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OBJECTIVES: This study aimed to assess the surface roughness, surface free energy (SFE), and shear bond strength (SBS) on a lithium disilicate glass-ceramic surface following varying etching protocols (time variation) and application of silane either with or without adhesive material. METHODS AND MATERIALS: Lithium disilicate glassceramic (LDGC) computer-aided design and computer-aided manufacture (CAD/CAM) blocks were cut using a slow-speed cutting mechanism. CAD/CAM blocks were then evaluated for surface roughness, 6 groups (n=20); SFE,12 groups (n=5); and SBS, 10 groups (n=10). The cut CAD/CAM blocks were randomly allocated to 28 groups. Groups were based on the following: 30 or 90 seconds of etching with 9% hydrofluoric acid (HF); application or absence of silane coupling agent (Sil); and application or absence of adhesive (Adh).The control group (Cont) had untreated surfaces. Unetched surfaces were surveyed with only silane (Sil), only adhesive (Adh), or silane+adhesive (SilAdh). Further etched groups were HF30 with HF for 30 seconds, HF30-Sil, HF30-Adh, and HF30-SilAdh. Alternative 90-second etching times produced similar groups: HF90, HF90-Sil, HF90-Adh, and HF90-SilAdh. A digital profilometer was used to assess the surface roughness of specimens, and two readings were recorded. Sessile drop analysis was used to examine SFE specimens, and the OWRK model was modified to measure liquid surface tension. A universal testing machine (UltraTester, Ultradent Products, Inc, South Jordan, UT, USA) was utilized for the SBS test, with the crosshead speed set at 0.5 mm/min until failure. Representative treated specimens from each group were submitted to surface morphological evaluation and chemical analysis using scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDXS) (n=3). After data collection, evaluation using one- or two-way analysis of variance and the post-hoc Tukey test (α=5%) was conducted. RESULTS: A longer etching time of 90 seconds produced a rougher surface. After the 90-second etching process, SFE displayed the greatest values; nevertheless, the use of silane did not affect SFE. For every group examined, the application of silane followed by adhesive resulted in an increase in SBS and more stable bonding over time. SEM/EDXS showed that etching times did affect the amount of cerium on the surface and altered surface morphology. CONCLUSIONS: Higher and more consistent bond strengths have been observed with longer etching periods. Silane and adhesive application on the ceramic surface showed stronger and enhanced bond strength, specifically when longer etching times were employed.

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Aqueous two-phase systems have been studied for almost a century to separate biomolecules in harmless conditions. Proteases produced by Aspergillus tamarii URM 4634 were extracted in polyethylene glycol (PEG)/phosphate aqueous two-phase system under discontinuous and continuous (perforated rotative discs column) process. On the discontinuous process, it was evaluated the effect of operational conditions (PEG molar mass and its concentration, phosphate concentration and pH) over the partition coefficient, activity yield and purification factor. Protease partitioned to PEG-phase with partition coefficients up to 55.73. The best process parameters were 17.5% of PEG, with molar mass 8000 g·mol-1, 15% of phosphate salt at pH 6, with 113.15% of activity yield and purification factor of 2.62. Under continuous extraction, hold up data showed that 57.1% of the discontinuous phase was available for protein extraction. Further, separation achieved 90.0% of efficiency. The yields surpassed 100% in almost all runs, and the best purification factor was 1.84, with both flows of 2 mL·min-1. Thus, the best operational conditions reached an activity yield of 95.3% and 90.0% of separation efficiency. Hence, aqueous two-phase system PEG/phosphate extraction is an efficient process for separation of proteases produced by Aspergillus tamarii URM 4634, under continuous extraction likewise under discontinuous process.

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As enzimas fibrinolíticas podem ser obtidas de micro-organismos por meio de processos fermentativos. O presente trabalho teve como objetivo avaliar a produção e extração integrada da protease fibrinolítica de Mucor subtilissimus UCP 1262 usando sistema de duas fases aquosas (SDFA). O processo integrado foi realizado para avaliar a produção, partição e recuperação da protease fibrinolítica, segundo planejamento experimental 23, utilizando como variáveis independentes a massa molar do polietileno glicol (PEG), a concentração do PEG e a concentração do sulfato de sódio. A maior atividade fibrinolítica (15,40U/mL) foi obtida na fase rica em sulfato de sódio no ensaio composto por 10% de sal e 18% de PEG 8000 (g/mol). Recuperações superiores a 80% foram obtidas. A protease fibrinolítica apresentou pH ótimo 7,0, estabilidade entre os pH 6,0 e 8,5, temperatura ótima 50°C, sendo estável de 10°C a 50°C. A enzima foi classificada como uma serino protease, com massa molecular de 52kDa. Como resultado, o processo é notavelmente eficaz para pré-purificar a protease fibrinolítica com baixo custo e rapidez significativa. Quando comparada a outras técnicas de produção e purificação isoladas, a fermentação extrativa é um processo digno a ser substituto das etapas iniciais de separação convencionais.(AU)

