Simula����o espacial da perda de solo e nutrientes por eros��o em um argissolo sob cultivo de cana-de-a����car

P��s-gradua����o em Agronomia (Ci��ncia do Solo) - FCAV

Produ����o de poligalacturonase termoest��vel pelo fungo Rhizomucor pusillus A 13.36 em fermenta����o em estado s��lido, purifica����o e caracteriza����o da enzima

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Purifica����o e caracteriza����o bioqu��mica da ��-glicosidase termoest��vel produzida por Thermoascus aurantiacus CBMAI 756

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Purifica����o e caracteriza����o bioqu��mica de poligalacturonases termoest��veis produzidas pelo fungo Thermoascus aurantiacus atrav��s de fermenta����o submersa e fermenta����o em estado s��lido

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Produ����o, isolamento e caracteriza����o de 'beta'-galactosidades de Trichoderma reesei: intera����o de ��ons met��licos na atividade enzim��tica

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Luminesc��ncia e propriedades estruturais de 'LI''TA'O IND.3'nanoestruturado dopado com eur��pio (III) e magn��sio

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Effect of divalent metal ions on the activity and stability of ��-galactosidase isolated from Kluyveromyces lactis

In this study, it was demonstrated that ��-galactosidase can be deactivated and reactivated with EDTA and divalent metal ions. The enzyme was deactivated after 20 minutes in EDTA solution. Maximal deactivation at the lowest EDTA concentration (10-3 mol.L-1) occurred in the presence of Tris-HCl buffer (pH 7.0). The enzyme recovered 50% of its initial activity after 10 minutes at Mg2+concentrations higher than 0.1 mmol.L-1. Experimental concentrations of 0.1 mmol.L-1 Mn2+ and 1.0 mmol.L-1 Co2+ were sufficient to reactivate the enzyme to around 300% of the control activity for the Mn2+ ion and nearly 100% for the Co2+ ion. The enzyme gradually lost its activity when the Co2+ concentration was 10-2 mol.L-1. Ni2+ and Zn2+ were unable to restore the catalytic activity. Km app and Vmax app were 1.95 �� 0.05 mmol.L-1 and 5.40 �� 0.86x10-2 mmol.min-1.mg-1, with o-NPG as substrate. Optimal temperature and pH were 34oC and 7.5. The half-life (t1/2) at 30��C was 17.5 min for the holoenzyme and 11.0 min for the apoenzyme. With respect to pH variation, the apoenzyme proved to be more sensitive than the holoenzyme. Keywords: ��-galactosidase. Divalent metallic ions. Enzyme activity. Stability. RESUMO Efeito de ��ons met��licos divalentes na atividade e estabilidade da ��-galactosidase isolada de Kluyveromyces lactis Este estudo demonstra como a ��-galactosidase pode ser desativada e reativada usando EDTA e ��ons met��licos divalentes. A enzima foi desativada ap��s 20 minutos na presen��a de EDTA. Desativa����o m��xima para a menor concentra����o de EDTA (10-3 mol.L-1) ocorreu na presen��a do tamp��o Tris-HCl. A enzima recuperou 50% de sua atividade inicial ap��s 10 minutos na presen��a de Mg2+ em concentra����es superiores a 0,1mmol.L-1. Concentra����es de 10-4 e 10-3mol.L-1 de Mn2+ e Co2+ foram suficientes para reativar a enzima em 300% comparado ao controle de ��ons Mn2+ e aproximadamente 100% para ��ons Co2+. A enzima perdeu gradualmente a sua atividade quando a concentra����o foi de 10-2 mol.L-1. Ni2+ e Zn2+ foram incapazes de restabelecer a atividade catal��tica. Km app e Vmax app foram 1,95 �� 0,05 mmol.L-1 e 5,40 �� 0,86 x 10-2 mmol.min-1.mg-1. A temperatura e pH ��timos foram 34��C e 7,5. A meia vida da holoenzima foi de 17,5 min a 30��C e para a apoenzima foi de 11,0 min a 30��C. Quanto �� varia����o de pH, a apoenzima provou ser mais sens��vel que a holoenzima. Palavras-chave: ��-galactosidase. ��ons met��licos divalentes. Atividade enzim��tica. Estabilidade.

Propriedades qu��micas e f��sicas do material particulado atmosf��rico e seus efeitos no crescimento de part��culas

P��s-gradua����o em Qu��mica - IQ

Characterization of the co-purified invertase and beta-glucosidase of a multifunctional extract from Aspergillus terreus

