1,028 research outputs found
Intracellular pH measurements made simple by fluorescent protein probes and the phasor approach to fluorescence lifetime imaging
No full textA versatile pH-dependent fluorescent protein was applied to intracellular pH measurements by means of the phasor approach to fluorescence lifetime imaging. By this fit-less method we obtain intracellular pH maps under resting or altered physiological conditions by single-photon confocal or two-photon microscopy. RI Bizzarri, Ranieri/H-1779-201
Optimized biorecognition of cytochrome c 551 and azurin immobilized on thiol-terminated monolayers assembled on Au(111) substrates
No full textMolecular recognition between two redox partners, azurin and cytochrome c 551, is studied at the single-molecule level by means of atomic force spectroscopy, after optimizing azurin adsorption on gold via sulfhydryl-terminated alkanethiol spacers. Our experiments provide evidence of specific interaction between the two partners, thereby demonstrating that azurin preserves biorecognition capability when assembled on gold via these spacers. Additionally, the measured single-molecule kinetic reaction rate results are consistent with a likely transient nature of the complex. Interestingly, the immobilization strategy adopted here, which was previously demonstrated to favor electrical coupling between azurin (AZ) and the metal electrode, is also found to facilitate AZ interaction with the redox partner, if compared to the case of AZ directly adsorbed on bare gold. Our findings confirm the key role of a well-designed immobilization strategy, capable of optimizing both biorecognition capabilities and electrical coupling with the conductive substrate at the single- molecule level, as a starting point for advanced applications of redox proteins for ultrasensitive biosensing
Nuovi criteri di divisibilità
No full textNel presente lavoro viene fornita una trattazione didattica dei vari criteri di divisibilita
Food allergy in children: relationship between level of IgE intestinal cells and response to restricted diet
No full textIntact Microtubules Preserve Transient Receptor Potential Vanilloid 1 (TRPV1) Functionality through Receptor Binding
No full textThe transient receptor potential cation channel subfamily V member 1 (TRPV1) is a protein currently under scrutiny as a pharmacological target for pain management therapies. Recently, the role of TRPV1-microtubule interaction in transducing nociception stimuli to cells by cytoskeletal rearrangement was proposed. In this work, we investigate TRPV1-microtubule interaction in living cells under the resting or activated state of TRPV1, as well as in presence of structurally intact or depolymerized cytoskeletal microtubules. We combined a tool-box of high resolution/high sensitivity fluorescence imaging techniques (such as FRET, correlation spectroscopy, and fluorescence anisotropy) to monitor TRPV1 aggregation status, membrane mobility, and interaction with microtubules. We found that TRPV1 is a dimeric membrane protein characterized by two populations with different diffusion properties in basal condition. After stimulation with resiniferatoxin, TRPV1 dimers tetramerize. The tetramers and the slower population of TRPV1 dimers bind dynamically to intact microtubules but not to tubulin dimers. Upon microtubule disassembly, the interaction with TRPV1 is lost thereby inducing receptor self-aggregation with partial loss of functionality. Intact microtubules play an essential role in maintaining TRPV1 functionality toward activation stimuli. This previously undisclosed property mirrors the recently reported role of TRPV1 in modulating microtubule assembly/disassembly and suggests the participation of these two players in a feedback cycle linking nociception and cytoskeletal remodeling. RI Bizzarri, Ranieri/H-1779-201
Mini-open blind procedure versus limited open technique for carpal tunnel release: A 30-month follow-up study
