Search results for "biologia generale"
showing 10 items of 319 documents
Molecular epidemiology of KPC-producing Klebsiella pneumoniae from invasive infections in Italy: Increasing diversity with predominance of the ST512 …
2016
Objectives The spread of carbapenem-resistant Enterobacteriaceae (CRE) represents one of the most worrisome problems for clinical medicine worldwide. In Italy, the Antibiotic-Resistance-Istituto Superiore di Sanita surveillance network, in collaboration with the Committee for Antimicrobial Agents of the Italian Society of Clinical Microbiologists, promoted a study to investigate the carbapenem-resistance mechanisms, clonal relatedness and capsular typing of a recent collection of carbapenem-resistant Klebsiella pneumoniae (CR-KP). Methods A total of 17 laboratories distributed across Italy collected all consecutive non-replicate CR-KP isolated from invasive infections during two different s…
Rhodococcus aetherivorans BCP1 as cell factory for the production of intracellular tellurium nanorods under aerobic conditions
2016
Tellurite (TeO3 2−) is recognized as a toxic oxyanion to living organisms. However, mainly anaerobic or facultative-anaerobic microorganisms are able to tolerate and convert TeO3 2− into the less toxic and available form of elemental Tellurium (Te0), producing Te-deposits or Te-nanostructures. The use of TeO3 2−-reducing bacteria can lead to the decontamination of polluted environments and the development of “green-synthesis” methods for the production of nanomaterials. In this study, the tolerance and the consumption of TeO3 2− have been investigated, along with the production and characterization of Te-nanorods by Rhodococcus aetherivorans BCP1 grown under aerobic conditions. Aerobically …
Plasma modified PLA electrospun membranes for actinorhodin production intensification in Streptomyces coelicolor immobilized-cell cultivations
2017
Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomycete submerged cultivations, thus, resulting in an improved biosynthetic capability. In this work, electrospun polylactic acid (PLA) membranes, subjected or not to O2-plasma treatment (PLA-plasma), were used as support for immobilized-cell submerged cultivations of Streptomyces coelicolor M145. This strain produces different bioactive compounds, including the blue-pigmented actinorhodin (ACT) and red-p…
Anticancer activity of biogenerated silver nanoparticles: an integrated proteomic investigation
2018
Silver nanoparticles (AgNPs), embedded into a specific polysaccharide (EPS), were biogenerated by Klebsiella oxytoca DSM 29614 under aerobic (AgNPs-EPSaer) and anaerobic conditions (AgNPs-EPSanaer). Both AgNPs-EPS matrices were tested by MTT assay for cytotoxic activity against human breast (SKBR3 and 8701-BC) and colon (HT-29, HCT 116 and Caco-2) cancer cell lines, revealing AgNPs-EPSaer as the most active, in terms of IC50, with a more pronounced efficacy against breast cancer cell lines. Therefore, colony forming capability, morphological changes, generation of reactive oxygen species (ROS), induction of apoptosis and autophagy, inhibition of migratory and invasive capabilities and prote…
A combined physical-chemical and microbiological approach to unveil the fabrication, provenance, and state of conservation of the Kinkarakawa-gami ar…
2020
AbstractKinkarakawa-gami wallpapers are unique works of art produced in Japan between 1870 and 1905 and exported in European countries, although only few examples are nowadays present in Europe. So far, neither the wallpapers nor the composing materials have been characterised, limiting the effective conservation–restoration of these artefacts accounting also for the potential deteriogen effects of microorganisms populating them. In the present study, four Kinkarakawa-gami wallpapers were analysed combining physical–chemical and microbiological approaches to obtain information regarding the artefacts’ manufacture, composition, dating, and their microbial community. The validity of these met…
The SCO1731 methyltransferase modulates actinorhodin production and morphological differentiation of Streptomyces coelicolor A3(2)
2018
AbstractStreptomyces coelicolor is a Gram-positive microorganism often used as a model of physiological and morphological differentiation in streptomycetes, prolific producers of secondary metabolites with important biological activities. In the present study, we analysed Streptomyces coelicolor growth and differentiation in the presence of the hypo-methylating agent 5′-aza-2′-deoxycytidine (5-aza-dC) in order to investigate whether cytosine methylation has a role in differentiation. We found that cytosine demethylation caused a delay in spore germination, aerial mycelium development, sporulation, as well as a massive impairment of actinorhodin production. Thus, we searched for putative DNA…
The seed endosphere of Anadenanthera colubrina is inhabited by a complex microbiota, including Methylobacterium spp. and Staphylococcus spp. with pot…
2018
Background and aims: Plant seeds are emerging micro–habitats, whose importance as reservoir and vector of beneficial microbes just begins to be recognized. Here we aimed to characterize the bacterial microbiota of the Anadenanthera colubrina seed endosphere, with special focus to beneficial traits and to the colonization pattern. Methods: Cultivation–dependent (isolation from surface–sterilized seeds) and cultivation–independent (pyrosequencing of 16S rRNA gene from metagenomic seed DNA) analyses, functional tests and microscopical investigations (fluorescence in situ hybridization coupled with confocal laser scanning microscopy (FISH-CLSM) were performed. Results: We isolated several Methy…
Antimicrobial and Antibiofilm Activity of a Recombinant Fragment of β-Thymosin of Sea Urchin Paracentrotus lividus
2018
With the aim to obtain new antimicrobials against important pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa, we focused on antimicrobial peptides (AMPs) from Echinoderms. An example of such peptides is Paracentrin 1 (SP1), a chemically synthesised peptide fragment of a sea urchin thymosin. In the present paper, we report on the biological activity of a Paracentrin 1 derivative obtained by recombination. The recombinant paracentrin RP1, in comparison to the synthetic SP1, is 22 amino acids longer and it was considerably more active against the planktonic forms of S. aureus ATCC 25923 and P. aeruginosa ATCC 15442 at concentrations of 50 µ
Polysaccharide-based silver nanoparticles synthesized by Klebsiella oxytoca DSM 29614 cause DNA fragmentation in E-coli cells
2016
Silver nanoparticles (AgNPs), embedded into a specific exopolysaccharide (EPS), were produced by Klebsiella oxytoca DSM 29614 by adding AgNO3 to the cultures during exponential growth phase. In particular, under aerobic or anaerobic conditions, two types of silver nanoparticles, named AgNPs-EPS(aer) and the AgNPs-EPS(anaer), were produced respectively. The effects on bacterial cells was demonstrated by using Escherichia coli K12 and Kocuria rhizophila ATCC 9341 (ex Micrococcus luteus) as Gram-negative and Gram-positive tester strains, respectively. The best antimicrobial activity was observed for AgNPs-EPS(aer), in terms of minimum inhibitory concentrations and minimum bactericidal concentr…
Daclatasvir-based regimens in HCV cirrhosis: experience from the Italian early access program
2019
AbstractWe reported the efficacy and safety data for daclatasvir (DCV)-based all-oral antiviral therapy in patients treated in the Italian compassionate-use program. 275 patients were included (202 male-73.5%, mean age: 57.4 years, 62 HIV-coinfected, 94 with recurrence of hepatitis C post-OLT). Forty-nine patients (17.8%) had Child-Pugh B, Genotype(G) distribution was: G1a:72 patients (26.2%), G1b:137 (49.8%); G3:40 (14.5%) and G4:26 (9.5%). Patients received DCV with sofosbuvir(SOF) (n = 221, 129 with ribavirin(RBV) or with simeprevir (SMV) or asunaprevir (ASU) (n = 54, 19 with RBV) for up to 24 weeks. Logistic regression was used to identify baseline characteristics associated with sustai…