Structure and metal-binding properties of PA4063, a novel player in periplasmic zinc trafficking by Pseudomonas aeruginosa

The capability to obtain essential nutrients in hostile environments is a critical skill for pathogens. Under zinc-deficient conditions, Pseudomonas aeruginosa expresses a pool of metal homeostasis control systems that is complex compared with other Gram-negative bacteria and has only been partially characterized. Here, the structure and zinc-binding properties of the protein PA4063, the first component of the PA4063-PA4066 operon, are described. PA4063 has no homologs in other organisms and is characterized by the presence of two histidine-rich sequences. ITC titration detected two zinc-binding sites with micromolar affinity. Crystallographic characterization, performed both with and without zinc, revealed an α/β-sandwich structure that can be classified as a noncanonical ferredoxin-like fold since it differs in size and topology. The histidine-rich stretches located at the N-terminus and between β3 and β4 are disordered in the apo structure, but a few residues become structured in the presence of zinc, contributing to coordination in one of the two sites. The ability to bind two zinc ions at relatively low affinity, the absence of catalytic cavities and the presence of two histidine-rich loops are properties and structural features which suggest that PA4063 might play a role as a periplasmic zinc chaperone or as a concentration sensor useful for optimizing the response of the pathogen to zinc deficiency

Subcutaneous insulin infusion (CSII) in italy: The third national survey

Continuous subcutaneous insulin infusion (CSII) is increasingly being used worldwide, mostly thanks to technical improvements. This study examined the current status of CSII in Italy. Physicians in charge of 272 diabetes centers caring for patients using CSII were sent a questionnaire investigating clinical features, pump technology and management of these patients; a large proportion (217 centers, 79.8%) joined the study. By end-April 2013, data had been collected on 10152 patients treated with CSII; 98.2% had type 1 diabetes, 82.4% were adults, 57% female. Only just over half the centers (59%) managed more than 20 CSII patients each. The distribution of patients varied widely both among and within different regions. The main indication for CSII was the de- sire to improve glycemic control. Dropouts (8.65%) were mainly due to difficulties with pump wearability or non-optimal glycemic control. Among CSII patients 61% used a traditional pump, 39% a sensor augmented pump. Only 68% used the CSII advanced functions and glucose sensors were used twelve days per month on average. Round-the-clock assistance was guaranteed in 81% of centers; a full diabetes team followed patients in only 40% of adult-care centers and 50% of pediatric units. CSII is increasingly used in Italy, by adults and pediatric patients. However, further work is needed to unify treatment strategies throughout the country and to encourage optimal pump use and applications