Sustainable one-pot immobilization of enzymes in/on metal-organic framework materials

peer-reviewedThe industrial use of enzymes generally necessitates their immobilization onto solid supports. The well-known high affinity of enzymes for metal-organic framework (MOF) materials, together with the great versatility of MOFs in terms of structure, composition, functionalization and synthetic approaches, has led the scientific community to develop very different strategies for the immobilization of enzymes in/on MOFs. This review focuses on one of these strategies, namely, the one-pot enzyme immobilization within sustainable MOFs, which is particularly enticing as the resultant biocomposite Enzyme@MOFs have the potential to be: (i) prepared in situ, that is, in just one step; (ii) may be synthesized under sustainable conditions: with water as the sole solvent at room temperature with moderate pHs, etc.; (iii) are able to retain high enzyme loading; (iv) have negligible protein leaching; and (v) give enzymatic activities approaching that given by the corresponding free enzymes. Moreover, this methodology seems to be near-universal, as success has been achieved with different MOFs, with different enzymes and for different applications. So far, the metal ions forming the MOF materials have been chosen according to their low price, low toxicity and, of course, their possibility for generating MOFs at room temperature in water, in order to close the cycle of economic, environmental and energy sustainability in the synthesis, application and disposal life cycle

Abandono de terrazas de cultivo: recolonización vegetal y erosión en el sureste peninsular

[Resumen] El paisaje del sureste peninsular ha estado marcado, en los últimos decenios, por los cambios en los aprovechamientos de las laderas subáridas. Frente a concepciones lineales de los procesos erosivos que afectan a estos espacios, la metodología empleada y los resultados obtenidos evidencian la necesidad de abordar este tema con planteamientos puramente geográficos, donde se valora el papel de los factores abióticos y bióticos del medio, sin olvidar que ambos son decisivos en la comprensión y explicación del paisaje desde una visión antropocéntrica.[Abstract] In the last decades the southeast peninsular landscape has been affected by the changes in the used subarid slopes. Opposite to lineal conceptions of erosive processes in these areas, the employed methodology and the obtained resu1ts show the need to research this subject with purely geographic patterns in which the abiotic and biotic factors are valued without forgetting that both are decisives in the understanding and explication of the lanscape from an human perspectiv

¿Asedio a la Justicia Fiscal en Europa? (Reflexiones ante la Jurisprudencia Comunitaria sobre las Cláusulas Antiabuso y la reacción del legislador español)

Tras la sentencia Lankhorst España ha suprimido la subcapitalización y la transparencia fiscal internacional en el ámbito de la Unión Europea. Alemania ha optado por extender la subcapitalización a los préstamos de residentes, pero sometiéndola a tales requisitos que resulta dudosa su eficacia. Si tenemos en cuenta que las libertades comunitarias se proyectan –en parte– sobre los Estados del Espacio Económico Europeo y los Estados Asociados podemos llegar a la conclusión de que la jurisprudencia comunitaria ha puesto sitio a la Justicia fiscal en Europa. El único instrumento que –prácticamente– resta a los Estados miembros es la cláusula general anti-fraude (nuestro antiguo fraude de ley y futuro «conflicto» en la aplicación de las normas), pero tales mecanismos son complejos de aplicar, lo que les resta eficacia si no se completan con cláusulas específicas. Ante esta situación cabría proponer el establecimiento de cláusulas específicas aplicables de modo general a residentes y no residentes basadas en presunciones iuris tantum en el caso de que afecten a no residentes siempre que otra solución resultara impracticable y más perniciosa para las libertades comunitarias. Por otro lado, sería conveniente un giro en la jurisprudencia comunitaria, pues la defensa a ultranza de las libertades comunitarias, al privilegiar a los grandes operadores económicos, está dificultando el pleno ejercicio de dichas libertades por las pequeñas empresas. En este sentido, podría afirmarse que una mínima garantía de la tributación con arreglo a la capacidad económica constituye un presupuesto lógico para un adecuado ejercicio de las libertades comunitarias. También sería preciso reformular el principio de coherencia en la jurisprudencia comunitaria, de modo que se aplique al grupo de sociedades y al conjunto de la situación fiscal teniendo en cuenta también los efectos de los Convenios de Doble Imposición. De este modo el Tribunal se convertiría en un auténtico adalid de las libertades comunitarias sin riesgos de favorecer tan sólo a los grandes grupos económicos

