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We designed and built a compact device capable of measuring electronic transport in atomic-sized contacts. This experimental setup is based on the break-junction (BJ) approach. According to the samples used as electrodes, we named the instrument a Surface-Tip Break Junction. Our instrument, like a scanning tunnelling microscope in the BJ configuration, can measure the quantum transport in atoms captured by electrodes. In our case, to measure this transport, we included a homemade I–V converter, a low-cost oscilloscope, and a mobile phone that functions as a data acquisition system. Moreover, we developed a protocol to analyse the digitized data obtained from the oscilloscope. This low-cost pedagogical setup offers the possibility of implementation in undergraduate and graduate laboratories. C S thanks for the financial support to Generalitat Valenciana through CIDEXG/2022/45, CDEIGENT/2018/028, and Banco Santander through the MOVSANTANDER 2020 program. Becas Iberoamérica Santander Investigación—Santander Universidades 2020.

We have carried out the synthesis of two dithia[9]helicenes by means of a LED-based double photocyclization. The compounds have sulfur atoms placed at the terminal rings of the helicene, and they display two alternative C2-symmetrical arrangements named exo (1) and endo (2). Separation of enantiomers of opposite helicity allowed the complete characterization of their chiroptical properties in solution, in silico, by X-ray crystallography, and adsorbed on gold. The theoretical analysis confirms the unexpected finding that endo-dithia[9]helicene displays an experimental dissymmetry factor in CPL (glum) larger than its isomer, exo-dithia[9]helicene. This enhanced glum factor ranks among the largest for a helicene-type molecule. Comparison with smaller analogues, namely exo and endo-dithia[7]helicenes (10 and 11, respectively), is also presented. AG and CU thank the financial support by the Spanish MICIIN (PID2019-109539GB-C41), the Generalitat Valenciana (PROMETEO/2021/017), and the University of Alicante (VIGROB-285). CS thanks for the financial support by the Generalitat Valenciana through CDEIGENT2018/028. The computational resources provided by the Department of Applied Physics of the University of Alicante are greatly appreciated. JA and PM thank the National Science Foundation, grant CHE-1855470, for support of the theoretical component of this study, and the Center for Computational Research (CCR) at UB for providing computational resources. J.C. thanks the the Ministère de l’Education Nationale, de la Recherche et de la Technologie and the Centre National de la Recherche Scientifique (CNRS).

After evaporation of the organic solvents, benzene, toluene, and cyclohexane on gold substrates, Scanning Tunneling Microscope (STM) shows the presence of a remaining adsorbed layer. The different solvent molecules were individually observed at ambient conditions, and their electronic transport properties characterized through the STM in the Break Junction approach. The combination of both techniques reveals, on one hand, that solvents are not fully evaporated over the gold electrode and, secondly, characterize the electronic transport of the solvents in molecular electronics. This work was supported by the Spanish Government (MAT2016-78625-C2 and PID2019-109539 GB-C41) and the Generalitat Valenciana through PROMETEO/2017/139 and program CDEIGENT/2018/028.

