Photosynthetic metabolism and antioxidant in Ormosia arborea are modulated by abscisic acid under water deficit? / Metabolismo fotossintético e antioxidante em mudas de Ormosia arborea são modulados pelo ácido abscísico sob deficit hídrico?

The aim of this research was to evaluate the effect of abscisic acid (ABA) on gas exchange and the activity of antioxidant enzymes of Ormosia arborea (Vell.) Harms seedlings under water deficit and its influence on the recovery potential of the seedlings. The experiment was conducted using four treatments, being daily irrigation or water restriction without and with 10 μM ABA. Seedlings under water deficit + ABA showed greater adjustment to drought, and when re-irrigated, they restored photosynthetic metabolism and water potential. ABA minimizes the reduction in the photosynthetic metabolism and water potential of the leaf, however, it does not increase the antioxidant activity of the O. arborea seedlings under water deficit. These results suggest that this species exhibits plasticity, which enables it to survive also in environments subjected to temporary water deficit regardless of the supplementation of ABA. We suggest that other doses of ABA be researched to expand the beneficial effect of ABA on this species.

O objetivo deste trabalho foi avaliar o efeito do ácido abscísico (ABA) nas trocas gasosas e na atividade de enzimas antioxidantes de mudas de Ormosia arborea (Vell.) Harms sob deficiência hídrica e sua influência no potencial de recuperação das mudas. O experimento foi conduzido com quatro tratamentos, sendo eles irrigação diária ou restrição hídrica sem e com 10 μM ABA. As mudas sob déficit hídrico + ABA apresentaram maior ajuste à seca e ao serem re-irrigadas restabeleceram o metabolismo fotossintético e o potencial hídrico. O ABA minimizou a redução do metabolismo fotossintético e do potencial da água na folha, porém, não aumentou a atividade antioxidante de mudas de O. arborea sob déficit hídrico. Esses resultados sugerem que esta espécie apresenta plasticidade fisiológica, o que lhe permite sobreviver em ambientes sujeitos a déficit hídrico temporário, independente da suplementação de ABA. Sugerimos que outras doses de ABA sejam avaliadas para ampliar os efeitos benéficos do ABA sobre esta espécie.

Recomendaciones para el inicio de la terapia de reemplazo enzimático en pacientes con Enfermedad de Fabry clásica en Latinoamérica / Guidelines to start enzyme replacement therapy in classic Fabry Disease patients in Latin America

INTRODUCCIÓN: La Enfermedad de Fabry es una entidad rara hereditaria ligada al cromosoma X, debida a la deficiencia o ausencia de la enzima α-galactosidasa A. OBJETIVO: Presentar la primera recomendación para el inicio oportuno de la terapia de reemplazo enzimático en la variante clásica de la enfermedad, en base al conocimiento y experiencia en el manejo de estos pacientes por un grupo de profesionales expertos en el tema pertenecientes a diez países de Latinoamérica: Argentina, Brasil, Colombia, Costa Rica, Chile, Ecuador, México, Perú, Uruguay y Venezuela. MATERIAL Y MÉTODOS: El coordinador del proyecto diseñó un documento fuente, basado en los criterios de inicio del tratamiento establecidos en las distintas guías internacionales publicadas a la fecha. Posteriormente, se distribuyó la encuesta a todos los participantes para su evaluación. RESULTADOS: Cincuenta expertos respondieron la encuesta online, siendo los criterios divididos en 5 secciones por especialidad, logrando un consenso entre todos ellos. Discusión: Debido a la creciente evidencia sobre la mejor respuesta y pronóstico asociada a un inicio de tratamiento precoz, se definieron los criterios que pueden llevar a una temprana indicación del tratamiento. CONCLUSIÓN: Entendemos que uno de los méritos de esta recomendación fue la inclusión de expertos pertenecientes a 10 países latinoamericanos. Sin embargo, como toda recomendación en una enfermedad multisistémica en plena descripción de nuevos mecanismos fisiopatológicos y complicaciones asociadas quedan manifestaciones no incluidas dentro de los criterios, lo que obliga a la constante necesidad de revisar estas recomendaciones, para poder incluir los cambios a medida que vayan ocurriendo en próximos reportes

