Entobdella soleae

Last updated

Entobdella soleae
Scientific classification
Kingdom:
Animalia
Phylum:
Platyhelminthes
Class:
Monogenea
Subclass:
Monopisthocotylea
Order:
Capsalidea
Family:
Capsalidae
Genus:
Entobdella
Species:
E. soleae
Binomial name
Entobdella soleae
van Beneden & Hesse, 1864

Entobdella soleae is a monogenean (Platyhelminth) skin parasite of the common sole, Solea solea , an important food fish. They are approximately 2 to 6 mm in length. It is flat, translucent, and has a large, disc-shaped haptor, a posterior organ used for semi-permanent attachment to the host. [1] Typically, 2-6 parasites are found on wild sole, but in intensive fish farms this can rise to 200-300 parasites per fish, causing skin inflammation and sometimes death of the sole. E. soleae can live up to 120 days in seawater. [2]

Contents

Life Cycle

The life cycle of Entobdella soleae follows the life patterns of their marine bottom-living host. The Solea solea would bury itself in the sediment for some time each day. The parasites are attached to the bottom of their host, in which when their hosts bury themselves, the parasite lays their eggs. The eggs are anchored to the sea bottom so that they wouldn't be swept away by the water currents. When the eggs hatched the oncomiracidia emerges and invades the anterior part of the upper surface of the fish. This part of the fish is the only part that is exposed when the fish is buried. After entering and developing on the upper surface of the fish, it migrates down toward the lower surface of the fish where they reach sexual maturity. Adult parasite would distribute throughout the lower surface of the host and are oriented with the adhesive organ upstream. [3]

Larvae

Entobdella soleae larvae are called oncomiracidia. They are free-swimming and ciliated. These oncomiracidia are likely to attach to the host's upper surface where they migrate forwards toward the fish's head and then migrate to the underside of the sole, where they remain. [4]

Attachment and detachment

Entobdella soleae utilizes suction through a posterior disc-shaped haptor to achieve semi-permanent attachment to the sole's skin. [5] E. soleae demonstrate host-specific behavior by attaching to the sole epidermis by the presence of sole mucous cells. [6]

The characteristic of the pad tegument might demonstrate a possible role in detachment of the parasite to the host. These features include an isolated tegument and the microvillus surface network of the pad tegument. [5]

Adhesive pad

The surface of the adhesive pads of E. soleae is encompassed by tegument that contains perforations of numerous rod-carrying ducts through pepper-pot apertures and ducts of spheroidal secretory bodies. Rods are distributed uniformly and intensely electron-dense within their ducts. Spheroidal secretory bodies are both tightly packed and have less electron density than rods. Moreover, the tegument on the surface of the parasite is isolated from the general tegumentary syncytium by a cell boundary. The tegument also contains secretory bodies. [5]

A 4-5 µm layer of cement bonds the adhesive pad of E. soleae via tegumental microvilli and the sole's epidermal furrows during attachment. Rod-shaped secretory bodies are the major substance of the cement. [5]

Locomotion

During locomotion on the skin of the sole, the anterior region of E. soleae temporarily attaches to the skin via two pads through an adhesive secretion. These adhesive pads contain two glandular secretions packaged in rods and spheroidal bodies. The locomotion step of E. soleae on the skin sole starts through elongation of the body with the haptor attached. Before attachment of the adhesive pads to the sole's skin, liquid spheroidal bodies quickly spread across the surface of the adhesive pads and bundles of rod-like secretory bodies leave the pepper-pot apertures of rod-carrying ducts. The synergy of both secretions produces the cement that binds the parasite to the host. [5]

The post-larval migration of E. soleae on the host’s surface ranges from 10–40 days; maintenance of navigational signals must remain intact over the entire period of migration. [7]

During migration, E. soleae larva utilizes the physical features of the host's scales as guidance for movement towards the head. The haptor attaches to the host’s scales as a lock and key mechanism where the axis of the haptor aligns with the longitudinal axis of the sole towards the head. [7]

Egg

Adult E. soleae lays tetrahedral eggs that have a tanned protein shell. A detachable operculum constitutes one of the tetrahedron corners of the egg. The cap-like operculum is bonded to the rest of the egg-shell by a thin cement layer. The opercular bond is strong, and operculum detachment only occurs through the actions of oncomiracidium and the secretion of hatching fluid by glands from the head region. The oncomiracidium of E. soleae escapes through an aperture of the operculum during hatching. [8]

The eggshell of E. soleae has a similar structural appearance to those of Fasciola hepatica, but without a membrane on the egg-shell lining. The egg's shell is produced by integration of shell material droplets from vitelline cells. Hatching occurs via chemical removal of the opercular cement and physical rupture of the rest of the egg-shell and opercular bond. [8]

