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added internal wikipedia link for "cytoplasmic incompatibility"
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* Feminization: infected males develop as females or infertile pseudo-females.
* Feminization: infected males develop as females or infertile pseudo-females.
* [[Parthenogenesis]]: reproduction of infected females without males. Some scientists have suggested that parthenogenesis may always be attributable to the effects of ''Wolbachia''.<ref>{{cite book |first1=Gerard J. |last1=Tortora |first2=Berdell R. |last2=Funke |first3=Cristine L. |last3=Case |title=Microbiology: an introduction |publisher=Pearson Benjamin Cummings |year=2007 |isbn=0805347909}}</ref> An example of a parthenogenic species is the ''Trichogramma'' wasp,<ref name="Knight2001"/> which has evolved to procreate without males with the help of ''Wolbachia''. Males are rare in this tiny species of insect, possibly because many have been killed by that very same strain of ''Wolbachia''.<ref>{{cite magazine |title=Garden Friends & Foes: Trichogramma Wasps |url=http://whatcom.wsu.edu/ag/homehort/pest/trichogramma.htm |first=Todd |last=Murray |journal=Weeder's Digest |publisher=Washington State University Whatcom County Extension |accessdate=16 July 2009}}<!-- possibly oclc=58592363 --></ref>
* [[Parthenogenesis]]: reproduction of infected females without males. Some scientists have suggested that parthenogenesis may always be attributable to the effects of ''Wolbachia''.<ref>{{cite book |first1=Gerard J. |last1=Tortora |first2=Berdell R. |last2=Funke |first3=Cristine L. |last3=Case |title=Microbiology: an introduction |publisher=Pearson Benjamin Cummings |year=2007 |isbn=0805347909}}</ref> An example of a parthenogenic species is the ''Trichogramma'' wasp,<ref name="Knight2001"/> which has evolved to procreate without males with the help of ''Wolbachia''. Males are rare in this tiny species of insect, possibly because many have been killed by that very same strain of ''Wolbachia''.<ref>{{cite magazine |title=Garden Friends & Foes: Trichogramma Wasps |url=http://whatcom.wsu.edu/ag/homehort/pest/trichogramma.htm |first=Todd |last=Murray |journal=Weeder's Digest |publisher=Washington State University Whatcom County Extension |accessdate=16 July 2009}}<!-- possibly oclc=58592363 --></ref>
* Cytoplasmic incompatibility: the inability of ''Wolbachia''-infected males to successfully reproduce with uninfected females or females infected with another ''Wolbachia'' [[Strain (biology)|strain]].
* [[Cytoplasmic incompatibility]]: the inability of ''Wolbachia''-infected males to successfully reproduce with uninfected females or females infected with another ''Wolbachia'' [[Strain (biology)|strain]].
Several species are so dependent on Wolbachia that they are unable to reproduce effectively without the bacteria in their bodies.<ref>{{Cite journal |last=Werren |first=John H. |year=2003 |month=February |title=Invasion of the Gender Benders: by manipulating sex and reproduction in their hosts, many parasites improve their own odds of survival and may shape the evolution of sex itself |journal=[[Natural History (magazine)|Natural History]] |volume=112 |issue=1 |page=58 |issn=0028-0712 |oclc=1759475 |url=http://findarticles.com/p/articles/mi_m1134/is_1_112/ai_97174198 |format=Reprint |accessdate=15 November 2008}}</ref>
Several species are so dependent on Wolbachia that they are unable to reproduce effectively without the bacteria in their bodies.<ref>{{Cite journal |last=Werren |first=John H. |year=2003 |month=February |title=Invasion of the Gender Benders: by manipulating sex and reproduction in their hosts, many parasites improve their own odds of survival and may shape the evolution of sex itself |journal=[[Natural History (magazine)|Natural History]] |volume=112 |issue=1 |page=58 |issn=0028-0712 |oclc=1759475 |url=http://findarticles.com/p/articles/mi_m1134/is_1_112/ai_97174198 |format=Reprint |accessdate=15 November 2008}}</ref>


