<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Fang, Bing</style></author><author><style face="normal" font="default" size="100%">Jiang, Ying</style></author><author><style face="normal" font="default" size="100%">Rotello, Vincent M</style></author><author><style face="normal" font="default" size="100%">Nüsslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Santore, Maria M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Easy come easy go: surfaces containing immobilized nanoparticles or isolated polycation chains facilitate removal of captured Staphylococcus aureus by retarding bacterial bond maturation.</style></title><secondary-title><style face="normal" font="default" size="100%">ACS Nano</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ACS Nano</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Nanoparticles</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyamines</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword><keyword><style  face="normal" font="default" size="100%">Surface Properties</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014 Feb 25</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">8</style></volume><pages><style face="normal" font="default" size="100%">1180-90</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Adhesion of bacteria is a key step in the functioning of antimicrobial surfaces or certain types of on-line sensors. The subsequent removal of these bacteria, within a &amp;sim; 10-30 min time frame, is equally important but complicated by the tendency of bacterial adhesion to strengthen within minutes of initial capture. This study uses Staphylococcus aureus as a model bacterium to demonstrate the general strategy of clustering adhesive surface functionality (at length scales smaller than the bacteria themselves) on otherwise nonadhesive surfaces to capture and retain bacteria (easy come) while limiting the progressive strengthening of adhesion. The loose attachment facilitates bacteria removal by moderate shearing flow (easy go). This strategy is demonstrated using surfaces containing sparsely and randomly arranged immobilized amine-functionalized nanoparticles or poly-l-lysine chains, about 10 nm in size. The rest of the surface is backfilled with a nonadhesive polyethylene glycol (PEG) brush that, by itself, repels S. aureus. The nanoparticles or polymer chains cluster cationic functionality, providing small regions that attract negatively charged S. aureus cells. Compared with surfaces of nearly uniform cationic character where S. aureus adhesion quickly becomes strong (on a time scale less than 5 min), placement of cationic charge in small clusters retards or prevents processes that increase bacteria adhesion on a time scale of &amp;sim; 30 min, providing &amp;quot;easy go&amp;quot; surfaces.&lt;/p&gt;
</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Fang, Bing</style></author><author><style face="normal" font="default" size="100%">Gon, Saugata</style></author><author><style face="normal" font="default" size="100%">Park, Myoung</style></author><author><style face="normal" font="default" size="100%">Kumar, Kushi-Nidhi</style></author><author><style face="normal" font="default" size="100%">Rotello, Vincent M</style></author><author><style face="normal" font="default" size="100%">Nusslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Santore, Maria M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Bacterial adhesion on hybrid cationic nanoparticle-polymer brush surfaces: ionic strength tunes capture from monovalent to multivalent binding.</style></title><secondary-title><style face="normal" font="default" size="100%">Colloids Surf B Biointerfaces</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Colloids Surf B Biointerfaces</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Adhesion</style></keyword><keyword><style  face="normal" font="default" size="100%">Cations</style></keyword><keyword><style  face="normal" font="default" size="100%">Nanoparticles</style></keyword><keyword><style  face="normal" font="default" size="100%">Osmolar Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Polyethylene Glycols</style></keyword><keyword><style  face="normal" font="default" size="100%">Polylysine</style></keyword><keyword><style  face="normal" font="default" size="100%">Silicon Dioxide</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword><keyword><style  face="normal" font="default" size="100%">Static Electricity</style></keyword><keyword><style  face="normal" font="default" size="100%">Surface Properties</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011 Oct 1</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">87</style></volume><pages><style face="normal" font="default" size="100%">109-15</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">This paper describes the creation of hybrid surfaces containing cationic nanoparticles and biocompatible PEG (polyethylene glycol) brushes that manipulate bacterial adhesion for potential diagnostic and implant applications. Here, ∼10 nm cationically functionalized gold nanoparticles are immobilized randomly on negative silica surfaces at tightly controlled surface loadings, and the remaining areas are functionalized with a hydrated PEG brush, using a graft copolymer of poly-l-lysine and PEG (PLL-PEG), containing 2000 molecular weight PEG chains and roughly 30% functionalization of the PLL. The cationic nanoparticles attract the negative surfaces of suspended Staphylococcus aureus bacteria while the PEG brush exerts a steric repulsion. With the nanoparticle and PEG brush heights on the same lengthscale, variations in ionic strength are demonstrated to profoundly influence the capture of S. aureus on these surfaces. For bacteria captured from gentle flow, a crossover from multivalent to univalent binding is demonstrated as the Debye length is increased from 1 to 4 nm. In the univalent regime, 1 um diameter spherical bacteria are captured and held by single nanoparticles. In the multivalent regime, there is an adhesion threshold in the surface density of nanoparticles needed for bacterial capture. The paper also documents an interesting effect concerning the relaxations in the PLL-PEG brush itself. For brushy surfaces containing no nanoparticles, bacterial adhesion persists on newly formed brushes, but is nearly eliminated after these brushes relax, at constant mass in buffer for 12h. Thus brushy relaxations increase biocompatibility.