3,112 research outputs found
Letter from Alfredo Casella to Michel-Dmitri Calvocoressi, undated
No full textAn undated letter from Italian composer, pianist and conductor Alfredo Casella to French musicologist and critic Michel-Dmitri Calvocoressi
Letter from Alfredo Casella to Michel-Dmitri Calvocoressi, September 19, 1903
No full textA letter, dated September 19, 1903, from Italian composer, pianist, and conductor Alfredo Casella to French musicologist and critic Michel-Dmitri Calvocoressi
A possibile role of nirK in Rhizobium sullae HCNT1.
No full textIn response to a number of environmental stresses many bacterial species, including Vibrio
vulnificus, Sinorhizobium meliloti, Micrococcus luteus, Escherichia coli and Helicobacter pylori,
enter the viable-but-not-culturable (VBNC) status (McDougald et al., 1998). In this metabolic state
they lose their ability to grow on media that usually sustain them and undergo such physiological
and morphological changes as increased resistance to several physic and chemical factors, and
changes in protein and lipid content. The recent increasing use of specific fluorescent dyes such as
Syto 9, CTC (5-cyano-2,3-di-4-tolyl-tetrazolium chloride), AO (Acridine Orange), propidium
iodide, made possible a proper identification of viability and the metabolic state of microbes
(Basaglia et al. 1997).
Sinorhizobium meliloti 41, a rhizobium nodulating Medicago sativa, enters VBNC status in
liquid microcosms when O2 is depleted from the atmosphere of the incubation mixture (Toffanin et
al., 2000; Casella et al. 2001). Plasmid-borne, firefly-derived, luciferase gene (luc) was inserted and
stably inherited in Sinorhizobium meliloti 41 (pRP4-luc) as a reporter gene. The strain obtained, S.
meliloti 41 pRP4-luc and its parental strain, served as a model system for VBNC experiments both
in vitro and in soil samples.
Rhizobium sullae, formerly Rhizobium ’hedysari’, is a nitrogen fixing bacterium that induces
symbiotic nodule formation on the legume Hedysarum coronarium (Squartini et al., 2002). Strain
HCNT1, expressing a copper-containing nitrite reductase encoded by nirK, which is closely related
to nitrite reductases in true denitrifiers, enters the same VBNC status when oxygen is limiting, but
only when nitrite is present and converted to NO. Since HCNT1 cannot grow as a denitrifier and
inactivation of nirK only resulted in the loss of NO production (Toffanin et al, 1996), the hypothesis
that expression of nirK may induce the VBNC status has been investigated.
Therefore, a comparison between the two systems, S. meliloti and R. sullae, is presented in order
to verify the possible connection of nirK with the VBNC status.
McDougald D. et al. 1998. FEMS Microbiology Ecology 25: 1-9
Basaglia M. et al. 1997. In: The biotechnology and ecological interactions of microbial inoculants".
Granada, Spain. pp. 19-20
Toffanin A. et al. 2000. Biol. Fertil. Soils. 31 (6): 484-488
Casella S. et al. 2001. ISME-9, Amsterdam (The Netherlands), p. 191
Squartini A. et al. 2002. Int. J. Syst. Evol. Microbiol. 52: 1267-1276
Toffanin A. et al. 1996. Appl. Environ. Microbiol. 62 (11): 4019-402
Novel biotechnological approaches for utilizing carbon containing wastes to make high value products: the "ANIMPOL" Project
No full textA sustainable and value-added conversion of waste from slaughterhouses, rendering industry, and waste fractions of the biodiesel production is the aim of the project “Biotechnological conversion of carbon containing wastes for eco-efficient production of high added value products-ANIMPOL”.