Aims: To improve the nutri-functional quality of chickpea flour by fermentation with selected lactic acid bacteria (LAB) to formulate functional legume-derived products. Methods and Results: A Randomized Complete Block Design was carried out to assess the influence of experimental conditions (presence/absence of Lactiplantibacillus plantarum CRL2211 and/or Weissella paramesenteroides CRL2182, temperature, time and dough yield) on LAB population, acidification, antinutritional factors and total phenolic contents (TPCs) of chickpea flour. Fermentation with both strains for 24 h at 37°C produced an increase in LAB (up to 8.9 log CFU/g), acidity (final pH 4.06), TPC (525.00 mg GAE/100 g) and tannin and trypsin inhibitor removal (28.80 mg GAE/100 g and 1.60 mg/g, respectively) higher than the spontaneously fermented doughs. RAPD and Rep-PCR analysis revealed that fermentation was dominated by L. plantarum CRL2211. Molecular docking and dynamics simulations were useful to explain LAB enzyme behaviour during fermentation highlighting the chemical affinity of LAB tannases and proteinases to gallocatechin and trypsin inhibitors. Compared with other processing methods, fermentation was better than soaking, germination and cooking for increasing the techno-functional properties of chickpea flour. Fermented doughs were applied to the manufacture of crackers that contained 81% more TPC and 64% more antioxidant activity than controls. Conclusions: Fermentation for 24 h at 37°C with selected autochthonous LAB was the best method for improving the quality of chickpea flour and derived crackers type cookies. Significance and Impact of Study: Chickpea is suitable for the development of novel functional foods. Fermentation with selected LAB would improve the final product quality and bioactivity. The combination of experimental and simulation approaches can lead to a better understanding of the fermentation processes to enhance the properties of a food matrix., This work was supported by PIP 0319 from CONICET, PICT2014‐3583 and PICT2019‐3504 from ANPCyT and Projects IC‐601 and IC‐802 from Universidad de San Pablo‐Tucumán, Argentina. Carlos Sabater acknowledges his Postdoctoral research contract funded by the Instituto de Investigación Sanitaria del Principado de Asturias (ISPA) and Postdoctoral research contract Juan de la Cierva‐Formación from Spanish Ministry of Science and Innovation (FJC2019‐042125‐I).

Here we report on the identification and characterization of suspended double-stranded Au atomic chains up to ∼4 atoms long, using a scanning tunneling microscope adapted for the fabrication and simultaneous recording of the conductance. These chains are one of the smallest structures with the highest stability connecting two metallic electrodes, identified from the evolution of the conductance in the process of the controlled breakage of the contact between two metals. Molecular dynamics simulations and density functional theory electron transport calculations help us to unveil the richness of the geometric structures appearing in the experiments in the form of double-stranded chains, their stability, and how these can evolve into the formation of monoatomic chains. This work was supported by the Generalitat Valenciana through PROMETEO2017/139, the Spanish government through Grants MAT2016-78625-C2-1-P, FIS2016-80434-P, and PID2019-109539GB-C4, and the Marı́a de Maeztu Programme for Units of Excellence in R&D (CEX2018-000805-M); by Comunidad Autónoma de Madrid through Grant S2018/NMT-4321 (NanomagCOST-CM), by the Fundación Ramón Areces, and by the European Union Graphene Flagship under Grant No. 604391. C.S. gratefully acknowledges financial support from Generalitat Valenciana with the programs GENT (CDEIGENT2018/028). J.J.P. acknowledges the computer resources and assistance provided by the Barcelona Supercomputing Center (FI-2019-2-0007) and the Universidad Autónoma de Madrid.

Diet is one of the most important factors determining the population profile of the members of the human intestinal microbiota and modulating its activity. Diet provides the necessary nutrients for maintaining our physiological state, it also supplies specific substrates that can be metabolized by the intestinal microbiota in order to carry out its biological functions, as well as food microorganisms, naturally present in the food or added through supplements, whose interaction with our cells conditions our state of health. This chapter collects recent information on how the microbiota can be modulated through different foods and diets, as well as with probiotics, prebiotics and other related compounds.

Aim: There is growing evidence that physical activity modulates gut microbiota composition through complex interactions between diet and microbial species. On the other hand, next-generation sequencing techniques include shotgun metagenomics and 16S amplicon sequencing. These methodologies allow a comprehensive characterisation of microbial communities of athletes from different disciplines as well as non-professional players and sedentary adults exposed to training. This systematic review summarises recent applications of next-generation sequencing to characterise the athletic gut microbiome. Methods: A systematic review of microbiome research was performed to determine the association of microbiota composition profiles with sports performance. Results: Bibliographic analysis revealed the importance of a novel research trend aiming at deciphering the associations between individual microbial species and sports performance. In addition, literature review highlighted the role of butyrate-producing bacteria such as Anaerostipes hadrus, Clostridium bolteae, Faecalibacterium prausnitzii, Roseburia hominis and unidentified species belonging to Clostridiales, Lachnospiraceae and Subdoligranulum species in gut health and sports performance across several disciplines. Interestingly, metabolic activities of Prevotella copri and Veillonella atypica involved in branched amino acid and lactate metabolism may contribute to reducing muscular fatigue. Other microbial metabolic pathways of interest involved in carbohydrate metabolism showed increased proportions in athletes´ metagenomes. Conclusion: Future research will aim at developing personalised nutrition interventions to modulate key species associated with certain components of exercise.

