Lactoperoxidase enzyme activity and thiocyanate levels in raw milk of Girolando cows

Considering the importance of milk enzymes in milk preservation and animal protection, this study aimed to identify the factors that influence lactoperoxidase activity and levels of thiocyanate in raw milk of Girolando cows, as well as to verify the correlation between these components and the number of somatic cells in cooled raw milk. A total of 181 of milk samples from Girolando cows were used to determine the lactoperoxidase activity, thiocyanate levels, somatic cell number, and serum protein content. The genetic group and the sampling period influenced lactoperoxidase activity. Thiocyanate levels were influenced by the sampling period and by the interaction between the genetic group and the sampling period. The number of somatic cells was influenced by the number of days in lactation, animal age, and sampling period. Milk of animals from the group 1/2 Holstein x Gyr had the highest lactoperoxidase activity and there was no influence of the genetic group on the levels of thiocyanate

Biochemical and thermodynamic characteristics of a new serine protease from Mucor subtilissimus URM 4133

A protease from the fungus Mucor subtilissimus URM 4133, capable of producing bioactive peptides from goat casein, was purified. SDS-PAGE and zymography showed a molecular mass of 30 kDa. The enzyme was active and stable in a wide pH range (6.0–10.5) and (5.0–10.5), respectively. Optimum temperature was at 45–50 °C and stability was above 80 % (40 °C/2 h). Activity was not influenced by ions or organic substances (Triton, Tween, SDS and DMSO), but was completely inhibited by PMSF, suggesting that it belongs to the serine protease family. The Km and Vmax were 2.35 mg azocasein.mL-1 and 333.33 U.mg protein-1, respectively. Thermodynamic parameters of irreversible denaturation (40–60 °C) were enthalpy 123.63 – 123.46 kJ.mol-1, entropy 120.24–122.28 kJ.mol-1 and Gibbs free energy 85.97 – 82.45 kJ.mol-1. Any peptide sequences compatible with this protease were found after analysis by MALDI-TOF, which suggests that it is a new serine protease.info:eu-repo/semantics/publishedVersio

Produção, caracterização e purificação parcial de quitinase produzida por Streptomyces sp. DPUA1581

