150 research outputs found
Immobilization of old yellow enzymes via covalent or coordination bonds
Ene-reductases (ERs) belonging to the old yellow enzyme (OYE) family have been thoroughly investigated for the stereospecific reduction of activated prochiral C=C double bonds. In this work, OYE3 was immobilized both by covalent binding on glyoxyl-agarose (OYE3-GA), and by affinity-based adsorption on EziG™ particles (OYE3-EziG). The immobilized OYE3-GA was demonstrated to be active (activity recovery = 52%) and to retain almost 100% of its activity under the enzymatic assay conditions (50 mM phosphate buffer pH 7, 28 °C) for six days, whereas the activity of the non-immobilized enzyme dropped to 50% after two days. In the case of EziG™, the highest activity recovery (54%) was achieved by using the most hydrophilic carrier (EziG™ Opal) that was selected for the full characterization of this type of enzyme preparation (stability, recycling, re-use, enzyme leakage). OYE3-EziG was slightly less stable than OYE3-GA under the same experimental conditions. OYE3-GA could be recycled and re-used for up to 12 reaction cycles in the bioreduction of α-methyl-trans-cinnamaldehyde; after 12 runs, the highest conversion achieved was 40%. In the case of the co-immobilized OYE3/GDH-EziG, the conversion dropped to 56% after two reaction cycles. No enzyme leakage was detected over 48 h for both OYE3-GA and OYE3/GDH-EziG (50 mM phosphate buffer pH 7, 28 °C). These seed results pave the way for a true optimization of the immobilization of OYE3, as well as for the use of immobilized OYE3 for preparative applications both in batch and continuous flow conditions
Design of epidermal growth factor immobilization on 3D biocompatible scaffolds to promote tissue repair and regeneration
Exogenous application of human epidermal growth factor (hEGF) stimulates epidermal wound healing. The aim of this study was to develop bioconjugates based on hEGF mimicking the protein in its native state and thus suitable for tissue engineering applications, in particular for treating skin-related disorders as burns. Ribonuclease A (RNase A) was used to investigate a number of different activated-agarose carriers: cyanogen bromide (CNBr)-activated-agarose and glyoxyl-agarose showed to preserve the appropriate orientation of the protein for receptor binding. EGF was immobilized on these carriers and immobilization yield was evaluated (100% and 12%, respectively). A peptide mapping of unbound protein regions was carried out by LC–MS to take evidence of the residues involved in the immobilization and, consequently, the flexibility and surface accessibility of immobilized EGF. To assess cell proliferative activities, 10, 25, 50, and 100 ng/mL of each immobilized EGF sample were seeded on fibroblast cells and incubated for 24, 48 and 72 h. The immobilized growth factor showed significantly high cell proliferative activity at 50 and 100 ng/mL compared to control and soluble EGF. Although both of the immobilized samples show dose-dependency when seeded with high number of fibroblast cells, CNBr-agarose-EGF showed a significantly high activity at 100 ng/mL and 72 h incubation, compared to glyoxyl-agarose-EGF
An enzymatic flow-based preparative route to vidarabine
The bi-enzymatic synthesis of the antiviral drug vidarabine (arabinosyladenine, ara-A), catalyzed by uridine phosphorylase from Clostridium perfringens (CpUP) and a purine nucleoside phosphorylase fromAeromonas hydrophila (AhPNP), was re-designed under continuous-flow conditions. Glyoxyl-agarose and EziGTM1 (Opal) were used as immobilization carriers for carrying out this preparative biotransformation. Upon setting-up reaction parameters (substrate concentration and molar ratio, temperature, pressure, residence time), 1 g of vidarabine was obtained in 55% isolated yield and >99% purity by simply running the flow reactor for 1 week and then collecting (by filtration) the nucleoside precipitated out of the exiting flow. Taking into account the substrate specificity of CpUP and AhPNP, the results obtained pave the way to the use of the CpUP/AhPNP-based bioreactor for the preparation of other purine nucleosides
Mapeamento e análise ambiental de nascentes e cursos d?água da sub-bacia hidrográfica do Tuá, Cruz das Almas, Bahia: um estudo de caso