This article belongs to the Special Issue Microbial Impact on Cholesterol and Bile Acid Metabolism., Gallbladder metagenome involves a wide range of unidentified sequences comprising the so-called metagenomic dark matter. Therefore, this study aimed to characterise three gallbladder metagenomes and a fosmid library with an emphasis on metagenomic dark matter fraction. For this purpose, a novel data analysis strategy based on the combination of remote homology and molecular modelling has been proposed. According to the results obtained, several protein functional domains were annotated in the metagenomic dark matter fraction including acetyltransferases, outer membrane transporter proteins, membrane assembly factors, DNA repair and recombination proteins and response regulator phosphatases. In addition, one deacetylase involved in mycothiol biosynthesis was found in the metagenomic dark matter fraction of the fosmid library. This enzyme may exert a protective effect in Actinobacteria against bile components exposure, in agreement with the presence of multiple antibiotic and multidrug resistance genes. Potential mechanisms of action of this novel deacetylase were elucidated by molecular simulations, highlighting the role of histidine and aspartic acid residues. Computational pipelines presented in this work may be of special interest to discover novel microbial enzymes which had not been previously characterised., This study was supported by MINECO (Spanish Ministry of Economy and Competitiveness) under grant number AGL2013-44761-P, supported by FEDER (The European Regional Development Funds). NM was the recipient of an FPI Predoctoral Grant (BES-2014-068736) from MINECO. CS is a postdoctoral researcher supported by the Juan de la Cierva-Formación Postdoctoral Trainee Program from MICINN, the Spanish Ministry of Science and Innovation (FJC2019-042125-I).

In this work, two Peruvian beverages "Masato de Yuca," typical of the Amazonian communities made from cassava (Manihot esculenta), and "Chicha de Siete Semillas," made from different cereal, pseudo-cereal, and legume flours, were explored for the isolation of lactic acid bacteria after obtaining the permission of local authorities following Nagoya protocol. From an initial number of 33 isolates, 16 strains with different RAPD- and REP-PCR genetic profiles were obtained. In Chicha, all strains were Lactiplantibacillus plantarum (formerly Lactobacillus plantarum), whereas in Masato, in addition to this species, Limosilactobacillus fermentum (formerly Lactobacillus fermentum), Pediococcus acidilactici, and Weissella confusa were also identified. Correlation analysis carried out with their carbohydrate fermentation patterns and enzymatic profiles allowed a clustering of the lactobacilli separated from the other genera. Finally, the 16 strains were submitted to a static in vitro digestion (INFOGEST model) that simulated the gastrointestinal transit. Besides, their ability to adhere to the human epithelial intestinal cell line HT29 was also determined. Following both procedures, the best probiotic candidate was Lac. plantarum Ch13, a robust strain able to better face the challenging conditions of the gastrointestinal tract and showing higher adhesion ability to the intestinal epithelium in comparison with the commercial probiotic strain 299v. In order to characterize its benefit for human health, this Ch13 strain will be deeply studied in further works.

The study of the food microbiome has gained considerable interest in recent years, mainly due to the wide range of applications that can be derived from the analysis of metagenomes. Among these applications, it is worth mentioning the possibility of using metagenomic analyses to determine food authenticity, to assess the microbiological safety of foods thanks to the detection and tracking of pathogens, antibiotic resistance genes and other undesirable traits, as well to identify the microorganisms responsible for food processing defects. Metataxonomics and metagenomics are currently the gold standard methodologies to explore the full potential of metagenomes in the food industry. However, there are still a number of challenges that must be solved in order to implement these methods routinely in food chain monitoring, and for the regulatory agencies to take them into account in their opinions. These challenges include the difficulties of analysing foods and food-related environments with a low microbial load, the lack of validated bioinformatics pipelines adapted to food microbiomes and the difficulty of assessing the viability of the detected microorganisms. This review summarizes the methods of microbiome analysis that have been used, so far, in foods and food-related environments, with a specific focus on those involving Next-Generation Sequencing technologies.

