Paper: Genome degeneration affects both extracellular and intracellular bacterial endosymbionts

Genome degeneration affects both extracellular and intracellular bacterial
endosymbionts
Heike Feldhaar 1 and Roy Gross 2

1 Lehrstuhl für Verhaltensphysiologie, Barbarastraß 11, Universität
Osnabrück, D-49076 Osnabrück, Germany

2 Lehrstuhl für Mikrobiologie, Biozentrum, Am Hubland, Universität Würzburg,
D-97074 Würzburg, Germany

author email corresponding author email

Journal of Biology 2009, 8:31doi:10.1186/jbiol129

The electronic version of this article is the complete one and can be found
online at: http://jbiol.com/content/8/3/31

Published: 6 April 2009

© 2009 BioMed Central Ltd

Abstract
The obligate intracellular bacterial endosymbionts of insects are a paradigm
for reductive genome evolution. A study published recently in BMC Biology
demonstrates that similar evolutionary forces shaping genome structure may
also apply to extracellular endosymbionts.

The expanding universe of bacterial insect symbionts
Insects are among the most successful animal groups in terrestrial
ecosystems in terms of species richness and abundance. Symbiotic bacteria
have a large part to play in this evolutionary success, often by
contributing to host nutrition or defense against pathogens and predators.
The bacterial companions may be facultative (secondary symbionts) or
obligate (primary symbionts) for the host (Table 1). Symbionts can be found
on the outer surface of the animals (ectosymbionts), as in leaf-cutter ants,
which carry antibiotic-producing actinomycetes on the thorax that help to
protect the cultivated fungus gardens [1]. Other symbionts live in various
locations within the animals (endosymbionts), for example within the gut,
such as the hindgut-inhabiting community required for wood digestion in
termites [2], or the midgut endosymbionts of stinkbugs [3,4]. Moreover,
endosymbionts can be found in various types of organs, such as the antennal
glands of female bee-wolves (digger wasp), which harbor antibiotic-producing
actinomycetes required to protect the eggs from fungal infestation [5]
(Figure 1).

Source: Journal of Biology [Free Paper]
http://jbiol.com/content/8/3/31

Comment:
Mitochondria are thought to have started out as endo-symbionts...apparently
they liked the party and stayed on??

Posted by
Robert Karl Stonjek


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