The ultrastructure of the epidermis of the redia and cercaria of Parorchis acanthus, Nicoll. A study by scanning and transmission electron-microscopy

Parasitology ◽  
1971 ◽  
Vol 62 (3) ◽  
pp. 479-488 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Electron Micrographs ◽  
Technical Assistance ◽  
Ventral Surface ◽  
The Body ◽  
Muscle Fibres ◽  
Scanning Electron Micrographs ◽  
Large Area ◽  
Transmission Electron ◽  
Parorchis Acanthus ◽  
Scanning Electron

Scanning electron-micrographs have shown the covering of microvilli on the surface of the redia of Parorchis acanthus. In the contracted state the elongated microvilli with bulbous extremities seen in the surface grooves may be the result of compression. The surface of the epidermis of the cercaria is smooth on a large area of the ventral surface and lattice-like with microvilli, laterally, anteriorly, dorsally and on the tail. The spines on the body can be withdrawn into sheaths by the contraction of muscle fibres inserted into the basement lamina below each spine.I would like to express my sincere gratitude to Dr I. ap Gwynn of this department for preparing the scanning electron-micrographs and the School of Engineering Science, University of North Wales, Bangor for the use of their stereoscan. I should also like to thank Mr M. C. Bibby for technical assistance and Professor E. G. Gray and Dr W. Sinclair for assistance with the transmission electron-micrographs.

scholarly journals A Contribution towards the Life History of Parorchis acanthus Nicoll, A Trematode in the Herring Gull

1922 ◽  
Vol 12 (4) ◽  
pp. 829-832 ◽  
Author(s):  
Marie V. Lebour ◽  
Richard Elmhirst
Keyword(s):  
Intermediate Host ◽  
Mytilus Edulis ◽  
Final Host ◽  
Marine Bivalve ◽  
Herring Gull ◽  
Small Glass ◽  
History Of ◽  
The Common ◽  
Parorchis Acanthus ◽  
Glass Aquarium

Parorchis acanthus is a Trematode described by Nicoll (1907) from the bursa Fabricii and rectum of the Herring Gull, Larus argentatus; in 1906 he first described it as Zeugorchis acanthus. Originally found at St. Andrews, it is now known to be common at Millport and also occurs in gulls from the Northumberland coast, and probably is abundant elsewhere. Nicoll found it once in the Common Gull, Larus canus. In 1907 (Lebour, 1907) one of the present writers described a cercaria occurring in rediæ from Purpura lapillus. This was named Cercaria purpurœ sp. inq., and afterwards identified with young stages of Parorchis acanthus in the Herring Gull (Lebour, 1914). It was thus shown that the first host of this Trematode is Purpura lapillus and the final host the Herring Gull, but the intermediate host was unknown. Localities for the cercaria were Loch Ryan, Wigtownshire; Budle Bay, Fenham Flats and Cullercoats in Northumberland; Robin Hood's Bay in Yorkshire; and Millport. Adults occur at St. Andrews, Northumberland coast and Millport, as already stated.The Cercaria appeared to be closely related to Echinostomum cercariæ, and it was suggested (Lebour, 1914) that the intermediate host would probably be some marine bivalve, as it is often so with Echinostomum (e.g. E. secundum in Mytilus edulis and Cardium edule, E. leptosomum in Scrobicularia tenuis). This suggestion now proves to be correct, and we are able to show that the intermediate host of Parorchis acanthus is Mytilus edulis or Cardium edule.On August 13th, 1921, at the Millport Station some larval cercariæ were noticed by Elmhirst swimming in a small glass aquarium, which contained a collection of Purpura lapillus, Cardium edule and Mytilus edulis.

The ultrastructure of the fore-gut of the redia of Parorchis acanthus Nicoll (Digenea: Philophthalmidae) from the digestive gland of Nucella lapillus L

Parasitology ◽  
1983 ◽  
Vol 87 (1) ◽  
pp. 151-158 ◽  
Author(s):  
F. Gwendolen Rees
Keyword(s):  
Digestive Gland ◽  
Body Surface ◽  
Buccal Cavity ◽  
The Body ◽  
Unusual Feature ◽  
Nucella Lapillus ◽  
Cytoplasmic Inclusions ◽  
Parorchis Acanthus ◽  
Ventral Nucleus ◽  
Rapid Passage

SUMMARYThe fore-gut of the redia of Parorchis acanthus is ingestive in function. It consists of a buccal cavity, suctorial pharynx and an oesophagus divided into anterior and posterior regions. The syncytial lining is continuous with that covering the body surface, except for the posterior region of the oesophagus which is lined by a separate syncytium. This latter has different cytoplasmic inclusions and the unusual feature of a single ventral nucleus in the outer cytoplasmic epidermis. Intrinsic and extrinsic muscles are responsible, respectively, for the fairly rapid passage of food through the fore-gut and for support. Secretion bodies in the epidermis are probably discharged into the lumen and pass with food into the intestine where they may be involved in extracellular digestion. Young rediae feed mainly by mouth while older, immotile rediae absorb nutrients mainly through the body surface.