Conductance measurements in single-molecule junctions (SMJs) are on many occasions accompanied by inelastic spectroscopy and shot-noise measurements in order to obtain information about different vibration modes (or vibrons) and channels involved in the transport respectively. We have extended the single-molecule shot-noise measurements, which were previously performed at low bias, to high bias and we have studied the effects of these vibrons on the noise for a Deuterium (D2) molecule between Pt leads. We report here two important findings from these measurements. First, we find in our noise measurements that at the vibron energies of the molecule, a two-level fluctuation (TLF) is excited in the junction. Second, we show that in the presence of this TLF, a form of enhanced noise spectroscopy can be performed to detect inelastic electron–vibron interactions, by studying the third derivative of the noise (d3SI/dV3). This is possible because TLFs are insensitive to elastic scattering of electrons from defects, which nevertheless leave their signature in the usual inelastic electron tunnelling spectroscopy (IETS) measurements. This work was supported by the Netherlands Organization for Scientific Research (NWO/OCW), as part of the Frontiers of Nanoscience program with grant number NF13SAP09.

There is no doubt that in recent years there has been a growing interest in the use of by-products from the agri-food industry with the aim of achieving zero waste. In this context, pectin is a valuable ingredient obtained from vegetable and fruit by-products whose extraction may be a problem rather than a solution. It was not until 2015 when studies began to be published on the need to avoid residues derived from pectin extraction. We show an exhaustive analysis of the existing bibliography on the possible ways for comprehensive use of these residues from a biorefinery approach. In addition, we have carried out a bibliometric analysis of 27 articles reporting by-product composition and high-value ingredient recovery, making a comparison of specific biorefinery applications described in selected articles. A general overview is provided on valorisation strategies, considering the carbohydrate composition (mono-/disaccharides, pectin, cellulose and hemicellulose) of fruit and vegetable by-products. Integrated utilisation strategies should start with the recovery of compounds soluble in organic solvents (essential oils, polyphenols, carotenoids, etc.), followed by the recovery of pectin and subsequent use of depectinised residues. Biofuels (bioethanol, biogas or solid biofuel) can be obtained by transforming the secondary flows by physicochemical or biological processes such as ethanolic fermentation or anaerobic digestion. Other fermentation processes allow organic acids such as succinic, lactic, butyric and mucic acids to be obtained, as well as other compounds such as bacterial cellulose and pullulan. The role of up to 40 microbial glycosidases in fermentation involved in biorefinery applications was also highlighted. Finally, other uses of waste biomass such as composting or animal feed are considered. Although most of the research has been carried out on citrus, this review points out that, despites the differences, studies with these by-products can help in the efficient utilisation of other types of agri-food wastes., Carlos Sabater acknowledges his Postdoctoral research contract funded by the Instituto de Investigación Sanitaria del Principado de Asturias (ISPA) and Postdoctoral research contract Juan de la Cierva-Formación from Spanish Ministry of Science and Innovation (FJC2019-042125-I). This work has been funded by the Spanish Ministry of Science and Innovation through projects AGL2014-53445-R/AGL2017-84614-C2-1-R.

Under the challenge of growing a single bilayer of Bi oriented in the (111) crystallographic direction over amorphous substrates, we have studied different thicknesses of Bi thermally evaporated onto silicon oxide in order to shed light on the dominant atomic structures and their oxidation. We have employed atomic force microscope, X-ray diffraction, and scanning electron microscope approaches to demonstrate that Bi is crystalline and oriented in the (111) direction for thicknesses over 20 nm. Surprisingly, Raman spectroscopy indicates that the rhombohedral structure is preserved even for ultra-thin layers of Bi, down to $\sim 5$ nm. Moreover, the signals also reveal that bismuth films exposed to ambient conditions do not suffer major surface oxidation., 6 pages,4 figures

