PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 16849211

Inelastic neutron scattering study on bioprotectant systems.

S Magazù·F Migliardo·A J Ramirez-Cuesta
View original source ↗Export metadata ↓

Abstract

We collected inelastic neutron scattering (INS) spectra of homologous disaccharide (C12H22O11)/H2O mixtures at a very low temperature by using indirect geometry time-of-flight spectrometer TOSCA at the ISIS pulse neutron facility (DRAL, UK). The aim of this work is to investigate the vibrational behaviour of trehalose, maltose and sucrose/H2O mixtures with INS in order to characterize the structural changes induced by these disaccharides on the H2O hydrogen-bonded network. A higher degree of 'crystallinity' for the trehalose/H2O system is observed in the vibrational region corresponding to the ice bending modes. This feature could justify the better cryptobiotic action of trehalose compared with maltose and sucrose. On the other hand, the better bioprotective effectiveness could be explained by the higher destructuring effect of trehalose, emphasized by the analysis of the librational modes region.

Explore related subjects

Cryoprotective AgentsDisaccharidesElasticityNeutron DiffractionWaterJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S Magazù, F Migliardo, A J Ramirez-Cuesta. 2005-12-22. Inelastic neutron scattering study on bioprotectant systems.. https://doi.org/10.1098/rsif.2005.0059

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Concentration dependence of vibrational properties of bioprotectant/water mixtures by inelastic neutron scattering.

Neutron scattering has been demonstrated to be a powerful tool for characterizing the structure and dynamics of biological molecules and for investigating the physical and chemical mechanisms of biophysical processes. The aim of the present work is to investigate by inelastic neutron scattering (INS) the vibrational behaviour of a class of bioprotectant systems, such as homologous disaccharides, trehalose, maltose and sucrose, in water mixtures. INS measurements have been performed on trehalose/H2O, maltose/H2O and sucrose/H2O mixtures at very low temperature as a function of concentration by using the thermal original spectrometer with cylindrical analyzers (TOSCA) spectrometer at the ISIS Facility (DRAL, UK). The findings allow the analyses of the vibrational features of the INS spectra in order to study the effect of disaccharides on the H2O hydrogen-bonded tetrahedral network. The obtained neutron scattering findings point out that disaccharides, and in particular trehalose, have a destructuring effect on the water tetrahedral network, as emphasized by the analysis of the librational modes region from 50 to 130 meV energy transfer. On the other hand, the analysis of the bending modes region (130-225 meV) shows a locally ordered structure in the disaccharide/H2O mixtures.Finally, the observed experimental evidences are linked to the different bioprotective effectiveness of disaccharides as a function of concentration.

Cryoprotective Agents↗
PubMed2007

Cryocrystallography of macromolecules: practice and optimization.

Techniques for flash-cooling protein crystals to around 100K (-173 degrees C) for data collection have developed enormously in the last decade, to the extent that cryocrystallography is now standard practice. The main advantage of these methods is the vastly reduced rate of radiation damage to protein crystals in the X-ray beam at cryogenic temperatures over room temperature, extending their lifetimes so that complete datasets can be collected from a single crystal. The practical application of the techniques has become somewhat anecdotal and rather fixed within individual laboratories. This chapter gives step-by-step guidelines for flash-cooling crystals and some of the rationale for the recommended procedures. Optimization of the entire cryoprotocol can give substantial improvements to both the resolution and quality of the data, often resulting in more straight-forward structure solution and subsequent model refinement. Attention to seemingly insignificant details can have a real impact on the usefulness of the final dataset, and are thus worth addressing.

Cryoprotective Agents↗
PubMed2006

Optimisation and comparison of liquid and dry formulations of the biocontrol yeast Pichia anomala J121.

The biocontrol yeast Pichia anomala J121 can effectively reduce mould growth on moist cereal grains during airtight storage. Practical use of microorganisms requires formulated products that meet a number of criteria. In this study we compared different formulations of P. anomala. The best way to formulate P. anomala was freeze-drying. The initial viability was as high as 80%, with trehalose previously added to the yeast. Freeze-dried products could be stored at temperatures as high as 30 degrees C for a year, with only a minor decrease in viability. Vacuum-drying also resulted in products with high storage potential, but the products were not as easily rehydrated as freeze-dried samples. Upon desiccating the cells using fluidised-bed drying or as liquid formulations, a storage temperature of 10 degrees C was required to maintain viability. Dependent on the type of formulation, harvesting of cells at different nutritional stresses affected the initial viabilities, e.g. the initial viability for fluidised-bed-dried cells was higher when the culture was fed with excess glucose, but for freeze-drying it was superior when cells were harvested after depletion of carbon. Using micro-silos we found that the biocontrol activity remained intact after drying, storage and rehydration for all formulations.

Cryoprotective Agents↗