4,712 research outputs found

    PHK from phenol hydroxylase of Pseudomonas sp. OX1. Insight into the role of an accessory protein in bacterial multicomponent monooxygenases

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    Bacterial multicomponent monooxygenases (BMMs) are members of a wide family of diiron enzymes that use molecular oxygen to hydroxylate a variety of aromatic compounds. The presence of genes encoding for accessory proteins not involved in catalysis and whose role is still elusive, is a common feature of the gene clusters of several BMMs, including phenol hydroxylases and several soluble methane monooxygenases. In this study we have expressed, purified, and partially characterized the accessory component PHK of the phenol hydroxylase from Pseudomonas sp. OX1, a bacterium able to degrade several aromatic compounds. The phenol hydroxylase (ph) gene cluster was expressed in Escherichia coli/JM109 cells in the absence and in the presence of the phk gene. The presence of the phk gene lead to an increase in the hydroxylase activity of whole recombinant cells with phenol. PHK was assessed for its ability to interact with the active hydroxylase complex. Our results show that PHK is neither involved in the catalytic activity of the phenol hydroxylase complex nor required for the assembly of apo-hydroxylase. Our results suggest instead that this component may be responsible for enhancing iron incorporation into the active site of the apo-hydroxylase

    Trace metal distributions in Posidonia oceanica and sediments from Taranto Gulf (Ionian Sea, Southern Italy)

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    Distribution of metals (Hg, Pb, Sn, Cu, Cd and Zn) was determined in sediments and in different tissues of Posidonia oceanica collected from San Pietro Island, Taranto Gulf (Ionian Sea, Southern Italy). In seagrass, results, compared with metal concentrations in sediments, showed that the highest concentrations of Hg, Pb, Sn and Cu were found in the roots, while in the green leaves were found the highest levels of Cd and Zn. Instead the lowest metal concentrations were found in the basal part of the leaf. Levels of  metals in the leaves were similar to those found by other authors in uncontaminated areas of the Mediterranean Sea. Mercury levels in roots were correlated to levels in sediments. This could demonstrate the plant memorizes sediments contamination . This study reinforces the usefulness and the relevance of Posidonia oceanica as an indicator of spatial metal contamination and an interesting tool for environmental quality evaluation

    Heavy metals monitoring in mussels Mytilus galloprovincialis from the Apulian coasts (Southern Italy)

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    Concentrations of six heavy metals (Cd, Cr, Cu, Hg, Pb and Zn) and one semi-metal (As) were determined in tissues of mussels Mytilus galloprovincialis collected along the Apulian coasts (Mediterranean sea). This project, performed in 2009, was targeted toward the assessment of levels and spatial distribution of metals in the environment in order to evaluate the coastal water quality using mussels as bioindicators and health risk for mussel consumers.The concentrations (mg/kg d.w.) of these metals ranged from 6.35 to 76.17 for arsenic (As), 0.38 to 2.54 for cadmium (Cd), 0.96 to 9.46 for chromium (Cr), 5.26 to 19.22 for copper (Cu), 0.10 to 0.81 for mercury (Hg), 25.00 to 110.51 for zinc (Zn) and from 0.37 to 3.25 for lead (Pb). These levels were lower than the permissible limits set by European Commission and FAO with the exception for Cr in three sampling stations. Evaluation of the risk associated to molluscs consumption for human health suggested that there is no evident risk for a moderate Mytilus g. consumer, however heavy metals concentrations must be monitored periodically and carefully with respect to the consumers health

    Safety of measles, mumps, and rubella vaccine in egg allergy: in vivo and in vitro management

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    Background: Egg allergy is the second most prevalent form of food allergy in childhood. In spite of the evidence accumulated, inoculating egg allergy children with attenuated vaccines grown on chick embryo cell cultures, such as the measles, mumps, and rubella (MMR) vaccine, is regarded (erroneously) as potentially dangerous or even anaphylactogenic, by many. An issue perceived as particularly conflicting also by Health Professionals. Case presentation: A 15-year-old boy, with a history of severe egg allergy in early infancy, who was still sensitized to egg allergens, including baked egg, had never received MMR vaccination, in fear of possible anaphylaxis, in spite of the fact that this vaccination is mandatory in the first year of life, in Italy. Because of that, he was not allowed to attend school, longer, and was referred to us in order to assess the potential risk of MMR vaccination. Upon thorough allergologic workup, sensitization to MMR vaccine components was excluded by an in vivo approach, consisting in skin prick tests, intradermal tests, and subcutaneous injection test, corroborated by vaccine-specific B-lymphocyte proliferation assay, ex vivo. T-cell proliferation in response to MMR vaccine was also excluded. Eventually, the boy was inoculated with MMR vaccine and was readmitted to school. Conclusions: The diagnostic strategy adopted appears feasible and easy-to-perform and may be adopted in controversial cases (as the one reported), characterized by previous severe allergic reactions to egg. The B-lymphocyte proliferation assay we developed may represent a useful and reliable tool not only in research but also in clinical practice

    Therapeutic sequences in patients with grade 1−2 neuroendocrine tumors (NET): an observational multicenter study from the ELIOS group

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    Purpose: Many different treatments are suggested by guidelines to treat grade 1−2 (G1−G2) neuroendocrine tumors (NET). However, a precise therapeutic algorithm has not yet been established. This study aims at identifying and comparing the main therapeutic sequences in G1−G2 NET. Methods: A retrospective observational Italian multicenter study was designed to collect data on therapeutic sequences in NET. Median progression-free survival (PFS) was compared between therapeutic sequences, as well as the number and grade of side effects and the rate of dose reduction/treatment discontinuation. Results: Among 1182 patients with neuroendocrine neoplasia included in the ELIOS database, 131 G1–G2 gastroenteropancreatic, lung and unknown primary NET, unresectable or persistent/relapsing after surgery, treated with ≄2 systemic treatments, were included. Four main therapeutic sequences were identified in 99 patients: (A) somatostatin analogs (SSA) standard dose to SSA high dose (n = 36), (B) SSA to everolimus (n = 31), (C) SSA to chemotherapy (n = 17), (D) SSA to peptide receptor radionuclide therapy (PRRT) (n = 15). Median PFS of the second-line treatment was not reached in sequence A, 33 months in sequence B, 20 months in sequence C, 30 months in sequence D (p = 0.16). Both total number and severity of side effects were significantly higher in sequences B and C than A and D (p = 0.04), as well as the rate of dose reduction/discontinuation (p = 0.03). Conclusions: SSA followed by SSA high dose, everolimus, chemotherapy or PRRT represent the main therapeutic sequences in G1−G2 NET. Median PFS was not significantly different between sequences. However, the sequences with SSA high dose or PRRT seem to be better tolerated than sequences with everolimus or chemotherapy
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