Wigglesworthia glossinidia

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Wigglesworthia glossinidia brevipalpis

Scientific Classification

Domain: Bacteria Phylum: Proteobacteria Class: Gamma Proteobacteria Order: Enterobacteriales Family: Enterobacteriaceae Genus: Wigglesworthia Species: W. glossinidia brevipalpis Binomial name: Wigglesworthia glossinidia

Description and Significance

Wigglesworthia glossinsdia brevipalpis bears the name of the British entomologist, Sir Vincient Brian Wigglesworth, who first described it. W. glossinidia is a gram-negative bacterium, related to E. coli, which lives in the intestine of the tsetse fly. Wigglesworthia has symbiotically co-evolved with the tsetse fly for millions of years, a classical example of bacterial endosymbiont. Because of this relationship, it has lost a large part of its genome, therefore making it one of the smallest genomes of any living organisms. In order to survive, the tsetse fly depends on the Wigglesworthia to synthesize vital vitamins which it does not get from its diet of blood. Without these key vitamins the W. glossinida produces, the tsetse fly cannot reproduce. Since the tsetse fly spreads African sleeping sickness, Wigglesworthia may be one day used to better control the spread of this deadly sleeping disease.

Genome Structure

Wigglesworthia glossinidia has one of the smallest genomes sequences, estimated to range from 705 to 770-kb based on Pulsed Field Gel Electrophoresis. Its complete sequenced genome is 697,724 base pairs, about one-sixth of that is related to the well known bacterium Escherichia coli. W. glossinidia still contains remnants of a free-living organism, such as genes for motility. Scientists have found genes that synthesize flagella, although never have seen them swim. The Wigglesworthia genome also contains over 60 genes involved in the synthesis of vitamins. The CMR statistics for Wigglesworthia glossinidia brevipalpis are as follows:

Total number of all DNA molecules: 1

Total size of all DNA molecules: 697,724 base pairs

Number of Primary Annotation coding bases: 605,288 bp

Protein encoding genes: 611

Conserved hypothetical genes:13

Hypotetical genes: 1

tRNA genes: 34

rRNA genes: 6

Cell Structure and Metabolism

Scientists have never seen Wigglesworthia swim, and yet they have found remnants of genes that synthesize flagella. Theories suggest that flagella may help Wigglesworthia travel from an adult tsetse fly to its larva. According to Dalke’s article, “Wigglesworthia wiggles into the world of sequenced genomes,” the female tsetse flies fertilizes their offspring in the uterus, W. glossinidia is then transferred from the mother. Another theory is that the flagella facilitate bacteria in motility to or invasion of the larval cells.

Ecology

This bacterium lives inside the gut of the blood sucking tsetse fly which is found only to be in Africa. Wigglesworthia glossinidia with the tsetse flies live in symbiosis.

Pathology

The tsetse fly is a carrier of the African Trypanosomes, the parasite that causes the deadly sleeping sickness. Without Wigglesworthia synthesizing vitamins or nutrients for the tsetse fly, the fly becomes sterile. The inability to fertilize may someday be used to prevent the spread of this disease. By removing the bacteria from tsetse flies, scientists would be capable of stopping the development of the offspring, therefore reducing the populations and disease transmission.

Application and Biotechnology

The “big picture” according to Aksoy in “Genome sequence of the endocellular obligate symbiont of tsetse flies, Wigglesworthia glossinidia,” is to investigate the interactions between the parasite, fly and symbiotic bacteria-including whether the bacteria supply essential nutrients not only to the tsetse flies, but also to the parasite.

Current Research

According to Dalke’s article, Serap Alskoy maintains one of only a few tsetse fly colonies in the world. This female scientist breeds five different species of tsetse flies, with around 5,000 breeding adults at one time. The research team does not work with flies that have parasites that infect humans, claims Dalke. However, they use a sibling species that causes disease in animals.

References

1. Akman, L., Yamashita, A., Watanabe, H., Oshima, K., Shiba, T., Hattori, M., and Aksoy, S. “Natural Genetics. 2002. Volume 32. p. 402-407. http://www.nature.com/ng/journal/v32/n3/full/ng986.html

2. Dalke, Kate. “Wigglesworthia wiggles into the world of sequenced genomes”. Genome News Network. 13 September 2002. http://www.genomenewsnetwork.org/articles/09_02/wiggles.shtml

3. “Wigglesworthia glossinidia brevipalpis”. Wikipedia. 22 March 2007. http://en.wikipedia.org/wiki/wigglesworthia_glossinidia

4. Comprehensive Microbial Resource. “General Information fro Wiggleswoorthia glossinidia breivipalpis”. The Institute for Genome Research. Steptember 27, 2006. http://cmr.tigr.org/tigerscripts/CMR/GenomePAge.cgi?otg=ntwb01

edited by CHruza a student of Rachel Laresen and Kit Poligano at UCSD