Correlating Antimicrobial activity and Structure in Montmorillonite modified with Hexadecyltrimethylammonium and Silver

The relationship between antimicrobial properties and structure of montmorillonite (MMT) containing hexadecyltrimethylammonium bromide (HDTMA-Br) and silver (Ag) was determined. HDTMA was adsorbed at the clay interlayer by a cation exchange, through the positive head of the ammonium group. At higher surfactant loadings (100 and 200% cation exchange capacity (CEC); MH1 and MH2 samples, respectively) the prevalence of weak adsorption (Van der Waals forces) was observed; whereas below the clay CEC (50%, MH0.5) strong interactions predominated (cation exchange). These different interactions impacted on antimicrobial activity, increasing bactericidal capacity when the surfactant was more available to diffuse. For organo-montmorillonites (OMMT) and all samples with Ag, zeta potential pointed out electrical charge changes on the outer surface, respect to MMT. XPS analyses showed peaks attributed to clusters formation, silver oxidation, and Ag0 in MMTAg and MH0.5-Ag. The Ag0 peak was also present in MH1-Ag and MH2-Ag, the later showing an extra peak associated with AgBr. HDMTA+ and Ag adsorbed on the MMT acted synergistically against Staphylococcus aureus. This effect was less noticeable for Escherichia coli and the result was attributed to both, E. coli outer envelope which might lower the efficacy of HDMTA+ adsorbed on the MMT, and decreasing silver proportions when the surfactant loading increased. MH1-Ag presented the best bactericidal properties, showing synergistic effects against S. aureus, while maintaining activity against E. coli compared to MMT-Ag. Understanding MMT-HDMTA-Ag efficacy contributes to the design of new antimicrobial materials for potential applications in health careFil: Fernández Solarte, Alejandra María. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina. Corporacion Universitaria Minuto de Dios.; ColombiaFil: Blanco Massani, Mariana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Molina, Vanesa Magali. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Benítez Guerrero, Mónica. Universidad de Malaga. Facultad de Ciencias; EspañaFil: Torres Sánchez, Rosa M.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentin

Dye-conjugated complementary lipophilic nucleosides as useful probes to study association processes by fluorescence resonance energy transfer

Modern supramolecular chemistry relies on the combination of diverse analytical techniques that can provide complementary information on complex self-assembly landscapes. Among them, resonance energy transfer, monitored by fluorescence emission spectroscopy, arises as a sensitive and convenient phenomenon to report binding intermolecular interactions. The use of molecular probes labelled with suitable complementary energy-transfer pairs can provide valuable information about the thermodynamics, kinetics and self-sorting characteristics of a particular self-assembled system. The objective of this work is to generate a set of nucleoside FRET probes that can be reliably employed to prove and analyse quantitatively H-bonding interactions between complementary Watson-Crick pairs. We first describe the preparation of a set of lipophilic nucleosides that are linked to a π-conjugated functional fragment. The bases include guanosine and 2-aminoadenosine as purine heterocycles, and cytidine and uridine as complementary pyrimidine bases. The π-conjugated moiety comprises either a short phenylene-ethynylene oligomer, a bithiophene, or a BODIPY dye. We then demonstrate that the last two chromophores constitute an energy donor-acceptor couple and that donor emission quenching can be related to the ratio of molecules bound to the complementary acceptor pair. Hence, fluorescence spectroscopy in combination with resonance energy transfer, is shown here to be a useful tool to study and quantify the association and self-sorting events between complementary and non-complementary nucleosides in apolar aromatic solvents, where the binding strength is considerably high, and sensitive techniques that employ low concentrations are demandedFunding from the European Research Council (ERC-Starting Grant 279548 PROGRAM-NANO) and MINECO (CTQ2014-57729-P) is gratefully acknowledged. E. F. would like to thank the Sharif University of Technology of Iran for financial support. D. S.M. would like to acknowledge Comunidad de Madrid for financial support through contract PEJ16/IND/AI-084