Um dos maiores desafios para a sobrevivência das comunidades rurais tradicionais do Brasil relaciona-se com o acesso à água em quantidade e qualidade para atender necessidades de consumo humano, dessedentação animal e produção agrícola. Cruz das Almas, como a maioria dos municípios da região do Recôncavo da Bahia, desenvolveu-se desde os tempos do Brasil colônia, explorando os abundantes recursos naturais do bioma Mata Atlântica sem planejamento ou preocupação ambiental com as gerações futuras. A situação dos recursos naturais e, em especial, dos recursos hídricos da zona rural, atingiu patamar crítico de conservação, sendo o fato comprovado pelos resultados obtidos no presente estudo, realizado na sub-bacia do Tuá. O trabalho foi motivado a partir de declarações de agricultores familiares durante a aplicação de ferramentas do diagnóstico rural participativo (DRP) nas comunidade rurais beneficiárias do projeto Quintais Agroflorestais (QuintalSAN). Constatou-se que córregos secaram, matas ciliares despereceram, nascentes estão degradadas e represadas e, a água, imprópria para consumo humano. Diante dessa problemática, a Embrapa Mandioca e Fruticultura, que tem como missão gerar tecnologias para a agricultura brasileira, não se exime da responsabilidade socioambiental de seu entorno. Portanto, nesta perspectiva, a publicação desse documento técnico objetiva contribuir, subsidiar e indicar ao poder público municipal, estadual e à sociedade civil organizada do município de Cruz das Almas, um problema ambiental do meio rural relevante, visando à elaboração premente de um plano de recuperação ambiental para a zona rural do munícipio, seguindo recomendações da agenda 21 brasileira para o desenvolvimento sustentável, e cuja decisão política de remediação dos mesmos foge da abrangência de competência da Embrapa Mandioca e Fruticulturabitstream/item/198280/1/Documento229-Romulo-Romano-Ainfo-2.pd
Mapeamento e análise ambiental de nascentes e cursos d?água da sub-bacia hidrográfica do Tuá, Cruz das Almas, Bahia: um estudo de caso
Um dos maiores desafios para a sobrevivência das comunidades rurais tradicionais do Brasil relaciona-se com o acesso à água em quantidade e qualidade para atender necessidades de consumo humano, dessedentação animal e produção agrícola. Cruz das Almas, como a maioria dos municípios da região do Recôncavo da Bahia, desenvolveu-se desde os tempos do Brasil colônia, explorando os abundantes recursos naturais do bioma Mata Atlântica sem planejamento ou preocupação ambiental com as gerações futuras. A situação dos recursos naturais e, em especial, dos recursos hídricos da zona rural, atingiu patamar crítico de conservação, sendo o fato comprovado pelos resultados obtidos no presente estudo, realizado na sub-bacia do Tuá. O trabalho foi motivado a partir de declarações de agricultores familiares durante a aplicação de ferramentas do diagnóstico rural participativo (DRP) nas comunidade rurais beneficiárias do projeto Quintais Agroflorestais (QuintalSAN). Constatou-se que córregos secaram, matas ciliares despereceram, nascentes estão degradadas e represadas e, a água, imprópria para consumo humano. Diante dessa problemática, a Embrapa Mandioca e Fruticultura, que tem como missão gerar tecnologias para a agricultura brasileira, não se exime da responsabilidade socioambiental de seu entorno. Portanto, nesta perspectiva, a publicação desse documento técnico objetiva contribuir, subsidiar e indicar ao poder público municipal, estadual e à sociedade civil organizada do município de Cruz das Almas, um problema ambiental do meio rural relevante, visando à elaboração premente de um plano de recuperação ambiental para a zona rural do munícipio, seguindo recomendações da agenda 21 brasileira para o desenvolvimento sustentável, e cuja decisão política de remediação dos mesmos foge da abrangência de competência da Embrapa Mandioca e Fruticulturabitstream/item/198280/1/Documento229-Romulo-Romano-Ainfo-2.pd
Batch and Flow Synthesis of Nucleosides by Enzymatic Transglycosylation
Enzymatic methods for the preparation of high-value products have clearly shown their potential in many areas, including nucleic acid chemistry. Enzymes of nucleic acid metabolism such as nucleoside phosphorylases (NPs, EC 2.4.2) can be conveniently used as biocatalysts in the synthesis of nucleoside analogues. These enzymes catalyze the reversible cleavage of the glycosidic bond of (deoxy)ribonucleosides in the presence of inorganic phosphate (Pi) to generate the nucleobase and \u3b1-D-(deoxy)ribose-1-phosphate (phosphorolysis). If a second nucleobase is added to the reaction medium, the formation of a new nucleoside can result (transglycosylation).