INTRODUCTION: Fabry disease is a rare inherited X-linked disorder resulting from the absence or deficient activity of the α-galactosidase A enzyme. OBJECTIVE: To provide the first guideline on the best time to start enzyme replacement therapy to treat classic Fabry disease, based on the knowledge and experience of experts from ten Latin American countries: Argentina, Brazil, Colombia, Costa Rica, Chile, Ecuador, Mexico, Peru, Uruguay and Venezuela. METHODS: The project coordinator designed a survey based on the criteria for starting the treatment which are established in different international guidelines published to date. This document was later sent to all the participants for its evaluation. RESULTS: Fifty experts responded to the survey, whose criteria was divided into 5 sections according to specialty, and they arrived at a consensus. Discussion: The criteria for an early treatment were defined given the growing evidence of a better response and prognosis associated with it. CONCLUSION: We believe that the importance of this guideline relies on the participation of experts from ten Latin American countries. However, as it deals with a systemic disease whose physiopathological mechanisms and complications are still being described, some manifestations have not been included in the criteria, making it necessary to revise this guideline in order to report any changes that may arise in the future

Effect of inactivation and reactivation conditions on activity recovery of enzyme catalysts

Enzymes are labile catalysts with reduced half-life time that can be however improved by immobilization and, furthermore, already inactivated catalyst can be recovered totally or partially, therefore allowing the large scale application of enzymes as process catalysts. In recent years a few studies about reactivation of enzyme catalysts have been published as a strategy to prolong the catalyst lifetime. Reported results are very good, making this strategy an interesting tool to be applied to industrial process. These studies have been focused in the evaluation of different variables that may have a positive impact both in the rate and level of activity recovery, being then critical variables for conducting the reactivation process at productive scale. The present work summarizes the studies done about reactivation strategies considering different variables: type of immobilization, enzyme-support interaction, level of catalyst inactivation prior to reactivation, temperature and presence of modulators.

Characterization of a novel lipase from Bacillus sp. isolated from tannery wastes

Kinetics of a lipase isolated from Bacillus sp. was studied. The enzyme showed maximum activity at pH 9 and temperature 60ºC. The Michaelis constant (K M 0.31 µM) obtained from three different plots i.e., Lineweaver-Burk, Hanes-Wolf and Hofstee, was found to be lower than already reported lipases that confirmed higher affinity of the enzyme for its substrate p-NPL (p-nitrophenyl laurate). Vmax of the enzyme was found to be 7.6 µM/mL/min. Energy of activation calculated from Arrhenius plot was found to be 20.607 kJmol-1. Activation enthalpy (ΔH*) had negative trend and the value for the hydrolysis of p-NPL by the enzyme at optimum temperature was -2.748 kJmol-1 . Activation entropy (ΔS*) and free energy of activation (ΔG*) of the enzyme were found to be 1.468 Jmol-1K-1 and -3.237 kJmol-1, respectively at optimum temperature. Low value of Q10 (0.04788) shows high catalytic activity of the enzyme. Mn2+, Fe2+ and Mg2+ enhanced the lipase activity whereas Cu2+, Na+ and Co2+ inhibited the enzyme activity. However, the enzyme activity was not affected significantly by K+ ions. EDTA and SDS also significantly inhibited the lipase activity. Activity of the enzyme was increased in n-hexane while decreased with increase in concentration of acetone, chloroform, ethanol and isopropanol.