Fibrinolytic enzymes can be obtained from microorganisms through fermentative processes. The study aimed to evaluate the fibrinolytic protease production and integrated extraction from Mucor subtilissimus UCP 1262 by extractive fermentation using Aqueous Two-Phase Systems (ATPS). The integrated process was carried out to assess the production, partition and fibrinolytic enzyme recovery, according to a 2 3 -experimental design, using as independent variables Polyethylene glycol (PEG) molar mass, PEG and sodium sulphate concentration, concentration. The highest fibrinolytic activity (15.40U/mL) was obtained in sodium sulfate rich phase in the assay comprising of 10% of salt and 18% of PEG 8000 (g/mol). Yield greater than 80% was obtained. The fibrinolytic protease presented optimum pH 7.0 and stability between pH 6.0 and 8.5, and optimum temperature 50°C, stable between 10°C to 50°C. The enzyme was classified as a serine-protease with 52kDa of molecular weight. As a result, the process is remarkably effective to pre-purify the fibrinolytic protease with a low cost and significantly faster processing time. When compared to other isolated production and purification techniques the extractive fermentation is worthy of being a candidate to replace the initial stages of conventional separation processes.(AU)

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As proteases fibrinolíticas são capazes de degradar coágulos de fibrina formados dentro dos vasos sanguíneos, evitando a trombose intravascular. Em animais, a tromboflebite, que acomete frequentemente os equinos, ocasiona, em seus casos graves, a obstrução jugular e também um edema de laringe, derivando a obstrução das vias aéreas, o que possibilita um edema cerebral, ocorrendo o óbito do animal. Devido ao fato de o tratamento ser de custo elevado, faz-se necessária a investigação de outras fontesde proteases fibrinolíticas com custos menores e com menos efeitos colaterais. Diante disso, este estudo tem como objetivo produzir e caracterizar proteases fibrinolíticas obtidas de Streptomyces parvulus DPUA 1573. Para produção da enzima, foi utilizado um planejamento fatorial 24 avaliando a concentração da farinha de soja (0,5, 1,0 e 1,5%) e da glicose (0, 0,5 e 1,0g/L), temperatura (28, 32 e 37ºC) e agitação (150, 200 e 250rpm) sobre a biomassa e a atividade fibrinolítica. Pode-se verificar que a protease fibrinolítica apresentou atividade máxima (835U/mL) nas condições de concentração de 1,5% de soja, 1g/L de glicose, 28°C e 150rpm com 48 horas de fermentação. A protease fibrinolítica obtida teve temperatura e pH ótimos de 55°C e pH 9,0, respectivamente. A atividade enzimática foi inibida pelo EDTA, pelo íon Fe2+ e pelo SDS, o que indicou a enzima ser uma metaloprotease. A linhagem Streptomyces parvulus DPUA 1573 foi capaz de produzir protease fibrinolítica, possuindo características bioquímicas favoráveis à aplicação na medicina veterinária e possivelmente humana.(AU)

Fibrinolytic proteases are able to degrade fibrin clot formed in the blood vessel, avoiding intravascular thrombosis. In animals, thrombophlebitis often affects horses, and in severe cases causes obstruction of the jugular and laryngeal edema leading to airway obstruction allowing cerebral edema resulting in the death of the animal. Since treatment is costly, the investigation of other sources of fibrinolytic proteases at lower cost and with fewer side effects is needed. Thus, this study aims to produce and characterize fibrinolytic proteases from Streptomyces parvulus DPUA 1573. For enzyme production, a factorial design was performed to evaluate 24 soybean flour concentration (0.5, 1.0 and 1.5%) and glucose (0, 0.5 and 1.0g/L), temperature (28, 32 and 37°C) and agitation (150, 200 and 250rpm) on biomass and fibrinolytic activity. Fibrinolytic protease showed maximum activity (835 U/mL) under these conditions: 1.5% soybean flour, 1g/L glucose, 28°C, and 150rpm 48 hours of fermentation. The optimal temperature was 55°C and optimal pH was 9.0. Fibrinolytic protease activity was inhibited by EDTA, the ion Fe2+, and by SDS, which indicated that the enzyme is a metallo-protease. The strain Streptomyces parvulus DPUA 1573 was able to produce fibrinolytic protease with biochemical characteristics favorable for application in veterinary and human medicine.(AU)

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Actinomicetos são um dos principais produtores de enzimas, vitaminas e metabólitos secundários, destacando-se o gênero Streptomyces, o qual tem uma ampla capacidade de produção de antibióticos eficazes no combate a diferentes microrganismos, entre eles o Staphylococcus sp. Em virtude dessa eficiência no combate a patógenos, o objetivo deste trabalho foi avaliar a produção de metabólitos com atividade antimicrobiana produzidos por 67 Streptomyces isolados de liquens da região amazônica, ante isolados de mastite caprina (Staphylococcus aureus) do estado de Pernambuco, Brasil. Foi utilizado um planejamento fatorial para avaliar a influência das fontes de carbono (glicose) 0%, 0,5% e 1% e de nitrogênio (farinha de soja) 1%, 2,5% e 4% na produção dos antimicrobianos, bem como das variáveis pH, biomassa e atividade antimicrobiana. Dos Streptomyces estudados, o DPUA 1566 foi o que se destacou por formação de halos de inibição entre 18 e 26mm ante os isolados de mastite caprina. Foi possível verificar que a fonte de carbono inibiu a produção de antimicrobianos quando submetidos a uma concentração de glicose de 1%; com a retirada desta, os Streptomyces apresentaram uma elevada capacidade de produção de metabólitos com atividade antimicrobiana tendo potencial para o tratamento de mastite caprina.

