2,050 research outputs found

    3,4,5,3’,5’-pentabromo-2-(2’-hydroxybenzoyl) pyrrole: a potential lead compound as anti Gram-positive and anti biofilm agent

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    The activity against Gram-positive bacteria of 3,4,5,3 ,5 -pentabromo-2-(2 -hydroxybenzoyl)pyrrole I, a synthetic anti-bacterial compound related to pyrrolomycins, was tested in vitro using seven reference bacterial strains and Staphylococcus epidermidis and Staphylococcus aureus preformed biofilms. Compound I was active against all strains tested, with minimum inhibitory concentration (MIC) values ranging from 0.002 to 0.097 mg/l and minimum bactericidal concentrations (MBCs) from 0.37 to 12.5 mg/l. Compound I was also active at low concentrations against preformed S. epidermidis and S. aureus biofilms

    Fragments of -thymosin from the sea urchin Paracentrotus lividus as potential antimicrobial peptides against staphylococcal biofilms

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    The immune mediators in echinoderms can be a potential source of novel antimicrobial peptides (AMPs) applied toward controlling pathogenic staphylococcal biofilms that are intrinsically resistant to conventional antibiotics. The peptide fraction <5 kDa from the cytosol of coelomocytes of the sea urchin Paracentrotus lividus (5-CC) was tested against a group of Gram-positive and Gram-negative pathogen reference strains. The 5-CC of P. lividus was active against all planktonic-tested strains but also showed antibiofilm properties against staphylococcal strains. Additionally,wedemonstrated the presenceof three smallpeptides in the5-CCbelonging tosegment 9-41of aP. lividus -thymosin. The smallest of these peptides in particular, showed the common chemical\u2013physical characteristics of AMPs. This novel AMP from -thymosin has high potential activity as an antibiofilm agent, acting on slow-growing bacterial cells that exhibit a reduced susceptibility to conventional antibiotics and represent a reservoir for recurrent biofilm-associated infections

    Analysis of the influence of tectonics on the evolution of valley networks based on Srtm Dem, Jemma River basin, Ethiopia

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    The Ethiopian Highlands are a good example of a high plateau landscape formed by a combination of tectonic uplift and episodic volcanism. Deeply incised gorges indicate active fluvial erosion, which leads to instabilities of over-steepened slopes. In this study we focus on the Jemma River basin, which is a left bank tributary of the Abay - Blue Nile in order to assess the influence of neotectonics on the evolution of its river and valley network. Tectonic lineaments, shape of valley networks, direction of river courses and intensity of fluvial erosion were compared in six subregions, which were delineate beforehand by means of morphometric analysis. The influence of tectonics on the valley network is low in the older deep and wide canyons and on the high plateau covered with Tertiary lava flows, whilst in the younger upper part of the canyons it is high. Furthermore, the coincidence of the valley network with the tectonic lineaments differs in the subregions. The direction of the fluvial erosion along the main tectonic zones (NE-SW) made it possible for backward erosion to reach far distant areas in the east. This tectonic zone also separates older areas in the west from the youngest landscape evolution subregions in the east, next to the Rift Valley

    De novo design of antimicrobial and antibiofilm peptides starting from desert truffle Tirmania pinoyi peptides

