A atividade antimicrobiana de méis produzidos por Melipona asilvai, Melipona quadrifasciata anthidioides, Friseomelita doederleinei, Tetragonisca angustula e Plebeia sp. foi investigada. O teste de difusão em poço demonstrou que todos os méis tem ação antibacteriana frente a Staphylococcus aureus, mas somente as amostras produzidas por M. quadrifasciata anthidioides e F. doederleinei inibiram o crescimento de Escherichia coli. No ensaio de determinação da concentração inibitória mínima, os méis de M. asilvai, M. quadrifasciata anthidioides, F. doederleinei e T. angustula foram mais ativos que os de Plebeia sp. frente a S. aureus e E. coli. Os micro-organismos Pseudomonas aeruginosa e Candida albicans foram resistentes a todos os méis em ambos ensaios. Os méis foram mais efetivos contra as bactérias do que frente a uma solução de açúcar, sugerindo que o mecanismo de inibição do crescimento bacteriano não está somente relacionado ao efeito osmótico. Os resultados obtidos podem explicar o uso medicinal desses méis em doenças bacterianas.

The antimicrobial activity of honey produced by Melipona asilvai, Melipona quadrifasciata anthidioides, Friseomelita doederleinei, Tetragonisca angustula and Plebeia sp. were investigated. The agar well diffusion assay demonstrated that all honeys had antibacterial activity against Staphylococcus aureus, but only the samples from M. quadrifasciata anthidioides and F. doederleinei inhibited the growth of Escherichia coli. In the Minimum Inhibitory Concentration determination assay, M. asilvai, M. quadrifasciata anthidioides, F. doederleinei and T. angustula honeys were more active than that from Plebeia sp. for S. aureus and E. coli. The microorganisms Pseudomonas aeruginosa and Candida albicans were resistant to the all native stingless bee honeys in both assays. Honeys were more effective against bacteria than a sugar solution, suggesting that the mechanism for bacterial growth inhibition is not only related to the osmotic effect. The results of antimicrobial activity may explain the popular medicinal use of these honeys in bacterial diseases.

This work aimed to evaluate the antimicrobial activity of aqueous and methanol extracts of leaves, inflorescences, nut-shell, liquid and solid endosperm nuts of Syagrus coronata against pathogenic bacteria and yeast. Screening was initially performed using the agar dilution method. The extracts regarded as bioactive underwent liquid-liquid partition for determination of their minimum inhibitory concentration and minimum bactericide concentration (MIC and MBC) and those of their respective fractions against the microorganisms inhibited in preliminary tests. Antimicrobial activity was observed only in inflorescences. The corresponding aqueous extract was effective against B. cereus and the three strains of S. aureus, and the corresponding MIC and MCB values were lower than those of dichloromethane, ethyl acetate and butanol fractions of the same extract. The methanol extract was effective against B. cereus, and the corresponding MIC and MBC values were higher than those of ethyl acetate and butanol fractions of the same extract.

Enzimas pectinolíticas de origem microbiana são conhecidas por desempenhar um papel importante comercialmente em uma série de processos industriais. Dois tipos de levedura podem ser distinguidos para a produção dessas enzimas. Um grupo inclui aqueles que têm capacidade de produzi-las na ausência de um indutor e outro grupo compreende as leveduras que as produzem na presença de um indutor. O objetivo deste estudo foi investigar a influência de substâncias pécticas, de glicose, do pH e da temperatura na atividade da poligalacturonase de Kluyveromyces marxianus CCMB 322. O cultivo foi em caldo de fermentação contendo diferentes concentrações de glicose e substâncias pécticas. A atividade da poligalacturonase foi determinada pelo método do DNS, e pH e temperatura otimizados pelo delineamento experimental central composto de experimentos. A poligalacturonase secretada por K. marxianus CCMB 322 foi parcialmente constitutiva, apresentando pH e temperatura ótima de 7,36 e 70 °C, respectivamente e reteve 93% de sua atividade original após 50 minutos a 50 °C. A termoestabilidade da enzima poligalacturonase foi estudada em várias temperaturas (50, 60, 70 e 80 °C) em diferentes tempos de incubação (0, 10, 20, 30, 40 e 50 minutos). Este estudo mostrou que a glicose tem influência na regulação da síntese da poligalacturonase.

Microbial pectinolytic enzymes are known to play a commercially important role in a number of industrial processes. Two kinds of yeast can be discerned regarding the production of enzymes. One group includes those which can produce enzymes in the absence of an inducer, and the other group comprises the yeasts that produce enzymes in the presence of an inducer. The objective of this study was to investigate the influence of pectic substances, glucose, pH, and temperature on the polygalacturonase activity by Kluyveromyces marxianus CCMB 322. The yeast was grown in a fermentation broth containing different concentrations of glucose and pectic substances. The polygalacturonase activity was determined by the DNS method, and the pH and temperature were optimized using a central composite experimental design. The polygalacturonase secreted by K. marxianus CCMB 322 was partially constitutive showing optimum pH and temperature of 7.36 and 70 °C, respectively, and maintained approximately 93% of its original activity for 50 minutes at 50 °C. Thermal stability of the polygalacturonase enzyme was studied at different temperatures (50, 60, 70, and 80 °C) and different incubation times (0, 10, 20, 30, 40, and 50 minutes). This study showed that glucose can influence the regulation of the synthesis of polygalacturonase.

Essential oil from the leaves of Mansoa difficilis was analyzed by GC/MS. Oct-1-en-3-ol (49.65%) was the major compound, but diallyl di- and trisulfide were also present (0.85 and 0.37%, respectively), justifying the garlic-like odor of the crushed leaves. The hexane and methanol extracts of the leaves and stems afforded as main constituents a mixture of linear hydrocarbons, spinasterol, stigmasterol, ursolic and oleanolic acids, two apigenin derivatives and verbascoside. The hexane and methanol extracts of leaves were tested for antimicrobial activity against ten microorganisms. The hexane extract was active against both Psedomonas aeruginosa and Staphylococcus aureus.