1,721,102 research outputs found
Il Microbiota delle piante, ovvero le piante hanno bisogno dei microrganismi
No full textLe 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 infezioni da parte di microrganismi patogeni. L’interazione suolo-pianta non è quindi diretta ma mediata dalla presenza di microrganismi che con la loro attività metabolica modulano lo sviluppo dei semi e la crescita della plantula, modificano la morfologia delle radici, interagiscono con la fisiologia e la biochimica della pianta e influenzano la disponibilità e l’assorbimento dei nutrienti
Making smart use of woody alien plants
No full textIt is unquestionable that some alien woody plant species are a major issue for biodiversity conservation. However, being alien species generally adapted to warmer conditions than autochthonous/local ones, they could be particularly suited to cope with the new environmental and climatic conditions that are also forecasted in the coming decades in Sicily. This poses an issue that is not easy to deal with, whether trying to use these species for the advantages they could bring, for instance in the new reforestation activities, while avoiding them becoming a serious problem for biodiversity conservation in natural and seminatural areas. Here, we present three study cases of non-native tree species which represent emblematic examples in that regard: Eucalyptus camaldulensis, Leucaena leucocephala and Acacia saligna. These tree species are very invasive in some ecological contexts, while being useful to meet ecological services in others. A sound planning activity could help distinguish where planting these species could be not only possible but also desirable, from areas where their presence should be totally avoided
Dalla Chimica alla Biochimica
No full textCome molecole semplici possono formare molecole complesse e come queste ultime possono addirittura dare origine ad esseri viventi come un batterio o addirittura un essere umano? Cosa rende i viventi profondamente diversi da un computer o da una semplice roccia? In questo capitolo assisterete ad una affascinante svolta nella storia evolutiva del nostro pianeta accaduta molti milioni di anni fa: la chimica del mondo non ancora vivente si evolve per tappe e fonda l’unità elementare chiamata cellula: la prima aggregazione di molecole chimiche che può essere definita “vivente”. Scoprirete come grazie alla termodinamica, che vige in una cellula come altrove, può avvenire un insieme vastissimo di processi chimici costituenti il metabolismo cellulare ed anche come la cellula crea ed immagazzina energia in speciali molecole, come l’ATP. Conoscerete delle molecole molto speciali, gli enzimi, che, catalizzando reazioni chimiche complesse, permettono che queste avvengano in un tempo così ridotto da permettere e gestire la vita
Microbes and Persistent Organic Pollutants in the Marine Environment
Full text linkMarine pollution has increased reaching the entire marine environment, from the surface to the deepest sediment, and has become more concerning in the last 70 years. Persistent organic pollutants (POPs) are a fraction of ocean waste that includes, among the others, polycyclic aromatic hydrocarbons (PAHs) and plastic polymers. These chemicals have an extremely long half-life, and (bio)accumulate and damage the marine flora and fauna, and, ultimately, human health. Some organisms have evolved enzymes to attack POPs in the environment and transform them into biomass and CO2. Several microorganisms degrade many POPs in relatively short time. A wide variety of bacteria has been isolated with different techniques, and key catabolic enzymes used to degrade the most persistent oil hydrocarbon fractions have been identified. For plastic waste, there is less evidence of microbial degradation, but a few recent studies are revealing that a biodegradation potential exists for some of the most recalcitrant plastic polymers as well. The scientific community is focusing on microorganisms and their enzymes for POP uptake and removal from the environment, while searching novel biopolymers (also from microbiological origin) to substitute oil-derived plastics
Innovative, ecofriendly biosorbent-biodegrading biofilms for bioremediation of oil- contaminated water
Full text linkImmobilization of microorganisms capable of degrading specific contaminants significantly promotes bioremediation processes. In this study, innovative and ecofriendly biosorbent-biodegrading biofilms have been developed in order to remediate oil-contaminated water. This was achieved by immobilizing hydrocarbon-degrading gammaproteobacteria and actinobacteria on biodegradable oil-adsorbing carriers, based on polylactic acid and polycaprolactone electrospun membranes. High capacities for adhesion and proliferation of bacterial cells were observed by scanning electron microscopy. The bioremediation efficiency of the systems, tested on crude oil and quantified by gas chromatography, showed that immobilization increased hydrocarbon biodegradation by up to 23 % compared with free living bacteria. The resulting biosorbent biodegrading biofilms simultaneously adsorbed 100 % of spilled oil and biodegraded more than 66 % over 10 days, with limited environmental dispersion of cells. Biofilm-mediated bioremediation, using eco-friendly supports, is a low-cost, low-impact, versatile tool for bioremediation of aquatic systems
The ancient urban agroforestry systems of the Conca D'Oro (Palermo, Italy) need protection to defend the city
No full textThe favorable environmental conditions together with the ancient agronomic practices, e.g.
the irrigation systems introduced by the Arabs, have made the plain surrounding Palermo,
known as Conca d’Oro, the unique agriculture landscape famous worldwide. Several tree and
vegetable species have spread throughout in time but the new crops, instead of replacing the
others, were often integrated exploiting the different heights of the tree canopies. The result
was the creation of complex agroecosystems characterized by orchards with several layers
of trees (as walnut, loquat, citrus) and empty spaces where the farmers cultivated vegetables.
