Let’s stick together for continuous flow biocatalysis

Fusion systems have been designed linking enzymes to cofactors and immobilization modules through appropriate synthetic spacers. These modular biocatalysts (assembling catalysis, cofactor provision/regeneration, and assisted immobilization) are suited for heterogeneous biocatalysis systems and can be efficiently used in continuous flow reactors

Transient analysis of SIRIO using RELAP5/MOD3.3 system code

The main outcome of the present paper is the feasibility analysis of SIRIO (Sistema di rimozione della Potenza di decadimento per Reattori InnOvativi) facility with conditions based on those of its reference facility. The aim of SIRIO project is to study an innovative Decay Heat Removal System (DHRS) for liquid metal reactor and advanced Light Water Reactor (LWR). Such system must ensure passive control of the power removed from the primary system in abnormal condition, and must ensure reactor cooling in both short and long term. This study present numerical simulations developed with RELAP5/MOD3.3, of two operational procedures: the first one is a steady-state and the second one is a transient phase with decay heat generation. The thermal-hydraulic model, developed with RELAP5/MOD3.3, simulates the whole facility including lines, valves, water and gas tanks, and the Molten Salts (MS) gap. Since there is not experimental data, the present paper is a pre-test study based on SIRO facility design

Resolvin D1 Halts Remote Neuroinflammation and Improves Functional Recovery after Focal Brain Damage Via ALX/FPR2 Receptor-Regulated MicroRNAs

Remote damage is a secondary phenomenon that usually occurs after a primary brain damage in regions that are distant, yet functionally connected, and that is critical for determining the outcomes of several CNS pathologies, including traumatic brain and spinal cord injuries. The understanding of remote damage-associated mechanisms has been mostly achieved in several models of focal brain injury such as the hemicerebellectomy (HCb) experimental paradigm, which helped to identify the involvement of many key players, such as inflammation, oxidative stress, apoptosis and autophagy. Currently, few interventions have been shown to successfully limit the progression of secondary damage events and there is still an unmet need for new therapeutic options. Given the emergence of the novel concept of resolution of inflammation, mediated by the newly identified ω3-derived specialized pro-resolving lipid mediators, such as resolvins, we reported a reduced ability of HCb-injured animals to produce resolvin D1 (RvD1) and an increased expression of its target receptor ALX/FPR2 in remote brain regions. The in vivo administration of RvD1 promoted functional recovery and neuroprotection by reducing the activation of Iba-1+ microglia and GFAP+ astrocytes as well as by impairing inflammatory-induced neuronal cell death in remote regions. These effects were counteracted by intracerebroventricular neutralization of ALX/FPR2, whose activation by RvD1 also down-regulated miR-146b and miR-219a-1-dependent inflammatory markers. In conclusion, we propose that innovative therapies based on RvD1-ALX/ FPR2 axis could be exploited to curtail remote damage and enable neuroprotective effects after acute focal brain damage

The Orion Region: Evidence of enhanced cosmic-ray density in a stellar wind forward shock interaction with a high density shell

Context. In recent years, an in-depth gamma-ray analysis of the Orion region has been carried out by the AGILE and Fermi-LAT (Large Area Telescope) teams with the aim of estimating the H2-CO conversion factor, XCO. The comparison of the data from both satellites with models of diffuse gamma-ray Galactic emission unveiled an excess at (l,b)=[213.9, -19.5], in a region at a short angular distance from the OB star k-Ori. Possible explanations of this excess are scattering of the so-called "dark gas", non-linearity in the H2-CO relation, or Cosmic-Ray (CR) energization at the k-Ori wind shock. Aims. Concerning this last hypothesis, we want to verify whether cosmic-ray acceleration or re-acceleration could be triggered at the k-Ori forward shock, which we suppose to be interacting with a star-forming shell detected in several wavebands and probably triggered by high energy particles. Methods. Starting from the AGILE spectrum of the detected gamma-ray excess, showed here for the first time, we developed a valid physical model for cosmic-ray energization, taking into account re-acceleration, acceleration, energy losses, and secondary electron contribution. Results. Despite the characteristic low velocity of an OB star forward shock during its "snowplow" expansion phase, we find that the Orion gamma-ray excess could be explained by re-acceleration of pre-existing cosmic rays in the interaction between the forward shock of k-Ori and the CO-detected, star-forming shell swept-up by the star expansion. According to our calculations, a possible contribution from freshly accelerated particles is sub-dominant with respect the re-acceleration contribution. However, a simple adiabatic compression of the shell could also explain the detected gamma-ray emission. Futher GeV and TeV observations of this region are highly recommended in order to correctly identify the real physical scenario.Comment: 8 pages, 5 figures, accepted by A&

Continuous flow biocatalysis: production and in-line purification of amines by immobilised transaminase from Halomonas elongata

The continuous flow synthesis of a series of amines was successfully achieved by exploiting the enhanced stability and broad substrate scope of an immobilised transaminases from Halomonas elongata (HEWT). A series of substrates were tested in flow reactors and transformed to the corresponding amines in good to excellent yields. The process was implemented with an integrated in-line purification step for the recovery of the pure amines

