Extracellular collagenase isolated from Streptomyces antibioticus UFPEDA 3421: purification and biochemical characterization.

Collagenases are proteases able to degrade native and denatured collagen, with broad applications such as leather, food, and pharmaceutical industries. The aim of this research was to purify and characterize a collagenase from Streptomyces antibioticus. In the present work, the coffee ground substrate provided conditions to obtaining high collagenase activity (377.5 U/mL) using anion-exchange DEAE-Sephadex G50 chromatographic protocol. SDS-PAGE revealed the metallo-collagenase with a single band of 41.28 kDa and was able to hydrolyzed type I and type V collagen producing bioactive peptides that delayed the coagulation time. The enzyme activity showed stability across a range of pH (6.0-11) and temperature (30-55 °C) with optima at pH 7.0 and 60 °C, respectively. Activators include Mg+2, Ca+2, Na+, K+, while full inhibition was given by other tested metalloproteinase inhibitors. Kinetic parameters (Km of 27.14 mg/mol, Vmax of 714.29 mg/mol/min, Kcat of 79.9 s-1 and Kcat/Km of 2.95 mL/mg/s) and thermodynamic parameters (Ea of 65.224 kJ/mol, ΔH of 62.75 kJ/mol, ΔS of 1.96 J/mol, ΔG of 62.16 kJ/mol, ΔGE-S of 8.18 kJ/mol and ΔGE-T of -2.64 kJ/mol) were also defined. Coffee grounds showed to be an interesting source to obtaining a collagenase able to produce bioactive peptides with anticoagulant activity.

Properties of Luffa Cylindrica Mats Reinforced Castor Oil-Based Polyurethane Composite as an Alternative for Oriented Strand Board.

The main objective of this work was to produce and characterize a novel ecofriendly castor oil-based polyurethane (COPU) matrix composite reinforced by Luffa cylindrica mats, luffa for short, to be used as panels, as an alternative to oriented strand board (OSB). To do so, the mechanical behavior was evaluated by tree point flexural, perpendicular o surface tensile, screw pullout, and impact tests that were carried on the novel composite along with the neat matrix. Furthermore, the physical characteristics, the thermomechanical behavior, and the functional groups of the materials were observed by water absorption and thickness swelling tests along with dilatometry and Fourier transform infrared spectroscopy (FTIR). A comparison with commercialized OSB was also performed for control. The luffa/COPU composite was prepared by hand lay-up with 48 vol% of luffa mats incorporated as the maximum allowed by the mold under the available resources for manufacturing. The luffa fibers acted as a good reinforcement for the COPU matrix, where the flexural strength and modulus of elasticity were increased by more than 23 and 10 times, respectively, and the other mechanical properties more than doubled for the composites compared to the neat COPU resin. In general, the composite presented a lower performance compared to the commercial OSB, with the impact results being the exception. The water absorption and thickness swallowing results showed an already-expected behavior for the studied materials, where the better performance was found for the hydrophobic neat resin. The FTIR revealed that there was little interaction between luffa and COPU resin, which can be translated to a weak interface between these materials. However, the mechanical behavior, together with the other results presented by the luffa/COPU composite, confirm it is more than enough to be used as civil construction panels such as OSB.

Purification and characterization of a protease from Aspergillus sydowii URM5774: Coffee ground residue for protease production by solid state fermentation.

Solid state fermentation is a promising technology largely used in biotechnology process and is a suitable strategy for producing low-cost enzymatic products. At the present study, a novel enzyme obtained through solid state fermentation using Aspergillus sydowii was herein purified and characterized. The fermentations used coffee ground residue as substrate and the crude enzyme was submitted through further purification steps of: acetonic precipitation, DEAE-Sephadex and Superdex G-75 column. Both crude and purified enzymes were submitted to biochemical characterization of their thermostability, optimal temperature and pH, effects of inhibitors and metal ions. A purified protease was obtained with yield of 5.9-fold and 53% recovery, with maximal proteolytic activity of 352.0 U/mL. SDS-PAGE revealed a band of protein at 47.0 kDa. The enzyme activity was abolished in the presence of phenyl-methyl sulfonyl fluoride and partially inhibited against Triton X-100 (78.0%). The optimal activity was found in pH 8.0 at 45°C of temperature. Besides, the enzyme showed stability between 35°C and 50°C. It was possible to determine appropriate conditions to the obtainment of thermostable proteases with biotechnological interest associated with a method that concomitantly shows excellent production levels and recovery waste raw material in a very profitable process.

