II. Broad host range, high copy number, RSF1010-derived vectors, and a host-vector system for gene cloning in Pseudomonas . Gene 1981, 16:237–247.PubMedCrossRef 59. Pratt LA, Kolter R: Genetic analysis of Escherichia coli biofilm formation: roles of flagella, motility, chemotaxis and type I pili. Mol Microbiol 1998, buy Paclitaxel 30:285–293.PubMedCrossRef Authors’ contributions VdL planned and coordinated the research project. VdL, EMG and BC conceived and designed the experiments. EMG performed the pBAM1 characterization

while BC constructed and implemented the pBAM1-GFP plasmid. MAR streamlined the design of the different modules of the pBAM1 plasmid. All authors have read and approved the manuscript.”
“Background Transition metals play an essential

role in all organisms as they are used as structural or catalytic cofactor in a very large number of proteins [1]. Among these elements, zinc is PLX4032 in vivo the one which is found in the largest number of enzymes with known three-dimensional structure [2] and recent bioinformatics investigations have established that zinc-binding proteins constitute about 5% of bacterial proteomes [3]. Despite its abundant employment in proteins, the intracellular concentration of zinc must be accurately controlled to prevent its potential toxicity. To this aim bacteria have developed effective systems to regulate the balance between uptake and export of zinc and maintain an optimal intracellular level of this metal [4–6]. In Escherichia coli K12, for example, zinc efflux is achieved through the two transporters ZitB, a member of the cation diffusion facilitator family [7], and ZntA, a P-type ATPase [8]. ZntA synthesis is regulated by ZntR [9], a zinc-responsive Mer-like transcriptional regulator that activates znt A transcription by binding to zinc, thus favoring the efflux from the cell of the metal in excess. Zinc uptake is ensured by a few transporters characterized by different affinity for the metal. Under conditions of moderate zinc availability, metal uptake is carried

out by the low affinity permease Rutecarpine ZupT, a member of the ZIP family of transporters [10]. In contrast, when bacteria grow in environments characterized by very low zinc availability, zinc import is ensured by the high affinity zinc transporter ZnuABC [4, 11], whose synthesis is tightly controlled by the binding of this metal to the promoter of zur gene [12]. Studies carried out in different bacterial species have established that ZnuABC is strictly required to promote an efficient microbial growth in media deficient in zinc and to ensure bacterial virulence, indicating that zinc availability in the infected host is very limited and that several bacteria strictly rely on this specific transporter to compete with their host for zinc binding [13–20]. It has been recently shown that in some bacterial species the fine-tuning of zinc uptake involves another protein, ZinT (formerly known as YodA), which was initially identified in E.