Xylanase and cellulase activities during anaerobic decomposition of three aquatic acrophytes

Enzymatic activity during decomposition is extremely important to hydrolyze molecules that are assimilated by microorganisms. During aquatic macrophytes decomposition, enzymes act mainly in the breakdown of lignocellulolytic matrix fibers (i.e. cellulose, hemicellulose and lignin) that encompass the refractory fraction from organic matter. Considering the importance of enzymatic activities role in decomposition processes, this study aimed to describe the temporal changes of xylanase and cellulose activities during anaerobic decomposition of Ricciocarpus natans (freely-floating), Oxycaryum cubense (emergent) and Cabomba furcata (submersed). The aquatic macrophytes were collected in Óleo Lagoon, Luiz Antonio, São Paulo, Brazil and bioassays were accomplished. Decomposition chambers from each species (n = 10) were set up with dried macrophyte fragments and filtered Óleo Lagoon water. The chambers were incubated at 22.5ºC, in the dark and under anaerobic conditions. Enzymatic activities and remaining organic matter were measured periodically during 90 days. The temporal variation of enzymes showed that C. furcata presented the highest decay and the highest maximum enzyme production. Xylanase production was higher than cellulase production for the decomposition of the three aquatic macrophytes species.

Chromobacterium sp. from the tropics: detection and diversity of phytase activity

Phytases are a group of enzymes that catalyze phytic acid hydrolysis with release of phosphorus (P). The ability of Chromobacterium sp. to produce phytase was detected in 115 out of 118 candidate bacteria isolated from different Brazilian biomas. This is the first report revealing the genus Chromobacterium as phytase producer.

Zygomycetes from herbivore dung in the ecological reserve of Dois Irmãos, Northeast Brazil

Thirty-eight taxa of Zygomycetes distributed in 15 genera were recorded from tapir (Tapirus terrestris), camel (Camelus bactrianus), horse (Equus caballus), deer (Cervus elaphus), agouti (Dasyprocta aguti), donkey (Equus asinus), llama (Llama glama) and waterbuck (Kobus ellipsiprymnus) dung collected at the Reserva Ecológica de Dois Irmãos located in Recife, State of Pernambuco, Northeast Brazil. The samples were collected on a monthly basis from June 2005 to May 2006, taken to the laboratory and incubated in moist chambers. Higher number of taxa was observed in the excrements of tapir, followed by deer and donkey. The highest number of species was detected for Mucor, followed by Pilobolus. Statistical analyses showed significant differences in richness of Zygomycetes taxa between the herbivore dung types. Differences of species composition, however, were weak. Seasonality influenced the Zygomycetes species composition but not its richness. Variations in taxa composition between ruminants and non-ruminants dung were non significant.

Characterization and comparison of Serratia marcescens isolated from edible cactus and from silkworm for virulence potential and chitosan susceptibility

Representative strains of Serratia marcescens from an edible cactus plant and silkworms were characterized and a comparison based on their cellular fatty acid composition, 16S rRNA and groE gene sequence analysis as well as silkworm virulence and chitosan susceptibility was carried out. Results from this study indicate that there are no significant differences between the phenotypic and molecular characterization, virulence and chitosan susceptibility of the S. marcescens strains from the cactus plant and silkworms. Silkworms inoculated with S. marcescens from either plant or silkworm resulted in nearly 100 percent mortality. Chitosan solution exhibited strong antibacterial activity against S. marcescens. This activity increased with the increase of chitosan concentration and incubation time regardless of the strain source. Also, the results indicate that the plant associated S. marcescens maybe plays a possible role in the contamination of humans and animals, in particular silkworms, while chitosan showed a potential to control the contamination caused by S. marcescens.

Isozyme characterization of Capsicum accessions from the Amazonian Colombian collection / Caracterización por isoenzimas de accesiones de Capsicum pertenecientes a la colección amazónica colombiana

Two hundred and sixty-one accessions of the genus Capsicum were obtained from the Colombian Amazonian germplasm bank at Amazonian Institute of Scientific Research (Sinchi) and were evaluated with five polymorphic enzymatic systems, including esterase (EST), peroxidase (PRX), 6-phosphogluconatedehydrogenase (6-PGDH), aspartate amino transferase (GOT), and malic enzyme (ME). Using a cluster analysis (UPGMA) the genetic variability of these accessions were characterized. Grouping of the species C. baccatum and C. pubescens were observed, while the species C. annuum, C. chinense and C. frutescens did not group independently, a result that has been previously reported in isoenzyme analyses of this genus. Several accessions were deemed of particular interest for future ecological and evolutive studies.