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/21640564?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Kalasin, Surachate</style></author><author><style face="normal" font="default" size="100%">Dabkowski, Jeffrey</style></author><author><style face="normal" font="default" size="100%">Nüsslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Santore, Maria M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The role of nano-scale heterogeneous electrostatic interactions in initial bacterial adhesion from flow: a case study with Staphylococcus aureus.</style></title><secondary-title><style face="normal" font="default" size="100%">Colloids Surf B Biointerfaces</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Colloids Surf B Biointerfaces</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Adsorption</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Adhesion</style></keyword><keyword><style  face="normal" font="default" size="100%">Methacrylates</style></keyword><keyword><style  face="normal" font="default" size="100%">Nylons</style></keyword><keyword><style  face="normal" font="default" size="100%">Particle Size</style></keyword><keyword><style  face="normal" font="default" size="100%">Serum Albumin, Bovine</style></keyword><keyword><style  face="normal" font="default" size="100%">Silicon Dioxide</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword><keyword><style  face="normal" font="default" size="100%">Static Electricity</style></keyword><keyword><style  face="normal" font="default" size="100%">Surface Properties</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010 Apr 1</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">76</style></volume><pages><style face="normal" font="default" size="100%">489-95</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">This study investigated the initial adhesion of Staphylococcus aureus from flowing buffer onto modified albumin films with the objective of probing the influence of electrostatic heterogeneity on bacterial adhesion. Electrostatic heterogeneity, on the lengthscale of 10-100 nm, was incorporated into the protein film through the irreversible random deposition of small amounts of polycation coils to produce isolated positive &quot;patches&quot; on the otherwise negative albumin surface before exposure to bacteria, which also possess a net negative surface charge. The system was benchmarked against an appropriate analog using 1 microm silica spheres and the same cationic patches on a silica substrate. Bacterial adhesion from flow was measured with the surface oriented vertically to eliminate gravitational forces between the bacteria and collector. In both systems, a threshold in the surface density of polycation patches needed for bacterial (or silica particle) capture indicated multivalent binding: multiple polycation patches were needed to adhere the bacteria (particles). The shifting of the threshold to greater patch concentrations at lower ionic strengths confirmed that the electrostatic interaction area (zone of influence) was a key factor in modulating the interactions. The role of the contact area in this manner is important because it enables a quantitative explanation of counterintuitive bacterial adhesion onto net negative surfaces. The study further revealed a hydrodynamic crossover from a regime where flow aids bacterial adhesion to one where flow impedes adhesion. An explanation is put forth in terms of the relative hydrodynamic and surface forces.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/20074917?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lienkamp, Karen</style></author><author><style face="normal" font="default" size="100%">Kumar, Kushi-Nidhi</style></author><author><style face="normal" font="default" size="100%">Som, Abhigyan</style></author><author><style face="normal" font="default" size="100%">Nüsslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Tew, Gregory N</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">&quot;Doubly selective&quot; antimicrobial polymers: how do they differentiate between bacteria?</style></title><secondary-title><style face="normal" font="default" size="100%">Chemistry</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Chemistry</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anti-Infective Agents</style></keyword><keyword><style  face="normal" font="default" size="100%">Biomimetic Materials</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Microbial Sensitivity Tests</style></keyword><keyword><style  face="normal" font="default" size="100%">Peptidoglycan</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymers</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009 Nov 2</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">11710-4</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We have investigated how doubly selective synthetic mimics of antimicrobial peptides (SMAMPs), which can differentiate not only between bacteria and mammalian cells, but also between Gram-negative and Gram-positive bacteria, make the latter distinction. By dye-leakage experiments on model vesicles and complementary experiments on bacteria, we were able to relate the Gram selectivity to structural differences of these bacteria types. We showed that the double membrane of E. coli rather than the difference in lipid composition between E. coli and S. aureus was responsible for Gram selectivity. The molecular-weight-dependent antimicrobial activity of the SMAMPs was shown to be a sieving effect: while the 3000 g mol(-1) SMAMP was able to penetrate the peptidoglycan layer of the Gram-positive S. aureus bacteria, the 50000 g mol(-1) SMAMP got stuck and consequently did not have antimicrobial activity.