@article{AwanSchiebelBoehmetal.2019, author = {Awan, Asad Bashir and Schiebel, Juliane and Boehm, Alexander and Nitschke, Joerg and Sarwar, Yasra and Schierack, Peter and Ali, Aamir}, title = {Association of biofilm formation and cytotoxic potential with multidrug resistance in clinical isolates of pseudomonas aeruginosa}, series = {EXCLI Journal}, volume = {18}, journal = {EXCLI Journal}, publisher = {Leibniz Research Centre for Working Environment and Human Factors}, address = {Dortmund}, issn = {1611-2156}, doi = {10.17179/excli2018-1948}, pages = {79 -- 90}, year = {2019}, abstract = {Multidrug resistant (MDR) Pseudomonas aeruginosa having strong biofilm potential and virulence factors are a serious threat for hospitalized patients having compromised immunity In this study, 34 P. aeruginosa isolates of human origin (17 MDR and 17 non-MDR clinical isolates) were checked for biofilm formation potential in enriched and minimal media. The biofilms were detected using crystal violet method and a modified software package of the automated VideoScan screening method. Cytotoxic potential of the isolates was also investigated on HepG2, LoVo and T24 cell lines using automated VideoScan technology. Pulse field gel electrophoresis revealed 10 PFGE types in MDR and 8 in non-MDR isolates. Although all isolates showed biofilm formation potential, strong biofilm formation was found more in enriched media than in minimal media. Eight MDR isolates showed strong biofilm potential in both enriched and minimal media by both detection methods. Strong direct correlation between crystal violet and VideoScan methods was observed in identifying strong biofilm forming isolates. High cytotoxic effect was observed by 4 isolates in all cell lines used while 6 other isolates showed high cytotoxic effect on T24 cell line only. Strong association of multidrug resistance was found with biofilm formation as strong biofilms were observed significantly higher in MDR isolates (p-value < 0.05) than non-MDR isolates. No significant association of cytotoxic potential with multidrug resistance or biofilm formation was found (p-value > 0.05). The MDR isolates showing significant cytotoxic effects and strong biofilm formation impose a serious threat for hospitalized patients with weak immune system.}, language = {en} } @article{SchmidtRoedigerGruneretal.2016, author = {Schmidt, Carsten and Roediger, Stefan and Gruner, Melanie and Moncsek, Anja and Stohwasser, Ralf and Hanack, Katja and Schierack, Peter and Schroeder, Christian}, title = {Multiplex localization of sequential peptide epitopes by use of a planar microbead chip}, series = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, volume = {908}, journal = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0003-2670}, doi = {10.1016/j.aca.2015.12.030}, pages = {150 -- 160}, year = {2016}, abstract = {Epitope mapping is crucial for the characterization of protein-specific antibodies. Commonly, small overlapping peptides are chemically synthesized and immobilized to determine the specific peptide sequence. In this study, we report the use of a fast and inexpensive planar microbead chip for epitope mapping. We developed a generic strategy for expressing recombinant peptide libraries instead of using expensive synthetic peptide libraries. A biotin moiety was introduced in vivo at a defined peptide position using biotin ligase. Peptides in crude Escherichia coli lysate were coupled onto streptavidin-coated microbeads by incubation, thereby avoiding tedious purification procedures. For read-out we used a multiplex planar microbead chip with size- and fluorescence-encoded microbead populations. For epitope mapping, up to 18 populations of peptide-loaded microbeads (at least 20 microbeads per peptide) displaying the primary sequence of a protein were analyzed simultaneously. If an epitope was recognized by an antibody, a secondary fluorescence-labeled antibody generated a signal that was quantified, and the mean value of all microbeads in the population was calculated. We mapped the epitopes for rabbit anti-PA28 gamma (proteasome activator 28 gamma) polyclonal serum, for a murine monoclonal antibody against PA28 gamma, and for a murine monoclonal antibody against the hamster polyoma virus major capsid protein VP1 as models. In each case, the identification of one distinct peptide sequence out of up to 18 sequences was possible. Using this approach, an epitope can be mapped multiparametrically within three weeks. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} }