171,500 research outputs found
MODULATION OF THE ENZYMATIC ACTIVITY AND MEMBRANE BINDING PROPERTIES OF SOYBEAN LIPOXYGENASE-1 THROUGH LIMITED PROTEOLYSIS AND METAL SUBSTITUTION
No full textLipoxygenases are non-heme, non-sulfur iron containing enzymes that catalyze the dioxygenation of polyunsatured fatty acids containing one or more pentadiene systems to the corresponding hydroperoxy derivatives. Structural studies in solution of the mammalian and plant enzyme revealed that the latter has a more stable and compact conformation1. As yet, metal atom extraction, reconstitution and substitution with vicariate metals have not been successfully applied to soybean lipoxygenase-1, because of the highly buried position of the iron atom within the active site. Tryptic digestion of lipoxygenase-1 and the subsequent isolation of the 60 kDa C-terminal region allowed to generate a “mini-lipoxygenase-1 (miniLOX)” that retains the catalytically active iron, but in a more accessible position2. In this study, we investigated by near-UV-circular dichroism and fluorescence spectroscopies the structural and functional effects of iron removal, reconstitution and vicariation in miniLOX. Moreover, we report the kinetic analysis and the membrane binding ability of the apo- and metal-substituted forms of miniLOX, using fluorescence resonance energy transfer and monolamellar vesicles. Taken together, these data demonstrate an unprecedented structural role of iron, which is involved not only in the catalytic activity but also in the membrane binding ability of lipoxygenase-1.1. Dainese E. Sabatucci A. van Zadelhoff G. Angelucci C. B. Vachette P., Veldink G. Finazzi Agrò A. and Maccarrone M. (2005). J. Mol. Biol. 349, 143-152.2. Maccarrone M. Salucci M. L. van Zadelhoff G. Malatesta F. Veldink, G. Vliegenthart J. F. and Finazzi Agrò A. (2001). Biochemistry 40, 6819-6827.[...
The account of a lifetime
No full textThe book is a scientific tribute to Adriano Gozzini (1917-1994) on the occasion of the 20th anniversary of his death. Pioneer of molecular spectroscopy of microwave, optical pumping and laser spectroscopy, Gozzini was one of the leaders of the last century in the field of atomic physics.
The book reproduces 20 articles written by Adriano Gozzini, including an unpublished preprint, chosen to provide a complete picture of the different topics addressed by the scientist during his scientific career. Each item is associated commentary by scientists who have collaborated with him or international experts on the subject matter, including Nobel laureates C. Cohen-Tannoudji, T.W. Haensch and S. Haroche
Central and peripheral interactions between endocannabinoids and steroids, and implications for drug dependence
No full textEndocannabinoids are biologically active amides, esters and ether of long chain polyunsaturated fatty acids. They interact with several neurotransmitters in the central nervous system (CNS), and with various signaling molecules (including cytokines) in the periphery. Critical interactions have emerged also with steroids, another group of well-known bioactive lipids, both centrally and peripherally. Here, I briefly review the targets of the combined action of endocannabinoids and steroids, and the available evidence concerning the direct regulation by the latter compounds of the proteins of the endocannabinoid system (ES). In addition, I discuss recent examples of endocannabinoids and steroids working together in the central nervous system and in the periphery, which allowed to disclose some molecular details of the interactions between these two groups of lipids. Taken together, available data suggest that steroids can modulate the endocannabinoid tone, through genomic or nongenomic regulation, and that endocannabinoids can complement the biological activity of steroids. In this line, the issues concerning the tissue- and species-specificity of the endocannabinoid-steroid interface, and the possibility that also endocannabinoids may modulate steroid metabolism, are addressed. Finally, I present the hypothesis that retrograde endocannabinoid signaling, by reducing striatal glutamate release, may be part of the molecular events responsible for the influence of steroids on drug abuse. (c) 2005 Elsevier Inc. All rights reserved
Three essays on anti-consumerism, anti-hedonism and environmentalism, and economic growth
No full textRapid environmental changes and technological developments are crucial for sustainable economic growth goals. This dissertation aims to highlight the consequences of firms' and consumers' behavior for society in the presence of external influences exerted by environmental doctrines. In addition, it offers a comparison between machine learning and time series-based methodologies in predicting economic growth. The first chapter delves into the dichotomy between hedonic and environmental attributes of goods in a market characterized by vertical differentiation with heterogeneous consumer preferences. It examines how anti-hedonism and environmentalism influence market outcomes and societal welfare, revealing unexpected harmful effects. A relatively high level of environmental doctrines is detrimental to the ecological surplus. The second chapter explores anti-consumerism, distinguishing between its roles as a psychic reward or cost and its impact on pricing strategies, firm profits, and social welfare within markets for horizontally differentiated goods. The analysis demonstrates that the beneficial societal outcomes are predominantly associated with incentive-based (carrot) approaches rather than punitive (stick) measures. The final chapter compares traditional time series analysis with machine learning, incorporating a variety of economic factors for different strategies in forecasting the real United States Gross Domestic Product (GDP). The K-Nearest Neighbour (KNN) model enhances short-term accuracy predictions. In contrast, linear regression, including financial and macroeconomic factors, enhances long-term accuracy, offering valuable insights for data-driven economic decision-making. This dissertation sheds light on consumer behavior, firms strategies, and predictive modeling, suggesting pathways for more sustainable and informed economic practices
Radiochromatographic assay of N-acyl-phosphatidylethanolamine-specific phospholipase D activity
