Pasteuria ramosa: Difference between revisions
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==== Growth and sporulation ==== |
==== Growth and sporulation ==== |
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[[File:Pasteuria ramosa endospores.jpg|thumb|Endospores of P. ramosa.]] |
[[File:Pasteuria ramosa endospores.jpg|thumb|Endospores of P. ramosa.]] |
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''Pasteuria ramosa'' is an [[obligate]] pathogen and it can only grow inside its host. Transmission between hosts takes place through the [[Endospores|endospore]] stage, and is strictly [[Horizontal transmission|horizontal]]<ref name=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz_1996>{{cite journal | author=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz | date=1996 | title=Development, life cycle, ultrastructure and phylogenetic position of Pasteuria ramosa Metchnikoff 1888: rediscovery of an obligate endoparasite of Daphnia magna Straus | journal=Philosophical Transactions of the Royal Society, London, Series B | volume=351 | pages=1689-1701}} </ref>. These endospores are highly resistant to different environmental stresses and can remain in the environment for decades without any deleterious effects. The infection starts when a ''Daphnia'' has ingested a spore of ''P. ramosa'' during filter feeding. The spore activates and attaches to the host esophagus. The pathogen then enters the body cavity of the host by penetrating the esophagus wall. Once inside the body cavity, the bacterium begins to propagate in cauliflower like colonies. After the infection has spread throughout the host, the bacterium begins to sporulate. The spores are shed into the environment from the dead host and can remain in the sediment for decades while maintaining their infectivity <ref name= |
''Pasteuria ramosa'' is an [[obligate]] pathogen and it can only grow inside its host. Transmission between hosts takes place through the [[Endospores|endospore]] stage, and is strictly [[Horizontal transmission|horizontal]]<ref name=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz_1996>{{cite journal | author=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz | date=1996 | title=Development, life cycle, ultrastructure and phylogenetic position of Pasteuria ramosa Metchnikoff 1888: rediscovery of an obligate endoparasite of Daphnia magna Straus | journal=Philosophical Transactions of the Royal Society, London, Series B | volume=351 | pages=1689-1701}} </ref>. These endospores are highly resistant to different environmental stresses and can remain in the environment for decades without any deleterious effects. The infection starts when a ''Daphnia'' has ingested a spore of ''P. ramosa'' during filter feeding. The spore activates and attaches to the host esophagus. The pathogen then enters the body cavity of the host by penetrating the esophagus wall. Once inside the body cavity, the bacterium begins to propagate in cauliflower like colonies. After the infection has spread throughout the host, the bacterium begins to sporulate. The spores are shed into the environment from the dead host and can remain in the sediment for decades while maintaining their infectivity <ref name=Duneau, D., P. Luijckx, F. Ben-Ami, C. Laforsch, and D. Ebert_2011>{{cite journal | author=Duneau, D., P. Luijckx, F. Ben-Ami, C. Laforsch, and D. Ebert | date=2011 | title=Resolving the infection process reveals striking differences in the contribution of environment, genetics and phylogeny to host-parasite interactions | journal=Bmc Biology | volume=9 | pages=11 | doi=10.1186/1741-7007-9-11}} </ref>. |
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==== Pathogenicity ==== |
==== Pathogenicity ==== |
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The infection success of ''P. ramosa'' depends on its ability to attach to the host esophagus and to spread into its body cavity where the propagation of the pathogen takes place. The attachment step of the infection depends on the genotypes of the host and the bacterium, meaning that only certain host genotypes can be infected by certain strains of the bacterium <ref name=Luijckx, P., F. Ben-Ami, L. Mouton, L. Du Pasquier, and D. Ebert_2011>{{cite journal | author=Luijckx, P., F. Ben-Ami, L. Mouton, L. Du Pasquier, and D. Ebert | date=2011 | title=Cloning of the unculturable parasite Pasteuria ramosa and its Daphnia host reveals extreme genotype-genotype interactions | journal=Ecology letters | volume=14 | pages=125-131 | doi=10.1111/j.1461-0248.2010.01561.x}} </ref>, <ref name= |
The infection success of ''P. ramosa'' depends on its ability to attach to the host esophagus and to spread into its body cavity where the propagation of the pathogen takes place. The attachment step of the infection depends on the genotypes of the host and the bacterium, meaning that only certain host genotypes can be infected by certain strains of the bacterium <ref name=Luijckx, P., F. Ben-Ami, L. Mouton, L. Du Pasquier, and D. Ebert_2011>{{cite journal | author=Luijckx, P., F. Ben-Ami, L. Mouton, L. Du Pasquier, and D. Ebert | date=2011 | title=Cloning of the unculturable parasite Pasteuria ramosa and its Daphnia host reveals extreme genotype-genotype interactions | journal=Ecology letters | volume=14 | pages=125-131 | doi=10.1111/j.1461-0248.2010.01561.x}} </ref>, <ref name=Duneau, D., P. Luijckx, F. Ben-Ami, C. Laforsch, and D. Ebert_2011>{{cite journal | author=Duneau, D., P. Luijckx, F. Ben-Ami, C. Laforsch, and D. Ebert | date=2011 | title=Resolving the infection process reveals striking differences in the contribution of environment, genetics and phylogeny to host-parasite interactions | journal=Bmc Biology | volume=9 | pages=11 | doi=10.1186/1741-7007-9-11}} </ref>. During ''P. ramosa'' infection, the size of the Daphnia increases significantly. This phenomenon is known as pathogen-induced gigantism. The fecundity of the host is reduced due to the early induction of castration. In addition, the lifespan of the host is significantly reduced <ref name=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz_1996>{{cite journal | author=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz | date=1996 | title=Development, life cycle, ultrastructure and phylogenetic position of Pasteuria ramosa Metchnikoff 1888: rediscovery of an obligate endoparasite of Daphnia magna Straus | journal=Philosophical Transactions of the Royal Society, London, Series B | volume=351 | pages=1689-1701}} </ref>. |
