Peroxidase catalyzed conjugation of peptides, proteins and polysaccharides via endogenous and exogenous phenols.

The research was directed towards peroxidase mediated cross-linking of proteins and polysaccharides. Two approaches were explored, cross-linking by use of ferulic acid (FA)oand cross-linking by use of catechol. Within each approach, first model studies were performed with small peptides, of which the findings were applied in subsequent studies with proteins. First, a kinetically controlled incubation that leads to covalently coupled adducts of the tripeptide Gly-Tyr-Gly (GYG) and FA, catalyzed by horseradish peroxidase (HRP) is described. Next, two series of covalent adducts of GYG and FA, comprising dehydrogenatively polymerized FA on the GYG tyrosine were identified. Cross-linking of holo- and apo‑a‑lactalbumin was subsequently explored. Oligomerization ofa‑lactalbumin was observed and a direct relation between protein conformation and extent of oligomerization was shown. Application of the findings with GYG, combined with those ofa-lactalbumin homo-cross-linking ledto the modification ofa-lactalbumin with FA. The degree of polymerization ofa-lactalbumin was reciprocal to the incident concentration of free FA. Next, cross-linking of FA-containing arabinoxylans withb-casein is described. Maximal formation of protein-arabinoxylan conjugates were formed at high protein to arabinoxylan ratios in combination with a low H 2 O 2 concentration and a long reaction time. Finally, the use of catechol in peroxidase catalyzed modification of aminoacids andproteins was studied . Covalent attachment of catechol to the side chain of the amino acids tyrosine and histidine was unambiguously proven by tandem MS ofthe adducts. Cross-linking of globular proteins yielded oligomeric adducts whereas cross-linking ofb-casein yielded high molecular weight polymers. Two mechanisms for the cross-linking of catechol with proteins were proposed

Label-free mass spectrometry-based proteomics for biomarker discovery and validation in tissues and biofluids

Comunicaciones a congreso

Selected reactive oxygen species and antioxidant enzymes in common bean after Pseudomonas syringae pv. phaseolicola and Botrytis cinerea infection

Phaseolus vulgaris cv. Korona plants were inoculated with the bacteria Pseudomonas syringae pv. phaseolicola (Psp), necrotrophic fungus Botrytis cinerea (Bc) or with both pathogens sequentially. The aim of the experiment was to determine how plants cope with multiple infection with pathogens having different attack strategy. Possible suppression of the non-specific infection with the necrotrophic fungus Bc by earlier Psp inoculation was examined. Concentration of reactive oxygen species (ROS), such as superoxide anion (O2 -) and H2O2 and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were determined 6, 12, 24 and 48 h after inoculation. The measurements were done for ROS cytosolic fraction and enzymatic cytosolic or apoplastic fraction. Infection with Psp caused significant increase in ROS levels since the beginning of experiment. Activity of the apoplastic enzymes also increased remarkably at the beginning of experiment in contrast to the cytosolic ones. Cytosolic SOD and guaiacol peroxidase (GPOD) activities achieved the maximum values 48 h after treatment. Additional forms of the examined enzymes after specific Psp infection were identified; however, they were not present after single Bc inoculation. Subsequent Bc infection resulted only in changes of H2O2 and SOD that occurred to be especially important during plant–pathogen interaction. Cultivar Korona of common bean is considered to be resistant to Psp and mobilises its system upon infection with these bacteria. We put forward a hypothesis that the extent of defence reaction was so great that subsequent infection did not trigger significant additional response

Adaptation of the difficulty level in an infant-robot movement contingency study

19th International Workshop of Physical Agents (WAF). Madrid (22-23 Noviembre 2018)ABSTRACT: This paper presents a personalized contingency feedback adaptation system that aims to encourage infants aged 6 to 8 months to gradually increase the peak acceleration of their leg movements. The ultimate challenge is to determine if a socially assistive humanoid robot can guide infant learning using contingent rewards, where the reward threshold is personalized for each infant using a reinforcement learning algorithm. The model learned from the data captured by wearable inertial sensors measuring infant leg movement accelerations in an earlier study. Each infant generated a unique model that determined the behavior of the robot. The presented results were obtained from the distributions of the participants' acceleration peaks and demonstrate that the resulting model is sensitive to the degree of differentiation among the participants; each participant (infant) should have his/her own learned policy.This work was supported by NSF award 1706964 (PI: Smith, Co-PI: Matarić). In addition, this work was developed during an international mobility program at the University of Southern California being also partially funded by the European Union ECHORD++ project (FP7-ICT-601116), the LifeBots project (TIN2015-65686-C5) and THERAPIST project (TIN2012-38079)

Interaction of water unextractable solids with gluten protein: effect on dough properties and gluten quality

Abstract In a previous study, we have shown that water unextractable solids (WUS) interfere with gluten formation and affect the quality of the resulting gluten. In this study we aim to explain how WUS can affect the process of gluten formation. To this end, WUS were modified with NaOH, xylanase, horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). Effects of modified WUS on gluten yield, dough properties, and gluten and glutenin macropolymer (GMP) composition and properties were studied. The results showed that addition of WUS to wheat flour led to a lower gluten yield and gluten starch yield, a higher Rmax and a lower E at Rmax of gluten and a more concentrated and elastic GMP gel. Pretreatment of WUS by NaOH, xylanase, HRP and H2O2 cannot correct its negative effect on gluten yield, but addition of xylanase or free ferulic acid (FA) during gluten separation can remove or prevent the negative effect of WUS on gluten yield. Compared to addition of only WUS, addition of WUS and FA together to wheat flour resulted in a higher gluten yield, a higher E at Rmax of gluten, and a less concentrated and elastic GMP gel. Similar to water extractable pentosans (WEP), FA bound WUS plays a key role in the effect of WUS on gluten yield and properties. It appears that there is a common mechanism regarding the effect of WUS and WEP that the oxidative cross-linking during gluten formation could be prevented by FA addition. The difference between both is that WUS have a higher water binding capacity, which is reflected in a higher Rmax of dough and gluten in the presence of WUS. Author Keywords: Water unextractable solids; Dough properties; Gluten qualit

Young children's exploration of the indoor playroom space in center-based childcare

Exploration plays a key role in the development of children. While exploring, children develop new skills by perceiving and acting upon the possibilities for action that are specified in the environment. This study examined the relations between young children's exploration during free play and the spatial characteristics of the indoor playroom space in childcare centers, using an observation scheme based on Gibson's theory of perception-action affordances. The study was carried out in mixed-age groups, with ages ranging between 11 and 48 months. The results showed that depth of exploration of space was positively related to the use of tables and activity centers, and also to the child's task-orientation as rated by the caregivers. Breadth of exploration revealed a reversed pattern of relations. The findings indicate that studying children's exploration of indoor playroom space as affordances-guided perception-action cycles can contribute to a more comprehensive understanding of the role of spatial attributes in children's exploratory play

Method of enzymatically cross-linking proteins and phenolic polymers

The present invention relates to a method of cross-linking a protein or peptide and a phenolic polymer or oligomer having substituents derived from carboxylic acids containing hydroxyl substituted phenyl groups by means of an enzyme and an oxidizing agent suitable for the enzyme in a solvent, which method comprises reacting a mixture of protein or peptide, oxidizing agent, enzyme and polymer or oligomer in the solvent, wherein the method is controlled such that in the mixture the ratio of target amino groups in the protein or peptide to hydroxyl substituted phenyl groups in the polymer or oligomer is more than equimolar. With the present method predominantly hetero-cross-linking of protein and polymer occurs