fragility of bioprotectant glass forming systems in extremophiles

A central issue in the adaptation of proteins and enzymes to extreme conditions is the conservation of their functional state, which is characterized by a well-balanced compromise of stability and flexibility. In this review work an overview of elastic neutron scattering (ENS) findings on a class of bioprotectant glass-forming systems, such as trehalose and its homologous (maltose and sucrose) water mixtures, is presented as a function of temperature and concentration. ENS, in fact, allows to determine some remarkable quantities in order to characterize the correlation among dynamical properties, the flexibility and fragility of biomolecules. The experimental results have pointed out a dynamical transition, which shows a crossover in molecular fluctuations between harmonic and anharmonic dynamical regimes. The ENS findings allow to characterize both the trehalose rigidity and flexibility, which are strictly connected to its superior bioprotective effectiveness. In this frame the lowest flexibility and fragility character of trehalose/H2Omixture with respect to maltose and sucrose/H2Omixtures indicate a better attitude to encapsulate biostructures in more rigid and temperature insensitive structures in approaching the glass transition

Electromagnetic Fields Effects on the Secondary Structure of Lysozyme and Bioprotective Effectiveness of Trehalose

FTIR spectroscopy was used to investigate the effects of extremely low frequency (50 Hz) electromagnetic field and of microwaves at 900 MHz on the secondary structure of a typical protein, the lysozyme, evaluating the bioprotective effectiveness of trehalose. Lysozyme in D2O solution (60 mg/ml) was exposed to 50 Hz frequency electromagnetic field at 180 μT. The FTIR spectra indicated an increase of CH2 group at 1921 and 1853 cm−1 after 3 h of exposure. Such effect was not observed after the addition of trehalose (150 mg/mL) at the same exposure conditions. Lysozyme dissolved in D2O at the concentration of 100 mg/mL was exposed up to 4 h to 900 MHz mobile phone microwaves at 25 mA/m. A significant increase in intensity of the amide I vibration band in the secondary structure of the protein was observed after 4 h exposure to microwaves. This effect was inhibited by the presence of trehalose at the concentration of 150 mg/mL. Fourier self-deconvolution spectral analysis of lysozyme in D2O solution after exposure to microwaves revealed an increase in intensity of the conformational components of amide I mode, particularly of β-sheet and turn that can be attributed to disorder and unfolding processes of the protein

Demicellization of Polyethylene Oxide in Water Solution under Static Magnetic Field Exposure Studied by FTIR Spectroscopy

FTIR spectroscopy was used to investigate the alterations of the vibration bands in the mid-infrared region of Polyethylene oxide in aqueous solution at 25 mg/mL concentration under exposure up to 4 h to a static magnetic field at 200 mT. FTIR spectroscopic analysis of PEO solution in the range 3500–1000 cm−1 evidenced the stretching vibrations of ether band, C–H symmetric-antisymmetric and bending vibrations of methylene groups, and the C–O–C stretching band. A significant decrease in intensity of symmetric and asymmetric stretching CH2 vibration bands occurred after 2 h and 4 h of exposure, followed by a significant decrease in intensity of scissoring bending in plane CH2 vibration around 1465 cm−1. Finally, the C–O–C stretching band around 1080 cm−1 increased in intensity after 4 h of exposure. This result can be attributed to the increase of formation of the intermolecular hydrogen bonding that occurred in PEO aqueous solution after SMF exposure, due to the reorientation of PEO chain after exposure to SMF. In this scenario, the observed decrease in intensity of CH2 vibration bands can be understood as well considering that the reorientation of PEO chain under the applied SMF induces PEO demicellization

Proteins in aqueous solution under high frequency electromagnetic field: viscoelastic approximation of a complex system

Proteins in aqueous solution are complex systems that are made of many interacting and non-interacting elements whose behavior can be predictable upon the application of non-linear models. The aim of this study was to show that this complex system behaves like a viscoelastic system under exposure to high frequency electromagnetic (HF-EMF). To this aim, typical proteins in water solution were exposed for 3 h to a high frequency electromagnetic field at the power density of 1 W/m2.  Proteins α-helices aligned along the direction of the field and the integrated areas of proteins β-sheet content increased linearly as a function of proteins dipole moment. This result can be explained assuming that proteins in aqueous solution under HF-EMF behave like a viscoelastic system

Interactions of Bovine Muscle Tissue with 2450 MHz Microwaves Studied in the Mid-Infrared Region

