THE large, morphologically peculiar microorganism Epulopiscium fishelsoni1,2 inhabits the intestinal tract of Acanthurus nigrofuscus, a brown surgeon fish (family Acanthuridae) from the Red Sea. Similar microorganisms have been found in surgeonfish species from the Great Barrier Reef3. As these microorganisms have only been seen in surgeonfish and no free-living forms have been found, they are considered to be specific symbionts of surgeonfish, although the nature of the symbiosis is unclear1–4. Initial reports considered them to be eukaryotic protists, based primarily on their size1–4, with individuals being larger than 600 μm by 80 μm. But their cellular morphology in the electron microscope is more like that of bacterial than eukaryotic cells1,2,54. To resolve the nature of these symbionts, we have isolated the genes encoding the small subunit ribosomal RNA from two morphotypes and used them in a phylogenetic analysis. In situ hybridization with oligonucleotide probes based on the cloned rRNA sequences confirmed the source of the rRNA genes. Our results identify the symbionts as members of the low-(G + C) Gram-positive group of bacteria. They are therefore the largest bacteria to be described so far.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Fishelsen, L. Montgomery, W. L. & Myrberg, A. A. Jr Science 229, 49–51 (1985).
Montgomery, W. L. & Pollak, P. E. J. Protozool. 35, 565–569 (1988).
Clements, K. D., Sutton, D. C. & Choat, J. H. Mar. Biol. 102, 403–412 (1989).
Montgomery, W. L. & Pollak, P. E. Mar. Ecol. Prog. Ser. 44, 7–13 (1988).
Clements, K. D. & Bullivant, S. J. Bact. 173, 5359–5362 (1991).
Saiki, R. K. et al. Science 239, 487–491 (1988).
Olsen, G. J. et al. Nucleic Acids Res. 20, 2199–2200 (1992).
Olsen, G. J. Meth. Enzym. 164, 793–812 (1988).
Woese, C. R. Microbiol. Rev. 51, 221–271 (1987).
Felsenstein, J. Evolution 37, 783–791 (1985).
DeLong, E. F., Wickham, G. S. & Pace, N. R. Science 243, 1360–1363 (1989).
Woese, C. R., Kandler, O. & Wheelis, M. L. Proc. natn. Acad. Sci. U.S.A. 87, 4576–4579 (1990).
Blakemore, R. P. & Canale-Parola, E. Arch. Mikrobiol. 89, 273–289 (1973).
Delaporte, B. Ann. Inst. Pasteur, Paris 107, 246–262 (1964).
Starr, M. P. & Schmidt, J. M. in The Prokaryotes (eds Starr, M. P., Stolp, H. Trüper, H. G., Balows, A. & Schlegel, H. G.) 3–42 (Springer, New York, 1981).
Jannasch, H. W., Nelson, D. C. & Wirsen, C. O. Nature 342, 834–836 (1989).
Ward, D. M., Bateson, M. M., Weller, R. & Ruff-Roberts, A. L. in Advances in Microbial Ecology (ed. Marshall, K. C.) Vol. 12 219–286 (Plenum, New York, 1992).
Sambrook, J., Fritsch, E. F. & Maniatis, T. Molecular Cloning: A Laboratory Manual 2nd edn (Cold Spring Harbor Laboratory, New York, 1989).
Biggin, M. D., Gibson, T. J. & Hong, G. F. Proc. natn. Acad. Sci. U.S.A. 80, 3963–3965 (1983).
About this article
Recombination contributes to population diversification in the polyploid intestinal symbiont Epulopiscium sp. type B
The ISME Journal (2019)
Coral Reefs (2013)
The genomic basis for the evolution of a novel form of cellular reproduction in the bacterium Epulopiscium
BMC Genomics (2012)