1,721,140 research outputs found
ISOTHERMAL TITRATION CALORIMETRY: FROM BIOMOLECULES TO MICROORGANISMS
No full textThe modern microcalorimetry revolution was sustained by the availability of sensitive commercial instruments and two calorimetric methods, differential scanning calorimetry (DSC) and isothermal scanning calorimetry (ITC), that nowadays are dominant in the studies of biological macromolecules.
In the case of bio macromolecules in diluted solution details about the thermodynamics of the interaction with ligands (affinity constant, interaction enthalpy and entropy, cooperativity, allosteric effects, etc.) can be drawn from ITC investigations.
Furthermore ITC represents a powerful method to monitor directly the biological activity of living cells and/or microorganisms since provide direct quantitative information both on the energetic and kinetic behavior of the general metabolism.
However we may mention that the ITC approach applied in biological systems must be intended more as “investigation” than “analytical” methods. Peculiar thermodynamic methods and personnel training on data analysis is demand for the optimum exploitation of these methods in the biological research
Isothermal Titration Calorimetry: From Biomolecules to Microorganisms
No full textThe modern microcalorimetry revolution was sustained by the availability of sensitive commercial instruments and two calorimetric methods, differential scanning calorimetry (DSC) and isothermal scanning calorimetry (ITC), that nowadays are dominant in the studies of biological macromolecules.
In the case of bio macromolecules in diluted solution details about the thermodynamics of the interaction with ligands (affinity constant, interaction enthalpy and entropy, cooperativity, allosteric effects, etc.) can be drawn from ITC investigations.
Furthermore ITC represents a powerful method to monitor directly the biological activity of living cells and/or microorganisms since provide direct quantitative information both on the energetic and kinetic behavior of the general metabolism.
However we may mention that the ITC approach applied in biological systems must be intended more as “investigation” than “analytical” methods. Peculiar thermodynamic methods and personnel training on data analysis is demand for the optimum exploitation of these methods in the biological research
Classical and Knudsen Thermogravimetry to check States and Displacements of Water in Food Systems
No full textWater states and displacements can be investigated with thermogravimetry (TG) either in its classical or in the Knudsen version (where standard pans are replaced with Knudsen cells). The case of wheat flour dough is considered in various steps of bread making, namely, mixing, proofing, baking, staling. The split of DTG signals into various components (gaussian functions) support the assumption that the overall dough water is partitioned into various fractions. Few comments are devoted to water displacements during freezing
Calorimetry and thermal analysis in food science : an updated review
Full text linkFood science is a domain of life science. Applications of thermal analysis and calorimetry (TAC) to food products deal with many investigation targets spanning from the characterization of the systems at molecular and supramolecular level to the description of the microbial metabolism. Food products are multi-phase and multi-component metastable systems where several processes can occur simultaneously during the preparation process and the shelf life. One therefore has to disentangle various contributions to the overall instrumental outputs, using appropriate data treatments and kinetic models, and/or results from other experimental approaches. The paper reports an updated survey of TAC applications to food products through specific examples of data treatments
Calorimetric study of new model cell membranes to assess the influence of food fatty acids and Ca2+ in the frame of T2DM onset and progression
No full textL’obiettivo di questo progetto di tesi di dottorato è quello di preparare e caratterizzare (termodinamicamente e spettroscopicamente) delle membrane modello che simulino al meglio i doppi strati fosfolipidici delle cellule β di Langerhans al fine di comprendere gli effetti della composizione lipidica e dello stress di origine alimentare (alte concentrazioni di Ca2+ e FFA) sulla stabilità di membrana. La successiva interazione di hIAPP con le membrane modello aiuterà a comprendere il peso della stabilità delle membrane cellulari nella patogenesi del T2DM.The aim of this PhD thesis research project is to prepare and characterize (thermodynamically and spectroscopically) model membranes which simulate as possible the phospholipid bilayers of the Langerhans β-cells in order to understand the effects of the lipid composition and the action of foodborne stress (high Ca2+ and FFA concentrations) on membrane stability. Furthermore, the interaction between these model membranes and hIAPP will be studied in order to highlight the role of cell membrane stability on the pathogenesis of T2DM