Actinomycetes are a leading producer of enzymes, vitamins and secondary metabolites, especially the genus Streptomyces, which have a large capacity for the production of natural antibiotics and are effective against various micro-organisms including Staphylococcus sp. Due to this efficiency in combating micro-organisms, the aim of this study was to evaluate the production of metabolites with antimicrobial activity produced by Streptomyces isolated from lichens 67 in the Amazonia, compared to isolates from goat mastitis (Staphylococcus aureus) in the state of Pernambuco, Brazil. We used a complete factorial design to evaluate the influence of concentrations of carbon sources (glucose) at 0%, 0.5% and 1% and nitrogen (soybean flour) at 1%, 2.5% and 4% in the production of antimicrobial metabolites, and the influence of the pH, microbial biomass and activity variables. Of the studied Streptomyces DPUA 1566 what stood out was the formation of inhibition halos between 18 to 26 mm compared to the isolates from goats mastitis. It was noted that the carbon source inhibited the production of antimicrobial metabolites when subjected to a glucose concentration of 1%. However, after the discontinuation, Streptomyces showed a high capacity to produce metabolites with antimicrobial activity, which has an excellent potential for the treatment of mastitis in goats.

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Avaliou-se a capacidade de 71 actinomicetos isolados de líquens da região amazônica em produzir inibidores de β-lactamases com atividade antimicrobiana sobre Staphylococcus aureus, resistentes à penicilina, isolados de mastite bovina do estado de Pernambuco. A seleção dos actinomicetos produtores de inibidores de β-lactamases foi realizada pela técnica de bloco de gelose contra Klebsiella pneumoniae ATCC 29665, e os actinomicetos selecionados foram testados frente a 17 linhagens de Staphylococcus aureus resistentes à penicilina. Os melhores produtores de inibidores de β-lactamases foram Streptomyces sp. DPUA 1542 e Nocardia sp. DPUA 1571, os quais foram submetidos ao cultivo submerso para determinação da curva de crescimento, pH e atividade antimicrobiana. Os maiores halos de inibição foram obtidos pelos metabólitos produzidos após 96 horas de cultivo tanto para Nocardia sp. - 13,5 e 12,0mm - como para Streptomyces sp. - 8,0 e 14,0mm - com os testes de difusão nos discos e poços, respectivamente. Os resultados permitiram concluir que os actinomicetos são fonte promissora de inibidores de β-lactamases, com potencial uso no tratamento de mastites bovinas.

The ability of 71 actinomycetes, isolated from the Amazon lichens, to produce β-lactamase inhibitors with antimicrobial activity was evaluated against penicillin-resistant Staphylococcus aureus, isolated from bovine mastitis in Pernambuco State. The selection of actinomycetes producers of β-lactamase inhibitors was performed using agar-plug method against Klebsiella pneumoniae ATCC 29665 and the selected actinomycetes were tested against 17 penicillin-resistant Staphylococcus aureus strains. The best producers of β-lactamase inhibitors were Streptomyces sp. DPUA 1542 and Nocardia sp. DPUA 1571. They were submitted to the submerged cultivation to determine the growth and pH curve, and antimicrobial activity. The highest inhibition halo zonewas obtained by metabolites produced after 96 hours of cultivation for both Nocardia sp. (13.5 and 12.0mm) and Streptomyces sp. (8.0 and 14.0mm) with discs and well diffusion tests, respectively. The results showed that the actinomycetes are a promising source of β-lactamase inhibitors, with potential for use in the bovine mastitis treatment.

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The ascorbate oxidase is the enzyme used to determine the content of ascorbic acid in the pharmaceutical and food industries and clinics analyses. The techniques currently used for the purification of this enzyme raise its production cost. Thus, the development of alternative processes and with the potential to reduce costs is interesting. The application of aqueous two-phase system is proposed as an alternative to purification because it enables good separation of biomolecules. The objective of this study was to determine the conditions to continuously pre-purify the enzyme ascorbate oxidase by an aqueous two-phase system (PEG/citrate) using rotating column provided with perforated discs. Under the best conditions (20,000 g/mol PEG molar mass, 10% PEG concentration, and 25% citrate concentration), the system showed satisfactory results (partition coefficient, 3.35; separation efficiency, 54.98%; and purification factor, 1.46) and proved suitable for the pre-purification of ascorbate oxidase in continuous process.

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