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    With the aim of discovering new routes in the research of antimicrobials, we focused on polypeptide- enriched extracts derived from edible desert truffle mushroom Tirmania pinoyi. The extracts showed an interesting activity with MIC=50 μg/mL against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. Through mass spectrometry analysis (RP-HPLC/ nESI-MS/MS) the following eight novel peptides FDVVPKTAANFRAL, AVTVGASTLADERA, FLVGGASLKPEF, VARIFAVFNDTF, HLVDEPQNLLK, LGEYGFQNALLR, FAVNGGCAKET, SREDLHPKL were detected. To characterize them online websites were used: IAMPpred, DPBAAS, Cell-PPD, ToxinPred, HemoPI, PeptideCutter and HLP. The analysis indicated that some peptides showed negative or neutral charge, hydrophobic ratio between 42% and 67%, Boman Index &lt; 2.25 kCal/mol. According to the “APD3: Antimicrobial Peptide Calculator and Predictor” tool of the Antimicrobial Peptide Database (APD) similarities (around 30-40%) with known antimicrobial peptides (AMPs) identified in amphibians were also detected. In contrast, the predicted antimicrobial, antifungal and antibiofilm activity was not significant. In order to improve biological and physico-chemical properties, the sequences of natural peptides were modified using APD3, by replacing some hydrophilic and negative charged amino acids with hydrophobic and positive ones. The derivative sequences (GWDVVPKTWWKFRAL, KWTWGASTLAKKRA, FLRGGWSLKPKF, KWRIFWVFNKTF, HLVKRWQNLLK, KGKYRFWNALLR, FARWGGCAKRT, SRKWLHPWL) showed net positive charge between +2 and +4, hydrophobic ratio between 42% and 48%, Boman Index &lt; 2.25 kCal/mol and high stability. Moreover, the predicted antimicrobial, antifungal and antibiofilm activity was high, without toxic or hemolytic effects. In conclusion, bioinformatic analysis has demonstrated that novel peptides discovered in T. pinoyi may be considered new platforms for the design of novel antimicrobial and antibiofilm peptides to counteract multi-drug resistant pathogens

    A High Sensitive Nested PCR for Toxoplasma gondii Detection in Animal and Food Samples

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    Toxoplasma gondii is a major food and waterborne transmitted parasite world-wide. The tissues and meat samples of many warm blooded animals can contain tissues cysts from chronic toxoplasmosis. Water and vegetable can be contaminated by the parasitic oocysts shed through the feces of infected cats, representing the definitive host of the parasite. A sensitive PCR for Toxoplasma gondii detection is described. The first step amplified the region between the 28S and 18S rDNA in the closely related T. gondii and Neospora caninum; RFLP analysis distinguished the DNA from the two morphologically identical parasites. Although N. caninum is not involved in human transmission, so far, it is important for animal health since is a major responsible for abortion in cattle. The nested PCR was used in a dilution assay in pork sausage samples spiked with T. gondii parasitic DNA. The analysis showed that up to 200fg equivalent to two single parasites only, could be detected. Similar detection limit for T. gondii can be obtained with real-time PCRs, but real time methods need special consumables and expensive equipment

    MGMT promoter methylation and IDH1 mutations do not affect [18F]FDOPA uptake in primary brain tumors

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    The aim of our study was to investigate the effects of methylation of O-6-methylguanine-DNA methyltransferase promoter (MGMTp) and isocitrate dehydrogenase 1 (IDH 1) mutations on amino acid metabolism evaluated with 3,4-dihydroxy-6-[F-18]-fluoro-l-phenylalanine ([F-18] FDOPA) positron emission tomography/computed tomography (PET/CT). Seventy-two patients with primary brain tumors were enrolled in the study (33 women and 39 men; mean age 44 +/- 12 years old). All of them were subjected to PET/CT examination after surgical treatment. Of them, 29 (40.3%) were affected by grade II glioma and 43 (59.7%) by grade III. PET/CT was scored as positive or negative and standardized uptake value ratio (SUVr) was calculated as the ratio between SUVmax of the lesion vs. that of the background. Statistical analysis was performed with the Mann-Whitney U test. Methylation of MGMTp was detectable in 61 out of the 72 patients examinated. Mean SUVr in patients without methylation of MGMTp was 1.44 +/- 0.38 vs. 1.35 +/- 0.48 of patients with methylation (p = 0.15). Data on IDH1 mutations were available for 43 subjects; of them, 31 are IDH-mutant. Mean SUVr was 1.38 +/- 0.51 in patients IDH mutant and 1.46 +/- 0.56 in patients IDH wild type. MGMTp methylation and IDH1 mutations do not affect [F-18] FDOPA uptake in primary brain tumors and therefore cannot be assessed or predicted by radiopharmaceutical uptake parameters
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