196,116 research outputs found
The mechanism of the nitric oxide-mediated enhancement of tert-butylhydroperoxide-induced DNA single strand breakage.
No full text1 Caffeine (Cf) enhances the DNA cleavage induced by tert-butylhydroperoxide (tB-OOH) in U937 cells via a mechanism involving Ca2+-dependent mitochondrial formation of DNA-damaging species (Guidarelli el al., 1997b). Nitric oxide (NO) is not involved in this process since U937 cells do not express the constitutive nitric oxide synthase (cNOS).
2 Treatment with the NO donors S-nitroso-N-acetyl-penicillamine (SNAP, 10 mu M), or S-nitrosoglutathiane (GSNO, 300 mu M), however, potentiated the DNA strand scission induced by 200 mu M tB-OOH. The DNA lesions generated by tB-OOH alone, or combined with SNAP, were repaired with superimposable kinetics and were insensitive to anti-oxidants and peroxynitrite scavengers but suppressed by iron chelators.
3 SNAP or GSNO did not cause mitochondrial Ca2+ accumulation but their enhancing effects on the tB-OOH-induced DNA strand scission were prevented by ruthenium red, an inhibitor of the calcium uniporter of mitochondria. Furthermore, the enhancing effects of both SNAP and GSNO were identical to and not additive with those promoted by the Ca2+-mobilizing agents Cf or ATP.
4 The SNAP- or GSNO-mediated enhancement of the tB-OOH-induced DNA cleavage was abolished by the respiratory chain inhibitors rotenone and myxothiazol and was not apparent in respiration-deficient cells.
5 It is concluded that, in cells which do not express the enzyme cNOS, exogenous NO enhances the accumulation of DNA single strand breaks induced by tB-OOH via a mechanism involving inhibition of complex III
INPAR, CMT and RCMT aseismic moment solutions compared for the strongest damaging events (M≥4.8) occurred in the Italian region in the last decade
No full textPostharvest biocontrol of Monilinia laxa, Monilinia fructicola and Monilinia fructigena on stone fruit by two Aureobasidium pullulans strains
No full textThe antagonistic effects of yeasts,L1 and L8, isolated from carposphere of ‘Redhaven’ peachesweretested for the first time in the same experiment against three Monilinia species (M. laxa, M.fructicola and M.fructigena)in in-vitro and in-vivo trials. The two antagonists were selected after preliminary assaysfor their ability to reduce brown rot in peaches and nectarines, and both were identified by molecular and morphological tools as Aureobasidiumpullulans.Inin-vivo trials, neither the autoclaved cells, nor the sterile culturefiltrates of eitherantagonist showed any significant reduction of rot incidence produced by inoculaofthe three Monilinia species, while the washed cells of L1 and L8 completely inhibited M. laxa and M. fructicola rots and reducedM. fructigena infections by 70%and 90%, respectively. In other trials, nectarines treated with antagonist cells and inoculated with the pathogens were stored at 0°C for 21 days, plus 7 days at 20°C. The low temperature reduced brown rot development, since all fruit were free from disease symptomson removal from cold storage. However after 7 d at 20°C, untreated fruit were rotted over 45% depending on theMonilinia speciesbut theantagonists completely inhibited M. laxa and M. fructicola, while M. fructigena infections were reduced by89.8% and 91.2% by L1 and L8, respectively. For both strains,108cfu ml-1 was the most active concentration, althoughL1 showed good activity at a concentration of 107CFU ml-1.IsolateL8 at the concentration of 107 CFU ml-1was ineffective againstM. fructicola and M. fructigena, showing no difference between treated fruit and the control,excepting the case of nectarines inoculated with M. laxa, where L8 at the concentration of107cfu ml-1reducedthe brown rot infections with respect to the control. The increase in population density of A. pullulans strains L1 and L8 in the wounds of nectarines stored at 0° or 20°C was low but sufficient to control brown rot. In conclusion, the present preliminary study identified two antagonistic strains of A. pullulans as active ingredients forthe development of biofungicidesfor postharvest application against three Monilinia species that are responsible forhigh economic losses in stonefruit crops
Transcriptional profiling of apple fruit in response to heat treatment: involvement of a defense response during Penicillium expansum
No full textHeat treatment of harvested fruit has been demonstrated to be an effective and a safe approach for managing postharvest decay. In the present study, the effect of a hot water treatment (HT) (45. °C for 10. min) on the response of apple to blue mold infection was investigated. HT was applied to 'Ultima Gala' apples using 2 different methods. Wounded apples were: (1) inoculated with a Penicillium expansum spore suspension and then heat-treated after 1, 4 and 24. h (Inoc-HT); or (2) first heat-treated and then inoculated with a P. expansum spore suspension after 1, 4 and 24. h (HT-Inoc). All treated/inoculated apples were stored at 20. °C for 6 days. Significant reductions in fruit rot incidence, up to 100%, were observed using the Inoc-HT protocol at 4 and 24. h while a 30% reduction in blue mold incidence was found at 1 and 4. h using the HT-Inoc method. In vitro experiments showed no evident lethal effect of HT at 45. °C for 10. min on the germination of P. expansum conidia, indicating that this pathogen has a high heat tolerance. In order to investigate the molecular mechanisms involved in fruit response to heat treatment, an apple microarray was used to conduct a global transcriptional analysis of gene expression in apple at 0, 15, 30. min, 1, 4, 8 and 24. h after the heat treatment. The results provided evidence that at 1 and 4. h after heating, the HT apples had the highest number of differentially expressed genes. A significant upregulation of heat shock proteins, heat shock cognate protein, and heat shock transcription factor genes, involved in thermotolerance were observed. This indicates that the apple fruit respond to the heat treatment in a programmed manner and suggests that the genes responsible for thermotolerance may also be involved in the induced resistance response
Phenolic-rich juice prevents DNA single-strand breakage and cytotoxicity caused by tert-butylhydroperoxide in U937 cells: the role of iron chelation.