The filamentous fungus Aspergillus terreus secretes both invertase and beta-glucosidase when grown under submerged fermentation containing rye flour as the carbon source. The aim of this study was to characterize the co-purified fraction, especially the invertase activity. An invertase and a beta-glucosidase were co-purified by two chromatographic steps, and the isolated enzymatic fraction was 139-fold enriched in invertase activity. SDS-PAGE analysis of the co-purified enzymes suggests that the protein fraction with invertase activity was heterodimeric, with subunits of 47 and 27 kDa. Maximal invertase activity, which was determined by response surface methodology, occurred in pH and temperature ranges of 4.0-6.0 and 55-65 A degrees C, respectively. The invertase in co-purified enzymes was stable for 1 h at pH 3.0-10.0 and maintained full activity for up to 1 h at 55 A degrees C when diluted in water. Invertase activity was stimulated by 1 mM concentrations of Mn2+ (161 %), Co2+ (68 %) and Mg2+ (61 %) and was inhibited by Al3+, Ag+, Fe2+ and Fe3+. In addition to sucrose, the co-purified enzymes hydrolyzed cellobiose, inulin and raffinose, and the apparent affinities for sucrose and cellobiose were quite similar (K-M = 22 mM). However, in the presence of Mn2+, the apparent affinity and V-max for sucrose hydrolysis increased approximately 2- and 2.9-fold, respectively, while for cellobiose, a 2.6-fold increase in V-max was observed, but the apparent affinity decreased 5.5-fold. Thus, it is possible to propose an application of this multifunctional extract containing both invertase and beta-glucosidase to degrade plant biomass, thus increasing the concentration of monosaccharides obtained from sucrose and cellobiose.

Esp��cies ��cidas gasosas e ��ons majorit��rios no material particulado atmosf��rico de uma regi��o agri��cola do Mato Grosso

P��s-gradua����o em Qu��mica - IQ

Utiliza����o de composto org��nico de peixe em aduba����o de capim-marandu

P��s-gradua����o em Zootecnia - FCAV

Daily photosynthesis, water relations, and ion concentrations of uuonymus irrigated with treated wastewater

Euonymus japonica Thunb. (euonymus) plants were submitted for 9 months to two irrigation treatments using water from different sources: a control (C) water with electrical conductivity (EC) less than 1.2 dS.m(-1) and reclaimed wastewater (RW) with EC approximate to 4 dS.m(-1). At the end of the experiment, no differences in the total dry weight were observed between treatments, whereas the leaf dry mass increased (to the detriment of the root part in RW plants). Throughout the day, the stem water potential (Psi(stem)) of the RW plants was lower than in C, whereas stomatal conductance (g(S)) was slightly reduced in RW from 0800 HR to 1200 HR, but no significant variation in photosynthesis (P-n) or energy conversion efficiency (F'(v)/F'(m)) in photosystem II was detected through the effect of salinity. Gas exchange and fluorescence showed a tendency to increase after midday in plants treated with RW. The photosynthetic behavior and fluorescence of RW plants may have been related to the nitrogen and chlorophyll content of the leaves, confirming the resistance of the photosynthetic mechanism to salinity in this species in these conditions. The toxic effects produced by high concentrations of boron (B), sodium (Na+) and chloride (Cl-) were offset by the effect of other ions like magnesium (Mg2+), potassium (K+), and phosphorus (P) in plants irrigated with RW, thus improving their physiological status without decreasing their ornamental value.

Produ����o e avalia����o da estabilidade de enzimas f��ngicas

As enzimas est��o presentes em todas as c��lulas vivas, onde exercem a fun����o de catalisadores das rea����es que comp��em as vias catab��licas e anab��licas do metabolismo celular. Esses biocatalisadores s��o mol��culas de prote��nas e seu poder catal��tico est�� associado �� conforma����o nativa, que depende de condi����es espec��ficas de pH, temperatura e for��a i��nica do meio. Os micro-organismos s��o bastante atrativos para a ind��stria, pois possibilitam a produ����o de enzimas por processos fermentativos em larga escala com regularidade necess��ria e simplicidade na requisi����o nutricional. Assim, embora alguns biocatalisadores sejam extra��dos de tecidos animais e vegetais, as enzimas industriais s��o, em sua maior parte, obtidas a partir de micro-organismos. Este trabalho teve como objetivo a produ����o das enzimas lipase e ��-glucanase a partir dos fungos Aspergillus niger e Trichoderma reesei, respectivamente, em diferentes meios de cultura, para determinar as condi����es de maior produ����o da enzima em quest��o. As enzimas produzidas em agitador orbital foram obtidas a partir da filtra����o do produto da fermenta����o, precipita����o com sulfato de am��nio e liofiliza����o. Ap��s a produ����o e precipita����o a atividade das enzimas e a concentra����o de prote��nas foram quantificadas, os par��metros cin��ticos foram determinados frente a diferentes pHs, temperaturas e for��a i��nica do meio. A lipase apresentou melhor atividade a 30��C e em pH 6,0. A presen��a dos ��ons Mg2+ e Zn2+ levaram a um aumento na atividade da enzima. A ��-glucanase apresentou maiores atividades quando submetidas a 37��C e pH 5,0. Os ��ons Mg2+, Cu2+ e Ca2+ induziram melhor a atividade enzim��tica.

Qualidade e erodibilidade de latossolos sob mata e cultivo de cana-de-a����car

P��s-gradua����o em Agronomia (Ci��ncia do Solo) - FCAV

Efeito do uso do solo sobre seus atributos na microrregi��o de Chapadinha-MA

P��s-gradua����o em Agronomia (Ci��ncia do Solo) - FCAV