The aim of this work was to develop a comprehensive workflow to elucidate molecular features of artichoke pectic oligosaccharides (POS) contributing to high potential prebiotic activity. First, obtainment of artichoke POS by Pectinex® Ultra-Olio was optimised using an artificial neural network. Under optimal conditions (pH 6.86; 1.5 h; enzyme dose 520.5 U/g pectin) POS yield was 624 mg/g pectin. Oligosaccharide structures (Mw < 1.3 kDa) were characterised by MALDI-TOF-MS. Then, conformational analysis of glycosidic bonds was performed by replica exchange molecular dynamics simulations and interaction mechanisms between POS and several microbial glycosidases were proposed by molecular modelling. Chemical information was integrated in virtual simulations of colonic fermentation. Highest hydrolysis rate was obtained for GalA-Rha-GalA trisaccharide, while the presence of partial negative charges and high radius of gyration enhance short chain fatty acid formation in distal colon. Established structure-activity relationships could help the rational design of prebiotics and clinical trials., This work has been funded by MICINN of Spain, Projects AGL2014-53445-R and AGL2017-84614-C2-1-R. Carlos Sabater thanks his FPU Predoc contract from Spanish MECD (FPU14/03619) and Postdoctoral research contract funded by the Instituto de Investigación Sanitaria del Principado de Asturias (ISPA).

In this work, two Peruvian beverages “Masato de Yuca,” typical of the Amazonian communities made from cassava (Manihot esculenta), and “Chicha de Siete Semillas,” made from different cereal, pseudo-cereal, and legume flours, were explored for the isolation of lactic acid bacteria after obtaining the permission of local authorities following Nagoya protocol. From an initial number of 33 isolates, 16 strains with different RAPD- and REP-PCR genetic profiles were obtained. In Chicha, all strains were Lactiplantibacillus plantarum (formerly Lactobacillus plantarum), whereas in Masato, in addition to this species, Limosilactobacillus fermentum (formerly Lactobacillus fermentum), Pediococcus acidilactici, and Weissella confusa were also identified. Correlation analysis carried out with their carbohydrate fermentation patterns and enzymatic profiles allowed a clustering of the lactobacilli separated from the other genera. Finally, the 16 strains were submitted to a static in vitro digestion (INFOGEST model) that simulated the gastrointestinal transit. Besides, their ability to adhere to the human epithelial intestinal cell line HT29 was also determined. Following both procedures, the best probiotic candidate was Lac. plantarum Ch13, a robust strain able to better face the challenging conditions of the gastrointestinal tract and showing higher adhesion ability to the intestinal epithelium in comparison with the commercial probiotic strain 299v. In order to characterize its benefit for human health, this Ch13 strain will be deeply studied in further works. © 2021, The Author(s). Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by the Ibero-American Programme on Science and Technology for Development (CYTED), grant number 917PTE0537. The Spanish team was funded by the “Agencia Estatal de Investigación” and the “Fondo Europeo de Desarrollo Regional” (AEI/FEDER, UE), grant number PCIN2017-075″. The Peruvian team was funded by the National Council of Science and Technology and Innovation of Peru through its execution unit National Fund for Scientific, Technological and Technological Innovation (CONCYTEC/FONDECYT), grant No. 001–2017.

An enzymatic procedure to obtain modified artichoke pectin and pectic oligosaccharides (POS) (Mw 100–0.3 kDa) has been optimised through an experimental design analysed by artificial neural networks (ANN; R2 0.99), leading to high yields of these products (65.9 ± 2.1 mg 100 mg−1 pectin) at optimal conditions (pH 4.41, reaction time 0.9 h, enzyme dose 17.1 U g−1 pectin), reaching a maximum theoretical desirability of 0.98. Desirability function, variable importance and sensitivity analysis were performed to interpret ANN while residual analysis demonstrated its high predictive power. Hydrolysates were purified by ultrafiltration and retentate and permeate fractions were characterised by MALDI-TOF-MS. Oligosaccharides from di- to hexasaccharides corresponding to galacturonic acid (GalA) oligomers that may be attached to neutral sugars and ferulic acid were determined, and their potential free radical scavenger activity was calculated using an in silico model (72–98% probability). The presence of specific structures in permeate (high free GalA content, GalA oligomers attached to xylose, ferulic acid or rhamnose and arabinose) and retentate fractions explained differences observed in their in vitro antioxidant activities (135.6 and 32.1 μmol Trolox g−1, respectively). The combination of in silico and in vitro methods allows establishing structure-activity relationships for modified pectin and POS fractions., This work has been funded by MICINN of Spain, Projects AGL2014-53445-R and AGL2017-84614-C2-1-R. Carlos Sabater thanks his FPU Predoc contract from Spanish MECD (FPU14/03619).

