Characterization of two LuxI/R homologs in Pantoea ananatis LMG 2665T

2016 ◽  
Vol 62 (11) ◽  
pp. 893-903 ◽  
Author(s):  
Siphathele Sibanda ◽  
Jacques Theron ◽  
Divine Y. Shyntum ◽  
Lucy N. Moleleki ◽  
Teresa A. Coutinho
Keyword(s):  
Quorum Sensing ◽  
Genome Sequence ◽  
Biofilm Formation ◽  
Biological Significance ◽  
Bacterial Strains ◽  
Pantoea Ananatis ◽  
Ecological Fitness ◽  
Host Interactions

Quorum sensing (QS) plays an important role in the regulation of bacteria–host interactions and ecological fitness in many bacteria. In this study, 2 luxI/R homologs, namely eanI/eanR and rhlI/rhlR, were identified in the genome sequence of Pantoea ananatis LMG 2665T. To determine a role for these luxI/R homologs in pathogenicity and biofilm formation, mutant bacterial strains lacking either eanI/R or rhlI/R and both of these homologs were generated. The results indicated that both the RhlI/R and EanI/R systems are required for pathogenicity and biofilm formation in strain LMG 2665T. This is the first study to characterize the biological significance of the RhlI/R QS system in P. ananatis.

scholarly journals The Plant Pathogen Pantoea ananatis Produces N-Acylhomoserine Lactone and Causes Center Rot Disease of Onion by Quorum Sensing

2007 ◽  
Vol 189 (22) ◽  
pp. 8333-8338 ◽  
Author(s):  
Tomohiro Morohoshi ◽  
Yuta Nakamura ◽  
Go Yamazaki ◽  
Akio Ishida ◽  
Norihiro Kato ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Receptor Gene ◽  
Homoserine Lactone ◽  
Pantoea Ananatis ◽  
Signal Molecule ◽  
Acylhomoserine Lactone ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Rot Disease

ABSTRACT A number of gram-negative bacteria have a quorum-sensing system and produce N-acyl-l-homoserine lactone (AHL) that they use them as a quorum-sensing signal molecule. Pantoea ananatis is reported as a common colonist of wheat heads at ripening and causes center rot of onion. In this study, we demonstrated that P. ananatis SK-1 produced two AHLs, N-hexanoyl-l-homoserine lactone (C6-HSL) and N-(3-oxohexanoyl)-l-homoserine lactone (3-oxo-C6-HSL). We cloned the AHL-synthase gene (eanI) and AHL-receptor gene (eanR) and revealed that the deduced amino acid sequence of EanI/EanR showed high identity to those of EsaI/EsaR from P. stewartii. EanR repressed the ean box sequence and the addition of AHLs resulted in derepression of ean box. Inactivation of the chromosomal eanI gene in SK-1 caused disruption of exopolysaccharide (EPS) biosynthesis, biofilm formation, and infection of onion leaves, which were recovered by adding exogenous 3-oxo-C6-HSL. These results demonstrated that the quorum-sensing system involved the biosynthesis of EPS, biofilm formation, and infection of onion leaves in P. ananatis SK-1.

scholarly journals Design, Synthesis, and Evaluation of Alkyl-Quinoxalin-2(1H)-One Derivatives as Anti-Quorum Sensing Molecules, Inhibiting Biofilm Formation in Aeromonas caviae Sch3

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3075 ◽  
Author(s):  
René Blöcher ◽  
Ariel Rodarte Ramírez ◽  
Graciela Castro-Escarpulli ◽  
Everardo Curiel-Quesada ◽  
Alicia Reyes-Arellano
Keyword(s):  
Carboxylic Acid ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Alternative Methods ◽  
Resistant Bacteria ◽  
Bacterial Strains ◽  
Design Synthesis ◽  
Bacterial Communication ◽  
Aeromonas Caviae