ANIMPOL was founded by the Seventh Framework Programme (FP7) of the European Commission and the project has started on the 1st January 2010. The main objective is the development of an industrial process, that brings together the solution of industrial waste problems with essential alternative strategies for polymer industry. Waste streams from slaughterhouses are converted towards fatty acid esters (FAMEs, biodiesel). Subsequently the FAME fractions, that negatively influence the biodiesel properties as a fuel, are biotechnologically converted towards high-value polyhydroxyalkanoate (PHA) biopolymers. This brings together representatives of the waste producers from animal processing industry and bio-fuel industry with the polymer industry looking for alternatives technologies. Research will be done in close cooperation between academic and industrial partners and will last for 36 months. In addition to the meat processing plant Reistenhofer GesmbH and the Scottish biodiesel producer Argent Energy (UK) Limited, other industrial partners are the italian packaging manufacturer Termoplast and the german company Argus Environmental Biotechnology GmbH (responsible for the downstream processing). From the academic side TU Graz acts as project coordinator and expert on biotechnology (Prof. Braunegg). Prof. Narodoslawsky’s group from TU Graz is responsable for Life Cycle Assessment and Prof. Schnitzer’s group from the same university for the development of cleaner production processes. The group of Prof. Casella (University of Padova, Italy) will be on charge of the microbiology and genetics part and Prof. Horvat (University of Zagreb, Croazia) for the mathematical modeling of bioprocesses. The Karl-Franzens University Graz (Prof. Mittelbach) takes over the task of the optimized production of biodiesel from animal fats, while the University of Pisa (Prof. Chiellini), National the Institute of Chemistry (Ljubljana, Dr. Krzan) and the Polish Academy of Sciences (Prof. Kowalczuk) have specific tasks in the field of polymer characterization. Providing long-term strategies for long-term problems, the project will result in value creation for all players. The development of this integrated process will give results in microbiology, genetics, biotechnology, chemical engineering, polymer chemistry- and processing and life cycle analysis, combined with feasibility studies for marketing of the final products. The project activities aim at solving local waste problems affecting the entire EU; the solutions will be developed on local scales, but are meant to be applied to the entire EU and will provide cost-efficient and alternatives for polymer industry.
Information:
Prof. Sergio Casella, University of Padua, [email protected]
www.animpol.tugraz.a
Correction: The reaction of acetonitrile with hydrogen peroxide in alkaline medium: a DFT mechanistic study of green production of amides
No full textCorrection for 'The reaction of acetonitrile with hydrogen peroxide in alkaline medium: a DFT mechanistic study of green production of amides' by Girolamo Casella et al., Phys. Chem. Chem. Phys., 2023, https://doi.org/10.1039/d3cp02024j
Testimonianze epigrafiche per una sintesi sulla proprietá imperiale nel territorio riminese
No full textDon Angelo Bertasi, il suo tempo e la nostra epoca: alcune riflessioni antropologiche
No full textAnalisi antropologica dell'opera di Don Angelo Bertas
H-ZSM-5 Modified Zeolite: Quantum Chemical Models of Acidic Sites
No full textA ZSM-5 fragment, containing 52 tetrahedral moieties, each of them formed by one silicon or one aluminum atom surrounded by four oxygen atoms, was employed to model (52T systems) by quantum chemical calculations (i) the influence of the positions of the acidic sites on the energetics of 22 aluminum monosubstituted and bisubstituted 52T acidic zeolite (H-ZSM-5) systems and (ii) the local adsorption properties and acidic strength of the corresponding -OH sites. The energetics and the structural properties of simpler acid H-ZSM-5 systems containing only five Tetrahedral moieties (5T systems) were also modeled for comparison. B3LYP/6-31G(d,p) partial geometry optimization routines were performed on the 5T and 52T systems. On the latter, ONIOM(B3LYP/6-31G(d,p)jAM1) calculations and an alternative approach, i.e., the ONIOM method followed by a