02273nas a2200241 4500008004100000022001400041245014400055210006900199260007900268300000800347490000700355520135400362653002901716653001001745653001001755653002101765100002201786700002901808700002601837700001901863700002101882856012801903 2014 eng d a0141-022900aNew role for penicillin acylases: degradation of acyl homoserine lactone quorum sensing signals by Kluyvera citrophila penicillin G acylase0 aNew role for penicillin acylases degradation of acyl homoserine  a360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USAbELSEVIER SCIENCE INCcMAR a1-70 v563 a

Use of penicillin acylases for the production of semi-synthetic penicillins is well-known. Escherichia coli penicillin G acylase (EcPGA) has been extensively used for this purpose; however, Kluyvera citrophila penicillin G acylase (KcPGA) is assumed to be a better substitute, owing to its increased resilience to extreme pH conditions and ease of immobilization. In the present article we report a new dimension for the amidase activity of KcPGA by demonstrating its ability to cleave bacterial quorum sensing signal molecules, acyl homoserine lactones (AHL) with acyl chain length of 6-8 with or without oxo-substitution at third carbon position. Initial evidence of AHL degrading capability of KcPGA was obtained using CV026 based bioassay method. Kinetic studies performed at pH 8.0 and 50 degrees C revealed 3-oxo-C6 HSL to be the best substrate for the enzyme with V-max and K-m values of 21.37+0.85 mM/h/mg of protein and 0.1+0.01 mM, respectively. C6 HSL was found to be the second best substrate with V-max. and K-m value of 10.06+0.27 mM/h/mg of protein and 0.28+0.02 mM, respectively. Molecular modeling and docking studies performed on the active site of the enzyme support these findings by showing the fitting of AHLs perfectly within the hydrophobic pocket of the enzyme active site. (c) 2013 Elsevier Inc. All rights reserved.

10aAcyl homoserine lactones10aCV02610aKcPGA10aQuorum quenching1 aMukherji, Ruchira1 aVarshney, Nishant, Kumar1 aPanigrahi, Priyabrata1 aSuresh, C., G.1 aPrabhune, Asmita uhttp://library.ncl.res.in/content/new-role-penicillin-acylases-degradation-acyl-homoserine-lactone-quorum-sensing-signals-001908nas a2200217 4500008004100000022001400041245016500055210006900220260007900289300001200368490000800380520103200388653001601420653002401436653001001460653002101470653003101491100002201522700002101544856012501565 2015 eng d a0273-228900aPossible correlation between bile salt hydrolysis and ahl deamidation: staphylococcus epidermidis RM1, a potent quorum quencher and bile salt hydrolase producer0 aPossible correlation between bile salt hydrolysis and ahl deamid a999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USAbHUMANA PRESS INCcMAY a140-1500 v1763 a

The aim of the present work was to isolate a bile salt hydrolase (BSH) producer from fermented soy curd and explore the ability of the BSH produced to cleave bacterial quorum sensing signals. Bacterial isolates with possible ability to deconjugate bile salts were enriched and isolated on De Man, Rogosa and Sharpe (MRS) medium containing 0.2 % bile salts. BSH-producing positive isolate with orange-pink-pigmented colonies was isolated and was identified as a strain of Staphylococcus epidermidis using biochemical and phylogenetic tools. S. epidermidis RM1 was shown to possess both potent BSH and N-acyl homoserine lactone (AHL) cleavage activity. Genetic basis of this dual-enzyme activity was explored by means of specific primers designed using S. epidermidis ATCC 12228 genome as template. It was observed that a single enzyme was not responsible for both the activity. Two different genetic elements corresponding to each of the enzymatic activity were successfully amplified from the genomic DNA of the isolate.

