SummaryTransgenic plants are attractive biological systems for the large-scale production of pharmaceutical proteins. In particular, seeds offer special advantages, such as ease of handling and long-term stable storage. Nevertheless, most of the studies of the expression of antibodies in plants have been performed in leaves. We report the expression of a In addition, we demonstrate that a plant-made antibody with triantennary highmannose-type N -glycans has similar Fab functionality to its counterpart with biantennary complex N -glycans, but the former antibody interacts with protein A in a stronger manner and is more immunogenic than the latter. Such differences could be related to a variable immunoglobulin G (IgG)-Fc folding that would depend on the size of the N -glycan.

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Soy protein isolates exhibit heterogeneous protein subunit compositions; their structural and functional properties are determined by the processing conditions. Drastic thermal conditions at pH 7 and 9 result in protein denaturation and polymerization, as evidenced by increased water retention capacity and lower solubility, surface hydrophobicity, and a higher level of AB-11S aggregates. Treatments of glycinin with urea and Na2SC>3 at pH 7 incorporated 20% of sulfonate groups, resulted in no solubility losses of 11S protein A and B polypeptides, but increased their surface hydrophobicity. The increase of 7S fraction leads to an increase of aliphatic hydrophobicity. Thermal treatments at pH 7 and lower protein content lead to high solubility and high surface hydrophobicity isolates. 7S globulin was completely denatured, while 11S denaturation depended on the treatment conditions; different proportions of AB-11S, /?-7S, and B-11S aggregates were formed. Thermal treatments at pH 9 favored dissociation and denaturation of AB-11S protein.

Background: Cow’s milk allergy (CMA) is an important problem worldwide and the development of an in vivo system to study new immunotherapeutic strategies is of interest. Intolerance to soybean formula has been described in CMA patients, but it is not fully understood. In this work, we used a food allergy model in BALB/c mice to study the cross-reactivity between cow’s milk protein (CMP) and soy proteins (SP). Methods: Mice were orally sensitized with cholera toxin and CMP, and then challenged with CMP or SP to induce allergy. Elicited symptoms, plasma histamine, humoral and cellular immune response were analyzed. Th1- and Th2-associated cytokines and transcription factors were assessed at mucosal sites and in splenocytes. Cutaneous tests were also performed. Results: We found that the immediate symptoms elicited in CMP-sensitized mice orally challenged with SP were consistent with a plasma histamine increase. The serum levels of CMP-specific IgE and IgG1 antibodies were increased. These antibodies also recognized soy proteins. Splenocytes and mesenteric lymph node cells incubated with CMP or SP secreted IL-5 and IL-13. mRNA expression of Th2-associated genes (IL-5, IL-13, and GATA-3) was upregulated in mucosal samples. In addition, sensitized animals exhibited positive cutaneous tests after the injection of CMP or SP. Conclusions: We demonstrate that CMP-sensitized mice, without previous exposure to soy proteins, elicited hypersensitivity signs immediately after the oral administration of SP, suggesting that the immunochemical cross-reactivity might be clinically relevant. This model may provide an approach to further characterize cross-allergenicity phenomena and develop new immunotherapeutic treatments for allergic patients.

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Increasing the applications of industrial byproducts is of great interest. Therefore, in the present study, sunflower oil cake from a local oil manufacturing company was used to obtain soluble protein concentrates and isolates with different content of phenolic compounds. All the extraction procedures evaluated resulted in concentrates and isolates with water solubility higher than 75% but with different chemical composition, color and physicochemical properties (i.e. surface hydrophobicity, thermal stability, and polypeptide composition). Since no extraction process led to a complete extraction of phenolic compounds, all the products exhibited antioxidant activity, which depended on the concentration of such compounds. Phenolic compounds give a dark color to sunflower protein concentrates and isolates; nevertheless their final color tone was more dependent on the conditions used in the preparation process than on the amount of phenolic compounds in the product. The results demonstrate the value of sunflower industrial oil cake as a source of proteins with high water solubility, good physicochemical properties and antioxidant activity.

Helianthinin, the main storage protein of sunflowers, has low water solubility and does not form a gel when heated; this behavior is different from other 11S globulins and limits its food applications. To understand this particular behavior, changes on helianthinin association-dissociation state induced by modifications in pH and ionic strength were analyzed. The influence of these different medium conditions on its thermal stability and tendency to form aggregates was also studied. Helianthinin behavior at different pH values and ionic strengths is similar to other 11S globulins except that it remains in a trimeric form at pH 11. Helianthinin thermal stability is higher than other 11S globulins but is lower than oat 11S globulin. Alkaline pH produces a 10 degrees C decrease of its denaturation temperature and also of the cooperativity of denaturation process, but it does not affect the denaturation activation energy. The decrease in thermal stability with the pH increase is also manifested by its tendency to form aggregates by SH/SS interchange reactions. When thermal treatments at alkaline pH are performed, all helianthinin subunits form aggregates, characterized by a higher proportion of beta-polypeptides than alpha-polypeptides, which is an indication that aggregation is accompanied by dissociation. Treatments at 80 degrees C are sufficient to induce aggregation but not to produce denaturation, and in these conditions hexameric forms remain after the treatment.

RF2a is a bZIP transcription factor that regulates expression of the promoter of rice tungro bacilliform badnavirus. RF2a is predicted to include three domains that contribute to its function. The results of transient assays with mutants of RF2a from which one or more domains were removed demonstrated that the acidic domain was essential for the activation of gene expression, although the proline-rich and glutamine-rich domains each played a role in this function. Studies using fusion proteins of different functional domains of RF2a with the 2C7 synthetic zinc finger DNA-binding domain showed that the acidic region is a relatively strong activation domain, the function of which is dependent on the context in which the domain is placed. Data from transgenic plants further supported the conclusion that the acidic domain was important for maintaining the biological function of RF2a. The severe stunting symptoms of rice tungro disease are caused by infection of rice tungro bacilliform virus (RTBV), 1 a double-stranded DNA badnavirus. Understanding the transcriptional regulation of RTBV is an important factor to elucidate the basis of the disease. RTBV carries a single, vascular tissue-specific promoter with several defined DNA cis-elements (1-4). Box II, one of the DNA cis-elements in the promoter, is essential for phloem-specific expression of the promoter (3, 4).A bZIP type rice host transcription factor, RF2a, was identified by its interaction with Box II (5). Furthermore, overexpression of RF2a in transgenic plants is sufficient to activate expression of RTBV promoter in other than vascular tissues (6).Temporal and spatial regulation of gene expression relies largely on the function of gene-specific transcription factors and is achieved by the activity of multiple proteins that bind to regulatory elements and with other proteins to alter basal rates of transcription initiation and/or elongation (7-9). A typical gene-specific eukaryotic transcription factor includes a DNAbinding domain and one or more domains that influence the activation or repression of transcription through interactions with general transcription factors, co-factors, chromatin remodeling complexes, and components of RNA polymerase II holoenzyme, among others (7, 10 -13). Transacting domains are often characterized as having a high content of specific amino acids, including domains rich in the acidic amino acids, proline or glutamine (14 -16). Acidic domains have been reported to possess activation functions that include interactions with TATA-binding proteins (TBP) (13, 17), TBP-associated factors (TAFs) (18), TFIIA (19), TFIIB (20, 21), other general transcription complexes (13,22), and co-factors (12). Proline-rich and glutamine-rich domains typically act through interactions with TBP, TAFs, and other co-factors (14). Although proline-rich and glutamine-rich domains act as activation domains in most of the cases, they can also function as repression domains (23,24). RF2a contains three putative transacting domains, namely proline-rich and ac...