</style></abstract><issue><style face="normal" font="default" size="100%">43</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/19790208?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Madkour, Ahmad E</style></author><author><style face="normal" font="default" size="100%">Dabkowski, Jeffery M</style></author><author><style face="normal" font="default" size="100%">Nusslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Tew, Gregory N</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Fast disinfecting antimicrobial surfaces.</style></title><secondary-title><style face="normal" font="default" size="100%">Langmuir</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Langmuir</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anti-Bacterial Agents</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Glass</style></keyword><keyword><style  face="normal" font="default" size="100%">Microbial Sensitivity Tests</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Structure</style></keyword><keyword><style  face="normal" font="default" size="100%">Particle Size</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymethacrylic Acids</style></keyword><keyword><style  face="normal" font="default" size="100%">Silicon</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword><keyword><style  face="normal" font="default" size="100%">Surface Properties</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009 Jan 20</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">1060-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the &quot;grafting from&quot; technique. Surface-initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/19177651?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lienkamp, Karen</style></author><author><style face="normal" font="default" size="100%">Madkour, Ahmad E</style></author><author><style face="normal" font="default" size="100%">Musante, Ashlan</style></author><author><style face="normal" font="default" size="100%">Nelson, Christopher F</style></author><author><style face="normal" font="default" size="100%">Nüsslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Tew, Gregory N</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Antimicrobial polymers prepared by ROMP with unprecedented selectivity: a molecular construction kit approach.</style></title><secondary-title><style face="normal" font="default" size="100%">J Am Chem Soc</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Am. Chem. Soc.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anti-Infective Agents</style></keyword><keyword><style  face="normal" font="default" size="100%">Antimicrobial Cationic Peptides</style></keyword><keyword><style  face="normal" font="default" size="100%">Biomimetic Materials</style></keyword><keyword><style  face="normal" font="default" size="100%">Erythrocytes</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Hemolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrophobic and Hydrophilic Interactions</style></keyword><keyword><style  face="normal" font="default" size="100%">Microbial Sensitivity Tests</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">Norbornanes</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymers</style></keyword><keyword><style  face="normal" font="default" size="100%">Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008 Jul 30</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">130</style></volume><pages><style face="normal" font="default" size="100%">9836-43</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Synthetic Mimics of Antimicrobial Peptides (SMAMPs) imitate natural host-defense peptides, a vital component of the body's immune system. This work presents a molecular construction kit that allows the easy and versatile synthesis of a broad variety of facially amphiphilic oxanorbornene-derived monomers. Their ring-opening metathesis polymerization (ROMP) and deprotection provide several series of SMAMPs. Using amphiphilicity, monomer feed ratio, and molecular weight as parameters, polymers with 533 times higher selectivitiy (selecitviy = hemolytic concentration/minimum inhibitory concentration) for bacteria over mammalian cells were discovered. Some of these polymers were 50 times more selective for Gram-positive over Gram-negative bacteria while other polymers surprisingly showed the opposite preference. This kind of &quot;double selectivity&quot; (bacteria over mammalian and one bacterial type over another) is unprecedented in other polymer systems and is attributed to the monomer's facial amphiphilicity.</style></abstract><issue><style face="normal" font="default" size="100%">30</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/18593128?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Al-Badri, Zoha M</style></author><author><style face="normal" font="default" size="100%">Som, Abhigyan</style></author><author><style face="normal" font="default" size="100%">Lyon, Sarah</style></author><author><style face="normal" font="default" size="100%">Nelson, Christopher F</style></author><author><style face="normal" font="default" size="100%">Nüsslein, Klaus</style></author><author><style face="normal" font="default" size="100%">Tew, Gregory N</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Investigating the effect of increasing charge density on the hemolytic activity of synthetic antimicrobial polymers.