Wigglesworthia glossinidia

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Wigglesworthia glossinidia brevipalpis

Characteristics of W. glossinidia

The phylogenetic classification of W. glossinidia is:

Domain: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Wigglesworthia
Species: Wigglesworthia glossinidia

W. glossinidia is a gram-negative, rod shaped Enterobacterium that resides in the gut of the tsetse fly (Glossinidae). Its genome has been sequenced at 697,724 base pairs [1].

Characteristics of the tsetse fly

The tsetse fly (Genus: Glossina) is a blood-sucking insect found in Africa that is known to carry protozoan parasites called trypanosomes which cause African Trypanosomosis, or African sleeping sickness, a disease which affects humans and livestock and is fatal if left untreated. The disease is devastating to the local economies affected, which include some of the poorest in the world. [2]

Host-Symbiont Interaction

W. glossinidia resides in the intestines and ovary tissues of the tsetse fly, in organelles known as mycetomes [3]. W. glossinidia has an obligate mutualist relationship with the tsetse fly, providing it with vitamins and nutrients which are vital to the fly's growth and ability to reproduce. It was found that removal of W. glossinidia from a female host's system resulted in total sterility for the fly [4].

Molecular Insights into the Symbiosis

Little is known about "W. glossinidia's" metabolic products on account of it being unable to be cultivated "in vitro". The tsetse fly's diet of blood is vitamin deficient and experiments have shown that in individuals without "W. glossinidia", B-vitamin supplements restored some of the viability lost by the removal of "W. glossinidia". This indicates that "W. glossinidia" plays an important role in the metabolism of B-vitamins in its host [5].

Ecological and Evolutionary Aspects

Despite "W. glossinidia's" role as an obligate mutualist, its genome contains genes for a flagellum. This is strange because, besides it being an organelle generally associated with free-living microbes, scientists have never observed "W. glossinidia" with flagella. The presence of these genes could indicate that the symbiosis between "W. glossinidia" and the tsetse fly is a fairly recent one. Alternately, as the method by which "W. glossinidia" is transferred from mother to offspring is unknown, it could be that a certain stage of "W. glossinidia's" development includes a flagellum for transfer to larval cells [6].

Recent Discoveries

Scientists are currently looking into ways that tsetse fly populations could be controlled or eliminated by taking advantage of its reproductive reliance on "W. glossinidia" [7].

References

1. Akman, L., Yamashita, A., Watanabe, H., Oshima, K., Shiba, T., Hattori, M., and Aksoy, S. “Genome sequence of the endocellular obligate symbiont of tsetse flies, Wigglesworthia glossinidia” Natural Genetics. 2002. Volume 32. p. 402-407. http://www.nature.com/ng/journal/v32/n3/full/ng986.html

2. Aksoy, S. "Wigglesworthia Gen. Nov. and Wigglesworthia Glossinidia Sp. Nov., Taxa Consisting of the Mycetocyte-Associated, Primary Endosymbionts of Tsetse Flies." International Journal Of Systematic And Evolutionary Microbiology 45.4 (1995): 848-51. http://www.nature.com/ng/journal/v32/n3/full/ng986.html

3. "FAO's Animal Production and Health Division." FAO's Animal Production and Health Division. FAO, n.d. Web. 25 Sept. 2012. http://www.fao.org/ag/againfo/programmes/en/paat/home.html

4. "Human African Trypanosomiasis." Who.int. World Health Organization, 2012. Web. 4 Dec. 2012. http://www.who.int/trypanosomiasis_african/vector_control/en/index.html

5. Pais, R., C. Lohs, Y. Wu, J. Wang, and S. Aksoy. "The Obligate Mutualist Wigglesworthia Glossinidia Influences Reproduction, Digestion, and Immunity Processes of Its Host, the Tsetse Fly." Applied and Environmental Microbiology 74.19 (2008): 5965-974.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2565960/

edited by CHruza a student of Rachel Larsen and Kit Poligano at UCSD and William Gillespie, student of Grace Lim-Fong