Search results for "disaccharides"
showing 10 items of 25 documents
An ethoxylated surfactant enhances the penetration of the sulfated laminarin through leaf cuticle and stomata, leading to increased induced resistanc…
2016
International audience; Some β-1,3-glucans and particularly sulfated laminarin (PS3) are known as resistance inducers (RIs) in grapevine against the downy mildew. However, their efficacy in vineyard is still often too low, which might be caused by a limited penetration through the leaf cuticle following spray application. We used (14) C-sucrose uptake experiments with grapevine leaves in order to select a surfactant as saccharide penetration enhancer. Our results showed that though sucrose foliar uptake was low, it was strongly enhanced by Dehscofix CO125 (DE), a highly ethoxylated surfactant. Fluorescent saccharides were then produced and laser scanning microscopy was used to analyze their…
Synthesis of glycopeptides and neoglycoproteins containing the fucosylated linkage region of N-glycoproteins.
1994
Abstract N-Glycoproteins fucosylated in the core region occur in tumor membranes and virus envelopes. Partial structures of such N-glycoproteins containing fucosylated chitobiosyl asparagine conjugates were synthesized using the allyloxycarbonyl (Aloc) and the tert-butyl ester protecting groups in the peptide portion. As the α-fucosidic bond of the conjugates revealed to be very sensitive to acids when carrying ether-type protecting groups, a method for exchanging the protecting groups of the fucose portion of saccharides was developed. Conjugates containing O-acetyl protected fucose proved to be stable against acids used in glycopeptide syntheses. These methods were applied in the synthesi…
Dynamics of the biosynthesis of methylursubin in plant cells employing in vivo 13CNMR without labelling.
1995
Abstract In vivo NMR experiments with a digital 600 MHz instrument, exploiting the natural abundance of 13C, allowed us for the first time to follow the biosynthesis of the newly detected glycoside, methylursubin ( 4- methoxyphenyl -O-β- d -primeveroside ), from 4-methoxyphenol through the intermediate methylarbutin in cell suspensions of the Indian medical plant, Rauwolfia serpentina. The metabolic dynamics indicate that, within 48 hr, 4-methoxyphenol is almost completely converted into the primeveroside, methylursubin. Because of the higher sensitivity at 150.9 MHz compared to that at 100.6 MHz, measuring times could be reduced to 1.5 hr. This allows detailed monitoring of the conversion …
Using NMR in saliva to identify possible biomarkers of glioblastoma and chronic periodontitis
2018
Nowadays there is increasing interest in identifying-and using-metabolites that can be employed as biomarkers for diagnosing, treating and monitoring diseases. Saliva and NMR have been widely used for this purpose as they are fast and inexpensive methods. This case-control study aimed to find biomarkers that could be related to glioblastoma (GBL) and periodontal disease (PD) and studied a possible association between GBL and periodontal status. The participants numbered 130, of whom 10 were diagnosed with GBL and were assigned to the cases group, while the remaining 120 did not present any pathology and were assigned to the control group. On one hand, significantly increased (p < 0.05) meta…
Long-term effects of the trehalase inhibitor trehazolin on trehalase activity in locust flight muscle.
2010
SUMMARY Trehalase (EC 3.2.1.28) hydrolyzes the main haemolymph sugar of insects, trehalose, into the essential cellular substrate glucose. Trehalase in locust flight muscle is bound to membranes that appear in the microsomal fraction upon tissue fractionation, but the exact location in vivo has remained elusive. Trehalase has been proposed to be regulated by a novel type of activity control that is based on the reversible transformation of a latent (inactive) form into an overt (active) form. Most trehalase activity from saline-injected controls was membrane-bound (95%) and comprised an overt form (∼25%) and a latent form (75%). Latent trehalase could be assayed only after the integrity of …
Fate and effects of the trehalase inhibitor trehazolin in the migratory locust (Locusta migratoria).
2009
Abstract Trehalose is the main haemolymph sugar in many insect species. To be utilized trehalose must be hydrolysed into its glucose units by trehalase (EC 3.2.1.28). Inhibitors of trehalase have attracted interest as possible pesticides and tools for studying the regulation of trehalose metabolism in insects. To make full use of these inhibitors requires knowledge of their fate and effects in vivo. To this end we have measured trehazolin in locusts using a method based on the specific inhibition of a trehalase preparation. After injection of 20 μg, trehazolin decreased in haemolymph with a half-life of 2.6 days and after 10 days almost 95% had disappeared. Trehazolin did not reach the intr…
Molecular dynamics simulation of sucrose- and trehalose-coated carboxy-myoglobin
2005
We performed a room temperature molecular dynamics (MD) simulation on a system containing 1 carboxy-myoglobin (MbCO) molecule in a sucrose–water matrix of identical composition (89% [sucrose/(sucrose + water)] w/w) as for a previous trehalose–water–MbCO simulation (Cottone et al., Biophys J 2001;80:931–938). Results show that, as for trehalose, the amplitude of protein atomic mean-square fluctuations, on the nanosecond timescale, is reduced with respect to aqueous solutions also in sucrose. A detailed comparison as a function of residue number evidences mobility differences along the protein backbone, which can be related to a different efficacy in bioprotection. Different heme pocket struc…
Thermal denaturation of myoglobin in water--disaccharide matrixes: relation with the glass transition of the system.
2009
Proteins embedded in glassy saccharide systems are protected against adverse environmental conditions [Crowe et al. Annu. Rev. Physiol. 1998, 60, 73-103]. To further characterize this process, we studied the relationship between the glass transition temperature of the protein-containing saccharide system (T(g)) and the temperature of thermal denaturation of the embedded protein (T(den)). To this end, we studied by differential scanning calorimetry the thermal denaturation of ferric myoglobin in water/disaccharide mixtures containing nonreducing (trehalose, sucrose) or reducing (maltose, lactose) disaccharides. All the samples studied are, at room temperature, liquid systems whose viscosity …
Initial topical cooling followed by backtable Celsior flush perfusion provides excellent early graft function in porcine single lung transplantation …
2013
Topical in situ cooling of the donor lungs is a prerequisite for procurement of non-heart-beating donor lungs and may be of interest for living related lung donation.Twenty-four single lung transplants were performed in 4 groups of Landrace pigs (6 per group). Control LPD, control Celsior and topical cooling in situ, followed by LPD (exLPD) or Celsior (exCel) ex situ flush, were employed. All lungs were perfused antegrade with 1 liter of solution at 4°C. Lungs were stored immersed in preservation solution for 24 hours at 4°C. After transplantation of the left lung, the right recipient bronchus and pulmonary artery were clamped.Four of 6 animals each in the LPD and Celsior groups and all 6 a…
SAXS Study on Myoglobin Embedded in Amorphous Saccharide Matrices
2011
We report on Small Angle X-ray Scattering (SAXS) measurements performed on samples of carboxy-myoglobin and met-myoglobin embedded in low hydrated matrices of four different saccharides (trehalose, sucrose, maltose and lactose). Results confirm the already reported occurrence of inhomogeneities, which are not peculiar of trehalose samples, but appear also in maltose and lactose, and in some cases also sucrose, being dependent on the sample hydration and on the presence of sodium dithionite. This behaviour confirms our previous interpretation about the nature of the inhomogeneities, and prompt it as a possible general behaviour for highly concentrated sugar matrices.