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Bifidobacteria are early colonizers of the human gut and play central roles in human health and metabolism. To thrive in this competitive niche, these bacteria evolved the capacity to use complex carbohydrates, including mammalian N-glycans. Herein, we elucidated pivotal biochemical steps involved in high-mannose N-glycan utilization by Bifidobacterium longum. After N-glycan release by an endo-β-N-acetylglucosaminidase, the mannosyl arms are trimmed by the cooperative action of three functionally distinct glycoside hydrolase 38 (GH38) α-mannosidases and a specific GH125 α-1,6-mannosidase. High-resolution cryo-electron microscopy structures revealed that bifidobacterial GH38 α-mannosidases form homotetramers, with the N-terminal jelly roll domain contributing to substrate selectivity. Additionally, an α-glucosidase enables the processing of monoglucosylated N-glycans. Notably, the main degradation product, mannose, is isomerized into fructose before phosphorylation, an unconventional metabolic route connecting it to the bifid shunt pathway. These findings shed light on key molecular mechanisms used by bifidobacteria to use high-mannose N-glycans, a perennial carbon and energy source in the intestinal lumen.

Elucidating cellulose-lignin interactions at the molecular and nanometric scales is an important research topic with impacts on several pathways of biomass valorization. Here, the interaction forces between a cellulosic substrate and lignin are investigated. Atomic force microscopy with lignin-coated tips is employed to probe the site-specific adhesion to a cellulose film in liquid water. Over seven thousand force-curves are analyzed by a machine-learning approach to cluster the experimental data into types of cellulose-tip interactions. The molecular mechanisms for distinct types of cellulose-lignin interactions are revealed by molecular dynamics simulations of lignin globules interacting with different cellulose Iβ crystal facets. This unique combination of experimental force-curves, data-driven analysis, and molecular simulations opens a new approach of investigation and updates the understanding of cellulose-lignin interactions at the nanoscale.

Chiral phonons are concerted mirror-symmetric movements of atomic groups connected by covalent and intermolecular bonds. Finding chiral phonons in biocrystals is fundamentally and technologically important because these lattice vibrations should be highly specific to their short- and long-range organizations. Based on theoretical and experimental data they might be expected but not identified or utilized. Here we show that terahertz chiroptical spectroscopy enables registration and attribution of chiral phonons in microcrystals of numerous amino acids and dipeptides. Theoretical analysis and computer simulations confirm that sharp mirror-symmetric bands observed for left and right enantiomers originate from collective vibrations of biomolecules interconnected by hydrogen bonds into helical chains. Structure-property relationships for strong phonons with rotatory components in biocrystals were also identified. Bladder stones and health supplements display strong spectral signatures of chiral phonons indicating their immediate importance for biomedicine.

Herein we demonstrate that adding single atoms of selected transition metals to graphitic carbon nitrides allows the tailoring of the electronic and chemical properties of these 2D nanomaterials, directly impacting their usage in photocatalysis. These single-atom photocatalysts were successfully prepared with Ni2+, Pt2+ or Ru3+ by cation exchange, using poly(heptazine imides) (PHI) as the 2D layered platform. Differences in photocatalytic performance for these metals were assessed using rhodamine-B (RhB) and methyl orange (MO) as model compounds for degradation. We have demonstrated that single atoms may either improve or impair the degradation of RhB and MO, depending on the proper matching of the net charge of these molecules and the surface potential of the catalyst, which in turn is responsive to the metal incorporated into the PHI nanostructures. Computer simulations demonstrated that even one transition metal cation caused dramatic changes in the electronic structure of PHI, especially regarding light absorption, which was extended all along the visible up to the near IR region. Besides introducing new quantum states, the metal atoms strongly polarized the molecular orbitals across the PHI and electrostatic fields arising from the electronic transitions became at least tenfold stronger. This simple proof of concept demonstrates that these new materials hold promise as tools for many important photocatalytic reactions that are strongly dependent on our ability to control surface charge and its polarization under illumination, such as H2 evolution, CO2 reduction and photooxidation in general.

