Functional stucture and toxins of nematocysts in jellyfish cnidarians

Mlacović, Petra (2016) Functional stucture and toxins of nematocysts in jellyfish cnidarians. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

Phylum Cnidaria is divided in four classes of which Anthozoa do not, but Scyphozoa, Cubozoa and Hydrozoa do have the shape of jellyfish. The main characteristic on which Cnidaria diverse from other animals is the existence of cnidocyts, specialised cells which have a role in capturing prey, defence and adhesion to the surface. There are three types of cnidocysts: spirocysts, ptychocysts and nematocysts. Spirocysts and ptychocysts are found in Anthozoa, while nematocysts are found only in jellyfish. There are more than 30 shapes of nematocysts which contain differently structured toxins. Nematocysts consist of shaft and tubule which when chemically or mechanically stimulated ejects and penetrates epidermis of the victim and releases its poison. The tubule is ejected because the pressure in the cell rises, that process of ejection is one of the fastest bio-mechanical processes in nature. There are two types of nematocysts: astomocnidae whose tubule is closed at the tip and stomocnidae whose tubule is opened at the tip. Stomocnidae are divided based on the differences in tubule thorns, morphology of the tubule and the length of the everted shaft and tubule compared to the length of closed shaft. Until today 156 different toxins from nemtocysts have been defined. Most common toxins are enzymes, neurotoxins, pore forming toxins and non-protein bioactive components. From all known jellyfish, the most famous ones are the most poisonous such as Chironex fleckeri and Physalia physalis and those that are spreaded all around the world such as Aurelia aurita and Pelagia noctiluca.

Item Type: Thesis (Bachelor's thesis)
Supervisor: Primc, Biserka
Date: 2016
Number of Pages: 15
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Palma Dizdarevic
Date Deposited: 11 May 2017 12:04
Last Modified: 11 May 2017 12:04
URI: http://digre.pmf.unizg.hr/id/eprint/5523

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