No full textA radiochromatographic method has been set up to assay the activity of N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), based on reversed-phase high-performance liquid chromatography (HPLC) and online scintillation counting. The anandamide (N-arachidonoylethanolamine, AEA), product released by NAPE-PLD from the N-arachidonoyl-phosphatidylethanolamine (NArPE) Substrate, was separated using a 08 column eluted with methanol-water-acetic acid and was quantified with an external standard method. Baseline separation of AEA and NArPE was completed in less than 15 min, with a detection limit of 0.5 fmol AEA at a signal-to-noise ratio of 4:1. The sensitivity and accuracy of the radiochromatographic procedure allowed detection and characterization of NAPE-PLD activity in very tiny tissue samples or in samples where the enzymatic activity is very low. With this method, we could determine the kinetic constants (i.e., apparent Michaelis-Menten constant (K-m) of 40.0 +/- 5.6 mu M and maximum velocity (V-max) of 22.2 +/- 3.5 pmol/min per milligram protein toward NArPE) and the distribution of NAPE-PLD activity in brain areas and peripheral tissues of mouse. In addition, we could collect unprecedented evidence that compounds widely used in studies of the endocannabinoid system (e.g., AEA and congeners, receptor a(nta)gonists and inhibitors of AEA degradation) can also affect NAPE-PLD activity. (c) 2004 Elsevier Inc. All rights reserved
CRF system involvement in compulsive eating: new cues from pre-clinical rat and C. elegans models
No full textAims: Stress, together with dieting and environmental negative affects is a common trigger of eating disorders, especially binge eating (BE) disorder. The aim of this study was to investigate the regulation of the CRF/CRF-1R-system in a validated rat model of BE and to develop an innovative BE-model in C. elegans, as well as to observe the potential involvement seb-3 gene, similar to the mammalian CRF-1R, on BE behavior.
Methods: Female rats were exposed to food restriction and stress. mRNA abundances and DNA methylation were quantified by qRT-PCR and pyrosequencing. N2 worms and two different seb-3 mutants were exposure to starvation and acute stress, then alterations in feeding activity were recorded.
Results: CRF system is up regulated in the VTA of rats restricted and exposed to stress, and these changes appear to be due to a reduction in DNA methylation at gene promoters. The pharyngeal pumping rate was increased in N2 worms exposed to starvation and stress conditions when compared to animals just starved. Moreover, seb-3 gain-of-function-worms resulted to be more sensitive to the starvation and stress conditions wherever, seb-3 loss-of-function-worms seemed to be not responding.
Conclusions: These data further support the role of CRF-system in compulsive-feeding behavior. Morever, our new proposed BE-model in C. elegans could improve the understanding of the role played by CRF as well as other brain circuits and by environmental triggers in affecting food intake. We believe that this model would give the opportunity to monitor genetic modifications in order to follow disease development easily across worms life-span
Anandamide increases swelling and reduces calcium sensitivity of mitochondria
No full textThe endocannabinoid anandamide alters mitochondria-dependent signal transduction, thus controlling key cellular events like energy homeostasis and induction of apoptosis. Here, the ability of anandamide to directly affect the integrity of mitochondria was investigated on isolated organelles. We found that anandamide dose-dependently increases mitochondrial swelling, and reduces cytochrome c release induced by calcium ions. The effects of anandamide were independent of its target receptors ( e. g., cannabinoid or vanilloid receptors), and were paralleled by decreased membrane potential and increased membrane fluidity. Overall, our data suggest that anandamide can impact mitochondrial physiology, by reducing calcium sensitivity and perturbing membrane properties of these organelles. (C) 2009 Elsevier Inc. All rights reserved
The Endocannabinoids-Microbiota Partnership in Gut-Brain Axis Homeostasis: Implications for Autism Spectrum Disorders
No full textThe latest years have witnessed a growing interest towards the relationship between neuropsychiatric disease in children with autism spectrum disorders (ASD) and severe alterations in gut microbiota composition. In parallel, an increasing literature has focused the attention towards the association between derangement of the endocannabinoids machinery and some mechanisms and symptoms identified in ASD pathophysiology, such as alteration of neural development, immune system dysfunction, defective social interaction and stereotypic behavior. In this narrative review, we put together the vast ground of endocannabinoids and their partnership with gut microbiota, pursuing the hypothesis that the crosstalk between these two complex homeostatic systems (bioactive lipid mediators, receptors, biosynthetic and hydrolytic enzymes and the entire bacterial gut ecosystem, signaling molecules, metabolites and short chain fatty acids) may disclose new ideas and functional connections for the development of synergic treatments combining “gut-therapy,” nutritional intervention and pharmacological approaches. The two separate domains of the literature have been examined looking for all the plausible (and so far known) overlapping points, describing the mutual changes induced by acting either on the endocannabinoid system or on gut bacteria population and their relevance for the understanding of ASD pathophysiology. Both human pathology and symptoms relief in ASD subjects, as well as multiple ASD-like animal models, have been taken into consideration in order to provide evidence of the relevance of the endocannabinoids-microbiota crosstalk in this major neurodevelopmental disorder
THE MEASUREMENT OF THE DEGREE OF CORPORATE SOCIAL RESPONSIBILITY OF A FIRM
No full textThis paper deals with the controversial issue of the congruence/incongruence between the CSR strategies and programs carried out by companies and the expectations of the different categories of stakeholders. In particular, the problem is addressed by comparing the structure of the main ethical rating systems with that of the “internal” CSR performance measurement systems implemented by a sample of large multinational firms operating in different industries. The early results show a great heterogeneity in the set of metrics used. In particular, ethical rating systems seems to be quite inadequate to measure to degree of social responsibility of a compan
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