130,974 research outputs found
Ecological principles and methodologies for revealing microbial diversity and functions in complex microbial communities
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Metodo per la profilassi e il controllo delle infezioni patogene delle api, e relativa composizione
No full textLa presente invenzione ha per oggetto un’associazione probiotica per la
protezione della salute delle api, in particolare per la protezione nei confronti
di patologie batteriche, come ad esempio quella causata da Paenibacillus
larvae, agente patogeno della Peste American
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
Mangrovivirga cuniculi Sefrji & Michoud & Marasco & Merlino & Daffonchio 2021, SP. NOV.
No full textDESCRIPTION OF MANGROVIVIRGA CUNICULI SP. NOV. Mangrovivirga cuniculi (cu.ni.cu′ li. L. gen. n. cuniculi of a burrow, named because the type species was isolated from a crab burrow). The cell morphology and chemotaxonomic characteristics are given in the genus description. Cells are 0.3–0.5 µm wide and 1–1.2µm long. Its colonies are circular with a diameter of 1–2mm and feature regular edges, a smooth and shiny surface, and an orange colour caused by the production of orange carotenoids. The permissive conditions for growth are a temperature of 20–40 °C (optimum, 37°C), pH 6–10 (optimum, pH 8) and 3%–11% NaCl for salinity (optimum, 7%–9% NaCl). The carbon sources used for growth are pectin, 2-deoxy-D-ribose,Dribose, 5-keto-D-gluconic acid,L-ornithine, dihydroxyacetone, thymidine, uridine and adenosine. The genome harbours genes responsible for protection against oxidative, osmotic and salinity stresses, and includes genes encoding proteins that produce osmoprotectants and carotenoids. The cells are negative for amylase, protease, lipase, cellulase, indole, siderophore production and phosphate solubilization, and are positive for auxin (IAA) and ammonia production. The strain is unable to reduce nitrate to nitrite. The type strain, R1DC9 T (=KCTC 72349 T =JCM 33609 T =NCCB 100698 T), was isolated from bioturbated mangrove sediment at the Ibn Sina Field Research Station and Nature Conservation Area in KAUST, Saudi Arabia. The genomic DNA G+C content and genome size of the type strain are 63.1 mol% and 4661901 bp, respectively.Published as part of Sefrji, Fatmah O., Michoud, Grégoire, Marasco, Ramona, Merlino, Giuseppe & Daffonchio, Daniele, 2021, MaNgROVIVIRga CUNICULI gen. nov., sp. nov., a moderately halophilic bacterium isolated from bioturbated Red Sea mangrove sediment, and proposal of the novel family MaNgROVIVIRgaCeae fam. nov., pp. 1-11 in International Journal of Systematic and Evolutionary Microbiology (004866) (004866) 71 (7) on page 9, DOI: 10.1099/ijsem.0.004866, http://zenodo.org/record/622410
Effeti delle piante transgeniche sui microrganismi della rizosfera: biodiversità e scambio genico orizzontale.
No full textHalo-alkalitolerant and thermostable cellulases with improved tolerance to ionic liquids and organic solvents from Paenibacillus tarimensis isolated from the Chott El Fejej, Sahara desert, Tunisia
No full textThe wide number of industrial processes applying cellulases highlights the importance of discovering robust enzymes able to work under harsh conditions. In this study, carboxymethyl cellulase (CMCase) activity of Paenibacillus tarimensis was characterized. A high activity was observed in pH range 3.0–10.5 and 9 mM–5 M NaCl. In high salt buffer at 80 °C, >80% and >76% of relative activity was retained at 20% of the ionic liquids (ILs) [EMIM]Ac and [BMIM]Cl; while >40% was detected with 40% [BMIM]Cl. Five CMCases were detected by renaturing SDS–PAGE. Their activity was retained in presence of 1.7 up to 5 M NaCl (for CMC1) or 4.6 M KCl; 5% organic solvents or 10 mM bivalent ions, EDTA and heavy metals; under neutral and halo-alkaline conditions. These cellulases stabile and highly functional under harsh conditions are promising candidates for application in detergents, textiles, paper/pulp industry; and simultaneous ILs treatment-saccharification of lignocellulose
Anaerobic digestion of olive mill effluents : microbiological and processing aspects
No full textOlive mill effluents have been treated by anaerobic digestion, using a laboratory scale, fixed bed, upflow digester. The process was conducted with two different retention times (2 and 1 days); organic load was increased up to 40 kg COD/m(3)d. COD removal and biogas production were used as indicator of process efficiency. Counts of the main microbial groups involved in methanogenesis were determined to study microorganisms behaviour with different process conditions.
The best COD removal (70-80%) was obtained with 2 days retention time and organic load of 5.5-9.5 kg COD/m(3)d By working with an organic load of 40 kg COD/m(3)d at 1 day retention time, plant performances decreased but the process was not inhibited
Screening of plant growth promoting traits of Bacillus thuringiensis
No full textThis study aimed to evaluate the plant growth promoting (PGP) potential of Bacillus thuringiensis. In this context, several genetic determinants of factors implicated in PGP potential were investigated by polymerase chain reaction (PCR) in 16 B. thuringiensis strains of different origin and belonging to different subspecies. PCR screening was performed on acid phosphatase, phytase, siderophore biosynthesis protein, 1-aminocyclopropane-1-carboxylate (ACC) deaminase and indolpyruvate decarboxylase (ipdC). Production of indol acetic acid (IAA)-like compounds and of ACC deaminase, and capability of solubilising mineral phosphate were investigated by phenotypic tests. All the strains were PCR positive for the presence of the siderophore biosynthesis protein, ACC deaminase and acid phosphatase genes. Five and seven strains gave an amplicon with the expected length for the phytase and ipdC genes respectively. All the strains produced IAA compounds and seven had a high capacity to solubilise inorganic phosphorous. Qualitative phenotypic test for ACC deaminase activity showed that seven strains are able to grow on salt minimal medium containing ACC as sole nitrogen source, indicating the expression of the accd genes. Our screening results in thirteen strains having more than one PGP trait and showed that B. thuringiensis harbours and expresses several PGP determinants that could be very interesting in field application to enhance the plant growth. To our knowledge, this is the first report on the multiple plant growth promoting potential of B. thuringiensis
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