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101.
Cunsolo V Foti S La Rosa C Saletti R Canters GW Verbeet MP 《Journal of mass spectrometry : JMS》2003,38(5):502-509
An electrospray ionisation (ESI) mass spectrometric method for the determination of the equilibrium constant and free energy (DeltaG) of protein unfolding was used to monitor the denaturation process at different pH of three metallo-proteins, i.e. wild-type copper azurin, zinc azurin and wild-type amicyanin. The time course of the unfolding process was followed by dissolving the proteins under denaturing conditions (methanol-water (1 : 1, v/v)) at different pH (2.5, 3.0, 3.5) and recording ESI spectra at time intervals. The spectra showed two series of peaks, corresponding to the native holo-protein and the unfolded apo-protein. From the intensity ratio of these two series of peaks at increasing time and at equilibrium, the equilibrium constants for the unfolding process for the three proteins could be determined. From these equilibrium constants a DeltaG degrees derivation was attempted. The DeltaG degrees values obtained decrease with decrease in pH, in agreement with the expected reduction of conformational stability of proteins at lower pH. The results obtained confirm that ESI-MS can be used for monitoring of unfolding process and to derive quantitative thermodynamic data. 相似文献
102.
Bazzicalupi C Bencini A Bianchi A Duce C Fornasari P Giorgi C Paoletti P Pardini R Rosaria Tinè M Valtancoli B 《Dalton transactions (Cambridge, England : 2003)》2004,(3):463-469
The coordination properties of the ditopic oxa-aza macrocycles L1-L3 toward Ni(II) and Co(II) have been investigated by means of potentiometric and UV-vis spectrophotometric measurements. L1-L3 contain two triamine and/or tetraamine chains separated by two dioxa chains and form both mono- and dinuclear complexes in aqueous solution. In the [ML]2+ complexes, the metal ion is coordinated by one of the two polyamine moieties, while the other does not participate in the coordination. In the dinuclear complexes each metal ion is coordinated, almost independently, to a single polyamine moiety. Under aerobic conditions the binuclear Co(II) complexes of the ligands L1-L3 are able to bind molecular oxygen, with a bridging coordination of O2 between the two metals. 相似文献
103.
Rosaria Ciajolo Mohamud A. Jama Angela Tuzi Aldo Vitagliano 《Journal of organometallic chemistry》1985,295(2):233-238
The complex η5-[Pd(CH2CHCMeCH2CH2CHCMe2)-(MeCN)](BF4), a model for a key intermediate in diene polymerization, crystallizes in the monoclinic space group P21/c, a 11.362(2), b 13.655(4), c 10.046(2) Å, β 134.80(1)°. The structure was solved by conventional Patterson and Fourier syntheses and refined by full matrix least squares techniques to a final discrepancy index R = 0.058 for 1710 independent reflections. The palladium and nitrogen atoms, the center of gravity of the allyl triangle, and the middle point of the coordinated double bond are coplanar. The side chain of the organic moiety is located in the syn position with respect to the η3-allyl group. The orientation of the coordinated double bond, which forms an angle of 26° with the coordination plane, is novel for palladium(II) complexes. 相似文献
104.
Valentina Pagliara Marina De Rosa Paola Di Donato Rosarita Nasso Antonio DErrico Francesca Cammarota Annarita Poli Mariorosario Masullo Rosaria Arcone 《Molecules (Basel, Switzerland)》2021,26(23)
Among matrix metalloproteinases (MMPs), MMP-9/2 are key enzymes involved in the proteolysis of extracellular matrices in the inflammatory process and in cancer. Since MMP-9/2 expression levels, activity, and secretion is up-regulated during inflammation in response to pro-inflammatory cytokines, such as interleukin-6 (IL-6), many efforts have been devoted to identifying factors that could inhibit the IL-6-induced MMP-9/2 expression. Up to now, several reports indicated that polyphenols from fruits and vegetables are among the major components of health promotion for their antioxidant properties and also for their anti-inflammatory and anti-cancer agents. Among plant derived polyphenols, lemon (Citrus limon) peel extract (LPE) shows anti-cancer properties in various cancer types. In our previous work, we demonstrated that LPE can reduce IL-6-induced migration/invasiveness and MMP-9/2 up-regulation in some gastric cancer cell lines. This study aims to exploit the anti-cancer properties of LPE using an in vitro system model of inflammation, consisting of IL-6-exposed human primary colon cancer cells. We first analyzed the effect of LPE on IL-6-induced cell migration and invasiveness by wound healing and Boyden chamber assay, respectively. The MMP-2 mRNA expression levels and gelatinolytic activity in the cell culture media were determined by q-PCR analysis and gelatin zymography, respectively, and finally, the effects of LPE on IL-6-induced JAK2/STAT3 signaling pathways have been investigated by Western blotting analysis. Our results show that LPE is able to inhibit the IL-6-dependent cell migration and invasiveness associated with the up-regulation of MMP-2 expression levels and that these effects are correlated to the STAT3 phosphorylation in human primary T88 and T93 colon cancer cells. 相似文献
105.
