DNA is preserved and maintains transforming potential after contact with
brines of the deep anoxic hypersaline lakes of the Eastern Mediterranean Sea

Sara Borin, Elena Crotti, Francesca Mapelli, Isabella Tamagnini, Cesare
Corselli and Daniele Daffonchio

Saline Systems 2008, 4:10doi:10.1186/1746-1448-4-10

Published: 5 August 2008

Abstract (provisional)

Background
Extracellular dissolved DNA has been demonstrated to be present in many
terrestrial and aquatic environments, actively secreted, or released by
decaying cells. Free DNA has the genetic potential to be acquired by living
competent cells by horizontal gene transfer mediated by natural
transformation. Aim of this work is to study the persistence of
extracellular DNA and its biological transforming activity in extreme
environments like the deep hypersaline anoxic lakes of the Mediterranean
Sea. The brine lakes are separated from the upper seawater by a steep
chemocline inhabited by stratified prokaryotic networks, where cells sinking
through the depth profile encounter increasing salinity values and osmotic
stress.

Results
Seven strains belonging to different taxonomic groups isolated from the
seawater-brine interface of four hypersaline lakes were grown at medium
salinity and then incubated in the brines. The osmotic...