02032nas a2200253   4500008004100000022001400041245014000055210006900195260005700264300001400321490000700335520111700342653001301459653002001472653001401492653001801506653001701524653002301541100002901564700001601593700001501609700002401624856013001648       2012                        eng d  a1590-426100aCharacterization of a new bacillus cereus ATUAVP1846 strain producing penicillin V acylase, and optimization of fermentation parameters0 aCharacterization of a new bacillus cereus ATUAVP1846 strain prod  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcSEP  a1287-12930 v623 a<p>Penicillin acylases are involved chiefly in the industrial production of semisynthetic penicillins, which remain the most widely used group of antibiotics. We have isolated a new bacterial strain ATUAVP1846 that produces penicillin V acylase (PVA). Phylogenetic analysis using 16S rRNA sequencing showed 99.37% homology with Bacillus cereus. Maximum PVA production was observed with B. cereus ATUAVP1846 at 30A degrees C, pH 7 after 24 h fermentation time under submerged conditions. Highest enzyme productivity was achieved using sucrose as carbon source, and tryptone and ammonium hydrogen phosphate as nitrogen sources. Minimal medium containing 0.4% glucose and 0.3% ammonium hydrogen phosphate was found to be optimal for maximum PVA production from B. cereus ATUAVP1846. The crude enzyme from B. cereus ATUAVP1846 was partially purified using ammonium sulfate fractionation and showed highest enzymatic activity in the hydrolysis of penicillin V at 40A degrees C and pH 6. The crude enzyme preparation also showed unique substrate specificity, preferring ampicillin and cephalexin over penicillin V.</p>10a16S rRNA10aBacillus cereus10aisolation10aNtn hydrolase10aOptimization10aPenicillin acylase1 aSunder, Avinash, Vellore1 aKumar, Atul1 aNaik, Neha1 aPundle, Archana, V.  uhttp://library.ncl.res.in/content/characterization-new-bacillus-cereus-atuavp1846-strain-producing-penicillin-v-acylase-and-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<p>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.</p>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-attenuate