Symbiont, intracellular

P. Baumann, L. Baumann, C.-Y. Lai, and D. Rouhbakhsh, Genetics, physiology and evolutionary relationships of the genus Buchnera intracellular symbionts of aphids, Annii. Rev. Microbiol. 49 55 (1995). 

Marti, O.G., Rogers, C.E. and Styer, E.L. (1995) Report on intracellular bacterial symbiont in Noctuidonema guayanense, an ectoparasitic nematode of Spodoptera frugiperda. Journal of Invertebrate Pathology 66, 94-96. 

Masui, S., Sasaki, T. and Ishikawa, H. (1997) groE-homologous operon of Wolbachia, an intracellular symbiont of arthropod a new approach to their phylogeny. Zoological Science 14, 701-706. 

Baumann, P., Baumann, L., Lai, C.Y., Rouhbakhsh, D., Moran, N.A. and Clark, M.A. (1995) Genetics, physiology, and evolutionary relationships of the genus Buchnercv. intracellular symbionts of aphids. Annual Review of Microbiology 49, 55-94. 

In addition, sponges harbor symbiotic intracellular microorganisms which may or may not be obligate symbionts and required for production of the desired metabolites. Maintenance of sponge cell cultures may require the use of antibiotics however, use of antibiotics may be harmful to the sponge cells115 and may alter the biosynthesis of the desired metabolite. 

Law R, Hutson V (1992) Intracellular symbionts and the evolution of uniparental cytoplasmic inheritance. Proc Roy Soc Lond B Biol Sci 248 69-77 Lill R, Mfihlenhoff U (2005) Iron-sulfur-protein biogenesis in eukaryotes. Trends Biochem Sci 30 133-141... 

Paul Portier (1866-1962), working at the Institut Oceanographique de Monaco, was the first to write explicitly about mitochondria as symbionts. In his book Les Symbiotes (p. viii in Portier 1918 ), he developed an elaborate theory of symbiosis as a fundamental aspect of life when he argued that mitochondria were symbionts, transformed over eons by their intracellular existence ... 

Sulfur metabolism of insects. IV. Conversion of inorganic sulfate to organic sulfur compounds in cockroaches. Role of intracellular symbionts. Con-tribs. Boyce Thompson Inst., 20, 317 (1960). With S. M. Henry. 

Mitochondria were first observed by R. Altmann in 1890. He named them bioblasts, because he speculated that they and chloroplasts (the green chlorophyll-containing organelles of plants) might be intracellular symbionts that arose from bacteria and algae, respectively. This idea lay in disrepute until the recent discovery of mitochondrial nucleic acids. 

In fact, bacteria do not have mitochondria, but some types do have membranous intrusions into the cytoplasm called mesosomes. These are similar in function to the inner membrane of mitochondria (Chap. 14). The reason mitochondria are distinct from other membranous structures in higher cells is posssibly due to their evolutionary origin as intracellular symbionts and to the fact that the spatial separation of functions leads to more advantageous (in terms of natural selection) control of the various metabolic processes. 

Carpenter, E. J., andjanson, S. (2000). Intracellular cyanobacteria symbionts in the marine diatom Climacodium frauenfeldianum (Bacihariophyceae). /. Phycol. 36, 540—544. 

One general way to distinguish between various forms of symbiosis is to identify the location of the attachment of the symbiont to the host. Symbionts that live on the host surface, including internal surfaces like the digestive tube, participate in ectosymbiosis (Greek eictoc = outside). If a symbiont is localized within the tissues of the host, the association is termed "endosymbiosis" (Greek evSov = within). Endosymbionts can be found either in the extracellular space or intracellularly. 

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