The effects of microwaves at 2450 MHz at 600 W on bovine muscle tissue have been studied by means of Fourier transform infrared spectroscopy. Spectral analysis in the amide I region after microwave cooking showed that an increase in intensity occurred in the region around 1665 and 1695 cm–1, that can be attributed to β-turns and β-sheet features, respectively. This result characterized disorder processes in the protein. In addition, CH2 methylene and carbonyl band vibrations of samples under exposure to microwave heating appeared lower than vibrations of samples heated by conventional oven. This result demonstrated that the Maillard reaction occurs partially after cooking by microwave oven

Study of convective motions and analysis of the impact of physical parametrization on the WRF-ARW forecast model

Optimizing the physical parametrizations of the Weather Research and Forecasting (WRF) model is one of the most challenging and complex tasks. In fact, it is not a simple operation to optimize the performance of a meteorological model capable of forecasting meteorological events, even extreme ones, in complex orographic areas such as that of Sicily. In this reference framework, the research activity of the group of meteorology and environmental modeling, established at the Department of Mathematics and Computer Sciences, Physical Sciences and Earth Sciences (MIFT) of the University of Messina, focuses on the development of a physical-mathematical model for the meteorological forecast. The WRF prediction model is evaluated on the ability to predict the development and evolution of a thunderstorm cell. After the definition of the domain under study and the choice of spatial resolution to be used, it was proceeded to the optimization of the physical  parametrizations. In particular, in this paper, the performance improvements of the WRF model were evaluated, obtained by optimizing the convective parametrizations. As a case study, the meteorological event recorded in Sicily on 9 June 2016 was examined

Upgrading of Resolution Elastic Neutron Scattering (RENS)

An update of the Resolution Elastic Neutron Scattering (RENS) approach consisting in measuring the elastically scattered neutron intensity versus the instrumental energy resolution is presented. In particular it is shown that the measured elastic scattering law as a function of the logarithm of the instrumental energy of resolution gives rise to an increasing sigmoid trend whose inflection point can be connected with the system relaxation time. The validity of the RENS approach is supported by a numerical simulation, taking into account a Gaussian resolution function and a Lorentzian scattering law, and experimentally by integrated EINS and QENS measurements performed as a function of temperature on three homologous disaccharide/water mixtures showing different relaxation times. Furthermore, the most important advantages of the RENS approach are discussed; in particular, in comparison with QENS, the RENS approach requires a smaller amount of sample, which is an important point in dealing with biological and exotic systems, is not affected by the use of model functions for fitting spectra, and furnishes a direct access to the system relaxation time

Amphiphiles Self-Assembly: Basic Concepts and Future Perspectives of Supramolecular Approaches

Amphiphiles are synthetic or natural molecules with the ability to self-assemble into a wide variety of structures including micelles, vesicles, nanotubes, nanofibers, and lamellae. Self-assembly processes of amphiphiles have been widely used to mimic biological systems, such as assembly of lipids and proteins, while their integrated actions allow the performance of highly specific cellular functions which has paved a way for bottom-up bionanotechnology. While amphiphiles self-assembly has attracted considerable attention for decades due to their extensive applications in material science, drug and gene delivery, recent developments in nanoscience stimulated the combination of the simple approaches of amphiphile assembly with the advanced concept of supramolecular self-assembly for the development of more complex, hierarchical nanostructures. Introduction of stimulus responsive supramolecular amphiphile assembly-disassembly processes provides particularly novel approaches for impacting bionanotechnology applications. Leading examples of these novel self-assembly processes can be found, in fact, in biosystems where assemblies of different amphiphilic macrocomponents and their integrated actions allow the performance of highly specific biological functions. In this perspective, we summarize in this tutorial review the basic concept and recent research on self-assembly of traditional amphiphilic molecules (such as surfactants, amphiphile-like polymers, or lipids) and more recent concepts of supramolecular amphiphiles assembly which have become increasingly important in emerging nanotechnology

Study of the Boson Peak and Fragility of Bioprotectant Glass-Forming Mixtures by Neutron Scattering

The biological relevance of trehalose, glycerol, and their mixtures in several anhydrobiotic and cryobiotic organisms has recently promoted both experimental and simulation studies. In addition, these systems are employed in different industrial fields, such as pharmaceutical and cosmetic industries, as additives in mixtures for cryopreservation and in several formulations. This review article shows an overview of Inelastic Neutron Scattering (INS) data, collected at different temperature values by the OSIRIS time-of-flight spectrometer at the ISIS Facility (Rutherford Appleton Laboratory, Oxford, UK) and by the IN4 and IN6 spectrometers at the Institut Laue Langevin (ILL, Grenoble, France), on trehalose/glycerol mixtures as a function of the glycerol content. The data analysis allows determining the Boson peak behavior and discussing the findings in terms of fragility in relation to the bioprotective action of trehalose and glycerol