</style></title><secondary-title><style face="normal" font="default" size="100%">Biomacromolecules</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biomacromolecules</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amines</style></keyword><keyword><style  face="normal" font="default" size="100%">Anti-Infective Agents</style></keyword><keyword><style  face="normal" font="default" size="100%">Antimicrobial Cationic Peptides</style></keyword><keyword><style  face="normal" font="default" size="100%">Chemistry, Pharmaceutical</style></keyword><keyword><style  face="normal" font="default" size="100%">Drug Design</style></keyword><keyword><style  face="normal" font="default" size="100%">Erythrocytes</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Hemolysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Lipids</style></keyword><keyword><style  face="normal" font="default" size="100%">Magnetic Resonance Spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Chemical</style></keyword><keyword><style  face="normal" font="default" size="100%">Peptides</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymers</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008 Oct</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">9</style></volume><pages><style face="normal" font="default" size="100%">2805-10</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The current study is aimed at investigating the effect of fine-tuning the cationic character of synthetic mimics of antimicrobial peptides (SMAMPs) on the hemolytic and antibacterial activities. A series of novel norbornene monomers that carry one, two, or three Boc-protected amine functionalities was prepared. Ring-opening metathesis polymerization (ROMP) of the monomers, followed by deprotection of the amine groups resulted in cationic antimicrobial polynorbornenes that carry one, two, and three charges per monomer repeat unit. Increasing the number of amine groups on the most hydrophobic polymer reduced its hemolytic activity significantly. To understand the membrane activity of these polymers, we conducted dye leakage experiments on lipid vesicles that mimic bacteria and red blood cell membranes, and these results showed a strong correlation with the hemolysis data.</style></abstract><issue><style face="normal" font="default" size="100%">10</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/18816096?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gov, Yael</style></author><author><style face="normal" font="default" size="100%">Borovok, Ilya</style></author><author><style face="normal" font="default" size="100%">Korem, Moshe</style></author><author><style face="normal" font="default" size="100%">Singh, Vineet K</style></author><author><style face="normal" font="default" size="100%">Jayaswal, Radheshyam K</style></author><author><style face="normal" font="default" size="100%">Wilkinson, Brian J</style></author><author><style face="normal" font="default" size="100%">Rich, Stephen M</style></author><author><style face="normal" font="default" size="100%">Balaban, Naomi</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Quorum sensing in Staphylococci is regulated via phosphorylation of three conserved histidine residues.</style></title><secondary-title><style face="normal" font="default" size="100%">J Biol Chem</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Biol. Chem.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Blotting, Northern</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Communication</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrophoresis, Polyacrylamide Gel</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Histidine</style></keyword><keyword><style  face="normal" font="default" size="100%">Mice</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutagenesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutagenesis, Site-Directed</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenotype</style></keyword><keyword><style  face="normal" font="default" size="100%">Phosphorylation</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">Plasmids</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Structure, Tertiary</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Antisense</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Homology, Amino Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Signal Transduction</style></keyword><keyword><style  face="normal" font="default" size="100%">Staphylococcus aureus</style></keyword><keyword><style  face="normal" font="default" size="100%">Time Factors</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004 Apr 9</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">279</style></volume><pages><style face="normal" font="default" size="100%">14665-72</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Staphylococcus aureus cause infections by producing toxins, a process regulated by cell-cell communication (quorum sensing) through the histidine-phosphorylation of the target of RNAIII-activating protein (TRAP). We show here that TRAP is highly conserved in staphylococci and contains three completely conserved histidine residues (His-66, His-79, His-154) that are phosphorylated and essential for its activity. This was tested by constructing a TRAP(-) strain with each of the conserved histidine residues changed to alanine by site-directed mutagenesis. All mutants were tested for pathogenesis in vitro (expression of RNAIII and hemolytic activity) and in vivo (murine cellulitis model). Results show that RNAIII is not expressed in the TRAP(-) strain, that it is non hemolytic, and that it does not cause disease in vivo. These pathogenic phenotypes could be rescued in the strain containing the recovered traP, confirming the importance of TRAP in S. aureus pathogenesis. The phosphorylation of TRAP mutated in any of the conserved histidine residues was significantly reduced, and mutants defective in any one of these residues were non-pathogenic in vitro or in vivo, whereas those mutated in a non-conserved histidine residue (His-124) were as pathogenic as the wild type. These results confirm the importance of the three conserved histidine residues in TRAP activity. The phosphorylation pattern, structure, and gene organization of TRAP deviates from signaling molecules known to date, suggesting that TRAP belongs to a novel class of signal transducers.</style></abstract><issue><style face="normal" font="default" size="100%">15</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/14726534?dopt=Abstract</style></custom1></record></records></xml>