With the increasing antibiotic resistance of bacterial strains, alternative methods for infection control are in high demand. Quorum sensing (QS) is the bacterial communication system based on small molecules. QS is enables bacterial biofilm formation and pathogenic development. The interruption of QS has become a target for drug discovery, but remains in the early experimental phase. In this study, we synthesized a set of six compounds based on a scaffold (alkyl-quinoxalin-2(1H)-one), new in the anti-QS of Gram-negative bacteria Aeromonas caviae Sch3. By quantifying biofilm formation, we were able to monitor the effect of these compounds from concentrations of 1 to 100 µM. Significant reduction in biofilm formation was achieved by 3-hexylylquinoxalin-2(1H)-one (11), 3-hexylylquinoxalin-2(1H)-one-6-carboxylic acid (12), and 3-heptylylquinoxalin-2(1H)-one-6-carboxylic acid (14), ranging from 11% to 59% inhibition of the biofilm. This pilot study contributes to the development of anti-QS compounds to overcome the clinical challenge of resistant bacteria strains.

scholarly journals Isolation and characterization of infectious Vibrio parahaemolyticus, the causative agent of AHPND, from the whiteleg shrimp (Litopenaeus vannamei)

2017 ◽  
Vol 44 (3) ◽  
pp. 470-479
Author(s):  
Patricia López-León ◽  
Antonio Luna-González ◽  
Ruth Escamilla-Montes ◽  
María del Carmen Flores-Miranda ◽  
Jesús A. Fierro-Coronado ◽  
...  
Keyword(s):  
Causative Agent ◽  
Biofilm Formation ◽  
Vibrio Parahaemolyticus ◽  
Bacterial Strains ◽  
Isolation And Characterization ◽  
Commercial Farms ◽  
Whiteleg Shrimp ◽  
Acute Hepatopancreatic Necrosis Disease ◽  
Selection Of

Vibrio parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (AHPND), was isolated from the hepatopancreas of moribund whiteleg shrimp of commercial farms from Guasave, Sinaloa, Mexico. The isolates were screened on thiosulfate citrate bile salt sucrose agar plates for the selection of green colonies and further characterized through PCR with AP3 primers, 89F/R primers, hemolysin genes, hemolytic and enzymatic activity, hydrophobicity, autoaggregation, and biofilm formation. Bioassays by immersion challenge were conducted to confirm the pathogenicity of selected bacterial strains. In addition, the LC50 was calculated for each isolate. All isolates (35) belonged to V. parahaemolyticus, but three isolates did not correspond to strains that cause AHPND since they were negative with 89F/R primers. All isolates were αhemolytic and showed biofilm formation (from moderate to strong). Isolates were hydrophobic or hydrophilic and showed high autoaggregation capacity. Eight strains did not kill shrimp and eleven were pathogenic, but differences in virulence were found among them perhaps due to α-hemolysis and differences in biofilm formation and hydrophobicity. Therefore, performed characterization may help to understand the pathogenicity of V. parahaemolyticus. Finally, results showed that smaller shrimp are less resistant to V. parahaemolyticus infection.

scholarly journals Sclerocarya birrea (A. Rich.) Hochst. and Sterculia setigera Del. extracts as a potential inhibitor of Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum CV026 virulence factors to combat bacterial pathogenicity

2021 ◽  
Vol 5 (1) ◽  
pp. 009-018
Author(s):  
Dramane Paré ◽  
Jotham Yhi-pênê N’do ◽  
Vincent Ouédraogo ◽  
Abdel Magid Arsène Ouoba ◽  
Adama Hilou
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ascorbic Acid ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Negative Control ◽  
Chromobacterium Violaceum ◽  
Bacterial Strains ◽  
Phytochemical Study ◽  
Pseudomonas Aeruginosa Pao1

