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Epulopiscium fishelsoni
Introduction
• Discovered in 1985, in the gut of surgeonfish
• Belong to the low G-C Gram-positive bacteria
Clostridium
• Cigar-shaped and tan in colour
Characteristics
• Very large : ~600um in length, Normal E. coli is
~1um
• 2000-million-folder larger in volume. Its cell wall
contains many folds in order to increase surface area
• Can contain 200,000 copies of the
genome
Why so large, so many?
• Deters predation
• Extravagant collection of genomes may be a way for it
to reap the benefits of size without cause starvation
• Ramps up the rate at which Epulopiscium can
produce RNA and protein from its genes
Reproduction
Reproduces exclusively through an unusual form of
sporulation: 1-12 daughter cells are grown inside of
the parent cell, until the cell eventually lyses and
the new bacteria
burst through
the cell wall.
Symbiosis
• Unable to culture it in vitro
• Due to the daily cycle of the E. fishelsoni, it affects
the pH of the surgeonfish's gut fluids differently
during the day and night, suggesting that cyclic
metabolic changes occur within the bacterium.
• hp://microbewiki.kenyon.edu/index.php/Epulopisc
ium
Other interesting bugs
• Buchnera aphidicola, the old record
keeper in term of number of genome
copy
• Thiomargarita namibiensis: the largest
bacterium ~800um, found in 1999
• A type of giant bacteria living in the
eastern South Pacific was just
discovered: can grow several cm long