ENDOSYMBIONTS OF ENTOMOPATHOGENIC NEMATODES FROM SOUTH ITALY:A PHENOTYPIC STUDY

We examined different Xenorhabdusstrains (five of X. bovieniiand two of X. kozodoii), obtained from EPNisolates belonging to the genus Steinernema(S. feltiae, S. ichnusae, S. apuliae, S. vulcanicum) of different geographicorigin by both genotypic and phenotypic analysis. Common laboratory assays were done for traits such as antibioticresistance, haemolytic activity, lactose utilisation, biofilm production, chosen as the least selectable traits for EPN life-cycle, and thus as (presumably) neutral traits. As selective marker, the activity of the endosymbiont’s toxins was verified inan in vivoassay on G. mellonellalarvae. Genotyping done by 16S partial sequencing was used for identification purposes.Xenorhabdusbovieniiisolates showed a broad phenotypic spectrum; on the other hand, X. kozodoiishowed a less degreeof phenotypic variation, reduced ability of biofilm production and conspicuous β-galactosidase activity. However, all thestrains were able to kill G. mellonellalarvae with high efficiency

Renal Insufficiency in Non-Diabetic Subjects: Relationship of MTHFR C677t Gene Polymorphism and Left Ventricular Hypertrophy

Association of methylenetetrahydrofolate reductase (MTHFR) 677CT gene polymorphism with hyperhomocysteinemia, renal failure, and cardiovascular events is controversial. We investigated the relationship of MTHFR 677CT polymorphisms with left ventricular hypertrophy (LVH) and renal insufficiency.Glomerular filtration rate (GFR) and left myocardial ventricular mass/m2 were assessed in 138 non-diabetic subjects (age, 50.93 ± 14.85 years; body mass index, 27.95 ± 5.98 kg/m(2)), 38 no-mutation wild MTHFR C677CC, 52 heterozygous MTHFR C677CT, and 48 homozygous MTHFR C677TT, all with adequate adherence to current international healthy dietary guidelines. Serum homocysteine, insulin resistance, high-sensitivity C-reactive-protein (hsCRP), parathyroid hormone, and renal artery resistive index (RRI) were challenged by odds ratio analysis and multiple linear regression models.MTHFR 677CT polymorphism showed higher GFR (73.8 ± 27.99 vs. 58.64 ± 29.95; p= 0.001) and lower renal failure odds (OR, 0.443; 95% confidence interval, 0.141-1.387) in comparison with wild MTHFR genotype. A favorable effect on GFR of MTHFR polymorphism is presented independently by the negative effects of LVH, increased intra-renal arterial resistance, and hyperparathyroidism; GFR is the significant predictive factor to LVH.Renal insufficiency in non-diabetic subjects is explained by interactions of MTHFR C677T polymorphism mutation with LVH, hsCRP, intact parathyroid hormone (iPTH), and RRI. Sign of these predictive effects is opposite: subjects with MTHFR 677CT polymorphism have lower likelihood of renal insufficiency; differently, wild-type MTHFR genotype subjects have lower GFR and greater hsCRP, iPTH, RRI, and LVH

Effect of the surface morphology of TiO2 nanotubes on photocatalytic efficacy using electron-transfer-based assays and antimicrobial tests

The application of titanium oxide nanotubes for the removal of contaminants from freshwater is a rapidly growing scientific interest, especially when it comes to water conservation strategies. In this study we employed four different titanium oxide nanotube surfaces, prepared by a two-electrode anodic oxidation. Two of the surfaces were synthesised in aqueous media, while the other two surfaces were synthesised in ethylene glycol. One of the arrays synthesised in the organic medium was impregnated with silver nanoparticles, while the remaining surfaces were not. The chemical reactivity of the various surfaces was assessed using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as free electron sensitive probe molecules, in parallel with tannic acid degradation and copper ion reducing capacity. The potential antimicrobial activity of the surfaces was assessed against a panel of microorganisms composed of yeast, fungi, Gram-positive and Gram-negative bacteria. Field emission scanning electron microscopy revealed that surfaces produced in the aqueous medium had a smaller tube length and a smaller tube diameter. It was noted that one of the materials using sodium sulfate as the supporting electrolyte had the most irregular nanostructure morphology with tubes growing to the side rather than vertically. The structural variation of the surfaces directly reflected both the chemical and biological activity, with the nanotubes formed in ethylene glycol showing the fastest rates in the stabilization of DPPH and ABTS radicals, the fastest tannic acid decomposition under various pH conditions and the fastest metal reducing activity. Furthermore, the surface containing silver and its bare counterpart showed the most effectivepeer-reviewe

