Modelling the Effects of Ageing Time of Starch on the Enzymatic Activity of Three Amylolytic Enzymes

The effect of increasing ageing time (t) of starch on the activity of three amylolytic enzymes (Termamyl, San Super, and BAN) was investigated. Although all the enzymatic reactions follow michaelian kinetics, vmax decreased significantly (P < 0.05) and KM increased (although not always significantly) with the increase in t. The conformational changes produced in the starch chains as a consequence of the ageing seemed to affect negatively the diffusivity of the starch to the active site of the enzymes and the release of the reaction products to the medium. A similar effect was observed when the enzymatic reactions were carried out with unaged starches supplemented with different concentrations of gelatine [G]. The inhibition in the amylolytic activities was best mathematically described by using three modified forms of the Michaelis-Menten model, which included a term to consider, respectively, the linear, exponential, and hyperbolic inhibitory effects of t and [G]

Die mycobakteriellen Adenylatcyclasen Rv1625c und Rv0386: Orthodoxe gegenüber unorthodoxer Katalyse

I report on two class III ACs of Mycobacterium tuberculosis which possess very different structural as well as catalytic characteristics: the mammalian-like membrane-anchored Rv1625c and the transcription-factor-attached Rv0386. As a complementary study to published data (Guo et al., 2001), additional point mutations were made which demonstrated the essential role of the six canonical amino acids for catalysis in Rv1625c. The cytosolic mutants of Rv1625c N372A, N372T and D300S were used to investigate dimerization with mammalian AC catalytic units. Rv1625c engineered to contain forskolin binding amino acids cannot be stimulated by the diterpene. The similarities in conformation and mechanisms of catalysis between ACs and GCs was confirmed through the formation of functional chimeras between Mycobacterium Rv1625c and a guanylyl cyclase of Paramecium. The versatility of the class III cyclase homology domains concerning their modular architectures and mechanisms of catalysis was demonstrated with the biochemical characterization of Rv0386. This enzyme has a substrate-defining mechanism distinctly different of that of mammalian ACs. In addition by using ATP as well as GTP as a substrate it is a unique AC isoform unknown so far. Mutational studies of the Rv0386 AC domain proved the essential role that is played by a glutamine and an asparagine instead of the canonical lysine and aspartate for recognition of ATP and GTP as substrates. Diffraction-quality crystals of this AC domain were obtained as a first step to decipher the molecular and structural particularities of its catalytic function. Sequence comparisons identified an ATPase, a HTH DNA-binding and a transcription factor domain in Rv0386. How these domains affect AC activity in a concerted regulatory mechanism remains a pressing question for future studies.Im Rahmen der vorliegenden Arbeit wurden zwei Klasse III ACn aus Mycobacterium tuberculosis mit unterschiedlicher strukturellen und katalytischen Eigenschaften untersucht: die Mammalia-ähnliche Rv1625c und die an einen Transkriptionsfaktor gebundene Rv0386. Als ergänzende Studien zu bereits publizierten Daten (Guo et al., 2001), wurden zur Überprüfung der wesentlichen Rolle der sechs kanonischen Aminosäuren, die bei Mammalia-ACn in der Katalyse beteiligt sind und die in Rv1625c konserviert und auch katalytisch relevant sind, zusätzliche Punktmutationen durchgeführt und getestet. Die Rv1625c Mutanten N372A, N372T und D300S, die einzeln inaktiv sind, wurden für Rekonstitutionsversuchen benutzt wobei die Bildung katalytisch aktiver Homodimere in Rv1625c nachgewiesen wurde. Punktmutationen in Rv1625c, die Forskolin-bindende Aminosäuren in Säugercyclasen betreffen, erfahren dennoch keine Stimulierbarkeit durch das Diterpen. Die Ähnlichkeiten in Struktur und katalytischem Mechanismus zwischen ACn und GCn wurden hier bestätigt, da Chimären zwischen Mycobacterium Rv1625c und einer Guanylatcyclase aus Paramecium aktive katalytische Zentren gebildet haben. Die Vielseitigkeit der Klasse-III Cyclase Homologie Domänen hinsichtlich ihres modularen Aufbaus und ihres katalytischen Mechanismus wurde hier durch die biochemische Charakterisierung von Rv0386 nachgewiesen. Dieses Enzym zeigte einen Mechanismus zur Erkennung des Substrates, der sich von dem der Mammalia-ACn deutlich unterscheidet. Dieser ermöglicht die Erkennung sowohl von ATP als auch GTP als Substrat und ist eine Eigenschaft, die bis jetzt in keiner anderen AC Isoform beobachtet wurde. Mutationen der AC Domäne beweisen die essentielle Rolle, die Glutamin und Asparagine statt dem kanonischen Lysin und Aspartat bei der Erkennung der Substrate ATP und GTP in Rv0386 spielen. Der Erhalt der ersten diffraktionsfähigen Kristalle der AC Domäne innerhalb dieser Arbeit ist ein erster Schritt zur Erkenntnis der Besonderheiten ihrer katalytischen Funktion. Die Suche nach Sequenz Ähnlichkeiten zeigte, dass Rv0386 zusätzlich zu der AC Domäne aus ATPase-, HTH DNA-bindungs- und Transkriptionsfaktor-Domänen besteht. Noch zu beantworten bleibt die Frage, wie die regulatorische Verbindung zwischen der AC Domäne und dem Transkriptionsregulator AC Aktivität und weitere unbekannte Regulationsmechanismen beeinflusst

