Net slime molds
| Net slime molds | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Aplanochytrium with a typical network of mucous fibers |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Labyrinthulomycetes | ||||||||||||
| Dick , 2001 |
The labyrinthulomycetes or mucus networks (Labyrinthulomycetes) form a taxon within the Stramenopilen and are thus closer to brown algae , gold algae (in the broad sense, that is golden algae , diatoms and yellow-green algae ), Eipilzen and Hyphochytriales (only one order of Hyphochytriomycota ) used as with the slime molds or the real mushrooms . They mainly live in the sea, but some species can also be found in freshwater or terrestrial. The best known species parasitize on various marine plants, such as the seaweed , the sea lettuce or the giant kelp ( Macrocystis pyrifera ).
construction
The net slime molds are unicellular, egg-shaped to spindle-shaped organisms, each with a cell nucleus , which are connected to one another by mucous fibers and form large clusters of cells. The mucous fibers are hollow and have a reinforced outer wall; the individual cells live within these fibers and move around them. The entirety of the fibers forms a network, which is known as a network or filoplasmodium. The fibers, which consist of polysaccharides , are secreted by the individual cells with the help of special organelles , the outward-facing sagogenogens or bothrosomes.
Way of life
Very little is known about the way of life of the net slime mold. Some species parasitize on marine plants, with Labyrinthula macrocystis , for example, being feared as the causative agent of seaweed disease on the North Atlantic coasts. Other host plants are sea lettuce or various brown algae . Many other species live as saprobionts in water and on the detritus , some species also break down fishing nets . In fresh water, Labyrinthula species also infect aquatic plants and often cause weed removal of the water.
Reproduction
Mesh slime molds reproduce asexually through cell division or zoospore formation; sexual reproduction has only been described in the case of Labyrinthula . With asexual reproduction there is a longitudinal division and thus doubling of the unicellular organisms, which then migrate to the periphery of the network and enlarge it further.
Occasionally spore formation occurs, initiated by an aggregation of several cells at one point in the network. These cells change their shape by becoming rounder and at the same time surrounding themselves with thin cell envelopes, while the entire group is enclosed by another envelope. In this sorus there are several cell divisions and the resulting zoospores then leave the envelope.
The zoospores are flagellated by two flagella and, in the species of the genus Labyrinthula, have an orange-red eye spot on the flagellum apparatus , which is used to perceive light. Swimming freely, these zoospores look for new hosts or suitable substrates into which they can penetrate. This is followed by the production of the slime web and its renewed reproduction.
Systematics
According to the revised classification of eukaryotes, which was published in 2012 by Sina M. Adl and others, the reticulated slime molds form a taxon within the Diaphoretickes , in it the super-group Sar and are in turn assigned to the stramenopiles . Like some other taxa within this group, such as the egg fungi (Peronosporomycetes), they have no chloroplasts and have a heterotrophic diet .
Two families are distinguished within the net slime mold, the Labyrinthulaceae only containing the species of the genus Labyrinthula . These are characterized, among other things, by an eye spot on the flagellum apparatus and facultative sexual reproduction. The Thraustochytriacae contain several genera without the zoospore eye-spot:
literature
- Martin Schmiedeknecht: Department of Netzschlimpilze, Labyrinthulomycota in: Urania Pflanzenreich. Viruses, bacteria, algae, fungi. Urania-Verlag, Berlin 2000; Page 378; ISBN 3-332-01167-7
- Sina M. Adl, Alastair GB Simpson, Christopher E. Lane, Julius Lukeš, David Bass, Samuel S. Bowser, Matthew W. Brown, Fabien Burki, Micah Dunthorn, Vladimir Hampl, Aaron Heiss, Mona Hoppenrath, Enrique Lara, Line le Gall, Denis H. Lynn, Hilary McManus, Edward AD Mitchell, Sharon E. Mozley-Stanridge, Laura W. Parfrey, Jan Pawlowski, Sonja Rueckert, Laura Shadwick, Conrad L. Schoch, Alexey Smirnov, Frederick W. Spiegel: The Revised Classification of Eukaryotes . In: The Journal of Eukaryotic Microbiology . Volume 59, No. 5, September 28, 2012, doi: 10.1111 / j.1550-7408.2012.00644.x , ISSN 1550-7408 , ISSN 1066-5234 , pp. 429-493 (English; PDF file , 828, 83 KiB, in the Wiley Online Library by John Wiley & Sons, Inc. ).
