This lead-resistant bacterial strain also demonstrated tolerance to high levels of cadmium and mercury along with multiple antibiotic resistance. Providencia alcalifaciens strain 2EA could be used for bioremediation of lead-contaminated

environmental sites, as it can efficiently precipitate lead as lead phosphate. Significance and Impact of the Study Providencia alcalifaciens strain 2EA resist lead nitrate up to 0.0014mol l-1 by precipitating soluble lead (Pb+2) as insoluble light brown solid. Scanning electron microscopy coupled with energy-dispersive X-ray spectrometric analysis (SEM-EDX) and X-ray diffraction spectroscopy (XRD) revealed extracellular light brown precipitate as lead orthophosphate mineral, Talazoparib that is, Pb9 (PO4)6 catalysed by phosphatase enzyme. Providencia alcalifaciens strain 2EA could be used for bioremediation of lead-contaminated environmental sites, as it can efficiently precipitate lead as insoluble lead phosphate.”
“In Pseudomonas aeruginosa, the chromosomally ZIETDFMK encoded class C cephalosporinase (AmpC beta-lactamase) is often responsible for high-level resistance to beta-lactam

antibiotics. Despite years of study of these important beta-lactamases, knowledge regarding how amino acid sequence dictates function of the AmpC Pseudomonas-derived cephalosporinase (PDC) remains scarce. Insights into structure-function relationships are crucial to the design of both beta-lactams and high-affinity inhibitors. In order to understand how PDC recognizes the C-3/C-4 carboxylate of beta-lactams, we first examined a molecular model of a P. aeruginosa AmpC beta-lactamase, PDC-3, in complex with a boronate inhibitor that possesses a side chain that mimics the thiazolidine/dihydrothiazine ring and the C-3/C-4 carboxylate characteristic of beta-lactam substrates. We next tested the hypothesis generated by our model, i.e. that more than one amino acid residue is involved in recognition

of the C-3/C-4 beta-lactam carboxylate, and engineered alanine variants at three putative carboxylate binding amino acids. Antimicrobial susceptibility testing showed that the PDC-3 beta-lactamase maintains a high level of PRN1371 cost activity despite the substitution of C-3/C-4 beta-lactam carboxylate recognition residues. Enzyme kinetics were determined for a panel of nine penicillin and cephalosporin analog boronates synthesized as active site probes of the PDC-3 enzyme and the Arg349Ala variant. Our examination of the PDC-3 active site revealed that more than one residue could serve to interact with the C-3/C-4 carboxylate of the beta-lactam. This functional versatility has implications for novel drug design, protein evolution, and resistance profile of this enzyme.