495 research outputs found
The seaweed Chaetomorpha linum cultivated in an integrated multitrophic aquaculture system: A new tool for microplastic bioremediation?
No full textMicroplastics (MPs) are emerging pollutants with detrimental impacts on ecosystems and human health. Due to their adverse effects, new strategies to mitigate MP pollution in the marine environment need to be developed urgently. In this context, the capability of the seaweed Chaetomorpha linum (Chlorophyta, Cladophorales) to trap MPs, as well as the effectiveness of a simple washing procedure to clean up the harvested seaweed biomass, were investigated. This algal species was grown in an integrated multitrophic aquaculture system (IMTA), where bioremediator organisms such as macroalgae, polychaetes, sponges and mussels were farmed in the vicinity of the fish cages. MPs trapped in C. linum were classified based on shape and size, and representative samples of each shape were analysed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to evaluate their chemical composition. Fibre MPs were the most abundant (97.3 %), while the size ranged from 0.025 to 2.00 mm, with most samples being in the size range 0.80-1.00 mm. MPs were composed mainly of polypropylene, polystyrene, and polyethylene. They were efficiently removed from the cultured seaweeds by a simple density separation procedure, consisting of three extractions with hypersaline solutions of sodium chloride. These results suggest that C. linum cultivated in an IMTA system can be proposed as a bioremediator to capture MPs from the surrounding environment. At the same time, harvested and cleaned green seaweeds may be considered a co-product of the bioremediation process and can find application in several biotechnological fields, including the use as a food source for human consumption
Spectral and kinetic properties of semiquinones in bacterial photosynthetic reaction centres embedded in liposomes obtained by different phospholipids
No full textTips for a (simple) interpretation of the impedance response of an electrochemical cell
No full textIn electrochemical experiments much of information is enclosed in the impedance response. It is usually represented by means of an equivalent electrical circuit, whose elements are able to describe the most general physico-chemical phenomena which characterize the system. To this aim, some standard circuits have been designed and commercial software is available to perform the best fit of the experimental data. However, the search of the most appropriate equivalent circuit is sometimes not a simple task due to experimental constraints and also due to a limited knowledge of the phenomenon. Therefore, a blind fitting procedure could give unsatisfactory results. Graphical representations of impedance, in particular the phase plot, offer useful tips in guessing the most appropriate equivalent circuit and estimating the values of the circuit parameters. Here we present a procedure in three steps: a. the analysis of some graphical representations of impedance for the selection of a suitable equivalent circuit, b. the formulation of a minimal set of equations useful for guessing the circuit parameters; c. a numerical test. An application to a set of data referring to quite different experimental conditions complete the study
Heavy metal ion influence on the photosynthetic growth of Rhodobacter sphaeroides
No full textThe potential of purple non-sulphur bacteria for bioremediation was assessed by investigating the ability of Rhodobacter sphaeroides strain R26.1 to grow photosynthetically in heavy metal contaminated environments. Bacterial cultures were carried out in artificially polluted media, enriched with the transition metal ions Hg2+, Cu2+, Fe2+, Ni2+, Co2+, MoO42-, and CrO42- in millimolar concentration range. For each investigated ion the effect on growth parameters was evaluated. The analysis of concentration-effect curves revealed a differentiated response, indicating that diverse mechanisms of tolerance and/or resistance are involved. Adaptation or selection procedures were not applied, leading to assess intrinsic abilities of coping with these contaminants. The microorganism proved to be highly tolerant to heavy metal exposure, especially towards Co2+, Fe2+ and MoO42-. In addition Ni2+ and Co2+ were found to decrease the cellular content of light harvesting complexes. A characteristic behavior was observed with mercuric ions, which produced a significant increase of the lag-phase. (c) 2005 Elsevier Ltd. All rights reserved
DEVELOPMENT AND CHARACTERIZATION OF A NOVEL ANTIBACTERIAL MATERIAL BASED ON GOx IMMOBILIZED IN A PVA FILM
No full textLiposomes containing nanoparticles: preparation and applications
No full textThe impetuous development of nanotechnology over the past two decades has enabled the production of a plethora of nanomaterials with outstanding optical, magnetic, electrical, catalytic and mechanical properties. The versatility of these materials attracted attention from the very beginning in the most disparate sectors of science and technology. The application of nanomaterials in the biological and biomedical fields soon benefited from the interaction with liposomes, which increased their biocompatibility and biostability. Liposomes indeed are versatile self-assembling supramolecular (nano)structures constituted of an aqueous core enclosed by a lipid bilayer, able to host hydrophobic and hydrophilic cargo, and with superior biocompatibility and great similarity with the biological membranes. The result is the construction of hybrid nanoscale architectures, in which nanoparticles (NPs) are allocated either in the aqueous core, in the palisade of the lipid bilayer or on the outer surface of the vesicles. In the first part of this review, the principal methods for the preparation of NP-loaded liposomes are carefully illustrated in a tutorial manner. In the second part, an overview of the great potentialities deriving from the conjugation of liposomes with NPs is presented. In each paragraph, the main characteristics of the most notable classes of NPs, the related issues, and the advantages arising from their association with liposomes are shown. Here, the most significant research works in literature for each kind of system are presented
ADSORPTION OF PROTEOLIPOSOMES AT THE AIR-WATER INTERFACE AS A TOOL FOR THE PREPARATION OF SUPPORTED PHOTOACTIVE MEMBRANES
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