Web links
- Chytrid Fungi Online (English)
Notes and evidence
- ↑ a b Sina M. Adl, Alastair GB Simpson, Christopher E. Lane, Julius Lukeš, David Bass, Samuel S. Bowser, Matthew W. Brown, Fabien Burki, Micah Dunthorn, Vladimir Hampl, Aaron Heiss, Mona Hoppenrath, Enrique Lara , Line le Gall, Denis H. Lynn, Hilary McManus, Edward AD Mitchell, Sharon E. Mozley-Stanridge, Laura W. Parfrey, Jan Pawlowski, Sonja Rueckert, Laura Shadwick, Conrad L. Schoch, Alexey Smirnov, Frederick W. Spiegel : The Revised Classification of Eukaryotes . In: The Journal of Eukaryotic Microbiology . Volume 59, No. 5, September 28, 2012, doi: 10.1111 / j.1550-7408.2012.00644.x , ISSN 1550-7408 , ISSN 1066-5234 , pp. 429-493 (English; PDF file , 828, 83 KiB, accessed from the Wiley Online Library by John Wiley & Sons, Inc. , and received on March 21, 2017).
- ↑ Dubey Manish Kumar, Upadhyay RS: Isolation and Characterization of Some Indian Hyphochytriomycetes . In: International Research Journal of Biological Sciences . Volume 2, No. 6, 2013, ISSN 2278-3202 , pp. 31–34, here: 31 (English; PDF file , 2.51 MiB, summary , first page at scribd.com ( Memento of the original from 22. March 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , Accessed and received on March 22, 2017).
- ↑ Sina M. Adl, Alastair GB Simpson, Christopher E. Lane, Julius Lukeš, David Bass, Samuel S. Bowser, Matthew W. Brown, Fabien Burki, Micah Dunthorn, Vladimir Hampl, Aaron Heiss, Mona Hoppenrath, Enrique Lara, Line le Gall, Denis H. Lynn, Hilary McManus, Edward AD Mitchell, Sharon E. Mozley-Stanridge, Laura W. Parfrey, Jan Pawlowski, Sonja Rueckert, Laura Shadwick, Conrad L. Schoch, Alexey Smirnov, Frederick W. Spiegel: The Revised Classification of Eukaryotes . In: The Journal of Eukaryotic Microbiology . Volume 59, No. 5, September 28, 2012, doi: 10.1111 / j.1550-7408.2012.00644.x , ISSN 1550-7408 , ISSN 1066-5234 , pp. 429-493 (English; PDF file , 828, 83 KiB, accessed from the Wiley Online Library by John Wiley & Sons, Inc. , and received on March 21, 2017). The assignment of labyrinthulomycetes to Stramenopilen was included already in the previous classification of eukaryotes by Sina M. Adl and other from 2005, but the latter were in it nor the no longer included in the classification daus the year 2012, group of Chromalveolata attributed (see: Sina M. Adl, Alastair GB Simpson, Mark A. Farmer, Robert A. Andersen, O. Roger Anderson, John R. Barta, Samual S. Bowser, Guy Brugerolle, Robert A. Fensome, Suzanne Fredericq, Timothy Y. James, Sergei Karpov, Paul Kugrens, John Krug, Christopher E. Lane, Louise A. Lewis, Jean Lodge, Denis H. Lynn, David G. Mann, Richard M. McCourt, Leonel Mendoza, Øjvind Moestrup, Sharon E. Mozley-Standridge, Thomas A. Nerad, Carol A. Shearer, Alexey V. Smirnov, Frederick W. Spiegel, Max FJR Taylor: The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists . In: The Journal of Eukaryotic Microbiology Volume 52, No. 5, October 19, 2005, doi: 10.1111 / j .1550-7408.2005.00053.x , ISSN 1550-7408 , ISSN 1066-5234 , pp. 399-451 (English; Full text )).