Rosaria Volpini Emidio Camaioni Stefano Costanzi Sauro Vittori Gloria Cristalli 《Helvetica chimica acta》1998,81(12):2326-2331
Coupling of 4,6-dichloro-1H-imidazo[4,5-c]pyridine (2,6-dichloro-3-deaza-9H-purine) ( 1 ) with 1,2-O-di-acetyl-5-O-benzoyl-3-deoxy-β-D -ribofuranose ( 2 ), employing the acid-catalyzed fusion method, is reported (Scheme 1). The condensation reaction was regioselective and gave the three N1-glycosylation products 3 – 5 , whereas no N3-nucleosides were detected. Treatment of 3 – 5 with methanolic ammonia afforded the corresponding deprotected nucleosides 6 – 8 . Compounds 6 and 7 were assigned the structure of the β-D - and α-D -anomeric N1-(3′-deoxyribo)nucleosides, respectively. The third derivative 8 proved to be the α-D -anomer of a 3′-deoxyarabinonucleoside deriving from epimerization at C(2) of the sugar. The 2-chloro- and N6-substituted derivatives 9 , 11 , and 13 of 3′-deoxy-3-deazaadenosine ( 10 ) and of its α-D -anomer 12 can be obtained from these versatile synthons (Schemes 2 and 3). 相似文献
106.
Simone Cristoni Laura Molin Antonella Lai Luigi Rossi Bernardi Salvatore Pucciarelli Marco Agostini Chiara Bedin Donato Nitti Roberta Seraglia Ombretta Repetto Vincenza Flora Dibari Rosaria Orlandi Pablo Martínez‐Lozano Sinues Pietro Traldi 《Rapid communications in mass spectrometry : RCM》2009,23(17):2839-2845
107.
Rosaria Silipo Gustavo Deco Bernd Schürmann Rossano Vergassola Celio Gremigni 《Chaos, solitons, and fractals》2001,12(14-15):2877-2888
Several approaches have been recently introduced to characterize and classify signals based on the underlying hidden dynamic. Markov models represent a natural choice for describing the dynamic evolution of a signal. However, the right selection of the memory of the process is essential for the correctness of the Markov model and a mathematically well-founded criterion is necessary to establish when the Markov model is a good approximation of the process. We review an information-theoretic based method that introduces the concept of information flow as such a criterion. The information flow describes the progressive loss of statistical dependence between the entire past and a point ahead in the future, which is indirectly related with the hidden dynamic of the signal. An approximated measure of information flow can be used as the discriminating statistic for selecting the optimal Markov model in terms of the shortest memory required. This technique is applied to investigate the underlying Markovian dynamics of the heart rate variability (HRV) for subjects in different patho-physiological conditions. Markov models with different memories seem to be associated with the circadian cycle and with different pathologies. Furthermore, the precursor character of the information flow for predicting ventricular tachycardia (VT) is discussed. 相似文献
108.
In the framework of the numerical solution of linear systems arising from image restoration, in this paper we present an adaptive approach based on the reordering of the image approximations obtained with the Arnoldi-Tikhonov method. The reordering results in a modified regularization operator, so that the corresponding regularization can be interpreted as problem dependent. Numerical experiments are presented. 相似文献
109.
Vincenzo Cunsolo Vera Muccilli Rosaria Saletti Salvatore Foti 《Journal of mass spectrometry : JMS》2013,48(2):148-153
Donkey's milk (DM), representing a safe and alternative food in both IgE‐mediated and non‐IgE‐mediated cow's milk protein allergy, can be categorized as precious pharma‐food. Moreover, an economically relevant interest for the use of DM in cosmetology is also developing. The detection of adulterations and contaminations of DM is a matter of fundamental importance from both an economic and allergenic standpoint, and, to this aim, fast and efficient analytical approaches to assess the authenticity of this precious nutrient are desirable. Here, a rapid matrix‐assisted laser desorption/ionization‐time‐of‐flight mass spectrometry (MALDI‐TOF MS)‐based method aimed to the detection of bovine or caprine milk in raw DM is reported. The presence of the extraneous milks was revealed by monitoring the protein profiles of the most abundant whey proteins, α‐lactalbumin (α‐LA) and β‐lactoglobulin, used as molecular markers. The possibility of obtaining a quantitative analysis of the level of cow or goat milk in DM based on the MALDI‐TOF peak areas of α‐LAs was also explored. The results showed that the experimental quantitative values were in good agreement with the real composition of each mixture. As pretreatment of the milk samples is not required, and owing to the speed and the high sensitivity of MALDI‐MS, the protocol here reported could represent a reliable method for routine analyses aimed to assess the absence of contamination in raw fresh DM samples. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
110.
Emanuela Esposito Irene Paterniti Emanuela Mazzon Tiziana Genovese Maria Galuppo Rosaria Meli Placido Bramanti Salvatore Cuzzocrea 《BMC neuroscience》2011,12(1):31