| cytology of terminally differentiated epulopiscium mother cells. | epulopiscium sp. type b, a member of the firmicutes, is a large (up to 300 microm), cigar-shaped bacterial symbiont of surgeonfish that propagates itself by forming multiple intracellular offspring. this unusual form of reproduction is an apparent modification of a developmental program used by some firmicutes to produce an endospore. at the onset of offspring formation, the epulopiscium cell divides at both poles. the polar cells are engulfed by the larger mother cell and grow within the mother ... | 2009 | 19196050 |
| extreme polyploidy in a large bacterium. | cells rely on diffusion to move metabolites and biomolecules. diffusion is highly efficient but only over short distances. although eukaryotic cells have broken free of diffusion-dictated constraints on cell size, most bacteria and archaea are forced to remain small. exceptions to this rule are found among the bacterial symbionts of surgeonfish; epulopiscium spp. are cigar-shaped cells that reach lengths in excess of 600 mum. a large epulopiscium contains thousands of times more dna than a bacte ... | 2008 | 18445653 |
| food vacuole contents in the ciliate, balantidium jocularum (balantididae), a symbiont in the intestine of the surgeonfish, naso tonganus (acanthuridae). | during the past 16 years, the ciliate balantidium jocularum has been collected from the intestines of many specimens of its fish host, naso tonganus, all collected from the great barrier reef near lizard island, australia. ciliates for this study of food consumption were isolated in 1988, 1989, 2003, and 2005. nineteen specimens of b. jocularum were examined in the transmission electron microscope to determine the contents of both food vacuoles and a putative discharging cytoproct vacuole. food ... | 2006 | 16872294 |
| export pumps in epulopiscium fishelsoni, the symbiotic giant gut bacterium in acanthurus nigrofuscus. | activity of the potential antixenobiotic efflux pumps of epulopiscium fishelsoni (epulos), the symbiotic giant gut bacterium of the algivorous surgeonfish acanthurus nigrofuscus, was studied in vivo using various specific substrates and microfluorometry. kinetic and inhibitor analyses revealed the following vital efflux activities: (1) verapamil-sensitive efflux of amphiphilic cationic compounds rhodamine b, hoechst 33342, and ethidium bromide; (2) verapamil-sensitive efflux of hydrophobic neutr ... | 2006 | 16534627 |
| nocturnal production of endospores in natural populations of epulopiscium-like surgeonfish symbionts. | prior studies have described a morphologically diverse group of intestinal microorganisms associated with surgeonfish. despite their diversity of form, 16s rrna gene surveys and fluorescent in situ hybridizations indicate that these bacteria are low-g+c gram-positive bacteria related to epulopiscium spp. many of these bacteria exhibit an unusual mode of reproduction, developing multiple offspring intracellularly. previous reports have suggested that some epulopiscium-like symbionts produce dorma ... | 2005 | 16237029 |
| initiation of intracellular offspring in epulopiscium. | epulopiscium spp. are the largest heterotrophic bacteria yet described. a distinguishing feature of the epulopiscium group is their viviparous production of multiple, internal offspring as a means of cellular reproduction. based on their phylogenetic position, among low g + c gram-positive endospore-forming bacteria, and the remarkable morphological similarity between developing endospores and epulopiscium offspring, we hypothesized that intracellular offspring production in epulopiscium evolved ... | 2004 | 14731282 |
| big bacteria. | a small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. the biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 microm wide nanobacteria to the largest cells of the colorless sulfur bacteria, thiomargarita namibiensis, with a diameter of 750 microm. all bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. only the fastest and largest swi ... | 2001 | 11544351 |
| gigantism in a bacterium, epulopiscium fishelsoni, correlates with complex patterns in arrangement, quantity, and segregation of dna. | epulopiscium fishelsoni, gut symbiont of the brown surgeonfish (acanthurus nigrofuscus) in the red sea, attains a larger size than any other eubacterium, varies 10- to 20-fold in length (and >2, 000-fold in volume), and undergoes a complex daily life cycle. in early morning, nucleoids contain highly condensed dna in elongate, chromosome-like structures which are physically separated from the general cytoplasm. cell division involves production of two (rarely three) nucleoids within a cell, depos ... | 1998 | 9791108 |
| nucleoids and coated vesicles of "epulopiscium" spp | we describe here aspects of the anatomy of two "epulopiscium" morphotypes, unusually large bacteria that are not yet cultured and that reproduce by the internal generation of two or more vegetative daughter cells. two morphotypes, a and b, which are enteric symbionts of several species of herbivorous surgeonfish (acanthuridae), were collected around the great barrier reef of australia, preserved there, and later stained for light microscopy. some samples were examined by electron microscopy. in ... | 1998 | 9732436 |
| propagation by sporulation in the guinea pig symbiont metabacterium polyspora. | the gram-positive bacterium metabacterium polyspora is an uncultivated symbiont of the guinea pig gastrointestinal tract. here we present evidence that in m. polyspora vegetative cell division has taken on a minor, and apparently dispensable, role in propagation. instead, this unusual bacterium has evolved the capacity to produce progeny in the form of multiple endospores. endospore formation is coordinated with transit of the bacterium through the gastrointestinal tract of the guinea pig. for t ... | 1998 | 9707627 |
| phylogenetic analysis of metabacterium polyspora: clues to the evolutionary origin of daughter cell production in epulopiscium species, the largest bacteria. | it is rare that there are molecular clues to the evolutionary origin of developmental traits. we have encountered an evolutionary juxtaposition that may explain the origin of the unique replicative morphology of epulopiscium spp., the largest known bacteria, which reproduce by the internal production of multiple live offspring. we report here a 16s rrna-based phylogenetic analysis of metabacterium polyspora, a multiple-endospore-forming, uncultivated inhabitant of guinea pig cecum. cells of m. p ... | 1996 | 8631724 |
| the largest bacterium. | the large, morphologically peculiar microorganism epulopiscium fishelsoni inhabits the intestinal tract of acanthurus nigrofuscus, a brown surgeonfish (family acanthuridae) from the red sea. similar microorganisms have been found in surgeonfish species from the great barrier reef. 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 unclear. initial ... | 1993 | 8459849 |
| an unusual symbiont from the gut of surgeonfishes may be the largest known prokaryote. | symbionts first reported from the gut of a red sea surgeonfish, acanthurus nigrofuscus (family acanthuridae), were subsequently described as epulopiscium fishelsoni. the taxonomic position of this very large (up to 576 microns in length) microorganism has previously been designated in the literature as either uncertain or eukaryotic. we suggest that similar symbionts from great barrier reef surgeonfish may be prokaryotes, which together with e. fishelsoni from the red sea may represent the large ... | 1991 | 1885516 |
| the spoiie homolog of epulopiscium sp. type b is expressed early in intracellular offspring development. | epulopiscium sp. type b is an enormous intestinal symbiont of the surgeonfish naso tonganus. intracellular offspring production in epulopiscium shares features with endospore formation. here, we characterize the spoiie homolog in epulopiscium. the timing of spoiie gene expression and presence of interacting partners suggest that the activation of ¤â(f) occurs early in epulopiscium offspring development. | 2011 | 21398534 |