Search results for "trehalose"

Myo-inositol as a main metabolite in overwintering flies: seasonal metabolomic profiles and cold stress tolerance in a northern drosophilid fly

2012

SUMMARY Coping with seasonal changes in temperature is an important factor underlying the ability of insects to survive over the harsh winter conditions in the northern temperate zone, and only a few drosophilids have been able to colonize sub-polar habitats. Information on their winter physiology is needed as it may shed light on the adaptive mechanisms of overwintering when compared with abundant data on the thermal physiology of more southern species, such as Drosophila melanogaster. Here we report the first seasonal metabolite analysis in a Drosophila species. We traced changes in the cold tolerance and metabolomic profiles in adult Drosophila montana flies that were exposed to thermope…

FTIR and SAXS study on MBCO-saccharide amorphous systems: protein-matrix reciprocal effects

2010

Probing light-induced conformational transitions in bacterial photosynthetic reaction centers embedded in trehalose-water amorphous matrices.

2004

Abstract The coupling between electron transfer and protein dynamics has been studied in photosynthetic reaction centers (RC) from Rhodobacter sphaeroides by embedding the protein into room temperature solid trehalose–water matrices. Electron transfer kinetics from the primary quinone acceptor (Q A − ) to the photoxidized donor (P + ) were measured as a function of the duration of photoexcitation from 20 ns (laser flash) to more than 1 min. Decreasing the water content of the matrix down to ≈5×10 3 water molecules per RC causes a reversible four-times acceleration of P + Q A − recombination after the laser pulse. By comparing the broadly distributed kinetics observed under these conditions …

More than a Confinement: “Soft” and “Hard” Enzyme Entrapment Modulates Biological Catalyst Function

2019

Catalysis makes chemical and biochemical reactions kinetically accessible. From a technological point of view, organic, inorganic, and biochemical catalysis is relevant for several applications, from industrial synthesis to biomedical, material, and food sciences. A heterogeneous catalyst, i.e., a catalyst confined in a different phase with respect to the reagents’ phase, requires either its physical confinement in an immobilization matrix or its physical adsorption on a surface. In this review, we will focus on the immobilization of biological catalysts, i.e., enzymes, by comparing hard and soft immobilization matrices and their effect on the modulation of the catalysts’ function. Indeed, …

Bioprotection Can Be Tuned with Proper Protein/Saccharide Ratio: The Case of Solid Amorphous Matrices

2018

Saccharides, and in particular trehalose, are well known for their high efficiency in protecting biostructures against adverse environmental conditions. The protein dynamics is known to be highly inhibited in a low-water trehalose host medium, the inhibition being markedly dependent on the amount of residual water. Besides hydration, the protein/sugar ratio is expected to affect the properties of saccharide amorphous matrices. In this work, we report an infrared spectroscopy study in dry amorphous matrices of various sugars (the disaccharides trehalose, maltose, sucrose, and lactose, and the trisaccharide raffinose) containing myoglobin, at different protein/sugar ratios. We analyze the str…

Homozygous deletion of ATC1 and NTC1 genes in Candida parapsilosis abolishes trehalase activity and affects cell growth, sugar metabolism, stress res…

2015

A double homozygous atc1Δ/atc1Δ/ntc1Δ/ntc1Δ mutant (atc1Δ/ntc1Δ KO) was constructed in the pathogen opportunistic yeast Candida parapsilosis by disruption of the two chromosomal alleles coding for NTC1 gene (encoding a neutral trehalase) in a Cpatc1Δ/atc1Δ background (atc1Δ KO strain, deficient in acid trehalase). The Cpatc1Δ/ntc1Δ KO mutant failed to counteract the inability of Cpatc1Δ cells to metabolize exogenous trehalose and showed a similar growth pattern on several monosaccharides and disaccharides. However, upon prolonged incubation in either rich medium (YPD) or nutrient-starved medium the viability of Cpatc1Δ cells exhibited a sensitive phenotype, which was augmented by further Cp…

Antioxidant defense parameters as predictive biomarkers for fermentative capacity of active dried wine yeast.

2014

The production of active dried yeast (ADY) is a common practice in industry for the maintenance of yeast starters and as a means of long term storage. The process, however, causes multiple cell injuries, with oxidative damage being one of the most important stresses. Consequentially, dehydration tolerance is a highly appreciated property in yeast for ADY production. In this study we analyzed the cellular redox environment in three Saccharomyces cerevisiae wine strains, which show markedly different fermentative capacities after dehydration. To measure/quantify the effect of dehydration on the S. cerevisiae strains, we used: (i) fluorescent probes; (ii) antioxidant enzyme activities; (ii) in…

Single Molecule Study of GFP-mut2 Proteins Caged in Trehalose-Water Matrixes: Spatially Inhomogeneous Protein-Water-Sugar Structures

2007

Kadmiumaltistuksen havaitseminen Hydropsyche pellucidula -vesiperhostoukilla (Trichoptera: Hydropsychidae) hyperspektrikuvantamisen ja kidusvaurioide…

2017

Metallipäästöt aiheuttavat vesistöissä eliöyhteisöille monenlaisia haittavaikutuksia, joita voidaan tutkia bioindikaattori- eli ilmentäjälajimenetelmin. Vesiperhostoukkia (Trichoptera) on käytetty virtavesien metallisaastumisen indikaattoreina, sillä ne kestävät metallialtistusta suhteellisen hyvin, mutta altistuksen seurauksena toukilla voi esiintyä morfologisia muutoksia, kuten kidusvaurioita tai pintakudoksen tummumista. Koska toisaalta vierasaineiden kudospitoisuusmittaus on usein työlästä ja toisaalta rakenteellisten muutosten arviointi altis subjektiiviselle harhalle, tavoitteenani oli kehittää objektiivinen ja kustannustehokas tapa selvittää metallialtistusta ja sen vaikutuksia pohja…

Calorimetric study of myoglobin embedded in trehalose-water matrixes

2009

It has been suggested that in ‘dry’ protein–trehalose–water systems, water–mediated hydrogen bond network, whose strength increases by drying, anchors the protein to its surroundings. To further characterize this effect, we performed a DSC study on low-water myoglobin–trehalose systems. The denaturation temperature resulted to increase by decreasing hydration, and linearly correlated to the glass transition temperature of both the ternary protein–water–trehalose and the binary water–trehalose systems. Further measurements are being performed to investigate eventual differences among different saccharides.