Evidence of indigenous NAH plasmid of naphthalene degrading Pseudomonas putida PpG7 strain implicated in limonin degradation.
A well characterized naphthalene-degrading strain, Pseudomonas putida PpG7 was observed to utilize limonin, a highly-oxygenated triterpenoid compound as a sole source of carbon and energy. Limonin concentrations evidenced a 64% reduction over 48 h of growth in batch cultures. Attempts were made to acquire a plasmid-less derivative via various methods (viz. Ethidium Bromide, SDS, elevated temperature & mitomycin C), among which the method involving mitomycin C (20 ug/ml) proved successful. Concomitant with the loss of plasmid in P. putida PpG7 strain, the cured derivative was identified as a lim- phenotype. The lim+ phenotype could be conjugally transferred to the cured derivative. Based on the results of curing with mitomycin C, conjugation studies and presence of ndo gene encoding naphthalene 1,2 dioxygenase, it was demonstrated that genes for the limonin utilization were encoded on an 83 kb indigenous transmissible Inc. P9 NAH plasmid in Pseudomonas putida PpG7 strain.
Ghosh
Moushumi
M
Department of Biotechnology and Environmental Sciences, Thapar Institute of Engineering and Technology, Patiala 147004, India. mghosh@tiet.ac.in
Ganguli
Abhijit
A
Mallik
Meenakshi
M
D004269:DNA, Bacterial / Q000235:genetics; D049308:Dioxygenases; D004587:Electrophoresis, Agar Gel / Q000379:methods; D036701:Limonins / Q000378:metabolism*; D050296:Microbial Viability; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009281:Naphthalenes / Q000378:metabolism*; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D016958:Pseudomonas putida / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
D004269:DNA, Bacterial; D036701:Limonins; D009097:Multienzyme Complexes; D009281:Naphthalenes; C031721:naphthalene; D010105:Oxygenases; D049308:Dioxygenases; C038703:naphthalene dioxygenase; C001546:limonin