Abiotic allosterism is most commonly observed in hetero-bimetallic supramolecular complexes and less frequently in homo-bimetallic complexes. The use of hemilabile ligands with high synthetic complexity enables the catalytic center by the addition or removal of allosteric effectors and simplicity is unusually seen in these systems. Here we describe a simpler approach to achieve kinetic regulation by the use of dimeric Schiff base copper complexes connected by a chlorido ligand bridge. The chlorido ligand acts as a weak link between monomers, generating homo-bimetallic self-aggregating supramolecular complexes that generate monomeric species in different reaction rates depending on the solvent and on the radical moiety of the ligand. The ligand exchange was observed by electron paramagnetic resonance (EPR) and conductivity measurements, indicating that complexes with ligands bearing methoxyl (CuIIL2) and ethoxyl (CuIIL5) radicals were more prone to form dimeric complexes in comparison to ligands bearing hydrogen (CuIIL1), methyl (CuIIL3), or t-butyl (CuIIL4) radicals. The equilibrium between dimer and monomer afforded different reactivities of the complexes in acetonitrile/water and methanol/water mixtures toward urea hydrolysis as a model reaction. It was evident that the dimeric species were inactive and that by increasing the water concentration in the reaction medium, the dimeric structures dissociated to form the active monomeric structures. This behavior was more pronounced when methanol/water mixtures were employed due to a slower displacement of the chlorido bridge in this medium than in the acetonitrile/water mixtures, enabling the reaction kinetics to be evaluated. This effect was attributed to the preferential solvation shell by the organic solvents and in essence, an upregulation behavior was observed due to the intrinsic nature of the complexes to form dimeric structures in solution that could be dismantled in the presence of water, indicating their possible use as water-sensors in organic solvents.

Chirality is a unifying structural metric of biological and abiological forms of matter. Over the past decade, considerable clarity has been achieved in understanding the chemistry and physics of chiral inorganic nanoparticles

Gene editing is an important genetic engineering technique that enables gene manipulation at the molecular level. It mainly relies on engineered nucleases of biological origin, whose precise functions cannot be replicated in any currently known abiotic artificial material. Here, we show that chiral cysteine-modified CdTe nanoparticles can specifically recognize and, following photonic excitation, cut at the restriction site GAT'ATC (' indicates the cut site) in double-stranded DNA exceeding 90 base pairs, mimicking a restriction endonuclease. Although photoinduced reactive oxygen species are found to be responsible for the cleavage activity, the sequence selectivity arises from the affinity between cysteine and the conformation of the specific DNA sequence, as confirmed by quantum-chemical calculations. In addition, we demonstrate non-enzymatic sequence-specific DNA incision in living cells and in vivo using these CdTe nanoparticles, which may help in the design of abiotic materials for gene editing and other biological applications.

In recent years, cryogenic electron microscopy (Cryo-EM) has revolutionized the structure determination of wet samples and especially that of biological macromolecules. The glassy-water medium in which the molecules are embedded is considered an almost

In this work, the effect of germination and polishing on the nutritional and technological profile of four different rice cultivars from Brazilian Cerrado were evaluated. The cultivars were germinated, processed and evaluated for the water uptake, germination index, falling number, rapid viscosity analysis and ferulic acid content. The results showed that the germination time for 24 h neither increase the levels of ferulic acid nor caused structural changes in the polysaccharide matrix of these cultivars, except for Moti cultivar. Longer germination times can improve these technological and nutritional aspects.

Complex chiral particles Synthetic colloids are usually smooth, but nature can produce micrometer-scale particles with intricate structure and shape, such as the coccoliths produced by algae. Jiang et al. controlled the self-assembly of gold–cysteine nanoplatelets into a variety of chiral, hierarchically organized colloidal particles by changing the chiral fraction of cysteine and the nucleation temperature. Organic cations created electrostatic repulsions that favored edge assembly of the nanoplatelets, which in turn could create surfaces bearing twisted spikes. Science , this issue p. 642

The deposition of a monolayer nanoarray on the surface of a micrometer-thick substrate is demonstrated, producing rectification characteristics at the nanoscale. The experimental results show that the heterogeneity of the structure and the charge density are the two key factors affecting rectification, which was confirmed with molecular dynamic (MD) and finite element simulations. Moreover, by altering the asymmetric electrolyte environment, the fabricated heterogeneous membrane can be used in energy conversion. This study provides insights into the mechanism underlying the generation of rectification and related factors, providing a theoretical basis for the characteristics of rectification.

