelic animals include crustaceans, platyhelminths, cnidarians, poriferans, echinoderms, and other aquatic invertebrates. ...
In all platyhelminths, the nervous system is concentrated at the head end. Other platyhelminths have rings of ganglia in the ... Most platyhelminths have no anus and regurgitate undigested material through the mouth. However, some long species have an anus ... The lack of circulatory and respiratory organs limits platyhelminths to sizes and shapes that enable oxygen to reach and carbon ... Despite this difference in environments, most platyhelminths use the same system to control the concentration of their body ...
Platyhelminths: Trematoda)". Molecular Phylogenetics and Evolution. 57 (1): 144-151. doi:10.1016/j.ympev.2010.05.019. PMID ...
Platyhelminths: Trematoda)". Molecular Phylogenetics and Evolution 57(1): 144-151. doi:10.1016/j.ympev.2010.05.019. Martins R. ...
... in Baltic amber with a review of fossil and sub-fossil platyhelminths" (PDF). Invertebrate Biology. 122 (4): 308-312. doi: ...
Members of the molluscs, annelids, platyhelminths and nemerteans have all been shown to exhibit spiral cleavage in its ... The presence of spiral cleavage in animals such as platyhelminths could be difficult to correlate with some phylogenies. ... With this understanding, the presence of spiral cleavage in polyclad platyhelminths, as well as the more traditional Spiralia, ... platyhelminths and other taxa. The term Spiralia is applied to those phyla that exhibit canonical spiral cleavage, a pattern of ...
She has continued her research and is working on comparisons between polyclads, planarians and other types of platyhelminths ... who has studied and classified various types of platyhelminths. She was a recipient of the L'Oréal-UNESCO Fellowship for Women ...
The flatworms, flat worms, Platyhelminthes, Plathelminthes, or platyhelminths (from the Greek πλατύ, platy, meaning "flat" and ... In all platyhelminths, the nervous system is concentrated at the head end. This is least marked in the acoels, which have nerve ... Other platyhelminths have rings of ganglia in the head and main nerve trunks running along their bodies.[3][6] ... Most platyhelminths have no anus and regurgitate undigested material through the mouth. However, some long species have an anus ...
... platyhelminths, and rotifers). A modern consensus phylogenetic tree for the protostomes is shown below. The timing of clades ...
2004). "Role of the tegument and gut in nutrient uptake by parasitic platyhelminths". Canadian Journal of Zoology. 82: 211-232 ...
... platyhelminths, porifera, annelids, ctenophora, mollusca, echinodermata, myriapoda, agnatha, tunicata. Crustacea is a ...
Flatworms (Platyhelminths) and Polychaete worms (Annelids) are two such groups. References[change , change source]. .mw-parser- ...
There is considerable evidence that parasitic trematode platyhelminths (a type of fluke) have contributed to developmental ...
... platyhelminths MeSH B01.500.500.736.215 - cestoda MeSH B01.500.500.736.215.228 - diphyllobothrium MeSH B01.500.500.736.215.228. ...
... it is called a duo-gland This is a very common requirement and examples occur in Platyhelminths, both parasitic and free-living ...
... one species of monogean and four species of copepod and fourteen species of endoparasite made up of platyhelminths: four ...
... a behaviour which may mimic toxic or distasteful platyhelminths or nudibranchs and so provide some protection from predation. ...
... in Baltic amber with a review of fossil and sub-fossil platyhelminths". Invertebrate Biology. 122 (4): 308-312. doi:10.1111/j. ...
The annelids (Annelida, from Latin anellus, "little ring"),[2][a] also known as the ringed worms or segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies - some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. ...
P. flava's early cleavage pattern is similar to that of S. kowalevskii. The first and second cleavages from the single cell zygote of P. flava are equal cleavages, are orthogonal to each other and both include the animal and vegetal poles of the embryo. The third cleavage is equal and equatorial so that the embryo has four blastomeres both in the vegetal and the animal pole. The fourth division occurs mainly in blastomeres in the animal pole, which divide transversally as well as equally to make eight blastomeres. The four vegetal blastomeres divide equatorially but unequally and they give rise to four big macromeres and four smaller micromeres. Once this fourth division has occurred, the embryo has reached a 16 cell stage. P. flava has a 16 cell embryo with four vegetal micromeres, eight animal mesomeres and 4 larger macromeres. Further divisions occur until P. flava finishes the blastula stage and goes on to gastrulation. The animal mesomeres of P. flava go on to give rise to the larva's ...
