Metabolic Interdependence of Obligate Intracellular Bacteria and Their Insect Hosts

Zientz, Evelyn; Dandekar, Thomas; Gross, Roy

doi:10.1128/mmbr.68.4.745-770.2004

Cited by 260 publications

(243 citation statements)

References 140 publications

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“…As a result, a better understanding of the physiological basis of many bacterial endosymbioses, mainly in invertebrates, has been achieved. Here, the crucial nutritional role of endosymbionts in diverse lineages has been unveiled (for reviews see Zientz et al 2004;Baumann 2005;Moya et al 2008). Common features in genome evolution of endosymbiotic bacteria were discovered such as acquisition of an AT-bias and genome reduction (Moya et al 2008).…”

Section: Prokaryotic Endosymbionts In Protists (A) Photosynthetic Endmentioning

confidence: 99%

Endosymbiotic associations within protists

Nowack

Melkonian

2010

Phil. Trans. R. Soc. B

208

168

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The establishment of an endosymbiotic relationship typically seems to be driven through complementation of the host's limited metabolic capabilities by the biochemical versatility of the endosymbiont. The most significant examples of endosymbiosis are represented by the endosymbiotic acquisition of plastids and mitochondria, introducing photosynthesis and respiration to eukaryotes. However, there are numerous other endosymbioses that evolved more recently and repeatedly across the tree of life. Recent advances in genome sequencing technology have led to a better understanding of the physiological basis of many endosymbiotic associations. This review focuses on endosymbionts in protists (unicellular eukaryotes). Selected examples illustrate the incorporation of various new biochemical functions, such as photosynthesis, nitrogen fixation and recycling, and methanogenesis, into protist hosts by prokaryotic endosymbionts. Furthermore, photosynthetic eukaryotic endosymbionts display a great diversity of modes of integration into different protist hosts.In conclusion, endosymbiosis seems to represent a general evolutionary strategy of protists to acquire novel biochemical functions and is thus an important source of genetic innovation.

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Section: Prokaryotic Endosymbionts In Protists (A) Photosynthetic Endmentioning

confidence: 99%

Endosymbiotic associations within protists

Nowack

Melkonian

2010

Phil. Trans. R. Soc. B

208

168

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“…Zientz et al [27] emphasized that facultative or obligate intracellular bacteria can be found throughout the tree of life from protists to plants and animals, and that such biological relationships could have culminated with the stable integration of one cell into another as suggested in the endosymbiont theory [14,16]. In many cases, using lab experiments, it has been shown that mutualistic relationships were obligatory [4,5,10,17,18,24] and thus prevent competitive exclusion.…”

Section: Introductionmentioning

confidence: 99%

Association between competition and obligate mutualism in a chemostat

Hajji

Harmand

Chaker

et al. 2009

Journal of Biological Dynamics

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In this paper, we consider a simple chemostat model involving two obligate mutualistic species feeding on a limiting substrate. Systems of differential equations are proposed as models of this association. A detailed qualitative analysis is carried out. We show the existence of a domain of coexistence, which is a set of initial conditions in which both species survive. We demonstrate, under certain supplementary assumptions, the uniqueness of the stable equilibrium point which corresponds to the coexistence of the two species.

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“…Primary symbionts are typically extremely numerous or packed within discrete organs, facilitating the recovery and sequencing of their genomic DNA without massive host contamination (e.g., refs. [22][23][24][25][26]. However, some symbionts, including H. defensa and other insect secondary symbionts within Enterobacteriaceae, do not occupy specialized organs and reside at low titers within hosts.…”

mentioning

confidence: 99%

The players in a mutualistic symbiosis: Insects, bacteria, viruses, and virulence genes

Moran

Degnan

Santos

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

289

271

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Aphids maintain mutualistic symbioses involving consortia of coinherited organisms. All possess a primary endosymbiont, Buchnera, which compensates for dietary deficiencies; many also contain secondary symbionts, such as Hamiltonella defensa, which confers defense against natural enemies. Genome sequences of uncultivable secondary symbionts have been refractory to analysis due to the difficulties of isolating adequate DNA samples. By amplifying DNA from hemolymph of infected pea aphids, we obtained a set of genomic sequences of H. defensa and an associated bacteriophage. H. defensa harbors two type III secretion systems, related to those that mediate host cell entry by enteric pathogens. The phage, called APSE-2, is a close relative of the previously sequenced APSE-1 but contains intact homologs of the gene encoding cytolethal distending toxin (cdtB), which interrupts the eukaryotic cell cycle and which is known from a variety of mammalian pathogens. The cdtB homolog is highly expressed, and its genomic position corresponds to that of a homolog of stx (encoding Shiga-toxin) within APSE-1. APSE-2 genomes were consistently abundant in infected pea aphids, and related phages were found in all tested isolates of H. defensa, from numerous insect species. Based on their ubiquity and abundance, these phages appear to be an obligate component of the H. defensa life cycle. We propose that, in these mutualistic symbionts, phage-borne toxin genes provide defense to the aphid host and are a basis for the observed protection against eukaryotic parasites.Acrythosiphon pisum ͉ Hamiltonella defensa ͉ lamboid phage ͉ aphid ͉ Enterobacteriaceae

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Metabolic Interdependence of Obligate Intracellular Bacteria and Their Insect Hosts

Cited by 260 publications

References 140 publications

Endosymbiotic associations within protists

Endosymbiotic associations within protists

Association between competition and obligate mutualism in a chemostat

The players in a mutualistic symbiosis: Insects, bacteria, viruses, and virulence genes

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