La Unión Europea como potencia civil: La estrategia de los Laboratorios de Paz en Colombia.

The European Union’s security, in the 21st century, is directly related to the position it would assume in relation to central problems of a globalized world and the role that it would decide to play within the international system. From this point of view, instead of orientating itself merely to the defense of its own interests from a classic view of security matters, it understands that to strengthen the world governance redounds in its own behalf. In this sense, the Peace Laboratories are inscribed within the logic of the European Union’s foreign policy and its relations with Colombia, as they pursue the construction of alternatives options of the citizenship to face the domestic armed conflict, forced displacement, drug-trafficking economy and conditions of social marginality and poverty. As well, this program is coherent with the Euro- pean vision of fighting and preventing conflicts by attacking the structural causes that generate and dynamize them. So, this problem is approached from a global perspective, not limiting the search of solutions to the military environment. Therefore, we conclude that the European Union is consoli- dating an identity in the world scenario as a civilian power.La seguridad de la Unión Europea en el siglo XXI está directamente relacionada con la posición que asuma frente a problemáticas centrales del mundo globalizado y al rol que decida jugar dentro del sistema internacional. Por eso, en vez de orientarse a la defensa exclusiva de sus propios intereses desde una visión clásica de la seguridad, comprende que potenciar la gobernabilidad mundial redunda en sus propios intereses. De modo que los Laboratorios de Paz se inscriben dentro de la lógica de la política exterior de la Unión Europea en el marco de sus relaciones con Colombia, en el sentido que son una búsqueda para la construcción de opciones alternativas de la ciudadanía para enfrentar el conflicto armado interno, el desplazamiento forzado, la economía del narcotráfico y las condiciones sociales de marginalidad y pobreza. Igualmente, este programa es coherente con la visión europea de combatir y prevenir el conflicto, atacando las causas estructurales que lo generan y dinamizan. De esta forma, se aborda dicha problemática a partir de una mirada global, para no limitar únicamente la búsqueda de soluciones en el ámbito militar. Así, pues, la Unión Europea va consolidando una identidad en el escenario mundial, que la empiezan a mostrar ante el mundo como una potencia civil

Biological extraction of bromelain from pineapple byproducts

[Excerpt] Isolation and purification of valuable compounds are very important processes to valorize agro-food byproducts. Currently, protein extraction and development of environmentally friendly technologies are industrially relevant topics [1]. Among the extracted proteins from byproducts proteases are a relevant group for industrial applications. These enzymes are a class of hydrolytic enzymes capable of cleaving the peptide bonds of proteins chains and are essential in physiological processes [2]. (...

Pineapple by-products integrated valorisation towards functional foods

info:eu-repo/semantics/publishedVersio

Prescription errors in a primary care university unit: urgency of pharmaceutical care in Mexico