The ultrastructure of the intestine of the redia of Parorchis acanthus Nicoll (Digenea: Philophthalmidae) from the digestive gland of Nucella lapillus L

Parasitology ◽  
1983 ◽  
Vol 87 (1) ◽  
pp. 159-166 ◽  
Author(s):  
F. Gwendolen Rees
Keyword(s):  
Plasma Membrane ◽  
Digestive Gland ◽  
Lipid Bodies ◽  
Nucella Lapillus ◽  
Dense Bodies ◽  
Parenchyma Cells ◽  
Basal Plasma Membrane ◽  
Basal Plasma ◽  
Parorchis Acanthus

SUMMARYThe intestine of the redia of Parorchis acanthus is lined by a gastrodermis and surrounded by inner longitudinal and outer circular muscles. The gastrodermis consists of alternating rings of dense and lucent cells of similar dimensions, with similar nuclei and with microvilli on the lumenal surface. The dense cells contain ribosomes, dense secretion bodies, vesicles and a few lipid bodies. Ribosomes, dense bodies and lipids are absent from the lucent cells but vesicles are present which, as in the dense cells, pass along the microvilli to be discharged into the lumen. Both types of cells are secretory, absorptive and transportive. The lucent cells, in addition, store glycogen in areas of the cytoplasm devoid of organelles. Tips of processes from the parenchyma cells are engulfed in pockets in the basal plasma membrane, of both, facilitating transport of nutrients from the gastrodermis directly into the parenchyma

Molecular Cytogenetics in Digenean Parasites: Linked and Unlinked Major and 5S rDNAs, B Chromosomes and Karyotype Diversification

2015 ◽  
Vol 147 (2-3) ◽  
pp. 195-207 ◽  
Author(s):  
Daniel García-Souto ◽  
Juan J. Pasantes
Keyword(s):  
Molecular Cytogenetics ◽  
5S Rdna ◽  
B Chromosomes ◽  
Ruditapes Decussatus ◽  
Metazoan Parasites ◽  
Single Chromosome ◽  
Telomeric Sequences ◽  
Digenetic Trematodes ◽  
Parorchis Acanthus ◽  
Morphological Differences

Digenetic trematodes are the largest group of internal metazoan parasites, but their chromosomes are poorly studied. Although chromosome numbers and/or karyotypes are known for about 300 of the 18,000 described species, molecular cytogenetic knowledge is mostly limited to the mapping of telomeric sequences and/or of major rDNA clusters in 9 species. In this work we mapped major and 5S rDNA clusters and telomeric sequences in chromosomes of Bucephalus minimus, B. australis, Prosorhynchoides carvajali (Bucephaloidea), Monascus filiformis (Gymnophalloidea), Parorchis acanthus (Echinostomatoidea), Cryptocotyle lingua (Opisthorchioidea), Cercaria longicaudata, Monorchis parvus (Monorchioidea), Diphterostomum brusinae, and Bacciger bacciger (Microphalloidea). Whilst single major and minor rDNA clusters were mapped to different chromosome pairs in B. minimus and P. acanthus, overlapping signals were detected on a single chromosome pair in the remaining taxa. FISH experiments using major rDNA and telomeric probes clearly demonstrated the presence of highly stretched NORs in most of the digenean taxa analyzed. B chromosomes were detected in the B. bacciger samples hosted by Ruditapes decussatus. Although the cercariae specimens obtained from Donax trunculus, Tellina tenuis, and R. decussatus were in agreement with B. bacciger, their karyotypes showed striking morphological differences in agreement with the proposed assignation of these cercariae to different species of the genus Bacciger. Results are discussed in comparison with previous data on digenean chromosomes.

Effects of copper sulphate on in vitro encystment of the cercariae of Echinostoma caproni

2004 ◽  
Vol 78 (4) ◽  
pp. 371-372 ◽  
Author(s):  
B. Fried ◽  
J.L. Schneck
Keyword(s):  
Emergency Response ◽  
Cyst Wall ◽  
Copper Sulphate ◽  
Bile Salts ◽  
Spring Water ◽  
Echinostoma Caproni ◽  
Parorchis Acanthus ◽  
High Concentrations

AbstractThe effects of various concentrations of copper sulphate were studied on in vitro encystment of Echinostoma caproni in a Locke's–artificial spring water (ASW) (1:1) medium. Cercariae were killed in 10,000 mg l−1 CuSO4 in Locke's–ASW (1:1) within 24 h and extruded cystogenous material to produce an abnormal cyst wall. The ‘emergency response’ of encystment to high concentrations of copper reported for Parorchis acanthus cercariae did not occur in E. caproni. Concentrations of 1000 mg l−1 and 100 mg l−1 CuSO4 in Locke's–ASW (1:1) also killed the cercariae without encystment by 48 h. A concentration of 10 mg l−1 CuSO4 in Locke's–ASW (1:1) allowed for normal in vitro encystment within 48 h and these cysts were capable of excystation in a trypsin–bile salts medium.

scholarly journals Toxicity of anti-fouling biocides to Parorchis acanthus (Digenea: Philophthalmidae) cercarial encystment

2003 ◽  
Vol 54 ◽  
pp. 55-60 ◽  
Author(s):  
NJ Morley ◽  
KMY Leung ◽  
D Morritt ◽  
M Crane
Keyword(s):  
Parorchis Acanthus
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