Egg hatching of E. soleae induces a releaser response where the larva swims up and down the water column in the ocean to find the sole host. [7]

Hatching strategies

E. soleae consist of two hatching strategies: quick hatching in the presence of sole skin mucus and spontaneous hatching in the absence of the host. During the natural cycle of illumination, egg hatching is rhythmical: most larvae emerge a few hours after dawn. When fully developed eggs are in contact with sole body mucus during the illumination cycle, hatching is enhanced. The enhanced egg hatching indicates that the sole body mucus contains a potent hatching stimulant. [9]

Related Research Articles

<span class="mw-page-title-main">Flatworm</span> Phylum of soft-bodied invertebrates

The flatworms, flat worms, Platyhelminthes, or platyhelminths are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Being acoelomates, and having no specialised circulatory and respiratory organs, they are restricted to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion and egestion ; as a result, the food can not be processed continuously.

<span class="mw-page-title-main">Digenea</span> Class of flukes

Digenea is a class of trematodes in the Platyhelminthes phylum, consisting of parasitic flatworms with a syncytial tegument and, usually, two suckers, one ventral and one oral. Adults commonly live within the digestive tract, but occur throughout the organ systems of all classes of vertebrates. Once thought to be related to the Monogenea, it is now recognised that they are closest to the Aspidogastrea and that the Monogenea are more closely allied with the Cestoda. Around 6,000 species have been described to date.

<span class="mw-page-title-main">Monogenea</span> Class of ectoparasitic flatworms

Monogeneans, members of the class Monogenea, are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they have both male and female reproductive structures.

<span class="mw-page-title-main">Common sole</span> Species of fish

The common sole, Dover sole, or black sole is a species of flatfish in the family Soleidae. It is one of the largest fish in the Solea genus. It lives on the sandy or muddy seabed of the northern Atlantic and the Mediterranean Sea where it often partially immerses itself in the substrate. The upper side is greyish-brown while the underside is white. It grows to a maximum length of about 70 cm (28 in). The species is prized as a food fish, being caught mostly by trawling on the seabed.

<span class="mw-page-title-main">Cestoda</span> Class of flatworms

Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites.

Arhythmacanthidae is a family of parasitic worms from the order Echinorhynchida.

Tegument is a term in helminthology for the outer body covering of members of the phylum Platyhelminthes. The name is derived from a Latin word tegumentum or tegere, meaning "to cover". It is characteristic of flatworms including the broad groups of tapeworms and flukes. Once considered to be a non-living component, it is now known to be a dynamic cellular structure. In fact it is a living structure consisting of proteins, lipids, carbohydrates and RNA. It forms the protective layer and the host-parasite interface of the worms, serving both secretory and absorptive functions.

<i>Hymenolepis microstoma</i> Species of flatworm

Hymenolepis microstoma, also known as the rodent tapeworm, is an intestinal dwelling parasite. Adult worms live in the bile duct and small intestines of mice and rats, and larvae metamorphose in the haemocoel of beetles. It belongs to the genus Hymenolepis; tapeworms that cause hymenolepiasis. H. microstoma is prevalent in rodents worldwide, but rarely infects humans.

<span class="mw-page-title-main">Monopisthocotylea</span> Subclass of parasitic flatworms in the class Monogenea

The Monopisthocotylea are a subclass of parasitic flatworms in the class Monogenea.

<i>Pseudorhabdosynochus</i> Genus of flatworms

Pseudorhabdosynochus is a genus of monopisthocotylean monogeneans, included in the family Diplectanidae. The type-species of the genus is Pseudorhabdosynochus epinepheli .

<span class="mw-page-title-main">Diplectanidae</span> Family of flatworms

The Diplectanidae are a family of monopisthocotylean monogeneans. They are all parasitic on the gills of fish. Diplectanids are small animals, generally around 1 mm in length. As parasites, they can be extremely numerous, up to several thousand on an individual fish.

<i>Pseudorhabdosynochus manifestus</i> Species of flatworm

Pseudorhabdosynochus manifestus is a diplectanid monogenean parasite first found in host Epinephelus malabaricus near Nouméa, between its secondary gill lamellae. It can infest its host by the hundreds. It was ascribed that name because it was the most abundant species found while its descriptive study was taking place. As appreciated from studying juvenile specimens, the development of female organs precedes that of male organs in this species and is likely the case in other Pseudorhabdosynochus species.