Revision as of 14:28, 3 February 2010

Wolbachia
Transmission electron micrograph of Wolbachia within an insect cell.
Credit:Public Library of Science / Scott O'Neill
Scientific classification
Kingdom:
Bacteria
Phylum:
Proteobacteria
Class:
Alphaproteobacteria
Order:
Rickettsiales
Family:
Rickettsiaceae
Genus:
Wolbachia

Wolbachia is a genus of radical feminist bacteria which infects arthropod species, including a high proportion of insects (~60% of species). It is one of the world's most common parasitic microbes and is possibly the most common reproductive parasite in the biosphere. One study concludes that more than 16% of neotropical insect species carry this bacterium[1] and as many as 25-70% of all insect species are estimated to be potential hosts.[2]

History

The bacterium was first identified in 1924 by M. Hertig and S. B. Wolbach in Culex pipiens, a species of mosquito. Hertig formally described the genus in 1936 as Wolbachia pipientis.[3] There was little interest after the discovery until 1971 when it was discovered that Culex mosquito eggs were killed when the sperm of Wolbachia-infected males fertilized infection-free eggs (cytoplasmic incompatibility).[4] In 1990, Richard Stouthamer of the University of California, Riverside discovered that Wolbachia can make males dispensable in some species.[5] It is today of considerable interest due to its ubiquitous distribution and many different evolutionary interactions.

Role in sexual differentiation of hosts

Within arthropods, Wolbachia is notable for significantly altering the reproductive capabilities of its hosts. These bacteria can infect many different types of organs, but are most notable for the infections of the testes and ovaries of their hosts.

Wolbachia are known to cause four different phenotypes:

  • Male killing: death of infected males.
  • Feminization: infected males develop as females or infertile pseudo-females.
  • Parthenogenesis: reproduction of infected females without males. Some scientists have suggested that parthenogenesis may always be attributable to the effects of Wolbachia.[6] An example of a parthenogenic species is the Trichogramma wasp,[5] which has evolved to procreate without males with the help of Wolbachia. Males are rare in this tiny species of insect, possibly because many have been killed by that very same strain of Wolbachia.[7]
  • Cytoplasmic incompatibility: the inability of Wolbachia-infected males to successfully reproduce with uninfected females or females infected with another Wolbachia strain.

Several species are so dependent on Wolbachia that they are unable to reproduce effectively without the bacteria in their bodies.[8]

Wolbachia are present in mature eggs, but not mature sperm. Only infected females pass the infection on to their offspring. One study on infected woodlice showed that the broods of infected organisms had a higher proportion of females than their uninfected counterparts.[9] It is thought that Wolbachia, especially Wolbachia-caused cytoplasmic incompatibility, may be important in promoting speciation.[10][11]

Horizontal gene transfer and genomics

The first Wolbachia genome to be determined was that of one that infects Drosophila melanogaster flies[12]. This genome was sequenced at The Institute for Genomic Research in a collaboration between Jonathan Eisen and Scott O'Neill. The second Wolbachia genome to be determined was one that infects Brugia malayi nematodes[13]. Genome sequencing projects for several other Wolbachia strains are in progress. A complete copy of the Wolbachia genome sequence was found within the genome sequence of the fruit fly Drosophila ananassae and large segments were found in 7 other Drosophila species.[14]

In an application of DNA barcoding to the identification of species of Protocalliphora flies, it was found that several distinct morphospecies had identical cytochrome c oxidase I gene sequences, most likely through horizontal gene transfer by Wolbachia species as they jump across host species.[15] As a result, Wolbachia can cause misleading results in molecular cladistical analyses.[16]

Wolbachia has been found to confer Drosophila hosts with resistance against certain RNA virus infections.[17]

Applications to human health

Outside of insects, Wolbachia infects a variety of isopod species, spiders, mites, and many species of filarial nematodes (a type of parasitic worm), including those causing onchocerciasis ("River Blindness") and elephantiasis in humans as well as heartworms in dogs. Not only are these disease-causing filarial worms infected with Wolbachia, but Wolbachia seem to play an inordinate role in these diseases. A large part of the pathogenicity of filarial nematodes is due to host immune response toward their Wolbachia. Elimination of Wolbachia from filarial nematodes generally results in either death or sterility.[18] Consequently, current strategies for control of filarial nematode diseases include elimination of Wolbachia via the simple doxycycline antibiotic rather than far more toxic anti-nematode medications.[19]