Perda por degelo em carcaças de frangos congeladas / Ice break up loss on frozen chicken carcasses

O consumo de frango congelado aumentou nos últimos anos. O fator de degelo, água absorvida pelo músculo da ave durante o processamento industrial, é um indicador de qualidade e economicidade para este produto. Com objetivo de avaliar perdas de peso por degelo em carcaças de frango, por meio do método de gotejamento (Drip test), foram analisadas 25 amostras de 5 diferentes marcas (10 evisceradas e 15 não evisceradas). Os resultados das amostras individuais demonstraram que das 25 amostras, 14 amostras (56%) evidenciaram perda por degelo acima do permitido pela legislação pertinente que é de 6%. Observou-se também que as amostras com vísceras tiveram médias de perda por degelo bem superiores àquelas evisceradas: 7,3% e 5,2%, respectivamente. Considerando valores médios de 5 amostras por marca, apenas as com vísceras apresentaram não conformidade em relação à perda de peso por degelo. Todas as amostras contendo vísceras apresentaram irregularidades e 20% das amostras evisceradas tiveram percentual de degelo ligeiramente acima do máximo permitido. Diante dos resultados concluiu-se que: as condições "eviscerado" e "não eviscerado" influenciaram sobremaneira os valores de perda por degelo, que a maioria das amostras analisadas apresentou percentuais elevados de degelo e que a aquisição de carcaça eviscerada é a melhor opção de compra para este tipo de produto considerando a economicidade.

Complete genome sequence of the sugarcane nitrogen-fixing endophyte Gluconacetobacter diazotrophicus Pal5.

BACKGROUND: Gluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. It has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins. RESULTS: Gluconacetobacter diazotrophicus Pal5 is the third diazotrophic endophytic bacterium to be completely sequenced. Its genome is composed of a 3.9 Mb chromosome and 2 plasmids of 16.6 and 38.8 kb, respectively. We annotated 3,938 coding sequences which reveal several characteristics related to the endophytic lifestyle such as nitrogen fixation, plant growth promotion, sugar metabolism, transport systems, synthesis of auxin and the occurrence of bacteriocins. Genomic analysis identified a core component of 894 genes shared with phylogenetically related bacteria. Gene clusters for gum-like polysaccharide biosynthesis, tad pilus, quorum sensing, for modulation of plant growth by indole acetic acid and mechanisms involved in tolerance to acidic conditions were identified and may be related to the sugarcane endophytic and plant-growth promoting traits of G. diazotrophicus. An accessory component of at least 851 genes distributed in genome islands was identified, and was most likely acquired by horizontal gene transfer. This portion of the genome has likely contributed to adaptation to the plant habitat. CONCLUSION: The genome data offer an important resource of information that can be used to manipulate plant/bacterium interactions with the aim of improving sugarcane crop production and other biotechnological applications.

Avaliação de hábitos de higiene bucal em portadores de próteses removíveis da Faculdade de Odontologia da Universidade Federal de Sergipe / Evaluation of removable prostheses wearers’ oral hygiene habits from Faculty of Odontology, in Universidade Federal de Sergipe

Introdução: a reabilitação oral de pacientes realizada com próteses removíveis parciais ou totais visa devolver-lhes estética e função. Para que o tratamento seja bem sucedido faz-se necessário que estes indivíduos sejam orientados a manter adequada higiene bucal e de suas próteses. Assim, o objetivo deste estudo foi conhecer os métodos e hábitos de higiene de usuários de prótese removível, e se receberam orientação do cirurgião-dentista no momento em que as próteses foram instaladas. Método: participaram do estudo 30 portadores de prótese removível atendidos na clínica do Departamento de Odontologia da Universidade Federal de Sergipe. Os sujeitos da pesquisa foram entrevistados e suas próteses avaliadas quanto à higiene. Em seguida, os participantes foram instruídos sobre a importância da higiene oral, recebendo uma cartilha com instruções. Os resultados foram tabulados no Microsoft Excel 2003® e apresentados na forma de gráficos e tabelas. Resultados: observou-se que 53por cento dos pesquisados nunca foram orientados quanto a higienização, e o método mecânico foi o mais utilizado para higienizar os dentes remanescentes e a prótese, numa freqüência de três ou mais vezes ao dia (77por cento). A higiene das próteses apresentou-se moderada (1,48 para a superior e 1,09 para a inferior) de acordo com o escore utilizado neste trabalho (0 a 3). Conclusão: os participantes do estudo, apesar de higienizar suas próteses e dentes com freqüência, não utilizavam métodos adequados. Faz-se necessário, portanto, que os dentistas dêem instruções aos seus pacientes de como limpar seus dentes e as próteses para que a higiene oral seja mantida a fim de prevenir as patologias orais.