Transglutaminase-mediated modification of ovomucoid: effects on its trypsin inhibitory activity and antigenic properties

Hen egg can cause food hypersensitivity in infants and young children, and ovomucoid is the most allergenic factor among proteins contained in egg white. Since proteinase treatment, a well-recognized strategy in reducing food allergenicity, is ineffective when applied to ovomucoid because of its ability to act as trypsin inhibitor, we investigated the possibility of reducing the ovomucoid antiprotease activity and antigenic properties by covalently modifying its structure. The present paper reports data showing the ability of the Gln115 residue of ovomucoid to act as an acyl donor substrate for the enzyme transglutaminase and, as a consequence, to give rise to a covalent monodansylcadaverine conjugate of the protein in the presence of both enzyme and the diamine dansylated derivative. Moreover, we demonstrated that the obtained structural modification of ovomucoid significantly reduced the capability of the protein to inhibit trypsin activity, also having impact on its anti-ovomucoid serum-binding properties.     

Legacies in Switchgrass Resistance to and Recovery from Drought Suggest That Good Years Can Sustain Plants Through Bad Years

The warm-season perennial switchgrass (Panicum virgatum) is a candidate bioenergy crop. To be successful, switchgrass production must be maintained on low-quality landscapes with minimal inputs while facing future climates that are expected to be more extreme and more variable. We propose that antecedent rainfall constrains how plants respond to drought, as well as subsequently recover from drought. To test this idea, we examined how six switchgrass genotypes responded to a 1-year severe drought and then recovered under normal rainfall in the following year. These plants had previously grown for 3 years under a range of dry to wet rainfall levels in a shallow-soil common garden with no fertilizer. Plants previously exposed to drought produced less biomass, and basal area after the severe drought was relieved compared to previously well-watered plants. In addition, there were legacy effects caused by plant size: plants that were larger pre-drought were more likely to survive the severe drought, and plants that were larger during the severe drought recovered more biomass, basal area, and tillers post-drought. Although genotypes differed somewhat in their responses, the size constraint was consistent across genotypes. These findings suggest that we can establish more drought-resilient switchgrass stands by, for example, planning for initial irrigation or planting during a wet year to allow plants to grow larger prior to experiencing drought. Additional studies are needed to understand whether these rainfall and size legacies persist or are transient.     

Fennel waste-based films suitable for protecting cultivations

Biodegradable, flexible, and moisture-resistant films were obtained by recycling fennel waste and adding to fennel homogenates the bean protein phaseolin that was modified or not modified by the enzyme transglutaminase. All films were analyzed for their morphology, mechanical properties, water vapor permeability, and susceptibility to biodegradation under soil-like conditions. Our experiments showed that transglutaminase treatment of the phaseolin-containing fennel waste homogenates allowed us to obtain films comparable in their mechanical properties and water vapor permeability to the commercial films Ecoflex and Mater-Bi. Furthermore, biodegradability tests demonstrated that the presence of the enzyme in the film-casting sample significantly influences the integrity of such a product that lasts longer than films obtained either with fennel waste alone or with a mixture of fennel waste and phaseolin. These findings indicate the fennel-phaseolin film prepared in the presence of transglutaminase to be a promising candidate for a new environmentally friendly mulching bioplastic.     

Effect of slice thickness on brain magnetic resonance image texture analysis

Background  

The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients.     

Ecoepidemiology,short history and control of Chagas disease in the endemic countries and the new challenge for non-endemic countries

Chagas disease is maintained in nature through the interchange of three cycles: the wild, peridomestic and domestic cycles. The wild cycle, which is enzootic, has existed for millions of years maintained between triatomines and wild mammals. Human infection was only detected in mummies from 4,000-9,000 years ago, before the discovery of the disease by Carlos Chagas in 1909. With the beginning of deforestation in the Americas, two-three centuries ago for the expansion of agriculture and livestock rearing, wild mammals, which had been the food source for triatomines, were removed and new food sources started to appear in peridomestic areas: chicken coops, corrals and pigsties. Some accidental human cases could also have occurred prior to the triatomines in peridomestic areas. Thus, triatomines progressively penetrated households and formed the domestic cycle of Chagas disease. A new epidemiological, economic and social problem has been created through the globalisation of Chagas disease, due to legal and illegal migration of individuals infected by Trypanosoma cruzi or presenting Chagas disease in its varied clinical forms, from endemic countries in Latin America to non-endemic countries in North America, Europe, Asia and Oceania, particularly to the United States of America and Spain. The main objective of the present paper was to present a general view of the interchanges between the wild, peridomestic and domestic cycles of the disease, the development of T. cruzi among triatomine, their domiciliation and control initiatives, the characteristics of the disease in countries in the Americas and the problem of migration to non-endemic countries.     

