EFFECTS OF THE ADDITION OF SUGARS ON THE THERMOSTABILITY OF BETANIN FROM Beta vulgaris L.

O impacto da adição de açúcares na estabilidade das betaninas de Beta vulgaris L. (beterraba) durante o tratamento térmico entre 50 e 80°C e pH 5 foi investigado. A degradação das betaninas pura e adicionada de 10% de sacarose e 40% de frutose seguiu modelo de cinética de primeira ordem e conforme aumento da temperatura, houve aumento dos valores da constante de degradação térmica (Kd), redução na meia-vida e nos valores do tempo de redução decimal (D). Termodinamicamente, apresentando valores de variação de entalpia (ΔH) mais altos (entre 99,66 e 99,41 kJ mol-1) que o extrato com a adição de sacarose (entre 85,27 e 85,03 kJ mol-1) e controle (entre 78,85 e 78,61 kJ mol-1), a incorporação de frutose foi mais promissora no aumento da estabilidade do extrato de betaninas. Os valores positivos para a variação da energia livre de Gibbs (ΔG) indicaram que a reação de degradação das betaninas foi não-espontânea e os baixos valores da variação de entropia (ΔS) para o extrato com frutose (entre 0,02 e 0,03 J mol-1K-1) indicaram que o estado do material estava próximo ao seu equilíbrio termodinâmic

Guided play and free play in an enriched environment: impact on motor development

The purpose of this study was to investigate the effects of guided play and free play in an enriched environment intervention programs using motor skill development in kindergarten children. Seventy-one children attending kindergarten classes were assigned to two experimental groups and one control group. Participants performed the Test of Gross Motor Development-2 before and after the intervention period. Results revealed that both boys and girls in the guided play group showed motor skill improvement, whereas no changes were observed in motor development in the boys and girls assigned to the free play in enriched environment group, nor in those in the control group. These findings indicate that the teacher’s role in the guided play intervention was crucial to help preschool children to improve their performance.CIEC – Research Centre on Child Studies, UM (FCT R&D 317

Subdominant/Cryptic CD8 T Cell Epitopes Contribute to Resistance against Experimental Infection with a Human Protozoan Parasite

During adaptive immune response, pathogen-specific CD8+ T cells recognize preferentially a small number of epitopes, a phenomenon known as immunodominance. Its biological implications during natural or vaccine-induced immune responses are still unclear. Earlier, we have shown that during experimental infection, the human intracellular pathogen Trypanosoma cruzi restricts the repertoire of CD8+ T cells generating strong immunodominance. We hypothesized that this phenomenon could be a mechanism used by the parasite to reduce the breath and magnitude of the immune response, favoring parasitism, and thus that artificially broadening the T cell repertoire could favor the host. Here, we confirmed our previous observation by showing that CD8+ T cells of H-2a infected mice recognized a single epitope of an immunodominant antigen of the trans-sialidase super-family. In sharp contrast, CD8+ T cells from mice immunized with recombinant genetic vaccines (plasmid DNA and adenovirus) expressing this same T. cruzi antigen recognized, in addition to the immunodominant epitope, two other subdominant epitopes. This unexpected observation allowed us to test the protective role of the immune response to subdominant epitopes. This was accomplished by genetic vaccination of mice with mutated genes that did not express a functional immunodominant epitope. We found that these mice developed immune responses directed solely to the subdominant/cryptic CD8 T cell epitopes and a significant degree of protective immunity against infection mediated by CD8+ T cells. We concluded that artificially broadening the T cell repertoire contributes to host resistance against infection, a finding that has implications for the host-parasite relationship and vaccine development

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Influence of the complexation with β-cyclodextrin on dexamethasone acetate release from hydrophilic matrices of Hydroxypropylmethylcellulose (HPMC) and Polyethylene oxide (PEO)