... n sexual reproduction often involves a complex life cycle with both polyp and medusa stages. For example, in Scyphozoa (jellyfish) and Cubozoa (box jellies) a larva swims until it finds a good site, and then becomes a polyp. This grows normally but then absorbs its tentacles and splits horizontally into a series of disks that become juvenile medusae, a process called strobilation. The juveniles swim off and slowly grow to maturity, while the polyp re-grows and may continue strobilating periodically. The adults have gonads in the gastroderm, and these release ova and sperm into the water in the breeding season.[9][10] This phenomenon of succession of differently organized generations (one asexually reproducing, sessile polyp, followed by a free-swimming medusa or a sessile polyp that reproduces sexually)[25] is sometimes called "alternation of asexual and sexual phases" or "metagenesis", but should not be confused with the alternation of generations as found in plants. Shortened forms of ...
Most nematode species are dioecious, with separate male and female individuals, though some, such as Caenorhabditis elegans, are androdioecious, consisting of hermaphrodites and rare males. Both sexes possess one or two tubular gonads. In males, the sperm are produced at the end of the gonad and migrate along its length as they mature. The testis opens into a relatively wide seminal vesicle and then during intercourse into a glandular and muscular ejaculatory duct associated with the vas deferens and cloaca. In females, the ovaries each open into an oviduct (in hermaphrodites, the eggs enter a spermatheca first) and then a glandular uterus. The uteri both open into a common vulva/vagina, usually located in the middle of the morphologically ventral surface.[39] Reproduction is usually sexual, though hermaphrodites are capable of self-fertilization. Males are usually smaller than females or hermaphrodites (often much smaller) and often have a characteristically bent or fan-shaped tail. During ...
... is the second-largest phylum of invertebrate animals after the Arthropoda. The members are known as molluscs or mollusks[a] (/ˈmɒləsk/). Around 85,000 extant species of molluscs are recognized.[3] The number of fossil species is estimated between 60,000 and 100,000 additional species.[4] The proportion of undescribed species is very high. Many taxa remain poorly studied.[5] Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 8 or 9 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates-and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropods (snails and slugs) are ...
... ns are worms ranging from 2 to 720 mm (0.1 to 28.3 in) in length, with most species being under 10 cm (4 in). The sipunculan body is divided into an unsegmented, bulbous trunk and a narrower, anterior section, called the "introvert". Sipunculans have a body wall somewhat similar to that of annelids (though unsegmented) in that it consists of an epidermis without cilia overlain by a cuticle, an outer layer of circular and an inner layer of longitudinal musculature. The body wall surrounds the coelom (body cavity) that is filled with fluid on which the body wall musculature acts as a hydrostatic skeleton to extend or contract the animal. When threatened, Sipunculid worms can contract their body into a shape resembling a peanut kernel-a practice that has given rise to the name "peanut worm". The introvert is pulled inside the trunk by two pairs of retractor muscles that extend as narrow ribbons from the trunk wall to attachment points in the introvert. It can be protruded from the trunk by ...
The central nervous system of vertebrates is based on a hollow nerve cord running along the length of the animal. Of particular importance and unique to vertebrates is the presence of neural crest cells. These are progenitors of stem cells, and critical to coordinating the functions of cellular components.[18] Neural crest cells migrate through the body from the nerve cord during development, and initiate the formation of neural ganglia and structures such as the jaws and skull.[19][20][21] The vertebrates are the only chordate group with neural cephalisation, the concentration of brain functions in the head. A slight swelling of the anterior end of the nerve cord is found in the lancelet, a chordate, though it lacks the eyes and other complex sense organs comparable to those of vertebrates. Other chordates do not show any trends towards cephalisation.[13] A peripheral nervous system branches out from the nerve cord to innervate the various systems. The front end of the nerve tube is expanded by ...
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms.[138] Model organisms are in vivo models and are widely used to research human disease when human experimentation would be unfeasible or unethical.[139] This strategy is made possible by the common descent of all living organisms, and the conservation of metabolic and developmental pathways and genetic material over the course of evolution.[140] Studying model organisms can be informative, but care must be taken when extrapolating from one organism to another.[141]. In researching human disease, model organisms allow for better understanding the disease process without the added risk of harming a human. The species chosen will usually meet a determined taxonomic equivalency to humans, so as to react to disease or its treatment in a way that resembles human ...