Because of its broad substrate specificity [1,2], a purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) was exploited to catalyze the \u201cone-pot, one-enzyme\u201d transglycosylation of 7-methylguanosine iodide with a series of 6-substituted purines, resulting in a moderate to high conversion (18-65%) of the bases into a 22-compound library of 6-substituted purine ribonucleosides [2]. Successively, AhPNP was covalently immobilized [3,4] in a pre-packed column containing aminopropyl silica particles. The resulting AhPNP-IMER (Immobilized Enzyme Reactor) was coupled on-line to a HPLC apparatus containing a semi-preparative chromatographic column. In such a system, \u201cone-enzyme\u201d transglycosylation and product purification were run in a single platform, affording a set of 6-modified purine ribonucleosides at a mg scale [4]. Using this \u201cflow-based\u201d approach, the synthesis of adenine nucleosides through a \u201ctwo-enzyme\u201d transglycosylation was carried out by connecting the AhPNP-IMER to uridine phosphorylase from Clostridium perfringens, immobilized on a silica monolithic column (CpUP-IMER)
Detection of EGFR-Activating and T790M Mutations Using Liquid Biopsy in Patients With EGFR-Mutated Non–Small-Cell Lung Cancer Whose Disease Has Progressed During Treatment With First- and Second-Generation Tyrosine Kinase Inhibitors: A Multicenter Real-Life Retrospective Study
Epidermal growth factor receptor T790M detection using liquid biopsy was evaluated in a real-life setting in 120 advanced non–small-cell lung cancer patients whose disease had progressed during first- or second-generation tyrosine kinase inhibitors. The T790M detection rate was 25.8% using liquid biopsy and 49.2% after tissue rebiopsy. Liquid biopsies performed before disease progression according to Response Evaluation Criteria In Solid Tumors were all negative for T790M and T790M positivity was higher in cases of extrathoracic metastatic sites
b-Initiated processes at the LHC: a reappraisal
Several key processes at the LHC in the standard model and beyond that
involve quarks, such as single-top, Higgs, and weak vector boson associated
production, can be described in QCD either in a 4-flavor or 5-flavor scheme. In
the former, quarks appear only in the final state and are typically
considered massive. In 5-flavor schemes, calculations include quarks in the
initial state, are simpler and allow the resummation of possibly large initial
state logarithms of the type into the
parton distribution function (PDF), being the typical scale of the
hard process. In this work we critically reconsider the rationale for using
5-flavor improved schemes at the LHC. Our motivation stems from the observation
that the effects of initial state logs are rarely very large in hadron
collisions: 4-flavor computations are pertubatively well behaved and a
substantial agreement between predictions in the two schemes is found. We
identify two distinct reasons that explain this behaviour, i.e., the
resummation of the initial state logarithms into the -PDF is relevant only
at large Bjorken and the possibly large ratios 's are
always accompanied by universal phase space suppression factors. Our study
paves the way to using both schemes for the same process so to exploit their
complementary advantages for different observables, such as employing a
5-flavor scheme to accurately predict the total cross section at NNLO and the
corresponding 4-flavor computation at NLO for fully exclusive studies.Comment: Fixed typo in Eq. (A.10) and few typos in Eq. (C.2) and (C.3
The SM and NLO multileg working group: Summary report
This report summarizes the activities of the SM and NLO Multileg Working
Group of the Workshop "Physics at TeV Colliders", Les Houches, France 8-26
June, 2009.Comment: 169 pages, Report of the SM and NLO Multileg Working Group for the
Workshop "Physics at TeV Colliders", Les Houches, France 8-26 June, 200
Early and Late Response and Glucocorticoid-Sparing Effect of Belimumab in Patients with Systemic Lupus Erythematosus with Joint and Skin Manifestations: Results from the Belimumab in Real Life Setting Study—Joint and Skin (BeRLiSS-JS)
Aim. To assess the efficacy of belimumab in joint and skin manifestations in a nationwide cohort of patients with SLE. Methods. All patients with skin and joint involvement enrolled in the BeRLiSS cohort were considered. Belimumab (intravenous, 10 mg/kg) effectiveness in joint and skin manifestations was assessed by DAS28 and CLASI, respectively. Attainment and predictors of DAS28 remission (<2.6) and LDA (≥2.6, ≤3.2), CLASI = 0, 1, and improvement in DAS28 and CLASI indices ≥20%, ≥50%, and ≥70% were evaluated at 6, 12, 24, and 36 months. Results. DAS28 < 2.6 was achieved by 46%, 57%, and 71% of patients at 6, 12, and 24 months, respectively. CLASI = 0 was achieved by 36%, 48%, and 62% of patients at 6, 12, and 24 months, respectively. Belimumab showed a glucocorticoid-sparing effect, being glucocorticoid-free at 8.5%, 15.4%, 25.6%, and 31.6% of patients at 6, 12, 24, and 36 months, respectively. Patients achieving DAS-LDA and CLASI-50 at 6 months had a higher probability of remission at 12 months compared with those who did not (p = 0.034 and p = 0.028, respectively). Conclusions. Belimumab led to clinical improvement in a significant proportion of patients with joint or skin involvement in a real-life setting and was associated with a glucocorticoid-sparing effect. A significant proportion of patients with a partial response at 6 months achieved remission later on during follow-up
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