Epulopiscium fishelsoni - Academic lab pages
Transcription
Epulopiscium fishelsoni - Academic lab pages
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. • hp://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