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During ''P. ramosa'' infection, the size of the Daphnia increases significantly. This phenomenon is known as pathogen-induced gigantism. The fecundity of the host is reduced due to the early induction of castration. In addition, the lifespan of the host is significantly reduced <ref name=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz_1996>{{cite journal | author=Ebert, D., P. Rainey, T. M. Embley, and D. Scholz | date=1996 | title=Development, life cycle, ultrastructure and phylogenetic position of Pasteuria ramosa Metchnikoff 1888: rediscovery of an obligate endoparasite of Daphnia magna Straus | journal=Philosophical Transactions of the Royal Society, London, Series B | volume=351 | pages=1689-1701}} </ref>. |
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==== Host range ==== |
==== Host range ==== |
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Revision as of 14:28, 18 March 2016
Pasteuria ramosa
Pasteuria ramosa is a gram-positive, endospore-forming bacterium in the Bacillus/Clostridia clade within Firmicutes. It is an obligate pathogen with cladoceran crustaceans from the Daphnia genus serving as its hosts Cite error: The <ref> tag has too many names (see the help page).. An established and widely used coevolutionary model of host-pathogen interactions exists with P. ramosa and D. magnaCite error: The <ref> tag has too many names (see the help page).Cite error: The <ref> tag has too many names (see the help page)..
| Pasteuria ramosa | |
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Firmicutes |
| Class: | Bacilli |
| Order: | Bacillales |
| Family: | Pasteuriaceae |
| Genus: | Pasteuria |
| Species: | P. ramosa |
Characteristics
Growth and sporulation
Pasteuria ramosa is an obligate pathogen and it can only grow inside its host. Transmission between hosts takes place through the endospore stage, and is strictly horizontalCite error: The <ref> tag has too many names (see the help page).. These endospores are highly resistant to different environmental stresses and can remain in the environment for decades without any deleterious effects. The infection starts when a Daphnia has ingested a spore of P. ramosa during filter feeding. The spore activates and attaches to the host esophagus. The pathogen then enters the body cavity of the host by penetrating the esophagus wall. Once inside the body cavity, the bacterium begins to propagate in cauliflower like colonies. After the infection has spread throughout the host, the bacterium begins to sporulate. The spores are shed into the environment from the dead host and can remain in the sediment for decades while maintaining their infectivity Cite error: The <ref> tag has too many names (see the help page)..
Pathogenicity
The infection success of P. ramosa depends on its ability to attach to the host esophagus and to spread into its body cavity where the propagation of the pathogen takes place. The attachment step of the infection depends on the genotypes of the host and the bacterium, meaning that only certain host genotypes can be infected by certain strains of the bacterium Cite error: The <ref> tag has too many names (see the help page)., Cite error: The <ref> tag has too many names (see the help page).. During P. ramosa infection, the size of the Daphnia increases significantly. This phenomenon is known as pathogen-induced gigantism. The fecundity of the host is reduced due to the early induction of castration. In addition, the lifespan of the host is significantly reduced Cite error: The <ref> tag has too many names (see the help page)..
Host range
P. ramosa has been found in D. magna, D. pulex, D. longispina Cite error: The <ref> tag has too many names (see the help page)., D. dentifera,[1]and Moina rectirostris [2].
Coevolutionary model with Daphnia magna
P. ramosa has coevolved with its host Daphnia magna. The mode of coevolution in this system fits the model with negative frequency dependent selection where the rare genotype is favored since the more common host genotype is more likely to become the target of a specialized pathogen[3][4][5]
References
- ^ Auld, Stuart K. J. R.; Hall, Spencer R.; Housley Ochs, Jessica; Sebastian, Mathew; Duffy, Meghan A. (2014-08-01). "Predators and patterns of within-host growth can mediate both among-host competition and evolution of transmission potential of parasites". The American Naturalist. 184 Suppl 1: S77–90. doi:10.1086/676927. ISSN 1537-5323. PMID 25061679.
- ^ Sayre, R. M.; Wergin, W. P.; Davis, R. E. (1977-11-01). "Occurrence in Monia rectirostris (Cladocera: Daphnidae) of a parasite morphologically similar to Pasteuria ramosa (Metchnikoff, 1888)". Canadian Journal of Microbiology. 23 (11): 1573–1579. ISSN 0008-4166. PMID 922608.
- ^ Ebert, Dieter. "Host–parasite coevolution: Insights from the Daphnia–parasite model system". Current Opinion in Microbiology. 11 (3): 290–301. doi:10.1016/j.mib.2008.05.012.
- ^ Cite error: The named reference
Carius,was invoked but never defined (see the help page). - ^ Decaestecker, Ellen; Vergote, Adelien; Ebert, Dieter; De Meester, Luc (2003-04-01). "Evidence for strong host clone-parasite species interactions in the Daphnia microparasite system". Evolution; International Journal of Organic Evolution. 57 (4): 784–792. ISSN 0014-3820. PMID 12778548.