Classification of activity engagement in individuals with severe physical disabilities using signals of the peripheral nervous system

Communication barriers often result in exclusion of children and youth with disabilities from activities and social settings that are essential to their psychosocial development. In particular, difficulties in describing their experiences of activities and social settings hinder our understanding of the factors that promote inclusion and participation of this group of individuals. To address this specific communication challenge, we examined the feasibility of developing a language-free measure of experience in youth with severe physical disabilities. To do this, we used the activity of the peripheral nervous system to detect patterns of psychological arousal associated with activities requiring different patterns of cognitive/affective and interpersonal involvement (activity engagement). We demonstrated that these signals can differentiate among patterns of arousal associated with these activities with high accuracy (two levels: 81%, three levels: 74%). These results demonstrate the potential for development of a real-time, motor- and language-free measure for describing the experiences of children and youth with disabilities.     

Method to assemble and integrate biochemical pathways into the chloroplast genome of Chlamydomonas reinhardtii

Recombinant protein expression in the chloroplasts of green algae has recently become more routine; however, the heterologous expression of multiple proteins or complete biosynthetic pathways remains a significant challenge. Here, we show that a modified DNA Assembler approach can be used to rapidly assemble multiple‐gene biosynthetic pathways in yeast and then integrate these assembled pathways at a site‐specific location in the chloroplast genome of the microalgal species Chlamydomonas reinhardtii. As a proof of concept, this method was used to successfully integrate and functionally express up to three reporter proteins (AphA6, AadA, and GFP) in the chloroplast of C. reinhardtii. An analysis of the relative gene expression of the engineered strains showed significant differences in the mRNA expression levels of the reporter genes and thus highlights the importance of proper promoter/untranslated region selection when constructing a target pathway. This new method represents a useful genetic tool in the construction and integration of complex biochemical pathways into the chloroplast genome of microalgae and should aid current efforts to engineer algae for biofuels production and other desirable natural products. Biotechnol. Bioeng. 2012; 109: 2896–2903. © 2012 Wiley Periodicals, Inc.     

Role of electrostatic interactions in 2,2,2-trifluoroethanol-induced structural changes and aggregation of alpha-chymotrypsin

It has been recently demonstrated that alpha-chymotrypsin (CT) can be driven toward amyloid aggregation by addition of 2,2,2-trifluoroethanol (TFE), at intermediate concentrations. In the present article, the process of TFE-induced CT aggregation was investigated in more detailed kinetic terms where the effects of medium conditions, such as temperature, presence of kosmotropic and chaotropic salts, pH and chemical modification of lysine residues were examined. Various techniques, including light scattering, fluorescence and circular dichroism spectroscopy, were used to follow and characterize this process. The kinetics of aggregation was found to obey a second-order reaction with respect to protein concentration. The aggregation-prone A-state and aggregation-deficient TFE- or T-state of CT were found to be induced at lower TFE concentrations in the presence of salts. Use of acidic and alkaline conditions and lysine modification also promoted the formation of the T-state. Results presented suggest a role for electrostatic interactions in the aggregation process.     

Hepatic mechanisms of the Walnut antidiabetic effect in mice

The present study was designed to explore the mechanism of action of walnut (the seed of Juglans regia) leaf and ridge on hepatic glucose metabolism in diabetic mice. Experimental diabetes was induced by intravenous administration of streptozotocin (60 mg/kg)and confirmed with an increase of blood glucose, 90–100% of the control, 72 hours later. Isolated extracts from walnut leaf and ridges were administered in a single effective dose of 400 mg/kg orally. Firstly, blood glucose was determined every 1 hour until 5 hours post administration of extracts. In the second experiment, the liver was surgically removed, 2 hours post treatment of diabetic animals with extracts, homogenized and used for measurement of key enzymes of glycogenolysis (glycogen phosphorylase, GP) and gluconeogenesis (phosphoenolpyruvate carboxykinase, PEPCK). Treatment by both leaf and ridge extracts decreased blood glucose and liver PEPCK activity and increased blood insulin and liver GP activity. It is concluded that walnut is able to lower blood glucose through inhibition of hepatic gluconeogenesis and secretion of pancreatic insulin.     