The evolutionary relationships between the chordate groups and between chordates as a whole and their closest deuterostome relatives have been debated since 1890. Studies based on anatomical, embryological, and paleontological data have produced different "family trees". Some closely linked chordates and hemichordates, but that idea is now rejected.[4] Combining such analyses with data from a small set of ribosome RNA genes eliminated some older ideas, but opened up the possibility that tunicates (urochordates) are "basal deuterostomes", surviving members of the group from which echinoderms, hemichordates and chordates evolved.[42] Some researchers believe that, within the chordates, craniates are most closely related to cephalochordates, but there are also reasons for regarding tunicates (urochordates) as craniates' closest relatives.[4][43] Since early chordates have left a poor fossil record, attempts have been made to calculate the key dates in their evolution by molecular phylogenetics ...
... TRPLATT trplatt at aol.com Thu Aug 6 07:51:07 EST 1998 *Previous message: Schistosoma sequence ... Graham Kearn has recently published a new book entitled Parasitism and Platyhelminths published by Chapman & Hall. The book ...
Evolutionary biology of parasitic platyhelminths: The role of molecular phylogenetics. Title. Evolutionary biology of parasitic ...
... Author: Otero, Lucía; Bonilla, Mariana ... Thioredoxin and Glutathione Systems Differ in Parasitic and Free-Living Platyhelminths. DSpace/Manakin Repository. * DASH Home ... Thioredoxin and glutathione systems differ in parasitic and free-living platyhelminths. BMC Genomics 11:237.. ...
PLATYHELMINTHS from MCB MCB2010 at Broward College. PLATYHELMINTHS (THE FLATWORMS) 8) When a human eats the crayfish that has ... PLATYHELMINTHS - PLATYHELMINTHS(THE FLATWORMS 8 When a.... This preview shows document pages 1 - 2. Sign up to view the full ... Unformatted text preview: PLATYHELMINTHS (THE FLATWORMS) 8) When a human eats the crayfish that has not been sufficiently ...
The platyhelminths which do not have a body cavity surrounding the gut, have a solid type of body constitution. The mesoderm ... The platyhelminths which do not have a body cavity surrounding the gut, have a solid type of body constitution. The mesoderm ...
Phylogenetic relationships of GRs, TRs and TGRs of platyhelminths and mammals. TRs, GRs and TGRs from platyhelminths and ... Amino acid sequence alignment of TR, GR and TGRs of platyhelminths. Sec is indicated by U. The position of the redox active ... Structures and nucleotide sequence alignment of SECIS elements of TR and TGRs of platyhelminths. The SECIS elements were ... Platyhelminths (commonly known as flatworms) are a metazoan phylum that includes the neodermata lineage, composed exclusively ...
Septins of platyhelminths: Identification, phylogeny, expression and localization among developmental stages of Schistosoma ... Septins of platyhelminths: Identification, phylogeny, expression and localization among developmental stages of Schistosoma ...
3.1 Platyhelminths 228. 3.1.1 Digenea 230. 3.1.1.1 Development 230. 3.1.1.2 Morphology 232 ...
10 Turbellarian Platyhelminths --. 11 Parasitic Platyhelminths --. 12 Platyhelminth Host-Parasite Interface --. 13 Nemertea -- ... 10 Turbellarian Platyhelminths -- 11 Parasitic Platyhelminths -- 12 Platyhelminth Host-Parasite Interface -- 13 Nemertea -- IV ...
PLATYHELMINTHS; RADIATIONS; SENSITIVITY; TREMATODES 550700* -- Microbiology; 550100 -- Behavioral Biology. ...
Licence Application for Placing Alien Invertebrates (arthropods, annelids, nematodes, platyhelminths) on the Market. ... Licence Application for Experimental Releases of Alien Invertebrates (arthropods, annelids, nematodes, platyhelminths). ...
Platyhelminths have practically no fossil record. A few trace fossils have been reported that were probably made by ... More detailed classification of platyhelminths is available from the Tree of Life at the University of Arizona. To find out ... platyhelminths (Alessandrello et al., 1988), and fossil trematode eggs have been found in Egyptian mummies and in the dried ...
