Glucose modulates proliferation in root apical meristems via TOR in maize during germination.

The Glucose-Target of Rapamycin (Glc-TOR) pathway has been studied in different biological systems, but scarcely during early seed germination. This work examines its importance for cell proliferation, expression of cell cycle key genes, their protein levels, besides morphology and cellularization of the root apical meristem of maize (Zea mays) embryo axes during germination under the influence of two simple sugars, glucose and sucrose, and a specific inhibitor of TOR activity, AZD 8055. The two sugars promote germination similarly and to an extent, independently of TOR activity. However, the Glc-TOR pathway increases the number of cells committed to proliferation, increasing the expression of a cell cycle gene, ZmCycD4;2, a putative G1/S regulator. Also, Glc-TOR may have influence on the protein stability of another G1/S cyclin, ZmCycD3, but had no influence on ZmCDKA;1 or ZmKRP3 or their proteins. Results suggest that the Glc-TOR pathway participates in the regulation of proliferation through different mechanisms that, in the end, modify the timing of seed germination.

[Is there a risk of adverse health effects from the consumption of fortified foods in Mexico?] / ¿Hay riesgo de efectos adversos por el consumo de nutrimentos a partir de productos alimenticios adicionados en México?

INTRODUCTION: according to the nutriment addition scheme from the current Mexican legislation, there is no data about overdose or adverse effects caused by a nutriment, or any information showing the risk for the population in Mexico. This work is classified as descriptive and observational. AIM: to assess the risk of consuming fortified food products (FFP) in Mexico. METHODS: the study was done in three phases: a) selection of the FFP and acquisition of the information from the nutritional facts label; b) elaboration of six diets according to the socioeconomic status, both in rural and urban areas, based on the ENIGH and ENSANUT surveys; and c) comparison of these diets with regimes containing FFP, calculated for an adult-equivalent (2,828 kcal). RESULTS: the FFP represent 10% of all the products in the market, being milk, corn and wheat flour, and their byproducts the most abundant. The six diets containing FFP were deficient in calcium, ascorbic acid and vitamins D and E. However, vitamins from the B complex were over the recommendation values. In general, any added nutriment was over the tolerable upper intake levels (UL). CONCLUSIONS: we demonstrated that the nutriment concentrations in the FFP do not reach the UL values and are not a risk for the Mexican population; however, they improve the nutritional contribution of the FFP.

INTRODUCCIÓN: en México no existen datos de sobredosis o reacciones adversas causadas por algún nutrimento o dato alguno que indique riesgo a la población de acuerdo al esquema de adición de nutrimentos de la legislación mexicana vigente. Este trabajo se clasifica como descriptivo y observacional. OBJETIVO: valorar el riesgo por consumo de productos alimenticios adicionados (PAA) en México. MÉTODOS: se realizó en tres fases: a) selección de PAA y obtención de la información nutrimental de las etiquetas; b) elaboración de seis dietas de acuerdo al estrato socioeconómico, tanto en el ámbito rural como en el urbano con base a las encuestas ENIGH y ENSANUT; y c) comparación de estas dietas con dietas que incluyen PAA, calculadas para un adulto equivalente (2.828 kcal). RESULTADOS: los PAA representan el 10% del total de productos presentes en el mercado. Los más frecuentes son: leche, harinas de maíz y trigo y sus derivados. Las seis dietas con PAA presentaron deficiencias en calcio, ácido ascórbico, vitamina D y E. Sin embargo, las vitaminas del complejo B superaron la recomendación. En general, ningún nutrimento adicionado se encontró por arriba del nivel de ingestión tolerable superior (UL). CONCLUSIONES: se demostró que las concentraciones de los nutrimentos en los PAA no alcanzan los UL y no representan un riesgo para la población mexicana, sin embargo, mejoran su aporte nutrimental.

¿Hay riesgo de efectos adversos por el consumo de nutrimentos a partir de productos alimenticios adicionados en México? / Is there a risk of adverse health effects from the consumption of fortified foods in Mexico?

Introducción: en México no existen datos de sobredosis o reacciones adversas causadas por algún nutrimento o dato alguno que indique riesgo a la población de acuerdo al esquema de adición de nutrimentos de la legislación mexicana vigente. Este trabajo se clasifica como descriptivo y observacional. Objetivo: valorar el riesgo por consumo de productos alimenticios adicionados (PAA) en México. Métodos: se realizó en tres fases: a) selección de PAA y obtención de la información nutrimental de las etiquetas; b) elaboración de seis dietas de acuerdo al estrato socioeconómico, tanto en el ámbito rural como en el urbano con base a las encuestas ENIGH y ENSANUT; y c) comparación de estas dietas con dietas que incluyen PAA, calculadas para un adulto equivalente (2.828 kcal). Resultados: los PAA representan el 10% del total de productos presentes en el mercado. Los más frecuentes son: leche, harinas de maíz y trigo y sus derivados. Las seis dietas con PAA presentaron deficiencias en calcio, ácido ascórbico, vitamina D y E. Sin embargo, las vitaminas del complejo B superaron la recomendación. En general, ningún nutrimento adicionado se encontró por arriba del nivel de ingestión tolerable superior (UL). Conclusiones: se demostró que las concentraciones de los nutrimentos en los PAA no alcanzan los UL y no representan un riesgo para la población mexicana, sin embargo, mejoran su aporte nutrimental

