Open AccessA physical map of the megaplasmid pHG1, one of three genomic replicons in Ralstonia eutropha H16
Author(s) -
Schwartz Edward,
Friedrich Bärbel
Publication year - 2001
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2001.tb10759.x
Subject(s) - ralstonia , replicon , biology , genetics , genome , plasmid , genomic dna , gene , microbiology and biotechnology
We have used pulsed field gel electrophoresis and megabase DNA techniques to investigate the basic genomic organization of Ralstonia eutropha H16, and to construct a physical map of its indigenous megaplasmid pHG1. This Gram‐negative, soil‐dwelling bacterium is a facultative chemolithoautotroph and a denitrifier. In the absence of organic substrates it can grow on H 2 as its sole energy source and CO 2 as its sole source of carbon. Under anaerobic conditions it can utilize nitrate as a terminal electron acceptor, whereby dinitrogen is released. Essential genetic determinants of the enzyme systems responsible for these metabolic processes are linked to the 0.44‐Mb conjugative megaplasmid pHG1. Aside from pHG1, the genome of R. eutropha H16 is comprised of two circular chromosomes measuring 4.1 and 2.9 Mb, adding up to a total genome size of 7.1 Mb. An estimated five copies of rDNA are distributed on the two chromosomes. A macrorestriction map of pHG1 was derived for the endonucleases Dra I and Xba I. Hybridization studies showed that genes for anaerobic metabolism are located on all three genomic replicons.