Isolation of organophosphorus-degrading bacteria from agricultural mediterranean soils

Il Microbiota delle piante, ovvero le piante hanno bisogno dei microrganismi

Le relazioni tra le piante e i fattori ambientali (il clima, i nutrienti, l’acqua, la composizione del suolo, etc) sono da tempo ampiamente studiate. Resta invece ancora molto da capire sul ruolo che la componente biologica del suolo (ci sono oltre cento milioni di cellule microbiche in un grammo di suolo!) ha sullo sviluppo e la salute delle piante. Nella rizosfera soprattutto (la porzione di suolo influenzata dalla presenza di radici), gli essudati radicali favoriscono lo sviluppo di microrganismi (batteri, funghi, protozoi, virus) che interagiscono con le radici e con il suolo nell’influenzare i processi di trasformazione ed assorbimento dei nutrienti, la crescita della pianta e le infez…

La Betulla dell’Etna: uno studio multidisciplinare sui fattori di deperimento della specie

La betulla dell’Etna (Betula aetnensis Rafin), è una delle specie arboree che durante le ultime glaciazioni si è spinta verso sud e dove oggi costituisce popolazioni pressoché relitte localizzate esclusivamente in Sicilia sulla sommità dell’Etna. I betulleti sono presenti sui versanti orientali ed occidentali dell’Etna, ad un’altitudine compresa tra 1.400 e 2.000 m s.l.m. Si tratta di popolamenti pionieri che colonizzano substrati vulcanici inalterati e/o poco evoluti dove costituiscono a volte dei piccoli boschi puri o misti a pino laricio. Questi boschi in passato erano sottoposti a ceduazioni, che dal 1987 non sono state più eseguite a seguito della istituzione del Parco Regionale dell’E…

Structure and composition of intertidal biofilms which enhance the settlement of the central-Mediterranean reef builder Dendropoma cristatum (Biondi 1859).

Introduction Marine biofilms are complex matrix of microorganisms and mucopolysaccharide substances which develop on all submerged surfaces, providing a variety of physical-bio-chemical cues which affect the settlement of a wide range of benthic organisms. Biofilm community composition, 3-D structure and metabolic activity vary over time. Few studies report the biological and physical changes in marine biofilm development in relationship to their effects on benthic colonisation. Biofilm maturity has been reported to enhance the settlement rate of the central-Mediterranean Dendropoma cristatum (Biondi, 1859), an intertidal vermetid gastropod which builds up ecologically relevant reefs, subje…

Restoration practices in Mediterranean habitats using native woody species

Since the beginning of the XXI century, Legambiente (a national environmental association), supported by the University of Palermo, has launched several naturalization projects within three Sicilian nature reserves: 1)Isola di Lampedusa (Agrigento Province); 2)Macalube di Aragona (Agrigento Province); 3)Lago Sfondato (Caltanissetta Province). Interventions were carried out on bare lands and degraded sites where natural vegetation cover was almost completely disappeared. The main aim was to restore native habitats following the principles of ecological restoration. Accordingly, differently from the classical approach, consisting in the use of preparatory species, usually Pines, native shrubs…

Settlement performance of the Mediterranean reef-builders Dendropoma cristatum (Biondi 1859) in response to natural bacterial films

The gastropod Dendropoma cristatum is a biogenic engineer of the central Mediterranean, forming reefs along the lower rocky intertidal fringe with a remarkable ecological role. To understand whether reef-associated biofilm cultivable bacterial and biofilm ageing may trigger the settlement of the juvenile snails, a combination of laboratory techniques and field experiments was used. Reef-associated biofilm cultivable bacteria were isolated, and a settlement-choice experiment was performed in situ on artificial biofilms composed of i) a mixture of six biofilm-forming selected isolates, ii) all the cultivable bacteria, and iii) 13-, 23-, 32-day old biofilms formed under naturalconditions. Overall,sett…

Hydrocarbonoclastic bacteria from a polluted harbour in Sicily (Italy): isolation, identification and characterization of their biotechnological potential.

Metabolic specialization is a general biological principle that shapes the assembly of microbial communities. Hydrocarbonoclastic bacteria (HCB) are marine bacteria that are specialised in hydrocarbon degradation and use hydrocarbons almost exclusively as unique C and energy source. HCB become dominant in oil-­‐impacted environments and are particularly adapted for removal of hydrocarbons from contaminated sites through bioremediation treatments. The petrochemical site of Priolo-­‐Augusta-­‐Melilli (Sicily, Italy), is a Site of National Interest (SIN) due to high levels of environmental contamination of the coastline and a specific "national program of environmental remediation and restorat…

Biopolymeric porous structure for selective oil sorption and activity intensification of oil-degrading bacteria

Oil pollution is one of the environmental concerns that are currently becoming a major issue in the petroleum industry. Among the different methods for environmental cleaning, the use of sorbents to recover the spilled oils is becoming more and more attractive because of their peculiar advantages such as reusability and recoverability of the oil. In this context, bioremediation is often considered a promising and cost-effective technology that could help a more sustainable recovery of contaminated water by using oil-degrading microorganisms. In this work, it is proposed a PCL-based biodegradable and floatable oil removal sponge, able to immobilize and increase biodegradation ability of hydr…

The occurrence of mycorrhizal fungi in Betula aetnensis Raf. roots: from ecological role to conservation strategies

Betula aetnensis Raf. is an endemic tree species of particular conservation value. It only thrives in the north-eastern slopes of Mount Etna (Sicily), from 1200 to 2100 m a.s.l. This pioneer plant is able to begin primary succession on nutrient-poor and water-limited soils (C = 0.17%; N = 0.05 ‰; P2O5 = 4.1 ppm), where beneficial mycorrhizal fungi (MF) may play a crucial role. In order to investigate MF role in B. aetnensis, plant roots from natural sites and nursery grown specimens were analyzed for both ectomycorrhizal and endomycorrhizal structures. Typical structures of both symbiosis were detected by root staining and morphological observations. Ectomycorrhizae (EM) were more abundant …

Biodegradation of oganophosphorus pesticides by soil bacteria

A number of studies in the 1980s and 1990s showed that crop-protection products, applied to drained fields, could move downwards through the soil profile and to the groundwater. Organophosphorus insecticides (OPs) are used all over the world for crop protection, for other agricultural practices such as sheep dipping and, in aquaculture, for the control of sea lice. Ops besides showing a specific neurotoxicity and have also been related to various modern diseases, including Creutzfeldt–Jakob (CJD) and the Gulf War syndrome. Although OPs are less persistent than Organoclorine pesticides (OCs), they still constitute an environmental risks thus increasing the social concern about their levels i…