Introduction: according to the nutriment addition scheme from the current Mexican legislation, there is no data about overdose or adverse effects caused by a nutriment, or any information showing the risk for the population in Mexico. This work is classified as descriptive and observational. Aim: to assess the risk of consuming fortified food products (FFP) in Mexico. Methods: the study was done in three phases: a) selection of the FFP and acquisition of the information from the nutritional facts label; b) elaboration of six diets according to the socioeconomic status, both in rural and urban areas, based on the ENIGH and ENSANUT surveys; and c) comparison of these diets with regimes containing FFP, calculated for an adult-equivalent (2,828 kcal). Results: the FFP represent 10% of all the products in the market, being milk, corn and wheat flour, and their byproducts the most abundant. The six diets containing FFP were deficient in calcium, ascorbic acid and vitamins D and E. However, vitamins from the B complex were over the recommendation values. In general, any added nutriment was over the tolerable upper intake levels (UL). Conclusions: we demonstrated that the nutriment concentrations in the FFP do not reach the UL values and are not a risk for the Mexican population; however, they improve the nutritional contribution of the FFP

Glucose and sucrose differentially modify cell proliferation in maize during germination.

Glucose and sucrose play a dual role: as carbon and energy sources and as signaling molecules. In order to address the impact that sugars may have on maize seeds during germination, embryo axes were incubated with or without either of the two sugars. Expression of key cell cycle markers and protein abundance, cell patterning and de novo DNA synthesis in root meristem zones were analyzed. Embryo axes without added sugars in imbibition medium were unable to grow after 7 days; in sucrose, embryo axes developed seminal and primary roots with numerous root hairs, whereas in glucose axes showed a twisted morphology, no root hair formation but callus-like structures on adventitious and primary seminal roots. More and smaller cells were observed with glucose treatment in root apical meristems. de novo DNA synthesis was stimulated more by glucose than by sucrose. At 24 h of imbibition, expression of ZmCycD2;2a and ZmCycD4;2 was increased by sucrose and reduced by glucose. CDKA1;1 and CDKA2;1 expression was stimulated equally by both sugars. Protein abundance patterns were modified by sugars: ZmCycD2 showed peaks on glucose at 12 and 36 h of imbibition whereas sucrose promoted ZmCycD3 protein accumulation. In presence of glucose ZmCycD3, ZmCycD4 and ZmCycD6 protein abundance was reduced after 24 h. Finally, both sugars stimulated ZmCDKA protein accumulation but at different times. Overall, even though glucose appears to act as a stronger mitogen stimulator, sucrose stimulated the expression of more cell cycle markers during germination. This work provides evidence of a differential response of cell cycle markers to sucrose and glucose during maize germination that may affect the developmental program during plantlet establishment.

[Multivariate model to predict Streptococcus pyogenes tonsillitis]. / Modelo multivariado para predecir amigdaltis estreptócócica.

OBJECTIVE: to develop a multivariate model to predict the Streptococcus pyogenes isolation in patients with acute tonsillitis. METHODS: cross-sectional analytic study on patients with acute tonsillitis without a recent history of antimicrobial consumption. We evaluated 14 signs and 18 symptoms. A pharyngeal culture was realized on 5% sheep blood agar. Group A streptococci was identified by standard methods. STATISTICAL ANALYSIS: sensitivity, specificity, predictive values, chi2, Fisher's exact test, crude and adjusted odds ratio (OR) with 95% CI using dichotomical logistic regression with direct method and Hosmer and Lemeshow-goodness-fit test. RESULTS: there were 213 participants, 37% were males; a mean age of 14.9 years. We isolated Streptococcus pyogenes in 15%, and 84 % of them had received antimicrobials. We identified signs and symptoms associated with Streptococcus pyogenes isolation: painful swallowing (OR=4.45, 95% CI = 1.13-17.53); tonsils with exudates (OR=3.20, 95% CI = 1.22-8.43); smelly breath (OR=2.78, 95% CI = 1.09-7.10); painful neck nodes (OR=2.70, 95% CI = 1.05-6.96). The presence of nasal symptoms was a protective factor (OR=0.25, 95% CI = 0.09-0.71). CONCLUSIONS: the prevalence of Streptococcus pyogenes tonsillitis was similar to other reports. We found signs and symptoms associated to Streptococcus pyogenes isolation that allowed us to elaborate a decision algorithm.