Cellulose nanocrystals from celery stalk as quercetin scaffolds: A novel perspective of human holo-transferrin adsorption and digestion behaviours

In this study, cellulose nanocrystals (CNCs) were synthesized from celery stalks to be used as the platform for quercetin delivery. Additionally, CNCs and CNCs–quercetin were characterized using the results of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and zeta potential, while their interactions with human holo-transferrin (HTF) were also investigated. We examined their interaction under physiological conditions through the exertion of fluorescence, resonance light scattering, synchronized fluorescence spectroscopy, circular dichroism, three-dimensional fluorescence spectroscopy, and fluorescence resonance energy transfer techniques. The data from SEM and TEM exhibited the spherical shape of CNCs and CNCs–quercetin and also, a decrease was detected in the size of quercetin-loaded CNCs from 676 to 473 nm that indicated the intensified water solubility of quercetin. The success of cellulose acid hydrolysis was confirmed based on the XRD results. Apparently, the crystalline index of CNCs–quercetin was reduced by the interaction of CNCs with quercetin, which also resulted in the appearance of functional groups, as shown by FTIR. The interaction of CNCs–quercetin with HTF was also demonstrated by the induced quenching in the intensity of HTF fluorescence emission and Stern–Volmer data represent the occurrence of static quenching. Overall, the effectiveness of CNCs as quercetin vehicles suggests its potential suitability for dietary supplements and pharmaceutical products.     

Elongated oligomers assemble into mammalian PrP amyloid fibrils

In prion diseases, the mammalian prion protein PrP is converted from a monomeric, mainly alpha-helical state into beta-rich amyloid fibrils. To examine the structure of the misfolded state, amyloid fibrils were grown from a beta form of recombinant mouse PrP (residues 91-231). The beta-PrP precursors assembled slowly into amyloid fibrils with an overall helical twist. The fibrils exhibit immunological reactivity similar to that of ex vivo PrP Sc. Using electron microscopy and image processing, we obtained three-dimensional density maps of two forms of PrP fibrils with slightly different twists. They reveal two intertwined protofilaments with a subunit repeat of approximately 60 A. The repeating unit along each protofilament can be accounted for by elongated oligomers of PrP, suggesting a hierarchical assembly mechanism for the fibrils. The structure reveals flexible crossbridges between the two protofilaments, and subunit contacts along the protofilaments that are likely to reflect specific features of the PrP sequence, in addition to the generic, cross-beta amyloid fold.     

Distribution of chigger mites (Acari: Trombiculidae) over hosts,parasitopes, collection localities,and seasons in northern Iran

We studied the distribution of chigger mite species over mammal hosts, attachment sites on the host body, habitats, and seasons in Iran. The study was based on 2155 specimens of 36 chigger species collected from 10 species of Muridae, Cricetidae, and Soricidae across six provinces of northern Iran. A high level of mixed infestation by chiggers was recorded—76% of hosts parasitized by chiggers were infested by more than one (2–8) species. Statistically significant differences in the preference for anterior and posterior parts of the host body were found. Three species—Neotrombicula lubrica, N. delijani, and Cheladonta firdousii—preferred the posterior part of the host body; 12 species were characterized by the occurrence in the anterior part and differed from one another by the frequency of presence in the posterior part. One species, Hirsutiella alpina, was found only in the anterior part of the host body (inside the ears of rodents). The most diverse chigger fauna was on the fringe of Golestan National Park (species richness?=?21, Shannon–Wiener index?=?2.823). The chigger fauna of the high-mountain localities on the Alborz Range was the least diverse (species richness?=?16, Shannon–Wiener index?=?2.439). The seasonal aspect of activity was evident for Neotrombicula elegans, which exposed the autumn–winter period of the occurrence on hosts, and N. vernalis, with the winter-spring peak of abundance.

     

Lutein and cataract: from bench to bedside

Cataract is one of the most important leading causes of blindness in the world. Extensive research showed that oxidative stress may play an important role in the initiation and progression of a cataract and other age-related eye diseases. Extra-generation of reactive oxygen and nitrogen species in the eye tissue has been shown as one of the most important risk factors for cataracts and other age-related eye diseases. With respect to this, it can be hypothesized that dietary antioxidants may be useful in the prevention and/or mitigation of cataract. Lutein is an important xanthophyll which is widely found in different vegetables such as spinach, kale and carrots as well as some other foods such as eggs. Lutein is concentrated in the macula and suppresses the oxidative stress in the eye tissues. A plethora of literature has shown that increased lutein consumption has a close correlation with reduction in the incidence of cataract. Despite this general information, there is a negligible number of review articles considering the beneficial effects of lutein on cataracts and age-related eye diseases. The present review is aimed at discussing the role of oxidative stress in the initiation and progression of a cataract and the possible beneficial effects of lutein in maintaining retinal health and fighting cataract. We also provide a perspective on the chemistry, sources, bioavailability and safety of lutein.