O acetato de dexametasona (ADM), um fármaco de escassa solubilidade, foi incorporado em sua forma livre, complexada ou misturada fisicamente com β-ciclodextrina (βCD) em matrizes hidrofílicas de hidroxipropilmetilcelulose (HPMC) ou polioxetileno (PEO) em diferentes graus de viscosidade/peso molecular. A avaliação dos perfis de liberação in vitro indicou que as formulações mostraram-se eficazes na extensão da liberação do ADM, sendo a velocidade de liberação modificada como conseqüência da complexação. A aplicação de modelos matemáticos (zero ordem, Higuchi e Korsmeyer-Peppas) permitiu a caracterização da cinética de liberação, indicando que o método de complexação, polímero e viscosidade/peso molecular influenciaram os mecanismos pelos quais o fármaco foi liberado. Além disso, a equação de Weibull mostrou-se útil na diferenciação dos perfis de liberação de algumas formulações, quando os parâ- metros escala (α) e formato (β) foram avaliadosThe dexamethasone acetate (DMA), a poorly water soluble drug, was incorporated alone, complexed or physically mixed with β-cyclodextrin (βCD), in hydrophilic matrix capsules containing hydroxypropyl methylcellulose (HPMC) or polyethylene oxide (PEO) in different viscosity/molecular weight. The evaluation of in vitro release profiles indicated that the formulations were effective in the extension of DMA release, being the release velocity modified due to complexation. The application of the mathematical models (zero order, Higuchi and Korsmeyer-Peppas) allowed the characterization of the release kinetics, indicating that the complexation method, polymer and viscosity/molecular weight influenced the mechanisms by which drug was released. Nevertheless, Weibull equation revealed to be useful in the differentiation of release profiles of some formulations, when the scale (α) and format (β) parameters were evaluatedColegio de Farmacéuticos de la Provincia de Buenos Aire

Physicochemical Properties and Dissolution Studies of Dexamethasone Acetate-β-Cyclodextrin Inclusion Complexes Produced by Different Methods

Inclusion complexes between dexamethasone acetate (DMA), a poorly water soluble drug, and β-cyclodextrin (βCD) were obtained to improve the solubility and dissolution rate of this drug. Phase-solubility profile indicated that the solubility of DMA was significantly increased in the presence of βCD (33-fold) and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Solid complexes prepared by different methods (kneading, coevaporation, freeze drying) and physical mixture were characterized by differential scanning calorimetry, thermogravimetry, infrared absorption and optical microscopy. Preparation methods influenced the physicochemical properties of the products. The dissolution profiles of solid complexes were determined and compared with those DMA alone and their physical mixture, in three different mediums: simulated gastric fluid (pH 1.2), simulated intestinal fluid (pH 7.4) and distilled water. The dissolution studies showed that in all mediums DMA presented an incomplete dissolution even in four hours. In contrast, the complexes formed presented a higher dissolution rate in simulated gastric fluid (SGF pH 1.2), which indicate that these have different ionization characteristics. According to the results, the freeze–dried and kneaded products exhibited higher dissolution rates than the drug alone, in all the mediums

Isolation and characterization of a stress-inducible Dunaliella salina Lcy-β gene encoding a functional lycopene β-cyclase

The halotolerant green alga Dunaliella salina accumulates large amounts of β-carotene when exposed to various stress conditions. Although several studies concerning accumulation and biotechnological production of β-carotene have been published, the molecular basis and regulation of the genes involved in carotenoid biosynthesis in D. salina are still poorly known. In this paper, we report the isolation and regulation of the lycopene β-cyclase (Lcy-β) gene by abiotic stress. The function of this gene was determined by heterologous genetic complementation in E. coli. Gene expression and physiological analyses revealed that D. salina Lcy-β steady-state transcript and carotenoid levels were up-regulated in response to all stress conditions tested (salt, light and nutrient depletion). The results presented here suggest that nutrient availability is a key factor influencing carotenogenesis as well as carotenoid biosynthesis-related gene expression in D. salina.FCT, European Unio