Trehalose biosynthesis in Thermus thermophilus RQ-1: biochemical properties of the trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase

The genes for trehalose synthesis in Thermus thermophilus RQ-1, namely otsA [trehalose-phosphate synthase (TPS)], otsB [trehalose-phosphate phosphatase (TPP)], and treS [trehalose synthase (maltose converting) (TreS)] genes are structurally linked. The TPS/TPP pathway plays a role in osmoadaptation, since mutants unable to synthesize trehalose via this pathway were less osmotolerant, in trehalose-deprived medium, than the wild-type strain. The otsA and otsB genes have now been individually cloned and overexpressed in Escherichia coli and the corresponding recombinant enzymes purified. The apparent molecular masses of TPS and TPP were 52 and 26 kDa, respectively. The recombinant TPS utilized UDP-glucose, TDP-glucose, ADP-glucose, or GDP-glucose, in this order as glucosyl donors, and glucose-6-phosphate as the glucosyl acceptor to produce trehalose-6-phosphate (T6P). The recombinant TPP catalyzed the dephosphorylation of T6P to trehalose. This enzyme also dephosphorylated G6P, and this activity was enhanced by NDP-glucose. TPS had an optimal activity at about 98°C and pH near 6.0; TPP had a maximal activity near 70°C and at pH 7.0. The enzymes were extremely thermostable: at 100°C, TPS had a half-life of 31 min, and TPP had a half-life of 40 min. The enzymes did not require the presence of divalent cations for activity; however, the presence of Co 2+ and Mg 2+ stimulates both TPS and TPP. This is the first report of the characterization of TPS and TPP from a thermophilic organism

Overview of phlorotannins’ constituents in Fucales

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. Thanks to PTDC/BAA-AGR/31015/2017, “Algaphlor—Brown algae phlorotannins: From bioavailability to the development of new functional foods”, co-financed by the Operational Programme for Competitiveness and Internationalization— POCI, within the European Regional Development Fund (FEDER), and the Science and Technology Foundation (FCT), through national funds. Silva S. thanks FCT for funding through program DL 57/2016–Norma transitória (Ref. SFRH/BPD/74299/2010)

Influence of estimated training status on anti and pro-oxidant activity, nitrite concentration, and blood pressure in middle-aged and older women

The purpose of this study was to compare the association between anti and pro-oxidant activity, nitrite concentration, and blood pressure (BP) in middle-aged and older women with different levels of estimated training status (TS). The sample consisted of 155 females (50-84 years) who were submitted to a physical examination to evaluate estimated TS through the "Functional Fitness Battery Test," BP measurements, and plasma blood samples to evaluate pro-oxidant and antioxidant activity and nitrite concentrations. Participants were separated by age into a middle-aged group (< 65 years) and an older (≥65 years) group and then subdivided in each group according to TS. Blood biochemistry was similar between groups. On the other hand, protein oxidation was lower in participants with higher TS, independent of age. Older females with higher TS presented higher nitrite concentrations, lower lipoperoxidation, and lower values of BP compared with those with lower TS. Lower GPx activity was observed in participants with higher TS compared with middle-aged with lower TS. Thus, our results suggest that good levels of TS may be associated with lower oxidative stress and higher nitrite concentration and may contribute to maintain normal or reduced blood pressure values.Fil: Jacomini, André M.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Dias, Danielle da Silva. Universidade Nove de Julho; BrasilFil: Brito, Janaina de Oliveira. Universidade Nove de Julho; BrasilFil: da Silva, Roberta F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Monteiro, Henrique L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Llesuy, Susana Francisca. Universidade Nove de Julho; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: De Angelis, Kátia. Universidade Nove de Julho; BrasilFil: Amaral, Sandra L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Zago, Anderson S.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Influência das propriedades reológicas do sangue em microcanal com contração simétrica

Neste trabalho recorreu-se à Dinâmica de Fluidos Computacional para simular escoamentos nãonewtonianos em microcanais com estenose simétrica. Para descrever o comportamento não-newtoniano do sangue utilizou-se o modelo de Carreau sendo os resultados obtidos considerando este modelo comparados com os obtidos para fluido newtoniano, o que permitiu avaliar o impacto das propriedades não-newtonianas nos escoamentos estudados

Monitorização das propriedades de textura, organoléticas e microbiológicas de fiambre de perna de porco fatiado e embalado em atmosfera modificada ao longo do seu tempo de vida

