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Isolation and characterization of a regulatory gene affecting rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa.
J Bacteriol. 1994 Apr; 176(7):2044-54.JB

Abstract

A mutant strain (65E12) of Pseudomonas aeruginosa that is unable to produce rhamnolipid biosurfactants and lacks rhamnosyltransferase activity was genetically complemented by using a P. aeruginosa PG201 wild-type gene library. A single complementing cosmid was isolated on the basis of surface tension measurements of subcultures of the transconjugants by using a sib selection strategy. The subcloning of the complementing cosmid clone yielded a 2-kb fragment capable of restoring rhamnolipid biosynthesis, rhamnosyltransferase activity, and utilization of hexadecane as a C source in mutant 65E12. The nucleotide sequence of the complementing 2-kb fragment was determined, and a single open reading frame (rhlR) of 723 bp specifying a putative 28-kDa protein (RhlR) was identified. Sequence homologies between the RhlR protein and some regulatory proteins such as LasR of P. aeruginosa, LuxR of Vibrio fischeri, RhiR of Rhizobium leguminosarum, and the putative activator 28-kDa UvrC of Escherichia coli suggest that the RhlR protein is a transcriptional activator. A putative target promoter which is regulated by the RhlR protein has been identified 2.5 kb upstream of the rhlR gene. Multiple plasmid-based rhlR gene copies had a stimulating effect on the growth of the P. aeruginosa wild-type strain in hexadecane-containing minimal medium, on rhamnolipid production, and on the production of pyocyanin chromophores. Disruption of the P. aeruginosa wild-type rhlR locus led to rhamnolipid-deficient mutant strains, thus confirming directly that this gene is necessary for rhamnolipid biosynthesis. Additionally, such PG201::'rhlR' mutant strains lacked elastase activity, indicating that the RhlR protein is a pleiotropic regulator.

Authors+Show Affiliations

Institute for Biotechnology, Swiss Federal Institute of Technology, ETH-Hönggerberg, Zürich.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8144472

Citation

Ochsner, U A., et al. "Isolation and Characterization of a Regulatory Gene Affecting Rhamnolipid Biosurfactant Synthesis in Pseudomonas Aeruginosa." Journal of Bacteriology, vol. 176, no. 7, 1994, pp. 2044-54.
Ochsner UA, Koch AK, Fiechter A, et al. Isolation and characterization of a regulatory gene affecting rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa. J Bacteriol. 1994;176(7):2044-54.
Ochsner, U. A., Koch, A. K., Fiechter, A., & Reiser, J. (1994). Isolation and characterization of a regulatory gene affecting rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa. Journal of Bacteriology, 176(7), 2044-54.
Ochsner UA, et al. Isolation and Characterization of a Regulatory Gene Affecting Rhamnolipid Biosurfactant Synthesis in Pseudomonas Aeruginosa. J Bacteriol. 1994;176(7):2044-54. PubMed PMID: 8144472.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Isolation and characterization of a regulatory gene affecting rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa. AU - Ochsner,U A, AU - Koch,A K, AU - Fiechter,A, AU - Reiser,J, PY - 1994/4/1/pubmed PY - 1994/4/1/medline PY - 1994/4/1/entrez SP - 2044 EP - 54 JF - Journal of bacteriology JO - J. Bacteriol. VL - 176 IS - 7 N2 - A mutant strain (65E12) of Pseudomonas aeruginosa that is unable to produce rhamnolipid biosurfactants and lacks rhamnosyltransferase activity was genetically complemented by using a P. aeruginosa PG201 wild-type gene library. A single complementing cosmid was isolated on the basis of surface tension measurements of subcultures of the transconjugants by using a sib selection strategy. The subcloning of the complementing cosmid clone yielded a 2-kb fragment capable of restoring rhamnolipid biosynthesis, rhamnosyltransferase activity, and utilization of hexadecane as a C source in mutant 65E12. The nucleotide sequence of the complementing 2-kb fragment was determined, and a single open reading frame (rhlR) of 723 bp specifying a putative 28-kDa protein (RhlR) was identified. Sequence homologies between the RhlR protein and some regulatory proteins such as LasR of P. aeruginosa, LuxR of Vibrio fischeri, RhiR of Rhizobium leguminosarum, and the putative activator 28-kDa UvrC of Escherichia coli suggest that the RhlR protein is a transcriptional activator. A putative target promoter which is regulated by the RhlR protein has been identified 2.5 kb upstream of the rhlR gene. Multiple plasmid-based rhlR gene copies had a stimulating effect on the growth of the P. aeruginosa wild-type strain in hexadecane-containing minimal medium, on rhamnolipid production, and on the production of pyocyanin chromophores. Disruption of the P. aeruginosa wild-type rhlR locus led to rhamnolipid-deficient mutant strains, thus confirming directly that this gene is necessary for rhamnolipid biosynthesis. Additionally, such PG201::'rhlR' mutant strains lacked elastase activity, indicating that the RhlR protein is a pleiotropic regulator. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/8144472/Isolation_and_characterization_of_a_regulatory_gene_affecting_rhamnolipid_biosurfactant_synthesis_in_Pseudomonas_aeruginosa_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=8144472 DB - PRIME DP - Unbound Medicine ER -