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Epigallocatechin-Gallate Enhances the Activity of Tetracycline in Staphylococci by Inhibiting Its Efflux from Bacterial Cells. Andrea Sudano Roccaro, 2004.Epigallocatechin-gallate (EGCg), the major catechin present in green tea extracts, has been shown to have several antibacterial activities, limiting bacterial growth and invasion and acting in synergy with ß-lactam antibiotics . In this article, we report that EGCg at doses half and below its calculated MIC of 100 µg/ml, is able to reverse tetracycline resistance in staphylococcal isolates expressing the specific efflux pump Tet(K) and appears to improve the MICs of tetracycline for susceptible staphylococcal isolates as well . The visible effect of EGCg is an increased accumulation of tetracycline inside bacterial cells . This effect is likely due to the inhibition of pump activity, and it is evident not only for Tet(K) pumps but also for efflux pumps of a different class [Tet(B)] . In summary, our data indicate that the observed dramatic enhancement by EGCg of tetracycline activity for resistant staphylococcal isolates is caused by impairment of tetracycline efflux pump activity and increased intracellular retention of the drug, suggesting a possible use of EGCg as an adjuvant in antibacterial therapy . Interactions between Integrase and Excisionase in the Phage Lambda Excisive Nucleoprotein Complex. Eun Hee Cho, 2002.Bacteriophage lambda site-specific recombination comprises two overall reactions, integration into and excision from the host chromosome . Lambda integrase (Int) carries out both reactions . During excision, excisionase (Xis) helps Int to bind DNA and introduces a bend in the DNA that facilitates formation of the proper excisive nucleoprotein complex . The carboxyl-terminal  -helix of Xis is thought to interact with Int through direct protein-protein interactions . In this study, we used gel mobility shift assays to show that the amino-terminal domain of Int maintained cooperative interactions with Xis . This finding indicates that the amino-terminal arm-type DNA binding domain of Int interacts with Xis .
Autotransporters as Scaffolds for Novel Bacterial Adhesins: Surface Properties of Escherichia coli Cells Displaying Jun/Fos Dimerization Domains. Esteban Veiga, 2003.Hybrid proteins containing the ß-autotransporter domain of the immunoglobulin A (IgA) protease of Neisseria gonorrhoea (IgAß) and the partner leucine zippers of the eukaryotic transcriptional factors Fos and Jun were expressed in Escherichia coli. Such fusion proteins targeted the leucine zipper modules to the cell surface . Cells displaying the Junß sequence flocculated shortly after induction of the hybrid protein . E . coli cells expressing separately Fosß and Junß chimeras formed stable bacterial consortia . These associations were physically held by tight intercell ties caused by the protein-protein interactions of matching dimerization domains . The role of autotransporters in the emergence of new adhesins is discussed .
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