[Background] Food waste management is a key issue to global food security and friendly environmental governance. Worldwide, one-third of food produced for human consumption is lost or wasted along the food supply chain, primary production and food processing representing the most significant loses. Therefore, the need to achieve zero waste production schemes is becoming a priority to meet Sustainable Development Goals. Increasing evidence points towards vegetable food waste as a rich source of a wide array of carbohydrate structures and fibres providing the opportunity to identify and develop alternative approaches to valorize agro-food waste., [Scope and approach] This review describes the valorization of vegetable waste and by-products via production of (novel) substrates targeted to gut microbiota modulation, emphasizing the importance of raw materials and structural-functional properties of carbohydrates. Furthermore, we propose a novel framework for the rational selection of vegetable sources with potential prebiotic activity, based on machine learning and other computational tools applied to available literature and public database information., [Key findings and conclusions] Integration of the body of knowledge within the field of vegetable food waste valorization, from different perspectives, allows a rational selection of carbohydrate-based substrates with promising prebiotic activities. By exploring the interactions among dietary fibre and gut microbial ecosystems using computational tools fed with structural, functional and genomic data, we can identify substrates with potential to selectively stimulate gut commensals, in agreement with experimental evidence. Our approach establishes a new framework that can be extended to a wide range of commensal microbes and carbohydrate structures., The work in our research groups was funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No 818368 (MASTER), and the grants RTI 2018-095021-J-I00 (funded by (MCIU/AEI/FEDER, UE), AGL 2017-84614-C2-1-R and AGL 2016-78311-R (funded by (MINECO/AEI/FEDER, UE). Carlos Sabater acknowledges his Postdoctoral research contract funded by the Instituto de Investigación Sanitaria del Principado de Asturias (ISPA) and Postdoctoral research contract Juan de la Cierva-Formación from Spanish Ministry of Science and Innovation (FJC 2019-042125-I).

Our aim was to determine the effect of diet on gut microbiota, digestive function and sensations, using an integrated clinical, metagenomics and metabolomics approach. We conducted a cross-over, randomised study on the effects of a Western-type diet versus a fibre-enriched Mediterranean diet. In 20 healthy men, each diet was administered for 2 weeks preceded by a 2-week washout diet. The following outcomes were recorded: (a) number of anal gas evacuations, (b) digestive sensations, (c) volume of gas evacuated after a probe meal, (d) colonic content by magnetic resonance imaging, (e) gut microbiota taxonomy and metabolic functions by shotgun sequencing of faecal samples, (f) urinary metabolites using untargeted metabolomics. As compared to a Western diet, the Mediterranean diet was associated with (i) higher number of anal gas evacuations, (ii) sensation of flatulence and borborygmi, (iii) larger volume of gas after the meal and (iv) larger colonic content. Despite the relatively little difference in microbiota composition between both diets, microbial metabolism differed substantially, as shown by urinary metabolite profiles and the abundance of microbial metabolic pathways. The effects of the diet were less evident in individuals with robust microbiotas (higher beta-diversity). To conclude, healthy individuals tolerate dietary changes with minor microbial modifications at the composition level but with remarkable variation in microbial metabolism.