O objetivo deste trabalho foi avaliar a racionalidade das prescrições como também os erros mais comuns nas prescrições emitidas pelo Centro de Saúde de uma Universidade no México. Foi realizado um estudo retrospectivo de utilização de medicamentos que requeria prescrição médica. 370 expedientes médicos foram aleatoriamente selecionados e revisados, obtendo uma mostra estatísticamente representativa do total de consultas médicas realizadas no período de um ano. A validade da prescrição médica foi feita utilizando as seguintes variáveis: indicação, doses recomendada, via de administração, contra-indicações, interações, duplicação de medicamentos, medicamentos desnecessários ou faltantes. As prescrições médicas foram classificadas como: apropriada (se não foram encontrados erros nas prescrições) ou inapropriada (se foram encontradas ao menos um erro na prescrição). A razão risco-beneficio foi calculada para cada prescrição médica. O estudo revelou alta incidência de prescrições inapropriadas no Centro de Saúde da Universidade do México (58%), causada pelos erros nas doses recomendadas e na seleção do medicamento relacionado com a necessidade do paciente. Como resultado da análise chi2 , foi encontrado que as variáveis fármaco-terapêuticas escolhidas neste estudo para avaliar a prescrição médica, foram determinantes para classificar as prescrições como apropriadas. Nimesulide, ciprofloxacin, ranitidine, ketorolac e paracetamol representaram o maior número de medicamentos prescritos assim como a maior causa de erros encontradas nas prescrições. É importante que um farmacêutico valide os medicamentos prescritos no Centro de Saúde. Este estudo justifica o papel que os farmacêuticos mexicanos deveriam desempenhar para evitar erros na prescrição, como parte importante da equipe médica, assim como a urgência de implementar os cuidados farmacêuticos em todos os estabelecimentos dos Centros de Saúde no México.The purpose of this study was to assess prescription rationality and most common prescription errors at the primary care clinic of a Mexican university.A retrospective drug utilization review of indication-prescription type was carried out. A random sample of 370 medical records of patients assisted over a year period, were reviewed. Prescription appropriateness was evaluated according to the variables: indication, dosage regimen, administration route, contraindications, interactions, medication duplicity, unnecessary or missing medications. Prescriptions were rated as appropriate (no prescription errors found) or inappropriate (at least one prescription error found). The benefit-risk ratio was calculated for each prescription. This study revealed a 58% of inappropriate prescriptions in the Mexican primary care university clinic, mostly due to errors on dosage regimen and innapropiate drug selection. As a result of chi2 analysis, it was found that the pharmacotherapeutic variables chosen for the prescription assessment in this study, were determinant in prescription appropriateness rating. Nimesulide, ciprofloxacin, ranitidine, ketorolac and paracetamol were the most prescribed drugs as well as the most common cause of errors found. The prescription error rate revealed by this study addresses the need for strategies to improve prescription's quality. Introducing pharmacists as a key part of health care team is a mean proposed to prevent medication errors and to solve the urgency of pharmaceutical care implementation in all primary care facilities in Mexico

Effects of feeding of two potentially probiotic preparations from lactic acid bacteria on the performance and faecal microflora of broiler chickens

The aim of this study was to evaluate the potential of two probiotic preparations, containing live lactic acid bacteria (Lactococcus lactis CECT 539 and Lactobacillus casei CECT 4043) and their products of fermentation (organic acids and bacteriocins), as a replacement for antibiotics in stimulating health and growth of broiler chickens. The effects of the supplementation of both preparations (with proven probiotic effect in weaned piglets) and an antibiotic (avilamycin) on body weight gain (BWG), feed intake (FI), feed consumption efficiency (FCE), relative intestinal weight, and intestinal microbiota counts were studied in 1- day posthatch chickens. The experiments were conducted with medium-growth Sasso X44 chickens housed in cages and with nutritional stressed Ross 308 broiler distributed in pens. Consumption of the different diets did not affect significantly the final coliform counts in Sasso X44 chickens. However, counts of lactic acid bacteria and mesophilic microorganisms were higher in the animals receiving the two probiotic preparations (P < 0.05). In the second experiment, although no differences in BWG were observed between treatments, Ross 308 broilers receiving the probiotic Lactobacillus preparation exhibited the lowest FCE values and were considered the most efficient at converting feed into live weight.Instituto Nacional de Investigación y Tecnología Agraria | Ref. CAL01-045-C2-

Modelling the biphasic growth and product formation by Enterococcus faecium CECT 410 in realkalized fed-batch fermentations in whey

The influence of initial pH on growth and nutrient (total sugars, nitrogen, and phosphorous) consumption by Enterococcus faecium CECT 410 was studied during batch cultures in whey. With these data, two realkalized fed-batch fermentations were developed using different feeding substrates. The shift from homolactic to mixed acid fermentation, the biphasic kinetics observed for cell growth and nitrogen consumption and the increase in the concentrations of biomass and products (lactic acid, acetic acid, ethanol, and butane-2,3-diol) were the most noteworthy observations of these cultures. Modelling the fed-batch growth of Ent. faecium with the Logistic and bi-Logistic models was not satisfactory. However, biomass production was best mathematically described with the use of a double Monod model, which was expressed in terms of biomass, product accumulation, and nitrogen utilization. Product formation was successfully modelled with a modified form of the Luedeking and Piret model developed in this study.Instituto Nacional de Investigación y Tecnología Agraria | Ref. CAL01-045-C2-2Ministerio de Educación y Ciencia | Ref. MAT2005-05393-C03-03Ministerio de Educación y Ciencia | Ref. MAT2006-11662- C03-0