Macrostomum

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Macrostomum
Macrostomum lignano

Macrostomum lignano

Systematics
Empire : Multicellular animals (Metazoa)
Trunk : Flatworms (Platyhelminthes)
Class : Vortex worms (Turbellaria)
Order : Macrostomida
Family : Macrostomidae
Genre : Macrostomum
Scientific name
Macrostomum
Schmidt , 1848

Macrostomum is a genus of flatworms and occurs worldwide. There are currently over 180 species described. These hermaphrodite and free-living flatworms are usually only a few millimeters long. Larger specimens (e.g. Macrostomum tuba ) can reach a body length of up to 5 mm. The body is usually transparent and the cross-section of smaller species appears round rather than dorsoventrally flattened. Species that are at home in flowing waters are well adapted to their environment with their streamlined construction.

Surname

The term " Macrostomum " means "loud-mouthed" and comes from the Greek μάκρος, macros , "large", and στόμα, stoma , "mouth". Compared to other vortex worms , species of the genus Macrostomum have a longer mouth that is connected to the intestine by a muscular throat. This gullet can in certain species extend to almost the width of the animal.

Way of life

Species of the genus Macrostomum can be found in water and in damp locations. Smaller species often live in running water while larger species are mostly found in stagnant water. In sea and brackish water species living talk often interstitial (in the interstices of the sediment), while copies in freshwater are often associated with aquatic plants. Many of these small worms feed on unicellular algae such as diatoms , from other zooplankton or small invertebrates of the benthos . Cannibalism is known in some cases and could be the reason why only one or a few species inhabit a common habitat at a time.

Reproduction

The reproductive organs of Macrostomum are relatively simple. The male sexual organs consist of two bilaterally arranged testes and spermatic ducts , a seminal vesicle , a granular secretion vesicle (vesicula granulorum), a penis (stiletto) and the genital pore. The female sexual apparatus consists of one or two ovaries , one or two fallopian tubes , the genital atrium and the female genital pore, which is surrounded by accessory sex glands. The variation in shape and size of the stiletto suggests the respective species.

Locomotion

The skin of Macrostomum is equipped with many small cilia , which enable smooth movement. There are also single or grouped adhesive structures (rhabdites) that help the animal to hold on to the ground. Many and particularly strong rhabdites are present at the posterior end. To hold on to the bottom, a vacuum is created. In an experiment it was shown that animals which are doused with water from the front are completely swept from the ventral side to the dorsal side. In doing so, however, they can still hold on to the substrate with the posterior end until a large part of the tail is finally detached from the ground and the animal is washed away.

Nervous system and sensory organs

Macrostomum's brain is simple. It consists of two ganglia with nerve processes and further nerve protuberances that extend into the epithelium . This enables the animal to perceive simple stimuli from the environment and react to them. The primitive eyes recognize light stimuli, but are unable to project an image. There are also known species which successfully live without eyes. The epidermis plays an important role in sensory perception. On it are difficult to bend, spiky appendages and sensory hairs, with which enemies can be perceived and bypassed.

species

Some types:

  • M. bicaudatum
  • M. dongyuanensis
  • M. heyuanensis
  • M. johni
  • M. lignano , a model organism for studies in different areas of biology. These include development, bioadhesion, regeneration, stem cell biology, aging, toxicology, genomics, and evolution.
  • M. tuba