No full textPurpose: To evaluate prospectively the safety and effectiveness of a mini-open blind technique for carpal tunnel release (group A) when compared with a limited open technique (group B). Methods: From November 1999 to May 2001 (mean follow-up period, 30 mo) we performed 222 carpal tunnel release procedures on 185 consecutive patients. All patients were affected by mild to moderate median nerve compression. Patients in group A (82 patients, 99 procedures) had a short transverse incision at the wrist (length, 2 cm). We used a manual surgical instrument that helps in blindly dividing the flexor retinaculum because it-has an integrated light source. The light makes it possible to locate precisely the tool blade by transillumination. Patients in group B (103 patients, 123 procedures) had a limited longitudinal incision (length, 3-4 cm), The preoperative and postoperative patient statuses were evaluated with an Italian modified version of the Boston Carpal Tunnel questionnaire with a mean of 30 months' follow-up after surgery (range, 24-39 mo). Results: Group A patients showed better results than group B patients in all of the sections of the Italian modified version of the Boston Carpal Tunnel questionnaire at a mean follow-up period of 19 months, whereas after a mean of 30 months of follow-up evaluation the differences between groups A and B tended to decrease. Disease recurred in 7 group B patients, whereas only 1 patient in group A experienced symptom recurrence at the latest office evaluation. Conclusions: The blind mini-invasive technique has been shown to be as safe as traditional techniques but the recovery period is significantly shortened. With the technique we described a low recurrence rate was observed. All patients in group A reported great reduction in preoperative pain and numbness
Inhibition of Amine Oxidases Activity by 1-acetyl-3,5-diphenyl-4,5-dihydro-(1H)-Pyrazole Derivatives
No full textA novel series of 1-acetyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole derivatives have been synthesised and investigated for the ability to inhibit selectively monoamine oxidases, swine kidney oxidase, and bovine serum amine oxidase. The newly synthesised compounds 1-6 proved to be reversible and non-competitive inhibitors of all types of the assayed amine oxidases. Compounds inhibit monoamine oxidases potently, displaying low 150 values of particular interest. In particular 1-acetyl-3-(2,4-dihydroxyphenyl)-5-(3-methylphenyl)-4,5-dihydro-(1H)-pyrazole 6 showed to be a potent monoamine oxidase inhibitor with a K-i of about 10(-8) M. Further insights in the theoretical evaluation of the possible interactions between the compounds and monoamine oxidase B have been developed through a computational approach. (C) 2002 Elsevier Science Ltd. All rights reserved
Fluorescence lifetime microscopy reveals the biologically-related photophysical heterogeneity of oxyblepharismin in light-adapted (blue) Blepharisma japonicum cells
No full textThe step-up photophobic response of the heterotrich ciliate Blepharisma japonicum is mediated by a hypericinic pigment, blepharismin, which is not present in any of the known six families of photoreceptors, namely rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins, and BLUF proteins. Upon irradiation, native cells become light-adapted (blue) by converting blepharismin into the photochemically stable oxyblepharismin (OxyBP). So far, OxyBP has been investigated mainly from a photophysical point of view in vitro, either alone or complexed with proteins. In this work, we exploit the vivid fluorescence of OxyBP to characterize its lifetime emission in blue B. Japonicum cells, on account of the recognized role of the fluorescence lifetime to provide physicochemical insights into the fluorophore environment at the nanoscale. In a biological context, OxyBP modifies its emission lifetime as compared to isotropic media. The phasor approach to fluorescence lifetime microscopy in confocal mode highlights that fluorescence originates from two excited states, whose relative balance changes throughout the cell body. Additionally, Cilia and kinetids, i.e., the organelles involved in photomovement, display lifetime asymmetry between the anterior and posterior part of the cell. From these data, some hypotheses on the phototransduction mechanism are proposed
Camera trapping the European wildcat (Felis silvestris silvestris) in Sicily (Southern Italy): preliminary results
No full textThe wildcat is an elusive species that is threatened with extinction in many parts of its range. In Sicily it still lives in a wide range of habitats. During 2006, camera traps were used to investigate the distribution of the wildcat over a 660 ha wide area on the south-western slope of Mount Etna (NE Sicily). Twelve out of 18 trapping stations provided a total of 24 photographs. Nine different individuals were identified using morphological criteria. Our work confirms the suitability of camera trapping for monitoring elusive carnivores
- …