Doscientas sesenta y una accesiones del género Capsicum del banco de germoplasma del Instituto Amazónico de Investigaciones Científicas (Sinchi) se evaluaron a través de cinco sistemas enzimáticos polimórficos: esterasa (EST), peroxidasa (PRX), 6-fosfogluconato deshidrogenasa (6-PGDH), aspartato amino transferasa(GOT) y enzima málica (ME). Se utilizó un análisis de agrupamiento (Upgma) con el fin de determinar la variabilidad genética. Se observó un agrupamiento de las especies C. baccatum y C. pubescens, mientras que las especies C. annuum, C. chinense y C. frutescens no mostraron un agrupamiento independiente, lo cual ya ha sido reportado en estudios por isoenzimas para el género. Varias accesiones mostraron característicasparticulares para estudios ecológicos y evolutivos.

UDP-galactose 4-epimerase from Escherichia coli: equilibrium unfolding studies.

UDP-galactose 4-epimerase from Escherichia coli is a homodimer of 39 kDa subunit with non-covalently bound NAD acting as cofactor. The enzyme can be reversibly reactivated after denaturation and dissociation using 8 M urea at pH 7.0. There is a strong affinity between the cofactor and the refolded molecule as no extraneous NAD is required for its reactivation. Results from equilibrium denaturation using parameters like catalytic activity, circular-dichroism, fluorescence emission (both intrinsic and with extraneous fluorophore 1-aniline 8-naphthalene sulphonic acid), 'reductive inhibition' (associated with orientation of NAD on the native enzyme surface), elution profile from size-exclusion HPLC and light scattering have been compiled here. These show that inactivation, integrity of secondary, tertiary and quaternary structures have different transition mid-points suggestive of non-cooperative transition. The unfolding process may be broadly resolved into three parts: an active dimeric holoenzyme with 50% of its original secondary structure at 2.5 M urea; an active monomeric holoenzyme at 3 M urea with only 40% of secondary structure and finally further denaturation by 6 M urea leads to an inactive equilibrium unfolded state with only 20% of residual secondary structure. Thermodynamical parameters associated with some transitions have been quantitated. The results have been discussed with the X-ray crystallographic structure of the enzyme.

Comportamiento de la pendiente en el ensayo de linealidad del Rapigluco-Test / Behavior of the slope in the lineality test of the RapiGluco-Test

Se estudió el comportamiento de la pendiente y el coeficiente de determinación en el ensayo de linealidad del RapiGluco-Test, a partir del análisis de los lotes producidos en 1998. Se examinaron las curvas de calibración mediante un análisis de regresión lineal simple; además, se aplicaron otras herramientas de estadística descriptiva para el análisis de los resultados. Para la evaluación de ensayo de linealidad además del coeficiente de determinación (r2ü0,98), se propuso incluir la pendiente de la curva y se estableció para la aprobación del RapiGluco-Test un rango de 0,058 a 0,064

A pratical method for screening for (beta)-galactosidase secreting microbial colonies

Microbial colonies were replicated on YNB© agar plates overlaid with soft agar containing the glucose-oxidase/peroxidase (BIOTROLr) system. The pink color developed around the colonies was the result of the reaction of this enzyme. This method proved to be very convenient for testing hundreds of colonies grown on agar plates for (beta)-galactosidase secretion by microbial cells.

Juego de reactivos para la determinación de Urea en suero / Kit of reactives to determine serum urea

La determinación de urea reviste gran importancia para el diagnóstico clínico de diversas afecciones, generalmente de origen renal. Se presenta la elaboración de un juego de reactivos basados en el método de Berthelot modificado con salicilato de sodio, el cual introduce el empleo en el laboratorio de un reactivo único: enzima-salicilato, que desarrolla las técnicas de control de calidad y la evaluación integral del juego y se logró linealidad en un rango de concentraciones de urea desde 1 hasta 25 mmol/L. En el estudio de imprecisión se obtuvo un coeficiente de variación menor de 5, tanto para el análisis de la repetibilidad como de la reproductibilidad; el coeficiente de correlación obtenido para la inexactitud fue de 0,999 tomando como referencia el método de la diacetilmonoxima. Se evaluó el comportamiento del método a diferentes niveles de urea en suero desde 2,0 hasta 9,5 mml/L de urea y se reportaron los valores de la media, el coeficiente de variación y la desviación estándar en cada una de estas concentraciones estudiadas

