Megaplasmids in Gram-negative, moderately halophilic bacteria.
We have discovered that many Halomonas species harbour large extrachromosomal DNA elements. Using currently available protocols it is technically very difficult to identify large plasmids in bacteria, and even more so when they are coated in mucous polysaccharide. We used culture conditions suitable for both halophilic and halophilic exopolysaccharide-producing bacteria and applied a modified gel electrophoresis method to locate and visualise the megaplasmids. Almost all the species of Halomonas studied harbour two plasmids of about 70 kb and 600 kb and some species carry other smaller extrachromosomal DNA elements. The common presence of these megaplasmids may well be related to the survival strategies of the bacteria in their special surroundings.
Argandoña
Montserrat
M
Departamento de Microbiologi;a, Facultad de Farmacia, Campus Universitario de Cartuja s/n, 18071, Granada, Spain. admoral@ugr.es
Martínez-Checa
Fernando
F
Llamas
Inmaculada
I
Quesada
Emilia
E
del Moral
Ana
A
D004269:DNA, Bacterial / Q000032:analysis*; D004587:Electrophoresis, Agar Gel; D016680:Genome, Bacterial; D016946:Gram-Negative Aerobic Rods and Cocci / Q000235:genetics; D020632:Halomonas / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics* / Q000302:isolation & purification
D004269:DNA, Bacterial