10aAHL acylase10aBile salt hydrolase10aCV02610aQuorum quenching10aStaphylococcus epidermidis1 aMukherji, Ruchira1 aPrabhune, Asmita uhttp://library.ncl.res.in/content/possible-correlation-between-bile-salt-hydrolysis-and-ahl-deamidation-staphylococcus-002534nas a2200265 4500008004100000022001400041245013800055210006900193260000800262300001400270490000800284520159300292653003701885653001801922653001701940653002401957653002101981100002902002700002202031700002602053700002402079700001402103700002002117856013102137 2017 eng d a0175-759800aPenicillin V acylases from gram-negative bacteria degrade N-acylhomoserine lactones and attenuate virulence in Pseudomonas aeruginosa0 aPenicillin V acylases from gramnegative bacteria degrade Nacylho cMAR a2383-23950 v1013 a

Virulence pathways in gram-negative pathogenic bacteria are regulated by quorum sensing mechanisms, through the production and sensing of N-acylhomoserine lactone (AHL) signal molecules. Enzymatic degradation of AHLs leading to attenuation of virulence (quorum quenching) could pave the way for the development of new antibacterials. Penicillin V acylases (PVAs) belong to the Ntn hydrolase superfamily, together with AHL acylases. PVAs are exploited widely in the pharmaceutical industry, but their role in the natural physiology of their native microbes is not clearly understood. This report details the characterization of AHL degradation activity by homotetrameric PVAs from two gram-negative plant pathogenic bacteria, Pectobacterium atrosepticum (PaPVA) and Agrobacterium tumefaciens (AtPVA). Both the PVAs exhibited substrate specificity for degrading long-chain AHLs. Exogenous addition of these enzymes into Pseudomonas aeruginosa greatly diminished the production of elastase and pyocyanin and biofilm formation and increased the survival rate in an insect model of acute infection. Subtle structural differences in the PVA active site that regulate specificity for acyl chain length have been characterized, which could reflect the evolution of AHL-degrading acylases in relation to the environment of the bacteria that produce them and also provide strategies for enzyme engineering. The potential for using these enzymes as therapeutic agents in clinical applications and a few ideas about their possible significance in microbial physiology have also been discussed.

10aN-acylhomoserine lactone acylase10aNtn hydrolase10apathogenesis10aPenicillin Vacylase10aQuorum quenching1 aSunder, Avinash, Vellore1 aUtari, Putri, Dwi1 aRamasamy, Sureshkumar1 avan Merkerk, Ronald1 aQuax, Wim1 aPundle, Archana uhttp://library.ncl.res.in/content/penicillin-v-acylases-gram-negative-bacteria-degrade-n-acylhomoserine-lactones-and-attenuate01597nas a2200205 4500008004100000022001400041245011200055210006900167260000800236300001100244490000600255520088300261653001301144653001801157653002101175653001701196100002201213700002501235856013101260 2018 eng d a2054-570300aPhotophysical studies on curcumin-sophorolipid nanostructures: applications in quorum quenching and imaging0 aPhotophysical studies on curcuminsophorolipid nanostructures app cFEB a1708650 v53 a

Sophorolipid biosurfactants are biodegradable, less toxic and FDA approved. The purified acidic form of sophorolipid is stimuli-responsive with self-assembling properties and used for solubilizing hydrophobic drugs. This study encapsulated curcumin (CU) with acidic sophorolipid (ASL) micelles and analysed using photophysical studies like UV-visible spectroscopy, photoluminescence (PL) spectroscopy and timecorrelated single photon counting (TCSPC). TEM images have revealed ellipsoid micelles of approximately 100nm size and were confirmed by dynamic light scattering. The bacterial fluorescence uptake studies showed the uptake of formed CUASL nanostructures into both Gram-positive and Gram-negative bacteria. They also showed quorum quenching activity against Pseudomonas aeruginosa. The results have demonstrated this system has potential theranostic applications.

10acurcumin10aphotophysical10aQuorum quenching10aSophorolipid1 aVasudevan, Sahana1 aPrabhune, Asmita, A. uhttp://library.ncl.res.in/content/photophysical-studies-curcumin-sophorolipid-nanostructures-applications-quorum-quenching-and