Through a combination of atomistic spin-lattice dynamics simulations and relativistic ab initio calculations of electronic transport we shed light on unexplained electrical measurements in nickel nanocontacts created by break junction experiments under cryogenic conditions (4.2 K). We implement post-self-consistent-field corrections in the conductance calculations to account for spin-orbit coupling and the noncollinearity of the spins, resulting from the spin-lattice dynamics. We find that transverse magnetic domain walls are formed preferentially in (111)-oriented face-centered-cubic nickel atomic-sized contacts, which also form elongated constrictions, giving rise to enhanced individual domain wall magnetoresistance. Our calculations show that the ambiguity surrounding the conductance of a priori uniformly magnetized nickel nanocontacts can be traced back to the crystallographic orientation of the nanocontacts, rather than spontaneously formed magnetic domain walls “pinned” at their narrowest points. This work was supported by the Generalitat Valenciana through Grant No. PROMETEO2017/139. C.S. gratefully acknowledges financial support from the Dean Fellowship of the Weizmann Institute of Science and Generalitat Valenciana (Grant No. CDEIGENT2018/028). O.T. appreciates the support of the Harold Perlman family, and acknowledges funding by a research grant from Dana and Yossie Hollander, the Israel Science Foundation (Grant No. 1089/15), the Minerva Foundation (Grant No. 120865), and The Ministry of Science and Technology of Israel (Grant No. 3-16244). J.J.P. acknowledges financial support from Spanish MINECO through Grants No. FIS2016-80434-P and No. PID2019-109539GB-C43, the Fundación Ramón Areces, the María de Maeztu Program for Units of Excellence in R&D (Grant No. CEX2018-000805-M), the Comunidad Autónoma de Madrid through the Nanomag COST-CM Program (Grant No. S2018/NMT-4321), the European Union Seventh Framework Programme under Grant Agreement No. 604391 Graphene Flagship, the Centro de Computación Científica of the Universidad Autónoma de Madrid and the computer resources at MareNostrum and the technical support provided by the Barcelona Supercomputing Center (Grant No. FI-2019-2-0007). The SLD and DFT calculations in this paper were performed on the high-performance computing facilities of the University of Alicante and the University of South Africa.

Bacteria-host interactions are mediated by different microbial associated molecular patterns which are most often surface structures such as, among others, exopolysaccharides (EPSs). In this work, the capability of two isogenic EPS-producing Bifidobacterium animalis subsp. lactis strains to modulate the gut microbiota of healthy mice, was assessed. Each strain produces a different type of polymer; the ropy strain S89L synthesized a rhamnose-rich, high-molecular weight EPS in highest abundance than the non-ropy DMS10140 one. BALB/c mice were orally fed for 10 days with milk-bifidobacterial suspensions and followed afterward for 7 post-intervention days (wash-out period). The colonic content of mice was collected in several sampling points to perform a metataxonomic analysis. In addition, the influence of specific microbial clades, apparently stimulated by the ropy and non-ropy strains, on mouse plasmatic cytokine levels was investigated through hierarchical association testing. Analysis of 16S rRNA gene sequences showed that the abundance of Firmicutes phylum significantly increased 7 days after cessing the treatment with both strains. The relative abundance of Alloprevotella genus also rose, but after shorter post-treatment times (3 days for both DMS10140 and S89L strains). Some bacterial clades were specifically modulated by one or another strain. As such, the non-ropy DMS10140 strain exerted a significant influence on Intestinomonas genus, which increased after 4 post-administration days. On the other hand, feeding with the ropy strain S89L led to an increase in sequences of Faecalibaculum genus at 4 post-treatment days, while the abundance of Erysipelotrichaceae and Lactobacillaceae families increased for prolonged times. Association testing revealed that several lactobacilli and bifidobacterial significantly stimulated by ropy S89L strain were positively associated with the levels of certain cytokines, including IL-5 and IL-27. These results highlight relevant changes in mice gut microbiota produced after administration of the ropy S89L strain that were associated to a potential immune modulation effect.