Suitability of different titanium dioxide nanotube morphologies for photocatalytic water treatment

Photocatalysis has long been touted as one of the most promising technologies for environmental remediation. The ability of photocatalysts to degrade a host of different pollutants, especially recalcitrant molecules, is certainly appealing. Titanium dioxide (TiO2) has been used extensively for this purpose. Anodic oxidation allows for the synthesis of a highly ordered nanotubular structure with a high degree of tunability. In this study, a series of TiO2 arrays were synthesised using different electrolytes and different potentials. Mixed anatase-rutile photocatalysts with excellent wettability were achieved with all the experimental iterations. Under UVA light, all the materials showed significant photoactivity towards different organic pollutants. The nanotubes synthesised in the ethylene glycol-based electrolyte exhibited the best performance, with near complete degradation of all the pollutants. The antibacterial activity of this same material was similarly high, with extremely low bacterial survival rates. Increasing the voltage resulted in wider and longer nanotubes, characteristics which increase the level of photocatalytic activity. The ease of synthesis coupled with the excellent activity makes this a viable material that can be used in flat-plate reactors and that is suitable for photocatalytic water treatment.peer-reviewe

Ag/ZnO/PMMA nanocomposites for efficient water reuse

This work attempts to produce photocatalytic surfaces for large-scale applications by depositing nanostructured coatings on polymeric substrates. ZnO/poly(methyl methacrylate) (PMMA) composites were prepared by low-temperature atomic layer deposition (ALD) of ZnO on PMMA substrates. In addition, to increase the photocatalytic and antibacterial activities of ZnO films, Ag nanoparticles were added on ZnO surfaces using plasma-enhanced ALD. The morphology, crystallinity, and chemical composition of the specimens were meticulously examined by scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses. The noteworthy photocatalytic activity of the nanocomposites was proved by the degradation of the following organic pollutants in aqueous solution: methylene blue, paracetamol, and sodium lauryl sulfate. The antibacterial properties of the samples were tested using Escherichia coli as a model organism. Moreover, the possible toxic effects of the specimens were checked by biological tests. The present results unambiguously indicate the Ag/ZnO/PMMA nanocomposite as a powerful tool for an advanced wastewater treatment technology.peer-reviewe

Silicon calorimeter for cosmic antimatter search

Abstract The silicon sampling calorimeter presented is conceived as a fine grained imaging device to carry out studies of the anti-matter component in the primary cosmic radiation; it will be used in balloon payload program starting in 1993. The first sampling layer (48×48 cm2) of this silicon calorimeter has been completed and successfully tested. We report the first results form studies performed at the CERN PS t7 beam. The complete calorimeter contains 20 xy sampling layers (strip pitch 3.6 mm) interleaved with 19 showering material planes (tungsten 0.5 X0). This allows to picture the transverse distributions of the shower in both coordinates at each sampling. The outstanding imaging capabilities reflects in high particle identification power. Preliminary results from beam tests performed with antiprotons at 3.5 GeV on a tower prototype of the calorimeter are reported

