Transcriptional regulation of fatty acid cis–trans isomerization in the solvent‐tolerant soil bacterium, Pseudomonas putida F1

Abstract

Summary One key to the success of Pseudomonas spp. is their ability to reside in hostile environments. Pseudomonas spp. possess a cis–trans isomerase (Cti) an enzyme that converts the cis‐unsaturated fatty acids (FAs) of the membrane lipids to their trans‐isomers to rigidify the membrane and thereby resist stresses. Whereas the posttranslational Cti regulation has been previously reported, transcriptional cti regulation remains to be studied in more details. Here, we have studied cti transcriptional regulation in the solvent‐tolerant strain Pseudomonas putida F1. Two cti transcriptional start sites (cti‐279 and cti‐77) were identified with cti‐279 transcript being dominant. Expression of cti was found to increase with temperature increase, addition of the organic solvent, octanol and in the stationary growth phase. We found that cti expression was repressed by the cyclic‐AMP receptor protein (Crp) and repression required the cyclic‐AMP ligand of Crp. Production of trans‐unsaturated FAs was found to decrease after 24 h of growth. Although this decrease was accompanied by an increase in cyclopropane FA content, this was not at the expense of trans‐unsaturated FAs demonstrating the absence of competition between Cti and Cfa in FA modification.

The bacterial protective armor against stress: The cis-trans isomerase of unsaturated fatty acids, a cytochrome-c type enzyme

“…Several studies on Pseudomonas spp. to define the transcriptional start site (TSS) have been performed [22,23,44,59], and two TSS of cti were found located at positions -77 and -279 upstream of the translation start site (+1) in P. putida F1 [56]. Similar data were reported for P. putida DOT-T1E…”

“…The cti gene has been isolated from six species of Pseudomonas, namely P. putida P8, P. putida DOT-T1E, Pseudomonas sp. Lz4W (P. syringae Lz4w), P. putida KT2440, P. aeruginosa PAO1 and P. putida F1 [22,23,44,[56][57][58].…”

A cryptic long-chain 3-ketoacyl-ACP synthase in the Pseudomonas putida F1 unsaturated fatty acid synthesis pathway

“…The upstream 200 bp regions of Pput_2425 and fabF2 were fused to a promoter-less lacZ of the pSRK-lacZ expression vector (25), to allow detection of possible promoters. The P Pput_2425 fusion plasmids were transferred into the wild type strain, the ∆Pput_2425 strain plus the ∆fabB suppressor strains and -galactosidase activity was measured.…”

Diclofenac Degradation—Enzymes, Genetic Background and Cellular Alterations Triggered in Diclofenac-Metabolizing Strain Pseudomonas moorei KB4

“…Authors hypothesized that due to those changes, strain is able to deal with destabilization of the inner and outer membrane. Moreover, decreased amounts of phosphatidylethanolamine with prolonged incubation time, and increased amounts of phospholipids having three or four acyls i.e., acyl-phosphatidylglycerol and cardiolipin with the prolonged time of cultivation, were observed [ 15 , 51 , 55 ].…”

“…Bacteria from the genus Pseudomonas are widely known as able to reside in hostile environments since they constitute the indigenous microflora of various contaminated areas i.e., soil, sludge, water bodies and wastewater. The ecological success of pseudomonads can be attributed to great metabolic versatility, effective detoxifying and adapting mechanisms based on the high oxidoreductase activities, adjusting the membranes fluidity or extensive transport, and secretion systems [ 15 ].…”