An ion-selective electrode (ISE) for monohydrogen phosphate, based on a dispersion of Mg/Al hydrotalcite-like compound particles into a polymeric membrane of polyvinyl butyral, in the coated-wire configuration, is described. The inorganic ionophore was ad hoc synthesized and characterized. The electrode showed a Nernstian response towards monohydrogen phosphate independently from the pH of the solution in the range 4.5–7.8 with a linearity range from 5.0 × 10 −5 to 2.0 × 10 −2 M and a limit of detection of 3.0 × 10 −5 M. The response time varied from 10 to 25 s. Potentiometric selectivity coefficients for the proposed sensor were evaluated over several mono- and divalent anions, chosen among the most common ones. The results pointed out a reasonably good selectivity for monohydrogen phosphate. A successful application of the developed ISE for phosphate determination in hydroxyapatite samples using direct potentiometry is presented.

Gamma-valerolactone (GVL) is a cyclic ester that can be considered a green alternative in chemical processes due to its environmentally friendly physical and chemical properties and low production cost from biomass. Although GVL is a chiral solvent, it is usually used as a racemic mixture, instead of its homochiral forms, which might improve its performance in enantioselective synthesis and chiral separation chromatographic techniques. This report presents the development and validation of an atomistic force field optimized to reproduce GVL liquid-phase properties via Monte Carlo (MC) and molecular dynamics (MD) simulation methods. The optimized force field improved the description of the interactions between pairs of molecules, which is a key aspect for a proper assessment of subtle interactions between the enantiomeric forms of GVL. Inspection of radial distribution functions (RDF) for correlations between RR, SS, and RS interactions found within GVL racemic mixture shows very subtle differences at the first solvation shell. Average interaction energies [Formula: see text], [Formula: see text] and [Formula: see text] for RR, SS, and RS dimer ensembles, respectively, were calculated with force field and also HF-3c and PBEh-3c quantum chemistry methods. For each methodology, resulting values obtained for [Formula: see text] and [Formula: see text] were almost the same and more negative than [Formula: see text]. Also, the average energy fluctuation obtained for RR and SS dimers were higher than the one obtained for RS.

Made available in DSpace on 2018-12-11T17:03:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-10-01 Sugarcane bagasse (SCB) was treated in three stages using ozone oxidation (O), washing in an alkaline medium (B) and ultrasonic irradiation (U). The impact of each pretreatment stage on the physical structure of the SCB was evaluated by its chemical composition, using an infrared technique (FTIR-ATR), and using thermogravimetric analysis (TGA/DTG). The pretreatment sequence O, B, U provided a significant reduction of lignin and hemicellulose, which was confirmed by changes in the absorption bands corresponding to these compounds, when observed using infrared. Thermogravimetric analysis confirmed an increased thermal stability in the treated sample due to the removal of hemicellulose and extractives during the pretreatment. This pretreatment released 391 mg glucose/g from treated SCB after the enzymatic hydrolysis, corresponding to a yield of 94% of the cellulose available. Department of Chemistry and Environmental Science UNESP - Univ. Estadual Paulista - IBILCE, Rua Cristovao Colombo Department of Chemistry and Environmental Science UNESP - Univ. Estadual Paulista - IBILCE, Rua Cristovao Colombo

Two amperometric biosensors based on glassy carbon electrodes (GC) modified with Mg/Al layered double hydroxides (LDHs) containing ferrocene-carboxylate (FcCO2H) or ferrocene-sulfonate (FcSO3H), as interlayer anions, and glucose oxidase (GOx) are presented. Amperometric detection of glucose involves the electrochemical oxidation of H2O2 mediated by the ferrocene derivative. Optimization of the biosensors construction and of the operative conditions was investigated and is discussed herein. The performances of the two biosensors were evaluated by chronoamperometry, working at low anodic potentials (þ 0.400 V for FcCO2H and þ 0.500 V for FcSO3 Hv s. SCE). The linearity extended up to 1.5 mM and 10.0 mM in batch and in flow conditions, respectively, for both biosensors, whereas the sensitivity was higher for the one based on FcCO2H (4.8 � 0.3versus 2.0 � 0.3 m Am M � 1 cm � 2 in batch mode, and 63.9 � 0.4 versus 25.8 � 0.4 m Am M � 1 cm � 2 in flow mode). The biosensors display rapid response time (less than 20 s), good reproducibility, as well as good operational stability. Glucose can be accurately determined in the presence of the most common interferences that coexist in blood serum if an oxidative membrane containing nanoparticles of MnO2 is applied on the biosensors? surface.