<i>Pseudorhabdosynochus firmicoleatus</i> Species of flatworm

Pseudorhabdosynochus firmicoleatus is a diplectanid monogenean parasite on the gills of the Yellowedge grouper, Epinephelus flavolimbatus and the Snowy grouper, Epinephelus niveatus. It was described by Kritsky, Bakenhaster and Adams in 2015.

Acanthocotyle is a genus of monogenean fish skin parasites.

<i>Chimaericola leptogaster</i> Species of flatworm

Chimaericola leptogaster is a species of polyopisthocotylean monogenean in the family Chimaericolidae. It is ectoparasitic on the gills of the chimaera Chimaera monstrosa.

Hemibdella soleae is a marine species of leech in the family Piscicolidae and the type taxon of its genus. Found in the northeastern Atlantic Ocean, it is a parasite of flatfish such as the common sole.

<i>Polystoma integerrimum</i> Species of flatworm

Polystoma integerrimum is a flatworm (platyhelminth) from the class Monogenea found in amphibians in Asia and Europe. It is an endoparasite of frogs and toads and has an unusual life cycle which synchronises with that of its host.

Furcohaptor is a genus of monopisthocotylean monogeneans, belonging to the family Diplectanidae. All known species are parasitic on the gills of tonguefish.

<i>Sparicotyle chrysophrii</i> Species of worms

Sparicotyle chrysophrii is a species of monogenean, parasitic on the gills of the marine fish. It belongs to the family Microcotylidae. Its type-host is the gilt-head seabream.

<i>Pseudaxine trachuri</i> Species of worms

Pseudaxine trachuri is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Gastrocotylidae.

References

  1. ↑ Chaudhary, Kunal; Br; Zurawlow, on. "Entobdella soleae". Animal Diversity Web. Retrieved 2019-12-12.
  2. ↑ Kearn, G. C.; James, R.; Evans-Gowing, R. (1 November 1993). "Insemination and population density in Entobdella soleae, a monogenean skin parasite of the common sole, Solea solea". International Journal for Parasitology. 23 (7): 891–899. doi:10.1016/0020-7519(93)90055-4. ISSN   0020-7519. PMID   8314374.
  3. ↑ Kearn, G.C (1963). "The life cycle of the monogenean Entobdella soleae, a skin parasite of the common sole". Parasitology. 53 (1–2): 253–263. doi:10.1017/S0031182000072723. S2CID   85604069.
  4. ↑ Kearn, G. C. (1 April 1988). "The monogenean skin parasite Entobdella soleae: Movement of adults and juveniles from host to host (Solea solea)". International Journal for Parasitology. 18 (3): 313–319. doi:10.1016/0020-7519(88)90139-7. ISSN   0020-7519. PMID   3397212.
  5. 1 2 3 4 5 Kearn, G. C. (1 August 1986). "Role of chemical substances from fish hosts in hatching and host-finding in monogeneans". Journal of Chemical Ecology. 12 (8): 1651–1658. Bibcode:1986JCEco..12.1651K. doi:10.1007/BF01022371. ISSN   0098-0331. PMID   24305883. S2CID   19501591.
  6. ↑ Sukhdeo, M. V. K; Sukhdeo, S. C (1 March 2002). "Fixed behaviours and migration in parasitic flatworms". International Journal for Parasitology. The fourth International Symposium on Monogenea. 32 (3): 329–342. doi:10.1016/S0020-7519(01)00334-4. ISSN   0020-7519. PMID   11835973.
  7. 1 2 3 Kearn, G. C.; Evans-Gowing, R.; Tappenden, T. (April 1999). "The opercular bond in the egg-shell of the monogenean Entobdella soleae, a platyhelminth skin parasite of the common sole (Solea solea)". Parasitology. 118 (4): 433–438. doi:10.1017/S0031182099003996. ISSN   1469-8161. PMID   10340335.
  8. 1 2 Kearn, G. C.; Evans-Gowing, R. (1 October 1998). "Attachment and detachment of the anterior adhesive pads of the monogenean (platyhelminth) parasite Entobdella soleae from the skin of the common sole (Solea solea)". International Journal for Parasitology. 28 (10): 1583–1593. doi:10.1016/S0020-7519(98)00059-9. ISSN   0020-7519. PMID   9801917.
  9. ↑ Whittington, Ian D.; Cribb, Bronwen W.; Hamwood, Tamarind E.; Halliday, Judy A. (1 March 2000). "Host-specificity of monogenean (platyhelminth) parasites: a role for anterior adhesive areas?". International Journal for Parasitology. 30 (3): 305–320. doi:10.1016/S0020-7519(00)00006-0. ISSN   0020-7519. PMID   10719124.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.