A comparative study of the glandular and excretory systems of the oncomiracidia of the monogenean skin parasitesEntobdella hippoglossi, E. diademaandE. soleae

Parasitology ◽  
1974 ◽  
Vol 69 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Graham C. Kearn
Keyword(s):  
Comparative Study ◽  
Ventral Surface ◽  
The Body ◽  
Head Region ◽  
Hippoglossus Hippoglossus ◽  
Gland Cells ◽  
Solea Solea ◽  
The Common ◽  
Common Sole ◽  
Lateral Head

A comparison of the oncomiracidia of the monogenean skin parasitesEntobdella hippoglossifrom the halibut (Hippoglossus hippoglossus), E. diademafrom the sting ray (Dasyatis pastinaca) andE. soleaefrom the skin of the common sole (Solea solea) has revealed the presence of ‘body gland cells’, all of which have openings on the ventral or lateral surfaces of the larvae. In all three species there are two pairs of glands lying in the posterior region of the body proper with long ducts extending into the haptor and opening on its ventral surface. In addition to these two pairs of glands there are seven other pairs of body glands inE. hippoglossi, six pairs inE. diademaand two pairs inE. soleae.InE. soleaeall the ‘body gland cells’ are poorly developed in the oncomiracidium and are more conspicuous in post-oncomiracidia. The fate of the ‘body gland cells’ during post-oncomiracidial development has been studied inE. soleae, and their possible functions are discussed. The glands in the head region (anterior median, posterior median and lateral head glands) are similar in all three species. Gland cells associated with the alimentary system are less easy to observe but differences between the three species appear to be small.In the oncomiracidia of all three species the number of flame cells and their distribution are the same, but the oncomiracidia ofE. hippoglossiandE. diademahave loops in the excretory ducts anterior to the bladder and the bladders ofE. diademacontain refringent bodies.The oncomiracidial eyes ofE. hippoglossiandE. soleaehave lenses but the lenses are greatly reduced in the oncomiracidia ofE. diadema.In the three larvae there are small but characteristic differences in the shapes of the accessory sclerites.The oncomiracidium ofE. hippoglossihas not previously been described.

The production, transfer and assimilation of spermatophores by Entobdella soleae, a monogenean skin parasite of the common sole

Parasitology ◽  
1970 ◽  
Vol 60 (2) ◽  
pp. 301-311 ◽  
Author(s):  
G. C. Kearn
Keyword(s):  
Sea Water ◽  
Ventral Surface ◽  
Egg Laying ◽  
The Body ◽  
Marine Biological Association ◽  
Solea Solea ◽  
The Matrix ◽  
Self Fertilization ◽  
The Common ◽  
Common Sole

SUMMARYIt has been shown that mating involving mutual exchange of spermatophores takes place in the skin-parasitic monogenean Entobdella soleae from Solea solea. The spermatophores are attached to the ventral surface of the body in the region of the vaginal opening and they are sucked into the vagina after mating by muscular contractions of the vaginal region.Mating takes place between young individuals with no vitellaria and between fully mature egg-laying adults but there is no evidence that self-fertilization takes place.The apparatus which manufactures the spermatophores is described and the evidence indicates that spermatozoa are injected into the jelly-like matrix of the spermatophore as the matrix is being extruded into the surrounding sea-water.I would like to thank the Director and Staff of the Laboratory of the Marine Biological Association at Plymouth for providing excellent facilities for this work and I am particularly grateful to Mr J. E. Green, who kindly fed and maintained infected soles at the Laboratory.

Breathing Movements in Entobdella Soleae (Trematoda, Monogenea) from the Skin of the Common Sole

1962 ◽  
Vol 42 (1) ◽  
pp. 93-104 ◽  
Author(s):  
G. C. Kearn
Keyword(s):  
Oxygen Content ◽  
Sea Water ◽  
The Body ◽  
Scyliorhinus Canicula ◽  
Solea Solea ◽  
Flat Fish ◽  
The Common ◽  
The Relationship ◽  
Common Sole

An undulating movement of the body was observed in Entobdella soleae, a monogenean found on the blind surface of a mud-dwelling flat-fish, Solea solea, at Plymouth. The movement is described and shown to have a breathing function, the rate of undulation increasing with decreasing oxygen content of the ambient sea water and vice versa.The relationship between the movement and micro-habitat is discussed and the phenomenon is compared with breathing movements in other muddwelling animals.A similar movement was noted in three other skin-parasitic monogeneans: Acanthocotyle sp. from Raia clavata, Pseudocotyle squatinae from Squatina squatina and Leptocotyle minor from Scyliorhinus canicula.