The abuse of antibiotics has led to the widespread development of resistant bacterial strains, there is a need for the development of antimicrobial agents with new properties. Aim of this study was to determine the anti-quorum sensing potential (expression of virulence factor inhibition) of ethanolic extracts of S. birrea and S. setigera on Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1. The ability of the extracts to inhibit the production of violacein by C. violaceum and the biofilm formation of Pseudomonas aeruginosa was examined to determine anti-quorum sensing activity. The phytochemical screening and the determination of total polyphenols and total flavonoids were carried out. The antioxidant activity of the extracts was measured using anti-free radical DPPH model and the reducing of the ferric ion capacity. For the inhibition of the production of violacein, S. setigera presented the best result with an inhibition of 70.19% compared to the negative control which is 1% DMSO. This inhibition is greater than that of ascorbic acid used as a reference. This species was also the most active on biofilm formation with an inhibition of 72.24% compared to the negative control, it thus showed greater activity than that of ascorbic acid used as a positive reference. The phytochemical study revealed the presence of tannin, flavonoids, triterpenes, saponosides, coumarin in our two extracts. S. birrea gave the best total polyphenol content with 326.05 ± 117.90 mg EAG / g of extract and showed the best result on the DPPH radical with an inhibition of 73.33 ± 1.46% which is statistically equal to that of gallic acid used as a reference. These extracts showed good antibacterial activity by inhibiting the quorum sensing system. Thus, they could therefore be used for the manufacture of anti-quorum sensing phytomedicines without a bactericidal effect.

Extraction and characterization of sea anemones compound and its Anti bacterial and hemolytic studies

2020 ◽  
Vol 10 (4) ◽  
pp. 93-97
Author(s):  
Anil Kumar A ◽  
Raja Sheker K ◽  
Naveen B ◽  
Abhilash G ◽  
Akila CR
Keyword(s):  
Antibacterial Activity ◽  
Focal Point ◽  
Haemolytic Activity ◽  
Klebsiella Pneumonia ◽  
Bacterial Strains ◽  
Sea Anemones ◽  
Marine Plants ◽  
Heteractis Magnifica ◽  
Trididemnum Solidum

Seas assets that give us a variety of characteristic items to control bacterial, contagious and viral ailment and mostly utilized for malignancy chemotherapy practically from spineless creatures, for example, bryozoans, wipes, delicate corals, coelenterates, ocean fans, ocean bunnies, molluscs and echinoderms. In the previous 30 - 40 years, marine plants and creatures have been the focal point of overall endeavours to characterize the regular results of the marine condition. Numerous marine characteristic items have been effectively exceptional to the last phases of clinical preliminaries, including dolastatin-10, a group of peptides disengaged from Indian ocean rabbit, Dollabella auricularia. Ecteinascidin-743 from mangrove tunicate Ecteinascidia turbinata, Didemnins was isolated from Caribbean tunicate Trididemnum solidum and Conopeptides from cone snails (Conus sp.), and a developing number of up-and-comers have been chosen as promising leads for expanded pre-clinical appraisals. Sea anemones possess numerous tentacles containing stinging cells or cnidocytes. The stinging cells are equipped with small organelles known as nematocysts. The two species of sea anemones namely, Heteractis magnificaandStichodactyla haddoni, were collected from Mandapam coastal waters of Ramanathapuram district, Tamilnadu, India. The Nematocyst was collected and centrifuged, and the supernatant was lyophilized and stored for further analysis. The amount of protein from Heteractis Magnifica and Stichodactyla haddoni was estimated. The crude extract has shown haemolytic activity on chicken blood and goat blood. In the antibacterial activity of the sea anemone against six bacterial strains Staphylococcus aureus, Salmonella typhii, Salmonella paratyphii, Klebsiella pneumonia, Vibrio cholerae, Pseudomonas aeruginosa. Antibacterial activity of H. Magnifica and S.haddoni was measured as the radius of the zone of inhibition.

Whole-Genome Sequence Characterization of Primary Auxin-Responsive Aux/IAA Gene Family in Sorghum (Sorghum bicolor L.)

2010 ◽  
Vol 36 (4) ◽  
pp. 688-694
Author(s):  
Yi-Jun WANG ◽  
Yan-Ping LÜ ◽  
Qin XIE ◽  
De-Xiang DENG ◽  
Yun-Long BIAN
Keyword(s):  
Sorghum Bicolor ◽  
Gene Family ◽  
Genome Sequence ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Sequence Characterization ◽  
I Gene
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