The most primitive type is known as a protonephridium and consists of a system of flame cells; it occurs in platyhelminths and ...
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Brooks, D. R. (1989a). A summary of the database pertaining to the phylogeny of the major groups of parasitic platyhelminths, ... Dubinina, M. N. (1976). [Platyhelminths of the class Amphilinoidea]. In "Problemy zoologii (Zool. Inst. A.N. SSSR)". ... Brooks, D. R. (1982). Higher level classification of parasitic platyhelminths and fundamentals of cestode classification. In " ...
Flatworms (platyhelminths) - these include the trematodes (flukes) and cestodes (tapeworms).. *Thorny-headed worms ( ...
Platyhelminths / genetics * Platyhelminths / physiology* * RNA Interference * RNA, Messenger / genetics * RNA, Messenger / ...
Commonly known as parasitic worms, this group includes the ACANTHOCEPHALA; NEMATODA; and PLATYHELMINTHS. Some authors consider ...
Platyhelminths / chemistry* * Platyhelminths / physiology * Receptors, Neuropeptide * Sequence Alignment * Structure-Activity ...
Correlating early evolution of parasitic platyhelminths to Gondwana breakup.. Badets M, Whittington I, Lalubin F, Allienne JF, ...
The flatworms, flat worms, Platyhelminthes, Plathelminthes, or platyhelminths (from the Greek πλατύ, platy, meaning "flat" and ... In all platyhelminths, the nervous system is concentrated at the head end. This is least marked in the acoels, which have nerve ... Other platyhelminths have rings of ganglia in the head and main nerve trunks running along their bodies.[3][6] ... Most platyhelminths have no anus and regurgitate undigested material through the mouth. However, some long species have an anus ...
Eudiplozoon nipponicum; fish parasite; monogenea; Platyhelminths; serpin; inhibitor Popis. Background: Serpins are a ...
He published work on platyhelminths and evolutionary cytogenetics. Benazzi is honoured in the polychaete name Diurodrilus ...
2004). "Role of the tegument and gut in nutrient uptake by parasitic platyhelminths". Canadian Journal of Zoology. 82: 211-232 ...
Part 1: Ages of Materia Medica and of early expeditions by westerners.- Electron microscopy of turbellarian platyhelminths - a ... Ultrastructural investigations on the differentiation of genital hard structures in free-living platy- helminths and their ...
Monogeneans possess the simplest lifecycle among the parasitic platyhelminths. They have no intermediate hosts and are ...
Zheng, Y. (2013) Phylogenetic analysis of the Argonaute protein family in platyhelminths. Mol Phylogenet Evol 66: 1050-1054.. * ...
Platyhelminths and acoels possess a possibly totipotent stem cell system. This stem cell pool continuously gives rise to all ...
  • Platyhelminths (commonly known as flatworms) are a metazoan phylum that includes the neodermata lineage, composed exclusively of parasitic taxa, and the turbellaria lineage, mostly composed of free-living taxa [ 1 ]. (biomedcentral.com)
  • Flatworms (platyhelminths) - these include the trematodes (flukes) and cestodes (tapeworms). (cdc.gov)
  • Platyhelminths, or flatworms, include both free-living and parasitic species. (eol.org)
  • an animal that lacks a coelom, for example platyhelminths (flatworms). (absp.org.uk)
  • Although some platyhelminths (flatworms) are free-living and nondestructive, many other species (particularly the flukes and tapeworms) parasitize humans, domestic animals, or both. (britannica.com)
  • Schistosomes are unique among platyhelminths (parasitic flatworms) in that they are dioecious (separate males and females) and dimorphic (two distinct forms) with chromosomal sex determination. (sanger.ac.uk)
  • Until recently, it was believed that there are two major varieties of helminth worms - roundworms (nematodes) and flatworms (platyhelminths). (globalhealingcenter.com)
  • The flatworms (Platyhelminths) show well defined organs (a structure formed of more than one tissue type, organized to function in a coordinated way to perfom some function) -- digestive, nervous, muscular, excretory, reproductive. (talkorigins.org)
  • Helminths are multicellular parasitic organisms belonging to a diverse taxonomic group of metazoans that compromise the phylum Platyhelminths, known as flatworms, including cestodes and trematodes, and Nematoda, known as roundworms, including Ascaris , hookworm, whipworms, filarial parasites, and others. (frontiersin.org)