Questa pubblicazione a carattere divulgativo illustra gli aspetti salienti di una esperienza di gestione che potrebbe trovare applicazione in contesti simili a quello di origine (dal punto di vista sociale e ambientale), per il controllo e la gestione continuativa in area protetta di questa specie animale. Lo scopo del Piano di controllo adottato è stato quello di gestire la popolazione di cinghiali in modo organico e programmatico con la duplice finalità di ristabilire un equilibrio naturale tra specie e ambiente (obiettivo gestionale) ed allo stesso tempo controllare la diffusione di malattie infettive all’interno della popolazione (obiettivo sanitario). Nonostante il Parco Regionale dei Gessi Bolognesi e Calanchi dell’Abbadessa rientri, secondo il modello di valutazione agro-forestale della Carta delle Vocazioni dell’Emilia Romagna, nell’area di intollerabilità del cinghiale (densità obiettivo 0) (Figura 3), non si è optato per un piano di eradicazione della specie ( ben presente in tutti i territori contigui al parco), bensì è stata fissata una densità obiettivo di 1-1,5 capi ogni 100 ha, stabilita anche sulla scorta di conoscenze di carattere sanitario che vedono postulata la soglia di trasmissione di alcune malattie infettive, al di sotto della quale la malattia tende ad estinguersi. In particolare abbiamo fatto riferimento alla Peste Suina Classica, la cui soglia è stata fissata da Hone et al. (1992), in caso di epidemia causata da un ceppo virale altamente virulento, in 1,4 animali per Km2. Per conseguire questo obiettivo abbiamo inizialmente cercato di ottenere informazioni sia sulla densità sia sulla dinamica di popolazione della specie cinghiale presente nel Parco effettuando, precedentemente all’intervento dei censimenti su pastura, su neve e serali con il faro per stimare quanti fossero all’incirca i cinghiali presenti nell’area e quanti e quali animali prelevare in seguito. Successivamente, a partire dal 2002, abbiamo cercato di prelevare il numero di animali che annualmente veniva stabilito, ricorrendo a metodiche di controllo il più possibile selettive sulla specie e con minimo impatto ambientale. Contemporaneamente sono stati marcati un numero crescente di animali nella popolazione presente all’interno dell’area con la finalità di ottenere una popolazione “densità nota”, strutturata per classi di età e sesso, numericamente compatibile con l’ambiente agroforestale dell’area, che riproponesse una popolazione di cinghiali idealmente presente in questa zona qualora avessero agito su di essa soltanto attraverso fattori di mortalità naturale ( predazione, malattie). Su tutti i cinghiali selvatici a vita libera catturati-marcati/abbattuti sono stati eseguiti, per tutto il periodo oggetto di studio, prelievi ematici e tamponi nasali per le indagini epidemiologico-sanitarie. Lo scopo del presente lavoro è stato quello di dimostrare come sia possibile, a seguito dell’azione simultanea di tecniche di abbattimento selettivo ottenuto attraverso sistemi che non mandino in dispersione i soggetti e attraverso cattura e marcatura di un determinato numero di animali, gestire contemporaneamente dal punto di vista faunistico e sanitario una popolazione di cinghiali in un’area protetta.

Publisher Summary According to recent Italian regulations concerning noise pollution control, each Municipality is bound to classify the territory into areas characterized by homogeneous acoustical features. The elaboration of statistical parameters, like density of population, type and density of human activities, presence of roads, railways, and motorways allows locating areas that are homogeneous as far as noise is concerned. Specific indexes and algorithms based on these parameters can be used for this purpose, and in this context, a fundamental role in data management and coding is hold by Geographic Information Systems (GIS). This chapter gives an overview of a general procedure based on the above-mentioned concepts, together with an example of application to an Italian Municipality located in Tuscany.

Six patients, (four children aged 6 to 12, and two young men aged 17 and 23) affected by the mild form of SMA underwent bilateral isokinetic tests and isokinetic strengthening exercise on the weaker leg three times weekly for 1 month. Children obtained an average of 33% of increase in muscle strength for both extensors and flexors of the knee in the trained leg. Adults obtained a very high increase in peak torque values: 122% for quadriceps and 52% for hamstring muscles. The untrained leg also showed some improvement from 0 to 17%. >