In vitro starch binding experiments: Study of the proteins related to grain hardness of wheat

Two friabilin components, puroindoline a and GSP-1 were expressed in Escherichia coli. Starch binding properties of the recombinant polypeptides and of friabilin extracted from wheat flour were compared in vitro. The produced proteins as well as native wheat friabilin bound to starch granules prepared from different (soft, hard and durum) wheat cultivars. Starch granules also bound specifically several wheat endosperm proteins other than friabilin

On Dipole Moments and Hydrogen Bond Identification in Water Clusters

It is demonstrated that the localized orbitals calculated for a water cluster have small delocalization tails along the hydrogen bonds, that are crucial in determining the resulting dipole moments of the system. (By cutting them, one gets much smaller dipole moments for the individual monomersclose to the values one obtains by using a Bader-type analysis.) This means that the individual water monomers can be delimited only in a quite fuzzy manner, and the electronic charge density in a given point cannot be assigned completely to that or another molecule. Thus, one arrives to the brink of breaking the concept of a water cluster consisting of individual molecules. The analysis of the tails of the localized orbitals can also be used to identify the pairs of water molecules actually forming hydrogen bonds

Potassium acetate solution as a promising option to osmotic distillation for sour cherry (Prunus cerasus L.) juice concentration

Different osmotic agents (OA), such as potassium acetate (CH3COOK), potassium carbonate (K2CO3) and ammonium nitrate (NH4NO3), have been examined as alternatives to the traditionally used calcium chloride (CaCl2) for osmotic distillation concentrating of clarified and pre-concentrated sour cherry (Prunus cerasus L.) juice. Comparison of the process performances based on the permeate fluxes has been carried out. Regarding the permeate flux results, simplified estimation of the overall mass transfer coefficient of the most effective osmotic agent and the reference (CaCl2) solution has been also performed. Furthermore, analytical methods such as total antioxidant activity (TAA) and total polyphenolic content (TPC) using spectrophotometric assays have been also carried out to evaluate the effect of the osmotic distillation on the valuable compounds content of concentrated sour cherry juice. CH3COOK was found to be the most effective, resulted more than 25% higher permeate flux during the sour cherry juice concentration. K2CO3 and NH4NO3 were less effective. The simplified mass transfer estimation showed that the CH3COOK is more effective only at near saturated concentrations compared to the CaCl2. Regarding the TAA and TPC contents, a significant loss was found in case of all OAs during the concentration procedures

The Agrobacterium VirE3 effector protein: a potential plant transcriptional activator

During the infection of plants, Agrobacterium tumefaciens introduces several Virulence proteins including VirE2, VirF, VirD5 and VirE3 into plant cells in addition to the T-DNA. Here, we report that double mutation of virF and virE3 leads to strongly diminished tumor formation on tobacco, tomato and sunflower. The VirE3 protein is translated from a polycistronic mRNA containing the virE1, virE2 and virE3 genes, in Agrobacterium. The VirE3 protein has nuclear localization sequences, which suggests that it is transported into the plant cell nucleus upon translocation. Indeed we show here that VirE3 interacts in vitro with importin-α and that a VirE3–GFP fusion protein is localized in the nucleus. VirE3 also interacts with two other proteins, viz. pCsn5, a component of the COP9 signalosome and pBrp, a plant specific general transcription factor belonging to the TFIIB family. We found that VirE3 is able to induce transcription in yeast when bound to DNA through the GAL4-BD. Our data indicate that the translocated effector protein VirE3 is transported into the nucleus and there it may interact with the transcription factor pBrp to induce the expression of genes needed for tumor development

Adhesion of alumina surfaces through confined water layers containing various molecules

When two surfaces confine water layers between them at the nanoscale, the behaviour of these confined water molecules can deviate significantly from the behaviour of bulk water and it could reflect on the adhesion of such surfaces. Thus, the aim of this study is to assess the role of confined water layers on the adhesion of hydrophilic surfaces and how sensitive this adhesion is to the presence of contaminants. Our methodology used under water AFM force measurements with an alumina sputtered sphere-tipped cantilever and a flat alumina single crystal, then added fractions of ethanol, dimethylformamide, formamide, trimethylamine, and trehalose to water, as contaminants. Such solutions were designed to illuminate the influences of dielectric constant, molecular size, refractive index and number of hydrogen bonds from donors and acceptors of solutes to water. Apart from very dilute solutions of dimethylformamide, all solutions decreased the ability of confined water to give adhesion of the alumina surfaces. The predicted theoretical contribution of van der Waals and electrostatic forces was not observed when the contaminants distorted the way water organizes itself in confinement. The conclusion was that adhesion was sensitive mostly to hydrogen bonding network within water layers confined by the hydrophilic alumina surfaces