L'interférence par l'ARN dans les cellules de mammifère

L'interférence par l'ARN est le premier exemple d'une régulation par des petits ARN dont le mécanisme ait été analysé en détail. L'observation de départ faite chez C. elegans est que des ARN double brin peuvent induire la dégradation d'ARN messagers qui contiennent les mêmes séquences. Le mécanisme comprend deux étapes principales, la coupure des ARN double brin en petits fragments d'une vingtaine de nucléotides, les ARN interférents, et l'incorporation de ces petits ARN dans un complexe protéique. Dans le cas de l'interférence telle qu'elle a été initialement décrite, une protéine (argonaute 2 chez les mammifères) et un petit ARN sont suffisants pour créer une endonucléase spécifique de séquence. Comme cette nucléase n'est active que sur des substrats qui ont une séquence complémentaire de celle du petit ARN qui sert de guide, on dispose donc d'un outil idéal pour inhiber l'expression de tout gène dont on connaît la séquence. Cependant, plusieurs aspects limitent l'efficacité et la spécificité de cette approche. En particulier il n'est pas possible de séparer cette activité de dégradation des ARN messagers d'autres activités de régulation des petits ARN qui pour certaines ne possèdent pas le même degré de spécificité de séquence. Seule une meilleure compréhension des mécanismes en cause permettra, si c'est possible, d'obtenir l'outil idéal capable d'induire une extinction (silencing) efficace et spécifique

Toxic effects caused by a long-term exposure of Danio rerio to TiO2 nanoparticles.

In the last years, metal oxide nanoparticles (NPs) are receiving increasing attention due to their different applications. NPs have unique physicochemical properties that differ substantially from their respective bulk materials of the same composition. According to several studies, titanium dioxide (TiO2) nanoparticles (NPs) have short-term risks on Danio rerio (zebrafish). In the present study, we focus on the potential toxic effects that can be caused by a long-term exposure to titanium dioxide (TiO2) nanoparticles (NPs) on zebrafish. The zebrafish, has long been recognized as a useful model organism in ecotoxicology. Zebrafish Wild-type AB strains, were obtained from the Sicilian Center of Experimental Ichthyiopathology (CISS), University of Messina, Italy, where they were kept in a "Fish facilities" (Stand Alone Unit, Tecniplast), a closed-loop system for the continuous monitoring of vital parameters. Adult specimens of zebrafish were exposed to different concentrations of TiO2 NPs (0,5-1 mg/L) (Degussa P25, Sigma Aldrich), for 90 days. Histological, immunohistochemical and molecular analysis were performed on their gills, gut, skin, muscles and liver. All samples analyzed by immunohistochemical investigation, showed a very clear positive response to Metallothioneins (Abcam, 1:500). Moreover, the positivity was confirmed by Western blot analysis (WB). Histological examination showed intestinal alterations and in particular, partial thinning of the folds and occasional flaking of epithelium and morpho-functional alterations in the gill epithelium. Histological analysis on muscles, liver and skin showed no alterations. In conclusion, the current study confirmed only a slight cytotoxicity of TiO2 NPs on zebrafish adults after a long-term exposure, however, further and wider studies are required to establish their effects on other organs and to evaluate the severity of their toxicity

Endosymbionts of entomopathogenic nematodes from south Italy: A phenotypic study

We examined different Xenorhabdus strains (five of X. bovienii and two of X. kozodoii), obtained from EPN isolates belonging to the genus Steinernema (S. feltiae, S. ichnusae, S. apuliae, S. vulcanicum) of different geographic origin by both genotypic and phenotypic analysis. Common laboratory assays were done for traits such as antibiotic resistance, haemolytic activity, lactose utilisation, biofilm production, chosen as the least selectable traits for EPN life-cycle, and thus as (presumably) neutral traits. As selective marker, the activity of the endosymbiont’s toxins was verified in an in vivo assay on G. mellonella larvae. Genotyping done by 16S partial sequencing was used for identification purposes. Xenorhabdus bovienii isolates showed a broad phenotypic spectrum; on the other hand, X. kozodoii showed a less degree of phenotypic variation, reduced ability of biofilm production and conspicuous ?-galactosidase activity. However, all the strains were able to kill G. mellonella larvae with high efficiency