Atomic-sized contacts of iron, created in scanning tunneling microscope break junctions, present unusually high values of conductance compared to other metals. This result is counterintuitive since, at the nanoscale, body-centered-cubic metals are expected to exhibit lower coordination than face-centered-cubic metals. In this work we first perform classical molecular dynamics simulations of the contact rupture, using two different interatomic potentials. The first potential is isotropic, and produces mostly single-atom prerupture contacts. The second potential accounts for the directional bonding in the materials, and produces mostly highly coordinated prerupture structures, generally consisting of more than one atom in contact. To compare the two different types of structures with experiments, we use them as input to density functional theory electronic transport calculations of the conductance. We find that the highly coordinated structures, obtained from the anisotropic potential, yield higher conductances which are statistically in better agreement with those measured for body-centered-cubic iron. We thus conclude that the directional bonding plays an important role in body-centered-cubic metals. This work was supported by the Generalitat Valenciana through PROMETEO2017/139 and GENT (CDEIGENT2018/028), the Spanish government through Grants No. MAT2016-78625-C2-1-P and No. FIS2016-80434-P, and the Spanish Ministry of Science and Innovation, through the “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000805-M), by Comunidad Autónoma de Madrid through Grant No. S2018/NMT-4321 (NanomagCOST-CM), by the Fundación Ramón Areces, and by the European Union Graphene Flagship under Grant No. 604391.

Vancomycin, a branched tricyclic glycosylated peptide antibiotic, is a last-line defence against serious infections caused by staphylococci, enterococci and other Gram-positive bacteria. Orally-administered vancomycin is the drug of choice to treat pseudomembranous enterocolitis in the gastrointestinal tract. However, the risk of vancomycin-resistant enterococcal infection or colonization is significantly associated with oral vancomycin. Using the powerful matrix-free assay of co-sedimentation analytical ultracentrifugation, reinforced by dynamic light scattering and environmental scanning electron microscopy, and with porcine mucin as the model mucin system, this is the first study to demonstrate strong interactions between vancomycin and gastric and intestinal mucins, resulting in very large aggregates and depletion of macromolecular mucin and occurring at concentrations relevant to oral dosing. In the case of another mucin which has a much lower degree of glycosylation (~60%) – bovine submaxillary mucin - a weaker but still demonstrable interaction is observed. Our demonstration - for the first time - of complexation/depletion interactions for model mucin systems with vancomycin provides the basis for further study on the implications of complexation on glycopeptide transit in humans, antibiotic bioavailability for target inhibition, in situ generation of resistance and future development strategies for absorption of the antibiotic across the mucus barrier., The authors are grateful for a grant from the Independent Diabetes Trust (G.G.A. and S.E.H.) and the Engineering and Physical Sciences Research Council, grant number EP/L015633/1 (I.F., S.E.H., G.G.A., V.D.).

As the first of a series of molecular solenoids, two classes of dithia[7]helicenes (coil-shaped molecules with sulfur atoms integrated within a helical conjugated system) have been devised and synthesized to be used in molecular electronics. We used a modular assembly of fragments using Pd catalyzed coupling reactions and a final photocyclization step for the syntheses; this strategy gave us straightforward access to helicenes bearing thiophene end rings with either

The carbohydrate fraction of functional yogurts supplemented with citrus and artichoke pectin and their pectic oligosaccharides (POS) has been characterised, including carbohydrates from raw material (milk, pectin and POS) and formed during yogurt manufacture (POS and galactooligosaccharides GOS). Viable cell count and pH values accomplished the quality standards required for yogurts. The content of lactose and lactic and acetic acids was in the range 3.5–4.0; 0.85–1.16 and 0.04−0.07 g 100 g−1, respectively. Other sugars from pectin (arabinose, galacturonic acid, POS), milk (glucose, galactose, myo-inositol and GOS, GOS) were also quantified. GC-EI-MS spectra of yogurt carbohydrates were classified using machine learning, and structure-relative retention time relationships were calculated determining the abundance of specific fragments on larger oligosaccharide structures. All information generated was correlated using a convolutional network that established characteristic patterns in the complete carbohydrate fraction of each yogurt, as well as changes during fermentation in the carbohydrate profile. It was found that di-, tri- and tetra-POS formed by rhamnose and xylose attached to acetylated-galacturonic acid were released during fermentation in yogurts with artichoke POS. Structures elucidated by these algorithms were confirmed by MALDI-TOF-MS. These models may allow structural differences to be determined among novel oligosaccharides present in food matrices., This work has been funded by MICINN: Ministry of Science and Innovation of Spain, Projects AGL2014-53445-R and AGL2017-84614-C2-1-R. Carlos Sabater thanks his FPU Predoc contract from Spanish MECD (FPU14/03619).