Alkaline phosphatase activity in plasma of pregnant chagasic patients

The Kinetic properties of plasma placental alkaline phosphatase patients with Chagas' disease were studied. When Cl2 Mg was used as activator the same increase of activity (17-20 per cent) was found in the chagasic and non chagasic groups. The enzyme was not inhibited by F-ion in any of the groups. No significant differences were detected between the two groups (chagasic and non chagasic) when the enzyme was treated with inhibitors such as EDTA and L-phenylamine. However, when the CN- ion was used, the enzyme of the normal pregnant women followed a Michaelian curve, whereas in the chagasic group a sigmoideal plot was observed. Thus, the Hill coefficient was 1.1 for the normal group and over 1.5 for the chagasic.

Biochemical studies on citrullus vulgaris urease: stability and reactivation by some reducing agents

Watermelon [Citrullus vulgaris cv. "Giza 1"] urease was inhibited by the divalent metal ions. Mg2+, Ca2+, Ba2+ [10 mM] and Mn2+ [0.02 mM] partially inhibited the enzyme with 15.9, 28.8, 8.0 and 12.0% inhibition, respectively. The heavy metal ions inhibited the enzyme in the order of Hg2+ > Cd2+ > Zn2+ > Cu2+ > Co2+ > Ni2+. Thiols as reducing agents at low concentrations ranging from 0.0001 to 0.01 mM caused activation of the enzyme and preserved its activity. The enzyme was stored in 0.01 mM dithiothreitol and 0.1% penicillin- streptomycin. It was stable and free of bacterial contamination for 6 moths. The specification of this enzyme meets the prerequisites needed for preparation of diagnostic urea kit

Distorsión del mapa enzimático hepático en la hipervitaminosis K3 Aguda / Distortion of the enzimatic pattern of the liver in the acute hypervitaminosis K3

En el presente estudio se describe el efecto de dosis elevadas de vitamina K3 (VK:10 a 50 mg/Kg/día) inyectadas intramuscularmente, durante un lapso de 7 días, sobre la actividad hepática de las siguientes enzimas: glucosa-6-fosfatasa, glucógeno fosforilasa, amilasa, maltasa ácida, proteasas ácidas y alanina y aspartato aminotransferasas en ratas blancas macho y se comparan los resultados con lo que sucede en ratas tratadas con dosis iguales de bisulfito de sodio. En los animales tratados con VK se encontró un aumento significativo en las actividades enzimáticas señaladas, con excepción de la glucógeno fosforilasa, que disminuyó su actividad, y de amilasa, que mostró un comportamiento irregular. Se discuten los resultados obtenidos y se concluye que la VK, a dosis, es potencialmente hepatotóxica, al igual que las otras vitaminas liposolubles (A,D y E).

Actividad de preparados enzimáticos para uso digestivo / Activity of prepared enzymatic for digestive use

Se encontró que las actividades proteolítica y lipolítica de seis preparados enzimáticos para uso gastroenterológico, varían en un ámbito de un orgen de magnitud. La atividad proteolítica es relativamente comparable entre cinco de los seis productos, mientras que la actividd lipolítica es más variable. La calidad entre ellas no es homogénea y no correlaciona con el precio al consumidor. Los resultados sugieren la necesidad de un estricto control de la calidad enzimológica de este tipo de productos.

Estandarización del inmunoanálisis enzimático / Standarization of the enzimatic immunoanalysis

Un método para poner de manifiesto anticuerpos específicos en suero es la variante indirecta de la técnica de ELISA, en la cual un problema habitual es la absorción inespecífica de las inmunoglobulinas del suero a la fase sólida del sistema, lo que dificulta la interpretación correcta de los resultados. En este trabajo se analiza la función que desempeñan varios factores involucrados en la técnica, y con base en los resultados obtenidos se proponen algunas recomendaciones generales para su buen uso