Individual evidence

  1. ^ Schmidt, Eduard Oscar: The rhabdocoelen strudelworms (Turbellaria Rhabddocoela) of the sweet water . Friedrich Mauke, Jena 1848.
  2. ↑ a b Archived copy ( memento of the original from July 16, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Turbellaria database @1@ 2Template: Webachiv / IABot / devbio.umesci.maine.edu
  3. ↑ a b c http://macrostomorpha.info/
  4. ^ A b Frederick F. Ferguson: Monograph of the Macrostomine Worms of Turbellaria . In: Transactions of the American Microscopical Society . 73, No. 2, Jan. 1, 1954, pp. 137-164. doi : 10.2307 / 3223751 .
  5. ↑ a b c d Ting Sun, Lv Zhang, An-Tai Wang, Yu Zhang: Three new species of freshwater Macrostomum (Platyhelminthes, Macrostomida) from southern China . In: Zootaxa . tape 4012 , no. 1 , January 1, 2015, p. 120-134 , PMID 26623848 .
  6. ↑ a b c d e Ferguson, FF: A monograph of the genus Macrostomum O. Schmidt 1848. Part I. Zoologischer Anzeiger, 1939, pp. 7-20 , accessed on April 7, 2016 (English).
  7. ^ Ferguson, FF: Monograph of the macrostomine worms of turbellaria. Transactions of the American Microscopical Society, 1954, pp. 137-164 , accessed April 7, 2016 .
  8. ^ A b Jacinto Gamo, Ana Maria Leal-Zanchet: Freshwater microturbellarians (Platyhelminthes) from Rio Grande do Sul, Brazil . In: Revista Brasileira de Zoologia . tape 21 , no. 4 , p. 897-903 , doi : 10.1590 / S0101-81752004000400026 ( scielo.br [accessed April 6, 2016]).
  9. ↑ P. Ladurner, L. Schärer, W. Salvenmoser, RM 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 . tape 43 , no. 2 , May 1, 2005, p. 114-126 , doi : 10.1111 / j.1439-0469.2005.00299.x .
  10. ↑ Maxime Willems, Bernhard Egger, Carsten Wolff, Stijn Mouton, Wouter Houthoofd, Pamela Fonderie, Marjolein Couvreur, Tom Artois, Gaëtan Borgonie: Embryonic origins of hull cells in the flatworm Macrostomum lignano through cell lineage analysis: developmental and phylogenetic implications . In: Development Genes and Evolution . 219, No. 8, October 16, 2009, pp. 409-417. doi : 10.1007 / s00427-009-0304-x .
  11. ↑ Birgit Lengerer, Robert Pjeta, Julia Wunderer, Marcelo Rodrigues, Roberto Arbore, Lukas Schärer, Eugene Berezikov, Michael W Hess, Kristian Pfaller: Biological adhesion of the flatworm Macrostomum lignano relies on a duo-gland system and is mediated by a cell type -specific intermediate filament protein . In: Frontiers in Zoology . 11, No. 1, February 12, 2014. doi : 10.1186 / 1742-9994-11-12 . PMID 24520881 . PMC 4016567 (free full text).
  12. ^ B. Egger, P. Ladurner, K. Nimeth, R. Gschwentner, R. Rieger: The regeneration capacity of the flatworm Macrostomum lignano — on repeated regeneration, rejuvenation, and the minimal size needed for regeneration . In: Development Genes and Evolution . 216, No. 10, April 8, 2006, pp. 565-577. doi : 10.1007 / s00427-006-0069-4 . PMID 16604349 . PMC 2441584 (free full text).
  13. ↑ Peter Ladurner, Bernhard Egger, Katrien De Mulder, Daniela Pfister, Georg Kuales, Willi Salvenmoser, Lukas Schärer: Thomas CG Bosch (eds.): The Stem Cell System of the Basal Flatworm Macrostomum lignano ( en ). Springer Netherlands, January 1, 2008, ISBN 9781402082733 , pp. 75-94, doi : 10.1007 / 978-1-4020-8274-0_5 .
  14. ↑ Stijn Mouton, Maxime Willems, Bart P. Braeckman, Bernhard Egger, Peter Ladurner, Lukas Schärer, Gaetan Borgonie: The free-living flatworm Macrostomum lignano: A new model organism for aging research . In: Experimental Gerontology . 44, No. 4, April 1, 2009, pp. 243-249. doi : 10.1016 / j.exger.2008.11.007 .
  15. ↑ Maxime Willems, An-Sofie Stevens, Els Adriaens, Michelle Plusquin, Karen Smeets, Freddy Van Goethem, Philippe Vanparys, Colin Janssen, Jean-Paul Remon: An Adult Stem Cell Proliferation Assay in the Flatworm Model Macrostomum lignano to Predict the Carcinogenicity of Compounds . In: Applied In Vitro Toxicology . 1, No. 3, September 1, 2015, pp. 213-219. doi : 10.1089 / aivt.2015.0011 .
  16. ↑ Kaja Wasik, James Gurtowski, Xin Zhou, Olivia Mendivil Ramos, M. Joaquina Delás, Giorgia Battistoni, Osama El Demerdash, Ilaria Falciatori, Dita B. Vizoso: Genome and transcriptome of the regeneration-competent flatworm, Macrostomum lignano . In: Proceedings of the National Academy of Sciences . 112, No. 40, October 6, 2015, pp. 12462-12467. doi : 10.1073 / pnas.1516718112 . PMID 26392545 . PMC 4603488 (free full text).
  17. ↑ Lukas Schärer, D. Timothy J. Littlewood, Andrea Waeschenbach, Wataru Yoshida, Dita B. Vizoso: Mating behavior and the evolution of sperm design . In: Proceedings of the National Academy of Sciences . 108, No. 4, January 25, 2011, pp. 1490-1495. doi : 10.1073 / pnas.1013892108 . PMID 21220334 . PMC 3029721 (free full text).

Web links

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