Utilización de dos soportes para la inmovilización de la papaína

Papain was immobilized on activated carbon (AC) and on alumina (AL), with the aim of preparing low cost dietarysupplements, using whey as hydrolysed protein source. The quantifi cation of the non-adsorbed enzyme, using Lowry’smethod was used to determine the immobilization rate. The effect of the contact time and the temperature was tested,and 30 min at 250C was considered the best condition for immobilizing papain in both supports. AC showed muchhigher immobilization rates (from 95% to 99%) than AL (from 4% to 13%). The reusability of papain was evaluated bymeasuring the residual activity of the enzyme after it has been used for up to 20 times. The quantifi cation of exposurerate of phenylalanine by second derivative spectrophotometry was used to determine the enzyme activity. In this case, ALshowed better results than AC, since the activity of papain remained unchanged after 15 and 5 times, respectively.Con la intención de preparar suplementos dietéticos de bajo coste, se inmovilizó papaína en carbón activado (CA) yen alúmina, utilizando suero como fuente de proteínas hidrolizadas. Para determinar el índice de inmovilización secuantifi caron las enzimas no adsorbidas mediante el método de Lowry. Se analizó el efecto del tiempo de contactoy la temperatura, considerándose 30 min. a 25 ºC como la condición óptima para inmovilizar la papaína en ambossoportes. El CA presentó unos índices de inmovilización muy superiores (entre 95% y 99%) a los de la AL (entre4% y 13%). Para evaluar la capacidad de reutilización de la papaína se midió la actividad residual de la enzimadespués de haber sido utilizada hasta 20 veces. Para determinar la actividad de la enzima se cuantifi có el índice deexposición de la fenilalanina mediante espectrofotometría de derivada segunda. En este caso, la AL presentó mejoresresultados que el CA, ya que la actividad de la papaína seguía siendo la misma después de haber sido utilizada 15y 5 veces, respectivamente

Mineral inadequacy of oral diets offered to patients in a Brazilian hospital

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Introduction: While enteral diets for hospitalized patients normally follow nutrient composition guidelines, more than 90% of hospitalized patients receive oral diets with unknown mineral composition. Objective: To evaluate the mineral contents and adequacy of three types of oral diets (regular, blend and soft) and complementary snacks offered to patients of a Brazilian hospital. Methods: The amount of minerals was determined in two non-consecutive days in duplicate samples of breakfast, collation, lunch, snack, dinner, supper and a complementary snack meal. Dietary Reference Intakes (DRIs) were used to determine the adequacy of the daily amounts served to patients. Results and discussion: The regular diet met the RDA (Recommended Dietary Allowances) requirements only for Mn, P and Se, while the blend diet was deficient in Ca, K and Mg, and the soft diet met RDA requirements only for P and Zn. Iron was below the RDA requirement in all diets for women in fertile age, and Na was above the safe limit of intake (UL) in all the diets. The use of complementary snack was effective in meeting RDA requirements for Cu in the regular diet, and Mn and Se in the soft diet, but promoted overconsumption of Na. Conclusions: Evident nutritional imbalances have been detected at a key interphase between nutrition and public health services, but a solution does not appear to be insurmountable. A permanent nutritional evaluation of hospital oral diets should be an integral part of routine health care in order to speed the recovery of the hospitalized patient and dispel eventual risks due to critical mineral imbalances.271288297Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

A cryo-EM grid preparation device for time-resolved structural studies

Structural biology generally provides static snapshots of protein conformations that can provide information on the functional mechanisms of biological systems. Time-resolved structural biology provides a means to visualize, at near-atomic resolution, the dynamic conformational changes that macromolecules undergo as they function. X-ray free-electron-laser technology has provided a powerful tool to study enzyme mechanisms at atomic resolution, typically in the femtosecond to picosecond timeframe. Complementary to this, recent advances in the resolution obtainable by electron microscopy and the broad range of samples that can be studied make it ideally suited to time-resolved approaches in the microsecond to millisecond timeframe to study large loop and domain motions in biomolecules. Here we describe a cryo-EM grid preparation device that permits rapid mixing, voltage-assisted spraying and vitrification of samples. It is shown that the device produces grids of sufficient ice quality to enable data collection from single grids that results in a sub-4 Å reconstruction. Rapid mixing can be achieved by blot-and-spray or mix-and-spray approaches with a delay of ∼10 ms, providing greater temporal resolution than previously reported mix-and-spray approaches

Cochlear Implant: the complexity involved in the decision making process by the family

El objetivo de esta investigación es comprender los significados atribuidos por la familia a las etapas del proceso de la toma de decisiones para el implante coclear en el hijo