The use of modified strains of Wolbachia to control mosquito populations has also been a topic of research.[20] [21] Wolbachia can be used to control dengue and malaria by eliminating older insects that contain more parasites. Allowing younger insects to survive removes selection pressure for evolution of resistance.[22][23]

See also

References

  1. ^ Werren, J.H.; Guo, L; Windsor, D. W. (1995). "Distribution of Wolbachia in neotropical arthropods". Proc. R. Soc. London Ser. B. 262: 147–204.
  2. ^ Kozek, Wieslaw J.; Rao, Ramakrishna U. (2007). "The Discovery of Wolbachia in Arthropods and Nematodes – A Historical Perspective". Issues in Infectious Diseases. 5 (Wolbachia: A Bug’s Life in another Bug): 1–14. doi:10.1159/000104228.
  3. ^ Hertig, Marshall; Wolbach, S. Burt (1924). "Studies on Rickettsia-like microorganisms in insects". Journal of Medical Research. 44: 329–74. PMC 2041761.
  4. ^ Yen, J. H.; Barr, A. R. (1971). "New hypothesis of the cause of cytoplasmic incompatibility in Culex pipiens". Nature. 232: 657–658. doi:10.1038/232657a0. PMID 4937405.
  5. ^ a b Knight, Jonathan (5 July 2001). "Meet the Herod Bug". Nature. 421: 12–14. doi:10.1038/35083744. PMID 11452274.
  6. ^ Tortora, Gerard J.; Funke, Berdell R.; Case, Cristine L. (2007). Microbiology: an introduction. Pearson Benjamin Cummings. ISBN 0805347909.
  7. ^ Murray, Todd. "Garden Friends & Foes: Trichogramma Wasps". Weeder's Digest. Washington State University Whatcom County Extension. Retrieved 16 July 2009.
  8. ^ Werren, John H. (2003). "Invasion of the Gender Benders: by manipulating sex and reproduction in their hosts, many parasites improve their own odds of survival and may shape the evolution of sex itself" (Reprint). Natural History. 112 (1): 58. ISSN 0028-0712. OCLC 1759475. Retrieved 15 November 2008. {{cite journal}}: Unknown parameter |month= ignored (help)
  9. ^ Rigaud, Thierry; Moreau, Jérôme; Juchault, Pierre (1999). "Wolbachia infection in the terrestrial isopod Oniscus asellus: sex ratio distortion and effect on fecundity". Heredity. 83 (4): 469–475. doi:10.1038/sj.hdy.6885990. ISSN 0018-067X. OCLC 1752017. PMID 10583549. Retrieved 16 July 2009. {{cite journal}}: Unknown parameter |month= ignored (help) However, the broods also often consisted of fewer eggs than the broods of the uninfected Oniscus asellus.
  10. ^ Zimmer, Carl (2001). "Wolbachia: A Tale of Sex and Survival". Science. 292 (5519): 1093–5. doi:10.1126/science.292.5519.1093. PMID 11352061.
  11. ^ Telschow, Arndt; Flor, Matthias; Kobayashi, Yutaka; Hammerstein, Peter; Werren, John H. (2007). "Wolbachia-induced unidirectional cytoplasmic incompatibility and speciation: mainland-island model". PLoS ONE. 2 (1): e701. doi:10.1371/journal.pone.0000701. PMC 1934337. PMID 17684548.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  12. ^ Wu M, Sun LV, Vamathevan J; et al. (2004). "Phylogenomics of the reproductive parasite Wolbachia pipientis wMel: a streamlined genome overrun by mobile genetic elements". PLoS Biol. 2 (3): E69. doi:10.1371/journal.pbio.0020069. PMC 368164. PMID 15024419. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
