Stabilization of betalains by encapsulation-a review.

Betalains are pigments that have properties that benefit health, such as antioxidant, anticancer, and antimicrobial activity, and they also possess a high ability to provide color. However, these pigments, although used as colorants in certain foods, have not been able to be potentialized to diverse areas such as pharmacology, due to their instability to physicochemical factors such as high temperature, pH changes and high water activity. For this reason, different stabilization methods have been reported. The method that has presented best results for diversifying the use of betalains has been encapsulation. Encapsulation is a method of entrapment where the objective is to protect a compound utilizing more stable matrices from encapsulation technologies. This method has been employed to provide greater stability to betalains, using different matrices and encapsulation technologies. However, a review does not exist, to our knowledge, which analyzes the effect of matrices and encapsulation technologies on betalains stabilization. Therefore, the objective of this review article was to evaluate the different matrices and encapsulation techniques that have been employed to stabilize betalains, in order to arrive at specific conclusions concerning the effect of encapsulation on their stabilization and to propose new techniques and matrices that could promote their stabilization.

Functional diversity of phytochrome family in the control of light and gibberellin-mediated germination in Arabidopsis.

In several species, seed germination is regulated by light in a way that restricts seedling emergence to the environmental conditions that are likely to be favourable for the success of the new individual, and therefore, this behaviour is recognized to have adaptive value. The phytochromes are one of the most relevant photoreceptors involved in light perception by plants. We explored the redundancy and diversity functions of the phytochrome family in the control of seed responsiveness to light and gibberellins (GA) by using a set of phytochrome mutants of Arabidopsis. Our data show that, in addition to the well-known role of phyB in the promotion of germination in response to high red to far-red ratios (R/FR), phyE and phyD stimulate germination at very low R/FR ratios, probably by promoting the action of phyA. Further, we show that phyC regulates negatively the seed responsiveness to light, unravelling unexpected functions for phyC in seed germination. Finally, we find that seed responsiveness to GA is mainly controlled by phyB, with phyC, phyD and phyE having relevant roles when acting in a phyB-deficient background. Our results indicate that phytochromes have multiple and complex roles during germination depending on the active photoreceptor background.

Evaluation of immune responses raised against Tc13 antigens of Trypanosoma cruzi in the outcome of murine experimental infection.

We have previously reported that genetic immunization with Tc13Tul antigen of Trypanosoma cruzi, the aetiological agent of Chagas' disease, triggers harmful effects and non-protective immune responses. In order to confirm the role of Tc13 antigens during T. cruzi infection, herein we studied the humoral and cellular immune responses to the Tc13Tul molecule and its EPKSA C-terminal portion in BALB/c T. cruzi-infected mice or mice immunized with recombinant Tc13Tul. Analysis of the antibody response showed that B-cell epitopes that stimulate a sustained IgM production along the infection and high levels of IgG in the acute phase are mainly located at the Tc13 N- and C-terminal domains, respectively. DTH assays showed that T-cell epitopes are mainly at the Tc13 N-terminal segment and that they do not elicit an efficient memory response. Recombinant Tc13Tul did not induce IFN-gamma secretion in either infected or immunized mice. However, a putative CD8+Tc13Tul-derived peptide was found to elicit IFN-gamma production in chronically infected animals. Immunization with recombinant Tc13Tul did not induce pathology in tissues and neither did it protect against the infection. Our results show that in the outcome of T. cruzi infection the Tc13 family protein mainly triggers non-protective immune responses.

Thermoluminescence response of new KCl(X)Br(1-X):EuCl3 sintered phosphors exposed to beta and gamma radiation.

Alkali halides crystals have been the subject of intense research for an understanding of their radiation-induced defects and luminescence properties. They exhibit noteworthy thermoluminescence (TL) properties when exposed to ionising radiation. Currently, these materials are grown employing expensive and rather complicated techniques. In this work, the results on the TL properties of new alkali halides phosphors fabricated by a simple and inexpensive procedure are presented. The samples were made by mixing KCl, KBr and EuCl3 salts, and compressing them at a pressure of 3.2 x 10(7) Pa during 3 min, followed by sintering at 700 degrees C during 24 h under air atmosphere. The dosimetric response of the samples showed an increase with radiation dose in the 1.5-20.0 Gy dose range for beta and gamma radiation. The TL glow curves in sintered samples presented significant differences in their peak structures compared with monocrystalline samples, indicating that the nature of the trapping states and the recombination mechanisms may be different.