Macrostomum lignano

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Macrostomum lignano
Macrostomum lignano under the microscope with a 400-fold magnification

Macrostomum lignano under the microscope with a 400-fold magnification

Systematics
Trunk : Flatworms (Platyhelminthes)
Class : Vortex worms (Turbellaria)
Order : Macrostomida
Family : Macrostomidae
Genre : Macrostomum
Type : Macrostomum lignano
Scientific name
Macrostomum lignano
Ladurner , Schärer , Salvenmoser , & Rieger , 2005

Macrostomum lignano is a free-living hermaphroditic flatworm . It is transparent and small in size; adults can grow up to 1.7 mm long. M. lignano belongs to the sandy meiofauna of the Adriatic Sea (Adriatic Sea) and occurs within the intertidal zone. Originally it was a model organism for research in developmental biology and the evolution of the bilateral body plan . The research fields were thenexpanded to include M. lignano , such as sexual selection , sexual conflict, aging, ecotoxicology and genome research .

Surname

The genus "Macrostomum" means "large mouth" and comes from the Greek μάκρος, macros, "large", and στόμα, stoma , mouth. The species lignano comes from the place where the species was found, namely on the sandy beaches and lagoons , near Lignano Sabbiadoro , Italy .

biology

Macrostomum lignano , like all flatworms, is an unsegmented bilateria without a secondary body cavity and has no specialized circulatory and respiratory organs . Unlike many other flatworms, the body is not flattened, but round in cross-section. The diffusion of oxygen and nutrients to the different parts of the body is ensured by their small size (adult worms reach 1.7 mm in length). M. lignano is a simultaneous hermaphrodite. Therefore, adult animals (12 days after hatching, at 20 ° C and enough food) form ovaries and testes and simultaneously produce male and female gametes . Reproduction occurs through mutual pairing. Macrostomum lignano has an enormous regenerative capacity due to neoblasts. These stem cells are totipotent and can give rise to all cell types, including the gonads . A severed head regenerates the posterior end for 10 days. In contrast, a severed posterior end can no longer regenerate the head.

Ecology and diffusion

The moist sand above the water level mark is an excellent M. lignano habitat
Moist sand samples with M. lignano

Macrostomum lignano lives in or above the intertidal zone in the spaces between the sand , usually in the upper 5–10 mm. It can survive in the sand with little moisture, but can also occur underwater during the tides. He prefers protected areas that are exposed to little or no waves, such as tidal lagoons . M. lignano feeds mainly on diatoms ( diatoms ). In a few cases from small invertebrates, occasionally also from eggs of other species, sometimes even from his own. He often comes along with other turbellaria , Gastrotricha , nematodes and numerous crustaceans like crayfish rudder ( Copepoda before). The density of worms varies widely, several hundred individuals can be found in one tablespoon of sand. When certain environmental factors such as drought or salinity increase, M. lignano can encapsulate itself with a soft shell that it secretes. This shell can dissolve again in a few minutes if conditions improve.

M. lignano was found only near Lignano Sabbiadoro (Italy): in the intertidal zones east of Bibione and Isola di Martignano, in natural and semi-natural beaches of the Laguna di Marano and the Isola Valle Vecchia.

swell

  1. ↑ a b c d e Peter Ladurner, Lukas Schärer, Willi Salvenmoser, Reinhard Rieger: A new model organism among the lower Bilateria and the use of digital microscopy in taxonomy of meiobenthic Platyhelminthes: Macrostomum lignano , n. Sp. (Rhabditophora, Macrostomorpha) . In: Journal of Zoological Systematics and Evolutionary Research . 43, No. 2, 2005, pp. 114-126. doi : 10.1111 / j.1439-0469.2005.00299.x .
  2. ↑ Ladurner P, Rieger R, Baguña J: Spatial distribution and differentiation potential of stem cells in hatchlings and adults in the marine platyhelminth Macrostomum sp .: A bromodeoxyuridine analysis . In: Developmental Biology . 226, 2000, pp. 231-241.
  3. ^ R Rieger, P Ladurner: The significance of muscle cells for the origin of mesoderm in Bilateria . In: Integrative Comparative Biology . 43, 2003, pp. 47-57. doi : 10.1093 / icb / 43.1.47 .
  4. ↑ http://evolution.unibas.ch/scharer/research/current_research/macrostomum_overview.html Evolutionary Research on Macrostomum species at the University of Basel
  5. ↑ S Mouton, M Willems, BP Braeckman, B Egger, P Ladurner, L Schärer, G Borgonie: The free-living flatworm Macrostomum lignano : A new model organism for aging research . In: Experimental Gerontology . 44, No. 4, 2009, pp. 243-249. doi : 10.1016 / j.exger.2008.11.007 . PMID 19111920 .
  6. ↑ http://www.cmk.uhasselt.be/english/onderzoek/groepen/biodiversiteit.asp#1 Eco-toxicology at Hasselt University
  7. ↑ http://www.macgenome.org/
  8. ↑ DB Vizoso, G Rieger, L Schärer: Goings-on inside a worm: functional hypotheses derived from sexual conflict thinking . In: Biological Journal of the Linnean Society . 99, No. 2, 2010, pp. 370-383. doi : 10.1111 / j.1095-8312.2009.01363.x .
  9. ↑ http://evolution.unibas.ch/scharer/research/current_research/macrostomum_mating_behaviour.html
  10. ↑ http://www.macgenome.org/neoblasts.html
  11. ↑ a b c http://evolution.unibas.ch/scharer/research/current_research/macrostomum_overview.html Unpublished data, Evolutionary Research on Macrostomum species at the University of Basel

Web links

Commons : Macrostomum lignano  - collection of images, videos and audio files