Information propagation within the Genetic Network of Saccharomyces cerevisiae

Background  

A gene network's capacity to process information, so as to bind past events to future actions, depends on its structure and logic. From previous and new microarray measurements in Saccharomyces cerevisiae following gene deletions and overexpressions, we identify a core gene regulatory network (GRN) of functional interactions between 328 genes and the transfer functions of each gene. Inferred connections are verified by gene enrichment.     

Higher susceptibility to amyloid fibril formation of the recombinant ovine prion protein modified by transglutaminase

Prion proteins are known as the main agents of transmissible spongiform encephalopathies affecting humans as well as animals. A recombinant ovine prion protein was found to be in vitro able to act as an effective substrate for a microbial isoform of transglutaminase, an enzyme catalyzing the formation of isopeptide bonds inside the proteins. We proved that transglutaminase modifies the structure of the prion protein by leading to the formation of three intra-molecular crosslinks and that the crosslinked protein form is more competent in amyloid formation compared to the unmodified one. In addition, the crosslinked prion protein was shown also to be more resistant to proteinase K digestion. Our findings suggest a possible use of transglutaminase in stabilizing the prion protein three-dimensional structure in order to investigate the molecular basis of the conversion of the protein into its pathological form.     

MORPHOLOGICAL,ANATOMICAL, AND MOLECULAR CONSEQUENCES OF GROWTH AND DEVELOPMENT AT LOW TEMPERATURE IN SECALE CEREALE

Growth of winter cereals at low, nonfreezing temperatures is essential for the establishment of a cold-hardy state and subsequent survival of the overwintering plant. In this paper, I describe the consequences of growth and development of Secale cereale L. cv. Puma at cold-hardening temperatures with respect to leaf morphology, anatomy, and biochemistry, and with particular emphasis on their relationship to photosynthetic acclimation. Low temperature-induced structural and functional alterations at the level of ribulose bisphosphate carboxylase-oxygenase and the chloroplast thylakoid membrane are described and related to overall photosynthetic efficiency and capacity for CO₂ utilization. Growth and development at cold-hardening temperatures appear to result in changes in protein conformation and membrane organization, but not in basic composition. It is proposed that developmental temperature imparts a significant effect on the assembly of these multimeric, photosynthetic components, which leads to distinct structural and functional changes.     

Number of rare germline CNVs and <Emphasis Type="Italic">TP53</Emphasis> mutation types

Background

The Li-Fraumeni syndrome (LFS), an inherited rare cancer predisposition syndrome characterized by a variety of early-onset tumors, is caused by different highly penetrant germline mutations in the TP53 gene; each separate mutation has dissimilar functional and phenotypic effects, which partially clarifies the reported heterogeneity between LFS families. Increases in copy number variation (CNV) have been reported in TP53 mutated individuals, and are also postulated to contribute to LFS phenotypic variability. The Brazilian p.R337H TP53 mutation has particular functional and regulatory properties that differ from most other common LFS TP53 mutations, by conferring a strikingly milder phenotype.

Methods

We compared the CNV profiles of controls, and LFS individuals carrying either p.R337H or DNA binding domain (DBD) TP53 mutations by high resolution array-CGH.

Results

Although we did not find any significant difference in the frequency of CNVs between LFS patients and controls, our data indicated an increased proportion of rare CNVs per genome in patients carrying DBD mutations compared to both controls (p=0.0002***) and p.R337H (0.0156*) mutants.

Conclusions

The larger accumulation of rare CNVs in DBD mutants may contribute to the reported anticipation and severity of the syndrome; likewise the fact that p.R337H individuals do not present the same magnitude of rare CNV accumulation may also explain the maintenance of this mutation at relatively high frequency in some populations.

     

Characterization of two heparan sulphate-binding sites in the mycobacterial adhesin Hlp

Background  

The histone-like Hlp protein is emerging as a key component in mycobacterial pathogenesis, being involved in the initial events of host colonization by interacting with laminin and glycosaminoglycans (GAGs). In the present study, nuclear magnetic resonance (NMR) was used to map the binding site(s) of Hlp to heparan sulfate and identify the nature of the amino acid residues directly involved in this interaction.