Recombinant S. cerevisiae expressing Old Yellow Enzymes from non-conventional yeasts: an easy system for selective reduction of activated alkenes

Background: Old Yellow Enzymes (OYEs) are flavin-dependent enoate reductases (EC 1.6.99.1) that catalyze the stereoselective hydrogenation of electron-poor alkenes. Their ability to generate up to two stereocenters by the trans-hydrogenation of the C = C double bond is highly demanded in asymmetric synthesis. Isolated redox enzymes utilization require the addition of cofactors and systems for their regeneration. Microbial whole-cells may represent a valid alternative combining desired enzymatic activity and efficient cofactor regeneration. Considerable efforts were addressed at developing novel whole-cell OYE biocatalysts, based on recombinant Saccharomyces cerevisiae expressing OYE genes.Results: Recombinant S. cerevisiae BY4741{increment}Oye2 strains, lacking endogenous OYE and expressing nine separate OYE genes from non-conventional yeasts, were used as whole-cell biocatalysts to reduce substrates with an electron-poor double bond activated by different electron-withdrawing groups. Ketoisophorone, α-methyl-trans-cinnamaldehyde, and trans-β-methyl-β-nitrostyrene were successfully reduced with high rates and selectivity. A series of four alkyl-substituted cyclohex-2-enones was tested to check the versatility and efficiency of the biocatalysts. Reduction of double bond occurred with high rates and enantioselectivity, except for 3,5,5-trimethyl-2-cyclohexenone. DFT (density functional theory) computational studies were performed to investigate whether the steric hindrance and/or the electronic properties of the substrates were crucial for reactivity. The three-dimensional structure of enoate reductases from Kluyveromyces lodderae and Candida castellii, predicted through comparative modeling, resulted similar to that of S. cerevisiae OYE2 and revealed the key role of Trp116 both in substrate specificity and stereocontrol. All the modeling studies indicate that steric hindrance was a major determinant in the enzyme reactivity.Conclusions: The OYE biocatalysts, based on recombinant S. cerevisiae expressing OYE genes from non-conventional yeasts, were able to differently reduce the activated double bond of enones, enals and nitro-olefins, exhibiting a wide range of substrate specificity. Moreover whole-cells biocatalysts bypassed the necessity of the cofactor recycling and, tuning reaction parameters, allowed the synthetic exploitation of endogenous carbonyl reductases. Molecular modeling studies highlighted key structural features for further improvement of catalytic properties of OYE enzymes

Recombinant S. cerevisiae expressing Old Yellow Enzymes from non-conventional yeasts: an easy system for selective reduction of activated alkenes

Background: Old Yellow Enzymes (OYEs) are flavin-dependent enoate reductases (EC 1.6.99.1) that catalyze the stereoselective hydrogenation of electron-poor alkenes. Their ability to generate up to two stereocenters by the trans-hydrogenation of the C = C double bond is highly demanded in asymmetric synthesis. Isolated redox enzymes utilization require the addition of cofactors and systems for their regeneration. Microbial whole-cells may represent a valid alternative combining desired enzymatic activity and efficient cofactor regeneration. Considerable efforts were addressed at developing novel whole-cell OYE biocatalysts, based on recombinant Saccharomyces cerevisiae expressing OYE genes.Results: Recombinant S. cerevisiae BY4741{increment}Oye2 strains, lacking endogenous OYE and expressing nine separate OYE genes from non-conventional yeasts, were used as whole-cell biocatalysts to reduce substrates with an electron-poor double bond activated by different electron-withdrawing groups. Ketoisophorone, \u3b1-methyl-trans-cinnamaldehyde, and trans-\u3b2-methyl-\u3b2-nitrostyrene were successfully reduced with high rates and selectivity. A series of four alkyl-substituted cyclohex-2-enones was tested to check the versatility and efficiency of the biocatalysts. Reduction of double bond occurred with high rates and enantioselectivity, except for 3,5,5-trimethyl-2-cyclohexenone. DFT (density functional theory) computational studies were performed to investigate whether the steric hindrance and/or the electronic properties of the substrates were crucial for reactivity. The three-dimensional structure of enoate reductases from Kluyveromyces lodderae and Candida castellii, predicted through comparative modeling, resulted similar to that of S. cerevisiae OYE2 and revealed the key role of Trp116 both in substrate specificity and stereocontrol. All the modeling studies indicate that steric hindrance was a major determinant in the enzyme reactivity.Conclusions: The OYE biocatalysts, based on recombinant S. cerevisiae expressing OYE genes from non-conventional yeasts, were able to differently reduce the activated double bond of enones, enals and nitro-olefins, exhibiting a wide range of substrate specificity. Moreover whole-cells biocatalysts bypassed the necessity of the cofactor recycling and, tuning reaction parameters, allowed the synthetic exploitation of endogenous carbonyl reductases. Molecular modeling studies highlighted key structural features for further improvement of catalytic properties of OYE enzymes

Serum angiogenesis associated proteins and clinical outcome in metastatic colorectal cancer patients receiving bevacizumab

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