Proteomic profile of the effects of low-dose bisphenol A on zebrafish ovaries

Human exposure to bisphenol-A (BPA) is largely unavoidable because BPA is an environmental contaminant found in soil, water, food and indoor dust. The safety of authorized BPA amounts in consumer products is under question because new studies have reported adverse effects of BPA at doses far below that previously established by the NOAEL (50 μg/kg per day). To protect public health, the consequences of low-dose BPA exposure in different organs and organismal functions must be further studied to generate relevant data. This study attempted to investigate the effects and potential molecular mechanisms of short-term exposure to 1 μg/L BPA on zebrafish ovarian follicular development. We observed only minor changes at the histopathological level with a small (3 %) increase in follicular atresia. However, a shotgun proteomics approach indicated deep alterations in BPA-exposed ovarian cells, including induction of the oxidative stress response, metabolic shifts and degradome perturbations, which could drive oocytes towards premature maturation. Based on these results, it could be suggested that inadvertent exposure to small concentrations of BPA on a continuous basis causes alteration in biological processes that are essential for healthy reproduction

Clinical aspects of usher syndrome and the USH2A gene in a cohort of 433 patients

IMPORTANCE A new statistical approach is needed to describe the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. OBJECTIVES To describe the primary phenotypic characteristics and differences between type I and type II Usher syndrome and to establish a phenotype-genotype correlation for the 2 most frequent mutations in the USH2A gene. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study at a genetics department, in which clinical evaluations were performed for 433 patients (297 unrelated families) who were classified as having type I, II, III, atypical, or unclassified Usher syndrome according to their clinical history, pedigree data, results from ophthalmological studies, and audiological, neurophysiological, and vestibular test results. Molecular studies were performed for 304 patients (256 unrelated families). The Mann-Whitney U test or the χ2 test was used for calculating the differences between mean values for the analyzed parameters. MAIN OUTCOMES AND MEASURES Age at diagnosis; age at onset of night blindness, visual field loss, visual acuity loss, and cataracts; and severity and age at diagnosis of hearing loss. RESULTS The comparison between patients with type I Usher syndrome and those with type II Usher syndrome revealed P < .001 for most items analyzed. The most frequent mutations in the USH2A gene were the p.Glu767Serfs*21 and p.Cys759Phe mutations, with an allelic frequency of 23.2%(63 of 272 alleles) and 8.1% (22 of 272 alleles), respectively. The phenotypic analysis for patients carrying p.Cys759Phe showed P < .001 for most items analyzed when compared with patients carrying p.Glu767Serfs*21 and when compared with patients carrying other mutations in the USH2A gene. None of the p.Cys759Phe patients exhibited a severe hearing loss phenotype, and more than 60%had only mild hearing loss. Most patients carrying the p.Glu767Serfs*21 mutation (72.1%) were moderately deaf. CONCLUSIONS AND RELEVANCE Our study presents the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. Detailed genotype-phenotype correlations, as presented in our study, allow for a better correlation of clinical signs with a known genotype and can improve the clinical management, genetic counseling, and risk assessment of patients with Usher syndrome because an estimated prognosis of their disease can be madeThis work was supported by grant PI13/00226 (to Servicio de Genética, Instituto de Investigación–Fundación Jiménez Díaz, Madrid, Spain), by grant PI13/00638 (to Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario y Politécnico La Fe, Valencia, Spain), and by grant 06/07/0036 (to Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain) from Fundaluce and Organización Nacional de Ciegos Españole