  • In platyhelminths, as in nematodes, FLPs have a central role in somatic muscle function. (springer.com)
  • Platyhelminths are also abundantly endowed with neuropeptide Fs (NPFs), which appear absent from nematodes. (springer.com)
  • In nematodes and platyhelminths, there is an abundance of physiological evidence demonstrating that neuropeptides play critical roles in the biology of both free-living and parasitic helminths. (springer.com)
  • Over the years, close relationships have been suggested with platyhelminths (both cestodes and trematodes), crustaceans, nematodes, chelicerate arthropods, annelids, tardigrades, and myriapods (see historical overview in Almeida and Christoffersen 1999). (eol.org)
  • In this contribution we disentangle the evolutionary history of the let-7 locus, which was restructured independently in nematodes, platyhelminths and deuterostomes. (uni-leipzig.de)
  • Animals have incredible variation in their body shapes and ways of life, including the plant-like, immobile marine sponges that lack heads, eyes, limbs and complex organs, parasitic worms that live inside other organisms (e.g. nematodes, platyhelminths), and phyla with eyes, skeletons, limbs and complex organs that dominate the land in terms of species numbers (arthropods) and body size (chordates). (brightsurf.com)
  • Myxosporeans are known from aquatic annelids but parasitism of platyhelminths by myxosporeans has not been widely reported. (biomedcentral.com)
  • One group of animals that are poorly researched are the Lophotrochozoa, a group of animal phyla including annelids, molluscs, platyhelminths, rotifers and others. (otago.ac.nz)
  • From a human perspective, worms are important as soil conditioners ( e.g., annelids, aschelminths) and as parasites of people and domestic animals ( e.g., platyhelminths, aschelminths) and of crops ( e.g., aschelminths). (britannica.com)
  • Schistosomes belong to the phylum platyhelminths and reside in the intravascular system of the host. (prolekare.cz)
  • Septins of platyhelminths: Identification, phylogeny, expression and l" by Ana E. Zeraik, Gabriel Rinaldi et al. (gwu.edu)
  • As many of you may be aware, Prof. Graham Kearn has recently published a new book entitled 'Parasitism and Platyhelminths' published by Chapman & Hall. (bio.net)
  • Porifera Cnidaria Platyhelminths Nematoda Annelida Mollusca Arthropoda Echinodermata Chordata. (slideserve.com)
  • He published work on platyhelminths and evolutionary cytogenetics. (wikipedia.org)
  • Planarians are a group of free-living platyhelminths (triclads) best-known largely due to long-standing regeneration and pattern formation research. (mdpi.com)
  • Comparative analysis of cystatin superfamily in platyhelminths. (jove.com)
  • The early emergence of platyhelminths is contradicted by the agreement between 18S rRNA and Hox genes data. (tolweb.org)
  • In all platyhelminths, the nervous system is concentrated at the head end. (smore.com)
  • Monogeneans possess the simplest lifecycle among the parasitic platyhelminths. (wikipedia.org)
  • Platyhelminths and acoels possess a possibly totipotent stem cell system. (uibk.ac.at)
  • The extent of this group was subsequently more restricted, and at present the name Turbellaria is applied to all those (mainly free-swimming) Platyhelminths whose body is clothed externally with a ciliated epidermis (fig. 9), and which possess a mouth and (with the exception of one division) an alimentary canal, but are without an anus. (1902encyclopedia.com)
  • More detailed classification of platyhelminths is available from the Tree of Life at the University of Arizona. (berkeley.edu)
  • in the platyhelminths, the most physiological data has come from the blood fluke Schistosoma mansoni . (springer.com)
  • Schistosomes are unique among platyhelminths (parasitic flatworms) in that they are dioecious (separate males and females) and dimorphic (two distinct forms) with chromosomal sex determination. (sanger.ac.uk)
  • Platyhelminths (flatworms) include both trematodes (flukes) and cestodes (tapeworms). (as-publik.com)
  • Helminths are parasitic worms belonging to the crijevni helminti invertebrate phyla of nematodes roundworms and platyhelminths flatworms. (parohiaorsova.ro)
  • For example, the parasitic platyhelminths Cavalier Smith, T. Serves as storage area for eggs and sperm 3. (die-gmbh.info)