single-point at the above B3LYP/6-31G(d,p) level, aimed to decrease the need of computational resources, were also employed to analyze the properties of the different H-ZSM-5 models. The whole results showed that the orientation and the position of the acidic hydrogen atoms within the zeolite channel strongly affect the stability of the model systems, irrespective of the starting local topology characterizing the Al T Si substitution site. Bro ̈nsted gas-phase acidity strength and adsorption-ability were evaluated through the analysis of the energy involved in (i) the proton dissociation from the acidic sites and (ii) the cis-but-2-ene and trans-but-2-ene adsorption on the same acidic sites. Both were affected, although to a very different extent, by the location and number of the considered -OH acidic groups. In particular, 2 among the 12 modeled acidic sites resulted in a highly stabilized zeolite structure, pointing out that the Al T Si substitutions in the synthesis of aluminated ZSM-5 zeolites, and hence the corresponding catalytic activity, could preferentially occur on special sites. The choice of the computational method along with the size and the cutoff of the mimicked structures influenced the reliability of the calculations. The suggested alternative approach (that is, the ONIOM followed by the DFT single-point calculation) provided reasonable findings at very low computational cost
I microrganismi nella lotta biologica
No full textNonostante si faccia un gran parlare di salvaguardia della biodiversità, si
dimentica spesso che la prima, principale causa che ha sistematicamente
minato le risorse del nostro pianeta in termini di biodiversità è proprio l’agricoltura.
Da 8000 anni a questa parte enormi estensioni di terre emerse
sono state riservate a solo poche specie vegetali comprimendo o eliminando
del tutto migliaia di altre specie, e non solo vegetali, che in quelle aree
avevano sviluppato il loro appropriato habitat. È vero poi che l’agricoltura
moderna ha fortemente accelerato questo processo sacrificando in modo
esponenziale l’ambiente alla causa della produttività. D’altra parte,
l’aumento della popolazione mondiale ha fortemente sollecitato la ricerca
di strategie agronomiche che fossero in grado di sostenerla. Nel secolo
scorso i clamorosi aumenti delle rese produttive agricole sono stati conseguiti
grazie al crescente uso dei fertilizzanti e, successivamente, di altri
composti di origine chimica che fossero in grado di proteggere le piante
dagli attacchi di batteri, funghi, nematodi e insetti patogeni e di eliminare
quelle specie vegetali indesiderate.
La natura chimica stessa di questi composti, legata alla necessità che essi
sortiscano un drastico effetto su tutte quelle specie da controllare o eliminare,
li ha via via resi sempre più complessi, tossici e recalcitranti. Buona
parte di essi permane nell’ambiente con residui non-degradabili che di
conseguenza hanno un impatto negativo facilmente intuibile e che in molti
casi ha richiesto successivi interventi di decontaminazione. Ma anche
l’uso di pesticidi prontamente metabolizzabili può essere deleterio, poiché
essi presentano spesso un ampio spettro d’azione che li rende nocivi anche
nei confronti di specie viventi non dannose o addirittura nei confronti degli
antagonisti naturali dell’organismo bersaglio.
Da non sottovalutare, inoltre, che molte popolazioni di microrganismi,
insetti e piante possono acquisire resistenza verso certi composti nocivi,
specialmente in un’agricoltura intensiva nella quale l’eccessivo impiego
di formulati chimici impone all’ecosistema una enorme pressione
selettiva. Di conseguenza, lo sviluppo di resistenze e il successivo ritorno del patogeno hanno in passato indotto gli operatori agricoli ad aumentare
le dosi e/o la frequenza di applicazione e le industrie chimiche a ricercare
nuove generazioni di pesticidi.
Naturalmente, le conoscenze scientifiche odierne di chimica organica
consentono la creazione di nuove molecole adatte allo scopo, ma i costi
tendono ad aumentare per coprire gli investimenti nella ricerca e le regole
per la registrazione dei nuovi prodotti divengono sempre più rigorose.
Le industrie chimiche non sono dunque più disposte a investire cifre sempre
maggiori per mercati che sono destinati a restringersi
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