title: Genetic transfer by conjugation in the thermophilic green sulfur bacterium Chlorobium tepidum.
abstract: The broad-host-range IncQ group plasmids pDSK519 and pGSS33 were transferred by conjugation from Escherichia coli into the thermophilic green sulfur bacterium Chlorobium tepidum. C. tepidum exconjugants expressed the kanamycin and ampicillin-chloramphenicol resistances encoded by pDSK519 and pGSS33, respectively. Ampicillin resistance was a particularly good marker for selection in C. tepidum. Both pDSK519 and pGSS33 were stably maintained in C. tepidum at temperatures below 42 degrees C and could be transferred between C. tepidum and E. coli without modifications. Conjugation frequencies ranged from 10(-1) to 10(-4) exconjugants per donor cell, and frequencies of 10(-2) to 10(-3) were consistently obtained when ampicillin resistance was used as a selectable marker. Methods for growth of C. tepidum on agar, isolation of plating strains and antibiotic-resistant mutants of wild-type C. tepidum cells, and optimum conditions for conjugation were also investigated.
authors.affiliation: Department of Microbiology, Southern Illinois University, Carbondale 62901-6508, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Wahlund
authors.forename: M T
authors.initials: MT
authors.lastname: Madigan
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000254:growth & development; D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial / Q000235:genetics; D018014:Gene Transfer Techniques; D005819:Genetic Markers; D010788:Photosynthesis / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D012641:Selection, Genetic
chemical_list: D005819:Genetic Markers