Moderne tecnologie per il rilevamento dell' inquinamento costiero e dello stato di dispersione delle acque interne superficiali
No full textThermodynamic Assessment of the Interaction of Food Fatty Acids with Pancreatic Model Membranes: Links Between Obesity and T2DM
No full textIl presente lavoro ha avuto come obiettivo la realizzazione e lo studio calorimetrico di membrane cellulari modello allo scopo di simulare al meglio le membrane delle cellule β di Langerhans. In particolare ci si è focalizzati sull’influenza della composizione e delle dimensioni di tali membrane sulla loro stabilità. La successiva aggiunta di tre acidi grassi liberi (FFAs) alimentari, la quale mira a riprodurre l’effetto dell’elevata concentrazione ematica di FFAs tipica dei soggetti obesi e/o affetti da Diabete Mellito di Tipo 2 (T2DM) sul doppio strato fosfolipidico cellulare, ha permesso di evidenziarne e quantificarne gli effetti termodinamici su tali sistemi in relazione alla natura dell’acido.The aim of this work was the preparation and the calorimetric study of model cell membranes in order to simulate as best as possible the Langerhans β-cells’ membranes. Specifically, it was focused on the influence of the composition and the size of such model membranes on their stability. The consequent addition of three food Free Fatty Acids (FFAs), which aims to mimic the effect of high blood FFAs concentration typical of obese subjects and/or ones affected by Type 2 Diabetes Mellitus (T2DM) on the cell phospholipid bilayers, allowed to highlight and quantify their thermodynamic effects on such systems in relation to the nature of the acids
Calorimetric approach to biomembrane thermodynamics: spotting the key points
No full textThe investigation of the forces that drive the self-assembly of phospholipid bilayers and that induce a particular thermodynamic behaviour is crucial for the determination of their roles in biological environments. For this reason, proper consideration should be paid to both endogenous and exogenous factors involved in biomembrane stability.
In this frame, a stepwise study of vesicles with different morphology and lipid composition was performed through high-sensitivity differential scanning calorimetry at physiological pH with the purpose of comprehending the role played by some of the main factors that contribute to the thermodynamic stability of cell membranes, e.g., lamellarity, curvature, phospholipid/non-phospholipid composition [1,2].
The nature and the magnitude of the effects arising from the interaction of lipid membranes with several external agents, such as proteins, lipids and other compounds, have also been evaluated in different case studies [3,4]. The high sensitivity of the DSC technique in revealing modifications in membrane thermodynamic stability is noteworthy for gaining insights on molecular aspects of the interaction mechanism, leading to several applications in biological, food and pharmaceutical fields
Metabolic risk of new food technologies: calorimetric study of model cell membranes for the determination of the influence of free fatty acids (FFA) in diabetes mellitus onset
Full text linkType 2 diabetes mellitus (T2DM) is a chronic disease that continues to spread in both developed and developing countries. Indeed, the individuals affected by diabetes mellitus (type 1 and type 2) in the world are now close to 400 million and estimates suggest that they will reach 600 million by 2035.
The rapid spreading of this disorder is influenced not only by genetic factors but also by environmental ones: socio-economic variations, evolution of lifestyle and changes in dietary habits have contributed to increase the percentage of overweight and obese individuals, which in turn have led to a greater diffusion of diabetes. In fact, weight gain is closely related to insulin-resistance onset, which is considered as the starting point for the development of the disease. However, the manner in which obesity and nutrition factors are linked to the onset of T2DM is not fully understood yet, especially at a molecular level.
The aim of the project presented here is to prepare and characterize (thermodynamically and spectroscopically) model membranes which simulate as possible the phospholipid bilayers of the Langerhans β-cells in order to highlight and discriminate the role of the lipid composition and foodborne stress (in terms of [Ca2+] and [FFA]) in the membrane stability. Moreover, the interaction between the model membrane and hIAPP, which seems to be involved in β-cells death, will be used to evaluate the influence of membrane stability on T2DM onset
- …
