Plasmid AZOBR_p1-borne fabG gene for putative 3-oxoacyl-[acyl-carrier protein] reductase is essential for proper assembly and work of the dual flagellar system in the alphaproteobacterium Azospirillum brasilense Sp245

2018 ◽  
Vol 64 (2) ◽  
pp. 107-118 ◽  
Author(s):  
Yulia A. Filip’echeva ◽  
Andrei V. Shelud’ko ◽  
Alexei G. Prilipov ◽  
Gennady L. Burygin ◽  
Elizaveta M. Telesheva ◽  
...  

Azospirillum brasilense can swim and swarm owing to the activity of a constitutive polar flagellum (Fla) and inducible lateral flagella (Laf), respectively. Experimental data on the regulation of the Fla and Laf assembly in azospirilla are scarce. Here, the coding sequence (CDS) AZOBR_p1160043 (fabG1) for a putative 3-oxoacyl-[acyl-carrier protein (ACP)] reductase was found essential for the construction of both types of flagella. In an immotile leaky Fla− Laf− fabG1::Omegon-Km mutant, Sp245.1610, defects in flagellation and motility were fully complemented by expressing the CDS AZOBR_p1160043 from plasmid pRK415. When pRK415 with the cloned CDS AZOBR_p1160045 (fliC) for a putative 65.2 kDa Sp245 Fla flagellin was transferred into the Sp245.1610 cells, the bacteria also became able to assemble a motile single flagellum. Some cells, however, had unusual swimming behavior, probably because of the side location of the organelle. Although the assembly of Laf was not restored in Sp245.1610 (pRK415-p1160045), this strain was somewhat capable of swarming motility. We propose that the putative 3-oxoacyl-[ACP] reductase encoded by the CDS AZOBR_p1160043 plays a role in correct flagellar location in the cell envelope and (or) in flagellar modification(s), which are also required for the inducible construction of Laf and for proper swimming and swarming motility of A. brasilense Sp245.

2021 ◽  
pp. 101434
Author(s):  
Sarah G. Whaley ◽  
Christopher D. Radka ◽  
Chitra Subramanian ◽  
Matthew W. Frank ◽  
Charles O. Rock

2006 ◽  
Vol 188 (24) ◽  
pp. 8376-8384 ◽  
Author(s):  
Fumiko Taguchi ◽  
Yujiro Ogawa ◽  
Kasumi Takeuchi ◽  
Tomoko Suzuki ◽  
Kazuhiro Toyoda ◽  
...  

ABSTRACT Pseudomonas syringae pv. tabaci 6605 possesses a genetic region involved in flagellin glycosylation. This region is composed of three open reading frames: orf1, orf2, and orf3. Our previous study revealed that orf1 and orf2 encode glycosyltransferases; on the other hand, orf3 has no role in posttranslational modification of flagellin. Although the function of Orf3 remained unclear, an orf3 deletion mutant (Δorf3 mutant) had reduced virulence on tobacco plants. Orf3 shows significant homology to a 3-oxoacyl-(acyl carrier protein) synthase III in the fatty acid elongation cycle. The Δorf3 mutant had a significantly reduced ability to form acyl homoserine lactones (AHLs), which are quorum-sensing molecules, suggesting that Orf3 is required for AHL synthesis. In comparison with the wild-type strain, swarming motility, biosurfactant production, and tolerance to H2O2 and antibiotics were enhanced in the Δorf3 mutant. A scanning electron micrograph of inoculated bacteria on the tobacco leaf surface revealed that there is little extracellular polymeric substance matrix surrounding the cells in the Δorf3 mutant. The phenotypes of the Δorf3 mutant and an AHL synthesis (ΔpsyI) mutant were similar, although the mutant-specific characteristics were more extreme in the Δorf3 mutant. The swarming motility of the Δorf3 mutant was greater than that of the ΔpsyI mutant. This was attributed to the synergistic effects of the overproduction of biosurfactants and/or alternative fatty acid metabolism in the Δorf3 mutant. Furthermore, the amounts of iron and biosurfactant seem to be involved in biofilm development under quorum-sensing regulation in P. syringae pv. tabaci 6605.


Author(s):  
Katharigatta N. Venugopala ◽  
Christophe Tratrat ◽  
Melendhran Pillay ◽  
Pran Kishore Deb ◽  
Deepak Chopra ◽  
...  

Background: Tuberculosis remains one of the most deadly infectious diseases worldwide due to the emergence of multi-drug resistance (MDR) and extensively drug resistance (XDR) strains of Mycobacterium tuberculosis (MTB). Materials and Methods: Herein, the screening of a total of eight symmetrical 1,4-dihydropyridine (1,4-DHP) derivatives (4a-4h) was carried out for whole-cell anti-TB activity against the susceptible H37Rv and MDR strains of MTB. Results and Discussion: Most of the compounds exhibited moderate to excellent activity against the susceptible H37Rv. Moreover, the most promising compound 4f (against H37Rv) having para-trifluoromethyl phenyl group at 4-position and bis para-methoxy benzyl ester group at 3- and 5-positions of 1,4-dihydropyridine pharmacophore, exhibited no toxicity, but demonstrated weak activity against MTB strains resistant to isoniazid and rifampicin. In light of the inhibitory profile of the title compounds, enoyl-acyl carrier protein reductase (InhA) appeared to be the appropriate molecular target. Docking study of these derivatives against InhA receptor revealed favorable binding interactions. Further, in silico predicted ADME properties of these compounds 4a-4h were found to be in the acceptable ranges including satisfactory Lipinski’s rule of five, thereby indicating their potential as drug-like molecules. Conclusion: In particular, the 1,4-DHP derivative 4f can be considered as an attractive lead molecule for further exploration and development of more potent anti-TB agents as InhA inhibitors.


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