| 词条 | Entobdella soleae |
| 释义 |
| name = Entobdella soleae | image = | image_caption = | regnum = Animalia | phylum = Platyhelminthes | classis = Monogenea | subclassis = Monopisthocotylea | ordo = Capsalidea | familia = Capsalidae | genus = Entobdella | species = E. soleae | binomial = Entobdella soleae | binomial_authority = van Beneden & Hesse, 1864 }}Entobdella soleae is a monogenean (Platyhelminth) skin parasite of the common sole, Solea solea, an important food fish. 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.[1] LarvaeEntobdella 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.[2]Attachment and detachmentEntobdella soleae utilizes suction through a posterior disc-shaped haptor to achieve semi-permanent attachment to the sole's skin.[3] E. soleae demonstrate host-specific behavior by attaching to the sole epidermis by the presence of sole mucous cells.[4]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.[3] Adhesive padThe 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.[3] 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.[3] LocomotionDuring 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.[3] 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.[5] 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.[5] EggAdult 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.[6] 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.[6] 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.[5] Hatching strategiesE. 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.[7]References1. ^{{cite journal | last1=Kearn | first1=G. C. | last2=James | first2=R. | last3=Evans-Gowing | first3=R. | title=Insemination and population density in Entobdella soleae, a monogenean skin parasite of the common sole, Solea solea | journal=International Journal for Parasitology | date=1 November 1993 | doi=10.1016/0020-7519(93)90055-4 | issn=0020-7519 | volume=23 | issue=7 | pages=891–899}} 2. ^{{cite journal | last=Kearn | first=G. C. | title=The monogenean skin parasite Entobdella soleae: Movement of adults and juveniles from host to host (Solea solea) | journal=International Journal for Parasitology | date=1 April 1988 | doi=10.1016/0020-7519(88)90139-7 | issn=0020-7519 | volume=18 | issue=3 | pages=313–319}} 3. ^1 2 3 4 {{cite journal | last=Kearn | first=G. C. | title=Role of chemical substances from fish hosts in hatching and host-finding in monogeneans | journal=Journal of Chemical Ecology | date=1 August 1986 | doi=10.1007/BF01022371 | issn=0098-0331 | volume=12 | issue=8 | pages=1651–1658}} 4. ^{{cite journal | last1=Sukhdeo | first1=M. V. K | last2=Sukhdeo | first2=S. C | title=Fixed behaviours and migration in parasitic flatworms | journal=International Journal for Parasitology | series=The fourth International Symposium on Monogenea | date=1 March 2002 | url=http://www.sciencedirect.com/science/article/pii/S0020751901003344 | doi=10.1016/S0020-7519(01)00334-4 | issn=0020-7519 | volume=32 | issue=3 | pages=329–342}} 5. ^1 2 {{cite journal | last1=Kearn | first1=G. C. | last2=Evans-Gowing | first2=R. | last3=Tappenden | first3=T. | title=The opercular bond in the egg-shell of the monogenean Entobdella soleae, a platyhelminth skin parasite of the common sole (Solea solea) | journal=Parasitology | date=April 1999 | issn=1469-8161 | volume=118 | issue=4 | pages=433–438}} 6. ^1 <{{cite journal | last1=Kearn | first1=G. C. | last2=Evans-Gowing | first2=R. | title=Attachment and detachment of the anterior adhesive pads of the monogenean (platyhelminth) parasite Entobdella soleae from the skin of the common sole (Solea solea) | journal=International Journal for Parasitology | date=1 October 1998| issn=0020-7519 | volume=28 | issue=10 | pages=1583–1593}} 7. ^{{cite journal | last1=Whittington | first1=Ian D. | last2=Cribb | first2=Bronwen W. | last3=Hamwood | first3=Tamarind E. | last4=Halliday | first4=Judy A. | title=Host-specificity of monogenean (platyhelminth) parasites: a role for anterior adhesive areas? | journal=International Journal for Parasitology | date=1 March 2000 | issn=0020-7519 | volume=30 | issue=3 | pages=305–320}}
2 : Monopisthocotylea|Animals described in 1864 |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。