Die Große Kalifornische Schlüssellochschnecke (lat. Megathura crenulata, engl. Great Keyhole Limpet) ist eine Meeresschnecke aus der Familie der Schlitzschnecken (Fissurellidae).
Das Verbreitungsgebiet der Großen Kalifornischen Schlüssellochschnecken erstreckt sich von den Küsten Süd-Kaliforniens (Monterey Bucht) bis nach Mexiko. Dort leben sie in den Brandungszonen in Wassertiefen bis zu 40 m, bevorzugt in der unteren Gezeitenzone zwischen 3 und 12 m Tiefe auf felsigem Grund.[1]
Als Nahrung dienen der nachtaktiven Schnecke Manteltiere und Algen, die sie von Steinen, auf denen sie mit ihrem Fuß festgesaugt sind, zu sich nimmt. Die Schnecke kann bis zu 130 mm Länge erreichen, womit sie die größte Schnecke aus der Familie der Schlüssellochschnecken ist. Das „Schlüsselloch“, das bei der gesamten Familie vorhanden ist und ihr den Namen gibt, befindet sich im Zentrum des flachen Rückenschildes. Es handelt sich dabei um eine Körperöffnung, die der Schnecke zum Atmen und als Verdauungstrakt dienen, sowie die ausleitenden Genitalwege (pallialer Gonodukt) beherbergen. Ein besonderes Merkmal der Großen Kalifornischen Schlüssellochschnecke ist ihr den Rückenschild nahezu komplett überziehender Mantel. Der Mantel weist hellgraue bis schwarze, teilweise auch braune, Streifen auf.[2]
Aus der Hämolymphe von Megathura crenulata wird das hochmolekulare, auf einem Kupferkomplex basierende Sauerstofftransporterprotein Hämocyanin gewonnen. Dieses Schlitzschnecken-Hämocyanin (KLH) führt bei Säugetieren zu einem starken Immunstimulans und ist unter dem internationalen Freinamen Immunocyanin in einigen Ländern als Arzneistoff zur Behandlung von oberflächlichen Harnblasenkarzinomen zugelassen.[3]
Die Große Kalifornische Schlüssellochschnecke (lat. Megathura crenulata, engl. Great Keyhole Limpet) ist eine Meeresschnecke aus der Familie der Schlitzschnecken (Fissurellidae).
Megathura crenulata is a northeastern Pacific Ocean species of limpet in the family Fissurellidae[1] known commonly as the great keyhole limpet[2] or giant keyhole limpet.[3] Megathura is a monotypic genus; in other words, this is the only species in that genus. This species occurs along the rocky coast of western North America, its distribution extending from Southern California to the Baja California peninsula in Mexico. It is found in the intertidal zone and in the sea up to a depth of 33 meters.[3]
Limpets of this family have a hole at the top of the shell, the portal through which waste products are released. This makes them different from the true limpets, which release waste from the mantle beneath the shell. This species is one of the largest keyhole limpets.[4]
This species consumes a varied diet of plant, animal, protist, and algal material. It has been noted to consume filamentous cyanobacteria, diatoms, brown and red algaes such as seaweeds, seagrass, forams, hydrozoans, bryozoans, nematodes, bivalves, gastropods, crustaceans, and tunicates. The larger part of its diet is composed of brown and red algae, tunicates, hydrozoans of the genus Eudendrium and bryozoans of the genus Crisia.[5]
M. crenulata has been used for experimental studies on gamete agglutination. Its blood contains a hemocyanin that appears blue due to its copper content. This protein carries oxygen as hemoglobin does in vertebrates. Unlike hemoglobin, the hemocyanin is not bound to cells but is simply dissolved in the hemolymph, the fluid part of the blood.[6][7]
Keyhole limpet hemocyanin from Megathura crenulata is used as vaccine carrier protein. Keyhole limpet hemocyanin (KLH) is a copper containing respiratory protein, similar to hemoglobin in humans. KLH is a large protein that acts as the hapten carrier part of the vaccine component, and is so far thought to be non-toxic. The major potential use of KLH is for bladder carcinoma by stimulating a specific immune response, but there are many other medical uses such as stress assessment, understanding inflammatory conditions, and treating drug addiction. Vaccines and other KLH uses are in the research or trial phases. A liter of blood from a keyhole limpet will produce 20 grams of protein, which can be worth as much as $100,000.[8][9][10]
Living specimen of Megathura crenulata with mantle extended over much of its shell. Megathura crenulata is a northeastern Pacific Ocean species of limpet in the family Fissurellidae known commonly as the great keyhole limpet or giant keyhole limpet. Megathura is a monotypic genus; in other words, this is the only species in that genus. This species occurs along the rocky coast of western North America, its distribution extending from Southern California to the Baja California peninsula in Mexico. It is found in the intertidal zone and in the sea up to a depth of 33 meters.
La megathura crenulata est un mollusque pouvant mesure jusqu'à 12,5 centimètres de long. Cette espèce comestible est répandue le long de la Californie dans les zones de marées basses.
La megathura crenulata est un mollusque pouvant mesure jusqu'à 12,5 centimètres de long. Cette espèce comestible est répandue le long de la Californie dans les zones de marées basses.
Megathura crenulata (Sowerby I, 1825) è un mollusco della famiglia Fissurellidae, endemico delle zone costiere della California (Stati Uniti d'America), dalla baia di Monterey fino all'isola Asuncion al largo del Bassa California (Messico).[1] È l'unica specie nota del genere Megathura.[2]
Megathura crenulata (Sowerby I, 1825) è un mollusco della famiglia Fissurellidae, endemico delle zone costiere della California (Stati Uniti d'America), dalla baia di Monterey fino all'isola Asuncion al largo del Bassa California (Messico). È l'unica specie nota del genere Megathura.
Megathura crenulata is een slakkensoort uit de familie van de Fissurellidae.[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1825 door Sowerby I.
Bronnen, noten en/of referenties
Megathura crenulata, common name the "great keyhole limpet" or "giant keyhole limpet", là một loài limpet thuộc họ Fissurellidae. These keyhole limpets are large, growing up to 60–132 mm.[1] They are được tìm thấy ở the Eastern Pacific.[2]
Megathura là một monotypic genus, in other words, this is the only species in that genus.
Keyhole limpet hemocyanin from Megathura crenulata is used as vaccine carrier protein.
.JPG)
Megathura crenulata, common name the "great keyhole limpet" or "giant keyhole limpet", là một loài limpet thuộc họ Fissurellidae. These keyhole limpets are large, growing up to 60–132 mm. They are được tìm thấy ở the Eastern Pacific.
Megathura là một monotypic genus, in other words, this is the only species in that genus.