No full textThe antioxidant potential of phenolic compounds is generally linked to their ability to scavenge free radicals. However, in addition to their radical-scavenging activity, phenolic compounds can chelate metal ions, such as iron, to prevent their participation in Fenton-type reactions, which lead to the formation of free radicals. The aim of the present study was to evaluate the ability of a phenolic-rich juice made from grapes, cherries and berries to protect human myeloid leukemia (U937) cells from oxidative stress caused by tert-butylhydroperoxide (tB-OOH). Preincubation of cells with extracts of the phenolic-rich juice at different concentrations (0-200 mu M ferulic acid equivalents) for 3 h partially prevented cell death and abolished the DNA cleavage induced by tB-OOH. Moreover, when preincubating cells with the 100-mu M juice extract (the dose that diminished cell death by around 50%), the partial prevention of tB-OOH-induced formation of reactive oxygen species (ROS) and mitochondrial permeability transition pore opening was observed. The radical scavenger antioxidant N,N-diphenyl-1,4phenylene-diamine (DPPD) and the intracellular iron chelator o-phenanthroline (o-Phe) were also tested to know whether protective effects depended on radical-scavenging or iron-chelating activities. o-Phe prevented cell death, DNA cleavage and ROS generation, whereas DPPD only prevented cell death, suggesting that phenolics in the juice afforded protection against induced oxidative stress, most probably by means of an iron-chelating mechanism
Characterization of thiophanate methyl resistance in Italian Monilinia fructicola isolates
No full textMonilinia fructicola causes considerable damage to cultivated stone fruits in the temperate regions with an important economic impact. Monitoring the strains resistant to fungicides is essential to reduce economic losses associated with the peach and nectarine market. Although several works have focused on benzimidazole fungicide resistance worldwide in Monilinia spp., limited data report the benzimidazole resistance in European M. fructicola isolates. In order to assay the development of resistance to thiophanate methyl, the Alamar Blue test, a quick and reliable assay, was used and the results compared with those obtained with conventional amended medium. Our results show for the first time the presence in Italian M. fructicola isolates of a phenotype resistant to thiophanate methyl. In particular, 46 out of 63 isolates were found resistant, with EC50 values ranging from 0.99 μg ml-1 to 57.59 μg ml-1, values equal or higher than the inhibitory dose (1 μg ml-1). Point mutations in the β-tubulin gene were analyzed in 18 representative M. fructicola isolates, 15 with different levels of resistance (low and high resistance) and three sensitive. All resistant isolates tested showed a point mutation at codon 198 with respect to sensitive isolates isolates, i.e. GCA instead of GAA. In addition, all Italian isolates revealed a point mutation at codon 83 in the β-tubulin gene where the arginine was converted to glutamine with a punctual allelic change CAA instead of CGA
Peroxynitrite-mediated release of arachidonic acid from PC12 cells
No full textA short term exposure of PC12 cells to a concentration of tert-butylhydroperoxide (tB-OOH) causing peroxynitrite-dependent DNA damage and cytotoxiticity promoted a release of arachidonic acid (AA) that was sensitive to phospholipase A(2) (PLA(2)) inhibitors and insensitive to phospholipase C or diacylglycerol lipase inhibitors. The extent of AA release was also mitigated by nitric oxide synthase (NOS) inhibitors and peroxpnitrite scavengers. Low levels (10 mu M) of authentic peroxynitrite restored the release of AA mediated by tB-OOH in NOS-inhibited cells whereas concentrations of peroxynitrite of 20 mu M, or higher, effectively stimulated a PLA(2) inhibitor-sensitive release of AA also in the absence of additional treatments. These results are consistent with the possibility that endogenous as well as exogenous peroxynitrite promotes activation of PLA(2)
Il monastero di San Michele e l'architettura. Da Mauro Codussi alla costruzione della libreria
No full textShear-wave velocity models and complete earthquake source tensor in campanian volcanic areas (Vesuvio and Campi Flegrei).
No full textIsolated congenital absence of the nasal bones and its aesthetic surgical correction. Managing and case report
No full textA rare case of isolated congenital bone agenesis in a young woman referred to the authors for aesthetic correction of the dorsum profile is described. There are no descriptions of surgical treatment for this isolated facial defect in the literature. After a complete and accurate diagnostic study, a rhinoplasty was performed with a good result and without complications during a 2-year follow-up period. To explain this congenital malformation, several hypotheses were examined, such as bony resorption and embryologic bony development syndromes. This report describes the possibility of intervention in the case of nasal bone absence and shows how risks of structural instability can be avoided with an accurate preoperative study and a careful surgical approach
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