The grass fed the animals in the stables while manure was returned to the fields. Now the traditional
system has changed (simplification, disappearance of animals, abandonment) but new
functions, in the meantime, are attributed to these areas: air purification, high quality products,
biodiversity conservation, preservation of history, and, recently, training of young farmers.
The purpose of this communication is to describe the agroforestry features of today’s Conca
D’Oro system and that of the recent past and to illustrate its new functions while the city is
engulfing its last agricultural areas. It is evident that, without the support and control of the
public administration, the green spots left in the Conca D’Oro (one is indicated by the yellow
arrow) will disappear and one of the most beautiful landscapes in the world will be lost forever
A modified culture medium for improved isolation of marine vibrios
Full text linkMarine Vibrio members are of great interest for both ecological and biotechnological research, which often relies on their isolation. Whereas many efforts have been made for the detection of food-borne pathogenic species, much less is known about the performances of standard culture media toward environmental vibrios. We show that the isolation/enumeration of marine vibrios using thiosulfate-citrate-bile salts-sucrose agar (TCBS) as selective medium may be hampered by the variable adaptability of different taxa to the medium, which may result even in isolation failure and/or in substantial total count underestimation. We propose a modified TCBS as isolation medium, adjusted for marine vibrios requirements, which greatly improved their recovery in dilution plate counts, compared with the standard medium. The modified medium offers substantial advantages over TCBS, providing more accurate and likely estimations of the actual presence of vibrios. Modified TCBS allowed the recovery of otherwise undetected vibrios, some of which producing biotechnologically valuable enzymes, thus expanding the isolation power toward potentially new enzyme-producers Vibrio taxa. Moreover, we report a newly designed Vibrio-specific PCR primers pair, targeting a unique rpoD sequence, useful for rapid confirmation of isolates as Vibrio members and subsequent genetic analyses
Gordonia sp. SoCg alkB gene confers the ability to degrade and use n-alkanes as carbon source in Gram positive bacteria
No full textGordonia sp. SoCg, a Gram positive strain able to grow on long chain n-alkanes1, possess a single copy of
alkB2 gene, whose product is required for n-alkane hydroxylation3. An analysis of alkB flanking regions
revealed five ORFs which were designed as orf1, rubA3, rubA4, rubB and alkU, according to the sequence
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homology with that of known alk clusters3. In G. sp. SoCg the transcription of these genes was induced by
long-chain and solid n-alkanes as revealed by quantitative RT-PCR, and the essential role of alkB in nalkane
degradation was demonstrated by the construction of an alkB disruption mutant strain3. The SoCg
alkB gene was successfully expressed in Streptomyces coelicolor M145 (M145-AH), and the production of
1-hexadecanol from n-hexadecane oxidation was observed3.
A differential study of global gene expression of M145-AH cultures was performed, where n-hexadecane
(C16) glucose (GLU) and none (NC) were provided as only carbon source, respectively. Proteomic analysis,
based on 2D-DIGE and MS procedures, revealed a gradual metabolic adaptation to n-hexadecane
utilization, not dissimilar from that one revealed in specialized alkane-degraders4. In addition, expression
profiles of central carbon metabolism enzymes revealed that the addition of a single gene confers the ability
to use recalcitrant pollutants as simple sugars in Streptomyces.
Altogether these data, expanding the knowledge on n-alkane bioconversion mechanisms in Gram positive
bacteria, could provide new technological platforms for bioremediation studies and strategies.
Quatrini, P., Scaglione, G., De Pasquale, C., Riela, S., & Puglia, A. M. (2008). Isolation of gram-positive n-alkane degraders from a
hydrocarbon- contaminated mediterranean shoreline. Journal of Applied Microbiology, 104(1), 251-259.
Lo Piccolo, L., De Pasquale, C., Fodale, R., Puglia, A. M. & Quatrini, P. . An alkane hydroxylase system of Gordonia sp. Strain SoCg is
involved in degradation of solid n-alkanes. Applied and Environmental Microbiology. In revision.
van Beilen, J. B., & Funhoff, E. G. (2007). Alkane hydroxylases involved in microbial alkane degradation. Applied Microbiology and
Biotechnology, 74(1), 13-21.
Sabirova, J. S., Ferrer, M., Regenhardt, D., Timmis, K. N., & Golyshin, P. N. (2006). Proteomic insights into metabolic adaptations in
Alcanivorax borkumensis induced by alkane utilization. Journal of Bacteriology, 188(11), 3763-3773
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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