O uso de atmosfera modificada (AM), como técnica de conservação na embalagem de produtos fatiados cárnicos, tem sido uma solução eficaz para assegurar a qualidade do produto e prolongar o respetivo tempo de vida útil, podendo alcançar mercados mais longínquos. Amostras de fiambre da perna extra de porco, foram embaladas com uma mistura de gás com 30% de CO2 e 70% de N2, em bandejas termoformadas de APET/EVOH/PE e seladas com filme PE/PVDC. Ao longo de 35 dias foi monitorizada a evolução da composição da mistura de gases, determinados parâmetros físico-químicos, tais como pH, teor de humidade, parâmetros de cor e textura, propriedades organoléticas e microbiológicas. O fiambre foi também avaliado sensorialmente, através de uma análise descritiva quantitativa, em relação ao brilho, cor, aroma, aparência global, flavour, textura (dureza e coesividade) e sabor a sal. Os resultados dos parâmetros físico-químicos não revelaram diferenças significativas ao longo do tempo de armazenamento , com a excepção de alterações na intensidade da cor e ligeiras alterações de textura. O painel detetou diferenças entre produtos frescos e os tempo s mais tardios de armazenamento. Não foram detetad os microrganismos patogénicos em nenhuma das amostras analisadas.Projecto n.º 38869 EXTRASLICED45, co - financiado pelo FEDER através do COMPETE - POFC, no âmbito do QREN 2007 - 201

Tuning of fiber optic surface reflectivity through graphene oxide-based Layer-by-Layer film coatings

SFRH/BD/135820/2018 UID/EEA/50014/2019 UID/FIS/00068/2019 M-ERA-NET2/0002/2016The use of graphene oxide-based coatings on optical fibers are investigated, aiming to tune the reflectivity of optical fiber surfaces for use in precision sensing devices. Graphene oxide (GO) layers are successfully deposited onto optical fiber ends, either in cleaved or hollow microspheres, by mounting combined bilayers of polyethylenimine (PEI) and GO layers using the Layer-by-Layer (LbL) technique. The reflectivity of optical fibers coated with graphene oxide layers is investigated for the telecom region allowing to both monitor layer growth kinetics and cavity characterization. Tunable reflective surfaces are successfully attained in both cleaved optical fibers and hollow microsphere fiber-based sensors by simply coating them with PEI/GO layers through the LbL film technique.publishersversionpublishe

Surface response methodology towards optimal carotenoids production by Gordonia Alkanivorans Strain 1B [Poster]

ABSTRACT: The process of obtaining carotenoids, mainly towards sectors that may influence the human health, such as pharmaceutical and cosmetic, is strictly regulated because of the potential toxicity of the synthetically derived pigments. Thus, microbial pigments are in increasing demand since they are a promising natural and safe alternative source for various industrial applications. Gordonia alkanivorans strain 1B is a fructophilic desulfurizing bacterium, which was also shown to be a good producer of carotenoids. However, its production abilities presented a great variation, depending on the conditions it was submitted to. In previous works, both the carbon source and sulfur source, demonstrated a great influence in the total carotenoid concentration, especially when combined with the presence of a light source. So, in this study, a surface response methodology based on the Doehlert distribution for two factors (% of glucose in a mix glucose + fructose (10 g/L total sugars), and sulfate concentration) was used aiming to get the optimal carotenoids production by G. alkanivorans strain 1B.N/

Influence of culture conditions towards optimal carotenoid production by Gordonia alkanivorans strain 1B

ABSTRACT: With the increasing awareness on the toxicity of several synthetic dyes, demand for pigments from natural sources, such as microbial carotenoids, has gained interest as a promising safe alternative colour additive. In this study, a surface response methodology based on the Doehlert distribution for two factors [% of glucose in a mixture of glucose + fructose (10 g/L total sugars), and sulfate concentration] was used towards the optimal carotenoids production by Gordonia alkanivorans strain 1B in the presence of light (400 lx). Time influence on pigment production by this bacterium was also evaluated, as well as the cell viability profile during longer incubation periods at optimal conditions. Indeed, the highest carotenoid production (2596-3100 mu g/g(DCW)) was obtained when strain 1B was cultivated in the optimal conditions: glucose 10 g/L and sulfate >= 22 mg/L, in the presence of light for 19 days at 30 degrees C, 150 rpm. Flow cytometry showed that the highest production was somehow related with the cellular stress. These results highlight the great potential of strain 1B as a new hyperpigment producer to be exploited towards several applications.info:eu-repo/semantics/publishedVersio