Search results for "Gradation"
showing 10 items of 1275 documents
Biodegradation of Crude Oil by Individual Strains and a Mixed Bacterial Consortium in Simulation of Marine Environment
2013
Petroleum hydrocarbons are the most widespread contaminants in the marine environment. The fate of petroleum in sea water is largely controlled by mechanical, physical and chemical factors which influencing the natural transformation of petroleum (oil weathering) and oil bio-degradation. On the basis of these considerations, bioremediation techniques have been developed and improved for cleaning up oil-polluted marine environment as alternative to chemical and physical techniques. To elucidate the cooperative action of mixed microbial populations in the biodegradation of crude oil, we constructed artificial consortia composed of two to three bacteria (Alcanivorax borkumensis strain SK2, Rho…
Intrinsic bioremediation potential of a chronically polluted marine coastal area.
2015
A microbiological survey of the Priolo Bay (eastern coast of Sicily, Ionian Sea), a chronically polluted marine coastal area, was carried out in order to discern its intrinsic bioremediation potential. Microbiological analysis, 16S rDNA-based DGGE fingerprinting and PLFAs analysis were performed on seawater and sediment samples from six stations on two transects. Higher diversity and variability among stations was detected by DGGE in sediment than in water samples although seawater revealed higher diversity of culturable hydrocarbon-degrading bacteria. The most polluted sediment hosted higher total bacterial diversity and higher abundance and diversity of culturable HC degraders. Alkane- an…
Uptake and photoinduced degradation of phthalic acid esters (PAEs) in Ulva lactuca highlight its potential application in environmental bioremediation
2022
Abstract The bioaccumulation of phthalates was studied in fragments of Ulva lactuca exposed for a maximum of 31 days at different concentrations of a solution of six phthalic acid esters (PAEs). The algal matrix showed rapid uptake since the first sampling, which increased over the time of the experimental period, at the end of which seaweed’s bioaccumulation potential was also evaluated. After the uptake, the algal matrix was subjected to UV irradiation in order to verify the removal of the phthalates. PAEs with higher octanol–water partition coefficients (logKow) and molecular weights were preferentially uptaken by U. lactuca in all the exposure experiments. It was observed that both accu…
Sustainable management systems to prevent and adaptat to desertification: Case Studies from the LIFE Desert Adapt project
2021
Around 40% of the ice-free terrestrial surface is under desertification risk, and the Mediterranean is one of the most sensible regions. Concomitantly, most areas occupied by agriculture suffer from lack of organic matter in the soil, as well as very low tree cover, making them more vulnerable to climate change. The LIFE (Desert Adapt) project aims to develop a desert adaptation model to enhance resistence and resilience of farms, both public and private, to desertification by appliyng an integrative sustainable land management in Italy, Spain and Portugal. In Italy three sites in Sicily are involved, two private areas in Caltanissetta and Catagirone and the municiaplity of Lampedusa.The mo…
Evaluation of benefits and limitations of a Desertification Adaptation Model framework for sustainable land management in areas under desertification…
2022
The LIFE project Desert-Adapt (LIFE16 CCA/IT/000011) has designed a Desertification Adaptation Model (DAM) framework of land management to respond to two of the most critical problems experienced by farmers, public land and communities of the Mediterranean Basin, given the need to adapt to current Climate Change and reduce or counteract the increasing phenomenon of land degradation and desertification risk. These two issues are interrelated, as land degradation often characterizes fragile areas where the co-occurrence of climatically unfavourable conditions, mostly prolonged aridity and high temperatures, and inappropriate land management, leads to loss of ecosystem quality, biodiversity, p…
RNA quality control: RppH activity allows selective removal of nonsense messages in E. coli.
2009
Polar effect, the reduced expression level of sequences downstream to mutations reducing translation efficiency, is usually due to transcription termination or inefficient translation reinitiation. Untranslated mRNAs are known to be quickly degraded, probably because of their increased accessibility to degradative enzymes due to the absence of translating ribosomes. In III-VI-I operon of phage f1, a strong polar effect is observed in a gIII 5’ proximal nonsense mutant, resulting in a very fast, RNaseE mediated, degradation of any full-length mRNA. RNaseE is a key component of the E. coli degradosome, the major RNA processing/degrading machinery. Its endonucleolytic activity is strongly enha…
Hydrocarbon degrading bacteria vs microbial consortia in the degradation of Policyclic Aromatic Hydrocarbons
2014
The Harbor of Priolo Gargallo is a chronically polluted area in Sicily (Italy). Bioremediation is an alternative friendly strategy to reduce environmental risks that relies on microorganisms that play a key role in the biodegradation of hydrocarbon contaminants. In this study, sediment samples were collected in 6 stations inside the area indicated. Analysis of total hydrocarbons, microbial abundance (DAPI, CFU and MPN), and total bacterial diversity (DGGE) were carried out. Enrichment cultures and isolation of hydrocarbon-degrading bacteria were carried out in the mineral medium ONR7a with a mix of Polycyclic Aromatic Hydrocarbons [PAHs-Mix; Methylnaphtalene, Byphenile, Phenantrene, Dibenzo…
Magnetic hybrid nanomaterials for the photodegradation of microcontaminats in aqueous environment
2018
Bio-based substances (BBS) isolated from urban biowaste have been employed to prepare hybrid magnetic nanomaterials with iron oxides. Such materials have been tested, in the presence of hydrogen peroxide, for the light induced photodegradation of four microcontaminants (MCs) in aqueous environment: Carbamazepine (C, an anticonvulsant and analgesic drug), Flumequine (F, an antibiotic), Ibuprofen (I, a non-steroidal anti-inflammatory drug), and Sulfamethoxazole (S, an antibiotic). Preliminary photodegradation experiments were carried out at lab-scale in a solar simulator, whereas optimized experiments were carried out in a pilot plant under natural solar radiation. The MCs complete abatement …
Safety assessment in N-M-V interaction of prestressed concrete elements subject to degradation of the reinforcements
2021
The estimation of residual life of viaducts and bridges is urgently topical, due to the age of Italian infrastructure network. Among the causes of reduced life of prestressed concrete structures, the role played by corrosion in prestressed reinforcements is fundamental. In fact, the reduction of the reinforcement cross-section with the formation of the outer layer of iron oxides and hydroxides and the bad filling of the ducts, induces an intermediate behaviour between that of external (unbonded) and internal (bonded) prestressing. For these reasons, the evaluation of degradation and its influence on structural safety cannot be neglected in the assessment of sections of existing structures c…
Degradation and rehabilitation of Gerber saddles of concrete bridges
2022
In recent decades, many concrete bridges, built in the 60s and 70s of the 20th Century with a Gerber-girder scheme, show severe damage of the saddles due to concrete degradation and reinforcement corrosion. On the basis of the recent Ministerial Guidelines for the assessment of existing bridges, it is necessary to evaluate the state of the Gerber saddles in a large number of bridges on both main and secondary roads. To do this, it is necessary to apply flexible assessment procedures that can be adapted to several situations and that allow a speedy assessment of the intervention priorities. The methodologies of intervention represent the crucial point for a rapid rehabilitation of these infr…