Search results for "Raffinose"

Identification of Putative Interactors of Arabidopsis Sugar Transporters

2020

International audience; Hexoses and disaccharides are the key carbon sources for essentially all physiological processes across kingdoms. In plants, sucrose, and in some cases raffinose and stachyose, are transported from the site of synthesis in leaves, the sources, to all other organs that depend on import, the sinks. Sugars also play key roles in interactions with beneficial and pathogenic microbes. Sugar transport is mediated by transport proteins that fall into super-families. Sugar transporter (ST) activity is tuned at different levels, including transcriptional and posttranslational levels. Understanding the ST interactome has a great potential to uncover important players in biologi…

Flower abscission in Vitis vinifera L. triggered by gibberellic acid and shade discloses differences in the underlying metabolic pathways

2015

Understanding abscission is both a biological and an agronomic challenge. Flower abscission induced independently by shade and gibberellic acid (GAc) sprays was monitored in grapevine (Vitis vinifera L.) growing under a soilless greenhouse system during two seasonal growing conditions, in an early and late production cycle. Physiological and metabolic changes triggered by each of the two distinct stimuli were determined. Environmental conditions exerted a significant effect on fruit set as showed by the higher natural drop rate recorded in the late production cycle with respect to the early cycle. Shade and GAc treatments increased the percentage of flower drop compared to the control, and …

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…

A Good Breath of Oxygen for Beta-Like Cells Obtained From Porcine Exocrine Pancreatic Tissue

2011

Ischemia is the most important factor that affects organ survival during harvesting. The two-layer method (TLM) is one of several cold storage solutions that seeks to preserve organs and cells avoiding in vivo and in vitro ischemia. We compared the retrieval of beta-like elements from exocrine pancreatic cells using TLM versus University of Wisconsin (UW) solutions. For this purpose pancreata laparoscopically harvested from 20 female pigs were preserved in UW solution or TLM before digestion. The resulting exocrine cells were divided into 2 groups: the first was cultured in a designed medium to allow differentiation into beta-like cells and the second was cryopreserved before the differenti…

Prevention of ischemic-type biliary lesions by arterial back-table pressure perfusion

2003

Abstract Ischemic-type biliary lesions (ITBLs) lead to considerable morbidity after orthotopic liver transplantation (OLT). The exact pathogenesis is unknown. We tested the hypothesis that insufficient perfusion of biliary arterial vessels might be responsible for ITBLs. This could be prevented by improved perfusion techniques. Since February 2000, we performed a controlled study using arterial back-table pressure perfusion (AP) to achieve reliable perfusion of the biliary-tract capillary system, which may be impaired by the high viscosity of University of Wisconsin solution. We retrospectively analyzed 190 OLTs performed between September 1997 and July 2002 with regard to ITBLs. One hundre…

Destruction of Kupffer’s cells increases total liver blood flow and decreases ischemia reperfusion injury in pigs

2000

Role of two operators in regulating the plasmid-borne raf operon of Escherichia coli

1994

The plasmid-borne raf operon encodes functions required for the inducible uptake and utilization of raffinose in Escherichia coli K12. The expression of three structural genes for alpha-galactosidase (rafA), Raf permease (rafB) and sucrose hydrolase (rafD) is negatively controlled by the binding of RafR repressor (rafR) to two operator sites, O1 and O2, that flank the -35 sequence of the raf promoter, PA. In vitro, O1 and O2 are occupied on increasing the concentration of RafR, without detectable preference for one site or the other or any indication of cooperative binding. Nucleotide substitutions at positions 3, 4 or 5 in an operator half-site prevented repressor binding, supporting a mod…

Formation of Levan from Raffinose by Levansucrase ofZymomonas mobilis

2004

Levansucrase (EC 2.4.1.10.) of Zymomonas mobilis 113S can perform the polymerisation of fructose moiety from raffinose to levan concomitantly with a release of non-catabolised melibiose into the medium. The kinetic parameters of the levansucrase-catalysed reaction provide even higher reaction velocities on raffinose as compared to sucrose, particularly at low substrate concentrations. A decreased value in the number of the average molecular mass (Mn = 1693 kDa), an increased intrinsic viscosity (η = 49.47 cm3/g), and a diminished Huggin's constant (K' = 0.67) are intrinsic to the levan synthesis from raffinose, indicating certain structural peculiarities compared to a polysaccharide obtaine…

Carbohydrate binding specificity and purification by biospecific affinity chromatography of Ascidiamalaca traust. Hemagglutinins

1982

The carbohydrate specificities of Ascidia malaca serum hemagglutinins were determined by hemagglutination inhibition tests. Analysis of agglutinins against rabbit and human A, B, O erythrocytes suggests that the size of the combining site corresponds to a disaccharide with a specificity for saccharides containing a D-galacto configuration (D-melibiose, D-raffinose, D-galactose, alpha-lactose, lactulose, L-arabinose). No anomeric specificity was observed with oligosaccharides. Hydroxyl groups probably involved in hydrogen-bond formation with agglutinin binding site, were identified as carbons C2, C4, C5 and C6 of D-galactose. Absorption experiments showed that two distinct agglutinins with s…

Role of Solvent on Protein-Matrix Coupling in MbCO Embedded in Water-Saccharide Systems: A Fourier Transform Infrared Spectroscopy Study

2006

AbstractEmbedding protein in sugar systems of low water content enables one to investigate the protein dynamic-structure function in matrixes whose rigidity is modulated by varying the content of residual water. Accordingly, studying the dynamics and structure thermal evolution of a protein in sugar systems of different hydration constitutes a tool for disentangling solvent rigidity from temperature effects. Furthermore, studies performed using different sugars may give information on how the detailed composition of the surrounding solvent affects the internal protein dynamics and structural evolution. In this work, we compare Fourier transform infrared spectroscopy measurements (300–20K) o…