Sustentabilidade é um tema abordado constantemente nos últimos anos, sendo a produção e utilização de enzimas uma eficiente alternativa na reciclagem de resíduos industriais e agrícolas. A quitinase atua na hidrólise da quitina, esta substância pode ser encontrada em grande quantidade na carapaça de crustáceos. O objetivo desta pesquisa foi selecionar Streptomyces spp. com maior potencial na produção da quitinase, caracterizar o extrato bruto e purificar parcialmente. Para seleção foram utilizadas 30 linhagens de Streptomyces spp. isoladas de líquens da região Amazônica. Foram avaliados parâmetros como pH e temperatura ótimos, estabilidade ao pH e a temperatura a partir do extrato bruto enzimático. A purificação parcial da enzima foi realizada por precipitação em sulfato de amônio na faixa de 0-80% e o perfil eletroforético em SDS-PAGE. Streptomyces sp. DPUA1581 produziu quitinase por fermentação submersa com 1% de quitina, agitação de 150 rpm, a 28 °C por 96h. A caracterização enzimática demonstrou melhor atividade no tampão fosfato de sódio 100 mM, no pH 7,0 e manteve-se estável após 180 minutos em todas as variações de pH testadas. A temperatura ótima da quitinase foi 80 °C, mantendo-se estável entre 30 e 100 °C durante 180 minutos. A atividade foi potencializada na presença de Fe2+ (134%), Mn2+ (71%) e do surfactante aniônico SDS (59%), entretanto, Pb2+ (99%), e EDTA (62%) inibiram a função da enzima. Após o fracionamento com sulfato de amônio o extrato enzimático apresentou fator de purificação igual a 7 e rendimento de 108%. A quitinase produzida por Streptomyces sp. DPUA1581 nas condições descritas neste trabalho, apresenta grande viabilidade industrial, demonstrando atividade catalítica mesmo quando submetida a altas temperaturas por período prolongado.Sustainability is a theme that has been raised steadily in recent years, the production and use of enzymes in an efficient alternative recycling of industrial and agricultural waste. The chitinase acts in the hydrolysis of chitin, the substance can be found in large quantities in the shells of crustaceans. The objective of this research was to select Streptomyces spp. with the greatest potential in the production of chitinase, to characterize the crude and partially purified. For selection we used 30 strains of Streptomyces spp. isolated from lichen in the Amazon region. Parameters such as pH and temperature optima, stability to pH and temperature from the crude enzymatic extract. Partial purification of the enzyme was performed by precipitation in ammonium sulfate in the range of 0-80% and the electrophoresis profile by SDS-PAGE. Streptomyces sp. DPUA1581 chitinase produced by submerged fermentation with 1% of chitin, agitation 150 rpm, at 28 °C for 96 hours. The enzyme characterization showed the best activity in sodium phosphate buffer 100 mM, pH 7.0 and was stable after 180 minutes in all pHs tested. The optimum temperature was 80 °C chitinase, remained stable between 30 and 100 °C for 180 minutes. The activity was enhanced in the presence of Fe2+ (134%), Mn2+ (71%) and the anionic surfactant SDS (59%), however, Pb2+ (99%) and EDTA (62%) inhibited the enzyme function. After fractionation with ammonium sulfate showed the enzymatic extract purification factor equal to 7 and 108% yield. The chitinase produced by Streptomyces sp. DPUA1581 under the conditions described in this work, has a great industrial viability, demonstrating catalytic activity even when subjected to high temperatures for prolonged periods

Potential of quixaba (Sideroxylon obtusifolium) latex as a milk-clotting agent

There are several obstacles to the use of chymosin in cheese production. Consequently, plant proteases have been studied as possible rennet substitutes, but most of these enzymes are unsuitable for the manufacture of cheese. The aim of this study was to evaluate the potential of latex from Sideroxylon obtusifolium as a source of milk-clotting proteases and to partially characterize the enzyme. The enzyme extract showed high protease and coagulant activities, with an optimal pH of 8.0 and temperature of 55 °C. The enzyme was stable in wide ranges of temperature and pH. Its activity was not affected by any metal ions tested; but was inhibited by phenylmethanesulfonyl fluoride and pepstatin. For the coagulant activity, the optimal concentration of CaCl2 was 10 µmol L- 1. Polyacrylamide gel electrophoresis showed four bands, with molecular weights between 17 and 64 kDa. These results indicate that the enzyme can be applied to the cheese industry

Increased interregional virus exchange and nucleotide diversity outline the expansion of chikungunya virus in Brazil

Abstract The emergence and reemergence of mosquito-borne diseases in Brazil such as yellow fever, zika, chikungunya, and dengue have had serious impacts on public health. Concerns have been raised due to the rapid dissemination of the chikungunya virus across the country since its first detection in 2014 in Northeast Brazil. In this work, we carried out on-site training activities in genomic surveillance in partnership with the National Network of Public Health Laboratories that have led to the generation of 422 chikungunya virus genomes from 12 Brazilian states over the past two years (2021–2022), a period that has seen more than 312 thousand chikungunya fever cases reported in the country. These genomes increased the amount of available data and allowed a more comprehensive characterization of the dispersal dynamics of the chikungunya virus East-Central-South-African lineage in Brazil. Tree branching patterns revealed the emergence and expansion of two distinct subclades. Phylogeographic analysis indicated that the northeast region has been the leading hub of virus spread towards other regions. Increased frequency of C > T transitions among the new genomes suggested that host restriction factors from the immune system such as ADAR and AID/APOBEC deaminases might be driving the genetic diversity of the chikungunya virus in Brazil