The effects of fish skin mucus on hatching in the monogenean parasite Entobdella soleae from the skin of the common sole, Solea solea

Parasitology ◽  
1974 ◽  
Vol 68 (2) ◽  
pp. 173-188 ◽  
Author(s):  
Graham C. Kearn
Keyword(s):  
Constant Temperature ◽  
Dark Period ◽  
The Body ◽  
Fish Skin ◽  
Skin Mucus ◽  
Monogenean Parasite ◽  
Solea Solea ◽  
The Common ◽  
The Relationship ◽  
Common Sole

Previously it has been shown that eggs of the skin-parasitic monogenean Entobdella soleae, maintained free of host contamination at constant temperature (12 °C) and exposed to alternating 12 h periods of light and darkness, hatch during the first few hours of each period of illumination as a result of endogenous processes in the larva in conjunction with the illumination cycle. Washings, prepared by immersing the parasite's host (the common sole, Solea solea) for 1 h in seawater (just sufficient to cover the body), enhance this ‘morning’ hatching. Furthermore, the application of host washings during the latter half of the period of illumination or during the dark period also stimulates hatching. Experiments have shown that the hatching factor is present in sole skin mucus, is not destroyed by boiling for 5 min or by freezing and is produced by small soles measuring 4–5 cm in length as well as by larger soles (15–21 cm long).When eggs are incubated at about 12°C in the absence of fish washings, hatching begins about 30 days after laying, but there is evidence that some of the larvae inside their shells are fully developed and capable of hatching in response to host hatching factor 1–3 days earlier.When fish washings are added to eggs which range in age from 25 to more than 30 days (at 12 °C) many eggs are stimulated to hatch (in addition to ‘morning’ hatching as a result of endogenous rhythmical processes and the illumination cycle) and others fail to hatch. These remaining unhatched eggs, in the absence of further treatment with host hatching factor, will complete their development and subsequently will hatch during the ‘morning’ hours in response to the illumination cycle. Further contact with host hatching factor is likely to stimulate the hatching of some of these remaining eggs.The host hatching factor is not specific to S. solea; washings from plaice, dab, halibut, whiting and ray induce hatching in E. soleae. In experiments in which oncomiracidia were offered scales from dab and sole, most of the attached larvae were found on sole skin, irrespective of whether the hatching stimulant had been provided by dab or by sole.The relationship between the behaviour of the common sole and hatching phenomena in the skin parasite is discussed; hatching rhythms and the use of host hatching factors adapt the parasite to take advantage of most opportunities to infect the host.

scholarly journals Feeding in some monogenean skin parasites: Entobdella soleae on solea solea and Acanthocotyle Sp. on Raia clavata

1963 ◽  
Vol 43 (3) ◽  
pp. 749-767 ◽  
Author(s):  
G. C. Kearn
Keyword(s):  
Rapid Rate ◽  
Liquid Food ◽  
Circular Area ◽  
Gland Cells ◽  
Solea Solea ◽  
Elasmobranch Fish ◽  
The Common ◽  
Gill Parasites ◽  
Common Sole

Entobdella soleae, a monogenean skin parasite of the common sole was induced to feed on its host. The feeding organ (,pharynx-) is protruded during feeding and encloses a circular area of host skin. The gland cells in the feeding organ produce a proteolytic secretion which digests the epidermis of the fish. The liquid food is then pumped by the feeding organ into the intestinal diverticula, where it is absorbed.Acanthocotyle sp. from the skin of an elasmobranch fish, Raia clavata, feeds on epidermis in the same way as Entobdella soleae. Observations on other skin and gill-parasitic monopisthocotylineans indicate that the majority of them are epidermis feeders, although there is evidence that some gill parasites, for example Amphibdella torpedinis, may feed on blood.The evolution of parasitism in the Monogenea is tentatively attributed to the outstanding qualities offish epidermis as a food for a potential ectoparasite and in particular to its rapid rate of regeneration.

Determinacy of fecundity in sole (Solea solea) from the Bristol Channel

1990 ◽  
Vol 70 (4) ◽  
pp. 803-813 ◽  
Author(s):  
J. W. Horwood ◽  
M. Greer Walker
Keyword(s):  
Bay Of Biscay ◽  
English Channel ◽  
Potential Fecundity ◽  
Frequency Distributions ◽  
The North ◽  
Size Frequency ◽  
Solea Solea ◽  
The North Sea ◽  
The Common ◽  
Common Sole

Ovaries of the common sole (Solea solea (Linnaeus)) were collected prior to, or at the beginning of, spawning from the spawning grounds in the Bristol Channel. Size frequency distributions of oocytes over 100 μm are presented. They clearly show a break in the size frequency distributions, at about 170 μm, indicating that the production of new oocytes to be spawned that season had ceased. It indicates that the sole is a determinate spawner and that, at least for this population, an annual potential fecundity can be measured. Estimated annual fecundity at length of Bristol Channel sole is calculated, and values are compared with those found for sole from the North Sea, eastern English Channel and the Bay of Biscay.

Characterisation of three variants of estrogen receptor β mRNA in the common sole, Solea solea L. (Teleostei)

2007 ◽  
Vol 153 (1-3) ◽  
pp. 31-39 ◽  
Author(s):  
Elisa Caviola ◽  
Luisa Dalla Valle ◽  
Paola Belvedere ◽  
Lorenzo Colombo
Keyword(s):  
Estrogen Receptor ◽  
Estrogen Receptor Β ◽  
Solea Solea ◽  
The Common ◽  
Common Sole
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