Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Genome degeneration affects both extracellular and intracellular bacterial endosymbionts. | BioMed Central Journal of Biology Minireview Genome degeneration affects both extracellular and intracellular bacterial endosymbionts Heike Feldhaar and Roy Gross1 Addresses Lehrstuhl fur Verhaltensphysiologie Barbarastrafie 11 Universitat Osnabruck D-49076 Osnabruck Germany. tLehrstuhl fur Mikrobiologie Biozentrum Am Hubland Universitat Wurzburg D-97074 Wurzburg Germany. Correspondence Roy Gross. Email roy@ Published 6 April 2009 Journal of Biology 2009 8 31 doi jbiol129 The electronic version of this article is the complete one and can be found online at http content 8 3 31 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 beewolves digger wasp which harbor antibiotic-producing actinomycetes .
