TY - JOUR
T1 - Cadmium effects on transcriptional expression of rhlB/rhlC genes and congener distribution of monorhamnolipid and dirhamnolipid in Pseudomonas aeruginosa IGB83
AU - Neilson, Julia W.
AU - Zhang, Lin
AU - Veres-Schalnat, Tracey A.
AU - Chandler, Kevin B.
AU - Neilson, Charlotte H.
AU - Crispin, Jennifer D.
AU - Pemberton, Jeanne E.
AU - Maier, Raina M.
N1 - Funding Information:
Acknowledgments This research was supported by Grant CHE 071-4245 from the US National Science Foundation Collaborative Research in Chemistry program.
PY - 2010/10
Y1 - 2010/10
N2 - While variable production of the biosurfactant, rhamnolipid, by Pseudomonas aeruginosa has been shown to be dependent on growth conditions, no research has evaluated potential relationships between rhamnolipid production and the presence of heavy metals. The current investigation evaluates the influence of Cd2+ on rhamnolipid synthesis. Cultures grown in the presence of 0.45 and 0.89 mM Cd2+ were monitored for rhlB/rhlC expression, rhamnolipid yield, and the ratio of monorhamnolipid (RL1) and dirhamnolipid (RL2) produced. Results show a Cdinduced enhancement of rhlB expression in mid-stationary phase (53 h). In addition, sustained production of rhamnolipid through late stationary growth phase (96 h) was observed for Cd-amended cultures, unlike Cd-free control cultures that ceased rhamnolipid production by midstationary growth phase. Most significant was an observed increase in the ratio of RL2 to RL1 congeners produced by cultures grown in the presence of Cd2+. Previous results have shown that the complexation constant for RL2-Cd is several orders of magnitude larger than that of RL1-Cd thus the preferential production of RL2 in the presence of Cd2+ impacts its bioavailability and toxicity both for the cell and in the surrounding environment.
AB - While variable production of the biosurfactant, rhamnolipid, by Pseudomonas aeruginosa has been shown to be dependent on growth conditions, no research has evaluated potential relationships between rhamnolipid production and the presence of heavy metals. The current investigation evaluates the influence of Cd2+ on rhamnolipid synthesis. Cultures grown in the presence of 0.45 and 0.89 mM Cd2+ were monitored for rhlB/rhlC expression, rhamnolipid yield, and the ratio of monorhamnolipid (RL1) and dirhamnolipid (RL2) produced. Results show a Cdinduced enhancement of rhlB expression in mid-stationary phase (53 h). In addition, sustained production of rhamnolipid through late stationary growth phase (96 h) was observed for Cd-amended cultures, unlike Cd-free control cultures that ceased rhamnolipid production by midstationary growth phase. Most significant was an observed increase in the ratio of RL2 to RL1 congeners produced by cultures grown in the presence of Cd2+. Previous results have shown that the complexation constant for RL2-Cd is several orders of magnitude larger than that of RL1-Cd thus the preferential production of RL2 in the presence of Cd2+ impacts its bioavailability and toxicity both for the cell and in the surrounding environment.
KW - Biosurfactant
KW - Cadmium
KW - Pseudomonas aeruginosa
KW - Rhamnolipid congeners
KW - RhlB expression
KW - RhlC expression
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U2 - 10.1007/s00253-010-2808-8
DO - 10.1007/s00253-010-2808-8
M3 - Article
C2 - 20706835
AN - SCOPUS:79952109591
SN - 0175-7598
VL - 88
SP - 953
EP - 963
JO - Applied Microbiology and Biotechnology
JF - Applied Microbiology and Biotechnology
IS - 4
ER -