Efficiency of a new Waitea circinata extract against rice pathogens.

Waitea circinata (Warcup & Talbot) is an orchid antagonist mycorrhizal fungus with biocontrol potential against rice pathogens. This study aimed to optimize the extraction method, obtain a new extract and evaluate its efficiency against rice pathogens in vitro and in vivo, as well as to compare it with other extraction methods and W. circinata. The extracts were obtained and screened for in vitro growth inhibition against the pathogens Cochliobolus miyabeanus, Monographella albescens and Sarocladium oryzae, using the following extracts: mycelial, crude, lyophilized and mycelial mass. An additional in vitro assay was performed with the principal rice pathogen (Magnaporthe oryzae), in order to evaluate the conidial germination and appressorium formation. Based on this evaluation, the lyophilized and mycelial mass extracts were tested in vivo against rice blast (M. oryzae) and compared to the W. circinata mycelial suspension, in different application forms (simultaneous and previous). The mycelial mass extract inhibited all the pathogens, and the crude and lyophilized extracts inhibited C. miyabeanus and M. albescens, respectively. The mycelial mass extract inhibited the M. oryzae conidial germination and appressorium formation by 80 %, and the simultaneous and previous applications suppressed the rice blast by 94 %. These results indicate that the new extract can be used to control rice pathogens

Expression of Trichoderma reesei cellulases CBHI and EGI in Ashbya gossypii

To explore the potential of Ashbya gossypii as a host for the expression of recombinant proteins and to assess whether protein secretion would be more similar to the closely related Saccharomyces cerevisiae or to other filamentous fungi, endoglucanase I (EGI) and cellobiohydrolase I (CBHI) from the fungus Trichoderma reesei were successfully expressed in A. gossypii from plasmids containing the two micron sequences from S. cerevisiae, under the S. cerevisiae PGK1 promoter. The native signal sequences of EGI and CBHI were able to direct the secretion of EGI and CBHI into the culture medium in A. gossypii. Although CBHI activity was not detected using 4- methylumbelliferyl-β-D-lactoside as substrate, the protein was detected by Western blot using monoclonal antibodies. EGI activity was detectable, the specific activity being comparable to that produced by a similar EGI producing S. cerevisiae construct. More EGI was secreted than CBHI, or more active protein was produced. Partial characterization of CBHI and EGI expressed in A. gossypii revealed overglycosylation when compared with the native T. reesei proteins, but the glycosylation was less extensive than on cellulases expressed in S. cerevisiae.Fundação para a Ciência e a Tecnologia (FCT

High-Resolution PTP1B Inhibition Profiling Combined with HPLC-HRMS-SPE-NMR for Identification of PTP1B Inhibitors from Miconia albicans

Protein tyrosine phosphatase 1B (PTP1B) is an intracellular enzyme responsible for deactivation of the insulin receptor, and consequently acts as a negative regulator of insulin signal transduction. In recent years, PTP1B has become an important target for controlling insulin resistance and type 2 diabetes. In the present study, the ethyl acetate extract of leaves of Miconia albicans (IC50 = 4.92 µg/mL) was assessed by high-resolution PTP1B inhibition profiling combined with HPLC-HRMS-SPE-NMR for identification of antidiabetic compounds. This disclosed eleven PTP1B inhibitors, including five polyphenolics: 1-O-(E)-caffeoyl-4,6-di-O-galloyl-β-d-glucopyranose (2), myricetin 3-O-α-l-rhamnopyranoside (3), quercetin 3-O-(2″-galloyl)-α-l-rhamnopyranoside (5), mearnsetin 3-O-α-l-rhamnopyranoside (6), and kaempferol 3-O-α-l-arabinopyranoside (8) as well as eight triterpenoids: maslinic acid (13), 3-epi-sumaresinolic acid (14), sumaresinolic acid (15), 3-O-cis-p-coumaroyl maslinic acid (16), 3-O-trans-p-coumaroyl maslinic acid (17), 3-O-trans-p-coumaroyl 2α-hydroxydulcioic acid (18), oleanolic acid (19), and ursolic acid (20). These results support the use of M. albicans as a traditional medicine with antidiabetic properties and its potential as a source of PTP1B inhibitors

AVALIAÇÃO DA ATIVIDADE ANTIMICROBIANA DA FRAÇÃO BUTANÓLICA DAS FOLHAS DE Cayaponia weddellii FRENTE À BACTÉRIA Enterococcus faecalis

Introdução e objetivos: Enterococcus faecalis é uma bactéria normalmente encontrada na cavidade bucal e responsável por patologias endodônticas primárias e infecções persistentes. O tratamento das infecções endodônticas por E. faecalis são bastante difíceis devido os seus mecanismos de resistência a diversos antimicrobianos1. Dentro deste contexto é possível perceber a importância do estudo de novas moléculas com ação bactericida frente a E. faecalis. Devido à grande diversidade e complexidade, as plantas ainda são uma fonte de novas estruturas que podem se tornar candidatos à fármacos. Cayaponia weddellii é uma planta herbácea conhecida popularmente como purga-de-carijó, cuja raiz é usada no tratamento de sífilis, picada de cobra e edema. O objetivo deste estudo foi avaliar o potencial antimicrobiano da fração butanólica das folhas C. weddellii frente a E. faecalis. Metodologia: O método utilizado para o teste antimicrobiano foi disco difusão em ágar, realizado em placas contendo Ágar Mueller-Hinton. A amostra foi diluída em diferentes concentrações (1x 10-6 mg/mL a 4,2 mg/mL). Penicilina e estreptomicina foram utilizadas como controle positivo. A leitura do teste foi feita de forma qualitativa com o auxílio de uma régua, pela existência ou não do halo inibitório em cada disco. Resultados e discussões: Foi possível identificar halo de inibição do extrato butanóico das folhas C. weddellii na concentração de 0,1mg/ml. Conclusões: A fração butanólica de C. weddellii apresentou um halo de inibição de crescimento intermediário sobre a bactéria E. faecalis. Posteriormente será determinada a concentração inibitória mínima (CIM) para a fração estudada. Agradecimentos: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação de Apoio a Pesquisa do Estado de Goiás (FAPEG)