  13. ^ Foster J, Ganatra M, Kamal I; et al. (2005). "The Wolbachia genome of Brugia malayi: endosymbiont evolution within a human pathogenic nematode". PLoS Biol. 3 (4): e121. doi:10.1371/journal.pbio.0030121. PMC 1069646. PMID 15780005. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
  14. ^ Dunning Hotopp, J.C, Clark ME, Oliveira DC, Foster JM, Fischer P, Torres MC, Giebel JD, Kumar N, Ishmael N, Wang S, Ingram J, Nene RV, Shepard J, Tomkins J, Richards S, Spiro DJ, Ghedin E, Slatko BE, Tettelin H, Werren J.H. (2007). "Widespread Lateral Gene Transfer from Intracellular Bacteria to Multicellular Eukaryotes". Science. 317 (5845): 1753–1756. doi:10.1126/science.1142490. PMID 17761848.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. ^ Whitworth, TL; Dawson, RD; Magalon, H; Baudry, E (2007). "DNA barcoding cannot reliably identify species of the blowfly genus Protocalliphora (Diptera: Calliphoridae)". Proceedings of the Royal Society B. 274: 1731–1739. doi:10.1098/rspb.2007.0062. PMC 2493573.
  16. ^ Johnstone, RA; Hurst, GDD (1996). "Maternally inherited male-killing microorganisms may confound interpretation of mitochondrial DNA variability". Biological Journal of the Linnean Society. 58 (4): 453–470. doi:10.1111/j.1095-8312.1996.tb01446.x.
  17. ^ Teixeira, Luís; Ferreira, Álvaro; Ashburner, Michael (2008). "The Bacterial Symbiont Wolbachia Induces Resistance to RNA Viral Infections in Drosophila melanogaster". PLoS Biol. 6 (12): e1000002. doi:10.1371/journal.pbio.1000002. PMC 2605931. PMID 19222304.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  18. ^ Hoerauf A, Mand S, Fischer K; et al. (2003). "Doxycycline as a novel strategy against bancroftian filariasis-depletion of Wolbachia endosymbionts from Wuchereria bancrofti and stop of microfilaria production". Med. Microbiol. Immunol. 192 (4): 211–6. doi:10.1007/s00430-002-0174-6. PMID 12684759. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  19. ^ Taylor, MJ; Makunde, WH; McGarry, HF; Turner, JD; Mand, S; Hoerauf, A (2005). "Macrofilaricidal activity after doxycycline treatment of Wuchereria bancrofti: a double-blind, randomised placebo-controlled trial". Lancet. 365 (9477): 2116–21. doi:10.1016/S0140-6736(05)66591-9. PMID 15964448.
  20. ^ Xi, Zhiyong; Dean, Jeffry L.; Khoo, Cynthia; Dobson, Stephen. L. (2005). "Generation of a novel Wolbachia infection in Aedes albopictus (Asian tiger mosquito) via embryonic microinjection". Insect Biochemistry and Molecular Biology. 35: 903–910. doi:10.1016/j.ibmb.2005.03.015. PMC 1410910. PMID 15944085.
  21. ^ Moreira LA, Iturbe-Ormaetxe I, Jeffery JA, Lu G, Pyke AT, Hedges LM, Rocha BC, Hall-Mendelin S, Day A, Riegler M, Hugo LE, Johnson KN, Kay BH, McGraw EA, van den Hurk AF, Ryan PA, O'Neill SL (2009) A Wolbachia symbiont in Aedes aegypti limits infection with dengue, chikungunya, and Plasmodium Cell 139(7):1268-1278
  22. ^ McMeniman, Conor J.; Lane, Roxanna V.; Cass, Bodil N.; Fong, Amy W.C.; Sidhu, Manpreet; Wang, Yu-Feng; O'Neill, Scott L. (2009). "Stable Introduction of a Life-Shortening Wolbachia Infection into the Mosquito Aedes aegypti". Science. 323: 141. doi:10.1126/science.1165326. PMID 19119237.
  23. ^ "'Bug' could combat dengue fever". BBC NEWS. British Broadcasting Corporation. 2 January 2009.

Further reading

Retrieved from "https://en.wikipedia.org/w/index.php?title=Wolbachia&oldid=341685087"